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Biomedical subjects

J W James

Publications and source records attributed to J W James.

At least 19 recordsLinked to original sources
PubMed2006

A pedigree-analysis approach to the descriptive epidemiology of autosomal-recessive disorders.

We describe a pedigree-analysis approach to estimating descriptive epidemiological parameters for autosomal-recessive disorders when the ancestral source of the disorder is known. We show that the expected frequency of carriers in a cohort equals the gene contribution of the ancestral source to that cohort, which is equivalent to the direct (additive) genetic relationship of that ancestor to the cohort. Also, the expected incidence of affected foetuses ranges from (1/2)F* to F*, where F* is the mean partial inbreeding coefficient (due to the ancestor) of the cohort. We applied this approach to complex vertebral malformation (CVM) in Holstein-Friesians in Australia, for which the ancestral source is a USA-born bull, Carlin-M Ivanhoe Bell. The estimated frequency of carriers was 2.47% for the 1992-born and 4.44% for the 1997-born cohort of Holstein-Friesian cows in Australia. The estimated incidence of affected foetuses/calves was considerably less than one per thousand, ranging from 0.0024 to 0.0048% for the 1992-born cohort, and from 0.0288 to 0.0576% for the 1997-born cohort. These incidences correspond to expected numbers of affected female foetuses/calves ranging from 2 to 4 for the 1992-born cohort and from 28 to 56 for the 1997-born cohort. This approach is easy to implement using software that is readily available.

Animals↗
PubMed2000

A novel approach to the assessment of variations in the human platelet count.

This is the first report of a method to assess the significance of numerical changes in the platelet count based upon a result exceeding the normal intra-individual variation in platelet numbers. Serial platelet counts from 3,789 subjects were analysed to determine the intra-individual variation in platelet numbers. A platelet count difference of 98 x 10(9)/L in males was found to represent a change that would occur by chance in less than 1 in 1,000 platelet count determinations. Tables to determine the significance of platelet number variations, given N previous observations, are provided at two probability levels. The repeatability of the platelet count was calculated as 0.871 (males) and 0.849 (females) indicating that the heritability of platelet count is high and that the platelet count is predominantly genetically determined. A seasonal variation in platelet count was found with a 'winter' versus 'summer' difference of 5.10 X 10(9)/L (males) and 5.82 x 10(9)/L (females).

Analysis of Variance↗
PubMed1995

Age and health bias in practicing clinical psychologists.

Although ageism is widely cited as a problem in mental health delivery, it is unknown whether practitioner biases are related to factors such as physical health. A randomly drawn national sample of experienced practicing doctoral-level psychologists (N = 371) responded to detailed vignettes of a client presenting with symptoms of depression, in which age (35 years or 70 years) and health (unremarkable or poor) were manipulated. Respondents completed ratings involving professional and interpersonal judgments about the hypothetical client. Results revealed some evidence for age bias, but much stronger effects indicating health biases regardless of client age. Because depressed older persons often present with concomitant health problems, health bias among clinicians is especially relevant for older patients. Implications for service delivery to older adults, and individuals with health problems, are discussed.

Adjustment Disorders↗
PubMed1979

Allozyme genotype--environment relationships in natural populations of Drosophila buzzatii.

Allozyme frequency data from natural populations of Drosophila buzzatii were analyzed for genotype--environment relationships. Allele frequency and heterozygosity at six loci polymorphic throughout eastern Australia and a number of environmental factors (both means and variabilities) were examined by a variety of multivariate techniques. Significant genotype--environment associations were found for five of the six loci, and after correcting for geographic location significant associations remained for Est-2 and Adh-1 gene frequencies and heterozygosities and for Pgm gene frequencies. The results are discussed in relation to selection and gene flow and provide the basis for laboratory studies to disentangle confounded effects of (1) environmental means and environmental variabilities and (2) allele frequency and heterozygosity, and thus to further test for and determine the nature of any natural selection at particular allozyme loci.

Alleles↗
PubMed1978

A note on the essential parameters of the two-allele autosomal locus model.

A resolution of the parameter problem for the two-allele autosomal locus (TAAL) model has been presented. It was shown that three are four essential parameters which describe the model, by examination of the joint probability for sibs with specified parental phenotypes. This equation together with previously derived prevalence relationships uniquely specifices all parameters of the model except for the singular case VA = 0.

Alleles↗
PubMed1970

Use of oral mannitol in the oedematous patient.

Oral mannitol 200 g. was given on 24 occasions to patients with intractable oedema (cardiac, renal, or hepatic) and produced a mean weight loss of 3 kg. The procedure was found to be a safe, rapid, and effective method of treating oedema, and it should be used when diuretic therapy proves ineffective, particularly in the presence of hyponatraemia.

Administration, Oral↗