Search PubMed⌕ Search

Biomedical subjects

D Walker

Publications and source records attributed to D Walker.

At least 361 records · Page 20Linked to original sources
PubMed1983

[Role of recessive lethal genes in spontaneous embryonal lethality in random-bred rat and mouse populations in Cuba].

Spontaneous embryonic lethality and the recessive lethal gene frequency in the gene pool of noninbred mice and rats of the bioteria of the National Research Center of the Cuba Republic Academy of Sciences were investigated. It was established that the level of spontaneous embryonic lethality among mice increased greatly as compared to that in 1977 and was 40% (versus 20% in 1977). Of this number, 30% falls within the postimplantation period. In noninbred rats, these values constituted 21.4 and 8.1%, respectively. High embryonic lethality among noninbred mice may be determined by genetic causes and the influence of ecological factors. The frequency of recessive lethals among noninbred mice was 28%, that among rats 20.8%. It is characteristic that in both categories, recessive lethals became apparent only in the postimplantation period of embryogenesis.

Animals↗
PubMed1982

The Pietermaritzburg craniofacial unit.

The Pietermaritzburg Craniofacial Unit was established in 1976, and since its inception 150 patients with major skull and facial deformities have been referred there from centres throughout South Africa. Fifty craniofacial operations have been performed by the surgeons of the Unit, who form only a part of a team of 16 members from many branches of the medical, dental and allied professions. Craniofacial surgery is defined and reasons are presented for limiting the number of such highly specialized units.

Face↗
PubMed1982

Observations on the phosphate status and intracellular pH of intact cells, protoplasts and chloroplasts from photosynthetic tissue using phosphorus-31 nuclear magnetic resonance.

Individual pools of intracellular inorganic phosphate (Pi) can be observed in the dark in intact cells, protoplasts and chloroplasts from photosynthetic tissue by using 31P nuclear magnetic resonance (n.m.r.). Estimates for the pH of vacuolar and extravacuolar compartments are reported although it is shown that intracellular pH is determined by the pH of the suspending medium. Mannose treatment of asparagus (Asparagus officinalis) cells and spinach (Spinacia oleracea) protoplasts results in the inhibition of photosynthesis. The mechanism of mannose phosphate sequestration of free Pi is supported by the 31P n.m.r. spectra of mannose-treated tissue. There is a fundamental difference in 31 P n.m.r. spectra of mannose-treated spinach protoplasts and asparagus cells, reflecting a difference in the availability of vacuolar Pi for cellular metabolism in these species. The 31P n.m.r. spectrum of intact spinach chloroplasts is reported.

Chloroplasts↗
PubMed1982

A controlled comparison of two treatments for nocturnal enuresis.

This study assessed change in the frequency of primary nocturnal enuresis as produced by either behavioral conditioning with a urine alarm, pharmacotherapy with imipramine hydrochloride, or assignment to a clinical waiting list. The study also investigated the effect of treatment method and outcome on subjects' level of emotional and behavioral adjustment. An attempt was made to identify pretreatment predictors of treatment outcome and premature withdrawal from the treatment program. The results indicated a significantly more effective outcome for the conditioning approach. Comparison of pre- and post-treatment measures of adjustment provided insufficient evidence to support the hypotheses that either change in the frequency of nighttime wetting or the method of treatment received would influence the subject's level of emotional and behavioral adjustment. The enuresis tolerance scale was found to be a highly significant predictor of early termination from conditioning treatment.

Adolescent↗
PubMed1981

Behavioral and environmental characteristics of treated and untreated enuretic children and matched nonenuretic controls.

This correlational study investigated possible behavioral, parental, and environmental differences in enuretic children who were either receiving or not receiving treatment for bed-wetting. The subjects wer 5- to 12-year-old children who were nocturnally incontinent at least once a week and physically normal in all other respects. Seventeen of these youngsters were receiving pharmacologic treatment for enuresis (clinical enuretic group) and 20 were not (nonclinical enuretic group). Clinical enuretic children were older and wet more frequently than youngsters whose parents had not sought treatment for this problem. Their fathers more often held blue-collar jobs and their mothers were more intolerant of enuresis than were parents of the nonclinical enuretic sample. These two groups did not differ in number and type of child behavior problems, number of life-stress events, age toilet training commenced, or parental child-rearing practices employed. However, enuretic youngsters displayed more conduct problems and immature behavior than their nonenuretic counterparts. Mothers of enuretic youngsters applied more rule-oriented child-rearing practices than mothers of nonenuretic controls. There were no differences between the enuretic and nonenuretic groups in number of early-life stressful events or the age at which toilet training commenced.

Age Factors↗
PubMed1981

Abnormalities of neutrophil function do not cause the migration defect in Crohn's disease.

Skin window tests were performed on 60 patients with Crohn's disease, 20 with ulcerative colitis, 16 with peptic ulceration, and 40 healthy controls. The numbers of neutrophils that migrated into the skin window chambers were significantly lower in patients with Crohn's disease. This abnormality was unrelated to the activity of the disease, site of involvement, or treatment. No significant abnormalities were found in the patients with other diseases of the gastrointestinal tract. The abnormality of neutrophil migration in the Crohn's patients does not seem to be due to a cellular defect, as neutrophils from patients with Crohn's disease migrate and phagocytose normally in vitro. Sera from patients with Crohn's disease did not inhibit cell migration or contain inhibitors of chemotaxis. The addition of serum that had been activated with zymosan to the chamber enhanced the emigration of neutrophils from the skin of patients with Crohn's disease. These results suggest that the depression of neutrophil migration into skin windows that is normally observed in Crohn's disease is due to a deficient local inflammatory response. This defective inflammatory response in Crohn's disease and the consequent delay in the accumulation of neutrophils could explain granuloma formation, the high recurrence rate after surgery, and the clinical course of exacerbations and remissions.

Adult↗
PubMed1981

Traumatic left ventricular aneurysm in an 8-year-old child.

An asymptomatic 8-year-old boy was found to have a left ventricular aneurysm and a ventricular septal defect 14 months after a road traffic accident. At operation a large, thin-walled, clot-filled aneurysm was removed and the septal defect repaired.

Child↗
PubMed1981

Hypertension in a pediatric and adolescent population following kidney transplantation.

The post-renal transplant courses of 53 children and adolescents were evaluated for the prevalence and the etiology of hypertension. The blood pressures were averaged over specific time periods following transplantation and converted to percentile ranks according to standards for age. The number of antihypertensives employed to control blood pressure was assessed. Factors such as sex, obesity, race, donor source, antigen match, steroid administration, rejection, recurrent glomerulonephritis, pre-transplant nephrectomy, renal function and proteinuria were assessed as to their importance in producing hypertension or normotension in the post-transplant period. The average blood pressure was well within acceptable range shortly after transplantation. The patients requiring antihypertensives to control blood pressure dropped by two years post transplant. Chronic rejection was by far the most important factor influencing average blood pressure and the need to employ antihypertensives. Alternate-day prednisone and good graft function were important in establishing the normotensive state.

Adolescent↗