| 1. |
- Pakhtusova, Natalia, et al.
(författare)
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Cell-specific Ca2+ responses in glucose-stimulated single and aggregated ß-cells
- 2003
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Ingår i: Cell Calcium. - : Elsevier ScienceDirect. - 0143-4160 .- 1532-1991. ; 34:2, s. 121-129
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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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| 2. |
- 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
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Ingår i: Cell Calcium. - : Elsevier BV. - 0143-4160 .- 1532-1991. ; 36:1, s. 1-9
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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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| 3. |
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| 4. |
- 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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| 5. |
- Åkerman, Karl, et al.
(författare)
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Ca2+-Dependent Potentiation of Muscarinic Receptor-Mediated Ca2+ Elevation
- 2004
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Ingår i: Cell Calcium. - : Elsevier BV. - 0143-4160 .- 1532-1991. ; 36:5, s. 397-408
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Tidskriftsartikel (refereegranskat)abstract
- Muscarinic receptor-mediated increases in Ca(2+) in SH-SY5Y neuroblastoma cells consist of an initial fast and transient phase followed by a sustained phase. Activation of voltage-gated Ca(2+) channels prior to muscarinic stimulation resulted in a several-fold potentiation of the fast phase. Unlike the muscarinic response under control conditions, this potentiated elevation of intracellular Ca(2+) was to a large extent dependent on extracellular Ca(2+). In potentiated cells, muscarinic stimulation also activated a rapid Mn(2+) entry. By using known organic and inorganic blockers of cation channels, this influx pathway was easily separated from the known Ca(2+) influx pathways, the store-operated pathway and the voltage-gated Ca(2+) channels. In addition to the Ca(2+) influx, both IP(3) production and Ca(2+) release were also enhanced during the potentiated response. The results suggest that a small increase in intracellular Ca(2+) amplifies the muscarinic Ca(2+) response at several stages, most notably by unravelling an apparently novel receptor-activated influx pathway.
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| 6. |
- Wang, XP, et al.
(författare)
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Evapotranspiration of Artemisia ordosica vegetation in stabilized arid desert dune in Shapotou, China
- 2004
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Ingår i: Arid Land Research and Management. - : Informa UK Limited. - 1532-4982 .- 1532-4990. ; 18:1, s. 63-76
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Tidskriftsartikel (refereegranskat)abstract
- More than 40 years of revegetation using mainly Artemisia ordosica, Hedysarum scoparium, and Caragana korshinskii at Shapotou Desert Experimental Research Station near Lanzhou has established a dwarf-shrub and herbaceous cover on the stabilized sand dunes. The evapotranspiration (ET) of the xerophyte dwarf-shrub A. ordosica plant vegetation was measured by the autoweighing lysimeter method during the growing seasons from 1990 to 1995, and 2002 on the southeast edge of the Tengger Desert at Shapotou, China. The study showed that the average ET rates were 0.88 mm d(-1), and they varied from 0.6 mm d(-1) to 1.31 mm d(-1) during the 7-year experimental period from 1990 to 1995, and 2002. The ratios of ET/Precipitation (P) varied from 69.8% to 120.9% with an average of 90.9%. The higher ET/P value in 1991 was associated with the properties of intra year distribution of rainfall events, and resulted in soil moisture depletion. The correlation between the accumulative P and the accumulative ET was quite high. For the years 1990, 1993, and 1995, the relationship between the accumulative ET and the accumulative P had a closed linear relationship, resulting from the higher intensity of monthly P exceeding 40% of the overall P during the growing season. Whatever the variation in the monthly P, statistics showed that the relationship between the accumulative P and ET could be expressed as an equation, ET=0.8003 P+5.8914, with a correlation coefficient of R-2=0.9035. Results suggest that in areas similar to Shapotou it is practical to establish an artificial protection belt using xerophytic shrubs.
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| 7. |
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| 8. |
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| 9. |
- Soloviev, A, et al.
(författare)
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Nitric oxide relaxes rat tail artery smooth muscle by cyclic GMP-independent decrease in calcium sensitivity of myofilaments
- 2004
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Ingår i: Cell Calcium. - : Elsevier BV. - 0143-4160. ; 36:2, s. 165-173
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Tidskriftsartikel (refereegranskat)abstract
- The effects of authentic nitric oxide (NO, 10(-6) M) and NO-donors such as sodium nitroprusside (SNP, 10(-5) M) and glyceryl trinitrate (GTN, 10(-4) M) on contractile force and free intracellular calcium level ([Ca2+],) were studied on precontracted with high potassium chloride (KCI, 70 mM) isolated rings of rat tail artery. The sensitivity of contractile myofilaments to Ca2+ was measured using chemically permeabilized (alpha-toxin, beta-escin, Triton X-100) vascular rings. [Ca2+](i) and contractile activity were measured simultaneously. The relationship of [Ca2+](i) and tension developed was studied in endothelium-denuded rings and controlled calcium response was evaluated in both endothelium-denuded and permeabilized vascular rings. Both authentic NO and NO-donors decreased [Ca2+](i) and high potassium-induced tension with a different time course. Inhibitor of soluble guanylyl cyclase (sGC) LY83583 (10(-5) M) did not affect SNP-induced relaxation whereas the other sGC inhibitor ODQ (10(-6) M) attenuated SNP-induced relaxation. Both inhibitors had no effect on NO- and SNP-induced reduction in [Ca2+](i). On the contrary, GTN induced neither relaxation nor decrease in [Ca2+](i) on application of both LY83583 and ODQ. Tail artery rings permeabilized with alpha-toxin, beta-escin, but not with Triton X-100 were relaxed by authentic NO and NO-donors, but to a less extent than non-permeabilized rings. Dithioerythritol (DTE, 5 x 10(-3) M) that maintains sulfhydryl (SH) groups in reduced state preventing their nitrosylation attenuated NO-induced relaxation in both non-permeabilized and permeabilized tail artery rings. The cyclic heptapeptide mycrocystin-LR (MC-LR) (10(-5) M), an inhibitor of type I and 2A phosphatases, induced sustained increase in tension of beta-escin permeabilized rings in low Ca2+ (10(-8) M) solution. The tension was not affected by authentic NO and SNP. We conclude that authentic NO and SNP relax rat tail artery smooth muscle (SM) in the presence of inhibitors of sGC via cyclic guanosine monophosphate (cGMP)- independent pathway, whereas relaxation induced by GTN is inhibited. The data demonstrate that cGMP-dependent pathway in vascular smooth muscle is ubiquitous, but not the only way of relaxation induced by NO. NO can modulate vascular tone directly by reducing sensitivity of contractile myofilaments to [Ca2+](i) and may involve activation of protein phosphatase(s). (C) 2004 Elsevier Ltd. All rights reserved.
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| 10. |
- Jacobson, L, et al.
(författare)
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The economic impact of asthma and chronic obstructive pulmonary disease (COPD) in Sweden in 1980 and 1991
- 2000
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Ingår i: Respiratory Medicine. - : Elsevier BV. - 1532-3064 .- 0954-6111. ; 94:3, s. 247-255
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Tidskriftsartikel (refereegranskat)abstract
- This study was carried out to estimate the direct and indirect costs associated with asthma and chronic obstructive pulmonary disease (COPD) in Sweden in 1980 and 1991, and to identify trends in the use of outpatient care, drugs and inpatient care, and the development of temporary morbidity, permanent disability and mortality for asthma and COPD. Routinely published administrative and population data were used to estimate the costs of asthma and COPD, and these figures were compared to corresponding estimates and trends for all respiratory diseases as well as for all diseases. Asthma and COPD each accounted for about SEK 3 billion, together roughly 2% of the economic cost of all diseases. Although the total costs associated with each disease were similar, the distribution of the different cost components and changes in each component over time differed. During the 1980s, the cost of drugs and out-patient care increased for both diseases. The cost of inpatient care for asthma decreased, whereas that for COPD increased. This study shows that asthma therapy has changed from inpatient to ambulatory care in Sweden, while the treatment of COPD to a higher degree still is based on inpatient care.
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| 11. |
- Fridenfalk, Mikael, et al.
(författare)
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Design and validation of a universal 6D seam tracking system in robotic welding based on laser scanning
- 2003
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Ingår i: Industrial Robot. - : Emerald. - 0143-991X. ; 30:5, s. 437-448
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the design and validation of a universal 6D seam tracking system that reduces the need of accurate robot trajectory programming and geometrical databases in robotic laser scanning. The 6D seam tracking system was developed in the flexible unified simulation environment, integrating software prototyping with mechanical virtual prototyping, based on physical experiments, The validation experiments showed that this system was both robust and reliable and should be able to manage a radius of curvature less than 200 mm. In the pre-scanning mode, a radius of curvature down to 2 mm was managed for pipe intersections an: 3 scans/mm, using a laser scanner with an accuracy of 0.015 mm.
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| 12. |
- Darelid, Johan, 1950-, et al.
(författare)
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Control of nosocomial Legionnaires' disease by keeping the circulating hot water temperature above 55°C : experience from a 10-year surveillance programme in a district general hospital
- 2002
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Ingår i: Journal of Hospital Infection. - : Elsevier BV. - 0195-6701 .- 1532-2939. ; 50:3, s. 213-219
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Tidskriftsartikel (refereegranskat)abstract
- After a nosocomial outbreak of Legionnaires' disease in a 450-bed district general hospital in 1991, the circulating hot water temperature was kept above 55°C as the sole control measure. From 1991 to 2000, all cases of nosocomial pneumonia were clinically monitored and tested for Legionella pneumophila serogroup 1 by serology or urinary antigen detection. Water samples from peripheral tap sites were cultured for Legionella spp. twice a year. An infection with L. pneumophila serogroup 1 was diagnosed in four out of 366 (1.1%) patients treated for nosocomial pneumonia, representing one case per 26 000 admissions. All patients were cured without complications. L. pneumophila serogroup 1 was isolated in 30 of 251 (12%) cultured hospital water samples during the monitoring period. We conclude that control of nosocomial Legionnaires' disease in a primary referral hospital is possible by keeping the circulating hospital hot water temperature above 55°C, together with careful clinical surveillance. Complete eradication of Legionella spp. from the hot water system does not seem necessary.
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| 13. |
- Lannefors, Louise, et al.
(författare)
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Demographic transition of the Swedish cystic fibrosis community--results of modern care.
- 2002
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Ingår i: Respiratory Medicine. - : Elsevier BV. - 1532-3064 .- 0954-6111. ; 96:9, s. 681-685
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Tidskriftsartikel (refereegranskat)abstract
- Assessing the results of modern cystic fibrosis (CF)-care and estimating the future population and its demography is important to evaluate the treatment regimens and to calculate the future needs of health-care resources.This paper updates previous incidence calculations. It assesses the results of modern CF-care in terms of survival and changing demography in Sweden. The incidence of CF in Sweden was calculated as 1/5600 live-births. Of the CF-population alive in 1999, 45% were > or = 18 years old. The mean annual mortality rate since 1991 was 0.9% (+/-0.4) and the median age at death 26 years (range 0-72). Of those born > or = 1991, 95% were estimated to survive their 25th birthday. The incidence of CF in Sweden is low. Modern CF-care in Sweden shows good results. The CF-population is growing rapidly and the adult part of the population will soon be larger than the paediatric. Continuously adapted resources are required to assure the future treatment quality especially for the growing adult CF-population.
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| 14. |
- Lundberg, Owe, et al.
(författare)
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Wound recurrences from gallbladder cancer after open cholecystectomy
- 2000
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Ingår i: Surgery. - : Elsevier BV. - 0039-6060 .- 1532-7361. ; 127:3, s. 296-300
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Reports of port site recurrences from gallbladder cancer after laparoscopic cholecystectomy have raised considerable concern as to whether the laparoscopic technique implies an increased risk of metastatic disease. In a previous study of gallbladder cancer and laparoscopic cholecystectomy, we reported a frequency of 16% port site metastases. The purpose of the present study was to determine the frequency of wound metastases from gallbladder cancer after open cholecystectomy. METHODS: The registers from the Swedish Oncological Centers and the National Board of Health and Welfare were checked for reported cases of gallbladder cancer and surgical classification codes for open cholecystectomy from 1991 to 1994. The study included all 8 university and 24 county hospitals in Sweden. The files from all patients with gallbladder cancer who had an open cholecystectomy were retrospectively reviewed. RESULTS: The study included 270 patients who had a cholecystectomy, of which 215 were classified as open and 55 as laparoscopic. Of the 215 patients, 11 patients were excluded because of an incorrect or deficient histopathologic or surgical classification. In 186 patients (91%), sufficient data were obtained for follow-up. Twelve patients (6.5%) had wound metastases from their gallbladder cancer. All patients with wound metastases died with a median survival of 10 months (range, 3 to 65 months). CONCLUSIONS: Wound metastases from gallbladder cancer after open cholecystectomy may be more common than previously assumed.
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| 15. |
- Brattberg, Gunilla
(författare)
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Do pain problems in young school children persist into early adulthood? : A 13-year follow-up
- 2004
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Ingår i: European Journal of Pain. - : Elsevier. - 1090-3801 .- 1532-2149. ; 8:3, s. 187-199
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Tidskriftsartikel (refereegranskat)abstract
- Design. In a longitudinal study, 335 children ages 8, 11 and 14, first studied in 1989 were followed-up on two occasions in 1991 and 2002. The subjects filled in questionnaires on pain, the first two times in school, the last as a postal survey. Purposes. To determine if headache and back pain during the school years were transitory or if they grew into pain problems in adulthood; to determine predictors of pain. Results. In the 2002 study, 59% of the women and 39% of the men reported pain at 21, 24 and 27 years. A total of 68 (52 women, 16 men) or 20% of the subjects reported pain symptoms in all three studies. The cumulative incidence rate for the presence of pain in the cohort studied was 31% for 1989–2002 and 43% for 1991–2002. Four of the 10 individuals with pain also reported signs of stress. Three predictors were found: reported back pain in 8–14-year-olds (p<0.0001); reported headaches once a week or more in the same age group (p<0.0001); and a positive response in the ages 10–16 to the question: “Do you often feel nervous?” (OR=2.1, 95% CI 1.3–3.4). When adjusted for age, sex and all psychosocial risk determinants studied in multiple logistic regression, a positive answer to this question was a significant predictor of pain in young adulthood. A positive response by the 10–16-year-olds to “Do you find it difficult to describe your feelings?” was a predictor of pathological anxiety in early adulthood, but stress perceived in childhood/adolescence did not predict future pain or stress. Conclusions. Since pain reports in childhood and early adolescence seem to be associated with the report of pain in early adulthood, more attention should be given to the way ill-health is managed in adolescence in this vulnerable group.
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