Search PubMed⌕ Search

Biomedical subjects

J P du Plessis

Publications and source records attributed to J P du Plessis.

14 recordsLinked to original sources
PubMed1998

Sterile vegetations in children with severe tetralogy of Fallot.

The finding of bland, sterile vegetations in children with severe tetralogy of Fallot is unexpected, and to our knowledge, has not been reported previously. Eight patients diagnosed with tetralogy between January 1993 and July 1997 had sterile vegetations proven by histological and microbiological evaluation, in their right ventricular outflow tracts. Four of these patients were experiencing severe hypercyanotic spells, and four had severely reduced effort tolerance at presentation. They all underwent cardiac catheterization and were submitted for surgical repair. At surgery, the vegetations were thought to be causing further narrowing of the already tight fibrotic infundibular stenosis. Two of these patients had evidence of damaged valves, without evidence of active endocarditis. Although initially sterile, these vegetations, may in some instances, become infected.

Adolescent↗
PubMed1997

Junctional ectopic tachycardia in six paediatric patients.

The presenting features and treatment responses of six children with junctional ectopic tachycardia are evaluated. Two of the patients were siblings and both presented in early childhood with cardiopulmonary failure. The elder sibling died, the surviving sibling was controlled on a combination of amiodarone, digoxin, and sotalol. The remaining four patients presented in later childhood with tachycardia induced cardiomyopathy. Two of the patients were diagnosed incidentally and have normalised their myocardial function on sotalol therapy. The other two presented in congestive cardiac failure. Radiofrequency His bundle ablation and insertion of a permanent pacemaker to control the arrhythmia was undertaken in the elder of the two patients. The remaining patient has had marginal recovery of myocardial function on a combination of amiodarone and sotalol treatment. Improvement in myocardial function may take several months and is dependent on control of the tachycardia in some patients. Sotalol, when used as single or combination treatment, was partially successful in four cases in reducing heart rate. None of the patients reverted to sinus rhythm.

Amiodarone↗
PubMed1997

The use of knowledge-based systems in medicine in developing countries: a luxury or a necessity?

Knowledge-based systems (KBSs) in medicine have received much attention over the past two decades, mainly because of the potential benefits that can be gained from using them. They may facilitate in increasing productivity in a medical environment, support the making of diagnoses and other types of medical decisions, assist in the training of medical professionals, and can even handle some routine tasks in a medical environment. However, some critical problems in this field have also been identified. For example, research indicated that some problems can be solved partially, but not completely, with existing artificial intelligence techniques. Another problem is that many of the existing medical information systems do not support the integration of KBSs in a natural way. Furthermore, the routine use of a medical KBS is complicated by legal issues. These and other problems contribute to what we experience today: a large proportion of the medical KB applications that are developed is never actually used in practice. This justifies questions such as: Should developing countries, having limited infrastructure and research resources, invest in medical KBSs research and development, or should this field be regarded as a luxury that only belongs to developed countries?, and: Can developing countries really benefit from the use of these systems? These questions are discussed in this paper. We highlight the main problems surrounding the development and use of medical KBSs. With the focus on developing countries we discuss potential benefits that could be obtained by investing in these systems and we offer guidelines for focusing research and development of medical KBSs.

Artificial Intelligence↗
PubMed1984

Effect of trans-unsaturated fats on experimental atherosclerosis in vervet monkeys.

Vervet monkeys ( Ceropithecus aethiops pygerethrus ) were placed on semipurified diets containing 14% fat of which 3.2 or 6.0% was present as trans-unsaturated fatty acid (t-FA). Two groups were fed the high and low levels of t-FA for a year and two others were fed t-FA for 6 months and then returned to the control diet for 6 months more. One other group was fed the control diet for a year. The control diet contained 14% fat which was a mixture of 72% olive oil and 28% corn oil. There were no significant differences in weight gain. Monkeys fed 6% t-FA or control diets for one year had lowest liver weights. Serum cholesterol and triglycerides in monkeys fed 3.2% t-FA for one year were 134 and 55 mg/dl, respectively; in monkeys returned to control diet after 6 months on 6% t-FA the values were 146 and 50 g/dl. Serum and triglyceride levels for the other 3 groups were 166 +/- 2 and 70 +/- 2 mg/dl. Liver cholesterol levels ranged from 4.0 mg/g (3.2% t-FA) to 4.7 mg/g (control) and 4.8 mg/g (6% t-FA). Lecithin:cholesterol acyltransferase (LCAT) activity was 59.0 microM/h for controls and ranged from 52.4 microM/h (3.2% t-FA) to 73.4 microM/h (6% t-FA). Cholesterol synthesis by liver slices was not affected by diet when the substrate was acetate. When mevalonate was used, the monkeys fed either level of t-FA for 12 months exhibited greatly reduced (about 80%) cholesterogenesis. The levels of t-FA in serum and liver reflected the amount in the diet. After being returned to control diet levels of t-FA in serum and liver of monkeys (fed 3.2% t-FA) fell by 97 and 94%, respectively, and those in serum and liver of monkeys fed 6% t-FA fell by 65 and 91%. There were no significant differences in aortic atherosclerosis or arteriosclerosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

Nutritional status of African populations predisposed to esophageal cancer.

Nutritional status indicators were assessed chemically in blood and urine taken from 625 Transkeians drawn from three age-groups in each of two regions: one with a moderate risk for esophageal cancer and one with a very high risk. Aggregate mean values for protein, albumin, vitamin A, and phosphorus were generally acceptable, but many subjects had inadequate (though not necessarily deficient) values for nicotinic acid (74% of subjects), magnesium (60%), vitamin C (55%), carotene (53%), riboflavin (41%), calcium (35%), and zinc (27%). Groups at highest risk for esophageal cancer had markedly lower serum magnesium and carotene concentrations and mildly depressed hemoglobin and hematocrit values, but such findings are not necessarily associated with esophageal cancer etiology. Possible intestinal malabsorption in the populations at highest risk may be associated with the unusually high fiber and phytate intake of the high-risk populations as well as with exposure to necrotizing mycotoxins. Thus, while protein and energy nutriture seem generally adequate, both the high- and moderate-risk populations had high incidences of multiple micronutrient malnutrition.

Adolescent↗
PubMed1982

Influence of native and randomized peanut oil on lipid metabolism and aortic sudanophilia in the vervet monkey.

Vervet monkeys (Cercopithecus aethiops pygerethrus) were fed cholesterol-free, semipurified diets containing 40% sucrose, 25% casein, 15% cellulose and 14% peanut oil (PNO), randomized peanut oil (RPNO) or corn oil (CO). After 4 months, serum cholesterol and triglyceride levels, serum lecithin-cholesterol acyl transferase (LCAT) activity and plasma lipoprotein lipase (LPL) activity were similar in all groups. Livers of monkeys fed CO converted 156% more acetate and 24% more mevalonate to cholesterol than those of monkeys fed RPNO. Cholesterogenesis in RPNO-fed monkeys was enhanced compared to PNO (68% from acetate; 62% from mevalonate). Incidence of atherosclerosis was 33% in monkeys fed RPNO, 80% in those fed CO and 90% in those fed PNO. Extent of sudanophilia was lowest in aortas of monkeys fed RPNO. Incidence of arteriosclerosis was 40% in monkeys fed CO, 56% in those fed RPNO and 70% in those fed PNO. Extent of aortic surface showing arteriosclerosis was highest in monkeys fed RPNO.

Animals↗
PubMed1981

Nutrient intakes among rural Transkeians at risk for oesophageal cancer.

The frequency of low nutrient intakes was investigated in areas of moderate and high oesophageal cancer incidence in Transkei by means of 24-hour recall and habitual intake studies in children and nursing mothers. The results in moderate- and high-risk regions were similar and habitual intakes of protein, energy, phosphorus, iron, thiamine and vitamin A were generally satisfactory. Intakes of less than two-thirds the Recommended Dietary Allowances (RDA) had a high frequency of inadequate intakes for calcium (90%), nicotinic acid (79%), riboflavin (55%) and ascorbic acid (50%). It is concluded that the possibility of long-standing deficiencies of the latter three vitamins playing a role in oesophageal carcinogenesis should be considered.

Adolescent↗
PubMed1981

Knowledge, attitudes and practices in relation to obesity and coronary artery disease. Results of a baseline study conducted among white parents and potential parents in the south-western Cape Province.

A baseline survey to determine the existing knowledge, attitudes and customs concerning different aspects of nutrition was conducted among adults in the south-western Cape Province. This was the first phase in a long-term research project launched with a view to developing a nutritional guidance programme in order to combat the high mortality rate attributed to coronary heart disease.

Adolescent↗
PubMed1979

Serum ferritin concentrations in black miners.

Serum ferritin concentrations were measured in 651 Black male miners who originated from rural areas throughout southern Africa and who were aged between 17 and 57 years. The mean serum ferritin concentration of 229 microgram/l was above the normal range reported for White subjects, and in 52,8% of the subjects the values were greater than 200 microgram/l. The serum ferritin concentration rose with age, as did the proportion of subjects in each age group who exhibited high values (more than 200 microgram/l). The lowest mean ferritin concentration (112 microgram/l) as well as the lowest proportion of high values (22,9%) were found in subjects from the most northerly area studied. Similarly, the highest mean proportion of high values (66,3%) was seen in the most southerly group studied. Calculations from the present data suggest that the degree of iron overload is currently greater in rural than in urban Black male subjects.

Adult↗
PubMedDate not supplied

Right-sided endocarditis due to Salmonella typhi.

A case of right-sided endocarditis due to Salmonella typhi is described involving a native tricuspid valve in a child who was human immunodeficiency virus negative with no evidence of intravenous drug addiction. The patient had classic features of typhoid and tricuspid regurgitation without clinical evidence of bacterial endocarditis. Transthoracic echocardiography confirmed the tricuspid regurgitation. However, transesophageal echocardiography was necessary to demonstrate the vegetations affecting the tricuspid valve leaflets that made possible the diagnosis of endocarditis. The infection was cured with intravenous ceftriaxone and oral amoxicillin.

Anti-Bacterial Agents↗