Biomedical subjects

P J Becker

Publications and source records attributed to P J Becker.

At least 55 records · Page 3Linked to original sources

PubMed1995

Penetrating stab wounds of the chest--when should chest physiotherapy commence? A comparative study.

In an effort to optimise the physiotherapy management of patients with penetrating stab wounds to the chest, 26 male patients, aged between 18 and 30 years, were randomised to one of two groups on admission to Hillbrow Hospital. The patients in group I received chest physiotherapy immediately after insertion of the intercostal drain, while patients in group II received chest physiotherapy 9-12 hours after insertion of the drain as is currently the normal hospital procedure. Mean duration of intercostal drainage in group I was 40 hours and that in group II 65.92 hours. Patients in group I had significantly shorter intercostal drainage times than patients in group II (P = 0.0001). Patients in group I had a mean hospital stay of 43.96 hours while patients in group II had a mean hospital stay of 77.53 hours (P = 0.0001). There was a significant difference in the duration of hospitalisation between the two groups, this being shorter in group I than in group II. The prevalence of spiking temperatures was also significantly lower in group I than in group II, since only 2 patients in group I but 8 patients in group II developed a spiking temperature (P = 0.0207). This study suggests that an aggressive approach of immediate chest physiotherapy in these patients has definite beneficial results.

Adolescent↗

PubMed1995

Follow-up of conservatively treated sleep apnoea patients.

Polysomnograms have been recorded at our laboratory since 1985 for the diagnosis of sleep apnoea. Until the recent availability of continuous positive airway pressure devices in Johannesburg, it appeared that some of our subjects were receiving only conservative or no treatment. Structured interviews were conducted with 63 patients with positive polysomnographic findings of sleep apnoea/hypopnoea (SAH), and, where possible, with sleeping partners. Information was obtained about the patients' understanding of the diagnosis by the referring doctor, the recommended treatment and psychosocial consequences. The primary reason for the initial consultation was excessive daytime sleepiness (43%). Diagnoses following polysomnography included SAH (65%) and narcolepsy (6%), while 10% were told they had nothing to be concerned about. Some form of treatment was recommended to 80% of patients, usually weight loss (60%) or medication (59%). Psychosocial consequences were prominent and included a perception of reduced work capacity (62%) and compromised safety (56%). At the time of the interview 90% of patients were experiencing one or more symptoms associated with SAH. These findings support the serious nature of SAH and confirm the need for adequate treatment centres in South Africa.

Adult↗

PubMed1995

An assessment of the statistical procedures used in original papers published in the SAMJ during 1992.

OBJECTIVE: To assess the statistical procedures used in original papers published in the SAMJ. DESIGN: Descriptive study based on a random sample of 100 papers from the 153 papers with methodological content that were published in the SAMJ during 1992. RESULTS: This review showed that 34% (95% CI (25%; 43%)) of papers used no statistical procedure at all or used simple descriptive statistics only. In sampling methods, there was a predominance of the use of the period sampling method as opposed to probability sampling methods. Inappropriate statistical methods were used in 15% (6%; 24%) of papers, while in 16% (9%; 23%) statistical procedures and in 13% (6%; 20%) the sampling methods used could not be identified. Inaccurate graphical methods were used in 17% (6%; 28%) of papers. Confidence intervals and power calculations are used far too infrequently, in 33% (19%; 47%) and 11% (3%; 19%) of appropriate papers respectively. If the Journal's readers are at least familiar with simple descriptive statistics, contingency table analysis, simple epidemiological statistics, t-test procedure and confidence interval calculation and interpretation, they will have a complete understanding of the statistical content of 60% of original articles published in the Journal. CONCLUSION: Guidelines for the statistical treatment of reported data and the statistical review of articles before publication will assist substantially in improving the quality of statistical analysis. More intensive use of available biostatistical and epidemiological expertise at the study design and analysis stages is needed to shift the emphasis from descriptive research to analytical investigation.

Evaluation Studies as Topic↗

PubMed1995

Cephalometric analysis of a Sotho-Tswana group.

A cephalometric study was conducted on 50 male and 54 female Sotho-Tswana children 11-16 years of age. The subjects were selected for excellence of occlusion and balance of facial proportions. Various analyses, including Steiner, Wits, and McNamara, were used for the evaluations. The mean measurements were compared with those of other Southern African Black groups and Caucasoids. Our study shows that cephalometric analyses for other groups cannot be used with confidence for the Sotho-Tswana people and our data provides norms for them.

Adolescent↗

PubMed1995

Bond strength values: should they be considered in material selection?

This study determined shear bond strengths of 4 glass ionomer cements under standardized conditions and compared the results with data derived from the product manufacturers. Flat dentine planes were prepared on the buccal surfaces of 40, unerupted, surgically removed, human third molars. Ten cylinders of Fuji II LC (FII), Aqua Ionofil (AI), Variglass VLC (VA) and Vitremer (VI) were bonded to dentine surfaces. The specimens were stored in distilled water for 96 hours and their shear bond strengths were then determined using an Instron testing machine. FII LC achieved the highest (15 MPa) and VA the lowest (2 MPa) mean shear bond strength values and those for Aqua Ionofil and Vitremer were 5 to 6 MPa. The manufacturers have reported lower bond strengths for FII and AI and higher values for VI and VA. This study showed that in view of differences in test methods bond strength test values are not comparable and we recommend that they should not be used as the only criterion for material selection.

Acrylic Resins↗

PubMed1994

Pyelonephritis: renal urokinase activity in rats on essential fatty acid diets.

This study was undertaken to assess whether additions of different oils to the diets of male rats would affect the renal urokinase (UK) activity of healthy and pyelonephritic kidneys. Four groups of fatty acid diets were studied: fat-free, coconut oil, fish oil and evening primrose oil (EPO). Pyelonephritis was obtained by unilateral extrarenal urinary obstruction and subcutaneous injection of Escherichia coli. The UK activity of the non-obstructed kidneys did not differ statistically between rats infected and not infected with bacteria (P > 0.056), except within the coconut oil group. A statistically decreased UK activity was obtained with bacteria injected animals on a coconut oil diet (P < 0.0001). This phenomenon, namely a decrease in UK activity, was also seen with pyelonephritic kidneys of rats on fat-free, coconut and fish oil diets (P < 0.0065). However, the UK activity of the obstructed kidneys with and without infection in the EPO group remained similar (P = 0.8477). These results suggest that the UK activity in infection-induced renal stones may be restored by EPO containing diets and may be of high relevance in the prevention and treatment of infection-induced renal stones. This revelation now needs to be more fully investigated.

Animals↗

PubMed1994

Survival of fixed implant-supported prostheses related to cantilever lengths.

Various lengths of cantilevers for fixed implant-supported prostheses have been recommended in the literature. No scientific data are available for selecting specific lengths, and different views are reported. Authors contend that longer cantilevers lead to increased risk of failure. This study examined survival of fixed implant-supported prostheses using different cantilever lengths and offers clinical support for the contention.

Dental Implantation, Endosseous↗

PubMed1994

Randomized double-blind comparison of tiaprofenic acid and diclophenac sodium after third molar surgery.

OBJECTIVE: This study compares the effectiveness of tiaprofenic acid with diclophenac sodium over a 7-day period with respect to pain, facial swelling, and trismus. STUDY DESIGN: Sixty patients who required general anesthesia for removal of bilateral impacted third molar teeth were included. Intraoperatively, they received intramuscular injections of either tiaprofenic acid or diclophenac sodium followed respectively by tiaprofenic acid tablets for 5 days and placebo for an additional 2 days or diclophenac sodium tablets for the full 7 days. Surgical and anesthetic techniques were standardized. Pain levels were compared hourly for 4 hours postoperatively and thereafter twice daily for 7 days. Changes in facial swelling and trismus were compared on days 2 and 7 postoperatively. RESULTS: No statistically significant difference was found between the two treatment groups with respect to pain or facial swelling. Only with respect to recovery in mouth-opening ability (trismus) from day 2 to day 7 did diclophenac sodium reveal a statistically significant advantage (p = 0.0452).

Administration, Oral↗

PubMed1994

Observations on the techniques used in the qualitative and quantitative diagnosis of schistosomiasis.

For many years, the Visser filter has been used in various laboratories in South Africa for the qualitative and quantitative diagnosis of human schistosomiasis. In the present study, the effectiveness of the Visser filter was compared with those of the urinalysis method for urine (involving the use of small transparent filters in Millipore filter holders attached to 10-ml syringes) and the Kato-Katz thick smear method for faeces. The Visser filter was the most sensitive in detecting ova in human excreta. Furthermore, there was little agreement between the egg counts obtained using the Visser filter and those obtained with the other two techniques. The Visser filter owes its effectiveness and superior sensitivity to the fact that, compared with the other two techniques, larger quantities of urine (total bladder contents) and stool (up to 5 g) can be easily processed.

Child↗

PubMed1994

Vitamin B-6 supplementation and theophylline-related effects in humans.

This study investigates whether vitamin B-6 supplementation reduces the stimulatory effects of theophylline (a pyridoxal kinase antagonist) on the nervous system. Twenty young, healthy adults entered this double-blind, randomized, crossover study but only 15 completed the experiment. The dependent measures were a battery of psychomotor tests, electrophysiological tests, and self-report questionnaires. Most tests, including spectral electroencephalography, aspects of the electromyograph, the Sternberg Test of information processing, and questionnaires of sleep quality and daytime sleepiness failed to distinguish between vitamin B-6 and placebo supplementation. However, theophylline-related tremor was markedly reduced (p < 0.01) with vitamin B-6 supplementation after a single dose of theophylline and a similar but nonsignificant trend was observed with repeated doses. There was a tendency for vitamin B-6 supplementation to reduce many side effects related to nervous system function. These findings suggest that vitamin B-6 supplementation with theophylline therapy may have some beneficial effects.

Adult↗

PubMed1994

Vitamin requirements for the treatment of hyperhomocysteinemia in humans.

We have previously shown that a modest vitamin supplement containing folic acid, vitamin B-12 and vitamin B-6 is effective in reducing elevated plasma homocysteine concentrations. The effect of supplementation of the individual vitamins on moderate hyperhomocysteinemia has now been investigated in a placebo-controlled study. One hundred men with hyperhomocysteinemia were randomly assigned to five groups and treated with a daily dose of placebo, folic acid (0.65 mg), vitamin B-12 (0.4 mg), vitamin B-6 (10 mg) or a combination of the three vitamins for 6 wk. Folic acid supplementation reduced plasma homocysteine concentrations by 41.7% (P < 0.001), whereas the daily vitamin B-12 supplement lowered homocysteine concentrations by 14.8% (P < 0.01). The daily pyridoxine dose did not reduce significantly plasma homocysteine concentrations. The combination of the three vitamins reduced circulating homocysteine concentrations by 49.8%, which was not significantly different (P = 0.48) from the reduction achieved by folate supplementation alone. Our results indicate that folate deficiency may be an important cause of hyperhomocysteinemia in the general population.

Adult↗

PubMed1994

South African Indians show a high prevalence of NIDDM and bimodality in plasma glucose distribution patterns.

OBJECTIVE: To determine the prevalence of diabetes mellitus and impaired glucose tolerance (IGT) and to test for bimodality in the plasma glucose distribution in South African Indians. RESEARCH DESIGN AND METHODS: Subjects were selected by systematic cluster sampling in various areas of Durban. They underwent a modified glucose tolerance test whereby fasting and 2-h postglucose (75 g) plasma glucose levels were measured. The program MIX was used to test for bimodality in the plasma glucose distribution. RESULTS: We tested 2,479 subjects (1,441 women and 1,038 men). Based on the revised World Health Organization criteria, the crude prevalence of diabetes mellitus was 9.8%, and the crude prevalence of IGT was 5.8%; the age- and sex-adjusted prevalence was 13.0 and 6.9%, respectively. IGT was significantly more common in men (7.6%) than in women (4.4%). Obesity was a feature of both diabetes mellitus and IGT, particularly in women. Both fasting and 2-h plasma glucose values did not conform to a single normal distribution pattern in any age-group, whereas unequivocal evidence of bimodality was seen in the 55- to 74-year age-group of both sexes for fasting and 2-h glucose and also in the 2-h levels of men in the 25- to 34-year age-group. CONCLUSIONS: This study has highlighted a high prevalence of non-insulin-dependent diabetes mellitus in South African Indians and bimodality in the plasma glucose distribution.

Adolescent↗

PubMed1994

Interposition of 'narrow' cycloperistaltic segments into isolated segments of jejunum--influence on fluid perfusion.

Two isolated segments of jejunum with the ends exteriorised as jejunostomies were created in each of 8 dogs. Towards the end of one of the two, a cycloperistaltic (C-P) segment, with a diameter 70% of that of the jejunum, was interposed. Fluid containing C-labelled polyethylene glycole [corrected] was infused at 4 ml/min through each of the 16 preparations and the results were compared. The presence of a C-P segment significantly reduced the volume of output (with C-P segment--mean (+/- standard deviation) 155.27 +/- 14.81 ml/h v. without C-P segment--210.09 +/- 19.41 ml/h) (P < 0.001) and increased absorption (with C-P--45.44 +/- 20.86 ml/h v. without C-P--20.48 +/- 8.42 ml/h) (P < 0.001) and pooling (with C-P--39.29 +/- 16.99 ml/h v. without C-P--9.42 +/- 17.16 ml/h) (P < 0.001). The C-P segment therefore delayed the passage of the perfused fluid.

Anastomosis, Surgical↗

PubMed1994

Malaria control and longitudinal changes in levels of DDT and its metabolites in human serum from KwaZulu.

Blood samples were obtained on four occasions over a 12-month period from individuals living in KwaZulu, South Africa, who had been exposed to DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) as a consequence of its use in their homes to control transmission of malaria. The longitudinal changes in serum DDT and its major metabolities, DDE and DDD, were determined. No additional risk was considered to have been presented by the increases that occurred following application of the pesticide. There were significant increases in DDT, DDE and sigma DDT (DDT + its metabolites) for the age group > or = 21 years, but for the age group 3-20 years a reduction in serum levels occurred over 12 months. Two concurrent processes probably govern the increase and decrease in serum levels, and the relative contributions of each interchange as the individual becomes older. The results suggest that children in KwaZulu experience conditions that differ from those of their parents, as well as from those that affect children in developed countries. In consequence, it is desirable that risk assessments of vector control chemicals consider all sectors of a population.

Adolescent↗

PubMed1994

Visual function and long-term chloroquine treatment.

Ophthalmic examinations and selected tests of visual function were performed on 64 patients with rheumatoid arthritis who had received daily doses of 200 mg chloroquine sulphate for periods ranging from 3 to 11 months. Visual fields were determined by Humphrey automated perimetry and Amsler grids and a further battery of four tests of macular function (visual evoked potentials, critical flicker fusion threshold, Cambridge contrast sensitivity and the macular dazzle test) were administered. No case of retinal pigmentary abnormalities plus visual loss was found, but 2 patients were advised to cease chloroquine therapy on the basis of funduscopic findings. A small group of patients with relatively poor scores on one or more tests had normal visual fields and ophthalmic findings. There were no significant partial correlations between test results and the cumulative dose of chloroquine. These results support the opinion that currently recommended doses of chloroquine pose a minimal risk of retinal toxicity.

Adolescent↗

PubMed1994

The effect of eugenol containing and non-eugenol temporary cements on the resin-enamel bond.

This study was undertaken to compare the effect of eugenol containing and non-eugenol temporary cements on the bond strength of three brands of luting cements to enamel. Flat enamel surfaces were prepared on 90 surgically removed, unerupted, human third molar teeth. The teeth were randomly divided into three groups of thirty. The flat enamel surfaces in two of the groups were treated with either a eugenol containing or non-eugenol temporary cement and the third group was left untreated. The teeth were stored in water for 7 days and the cements then removed and all surfaces etched. The teeth were divided into 9 sub-groups of 10 each and one of the three resin cements was then bonded to each sub-group. The relevant shear bond strengths were determined after 7 days. The results indicated that prior use of a eugenol containing temporary cement reduced the resin cement-enamel bond strengths. No differences were found between the bonds achieved by the three brands. It was concluded that eugenol containing temporary cements should not be used prior to bonding with resin luting cements.

Analysis of Variance↗

PubMed1994

Shear and tensile bond strengths of two resin cements to a high gold alloy: an in vitro study.

The shear and tensile bond strengths of two resin cements to a high gold alloy with differently prepared surfaces were compared. Eighty buttons were cast from Argident Yellow 1 (gold 83.5 per cent). The surfaces of 40 buttons were sandblasted and the rest were silicoated. Forty cylinders each of F21 and Panavia EX were bonded to the prepared gold alloy surfaces and the specimens stored in distilled water for 24 hours. Half the specimens were then tested to failure using a shear test and the other half using a tensile test. The two cements achieved significantly higher shear and tensile bond strengths to the silicoated metal surfaces. Both cements attained similar shear bond strengths, but F21 achieved significantly stronger tensile bonds than Panavia EX to the differently treated metal surfaces. It is concluded that silicoating of high gold alloys is preferable to sandblasting for resin retention, and that bond strength data from different test methods are not comparable.

Analysis of Variance↗

PubMed1994

The effect of titanium on the growth of plaque micro-organisms in vitro.

The effect of titanium on the growth of plaque organisms was studied in vitro. Thioglycollate broth containing either titanium or glass cylinders was inoculated with plaque micro-organisms and incubated aerobically and anaerobically at 37 degrees C for 6 hours. Growth was measured by observing an increase in turbidity of the broth. Cultures grew more vigorously aerobically than anaerobically. In the presence of titanium there was also more growth aerobically than anaerobically. There was no significant difference between the turbidity values obtained in the presence or absence of titanium suggesting that titanium does not influence the growth of plaque micro-organisms significantly.

Agar↗