A genetic analysis of adult plant resistance to stripe rust in the wheat cultivar Kariega.

The wheat cultivar Kariega expresses complete adult plant resistance to stripe rust in South Africa. The aim of this investigation was to determine the extent and nature of variability in stripe rust resistance in a population of 150 doubled haploid lines generated from a cross between Kariega and the susceptible cultivar Avocet S. Analysis of field data for adult plant stripe rust resistance identified two major QTLs and two minor QTLs in the resistant cultivar Kariega. The two major QTLs were located on chromosomes 7D ( QYr.sgi-7D) and 2B ( QYr.sgi-2B.1), contributing 29% and 30% to the phenotypic variance, respectively. QYr.sgi-2B.1 is primarily associated with a chlorotic and/or necrotic response, unlike QYr.sgi-7D, which is believed to be the adult plant resistance gene Yr18. These two QTLs for adult plant resistance in Kariega appear to represent different forms of resistance, where QYr.sgi-7D may represent potentially more durable resistance than QYr.sgi-2B.1. Mixture model analysis of the field leaf infection scores suggested a genetic model involving two independent genes combining in a classical, epistatic manner. The results of the QTL analysis demonstrate its higher resolution power compared to the mixture model analysis by detecting the presence of minor QTLs.

Single nucleotide polymorphisms of the protoporphyrinogen oxidase gene: inter-population heterogeneity of allelic variation.

Five single nucleotide polymorphisms (SNPs) in the protoporphyrinogen oxidase gene (PPOX) were used for inter-population comparisons of six South African populations and two non-South African Caucasian populations. Novel polymorphisms identified in the promoter region and exon 11 of the PPOX gene, as well as three known variants in exon 1 and intron 2, were analysed using single-strand conformation polymorphism (SSCP) and restriction enzyme analyses. Significant population differences were found for four of the five polymorphisms analysed. A G-to-A transition was found at nucleotide position -1081 and is the first polymorphism to be identified in the 5' promoter region of the gene. A novel A-to-C substitution at nucleotide position 3880 in exon 11 was not detected in subjects of European descent. This study represents the first inter-population comparison of allelic variation at the PPOX locus. The significant differences observed between populations demonstrate the importance of population considerations when marker association studies are performed at this locus.

Mapping of the variegate porphyria (VP) gene: contradictory evidence for linkage between VP and microsatellite markers at chromosome 14q32.

The gene for variegate porphyria (VP), an autosomal dominant disease with a high prevalance in South Africa, evidently due to a founder effect, was previously mapped to chromosome 14q32. In the current study this localization was evaluated by linkage and haplotype analyses using microsatellite markers spanning a region of more than 20 cM on chromosome 14q32. In many recent studies linkage disequilibrium between disease and marker loci has been utilized to map genes in founder populations, but we could not find any association between VP and the markers used in this study. Our data suggest that the allocation of VP to chromosome 14q32 may be incorrect.

Twenty year experience with familial polyposis coli in Cape Town.

Forty-nine patients undergoing surgery for familial polyposis coli (FPC) over a twenty year period are presented. Forty-three patients underwent total colectomy with ileorectal anastomosis (TC + IRA) and five patients subsequently developed a rectal carcinoma. The incidence of rectal carcinoma following TC + IRA appears to increase with time. There were significant postoperative complications secondary to adhesive obstruction and desmoid tumour recurrence. Upper gastrointestinal pathology has been detected by endoscopy in only one of nine patients, but the importance of upper gastrointestinal pathology is now appreciated. The problem of screening a widely distributed and closely knit community has been considerable. TC + IRA remains the operation of choice for the majority of patients with FPC, but a total colectomy with ileal reservoir and ileo-anal anastomosis is appropriate in some cases.

Axillofemoral bypass. A 2-decade experience reviewed.

A retrospective study of axillofemoral bypass performed at Groote Schuur Hospital over a period of 2 decades was undertaken to analyse the results and to re-examine current criteria for patient selection. During this period 109 patients underwent surgery. The primary indication was critical ischaemia (in 88% of cases). Operative mortality was 6,4%. Graft thrombosis and sepsis were identified as the major reasons for graft failure. Overall graft patency at 3 years was 43% and at 5 years 30%. Successful graft thrombectomy improved the overall cumulative patency rate at 5 years to 43%, and patient survival in the same period was 56%. Modern advances in the assessment of anaesthetic risk together with improved postoperative intensive care have allowed more patients who in the past would have been considered candidates for axillofemoral bypass to undergo direct aortic reconstruction. While the results of axillofemoral bypass are inferior to those of aortic grafts, the technique remains a valuable method of limb salvage for the poor-risk patient and a life-saving treatment for aortic graft sepsis.

The mucosal pattern of the gall bladder ("areae cholecysticae").

During endoscopic retrograde cholangiopancreatography (ERCP) the mucosal fold pattern of the gall bladder can be seen if radiographs are made before the contrast medium has mixed with the bile. These appearances are demonstrated by studies both in vivo and in vitro.

The management of anal carcinoma.

In a 20-year survey of anal carcinoma at Groote Schuur Hospital 55 cases were studied retrospectively. Patients of mixed race with anal margin carcinoma had a median age 29 years below that of Whites with anal margin carcinoma. Patients in these two groups with anal canal carcinoma had the same median age. Anal margin tumours were smaller than anal canal tumours at presentation and had a substantially better 5-year survival rate. The approach to treatment of these conditions is outlined.

The long-term effects of vagotomy and drainage, parietal cell vagotomy and H2 receptor antagonists on duodenal ulcers and gastric function and structure.

This paper presents a comparative retrospective analysis of the effects of vagotomy and drainage, parietal cell vagotomy (PVC) and maintenance H2 receptor antagonist (H2RA) therapy on ulcer recurrence rates, clinical status, gastric acid secretion, serum gastrin responses and gastric structure in the elective treatment of duodenal ulcer. The results indicate that the operations offered greater protection against recurrent ulceration, and that H2RA therapy provides some protection against recurrence while the patient is on continued treatment but does not alter the natural history of the disease when treatment is stopped. The evidence to date suggests that neither PCV nor H2RA therapy has altered the conventional indications for surgical treatment in duodenal ulceration.

The prognosis of alcohol-induced calcific pancreatitis.

A consecutive personal series of 314 patients with alcohol-induced calcific pancreatitis were admitted to a long-term follow-up study between 1959 and 1979. The patients were subdivided into four arbitrary groups according to the date of entry into study, and the mortality rate and survivor status were determined for each of these groups. Adjusted mortality rates increased progressively with the duration of follow-up, from 11% in the 1976-1979 to 73% in the 1959-1969 group. Pancreatic insufficiency dominated in patients followed up for 10 - 20 years, and pain was more prominent in the more recent follow-up groups. The survivor status in Whites was better than in Blacks, but the mortality rates were comparable. The occurrence of pain in patients who continued to drink was significantly less in the 10 - 20 year follow-up group than in those followed up for a shorter period of time.

Caecal angiodysplasia as a cause of chronic iron deficiency anaemia: a case report.

Angiodysplasia is a common cause of large-bowel bleeding in elderly patients, and chronic iron deficiency anaemia is usually the presenting symptom. Angiodysplasia is sometimes associated with aortic stenosis and other valvular defects. It is diagnosed arteriographically and treated by right hemicolectomy.

A comparative randomized trial of heparin versus streptokinase in the treatment of acute proximal venous thrombosis: an interim report of a prospective trial.

A controlled, prospective study comparing streptokinase and heparin treatment has been completed in 51 patients presenting with acute proximal venous thrombosis of less than 8 days' clinical duration. Patients were studied by means of pre-treatment, post-treatment, 3- and 12-monthly phlebography and pulmonary perfusion scanning and were followed up at 3-monthly intervals. Of the 26 patients randomized to receive streptokinase, therapy was stopped in 3 because of complications. Phlebography 5 days after starting treatment showed 80--100 per cent lysis in 17 of the 23 patients who completed the course of streptokinase. Two patients later developed partial rethrombosis. One patient developed an asymptomatic pulmonary embolus during treatment. During follow-up (mean 19 months) only 1 of the 17 patients with 80--100 per cent lysis developed postphlebitic symptoms, 3 patients died of unrelated causes and 1 patient was lost to follow-up. In patients randomized to heparin therapy no significant lysis was achieved in any of the 25 patients and only 2 of these patients were found to have asymptomatic legs on follow-up. Two patients in this group died and autopsy confirmed massive pulmonary embolus during treatment. These data suggest that streptokinase is superior to heparin in the treatment of acute proximal venous thrombosis of less than 1 week's clinical duration especially if the thrombus is largely non-occlusive. It must be stressed that in order to avoid the bleeding complications of thrombolytic therapy, streptokinase must not be used within 10 days of major surgery, or even longer after vascular, neurosurgical or eye operations.

Liver tumours and the contraceptive pill: Controversies in aetiology, diagnosis and management.

Six female patients seen at Groote Schuur Hospital between 1973 and 1977, with the types of liver lesion that have been linked aetiologically with the contraceptive pill, are described. Four had focal nodular hyperplasia (1 with spontaneous rupture), and 1 patient had a hepatocellular carcinoma. The sixth patient had spontaneous rupture of the liver but no tumour was demonstrated. Based on this experience and a review of the literature, controversies in aetiology, diagnosis and managment are presented. A defined management policy is proposed for the benign lesions, a less aggressive approach being advocated for focal nodular hyperplasia than for hepatic adenoma.