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Biomedical subjects

D Levy

Publications and source records attributed to D Levy.

At least 415 records · Page 23Linked to original sources
PubMed1980

Bovine leukemia virus-specific antibodies in French cattle. III. Prevalence of the BLV-gp 51 radioimmunoassay for the detection of BLV-infected animals.

The control of the spread of BLV infection among cattle requires very sensitive methods of detection. The BLV-gp51 radioimmunoassay presents great advantages over the other serological methods, including the BLV-p24 radioimmunoassay. This is clear from studies of normal animals from the high-leukemia-incidence region which show that anti-gp51 antibodies reach higher titers than anti-p24 or may even exist alone. Moreover, a sequential survey reveals that the anti-gp antibodies appear earlier. On the other hand, it was not possible to detect a viral antigen expression in the tissues of the infected animals.

Animals↗
PubMed1980

Prognostic significance of age in stage I carcinoma of the cervix.

Controversy exists as to the influence of age on the prognosis of patients with carcinoma of the cervix. We present a series of patients with International Federation of Gynecology and Obstetrics (FIGO) stage I squamous cell carcinoma of the cervix, who were treated at a single institution with uniform radiation technics or radical surgery. A multifactorial analysis showed that age above or below 40 was not of prognostic significance after adjusting for race, substage, and treatment. Equal five-year survival was obtained by either radiation therapy or radical surgery. Complications in patients treated with radiation therapy appeared to be more serious than those in the surgical group. Theoretical reasons are advanced to favor surgical management in younger patients.

Adult↗
PubMed1979

Adenocarcinoma of the vagina in a patient with gonadal dysgenesis.

Adenocarcinoma of the vagina is an uncommon tumor. Many theories have been postulated for its etiology and tissue origin. Its occurrence in young women exposed in utero to diethylstilbestrol has pointed to estrogen influence as a possible etiologic factor. A case of adenocarcinoma of the vagina in a patient with gonadal dysgenesis is presented, and histologic and electron-microscopic observations are discussed. This patient is unique in that development of the vaginal neoplasm occurred in the absence of estrogen influence.

Adenocarcinoma↗
PubMed1979

Blood saving techniques: indications and contraindications.

Pre- and peroperative blood saving can be realised in different ways, without inducing important changes in the biological parameters of the organism. Different replacement solutions are studied in detail. Three principal techniques are as follows: a) The peroperative autotransfusion consists in recovering the blood lost in the operative field during the surgical intervention, filtering it and transfusing it at the end of surgery. b) The peroperative normodilution consists in collecting a certain amount of blood (till up 2 l.) from the patients before operation; it is replaced by plasma expanders and transfused at the end of operation. c) The third technique, called the 'frog leap', consists in collecting blood during the weeks preceding surgery, in various amounts in function of the importance of the estimated blood loss. This blood is stored and transfused during intervention.

Blood Preservation↗
PubMed1978

The interaction of the anionic fluorescence probe, 1-anilinonaphthalene-8-sulfonate, with hepatocytes and hepatoma tissue culture cells.

The fluorescence probe 1-anilinonaphthalene-8-sulfonate (ANS) has been used to characterize the anion transport properties of normal hepatocytes and hepatoma tissue culture cells. Incubation of hepatocytes in the presence of ANS (20 micron) resulted in a 35-fold enhancement of fluorescence and a 50 nm blue shift. The time course of this process is biphasic. A rapid initial fluorescence enhancement suggests ANS binding to the plasma membrane, and a slower component reflects the uptake of ANS into intracellular compartments. Analysis of ANS uptake showed this latter process to be saturable, with a Km of 10 micron, to be temperature dependent and to occur only in viable cells. The above observations suggest a carrier-mediated anion transport mechanism. Incubation of hepatoma tissue culture cells with ANS (20 micron) gave a fluorescence emission spectrum similar to that obtained from purified plasma membranes. The kinetics of this interaction only exhibited a rapid initial binding of ANS. The second slow component was now absent, suggesting that ANS transport by the malignant cell system was greatly reduced. Transport of ANS could, however, be stimulated in the presence of the local anesthetic tetracaine. The observed transport was now saturable, temperature dependent, and as in normal hepatocytes, required viable cells, again indicating a carrier-mediated transport system. These studies suggest a significant alteration in membrane function in hepatoma tissue culture cells resulting in a major defect in anion transport.

Anilino Naphthalenesulfonates↗
PubMed1978

Synthesis and properties of a photoaffinity probe for the glucagon receptor in hepatocyte plasma membranes.

The reaction of glucagon with 4-fluoro-3-nitrophenylazide has been shown to afford the photosensitive derivative, Nepsilon-4-azido-2-nitrophenyl-glucagon. The structure and properties of this derivative were established by amino acid analysis, absorption and fluorescence spectroscopy, deamination, Edman degradation and photolysis. This photoaffinity derivative of glucagon has been used to label specifically glucagon binding sites on hepatocyte plasma membranes.

Amino Acids↗
PubMed1977

Bovine leukemia virus specific antibodies among French cattle. II. Radioimmunoassay with the major structural protein (BLV p24).

A radioimmunoassay (RIA) for the major internal protein of the bovine leukemia virus (BLV p24) was established using anti-BLV p24 natural antibodies and purified 125I-labelled BLV p24. The final precipitation of the immune complexes was realized by a preparation of inactivated Staphylococcus aureau Cowan I. Sera from 363 cows belonging to (1) leukemic herds, (2) non-leukemic but BLV-exposed herds, and (3) apparently unexposed herds were studied comparatively in BLV p24 RIA, complement fixation and immunodiffusion. The BLV p24 RIA appeared much more senstive than the two other methods in the detection of positive sera. With this method 100% of the leukemic animals, excluding those with juvenile lymphosarcoma, presented very high antibody titers (greater than or equal to 10,000). Practically all cows with persistent lymphocytosis were also positive with slightly lower levels of antibodies, confirming the relationship between BLV infection and the persistent lymphycytosis. Moreover, about two-thirds of the hematologically suspect animals and one-third of the normal animals from BLV-exposed herds were found positive, whereas 100% of the sera from unexposed cows remained negative for anti-BLV p24 antibodies.

Animals↗
PubMed1977

The interaction of hepatocyte plasma membranes with an azide derivative of procaine.

A photoreactive derivative of procaine, p-azidobenzoyldiethylaminoethanol hydrochloride, has been synthesized and used as a site-directed probe to label hepatocyte plasma membranes. The procaine derivative was shown to have membrane binding and Ca2+ displacement characteristics quite similar to that of procaine. Photolysis of the derivative in the presence of hepatocyte plasma membranes resulted in the covalent incorporation of the probe into both the protein and lipid fractions. Analysis of the labeled membranes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that one membrane protein was significantly labeled with a molecular weight of 21 400 in addition to membrane lipids. Both binding and labeling could be inhibited in the presence of an excess of procaine. The labeled membrane components may be involved in the binding of Ca2+ to the membrane system.

Animals↗