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Biomedical subjects

D Meyers

Publications and source records attributed to D Meyers.

At least 37 records · Page 2Linked to original sources
PubMed1994

Sequential strategy to identify a susceptibility gene for schizophrenia: report of potential linkage on chromosome 22q12-q13.1: Part 1.

To identify genes responsible for the susceptibility for schizophrenia, and to test the hypothesis that schizophrenia is etiologically heterogeneous, we have studied 39 multiplex families from a systematic sample of schizophrenic patients. Using a complex autosomal dominant model, which considers only those with a diagnosis of schizophrenia or schizoaffective disorder as affected, a random search of the genome for detection of linkage was undertaken. Pairwise linkage analyses suggest a potential linkage (LRH = 34.7 or maximum lod score = 1.54) for one region (22q12-q13.1). Reanalyses, varying parameters in the dominant model, maximized the LRH at 660.7 (maximum lod score 2.82). This finding is of sufficient interest to warrant further investigation through collaborative studies.

Adult↗
PubMed1994

Follow-up of a report of a potential linkage for schizophrenia on chromosome 22q12-q13.1: Part 2.

A collaboration involving four groups of investigators (Johns Hopkins University/Massachusetts Institute of Technology; Medical College of Virginia/The Health Research Board, Dublin; Institute of Psychiatry, London/University of Wales, Cardiff; Centre National de la Recherche Scientifique, Paris) was organized to confirm results suggestive of a schizophrenia susceptibility locus on chromosome 22 identified by the JHU/MIT group after a random search of the genome. Diagnostic, laboratory, and analytical reliability exercises were conducted among the groups to ensure uniformity of procedures. Data from genotyping of 3 dinucleotide repeat polymorphisms (at the loci D22S268, IL2RB, D22S307) for a combined replication sample of 256 families, each having 2 or more affected individuals with DNA, were analysed using a complex autosomal dominant model. This study provided no evidence for linkage or heterogeneity for the region 22q12-q13 under this model. We conclude that if this region confers susceptibility to schizophrenia, it must be in only a small proportion of families. Collaborative efforts to obtain large samples must continue to play an important role in the genetic search for clues to complex psychiatric disorders such as schizophrenia.

Adult↗
PubMed1989

Computer methods for sampling, reconstruction, display and analysis of retinal whole mounts.

We are quantifying the distribution of photoreceptors and ganglion cells in human retina with the goal of establishing a reliable anatomical database which may be compared to information about visual function. We required a representation of retinal cell distributions which facilitated collection, analysis, and display of morphometric data from the entire retina of a large number of eyes. We report computer methods to (1) reconstruct the original retinal sphere from a three-piece whole mount preparation; (2) sample the retina in a manner which allowed description of approximately radially symmetrical cell distributions and avoided both undersampling (which produces interpolation artifacts) and oversampling (which wastes time); (3) interpolate between data points in order to produce plots of cell density along arbitrary meridians and maps of average cell density from several eyes; (4) specify locations on the retinal surface using a spherical coordinate system with its primary axis through the fovea; and (5) produce color-coded maps of cell distributions in a standard perimetric projection.

Cell Count↗
PubMed1989

Crustacean peptidergic neurons in culture show immediate outgrowth in simple medium.

The survival and outgrowth of neurons in culture has usually required conditioning factors. We now report that crustacean neurons, taken from the peptidergic neurosecretory system of the eyestalk of crabs (Cardisoma carnifex) and lobsters (Panulirus marginatus), show immediate outgrowth, sustained for a week or more, in defined medium as simple as physiological saline with glucose and glutamine. The neurons show peptide hormone immunoreactivity that is prominent at growth cones, exhibit differences in form correlated with their immunoreactivity, release peptides to the medium, and have voltage-dependent currents, including a well-sustained Ca current. Cd blocks secretion, growth, and the Ca current. Peptidergic secretory neurons may be able to utilize existing membrane from their store of granules and already active synthetic, transport, and secretory mechanisms for immediate outgrowth.

Animals↗
PubMed1989

Collagen synthesis by normal and fibrotic human lung fibroblasts and the effect of transforming growth factor-beta.

Collagen accumulation is a major feature of pulmonary fibrosis and other fibrotic lesions. We have studied the synthesis of collagens in fibroblasts cultured from normal and fibrotic human lung specimens and evaluated how it is affected by transforming growth factor-beta (TGF-beta). Fibroblasts were obtained from normal and fibrotic adult human lungs (n = 11; normal = 6, idiopathic pulmonary fibrosis = 5). They were exposed to TGF-beta and pulse-labeled with [3H]proline and [3H]glycine. Collagen production was measured as bacterial collagenase-susceptible radioactivity, and collagen mRNA levels were determined by a solution hybridization assay using labeled procollagen alpha 1[I] cDNA clone HF677 as probe. Synthesis of collagen types I, III, and V were assessed after separating them by DEAE-cellulose chromatography and SDS-polyacrylamide gel electrophoresis. The results showed that both normal and fibrotic lung fibroblasts synthesized similar amounts of collagen. Type I was the major collagen species synthesized by both normal and fibrotic cell types, and the relative proportion of type I, III, and V collagens was similar in both cell types. TGF-beta caused a two to fourfold increase in stimulation of collagen production and collagen mRNA levels, and no differences were detected in the response of normal and fibrotic lung fibroblasts. All collagen types were stimulated by the TGF-beta. TGF-beta did not increase fibroblast proliferation and the majority of normal and fibrotic lung cells exposed to TGF-beta remained in G1 phase of the cell cycle. We conclude that fibroblasts of normal and fibrotic human synthesize similar amounts of collagens.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1987

In vivo studies with two phospholipase C fractions from Pseudomonas aeruginosa.

Two phospholipase C fractions were detected in culture supernatants from Pseudomonas aeruginosa ATCC 19660, PAO1, and D10C by preparative polyacrylamide gel electrophoresis. Both hemolytic fractions from strain ATCC 19660 were isolated by polyacrylamide gel electrophoresis and were found to cause paralysis, death, dermonecrosis, footpad swelling, and vascular permeability in mice. In vivo toxicity was directly associated with enzymatic activity.

Animals↗
PubMed1984

Principal-components analysis of prehistoric South Asian crania.

Principal-components analysis is used as an investigative procedure for establishing temporal, spatial and evolutionary-developmental changes in Homo sapiens skeletal specimens from prehistoric sites in South Asia. It is concluded that cranial variables which cluster hunter-gatherers within the sample are related to facial architecture with respect to robusticity and size. Older models presumably reflecting genetic affinities and racial classifications of prehistoric South Asians which were based upon univariate-bivariate statistical analyses are not supported by the results of this principal-components analysis.

Asia, Western↗