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Biomedical subjects

M Suh

Publications and source records attributed to M Suh.

At least 19 recordsLinked to original sources
PubMed1992

Impact of dietary fatty acid balance on membrane structure and function of neuronal tissues.

Neural tissue has generally been viewed as resistant to structural changes induced by exogenous factors. Research has shown that the brain responds to changes in diet by altering neurotransmitter synthesis, and by shifting neuroendocrine controls over a variety of physiological events. Animal model research also indicates that fatty acid constituents and synthesis of brain structural lipid in membranes undergoing turnover can be altered by changing the composition of dietary fat. In growing animals, the balance between dietary omega 6 and omega 3 fatty acids influences brain phospholipid fatty acid composition, phosphatidylethanolamine methyltransferase activity, and rate of phosphatidylcholine biosynthesis via the CDP-choline pathway. It is concluded that biosynthetic control mechanisms regulating synthesis of brain structural lipid, in particular phosphatidylcholine, respond to exogenous factors and represent a normal physiological response by the brain. This response may provide a mechanism for therapeutic treatment of disorders involving degeneration of brain structural lipid.

Animals↗
PubMed1992

Failure of thumbtacks used in control of presacral hemorrhage.

We report a case of failure of thumbtacks used in achieving last-resort hemostasis in a gunshot injury to the presacral venous plexus/sacrum. Four of five thumbtacks used detached. The exact mechanism of failure is not known. To our knowledge, there are no reports of failure of these hemostatic devices in the literature. This finding suggests to us that thumbtack hemostasis is not without complication. It is not known whether injury to internal viscera and organs occurred secondary to the loose thumbtacks. We suggest that surgeons as well as pathologists use caution when exploring pelvic or abdominal cavities following pelvic vascular trauma due to the considerable danger posed by these sharp objects.

Abdominal Injuries↗
PubMed1991

Human gliomas and epileptic foci express high levels of a mRNA related to rat testicular sulfated glycoprotein 2, a purported marker of cell death.

Clone pTB16 has been isolated by differential screening of a human glioma cDNA library. Northern blot analysis has shown that pTB16 expression is several times (greater than 11-fold) higher in gliomas than in a primitive neuroectodermal tumor. This observation was supported by in situ hybridization and extended to nine other gliomas. Expression was virtually absent in adenocarcinoma cells metastasized to brain. Malignant gliomas showed stronger hybridization than benign gliomas, while blood capillaries did not show hybridization. pTB16 mRNA was also shown to be expressed in established glioma cell lines and at high levels in epileptic foci, indicating that expression of the gene may be limited to certain cell types and that its upregulation is not merely a consequence of cellular proliferation. Nucleotide sequence analysis identified pTB16 as the human counterpart for rat testicular sulfated glycoprotein 2 (SGP-2), whose function in the reproductive system remains unknown. Although SGP-2 transcripts, and hence pTB16, were recently shown to be increased in neurodegenerative diseases such as scrapie in hamsters and Alzheimer disease in humans, our observations with brain tumors and epilepsy are suggestive of a role for pTB16 in neuropathologies in general and support the hypothesis of its involvement in tissue remodeling and cell death.

Blotting, Northern↗
PubMed1991

Expression in bacteria of a polypeptide encoded by a transforming fragment of herpes simplex virus type 2.

We have constructed a plasmid (pMD2) containing the 38,000 MW polypeptide (38K polypeptide) gene from the transforming Bg1II-N fragment of HSV-2 fused to the amino-terminal portion of the beta-galactosidase gene in plasmid pUC8. Nucleotide sequence determination around the fusion-junction confirmed that the viral gene sequences starting at its second codon is in the correct reading frame in relation to the translation initiation codon of beta-galactosidase. The lac control sequences direct the synthesis of a 39K protein. This protein was shown to be structurally related to the 38K protein from HSV-2-infected cells by partial proteolytic cleavage analysis. Furthermore, antiserum directed against HSV-2-infected cells, as well as a monoclonal antibody against the 38K viral polypeptide and antibodies raised against a synthetic peptide corresponding to the nine C-terminal amino acid residues of the 38K viral protein, detected the fusion protein in bacteria containing the recombinant plasmid pMD2 but not in Escherichia coli containing a related plasmid or no plasmid.

Animals↗
PubMed1990

Failure to detect viral genomic sequences of three viruses (herpes simplex, simian virus 40 and adenovirus) in human and rat brain tumors.

Little is known about oncogenesis in brain tumors. Viruses are thought to be involved in some neurological diseases, the presence of subfractions of viral DNA has been reported in various circumstances and the oncogenicity of some viruses has been demonstrated in animal experiments. The discovery of homologies between retroviral oncogenes and normal cellular genes (proto-oncogenes) has stimulated once again the search for viral responsibility in oncogenesis. Having a large bank of tumor material available, we systematically examined 39 brain tumors using Southern blot hybridization with DNAs of three viruses, known to be involved in neurological diseases: herpes simplex virus (HSV), simian virus 40 (SV40) and adenovirus type 2 (Ad2). We detected no homology between the DNAs of the examined material and the viral DNA probes. We compare these negative results with those of other published studies and discuss the experimental conditions, with special reference to the possibility of non-specific hybridization, which could account for the positive results reported. The present negative results could be interpreted either as absence of involvement of the three investigated viruses in brain tumor oncogenesis, or an indirect involvement through a hit-and-run mechanism or a highly dispersed state of the viral sequences among the host genome, which would prevent hybridization with the probe, as it has been supposed to be the case during the latency phase of herpes virus.

Adenoviridae↗
PubMed1990

Serum amyloid A protein-related mRNA expression in herpes simplex virus type 2-transformed hamster cells.

A nearly full-length cDNA very similar to murine serum amyloid A protein was cloned from herpes simplex virus type 2-transformed hamster cells. The expression of mRNA was constitutive in these cells and could be superinduced by conditioned medium. Higher rates of nuclear runoff transcription in transformed and induced cells indicated some regulation at the transcriptional level.

Amino Acid Sequence↗
PubMed1988

Identification of a proliferation-related transcript with an elevated expression in the mid-gestation mouse embryo.

Polyadenylated RNA enriched in transformation specific sequences from hamster embryo fibroblast cells transformed by HSV-2 was used to construct a cDNA library. A cDNA clone (pKG4) contained a sequence which was upregulated in HSV-2 transformed cells and also in fibroblastic cell lines transformed by SV40 and 3-methylcholanthrene. The expression of the KG4 sequences in HSV-2-transformed cells was found to be modulated by the growth state of the cells. In confluent cells its level was reduced 5-times compared to the homologous RNAs from exponentially growing cells. Expression of the KG4 sequence was also examined in mouse embryos from day 8 onwards and in adult tissues. During development, KG4 is expressed at all times examined. However, there is a dramatic increase in expression on day 11. In adult tissues, a low and variable level of expression was observed. These findings suggest that the KG4 sequence is related to cellular proliferation.

Animals↗
PubMed1988

Specific induction of cellular gene transcription in herpes simplex virus type 2-transformed cells.

In spite of much work, the mechanism of oncogenic transformation by herpes simplex virus (HSV) is as yet unknown. It has been proposed that HSV type 2 (HSV-2) can transform cells by a 'hit and run' mechanism. In the past we have demonstrated that several polypeptides can be immunoprecipitated from HSV-2-transformed cells, but not from control cells or adenovirus-transformed cells, by rabbit hyperimmune sera to HSV-2. It is possible that the expression of these proteins might be the result of activation of cellular genes during transformation. We have now isolated cDNAs representing transcripts of genes that are expressed at higher levels in HSV-2-transformed hamster embryo fibroblasts than in the parental cells. Cytoplasmic transcripts and genomic sequences homologous to three clones (pAA8, pHD1 and pLC7) were analysed. Northern blot analyses showed that 0.75 kb transcripts which hybridize to the three cDNAs were present in HSV-2-transformed cells and were completely absent or present at low levels in control hamster fibroblasts. These transcripts were not present in mouse cells transformed by other DNA viruses or by a chemical carcinogen. The expression of these transcripts seemed to be confined to certain HSV-2-transformed cell lines. Southern blot analysis suggested that the 0.75 kb transcripts corresponding to these cDNAs may have arisen from a single gene. Nuclear run-off experiments indicated that activation occurred at the level of transcription. The activation of the gene or genes corresponding to these cDNAs may be an integral part of the mechanism of transformation by HSV-2.

Animals↗
PubMed1987

Activities of both ribonucleotide reductase subunits, M1 and M2, decrease upon serum starvation of baby hamster kidney 21/C13 cells.

Ribonucleotide reductase from mammalian cells is composed of two nonidentical subunits M1 and M2 which are both required to form the catalytic site. The level of ribonucleotide reductase activity is cell cycle controlled and several reports suggest that this control is achieved mainly by the regulation of M2 subunit synthesis. In the present study, we have found that the activities of both subunits decreased markedly upon serum starvation in the Syrian baby hamster kidney 21/C13 cell line. These decreases did not seem to be correlated with the appearance of an inhibitory factor in serum-starved cells. Quantification of the amount of the M1 subunit protein (89,000 molecular weight) by [32P]dTTP photoaffinity labelling revealed that the decrease in M1 activity was not due to variation in M1 protein level. Therefore, a posttranslational mechanism probably exists which inactivates M1 subunit when cells stay in the quiescent (G0) state and this mechanism could play an important role in the control of ribonucleotide reductase activity.

Animals↗
PubMed1986

Lymph node primary immunization of mice for the production of polyclonal and monoclonal antibodies.

Primary immunization of mice by lymph node injection of bovine serum albumin (BSA) in doses as low as 1 ng followed by a secondary immunization with 1 microgram each for intraperiteonal and intravenous injections was sufficient to elicit the production of circulating antibodies. The lowest efficient dose tested was the injection of 100 ng of BSA in the lymph nodes and booster injections of 1 ng each. This method was extended to the production of monoclonal antibodies using less than 20 micrograms of a 35 kDa polypeptide purified from hamster cells transformed by Herpes simplex type 2 viruses.

Animals↗
PubMed1986

Herpes-related polypeptides from a human cervical carcinoma cell line.

Using antiserum against herpes simplex virus type 2 (HSV-2) infected cells, eight polypeptides with similar molecular weights could be immunoprecipitated from the nearly diploid, human cervical carcinoma cell line C4II and from HSV-2 transformed hamster and mouse cells. Only two of these polypeptides corresponded to those from HSV-2 infected cells, including the putative HSV-2 transformation-related 35K protein. Partial proteolytic cleavage products of the immunoprecipitated 35K polypeptides from C4II and HSV transformed hamster and infected cells were indistinguishable; however, viral DNA and mRNA corresponding to the 35K polypeptide could not be detected in C4II or in transformed hamster or mouse cells by dot blot hybridization. A similar mechanism of transformation for the human cervical carcinoma cell line and HSV-2 transformed cells is proposed.

Animals↗
PubMed1979

A socio-psychiatric profile of emergency service patients.

A study of patients using the psychiatric emergency services of the Royal Ottawa Hospital was undertaken to determine their demographic and clinical characteristics, correlations between the two and comparisons with other studies. Special clinical forms of every fifth patient seen were analyzed and the data presented. These data are useful in the planning of and establishing and operating a psychiatric emergency service with an attached short-term inpatient unit, as well as assessing the feasibility and value of crisis intervention and brief psychotherapy in treating patients quickly.

Adolescent↗
PubMed1979

Analysis of chromosomes, nucleic acids, and polypeptides in hamster cells transformed by herpes simplex virus type 2.

Syrian hamster embryo fibroblasts were oncogenically transformed by UV-inactivated Herpes simplex type 2. Eighteen clones were isolated shortly after transformation occurred. Two clones and their tumor derivatives were studied using several techniques. The karyotype analysis revealed different chromosome patterns in the two clones and a tendency toward hypodiploidy in the tumor derivatives. All of these cell lines were shown by molecular hybridization to contain 40% of the HSV-genome in several copies. The viral DNA sequence complexity was retained in the tumor derivatives, but a decrease in the copy number was observed. Viral RNA's were detected by in situ hybridization in all the lines that were tested. Viral antigens could be observed in these transformed cells by immunofluorescence. Finally, polypeptide analysis showed three differences between normal and transformed cells.

Animals↗