Search PubMed⌕ Search

Biomedical subjects

J H Parker

Publications and source records attributed to J H Parker.

At least 19 recordsLinked to original sources
PubMed1985

Amerlex free triiodothyronine and free thyroxine levels in normal pregnancy.

Free triiodothyronine (FT3) and free thyroxine (FT4) were measured in 159 women during normal pregnancy and compared with non-pregnancy reference ranges for these hormones. FT3 values fell from the reference level of 6.34 (SD 1.06) pmol/l to 3.87 (SD 0.54) pmol/l in the 3rd trimester; corresponding figures for FT4 were: reference 16.92 (SD 2.97) pmol/l, 3rd trimester 11.29 (SD 2.01) pmol/l. There were no significant changes in the 1st trimester; 4% and 69% of FT3 results in the 2nd and 3rd trimesters respectively fell below the reference range of mean +/- 2 SD. The corresponding findings for FT4 were 4% and 42%. FT3 correlated reasonably well with total T3 (r = 0.90) and was acceptably precise (within-batch CV 2.1% at 5.6 pmol/l, between-batch CV between 3.1% and 4.7% at six levels).

Female↗
PubMed1982

Tooth attrition and continuing eruption in a Romano-British population.

Cement-enamel junction to alveolar crest (CEJ-AC) distances were measured in Romano-British skulls. Measurements were also made of attrition patterns. The patterns of the two measurements were similar in each group, suggesting that teeth continued to erupt and CEJ-AC alone is misleading as a measurement of bone loss and may not relate to the extent of chronic inflammatory periodontal disease. Estimated bone loss was minimal, confirming that measurements of this nature on dried skulls should only be related to periodontal conditions with caution.

Adolescent↗
PubMed1982

Sensitive assay, based on hydroxy fatty acids from lipopolysaccharide lipid A, for Gram-negative bacteria in sediments.

Biochemical measures have provided insight into the biomass and community structure of sedimentary microbiota without the requirement of selection by growth or quantitative removal from the sediment grains. This study used the assay of the hydroxy fatty acids released from the lipid A of the lipopolysaccharide in sediments to provide an estimate of the gram-negative bacteria. The method was sensitive to picomolar amounts of hydroxy fatty acids. The recovery of lipopolysaccharide hydroxy fatty acids from organisms added to sediments was quantitative. The lipids were extracted from the sediments with single-phase chloroform-methanol extraction. The lipid-extraction residue was hydrolyzed in 1 N HCl, and the hydroxy fatty acids of the lipopolysaccharide were recovered in chloroform for analysis by gas-liquid chromatography. This method proved to be about fivefold more sensitive than the classical phenol-water or trichloroacetic acid methods when applied to marine sediments. By examination of the patterns of hydroxy fatty acids, it was also possible to help define the community structure of the sedimentary gram-negative bacteria.

Bacillus subtilis↗
PubMed1978

Prognosis in schizophrenia. Prognostic predictors and outcome.

Eighty-eight of 92 first-admission schizophrenics from 1963, an incidence by first admission cohort, were followed up in 1974 and 1975. Epidemiologically the sample was more comparable to lower European rates and expectancy rather than to higher American figures. Prior to follow-up, factors said to predict outcome were scored. This prognostic information was complete for 79 cases. Outcome was measured on a variety of criteria. The patients fell into a "poor prognosis" group based on the prognostic indicators, which were of little value in predicting prognosis within this group. However, patients who received extensive service during the follow-up period had poorer outcomes. Outcome was better than in most earlier studies of schizophrenia, but similar to that in some other recent studies of first-admission patients; also, the use of phenothiazines, short-term hospitalization, and community services may play a part. The failure of prognostic indicators to predict more than about 25% of the outcome variance for this group of "poor prognosis" patients supports the viewpoint that "good" and "poor" prognosis schizophrenia are two different entities.

Adolescent↗
PubMed1978

D-Lyxose as a substrate for Streptomyces D-xylose isomerase.

Results are presented which show that the D-xylose isomerases present in Streptomyces olivaceus and Streptomyces phaeochromogenes NRRL B-3559 are incapable of utilizing D-lyxose as a substrate. The implications of these findings as related to the use of D-lyxose in the selection of constitutive mutants are discussed.

Carbohydrate Epimerases↗
PubMed1976

Prognosis in schizophrenia. A ten-year follow-up of first admissions.

Eighty-eight of 92 first admission schizophrenics from 1963, being an incidence by first admission cohort, were followed up between 1974 and 1975. Fifty-eight percent were reported as showing no social or intellectural deficit, and only 8% were unremitting institutionalized, with 51% being considered as having normal economic productivity, and 69% with a good or fair social adjustment. Despite difficulties in comparison, birth, marriage, and divorce rates appear to be not very different from those for the general population, although the percentage of married patients is lower. Deaths would seem greater than expected. Possible reasons for the improved prognosis in schizophrenia are considered to be short initial hospitalization, almost universal use of phenothiazines, use of developing community services (social and psychiatric), and generally good econimic conditions.

Adolescent↗
PubMed1974

Mutants of yeast defective in iso-1-cytochrome c.

A medium containing chlorolactate has been devised to enrich for mutants that are unable to utilize lactate for growth, and therefore that may be defective in cytochrome c. Complementation tests of 6,520 chlorolactate-resistant mutants that were obtained spontaneously or induced with UV, ICR-170, or nitrosoimidazolidone resulted in the identification of 195 mutations at the cyc1 locus, which controls the primary structure of iso-1-cytochrome c. These 195 mutants, with 16 cyc1 mutants previously isolated, were examined for total cytochrome c by spectroscopic methods, growth on lactate medium, suppressibility by defined nonsense suppressors, mutational sites by x-ray-induced recombination, ability to revert, and in 86 cases, whether intragenic revertants contain altered iso-1-cytochrome c. Except for the deletion mutant cyc1-1, all of the mutants appeared to contain single-site mutations that could be assigned to at least 35 different sites within the gene. The cyc1 mutants either completely lacked iso-1-cytochrome c or contained iso-1- cytochromes c that were completely or partially nonfunctional. In spite of the fact that the cyc1 mutants obtained by the chlorolactate procedure were selected on the basis of defective function, 68% appeared to completely lack iso-1-cytochrome c. The remaining cyc1 mutants contained below normal amounts of iso-1-cytochromes c. Studies at several incubation temperatures indicated that these nonfunctional iso-1-cytochromes c were thermolabile. It is suggested that the predominant means for abolishing iso-1-cytochrome c by mutations are either through a complete loss, such as produced by chain terminating codons, or impairments through drastic changes of tertiary structure which lead to instability and thermolability.

Acridines↗
PubMed1971

Circumcision.

Explore the source record for details and available documents.

Australia↗