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Biomedical subjects

A R Walker

Publications and source records attributed to A R Walker.

At least 235 records · Page 13Linked to original sources
PubMed1990

What causes appendicitis?

Appendicitis was rare in the past and still is in traditional Third World populations. It began to increase a century ago, peaked about 1950, and has now fallen to about half its previous incidence. As to causation, dietetically, it was contended that the increase was promoted primarily by an associated fall in dietary fiber intake. The recently advanced hygiene hypothesis considers the increase to have stemmed from improvements in hygiene, generally; these limited exposure to enteric infections and modified response to virus infections, thereby triggering appendicitis. Major uncertainties still prevail over the promotive and precipitating factors of the disease. It is doubtful whether individuals can take any action to avoid appendicitis.

Africa↗
PubMed1989

The effect of dose and line on immunisation of cattle with lymphoblastoid cells infected with Theileria annulata.

Thirty-one Friesian calves in Morocco susceptible to tropical theileriosis were protected against a lethal sporozoite challenge by prior infection with lymphoblastoid cell lines infected and transformed in vitro by a Moroccan stock of Theileria annulata. The challenge infection of cryopreserved sporozoites killed all four susceptible control calves within 20 days. Four schizont-infected cell cultures at Passage 3 were inoculated at four different doses, 10(8), 10(6), 10(4) and 10(2), into pairs of calves. The recipient animals showed great variation in severity of disease symptoms, which did not show a linear correlation with the cell dose inoculated. The most severe disease symptoms were recorded, prior to challenge, in the 10(2) cell dose recipients; one animal died of acute theileriosis and another had to be treated. One of the four cell lines used was more virulent than the other three. Two years after the completion of this experiment, immunised animals have shown normal productivity traits.

Animals↗
PubMed1989

Amblyomma variegatum ticks and the occurrence of bovine streptothricosis in Antigua.

The association between the occurrence of Amblyomma variegatum ticks and streptothricosis was studied on the Caribbean island of Antigua. The prevalence of streptothricosis was higher on animals having A. variegatum ticks compared to that of animals not infested with A. variegatum ticks. There was a steady increase in the prevalence of severe lesions as the level of infestation with adult A. variegatum ticks increased. However the distribution of skin lesions could not be related to the predilection feeding sites of adult A. variegatum ticks.

Abattoirs↗
PubMed1989

Growth of South African Indian schoolchildren in different social classes.

The height and weight of 4594 Indian schoolchildren aged 6 to 17 years, in Durban, South Africa, were measured at schools selected by inspectors as representative of upper, intermediate, and lower socio-economic populations. Significant superiority, anthropometrically, prevailed at all ages in upper compared with lower or poor-class children, but tended to lessen at 17 years. In the affluent group, in the age period studied the proportions under the 5th percentile of USA NCHS reference values were--concerning height-for-age 4.7% to 22.0% of boys and 5.0% to 20.7% of girls; and concerning weight-for-age, 20.3% to 45.0% of boys and 9.3% to 37.7% of girls. In the affluent group, at full growth at 17 years, means of height and weight were highly significantly lower, namely, roughly by 7cm and 10kg, compared with respective mean values given in USA reference values. Hence, in Indian schoolchildren a genetic factor, and not dietary inadequacy, appears primarily responsible for both slower post-pubertal growth and lower ultimate height attainment.

Adolescent↗
PubMed1989

Appendicitis in Soweto, South Africa: traditional healers and hospitalization.

Appendicitis is near absent in rural blacks in Africa, and even in urban areas it remains very uncommon. Since the disease is new, and, moreover, potentially dangerous, a study was made of the antecedent history of 97 patients with proven appendicitis. Information was acquired concerning visits, and treatments and history, of (1) 34 patients who went first to traditional healers, and (2) 63 patients who sought orthodox medical attention. Of healers' treatments, none was beneficial; patients were ultimately directed, or decided to go to the hospital. Throughout Africa, traditional healers are held in high esteem and very extensively patronized. Accordingly, in both rural and in urban areas, concerted endeavours must be made by health authorities to promote recognition by healers of those diseases, acute or malignant, for which patients should be told to seek immediate medical attention.

Adolescent↗
PubMed1989

Prevalence of gallstones in elderly black women in Soweto, Johannesburg, as assessed by ultrasound.

In Western populations, about a third of elderly women have gallstones, as assessed from ultrasonography. In South Africa, cholelithiasis is reported to be increasing in urban blacks. Their recent dietary changes include a rise in fat and a fall in dietary fiber intake. To assess the current situation, we have carried out ultrasonography studies on 100 urban black women, 55-85 yr old, with no clinical evidence of gastrointestinal disease, especially with reference to the biliary system. Ten patients (10%) were positive. There was no association with parity. Their body mass index (27.8 +/- 6.9) was significantly higher (P less than 0.05) than those who were negative (25.7 +/- 6.1). From dietary intake assessments, there were no significant differences between those positive and negative with respect to mean intakes of energy, protein, fat, carbohydrate, dietary fiber or sugar (p greater than 0.05). Continuing exposure to a western lifestyle would be expected to increase prevalences of gallstones.

Black or African American↗
PubMed1989

Low frequency of adverse sequelae of obesity in South African rural black women.

In a series of 210 black women aged 25-45 years in a village in Eastern Transvaal, South Africa, 40 (19.0%) were obese, having a Body Mass Index (kg/m2) of 30 or more. Mean triceps skinfold was 23.5 mm; in 10 (25%) it was 25 mm or more) Hypertension (greater than or equal to 160/95 mm Hg) was present in 3 women (7.5%), hyperglycaemia (greater than or equal to 7.8 mmol/l) in 1 (2.5%), hypercholesterolaemia (greater than or equal to 5.2 mmol/l) in 3 (7.5%), and hypertriglyceridaemia (greater than or equal to 1.8 mmol/l) in 3 (7.5%). Dietarily, mean intake of energy was 2260 kcals, protein 73 g (12.9% energy), fat 55 g (20.8% energy), and carbohydrate 369 g (65.3%). In this context, of low fat, low animal food intakes, together with high physical activity, one or more of the adverse sequelae enumerated were present in 5 women (12.5%). Accordingly, in 35 women (87.5%), their obesity could be regarded as "healthy" obesity.

Adult↗
PubMed1988

Influence of a habitual high egg intake on serum lipid levels in a rural coloured population.

The effect of a habitual high cholesterol intake on serum cholesterol and other lipid levels against the background of a moderate fat intake was investigated in 30 rural coloured volunteers (16 men, 14 women) working on an egg farm. Protein contributed approximately 11%, fat 31%, carbohydrate 58% (sucrose 21%) of energy intake. Daily cholesterol intake averaged 575 mg. In men, although not in women, cholesterol intake correlated negatively with serum cholesterol and low-density lipoprotein cholesterol levels, indicating that a high consumption of eggs in the study population did not prejudice lipid homeostasis. The population exhibited a high profile of coronary heart disease risk factors.

Cholesterol↗
PubMed1988

Colorectal cancer. Some aspects of epidemiology, risk factors, treatment, screening and survival.

In developed populations colorectal cancer, which after lung cancer is the commonest of cancers, accounts for up to 6% of all deaths. It occurs most frequently in populations in prosperous industrialised countries, save Japan, and is rare in Third-World populations pursuing a traditional lifestyle. Peak occurrence is in the 7th decade. Colon cancer affects the sexes equally, but males are much more prone to rectal cancer. The precise causation is uncertain. Risk factors include genetic or familial predisposition, inflammatory bowel disease, diet (especially high fat and low dietary fibre intakes), and possibly alcohol intake. Surgery remains the treatment of choice. Stage is by far the most important factor influencing prognosis. Major refinements in both surgical and therapeutic measures have had disappointingly little effect on survival time. Overall median mortality occurs in 1-1 1/2 years; only one-third to one-half of patients survive for 5 years. While effective screening for very early detection could increase survival time, this will result only from further education. Since little avoiding action is practicable, the outlook for patients will remain daunting until help is sought far earlier.

Adult↗