Biomedical subjects

Carl Lombard

Publications and source records attributed to Carl Lombard.

23 records · Page 2Linked to original sources

PubMed2003

Monitoring technologist reading skills in a sperm morphology quality control program.

OBJECTIVE: The value of sperm morphology as a predictor of a man's fertilizing potential has often been challenged because of different classification systems used to distinguish between normal and abnormal spermatozoa. The study aimed to monitor the reading skills of 53 laboratory technologists who are enrolled in a continuous quality control program for sperm morphology assessment. DESIGN: Prospective analytical study. SETTINGS: Academic hospital and academic institution setting. PATIENT(S): Sperm samples from the sperm donor program and andrology technicians from sub-Saharan Africa. INTERVENTION(S): Papanicolaou-stained sperm slides were prepared and shipped on a quarterly basis to participating laboratories. Papanicolaou-prestained sperm morphology slides were used as test material for 21 months. MAIN OUTCOME MEASURE(S): Percentage normal spermatozoa.A new statistical model was developed to record reading skills of the participating technicians. Reading skills were classified as marginal (5.7% of cases), good (11.3% of cases), and excellent (83% of cases). RESULT(S): Participants maintained their morphological reading skills and agreed with the reference laboratory by not exceeding a SD limit of 0.2 to set stringent standards for the program. CONCLUSION(S): Technician proficiency can be monitored using the results of a quality control program. A continuous quality control program can be initiated only after intensive training, because baseline values at the onset of the quality control program serves as an internal reference value.

Clinical Competence↗

PubMed2003

Substance use by adolescents in Cape Town: prevalence and correlates.

PURPOSE: The work reported in this paper was supported by grants from the World Health Organisation Programme on Substance Abuse, the United Nations Development Programme, the South African Medical Research Council, and the Medical Faculty Research Committee of the University of Cape Town.To document the prevalence rates for use of cigarettes, alcohol, and cannabis among high school students in Cape Town, and to investigate whether use of these substances is associated with a set of hypothesized psychosocial correlates. METHODS: A multistage sampling procedure produced a sample of 2930 students in grades 8 and 11 at 39 high schools in Cape Town, who completed a self-administered questionnaire. The questionnaire contained items about whether the students had used various substances and that addressed the potential correlates of interest. We calculated prevalence rates with 95% confidence intervals and constructed a set of generalized estimating equations of use in the past month of cigarettes, alcohol, or cannabis on the hypothesized correlates. RESULTS: The prevalence rates for previous month (recent) use of cigarettes, alcohol, and cannabis were 27%, 31%, and 7%, respectively. Rates were low for black females. Recent use of each of the substances was significantly associated with the number of days absent and the number of years lived in a city. Repeating a grade was significantly associated with previous month use of cigarettes and alcohol by colored (derived from Asian, European, and African ancestry) students and alcohol use by black grade 8 students (race classifications "colored" and "black" are as defined by the repealed population Registration Act of 1950). Not being raised by both parents was significantly associated with cigarette smoking by black and colored students, alcohol use by colored students, and cannabis use by female students. It was inversely associated with cigarette use by black students. CONCLUSIONS: It is necessary to identify the factors that protect black female adolescents from substance use. It is important to address demographic factors such as race classification and gender analytically if one is to avoid obscuring differences among groups.

Adolescent↗

PubMed2003

Sexual behaviour of Cape Town high-school students.

OBJECTIVES: To document prevalence rates for selected aspects of sexual behaviour among Cape Town high-school students and to conduct a survival analysis of age at first intercourse. DESIGN: Cross-sectional survey. SETTING: State high schools in Cape Town. SUBJECTS: A multistage cluster sample of 2,740 grade 8 and 11 students at 39 schools. OUTCOME MEASURES: Ever having had sexual intercourse; for those who had, age at first intercourse, number of partners during the previous 12 months, time since last intercourse; and, at last intercourse, whether the partner had been known for more than 7 days, whether any method was used to prevent pregnancy or disease, and (if so) what was used. RESULTS: Overall, 29.9% had participated in sexual intercourse, with a higher proportion among males and those in grade 11. By the age of 14 years, 23.4% of males and 5.5% of females had participated in sexual intercourse. By the age of 19 years, these proportions were 71.8% and 58.2% respectively. The median time since last intercourse was 4 weeks, the median number of partners in the past year was 1, and 78.4% had known their most recent partner for more than 7 days. At their last coital episode, 65.4% had used contraception, and the most common methods were condoms and injectable steroids, which were used by 67.7% and 43.2% respectively. CONCLUSIONS: The proportion of sexually active students has increased since 1990. Intervention programmes should commence in primary school. Large numbers of students are at risk for pregnancy and sexually transmitted infections.

Adolescent↗

PubMed2002

A systematic review of strategies for partner notification for sexually transmitted diseases, including HIV/AIDS.

This review compares the effects of various sexually transmitted disease (STD) partner-notification strategies. Using review methods endorsed by the Cochrane Collaboration, it updates previous reviews, and addresses some of their methodological limitations. It includes 11 randomized controlled trials (RCTs) comparing two or more strategies, including 8014 participants. Only two trials were conducted in developing countries, and only two trials were conducted among HIV-positive patients. The review found moderately strong evidence that: (1) provider referral alone, or the choice between patient and provider referral, when compared with patient referral among patients with HIV or any STD, increases the rate of partners presenting for medical evaluation; (2) contract referral, when compared with patient referral among patients with gonorrhoea, results in more partners presenting for medical evaluation; (3) verbal, nurse-given health education together with patient-centred counselling by lay workers, when compared with standard care among patients with any STD, results in small increases in the rate of partners treated. The review concludes that there is a need for evaluations of interventions combining provider training and patient education, for evaluations conducted in developing countries, and for the measurement of potential harmful effects.

Contact Tracing↗

PubMed2002

Reduction of the rate of false-positive cultures of Mycobacterium tuberculosis in a laboratory with a high culture positivity rate.

Our laboratory, engaged in a prospective study of adult pulmonary tuberculosis, processed on average 1186 sputum samples per year for the detection of Mycobacterium tuberculosis (M. tuberculosis). Approximately 55% of all sputum samples were culture-positive. The study protocol required that all patients had their M. tuberculosis isolates DNA fingerprinted at diagnosis, and at subsequent time points if the patients either failed treatment or presented again with tuberculosis. Over a 22-month period, there were 14 apparent treatment failures from 109 patients who had completed 6 months of therapy. Only two of these were true treatment failures, while the other 12 had DNA fingerprints that were different from those obtained at diagnosis. It was concluded that these 12 cultures represented episodes of laboratory cross-contamination. Retrospective DNA fingerprinting of patient isolates was done so that each patient had at least two independent isolates fingerprinted. This survey revealed that 7.3% of DNA fingerprints were discordant. False-positive cultures with discordant DNA fingerprints generally arose late in chemotherapy and the isolates were usually co-processed with other strongly smear-positive sputum samples. Simple modifications of laboratory procedures were made, and over a following 10.5-month period the false-positive rate was reduced to 2.1%. These modifications did not increase the workload or the cost of processing samples and can thus be used successfully by any laboratory, and particularly by those in resource-poor settings.

Adult↗