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Biomedical subjects

R White

Publications and source records attributed to R White.

At least 559 records · Page 31Linked to original sources
PubMed1988

DERM/INFONET: a concept becomes a reality.

The DERMatology INFOrmation NETwork (DERM/INFONET) of the American Academy of Dermatology has become a reality. DERM/INFONET consists of a number of data bases providing information and educational programs for the dermatologist. Currently the components are: DERM/MLS (Medical Literature Search), DERM/RX (dermatologic therapy), DERM/USP (United States Pharmacopeia data base), DERM/ALLERGENS (Food and Drug Administration and Environmental Protection Agency Listings of allergens); Melanoma Prognosis Model; Electronic Mail; Bulletin Board; Meetings Calendar; ICD/CPT (International Classification of Diseases/Current Procedural Terminology) codes; AAD Membership/Committee Directories; and Dermatology Quiz. Additional data bases are planned. As audiovisual and alphanumeric communication systems evolve, newer opportunities for enhancing the DERM/INFONET Biomedical Communication Network will undoubtedly provide even greater opportunities for aiding the dermatologist in delivering state-of-the art management for their patients.

Computer Communication Networks↗
PubMed1988

Chromosome mapping with DNA markers.

New markers called RFLP's (for restriction-fragment length polymorphisms) can indicate the location on a chromosome of a disease-causing gene and serve to identify carriers. With enough markers one can map the human chromosomes--the first step toward an ambitious goal of molecular biology: sequencing the entire human genome.

Alleles↗
PubMed1988

Rapid identification of cytomegalovirus in liver allograft biopsies by in situ hybridization.

Identifying the etiology of hepatic dysfunction in liver transplant patients is critical to their clinical management and in maintaining graft survival. While cytomegalovirus (CMV) is a well-known cause of posttransplant hepatitis, the morphologic diagnosis of CMV hepatitis in liver biopsies can be difficult. Because conventional tissue culture for CMV requires days to weeks, the final results often arrive too late to be clinically useful. In this study, 44 liver allograft biopsies from 21 patients with hepatic dysfunction were evaluated for CMV by routine light microscopy, conventional tissue culture, and in situ DNA hybridization (IH) using commercially available biotinylated CMV-specific DNA probes. Whereas 38.6% of the biopsy specimens were positive by IH, 15.9% were culture-positive biopsies and 13.6% were positive by routine light microscopy. Assuming tissue culture to be the standard, IH demonstrated a sensitivity of 100% and a specificity of 73%. In comparison, routine light microscopy showed a sensitivity of 71.4% and specificity of 97.3%. In addition, three biopsy specimens positive only by IH were from three patients who had other liver biopsies positive for CMV by either light microscopy or viral culture. In situ DNA hybridization allows rapid detection (5-6 h) of CMV in paraffin-embedded liver allograft biopsies; it also has a sensitivity that surpasses routine histologic examination and perhaps even tissue culture.

Adolescent↗
PubMed1988

VNTR (variable number of tandem repeats) markers show loss of chromosome 17p sequences in human colorectal carcinomas.

Restriction fragment length polymorphisms at 53 autosomal loci were screened for heterozygosity in 40 colorectal cancer patients. The DNA pattern in constitutional versus tumor/polyp tissue was compared. More than half of the markers tested were of the VNTR (variable number of tandem repeats) type, giving the patient panel a higher informational content, since the frequency of individuals heterozygous for a particular marker is increased. Loss of alleles was revealed in 40% of the tumors from constitutionally heterozygous patients at the chromosome 17p loci, identified by the markers YNH37 and YNZ22. Similar losses were also detected on other autosomes, but at a significantly lower frequency. Our results suggest that hemi/homozygosity of 17p alleles plays a role in the development of a major subset of colorectal carcinomas. Similar observations regarding other autosomal loci may be interpreted as random losses in these tumors, or they may indicate loci important to minor clinical subclasses of colon carcinomas.

Carcinoma↗
PubMed1988

Inference of a molecular defect of apolipoprotein B in hypobetalipoproteinemia by linkage analysis in a large kindred.

Heterozygous hypobetalipoproteinemia is characterized by reduced plasma concentrations of LDL cholesterol, total triglycerides, and apo B to less than 50% of normal values. The molecular basis of this disorder remains unknown. The phenotype cosegregates with a DNA haplotype of the apo B gene in an Idaho pedigree, with a maximum decimal logarithm of the ratio (LOD) score of 7.56 at a recombination rate of zero. Individuals carrying this haplotype had total cholesterol levels of 96 mg/dl, LDL cholesterol levels of 37 mg/dl, triglycerides levels of 51 mg/dl, and apo B levels of 38 mg/dl. This study strongly suggests that apo B mutations underlie hypobetalipoproteinemia, and demonstrates the power of the candidate gene approach in linkage analysis for unraveling genetic determinants in metabolic disorders of undefined etiology.

Adolescent↗
PubMed1988

Oleate uptake by cardiac myocytes is carrier mediated and involves a 40-kD plasma membrane fatty acid binding protein similar to that in liver, adipose tissue, and gut.

Uptake of [3H]oleate by canine or rat cardiac myocytes is saturable, displays the countertransport phenomenon, and is inhibited by phloretin and trypsin. Cardiac myocytes contain a basic (pI approximately 9.1) 40-kD plasma membrane fatty acid binding protein (FABPPM) analogous to those recently isolated from liver, adipose tissue, and gut, unrelated to the 12-14-kD cytosolic FABP in these same tissues. An antibody to rat liver FABPPM selectively inhibits specific uptake of [3H]oleate by rat heart myocytes at 37 degrees C, but has no influence on nonspecific [3H]oleate uptake at 4 degrees C or on specific uptake of [3H]glucose. Uptake of long-chain free fatty acids by cardiac muscle cells, liver, and adipose tissue and absorption by gut epithelial cells is a facilitated process mediated by identical or closely related plasma membrane FABPs.

Adipose Tissue↗
PubMed1988

Detection of a NotI polymorphism with the pmetH probe by pulsed-field gel electrophoresis.

The pmetH probe, tightly linked to the locus for cystic fibrosis (CF), detected a NotI polymorphism with allele sizes of 1,000 and 550 kb that could be separated by pulsed-field gel electrophoresis. Both alleles were found on chromosomes bearing either the normal or the CF allele. Preliminary data showed that this polymorphism was not in strong linkage disequilibrium with the CF locus. Preliminary large-scale restriction mapping of the fragment showed that the NotI polymorphic site is 200-370 kb distant from the MET locus; thus it defines a new polymorphic locus in the CF region. This locus is of potential interest for studying CF families that show recombinants between CF and its tightly linked probes, in order to increase the precision of the genetic map of the region.

Chromosome Mapping↗
PubMed1988

New approach for isolation of VNTR markers.

Elsewhere we have reported an efficient method for isolating VNTR (Variable Number of Tandem Repeats) markers. Several of the VNTR markers isolated in those experiments were sequenced, and a DNA sequence of 9 bp (GNNGTGGG) emerged as an apparent consensus sequence for VNTR markers. To confirm this result and to develop more VNTR markers, we synthesized nine different 18-base-long oligonucleotides whose sequences each included GNNGTGGG. When 102 cosmid clones selected by these oligonucleotides were tested for polymorphism, 34 (33%) of them showed multiallelic VNTR polymorphisms (average heterozygosity 68%). This procedure represents a new and efficient approach for isolating additional VNTR markers and supports the idea that the GNNGTGGG sequence may play an important role in the generation of the multiallelic systems within the human genome.

Blotting, Southern↗