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M Thomas

Publications and source records attributed to M Thomas.

At least 433 records · Page 24Linked to original sources
PubMed1995

Characterization of rat spleen prostaglandin H D-isomerase as a sigma-class GSH transferase.

The prostaglandin H D-isomerase of rat immune accessory cells has been purified from spleen by a simple procedure, and its high specificity and activity [Urade, Fujimoto, Ujihara and Hayaishi (1987) J. Biol. Chem. 262, 3820-3825] have been confirmed in an assay coupled to prostaglandin H synthase. The enzyme also decreases the formation of 12[S]-hydroxy-5,8,10-heptadecatrienoic acid formed by the synthase in the presence of GSH and increases the overall rate of arachidonate oxidation. A partial amino acid sequence shows a strong relationship to GSH transferases of parasitic helminths and molluscs, indicating that it is the first example of a vertebrate sigma-class GSH transferase, and suggesting that certain helminth GSH transferases may be involved in prostaglandin synthesis.

Amino Acid Sequence↗
PubMed1995

Meningococcal disease epidemiology and control in New Zealand.

Epidemiology, surveillance and research New Zealand has a high quality surveillance system for meningococcal disease that successfully integrates notification and laboratory data. Since 1991, New Zealand has had elevated incidence rates of meningococcal disease rising to 6.2 per 100,000 population in 1994. This represents a rate that is four times that recorded in 1989/90. Serogroup B infection predominates and international experience suggests that these elevated rates may continue for 5 to 15 years. Rates of meningococcal disease in Maori and Pacific Islands populations were three times higher than in Europeans at 10.0 and 12.3 per 100,000 respectively in 1994. The rates were particularly high for infants with the rate in Maori infants under 1 year reaching 120 per 100,000. The case fatality rate at 5.3% for 1994 would appear to be relatively low by international standards. Case control studies could be used to investigate potentially modifiable primary risk factors for disease. Intensive case review studies to investigate the role of such factors as preadmission antibiotics in reducing severe outcomes may be of benefit. The Ministry of Health or research funding organisations should consider the potential value of such studies in more detail.

Adolescent↗
PubMed1995

Chromosomal location of murine protein tyrosine phosphatase (Ptprj and Ptpre) genes.

It is now widely accepted that protein tyrosine phosphatases (PTPases) play important or even critical roles in cell growth, differentiation, and development. Our recent experiments suggested that specific PTPases, PTP beta 2 and PTP epsilon, are involved in the early molecular events for in vitro differentiation of mouse erythroleukemia (MEL) as well as embryonic carcinoma (F9) cells. Using mouse cDNA for PTP beta 2 and PTP epsilon, which we have cloned recently, we attempted to locate the genes to mouse chromosomes. Interspecific backcross analysis indicated that the gene for PTP beta 2, Ptprj, is located in the middle region of chromosome 2, and the gene for PTP epsilon, Ptpre, was mapped in the vicinity of the imprinted regions in the distal part of chromosome 7. Possible biological roles of these PTPases are discussed.

Alleles↗
PubMed1995

Functional dissection of the brain-specific rat aldolase C gene promoter in transgenic mice. Essential role of two GC-rich boxes and an HNF3 binding site.

The aldolase C gene product is a glycolytic isoenzyme specifically detected in brain. We have previously defined a short 115-base pair promoter fragment able to confer on a reporter chloramphenicol acetyltransferase (CAT) gene a specific expression in brain of transgenic mice. In this promoter fragment, two GC-rich regions (A/A' and B boxes) were detected by in vitro DNase1 footprinting experiments with brain, fibroblast, or liver nuclear extracts. Both A/A' and B boxes, sharing structural homology, are able to interact with Sp1, Krox20/Krox24 factors and with other proteins (Thomas, M., Makeh, I., Briand, P., Kahn, A., and Skala, H. (1993) Eur. J. Biochem. 218, 143-151). In this paper, we describe a new ubiquitous factor termed Ub able to bind the A/A' box. We also delimit a third element (box C) binding a hepatocyte-enriched protein displaced by a hepatocyte nuclear factor 3-specific oligonucleotide. The functional involvement of each binding site in brain-specific transcription of the aldolase C gene has been tested in transgenic mice carrying different mutant promoters cloned in front of the CAT gene. A promoter containing only box C was totally inactive, suggesting an essential role of the region containing A/A' and B boxes. However, mutations or deletions of either the A/A' or the B box have no significant effect on the CAT gene expression. We therefore hypothesize that the A/A' and B sites may be functionally redundant. Indeed, constructs harboring only one of these two boxes (A/A' or B) linked to the C box displayed a brain-specific CAT activity similar to that obtained with the wild-type promoter. Furthermore, a transgene with disruption of the C box, keeping intact the A/A' and B boxes, was totally inactive, suggesting a crucial role of the hepatocyte nuclear factor 3 binding site in activation of the aldolase C gene.

Animals↗
PubMed1995

Human immunodeficiency virus infection in women in Auckland: an evolving epidemic.

AIMS: To study the epidemiology, presenting features and outcome of HIV infection among women in Auckland. METHODS: Retrospective review of the medical records of all HIV infected women cared for by the adult infectious disease unit or the sexual health clinic at Auckland Hospital up to the end of December, 1993. RESULTS: Thirty women with HIV infection were cared for between September 1986 and December 1993. Heterosexual intercourse, often with a man from a country with endemic heterosexual HIV transmission, was the most common means of acquiring HIV infection. Late diagnosis of infection probably contributed to the brief median survival seen in the nine women who developed AIDS. CONCLUSIONS: Increased education is necessary to inform women about the risks of acquiring HIV infection. This education should encourage safer sexual behaviour and the use of needle exchange programmes to minimise the growth of this epidemic.

Adolescent↗
PubMed1995

Metastasis of C1300 and TBJ murine neuroblastomas correlates with expression of matrix metalloproteinases.

Because metalloproteinases, specifically type IV collagenases, may mediate metastasis, 72- and 92-kDa collagenase activities were evaluated in two murine neuroblastoma cell lines: non-metastatic C1300 and metastatic TBJ. Zymogram analysis demonstrated that 72- and 92-kDa collagenases were associated only with metastatic TBJ. Three human neuroblastoma cell lines were then evaluated by zymogram and Western blot analyses: 72-kDa collagenase was found in metastatic SK-N-SH and IMR-32, but not in SK-N-MC, which may be a peripheral neuroectodermal tumor and not a neuroblastoma. Therefore, 72- and 92-kDa collagenases may be markers of metastasis in neuroblastoma and may aid in differentiation from other small blue cell tumors.

Animals↗
PubMed1995

Prognostic relevance of aberrations in the erbB oncogenes from breast, ovarian, oral and lung cancers: double-differential polymerase chain reaction (ddPCR) for clinical diagnosis.

We have determined the average gene copy numbers (AGCN) of the erbB-1 gene, encoding the epidermal growth factor receptor (EGF-R), the erbB-2 and the erbB-3 genes in breast, ovarian, oral, and lung cancer tissue by using double-differential PCR (ddPCR). The ddPCR method comprises the co-amplification of the single-copy gene HBB, the erbB-1, erbB-2 and erbB-3 oncogenes and the second single-copy reference gene SOD2 under equal reaction conditions. In a retrospective study the AGCN of the erbB genes and the time up to the appearance of metastases were subjected to life-table analysis in 128 women with primary breast cancer. Patients whose breast cancer tissue showed an AGCN for erbB-1 of less than 0.4 and greater then 1.6, as expected from the literature, for erbB-2 of greater than 2.0 and for erbB-3 of less than 1.75 had decreased disease-free survival (DFS). The quotient of erbB-1 and erbB-2 AGCN was the most significant in multivariate Cox analysis followed by nodal status and progesterone receptor status. In extensive studies a similar association between erbB AGCN and metastasis was seen in ovarian cancer and oral cancer, though erbB oncogene aberrations in those entities were not as frequent as in breast cancer. The AGCN of erbB oncogenes may not be of prognostic value in untreated lung cancer patients.

Base Sequence↗
PubMed1995

Abortion.

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Abortion, Legal↗
PubMed1995

HPV-18 E6 mediated inhibition of p53 DNA binding activity is independent of E6 induced degradation.

A key activity of the p53 protein during suppression of cell growth is its ability to stimulate transcription from promoters of cellular genes which contain a p53 responsive element. The E6 proteins from the oncogenic associated Human Papillomaviruses (HPVs) have been shown to inhibit specifically the p53 transcriptional activation and this has been proposed as a mechanism whereby the virus prevents the suppression of cell cycle progression and the induction of apoptosis. However, the mechanism by which E6 exercises this function is unknown, as is the ability of E6 to associate with different oligomeric forms of p53. In this study we demonstrate that E6 induces changes within the p53 protein which result both in inhibition of DNA binding and in dissociation of p53 protein previously bound to the DNA. These activities correlate exactly with the ability of E6 to inhibit p53 transcriptional activation and are independent of the ability of E6 to direct the degradation of the p53 protein. Further, we show that E6 labels wild type tetrameric and dimeric forms of p53 proteins for ubiquitin mediated degradation more readily than monomeric forms of the protein. However, in vivo analyses indicate that E6 is capable of inhibiting the transcriptional activation induced by the tetrameric, dimeric and monomeric forms of p53.

Base Sequence↗
PubMed1995

Atypical Gly-X-Y sequences surround interruptions in the repeating tripeptide pattern of basement membrane collagen.

The triple-helical domains of type IV collagen chains have more than 20 sites at which the repeating (Gly-X-Y)n pattern is interrupted. Analysis of alpha 1 (IV) and alpha 2 (IV) chains indicates the residues in the three Gly-X-Y triplets preceding or following interruptions differ statistically from the rest of the chain. Unusually high frequencies of charged residues are seen at a number of X and Y sites, with the charge density being particularly high C-terminal to the interruption site. Analyses were carried out on individual categories of interruptions, classified as insertions or deletions in the Y position. All of the residues in the X and Y positions of the triplets flanking insertion sites are atypical, with a high concentration of charged residues. Triplets flanking sites where there has been a deletion in the Y position show unusually high frequencies of charged residues at some sites, hydrophobic residues at other sites, and an invariant imino acid N-terminal to the interruption. The presence of atypical sequences surrounding interruptions could be important at a molecular level, related to triple-helix stability, or at a supramolecular level, related to the association of molecules to form networks in basement membranes.

Animals↗
PubMed1995

Analogue computation of transient changes of intracellular free Ca2+ concentration with the low affinity Ca2+ indicator furaptra during whole-cell patch-clamp recording.

The measurement of cytosolic free Ca2+ ion concentration ([Ca2+]) with low affinity Ca2+ indicators has advantages for kinetic studies of cytosolic [Ca2+] transients when compared with more commonly used high affinity Ca2+ indicators. Their dynamic range and linearity are better suited to measurement of high localised transient concentration changes that exist near sites of influx or release, and the additional buffering introduced by the indicator is minimised. The fluorescent indicator furaptra (magfura-2) has low affinity for Ca2+ (approx. 50 microM) and can be used conveniently with single wavelength excitation at 420 nm with the procedure described by Konishi et al. [6]. The application of this protocol in whole-cell patch-clamp recording permits calibrated measurements of [Ca2+] during an experiment with minimal distortion of the time course and amplitude of [Ca2+] transients. A simple and inexpensive analogue circuit is described for direct computation of [Ca2+] from furaptra fluorescence with single wavelength excitation and emission during whole-cell recording. Data are shown which compare furaptra and fluo-3 estimates of the time course and amplitude of [Ca2+] changes in vascular endothelia, Purkinje neurones and hepatocytes.

Aniline Compounds↗
PubMed1995

Genotyping of a patient homozygous for a rare apolipoprotein E1 [Gly127-->Asp; Arg158-->Cys] (Weisgraber allele).

We examined the apolipoprotein E polymorphism of an obese patient presenting non-insulin-dependent diabetes, hypertension and moderate lipid disturbances. The apolipoprotein E genotyping carried out from leukocyte DNA using PCR amplification and restriction enzyme digestion demonstrated homozygosity for the rare apoE1[Gly127-->Asp; Arg158--> Cys] (Weisgraber allele). The nucleotide change results in a glycine to aspartic acid substitution at amino acid 127 in the apolipoprotein E2.

Alleles↗
PubMed1995

Beyond specificity: effects of serotonin and serotonergic treatments on psychobiological dysfunction.

Serotonin is a ubiquitous neurotransmitter with widespread projections that provide for the involvement of serotonin in the regulation of many biological and psychological functions. A variety of serotonin receptor subtypes exist that mediate overlapping psychobiological functions and that are targets for a new generation of medications. Although these new generation medications appear to possess great biochemical specificity, their actions extend to many psychiatric disorders, reflecting the many interactions of serotonergic subsystems.

Brain↗
PubMed1995

The experience of labour: a perspective from those receiving care in a midwife-led unit.

AIM: to elucidate the experience of labour for those receiving any aspect of care in a midwife-led unit. PARTICIPANTS: a total of 32 women and six partners who were interviewed during the postnatal period, either prior to discharge from the unit or between three and five months following delivery. METHOD: in-depth focused interviews were taped, transcribed, and analysed using a grounded theory approach to identify common categories of experience. FINDINGS: the core category to emerge was the balance of perceived control and perceived support. Sub-categories included feeling informed, having options and choices, a supportive environment and someone to trust and give confidence. Continuity of care was found not to be an option for those whose care was transferred during pregnancy or labour. CONCLUSIONS: staffing levels which provide immediate access to the support of the midwife throughout labour enhance personal control. Those with the greatest need for support and continuity of care and carer are among those least likely to receive it.

Female↗