Search PubMed⌕ Search

Biomedical subjects

H Bernstein

Publications and source records attributed to H Bernstein.

At least 55 records · Page 3Linked to original sources
PubMed1994

Calmodulin antagonists inhibit human immunodeficiency virus-induced cell fusion but not virus replication.

We have reported that amphipathic helical segments in the cytoplasmic domain of the HIV-1 envelope glycoproteins bind to calmodulin (CaM) with high affinity, and inhibit calmodulin-regulated proteins. To investigate the possible role of calmodulin activity in HIV-1 replication, we investigated the anti-HIV activity of various CaM antagonists--trifluoperazine and naphthalenesulfonamide W13 or W7--in HeLa T4 cells, PBMCs, and various T lymphocytic cell lines. The different CaM antagonists were found to inhibit the proliferation of the different cell types to varying extent. Also, the CaM antagonists were found to exert a greater antiproliferative effect on H9/HIV-1IIIB, as compared to uninfected H9 cells, suggesting a deficit of CaM function in HIV-infected cells. The CaM antagonists inhibited virus-induced cell fusion in HeLa T4 cells infected with a recombinant vaccinia virus expressing HIV-1 envelope proteins at threshold concentrations that do not inhibit cell proliferation. The fusion-inhibitory effects of the CaM antagonists were also observed in cocultures of HIV-infected (H9/HIV-1IIIB) and uninfected H9 cells. Under these conditions, the synthesis and surface expression of the viral glycoproteins were not affected, although the kinetics of processing of HIV envelope precursor was delayed. Virus production from both HIV-infected peripheral blood mononuclear cell (PBMC) and MT-2 cell cultures was inhibited by CaM antagonists at concentrations that were inhibitory to cell proliferation. Surprisingly, threshold concentrations of CaM antagonists that do not inhibit cell proliferation were found to enhance virus production from HIV-infected MT-2 cells, but not PBMCs.(ABSTRACT TRUNCATED AT 250 WORDS)

Calmodulin↗
PubMed1994

Dental implants.

Explore the source record for details and available documents.

Dental Implants↗
PubMed1993

Kinetics of immobilized heparinase in human blood.

Immobilized enzyme reactors can form the basis of useful blood detoxification systems. One such reactor was developed for heparin neutralization by immobilized heparinase. In this article, reactor kinetics were studied under clinically relevant conditions. Heparin neutralization was assessed in vitro in whole human blood using (a) a well-mixed batch reactor, and (b) an oscillating, continuous-flow reactor. The kinetics of heparin neutralization in human blood were first order over the entire range of heparin and enzyme concentrations and particle fractions tested. The kinetic rate was not sensitive to physiological variations in the concentration of antithrombin, a heparin binding protein in blood. Enzyme activity did not decrease significantly over the 2 hour test period. Kinetic control of the system with minimal intraparticle diffusional limitations was suggested by the Thiele moduli (0.11-0.67) and effectiveness factors (0.98 +/- 0.01). The ratio kcat/Km obtained in batch studies was 0.0028 +/- 0.0008 cm3/microgram-min. A continuous-flow oscillating reactor within a closed recirculation loop performed as a single well mixed batch reactor; there was a short mixing time of recirculating blood when compared to reaction time. A model based on this mixing pattern and the kinetics obtained in independent batch studies accurately predicted heparin neutralization profiles observed in the continuous-flow system.

Antithrombins↗
PubMed1993

Successful epidural anaesthesia for a patient with Takayasu's arteritis presenting for caesarean section.

The management of a 24-yr-old parturient with Takayasu's arteritis (TA) presenting at term for Caesarean section is discussed. The best anaesthetic management for the patient with TA is controversial, but avoiding regional anaesthesia has been suggested by some authors because of the risk of hypotension and the subsequent need for vasopressors. We report the use of regional anaesthesia in a term parturient with severe TA undergoing Caesarean section. Anaesthesia was provided with chloroprocaine 3%, via a lumbar epidural catheter. The initial doses of 60 mg and 150 mg were followed by a decrease in BP (from 110/70 to 70/40) which was corrected with iv fluids and ephedrine 25 mg. Additional doses of chloroprocaine, 150 and 90 mg, were uneventful. It is concluded that an epidural can be made in safety to provide anaesthesia for Caesarean section in patients with TA.

Adult↗
PubMed1992

Oxidative and other DNA damages as the basis of aging: a review.

DNA damages occur continuously in cells of living organisms. While most of these damages are repaired, some accumulate. In particular, there is evidence for DNA damage accumulation in non-dividing cells of mammals. These accumulated DNA damages probably interfere with RNA transcription. We consider that the decline in the ability of DNA to serve as a template for gene expression is the primary cause of aging. Oxidative DNA damages are among the best documented and prevalent DNA damages and are likely to be a prominent cause of aging.

Aging↗
PubMed1991

The pharmacokinetics of, and humoral responses to, antigen delivered by microencapsulated liposomes.

The feasibility of creating a s.c. depot for sustained protein delivery with the goal of enhancing antigen immunogenicity was investigated. The depot was designed as antigen-laden liposomes of hydrogenated egg phosphatidylcholine and cholesterol (1:1 molar ratio) encapsulated in alginate-poly(L-lysine) microcapsules and evaluated using iodinated bovine serum albumin (BSA) as a model antigen. The in vivo release behavior of the liposomes and microencapsulated liposomes (MELs) was evaluated from the BSA serum concentration profiles after s.c. injection into rats and the pharmacokinetic parameters of 125I-labeled BSA appearance after s.c. or i.v. injections of BSA in saline. Maximal BSA concentrations were detected 11 h after s.c. injection in all rats. The BSA serum concentrations decreased rapidly in rats injected with BSA in saline or Freund's adjuvant and less rapidly in rats injected with BSA in liposomes or MELs. Four to 5 weeks after injection, BSA-associated radioactivity was detected only in sera of rats injected with BSA in liposomes or MELs. Fifty days after injection, 50% of the originally injected BSA was recovered form the s.c. sites of rats injected with BSA in MELs; no radioactivity was recovered from the other three groups of rats. The antigen-reactive antibody levels induced in rats immunized with BSA in MELs were 2- to 3-fold higher than those obtained in rats immunized with BSA in liposomes, saline, or Freund's adjuvant. More significantly, high antibody levels were maintained for more than 150 days after a single injection of BSA in MELs, suggesting that MELs can serve as a long-term single-dose immunization vehicle.

Animals↗
PubMed1991

To centralize or compete is not the issue at hand.

AR's November 1990 issue featured "Stripping the Myths of Merger-mania," by Frederick Thayer, Professor Emeritus, University of Pittsburgh's Graduate School of Public and International Affairs. The article is a provocative effort toward educating healthcare professionals, whose academic backgrounds have been rooted mainly to clinical and technological concerns, regarding the fundamental causes that have led to the current economic environment inside which we struggle to plot strategies to provide patient services on a more equitable basis for the majority of people. In this year's January issue, Herbert Bernstein, Professor of Economics at Drexel University's College of Business and Administration in Philadelphia responded to Thayer's experienced pondering of the why's, how's, and cumulative effect of corporate activity (mergers) on the ongoing well-being of the physical entity resulting from such stripping and learning. The March 1991 issue of AR gave vent to Thayer's subsequent rebuttal. Here, again, are thoughts from Bernstein and Thayer, offered with the intention of exposing AR readers to a perspective of the world a bit removed from acquisition or application of technology, but directly connected to the larger issues that "world leaders" and national policy makers are struggling to cope with. Underlying the thoughts of both Bernstein and Thayer is a desire to do their part to stimulate front line healthcare workers, physicians, and executive-level management to understand the forces at play in the ever-changing face of our economic structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Economic Competition↗
PubMed1990

Modification of DNA by bile acids: a possible factor in the etiology of colon cancer.

Bile acids have been implicated as promoters and cocarcinogens in the etiology of colon cancer and as comutagens and mutagens in bacteria. These observations suggest the hypothesis that bile acids may interact directly with DNA. We treated the single stranded circular DNA of phage M13 with bile acids and found that the transfection efficiency of this DNA declined up to a 1000-fold. This result suggests that bile acids can damage DNA and thus may play an important role in the etiology of colon cancer.

Bile Acids and Salts↗
PubMed1990

Colon cancer and dietary fiber: cellulose inhibits the DNA-damaging ability of bile acids.

Colon cancer is the second most common type of cancer in the United States. Bile acids have been implicated in the etiology of this disease. In a previous study, we showed that bile acids can damage DNA in vitro. In this study, we report that this damage is largely prevented when the bile acids are pretreated with cellulose fiber. Preliminary data show that cellulose may act as a catalyst to promote polyesterification of bile acid to a biologically inactive form.

Cellulose↗
PubMed1989

Chronic pruritic eruption in patients with acquired immunodeficiency syndrome associated with increased antibody titers to mosquito salivary gland antigens.

Five of seven patients with acquired immunodeficiency syndrome (AIDS) who had pruritus and a chronic, nonspecific-appearing skin eruption had increased antibody titers to antigens in the salivary glands of Aedes taeniorhynchus, a salt marsh mosquito common to South Florida. We hypothesize that the pruritus and skin lesions in patients with AIDS represent a form of chronic "recall" reaction. Increased antibody titers to mosquito salivary gland antigens may be a consequence of nonspecific B cell activation, a feature of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Stereotactic radiosurgery for fractionated radiation: a proposal applicable to linear accelerator and proton beam programs.

A stereotactic radiosurgery technique is described which allows stereotactic radiation therapy to be easily fractionated on a daily or weekly basis. This permits adequate and safe radiation therapy to lesions larger than 2.5 cm, such as large arteriovenous malformations, and possibly safer radiation to smaller lesions near crucial intracranial structures. The technique utilizes external scalp landmarks and avoids the need for standard stereotactic head devices.

Equipment Design↗
PubMed1989

Mosquito salivary gland antigens identified by circulating human antibodies.

Salivary glands were removed from female mosquitoes of laboratory-reared strains of species common to southern Florida. Protein antigens were isolated from homogenates of these glands by denaturing electrophoresis and transferred to nitrocellulose for immunoblotting with serum samples obtained from human volunteers. A spectrum of antigens with a wide range of molecular weights (14 to 126 kilodaltons) were identified by antibodies in human serum for each species. Both species-unique and species-shared antigens were present. The results of these studies indicate that the humoral response to mosquito bite is complex, with a multitude of antigens provoking antibody responses. Since each individual has his or her own unique exposure history to mosquitoes, it seems unlikely that desensitization to a specific immunogen will confer protection in clinical situations in which multiple exposures to a variety of mosquito species occur.

Animals↗
PubMed1988

Circulating antibody detection in human serum to mosquito salivary gland proteins by the avidin-biotin-peroxidase technique.

Serum was collected from individuals with little, average, or extensive exposure to mosquito bites for determination of the presence of circulating antibodies to mosquito salivary gland proteins. Intensity of exposure was determined by mosquito-bite and exposure history. Sections cut through the thorax of four different species of mosquitoes, locally prevalent in South Florida, were exposed to serum and developed for antibody binding with the use of the avidin-biotin-peroxidase immunohistochemical technique. In subjects with histories of little or average exposure to mosquitoes, binding was observed that appeared to be species-specific; in subjects with extensive exposures, little antibody binding to salivary gland was noted. We hypothesize that suppression of the humoral immune response is an adaptive mechanism in response to significant exposures of mosquito salivary gland antigens.

Animals↗
PubMed1988

Confirmation of early Kaposi's sarcoma by polyclonal antibody to type IV collagen.

By the use of polyclonal antibody to type IV collagen that binds to epitope(s) retained in routinely processed tissues, we have confirmed the presence of early Kaposi's sarcoma in skin lesions that were not diagnostic on histologic examination. This reagent is of considerable use, particularly in cases of rapidly developing Kaposi's sarcoma with acquired immunodeficiency syndrome in which histologic features may not be fully developed.

Antibodies↗
PubMed1988

Yeast gene RAD52 can substitute for phage T4 gene 46 or 47 in carrying out recombination and DNA repair.

The RAD52 gene of Saccharomyces cerevisiae and genes 46 and 47 of bacteriophage T4 are essential for most recombination and recombinational repair in their respective organisms. The RAD52 gene was introduced into expression vectors that were used to transform Escherichia coli. The expression of RAD52 was then induced, and the ability of RAD52 to complement phage mutants defective in gene 46 or 47 was determined with respect to the three criteria of phage growth, recombination, and recombinational repair. RAD52 gene expression was found to allow growth of gene 46 and 47 mutants under otherwise restrictive conditions, as measured by plaque formation and burst size. Expression of the RAD52 gene also restored the ability of gene 46 and 47 mutants to undergo recombination of rII markers. Furthermore, the RAD52 gene restored the ability of gene 46 and 47 mutants to undergo recombinational repair after UV irradiation. The published DNA sequence of gene RAD52 was compared with the published sequences of genes 46 and 47. Although overall sequence similarities were only marginally significant, RAD52 and gene 46 had substantial sequence similarity over a limited region.

Base Sequence↗