Effects of short-term chemical ablation of the GIP receptor on insulin secretion, islet morphology and glucose homeostasis in mice

Glucosedependent insulinotropic polypeptide (GIP) is an incretin hormone secreted by endocrine Kcells in response to nutrient absorption. In this study we have utilized a specific and enzymatically stable GIP receptor antagonist, (Pro(3))GIP, to evaluate the contribution of endogenous GIP to insulin secretion and glucose homeostasis in mice. Daily injection of (Pro(3))GIP (25 nmol/kg body weight) for 11 days had no effect on food intake or body weight. Nonfasting plasma glucose concentrations were significantly raised (p

Communal larval rearing of European lobster (Homarus gammarus): family identification by microsatellite DNA profiling an offspring fitness.

Stock enhancement experiments of European lobster (Homarus gammarus) have been carried out around the Kvitsoy Islands in south-western Norway since 1990. In addition to releases of coded wire tagged lobster juveniles (cultured) and subsequent monitoring of commercial fishery, a lobster hatchery was established in 1997. Several experiments were made on the communal-rearing approach where the performance of mixed larval groups (families) was evaluated under identical conditions. Berried females of wild and cultured origin and their respective fertilised eggs were screened by using microsatellite DNA profiling involving a multiplex set of six lobster specific primers, thereby allowing determination of both parental genotypes. Each female were kept separately during hatching, and the offspring were later mixed and raised in a communal rearing system. The early-larval survival was estimated at stage IV (bottom stage), and the survivors were identified to family and group by microsatellite profiling. Five different communal experiments were conducted, representing offspring from 65 berried females. Of the surviving larvae, 6.3% could not be assigned to family due to degraded DNA and no PCR amplification. Significant differences in early survival between offspring of wild and cultured origin were found in the experiments. No differences between the groups were found in stage IV larval size. Based on the pooled data on survival (as a measure of early larvae fitness) offspring of cultured females displayed a relative fitness of 60% in comparison to offspring from wild females. Large variation in survival was also observed among families within the wild and cultured groups, suggesting a genetic component for these traits and a potential for selective breeding.

Assessment of DNA integrity and morphology of ejaculated sperm from fertile and infertile men before and after cryopreservation

Cryopreservation of human spermatozoa is extensively used in artifical insemination and IVF programmes. Despite various advances in cryopreservation methodology, the recovery rate of functional post thaw spermatozoa remains mediocre, with sperm motility being significantly decreased after freezing. The aim of this study was to investigate the effects of cryopreservation on both DNA integrity and morphology of spermatozoa from fertile and infertile men. Semen samples were obtained from 17 fertile men and 40 infertile men. All samples were prepared by discontinuous Percoll density centrifugation ( 95.0:47.5). Samples were divided into aliquots to allow direct comparison of fresh and frozen spermatozoa from the same ejaculate. Aliquots for cryopreservation were mixed with a commercial cryoprotectant and frozen by static phase vapour cooling before plunging into liquid nitrogen. Thawing was carried out slowly at room temperature. Sperm DNA integrity was determined using a modified alkaline single cell gel electrophoresis ( comet ) assay and sperm morphology analysed using the Tygerberg criteria. DNA of semen and prepared sperm from fertile men was found to be unaffected by cryopreservation. In marked contrast, spermatozoa from infertile men were significantly damaged by freeze- thawing. Cryopreservation had a detrimental effect on morphology of semen and prepared sperm from fertile and infertile men.

Morphology and localization of interstitial cells in the guinea pig bladder: structural relationships with smooth muscle and neurons.

PURPOSE: In the current study we examined the location of interstitial cell of Cajal (ICC)-like cells in the guinea pig bladder wall and studied their structural interactions with nerves and smooth muscle cells. MATERIALS AND METHODS: Whole mount samples and cryosections of bladder tissue were labeled with primary and fluorescent secondary antibodies, and imaged using confocal and multiphoton microscopy. RESULTS: Kit positive ICC-like cells were located below the urothelium, in the lamina propria region and throughout the detrusor. In the suburothelium they had a stellate morphology and appeared to network. They made connections with nerves, as shown by double labeling experiments with anti-kit and anti-protein gene product 9.5. A network of vimentin positive cells was also found, of which many but not all were kit positive. In the detrusor kit positive cells were most often seen at the edge of smooth muscle bundles. They were elongated with lateral branches, running in parallel with the bundles and closely associated with intramural nerves. Another population of kit positive cells was seen in the detrusor between muscle bundles. These cells had a more stellate-like morphology and made connections with each other. Kit positive cells were seen tracking nerve bundles and close to intramural ganglia. Vimentin positive cells were present in the detrusor, of which some were also kit positive. CONCLUSIONS: There are several populations of ICC-like cells throughout the guinea pig bladder wall. They differ in morphology and orientation but all make connections with intramural nerves and in the detrusor they are closely associated with smooth muscle cells.