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Biomedical subjects

S W van der Merwe

Publications and source records attributed to S W van der Merwe.

11 recordsLinked to original sources
PubMed2006

6-Thioguanine treatment in inflammatory bowel disease: a critical appraisal by a European 6-TG working party.

Recently, the suggestion to use 6-thioguanine (6-TG) as an alternative thiopurine in patients with inflammatory bowel disease (IBD) has been discarded due to reports about possible (hepato) toxicity. During meetings arranged in Vienna and Prague in 2004, European experts applying 6-TG further on in IBD patients presented data on safety and efficacy of 6-TG. After thorough evaluation of its risk-benefit ratio, the group consented that 6-TG may still be considered as a rescue drug in stringently defined indications in IBD, albeit restricted to a clinical research setting. As a potential indication for administering 6-TG, we delineated the requirement for maintenance therapy as well as intolerance and/or resistance to aminosalicylates, azathioprine, 6-mercaptopurine, methotrexate and infliximab. Furthermore, indications are preferred in which surgery is thought to be inappropriate. The standard 6-TG dosage should not exceed 25 mg daily. Routine laboratory controls are mandatory in short intervals. Liver biopsies should be performed after 6-12 months, three years and then three-yearly accompanied by gastroduodenoscopy, to monitor for potential hepatotoxicity, including nodular regenerative hyperplasia (NRH) and veno-occlusive disease (VOD). Treatment with 6-TG must be discontinued in case of overt or histologically proven hepatotoxicity.

Antimetabolites, Antineoplastic↗
PubMed2004

Quantitation of hydroxyproline in bone by gas chromatography-mass spectrometry.

A validated gas chromatography (GC)-mass spectrometric (MS) method for the analysis of hydroxyproline in rat femur is reported. Hydroxyproline in bone hydrolysates was extracted with an anion exchange resin and the N(O)-tert-butyldimethylsilyl derivatives analyzed by GC-MS. The hydroxyproline concentration was estimated relative to pipecolic acid, 3,4-dehydroproline and n-tetracosane as internal standards. The mass-to-charge ratios (m/z) for the ions used for quantitation by single ion monitoring were 314 m/z for hydroxyproline, 198 m/z for pipecolic acid, 256 m/z for dehydroproline and 57 m/z for n-tetracosane. A coefficient of variation of 5.8% was achieved and the limit of detection was calculated to be 0.233 micromol/l bone hydrolysate.

Animals↗
PubMed2004

Distal embolization and local vessel wall ulceration after gastric variceal obliteration with N-butyl-2-cyanoacrylate: a case report and review of the literature.

Repeated endoscopic injections of N-butyl-2-cyanoacrylate mixtures into large gastric varices in a single patient led to two complications: initially, pulmonary embolism, and later local ulceration of the wall of a varix. The latter resulted in massive uncontrollable hemorrhage that ultimately led to a fatal outcome. This case report also analyzes complications reported in the literature during similar endoscopic procedures for gastric varices.

Adult↗
PubMed2003

Hepatic osteodystrophy in rats results mainly from portasystemic shunting.

BACKGROUND AND AIMS: In chronic liver disease, bone disease frequently develops. The contributions of the different features of liver disease such as parenchymal inflammation, portal hypertension, and portasystemic shunting on bone metabolism have not been systematically studied. The aim of this study was to identify the features of liver disease contributing to bone disease using rat models. METHODS: Parenchymal liver disease was induced by carbon tetrachloride administration, portal hypertension by partial portal vein ligation, and portasystemic shunting by end to side anastomosis of the portal vein to the inferior vena cava. Normal and sham operated surgical animals served as controls. Serum calcium, 25-hydroxy vitamin D (25-OH vit D), and osteocalcin levels, and urinary deoxypyridinoline excretion were analysed. Testosterone and oestradiol levels were determined in male and female rats, respectively. Interleukin 1, interleukin 6, and tumour necrosis factor alpha (TNF-alpha) were determined in serum. Bone density was measured in all groups and in addition, in the surgical groups, histomorphometry was performed on undecalcified specimens of the proximal tibia. The calcium content of the femurs, removed at termination and ashed, was determined. RESULTS: Early parenchymal disease and portal hypertension did not affect bone metabolism or body mass. Portasystemic shunting increased bone resorption, decreased bone formation, bone density, and trabecular bone volume which were commensurate with a reduction in body mass. TNF-alpha levels were elevated and testosterone levels were low in male portasystemic shunted rats. CONCLUSIONS: Portasystemic shunting in the rat adversely affects bone metabolism as part of a generalised catabolic state where high TNF-alpha and low testosterone and 25-OH vit D levels may play a role.

Absorptiometry, Photon↗
PubMed2002

Evaluation of a novel heminested PCR assay based on the phosphoglucosamine mutase gene for detection of Helicobacter pylori in saliva and dental plaque.

A novel heminested PCR protocol was developed for the specific detection of Helicobacter pylori at low copy numbers. A set of primers specific for the phosphoglucosamine mutase gene (glmM) of H. pylori produced a 765-bp fragment that was used as template for the heminested primer pair delineating a 496-bp fragment. By using agarose gel electrophoresis for detection of the heminested PCR-amplified products, amplification of H. pylori genomic DNA was achieved at concentrations as low as 0.1 pg, equivalent to 5 x 10(2) bacteria. A study was subsequently undertaken to evaluate the heminested PCR for detection of H. pylori in dental plaque and saliva. Specimens collected from 58 individuals were cultured, and PCR was subsequently performed on the oral cultures. Identification of H. pylori in the same series of saliva and dental plaque specimens was carried out with PCR using a primer pair specific for the H. pylori urease B gene and by the heminested PCR assay. The identity of the amplified products was confirmed by DNA sequencing. Our results demonstrate that the heminested PCR assay was specific for detection of H. pylori, yielding no false-positive results, and that H. pylori had a low prevalence (approximately 3%) in specimens obtained from the oral cavity.

DNA Primers↗
PubMed2000

Hepatic osteodystrophy: the influence of liver disease and portal hypertension on cytokine activation.

Chronic liver disease is frequently complicated by bone disease. The mechanisms leading to bone-loss are unknown but are probably not related to abnormal vitamin D metabolism. The effects of portal hypertension and porto-systemic shunting on bone-loss have not been studied. It is postulated that liver disease, or the complications of liver disease (portal hypertension or porto-systemic shunting), might be responsible for the activation of cytokines. It is further postulated that these cytokines might be the final common pathway leading to bone-loss in both parenchymal and cholestatic liver disorders by modifying osteoblast or osteoclast function.

Cytokines↗
PubMed1991

An adaptation of the Moyers mixed dentition space analysis for a Western Cape Caucasian population.

200 dental plaster casts of Western Cape Caucasoid subjects, all of whom were under the age of 21 years, were used in this study. Mesio-distal measurements (MD lengths) were obtained of all the teeth, disregarding the third molars. This data was used to develop regression equations, for maxillary and for mandibular arches, to enable the prediction of the mesio-distal lengths of the canine and two premolars. The study identified the sum of the MD lengths of the permanent lower incisors as the best predictor. It appears that separate predictions for male and female are not warranted. The equations and the predicted values were compared with those of Moyers (1973 and 1988) and some significant differences were found. The Prediction Tables will be useful in analysis of the mixed dentition phase in patients from this population group.

Adolescent↗
PubMedDate not supplied

Anaerobic bacteremia and necrotizing fasciitis in a patient with Crohn's disease.

Crohn's disease is a chronic, granulomatous disease that affects the gut that is frequently treated with immunosuppressive therapy. Infectious complications are common and are usually related to the transmural nature of the inflammation, frequently manifesting as abscesses or perianal sepsis. Necrotizing fasciitis has not been reported in Crohn's disease. A case of a fatal necrotizing fasciitis in a patient with Crohn's disease after gut biopsies and corticosteroid therapy is reported.

Adult↗