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Biomedical subjects

M Allen

Publications and source records attributed to M Allen.

At least 91 records · Page 5Linked to original sources
PubMed1998

Selecting keywords: helping others find your article.

Keywords or indexing words help the intended audience of your article both directly and indirectly. Directly, they help the reader identify the topics covered. Indirectly, they help indexers identify the subject headings used in journal indexes and databases. This article reviews the indexing process, provides a step-by-step way of identifying keywords for your article, and identifies some common pitfalls to avoid.

Abstracting and Indexing↗
PubMed1998

Mitochondrial DNA sequencing of shed hairs and saliva on robbery caps: sensitivity and matching probabilities.

Sequencing of mitochondrial DNA (mtDNA) has been used for human identification based on teeth and skeletal remains. Here, we describe an amplification system for the mtDNA control region (D-loop) suited for the analysis of shed hair, which constitutes the most common biological evidence material in forensic investigations. The success rate was over 90% when applied to evidence materials such as shed hair, saliva stains and saliva on stamps. The analysis of evidence materials collected from three similar robberies revealed the presence of mtDNA sequences identical to those of the suspects in the three crimes. The use of mtDNA control region sequences for individual identification was evaluated. The probability of identity by chance for the mtDNA types of the suspects in the robberies was found to vary between Pr = 0.017 - < 0.0017, depending on the reference population used, emphasizing the need for large population databases to obtain the appropriate estimate.

Base Sequence↗
PubMed1997

The effects of Down syndrome and other chromosomal abnormalities on survival and management in oesophageal atresia.

Recognisable chromosomal abnormalities occur in over 5% of patients with oesophageal atresia (OA). In a review of 670 patients with OA chromosomal abnormalities were identified in 35 (5.2%), of whom 16 had trisomy 18 and 12 had trisomy 21. In patients with trisomy 18, the diagnosis should be suspected on clinical grounds and confirmed on analysis of chromosomes; no active treatment of the OA is justified because of the extremely poor prognosis. In Down syndrome (DS) 50% will have pure OA with no tracheo-oesophageal fistula. In addition, many of these infants will have associated anomalies typical of those normally seen in DS, eg., Hirschsprung's disease, duodenal atresia, and congenital heart disease. Despite treatment, OA with DS has a high mortality.

Abnormalities, Multiple↗
PubMed1997

Phenotypic characterization and analysis of allogeneic T cell responses in ZAP-70 dominant negative transgenic mice.

Antigen stimulation of T cells results in a series of biochemical events including the interaction of both SH2 domains of ZAP-70 with phosphorylated ITAMS on the T cell receptor. In order to study the physiological relevance of decreasing native ZAP-70-SH2 interaction in vivo, we generated transgenic mice expressing a T cell-specific, dominant negative form of ZAP-70 consisting of only the tandem SH2 domains (ZAP-NC). Phenotypically, these animals had a comparable distribution of lymphocyte subsets in the thymus and spleen compared with the wild-type (WT) controls. However, examination of peripheral blood revealed a slow but progressive decrease in the number of lymphocytes, particularly CD4+ cells, with age (17% reduction by 3 months, 58% reduction by 6 months). Allogeneic responses were then evaluated in vitro as well as in vivo using a subcutaneous sponge matrix implant. Although spleen cells cultured for 4 days in vitro with alloantigen developed normal functional responses, allogeneic responses generated in vivo within a subcutaneous sponge matrix were impaired. This was characterized by a depression in cytotoxic T lymphocyte (CTL) activity, a 82% reduction in the frequency of helper T cells, and a 78% reduction in the capacity of sponge-infiltrating lymphocytes to produce IL-2 in response to secondary antigen stimulation. These results indicate that although overt lymphocyte development and in vitro function were unremarkable, expression of a truncated ZAP-70 affected the in vivo survival of peripheral lymphocytes and altered the in vivo generation of functional activity to alloantigen.

Animals↗
PubMed1997

Merger motorway. Giving staff the tools to reengineer.

Mergers and health care agencies' response to mergers dominate current conversations in this evolving managed care environment. Hospitals are rapidly learning to adjust to declining occupancy rates and deceased utilization of resources. A business model to guide mergers was adapted to assist staff with the people, structural, cultural and political issues of organizational change. Creating successful new work environments, moving from a "We-they" mentality to unity and decreasing use of resources are outcomes described in this article.

Adaptation, Psychological↗
PubMed1997

Overexpression of the angiogenic factor platelet-derived endothelial cell growth factor/thymidine phosphorylase in psoriatic epidermis.

Considerable evidence indicates that the microvascular changes observed in psoriasis are a result of angiogenesis. Vascular proliferation is driven by the local production of molecules which have angiogenic activity. Platelet-derived endothelial cell growth factor/thymidine phosphorylase (PDECGF/TP) is a potent angiogenic factor active in in vivo angiogenesis assays and overexpressed in several tumour types. We have demonstrated by ribonuclease protection analysis a consistently high degree of PDECGF/TP mRNA production in lesional psoriatic skin, while immunohistochemical studies revealed strong PDECGF/TP immunoreactivity in lesional epidermis, with nuclear staining present in basal keratinocytes and cytoplasmic immunoreactivity in suprabasal layers. Non-lesional skin showed minimal PDECGF/TP mRNA production and weak epidermal immunostaining. These results indicate a potential role for PDECGF/TP in the pathophysiology of psoriasis, and reveal a target for antiangiogenesis therapy in the treatment of this disease.

Adult↗
PubMed1996

ATP-citrate lyase as a target for hypolipidemic intervention. Design and synthesis of 2-substituted butanedioic acids as novel, potent inhibitors of the enzyme.

ATP-citrate lyase is the primary enzyme responsible for the synthesis of cytosolic acetyl-CoA in many tissues. Inhibitors of the enzyme represent a potentially novel class of hypolipidemic agent, which are anticipated to have combined hypocholesterolemic and hypotriglyceridemic properties. A series of 2-substituted butanedioic acids have been designed and synthesized as inhibitors of the enzyme. The best compounds, 58, 68, 71, 74 have reversible Ki's in the 1-3 microM range against the isolated rat enzyme. As representative of this compound class, 58, has been shown to exert its inhibitory action through a mainly competitive mechanism with respect to citrate and a noncompetitive one with respect to CoA. None of the inhibitors were able to inhibit cholesterol and/or fatty acid synthesis in HepG2 cells. This has been attributed to the adverse physicochemical properties of the molecules leading to a lack of cell penetration. Despite this, a lead structural class of compound has been identified with the potential for modification into potent, cell-penetrant, and efficacious inhibitors of ATP-citrate lyase.

ATP Citrate (pro-S)-Lyase↗
PubMed1996

Sequence specific binding of chlamydial histone H1-like protein.

Chlamydia trachomatis is one of the few prokaryotic organisms known to contain proteins that bear homology to eukaryotic histone H1. Changes in macromolecular conformation of DNA mediated by the histone H1-like protein (Hc1) appear to regulate stage specific differentiation. We have developed a cross-linking immunoprecipitation protocol to examine in vivo protein-DNA interaction by immune precipitating chlamydial Hc1 cross linked to DNA. Our results strongly support the presence of sequence specific binding sites on the chlamydial plasmid and hc1 gene upstream of its open reading frame. The preferential binding sites were mapped to 520 bp BamHI-XhoI and 547 bp BamHI-DraI DNA fragments on the plasmid and hc1 respectively. Comparison of these two DNA sequences using Bestfit program has identified a 24 bp region with >75% identity that is unique to the chlamydial genome. Double-stranded DNA prepared by annealing complementary oligonucleotides corresponding to the conserved 24 bp region bind Hc1, in contrast to control sequences with similar A+T ratios. Further, Hc1 binds to DNA in a strand specific fashion, with preferential binding for only one strand. The site specific affinity to plasmid DNA was also demonstrated by atomic force microscopy data images. Binding was always followed by coiling, shrinking and aggregation of the affected DNA. Very low protein-DNA ratio was required if incubations were carried out in solution. However, if DNA was partially immobilized on mica substrate individual strands with dark foci were still visible even after the addition of excess Hc1.

Bacterial Proteins↗
PubMed1996

Fetal growth and cardiovascular risk factors in Jamaican schoolchildren.

OBJECTIVE: To determine relation between schoolchildren's blood pressure, glycated haemoglobin level, and cholesterol concentration and their anthropometry, socioeconomic status, and birth measurements. DESIGN: Retrospective cohort study. SETTING: 27 schools closest to University Hospital of the West Indies, Kingston, Jamaica. SUBJECTS: 2337 children aged 6-16 years who were born at university hospital were recruited, and their birth records were recovered: 1610 had suitable records, 659 had records including birth length, and 610 of these were prepubertal. MAIN OUTCOME MEASURES: Blood pressure, glycated haemoglobin level, serum cholesterol concentration, anthropometry at birth, current anthropometry, and socioeconomic status. RESULTS: Multiple regression analysis showed that children's systolic blood pressure was inversely related to their birth weight (P < 0.0001) and directly related to their current weight. Glycated haemoglobin level was higher in children with thicker triceps skinfolds (P < 0.001) and who had been shorter at birth (P = 0.003). Serum cholesterol concentration was inversely related to current height (P = 0.001) and to length at birth (P = 0.09) and was directly related to triceps skinfold thickness and higher socioeconomic status (P < 0.001). CONCLUSIONS: Blood pressure in childhood was inversely related to birth weight and directly to current weight. Glycaemic control and serum cholesterol were related to short length at birth, height deficit in childhood, and childhood obesity.

Adolescent↗