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Biomedical subjects

A Epstein

Publications and source records attributed to A Epstein.

17 recordsLinked to original sources
PubMed1992

The embryonically active gene, unkempt, of Drosophila encodes a Cys3His finger protein.

The unkempt gene of Drosophila encodes a set of embryonic RNAs, which are abundant during early stages of embryogenesis and are present ubiquitously in most somatic tissues from the syncytial embryo through stage 15 of embryogenesis. Expression of unkempt RNAs becomes restricted predominantly to the central nervous system in stages 16 and early 17. Analysis of cDNAs from this locus reveals the presence of five Cys3His fingers in the protein product. Isolation and analysis of mutations affecting the unkempt gene, including complete deletions of this gene, indicate that there is no zygotic requirement for unkempt during embryogenesis, presumably due to the contribution of maternally supplied RNA, although the gene is essential during post-embryonic development.

Amino Acid Sequence↗
PubMed1991

Plasmid vectors for selecting IS1-promoted deletions in cloned DNA: sequence analysis of the omega interposon.

We have constructed two plasmid vectors which allow selection for in vivo deletions within cloned DNA fragments. The plasmids are derivatives of pBR322 which carry the Escherichia coli rpsL (strA) gene, known to confer a dominant streptomycin (Sm)-sensitivity phenotype to the host cell, and a copy of the IS1 transposable element. Sm-resistant strains that harbor these plasmids display sensitivity to Sm. Spontaneous IS1-promoted deletions across the rpsL gene can be isolated simply by selection for Sm resistance. Hence, nested sets of deletions of a cloned DNA can be obtained and sequenced with an IS1-specific primer. Using this approach, we have determined the complete nucleotide sequence of the omega interposon [Prentki and Krisch, Gene 29 (1984) 303-313].

Amino Acid Sequence↗
PubMed1991

Technetium-99m-labeled proteins for imaging inflammatory foci.

Polyclonal human IgG (IgG), antinuclear antibody (TNT-1), and human serum albumin (HSA), were labeled with 99mTc by a method recently developed in our laboratory, and administered i.v., each to a separate group of five mice, bearing inflammatory foci induced by an i.m. injection of 40 microL turpentine or 5 x 10(8) E. coli and 5 x 10(8) Entercocci. TNT-1 labeled with 125I served as a control and 67Ga-citrate as a "gold standard". At 4 or 24 h post injection, animals were imaged and sacrificed for tissue distribution studies. At 4 h in the turpentine group, the abscess-to-muscle ratios were: 67Ga, 4.8 +/- 2.1, 125I-TNT-1, 4.3 +/- 1; 99mTc-TNT-1, 3.5 +/- 1.8; 99mTc-IgG, 3.9 +/- 0.6; and 99mTc-HSA, 4.3 +/- 1. In the microorganism group, these ratios were 2.6 +/- 0.6, 3.3 +/- 0.5, 3.4 +/- 0.08, 3 +/- 1.1 and 4.1 +/- 0.6, respectively. Autoradiographic examination of infected tissues indicated that leakage of labeled proteins into interstitial space due to increased capillary permeability may be one of the major mechanisms of uptake.

Animals↗
PubMed1991

Segmentally restricted, cephalic expression of a leucine zipper gene during Drosophila embryogenesis.

The expression pattern and DNA sequence of a newly identified gene, CNC (cap'n'collar), suggest a role for this gene in cephalic patterning during Drosophila embryogenesis. In situ hybridization reveals transcripts localized to the mandibular segment and the hypopharyngeal and labral primordia first detectable in late blastoderm stages. Sequence analysis of cDNA clones from the CNC locus shows the CNC gene product to be related to transcription factors of the leucine zipper (bZIP) class. Based on its protein sequence, we propose that CNC is a subunit of a heterodimeric regulatory protein involved in the control of head morphogenesis.

Amino Acid Sequence↗
PubMed1991

Working group recommendations: research on content and efficacy of geriatric evaluation and management interventions.

Methods of conducting comprehensive geriatric evaluation and management (GEM) are proliferating in a variety of clinical settings. However, rigorous evaluations of efficacy for this new approach to care of older patients have demonstrated a favorable impact on patient outcome in only a few studies. All of these have been controlled single site studies, and replication is needed. If replication studies show similar results, further studies should be undertaken to define the minimum necessary intervention to achieve the desired outcome. Controlled trials are needed to determine if consultative geriatric evaluation and/or primary patient management is effective. Further innovative work is needed in model development for geriatric assessment and management in outpatient settings. Finally, studies of geriatric evaluation and management in other environments, such as home care or the nursing home, are recommended.

Forecasting↗
PubMed1991

Haemodynamic and electrophysiological effects of amlodipine, a new long-acting calcium antagonist.

Patients with stable angina pectoris received an intravenous bolus injection of 10 mg amlodipine followed by a second 10-mg bolus, 30 min later, if no haemodynamic compromise occurred. Systolic and diastolic blood pressures were significantly reduced and cardiac output increased. Left ventricular function was unaltered. Amlodipine did not affect the electrophysiological parameters studied; sinus node recovery time and the pacing rate to Wenckebach heart block did not significantly change from baseline. Amlodipine is a powerful arterial vasodilator with no negative inotropic effects. Cardiac electrophysiological function is not affected by amlodipine.

Adult↗
PubMed1990

Temporary amelioration of hyperlipidemia in low density lipoprotein receptor-deficient rabbits transplanted with genetically modified hepatocytes.

Familial hypercholesterolemia is an inherited disease in humans that is associated with coronary artery disease and is caused by a deficiency of the receptor that mediates the internalization of low density lipoprotein (LDL). We have used an animal model for familial hypercholesterolemia, the Watanabe heritable hyperlipidemic (WHHL) rabbit, to design a therapeutic approach for this disease, which attempts to correct the hepatic defect in LDL receptor expression. Hepatocytes were harvested from WHHL rabbits, plated in primary cultures, and exposed to recombinant retroviruses capable of efficiently transferring a functional human LDL receptor gene. Genetically modified cells were harvested and infused into the portal vein of WHHL recipients, who were analyzed for metabolic consequences of human LDL receptor expression. Each animal exhibited a statistically significant decrease in total serum cholesterol 2-6 days after transplantation, with an eventual return to pretreatment levels. Proviral DNA sequences and virus-directed transcripts were detected in liver tissue 24 hr after transplantation. In situ hybridization demonstrated provirus expression in a small population of hepatocytes distributed in periportal sections of the liver. This study illustrates the potential of somatic gene therapy in ameliorating hyperlipidemia associated with familial hypercholesterolemia.

Animals↗
PubMed1989

Immunohistochemical analysis of non-Hodgkin's lymphomas with the monoclonal antibody to follicular center lymphocytes reactive in paraffin sections.

The monoclonal antibody designated LN-1 was used in an attempt to identify the antigen in follicular center cell lymphomas using tissue sections fixed in formalin. The LN-1 antibody has been shown in previous studies to identify follicular center cells and give reproducible results in tissue fixed in B5. We used the ABC peroxidase technique to examined formalin-fixed, paraffin embedded sections representing 52 cases of various histologic subgroups of non-Hodgkin's lymphomas based upon the Lukes-Collins classification. Following immunostaining with LN-1 using overnight incubation of the antibody and papain treated sections, 37 cases, and all of the 38 cases previously diagnosed as follicular center cell lymphomas, gave a positive reaction to the LN-1 monoclonal antibody.

Antibodies, Monoclonal↗
PubMed1985

Monoclonal antibodies reactive with B-lymphocytes and histiocytes in paraffin sections.

Representative sections of normal lymph nodes, cases of reactive lymphadenopathy, and Hodgkin's disease were examined using two monoclonal antibodies reactive in paraffin sections using an immunoperoxidase technique. Antibody LN-1 recognizes B-lymphocytes in follicles; antibody LN-2 recognizes a broader spectrum of B-cells, and also shows positivity with some monocytes/histiocytes. The pattern of immunostaining with these antibodies is described with particular reference to Hodgkin The pattern of immunostaining with these antibodies is described with particular reference to Hodgkin and Reed-Sternberg cells. Some of the implications are discussed.

Antibodies, Monoclonal↗
PubMed1978

Speech audiometry.

Two aspects of speech audiometry, namely, the speech reception threshold and the speech discrimination scores, have been discussed in the light of their development and present day administration. Evidence was presented to forego the concept of phonetic balance in discrimination test messages for the preferable attributes of familiarity and equated list difficulty. Campbell's redistribution of the W-22 word lists was proposed as an available solution to one of these parameters. Some delineation of the single "maximal" discrimination score's relation to the prediction of the hearing impaired individual's ability to understand continuous discourse was offered. Diagnostic implications of speech audiometry were not treated.

Audiometry↗
PubMedDate not supplied

Herpes simplex type 1 activation by Epstein-Barr virus nuclear antigen 1.

We have investigated the effect of Epstein-Barr virus nuclear antigen 1 (EBNA-1), a nuclear protein encoded by EBV, on herpes simplex virus type 1 (HSV-1) infection either in cells constitutively expressing EBNA-1 or in transient expression assays. Rat-1 cells and rat embryo fibroblasts (REF) immortalized by c-myc or E1A were transfected with a specific EBV DNA fragment coding for EBNA-1. Cloned cell lines which constitutively expressed this antigen were infected with HSV-1. Our results indicate that in EBNA-1-expressing cells, virus growth was higher than in control cells for different virus strains or rodent cell lines. This increase was maximal when cells were infected at low multiplicity, as determined by virus growth, and correlated with the stimulation of viral DNA synthesis. REF + c-myc and Vero cells were cotransfected by an EBNA-1 expression vector driven by Moloney murine leukaemia virus LTR and HSV-1 immediate-early (alpha 0) or early thymidine kinase upstream promoter regulatory regions linked to chloramphenicol acetyltransferase (CAT) coding sequences as effectors. In both cell lines, stimulation of CAT expression by EBNA-1 was observed only with the immediate-early promoter. These results suggest that EBNA-1 can transactivate immediate-early HSV-1 expression.

Animals↗
PubMedDate not supplied

Earmold configuration: relation to speech discrimination scores.

Choice of the earmold for a particular individual is perhaps the most subjective of all decisions made by clinicians in hearing aid fitting. The four earmold designs used in this study were standard-long, standard-short, belled-vented, and cavernous. Conslusions were: 1) performance differences in earmolds of contrasting design can be assessed by discrimination scores with monosyllabic word lists of equal difficulty; 2) among the physical measures taken of the earmold-receiver systems, frequency-response overall range (HAIC) ranked the devices in agreement with group responses to a word identification task; and 3) these data offer a basis for endorsement of the standard-long and cavernous-short earmold types over the other two with their superiority evident in each of the discrimination categories of excellent, good, and poor.

Acoustic Impedance Tests↗