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Biomedical subjects

M Strand

Publications and source records attributed to M Strand.

At least 37 records · Page 2Linked to original sources
PubMed1990

Identification of a decapeptide region of human interferon-alpha with antiproliferative activity and homology to an immunosuppressive sequence of the retroviral transmembrane protein P15E.

We have identified a 10-amino acid sequence (amino acid, 9-18) from interferon-alpha (IFN-alpha) that when presented as a synthetic peptide inhibits both the proliferation of the Daudi lymphoblastoid cell line and the antigen receptor-stimulated proliferation of fresh human T lymphocytes. This sequence, which was identified by virtue of its sequence similarity (70% identity) to the immunosuppressive sequence of the retroviral transmembrane protein p15E, represents the smallest fragment of IFN-alpha that has been shown to date to be biologically active.

Amino Acid Sequence↗
PubMed1990

Inhibition of lymphoproliferation and protein kinase C by synthetic peptides with sequence identity to the transmembrane and Q proteins of visna virus.

A peptide sequence in the transmembrane protein of visna virus has been identified that bears a high degree of similarity to a sequence within the transmembrane protein gp41 of human immunodeficiency virus that we have previously shown to be immunosuppressive. Also within the Q (vif/sor) open reading frame of the visna virus genome is a sequence that is highly similar to the immunosuppressive sequence from the retroviral transmembrane protein p15E. We synthesized peptides containing these visna virus sequences and tested them for immunosuppressive activity, comparing them with their human immunodeficiency virus and leukemia retrovirus counterparts. Both the Q- and transmembrane-derived visna virus peptides inhibited lymphoproliferation stimulated by either interleukin-2 or the T-cell antigen receptor in a dose-dependent and sequence-specific manner. The two visna virus peptides also inhibited the enzymatic activity of protein kinase C, thus providing a possible molecular mechanism by which they inhibit immune function.

Amino Acid Sequence↗
PubMed1990

A double-blind, controlled trial in primary care patients with generalized anxiety: a comparison between buspirone and oxazepam.

Two hundred thirty patients with generalized anxiety and Hamilton Rating Scale for Anxiety (HAM-A) scores greater than or equal to 18 were subdivided at random, according to a double-blind design, into one group treated with 5-10 mg of oral buspirone t.i.d. or one group treated with 10-20 mg of oral oxazepam t.i.d. for 6 weeks. No anxiolytic treatment was allowed 3 months prior to trial entry. Analysis of demographic variables revealed no significant imbalance between the two treatment groups. Twenty patients were excluded from efficacy analysis because of treatment withdrawal before the first efficacy evaluation on Day 7. Another 4 patients were excluded because they were taking concomitant psychotropic medication. The remaining 206 patients displayed a decrease in HAM-A scores (mean +/- SD) from 23.9 +/- 4.1 to 10.6 +/- 7.7 in the buspirone group and from 23.9 +/- 4.2 to 11.5 +/- 8.0 in the oxazepam group. The two treatment groups were also found to be virtually identical in an "intent to treat" analysis of all 230 patients as well as in other ratings (Hamilton Rating Scale for Depression, Raskin Depression Scale, Covi Anxiety Scale, Physicians Questionnaire, global ratings, and Hopkins Symptom Checklist [HSCL]-56). However, oxazepam was never superior to buspirone in any of the efficacy analyses. Of the 230 patients, 127 spontaneously reported adverse events, including drowsiness, dizziness, headache, nausea, and nervousness. Adverse events were relatively similar in the two groups. In conclusion, buspirone and oxazepam appear to be equally effective in the treatment of generalized anxiety encountered by general practitioners. This outcome, in addition to a previously documented absence of any dependency liability, makes buspirone a clinically important anxiolytic drug.

Adolescent↗
PubMed1985

Characterization of developmentally regulated epitopes of Schistosoma mansoni egg glycoprotein antigens.

The chemical and antigenic composition of a major group of concanavalin A-binding glycoprotein antigens of Schistosoma mansoni eggs was examined by the use of monoclonal antibodies. The individual glycoproteins of this group each displayed a very wide range of apparent m.w. and had isoelectric points of less than 5 when analyzed by two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. These glycoproteins could be chemically labeled with 125Iodine by two different methods and biosynthetically labeled with 35S-methionine during in vitro synthesis by isolated eggs. By using five monoclonal antibodies, the individual egg glycoproteins were shown to share several antigenic determinants when analyzed by radioimmunoprecipitation and solid-phase binding assays. These epitopes were present in a high level, and the degree of expression appeared to be developmentally regulated. In addition, Schistosoma haematobium and Schistosoma japonicum eggs contained antigenically related glycoprotein antigens. Preliminary evidence suggests that the epitopes involve carbohydrate moieties.

Animals↗
PubMed1985

Peritoneal lavage as an aid to diagnosis of peritonitis in debilitated and elderly patients.

Twenty-seven debilitated or obtunded patients were subjected to peritoneal lavage to determine the presence or absence of peritonitis. Fourteen lavages were found to be positive, revealing peritonitis in 12 patients. Two of the 14 patients refused surgery and subsequently died. Thirteen patients had negative lavages, none of whom subsequently developed any evidence of peritonitis or required surgical intervention. Peritoneal lavage is an extremely reliable procedure, both in establishing the diagnosis of peritonitis or in ruling out its presence in debilitated or obtunded, elderly patients. The procedure can be performed quickly, without prolonged preparation, and without fear of complications. In addition, there is little cost to the procedure, especially when compared to the cost of more sophisticated time-consuming tests such as x-ray studies, gallium or CT-scanning.

Acute Disease↗
PubMed1979

Identification of a mouse gene required for binding of Rauscher MuLV envelope gp70.

Mouse chromosome segregating somatic cell hybrids were established between a mouse thymic leukemai cell line (GRSL) and Chinese hamster E36 cells. The GRSL cells specifically bound purified Rauscher leukemia virus gp70 while the E36 cells exhibited no binding. The hybrids selectively bound Ruascher gp70 depending on the presence of a mouse cellular gene for the ecotropic murine luekemia gp70 receptor. A syntenic relationship was observed between the DIP-3 chromosome marker (on chromosome 5) and the gp70 receptor in primary clones and subclones of these hybrids; this was confirmed by chromosome analysis. The involvement of H-2 in the binding of Rauscher MuLV gp70 could be ruled out, because discordancies of the receptor presence and H-2 absence as well as of the receptor absence and H-2 presence type could be observed. Our results indicate that the Rec-1 (replication ecotropic MuLV) gene of Gazdar et al. (4) may well be the receptor gene for the ecotropic murine leukemia virus.

Animals↗
PubMed1979

Interactions between cellular membrane receptors and oncovirus envelope glycoprotein: influence of enzymes and protein-modifying reagents on receptors.

Binding of purified envelope glycoprotein (gp69/71) of Rauscher murine type C oncovirus to cellular membrane receptors has been analyzed with reaction systems using intact cells or membranes of disrupted cells. The reaction was highly specific; only cells permissive to infection by Rauscher virus bound the 125I-labeled viral glycoprotein. The specificity of binding was also demonstrated with respect to virus interference; cells productively infected with murine ecotropic type C virus failed to bind the virus envelope glycoprotein, whereas permissive cells infected with murine xenotropic virus continued to bind the Rauscher ecotropic virus glycoprotein. The reaction required the presence of Ca2+ or Mn2+ and was rapid and reversible. Studies of the enzymatic digestion of membranes suggested that the receptor is a protein which requires lipid either for its activity or for the integrity in the membrane. Receptor binding was greatly reduced by modification of histidine, tyrosine, and tryptophan residues.

2-Hydroxy-5-nitrobenzyl Bromide↗
PubMed1978

Polypeptide maps of cells infected with murine type C leukemia or sarcoma oncovirus.

The polypeptide composition of murine fibroblast cells and the effect of infection by RNA sarcoma and leukemia viruses were analyzed by two-dimensional gel electrophoresis and tryptic peptide mapping. The polypeptide maps of NIH Swiss mouse embryo fibroblasts (NIH/3T3) and BALB/c mouse embryo fibroblasts (BALB/3T3) were very similar except for two major polypeptides of about 65,000 and 75,000 daltons which were not detected in BALB/3T3 cells. NIH/3T3 cells infected with either Rauscher or Gross oncoviruses and outbred Swiss mouse embryo fibroblasts (3T3 FL) showed two major polypeptrides of about 73,000 and 80,000 daltons not found in uninfected NIH/3T3 cells. The 3T3 FL cells, although uninfected, were also found to contain a high concentration of envelope glycoprotein of an endogenous oncovirus. 3T3 FL cells transformed by Moloney sarcoma virus showed changes in many polypeptides, including several major components: the disappearance or modification of a component of 60,000 daltons, an increased concentration and shift in pl of a glycoprotein of 48,000 daltons, and the apparent loss of several smaller polypeptides. None of the major changes of the transformed cells were associated with cell surface proteins labeled by lactoperoxidase-catalyzed iodination.

AKR murine leukemia virus↗
PubMed1978

Further evidence for deletion of envelope glycoprotein (gp69/71) sequences in formation of Moloney-murine sarcoma virus.

Moloney-murine sarcoma virus (S+L- strain of M-MSV) has been nonproductively cloned in murine and non-murine host cells (S+L- cells) and the expression of Moloney leukaemia virus (M-MuLV) 30000 mol. wt. core protein (p30) and envelope glycoprotein (gp69/71) were studied by radioimmunoassay. Antigenic determinants of the M-MuLV p30 were associated with the sarcoma virus genome in these non-productively transformed cell clones studied, while the determinants of M-MuLV gp69/71 were not. The absence of envelope-associated glycoprotein expression in sarcoma virus transformed cells was confirmation of biological studies demonstrating that rescued sarcoma virions acquire envelope-associated properties of host range, neutralization and interference from rescuing helper virus, and further evidence that the M-MuLV gp69/71 sequences have been deleted during the formation of the M-MSV. During the course of these studies, it was also found that S+L- dog cells were releasing into culture supernatant large amounts of the p30 antigenic determinant, apparently as a soluble antigen.

Cell Line↗
PubMed1977

Polypeptides of cells transformed by RNA or DNA tumor viruses.

Proteins solubilized from normal BALB/3T3 cells and BALB/3T3 transformed by simian virus 40 or Kirsten sarcoma virus have been analyzed by two-dimensional gel electrophoresis and tryptic peptide mapping. A large fraction of the polypeptides of the virus-transformed cells, about 30%, were different from normal cells. In contrast to the marked differences between normal and transformed cells, the polypeptides of the DNA and RNA virus-transformed cells were almost identical. These findings were observed with polypeptides stained by Coomassie Blue, or labeled with [14C]glucosamine or [35S]methionine. Pulse-chase analysis showed that most of the polypeptides were stable during 20 hr of incubation. The identity of several polypeptides was confirmed by tryptic peptide mapping.

Cell Line↗
PubMed1977

Synthesis and cleavage processing of oncornavirus proteins during interferon inhibition of virus particle release.

The effect of interferon on the rate of synthesis and the cleavage processing of viral proteins in mouse cells, chronically infected with Rauscher murine leukemia virus, has been studied by immunoprecipitation of newly synthesized viral proteins from virus-infected cells pulse-labeled with [35S]methionine. Immuno-precipitated, labeled polypeptides were resolved by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and then examined by autoradiography. Cleavage processing was studied in the same manner with cells that had been pulse-labeled and then incubated with non-radioactive media for a sufficient time to allow normal cleavage processing to occur. At a concentration that strongly inhibited the release of virus particles, interferon had no effect on the synthesis of proteins carrying antigenic determinants of the major core protein p30 or of the envelope glycoprotein gp69/71. Nor did it affect the post-translational cleavage processing of the precursors to these proteins. Similarly, interferon did not affect labeling or chasing of precursor protein carrying the p15 determinants; labeling of p15 itself could not be studied because it does not contain methionine.

Animals↗
PubMed1977

Biochemical and immunological characterization of the major envelope glycoprotein gp69/71 and degradation fragments from Rauscher leukemia virus.

Analysis of the proteins of Rauscher murine oncornavirus by immunoprecipitation showed that antiserum to the purified envelope glycoprotein of approximately 69,000 and 71,000 daltons (gp69/71) reacted as well with a number of other components of several murine oncornaviruses of approximately 45,000, 32,000, and 15,000 daltons. Polypeptides of similar size were also produced by limited proteolysis of purified gp69/71; these degradation fragments were shown to contain carbohydrate by the incorporation of (3)H from sodium boro[(3)H]hydride after neuraminidase and galactose oxidase treatment. Each of these glycoproteins was isolated by preparative polyacrylamide gel electrophoresis and was analyzed by tryptic peptide mapping. The major virion components of 69,000 and 71,000 daltons were nearly identical, as were the primary degradation fragments. Analysis of the immunological properties of the glycoproteins showed that the 71,000-, 69,000-, and 32,000-dalton glycoproteins behaved similarly with respect to type and group-specific antigenic determinants. In contrast, the 45,000-dalton glycoprotein lacked detectable interspecies and some of the group-specific reactivity. Components of about 45,000 and 32,000 daltons isolated directly from virions were also identified as constituents of the major envelope glycoprotein by immune precipitation and tryptic peptide mapping. These results indicate that all of the examined virion glycoproteins of approximately 71,000, 69,000, 45,000, and 32,000 daltons are derived from the same viral gene and that these lower-molecular-weight glycoproteins can readily be produced from the major envelope glycoprotein.

Carbohydrates↗