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Biomedical subjects

A Levin

Publications and source records attributed to A Levin.

At least 19 recordsLinked to original sources
PubMed1992

Crossreacting human lymphoma idiotypes.

We have examined an unselected series of 72 lymphomas of diverse histologies with a panel of mouse monoclonal antibodies specific for human B-lymphoma-derived Ig idiotypes (anti-ids) to determine the nature and extent of id/anti-id crossreactivity. The anti-id antibodies were prepared from Ig isolated from seven follicular center cell lymphomas by heterohybridoma technique. Thirty-six of 75 individual anti-ids obtained in this manner were further selected based on their reactivity with highly restricted or private idiotypic determinants. Twelve of the 72 (17%) lymphoma biopsies reacted with one or more of the 36 anti-ids that detect private determinants. A pool consisting of five individual antibodies would have detected 11 of the 12 crossreacting tumors. Staining of tumor cell populations was homogeneous in the positive cases, suggesting uniform idiotype expression. If there was a segregated staining pattern, it was generally related to the presence of CD3+ T cells in the section. These follicular center cell-derived anti-ids cross-reacted with follicular center cell tumors of all histologic grades with frequencies ranging from 13% to 50%. The structural basis for the crossreactivity of our lymphoma-derived private anti-ids is as yet not known. However, the reactivity of certain anti-ids with both kappa- and lambda-expressing tumors suggests a biased use of V gene segments in these crossreactive clones that is probably related to the VH gene. These data suggest the possibility that lymphoma may develop in a highly restricted pool of normal differentiated B cells or in B-cell subsets that express a limited repertoire of unmutated VH gene segments.

Animals↗
PubMed1992

Human spumavirus antibodies in sera from African patients.

Serum samples collected from patients with a wide variety of diseases from African and other countries were tested for antibodies to the human spumaretrovirus (HSRV). A spumaviral env-specific ELISA was employed as screening test. Out of 3020 human sera screened, 106 were found to be positive (3.2%). While the majority of patients' sera from Europe (1581) were negative, 26 were positive (1.6%). Sera from healthy adult blood donors (609), from patients with multiple sclerosis (48), Graves' disease (45), and chronic fatigue syndrome (41) were negative or showed a very low prevalence for spumaviral env antibodies. A higher percentage of seropositives (6.3%) were found among 1338 African patients from Tanzania, Kenya, and Gabon. Out of 1180 patients from Tanzania, 708 suffered from tumors, 75 from AIDS, and 128 had gynecological problems; 51 of the Tanzanian patients were HSRV seropositive (4.3%). A particularly high percentage of 16.6% seropositives were identified among nasopharyngeal carcinoma patients (NPC) from Kenya and Tanzania consistent with results reported 10 years ago. However, 20 nasopharyngeal carcinoma patients from Malaysia were HSRV-seronegative. In selected cases, sera from seropositive individuals were reacted with proteins from HSRV-infected cells in vitro. HSRV env- and gag-specific antibodies were specifically detected by these sera in Western blots. The results indicate spumavirus infections in human patients with various diseases at a relatively low prevalence worldwide; in African patients, however, the prevalence of spumavirus infections is markedly higher.

Africa↗
PubMed1992

T-cell lymphoma in Singapore: pathology, clinical findings and association with HTLV-1 antibodies.

Of 128 cases of malignant lymphomas studied in Singapore between 1986 and 1988, 28 were identified as peripheral T-cell lymphomas. Sera from two of the 128 cases were positive for HTLV-1 antibodies and both cases had the clinical and pathological features of adult T-cell leukaemia/lymphoma. The pathological and clinical features of the 28 cases of peripheral T-cell lymphoma are presented in detail. Survival data indicated no significant difference between the low grade and high grade histological types. Three of the patients had previous or concomitant malignancies. The percentage of T-cell lymphomas associated with HTLV-1 infection in Singapore is low compared to those areas in which HTLV-1 is endemic.

Adolescent↗
PubMed1992

Studies to determine the basis for hyperkalemia in recipients of a renal transplant who are treated with cyclosporine.

Hyperkalemia is commonly encountered in patients who receive a renal transplant and the immunosuppressive drug, cyclosporine. There is also a high incidence of hypertension (which is thought to be due to expansion of the extracellular fluid volume) and hyperchloremic metabolic acidosis in this group of patients. This constellation of findings led to the suspicion of the possibility that their basis might be type II hypoaldosteronism. To test this hypothesis, 12 patients with hyperkalemia (plasma K+, 5.1 +/- 0.2 mmol/L at the time of study) while receiving cyclosporine were studied. Patients who had diabetes mellitus, those receiving drugs known to cause hyperkalemia (e.g., beta blockers, angiotensin-converting enzyme inhibitors, K(+)-sparing diuretics), or those with a serum creatinine greater than 200 mumol/L were excluded. The renal response to hyperkalemia was inappropriate because the transtubular K+ concentration gradient (TTKG) was only 4.3 +/- 0.4 compared with a TTKG of 13 +/- 1, 2 h after 50 mmol of KCl was given to normal subjects. The TTKG, after administration of 200 micrograms of fludrocortisone, was still very low (5.6 +/- 0.6) in the patients compared with that of controls (12 +/- 1). After administration of 250 to 500 mg of acetazolamide to increase the delivery of bicarbonate to the distal nephron, the TTKG rose significantly to 11 +/- 1 in patients on cyclosporine, compared with 17 +/- 1 in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetazolamide↗
PubMed1991

[Prenatal diagnosis of albinism].

Prenatal diagnosis of oculocutaneous albinism (OCA) was made in 1 of 6 pregnancies at risk examined during the 20th week of gestation. A skin biopsy was taken from the fetal scalp under ultrasonic screening. Light and electron microscopy studies were performed in each case to demonstrate melanin pigment and melanosomal development in the melanocytes of the hair bulbs and the epidermis. In 1 fetus albinism was diagnosed by the absence of melanin pigment and by the demonstration that melanosomes were only present in stages I and II. In the other 5 fetuses melanin pigment and mature melanosomes (up to stage IV) were demonstrated. The pregnancy with the albino fetus was interrupted and the diagnosis of OCA was confirmed at autopsy.

Albinism, Oculocutaneous↗
PubMed1991

Prevention of hemodialysis subclavian vein catheter infections by topical povidone-iodine.

Subclavian catheter (SCC) related infections are a major cause of morbidity in hemodialysis patients, the vast majority due to staphylococci species. Povidone-iodine (PI) has proven anti-staphylococcal activity. Therefore, a randomized controlled trial of topical PI ointment was undertaken to evaluate the impact of this prophylactic intervention on the incidence of SCC related infections in hemodialysis patients. The role of S. aureus nasal carrier state in the acquisition of infection was also evaluated. Patients requiring SCC for temporary hemodialysis access were randomized to receive the treatment (T; N = 63) or sterile gauze dressings alone (C; N = 66). Catheter duration ranged from 2 to 210 days in both groups, with a mean of 38.6 days in T and 36.2 days in C (NS). Exit site (ES) infections were significantly less in T (5%) versus C (18%) (P less than 0.02); tip colonization (TC) was 17% in T versus 36% in C (P less than 0.01), while the incidence of septicemia (S) was also significantly less in T (2%) versus C (17%; P less than 0.01). S. aureus nasal carriers were at a threefold higher risk of SCC related septicemia (0.009/day) than noncarriers (0.003/day; P less than 0.05). The beneficial effect of PI ointment was most evident in this high risk group of S. aureus carriers: ES = 0% T versus 24% C, TC = 12% T versus 42% C, S = 0% T versus 29% C, P less than 0.05. There were no adverse effects of the treatment. The routine application of topical PI ointment to temporary hemodialysis catheter exit sites is effective in reducing SCC related infections.

Acute Kidney Injury↗
PubMed1991

Comparative analysis of health risk assessments for municipal waste combustors.

Quantitative health risk assessments have been performed for a number of proposed municipal waste combustor (MWC) facilities over the past several years. This article presents the results of a comparative analysis of a total of 21 risk assessments, focusing on seven of the most comprehensive methodologies. The analysis concentrates on stack emissions of noncriteria pollutants and is comparative rather than critical in nature. Overall, the risk assessment methodologies used were similar whereas the assumptions and input values used varied from study to study. Some of this variability results directly from differences in site-specific characteristics, but much of it is due to absence of data, lack of field validation, lack of specific guidelines from regulatory agencies, and reliance on professional judgment. The results indicate that carcinogenic risks are more significant than chronic non-carcinogenic risks. In most instances polychlorodibenzodioxins, polychlorodibenzofurans, and cadmium contribute more significantly to the total carcinogenic risk from MWC stack emissions than other contaminants. In addition, the contribution to total risk of all indirect routes of exposure (ingestion and dermal contact) exceeds that of the direct inhalation route for most studies reviewed.

Animals↗
PubMed1990

HTLV-I antibody studies in villagers in East Sepik Province, Papua New Guinea.

Serum samples collected in 1984 during a malariometric survey of two villages in the East Sepik Province of Papua New Guinea were tested for antibodies to HTLV-I. None of the villagers showed any symptoms suggestive of retrovirus infection. Eighteen of the 186 (9.5%) sera tested at that time were found to be positive. Blood samples were subsequently obtained from fifteen of the eighteen positives and subjected to analysis by enzyme-linked immunosorbent assay (ELISA), radioimmuno assay (RIA), radioimmunoprecipitation assay (RIPA), and Western blot (WB). Fourteen of the fifteen gave a positive ELISA response, but none were unequivocally positive by p 24 RIA. All sera tested were reactive to gag antigens by WB, but gave "indeterminate" results currently accepted criteria. Notably absent from the WB profiles of all of the study subjects was an antibody response to HTLV-I envelope protein gp 46. It is possible that these antibody responses are directed against a variant of HTLV-I or to a novel retrovirus which possesses core antigens similar to those of HTLV-I but has different envelope antigens. Until a virus is isolated, or the viral genome is identified in infected lymphocytes, the possibility remains that the response may be due to factors unrelated to retrovirus infection.

Adult↗
PubMed1979

The analysis of a temperature-sensitive (ts) mutation influencing the expression of heat shock-inducible genes in Drosophila melanogaster.

The effect of a ts-mutation belonging to the cell-lethal type on protein and RNA synthesis under heat shock conditions has been investigated. The mutation studied, l(l)ts-403, localized in the X-chromosome has significant effect on the kinetics of protein synthesis in salivary gland subjected to heat treatment under in vivo and in vitro conditions. The animals homozygous for l(l)ts-403 are characterized by a rapid drop of label incorporation into heat shock proteins. It is shown that the mutation affects not only the kinetics of heat-shock proteins synthesis but their electrophoretic pattern as well. The experiments performed enable us to conclude that the presumptive regulatory gene realized its action at the level of transcription of heat shock loci.

Animals↗
PubMed1978

Modern psychiatry in a general hospital.

An analysis of 3526 patients referred to the psychiatric unit of a general hospital from 1 January 1975 to 31 December 1977 is presented. The method of classification used was that of the revised Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association and the 8th revision of the International Classification of Diseases. A striking feature of this survey was the low prevalence of schizophrenia (9,8%). A noticeable trend was that more patients seemed to have less incapacitating psychiatric conditions. An exciting new facet of psychiatry is the increasing number of patients without apparent psychiatric illness who are referred to the unit. These include patients referred by colleagues for preliminary screening before organ transplantation, sex change operations, cosmetic surgery, sterilization and termination of pregnancy. Recommendations are made with regard to the role of psychiatric units in general hospitals.

Humans↗
PubMed1978

Heat-shock DNA homology in distantly related species of Drosophila.

Polytene chromosomes of D. melanogaster and D. virilis were hybridized in situ with 125I labeled mRNA isolated from polysomes of D. melanogaster tissue culture cells incubated at 37 degrees C. 125I mRNA hybridized preferentially with subdivisions 87A and 87Cl of the D. melanogaster 3R chromosome; grains were also observed at regions 93D, 95D and over the chromocenter. A considerable cross hybridization of this mRNA with D. virilis polytene chromosomes was observed. The 29C region of the D. virilis second chromosome was the main site of hybridization. Significant grain numbers also appeared in region 20F of the same chromosome. The two regions mentioned belong to heat shock loci in the latter species. Based on label intensity we conclude that region 29C of D. virilis contains DNA sequences retaining molecular homology with those at subdivisions 87A and 87Cl of D. melanogaster. SDS-polyacrylamide gel electrophoresis revealed similar distributions of heat shock proteins in the two species studied.

Animals↗
PubMed1978

The use of chlorazepate for premedication on the night before surgery.

Chlorazepate, a long-acting benzodiazepine, allayed anxiety before operation, being superior to placebo in a double-blind study in which the drug was given the night before surgery. Long-term relief of apprehension before surgery by the administration of chlorazepate, combined with a narcotic analgesic when indicated, is advocated.

Adult↗