Search PubMed⌕ Search

Biomedical subjects

J Walker

Publications and source records attributed to J Walker.

At least 379 records · Page 21Linked to original sources
PubMed1987

Sociometric status of clinic-referred children with attention deficit disorders with and without hyperactivity.

Peer sociometric nominations of clinic-referred children given the diagnosis of Attention) Deficit Disorder with Hyperactivity (ADD/H) or Attention Deficit Disorder without Hyperactivity (ADD/WO) were compared to one another and to those of normal control children. Only children with ADD diagnoses in the absence of other major diagnoses were included. Both children with ADD/H (n = 16) and ADD/WO (n = 11) received significantly fewer "liked most" nominations, more "liked least" nominations, and lower social preference scores than normal control (n = 45) children. These results confirm previous findings of social deficits in children with ADD/H, even when codiagnoses are excluded. In addition, they support the validity of the diagnostic category of ADD/WO by demonstrating that the ADD/WO behavior pattern is apparently "psychopathological" in being associated with peer unpopularity after codiagnoses are excluded. When larger groups including all codiagnoses (primarily Conduct Disorder) of children with ADD/H (n = 36) and ADD/WO (n = 20) were compared, identical patterns of peer unpopularity were found, except that children with ADD/H also were significantly more likely to be nominated as a child who "fights most."

Attention↗
PubMed1987

Concentration dependence of the binding constant of antibodies.

By simultaneous dilution of the antigen (AG) and the antibody (AB) used in an immune precipitation reaction, at the equivalence AG/AB ratio, it was found that the association constant, Ka, increased from 1.7 X 10(7) 1/M at the highest concn of AG and AB, to 6.5 X 10(11) 1/M at 100-fold dilution of both. An important (but not the only) reason for this increase is taken to be the fact that the AB solution was polyclonal.

Antibody Affinity↗
PubMed1987

Prune belly syndrome associated with exomphalos and anorectal agenesis.

We have recently treated a child with prune belly syndrome in association with exomphalos and anorectal agenesis. This case raises the total incidence of exomphalos and anorectal agenesis to four and five, respectively, in our series of 13 cases of prune belly syndrome. Our case report lays emphasis on the severe respiratory problems that can complicate surgery in prune belly patients. We also attempt to relate the pattern of anomalies in our series to the controversy surrounding the embryogenesis of prune belly syndrome and suggest that our case material lends support to the concept of prune belly syndrome being due to an early disturbance of mesodermal development in both the abdominal wall and the urinary tract. We also suggest that the reported occurrence of gastroschisis in association with prune belly syndrome adds weight to the unifying theory of the embryogenesis of gastroschisis and exomphalos.

Abnormalities, Multiple↗
PubMed1987

Care of disabled people in the community.

The initiatives raised by the International Year of Disabled Persons led to an understanding that the community may well be the best place to help disabled people. It is important to ensure that any major switch of resources from institutional to community care should be properly appraised, not just on cost-effectiveness grounds but also on the needs of the disabled persons themselves. Apart from the traditional medical input there is an imperative need to involve other professional and informal helpers to ensure the best possible outcome.

Community Health Services↗
PubMed1987

Changes in serum lipoproteins and high-density lipoprotein composition during isotretinoin therapy.

Oral isotretinoin has been reported to increase serum total triglycerides (TG), cholesterol (TC), phospholipids (TPL), apoprotein B (apo B), and to reduce high-density lipoprotein cholesterol (HDL-C). To investigate the effects of isotretinoin on HDL, we measured HDL-C, HDL phospholipids (HDL-PL), apoprotein A1 (apo A-1), and HDL-C subfractions (HDL2-C and HDL3-C) in 24 healthy, male patients receiving a 16-week course of isotretinoin (1.0 mg/kg/day) for treatment of severe acne vulgaris. Patients were placed on a constant diet and fasting lipid parameters were measured every 4 weeks. Analysis of the data from the 20 patients who completed the study confirmed the reported increase in TG, TC, LDL-C, apo B, and LDL-C/HDL-C (all p less than 0.01) observed during isotretinoin therapy. Reduction occurred in HDL-C (p less than 0.05) and HDL2-C (p less than 0.01) while HDL3-C remained unchanged, indicating that the effect of isotretinoin is on the HDL2-C subfraction. Apo A-1 and HDL-PL did not change significantly, suggesting that the reduction in HDL-C represents cholesterol depletion of the HDL particle rather than a reduction in HDL mass. After discontinuing isotretinoin, serum lipid parameters returned to baseline levels.

Acne Vulgaris↗
PubMed1986

Auxin-regulated gene expression.

During the 1960s a wide range of studies provided an information base that led to the suggestion that auxin-regulated cell processes--especially cell elongation--may be mediated by auxin-regulated gene expression. Indirect evidence from our work, based on the influence of inhibitors of RNA synthesis (e.g. actinomycin D) and of protein synthesis (e.g. cycloheximide) on auxin-induced cell elongation, coupled with correlations of the influence of auxin on RNA synthesis and cell elongation, provided the basis for this suggestion. With the availability of techniques for DNA-DNA and DNA-RNA hybridization, mRNA isolation-translation, in vitro 2D gel analysis of the translation products, and ultimately the cloning by recombinant DNA technologies of genomic DNA and copy DNAs (cDNAs) made to poly(A)+ mRNAs, we and others have provided direct evidence for the influence of auxin on the expression of a few genes (i.e. poly(A)+ RNA levels). Our laboratory has provided evidence for auxin's both down-regulating and up-regulating the level of a few poly(A)+ mRNAs out of a population of about 4 X 10(4) sequences that are not significantly affected by auxin. In our studies on auxin-regulated cell elongation, two cDNA clones (pJCW1 and pJCW2) were isolated which corresponded to poly(A)+ mRNAs that responded during growth transitions in a way consistent with a potential role of their protein products in cell elongation. These mRNAs are most abundant in the elongating zone of the soybean hypocotyl. Upon excision and incubation in the absence of auxin, these mRNAs deplete in concert with a decreasing rate of cell elongation. Addition of auxin to the medium results in both increased levels of these mRNAs and enhanced rates of cell elongation. These mRNAs do not deplete if auxin is added to the medium at the onset of excised incubation, and cell elongation rates remain high. We have isolated and sequenced genomic clones that are homologous to these cDNAs. Of the two genes sequenced, both genes are members of small multigene families. There are regions of high amino acid homology even though the nucleotide sequences are sufficiently different in these regions for cross-hybridization of the clones not to be observed. More recently others, especially Guilfoyle's laboratory, have shown that auxin selectively and rapidly influences the level of certain mRNAs and proteins. We have worked on other gene systems such as ribosomal proteins and possible cell wall proteins that are responsive to auxin; again the nature of regulation of expression of these genes is not known.(ABSTRACT TRUNCATED AT 400 WORDS)

DNA↗
PubMed1986

Schistosomiasis in expatriates returning to Britain from the tropics: a controlled study.

Clinical features in 173 white expatriates returning to Britain with the sole diagnosis of schistosomiasis were compared with those in non-infected control subjects, matched for age and sex, returning from similar endemic areas. Infection was, with one exception, acquired in Africa. Schistosoma mansoni was found in 135 patients, S haematobium in 29, and mixed infection in 9. 79% of patients with S haematobium had symptoms, compared with 47% of patients with S mansoni. Tiredness, headache, and gastrointestinal disturbance were no more frequent in symptomatic patients than in control subjects. In over 50% of patients with schistosomiasis the diagnosis was established from snips of rectal mucosa, and this raises the question of how best to look for infection in those who have been exposed. Urine examination and schistosomal serology appear to be the best screening methods; patients with haematuria or seropositivity should be investigated further.

Adolescent↗
PubMed1986

The effect of ischemia on canine carotid endothelial permeability.

The effect of ischemia on arterial endothelial permeability was assessed by surgically interrupting arterial blood flow for 45 min in the left carotid artery of 12 foxhounds. The right carotid artery served as control. Twenty-four hours before sacrificing the animals at 1 day, 1 week, 1 month, and 3 months postoperatively. Evans blue dye (1.5 ml/kg) was administered intravenously. Carotid arteries were harvested, opened, and scanned with a reflectometer to measure Evans blue dye uptake, and scanning electron microscopy was performed on a section of tissue from each harvested vessel. A statistically significant increase in permeability of the ischemic vessel occurred at 1 day (79 +/- 42% (SD], 1 week (186 +/- 75%), and 1 month (229 +/- 125%), but was not present at 3 months (7 +/- 8%) postinjury. Scanning electron microscopic examination of all specimens was essentially normal. This study demonstrates that arterial endothelium has increased permeability at 1 month following a brief ischemic period. What effect this ischemia-induced endothelial dysfunction will have on lipid uptake by the arterial wall will be the subject of future study.

Animals↗
PubMed1986

Duodenal duplication--3 new cases.

Duplications can occur anywhere in the alimentary tract from mouth to anus. There may be multiple duplications in about 15% of cases. The most common site is in the distal ileum, in over 50% of cases. Duodenal duplications are rare, and occur in only 5-10% of the total in recent reviews (3, 5, 7). Three cases of this very uncommon abnormality are reported.

Child, Preschool↗
PubMed1986

Kidney function in rats with corticomedullary nephrocalcinosis: effects of alterations in dietary calcium and magnesium.

Single-nephron and whole-kidney function were studied in female rats with corticomedullary nephrocalcinosis, and in animals where the lesion had been prevented either by a dietary magnesium supplement or by using a diet with a calcium:phosphorus ratio in excess of 1. At the single-nephron level, rats with nephrocalcinosis had prolonged tubular fluid transit times. Proximal transit time was 19.42 +/- 1.98 (mean +/- S.E. of mean) vs. 11.58 +/- 0.19 s for controls; distal transit time was 62.64 +/- 9.16 vs. 31.50 +/- 1.03 s for controls. Although single-nephron function is altered in nephrocalcinosis, data obtained from rats in metabolism cages indicate that whole-kidney function is largely unaffected by the lesion.

Animals↗
PubMed1986

Homology of cryptic plasmid of Neisseria gonorrhoeae with plasmids from Neisseria meningitidis and Neisseria lactamica.

DNA probe hybridisation was used to examine the relation between the cryptic plasmid from Neisseria gonorrhoeae and plasmids carried by pharyngeal isolates of Neisseria meningitidis and Neisseria lactamica. The complete gonococcal cryptic plasmid and HinfI derived digestion fragments subcloned into Escherichia coli were used to probe Southern blots of plasmid extracts. Homology was found to a plasmid of approximate molecular weight 4.5 kilobase pairs (Kb) but not to plasmids of less than 3.2 Kb or 6.5 Kb. Eleven of 16 strains of N meningitidis and two of six strains of N lactamica carried plasmids that showed strong hybridisation with the 4.2 Kb gonococcal plasmid. Hybridisation of plasmids from non-gonococcal species of neisseria with the gonococcal cryptic plasmid indicates that caution should be taken when using the cryptic plasmid as a diagnostic probe for gonorrhoea.

DNA, Bacterial↗