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Biomedical subjects

C A van der Merwe

Publications and source records attributed to C A van der Merwe.

At least 55 records · Page 3Linked to original sources
PubMed1986

Prognostic factors in patients with small-cell carcinoma of the lung.

Fifty-two patients with histologically confirmed small-cell carcinoma of the lung, 15 with disease localized to one hemithorax and 37 with extensive metastases, were studied. Only patients whose general condition was considered good enough to tolerate intensive combination chemotherapy were included in this study. The median survival time of these patients was 33 weeks (range 7-192 weeks) with a mean survival time of 43 weeks. Patients who responded with objective tumour improvement within 6 weeks had a median survival time of 39 weeks. Those showing disease stabilization at 6 weeks had a median survival time of 35 weeks while those having disease progression at this time had a median survival of 22 weeks. Patients without liver involvement and a normal serum albumin level at the start of treatment had statistically superior survival times.

Adult↗
PubMed1986

[The influence of air pollution on health in the Sasolburg area].

Excessive air pollution by industries in the Sasolburg area is suspected of affecting the residents' health in general and the respiratory system in particular. In the present investigation children from primary schools at Sasolburg were compared with those from the neighbouring rural towns of Parys, Heilbron and Frankfort, all with negligible air pollution levels. Although no important differences in the incidence of respiratory illness were evident from the questionnaire administered, there was a significant difference in the forced expiratory volume in 1 second (FEV1) of boys in the two groups. In addition there was an observed trend for all lung functions to be slightly worse in the study area. This trend seemed to be unaffected by the smoking habits of families but the social class from which the children originated might have been a contributory factor.

Air Pollution↗
PubMed1986

Comparison between atracurium and alcuronium for muscle relaxation during laparoscopy.

Atracurium 0.3 mg/kg was compared with alcuronium 0.25 mg/kg as the sole muscle relaxant for tracheal intubation and abdominal relaxation for gynaecological laparoscopy in 46 patients during nitrous oxide, oxygen and halothane anaesthesia. Speed of onset, intubation conditions, effect on blood pressure and pulse rate, and ease of reversal were compared. Alcuronium had a significantly faster onset of action than atracurium; intubation conditions were adequate and abdominal relaxation was satisfactory for both drugs. The effect of atracurium was readily reversible within 10 minutes; in contrast alcuronium was significantly more resistant and mean recovery time was 28.03 minutes. Although alcuronium provided good muscle relaxation, it is not suitable for short procedures because of difficulty in reversing its action. Atracurium allowed earlier and more complete reversal of neuromuscular block.

Adult↗
PubMed1986

A comprehensive investigation of immunity to poliomyelitis in a developing country.

A comprehensive nationwide surveillance program of serologic immunity of two-year-old black children, combined with evaluation of vaccine quality and distribution, was carried out in South Africa during 1983-1984. Sera were randomly collected from urban and rural groups and cluster samples collected from the semi-urban group. The sample represented 0.23% of the total target population. Satisfactory levels of immunity were found in the urban (80%) and semi-urban (71%) groups but a disquietingly low level was found for the rural group (59%). Individual districts in the rural group could be singled out for directed cluster sampling at a later stage. History and documentation of immunization corresponded well to serologic findings and revealed also a fairly substantial level of natural immunization among individuals who, on history, had received no vaccine. Some 95% of random samples of vaccine recalled from the field showed satisfactory levels of potency. An immunity surveillance program such as this is ideally suited and highly cost-effective for developing countries with incomplete immunization to prevent large-scale buildup of immunity deficit. The technique, however, is too insensitive to detect localized community immunity defects.

Antibodies, Viral↗
PubMed1986

Subclinical impairment of colour vision in patients receiving ethambutol.

Colour discrimination was assessed by means of the Farnsworth-Munsell 100-Hue test in 54 patients being treated for tuberculosis with ethambutol and 50 patients who were treated for tuberculosis by drugs other than ethambutol. The ethambutol group showed significantly more errors than controls along the deuteran axis. The sub-group of ethambutol treated patients who had been taking the drug for more than 2 months showed significantly more errors along the tritan axis. It is concluded that subclinical colour discrimination impairment is relatively common in patients receiving ethambutol and that a deuteran type of defect is an early and a tritan type of defect is a later manifestation of ethambutol toxicity.

Adult↗
PubMed1986

Immittance screening in black preschool children attending day-care centres.

Immittance screening was performed on 736 black children between the age of 2 and 6 years attending four day-care centres. It was found that 14.9% of these children failed the immittance screening. Problems encountered when attempting to apply the available standard immittance screening pass/fail criteria to a specific black race group are discussed.

Acoustic Impedance Tests↗
PubMed1985

A new multiple sclerosis epidemic? A pilot survey.

There may be an increasing incidence of multiple sclerosis in South Africa. All newly-diagnosed white Afrikaans-speaking patients from the Pretoria area were examined over a 12-month period and 5 new cases were diagnosed. This is a highly significant rise over the expected 0,2/100 000/year (P less than 0,001).

Humans↗
PubMed1985

Prevalence of hepatitis virus and some arbovirus infections in Kavango, northern SWA/Namibia.

A survey of the frequency of hepatitis B markers in 258 subjects from Kavango, northern South West Africa/Namibia, was undertaken during February - May 1983. The hepatitis B surface antigen and hepatitis B e antigen carrier rates were 13,6% and 2,7% respectively. Only 1,9% of the subjects were negative for all the markers tested, indicating that infection had been present at some stage in 98,1% of the sample. No known transmission method of the virus seems to fit this high exposure rate. The possibility that arthropod transmission of the virus may play a role in the epidemiology of the disease in Kavango is being investigated. All subjects tested for antibodies to hepatitis A virus were found to give a positive result. Of the arboviruses tested for, West Nile virus was usually predominant and was probably responsible for most of the arbovirus infections. Antibodies to the Sindbis, Chikungunya, Germiston and Rift Valley fever viruses were also found.

Adolescent↗
PubMed1985

Delayed skin hypersensitivity as indicator of T-cell function in three population groups.

Immunological differences between a rural under-developed black population with a low incidence of rheumatoid arthritis, and living according to old traditional ways have been compared with an urban black and urban Caucasian population with a high incidence of the disease. A delayed skin hypersensitivity test for cell-mediated immunity with seven antigens and control was used. The rural group showed a statistically significant inhibition of cell-mediated immunity with 37% showing an anergic response. A matched Caucasian group showed a more marked response while an urban black group occupied an intermediate position. The 37% anergic response in our rural group was seen despite the fact that they were very healthy and their immune systems resisted multiple parasitic and infective onslaughts. From this data interpretation of an anergic response to multiple skin antigen tests in peoples from under-developed populations must be approached with great caution. Whether this altered cell-mediated immunity plays a role in the low incidence of rheumatoid arthritis in under-developed peoples is still speculative.

Arthritis, Rheumatoid↗
PubMed1984

Weight-for-height nutrition surveys in rural Kwazulu and Natal, July 1983.

South Africa experienced a severe drought in 1982/1983. In July 1983 certain rural communities were identified which had recorded the most severe drought. Children were selected at random from these areas and compared against controls with regard to their respective weights and heights. On the basis of the predetermined sample sizes employed, no significant difference between the groups could be demonstrated. When compared with certain urban children attending crèches in Pretoria, there was also no significant difference. It is concluded that in July 1983 no crisis as regards the prevalence of acute malnutrition in children aged 1-5 years existed in the communities tested.

Black or African American↗
PubMed1984

Classificatory reliability of the Carabelli trait in man.

Classificatory reliability of the Carabelli trait was evaluated using randomly-selected study models and 52 unbiased observers. Benzécri's correspondence analysis showed Dahlberg's classification to be the most confidently applied. Observers showed less confidence in the application of individual class boundaries described by Goose and Lee; the methods of Alvesalo and Shapiro were the least confidently applied. Pair-wise Yates' chi-square tests on differences in left and right counts for each of the above methods indicated a significantly higher degree of antimeric classificatory consistency for the Dahlberg method.

Classification↗
PubMed1984

The IgA immune system in epileptics on anticonvulsant therapy.

Disturbances in IgA have often been reported in white epileptics on anticonvulsant therapy. The clinical significance of these disorders is of interest as this aspect does not appear to have been sufficiently explored. In a previous study neither African nor Caucasian epileptics on treatment showed a deficiency of serum IgA. Since secretory IgA is the main defence factor in protecting mucosal surfaces, the object of the present study was simultaneously to determine serum and salivary IgA in suitable subjects and to monitor related clinical events. A similar elevation of salivary IgA level was found in Black and White epileptics on treatment. Clinical events were rare and were not related either to serum or secretory IgA concentrations. It is concluded that at present epileptics do not seem to require special immunological or clinical monitoring.

Epilepsy↗