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Biomedical subjects

E F Pfeiffer

Publications and source records attributed to E F Pfeiffer.

464 records · Page 26Linked to original sources

Effect of naloxone on pancreatic and gastric endocrine function in response to carbohydrate and fat-rich test meals.

The present study was designed to determine the effect of naloxone, a specific opiate receptor antagonist, on postprandial levels of insulin, glucagon, pancreatic polypeptide (PP), somatostatin-like immunoreactivity (SLI) and gastrin in response to carbohydrate and fat-rich test meals in a group of 6 healthy volunteers. The addition of naloxone to a meal consisting of 50 g sucrose dissolved in 200 ml water augmented the rise of plasma insulin levels significantly during the first 30 min after its ingestion and reduced the rise in plasma insulin and pancreatic polypeptide and elevated glucagon levels during the last 30 min of the experimental period. When sucrose was dissolved in 200 ml cream the addition of naloxone augmented the postprandial rise of insulin levels between 15 and 60 min after ingestion of the meal and elicited an increase of plasma SLI and PP levels throughout the entire experimental period which indicates that post-prandial levels of insulin, glucagon, PP and SLI are modulated via endogenous opiate receptors during the ingestion of carbohydrate and fat test meals and that this effect depends on the composition of the ingested nutrients. These data raise the possibility that endogenous opiates participate in the regulation of postprandial insulin, glucagon, somatostatin and pancreatic polypeptide release not only in certain disease states as demonstrated recently for insulin secretion in type II diabetes mellitus but endogenous opiates may also be of importance under physiological conditions.

Adult↗

["Glucosensor Unitec Ulm". A portable, continuously measuring glucose sensor and monitor].

The "Glucosensor Unitec Ulm" is the first commercially available, portable glucose monitor that permits continuous measurement in venous blood under ambulatory conditions for up to 256 hours. The device weights 850 g, and measures 15 x 19 x 7 cm. Depending on the flow rate of the pump, the blood requirement is 15-25 ml/24 h. The size of the built-in-memory is 32 kByte, enough to store 3180-15,900 glucose values. The "24 hour glucogram" obtained under day to day living conditions permits the detection of disturbances of carbohydrate metabolism. Thus, early abnormalities of type II diabetes can be detected as well the degree of blood glucose normalization in patients suffering from severe insulin-dependent diabetes. Moreover, the effects of glucose-lowering drugs can be analyzed objectively. Finally, this portable glucose monitor permits the recognition of hypoglycemia induced by insulin administration or endogenous insulin overproduction due to tumors.

Blood Glucose↗

Comparison of the biologic activity of biosynthetic human insulin and natural pork insulin in juvenile-onset diabetic subjects assessed by the glucose controlled insulin infusion system.

To assess the biologic activity of biosynthetic human insulin (BHI) synthesized by Escherichia coli, six insulin-dependent juvenile-onset diabetic subjects were studied with BHI and natural pork insulin, by means of the glucose controlled insulin infusion system (GCIIS). First, after an overnight normalization of blood glucose levels, the 24-h insulin requirement was determined while the patients were consuming a diet of 30 kcal/kg. Then, the amount of glucose necessary to maintain normal blood glucose levels during a 5-h intravenous infusion of BHI and pork insulin, respectively, was assessed. Both studies demonstrate that in the insulin-dependent diabetic subject, BHI is at least as effective as natural pork insulin and may, therefore, be useful for the treatment of insulin-dependent diabetes mellitus.

Adolescent↗

Potency of biosynthetic human insulin determined in vitro.

Biosynthetic human insulin (BHI) obtained from separately synthesized A- and B-chains by recombinant DNA technology with Escherichia coli fermentation was compared with human and pork insulin of high purity in vitro. Applying four biologic tests (glucose oxidation and glucose incorporation into the lipids by rat epididymal fat pads, inhibition of lipolysis, and ATP depletion of isolated fat cells) and three receptor assays (binding competition with human fat cells, IM-9 lymphocytes, and rat liver cell plasma membranes), we could not discern significant differences of the half-maximum response by these seven methods. The only variance occurred with the ATP-depletion assay. This method disclosed 10% greater maximum reversion of isoproterenol-induced ATP depletion by BHI when compared with pork insulin.

Adenosine Triphosphate↗

Incidence of hypoglycemic episodes in diabetic patients under continuous subcutaneous insulin infusion and intensified conventional insulin treatment: assessment by means of semiambulatory 24-hour continuous blood glucose monitoring.

The incidence and magnitude of hypoglycemia (i.e., blood glucose values less than 50 mg/dl) were assessed by continuous blood glucose monitoring over 24 h in 10 insulin-dependent diabetic (IDD) patients treated with continuous subcutaneous insulin infusion (CSII) and 9 IDD patients under intensified conventional treatment (ICT). A newly developed, battery-powered blood glucose monitor was employed. Patients were thus enabled to move freely in the hospital premises. Despite similar quality of previous blood glucose control (HbA1: 8.0 +/- 0.05% CSII versus 8.0 +/- 0.3% ICT, mean +/- SEM), the obtained profiles showed better regulation under CSII treatment (mean blood glucose [MBG], 99.6 +/- 10.0 versus 133.1 +/- 7.4 mg/dl; M-value, 12.3 +/- 3.5 versus 26.2 +/- 4.1; mean amplitude of glycemic excursion [MAGE], 71.9 +/- 8.7 versus 132.9 +/- 14.2 mg/dl; CSII versus ICT, mean +/- SEM). The incidence of blood glucose values less than 50 mg/dl was 9/10 patients (CSII) and 5/9 patients (ICT). In both groups, hypoglycemia was most frequent at noon and was related to elevated pre- and postprandial free insulin levels. Patients became aware of hypoglycemia only in 6/23 episodes (CSII) and 6/8 episodes (ICT). Our data indicate that CSII as well as ICT may result in postprandial hyperinsulinemia leading to frequent hypoglycemic episodes of variable length, reassessing the traditional experience of close correlation between aggressive insulin therapy and enhanced hypoglycemic risk.

Adolescent↗

Glucagon as a non species-specific regulator of the glycaemia in honeybee (Apis mellifica).

It is known that hormones which exist in vertebrates are very old in respect to evolution. The presence of insulin and glucagon in insects had already been suggested in the early sixties. In this study honeybees are living in an "artificial hive" in the German laboratory under exactly standardized conditions. In the French laboratory standardized conditions yielded because only emerging worker bees were used i.e. those which were just slipping from the honeycomb alveoli. It seemed of interest to introduce an in vivo model in which one animal is punctured at tergum III in order to gain 1 microliter hemolymph using a glass capillary tube . *For the first time it is possible to puncture one animal three times. The main sugars in the hemolymph were silylated* and determined by gas chromatography in the German resp. by nano thin layer chromatography in the French laboratory. 0-500 ng porcine glucagon resp. the same amount of purified bee glucagon were injected to the animals and the action on carbohydrates observed during 2 hours. Similar to the action of glucagon in vertebrates, carbohydrate metabolism although completely different, appears to be regulated in part in this invertebrate stem. It is concluded that glucagon may represent a key hormone for degradation of the glycogen stores.

Acclimatization↗

A comparison of premeal subcutaneous insulin infusion and injection in type I diabetic patients under continuous basal subcutaneous insulin delivery.

Blood glucose control under continuous subcutaneous insulin infusion (CSII) was assessed in five type I diabetic patients by measurement of mean blood glucose and M-values. These results were compared with the data obtained from treatment with constant basal subcutaneous insulin delivery supplemented by injection of regular insulin before meals into changing sites of the anterior abdominal wall. CSII treatment gave significantly (P less than 0.05) better results. It might be assumed that this is due to the more reliable insulin absorption from an unchanged site.

Adolescent↗