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Biomedical subjects

M Weiss

Publications and source records attributed to M Weiss.

At least 883 records · Page 49Linked to original sources
PubMedDate not supplied

Effects of NMDA administration in the substantia nigra pars compacta on the striatal dopamine release before and after repetitive exposures to nitrogen narcosis in rats.

Hyperbaric nitrogen-oxygen exposure developed in rats a decrement of the striatal dopamine release, which was reversed by repetitive exposures. This dopamine decrease could be the result of the antagonistic effect of nitrogen on NMDA receptors. The increment of the dopamine release, following repetitive exposures to nitrogen, could be attributed to a desensitisation of NMDA receptors to the effects of nitrogen. To test these hypotheses, male Sprague-Dawley rats were implanted with electrodes in the striatum to measure dopamine release by voltammetry and cannula in the substantia nigra pars compacta for NMDA injection. Free-moving rats were exposed up to 3MPa of nitrogen-oxygen mixture before and after 5 exposures to 1MPa. At the first exposure to 3MPa, the dopamine level decreased (-15%) but is counteracted by NMDA administration. In contrast, after repetitive exposure, the second exposure to 3MPa, induces a 10% dopamine increase. NMDA administration significantly potentiated this increase. Our results neither support the hypothesis of an antagonist effect of nitrogen on NMDA receptors at the first exposure, nor that of a NMDA receptor desensitization following repetitive exposures to hyperbaric nitrogen.

Animals↗
PubMedDate not supplied

[Assessment of flap vitality by measuring tissue oxygen pressure].

The tissue oxygen pressure measurements carried out in 33 freshly operated flaps with a newly introduced needle probe show a relation between the pO2-values and the prognosis of the flaps. In the assessment of clinically doubtful flap vitality (pale or blueish appearance) this method allows the clinician to discriminate grafts in need of therapeutic intervention (drugs, leeching, surgery) from those that need not to be treated.

Adult↗
PubMedDate not supplied

Improving management skills through staff development.

It is the responsibility of nurse educators to improve the management skills of nurses in their institutions. Professional retention and recruitment are enhanced when staff development programs offer information relevant to function in today's competitive marketplace.

Education, Nursing, Continuing↗
PubMedDate not supplied

Accent on people.

Explore the source record for details and available documents.

Attitude of Health Personnel↗
PubMedDate not supplied

Evaluation of a new preservation solution: Celsior in the isolated rat lung. Paris-Sud University Lung Transplatation Group.

BACKGROUND: We compared Celsior solution, a new and original extracellular preservation solution, with blood-based Wallwork's solution. METHODS: In two groups of isolated rat lungs submitted to 4 hours of cold ischemia, pulmonary arterial and venous resistances, coefficient of filtration, and wet-to-dry lung weight ratio were determined at baseline and after 90 minutes of reperfusion. RESULTS: After ischemia-reperfusion, percentage of increases above the respective baseline coefficient of filtration values were 93% +/- 7% in the Wallwork group and 7% +/- 3% in the Celsior group (p < 0.001 versus Wallwork's solution). CONCLUSIONS: These results show that Celsior consistently prevented the ischemia-reperfusion-induced increase in pulmonary microvascular permeability as compared with Wallwork's solution.

Albumins↗
PubMedDate not supplied

Toxoplasmosis after heart transplantation: diagnosis by endomyocardial biopsy.

Protozoal infections such as toxoplasmosis are known complications in heart transplant recipients. Diagnosis of the disease is often difficult. This article describes the course of a patient who had a febrile illness with leukocytosis and neurologic disorders after heart transplantation; all microbiologic and serologic tests of the peripheral blood and the cerebrospinal fluid failed to identify the responsible pathogen. Infection with Toxoplasma gondii was finally diagnosed by endomyocardial biopsy. We conclude that in heart transplant recipients with infections of unclear origin and neurologic disorders, endomyocardial biopsy may be helpful in the diagnosis, especially in cases of toxoplasmosis.

Biopsy↗
PubMedDate not supplied

Rapid growth of cutaneous neuroendocrine (Merkel cell) carcinoma during treatment of refractory cardiac allograft rejection with OKT3 monoclonal antibody.

OKT3 monoclonal antibody has proved to be a potent immunosuppressive agent in treating refractory heart allograft rejections. Recently, however, an increased incidence of lymphoproliferative disorders after OKT3 therapy has been found. This short report describes the rapid growth of a cutaneous neuroendocrine (Merkel Cell) carcinoma, a rare tumor of the dermis promoted by OKT3 administration. Because OKT3 therapy seems to be associated with an increased incidence of neoplasms, frequent patient follow-up is essential.

Carcinoma, Merkel Cell↗
PubMedDate not supplied

Effects of calcium concentration, lactobionate content, and sodium/ potassium ratio of preservation solutions on resting left ventricular pressure and postreperfusion function of rabbit heterotopic heart transplants.

BACKGROUND: We tested the hypothesis that the University of Wisconsin solution has a ionic composition (i.e., intracellular, calcium-free, lactobionate-enriched) that may be beneficial for cold heart graft preservation independently from any additives. METHODS: St. Thomas' Hospital and University of Wisconsin solutions were compared with the following: (1) C solution, a simplified University of Wisconsin-like solution (i.e., intracellular, calcium-free, lactobionate-enriched); (2) A solution, an St. Thomas' Hospital-like solution (extracellular, calcium [Ca2+] = 1.2 mmol/L) in which chloride was replaced by lactobionate; (3) B solution, an intracellular, lactobionate-enriched, calcium-containing solution ([Ca2+] = 1.2 mmol/L). Rabbit hearts were transplanted heterotopically in the abdomen of recipient animals either immediately or after 6 hours of storage. Hemodynamic parameters were recorded 60 minutes after unclamping. RESULTS: After a 6-hour storage, University of Wisconsin and C solutions provided better preservation than B and St. Thomas' Hospital solutions: diastolic pressures were lower; developed pressure and rate of pressure rise were higher. C solution was superior to University of Wisconsin solution only for rate of pressure rise. A solution was intermediary. A significant alteration of resting pressure and hemodynamic parameters was generally observed during the 6-hour storage. Nonsignificant changes of developed pressure and rate of pressure rise were only observed in C and B solutions: This is explained by systolic alteration after immediate reimplantation for the B group and good preservation for the C group. Resting pressure was unchanged over a 6-hour storage only for the C group, but this measure was not determined for University of Wisconsin. A correlation exists for various left ventricular volumes between resting pressure and postreperfusion hemodynamic data. Replacement of chloride by lactobionate (A versus St. Thomas' Hospital) may have improved resting and diastolic pressures by other mechanisms than limitation of net water gain during storage.

Adenosine↗