| 181. |
- Salehi, S Albert, et al.
(författare)
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The pseudotetrasaccharide acarbose inhibits pancreatic islet glucan-1,4-alpha-glucosidase activity in parallel with a suppressive action on glucose-induced insulin release
- 1995
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 44:7, s. 830-836
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Tidskriftsartikel (refereegranskat)abstract
- The pseudotetrasaccharide acarbose, previously known as a potent inhibitor of intestinal alpha-glucoside hydrolases, was investigated with regard to its influence on islet lysosomal enzyme activities and the insulin secretory processes. We observed that acarbose was a potent inhibitor of mouse islet lysosomal acid glucan-1,4-alpha-glucosidase activity, EC50 approximately 5 mumol/l, as well as of acid alpha-glucosidase activity. In contrast, acarbose did not influence other lysosomal enzyme activities such as acid phosphatase and N-acetyl-beta-D-glucosaminidase. Neutral alpha-glucosidase (endoplasmic reticulum) was only moderately inhibited in homogenate and was unaffected in intact islets. Incubation of isolated mouse islets with acarbose revealed that the pseudotetrasaccharide was a strong inhibitor of glucose-induced insulin secretion, EC50 approximately 500 nmol/l, and a significant inhibition was already observed at a concentration of acarbose as low as 100 nmol/l. The acarbose analogue maltotetrose did not influence either glucose-induced insulin release or islet lysosomal enzyme activities. Further, acarbose as well as two other alpha-glucoside hydrolase inhibitors, the deoxynojirimycin derivatives miglitol and emiglitate, did not affect islet glucose oxidation at low or high glucose levels. Acarbose also inhibited insulin release induced by the sulfonylurea glibenclamide, whereas insulin secretion stimulated by the cholinergic muscarinic agonist carbachol or the phosphodiesterase inhibitor isobutylmethylxanthine was unaffected by the drug. Moreover, complementary in vivo experiments showed that pretreatment of mice with acarbose to allow for endocytosis of the compound markedly suppressed the insulin secretory response to an intravenous glucose load.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 182. |
- Salehi, S Albert, et al.
(författare)
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Total parenteral nutrition modulates hormone release by stimulating expression and activity of inducible nitric oxide synthase in rat pancreatic islets
- 2001
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Ingår i: Endocrine. - 1355-008X. ; 16:2, s. 97-104
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Tidskriftsartikel (refereegranskat)abstract
- The expression and activities of constitutive nitric oxide synthase (cNOS) and inducible nitric oxide synthase (iNOS) in relation to insulin and glucagon secretory mechanisms were investigated in islets isolated from rats subjected to total parenteral nutrition (TPN) for 10 d. TPN is known to result in significantly increased levels of plasma lipids during the infusion time. In comparison with islets from freely fed control rats, islets taken from TPN rats at d 10 displayed a marked decrease in glucose-stimulated insulin release (4.65 +/- 0.45 ng/[islet x h] vs 10.25 +/- 0.65 for controls) (p < 0.001) accompanied by a strong iNOS activity (18.3 +/- 1.1 pmol of NO/[min x mg of protein]) and a modestly reduced cNOS activity (11.3 +/- 3.2 pmol of NO/[min x mg of protein] vs 17.7 +/- 1.7 for controls) (p < 0.01). Similarly, Western blots showed the expression of iNOS protein as well as a significant reduction in cNOS protein in islets from TPN-treated rats. The enhanced NO production, which is known to inhibit glucose-stimulated insulin release, was manifested as a strong increase in the cyclic guanosine 5'-monophosphate content in the islets of TPN-treated rats (1586 +/- 40 amol/islet vs 695 +/- 64 [p < 0.001] for controls). Moreover, the content of cyclic adenosine monophosphate (cAMP) was greatly increased in the TPN islets (80.4 +/- 2.1 fmol/islet vs 42.6 +/- 2.6 [p < 0.001] for controls). The decrease in glucose-stimulated insulin release was associated with an increase in the activity of the secretory pathway regulated by the cAMP system in the islets of TPN-treated rats, since the release of insulin stimulated by the phosphodiesterase inhibitor isobutylmethylxanthine was greatly increased both in vivo after iv injection and after in vitro incubation of isolated islets. By contrast, the release of glucagon was clearly reduced in islets taken from TPN-treated rats (33.5 +/- 1.5 pg/[islet x h] vs 45.5 +/- 2.2 for controls) (p < 0.01) when islets were incubated at low glucose (1.0 mmol/L). The data show that long-term TPN treatment in rats brings about impairment of glucose-stimulated insulin release, that might be explained by iNOS expression and a marked iNOS-derived NO production in the beta-cells. The release of glucagon, on the other hand, is probably decreased by a direct "nutrient effect" of the enhanced plasma lipids. The results also suggest that the islets of TPN-treated rats have developed compensatory insulin secretory mechanisms by increasing the activity of their beta-cell cAMP system.
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| 183. |
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| 184. |
- Salehi, S Albert, et al.
(författare)
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TPN-evoked dysfunction of islet lysosomal activity mediates impairment of glucose-stimulated insulin release
- 2001
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Ingår i: American Journal of Physiology: Endocrinology and Metabolism. - 1522-1555. ; 281:1, s. 171-179
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Tidskriftsartikel (refereegranskat)abstract
- We examined the relation between nutrient-stimulated insulin secretion and the islet lysosome acid glucan-1,4-alpha-glucosidase system in rats undergoing total parenteral nutrition (TPN). During TPN treatment, serum glucose was normal, but free fatty acids, triglycerides, and cholesterol were elevated. Islets from TPN-infused rats showed increased basal insulin release, a normal insulin response to cholinergic stimulation but a greatly impaired response when stimulated by glucose or alpha-ketoisocaproic acid. This impairment of glucose-stimulated insulin release was only slightly ameliorated by the carnitine palmitoyltransferase 1 inhibitor etomoxir. However, in parallel with the impaired insulin response to glucose, islets from TPN-infused animals displayed reduced activities of islet lysosomal enzymes including the acid glucan-1,4-alpha-glucosidase, a putative key enzyme in nutrient-stimulated insulin release. By comparison, the same lysosomal enzymes were increased in liver tissue. Furthermore, in intact control islets, the pseudotetrasaccharide acarbose, a selective inhibitor of acid alpha-glucosidehydrolases, dose dependently suppressed islet acid glucan-1,4-alpha-glucosidase and acid alpha-glucosidase activities in parallel with an inhibitory action on glucose-stimulated insulin secretion. By contrast, when incubated with intact TPN islets, acarbose had no effect on either enzyme activity or glucose-induced insulin release. Moreover, when acarbose was added directly to TPN islet homogenates, the dose-response effect on the catalytic activity of the acid alpha-glucosidehydrolases was shifted to the right compared with control homogenates. We suggest that a general dysfunction of the islet lysosomal/vacuolar system and reduced catalytic activities of acid glucan-1,4-alpha-glucosidase and acid alpha-glucosidase may be important defects behind the impairment of the transduction mechanisms for nutrient-stimulated insulin release in islets from TPN-infused rats.
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| 185. |
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| 186. |
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| 187. |
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| 188. |
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| 189. |
- Salehi, S, et al.
(författare)
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Lymphedema, serious adverse events, and imaging 1 year after comprehensive staging for endometrial cancer: results from the RASHEC trial
- 2019
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Ingår i: International journal of gynecological cancer : official journal of the International Gynecological Cancer Society. - : BMJ. - 1525-1438 .- 1048-891X. ; 29:1, s. 86-93
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Tidskriftsartikel (refereegranskat)abstract
- In the Robot Assisted Surgery for High Risk Endometrial Cancer (RASHEC) trial, patients with high-risk endometrial cancer were randomly assigned to robot-assisted laparoscopic surgery (RALS) or laparotomy for pelvic and infrarenal para-aortic lymph node dissection. We here report on self-reported lower limb lymphedema (LLL), lymphocyst formation, ascites, and long-term serious adverse events 12 months after surgery.Patients and methodsPatients were enrolled between 2013 and 2016, and 96 patients were included in the per protocol analysis, evenly distributed between RALS and laparotomy. Self-reported LLL was recorded using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire for endometrial cancer—EN24, assessed before and 12 months after surgery. Computed tomography was assessed at baseline, 3, and 12 months. Medical charts were reviewed for serious adverse events and hospital admissions 31 to 365 days after surgery.ResultsAt 12 months after laparotomy and RALS, 61% and 50% patients, respectively, reported LLL (p = 0.31). In univariate analysis, the mean score of LLL at 12 months was significantly higher for laparotomy than for RALS (p < 0.05) and for those without abdominal drainage (p = 0.02), but was not independently associated with LLL in the multivariate analysis. Imaging showed no significant difference in lymphocyst formation or ascites between surgical modalities. No difference was found in serious adverse events and admissions to hospital for any reason. There was no agreement between lymphocyst formation or ascites and self-reported LLL.ConclusionFollow-up 1 year after comprehensive surgical staging for high-risk endometrial cancer showed no differences in self-reported LLL, findings on imaging, or SAE between laparotomy and robot-assisted surgery.
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