Search PubMed⌕ Search

Biomedical subjects

R Levy

Publications and source records attributed to R Levy.

At least 667 records · Page 37Linked to original sources

Mental health care in the Lebanon War, 1982.

Lessons in mental health care learned from the October 1973 War were applied in the Lebanon War 1982. A three-echelon system of management was followed according to the practices prevalent in Western armies. The clinical pictures were essentially similar to those observed in other wars. Combat stress reactions (CSR) comprised 15 to 20% of the total casualties during the active phase of the war; the rate of late reactions was 30 to 40% of the total CSR. Treatment on the battlefield was more effective than treatment following airlift to the rear, in returning soldiers to their units. The role of stress in causing CSR, and the importance of leadership and cohesion in its prevention were evident. The important lessons learned from the Lebanon War are discussed and include: 1) the need for a broad definition of CSR; 2) the importance of forward unit intervention; 3) the necessity of mobility and divisibility of mental health treatment units; 4) fighting units should not be dispersed immediately after combat; and 5) the management of stress reactions to be the responsibility not only of the mental health services, but of all sections of the medical corps, both in treatment and prevention.

Combat Disorders↗

Cell-mediated immunity following experimental vaccinations with Candida albicans ribosomes.

The aim of the present study was to ascertain whether cell-mediated immunity (CMI) is induced in animals by vaccination with Candida albicans ribosomes. Delayed type hypersensitivity (DTH) was detected in vivo in ribosome-vaccinated mice and guinea pigs by the footpad swelling and skin tests, respectively. The observed DTH was similar to that induced by live C. albicans organisms. A lymphocyte transformation assay was used for in vitro detection of CMI. The tritiated thymidine incorporation assays revealed that spleen lymphocytes from mice immunized with C. albicans ribosomes were stimulated by the ribosomal antigen. The findings establish that C. albicans ribosomes are able to induce CMI in experimental animals.

Animals↗

Spontaneous release of the Leu-2 (T8) molecule from human T cells.

Sensitive enzyme-linked immunosorbent assays (ELISA) for the detection of human T cell antigens in soluble form have been developed. The assays use mouse monoclonal antibodies and specific anti-Leu sera prepared in rabbits by immunizing with Leu antigens absorbed to monoclonal antibody affinity columns. With these assays, Leu-1, -2, and -3 antigen signals from extracts of as few as 5 X 10(3) cells could be detected. When culture supernatants from various cell lines were tested, Leu-2 antigen, but not Leu-1 or Leu-3, was found to be present. Leu-2 antigen was present only in supernatants from T cell lines that expressed Leu-2 on their cell surface. Leu-2 antigen accumulated progressively in the supernatant of low density culture and its presence did not depend on cell proliferation or on fetal calf serum in the culture medium. The Leu-2 antigen in the supernatant was found to have only one Leu-2a determinant, whereas Leu-2 antigen from cell extracts had at least two determinants. The Leu-2 molecule was effectively purified from supernatant with an anti-Leu-2a affinity column. The purified Leu-2 antigen from supernatant of HPB-ALL cells was a single polypeptide chain of 27,000 mol wt, whereas Leu-2 antigen present on HPB-ALL cell surface was composed of two or more identical polypeptide chains of 33,000 mol wt linked by disulfide bonds. Normal human sera and sera from leukemia patients were also examined for the presence of the Leu-2 antigen. Normal human sera contained low levels of Leu-2 antigen but sera from Leu-2-positive leukemia patients had high levels. These results indicate that Leu-2 antigen is released from human T cells under physiological conditions.

Animals↗

Analysis of the degree of pulmonary thallium washout after exercise in patients with coronary artery disease.

An abnormal increase in pulmonary thallium activity may be visualized on post-stress thallium images in patients with coronary artery disease. Because this increased pulmonary thallium activity usually disappears by the time of redistribution imaging, this study was designed to assess whether measurement of the degree of pulmonary thallium washout between stress and redistribution might improve the detection of increased pulmonary thallium activity in patients with coronary artery disease. Quantitative analysis revealed abnormal (that is, greater than 2 standard deviations of normal values) pulmonary thallium washouts in 59 (64%) of 92 patients with coronary artery disease, but in only 2 (25%) of 8 subjects with angiographically normal arteries (p less than 0.06). By comparison, the visual analysis of pulmonary thallium washout and use of initial pulmonary to myocardial thallium ratio were significantly (p less than 0.05) less sensitive in detecting abnormality in patients with coronary artery disease. Abnormal pulmonary thallium washout was related to both the anatomic extent and functional severity of disease: it occurred with greatest frequency in patients with multivessel disease and in those with exercise-induced left ventricular dysfunction (p less than 0.005). When added to the quantitative analysis of myocardial scintigraphy, the analysis of pulmonary thallium washout increased the detection of coronary artery disease from 84 to 93% (p less than 0.05), but the sample size was too small to assess specificity. Thus, the analysis of pulmonary thallium washout is a useful diagnostic variable because it: 1) provides an objective measurement of abnormal pulmonary thallium activity and is more sensitive than other methods; 2) correlates with both the extent of coronary artery disease and the degree of exercise-induced left ventricular dysfunction, and 3) improves the sensitivity of quantitative myocardial thallium scintigraphy to detect the presence of coronary artery disease.

Aged↗

Biological and clinical implications of lymphocyte hybridomas: tumor therapy with monoclonal antibodies.

Monoclonal antibodies of defined specificity can be produced using hybridoma technology. New attempts are being made to explore the potential of antibody therapy for cancer. Preliminary studies show that problems such as antigenic modulation, circulating free antigen, effector cell shortage, and host anti-mouse immunoglobulin response must be overcome. Uses of monoclonal antibodies in cancer treatment include the administration of unconjugated antibodies or of antibodies coupled to drugs, toxins, or radioisotopes, and the use of monoclonal antibodies in vitro to eradicate residual malignant cells.

Animals↗

Validation of a computerized edge detection algorithm for quantitative two-dimensional echocardiography.

An edge detection algorithm used in conjunction with digitized two-dimensional echocardiograms was applied to validate computerized two-dimensional echocardiographic (2DE) quantitation of cross-sectional areas of canine left ventricular chambers. Images were enhanced by space-time smoothing and dynamic range expansion, after which automatic edge detection was performed by convolving a Laplacian operator with the enhanced image. In an in vitro study of 29 myocardial slabs, computer-derived 2DE measurements of short-axis sections of the left ventricle were compared with manually derived 2DE data and validated against direct measurements of intraluminal areas of myocardial slabs. Correlations of both manually and computer-derived 2D echocardiograms vs direct measurements were equally satisfactory (r = .95 for both). Computer-derived measurements of perimeters tended to underestimate actual perimeters of the endocardial outlines of left ventricular sections. In 13 closed-chest anesthetized dogs, manually and computer-derived left ventricular short-axis areas measured by 2DE techniques showed a good correlation at both end-diastole (r = .91) and end-systole (r = .92). Left ventricular volumes reconstructed from 2DE images were compared with angiographically determined volumes. The computer-enhanced 2DE method correlated against angiography, with r = .93 for end-diastolic and r = .93 for end-systolic volumes. Left ventricular volume correlations between manually and computer-derived 2D echocardiograms were satisfactory, with r = .87 for end-diastole and r = .87 for end systole. We conclude that computerized enhancement and edge detection of 2D echocardiograms obtained in dogs provided accurate analysis of actual left ventricular cross-sectional areas and left ventricular volumes.

Animals↗

The salivary lactoperoxidase system in caries-resistant and -susceptible adults.

In a comparative study of caries-resistant and -susceptible adults, no significant differences were found in the concentrations of lactoperoxidase, thiocyanate, and pre-formed hypothiocyanite in parotid and submandibular saliva, or in hypothiocyanite formed in expectorated saliva over a 60-minute period. The concentrations per se of these components are not critical determinants of caries resistance or susceptibility. Thiocyanate concentration was higher in both unstimulated parotid and submandibular saliva than in the respective stimulated secretions. At comparable flow rates, parotid values were higher than submandibular.

Adult↗

Quantitative computed tomography in elderly depressed patients.

An index of brain tissue density was obtained from the CT scans of 37 elderly depressed patients by measuring Hounsfield Units (HU) in 12 predefined brain areas. Comparisons were made with 23 patients suffering from senile dementia and 36 healthy controls. As a group the depressed patients resembled the dements more than the controls, although analysis of variance indicated differences between all three groups, controls showing the highest HU values and dements the lowest. In the depressed patients ventricular dilatation, which had already been shown to predict increased mortality, was also associated with lower HU levels. The significance of these and other findings is discussed.

Affective Disorders, Psychotic↗

Interface modalities of technical aids used by people with disability.

The objective of this paper was to present some initial thoughts and concepts on the subject of the interface "mechanisms" used between individuals with disability and their technical aids. These interface modalities are considered to be of primary importance in matching adaptive aids to the needs of these individuals. With this in mind, a number of basic premises concerning technical aids, user needs, and user environments are discussed. In addition, an initial framework is presented that describes a series of different levels of interface types. It is hoped that this framework will promote a greater insight into the inherent complexity of interface modalities and thereby stimulate further study.

Persons with Disabilities↗

Cytokeratins of normal epithelia and some neoplasms of the female genital tract.

Cytokeratins are a family of polypeptides of intermediate filaments which in diverse epithelia are expressed in different, yet specific, combinations. We have studied the cytokeratins present in normal epithelia of the female genital tract, in comparison with those present in genital tract carcinomas, by two-dimensional gel electrophoresis of cytoskeletal proteins from microdissected tissues and by immunofluorescence microscopy. Cells of ovarian mesothelium, oviduct, endometrium, and endocervix contain cytokeratin polypeptides nos. 7, 8, 18, and 19. By contrast, tonofilaments of the stratified squamous epithelia of vagina and exocervix contain cytokeratins 4, 5, 6, 13, 14, 15, 16, and 19. Exocervical regions distant from the endo-exocervical junction as well as vagina contain, in addition, the large (Mr 68,000) and basic cytokeratin component no. 1, previously described in epidermis. Endocervical squamous metaplasia at the endo-exocervical border displays a complex cytokeratin pattern, probably due to cell-type heterogeneity. Similar cytokeratin patterns are also observed in genital tract epithelia of the cow and mouse. In human carcinomas of the female genital tract, two main types of cytokeratin patterns can be distinguished. Ovarian carcinomas and endometrial adenocarcinomas express cytokeratins 7, 8, 18, and 19 and, thus, maintain the pattern of the cells of their origin. In endocervical adenocarcinomas the additional presence of component no. 17 has been noted. Nonkeratinizing squamous cell carcinomas of the cervix show a very complex pattern (cytokeratins 5, 6, 7, 8, 13, 14, 15, 17, 18, and 19). Keratinizing squamous cell carcinomas of the cervix display lower complexity and lack cytokeratins 7, 8, and 18. When frozen sections are examined by immunofluorescence microscopy, all epithelia of the genital tract are stained with the monoclonal cytokeratin antibody KG 8.13. Simple epithelia but not the stratified epithelia of vagina and exocervix also react with monoclonal antibodies specific for cytokeratins 8 or 18. The value of cytokeratin polypeptide patterns in distinguishing diverse epithelial cell types of the female genital tract, in elucidating the histogenesis of neoplasms, and in providing a new tool for the differential diagnosis of tumors is discussed.

Adenocarcinoma↗

Biosynthesis, glycosylation, and in vitro translation of the human T cell antigen Leu-4.

Two families of polypeptides were found in immunoprecipitates formed from human T cell lines by using the monoclonal antibody anti-Leu-4. When analyzed by one- and two-dimensional SDS-PAGE, the first family consisted of members with m.w. of 26,000 and isoelectric points that varied from very basic to acidic. The second family consisted of members with m.w. of 22,000 to 23,000 and isolectric points that varied from neutral to very acidic. The biosynthetic processing and intracellular glycosylation of several of these polypeptides were examined. Some, but not all, intracellular forms of the Leu-4 antigen contained N-linked oligosaccharides of the high mannose type. By using messenger RNA from human T cell lines, intracellular forms of Leu-4 were shown to be accurately translated and properly processed by Xenopus oocytes in vitro.

Animals↗

Cutaneous lymphoblastic lymphoma with pre-B markers.

Two children with cutaneous convoluted lymphoblastic lymphoma are reported. Malignant cells from both patients contained cytoplasmic Mu heavy chains characteristic of pre-B-cells and expressed CALLA and la antigens as well. Most cases of convoluted lymphoblastic lymphoma are T-cell-derived neoplasms. The non-T, non-B phenotype found in these two children demonstrates that histology does not necessarily predict immunophenotype. The association of the pre-B phenotype with cutaneous lymphoma has not been previously reported, but may represent a unique clinical-histopathologic-immunologic entity that occurs in young children.

Antibodies, Monoclonal↗

The immunologic and clinicopathologic heterogeneity of cutaneous lymphomas other than mycosis fungoides.

Twenty-one cases of non-Hodgkin's lymphoma with cutaneous involvement, other than mycosis fungoides, were evaluated immunologically, histologically, and clinically. Ten patients presented with skin disease alone, seven with concurrent cutaneous and extracutaneous disease, and four with extracutaneous disease only. Twenty of the 21 cases were nonepidermotropic tumors and were equally likely to express B or T phenotypes. None of the cases expressed a true histiocytic phenotype. Almost all cases expressed la and class 1 HLA determinants. Immunophenotypes were stable regardless of time interval, therapy, or body site sampled in seven of eight patients studied serially. In contrast to mycosis fungoides, the T lymphomas exhibited noncerebriform cytology, tumor la expression, lack of mature helper T-cell phenotype, nonepidermotropic histology, a tendency for marrow involvement, and presented as nodules rather than patches or plaques. Since each T lymphoma expressed an abnormal but uniform T-cell phenotype other than mature cytotoxic/suppressor or helper, the neoplastic population could be distinguished from reactive T cells. Reactive elements averaged one-third of the cellular infiltrates and were mainly T cells and macrophages. Langerhans cells were generally normal in number and distribution. Several histopathologic subtypes were identified with diffuse large cell lymphomas, including immunoblastic lymphomas, comprising 71% of cases (15/21). Prediction of the immunophenotype based on cytologic criteria was correct in 67% of cases (14/21). All errors occurred among the 13 high-grade lymphomas. Survival data were consistent with those of prior studies that have indicated that clinical course is dependent on stage and histologic subtype. Non-Hodgkin's cutaneous lymphomas constitute an immunologically, histologically, and clinically heterogeneous group of neoplasms.

Adolescent↗

A single monoclonal antibody identifies T-cell lineage of childhood lymphoid malignancies.

Immunophenotyping studies with monoclonal antibodies have revealed the heterogeneity of childhood acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL). The lymphoid malignancies of T-cell lineage are particularly heterogeneous and, until now, no single monoclonal antibody has been found to identify all cases of T-ALL and T-NHL. A monoclonal antibody, 4H9, recognizes an antigen of 40,000 molecular weight on normal and malignant T cells. Thirty-six cases of childhood T-ALL and T-NHL were tested, and in all cases, the malignant blast cells were reactive with 4H9, whereas malignant cells from 61 cases of non-T ALL and NHL were not reactive with 4H9. Monoclonal antibody 4H9 is a sensitive and specific reagent for the identification of childhood T-cell ALL and NHL and should be extremely useful in immunophenotyping studies of lymphoid malignancies.

Antibodies, Monoclonal↗