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Biomedical subjects

M Weiss

Publications and source records attributed to M Weiss.

At least 379 records · Page 21Linked to original sources
PubMed1994

Experimental evaluation of Celsior, a new heart preservation solution.

An original heart preservation solution (Celsior) has been developed, the formulation of which has been designed to fulfil two major objectives: (1) to combine the general principles of hypothermic organ preservation with those specific for the myocardium, and (2) to offer the possibility of being used not only as a storage medium but also as a perfusion fluid during initial donor heart arrest, poststorage graft reimplantation and early reperfusion. The major principles addressed by the Celsior formulation include (1) prevention of cell swelling (by mannitol and lactobionate), (2) prevention of by the Celsior formulation include (1) prevention of cell swelling (by mannitol and lactobionate), (2) prevention of oxygen-derived free radical injury (by reduced glutathione, histidine and mannitol), and (3) prevention of contracture by enhancement of energy production (glutamate) and limitation of calcium overload (high magnesium content, slight degree of acidosis). Two experimental preparations were used: The isolated isovolumic buffer-perfused rat heart model and the heterotopic rabbit heart transplantation model. In isolated heart experiments, hearts were arrested with and stored in Celsior for 5 h at 4 degrees C and subsequently reperfused for 1 h. A similar protocol was used in the transplantation experiments except that the total ischemic time was approximately 1 1/2 h longer (corresponding to 6 h of storage followed by the 25 additional minutes of cold ischemia required for graft implantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1994

Sequential resection of residual abdominal and thoracic masses after chemotherapy for metastatic non-seminomatous germ cell tumours.

Thirty-eight patients with advanced non-seminomatous germ cell tumours (NSGCTs) underwent multiple surgical interventions (two in 33 patients, three in four patients, four in one patient) after cisplatin-based chemotherapy. All patients had normal serum tumour markers but persistent radiographic masses. The larger mass was routinely resected first. Fifteen patients (39%) had dissimilar histological findings at sequential surgical procedures, 12 of whom demonstrated less favourable pathological features during the first operation and three at the second. Patients who underwent both retroperitoneal lymph node dissection (RPLND) and lung resection showed less favourable histological features in the retroperitoneum in nine cases and in the lung in three cases. Eight of 16 patients (50%) without mature teratoma in their primary tumours showed complete necrosis/fibrosis at all surgical interventions, whereas all patients whose primary tumour was classified as malignant teratoma intermediate demonstrated mature teratoma at least at one anatomical site. As histology of post-chemotherapy residual masses cannot be extrapolated from one anatomical site to another, patients usually are properly managed by excision of all residual masses. In particular, in patients with necrosis/fibrosis at lung resection omission of RPLND is not advised.

Abdominal Neoplasms↗
PubMed1994

[Hepatocellular carcinoma in pregnancy].

Primary hepatocellular carcinoma is a very rare disease, especially in association with a pregnancy. We report on a 22-year-old primigravida, who underwent Caesarean section in the 29th week of pregnancy in conjunction with tumour-reductive surgery for hepatocellular carcinoma. The further course of the disease was characterised by an early recurrence and lung metastases. Under palliative chemotherapy with 5-fluorouracil, the patient has been in a state of stable disease for several months. Typical risk factors for the hepatocellular carcinoma do not exist in the patient. Alternative explanations for the aetiology of the disease are discussed.

Adult↗
PubMed1994

Activation of the Dunaliella acidophila plasma membrane H(+)-ATPase by trypsin cleavage of a fragment that contains a phosphorylation site.

Trypsin treatment of purified H(+)-ATPase from plasma membranes of the extreme acidophilic alga Dunaliella acidophila enhances ATP hydrolysis and H+ pumping activities. The activation is associated with an alkaline pH shift, an increase in Vmax, and a decrease in Km(ATP). The activation is correlated with cleavage of the 100-kD ATPase polypeptide to a fragment of approximately 85 kD and the appearance of three minor hydrophobic fragments of 7 to 8 kD, which remain associated with the major 85-kD polypeptide. The N-terminal sequence of the small fragments has partial homology to residues 713 to 741 of Arabidopsis thaliana plasma membrane H(+)-ATPases. Incubation of cells with 32P-labeled orthophosphate (32Pi) results in incorporation of 32P into the ATPase 100-kD polypeptide. Trypsin treatment of the 32Pi-labeled ATPase leads to complete elimination of label from the approximately 85-kD polypeptide. Cleavage of the phosphorylated enzyme with endoproteinase Glu-C (V-8) yields a phosphorylated 12-kD fragment. Peptide mapping comparison between the 100-kD and the trypsinized 85-kD polypeptides shows that the 12-kD fragment is derived from the trypsin-cleaved part of the enzyme. The N-terminal sequence of the 12-kD fragment closely resembles a C-terminal stretch of an ATPase from another Dunaliella species. It is suggested that trypsin activation of the D. acidophila plasma membrane H(+)-ATPase results from elimination of an autoinhibitory domain at the C-terminal end of the enzyme that carries a vicinal phosphorylation site.

Amino Acid Sequence↗
PubMed1994

Modulation of the IL-2 production defect in vitro in Graves' disease.

IL-2 production by mitogen-induced peripheral blood mononuclear cells was reported to be reduced in several autoimmune diseases, including Graves' disease (GD). This production defect in hyperthyroid GD was restored to normal by antithyroid drug therapy or during remission. However, its underlying mechanism and role in the autoimmune process are still uncertain. The present study was undertaken in order to screen the in vitro IL-2 generating system for putative factors responsible for its failure, and to see to what extent this was reversible. Thyroid hormone or antithyroid drugs had no effect on IL-2 production in vitro. Cultures were found to be free of soluble inhibitors of IL-2 production or action. IL-1 deficiency as a cause of the IL-2 defect was ruled out; rather, Graves' adherent cells were found to be activated in being capable of secreting large amounts of IL-1 and prostaglandin E2 (PGE2). The latter was not found to be responsible for the decreased IL-2 production. IL-2 production by Graves' mononuclears was completely restored to normal by: (i) adherent cell depletion, irradiation or substitution with normal adherent cells; (ii) preincubation of mononuclears for 24-72 h before mitogen stimulation; (iii) the synergistic action of a phorbol ester and a calcium ionophore. These data indicate that inhibition by activated adherent cells accounts for the in vitro IL-2 production defect in GD. This inhibition is not mediated by soluble factors, but probably through direct interaction with the producing cells, and is reversible in rested cultures or through a bypassed signal transduction.

Cell Adhesion↗
PubMed1994

How to make research happen: working with staff.

Implementing a research project in a clinical nursing unit requires the researcher to gain cooperation and support from administration, physicians, and the nursing staff. In this article the site coordinators from the Transition of the Preterm Infant to an Open Crib research-utilization project share their strategies for generating support, energizing the staff nurses, assuring compliance with the study, resolving problems, and bringing the project to closure. Many of the strategies used can be applied to other research projects by nurse researchers interested in using clinical nursing units as research sites.

Clinical Nursing Research↗
PubMed1994

PMN cell counts and phagocytic activity of highly trained athletes depend on training period.

We tested the hypothesis that polymorphonuclear leukocyte (PMN) cell counts and phagocytic activity determined by latex ingestion and superoxide anion production are influenced by different training periods. We investigated long-distance runners before and up to 24 h after a graded exercise test to exhaustion during moderate training (MT) and intense training (IT) and compared them with untrained (control) subjects. Cell counts and phagocytic activity at rest and after exercise did not differ significantly between MT and control. On the contrary, IT showed a significant (P < or = 0.05) decrease in PMN cell count at rest (2.55 +/- 0.3 cells/nl) compared with MT (3.63 +/- 0.2 cells/nl) and control (3.41 +/- 0.8 cells/nl). Furthermore, phagocytic activity was significantly reduced (P < or = 0.05) in IT at rest and after exercise compared with MT and control. A strong inverse correlation (r = -0.75; P < or = 0.01) between epinephrine and superoxide anion production was found. These results provide evidence that the phagocytic activity depends on the training period and indicate impaired PMN functions during IT, which might lead to increased susceptibility to infection.

Adult↗
PubMed1994

Mononuclear cell magnesium content remains unchanged in various hypertensive disorders of pregnancy.

Serum magnesium levels, as well as magnesium content of red blood cells and peripheral mononuclear cells, were examined in 31 pregnant women in their third trimester. Ten were preeclamptic; chronic hypertension was found in 10, and 11 were normotensive. Magnesium serum levels were 1.2 +/- 0.1, 1.2 +/- 0.1 and 1.3 +/- 0.1 mEq/l in the normotensives, chronic hypertensives and preeclamptics, respectively. Red blood cell magnesium concentration was 3.4 +/- 0.4, 3.7 +/- 0.7 and 3.5 +/- 0.5 mEq/l, and mononuclear magnesium content was 37.9 +/- 30.6, 27.6 +/- 15.9 and 30.2 +/- 25.7 fg/cell in the same groups, respectively. These changes were not statistically significant. The results do not support the hypothesis that magnesium deficiency is involved in the pathophysiology of preeclampsia.

Adult↗
PubMed1994

Reduction of ischemia-reperfusion injury by pentoxifylline in the isolated rat lung. Paris-Sud University Lung Transplantation Group.

Inhibition of pulmonary neutrophil sequestration attenuates ischemia-reperfusion (IR) lung injury. Pentoxifylline (PTX) reduced pulmonary sequestration of neutrophils and neutrophil-dependent lung injury in several experimental settings but has never been tested in IR models. We hypothesized that PTX may have a beneficial effect on IR lung injury as measured by the coefficient of filtration (Kfc) and may reduce IR-associated sequestration of neutrophils as assessed by lung myeloperoxidase (MPO) activity and by blood neutrophil count decrease during reperfusion. Three groups of isolated blood perfused rat lungs were studied: a time control group (n = 6) was perfused for 3 h, and two groups (n = 10) subjected to 1 h ischemia were treated with PTX or saline before a 2 h reperfusion. The increase in Kfc induced by IR was reduced fivefold by PTX compared with saline (+27 +/- 8% versus +112 +/- 12%, respectively; p < 0.001), and was similar to time controls (+9 +/- 9%). After IR, MPO and blood neutrophil count decrease were lower with PTX than with saline. Changes in Kfc were correlated to the percentage decrease in blood neutrophils during reperfusion. We conclude that PTX reduced rat lung IR microvascular injury. This effect may be mainly caused by decrease in lung sequestration of neutrophils during reperfusion.

Animals↗
PubMed1994

Radical external beam radiotherapy of urinary bladder carcinoma. An analysis of results in 500 patients.

Between 1970 and 1985, 500 patients with urinary bladder carcinoma received external beam radiotherapy with curative intent at the Centre of Oncology in Kraków. The 5-year survival without evidence of cancer for T1 patients was 100% (5/5), for T2 48.7% (19/39), for T3 32% (128/400), and for T4 7.1% (4/56). In our patients the clinical T category was the only pretherapeutic prognostic parameter of statistical significance confirmed in uni- and multivariate analysis. The tolerance of therapy was poorer in patients who had partial transurethral resection of the bladder tumour performed prior to radiation therapy, and in those whose bladder volume was less than 200 ml. The additional irradiation of regional (pelvic) lymph nodes seemed to improve survival of patients with T3 bladder carcinoma.

Aged↗
PubMed1994

Effects of sedatives and their solvents on the neutrophil granulocyte function.

We have examined the effects of commercially available preparations and drug-free solvents of Midazolam (Dormicum) and Propofol (Disoprivan) by N-formyl-methionyl-leucyl-phenylalanine (FMLP) -induced polymorphonuclear cell (PMN) chemiluminescence system. In the case of propofol and drug-free solvent, PMN chemiluminescence was suppressed. With Midazolam, only the active drug depressed PMN chemiluminescence.

Humans↗
PubMed1994

[Clinical and radiological results with the spherical Mecring as acetabulum prosthesis in hip joint diseases].

The recent experiences which the university hospital in Heidelberg has made with the spherical Mecring must be valued positively. Clinical, radiological and subjective dates from 147 patients were worked up retrospectively. Indeed, the positive results must be considered as relative because of the short respectively medium-term period of control. Nevertheless, the repeated improvement in the second group after a period of postexamination on a average of 3.05 years lets hope for positive long-term results. In the period between 1985 and 1990 three sockets had to be changed. The reasons that the sockets loosened were not specific for the screwing but depending on the individual patients or on the implantations and technical circumstances. The negative results achieved by Engh et al. 1990 could not be recognized (8). He measured a radiological instability of 18% and a technical instability of 28%. What Engh did was measuring simple review photographs and extracting valuable material from them while using geometrical methods. This method shows various measuring mistakes. Therefore Engh's conclusion that the screwing should not be used for implantation because of its displacement in the bones is doubtful. The doubts seem to be supported by the results of our comparison of two series of X-ray photographs with defined different pelvis positions of the same patient. The screwing seemed to be significantly displaced in cranio-medial direction. This was proved by experimental photographs with a pelvis raised to 6 cm in contralateral direction. But the results were a matter of radiological illusion. Radiological migration of the screwing is only provable by complicated X-ray analyses steered with the computer. These big X-ray series are not accessible at the time.

Acetabulum↗
PubMed1994

Do barbiturates and their solutions suppress FMLP-induced neutrophil chemiluminescence?

The dose-response relationship of four commercially available barbiturates (methohexitone, pentobarbitone, phenobarbitone and thiopentone) and of their drug-free solutions on the production of oxygen radicals by neutrophils were tested by N-formylmethionyl-leucyl-phenylalanine (FMLP)-induced granulocyte chemiluminescence and in a cell-free chemiluminescence system. Methohexitone had no effect on neutrophil chemiluminescence. Pentobarbitone, phenobarbitone and thiopentone dose-dependently decreased FMLP-induced chemiluminescence and cell-free chemiluminescence. Suppression of neutrophil chemiluminescence by pentobarbitone and phenobarbitone was due to effects of the drug-free solutions and an osmolality greater than 360 mosmol kg-1. Only thiopentone suppressed granulocyte chemiluminescence drug-specifically. The physicochemical properties of commercially available barbiturate preparations and their solutions, as well as free radical scavenging capacity, have to be considered if these preparations are used to evaluate drug-specific effects on the production of oxygen radicals by neutrophils.

Barbiturates↗
PubMed1994

Should magnesium therapy be considered for the treatment of coronary heart disease? I. A critical appraisal of current facts and hypotheses.

When given at physiological doses, therapy with magnesium corrects the alterations in cellular function resulting from magnesium deficiency, whereas at higher dosages, which induce hypermagnesaemic levels, magnesium possesses pharmacological effects, such as the inhibition of the calcium influx: this may alter the electrophysiological properties of heart cells, decrease catecholamine secretion, influence the synthesis of prostacyclin and/or alter platelet function. The evidence that magnesium deficiency has untoward effects in patients with ischaemic heart disease is only circumstantial and direct proof that magnesium deficiency causes cardiac disorders is at present lacking. A ubiquitous calcium-channel blockade mechanism is the main and well-established way of action whereby magnesium acts at pharmacological levels; other mechanisms may be involved as well but at present remain questionable or unsettled. On the basis of the present knowledge, beneficial effects may thus be expected from high dose intravenous magnesium therapy in the setting of acute myocardial infarction with respect to mortality rates, even when there is concurrent thrombolytic therapy, as recently demonstrated by the large LIMIT-2 study, although this could not be confirmed from the ISIS-4 trial. High dose intravenous magnesium is also a first choice therapy for terminating torsade de pointes ventricular tachycardia but cannot be considered an established therapy for other cardiac rhythm disturbances nor for settings other than acute myocardial infarction in the case of ischaemic heart disease. The preliminary evidence that magnesium deficiency has a high prevalence in patients with ischaemic heart disease and that it may have a detrimental influence on the course of ischaemic heart disease needs to be validated by larger prospective and controlled clinical studies. Magnesium therapy in ischaemic heart disease thus proves a promising approach which, however, requires that the respective pharmacological and physiological effects be distinguished and further delineated and that the type and stage of ischaemic heart disease be characterized.

Animals↗
PubMed1994

Lyme disease: an infectious and postinfectious syndrome.

OBJECTIVE: To determine chronic morbidity and the variables that influence recovery in patients who had been treated for Lyme disease. METHODS: Retrospective evaluation of 215 patients from Westchester County, NY, who fulfilled Centers for Disease Control case definition for Lyme disease, were anti-Borrelia antibody positive and were diagnosed and treated at least one year before our examination. RESULTS: Erythema migrans had occurred in 70% of patients, neurological involvement in 29%, objective cardiac problems in 6%, arthralgia in 78% and arthritis in 41%. Patients were seen at a mean of 3.2 years after initial treatment. A history of relapse with major organ involvement had occurred in 28% and a history of reinfection in 18%. Anti-Borrelia antibodies, initially present in all patients, were still positive in 32%. At followup, 82 (38%) patients were asymptomatic and clinically active Lyme disease was found in 19 (9%). Persistent symptoms of arthralgia, arthritis, cardiac or neurologic involvement with or without fatigue were present in 114 (53%) patients. Persistent symptoms correlated with a history of major organ involvement or relapse but not the continued presence of anti-Borrelial antibodies. Thirty-five of the 114 (31%) patients with persistent symptoms had predominantly arthralgia and fatigue. Antibiotic treatment within 4 weeks of disease onset was more likely to result in complete recovery. Children did not significantly differ from adults in disease manifestations or in the frequency of relapse, reinfection or complete recovery. CONCLUSION: Despite recognition and treatment, Lyme disease is associated with significant infectious and postinfectious sequelae.

Acute Disease↗
PubMed1994

[Bovine virus diarrhea/mucosal disease: a review].

Infections with the Bovine Viral Diarrhea/Mucosal Disease Virus (BVDV) are widespread and cause a variety of diseases including reproductive disorders, abortion and malformation, pneumoenteritis, thrombocytopenia and mucosal disease. Together with the closely related border disease virus of sheep (BDV) and European Swine fever virus (CSFV), also referred to as Hog Cholera virus, BVDV is now classified in the genus pestivirus of the Flaviviridae family. The BVDV exists in two biotypes, noncytopathic and cytopathic, the latter differing in structural proteins from the noncytopathic biotypes. In virus-free animals infection is transient and mostly subclinical or mild but may also lead to an array of diverse symptoms such as pneumoenteritis (often in combination with other microorganisms). Infection of the developing fetus early in gestation with a noncytopathic biotype of BVDV may result in persistent infection and birth of apparently healthy calves. Such calves may later in their lives develop Mucosal Disease, a lethal course of infection associated with a mutation to the cytopathic biotype or superinfection with a cytopathic BVDV antigenically similar to the non-cytopathic virus already present in these animals. Diagnosis of infections with BVDV is based on the clinical symptoms and demonstration of virus. Paired serum samples allow the detection of seroconversion in acute infections while persistently infected animals are immunotolerant and generally lack antiviral antibody. Although generally found in their respective host species, pestiviruses of cattle, sheep and pigs are capable of crossing the species barrier into the other species. The existence of pestiviruses in wild ruminants and boars may complicate control strategies that are aimed at removing virus carriers and the control of animal movements.

Animals↗