196 research outputs found

    Overfeeding, Autonomic Regulation and Metabolic Consequences

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    The autonomic nervous system plays an important role in the regulation of body processes in health and disease. Overfeeding and obesity (a disproportional increase of the fat mass of the body) are often accompanied by alterations in both sympathetic and parasympathetic autonomic functions. The overfeeding-induced changes in autonomic outflow occur with typical symptoms such as adiposity and hyperinsulinemia. There might be a causal relationship between autonomic disturbances and the consequences of overfeeding and obesity. Therefore studies were designed to investigate autonomic functioning in experimentally and genetically hyperphagic rats. Special emphasis was given to the processes that are involved in the regulation of peripheral energy substrate homeostasis. The data revealed that overfeeding is accompanied by increased parasympathetic outflow. Typical indices of vagal activity (such as the cephalic insulin release during food ingestion) were increased in all our rat models for hyperphagia. Overfeeding was also accompanied by increased sympathetic tone, reflected by enhanced baseline plasma norepinephrine (NE) levels in both VMH-lesioned animals and rats rendered obese by hyperalimentation. Plasma levels of NE during exercise were, however, reduced in these two groups of animals. This diminished increase in the exercise-induced NE outflow could be normalized by prior food deprivation. It was concluded from these experiments that overfeeding is associated with increased parasympathetic and sympathetic tone. In models for hyperphagia that display a continuously elevated nutrient intake such as the VMH-lesioned and the overfed rat, this increased sympathetic tone was accompanied by a diminished NE response to exercise. This attenuated outflow of NE was directly related to the size of the fat reserves, indicating that the feedback mechanism from the periphery to the central nervous system is altered in the overfed state.

    Is rejection a diffuse or localized process in small-bowel transplantation?

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    Utilization of endoscopy to both visualize and selectively biopsy an intestinal allograft has become the standard for early recognition and treatment of intestinal allograft rejection. Despite the widespread acceptance of the need for selective mucosal biopsies, it has not been shown that the histological features of intestinal allograft rejection are either localized or occur as part of a more diffuse phenomenon within a tubular allograft. To resolve these issues, 88 ileoscopies were performed in 12 small-bowel allograft recipients and mucosal biopsy samples were obtained at 5, 10, and 15 cm, respectively, from the ileal stoma. Each mucosal biopsy was labeled, processed, and evaluated individually for the presence and severity of any evidence for allograft rejection. The data obtained suggest that intestinal allograft rejection is a diffuse process, and biopsies obtained randomly from an ileal graft are likely to demonstrate evidence of allograft rejection when such is present. © 1994 Springer-Verlag New York Inc

    Association of Spermatogenic Failure with the b2/b3 Partial AZFc Deletion

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    Infertility affects around 1 in 10 men and in most cases the cause is unknown. The Y chromosome plays an important role in spermatogenesis and specific deletions of this chromosome, the AZF deletions, are associated with spermatogenic failure. Recently partial AZF deletions have been described but their association with spermatogenic failure is unclear. Here we screened a total of 339 men with idiopathic spermatogenic failure, and 256 normozoospermic ancestry-matched men for chromosome microdeletions including AZFa, AZFb, AZFc, and the AZFc partial deletions (gr/gr, b1/b3 and b2/b3)
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