Dietary effects on (pro)insulin biosynthesis and insulin-degrading activity in islets from sand rats.

Sand rats were fed either a vegetable (vegetable group) or a standard pellet diet. After 14-16 weeks, the normoglycemic subgroup selected (pellet group) from the animals that had been maintained on the standard diet showed a modest increase in body weight. Plasma immunoreactive insulin levels were not significantly increased, but glucose-stimulated insulin release was elevated from islets isolated from sand rats of the pellet group. Insulin biosynthesis was estimated in vitro by measuring [3H]leucine incorporation into (pro)insulin at 1.5 or 15 mmol/l glucose. The rate of (pro)insulin biosynthesis was elevated only at 15 mmol/l glucose in islets from those normoglycemic sand rats fed the pellet diet when compared with islets from the vegetable group. Specific insulin-degrading activity, as determined by measuring degradation of 125I-labeled insulin, was also increased for islets from the pellet group. The metabolic state of these sand rats is thus associated with normoglycemia in vivo, and increased stimulated rates of insulin biosynthesis and degradation in pancreatic islets in vitro.

The major histocompatibility complex and insulin-dependent diabetes in BB rats.

The partially inbred strain of BB-Wistar rats showed a varying incidence of the insulin-dependent diabetes-like syndrome. The serological typing of a large sample of BB rats verified the homozygosity for the RTlu haplotype, whereas its parental non-inbred Wistar stock segregated for RTlu and RTla haplotypes. The histogenetical typing of BB rats by skin grafting showed a significantly prolonged rejection of grafts from RTla donors unusual in other RTlu recipients. The presumption of some recombinational or mutational events in the RTl haplotype of BB rats was not verified by the simple F1 skin grafting test from LEW.1U/RTlu standard/donors to F1/LEW X BB/recipients. Skin grafts survived permanently. When trying to get a clear-cut answer whether the RTlu haplotype is associated with the spontaneous occurrence of diabetes in F2/LEW X BB/ X /LEW X BB/hybrids, only 7.4% of RTlu homozygotes were found among 359 weaned animals. Moreover, the partial strain of BB rats became extinct with the F1 generation mainly due to an infection by the mycoplasma. A new sample of outbred BB rats with a low incidence of spontaneous diabetes was found as homogeneous for the RTlu haplotype, too. Preliminary results of typing these rats for the secondary antibody response to pig insulin indicate the low responsiveness contrary to the results given earlier for the RTlu typing strains as high responders. All these results support the idea that the RTlu haplotype of the BB rats might be a variant carrying some mutational change(s) at the RTl.B region.

Slowly progressive congenital myopathy with cytoplasmic bodies--report of two cases and a review of the literature.

Observations on two patients from unrelated families are reported. Both patients were 32 years old and suffered from a congenital affection of the skeletal muscles. In one (case 2) congenital paresis of the dilator muscle of pupil and cardiomyopathy were also present. In both cases muscle biopsy showed pathologic variations of muscle fiber caliber, and in case 1 atrophic fibers were grouped in some places. Inclusions consisting of dense granular and fine filamentous components were found in skeletal muscle fibers, in about a third of the fibers in case 1 and in about a tenth of the fibers in case 2. The shape and submicroscopic structure of these inclusions were consistent with so-called cytoplasmic bodies. Surrounding or apart from the inclusions, the streaming of Z disks or their disintegration were observed. In addition, pure filamentous bodies occurred in the subsarcolemmic position in both cases. Although cytoplasmic bodies are a nonspecific type of inclusion, they were the outstanding structural anomaly in both cases. A basic defect of myofilament biosynthesis is considered to be the cause of the disorder. It is presumably evoked by a neurogenic factor affecting the trophic influence of the neuron on the muscle cell. The course of the disease may (case 1) but need not (case 2) terminate in severe impairment of skeletal muscle function.

[Studies of necrotizing enteritis of suckling piglets (Clostridium perfringens type C enterotoxemia) in industrialized sow breeding units. 5. Control of the disease]. / Untersuchungen zur nekrotisierenden Enteritis der Saugferkel (Clostridium-perfringens-Typ-C-Enterotoxämie) in industriemässig produzierenden Sauenzuchtanlagen. 5. Mitteilung: Bekämpfung der Krankheit.

Recent methods used and experience obtained in the control of necrotising enteritis are reported in this paper, with reference being made to both the pathogenesis and epizootiology of the disease. Two inoculations of the sows, using "Enterotoxämievakzine Dessau bivalent" five and three weeks before parturition, have worked well for prophylaxis. Oral treatment was applied to nursed piglets, using 40,000 I.U. of "Aviapen" and "V-Tablopen" penicillin per animal and day over periods between two and four days, helped to minimise piglet loss, particularly in the period between a fresh outbreak and full effectiveness of immunoprophylactic action. Such treatment was conducted metaphylactically and therapeutically. The first metaphylactic treatment was given within 24 hours from parturition. Combination of mother animal vaccination with the above therapeutic use of those two penicillin preparations worked extremely well in enzootically contaminated stocks and proved to be the most effective approach, for the time being, to controlling necrotising enteritis of nursed piglets. Yet, all those control measures failed to bring about full stock sanitation on industrialised units. Sow trading was not permitted until at least four weeks had elapsed from full effectiveness of mother animal vaccination, with the view to reducing the proliferation of Clostridium perfringens Type C via sales of breeding animals. All sows were given two "Enterotoxämievakzine Dessau bivalent" vaccinations, prior to sale. The animals were sold only to smaller farms (less than 500 sows for breeding) with concentional keeping patterns which were kept under constant diagnostic supervision. Neomycin, oxytetracycline, chloramphenicol, and other antibiotics against which Clostridium perfringens was resistant or in a position to assume resistance were used on endangered stocks only in conjunction with penicillin or not at all. This programme of control has proved to be efficient through a period of more than three years.