Use of an artificial endocrine pancreas in diabetic pregnancy.

Insulin demand of 12 pregnant diabetics has been investigated with an artificial endocrine pancreas. A rise in insulin requirement during pregnancy which can be attributed to the effort of reaching normoglycemia and to the effect of contrainsular hormones has also been observed by this objective method. Assessment of basal insulin demand during the night might be helpful in optimizing conventional therapy by using long-acting insulins for supplementing basal insulin need. According to our results, pregnancy complicated by diabetes can be foreseen as one of the main applications of a glucose-controlled insulin infusion system.     

Application of an artificial endocrine pancreas in the management of the diabetic surgical patient.

Application of the artificial endocrine pancreas in 12 patients undergoing total duodenopancreatectomy and 3 diabetics in whom different operations were performed proved to be safe for the patients with respect to blood glucose control and prevention of ketosis. In the postoperative period, essentially normal blood glucose values were obtained despite high caloric parenteral nutrition.     

Autometallography allows ultrastructural monitoring of zinc in the endocrine pancreas

Zinc is intimately involved in insulin metabolism, its major known role being the binding of insulin in osmotically stable hexamers in beta-cell granules. To investigate the anatomical distribution of zinc ions necessary for insulin binding we examined the rat pancreas by autometallography (AMG). AMG demonstrates chelatable zinc and is a sensitive marker for zinc in vesicles and also a surrogate marker for recently described zinc pumps regulating intravesicular zinc metabolism. Zinc ions were found in alpha- and beta-cell granules, primarily in the periphery of the granules. Only occasionally was zinc seen in other islet cell types. AMG allows the study of the microscopic and ultrastructural localisation of free zinc ions in the pancreas. The applicability of the method at the ultrastructural level in particular makes AMG a very sensitive tool in future studies on the role of zinc ions in the pancreas.     

Pathology of the endocrine pancreas.

An immunocytochemical analysis of 94 pancreatic endocrine tumors revealed that 73 tumors were multicellular. Significant amounts of somatostatin and human pancreatic polypeptide were found by radioimmunoassay in extracts of 19 and 17 tumors resp., in addition to the hormone causing the clinical syndrome. Numerous tumors contained ductular structures. In the surrounding pancreatic parenchyma a proliferation of small ducts and budding-off from the ductular epithelium of endocrine cells was often observed. These features are hallmarks of nesidioblastosis of the endocrine pancreas which is a hyperplasia. In multiple endocrine neoplasia I hyperplasia of the endocrine pancreas is combined with larger nodules, currently labeled tumors. On the basis of these findings it is conceivable that pancreatic endocrine tumors are not primarily neoplastic and autonomous but that they are rather of hyperplastic origin.     

Incorporation of sulfonylurea into N-isopropylacrylamide as an extracellular matrix for an artificial pancreas.

High-molecular-weight N-isopropylacrylamide copolymers with small amounts of sulfonylurea (SU, typically 2-4 mol% in the feed) were synthesized by free radical polymerization in benzene. SU-incorporated polymer solutions (5, 6, 8, and 10% w/v) in a culture medium (pH 7.4, 0.15 M ionic strength) with islet cells were mixed and poured into Millicells which supported gel formation. In order to increase the gelation temperature, the SU-incorporated copolymer gel, p(NiPAAm-co-SU), was blended with the p(NiPAAm-co-AAc) polymer at a ratio of 4 to 96. Interaction between the islet cells and the synthetic matrix of SU-incorporated copolymer gel resulted in effective cell viability and such cell functions as insulin secretion. To verify the specific interaction between the SU (K+ channel closer)-incorporated copolymer and islet cells, the cells were pretreated with diazoxide, an agonist of the ATP-sensitive K+ channel (K+ channel opener), before interaction between the polymer and islet cells. This treatment suppressed the action of SU on the islet cells. The results from this study provide evidence that the SU-incorporated copolymer stimulated insulin secretion by specific interaction between SU moieties in the polymer and the islet cells.     

Attempted suicide by insulin injection treated with artificial pancreas.

An elderly woman with longstanding insulin dependent diabetes tried to commit suicide by injecting 400 units of insulin subcutaneously (usual total daily dose 56 units). She was admitted to hospital within the hour and treated with the aid of an artificial pancreas. This avoided the usual difficulty of the physician having to cope with rapid and substantial fluctuations in blood glucose concentrations and 67 hours after the overdose insulin was reinstituted. Using an artificial pancreas in insulin overdose is an important advance in management and may avoid the need for surgical intervention such as excising the site of injection.     

The endocrine pancreas of Triturus cristatus: an immunocytochemical study

The endocrine pancreas of Triturus cristatus carnifex was studied with the aid of immunocytochemical methods, showing cells immunoreactive to anti-insulin serum (B cells), a small population of cells immunoreactive to anti-glucagon serum only (A cells), rare cells positive to anti-PP serum only (PP or F cells), and a larger population of cells immunoreactive both to anti-glucagon and to anti-PP sera. B cells lied in the core of the islet, while the A/PP cells were located at the periphery, forming digitations extending into the exocrine parenchyma. D cells were present in small number in the islet while they were more numerous scattered in the exocrine parenchyma. A/PP cells as well as D cells showed one or two long cytoplasmic extensions often in contact with blood vessels.     

Test-tube fertilization inNicotiana tabacum by means of an artificial pollen tube culture

Three techniques of the test-tube fertilization by means of an artificial pollen tube culture are described. The essentials for each individual method are:

1. Transfer of pollen tubes from the sugar solution onto the placentae in the test tube.
2. Placing the placentae with ovules onto pollen tube culture.
3. Precultivation of pollen tubes on small cellophane squares placed on the surface of a semi-liquid medium and transfer of cellophane squares along with the pollen culture to the solid medium, over which finally the placentae with ovules are placed.

By means of all the three techniques viable seeds were obtained in vitro. In an artificial medium pollen tubes are able to maintain their fertilizing ability even after the 24 hours cultivation, i.e. at the time after the formation of the gametes.     

Development of a closed-loop artificial pancreas.

A closed-loop glucose controlled insulin infusion system was developed, consisting of elements for continuous blood glucose analysis, a computer control system, and infusion systems. Improvements include decreased size, cost reduction and better performance. The algorithm used was a piecewise linear representation of the sigmoidal curve commonly employed. The apparatus has been applied to simulation of the healthy beta cell and glucose clamp studies.     

Blood glucose monitoring devices: the need for education,supervision and control.

In this decade liver transplantation has been established as the preferred treatment for children and adults with irreversible end-stage liver disease. Biliary atresia in children and nonalcoholic cirrhosis in adults are the most common indications for the procedure. Transplantation currently plays only a minor role in the treatment of hepatic malignant disease. Blood group compatibility between donor and recipient is preferred, but histocompatibility matching (tissue typing) currently has no significant role in the selection of recipients. Approximately 70% of recipients survive for 1 year, and these patients have an excellent prospect of long-term survival. The emerging evidence indicates that the quality of life and rehabilitation of most liver recipients are good. The current success of liver transplantation can be attributed to critical selection of recipients, modern anesthetic and surgical techniques, improved perioperative care, accurate diagnosis of rejection and superior immunosuppression with cyclosporine.     

The antidiabetic action of somatostatin-28 as assessed by the artificial endocrine pancreas: greater potency than somatostatin-14

In order to investigate the action of somatostatin-28 (SS-28) on the metabolic homeostasis of insulin-dependent diabetics, we compared its effects to those of somatostatin-14 (SS-14) in terms of insulin sparing, changes in dextrose demands, glucose fluctuations and behavior of growth hormone and glucagon secretion. Eight insulin-dependent subjects were connected to Artificial Endocrine Pancreas (Biostator) for 84 hours during which they received intravenous infusions of either SS-14, SS-28 or isotonic saline in a randomized order, after a steady state of metabolism had been achieved. Five of the patients received SS-28 100 micrograms/h and SS-14 250 micrograms/h for 10 hours and three of them SS-28, 50 micrograms/h and SS-14 250 micrograms/h for 12 hours. Identical doses of both peptides were administered as bolus infusions prior to the continuous ones. Under SS-28 100 micrograms/h and SS-14 250 micrograms/h patients required 13.5 +/- 2.3 and 14.5 +/- 1.9 U of insulin respectively vs 40 +/- 5.6 U under isotonic saline infusion (mean +/- SEM, P less than 0.005 and P less than 0.01). At the same period the apparatus delivered 15 times more dextrose under SS-28 and 20 times more under SS-14. The magnitude of glucose fluctuations diminished from 64.6 +/- 2.47 mg% without to 41.4 +/- 2 mg% under SS-14 (P less than 0.01) and 46 +/- 3.8 mg% under SS-28 (P less than 0.02). Similar changes were observed in the remaining three patients who received SS-28 in the dose of 50 micrograms/h.(ABSTRACT TRUNCATED AT 250 WORDS)