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The effects of an electron dense thiol reagent, Hg phenylazo ferritin, on β cell ultrastructure was studied in cell suspensions from mouse pancreatic islets. This type of thiol reagent induced severe damage in the β cells. The ferritin particles were traced with the electron microscope and found to be bound to the plasma membrane as well as to various cytoplasmic structures. The β cell cytotoxic a
Mouse pancreatic islets microdissected free from, or surrounded by, exocrine cells were used to study the effects of secretin and choleeystokinm-pancreozymin on insulin release. Both secretin and cholecystokinin-pancreozymin potentiated glucose-stimulated insulin release regardless of whether exocrine cells were present. The results fail to support the idea that the presence of the exocrine parenc
Pancreatic islets, isolated from the pancreas of obese-hyperglycemic mice, were used to prepare free islet cells in suspension. Batches of 100 islets were disrupted by mechanical shaking for 10 sec in a Ca2+-free HEPES-buffered Krebs-Ring'er medium containing 1 mM EGTA. From 200-500 islets, about 2.2×106 cells could be obtained in suspension, corresponding to a yield of roughly 55% as calculated f
Body acceleration due to heartbeat-induced reaction forces can be measured as mobile phone accelerometer (m-ACC) signals. Our aim was to test the feasibility of using m-ACC to detect changes induced by stress by ultra-short heart rate variability (USV) indices (standard deviation of normal-to-normal interval-SDNN and root mean square of successive differences-RMSSD). Sixteen healthy volunteers wer
Mice, 7-8-mo old, of the C57BL/KsJ-db strain and homozygotic for the mutant gene db, exhibited marked hyperglycemia and moderately elevated serum insulin levels. Light and electron microscopy provided evidence of a slightly decreased proportion of β cells in the pancreatic islets, irregular islet architecture with intraislet ducts, and degenerative as well as hypertrop
d-Glyceraldehyde stimulated the release of insulin from pancreatic islets of Umeå- ob ob-mice whether or not glucose was present in the medium. Like the action of glucose, that of d-glyceraldehyde was biphasic in time, exhibited a sigmoidal dose-response relationship, was potentiated by theophylline, arginine, iodoacetamide, or l-glyceraldehyde, and was inhibited by epinephrine, 2,4-dinitrophenol,
Pancreatic islets rich in β cells and microdissected from noninbred ob/ob mice contained about 15 pmol sialic acid per μg dry weight as determined by a microversion of the Warren thiobarbituric acid method. Removal of half of the sialic acid by treatment with Clostridium perfringens neuraminidase had no effect on the islet content of insulin, moderately inhibited glucose oxidation, and resulted in
Glucose (20 mM) released insulin from pancreatic islets of C57BL 6J- db2J db2J mice, the response being potentiated by 1 mM 3-isobutyl-1-methylxanthine. Islets of C57BL KsJ- db db mice failed to respond to glucose and released only little insulin when challenged with both glucose and methylxanthine. After incubation with 0 or 20 mM glucose alone the islet content of adenosine 3′:5′-cyclic monophos
Chloromercuribenzene-p-sulphonic acid (0.1 mM) or 5,5′-dithiobis-(2-nitrobenzoic acid) (1 mM) alone had no effect on cyclic AMP in microdissected pancreatic islets of non-inbred ob/ob mice. In the presence of 1 mM 3-isobutyl-1-methylxanthine, the mercurial increased and the disulphide decreased the cyclic AMP content. Both sulphydryl reagents stimulated insulin release whether 3-isobutyl-1-methylx
Treatment of pancreatic islets from ob/ob-mice with bacterial neuraminidase (0.8 to 40 mU/ml) resulted in a significant decrease of the sialic acid content and of the secretory response to glucose. The inhibitory effect on the glucose stimulated insulin release was reproduced with different batches of neuraminidase from Clostridium perfringens and Vibrio cholera. Treatment with neuraminidase affec
Microdissected pancreatic islets of ob/ob mice were used to study whether glucose induced insulin release is associated with changes of the apparent extracellular space. Glucose at a concentration of 20 mM had no measurable effect on the islet uptake of sucrose and urea. In the presence of these space markers glucose stimulated insulin release significantly. The results do not invalidate the hypot
At a concentration of 1.0 mM, 6,6' dithiodinicotinic acid and 5,5' dithiobis (2 nitrobenzoic acid) stimulated insulin release from microdissected pancreatic islets of hereditary obese (ob/ob) mice. Microperifusion experiments showed that the secretory responses occurred promptly upon exposure to the sulfhydryl reagents. Perifusion with 6,6' dithiodinicotinic acid induced a sustained enhancement of
4-Acetamido-4′-isothiocyanostilbene-2,2′-disulphonic acid (SITS), an amino-reacting probe of plasma membranes, stimulated the release of insulin from micro-dissected pancreatic islets of ob/ob-mice. This effect of SITS was inhibited by adrenaline or by calcium deficiency. SITS did not inhibit the insulin-releasing action of glucose or leucine but rather potentiated the effect of glucose. In contra
The Swedish Parliament and Government has recently sanctioned a new 6 year undergraduate medical degree leading directly to license, followed by a 12 month introduction to work as a certified doctor. The undergraduate education is internationally harmonized and the 23 learning outcomes address competence needs in future Swedish and international health-care. Particular attention is given to profes
The uptake of chloromercuribenzene-p-sulphonic acid (CMBS) was studied in microdissected pancreatic islets of ob/ob-mice. After rapid initial binding, the uptake increased linearly with time, suggesting that CMBS diffused into the plasma membrane. The binding of CMBS was rapidly reversed on exposure to l-cysteine. Whereas glibenclamide had no effect, glucose and 4-acetamido-4′-isothiocyanostilbene
At a glucose concentration of 3mm or less, iodoacetamide had no effect on the release of insulin from microdissected pancreatic islets of ob/ob-mice. At higher glucose concentrations, iodoacetamide exerted both an initial stimulatory and a subsequent inhibitory action. When islets were perifused with 1mm-iodoacetamide and 17mm-glucose the inhibitory action predominated after about 15min of transie
Sulphur-containing analogues of d-glucose were tested for effects on insulin release, d-glucose transport and d-glucose oxidation in microdissected pancreatic islets of obese-hyperglycemic mice. Substituting sulphur for oxygen in the ring structure of d-glucose (5-thio-d-glucose) resulted in a total loss of insulin-releasing ability. 5-Thio-d-glucose inhibited d-glucose-stimulated insulin release,
