Glucose regulates glucokinase activity in cultured islets from rat pancreas

In this study, we have used isolated pancreatic islets cultured for 7 days in 3 or 30 mM glucose to explore whether glucokinase is induced or activated by high glucose concentrations and has related enzyme activity to glucose-stimulated insulin release. Islets cultured in low glucose medium or low glucose medium plus 350 ng/ml insulin did not respond to high glucose stimulation. Islets cultured in medium containing high glucose concentrations showed a high rate of basal insulin secretion when perifused with 5 mM glucose, and the insulin release was greatly augmented in a biphasic secretion profile when the glucose concentration was raised to 16 mM. Islet glucokinase and hexokinase activities were determined by a sensitive and specific fluorometric method. Glucokinase activity was reduced to approximately 50% in islets cultured in low glucose medium with or without insulin present compared to results with fresh islets. However, islets cultured in 30 mM glucose showed that glucokinase activity was elevated to 236% compared to results with fresh islets. It is concluded that (a) glucose is the physiological regulator of glucokinase in the islet of Langerhans and that (b) the activity of glucokinase plays a crucial role in glucose-induced insulin secretion.

[A report of an outbreak of diphtheria in Anshan area]

This paper reports an outbreak of diphtheria and the result of appropriate preventive and therapeutic measures in Anshan area from Dec. 1984 to Dec. 1987. This epidemic of diphtheria occurred mainly in a camp of reform though labour organization and in a spring sanatorium among a population of young adult people with higher level of antibodies. It was proved that the special infection origin was a strain of nontoxic diphtheria bacilli. After a combined management including of injection of a refined diphtheria toxoid and an environment disinfection, the incidence of the disease dropped markedly.

Clinical analysis of four Chinese hemophiliacs with human immunodeficiency virus infection

Human immunodeficiency virus (HIV) is now considered as the causative agent of acquired immunodeficiency syndrome (AIDS). A high risk of AIDS has been reported among patients with hemophilia who received lyophilized commercial factor VIII and IX concentrates of American origin. At a prevalent survey from September to December 1985, HIV antibodies were found in all four patients with hemophilia treated with the batch number W87307, 955 I.U. of American commercial factor VIII concentrate supplied by Armour Pharmaceutical Company, USA. One of the sero-positive patients developed AIDS-related complex (ARC) and died of cerebral hemorrhage. The other three sero-positive patients had abnormalities in cell-mediated immunity. Of them two developed left lumbosacral radiculopathy and hemorrhagic herpes zoster and one remained well so far.

Clinical significance of urine ferritin determination in urologic malignancies

Urine and serum ferritin levels were measured by a double-antibody radio-immunoassay in 96 normal adults and 57 patients with urologic malignancies. In the 96 adults, the urine ferritin levels ranged from 0 to 28 ng/ml. Elevated urine ferritin levels were observed in all 7 patients with renal pelvic carcinoma, 4 of 13 patients with renal carcinoma, 1 of 13 patients with well-differentiated (Grade I) bladder carcinoma, 8 of 19 patients with median-differentiated (Grade II) bladder carcinoma, and all 5 patients with poorly-differentiated (Grades III, IV) bladder carcinoma. These results indicated that urine ferritin assay was helpful in discriminating well-differentiated bladder carcinoma from the poorly-differentiated (P less than 0.01) in addition to differentiating renal pelvic carcinoma from renal carcinoma (P less than 0.05).

The effect of artificial sweetener on insulin secretion. II. Stimulation of insulin release from isolated rat islets by Acesulfame K (in vitro experiments)

The effect of the artificial sweetener Acesulfame K on insulin release in vitro was investigated. Pancreatic islets were obtained from Male Wistar rats. Acesulfame K produced a significant increase in insulin release from incubated islets. This effect was dose- and glucose-dependent. When islets were incubated with different amounts of Acesulfame K (2.5, 7.5 and 15 mM) and 15 mM glucose in the media for one hour, insulin concentrations were 140.2 +/- 21.1, 246.7 +/- 32.4 and 313.9 +/- 37.7 microU/ml, respectively. When 15 mM Acesulfame K was added to a media containing 0, 2.5, 5, 10 and 15 mM glucose, insulin release from incubated islets after 60 min were 25.6 +/- 6.4, 65.4 +/- 12.1, 109.0 +/- 10.0, 229.6 +/- 28.0 and 313.9 +/- 37.7 microU/ml. Incubating islets in the media containing arginine or acetylcholine increased insulin release significantly. However, when Acesulfame K was added to the media containing either arginine or acetylcholine, no further potentiating effect could be detected. The effect of Acesulfame K on insulin secretion was decreased by noradrenaline. However, the addition of naloxone, atropine and propranolol had no significant effect. Somatostatin inhibited insulin release from isolated pancreatic islets, but did not antagonize the action of Acesulfame K. When 2.5 mM Acesulfame K was added to a medium containing somatostatin, the inhibitory effect of somatostatin was totally neutralized. In a perifusion system, Acesulfame K stimulated both phases of insulin secretion. In conclusion, Acesulfame K acts directly on the pancreatic islets and potentiates glucose-induced insulin release.

The effect of artificial sweetener on insulin secretion. 1. The effect of acesulfame K on insulin secretion in the rat (studies in vivo)

Acesulfame K is an artificial sweetener which has been used in the food industry for some years. As yet no metabolic effects have been reported. It was reported that the sweetener can induce a cephalic phase of insulin secretion. To analyse the mechanism of this phenomenon, we studied the effect of Acesulfame K on insulin secretion in vivo. Male Wistar rats, weighing 250-300 g were fasted overnight and anaesthetized with phenobarbital. A silicon catheter was inserted into the right cervical vein for injection of test substances and for obtaining blood samples. In some experiments, another catheter was inserted into the left cervical vein for continuous infusion. Blood samples were drawn at 0, 5, 10, 15, 30 and 60 min after injection, and at -10, 0, 10, 20, 30, 40, 60, 80, 100 and 120 min after the infusion started. Injection of Acesulfame K (150 mg/kg body weight) increased the plasma insulin concentration at 5 min from 27.3 +/- 3.0 microU/ml to 58.6 +/- 4.2 microU/ml without any significant change in the blood glucose. Infusion of Acesulfame K (20 mg/kg body weight/min) for one hour maintained the insulin concentration at a high level (about 85-100 microU/ml) during this period, and at the same time blood glucose was gradually reduced from 103.0 +/- 7.3 to 72.0 +/- 7.2 mg/dl. When using different amounts of Acesulfame K, the insulin secretion was stimulated in a dose-dependent fashion. The effect of Acesulfame K on insulin secretion was similar to that observed by injecting or infusing the same doses of glucose (150 mg/kg) body weight for injection and 20 mg/kg body weight/min for infusion), except that no hyperglycemia was observed with Acesulfame K.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-decay, bremsstrahlen, and the origin of molecular chirality

A brief review is presented of the Vester-Ulbricht beta-decay Bremsstrahlen hypothesis for the origin of optical activity, and of subsequent experiments designed to test it. Certain of our experiments along these lines, begun in 1974 and involving the irradiation of racemic and optically active amino acids in a 61.7 KCi 90Sr-90Y Bremsstrahlen source, have now been completed and are described. After 10.89 years of irradiation with a total Bremsstrahlen dose of 2.5 X 10(9) rads, crystalline DL-leucine, norleucine, and norvaline suffered 47.2, 33.6, and 27.4% radiolysis, respectively, but showed no evidence whatsoever of asymmetric degradation. D- and L-Leucine underwent about 48% radiolysis and showed 2.4-2.9% radioracemization. Other samples in solution were too severely degraded to analyze. Probable intrinsic reasons for the failure of the Vester-Ulbricht mechanism to afford asymmetric radiolysis in the present and related experiments involving beta-decay Bremsstrahlen are enumerated.