'No difference v. not enough evidence'--calculating the power and beta error.
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Animals↗
Biomedical subjects
E Gouws
Publications and source records attributed to E Gouws.
Prevalence and transmission of HTLV-I infection in Natal/KwaZulu.
A community-based seroprevalence survey for human T-cell lymphotropic virus type I (HTLV-I) was undertaken in the Ngwelezane district of Natal/KwaZulu. A total of 1,018 individuals was interviewed for risk factors and had blood drawn for serological examination. To exclude antibody cross-reactivity between anti-HTLV-I and anti-HTLV-II all Western blot HTLV-I-positive samples were further subjected to a Select HTLV test. For comparison, anonymous HIV testing was done. The areas of residence of patients with myelopathy associated with HTLV-I were also ascertained. The seroprevalence of HTLV-I was 2.6% (95% confidence interval (CI) 1.62-3.58). An age-related rise in HTLV-I seropositivity from 1.3% in the 15-24-year age group to 6.1% in the over 55-year-old group was noted. There was no significant association between HTLV-I antibody positivity and marital status, occupation, history of blood transfusion, scarification, age at first sexual experience and number of sexual partners. Anti-HIV-1 antibody testing revealed a positivity of 3.5% (95% CI 2.4-4.68) and the relative risk for co-infection with both HTLV-I and HIV-1 in the 15-24-year group was 1.16 (95% CI 1.08-1.24). The study also identified the first HTLV-II-seropositive case in the Natal/KwaZulu region. Up to December 1991, 90 cases of HTLV-I-associated myelopathy/tropical spastic paraparesis were seen at the Neurology Unit, Wentworth Hospital. The patients came from all parts of Natal, from Pongola in the north to Transkei in the south. The Natal/KwaZulu region is, therefore, an endemic HTLV-I area.
Adolescent↗
Assessment of the residual efficacy of lambda-cyhalothrin. 2. A comparison with DDT for the intradomiciliary control of Anopheles arabiensis in South Africa.
There are several factors that support the need to assess the efficacy of potential alternative insecticides to DDT for malaria vector control. The objectives of this study were to evaluate the persistence and efficacy against Anopheles arabiensis of lambda-cyhalothrin used as an intradomiciliary insecticide in daub huts and to compare its efficacy in this regard to DDT. Exit trap catches showed the population of An. arabiensis was high during the months of January to March, with a peak in February. During all months, the number caught leaving lambda-cyhalothrin-sprayed huts was markedly less than the number from both control and DDT-sprayed huts. The percentage survival of bloodfed mosquitoes ranged from a low of 55% caught leaving the lambda-cyhalothrin-sprayed huts, to 82% of those caught leaving DDT-sprayed huts. The percentage of bloodfed mosquitoes caught leaving huts was high (> 60%). The survival of unfed mosquitoes was low, even from the control huts (43%).
Animals↗
Rapid administration of crystalloid preload does not decrease the incidence of hypotension after spinal anaesthesia for elective caesarean section.
Twenty parturients undergoing elective Caesarean section were allocated randomly to receive crystalloid preload 20 ml kg-1 over either 20 min or 10 min before spinal anaesthesia. Significant hypotension (systolic arterial pressure less than 100 mm Hg and less than 80% of baseline value) occurred in six of the 10 patients in the 20-min preload group and seven of 10 patients in the 10-min preload group (ns). Both groups had a significant (P less than 0.05) increase in central venous pressure during the preload period. The mean central venous pressure in the 10-min group was 11.9 mm Hg (range 6-19 mm Hg), which was significantly greater (P less than 0.05) than that in the 20-min group (mean 7.3 mm Hg, range 2-13 mm Hg). Three patients in the 10-min group had clinically unacceptable increases in central venous pressure. This study has demonstrated that rapid administration of crystalloid preload before spinal anaesthesia did not decrease the incidence or severity of hypotension, and questions the role of crystalloid preload.
Adult↗
Relative risk analysis of factors associated with difficult intubation in obstetric anesthesia.
Difficult tracheal intubation, often unexpected, has been identified as the commonest contributory factor to anesthetic-related maternal death. The ability to predict such cases preoperatively would be of great value. Preoperative airway assessment and potential risk factors for difficult tracheal intubation were recorded in 1,500 patients undergoing emergency and elective cesarean section under general anesthesia. Airway assessment using a modified Mallampati test recorded oropharyngeal structures visible upon maximal mouth opening. Potential risk factors documented were obesity; short neck; missing, protruding, or single maxillary incisors; receding mandible; facial edema; and swollen tongue. Subsequent to induction of anesthesia, the view at laryngoscopy and difficulty at intubation were graded. There was a significant (P less than 0.001) correlation between the oropharyngeal structures seen and both the veiw at laryngoscopy and difficulty at intubation. Univariate analysis demonstrated a significant association between difficult intubation and short neck (P less than 0.001), obesity (P less than 0.0001), missing maxillary incisors (P less than 0.02), protruding maxillary incisors (P less than 0.001), single maxillary incisor (P less than 0.0001), and receding mandible (P less than 0.003). Neither facial edema (P = 0.414) nor swollen tongue (P = 0.141) were found to be associated with difficult intubation. Multivariate analysis removed obesity and missing and single maxillary incisors as risk factors. Obesity was eliminated because of its strong association with short neck. The probability of experiencing a difficult intubation for various combinations of risk factors was determined.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
A comparative study of the use of epoprostenol and dihydralazine in severe hypertension in pregnancy.
OBJECTIVE: To compare the antihypertensive effects of epoprostenol sodium (prostacyclin) with that of dihydralazine in acute hypertensive crises of pregnancy. DESIGN: A prospective randomized study. A minimum of 20 patients per group was considered statistically acceptable (alpha = 0.05, power = 0.9). SETTING: A large urban tertiary hospital. SUBJECTS: Forty-seven pregnant patients with diastolic blood pressures of > 100 mmHg were studied. INTERVENTION: Lowering of high blood pressure with either dihydralazine (n = 25), the standard drug for this purpose, or epoprostenol (n = 22). MAIN OUTCOME MEASURE: A significant drop in high blood pressure was regarded as a fall of 15 mmHg diastolic and 30 mmHg systolic blood pressure. RESULTS: There were no statistically significant differences in the antihypertensive effects between the two treatment groups. Epoprostenol infusion caused less tachycardia; the mean pulse rate changed from 81.77 beats/min, before treatment to 88.36 at stabilization, compared with a change from 80.96 beats/min to 102.68 in the group treated with dihydralazine (P = 0.0024). CONCLUSION: The place of epoprostenol in pregnancy might be in patients with severe hypertension and tachycardia and in those requiring acute control of severe hypertension on the operating table before general anaesthesia.
Adult↗
Dietary intake of vitamin A in African pre-school children in Umlazi, South Africa.
Vitamin A deficiency has been shown to have an impact on morbidity and mortality and therefore prevalence rates are important for public health policy. We report the use of a 7-day recall, dietary questionnaire, which was validated and administered to 203 randomly selected urban African pre-school children in Umlazi, South Africa. Common vitamin A containing foods eaten were leafy green vegetables, pumpkin, sweet potato, mangoes and chicken liver. Although the mean daily intake of vitamin A was adequate, 19 children had intakes below the recommended dietary allowance (RDA). Thirteen of these children had eaten liver in the previous week, and as such were probably not at risk. It is therefore estimated that only 6 of the children (3%) were at risk for developing vitamin A deficiency.
Black or African American↗
Ipratropium bromide delivered by metered-dose aerosol to infant wheezers.
Two methods of administration of ipratropium bromide (Atrovent; Boehringer Ingelheim) to wheezing children less than 25 months of age were compared: (i) the conventional nebulisation (15 children); and (ii) a metered-dose aerosol plus spacer and mask (MDA group, 17 children). The drug induced a significant and similar fall in respiratory rate in both groups. Transcutaneous carbon dioxide pressure was also reduced significantly but was more marked in the MDA group. This increase in alveolar ventilation was similar in those less than 12 months as in older children; in those with recurrent or with first time wheezing; and in those with radiological evidence of pneumonia. Clinical assessment of bronchospasm and recession was recorded as improved in over 80% of both groups. The MDA delivery of ipratropium bromide was as effective as nebulisation and was more convenient, since it required less time and equipment. It was also well accepted by the small patients.
Aerosols↗
Neonatal group B streptococcal infections in Indian (Asian) babies in South Africa.
In this, the first report of group B streptococcal (GBS) infections in Asian neonates in South Africa, the incidence was 2.65/1000 live births over a period of 3.5 years. Early onset disease (EOD), defined as arising less than or equal to 5 days after birth, was present in 79% cases; in most of these, the onset was before the age of 24 h. One baby presented with two episodes of late onset GBS infection. The incidence of culture-proven neonatal septicaemia during the same period was 12.3/1000 live births, GBS being commonest organism isolated. It was also the most frequent cause of bacterial meningitis in the newborn, accounting for 89% cases. Although neurological signs were present in 40% patients with EOD, only 13.3% had CSF-culture-positive meningitis. Radiographic features of hyaline membrane disease were found in half of the babies with EOD and for whom a chest radiograph was performed, while one had a pneumothorax. The overall mortality was 13.2% which is much lower than that reported in other series.
Female↗
An approach to select the appropriate statistical method for testing bioequivalence.
Since most bioavailability studies are usually done with only a limited number of volunteers (usually 10-30), the statistical properties of the calculated bioavailability parameters are not well defined. The established statistical methods to test bioequivalence are usually based on either the assumption of normality or a symmetrical distribution. However, the decision of which method to apply, depends primarily on the distributional assumption of the data. In this study, an approach is followed where the small data base of a limited number of volunteers is expanded by adding pseudo-volunteers by "bootstrap" simulations. From such a larger data base it is easier to determine the statistical distributional properties of bioavailability parameters, which in its turn leads to the identification of an appropriate statistical method. With more certainty on which statistical method to apply, the original data can be used more effectively in testing for bioequivalence. In this paper, comparisons are made between the distributions of bioavailability parameters of an actual 60-volunteer study and those of two simulated data sets. Each such data set contained a random sample of 10 volunteers each (from the 60 volunteers), together with 50 pseudo-volunteers. These 50 volunteers were simulated from the random sample of 10 real volunteers. Good correspondences were obtained when comparing these two data sets with the original data, which indicated the validity to use this approach in bioavailability studies where a small number of volunteers had been used. This method proved useful to define the distributional properties for a relative small number of parameter-values available.
Biological Availability↗
The nutrient intake of a group of older South African hospitalized persons.
Data from a dietary survey of patients in a rehabilitation hospital indicated that their nutrient intake was very low in comparison with the RDAs. Those patients are at risk of developing specific nutritional deficiencies. Recommendations to improve the nutrient intake of this group of elderly persons are given. Even if the "perfect diet" were served, however, a patient's food intake might not be sufficient to meet the RDAs because of lack of appetite or because of elevated requirements owing to various illnesses, multiple drug use, and physiological changes associated with aging. In such a patient, the potentially beneficial use of supplements must be considered.
Aged↗
Anthropometric measurements, dietary intake and biochemical data of South African lacto-ovovegetarians.
A group of South African lacto-ovovegetarians were studied. They did not differ from a group of control subjects in respect of height, weight, Quetelet index or percentage body fat. Dietary analysis indicated that the vegetarians had significantly higher intakes of folic acid and ascorbic acid, and significantly lower intakes of vitamin B12 and zinc compared with the controls. Vegetarians should give special attention to the intake of certain nutrients such as iron, vitamin B12 and zinc, which may be in a less available form or in lower concentrations in plant foods. Vegetarians had lower serum vitamin B12 levels (not significant in males) and ferritin levels (not significant in females) than the controls. Plasma levels of cholesterol, high-density lipoprotein (HDL) cholesterol and triglycerides did not differ between the two groups.
Adult↗
Effect of iron and pH on the survival of Vibrio cholerae in water.
Many physicochemical factors affect the survival of Vibrio cholerae in the aquatic environment. An attempt was made to study the combined effect of pH and iron on the survival of V. cholerae in water in a laboratory environment. None of the 6 strains of V. cholerae used survived at pH 5.0; survival of all strains increased with increasing pH. The effect of ferric oxide on survival was significant for V. cholerae O1 only, not for non O1 strains. The longest survival of V. cholerae non O1 was 82 d, of El Tor V. cholerae 68 d, and of classical V. cholerae 56 d.
Ferric Compounds↗
Periventricular hemorrhage in a developing world. Is drug intervention appropriate?
This study examined the factors associated with the development of periventricular hemorrhage (PVH) in black low-birth weight infants from a disadvantaged community. In addition, the use of drugs as a preventive strategy for the development of PVH was addressed. A total of 177 babies weighing less than 1.5 kg were studied. Eighty (45.2%) were found to have PVH. Grade I PVH was diagnosed in 33 (41.3%), grade II in 37 (46.3%) and grade III in 10 (12.4%) of the babies studied. The overall mortality was 32% (57/177). Mortality of babies with grade I was 33% (11/33), grade II 63% (22/35) and 70% (7/10) for grade III. In those with normal scans the mortality was 18% (17/96). Babies with a lower weight had the severer grade of PVH (P < 0.05). Univariate analyses suggested that lower weight and gestational age, mode of delivery, asphyxia, RDS, shock, hypothermia and the need to administer plasma were the risk factors for both mortality and PVH. However, multiple logistic regression analysis revealed that lower weight (P < 0.001, RR 6.135), asphyxia (P < 0.0004, RR 6.849) and the administration of plasma (P < 0.0026, RR 6.024) were the major factors contributing to death. For the development of PVH weight (P < 0.0001, RR3.719) and the need for plasma (P < 0.03,RR2.079) were crucial. Obstetric complications, place of delivery and booking status did not play a significant role in PVH. The findings in this study suggest that drug intervention in the future may not be appropriate and should be considered when care of the small baby has improved.
Acidosis↗
Seroepidemiological study of Helicobacter pylori infection in South African children.
The seroepidemiology of Helicobacter pylori infection was studied in 681 randomly selected Black children from newborn to 13 years of age (333 boys, mean age 8.05 years, and 348 girls, mean age 7.76 years) in KwaZulu/Natal, South Africa. H. pylori infection was identified serologically using an enzyme-linked immunosorbent assay to detect the presence of immunoglobulin G against H. pylori. Demographic information collected included age, gender, family income, overcrowding, educational level, and possession of domestic pets. The seroprevalence of H. pylori infection was compared to a known faecal-orally transmitted infection, hepatitis A virus (HAV); 66% of the children were seropositive for H. pylori. There was an age-specific increase in H. pylori infection, with more than 80% of children being infected by the age of 10 years. There was no significant difference (P = 0.338) in the seropositivity of H. pylori infection between boys (68%) and girls (64%), nor was there any significant difference in H. pylori infection related to pets, level of parents' education, crowding, and income, by either univariate or multivariate analysis. However, there was a significant association (P < 0.00001) between the seroprevalence of H. pylori and HAV infections, suggesting similar modes of transmission.
Adolescent↗
Models to predict the intensity of Plasmodium falciparum transmission: applications to the burden of disease in Kenya.
There is an increasing need to provide spatial distribution maps of the clinical burden of Plasmodium falciparum malaria in Africa. Recent evidence suggests that risk groups and the clinical spectrum of severe malaria are related to the intensity of P. falciparum transmission. Climate operates to affect the vectorial capacity of P. falciparum transmission and this is particularly important in the Horn of Africa and parts of East Africa. We have used a fuzzy logic climate suitability model to define areas of Kenya unsuitable for stable transmission. Kenya's unstable transmission areas can be divided into areas where transmission potential is limited by low rainfall or low temperature and, combined, encompass over 8 million people. Among areas of stable transmission we have used empirical data on P. falciparum infection rates among 124 childhood populations in Kenya to develop a climate-based statistical model of transmission intensity. This model correctly identified 75% (95% confidence interval CI 70-85) of 3 endemicity classes (low, < 20%; high, > or = 70%; and intermediate parasite prevalences). The model was applied to meteorological and remote sensed data using a geographical information system to provide estimates of endemicity for all of the 1080 populated fourth level administrative regions in Kenya. National census data for 1989 on the childhood populations within each administrative region were projected to provide 1997 estimates. Endemicity-specific estimates of morbidity and mortality were derived from published and unpublished sources and applied to their corresponding exposed-to-risk childhood populations. This combined transmission, population and disease-risk model suggested that every day in Kenya approximately 72 and 400 children below the age of 5 years either die or develop clinical malaria warranting in-patient care, respectively. Despite several limitations, such an approach goes beyond 'best guesses' to provide informed estimates of the geographical burden of malaria and its fatal consequences in Kenya.
Child, Preschool↗
Malaria control: bednets or spraying? Trial in Kwazulu-Natal, South Africa.
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Bedding and Linens↗
Atherosclerosis. Chronic effects of fish oil and a therapeutic diet in nonhuman primates.
Prolonged testing of marine fish oil (FO) as a dietary supplement is necessary because of widespread claims that it is antiatherogenic. The basis for such claims is inadequate because atherogenesis is chronic and may not respond to short-term changes induced by dietary treatments. A proven (vervet) model of atherosclerosis promoted by an atherogenic diet (AD) was used to test dietary supplementation with Atlantic pilchard FO for 20 months in 47 omnivorous nonhuman primates. Responses were controlled against known favorable effects of changing from the AD to a therapeutic diet (TD). Compliance was achieved, and tissue responses to the FO dose were confirmed. Compromise of reflex vasoconstriction by atherosclerosis was demonstrated for the first time in the model. Aortic, peripheral, coronary, and cerebral atherosclerosis were assessed by light microscopy and computerized image analysis. No component of atherosclerosis regressed after dietary FO, and several deteriorated. After a change to the TD, stainable lipid was cleared from aortas and there were few lipophages, but advanced atherosclerosis was not reduced. Male vervets developed more severe atherosclerosis than did females, and the association among aortic, peripheral, and coronary atherosclerosis was positive in males. Females were resistant to coronary atherosclerosis. Only mild cerebral atherosclerosis was detected. In conclusion, the FO used was not antiatherogenic in the model, and there is a need for caution. The TD regresses some components of atherosclerosis, but it was not effective against fibrosis, mineralization, and cholesterol crystals within 20 months.
Animals↗