PubMed Health⌕ Search

Biomedical subjects

J van der Walt

Publications and source records attributed to J van der Walt.

8 recordsLinked to original sources
PubMed2006

Allelic association of sequence variants in the herpes virus entry mediator-B gene (PVRL2) with the severity of multiple sclerosis.

Discrepant findings have been reported regarding an association of the apolipoprotein E (APOE) gene with the clinical course of multiple sclerosis (MS). To resolve these discrepancies, we examined common sequence variation in six candidate genes residing in a 380-kb genomic region surrounding and including the APOE locus for an association with MS severity. We genotyped at least three polymorphisms in each of six candidate genes in 1,540 Caucasian MS families (729 single-case and multiple-case families from the United States, 811 single-case families from the UK). By applying the quantitative transmission/disequilibrium test to a recently proposed MS severity score, the only statistically significant (P=0.003) association with MS severity was found for an intronic variant in the Herpes Virus Entry Mediator-B Gene PVRL2. Additional genotyping extended the association to a 16.6 kb block spanning intron 1 to intron 2 of the gene. Sequencing of PVRL2 failed to identify variants with an obvious functional role. In conclusion, the analysis of a very large data set suggests that genetic polymorphisms in PVRL2 may influence MS severity and supports the possibility that viral factors may contribute to the clinical course of MS, consistent with previous reports.

3' Untranslated Regions↗
PubMed1998

Detection of lymphoma in bone marrow by whole-body positron emission tomography.

Positron emission tomography (PET) is a whole-body imaging technique using 18 fluorine-fluorodeoxyglucose (FDG), whose uptake is increased in tumor cells. Published studies have shown PET to be an effective method of staging lymphoma and to be more sensitive than CT at detecting extranodal disease. The purpose of this study was to determine whether the increased marrow uptake of FDG observed in some lymphoma patients during routine staging PET scans represented marrow involvement by disease. PET scans of 50 patients with Hodgkin's (12) and non-Hodgkin's (38) lymphoma were analyzed by three independent observers and the marrow graded as normal or abnormal using a visual grading system. Unilateral iliac crest marrow aspirates and biopsies were performed on all patients. The PET scan and marrow histology agreed in 39 patients (78%), being concordant positive in 13 and concordant negative in 26 patients. In 8 patients the PET scan showed increased FDG uptake but staging biopsy was negative; in 4 of these 8 patients the PET scan showed a normal marrow background with focal FDG "hot spots" distant from the site biopsied. In 3 patients the marrow biopsy specimen was positive but the PET scan normal; 2 of these 3 patients had non-Hodgkin's lymphoma whose malignant cells did not take up FDG at lymph node or marrow disease sites. Therefore, there were only 5 patients (10%) in whom there was a difference between the PET scan and biopsy result which could not be fully explained. Visual interpretation of marrow FDG uptake during whole-body staging PET scans can correctly assess marrow disease status in a high proportion of lymphoma patients. PET has the potential to reduce the need for staging marrow biopsy.

Biopsy↗
PubMed1981

Sarcomere relaxation and ischaemic myocardial injury.

Material from hearts known to have had recent myocardial infarction and biopsies of dog hearts subjected to an experimental procedure producing ischaemic injury, were examined by polarising microscopy. A technique which depends on the relaxation of sarcomeres on ischaemic areas of myocardia was used and assessed for its value in the diagnosis of early myocardial infarction. We found no statistically significant difference in sarcomere lengths in ischaemic and control heart muscle in man. The dog study failed to show changes with a study period of up to 2 h after ligation. We do not support the suggestion that sarcomere length is a useful measurement in the demonstration of early myocardial ischaemic injury in man.

Animals↗
PubMedDate not supplied

Collecting duct carcinoma of the kidney associated with the sickle cell trait.

Collecting duct carcinoma of the kidney is a rare neoplasm that arises from the medullary collecting ducts. It has an aggressive clinical course and patients usually present with metastatic disease. Treatment approaches apart from surgery have been unrewarding. Renal medullary carcinoma is also an aggressive tumour which occurs predominantly in young, black, male patients with sickle cell trait. We describe a case of collecting duct carcinoma in a 61-year-old black female who exhibited the sickle cell trait. Histopathology revealed a high-grade tubular carcinoma with marked desmoplasia, adjacent dysplastic collecting ducts and positive immunohistochemical staining for high and low molecular weight cytokeratins and epithelial membrane antigen. The association of collecting duct carcinoma with sickle cell trait has not been previously reported. This case supports the postulate that collecting duct carcinoma and renal medullary carcinoma may be part of the same spectrum of renal malignancies.

Fatal Outcome↗