| 1. |
- Gustafson, Yngve, et al.
(författare)
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A geriatric-anesthesiologic program to reduce acute confusional states in elderly patients treated for femoral neck fractures
- 1991
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Ingår i: Journal of The American Geriatrics Society. - : Wiley. - 0002-8614 .- 1532-5415. ; 39:7, s. 655-662
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the effect of a geriatric-anesthesiologic intervention program for the prevention and treatment of acute confusional states (ACS) in elderly patients treated for femoral neck fractures. The intervention program was based on the results of previous prospective studies in similar patient populations. The outcome of the intervention, comprising 103 patients, was compared with that of an earlier study comprising 111 patients. The intervention program consisted of pre- and post-operative geriatric assessments, oxygen therapy, early surgery, prevention and treatment of peri-operative blood pressure falls and treatment of post-operative complications. The incidence of ACS was lower, 47.6%, in the intervention study compared with 61.3% (P less than 0.05) in the control study. Furthermore, the ACS that occurred in the intervention study was less severe and of shorter duration than that in the control study. The incidence of post-operative decubital ulcers, severe falls, and urinary retention was also lower. The mean duration of orthopedic ward stay was 17.4 days in the control study and 11.6 days in the intervention study (P less than 0.001). It can be concluded that the intervention program reduced the incidence, severity, and duration of ACS which resulted in a shortened orthopedic ward stay
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| 2. |
- Gustafson, Yngve, et al.
(författare)
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Underdiagnosis and poor documentation of acute confusional states in elderly hip fracture patients
- 1991
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Ingår i: Journal of The American Geriatrics Society. - : Wiley. - 0002-8614 .- 1532-5415. ; 39:8, s. 760-765
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Tidskriftsartikel (refereegranskat)abstract
- STUDY OBJECTIVE: To determine the accuracy of diagnosis and documentation of acute confusional states (ACS) in the medical records of patients with hip fracture. DESIGN: The diagnosis of ACS in two prospective clinical studies was compared to its diagnosis in the medical records of the same patients on the same hospitalization. In order to determine if the simultaneous prospective study influences the diagnostic and documentary practices evidenced in the medical records, a further comparison was done by reviewing medical records of two series of patients seen some years prior to the prospective studies. SETTING: Patients with femoral neck fractures treated at a department of orthopedic surgery in a university hospital and one retrospective control sample from a department of general surgery in a county hospital. SUBJECTS: Two prospective samples of patients 65 years and older treated for femoral neck fractures (n = 111 and n = 57, respectively) and two earlier retrospective samples (n = 66 and n = 68, respectively). MEASUREMENTS AND MAIN RESULTS: All comparisons showed that both physicians and nurses diagnosed ACS unsatisfactorily and documented the patients' mental status poorly. The analysis of the two retrospective medical record control samples gave the same results. Neither the physicians nor the nurses used any kind of diagnostic instrument to detect cognitive disorders in the patients. CONCLUSIONS: ACS is a common and severe complication in elderly people treated for femoral neck fractures. Acute confusional states have, by definition, one or more causes that can often be identified and treated. Poor assessment and documentation is a threat to the patients as a correct diagnosis of ACS is a prerequisite for further assessment of its underlying causes and the consequent necessary medical and nursing care.
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| 3. |
- Borg, A., et al.
(författare)
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Association of int2/hst1 coamplification in primary breast cancer with hormone-dependent phenotype and poor prognosis
- 1991
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 63:1, s. 136-142
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Tidskriftsartikel (refereegranskat)abstract
- The human proto-oncogene INT2 (homologous to the mouse INT2 gene, implicated in proviral induced mammary carcinoma) has been mapped to chromosome llql3 and found to share band localisation with, among others, the HST1 proto-oncogene. Both genes are members of the fibroblast growth factor family. In the present study, coamplification (2-15 copies) of the INT2/HST1 genes was found in 27 (9%) of 311 invasive human breast carcinomas using slot blot and Southern blot analyses. Amplification was not correlated to tumour size, axillary lymph node status or stage of disease, neither to patient age nor menopausal status. However, 26 (96%) of the 27 amplified tumours were, often strongly, Oestrogen receptor positive compared to 65% of the unamplified cases (P = 0. 001). These findings are in sharp contrast to the strong correlations of HER-2/neu proto-oncogene amplification with advanced stage and steroid receptor negativity, previously observed in the same series of tumours. Patients with INT2/HSTI amplified breast cancer had a significantly shorter disease-free survival compared to those with unamplified genes (P = 0. 015, median follow up 45 months). This correlation was confined to node-negative patients and persisted in multivariate analysis. No significant correlation to survival from breast cancer was found. It is concluded that amplification of the 1 lql3 region in breast cancer occurs in a particular subset of aggressive tumours, quite different from that identified by HER-2/neu amplification. It still remains to be shown that the selection for amplified genes at llql3 is due to the activity of INT2, HSTl or yet another, still unidentified, neighbouring gene. However, the results are potentially of clinical value in separating a group of node-negative breast cancer for more intense treatment.
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| 4. |
- Arvidsson, D, et al.
(författare)
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Splanchnic oxygen consumption in septic and hemorrhagic shock.
- 1991
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Ingår i: Surgery. - 0039-6060 .- 1532-7361. ; 109:2, s. 190-7
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen consumption (VO2) is dependent on oxygen delivery (DO2) in septic shock. Local hypoxia with later secondary organ failure may develop, however, despite an often hyperdynamic circulation. The splanchnic organs seem to be of vital importance in this context. In experiments performed in pigs we compared total body VO2 and DO2 with oxygen consumption and delivery in the gastrointestinal organs and the liver in two different shock states: (1) septic shock induced by peritonitis (n = 6) and (2) hemorrhagic shock (n = 6). Another group of six animals not in shock served as controls. Total, gastrointestinal, and liver DO2 decreased in a similar pattern in both septic and hemorrhagic shock. Gastrointestinal and liver VO2 increased in sepsis, whereas it was unchanged in hemorrhage. In the later phase of sepsis, liver VO2, but not gastrointestinal VO2, again decreased, because liver oxygen extraction was almost total and liver DO2 decreased further. The development of flow-dependent liver hypoxia was reflected in a decrease in liver lactate turnover (increased liver lactate release) during late sepsis. Early hypoxia in the splanchnic region is suggested as a plausible mechanism behind the development of secondary organ failure, especially in sepsis.
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| 5. |
- Askerlund, Per, et al.
(författare)
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NADH-Ferricyanide Reductase of Leaf Plasma Membranes : Partial Purification and Immunological Relation to Potato Tuber Microsomal NADH-Ferricyanide Reductase and Spinach Leaf NADH-Nitrate Reductase
- 1991
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Ingår i: Plant Physiology. - 0032-0889 .- 1532-2548. ; 95:1, s. 6-13
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Tidskriftsartikel (refereegranskat)abstract
- Plasma membranes obtained by two-phase partitioning of microsomal fractions from spinach (Spinacea oleracea L. cv Medania) and sugar beet leaves (Beta vulgaris L.) contained relatively high NADH-ferricyanide reductase and NADH-nitrate reductase (NR; EC 1.6.6.1) activities. Both of these activities were latent. To investigate whether these activities were due to the same enzyme, plasma membrane polypeptides were separated with SDS-PAGE and analyzed with immunoblotting methods. Antibodies raised against microsomal NADH-ferricyanide reductase (tentatively identified as NADH-cytochrome b5 reductase, EC 1.6.2.2), purified from potato (Solanum tuberosum L. cv Bintje) tuber microsomes, displayed one single band at 43 kilodaltons when reacted with spinach plasma membranes, whereas lgG produced against NR from spinach leaves gave a major band at 110 kilodaltons together with a few fainter bands of lower molecular mass. Immunoblotting analysis using inside-out and right-side-out plasma membrane vesicles strongly indicated that NR was not an integral protein but probably trapped inside the plasma membrane vesicles during homogenization. Proteins from spinach plasma membranes were solubilized with the zwitterionic detergent 3-[(3-cholamidopropyl) dimethylammonio] 1-propane-sulfonate and separated on a Mono Q anion exchange column at pH 5.6 with fast protein liquid chromatography. One major peak of NADH-ferricyanide reductase activity was found after separation. The peak fraction was enriched about 70-fold in this activity compared to the plasma membrane. When the peak fractions were analyzed with SDS-PAGE the NADH-ferricyanide reductase activity strongly correlated with a 43 kilodalton polypeptide which reacted with the antibodies against potato microsomal NADH-ferricyanide reductase. Thus, our data indicate that most, if not all, of the truly membrane-bound NADH-ferricyanide reductase activity of leaf plasma membranes is due to an enzyme very similar to potato tuber microsomal NADH-ferricyanide reductase (NADH-cytochrome b5 reductase).
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| 6. |
- Askerlund, Per, et al.
(författare)
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Transmembrane Electron Transport in Plasma Membrane Vesicles Loaded with an NADH-Generating System or Ascorbate
- 1991
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Ingår i: Plant Physiology. - 0032-0889 .- 1532-2548. ; 96:4, s. 1178-1184
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Tidskriftsartikel (refereegranskat)abstract
- Sugar beet (Beta vulgaris L.) leaf plasma membrane vesicles were loaded with an NADH-generating system (or with ascorbate) and were tested spectrophotometrically for their ability to reduce external, membrane-impermeable electron acceptors. Either alcohol dehydrogenase plus NAD+ or 100 millimolar ascorbate was included in the homogenization medium, and right-side-out (apoplastic side-out) plasma membrane vesicles were subsequently prepared using two-phase partitioning. Addition of ethanol to plasma membrane vesicles loaded with the NADH-generating system led to a production of NADH inside the vesicles which could be recorded at 340 nanometers. This system was able to reduce 2,6-dichlorophenolindophenol-3′-sulfonate (DCIP-sulfonate), a strongly hydrophilic electron acceptor. The reduction of DCIP-sulfonate was stimulated severalfold by the K+ ionophore valinomycin, included to abolish membrane potential (outside negative) generated by electrogenic transmembrane electron flow. Fe3+-chelates, such as ferricyanide and ferric citrate, as well as cytochrome c, were not reduced by vesicles loaded with the NADH-generating system. In contrast, right-side-out plasma membrane vesicles loaded with ascorbate supported the reduction of both ferric citrate and DCIP-sulfonate, suggesting that ascorbate also may serve as electron donor for transplasma membrane electron transport. Differences in substrate specificity and inhibitor sensitivity indicate that the electrons from ascorbate and NADH were channelled to external acceptors via different electron transport chains. Transplasma membrane electron transport constituted only about 10% of total plasma membrane electron transport activity, but should still be sufficient to be of physiological significance in, e.g. reduction of Fe3+ to Fe2+ for uptake.
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| 7. |
- Blomberg, E, et al.
(författare)
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Adsorbed layers of human serum albumin investigated by the surface force technique
- 1991
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Ingår i: Journal of Dispersion Science and Technology. - 0193-2691 .- 1532-2351. ; 12, s. 179-200
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between human serum albumin (HSA) layers adsorbed from solution onto muscovite mica have been investigated by means of surface force measurements. The effects of varying the ionic strength and the serum albumin concentration have been studied at pH=5.5. The negatively charged protein cannot be desorbed from the negatively charged mica surface by dilution with water. The thickness of the (compressed) adsorbed layer is small compared to the dimension of HSA, except at the highest concentration used (1mg/ml). Hence, under a compressive load at low packing densities the protein conformation on the surface is different from that in bulk solution. No adhesion was observed when the amount adsorbed was large. However, an attractive
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| 8. |
- Blomgren, Y, et al.
(författare)
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Concentration of acid hydrolysate by reverse osmosis and mechanical vapor recompression evaporation
- 1991
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Ingår i: Journal of Wood Chemistry and Technology. - : Informa UK Limited. - 0277-3813 .- 1532-2319. ; 11:1, s. 117-135
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this project was to investigate possible methods for the concentration of acid hydrolyzate obtained from hydrolyzing wood. A detailed study of concentration of sugar solution by reverse osmosis, RO, has been performed as well as a comparison with mechanical vapor recompression evaporation. The comparison has, in this specific case, shown that RO is currently more expensive. The result is, however, highly dependent on investment costs, and future expansion of membrane technology could mean lower area costs which would favor the technology.
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| 9. |
- Carlfors, J, et al.
(författare)
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Lidocaine in microemulsion - A dermal delivery system
- 1991
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Ingår i: Journal of Dispersion Science and Technology. - 0193-2691 .- 1532-2351. ; 12, s. 467-482
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Tidskriftsartikel (refereegranskat)abstract
- In order to obtain a microemulsion that is stable at skin tempeature, the regions of existance of microemulsions of water and isoproptyl myristate were studied as a function of hydrophilelipophile balance (HLB) of nonionic surfactant mixtures. The microemulsion dissolves large amount of the local anaesthetic lidocaine. The amount of dissolved lidocaine in the microemulsion was proportional to the isopropyl myristate content and limited to its solubility in this solvent. The addition of lidocaine lowered the phase inversion temperature (PIT) of the system and increased the temperature range for microemulsion stability. The structure of the microemulsion, as investigated by proton Fourier transform pulsed-gradient spin-echo NMR spectroscopy, was found to be bicontinous. The physico-chemical properties of the microemulsion as well as the low toxicity of its components result in formulation intendend for topical administation.
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| 10. |
- Fredlund, Kenneth M., et al.
(författare)
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Oxidation of external NAD(P)H by purified mitochondria from fresh and aged red beetroots (Beta vulgaris L.)
- 1991
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 97:1, s. 99-103
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondria were isolated from fresh beetroots (Beta vulgaris L. cvs Rubria and Nina) by differential centrifugation followed by Percoll gradient centrifugation. These purified mitochondria oxidized external NADH, although relatively slowly (20-40 versus 100-120 nanomoles oxygen per minute times milligram protein for NADH and succinate oxidation, respectively), with respiratory control ratios of two to three and ADP/O ratios of 1.2 to 1.6. NADPH was also oxidized, but even more slowly and with little or no coupling. The optimum for both NADH and NADPH oxidation by fresh beetroot mitochondria was pH 6. The rate of external NADH oxidation by isolated mitochondria was enhanced threefold during storage of the intact tubers at 10°C for 12 weeks. The optimum of the induced NADH oxidation was approximately pH 6.8. Succinate and malate oxidation only increased by 30% during the same period and NADPH oxidation was constant. This is strong evidence that NADH and NADPH oxidation are catalyzed by different enzymes at least in beetroots. Activity staining of nondenaturing polyacrylamide gels with NADH and Nitro Blue Tetrazolium did not show differences in banding pattern between mitochondria isolated from fresh and stored beetroots. The induction is discussed in relation to physiological aging processes.
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| 11. |
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| 12. |
- HALL, GF, et al.
(författare)
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AN ORGANIC-PHASE ENZYME ELECTRODE FOR CHOLESTEROL
- 1991
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Ingår i: Analytical Letters. - : Taylor andamp;amp; Francis. - 0003-2719 .- 1532-236X. ; 24:8, s. 1375-1388
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Tidskriftsartikel (refereegranskat)abstract
- An enzyme electrode is described for the determination of cholesterol dissolved in chloroform/hexane (1:1). The enzyme electrode is shown to be applicable to the determination of cholesterol in samples of butter and margarine.
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| 13. |
- HU, J, et al.
(författare)
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AN ENZYME ELECTRODE FOR GLUCOSE CONSISTING OF GLUCOSE-OXIDASE IMMOBILIZED AT A BENZOQUINONE-MODIFIED CARBON ELECTRODE
- 1991
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Ingår i: Analytical Letters. - : Taylor andamp;amp; Francis. - 0003-2719 .- 1532-236X. ; 24:1, s. 15-24
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes an amperometric enzyme electrode for the analysis of glucose. The glucose sensor utilised adsorbed benzoquinone on a carbon electrode to mediate electron transfer from glucose oxidase. A linear response to 0-15 mM glucose was observed. The electrodes response to glucose, its pH profile and the effect of temperature are presented.
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| 14. |
- Kempe, Maria, et al.
(författare)
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Binding studies on substrate- and enantio-selective molecularly imprinted polymers
- 1991
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Ingår i: Analytical Letters. - : Informa UK Limited. - 0003-2719 .- 1532-236X. ; 24:7, s. 1137-1145
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Tidskriftsartikel (refereegranskat)abstract
- A molecularly imprinted polymer was prepared using tert-butyloxycarbonyl-L-phenylalanine as the print molecule and methacrylic acid as the functional monomer. The bulk polymer obtained was ground, sieved, packed into a column and investigated in the HPLC-mode by frontal chromatography to determine the number of binding sites and dissociation constants for the enantiomers interacting with the polymer. The dissociation constant for the L-enantiomer of the print molecule was lower than for the D-enantiomer (6.3 mM and 8.1 mM, respectively). This means that the affinity for the L-enantiomer was higher than for the D-enantiomer. The number of binding sites in the polymer giving rise to these dissociation constants were determined to be 28 μmol per g dry polymer.
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| 15. |
- Lapointe, Line, et al.
(författare)
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Resistance to low temperature photoinhibition is not associated with isolated thylakoid membranes of winter rye.
- 1991
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 97:2, s. 804-810
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Tidskriftsartikel (refereegranskat)abstract
- In vivo measurements of chlorophyll a fluorescence indicate that cold-hardened winter rye (Secale cereale L. cv Musketeer) develops a resistance to low temperature-induced photoinhibition compared with nonhardened rye. After 7.2 hours at 5 degrees C and 1550 micromoles per square meter per second, the ratio of variable fluorescence/maximum fluorescence was depressed by only 23% in cold-hardened rye compared with 46% in nonhardened rye. We have tested the hypothesis that the principal site of this resistance to photoinhibition resides at the level of rye thylakoid membranes. Thylakoids were isolated from cold-hardened and nonhardened rye and exposed to high irradiance (1000-2600 micromoles per square meter per second) at either 5 or 20 degrees C. The photoinhibitory response measured by room temperature fluorescence induction, photosystem II electron transport, photoacoustic spectroscopy, or [(14)C]atrazine binding indicates that the differential resistance to low temperature-induced photoinhibition in vivo is not observed in isolated thylakoids. Similar results were obtained whether isolated rye thylakoids were photoinhibited or thylakoids were isolated from rye leaves preexposed to a photoinhibitory treatment. Thus, we conclude that increased resistance to low temperature-induced photoinhibition is not a property of thylakoid membranes but is associated with a higher level of cellular organization.
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| 16. |
- Ledin, Torbjörn, et al.
(författare)
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Chronic toxic encephalopathy investigated using dynamic posturography
- 1991
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Ingår i: American Journal of Otolaryngology. - 0196-0709 .- 1532-818X. ; 12:2, s. 96-100
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Tidskriftsartikel (refereegranskat)abstract
- Seven male patients previously exposed to industrial solvents and diagnosed with chronic toxic encephalopathy (aged 38 to 69 years; mean age, 56 years) were investigated by dynamic posturography and compared with healthy, age-matched male control patients. Dynamic posturography comprises two phases: a sensory organization (SO) phase, in which the support surface and visual surround are either stable or referenced to the patient's sway, with eyes open or closed, and a movement coordination (MC) phase, in which the platform makes active movements. In SO testing, the patient group showed significantly impaired equilibrium performance compared with the control group in most test conditions. The MC test revealed no differences between groups. A relationship was found between the equilibrium score resulting from SO testing with stable support and visual surround and the sway area of the confidence ellipse elicited 3 years previously by static posturography with eyes open. We conclude that patients with chronic toxic encephalopathy have impaired equilibrium, as demonstrated by dynamic posturography testing.
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| 17. |
- Ljunghall, S., et al.
(författare)
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Disturbance of basal and stimulated serum levels of intact parathyroid hormone in primary hyperparathyroidism
- 1991
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Ingår i: Surgery. - 0039-6060 .- 1532-7361. ; 110:1, s. 47-53
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Tidskriftsartikel (refereegranskat)abstract
- In patients with primary hyperparathyroidism, measurements were made of basal and stimulated levels of intact parathyroid hormone (PTH). The basal PTH values were elevated in all but six of 89 patients and provided clear separation towards normal individuals (n = 75) and patients with hypercalcemia of other origin (n = 34). The PTH value correlated with the serum calcium concentration in hyperparathyroidism and with the weight of excised parathyroid adenomas but not with that of chief cell hyperplasias. A constant ethylenediaminetetraacetic acid infusion during 60 minutes of induced essentially linear reductions of plasma-ionized calcium concentrations, averaging 0.02 mmol/L/10 minutes, which were associated with swift, curvilinear, elevations of PTH levels that reached a plateau after 10 to 20 minutes. The increment in serum PTH level correlated with the basal PTH value both in patients with hyperparathyroidism and controls. However, in proportion to the much greater glandular mass in the patients with hyperparathyroidism, the secretion of PTH was relatively reduced. The findings support the value of the intact PTH assay in the differential diagnosis of hypercalcemia and show that PTH secretion in vivo is extremely sensitive to hypocalcemic stimulation, that the pathological parathyroid tissue in hyperparathyroidism is characterized by a reduction of hormone release per unit weight, and that the hormone secretion in hyperparathyroidism operates closer to its maximal capacity than under normal circumstances.
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| 18. |
- Nordén, Bengt, 1945, et al.
(författare)
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DNA INTERACTION WITH CHIRAL METAL-COMPLEXES
- 1991
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Ingår i: Nucleosides and Nucleotides. - : Informa UK Limited. - 0732-8311 .- 1532-2335. ; 10:1-3, s. 195-205
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Tidskriftsartikel (refereegranskat)abstract
- Despite extensive study of DNA interaction with propeller-shaped metal complexes, such as the DELTA and LAMBDA enantiomers of [Ru(1,10-phenanthroline)3]2+, the basis for their enantioselectivity, and even their binding modes, are not yet fully understood. H-1 NMR studies of the interactions with the self-complementary oligonucleotide d(CGCGATCGCG)2 indicate that both enantiomers bind into the minor groove of the central AT-TA region, but with a rapid exchange between the bound and free states. Flow linear dichroism (FLD) and circular dichroism (CD) show different binding geometries for the two enantiomers. These two geometries are found in natural DNA as well as in a number of different B form polynucleotides, virtually independent of base composition and of methylation. The DNA interaction with the [Ru(1,10-phenanthroline)3]2+ complexes will be reconsidered in the light of NMR, FLD, CD and fluorescence results.
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| 19. |
- Olsson, Henny M, et al.
(författare)
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Nursing education and definition of the professional nurse role. Expectations and knowledge of the nurse role
- 1991
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Ingår i: Nurse Education Today. - 0260-6917 .- 1532-2793. ; 11:1, s. 30-36
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Tidskriftsartikel (refereegranskat)abstract
- The aim of nursing education is a development of the nursing profession. One way to promote development is to clarify the professional role. The role definition for nursing is mostly transmitted through tacit knowledge. We consider that the professional development of the nursing profession in Sweden requires a clear and well-defined nurse role. Stated goals of professional programmes for nursing do not include the entire body of tacit knowledge. The overall development requires recognition of a professional status together with a clear and well-defined role. We have found a significant change in the distribution of role-conceptions which occurred after the nurses had experienced their first year as registered nurses, and which did not occur during the educational process. This indicates that the conceptions of the need for a more clearly defined nursing role are assimilated during work experience. This confirms the necessity and importance of role modelling, role repetition and interactions with a professional group as part of the educational process.
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| 20. |
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| 21. |
- Pennell, Roger I., et al.
(författare)
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Developmental regulation of a plasma membrane arabinogalactan protein epitope in oilseed rape flowers
- 1991
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Ingår i: Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 3, s. 1317-1326
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Tidskriftsartikel (refereegranskat)abstract
- We have identified and characterized the temporal and spatial regulation of a plasma membrane arabinogalactan protein epitope during development of the aerial parts of oilseed rape using the monoclonal antibody JIM8. The JIM8 epitope is expressed by the first cells of the embryo and by certain cells in the sexual organs of flowers. During embryogenesis, the JIM8 epitope ceases to be expressed by the embryo proper but is still found in the suspensor. During differentiation of the stamens and carpels, expression of the JIM8 epitope progresses from one cell type to another, ultimately specifying the endothecium and sperm cells, the nucellar epidermis, synergid cells, and the egg cell. This complex temporal sequence demonstrates rapid turnover of the JIM8 epitope. There is no direct evidence for any cell-inductive process in plant development. However, if cell-cell interactions exist in plants and participate in flower development, the JIM8 epitope may be a marker for one set of them.
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| 22. |
- Ringberg, Anita, et al.
(författare)
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Bilateral and multifocal breast carcinoma. A clinical and autopsy study with special emphasis on carcinoma in situ
- 1991
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Ingår i: European Journal of Surgical Oncology. - 1532-2157. ; 17:1, s. 20-29
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Tidskriftsartikel (refereegranskat)abstract
- Bilateral clinical breast carcinoma has been reported to appear in up to approximately 10% of patients with breast carcinoma. Increasing diagnostic activity has raised figures of bilaterality, mainly due to detection of lesions of the in situ type. Knowledge of the natural history of carcinoma in situ is incomplete and clinical implications are uncertain. In the present study bilateral lesions were analysed by extensive histological examination in the following groups of patients: (1) Forty-six women (median age 44 years) with clinical and mammographical unilateral invasive breast carcinoma, where the contralateral breast was removed at subcutaneous mastectomy (SCM) during the course of breast reconstruction, 24/46 (52%) had bilateral malignant lesions, four invasive carcinomas and 20 in situ carcinomas (two ductal carcinomas in situ /DCIS/, 15 lobular carcinomas in situ (LCIS), three both DCIS and LCIS). (2) Fifty-two women (median age 50 years) with a unilateral diagnosis of in situ carcinoma (32 DCIS, 16 LCIS, four both DCIS and LCIS), in whom both breasts were removed at SCM. 25/52 (48%) had bilateral malignant lesions, one invasive carcinoma, 24 in situ carcinomas (three DCIS, 18 LCIS, three both DCIS and LCIS). Twelve of 20 cases with LCIS (60%) were bilateral. Of 36 cases with DCIS, seven (19%) were bilateral. (3) The contralateral breast was removed at autopsy in 64 women previously unilaterally mastectomized (at median age 65) for invasive breast carcinoma. Fifteen of 64 (23%) had contralateral primary carcinoma at autopsy, four invasive carcinomas, 11 in situ carcinomas (six DCIS, five LCIS) and 8/64 (13%) had metastases in the breast. Multifocal malignant findings were also analysed in 47 SCM specimens after excisional biopsy for in situ carcinoma. In 35/47 (75%) further malignant lesions were present in spite of normal mammographic and clinical findings. Four were invasive and 31 had in situ lesions (16 DCIS, 10 LCIS, five both DCIS and LCIS): These findings may favour the hypothesis that some carcinomas in situ may remain silent or even regress. It is thus important to embark upon randomized trials to clarify the natural history of breast carcinoma in situ. Such a trial has been started in the southern region of Sweden.
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| 23. |
- Ringberg, Anita, et al.
(författare)
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Breast carcinoma in situ in 167 women--incidence, mode of presentation, therapy and follow-up
- 1991
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Ingår i: European Journal of Surgical Oncology. - 1532-2157. ; 17:5, s. 466-476
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Tidskriftsartikel (refereegranskat)abstract
- In the city of Malmo, in southern Sweden, 1693 women were diagnosed as having breast carcinoma during 1976 through 1984. Of these, 167 women had pure in situ breast carcinoma (9.9%). One hundred and thirty-two had ductal carcinoma in situ (DCIS) alone or in combination with lobular carcinoma in situ (LCIS), intracystic carcinoma and/or Paget's disease of the nipple. Thirty-three had pure LCIS and two had pure intracystic carcinomas. The incidence of breast carcinoma in situ (CIS) in women 20 years of age or older was 18.7 per 10(5) woman years with high rates of DCIS for all ages above 40, whereas a decline in incidence rate was seen for LCIS in the postmenopausal age groups. The ratio of DCIS to LCIS was 4:1. Of the 132 patients with DCIS, 46% were asymptomatic and were diagnosed by mammography, 35% presented with clinical symptoms, and 19% of the cases were incidental findings in breasts operated on for benign lesions. Mammography had been performed on all patients with DCIS and contributed to diagnosis in 75%. Sixty-one per cent of all DCIS lesions had microcalcifications suspicious for carcinoma. Eighty-nine of 132 patients with DCIS underwent fine-needle aspiration biopsy (FNAB) before surgical biopsy. FNAB was suspicious or diagnostic for carcinoma in 57/89 (64%). Of 33 cases with LCIS all but one were incidental findings. In one of 28 cases with LCIS examined by mammography there was suspicion of carcinoma. Sixteen per cent of the patients with DCIS were treated by a breast-conserving operation (BCO), the remaining patients by mastectomy (ME) (52%) or subcutaneous mastectomy (SCM) (33%) with immediate reconstruction. Thirty-three per cent of the patients with LCIS were treated by BCO, the remaining patients by ME (18%) or SCM (49%) with immediate reconstruction. Only one patient had radiotherapy postoperatively. In 60% of all CIS cases where an excisional biopsy had been performed there were further foci of CIS in the final ME/SCM specimen. After a median follow-up of 7 years for the DCIS group, three patients out of 21 treated by BCO had invasive carcinoma appearing ipsilaterally. They were alive and without symptoms of recurrent disease 2.5 to 6 years following further surgery. One patient treated by SCM died from generalized ductal breast carcinoma. In the LCIS group (median follow-up 8 years) one patient out of 11 had an invasive tubular carcinoma diagnosed 4 years after BCO. Eight years later she was alive and well after bilateral SCM.
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| 24. |
- Tilander, Åke, 1962-
(författare)
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Alternatives to Dechonchy's `Constants'
- 1991
-
Ingår i: The international journal for the psychology of religion. - Hillsdale, N.J. : Erlbaum. - 1050-8619 .- 1532-7582. ; 1:1, s. 23-26
-
Tidskriftsartikel (refereegranskat)
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| 25. |
- Tydén, Tanja, 1949-, et al.
(författare)
-
Swedish adolescents' knowledge of sexually transmitted diseases and their attitudes to the condom.
- 1991
-
Ingår i: Midwifery. - 0266-6138 .- 1532-3099. ; 7:1, s. 25-30
-
Tidskriftsartikel (refereegranskat)abstract
- In an attempt to assess the risk of AIDS infection in teenagers in Sweden a survey of adolescent sexual behaviour was conducted in Uppsala. Two hundred and nine students in the first form of an upper secondary school completed a questionnaire at the beginning of a lesson on family life. Half the female and 45% of the male students reported having had sexual intercourse. Forty per cent had not used contraception at their first intercourse and 23% reported no use of contraceptive at their most recent intercourse. The students considered that they had only a low risk of contracting a sexually transmitted disease. The use of condoms was relatively low and this has implications for the students' potential to contract a sexually transmitted disease.
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| 26. |
- Wingsle, Gunnar, et al.
(författare)
-
ISOLATION, PURIFICATION, AND SUBCELLULAR-LOCALIZATION OF ISOZYMES OF SUPEROXIDE-DISMUTASE FROM SCOTS PINE (PINUS-SYLVESTRIS L) NEEDLES
- 1991
-
Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 95:1, s. 21-28
-
Tidskriftsartikel (refereegranskat)abstract
- Two of four isozymes of superoxide dismutase (SOD) (EC 1.15.1.1) were purified from Scots pine (Pinus sylvestris L.) needles. One form was cytosolic (SOD-1) and the other was associated with chloroplasts (SOD-3). The holoenzyme molecular masses was estimated at approximately 35 kilodaltons by gel filtration. The subunit molecular weight of the dimeric enzymes was estimated to 16.5 kilodaltons (SOD-1) and 20.4 kilodaltons (SOD-3) on sodium dodecyl sulfatepolyacrylamide gels. The NH2-terminal sequence of the pine enzymes showed similarities to other purified superoxide dismutases located in the corresponding compartment. The cytosolic form revealed two additional amino acids at position 1 and 2 at the NH2-terminal. Both forms were cyanide- and hydrogenperoxide-sensitive and SOD-3 was found to contain approximately one copper atom per subunit, indicating that they belong to the cupro-zinc SODs. The isoelectric point was 4.9 and 4.5 for SOD-1 and SOD-3, respectively.
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| 27. |
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| 28. |
- Çakanlar, Aylin, 1991-, et al.
(författare)
-
How economic system justification shapes demand for peer-to-peer providers
- 2023
-
Ingår i: Journal of Consumer Pshychology. - : John Wiley & Sons. - 1057-7408 .- 1532-7663. ; 33:3, s. 602-612
-
Tidskriftsartikel (refereegranskat)abstract
- With the proliferation of peer-to-peer (P2P) exchanges in the marketplace, understanding which consumer factors drive demand for P2P providers is important. We examine the role of consumers' economic system justification (ESJ) beliefs (about the fairness of existing economic arrangements and outcomes), which, despite their growing salience in the marketplace, have been overlooked in extant P2P research. We show that high (vs. low) ESJ increases consumers' interest in purchasing from P2P providers because it heightens perceptions of these providers' entrepreneurial spirit. The effect emerges in the laboratory and in the field with measured and manipulated ESJ, and it is attenuated for traditional commercial providers. The findings offer novel insights and implications for practice and emerging research on P2P exchanges, system justification, and ideological consumption more broadly.
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| 29. |
- Galozy, Alexander, 1991-, et al.
(författare)
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Prediction and pattern analysis of medication refill adherence through electronic health records and dispensation data
- 2020
-
Ingår i: Journal of Biomedical Informatics: X. - New York, NY : Elsevier. - 2590-177X .- 1532-0464. ; 6-7
-
Tidskriftsartikel (refereegranskat)abstract
- Background and purposeLow adherence to medication in chronic disease patients leads to increased morbidity, mortality, and healthcare costs. The widespread adoption of electronic prescription and dispensation records allows a more comprehensive overview of medication utilization. In combination with electronic health records (EHR), such data provides new opportunities for identifying patients at risk of nonadherence and provide more targeted and effective interventions. The purpose of this article is to study the predictability of medication adherence for a cohort of hypertensive patients, focusing on healthcare utilization factors under various predictive scenarios. Furthermore, we discover common proportion of days covered patterns (PDC-patterns) for patients with index prescriptions and simulate medication-taking behaviours that might explain observed patterns.ProceduresWe predict refill adherence focusing on factors of healthcare utilization, such as visits, prescription information and demographics of patient and prescriber. We train models with machine learning algorithms, using four different data splits: stratified random, patient, temporal forward prediction with and without index patients. We extract frequent, two-year long PDC-patterns using K-means clustering and investigate five simple models of medication-taking that can generate such PDC-patterns.FindingsModel performance varies between data splits (AUC test set: 0.77–0.89). Including historical information increases the performance slightly in most cases (approx. 1–2% absolute AUC uplift). Models show low predictive performance (AUC test set: 0.56–0.66) on index-prescriptions and patients with sudden drops in PDC (Recall: 0.58–0.63). We find 21 distinct two-year PDC-patterns, ranging from good adherence to intermittent gaps and early discontinuation in the first or second year. Simulations show that observed PDC-patterns can only be explained by specific medication consumption behaviours.ConclusionsPrediction models developed using EHR exhibit bias towards patients with high healthcare utilization. Even though actual medication-taking is not observable, consumption patterns may not be as arbitrary, provided that medication refilling and consumption is linked. © 2020 The Authors. Published by Elsevier Inc.
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| 30. |
- Gorbach, Tetiana, 1991-, et al.
(författare)
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Contrasting Identifying Assumptions of Average Causal Effects : Robustness and Semiparametric Efficiency
- 2023
-
Ingår i: Journal of machine learning research. - : Microtome Publishing. - 1532-4435 .- 1533-7928. ; 24:197, s. 1-65
-
Tidskriftsartikel (refereegranskat)abstract
- Semiparametric inference on average causal effects from observational data is based on assumptions yielding identification of the effects. In practice, several distinct identifying assumptions may be plausible; an analyst has to make a delicate choice between these models. In this paper, we study three identifying assumptions based on the potential outcome framework: the back-door assumption, which uses pre-treatment covariates, the front-door assumption, which uses mediators, and the two-door assumption using pre-treatment covariates and mediators simultaneously. We provide the efficient influence functions and the corresponding semiparametric efficiency bounds that hold under these assumptions, and their combinations. We demonstrate that neither of the identification models provides uniformly the most efficient estimation and give conditions under which some bounds are lower than others. We show when semiparametric estimating equation estimators based on influence functions attain the bounds, and study the robustness of the estimators to misspecification of the nuisance models. The theory is complemented with simulation experiments on the finite sample behavior of the estimators. The results obtained are relevant for an analyst facing a choice between several plausible identifying assumptions and corresponding estimators. Our results show that this choice implies a trade-off between efficiency and robustness to misspecification of the nuisance models.
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| 31. |
- Hedlund, Jakob, 1991-, et al.
(författare)
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Student Nurse Anesthetists' and Supervisors' Perspectives of Learning in the Operating Room : An Integrative Review
- 2024
-
Ingår i: Journal of Perianesthesia Nursing. - : Elsevier. - 1089-9472 .- 1532-8473. ; 39:2, s. 303-310.e8
-
Forskningsöversikt (refereegranskat)abstract
- PURPOSE: The purpose of this review was to identify supporting and hindering factors for student nurse anesthetists' (SNAs') learning in the operating room during clinical practice, from students' and supervisors' perspectives.DESIGN: An integrative review.METHODS: Systematic searches were conducted in Medline, Cinahl, PsycInfo, and ERIC. Search terms were related to nurse anesthetist, education, operating room context, and clinical setting. Searches were performed at three points in time and in total 1,530 unique articles were identified. After screening using Covidence and using Joanna Briggs Institute appraisal tools, 34 articles remained. These were analyzed inductively using a constant comparison method.FINDINGS: Supporting factors include preparation before clinical practice, clearly stated expectations, a respectful relationship with the supervisor, daily planning and communication, and constructive feedback. Hindering factors include lack of time, disruptive behavior from supervisors or other team members, and environmental factors such as a high room temperature and noisy environment.CONCLUSIONS: SNAs' learning situation in the operating room resembles undergraduate nurses' learning during clinical practice. Educators and supervisors can take several actions to promote SNAs' learning. Further research is warranted on the effect of teamwork on SNAs' learning.
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| 32. |
- Larsson, Hanna, 1991, et al.
(författare)
-
“It’s a New Chapter Now”: Establishing Commitments in the Romantic Domain during Young Adulthood
- 2020
-
Ingår i: Identity. - : Informa UK Limited. - 1528-3488 .- 1532-706X. ; 20:1, s. 37-57
-
Tidskriftsartikel (refereegranskat)abstract
- This longitudinal study examines identity development in the domain of romantic relationships during young adulthood and what the process of establishing commitments without exploration in this domain involves. Identity status in the romantic relationships domain was assessed for 118 Swedish individuals at the ages of 29 and 33, using the Identity Status Interview. Identity diffusion was less common at age 33 than at age 29, whereas foreclosure, moratorium, and identity achievement were equally common at both ages. The majority of those assigned to identity diffusion at age 29 had transitioned to identity foreclosure by age 33. These nine participants were selected as a subsample for further analysis of the process of commitment-making, and changes in their identity narratives between age 29 (before establishing commitments) and age 33 (after establishing commitments) were examined using case-based thematic analysis. The results suggest that the commitment-making process involves changes in identity content, such as having more elaborate and positive views on romantic relationships, as well as changes related to identity processes, including narrating one’s experiences and views concerning romantic relationships in a more temporally integrated way.
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| 33. |
- Hansson, A., et al.
(författare)
-
The direction of human mesenchymal stem cells into the chondrogenic lineage is influenced by the features of hydrogel carriers
- 2017
-
Ingår i: Tissue and Cell. - : Elsevier BV. - 1532-3072 .- 0040-8166. ; 49:1, s. 35-44
-
Tidskriftsartikel (refereegranskat)abstract
- Low back pain is a major public health issue in the Western world, one main cause is believed to be intervertebral disc (IVD) degeneration. To halt/diminish IVD degeneration, cell therapy using different biomaterials e.g. hydrogels as cell carriers has been suggested. In this study, two different hydrogels were examined (in vitro) as potential cell carriers for human mesenchymal stem cells (hMSCs) intended for IVD transplantation. The aim was to investigate cell- survival and chondrogenic differentiation of hMSCs when cultured in hydrogels Puramatrix((R)) or Hydromatrix((R)) and potential effects of stimulation with growth hormone (GH). hMSCs/hydrogel cultures were investigated for cell-viability, attachment, gene expressionof chondrogenic markers SOX9, COL2A1, ACAN and accumulation of extracellular matrix (ECM). In both hydrogel types, hMSCs were viable for 28 days, expressed integrin beta 1 which indicates adhesion of hMSCs. Differentiation was observed into chondrocyte-like cells, in a higher extent in hMSCs/Hydromatrix((R)) cultures when compared to hMSCs/Puramatrix ((R)) hydrogel cultures. Gene expression analyses of chondrogenic markers verified results. hMSCs/hydrogel cultures stimulated with GH displayed no significant effects on chondrogenesis. In conclusion, both hydrogels, especially Hydromatrix((R)) was demonstrated as a promising cell carrier in vitro for hMSCs, when directed into chondrogenesis. This knowledge could be useful in biological approaches for regeneration of degenerated human IVDs.
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| 34. |
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| 35. |
- Melander, Nils, 1989-, et al.
(författare)
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Non-surgical patient characteristics best predict outcome after 6 months in patients surgically treated for chronic subdural haematoma
- 2023
-
Ingår i: Journal of clinical neuroscience. - : Elsevier. - 0967-5868 .- 1532-2653. ; 114, s. 151-157
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Chronic subdural haematoma (CSDH) is one of the most common conditions encountered in neurosurgical practice. After surgery, the patients often improve dramatically; but their long-term outcome is more uncertain. The purpose of this study was to investigate predictors of outcome 6 months after surgery.METHODS: Retrospective data were collected on patients in Orebro County, Sweden, who had undergone surgery for CSDH at the Orebro University Hospital between 2013 and 2019. The outcomes were defined as favourable or unfavourable in terms of the modified Rankin Scale (mRS). A favourable outcome was defined as either mRS 0-2 or an unchanged mRS score in patients scoring 3-5 before surgery. From the variables in the data collected, a multiple logistic regression model was constructed.RESULTS: The study comprised 180 patients, of whom 134 (74.4%) were male. Median age was 79.2 years (IQR 71.7-85.5), and 129 (71.7%) patients had a favourable outcome at 6 months. In the group with an unfavourable outcome, 18 (10%) had died and 33 (18.3%) had either lost their independence in daily living or become somewhat less independent. The final multiple logistic regression model consisted of pre-surgery variables only: age (OR 0.92, 95% CI 0.87-0.97), CRP (OR 0.96, 95% CI 0.94-0.99), GCS > 13 (OR 3.66, 95% CI 1.09-12.3), Hb (OR 1.03, 95% CI 1.00-1.05), and ASA score < 3 (OR 2.58, 95% CI 0.98-6.79). The whole model had an AUC of 0.88.CONCLUSION: CSDH requiring surgery is associated with high morbidity and mortality at 6 months after surgery. Age, CRP, GCS, Hb and ASA score on admission for surgery are the variables that best predicts outcome. This knowledge can help to identify the patients at greatest risk for an unfavourable outcome, who may need additional support from the health care system.UNSTRUCTURED ABSTRACT: Chronic subdural haematoma (CSDH) is one of the most common conditions encountered in neurosurgical practice. After surgery, the patients often improve dramatically; but their long-term outcome is more uncertain. The purpose of this study was to investigate predictors of outcome, in terms of the modified Rankin Scale (mRS), 6 months after surgery. The study comprised 180 patients, of whom 134 (74.4%) were male. Median age was 79.2 years (IQR 71.7-85.5), and 129 (71.7%) patients had a favourable outcome at 6 months. In the group with an unfavourable outcome, 18 (10%) had died and 33 (18.3%) had either lost their independence in daily living or become somewhat less independent. The final multiple logistic regression model consisted of pre-surgery variables only: age (OR 0.92, 95% CI 0.87-0.97), CRP (OR 0.96, 95% CI 0.94-0.99), GCS > 13 (OR 3.66, 95% CI 1.09-12.3), Hb (OR 1.03, 95% CI 1.00-1.05), and ASA score < 3 (OR 2.58, 95% CI 0.98-6.79). The whole model had an AUC of 0.88. In conclusion, CSDH requiring surgery is associated with high morbidity and mortality at 6 months after surgery. Age, CRP, GCS, Hb and ASA score on admission for surgery are the variables that best predicts outcome. This knowledge can help to identify the patients at greatest risk for an unfavourable outcome, who may need additional support from the health care system.
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| 36. |
- Ménard, Delphine, et al.
(författare)
-
Plant biomechanics and resilience to environmental changes are controlled by specific lignin chemistries in each vascular cell type and morphotype
- 2022
-
Ingår i: The Plant Cell. - : Oxford University Press. - 1040-4651 .- 1532-298X. ; 34:12, s. 4877-4896
-
Tidskriftsartikel (refereegranskat)abstract
- The biopolymer lignin is deposited in the cell walls of vascular cells and is essential for long-distance water conduction and structural support in plants. Different vascular cell types contain distinct and conserved lignin chemistries, each with specific aromatic and aliphatic substitutions. Yet, the biological role of this conserved and specific lignin chemistry in each cell type remains unclear. Here, we investigated the roles of this lignin biochemical specificity for cellular functions by producing single cell analyses for three cell morphotypes of tracheary elements, which all allow sap conduction but differ in their morphology. We determined that specific lignin chemistries accumulate in each cell type. Moreover, lignin accumulated dynamically, increasing in quantity and changing in composition, to alter the cell wall biomechanics during cell maturation. For similar aromatic substitutions, residues with alcohol aliphatic functions increased stiffness whereas aldehydes increased flexibility of the cell wall. Modifying this lignin biochemical specificity and the sequence of its formation impaired the cell wall biomechanics of each morphotype and consequently hindered sap conduction and drought recovery. Together, our results demonstrate that each sap-conducting vascular cell type distinctly controls their lignin biochemistry to adjust their biomechanics and hydraulic properties to face developmental and environmental constraints.
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| 37. |
- Boquist, Lennart, et al.
(författare)
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Ca2+ transport in isolated mouse liver mitochondria; role of reductive carboxylation and citrate?
- 1986
-
Ingår i: Cell Calcium. - : Elsevier. - 0143-4160 .- 1532-1991. ; 7:4, s. 275-282
-
Tidskriftsartikel (refereegranskat)abstract
- The uptake of Ca2+ in isolated mouse liver mitochondria respiring on succinate in the presence of rotenone and added Pi, was inhibited by dibucaine, fluorocitrate, p-hydroxymercuribenzoate (PMB), malonate, palmitoyl-CoA, succinyl-CoA and trifluoroperazine. The release of accumulated Ca2+ was stimulated by arsenite, malonate, PMB, palmitoyl-CoA and succinyl-CoA, whereas the release was inhibited by dibucaine, fluorocitrate, trifluoroperazine, and by oligomycin, especially in the presence of ADP. The pyridine nucleotides were oxidized in mitochondria incubated with PMB. The observations suggest a possible contributory role of reductive carboxylation for the uptake of Ca2+, and a possible role of citrate for the retention of Ca2+ in isolated mouse liver mitochondria.
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| 38. |
- Gustafsson, Mikael, et al.
(författare)
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A novel principle for quantitation of fast intracellular calcium changes using Fura-2 and a modified image processing system : applications in studies of neutrophil motility and phagocytosis
- 1992
-
Ingår i: Cell Calcium. - : Churchill Livingstone. - 0143-4160 .- 1532-1991. ; 13:8, s. 473-486
-
Tidskriftsartikel (refereegranskat)abstract
- A new principle is described for imaging intracellular free calcium [Ca2+]i changes in single, living cells utilizing the fluorescent probe Fura-2. It is based upon video color mixing in real time and allows high-speed visualization, at maximum image resolution, of [Ca2+]i changes without digital image ratioing. The epifluorescence images produced by 340 and 380 nm excitations are stored in two memory buffers of a personal computer-based image processing system. Two video signals are generated independently from each buffer and connected to the red and green inputs of a video display. An image is this way created, in which [Ca2+]i shows up as a specific hue, whereas changes in dye concentration, light intensity, cell thickness show up as variations in brightness of the imaged cells. The method has advantages over conventional ratio imaging, notably simplicity and speed, since no calculations are made. Yet it can be combined with traditional digital image processing. The imaging technique allows monitoring of [Ca2+]i changes in rapidly moving cells, like neutrophils. It is demonstrated that during random locomotion on serum-coated glass surfaces, [Ca2+]i levels appeared to oscillate and that the frequency of the oscillations are related to locomotive activity. Furthermore, in Ca2+ free medium, the cells continue to move and phagocytose in the presence of Ca2+ ionophore (ionomycin) and 2 mM EGTA. In the presence of 1 mM extracellular Ca2+, ionomycin-treated cells were not able to move or phagocytose.
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| 39. |
- Pakhtusova, Natalia, et al.
(författare)
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Cell-specific Ca2+ responses in glucose-stimulated single and aggregated ß-cells
- 2003
-
Ingår i: Cell Calcium. - : Elsevier ScienceDirect. - 0143-4160 .- 1532-1991. ; 34:2, s. 121-129
-
Tidskriftsartikel (refereegranskat)abstract
- A rise in the cytoplasmic calcium concentration ([Ca(2+)](i)) is a key event for insulin exocytosis. We have recently found that the 'early [Ca(2+)](i) response' in single ob/ob mouse beta-cells is reproduced during consecutive glucose stimulations. It, therefore, appears that the response pattern is a characteristic of the individual beta-cell. We have now investigated if a cell-specific [Ca(2+)](i) response is a general phenomenon in rodent beta-cells, and if it can be observed when cells are functionally coupled. With the use of the fura-2 technique, we have studied the 'early [Ca(2+)](i) response' in single dispersed beta-cells, in beta-cell clusters of different size and in intact islets from the ob/ob mouse during repeated glucose stimulation (20mM). beta-Cells from lean mouse and rat, and intact islets from lean mouse were also investigated. Significant correlations between the first and second stimulation were found for the parameters lag-time for Ca(2+) rise (calculated as the time from start of stimulation of the cell until the first value above an extrapolated baseline), nadir of initial lowering (difference between the baseline and lowest [Ca(2+)](i) value), and peak height (difference between baseline and the highest [Ca(2+)](i) value of the first calcium peak) in single dispersed beta-cells, in 'single beta-cell within a small cluster', in clusters of medium and large size, and in single dispersed beta-cells from lean mouse and rat. The lag-times for Ca(2+) rise and peak heights were correlated within the pairs of stimulation also in intact ob/ob islets. In summary, despite a large heterogeneity of the 'early [Ca(2+)](i) response' among individual cells, the lag-time for [Ca(2+)](i) rise, the nadir of initial lowering and the height of the first peak response can be identified as cell-specific markers in beta-cells.
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| 40. |
- Westerblad, H., et al.
(författare)
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Effects of ryanodine receptor agonist 4-chloro-m-cresol on myoplasmic free Ca2+ concentration and force of contraction in mouse skeletal muscle
- 1998
-
Ingår i: Cell Calcium. - 0143-4160 .- 1532-1991. ; 24:2, s. 105-115
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Tidskriftsartikel (refereegranskat)abstract
- In single mouse skeletal muscle fibers injected with fluorescent Ca2+ indicator Indo-1, 4-chloro-m-cresol (chlorocresol, 4-CmC) and its lipophilic analogue 4-chloro-3-ethylphenol (4-CEP) increased resting myoplasmic free [Ca2+] ([Ca2+]i) in a dose-dependent manner. In this regard, 4-CEP was more potent than 4-CmC and both were more potent than caffeine. High concentrations of 4-CmC (1 mM) or 4-CEP (500 microM) caused large and irreversible increase in resting [Ca2+]i leading to contracture. 4-CmC potentiated the [Ca2+]i increase and force of contraction induced by tetanic stimulation. Unlike caffeine, 4-CmC did not affect the activity of sarcoplasmic reticulum Ca2+ pump or the myofibrillar Ca2+ sensitivity. A low concentration of 4-CEP (20 microM) had no effect on resting [Ca2+]i on its own, but it enhanced the resting [Ca2+]i increase induced by caffeine and also potentiated the [Ca2+]i increase and contraction induced by tetanic stimulation. However, a relatively high concentration of 4-CEP (200 microM) inhibited tetanic stimulation-induced [Ca2+]i increase and contraction. Dantrolene, a muscle relaxant, inhibited 4-CmC-induced [Ca2+]i increase under resting conditions. However, when 4-CEP was applied in the presence of dantrolene, there was an exaggerated increase in [Ca2+]i. We conclude that 4-CmC and 4-CEP are potent agonists that can increase [Ca2+]i rapidly and reversibly by activating ryanodine receptors in situ in intact skeletal muscle fibers. These compounds, specially 4-CmC, may be useful for mechanistic and functional studies of ryanodine receptors and excitation-contraction coupling in skeletal muscles.
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| 41. |
- Aperia, Anita, et al.
(författare)
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Mending Fences : Na,K-ATPase signaling via Ca2+ in the maintenance of epithelium integrity
- 2020
-
Ingår i: Cell Calcium. - : Elsevier BV. - 0143-4160 .- 1532-1991. ; 88
-
Tidskriftsartikel (refereegranskat)abstract
- Na,K-ATPase is a ubiquitous multifunctional protein that acts both as an ion pump and as a signal transducer. The signaling function is activated by ouabain in non-toxic concentrations. In epithelial cells the ouabain-bound Na,K-ATPase connects with the inositol 1,4,5-trisphosphate receptor via a short linear motif to activate low frequency Ca2+ oscillations. Within a couple of minutes this ouabain mediated signal has resulted in phosphorylation or dephosphorylation of 2580 phospho-sites. Proteins that control cell proliferation and cell adhesion and calmodulin regulated proteins are enriched among the ouabain phosphor-regulated proteins. The inositol 1,4,5-trisphosphate receptor and the stromal interaction molecule, which are both essential for the initiation of Ca2+ oscillations, belong to the ouabain phosphor-regulated proteins. Downstream effects of the ouabain-evoked Ca2+ signal in epithelial cells include interference with the intrinsic mitochondrial apoptotic process and stimulation of embryonic growth processes. The dual function of Na,K-ATPase as an ion pump and a signal transducer is now well established and evaluation of the physiological and pathophysiological consequences of this universal signal emerges as an urgent topic for future studies.
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| 42. |
- Baczyk, D, et al.
(författare)
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Calcium signaling in placenta
- 2011
-
Ingår i: Cell calcium. - : Elsevier BV. - 1532-1991 .- 0143-4160. ; 49:5, s. 350-356
-
Tidskriftsartikel (refereegranskat)
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| 43. |
- Dyachok, Oleg, et al.
(författare)
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Ca2+-induced Ca2+ release by activation of inositol 1,4,5-trisphosphate receptors in primary pancreatic β-cells
- 2004
-
Ingår i: Cell Calcium. - : Elsevier BV. - 0143-4160 .- 1532-1991. ; 36:1, s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) inhibition on the cytoplasmic Ca2+ concentration ([Ca2+]i) was studied in primary insulin-releasing pancreatic β-cells isolated from mice, rats and human subjects as well as in clonal rat insulinoma INS-1 cells. In Ca2+-deficient medium the individual primary β-cells reacted to the SERCA inhibitor cyclopiazonic acid (CPA) with a slow rise of [Ca2+]i followed by an explosive transient elevation. The [Ca2+]i transients were preferentially observed at low intracellular concentrations of the Ca2+ indicator fura-2 and were unaffected by pre-treatment with 100 μM ryanodine. Whereas 20 mM caffeine had no effect on basal [Ca2+]i or the slow rise in response to CPA, it completely prevented the CPA-induced [Ca2+]i transients as well as inositol 1,4,5-trisphosphate-mediated [Ca2+]i transients in response to carbachol. In striking contrast to the primary β-cells, caffeine readily mobilized intracellular Ca2+ in INS-1 cells under identical conditions, and such mobilization was prevented by ryanodine pre-treatment. The results indicate that leakage of Ca2+ from the endoplasmic reticulum after SERCA inhibition is feedback-accelerated by Ca2+-induced Ca2+ release (CICR). In primary pancreatic β-cells this CICR is due to activation of inositol 1,4,5-trisphosphate receptors. CICR by ryanodine receptor activation may be restricted to clonal β-cells.
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| 44. |
- Finazzi, Giovanni, et al.
(författare)
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Ions channels/transporters and chloroplast regulation.
- 2015
-
Ingår i: Cell Calcium. - : Elsevier BV. - 0143-4160 .- 1532-1991. ; 58:1, s. 86-97
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Tidskriftsartikel (refereegranskat)abstract
- Ions play fundamental roles in all living cells and their gradients are often essential to fuel transports, to regulate enzyme activities and to transduce energy within and between cells. Their homeostasis is therefore an essential component of the cell metabolism. Ions must be imported from the extracellular matrix to their final subcellular compartments. Among them, the chloroplast is a particularly interesting example because there, ions not only modulate enzyme activities, but also mediate ATP synthesis and actively participate in the building of the photosynthetic structures by promoting membrane-membrane interaction. In this review, we first provide a comprehensive view of the different machineries involved in ion trafficking and homeostasis in the chloroplast, and then discuss peculiar functions exerted by ions in the frame of photochemical conversion of absorbed light energy.
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| 45. |
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| 46. |
- Hellman, Bo, et al.
(författare)
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Somatostatin promotes glucose generation of Ca2+ oscillations in pancreatic islets both in the absence and presence of tolbutamide
- 2018
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Ingår i: Cell Calcium. - : Elsevier BV. - 0143-4160 .- 1532-1991. ; 74, s. 35-42
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Tidskriftsartikel (refereegranskat)abstract
- Many cellular processes, including pulsatile release of insulin, are triggered by increase of cytoplasmic Ca2+. This study examines how somatostatin affects glucose generation of cytoplasmic Ca2+ oscillations in mouse islets in absence and presence of tolbutamide blockade of the K-ATP channels. Ca2+ was measured with dual wavelength microflurometry in isolated islets loaded with the indicator Fura-2. Rise of glucose from 3 to 20 mM evoked introductory lowering of Ca2+ prolonged by activation of somatostatin receptors. During continued superfusion exposure to somatostatin triggered oscillations mediated by periodic increase from the basal level (absence of tolbutamide) or by periodic interruption of an elevated level (presence of tolbutamide). In the latter situation the oscillations were transformed into sustained elevation by activation of muscarinic receptors (acetylcholine) or increase of cyclic AMP (IBMX, 8-bromo-cyclic AMP, forskolin). The observed effect of cyclic AMP raises the question whether high proportions of the glucagon-producing alpha-cells promote steady-state elevation of Ca2+. In support for this idea somatostatin was found to trigger glucose-induced Ca2+ oscillations essentially in small islets that contain very few alpha-cells. The results indicate that somatostatin promotes glucose generation of Ca2+ oscillations with similar characteristics both in the absence and presence of functional K-ATP channels.
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| 47. |
- Hermann, Stefan, et al.
(författare)
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Calcium regulation of basic helix-loop-helix transcription factors
- 1998
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Ingår i: Cell Calcium. - : Elsevier. - 0143-4160 .- 1532-1991. ; 23:2-3, s. 135-142
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Tidskriftsartikel (refereegranskat)abstract
- The basic helix-loop-helix (bHLH) family of transcription factors is essential for numerous developmental and growth control processes. The regulation of bHLH proteins occurs at many levels, including tissue specific expression, differential oligomerization and DNA binding specificities, interaction with negatively acting HLH proteins and post-translational modifications. This review focuses on what is emerging as another level of bHLH protein regulation, calcium regulation through interaction with Ca2+ loaded calmodulin and S-100 proteins. The mechanism and implications of these Ca2+ regulated interactions are discussed.
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| 48. |
- Karlsson, Jennie, 1979, et al.
(författare)
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The FPR2-specific ligand MMK-1 activates the neutrophil NADPH-oxidase, but triggers no unique pathway for opening of plasma membrane calcium channels.
- 2009
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Ingår i: Cell calcium. - : Elsevier BV. - 1532-1991 .- 0143-4160. ; 45:5, s. 431-8
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Tidskriftsartikel (refereegranskat)abstract
- Human neutrophils express formyl peptide receptor 1 and 2 (FPR1 and FPR2), two highly homologous G-protein-coupled cell surface receptors important for the cellular recognition of chemotactic peptides. They share many functional as well as signal transduction features, but some fundamental differences have been described. One such difference was recently presented when the FPR2-specific ligand MMK-1 was shown to trigger a unique signal in neutrophils [S. Partida-Sanchez, P. Iribarren, M.E. Moreno-Garcia, et al., Chemotaxis and calcium responses of phagocytes to formyl peptide receptor ligands is differentially regulated by cyclic ADP ribose, J. Immunol. 172 (2004) 1896-1906]. This signal bypassed the emptying of the intracellular calcium stores, a route normally used to open the store-operated calcium channels present in the plasma membrane of neutrophils. Instead, the binding of MMK-1 to FPR2 was shown to trigger a direct opening of the plasma membrane channels. In this report, we add MMK-1 to a large number of FPR2 ligands that activate the neutrophil superoxide-generating NADPH-oxidase. In contrast to earlier findings we show that the transient rise in intracellular free calcium induced by MMK-1 involves both a release of calcium from intracellular stores and an opening of channels in the plasma membrane. The same pattern was obtained with another characterized FPR2 ligand, WKYMVM, and it is also obvious that the two formyl peptide receptor family members trigger the same type of calcium response in human neutrophils.
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| 49. |
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| 50. |
- Lundqvist-Gustafsson, Helen, 1966-, et al.
(författare)
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Dynamic Ca2+ changes in neutrophil phagosomes. A source for intracellular Ca2+ during phagolysosome formation?
- 2000
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Ingår i: Cell Calcium. - : Elsevier BV. - 0143-4160 .- 1532-1991. ; 27:6, s. 353-362
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Tidskriftsartikel (refereegranskat)abstract
- An increase in cytosolic Ca2+ concentration periphagosomally is critical for phagolysosomal formation and neutrophil elimination of microbes. The Ca2+ increase could be achieved through release of Ca2+ from mobilized intracellular stores. Alternatively, Ca2+ that passively enter the phagosome during phagocytosis could be provided by the phagosome. Intraphagosomal Ca2+ changes in single human neutrophils was measured during phagocytosis of serum opsonized Fura-2-conjugated zymosan particles, using a digital image processing system for microspectrofluorometry. A decrease in phagosomal Ca2+ down to nanomolar concentrations was seen within minutes following phagosomal closure. Blockage of plasma membrane Ca2+ channels by econazole abolished this decrease. The fluorescence properties of Fura-2 zymosan were retained after phagocytosis and stable to pH changes, reactive oxygen species, and proteolytic enzymes. We suggest that Ca2+ ions present in the phagosome enter the cell cytosol through Ca2+ channels in the phagosomal membrane, achieving a localized Ca2+ rise that is important for phagosome processing.
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