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Biomedical subjects

G West

Publications and source records attributed to G West.

At least 37 records · Page 2Linked to original sources
PubMed1995

Adequacy of mucosal biopsies for evaluation of intestinal cytokine-specific mRNA. Comparative study of RT-PCR in biopsies and isolated cells from normal and inflamed intestine.

Endoscopic biopsies are being increasingly utilized to investigate cytokine profiles in normal and diseased intestine. To evaluate the adequacy of mucosal biopsies as a source of cytokine-specific mRNA, we measured their content of interleukin-1 beta (IL-1 beta) and interleukin-2 (IL-2) mRNA by reverse transcription-polymerase chain reaction and compared it to that of autologous lamina propria mononuclear cells in control and inflammatory bowel disease-involved specimens. High-quality total RNA was recovered more consistently from cell isolates than from biopsies. Interleukin-1 beta mRNA was reliably detected in both cell and biopsy samples, whereas IL-2 mRNA was measurable in all lamina propria cells but not always in biopsies. Compared to controls, levels of IL-1 beta were significantly elevated in Crohn's disease and ulcerative colitis cells and biopsies, and a weak but significant correlation existed between values derived from the two sources. In contrast, only ulcerative colitis cell isolates but not biopsies contained significantly reduced concentrations of IL-2 mRNA compared to those of control and Crohn's disease samples, and no correlation was found between cell and biopsy contents. Widely different levels of cytokine-specific mRNA were present in closely adjacent biopsies, particularly for IL-2. These results suggest that mucosal biopsies are suitable to assess some but not all cytokine-specific mRNA due to variation in RNA recovery, intrinsic level of cytokine gene expression, and substantial variability of cytokine transcripts.

Adolescent↗
PubMed1992

Iron overload in Africa. Interaction between a gene and dietary iron content.

BACKGROUND AND METHODS: In contrast to hemochromatosis, which in white populations is inherited through a gene linked to the HLA locus, iron overload in sub-Saharan Africa is believed to result solely from increased dietary iron derived from traditional home-brewed beer. To examine the hypothesis that African iron overload also involves a genetic factor, we used likelihood analysis to test for an interaction between a gene (the hypothesized iron-loading locus) and an environmental factor (increased dietary iron) that determines transferrin saturation and unsaturated iron-binding capacity. We studied 236 members of 36 African families chosen because they contained index subjects with iron overload. Linkage to the HLA region was tested with use of lod scores. RESULTS: In the index subjects, increased iron was present in both hepatocytes and cells of the mononuclear-phagocyte system. Among family members with increased dietary iron due to the consumption of traditional beer, transferrin saturation in serum was distributed bimodally, with 56 normal values (less than 60 percent saturation) and 44 elevated values; the mean serum ferritin concentration was five times higher in the subjects with elevated transferrin saturation (P less than 0.005). The pedigree analysis provided evidence of both a genetic effect (P less than 0.005) and an effect of increased dietary iron (P less than 0.005) on transferrin saturation and unsaturated iron-binding capacity. In the most likely model, increased dietary iron raised the mean transferrin saturation from 30 to 81 percent and lowered the mean unsaturated iron-binding capacity from 38 to 13 mumol per liter in subjects heterozygous for the iron-loading locus. The hypothesis of tight linkage to HLA was rejected. CONCLUSIONS: Iron overload in Africa may be caused by an interaction between the amount of dietary iron and a gene distinct from any HLA-linked gene.

Adult↗
PubMed1992

Young children's idiom comprehension: trying to get the picture.

Young children (3.5-6.5 years of age) were tested for their comprehension of 10 common idioms in context and no-context conditions. Results revealed a significant linear trend for children to make more literal responses with increasing age. Children of this age did not find the story contexts helpful in interpreting the idioms. A range of comprehension scores was found among the individual idioms, but semantic transparency (as judged by adults) was not related to comprehension. Child-internal and methodologic variables influencing idiom comprehension are discussed.

Child↗
PubMed1992

Distribution of HLA-DQA1, -DQB1 and DRB1 alleles in black IDDM patients and controls from Zimbabwe.

We have used the XI Histocompatibility Workshop sequence-specific oligonucleotide probes to determine the DRB1, DQA1 and DQB1 genotypes by dot-blot hybridization of polymerase chain reaction (pcr)-amplified material from a homogenous black population in Zimbabwe. The DR4 subtype DRB1*0405, the DR3 subtype DRB1*0301, DQB1*0201 and DQB1*0302 and DQA1*0301 and DQA1*0501 were significantly increased in the IDDM group compared to the controls, whereas DRB1*11, DQB1*0602 and DQA1*0102 were significantly decreased. Taken together, the data show that susceptibility and resistance to IDDM are associated both with particular haplotypes and DQA1-DQB1 heterodimers without one or other being overriding.

Adult↗
PubMed1990

HLA frequencies in black Zimbabweans.

One-hundred-and-nineteen normal Black Zimbabweans were typed for HLA antigens. We found a close similarity between the HLA antigen frequencies in Zimbabweans and Black South Africans (Xhosa), another Bantu-speaking group. The only significant differences noted were for HLA-Aw36, -Bw53, -Cw6, -DR4 and -DQw3 (p less than 0.01). The most common HLA haplotypes in significant positive linkage disequilibrium in the two groups were different. The differences that were noted may be due to gene flow from the San to the Black South Africans, since it is thought that the Zimbabweans had little if any contact with the San.

Black People↗
PubMed1990

The association between HLA and rheumatoid arthritis in Zimbabwean blacks.

HLA-A, B, C, DR and DQ typing was done on 26 black Zimbabweans with rheumatoid arthritis and the respective antigen frequencies were compared with those in a group of 119 normal individuals from the same ethnic background. Only the DR4 antigen was significantly increased in frequency in the patients, confirming the association with this disease seen in other Black African populations.

Arthritis, Rheumatoid↗
PubMed1990

The spondyloarthropathies in Zimbabwe: a clinical and immunogenetic profile.

Spondyloarthropathies are rare in Africa and there is little data regarding HLA association. We prospectively studied 19 patients with spondyloarthropathy, recording clinical details and performing tissue typing (ABC loci). There were 9 patients with ankylosing spondylitis (8 males), all had severe spinal disease but none had ocular or cardiac involvement and HLA-B27 antigen was not found in any of the 7 patients tested; only one patient possessed a B7 crossreacting antigen. The 10 patients with Reiter's syndrome (8 males) had typical clinical features but again the HLA-B27 tissue type was not found. B7-CREG antigen was found in 7 of the 10 patients with Reiter's syndrome.

Adult↗
PubMed1989

Further characterization of the neurofunctional effects of the calcium ionophore A23187.

Calimycin (A23187), a divalent cationic ionophore which increases intraneuronal concentrations of calcium, has been shown to produce neurofunctional changes associated with depression of brain excitability. The present report describes further characterization of the neurofunctional effects of acute parenteral exposure to A23187. Adult male rats were tested for the effects of A23187 on operant performance and general motor activity. In order to gain some insight into the neuronal systems which may be affected by A23187, brain levels of norepinephrine (NE), dopamine, serotonin, and their metabolites were determined. In addition, provocative pharmacologic challenges were employed to assess the interaction between A23187 and the centrally active drugs amphetamine (AMPH), scopolamine (SCOP), or chlorpromazine (CPZ). A23187 was found to effectively suppress fixed ratio-15 operant performance (p less than 0.001) at a dose of 0.5 mg/kg. This effect was temporary in nature inasmuch as performance was normalized by the day after dosing. This same dose of A23187, which produces a selective hypomotility, was found to have no apparent latent effects on the processes controlling circadian motor activity. Neurochemically, A23187 at 1 mg/kg induced a 64% increase (p less than 0.01) in the NE metabolite 3-methoxy-4-hydroxyphenylglycol, although levels of NE were unaffected. In the pharmacological challenge studies, AMPH and SCOP both attenuated and CPZ enhanced the acute hypomotility induced by 0.5 mg A23187/kg. The data show that low doses of A23187 induce a specific pattern of neurobehavioral dysfunction which may involve some interaction between the central catecholaminergic and cholinergic systems.

Animals↗
PubMed1989

Tumors of the pharyngomaxillary space.

A bulging of the soft palate should alert one to the possibility of a mass in the pharyngomaxillary space. Work-up includes CT scan or MRI and possible needle aspiration. Open biopsy should be avoided. Benign, mixed tumors are most commonly encountered. Surgical excision by external approach is generally advocated.

Adenoma↗
PubMed1983

Computerization of foot and mouth disease virus strain relationship data.

Since 1976 the two dimensional microneutralization test has been adopted in our laboratory as the reference test for foot and mouth disease virus (FMDV) strain differentiation. Large numbers of homologous-heterologous comparisons have been performed and manual storage and retrieval of the data had become cumbersome. The objective of computerization was to provide a databank with fast easy access to enable accurate statistical calculations to be performed on the raw data entries and to simplify the evaluation of statistical and biological significance. The computer system is written in Fortran for an IBM 4341 computer running under the VM/CMS operating system.

Animals↗
PubMed1982

Necessary and sufficient conditions for Von Kries chromatic adaptation to give color constancy.

Necessary and sufficient spectral conditions are presented for Von Kries chromatic adaptation to give color constancy. Von-Kries-invariant reflectance spectra are computed for illuminant spectral power distributions that are arbitrary linear combinations of the first three daylight phases. Experiments are suggested to test models of color constancy using computed spectra (either exact or approximate) within the illuminant-invariant framework.

Color↗
PubMed1982

A peritoneal fluid activator for histamine release from isolated peritoneal mast cells of the rat.

A factor present in rat peritoneal fluid has been found to be necessary for optimal release of histamine from peritoneal mast cells by dextran and antigen, but not by concanavalin A. Washed peritoneal mast cells suspended in a physiological medium containing bovine serum albumin require ten-fold higher concentrations of phosphatidyl serine for optimal release by concanavalin A. The peritoneal fluid activator is probably a protein of molecular weight about 180,000 Daltons.

Animals↗