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Biomedical subjects

R H Adams

Publications and source records attributed to R H Adams.

At least 19 recordsLinked to original sources
PubMed1995

Murine semaphorin D/collapsin is a member of a diverse gene family and creates domains inhibitory for axonal extension.

Members of the collapsin/semaphorin gene family have been proposed to act as growth cone guidance signals in vertebrates and invertebrates. To identify candidate molecules involved in axonal pathfinding during mouse embryogenesis, we isolated cDNAs encoding five new members of the semaphorin family (Sem A-Sem E). The murine semaphorin genes are differentially expressed in mesoderm and neuroectoderm before and during the time when axons select their pathways in the embryo. In explant cultures, recombinant Sem D/collapsin converts a matrix permissive for axonal growth into one that is inhibitory for neurites of peripheral ganglia. Our data demonstrate that semaphorins are a diverse family of molecules that may provide local signals to specify territories nonaccessible for growing axons.

Amino Acid Sequence↗
PubMed1995

Gene structure and glial expression of the glycine transporter GlyT1 in embryonic and adult rodents.

Na+/Cl(-)-dependent glycine transporters are crucial for the termination of neurotransmission at glycinergic synapses. Two different glycine transporter genes, GlyT1 and GlyT2, have been described. Several isoforms differing in their 5' ends originate from the GlyT1 gene. We have determined the genomic structure of the murine GlyT1 gene to elucidate the genetic basis underlying the different isoforms. Analysis of cDNA 5'-ends revealed that the GlyT1a and 1b/1c mRNAs are transcribed from two different promoters. During murine embryonic development GlyT1 mRNAs were detectable by RNase protection assays as early as embryonic day E9 and reached maximal levels between E13 and E15. In situ hybridization revealed GlyT1 expression in the developing spinal cord mainly in the ventral part of the ventricular zone at E12. At later stages (E15) transcripts were also found in the lateral half of the basal and intermediate gray matter. In contrast, the second glycine transporter gene GlyT2 displayed a completely different expression pattern. At E11 it is expressed in the mantle zone, and at later stages throughout the ventral horns. In the adult rat brain and spinal cord, GlyT1 hybridization signals were found exclusively in glial cells. Our data indicate that GlyT1 is an early marker of neural development and encodes glia-specific transporter proteins.

Amino Acid Sequence↗
PubMed1992

Construction of a 3-chlorobiphenyl-utilizing recombinant from an intergeneric mating.

Recombinant Pseudomonas sp. strain CB15, which grows on 3-chlorobiphenyl (3CB), was constructed from Pseudomonas sp. strain HF1, which grows on 3-chlorobenzoate, and from Acinetobacter sp. strain P6, which grows on biphenyl, by using a continuous amalgamated culture apparatus. DNA from strains CB15 and HF1 hybridized very strongly to each other, while hybridization between both parental strains, HF1 and P6, was negligible. However, DNA from the recombinant CB15 hybridized moderately to strongly with three specific fragments of parental strain P6. Strains HF1 and P6 did not grow on 3CB, but recombinant strain CB15 mineralized this compound and released inorganic chloride. When growing on 3CB, strain CB15 accumulated brown products, one of which was identified as 3-chloro-5-(2'-hydroxy-3'-chlorophenyl)-1,2-benzoquinone by mass spectrometry. Emulsification and mechanical fragmentation greatly increased the rate of 3CB mineralization by strain CB15. At least three methods of inhibition from catecholic intermediates may account for slow growth on 3CB. The meta fission of 2,3-dihydroxybiphenyl (the nonchlorinated analog of the metabolic intermediate 3-chloro-2',3'-dihydroxybiphenyl) was affected by substrate inhibition (Vmax = 359 nmol.min-1.mg-1, Km = 114 microM, Kss [the inhibition constant] = 951 microM) and was also inhibited by 3-chlorocatechol. The ortho fission of 3-chlorocatechol, a degradation product, followed Michaelis-Menten kinetics (Vmax = 365 nmol.min-1.mg-1, Km = 1 microM), but the addition of 2,3-dihydroxybiphenyl inhibited the reaction (Ki = 0.87 microM).(ABSTRACT TRUNCATED AT 250 WORDS)

Acinetobacter↗
PubMed1989

Interstitial deletion of chromosome 5, del(5q), in a newborn with Down syndrome and an unusual hematologic disorder.

A newborn with Down syndrome was noted on the 1st day of life to have an elevated white blood cell count of 79,900/mm3 with 62% lymphoblasts and a platelet count of 61,000/mm3, consistent with either transient myeloproliferative disorder of Down syndrome (TMD) or acute leukemia. Karyotype analysis of a bone marrow aspirate revealed that 20% of the cells had a 47,XY, +21 karyotype, and 80% had a 47,XY, +21, del(5)(q13q31) complement. Cytochemical and immunophenotyping of the peripheral blasts were consistent with the presence of an acute undifferentiated precursor blast clone. Results of clonogenic assays of hematopoietic progenitors from this patient's bone marrow were similar to those of patients with TMD. This patient's hematologic abnormalities resolved spontaneously without treatment by week 10 of life. This is the first report of an interstitial deletion of 5q associated with a hematologic abnormality present in an infant at birth.

Adult↗
PubMed1989

Information technology in postgraduate medical education.

Information technology in postgraduate medical education has developed rapidly over the last 5 years. This report describes the experience of setting up a computer-based information system in postgraduate centres in the West of Scotland. It includes a viewdata service, library facilities, computer-assisted learning, word processing, and statistics. An electronic mail system provides rapid communication between users. The costing and some of the problems in setting up such systems are discussed.

Education, Medical, Graduate↗
PubMed1988

Effect of actinomycin D and cycloheximide on replication of Sindbis virus in Aedes albopictus (mosquito) cells.

Production of Sindbis virus in the presence of transcription and translation inhibitors was examined in three Aedes albopictus cell lines. Addition of cycloheximide to heat-resistant Sindbis virus (SVHR)-infected mosquito cells arrested viral RNA synthesis completely, in contrast to the effects of this drug on virus-infected vertebrate cells. Production of mature virus by both SVHR (a variant commonly used as a wild-type virus) and SBamr (a mutant which is resistant to the effects of 18 h of pretreatment of vertebrate cells with actinomycin D) in mosquito u4.4, C6-36, and C7-10 cells was inhibited by 2 h of pretreatment with actinomycin D. Pretreatment with this drug for 2 h slightly enhances virus production in vertebrate cells. Treatment of mosquito cells with actinomycin D resulted in shutoff of SVHR RNA synthesis. The mutant SBamr was able to overcome the effects of actinomycin D on viral RNA synthesis and produced both 26S and 49S RNAs, even though no viral structural proteins or mature particles were produced in the presence of the drug. This result suggests that, in the presence of actinomycin, the nonstructural genes of SBamr are translated sufficiently to allow for RNA synthesis but that 26S RNA may not be translated to an extent that allows significant virus production. These data demonstrate that host components are involved in at least two distinct steps in the production of Sindbis virus in mosquito cells: (i) production of viral RNA and (ii) synthesis of viral structural polypeptides.

Aedes↗
PubMed1986

An accident and emergency department's view of self-poisoning: a retrospective study from the United Norwich Hospitals 1978-1982.

This 5-year review of deliberate self-poisoning cases seen in an accident and emergency department revealed that about 700 patients were seen per year. Three-quarters of these needed admission (forming some 15% of all hospital admissions). Of these 65% were referred to the psychiatrist. The remaining quarter were dealt with in the accident and emergency department. Analysis of the data identifies problems where further research is needed. In particular the question is raised as to whether these patients would not be better dealt with in an acute medical unit now that accident departments are turning their attention increasingly to the management of trauma.

Adolescent↗
PubMed1985

BHK cells expressing Sindbis virus-induced homologous interference allow the translation of nonstructural genes of superinfecting virus.

The process by which Sindbis virus excludes superinfecting homologous virus was investigated with the use of temperature-sensitive mutants. Mutants in two RNA-negative complementation groups were found to be defective in their ability to establish interference at the nonpermissive temperature. These mutants were unable to establish interference in a mixed infection (complementation), suggesting that both were defective in a common gene product. Homologous interference was found to block the replication of superinfecting virus after attachment, penetration, and translation of the nonstructural genes encoded in the virus RNA. The production of nonstructural gene products of superinfecting wild-type virus was found to enhance the replication of certain RNA- temperature-sensitive interfering viruses at the permissive and the nonpermissive temperature. The ability of certain RNA- mutants to establish homologous interference and to demonstrate enhanced growth after superinfection with wild-type virus was interpreted to produce a model implicating both virus and host components in the establishment of homologous interference and in the replication of Sindbis virus RNA.

Animals↗
PubMed1984

Surgical suite reconstruction. Infection control.

Careful literature review revealed little information on the safety of using an operating room during major renovation. This study sought to determine if an operating room under renovation increases infectious morbidity in the surgical wound. The observations of this study indicate that it is possible to use a properly ventilated operating room undergoing renovation if the precautions of controlling construction traffic, sealing off the construction area from the OR in use, fastidious housekeeping, environmental culturing, and careful surveillance of wound infections are used.

Air Microbiology↗
PubMed1982

Inhibition of Sindbis virus maturation after treatment of infected cells with trypsin.

Brief treatment of Sindbis virus-infected BHK-21 or Vero cells with low concentrations of trypsin irreversibly blocked further production of progeny virions after removal of the enzyme. The inhibitory effects of the trypsin treatment could only be demonstrated in cells in which virus infection was established; optimal inhibition occurred at ca. 3 h postinfection. Production of virus structural proteins PE2, E1, and C occurred at normal levels in inhibited cells. PE2 and E1 were also transported to the cell plasma membrane during inhibition; however, PE2 was not cleaved to E2, and little capsid protein became membrane associated relative to control cells. Although trypsin treatment had no effect on Sindbis protein synthesis, the production of both 26S and 42S RNA was greatly reduced. Similar trypsin treatment of BHK cells infected with vesicular stomatitis virus had no detectable effect on the course of virus infection.

Animals↗