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Biomedical subjects

R Roy

Publications and source records attributed to R Roy.

At least 217 records · Page 12Linked to original sources
PubMed1995

AmpliType PM and HLA DQ alpha typing from pap smear, semen smear, and postcoital slides.

Deoxyribonucleic acid (DNA) samples extracted from stained pap smear, semen smear and postcoital slides were amplified by the polymerase chain reaction (PCR) and typed for the AmpliType PM and HLA DQ alpha alleles. HLA DQ alpha and PM types consistent with blood controls from the donors were obtained. Stained cells fixed to slides can provide a valuable source of material for determining a genetic profile of the sample donor, particularly in sexual assault cases and possibly in missing person cases involving women.

Coitus↗
PubMed1995

[Infanticide committed by the mother].

Using data gathered at the Institut Philippe Pinel in Montréal, we shall describe the sociodemographic and psychiatric profile of a sample of 17 women who have killed (n = 14) or attempted to kill (n = 3) one of their children. Our data indicate that women who have committed this type of offence generally come from a disadvantaged socioeconomic environment. Most have a psychiatric history (evaluation and/or hospitalization). Review of the offence demonstrates that most women do not use a weapon to kill their child; the preferred methods are strangulation or drowning. Most of these offences may be classified as extended suicide or altruistic acts. Several of the women present with a severe personality disorder and an additional depressive episode in the context of the offence. We hope our study will help clarify understanding of filicide and assist in the development of certain prevention axes. These results indicate that the population at large and various intervenors in our society (family physicians, psychiatrists, criminologists, social workers, pediatricians, psychologists, gynecologists) must become increasingly vigilant and avoid trivialization of signals such as verbalization of homicidal thoughts about the child or recourse to certain disorganized behaviours.

Adult↗
PubMed1994

Purification and biochemical characterization of recombinant N-methylpurine-DNA glycosylase of the mouse.

The mouse N-methylpurine-DNA glycosylase (MPG), responsible for the removal of most N-alkyladducts in DNA, was purified to homogeneity as a recombinant nonfusion protein from Escherichia coli. Only 10-15% of the protein was present in the soluble form in E. coli cells. The N-terminal amino acid sequence of the purified protein which lacks 48 residues from the amino terminus of the wild type protein was identical to that predicted from the nucleotide sequence. The glycosylase hydrolyzes 3-methyladenine (m3A), 7-methylguanine(m7G), and 3-methylguanine (m3G) from DNA, and the Km and kcat values were 130 nM and 0.8 min-1 for m3A, and 860 nM and 0.2 min-1 for m7G, respectively, when methylated calf thymus DNA was used as the substrate. A comparison of kcat/Km values for different bases indicates that the enzyme was more efficient in excising both m3A and m3G than m7G from methylated DNA. The enzyme showed moderate binding affinities (KA) for both methylated (5.8 x 10(7) M-1) and nonmethylated DNAs (4.2 x 10(7) M-1). The mouse protein has an extinction coefficient E280nm1% of 10.5 and a pI of 9.3. The enzyme activity was optimal in the presence of 100 mM NaCl, with a broad pH optimum of 8.5-9.5. The enzymatic release of both m3A and m7G was stimulated 50-75% by 0.5 mM MgCl2 and 0.02 mM spermine but inhibited by higher concentrations of these agents. Product inhibition by 40-50% of the reaction occurred in the presence of 10 mM m3A or m7G. However, 1.0 mM m3A stimulated release of m7G. The enzyme was inhibited by 60% in the presence of 0.9 mg/mL DNA which, at the same time, protected it from thermal inactivation.

Adenine↗
PubMed1994

The MO15 cell cycle kinase is associated with the TFIIH transcription-DNA repair factor.

A protein kinase activity that phosphorylates the C-terminal domain (CTD) of RNA polymerase II and is associated with the basal transcription-repair factor TFIIH (also called BTF2) resides with MO15, a cyclin-dependent protein kinase that was first found to be involved in cell cycle regulation. Using in vivo and in vitro repair assays, we show that MO15 is important for nucleotide excision repair, most likely through its association with TFIIH, thus providing an unexpected link among three important cellular mechanisms.

Amino Acid Sequence↗
PubMed1994

Posttransplant antibodies and fresh venous allograft failure in dogs.

Small diameter arterial reconstruction is usually achieved by use of the autologous long saphenous vein. As an alternative to this blood conduit, the venous allograft has been used with some success in the past, but is likely to be the target of an immune rejection reaction from the host. This study was designed to characterize humoral immune reactions possibly involved in the outcome of venous allografts. Ten mongrel dogs received a histoincompatible femoral vein allograft and an autograft as interposition grafts to both femoral arteries. They were investigated for donor-specific antibody development using donor splenocytes and cultured vascular endothelial cells (EC). Serum samples were collected at surgery, at 2 weeks, and every month until graft occlusion occurred. All autografts were patent at retrieval except one, and all allografts underwent thrombosis. In all dogs, donor-specific IgG development was observed that appeared specifically at 4 weeks and lasted until graft occlusion was detected. All reactive sera were cytotoxic to donor EC except one, and this reactivity was completely lost after serum absorption on donor splenocytes. This latter absorption resulted in the total loss of flow cytometric reactivity against donor EC in 3 dogs, whereas a low reactivity was still present in 4 dogs. Immunoblotting analysis showed a posttransplant reactivity against various protein bands on donor EC. Absorption of the reactive serum on donor splenocytes resulted in the loss of reactivity to proteins of approximately 40, 30, and 22 kDa in most experiments. Moreover, as demonstrated by immunofluorescence on cryostat sections of explanted grafts, IgG deposition was seen mainly in the media and the adventitia of the allografts but not in autografts. These results suggest that a donor-specific antibody response directed mainly against MHC antigens might play a role in the thrombosis of histoincompatible venous allografts, thus decreasing the patency rate.

Animals↗
PubMed1994

The ERCC2/DNA repair protein is associated with the class II BTF2/TFIIH transcription factor.

ERCC2 is involved in the DNA repair syndrome xeroderma pigmentosum (XP) group D and was found to copurify with the RNA polymerase II (B) transcription factor BTF2/TFIIH that possesses a bidirectional helicase activity. Antibodies directed towards the 89 kDa (ERCC3) or the p62 subunit of BTF2 are able to either immunoprecipitate ERCC2 or shift the polypeptide in a glycerol gradient. Conversely, an antibody directed towards ERCC2 also retains or shifts BTF2. ERCC2 could be resolved from the other characterized components of BTF2 upon salt treatment, while its readdition enhanced BTF2 transcription activity. ERCC2, ERCC3 and p44 are three repair proteins found in association with BTF2. Two of them, ERCC2 and ERCC3, are responsible for atypical forms of XP disorders which confer a high predisposition to skin cancer. This includes clinical features that lack an adequate rationalization on the basis of nucleotide excision repair (NER) deficiency but which may now be explained better in terms of a partial transcription deficiency.

Amino Acid Sequence↗
PubMed1994

Interaction of trichloroethylene with phosphatidylcholine and its localization in the phosphatidylcholine vesicles: a 1H-NMR study.

The interaction of trichloroethylene, an inhalation general anesthetic, with egg yolk phosphatidylcholine (EYPC) and its localization in small unilamellar vesicles (SUV) has been studied by Nuclear Magnetic Resonance. These studies demonstrate that inhalation anesthetic can interact nonspecifically with lipid molecules. Furthermore, it suggests that the action of inhalation anesthetics is directed primarily to the interfacial region of the lipid membrane.

Lipid Bilayers↗
PubMed1994

The DNA-dependent ATPase activity associated with the class II basic transcription factor BTF2/TFIIH.

BTF2/TFIIH from human, delta from rat, and factor b from yeast are multisubunit basal transcription factors that have been shown to be closely associated with a protein kinase capable of phosphorylating the carboxyl-terminal domain of the large subunit of RNA polymerase II (Lu, H., Zawel, L., Fischer, L., Egly, J. M., and Reinberg, D. (1992) Nature 358, 641-645; Serizawa, H., Conaway, R. C., and Conaway, J. W. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 7476-7480; Feaver, W. J., Gileadi, O., and Kornberg, R. D. (1991) Cell 67, 1223-1230). We report here that a DNA-dependent ATPase and the previously characterized helicase (Schaeffer, L., Roy, R., Humbert, S., Moncollin, V., Vermeulen, W., Hoeijmakers, J., Chambon, P., and Egly, J. M. (1993) Science 260, 58-63) are both associated with BTF2 and reside with the p89 polypeptide subunit. The DNA requirement, the effect of Sarkosyl and staurosporine inhibitors, as well as nucleotide competition experiments, clearly distinguished ATPase/helicase from the carboxyl-terminal domain kinase. Using recombinant wild type or mutated p89/ERCC3 polypeptides and different forms of DNA template, we show the connection between ATPase and the helicase.

Adenosine Triphosphatases↗
PubMed1994

1,N6-ethenoadenine is preferred over 3-methyladenine as substrate by a cloned human N-methylpurine-DNA glycosylase (3-methyladenine-DNA glycosylase).

A lethal DNA adduct induced by methylating agents, 3-methyladenine (m3A), is removed by both the constitutive (Tag) and inducible (AlkA) bacterial m3A-DNA glycosylases. The human 3-methyladenine-DNA glycosylase also releases m3A as well as other methylated bases. The rate of release of m3A from alkylated DNA by the purified or recombinant human m3A glycosylase is much higher than that of the other methylated bases. We now find that a partially purified recombinant human m3A-DNA glycosylase, expressed in Escherichia coli, releases at least 10-fold more 1,N6-ethenoadenine (epsilon A) than m3A from DNA. epsilon A is completely unrelated to m3A since it is a heterocyclic adduct produced by the carcinogen vinyl chloride. The rates of release of epsilon A and m3A were both dependent on protein concentration and time. The differential release of epsilon A and m3A occurs regardless of whether DNA containing each adduct is assayed separately or is assayed in a mixed substrate containing both DNAs. This result raises the question of what structural features are involved in recognition and excision by the human m3A-DNA glycosylase and what may be its primary substrate.

Adenine↗
PubMed1994

Human myoblast transplantation in immunodeficient and immunosuppressed mice: evidence of rejection.

Normal human myoblasts were cloned and transplanted in the tibialis anterior of immunodeficient nude and SCID mice and in mdx mice under different immunosuppressive treatments (cyclosporine A, CsA; antilymphocyte serum, ALS) or not immunosuppressed. This permitted us to show the interaction of the immune system in the myoblast transplantation. The graft success was assessed by verifying signs of humoral and cellular immune reactions and the presence of dystrophin produced by the fusion of the donor myoblasts. This study showed that clones of human myoblasts were able to fuse and produce dystrophin in injected muscles of immunodeficient mice and mdx mice receiving an effective immunosuppressive treatment (i.e., ALS+CsA). However, the same pool of human myoblasts injected in mdx mice inadequately immunosuppressed (i.e., CsA alone or ALS alone) triggered an immune reaction and was rejected. Cells expressing CD4 and CD8 antigens were observed in the injected muscles of mice treated with CsA alone. Therefore, evidence of humoral and cellular rejection was observed following human myoblasts transplantation.

Animals↗
PubMed1994

Very efficient myoblast allotransplantation in mice under FK506 immunosuppression.

Transgenic CD1 mice expressing beta-galactosidase were used as myoblast donors. The myoblasts were injected in normal or mdx muscles previously irradiated and injected with notexin. Twenty-eight days after myoblast transplantation, the percentage of muscle fibers beta-glactosidase-positive was low in mice not immunosuppressed but was high (80%) in those treated with FK506. In mdx mice, muscle fibers expressing beta-galactosidase were also dystrophin positive. Most of the mice not treated with FK506 produced antibodies against the donor myoblasts. These results indicate that FK506 is a very useful immunosuppressive drug for myoblast transplantation in mice. Irradiation and notexin injection used in our experiments are, however, not feasible in humans. Other manipulations capable of increasing the participation of donor myoblasts to regeneration will therefore have to be identified before new clinical trials are attempted.

Animals↗