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Biomedical subjects

P J Becker

Publications and source records attributed to P J Becker.

At least 37 records · Page 2Linked to original sources
PubMed1997

Hyperhomocysteinaemia in black patients with cerebral thrombosis.

Hyperhomocysteinemia is regarded as a risk factor for stroke but its pathogenetic role has not yet been established in Black patients. We studied 24 Black patients admitted with cerebral thrombosis, and compared them with age- and sex-matched apparently healthy controls from the same community. Total homocysteine (tHcy) (free homocysteine, protein-bound homocysteine, the disulfide homocystine and the mixed disulfide homocysteine-cysteine) concentration was 10.91 (4.95-23.05) mumol/l in the stroke patients and 8.73 (3.95-15.10) mumol/l in controls (p = 0.031). This difference could not be explained by differences in vitamin B12, vitamin B6 or folate status. A subgroup of nine stroke patients with hypercreatininaemia (> 90 mumol/l, 75% of control concentrations) had significantly higher plasma tHcy concentrations [median (range) 9.10 (5.40-15.10) mumol/l] compared with controls [8.65 (3.96-13.89) mumol/l] (p = 0.002). Plasma tHcy concentrations of stroke patients with normal serum creatinine concentrations were not significantly different to those of controls. Hyperhomocysteinemia in Black patients with stroke may be partially caused by renal insufficiency. Therefore, while hyperhomocysteinemia may increase the risk of stroke, it is unlikely to be a primary initiating factor.

Black People↗
PubMed1997

Growth, feeding practices and infections in black infants.

OBJECTIVE: To investigate the growth, early feeding practices and prevalence of infections in black infants. DESIGN: Longitudinal study with prospective documentation of data. SETTING: Kalafong Hospital, Pretoria. PATIENTS: Term, appropriately grown infants with a positive rapid plasma reagin test on cord blood were enrolled. Infants who on follow-up did not have congenital syphilis were studied. RESULTS: At birth the mean weight-for-age Z-scores corresponded with those of the National Center of Health Statistics (NCHS) reference population and increased during the first 3 months. A fall-off in growth performance in respect of weight gain occurred from 3 months and continued until 15 months when the study was terminated. At 6 and 12 months, 86% and 81% of infants respectively were receiving breast-milk. By 3 months, 78% of infants were receiving a supplementary food. At 9 months, 40% of infants had experienced an infection during the preceding 3 months. During the study, upper airway infections comprised 74% of all episodes of infection. CONCLUSIONS: Compared with the NCHS reference population, black infants grow adequately during the first 3 months of life. This is followed by a persistent fall-off in growth performance associated with the introduction of supplementary food.

Anthropometry↗
PubMed1997

Diagnostic disagreement--the lessons learnt from malaria diagnosis in Mpumalanga.

Diagnostic tests that require human interpretation will always be susceptible to error. This may lead to delays in initiating effective therapy for potentially fatal conditions. The Malaria Control Programme in South Africa has historically relied on the microscopic examination of Giemsa-stained thick blood smears to confirm the clinical diagnosis of malaria. The level of agreement of malaria laboratory diagnosis performed by the four laboratories serving the Mpumalanga Province Malaria Control Programme was investigated. The disagreement between the laboratories argues in favour of a uniform training and quality assurance programme or the introduction of alternative diagnostic modalities. It should also serve as a caution against diagnostic complacency in other public health programmes.

Clinical Laboratory Techniques↗
PubMed1996

Facial soft-tissue thicknesses in the adult male Zulu.

The morphometric method of forensic facial reconstruction rests heavily on the use of facial soft tissue depth measurements. In reconstructing the Negroid face, much use has been made of the tables of soft tissue thickness of American Negroid cadavers. However, the genetic complexities of American blacks are well known. In addition it is felt that measurements made on the living are of more value than those made on the dead. In view of this it was decided to set up a table of norms for facial soft tissue depths of the living Zulu, an African Negroid who has remained relatively free from genetic admixture with other populations. The tightly controlled sample consisted of 55 healthy male Zulus, aged 20 to 35. Tissue depths at established landmarks were measured from lateral and oblique cephalometric radiographs. These were then combined with ultrasonic readings at other landmarks on the subject's face to yield a comprehensive set of tissue depth data. This paper presents a set of average facial soft tissue depth measurements from the Zulu face that results in the development of a new profile. It also provides a method for linking two systems of measurement.

Adult↗
PubMed1996

Increased expression of aphidicolin-induced common fragile sites in Tourette syndrome: the key to understand the genetics of comorbid phenotypes?

In a comparison of 80 common aphidicolin-induced fragile sites (FS) between 26 DSM-IV Tourette syndrome (TS) and 24 control individuals, the mean of the summed break frequencies following mild aphidicolin pretreatment was significantly higher in TS individuals than in controls (P < 0.001). Other breakpoints encountered during this study, i.e., random breaks, breaks corresponding to rare FS, and breakpoints recorded by others but not listed as common FS according to the Chromosome Coordinating Meeting [1992] were listed as category II breakpoints. By using the most significantly different mean FS breakage figures between TS and control individuals, further stepwise discriminant analysis allowed identification of TS individuals from only a few sites in both the common FS and category II breakpoint groups. Future research needs to focus on confirmation of altered common fragile site expression in association with behavioral variation, whether expression of certain discriminatory sites concurs with specific comorbid disorder expression; the nature of the molecular alterations at these FS and the implications of a genomic instability phenotype for the mapping of a primary TS gene or genes.

Adult↗
PubMed1996

Intergroup comparisons of carpal tunnel dimensions.

Although it is a common disease entity worldwide, idiopathic carpal tunnel syndrome is rarely seen in black South Africans. This study compares anatomic dimensions of the carpal canal in black and white population groups, using computed tomography. No significant anatomic differences were found between the groups tested; thus, other explanations need to be sought to explain the difference in occurrence of carpal tunnel syndrome in these groups. A parameter, the carpal canal index, was defined and may prove useful in future investigations of this region.

Adult↗
PubMed1996

Will an increased dietary folate intake reduce the incidence of cardiovascular disease?

Based on a meta-analysis of published studies, it has been estimated that approximately 10% of coronary artery disease cases are attributable to hyperhomocyst(e)inemia. It has also been calculated that food fortification with folate might reduce the number of cases of coronary artery disease in the United States by 50,000 per year. However, the use of statistical concepts to estimate the expected benefits of this intervention strategy may be misleading.

Cardiovascular Diseases↗
PubMed1996

Post-insertion visits in medicated complete denture wearers.

The effect of systemic disease and medication on the number of post-insertion visits was investigated in 157 patients requiring new complete dentures, who were referred to a specialist prosthodontic practice. We found that the number of recall visits increased with age, particularly in patients medicated for central nervous system or psychiatric disorders, and more so with cardiovascular diseases treated with diuretics.

Adult↗
PubMed1996

A comparison of the dimensional stability of three inlay pattern materials.

This study investigates the dimensional stability of 3 inlay pattern materials stored for different periods of time. Three indices were formulated to assess changes. These were: deviation and area change which both indicate a proportional contraction or expansion, and ratio which shows distortion. A brass master model was constructed to represent a cavity with 4 intersecting reference lines on the base, which were transferred to the bottom of the inlay pattern. The materials tested were Kerr's Type II blue inlay casting wax, Duralay (an autopolymerizing acrylic resin) and Modilux (a light-curing resin). Ten inlay patterns were prepared from each material in the brass master model cavity. Measurements of pre-determined points on the reference lines were recorded with a reflex microscope immediately after removal of the inlay patterns and then repeated at intervals of 1 hour and 24 hours. These measurements were compared to corresponding measurements on the brass master model and then converted into the three indices previously mentioned. Analysis of data showed that none of the materials distorted and that all the patterns underwent a proportional contraction, with wax contracting more than Duralay and Modilux. Significantly more contraction occurred at 24 hours than between onset (0 hour) and 1 hour. As contraction only occurred after 1 hour and wax contracted the most, it is recommended that Duralay or Modilux be used as the pattern material, especially if a delay in investing is anticipated.

Analysis of Variance↗
PubMed1995

Increased chromosomal breakage in Tourette syndrome predicts the possibility of variable multiple gene involvement in spectrum phenotypes: preliminary findings and hypothesis.

Increased chromosomal breakage was found in 12 patients with DSM-IV Tourette syndrome (TS) as compared with 10 non-TS control individuals with respect to untreated, modified RPM1-, and BrdU treated lymphocyte cultures (P < 0.001 in each category). A hypothesis is proposed that a major TS gene is probably connected to genetic instability, and associated chromosomal marker sites may be indicative of the localization of secondary genes whose altered expression could be responsible for associated comorbid conditions. This concept implies that genes influencing higher brain functions may be situated at or near highly recombigenic areas allowing enhanced amplification, duplication and recombination following chromosomal strand breakage. Further studies on a larger sample size are required to confirm the findings relating to chromosomal breakage and to analyze the possible implications for a paradigmatic shift in linkage strategy for complex disorders by focusing on areas at or near unstable chromosomal marker sites.

Adult↗
PubMed1995

A serosurvey of water-borne pathogens amongst canoeists in South Africa.

Certain health risks have been associated with recreational exposure to faecally polluted water. Canoeing in certain South African waters is considered to be a high risk activity with regard to schistosomiasis, gastroenteritis and possibly hepatitis. In a cross-sectional study, a serosurvey was conducted amongst canoeists to ascertain whether or not they had a higher seroprevalence to hepatitis A virus, Norwalk virus and Schistosoma spp. than non-canoeists. In comparisons between the two groups, a significant association could not be demonstrated between canoeing and antibody response to hepatitis A and Norwalk viruses (P-values for age-adjusted chi 2 were 0.083 and 0.219 respectively), but a significant association could be demonstrated between canoeing and the antibody response to Schistosoma spp. (P < 0.001; age-adjusted).

Adolescent↗
PubMed1995

Immunohistochemical detection of oncogene proteins and neuroendocrine differentiation in different stages of prostate cancer.

The progression of prostatic adenocarcinoma from localized disease to metastatic carcinoma appears to be a multi-step sequence. The expression of common oncogenes/oncosuppressor genes and the mediating effect of neuroendocrine tumor cells may play a role in this progression. The expression of the more frequently investigated oncogenes/oncosuppressor genes (p53, c-myc, c-erbB-2, bcl-2) and the presence of neuroendocrine cells were assessed in prostatic cancer tissue from patients with localized and metastatic cancer. These oncogenes/oncosuppressor genes were evaluated according to tumor stage and grade and their relationship to one another. Grade was not related to any of the oncogene markers or to the presence of neuroendocrine cells. Advancing stage was associated with a significant increase in p53 expression, while other markers remained constant in all stages. Neuroendocrine cells, p53, c-myc, c-erbB-2 and bcl-2 were rarely co-expressed at any stage of prostate cancer.

Carcinoma↗
PubMed1995

Effective homocysteine metabolism may protect South African blacks against coronary heart disease.

L-Methionine (0.1 g/kg body wt) was administered to young white [n = 18; mean (+/- SD) age 20.0 +/- 1.0 y] and black [n = 12; mean (+/- SD) age 22.0 +/- 1.3 y] volunteers who had a similar lifestyle and who did not differ significantly from each other with respect to plasma folate or vitamin B-12 concentrations. Blacks, however, had significantly lower plasma pyridoxal-5'-phosphate concentrations compared with whites (P < 0.001). Fasting plasma homocysteine concentrations in blacks and whites were not significantly different. The mean (+/- SD) maximum increase in plasma homocysteine concentration measured after methionine loading was significantly lower (P < 0.01) in blacks (11.0 +/- 3.6 mumol/L) than in whites (18.0 +/- 6.2 mumol/L). Six weeks of vitamin supplementation (1.0 mg folic acid, 400 micrograms vitamin B-12, and 10 mg pyridoxine/d) reduced the mean (+/- SD) fasting plasma homocysteine concentration from 9.6 +/- 3.5 to 7.2 +/- 1.6 mumol/L in whites (P < 0.05) and from 8.4 +/- 2.4 to 5.6 +/- 1.4 mumol/L in blacks (P < 0.01). The mean (+/- SD) maximum increase in plasma homocysteine concentration after methionine loading declined from 18.0 +/- 6.2 to 11.1 +/- 2.3 mumol/L (P < 0.01) in whites, but vitamin supplementation did not have a significant effect on the methionine-load test in black volunteers. A significant race-by-time interaction shows that blacks metabolized homocysteine more effectively than did whites, which may partly explain their relative resistance against coronary heart disease despite a high prevalence of obesity, hypertension, and smoking.

Adult↗
PubMed1995

Comparative radiographic analysis of parameters in feet with and without hallux valgus.

This study involved the radiographic examination of 118 feet from 110 urban African female patients. Fifty-two of the 118 feet showed radiographic evidence of hallux valgus (valgus angle > 15 degrees). The parameters compared between feet with and without hallux valgus were sesamoid position, pes planus deformity, metatarsal length, and the cuneiform-metatarsal articulation. All radiographs were standardized, weightbearing anteroposterior and lateral views. The results were statistically analyzed. The findings showed no difference between the hallux valgus and control groups with respect to sesamoid position relative to the second metatarsal, incidence of pes planus, relative length of the first metatarsal, and the first metatarsal-medial cuneiform articulation.

Adult↗
PubMed1995

Patterns of cytokine expression in community-acquired pneumonia.

BACKGROUND: Pneumonia continues to be a major cause of disease and death among patients worldwide. Aspects of the host response to infection, such as the release of cytokines, may be contributing to the persistent morbidity and mortality. METHODS: Plasma levels of cytokines interleukin (IL)-1 beta, IL-6, and tumor necrosis factor alpha (TNF-alpha) were measured in critically ill patients with pneumonia (ICUP; n = 12) and less severely ill patients with pneumonia (NONICUP; n = 8), and in 2 additional control groups of patients, viz, severely ill postoperative patients without evidence of infection (POSTOP; n = 11) and less severely ill patients with nonpneumonia infections (NONP; n = 9). All four groups of patients were studied in a multivariate one-way analysis of variance using the parameter vector: plasma IL-1 beta, IL-6, TNF-alpha, systolic blood pressure, diastolic blood pressure, plasma urea, creatinine, and temperature. Thereafter the significance of individual parameters were assessed by univariate analysis and pairwise comparisons. RESULTS: All cytokine concentrations were highest in the ICUP group. In the case of IL-1 beta, levels were significantly higher in the ICUP group when compared with the noninfected POSTOP group. The acute physiology and chronic health evaluation (APACHE) II scores were identical in these two groups (17 +/- 3 [SD] and 10 +/- 1, respectively, not significantly different). Intermediate levels were found in those groups with intermediate levels of infection. The IL-6 levels were not significantly different between the groups and in particular, the levels in the ICUP and POSTOP groups were similar. The TNF-alpha levels tended to mimic those of IL-1 beta, although the significant difference found was between the ICUP and NONICUP groups which had significantly different APACHE II scores (17 +/- 3 vs 4.4 +/- 1, respectively). No association between cytokine levels and patient mortality was demonstrated. CONCLUSION: Among the cytokines, IL-1 beta appeared to be associated with the severity of infection, IL-6 appears to reflect severity of stress whether of infection or noninfective origin, and TNF-alpha may be a marker of severity of pneumonia.

APACHE↗
PubMed1995

Results of B-vitamin supplementation study used in a prediction model to define a reference range for plasma homocysteine.

Because high plasma concentrations of homocysteine constitute an enhanced risk for premature coronary heart disease, it is necessary to establish a reference range for normal concentrations of plasma homocysteine. The frequency distribution of plasma homocysteine concentrations tails to the right, and the nonparametric approach is unsatisfactory for defining a normal plasma homocysteine reference range. By using subjects' responses to appropriate vitamin supplementation, we developed a mathematical prediction model to calculate the plasma homocysteine concentration that could be expected for each individual treated with a vitamin supplement. With this model, we can predict that plasma homocysteine concentrations will approach a normal frequency distribution with a 95% reference range (mean +/- 2 SD) of 4.9-11.7 mumol/L, provided the vitamin status of the study population is improved.

Adolescent↗