| 1. |
|
|
| 2. |
- Björkqvist, Maria, et al.
(författare)
-
Somatostatin, misoprostol and galanin inhibit gastrin- and PACAP-stimulated secretion of histamine and pancreastatin from ECL cells by blocking specific Ca(2+) channels.
- 2005
-
Ingår i: Regulatory Peptides. - : Elsevier BV. - 1873-1686 .- 0167-0115. ; 130:1-2, s. 81-90
-
Tidskriftsartikel (refereegranskat)abstract
- The oxyntic mucosa is rich in ECL cells. They secrete histamine and chromogranin A-derived peptides, such as pancreastatin, in response to gastrin and pituitary adenylate cyclase-activating peptide (PACAP). Secretion is initiated by Ca2+ entry. While gastrin stimulates secretion by opening L-type and N-type Ca2+ channels, PACAP stimulates secretion by activating L-type and receptor-operated Ca2+ channels. Somatostatin, galanin and prostaglandin E2 (PGE2) inhibit gastrin- and PACAP-stimulated secretion from the ECL cells. In the present study, somatostatin and the PGE2 congener misoprostol inhibited gastrin- and PACAP-stimulated secretion 100%, while galanin inhibited at most 60–65%. Bay K 8644, a specific activator of L-type Ca2+ channels, stimulated ECL-cell secretion, an effect that was inhibited equally effectively by somatostatin, misoprostol and galanin (75–80% inhibition). Pretreatment with pertussis toxin, that inactivates inhibitory G-proteins, prevented all three agents from inhibiting stimulated secretion (regardless of the stimulus). Pretreatment with nifedipine (10 μM), an L-type Ca2+ channel blocker, reduced PACAP-evoked pancreastatin secretion by 50–60%, gastrin-evoked secretion by not, vert, similar 80% and abolished the response to Bay K 8644. The nifedipine-resistant response to PACAP was abolished by somatostatin and misoprostol but not by galanin. Gastrin and PACAP raised the intracellular Ca2+ concentration in a biphasic manner, believed to reflect mobilization of internal Ca2+ followed by Ca2+ entry. Somatostatin and misoprostol blocked Ca2+ entry (and histamine and pancreastatin secretion) but not mobilization of internal Ca2+. The present observations on isolated ECL cells suggest that Ca2+ entry rather than mobilization of internal Ca2+ triggers exocytosis, that gastrin and PACAP activate different (but over-lapping) Ca2+ channels, that somatostatin, misoprostol and galanin interact with inhibitory G-proteins to block Ca2+ entry via L-type Ca2+ channels, and that somatostatin and misoprostol (but not galanin) in addition block N-type and/or receptor-operated Ca2+ channels.
|
|
| 3. |
- Borgström, Magnus, et al.
(författare)
-
Fabrication and characterization of AlP-GaP core-shell nanowires
- 2011
-
Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248. ; 324:1, s. 290-295
-
Tidskriftsartikel (refereegranskat)abstract
- We report on the particle assisted synthesis of core-shell AlP-GaP nanowires by use of metal-organic vapor phase epitaxy. The core-shell approach is chosen such as to stabilize the AlP which is highly sensitive to water. The nanowires were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. These nanowires have an indirect band-gap and form a type II staggered heterojunction. By designed capping of the AlP cores by GaP, we find the nanowires to be stable for more than a year. (C) 2011 Elsevier B.V. All rights reserved.
|
|
| 4. |
- Chen, Jianing, et al.
(författare)
-
Probing Strain in Bent Semiconductor Nanowires with Raman Spectroscopy.
- 2010
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 10:4, s. 1280-1286
-
Tidskriftsartikel (refereegranskat)abstract
- We present a noninvasive optical method to determine the local strain in individual semiconductor nanowires. InP nanowires were intentionally bent with an atomic force microscope and variations in the optical phonon frequency along the wires were mapped using Raman spectroscopy. Sections of the nanowires with a high curvature showed significantly broadened phonon lines. These observations together with deformation potential theory show that compressive and tensile strain inside the nanowires is the physical origin of the observed phonon energy variations.
|
|
| 5. |
|
|
| 6. |
- Florentzson, Malin, et al.
(författare)
-
Low gastric acid and high plasma gastrin in high-anxiety Wistar Kyoto rats
- 2009
-
Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 44:4, s. 401-407
-
Tidskriftsartikel (refereegranskat)abstract
- Objective. Wistar Kyoto (WKY) rats are more susceptible to stress-evoked ulcerations than Sprague-Dawley (SPD) rats. We have already demonstrated that gastrin cells are more active and ghrelin cells less active in WKY rats than in SPD rats. The purpose of this study was to compare endocrine cell activity and gastric acid output in WKY and SPD rats. Material and methods. Gastric acid output was determined in conscious rats with gastric fistula. Plasma gastrin and ghrelin levels were measured after an overnight fast. Acid secretagogues (gastrin, histamine and carbachol) were given by continuous subcutaneous infusion. Results. The volume of gastric juice, and the acidity and acid output were all significantly lower (p 0.05) in fasted WKY rats than in fasted SPD rats. Gastrin evoked a 4-fold (p 0.01) and 3-fold (p 0.05) increase in gastric acid output in SPD rats and WKY rats, respectively. Histamine raised the acid output 1.6-fold in SPD rats (p=0.06) and 3-fold in WKY rats (p 0.05), while carbachol failed to affect the acid output (weak increase, p 0.05). Fasting plasma ghrelin levels were 2-fold higher in SPD rats than in WKY rats (p 0.01) while fasting gastrin levels were 10-fold higher in WKY rats than in SPD rats (p 0.05). Neither the parietal-cell density nor the oxyntic mucosal thickness differed between the two strains. Conclusions. The results of the present study suggest that a high gastrin cell activity in WKY rats is secondary to a low gastric acidity. Whether the high gastrin cell activity is linked to susceptibility to stress ulcer in WKY rats warrants further investigation.
|
|
| 7. |
- Grundemar, L, et al.
(författare)
-
Neuropeptide Y : prejunctional inhibition of vagally induced contractions in the guinea pig trachea
- 1988
-
Ingår i: Regulatory Peptides. - : Elsevier BV. - 0167-0115. ; 23:3, s. 309-313
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of neuropeptide Y (NPY) on the contractile response to vagus nerve stimulation at different frequencies was studied in an isolated tracheal tube preparation from guinea pig. NPY had no effect on basal smooth muscle tension or on the contractile effect of carbachol, but inhibited vagally induced contractions in a concentration-dependent manner with a greater inhibition at low frequencies than at high. We suggest that the effect is exerted prejunctionally.
|
|
| 8. |
|
|
| 9. |
- Holm, Jonas, et al.
(författare)
-
EuroSCORE II and NT-proBNP for risk evaluation : an observational longitudinal study in patients undergoing CABG
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND: Postoperative heart failure remains the major cause of death after cardiac surgery. As NT-proBNP is a predictor for postoperative heart failure, the aim was to evaluate if preoperative NT-proBNP could provide additional prognostic information to the recently launched EuroSCORE II.METHODS: 365 patients with acute coronary syndrome (ACS) undergoing isolated CABG were studied prospectively. Preoperative NT-proBNP and EuroSCORE II were evaluated with regard to severe circulatory failure postoperatively according to prespecified criteria. To assess what clinical outcomes are indicated by NT-proBNP levels in different risk categories, the patients were stratified according to EuroSCORE II. Based on Reciever Operating Chracateristics (ROC) analysis these cohorts were assessed with regard to preoperative NT-proBNP below or above 1028 ng/L. Follow-up time averaged 4.4 ± 0.7 years.RESULTS: Preoperative NT-proBNP ≥ 1028 ng/L (OR 9.9, 95%CI 1.01-98.9;p=0.049) and EuroSCORE II (OR 1.24, 95%CI 1.06-1.46;p=0.008) independently predicted severe circulatory failure postoperatively. In intermediate risk patients (EuroSCORE II 2.0 – 10.0) NT-proBNP ≥ 1028 ng/L was associated with a higher incidence of severe circulatory failure (6.6% vs 0%;p=0.007), renal failure (14.8% vs 5.4%;p=0.03), stroke (6.6 % vs 0.7 %;p=0.03) , longer ICU stay (37±35 vs 27±38 hours; p=0.002) and worse long-term survival.CONCLUSIONS: Combining EuroSCORE II and preoperative NT-proBNP appears to improve risk prediction with regard to severe circulatory failure after isolated CABG for ACS. NTproBNP may be particularly useful in patients at intermediate risk according to EuroSCORE II.
|
|
| 10. |
- Holm, Jonas, 1971-
(författare)
-
Markers of hemodynamic state and heart failure as predictors for outcome in cardiac surgery : with special reference to mixed venous oxygen saturation and natriuretic peptides
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Postoperative heart failure or low cardiac output syndrome is the major cause for morbidity and mortality in cardiac surgery. Unfortunately commonly used methods to assess hemodynamic state and heart failure are not well documented with regard to outcome. The aim for this dissertation was to study the predictive values of postoperative Mixed Venous Oxygen saturation (SvO2) and preoperative NT-proBNP for outcomes related to postoperative heart failure.SvO2 was studied retrospectively in two cohorts of patients, one cohort operated with isolated Aortic Valve Replacement (AVR) for aortic stenosis, (n=396) and one operated with isolated Coronary Artery Bypass Grafting (CABG), (n=2755). SvO2 measured early after surgery, on admission to the intensive care unit (ICU), predicted postoperative morbidity and mortality. Our results suggest that, on admission to ICU SvO2 < 55 - 60% after AVR and SvO2 < 60% after CABG merits increased attention.Preoperative NT-proBNP was studied in a cohort of patients with acute coronary syndrome (ACS) undergoing CABG with or without concomitant procedure. These patients (n=383) were included prospectively and evaluated with regard to mortality and severe circulatory failure postoperatively by an end-points committee blinded to NT-proBNP results. Preoperative NT-proBNP ≥ 1028 ng/L independently predicted increased risk for severe circulatory failure postoperatively in patients with ACS undergoing isolated CABG. Preoperative NT-proBNP provided additional prognostic information to EuroSCORE II in this cohort, particularly in patients at intermediate risk. Preoperative NT-proBNP appears to be markedly higher in patients having CABG with concomitant procedures than in patients undergoing isolated CABG. Further studies are warranted to identify preoperative NTproBNP risk thresholds for different heart conditions and surgery-specific cohorts.In conclusion this dissertation shows that:Postoperative SvO2 on admission to ICU is a prognostic marker for morbidity and mortality after AVR and CABG.Preoperative NT-proBNP ≥ 1028 ng/L independently predicts severe circulatory failure postoperatively in patients undergoing isolated CABG and provides additional prognostic information to EuroSCORE II.The high negative predictive value of the identified cutoff levels for preoperative NTproBNP and postoperative SvO2 could be useful for pre and postoperative decisionmaking.
|
|
