M C Simon — Page 5 | PubMed Health

PubMedDate not supplied

Islet transplantation in diabetic rats. Long-term follow-up of glucose tolerance.

Inbred Lewis rats made diabetic by streptozotocin were transplanted with 430-870 islets from syngenic donors via the portal vein. Though fasting plasma glucose was normal, the tolerance to glucose given intraperitoneally (IPGTT) or orally (OGTT) remained impaired one month after transplantation. The higher the number of islets, however, the better the glucose tolerance. The results of IPGTT and OGTT in each animal correlated. Fasting plasma insulin levels were within the normal range suggesting that the action of insulin on the liver and its degradation by the liver is impaired due to the limited number of hepatocytes subjected to high insulin concentrations. Eight months after transplantation, the plasma insulin and glucose responses to OGTT were still unchanged while those of the less physiological IPGTT were worse. Thus, the functional capacity of the transplanted endocrine tissue does not appear to change with time.

Animals↗

PubMedDate not supplied

Preparation of a detailed restriction map of the avian leukosis virus MAV-2(O).

Unintegrated MAV-2(O) DNA was isolated from infected chicken embryo fibroblasts and inserted into the lambda bacteriophage vector lambda gtWES lambda B. Three x 10(6) bacteriophage plaques were screened, yielding a total of seven clones, six of which contained DNA representing the complete MAV-2(O) genome. Viral DNA was isolated from four of the clones and was used to transfect chicken embryo fibroblasts. All four clones produced virus as monitored by reverse transcriptase assay. When the four cloned viruses were inoculated into 10-day-old embryos, all hatched chickens developed osteopetrosis. One clone, lambda 9, induced osteopetrosis at a rate of onset and severity identical to that induced by the MAV-2(O) parental stock. This clone was selected for further study. To facilitate restriction mapping, the viral DNA from lambda 9 was subcloned into plasmid vector pUC 12 to construct a plasmid called p9. Cleavage of p9 DNA with single and multiple restriction endonucleases and hybridization with gene-specific probes identified the restriction fragments obtained. A comprehensive restriction map of cloned MAV-2(O) was generated and is compared with published maps and sequences of other avian retroviruses.

Animals↗