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Biomedical subjects

N Cameron

Publications and source records attributed to N Cameron.

At least 37 records · Page 2Linked to original sources
PubMed1994

Longitudinal analysis of adolescent growth in height, fatness, and fat patterning in rural South African black children.

Adolescent growth in height, fatness, and fat patterning was investigated in a sample of 79 rural South African black children studied longitudinally from 6-18 years. Data were analyzed relative to peak height velocity (PHV) to identify the phenomenon of "compensatory" growth in height during adolescence and to describe changes in fatness and fat patterning. Compensatory growth following PHV was clearly observed relative to NHANES data for African-Americans in that Z-scores for height at the start of the adolescent growth spurt were greater than those at the end of the spurt. Statistically significant differences in fatness and centralization between males and females did not occur until about 2 years after PHV was attained. Centralization of fat occurred in both sexes but more so in males. The lack of centralization in females was due to relatively greater triceps skinfold velocities. The rapid gain in post-PHV fatness in females may represent a physiological adaptation to an energetically sub-optimal environment, buffering the energetic costs of reproduction.

Adipose Tissue↗
PubMed1993

Assessment of growth and maturation during adolescence.

Clinical techniques currently used to assess adolescent growth and maturation are critically assessed with regard to anthropometric dimensions, measurement reliability, maturity indicators, and growth standards. While anthropometric measurements are virtually standardized throughout the world, a choice of techniques is available for the assessment of skeletal maturity, dental maturity and secondary sexual development. In addition, a variety of charts of international and national reference data are available for the comparison of individuals and groups. These assessment and comparison techniques are contrasted and compared to arrive at a scientifically appropriate set of recommendations for the clinical assessment of growth and maturity during adolescence.

Adolescent↗
PubMed1993

The growth of South African rural black children.

The growth status of two samples of South African rural black children, from Ubombo, KwaZulu, and Vaalwater, northern Transvaal, was compared with that of samples of American black children and three other rural sub-Saharan groups. All the sub-Saharan black children were shorter, lighter and had less subcutaneous fat than the American children. Their growth curves demonstrated the well-recognised pattern of deviation from American means before adolescence so that, by the start of adolescence, approximately 50% of the children were below the 10th centile of American norms. Adolescence in all groups is delayed and the magnitude of peak velocity reduced. The adolescent growth spurt appears, however, to be extended along the time base so that pre- and post-peak velocities are raised; this leads to apparent catch-up growth in the late teenage years. While the Vaalwater sample demonstrated growth patterns very similar to those of other rural sub-Saharan black groups, the Ubombo children were consistently taller and heavier than all the others. These data are discussed in relation to the need for national norms that reflect the growth status of black South African children.

Adolescent↗
PubMed1991

Missed opportunities for measles immunisation in selected western Cape hospitals.

Measles is still a major cause of childhood mortality and morbidity in South Africa. The World Health Organisation (WHO) has recently recommended that greater attention be paid to opportunities for immunisation in the curative sector. This study quantified the extent of missed opportunities for measles immunisation in children attending primary, secondary and tertiary level curative hospitals in the western Cape. Exit interviews of 1,068 carers of children aged between 6 and 59 months inclusive showed that 2.4-40.7% of carers had been requested to produce a Road-to-Health card, and that 4.8-43.1% of carers had a card available. The proportion of children with documented evidence of measles immunisation available ranged from 4.8% to 40.0% between facilities. The study demonstrated that a considerable number of potential opportunities to immunise children against measles are currently being missed in children attending hospitals and day hospitals in the western Cape. The study documents the effect of a fragmented approach to health care, and indicates a need for rapid integration of preventive and curative components of health care into a metropolitan-based primary health care service.

Child, Hospitalized↗
PubMed1991

'Birth to Ten'--pilot studies to test the feasibility of a birth cohort study investigating the effects of urbanisation in South Africa.

'Birth to Ten' is a birth cohort study currently being conducted in the Johannesburg-Soweto area. This paper describes the various pilot studies that were undertaken to investigate the feasibility of a cohort study in an urban area. These studies were designed to determine the monthly birth rate, the timing, frequency and duration of maternal antenatal visits, the timing and frequency of visits to well-baby clinics and the accuracy and reliability of routinely collected growth data. In addition, a birth data collection form was tested to ascertain the appropriateness of its use in clinics within the study area.

Birth Rate↗
PubMed1991

Birth to ten: child health in South Africa in the 1990s. Rationale and methods of a birth cohort study.

Birth to Ten is a longitudinal birth cohort study which began in April 1990 in the Johannesburg/Soweto area of Transvaal, South Africa. In this paper, the reason for the initiation of the study and its location in the current sociopolitical context is discussed. The health status of South Africa children in terms of infant mortality, morbidity (notifiable diseases) and nutritional status is described and mention is made of measures of psychological health and the importance of environmental pollution on health. The existing health service infrastructure in the study area is described and the fragmentation of health services between races, between preventive and curative services and on a geographical basis is highlighted. The study objectives, design, population, inclusion and exclusion criteria, methods of measurement and logistics are described.

Child↗
PubMed1990

The start of breast development and age at menarche in South African black females.

Age at the start of breast development and at menarche are important maturity indicators in adolescent females. Breast development is usually the first event of puberty and menarche virtually the last. Irregularities in the age of the subject at their appearance can denote a lack of synchronisation between pubertal events, which, in turn, may indicate hormonal or psychosocial disturbance. Data are presented on the age of occurrence of breast development, according to Tanner's criteria, and age at menarche for urban and rural South African black females. In addition published reports are reviewed to determine whether there is a pattern of change in these ages. Breast development seems to be fairly stable, occurring in girls between the ages of 10.5 years and 11.5 years. Age at menarche appears to have decreased over the last 40 years in children from both urban and rural environments. Girls from rural areas have a delay of about 1.5 years in both pubertal events.

Adolescent↗
PubMed1988

A critical assessment of the width coefficient, K, as an indicator of nutritional status.

The width coefficient, K, was assessed critically to examine its underlying assumptions, its relationship to absolute dimensions of body size, and its ability to identify children classified as malnourished by internationally accepted criteria. The scientific integrity of the formula to calculate K depended on the assumption that the body could be viewed as a cylinder with a density of 1.0 g/ml. The empirical testing of the former assumption showed that the body could not be viewed as a cylinder and papers describing body density suggest that age and sex dependency militate against the acceptance of an age- and sex-independent value of 1.0 g/ml. As an indicator of nutritional status K performed well in that it identified children below 75% of weight for age, but it could only identify 47% of children below 90% weight for height. The relative complexity of its calculation and interpretation militate against the use of K as an indicator of malnutrition for the general health worker, but its ability to identify moderately malnourished children by weight for age gives it credibility in the absence of an age assessment.

Black or African American↗
PubMed1988

Fast to slow phenotypic changes in rabbit muscle can be induced without increases in neural activity.

Immobilization of rabbit tibialis anterior (fast) muscle in a lengthened position for 5 weeks led to a fivefold increase in the number of slow oxidative fibres. Unlike the situation in other models of phenotypic change in adult muscle, the increased expression of slow phenotype was not associated with an increase in the level of electrical activation, as monitored in the stretched muscles by chronic telemetric electromyography.

Animals↗
PubMed1988

Recovery from immobilization-induced atrophy of rabbit soleus muscles can be accelerated by chronic low-frequency stimulation.

Immobilization of rabbit soleus muscles with an ankle joint angle of 90 degrees led to gross degeneration after 2 weeks. Natural recovery in the subsequent 2 weeks had little effect on the mean area of soleus fibres, although there were signs of regeneration. However chronic low-frequency activation of soleus muscles by nerve stimulation greatly accelerated recovery, producing muscle fibres of normal areas and with characteristics of maturity.

Animals↗