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Biomedical subjects

A R Walker

Publications and source records attributed to A R Walker.

At least 145 records · Page 8Linked to original sources
PubMed1995

HIV infections in children.

HIV infection in infants and children who acquire it early in life is quite different from HIV infection in adults. The immune deficiency that results occurs in an immunologically naive organism, resulting in a larger role for common pathogens in causing severe infections. The immune deficiency is superimposed on age-related changes in all parts of the immune system so that a CD4 count that would be comforting in an adult or older child is cause for concern in an infant. Manifestations of infection include susceptibility to common and opportunistic infection, but growth failure and neurocognitive delays are much more significant patterns of disease than in adults. Therapy is clearly effective in slowing progression of the disease and, in the case of treatment of the pregnant woman, capable of primarily preventing the infection. The emergency physician's role in the treatment of children with HIV infection includes early identification, management of infections and complications, and advocacy for children who are so often unable to advocate for themselves.

AIDS Dementia Complex↗
PubMed1995

Cancer outlook: an African perspective.

In all western populations, mortality rates from cancer are high and even increasing: moreover, incidence rates of some cancers are also rising. As to propitiousness of preventive factors, genetic, gender, and age are beyond alteration: much the same applies to certain protective factors, e.g. late menarche, teenage pregnancy, high parity, long lactation, and greater physical activity. Influential dietary factors, i.e. intakes of energy, fat and fibre, often do not lend themselves to major alteration. Although reductions in smoking have occurred, the practice remains widespread and the intake of alcohol remains high. In developing countries, such as Africa, life-style changes are occurring and the population is incurring all risk factors mentioned. Whereas cancer is relatively uncommon in rural dwellers in developing countries, it is increasing in the huge peri-urban and urban populations due to changes in diet and way of life. Although knowledge should enable us to halve cancer's burden, hopes for meaningful changes are meagre. Survival time can be lengthened by more effective screening, especially of the very susceptible, and by further advances in treatment. Since known risk factors account for only half or less of occurrences of cancer, further rises, or, hopefully, welcome falls, could conceivably occur in the future. We must continue to try to educate the public regarding cancer avoidance: compliance by even a small proportion of those at risk could benefit huge numbers.

Africa↗
PubMed1995

Changes in the anthropometric status of rural African under-fives during a decade of primary health care.

Protein energy malnutrition (PEM) is a major cause of hospital admissions and death in most impoverished Third World countries. In the Gelukspan Health Ward, in rural Western Transvaal, a primary health care (PHC) programme, based on the GOBI-FFF strategy, commenced in 1980. Community health surveys on African under-five children were regularly undertaken. In 1990, to assess improvements achieved, anthropometric and other data were obtained on a representative series of 926 children. Harvard standards were used prior to 1984, and American NCHS reference standards thereafter. Low weight-for-age fell from 28 to 19%, low height for age from 33 to 17%, and low weight-for-height from 5 to 1%. The percentage with low arm circumference was unaffected, 3 and 4%, respectively. The improvements described are believed to be due in part to the PHC programme. Greater definition of the causes and extent of improvements are needed to optimize the State's present desire to intensify PHC, especially in rural areas.

Anthropometry↗
PubMed1995

Is the lesser growth of African schoolchildren essentially prejudicial to their present and future health?

In African and other Third World countries, 20-50% of schoolchildren lie under the 5th centile of US National Center for Health Statistics (NCHS) growth reference standards for weight- and height-for-age. Such lesser growth, orthodoxly, categorizes those affected as malnourished, at greater risk of disease, of lesser intelligence, and in need of nutritional supplementation. Questions arising include: 'Are there limitations to the application of NCHS reference standards?' In African schoolchildren, is lesser growth attributable largely, or marginally, to insufficient food intake? How powerful are the non-dietary influencing factors? What are the associated disadvantages to health? Conversely, could lesser growth around puberty even be beneficial respecting possible lessening of subsequent risk of degenerative diseases? Discussion indicates that there are numerous complexities in the whole subject of anthropometry, malnutrition and its stigmata, and interventions, dietary and non-dietary, in the youth of poor populations. In view of the invariably low health funds available in Third World countries, only intervention measures of proven significance to pupils' health warrant implementation.

Africa↗
PubMed1994

Diet and cancer.

Explore the source record for details and available documents.

Africa↗
PubMed1994

Sugar consumption and dental caries: evidence from 90 countries.

An examination is made of data on dental caries amongst 12-year-old children and sugar consumption of the total population for 90 countries. For the whole data set, DMFT score tends to rise with sugar consumption. The linear relationship between the logarithm of DMFT and sugar is estimated to have a slope of 0.021 per kg/year per head of population (P < 0.0001), and accounts for 28% of the variation in DMFT. In contrast, when data from 29 industrialised nations are analysed separately, there is no evidence of a sugar-caries relationship; the slope of the linear regression line is estimated to be -0.013, not significantly different from zero. This latter result is in agreement with the considerable evidence of a lack of strong relationship between the amount of sugar consumed and caries occurrence in Western countries. These results suggest that, in addition to sugar, other factors, such as other aspects of diet, exposure to fluoride and genetic effects, must be taken into account when seeking to explain variations in caries prevalence, and when making recommendations for caries control.

Australia↗
PubMed1994

Evidence for a mounting sex pheromone in the brown ear tick Rhipicephalus appendiculatus, Neuman 1901 (Acari: Ixodidae).

The presence of a mounting sex pheromone was demonstrated on the surface of fed female Rhipicephalus appeniculatus. This pheromone, which is present on the female cuticle, allows the male to recognise the female. The pheromone was removed by cleaning the female in hexane, resulting in the loss of male mating behaviour in in vitro experiments. Male mating behaviour was resumed when extract made from fed female cuticle was replaced on cleaned females. When the extract was transferred to inanimate objects typical male mating behaviour was released. Preliminary chemical analyses indicated that the active component of the extract was contained in the sterol ester fraction of the extract.

Animals↗
PubMed1994

Effect of acaricide control of Amblyomma variegatum ticks on bovine dermatophilosis on nevis.

A sentinel group of 8 Bos taurus cattle was compared with similar cattle in a herd of 90 of which 21 were pastured with the sentinels. The sentinel group was not treated with acaricide whilst the rest of the cattle were treated weekly with the organophosphate acaricide ethion. Weekly counts of adult ticks and rankings of dermatophilosis were made on the sentinel herd. The remaining cattle were observed for the presence of ticks and dermatophilosis prior to the weekly treatment with acaricide. All sentinel cattle became infested with Amblyomma variegatum ticks and dermatophilosis developed on all. Rank correlations of tick numbers and dermatophilosis scores were between +0.34 and +0.98, varying with maturity of cattle and time during the trial. Incidence of dermatophilosis on the cattle treated with acaricide was very low. Tick numbers on the sentinel animals were compared to rainfall and temperature. It is concluded that acaricide is the best option for controlling bovine dermatophilosis in Nevis.

Actinomycetales Infections↗
PubMed1994

Maximal genetic potential for adult stature: is this aim desirable?

Current nutrition theory holds that maximization of human growth and stature is a desired anthropometric outcome. However, some evidence demonstrates that lower energy intakes may actually confer a degree of future protection against degenerative processes, particularly atherosclerosis and cancer.

Adult↗
PubMed1994

Lactation--how important is it?

In Africa, with poverty rising, and health care diminishing, a nutritional question is-what are the limits of successful physiological adaptation to low dietary intakes? In this review the practice of lactation is discussed, from both past and present viewpoints. Orthodox Recommended Allowances for lactation are scarcely ever met. Yet, through various adaptations, the huge majority of African and similarly placed mothers lactate successfully and produce milk of good quantity and quality. The benefits from supplements are discussed; broadly, results have been disappointing. Some good and adverse non-dietary practices are considered. Benefits for infant and mother from lactation, even for protracted periods, far exceed drawbacks.

Africa↗
PubMed1994

Causes of admissions of rural African patients to Murchison Hospital, Natal, South Africa.

An analysis has been made of causes of admission of black patients in 1991 to Murchison Hospital, Port Shepstone, Natal. Of 6675 total admissions, 6329 (95%) were classifiable. Of the latter, 1462 (23%) were aged 12 years and-younger, namely, 763 boys and 699 girls. Their chief causes of admission were pneumonia, gastroenteritis, trauma, acute glomerular nephritis, and malnutritional diseases. Of 4867 adults (73%), 1536 were males and 3331 females. Among men, chief causes were tuberculosis, congestive cardiac failure, hypertension and cerebral vascular accidents. Among women, apart from pregnancy, chief causes of admission were disorders of pregnancy, tuberculosis, congestive cardiac failure, pneumonia, diabetes, and hypertension. Of western diseases, 3.9% of adults were admitted for diabetes, and 2.8% for asthma. The general pattern of admissions is similar to that in other rural hospitals. The causes of admissions are discussed, regarding (1) public health improvements occurring, and (2) means of promoting further improvements by (a) community self-help, and (b) help from State health and other services.

Adult↗