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Biomedical subjects

D F du Toit

Publications and source records attributed to D F du Toit.

At least 19 recordsLinked to original sources
PubMed1991

Intra-ocular concentration-time relationships of subconjunctivally administered gentamicin.

Eighty-nine patients scheduled for cataract removal or lens implantation were divided randomly into three groups. Each received 5, 10 or 20 mg gentamicin subconjunctivally at times varying between 0.2 and 19 hours pre-operatively. At surgery a sample of aqueous humour was obtained and analysed for gentamicin concentration. The data for each group were subjected to non-linear regression analysis to fit an open one-compartment pharmacokinetic model with first-order kinetics. A statistically acceptable fit was obtained. The average values of the pharmacokinetic parameters obtained from the single doses were used to simulate multiple-dose kinetics. The average target intra-ocular gentamicin concentrations and dosage interval were specified in the computer program, which subsequently allowed calculation of the dose required. This allowed the construction of a simple linear nomogram that can be used to read off the dose needed for handling specific clinical situations.

Aged↗
PubMed1988

Pancreatic transplantation in a patient with severe insulin resistance. A case report.

A 22-year-old white woman with insulin-dependent diabetes mellitus of 20 years' duration and advanced secondary complications underwent pancreatic transplantation for severe insulin resistance and rapidly progressive nephropathy. Resistance to all forms and strengths of subcutaneously administered insulin had necessitated almost permanent hospitalisation for the previous 10 years. Short-term improvement of the endocrine and metabolic status was achieved by initial segmental and subsequent whole pancreatic transplantation.

Adult↗
PubMed1987

Splenic rupture caused by a cricket ball. A case report.

A 14-year-old boy presented with a ruptured spleen after being injured by a cricket ball during a match. A typical picture of splenic rupture with intra-abdominal haemorrhage was evident on admission to hospital. At emergency laparotomy splenorrhaphy was not feasible because of a deep hilar laceration and splenectomy was performed.

Adolescent↗
PubMed1987

Gastric haemorrhage in a patient with neurofibromatosis. A case report.

A 54-year-old woman with upper gastro-intestinal haemorrhage, neurofibromatosis and an underlying schwannoma of the stomach is presented. Gastroscopy and barium meal examination revealed the presence of a submucosal gastric tumour with overlying ulceration. A Billroth II gastrectomy was performed with complete excision of the tumour; histologically this was revealed as a schwannoma of undetermined biological activity.

Female↗
PubMed1987

Traumatic superior mesenteric arteriovenous fistula. A case report.

In a case of traumatic superior mesenteric arteriovenous fistula resulting from a stab wound in the abdomen clinical signs of high-output cardiac failure or portal hypertension were absent. Selective angiography was useful in confirming and locating the fistula. The patient made a good recovery after resection of the aneurysm and fistula and insertion of a prosthetic graft.

Adult↗
PubMed1987

Application of irradiation as an immunosuppressive agent.

The concept of using total lymphoid irradiation (TLI) for immunosuppression is based on the prolonged and profound immunosuppressive effects observed after TLI in the treatment of patients with Hodgkin's disease. Pre-operative TLI of allograft recipients has been shown to be immunosuppressive when used alone or together with chemical immunosuppression. Fractionated TLI and allogeneic bone marrow injections produce stable chimaerism without graft-versus-host disease in inbred mice, rats and mongrel dogs and transplantation tolerance of skin and cardiac grafts in rats. In the primate, TLI and bone marrow injection result in significant tolerance of liver and kidney allografts. In 1959 sublethal whole-body irradiation was used as an immunosuppressive agent for the first successful related-human renal allografts between non-identical twins. Despite the dangers of myelosuppression, recent clinical experience has shown TLI to be a useful immunosuppressant for organ transplantation, allowing decreased dosage of concomitant immunosuppressive drugs.

Animals↗
PubMed1987

Morphology and endocrine production of cells in the islets of Langerhans of the Chacma baboon.

Biopsies of the pancreas head, tail, and uncinate regions of 6 Chacma baboons (Papio ursinus) were processed for ultrastructural and immunocytochemical (ICC) studies using avidin-biotin peroxidase label for light microscopy (LM) and immunogold for electron microscopy (EM). Survey 0.5 micron sections of Spurrs resin embedded tissue revealed areas of suitable islets. Thin 100-nm sections were then cut and stained from the osmicated blocks for ultrastructural studies. For ICC investigations, 1 micron sections were immunolabeled for LM before areas were selected for thin sectioning for ultrastructural immunolabeling. The baboon endocrine pancreas ultrastructure was found to be similar to that of other mammals with minor differences in islet and secretory granule size and shape and in electron opacity of the secretory granule cores. Insulin glucagon, somatostatin and pancreatic polypeptide (PP) producing cells were described. A small number of cells were seen to contain both glucagon and PP and some D cells were observed to contain a few granules with both the appearance and immunoreactivity of A cell secretory granules. Statistical analysis of 100 secretory granule diameters of each of the 4 cell types in 6 baboons revealed significant differences (p less than 0.001) in size between all but those of the A and D cells. The insulin precursor subunit, C-peptide, and the glucagon precursor, glicentin, were each found together with the final hormone product in their respective secretory granules. The precursors were often located toward the periphery of the secretory granule, suggesting that the conversion of precursor to active hormone may be membrane associated. A nonrandom topographical association was observed between A and D cells, suggesting a strong functional implication.

Animals↗
PubMed1986

[Perspectives in the clinical application of pancreas transplantation in the diabetic].

Until June 1983 a total of 280 human pancreatic transplantations had been performed world-wide. Until July 1983, 57 were functioning (22%), 11% for more than 12 months. During the past 5 years a steady increase in the number of segmental transplants has been observed. In most cases simultaneous transplantation of pancreas and kidney was performed (144 cases), in 65 cases the pancreas was transplanted metachronously after kidney grafting, and in 64 cases pancreatic transplantation was performed alone. Currently, segmental or whole pancreatic transplantation is the favoured procedure. Islet transplantation has been disappointing because of the difficulty in procuring sufficient numbers of islets from an adult pancreas followed by immunological destruction of the transplanted islets. Most pancreas grafts have been procured from cadavers, but the favoured segmental technique allows living related donors to be used. After rejection the graft does not always have to be removed and exogenous insulin administration may be resumed, either permanently or until re-transplantation can be accomplished. Life-long immunosuppression is needed after transplantation and currently pancreatic allograft survival rates for cyclosporin (CSA) and azathioprine-treated patients have been similar. The longest survival of a living diabetic recipient with a functioning pancreas is 5 1/2 years. Some authors have recently claimed improvement and stabilization of impaired nerve conduction and diabetic retinopathy after pancreatic transplantation.

Diabetes Mellitus, Type 1↗
PubMed1986

The application, mechanism of action and side-effects of immunosuppressive agents in clinical transplantation.

The conventional agents (azathioprine and steroids) have been the mainstay or organ allograft immunosuppression for the past 20 years. The main drawback of the immunosuppressive agents at present in use is that they act nonspecifically with sequential general depression of the immune system. The introduction of cyclosporin, an undecapeptide of fungal origin, which selectively inhibits T-cell-dependent immuno-reaction has made a significant impact on organ allograft survival rates. Clinical application has been complicated because of renal or hepatotoxicity. Thoracic duct drainage is of historical interest but the use of antilymphocyte serum, despite its chequered history, has recently been shown to be safe and effective in cadaver kidney transplant recipients. There has also been a resurgence of interest in the use of total lymphoid irradiation as an immunosuppressive agent. The introduction of xenogenic monoclonal antibodies with anti-T-cell specificity opened a new era in clinical immunology and OKT3-PAN has emerged as a powerful major immunosuppressive agent with low toxicity.

Graft Rejection↗
PubMed1986

Congenital choledochal cyst. A case report.

A congenital choledochal cyst presented as an upper abdominal mass in a non-jaundiced woman; at laparotomy total cystectomy was performed and biliary enteric continuity re-established by a hepaticojejunostomy Roux-en-Y anastomosis.

Adult↗
PubMed1986

Budd-Chiari syndrome. A report of 3 cases.

Three patients with the Budd-Chiari syndrome are presented. This is a rare condition characterized by hepatomegaly, progressive and refractory ascites, distension of the abdominal wall veins, abdominal pain and leg oedema. These features are attributed to congestion of the liver and portal hypertension. The condition has been notoriously difficult to treat medically. Surgical measures are directed towards relieving the liver congestion and lowering pressure in the portal system by portal-systemic shunting operations. In some cases refractory ascites may be treated by peritoneovenous shunting with a Le Veen shunt. In a select group of patients orthotopic liver transplantation has proved to be worth while.

Adolescent↗
PubMed1986

Acute abdomen in a patient with situs inversus. A case report.

The case of a man with situs inversus who presented with acute abdomen is reported. Acute left-sided appendicitis was considered before operation, but at laparotomy an omental abscess of unknown aetiology was drained. The appendix, localized in the left iliac fossa, was removed but was normal on histological examination.

Abdomen, Acute↗