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Biomedical subjects

R L Bernstein

Publications and source records attributed to R L Bernstein.

17 recordsLinked to original sources
PubMed1992

Classification of amok in DSM-IV.

Culture-bound syndromes have been described worldwide in many individuals and, for certain syndromes, in epidemic proportion, yet these disorders have been classified as rare and exotic conditions warranting minimal attention. Development of the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders and the tenth edition of the International Classification of Diseases offers an opportunity for providing a more sophisticated classification of these phenomena. The authors examine amok, a syndrome first described in Malaysia that consists of homicidal frenzy preceded by a state of brooding and ending with somnolence and amnesia. They discuss the concept of and criteria for a culture-specific disorder and propose that amok be classified as a culture-specific explosive behavioral disorder in DSM-IV.

Antisocial Personality Disorder↗
PubMed1991

Immunodominant carbohydrate determinants in the multicellular stages of Dictyostelium discoideum.

Two families of glycoprotein are defined in Dictyostelium discoideum by the presence of different glycoconjugates, both of which are highly immunogenic in mice. The previously described monoclonal antibodies MUD50 and MUD62 recognize the glycoconjugates and identify the respective glycoprotein families. Both types of glycosylation occur on vegetative and developmentally regulated glycoproteins. The immunodominant components of both families are reportedly O-linked sugars, but Western blots do not identify any glycoprotein that has both O-glycans, suggesting that there are two independently processed types of O-linked glycosylation in D. discoideum. The synthesis of the two O-glycan families is affected by glycosylation-defective mutations. Strains with a mutation at the modB locus lack one of these glycosylation types (that recognized by MUD50) and this mutation alters the size of two minor glycoproteins in the second family. Two new mutants, HU2470 (mod-352) and HU2471 (mod-353), lack the epitope recognized by MUD62. The two mutations map to different chromosomes. The mod-353 mutation also affects the size of PsA, a cell surface glycoprotein carrying the modB-dependent O-glycan.

Animals↗
PubMed1990

Burkitt's lymphoma and the role of Epstein-Barr virus.

Burkitt's lymphoma is the most common childhood cancer in Africa. Most prevalent in areas endemic for malaria, the disease, a malignant growth of lymphoid tissue, usually presents itself as a large tumour of the jaw. When first characterized in the 1950s, the lymphoma was thought to spread by some infectious agent. Subsequent research indicates that the frequent involvement of an infectious agent is but one factor in a more complex aetiology. Today, Burkitt's lymphoma is considered an example of multistep carcinogenesis. Each step in the process results from a different agent. The agent in the first step is the Epstein-Barr virus, which infects B cells of the immune system causing a proliferation of these cells. The second step, malarial infection, furthers the proliferation of B cells providing a large population of cells available for a chromosomal translocation which represents the third step in the formation of the lymphoma. The chromosomal translocation places a cancer causing gene, c-myc, in close proximity to an active antibody-encoding its proliferation resulting in a cell capable of unlimited growth which serves as the nucleus of a B cell lymphoma.

Burkitt Lymphoma↗
PubMed1990

Koro: proposed classification for DSM-IV.

Koro, a culture-specific disorder consisting of complaints of genital retraction and fear of death associated with genital retraction, has been recognized in Asian cultures in single cases and in epidemic proportions. Koro has been described in non-Asian patients as well, leading to debate concerning the true nature of the syndrome. The authors review past attempts to define and classify koro and present a classification for DSM-IV that they believe could be used to classify other culture-bound syndromes as well.

Adult↗
PubMed1990

A controlled clinicopathologic study of myocardial fibrosis in systemic sclerosis (scleroderma).

Clinicopathologic correlations of myocardial fibrosis were examined in 54 autopsied patients with scleroderma and 54 age and sex matched autopsy controls. Thirty eight (70%) of the patients with scleroderma had myocardial fibrosis compared to 20 (37%) of the controls (p less than 0.005). There was no significant difference in the prevalence of contraction band necrosis in the patients with scleroderma (22%) compared to controls (17%). Patients with scleroderma with left ventricular dysfunction in the absence of other causative factors clinically had a greater prevalence of both advanced myocardial fibrosis (60%) and contraction band necrosis (40%) than did the other patients with scleroderma or the controls. We conclude that patients with scleroderma with the greatest likelihood of advanced myocardial fibrosis can be identified clinically, and their findings are consistent with the presence of microvascular coronary vasospasm, a "myocardial Raynaud's phenomenon."

Adult↗
PubMed1989

Overlapping redundant septuplets identical with regulatory elements of HIV-1 and SV40.

Overlapping redundant short oligomers in DNA sequences of retroviruses and papovaviruses have been identified. For each sequence, a search procedure determines the 5% short oligomers of the same length with the highest ratios of observed to expected occurrences based on singlet composition of the sequence. These short oligomers are referred to as compositionally-assessed redundant sequence elements (COARSEs). A pair of COARSEs overlapping by at least one base is considered to be a COARSE overlap. Most COARSE overlaps of the 7th order (overlapping septuplets) are found in long terminal repeats of retroviruses and in the regulatory control regions of papovaviruses SV40, BK and JC. Many of the 7th order COARSE overlaps in HIV-1 and SV40 are identical with regulatory elements determined experimentally. On the contrary, very few of the most frequently occurring oligomer overlaps, which are defined differently from COARSE overlaps, are present in the regulatory regions of retroviruses and papovaviruses. Examining DNA sequences of other genomes by the COARSE overlap method may identify putative regulatory regions.

Base Sequence↗
PubMed1989

Flow cytometric analysis of mature adipocytes.

Flow cytometry is an excellent method for studying the physiological function in adipocytes because their response to hormones, especially insulin, varies with cell maturity and therefore size. Adipocytes present a unique technical challenge. A freshly prepared adipocyte suspension contains cells and fat droplets ranging from 10 to greater than 120 microns in diameter. Stored fat occupies 90-98% of the cell volume, making it difficult to distinguish cells from fat droplets. Other difficulties include buoyancy, large size, fragility, and tendency to aggregate and clog the sample tube and nozzle. These obstacles were overcome by 1) maintaining the sample, sample line, sheath fluid, reservoir, and nozzle assembly at 37 degrees C; 2) using a 200 microns diameter orifice; 3) using a short, 300 microns inside diameter Teflon sample delivery line; 4) injecting the sample at constant flow rate into the sheath fluid at low pressure; and 5) using the pH-sensitive vital stain, biscarboxyethylcarboxyfluorescein (BCECF) to distinguish cells from fat droplets. Stained cells are brightly fluorescent when excited at 488 nm. Because fat droplets do not fluoresce, they can be distinguished from fat cells by gating on the BCECF emission. The cytosolic pH of intact, viable, mature adipocytes was derived from the ratio of the fluorescent emission intensities at 520 and 620 nm and was estimated to be 7.2. Unlike BCECF, several other useful fluorescent probes of cell function, e.g., the intracellular calcium indicator, indo-1, label both fat cells and fat droplets.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1988

Detergent treatment of Dictyostelium discoideum cells allows examination of internal cell type-specific antigens by flow cytometry.

Monoclonal antibodies are used extensively in flow cytometry to identify subpopulations of cells differing in surface antigens. Conventional studies on living cells do not allow analysis of internal antigens, because antibody molecules do not pass through an intact plasma membrane. It is important for developmental studies on Dictyostelium discoideum that not only surface but also internal antigens be analysed. Here techniques are reported that make possible such studies by permeabilising cells with mild detergent treatments using digitonin. Flow cytometer profiles of unfixed cells show that antigens recognised by two monoclonal antibodies, MUD102 and MUD3, are found inside subpopulations of cells in the D. discoideum slug. Double-labelling experiments were carried out to demonstrate that the antigens recognised by these antibodies are present inside prespore but not prestalk cells. The detergent treatment leads to loss of forward-angle light scatter, but 90 degrees light scatter of cells is not greatly affected. While fixed cells sometimes gave satisfactory results, internal labelling did not reliably demonstrate the two subpopulations observed with unfixed cells.

Animals↗
PubMed1988

Fluorocarbon-enhanced mutagenesis of polyaromatic hydrocarbons.

The widely used fluorocarbon refrigerant and cleaning solvent 1,1,2-trichloro-1,2,2-trifluoroethane (Freon TF), though generally considered biologically inert, enhances the metabolic activation of chemical carcinogens. Liver microsomal extracts from mice given single intraperitoneal injections of this fluorocarbon showed significant increases in their ability to activate carcinogenic polyaromatic hydrocarbons to form mutagens, compared to control mice injected with saline. Polyaromatic hydrocarbons aminofluorene and acetylaminofluorene were activated in this way. Mutagenicity was measured by a microbial assay. Both commercial grade and redistilled fluorocarbons gave similar results, that is, more highly active liver extracts after administration of the fluorocarbon preparation to mice. Neither industrial grade nor redistilled preparation was itself mutagenic. A combined liver microsomal extract from mice breathing Freon TF at 20,000 ppm in air for 8 hr also had enhanced ability to activate aminofluorene as a mutagen. Exposing mice to Freon TF by inhalation more closely matches the normal route of human exposure to fluorocarbons. The results of this study imply that low-molecular-weight fluorocarbons may pose a carcinogenic risk by acting as cocarcinogenic enhancers of carcinogen activation. The possibility that fluorocarbons are cocarcinogens in this way has apparently not been heretofore considered.

Administration, Inhalation↗
PubMed1987

Early and late forms of cyclosporine nephrotoxicity: studies in cardiac transplant recipients.

To characterize the two forms of cyclosporine nephrotoxicity, we examined renal function in the immediate and late postoperative periods after cardiac transplantation. Moderate azotemia occurred during the first postoperative week in 58% of 43 cyclosporine-treated recipients, but in only 34% of 41 azathioprine-treated recipients, and 4% of 25 patients undergoing cardiopulmonary bypass for nontransplant surgery (both P less than .01 v cyclosporine). Acute renal failure developed in an additional 12% of the cyclosporine-treated group. Late postoperative renal dysfunction also occurred with a high prevalence. Life-table analysis indicated that at 6 months 55%, at 12 months 17%, at 24 months 4%, and at 36 months no cyclosporine-treated recipients retained normal renal function. Three renal biopsies performed in subjects with late nephrotoxicity demonstrated prominent interstitial fibrosis. Although one patient subsequently required chronic dialysis, reduction of cyclosporine dosage from a mean of 5.3 +/- 0.7 mg/kg/d to a mean of 2.3 +/- 0.3 mg/kg/d 9 to 21 months after transplantation with concurrent initiation of azathioprine therapy to prevent rejection led to an improvement of renal function in the five patients so treated. These data indicate that there are two distinct forms of cyclosporine nephrotoxicity. Although both occur with high prevalence, the early form does not appear to be a specific risk factor for the late form.

Acute Kidney Injury↗
PubMed1985

Long-term hemodynamic follow-up of cardiac transplant patients treated with cyclosporine and prednisone.

To evaluate the long-term hemodynamic results in cardiac transplant patients treated with cyclosporine and prednisone, 19 patients were studied by cardiac catheterization and endomyocardial biopsy 13 +/- 3 months after transplantation. Immunosuppression consisted of 6 +/- 4 mg/kg/day cyclosporine and 20 +/- 8 mg/day prednisone. Eighteen patients were asymptomatic but had developed postoperative systemic hypertension (17 on antihypertensive therapy). These patients were compared with a normotensive control group of 18 patients without cardiovascular disease. Significant differences were found in heart rate; right atrial, pulmonary arterial, pulmonary arterial wedge, systemic arterial, and left ventricular end-diastolic pressures; cardiac index and stroke volume index; systemic and pulmonary vascular resistance; and end-diastolic volume index and left ventricular ejection fraction. The most frequent hemodynamic abnormalities included an elevated arterial pressure in 10 patients (56%), an elevated left ventricular end-diastolic pressure in six patients (33%), and a reduced ejection fraction in five patients (28%). Hemodynamic abnormalities tended to resolve or improve in the five patients restudied 2 years after transplantation. There was no significant relationship between fibrosis or inflammation on endomyocardial biopsy and hemodynamic abnormalities. We conclude that mild-to-moderate hemodynamic abnormalities are common in asymptomatic cardiac transplant patients receiving cyclosporine and prednisone.

Adult↗
PubMed1981

Extracellular folate deaminase of Dictyostelium discoideum.

Folate deaminase released from cells of Dictyostelium discoideum is heterogeneous with respect to molecular weight and stability at 60 degrees C. The most heat-stable component isoelectrofocuses in a broad band at approx. pH 6. The Km value of this component for folate is approx. 7 x 10(-7)M and Mr approx. 40 000. The major portion if not all of the deaminase binds to immobilized concanavalin A and lentil lectin. Extracellular folate deaminase has a pH-optimum of approx. pH 6.0. This is higher than that of lysosomal enzymes, which are also glycoproteins released into the extracellular medium.

Aminohydrolases↗
PubMed1981

Folate deaminase and cyclic AMP phosphodiesterase in Dictyostelium discoideum: their regulation by extracellular cyclic AMP and folic acid.

Cyclic AMP and folic acid act as chemotactic factors in Dictyostelium discoideum. Both agents, when applied extracellularly, also control cell development from the growth stage to the acquisition of aggregation competence. Cyclic AMP phosphodiesterase and folate deaminase are extracellular enzymes whose activity is regulated during early differentiation of D. discoideum cells. The two enzymes help control the extracellular levels of cyclic AMP and folic acid. The substrates cyclic AMP and folic acid each increase the extracellular activity of folate deaminase as well as phosphodiesterase. The specificity of extracellular phosphodiesterase regulation by cyclic AMP indicates that the effect is mediated by specific cyclic AMP receptors rather than the catalytic site of cell surface phosphodiesterase. To some extent cyclic AMP and folic acid are interchangeable with respect to regulating differentiation and enhancing enzymatic inactivation of intercellular signals. Thus the two extracellular signals may share a common cellular pathway of signal transduction. The regulation of folate deaminase and phosphodiesterase by folic acid does not always parallel the folic acid effects on development. Pulses of folic acid stimulate development of aggregation competence, whereas a continuous flux inhibits. In contrast, either continuous flux or pulses of folic acid increase the deaminase and phosphodiesterase activities.

3',5'-Cyclic-AMP Phosphodiesterases↗