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Biomedical subjects

M Levy

Publications and source records attributed to M Levy.

At least 469 records · Page 26Linked to original sources
PubMed1986

Renal failure in dogs with experimental acute pancreatitis: role of hypovolemia.

The factors causing a decline in renal perfusion were studied in anaesthetized dogs with acute pancreatitis 4 h after the forceful injection of bile into the pancreatic duct. In 11 such dogs, glomerular filtration rate (GFR) decreased by 40.4% from the control state (P less than 0.05), whereas the clearance of para-aminohippurate (CPAH) declined by 50.2%. These changes were associated with a 15.3% decline in cardiac output (P less than 0.05) and a 26.2% fall in plasma volume. Glomerular morphology was entirely normal. When hypovolemia was prevented by infusing homologous plasma over the 4-h period of observation, the normally observed decline in GFR, CPAH, and cardiac output was prevented. The decline in plasma volume, associated with a rising hematocrit and declining plasma protein concentration, and the associated decrement in renal perfusion, could be entirely duplicated by the infusion of trypsin, chymotrypsin, elastase, and phospholipase A2 (but not lipase or amylase) into normal dogs. These perturbations also were prevented by the concurrent infusion of 4% albumin in saline. At 24 h, however, the renal failure became unresponsive to volume replenishment. We conclude that the decline in renal perfusion in dogs at 4 h with acute pancreatitis is entirely due to hypovolemia, induced by the release of specific enzymes from the inflamed gland, which causes the loss of protein-rich plasma from the vascular space.

Acute Disease↗
PubMed1986

Newly modified Evans operation enables immediate mobilization. Reinforcement band stabilizes ankle, no cast is used.

A new technique for reinforcement using a modified Evans procedure, which enables immediate mobilization of the foot and ankle after surgery, has been developed. The reinforcement band is implanted parallel to the tenodesis of the peroneus brevis, about 1 cm proximal to the tendon, from a hole in the base of the fifth metatarsus to a hole in the lateral malleolus. Postoperative immobilization and its possible adverse sequelae are eliminated by this procedure. The surgical technique described in this paper was used to treat 13 patients with chronically unstable ankles. In all cases, excellent surgical results were obtained and leg immobilization was virtually eliminated. Physical therapy was begun in the immediate postoperative period, and the rehabilitation period was significantly reduced.

Adolescent↗
PubMed1986

Pharmacokinetics of metamizol metabolites.

When administered to humans, metamizol rapidly undergoes predominantly nonenzymatic biotransformation, yielding a vast number of active and later inactive metabolites. The biotransformational pathways and the clinical significance of the metabolites are discussed in the light of their individual pharmacokinetics.

Acetylation↗
PubMed1986

Urinary sodium retention in chronic liver disease: a summary.

In animal models of developing portal hypertension, sodium retention occurs for several reasons. Firstly, baroreceptors within the liver signal the renal tubule to retain sodium, irregardless of the extracellular fluid volume status or the status of systemic hemodynamics. Secondly, the requirements of the enlarging portal venous space also stimulate the renal tubule to retain sodium and expand plasma volume. During this period plasma levels of renin and aldosterone probably fall, and the circulation becomes overfilled. Eventually the Starling forces become quite disturbed. At this point, plasma levels of renin, aldosterone, catecholamines and antidiuretic hormone (ADH) begin to rise. Thus, the correct description of the appearance of ascites and the pathophysiology of sodium retention should reflect the biphasic nature of the magnitude of the plasma volume, which goes from a state of overfilling to one of underfilling.

Animals↗
PubMed1986

Pharmacokinetic studies of nifedipine and digoxin co-administration.

We have studied the possible interactions between nifedipine and digoxin in 8 healthy subjects in two ways: A. The effect of digoxin (0.25 mg, tablet q.d. for 8 days) on the pharmacokinetics of nifedipine following single-dose (10 mg capsule) administration. Mean values for peak concentration, area under the serum concentration time curve (AUC), total serum clearance and the half-life of elimination of nifedipine did not differ before and concomitantly with digoxin administration. B. The effect of nifedipine (30 mg t.i.d.p.o. for 6 days) on the pharmacokinetics of digoxin following single dose (0.5 mg i.v.) administration. No significant differences were found between the mean values of the half-life of the alpha and beta phases, the AUC and the apparent volume of distribution of digoxin before and concomitantly with nifedipine administration. However, during the later period, the mean cumulative 96 h urinary excretion of digoxin increased by 18% (p less than 0.05) and the renal clearance of digoxin by 26% (p less than 0.05). No change was found, however, in the total plasma clearance of digoxin.

Adult↗
PubMed1985

[Endobronchial granular myoblastoma: therapeutic stance].

The case of a 34-year-old diabetic patient with an endobronchial granular myoblastoma is presented. This tumor was discovered during an episode of acute pneumonia on the same side as the neoplasm. Endobronchial granular myoblastoma is rare; it is sometimes multiple, with some degree of mucosal infiltration. The treatment (monitoring only, endoscopic or surgical resection) is not clearly defined in the literature: we suggest a therapeutic approach taking into account the characteristic features of the tumor (size, location and number) and of the patient (other diseases, age).

Adult↗
PubMed1985

Amplification and purification of UvrA, UvrB, and UvrC proteins of Escherichia coli.

The UvrA, UvrB, and UvrC proteins of Escherichia coli are subunits of a DNA repair enzyme, ABC exci nuclease. In order to amplify these proteins, we have joined the artificial canonical promoter tac (Amann E., Brosius, J., and Ptashne, M. (1983) Gene (Amst.) 25, 167-178) to the uvr genes to obtain plasmids that express these genes under the control of the lac repressor. When cells carrying the tac-uvr plasmids are induced by the gratuitous lac inducer isopropyl-beta-D-galactoside the Uvr proteins are overproduced reaching a level of 10-20% of total cellular proteins after 6-8 h of induction. We have developed methods to purify all three Uvr proteins, UvrA, UvrB, and UvrC, in milligram quantities and to near homogeneity from these overproducing cells. The purified UvrA protein is an ATPase but UvrB and UvrC proteins are not. However, UvrB protein stimulates the ATPase activity of UvrA protein by a factor of 1.5 in the presence of double-stranded DNA and by a factor of about 2.6 in the presence of UV-irradiated DNA but not in the absence of DNA.

Adenosine Triphosphatases↗
PubMed1985

Respiratory consultations in asthmatic compared with non-asthmatic children in general practice.

In a retrospective study we found that before a diagnosis of asthma had been made children with asthma had consulted their general practitioner more often with respiratory symptoms than children who were non-asthmatic under the age of four. In the second, third, and fourth years the number of consultations differed significantly between the two groups. Asthma should be suspected in any child who presents often with respiratory symptoms. This should lead to earlier diagnosis in most cases.

Asthma↗
PubMed1985

Plasma protein binding of dipyrone metabolites in man.

Four metabolites of dipyrone, 4-methylaminoantipyrine (MAA), 4-aminoantipyrine (AA), 4-formylaminoantipyrine (FAA) and 4-acetylaminoantipyrine (AAA) can be identified in human plasma after its oral administration. The plasma protein binding of the metabolites in samples from 20 healthy volunteers was determined by ultrafiltration. None of the metabolites were found to be extensively bound to plasma proteins. The binding of MAA and AA was relatively higher than of FAA and AAA, as expected from their chemical structure. The mean percentage plasma protein binding was 57.6% for MAA, 47.9 for AA, 17.8 for FAA and 14.2% for AAA. The correlation between the unbound concentration in plasma and the total concentrations of MAA, AA, FAA and AAA was linear. No association was evident between the total protein plasma concentration and the extent of binding. The possible therapeutic implications related to protein binding of several analgesic and non-steroidal anti-inflammatory drugs are discussed.

Acetaminophen↗
PubMed1985

Long-lived lymphocytes include lipopolysaccharide-reactive B cells.

We have used a new protocol of prolonged in vivo hydroxyurea (HU) administration which eliminates all cycling and short-lived cells. This treatment kills 99% of non-B non-T bone marrow cells, and it leaves in spleen and bone marrow "long-lived" B- and T-cell populations which represent 33 and 59%, respectively, of the total numbers of lymphocytes found in untreated controls. The relative proportions of B and T cells in spleen or blood of HU-treated mice were practically unaffected, while an increased blood-to-marrow permeability results in markedly abnormal proportions of B and T lymphocytes in bone marrow. Mitogen reactivities of these long-lived lymphocytes recovered either in spleen or bone marrow of HU-treated animals were studied. The results show that such B cells respond perfectly well to the B-cell mitogen lipopolysaccharide, by proliferation and differentiation into Ig-secreting cells, and that T cells proliferate at nearly control levels in response to concanavalin A. This protocol of long-term HU treatment offers the possibility of studying selected long-lived lymphocyte populations, the clonal repertoires and functional properties of which can now be readily approached.

Animals↗