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Biomedical subjects

D Mayer

Publications and source records attributed to D Mayer.

260 records · Page 15Linked to original sources
PubMedDate not supplied

The effect of clotrimazole and triadimefon on 3-hydroxy-3-methyl-glutaryl-CoA-reductase-[EC 1.1.1.34]-activity in Saccharomyces cerevisiae.

Clotrimazole and triadimefon are known as potent inhibitors of ergosterol synthesis in pathogenic yeast and fungi, respectively. As their mode of action generally the inhibition of sterol desmethylation reactions is accepted. We report about a second effect, a "feed-back" inhibition of 3-hydroxy-3-methyl-glutaryl (HMG)-CoA-reductase by accumulation of ergosterol precursors. Addition of lanosterol to intact cells leads to an inhibition of HMG-CoA-reductase as well, but not to fungistatic effects. From the reported data the influences of clotrimazole and triadimefon have to be considered as an inhibition of desmethylation reactions involved in ergosterol synthesis of yeast and fungi with a concomitant decreased production of mevalonate.

Cell Fractionation↗
PubMedDate not supplied

Central venous puncture versus cutdown for permanent pacemaker lead insertion: a modified double introducer technique.

OBJECTIVE: The comparative safety of central venous puncture versus cutdown technique for access to the right heart. EXPERIMENTAL DESIGN: A retrospective review of five hundred and fifty-five single and dual chamber permanent pacemaker implants performed between January of 1987 and December of 1993. SETTING: Review was performed at St. Vincent's Hospital in New York, New York and its teaching affiliate, Huntington Hospital, Huntington, New York. RESULTS: A total of 310 venous punctures were performed. The complication rate was 3.5% overall, with one procedure related death (0.3%) from major venous laceration; a stiff 14 French dilator sheath was employed in this case. There were no comparable complications in the 245 lead placements performed by various cutdown methods. CONCLUSION: Venous cutdown is a safe and effective method for placement of single and dual chamber pacemaker leads. If unsuccessful, the cephalic vein guidewire and double introducer techniques may be employed to rule out placement of dual chamber leads through a hypoplastic cephalic vein, using introducers not larger than 10 French. In properly selected patients, this technique could potentially prevent the complications associated with venous puncture.

Equipment Design↗
PubMedDate not supplied

The unique challenge of small intestinal transplantation.

The past decade has seen major organ transplantation become routine. Although the small intestine can now be successfully transplanted alone or with other organs, the operation presents unique challenges which are reflected in lower survival rates compared with transplantation of other organs. This review presents the development of clinical small intestinal transplantation and its current status.

Adult↗
PubMedDate not supplied

Combined liver-spleen-small intestine grafting in a rat model: role of transplanting additional lymphoid tissue on survival.

The aim of this study was to develop suitable models of combined intestinal grafting to examine the enhancing effect of intestinal grafting with additional lymphoid tissue using 30% of the liver mass and the whole spleen on recipient survival in the absence of immunosuppression. Grafts from DA (RT1a) rats were transplanted orthotopically to PVG (RT1(1)) recipients according to the following design: group 1 (n = 6), en bloc 30% liver/entire SB/spleen; group 2 (n = 7), en bloc 30% liver/SB; group 3 (n = 7), SB/spleen and group 4 (n = 7), SB control for the preceding groups. The orthotopic nature and proximal interposition of the SB graft allowed the assessment of protection afforded by components of the cluster on the SB graft using survival endpoints. Although group 4 hosts survived half as long compared to other groups, statistical significance was reached only in the case of group 1; group 1 MST equalled 15.3 days, significantly higher than group 4 (p = 0.01). Acute rejection was present in every grafted tissue and was equivalent whether liver was included or excluded in the cluster. GVHD was absent postoperatively using clinical or histological criteria; recipient spleens showed hyperplasia, donor spleens depicted lymphocytic depletion on histology. This study determined that statistically proven enhanced survival was obtained only after grafting 30% liver plus spleen with the entire SB. GVHD was rare in the fully allogeneic system despite transplanting a massive load of lymphoid tissue. The surgical models used in this study employing liver in the cluster, address the important question of how best to evaluate the role of heterotopic accessory liver grafting in providing tolerance to co-transplanted small intestine.

Animals↗
PubMedDate not supplied

Comparison of different endocrine stimulation tests in nondiabetic patients with chronic pancreatitis.

BACKGROUND/AIMS: The purpose of this study was to evaluate endocrine functional impairment in nondiabetic patients with chronic pancreatitis and to determine its reliability in the staging of this disease. METHODOLOGY: Eighteen patients with chronic pancreatitis and fasting normoglycemia (fasting blood glucose level < 100 mg/dl) and 10 healthy subjects underwent an oral glucose tolerance test (OGTT), an intravenous glucose test (IGT) and an arginine stimulation test (AST). Blood glucose and serum concentrations of insulin, C-peptide and glucagon were measured before and after stimulation. Exocrine pancreatic function was assessed by the pancreolauryl serum test (PLT), and morphological changes were staged by endoscopic retrograde pancreaticography (ERP), which were rated as I (mild), II (moderate) or III (severe). RESULTS: Glucagon and C-peptide secretions after arginine stimulation were reduced in patients with moderate and severe chronic pancreatitis while no parameter was able to show impaired endocrine function in the early stage (ERP I) of the disease. Serum insulin concentrations proved to be of no use in the diagnosis of pathological B-cell function, since even patients with severe chronic pancreatitis and fasting normoglycemia demonstrated normal insulin secretion. CONCLUSIONS: We conclude that there is a close correlation between morphological changes of the pancreas and functional endocrine reserve capacity, whereas endocrine stimulation tests were not shown to be helpful in the clinical assessment of nondiabetic patients with chronic pancreatitis.

Adolescent↗