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Biomedical subjects

D du Toit

Publications and source records attributed to D du Toit.

At least 19 recordsLinked to original sources
PubMed1998

Foetal rat pancreatic transplantation: posttransplantation development of foetal pancreatic iso- and allografts and suppression of rejection with mycophenolate mofetil (MMF) and cyclosporine based immunesuppression.

Provided engraftment can be ensured, vascularization promoted, and ischaemic damage due to storage prevented, foetal pancreatic transplantation (FPT) has the potential to ameliorate the endocrine and metabolic disturbances in diabetic animal models including hyperglycaemia. In a syngeneic Wistar rat substrain (WAG) model (WAG --> WAG), FPT was capable of restoring normoglycaemia in diabetic rats rendered diabetic by streptozotocin (STZ). Posttransplantation growth and development of the foetal tissue was characterised by acinar atrophy, preservation of islet tissue, and development and proliferation of fat accumulations at the site of engraftment. B- and A-cell staining and distribution on ICC appeared normal after 12 months. Mycophenolate mofetil (MMF) together with cyclosporine (CSA) was selected to suppress rejection of foetal rat pancreatic allografts in a strong responder allogeneic model (WAG --> Sprague-Dawley). MMF, a novel immunosuppressive agent that selectively inhibits de novo purine synthesis, was administered in combination with subtherapeutic doses of CSA (2 mg/kg/day) to prevent rejection after allogeneic foetal rat pancreatic transplantation. Although CSA monotherapy in this model can partially suppress rejection, the combination of CSA and MMF results in significant inhibition of acute allograft rejection and mononuclear cellular (MNC) infiltration as assessed by sequential histology post-operatively. Although the follow-up period of allografts was restricted to 30 days of treatment, histology showed low graft infiltrate scores (1.2+) and preservation of islets and immunocytochemical staining. The results in this animal transplantation model confirm that sub-therapeutic doses of MMF and CSA therapy are effective in preventing acute rejection of foetal rat pancreatic allografts in the short-term, thus allowing preservation of vital endocrine components of the foetal pancreas such as islets.

Animals↗
PubMed1998

Underrecognition and undertreatment of asthma in Cape Town primary school children.

BACKGROUND: In view of the high local prevalence of asthma, the extent of recognition and appropriate management of childhood asthma was studied in a large suburban area of Cape Town. DESIGN: Cross-sectional study based on random community sample of schools. METHOD: 1,955 parents of sub B pupils from 16 schools completed a questionnaire, followed by: (i) an interview of the parents of 348 symptomatic children; and (ii) bronchial responsiveness testing on 254 children. The final case group consisted of 242 children with reported asthma or multiple asthma symptoms on both questionnaires. Children in whom asthma was acknowledged were compared with those in whom it was not. RESULTS: Overall, any past or current ('ever') asthma was acknowledged by respondents in only 53% of the children, and current asthma in only 37.1%. While most children had received treatment in the previous 12 months, 66.1% of the recognised group were on current treatment (23.2% on daily treatment), compared with 37% of the unrecognised group (3% daily). Salbutamol and theophylline syrups were the most common types of medication, while inhalers and anti-inflammatory medications were underused. Only a minority of parents reported the child ever having used a peak flow meter, or volunteered knowledge of preventive measures. Current treatment, and to a lesser degree recognition of asthma by parents, were more common among children on medical aid and of higher socio-economic status. CONCLUSIONS: These findings suggest that ways need to be found: (i) to increase the use of current asthma treatment guidelines by practitioners; (ii) to provide access to comprehensive care by children not on medical aid; and (iii) to improve education of parents in home management measures such as severity assessment and avoidance of smoking, allergen and dietary triggers.

Asthma↗
PubMed1995

A sociological analysis of the extent and influence of professional socialization on the development of a nursing identity among nursing students at two universities in Brisbane, Australia.

Professions make extraordinary demands on its practitioners. Professionals are required to master substantive theory and technical skills. They also develop their own unique subcultures, demanding specific normative standards from their members, which are symbolized by professional ethical codes. In the health professions, ethical codes include strong altruistic elements. Professional normative standards are learnt on a formal level (for example, at a university) and informal level (during the process of professional socialization and contact with the peer group, as well as informal sanctions). The transformation process of a novice to a professional is essentially an acculturation process during which the values, norms and symbols of the profession are internalized. Acculturation can be so strong that it may cause personality transformation, which the French refer to as 'deformation professionelle', usually displayed by stereotypes, which are almost always exemplified by members of professions as ideal professionals, those who have internalized the profession's culture completely. The question is, what is the extent of normative standards and professional characteristics that nursing students are exposed to during professional socialization, and to what extent are these standards and characteristics internalized so that a nursing 'deformation professionelle' develops? A reliable Likert-type measurement scale was developed to measure this phenomenon. One of the most important findings of this study was that students at both universities are highly professionally socialized.

Acculturation↗
PubMed1989

Seminal carnitine, epididymal function and spermatozoal motility.

The carnitine content of semen from azoospermic subjects and subjects with either impaired motility or forward progression is reported. Within the azoospermic group, the values were not significantly different between those with testicular failure or obstruction. The patients with impaired motility (less than 40%) or impaired forward progression (less than 3) had a lower mean seminal carnitine content than those with good motility and forward progression (P less than 0.05). Seminal carnitine concentration was not an index of epididymal patency and could not be regarded as useful for locating the level of obstruction in the epididymis. Since carnitine plays an important role in the maturation process when sperm acquire motility, it would seem that seminal carnitine might be an indicator of epididymal dysfunction.

Carnitine↗
PubMed1986

[Stress!].

Explore the source record for details and available documents.

Adaptation, Psychological↗
PubMedDate not supplied

Impaired epididymal function in patients with detached ciliary tufts in semen: a preliminary report.

Low spermatozoal ATP concentration in the presence of high alpha-glucosidase activity may indicate efficient epididymal function. It was suggested that detached ciliary tufts (DCTs) originated from the epididymis. We compared the spermatozoal ATP concentration and alpha-glucosidase activity in semen of patients with DCTs to that of a control group. Higher ATP concentration and lower alpha-glucosidase activity were found in patients with DCTs in their semen compared to the control group. These results might probably point out impaired epididymal function and further support the proposed epididymal origin of these tufts.

Adenosine Triphosphate↗
PubMedDate not supplied

The presence of alpha-glucosidase, glycerophosphocholine and carnitine in the epididymis and ejaculate of the vervet monkey (Cercopithecus aethiops) and the Chacma baboon (Papio ursinus).

The epididymis is the site of posttesticular sperm maturation in the male genital tract. Studies on human epididymides are hampered by the practical inaccessibility of epididymides of healthy men in their reproductive years. The limited use of laboratory animals therefore seems unavoidable. The objective was to establish baseline values of the epididymal markers alpha-glucosidase, glycerophosphocholine (GPC) and carnitine in the lumen of the caput, corpus and cauda epididymidis and in the ejaculate of adult male Chacma baboons and vervet monkeys. In both primates, alpha-glucosidase was found throughout the epididymis and in the ejaculate; values did not vary significantly. In monkeys, the highest concentration of GPC was found in the cauda epididymidis, but smaller amounts were found in the other regions and the ejaculate. In baboons, GPC was absent from the caput, but present in the other regions, including the ejaculate. Carnitine concentrations increased significantly from the caput to the cauda in monkeys and from the caput to the corpus in baboons. With this study, the relative concentration ranges in which these markers are present in the epididymides of these primates have been established. In future studies, changes in concentrations of these substances would probably indicate changes in epididymal function.

Animals↗
PubMedDate not supplied

Effect of rotation on the generation of reactive oxygen species in human semen.

Rotation of semen after liquefaction is a standard procedure in an Andrology laboratory. During rotation under aerobic conditions the semen is exposed to oxygen. Oxygen toxicity induces lipid peroxidation which is responsible for the loss of sperm function. The generation of reactive oxygen species was significantly increased after rotation. This may have a detrimental effect on sperm function during assisted reproduction.

Humans↗
PubMedDate not supplied

alpha-Glucosidase, sperm ATP concentrations, and epididymal function.

It has been suggested that alpha-glucosidase may be a marker of epididymal patency and function. Spermatozoal ATP concentrations decrease during passage through the epididymis, indicating efficient maturation. We correlated sperm motility with seminal plasma alpha-glucosidase activity and spermatozoal ATP. The sperm motility correlation with alpha-glucosidase activity was significantly positive, and the sperm motility correlation with spermatozoal ATP was significantly negative. It appears that high-alpha-glucosidase activity and low-spermatozoal ATP were present in semen with good sperm motility and could possibly indicate efficient epididymal function.

Adenosine Triphosphate↗
PubMedDate not supplied

High seminal sialic acid concentrations in patients with severe teratozoospermia.

Seminal plasma and sperm-bound sialic acid (SA) concentrations were evaluated in patients with severe teratozoospermia (less than 5% morphologically normal sperm) and correlated with values of a control group with greater than 20% morphologically normal sperm. The SA concentrations both in seminal plasma and on sperm were significantly higher in teratozoospermia, but the ratio of sperm-bound SA to seminal plasma SA remained virtually the same. The causes and consequences of high SA in these patients need further study.

Humans↗