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Biomedical subjects

M B Taylor

Publications and source records attributed to M B Taylor.

At least 19 recordsLinked to original sources
PubMed2006

Identification of viral agents causing diarrhea among children in the Eastern Center of Tunisia.

Viral diarrhea remains a major cause of childhood morbidity and mortality worldwide. In Tunisia, no comprehensive studies of all viral agents related to diarrhea in children have yet been conducted. The present study was performed to investigate the role of enteric viruses in acute diarrhea in the country. Six hundred thirty-eight stool samples were collected from children under 5 years of age seeking medical care for acute diarrhea between October 2003 and September 2005 in hospitals from the Eastern-Center Tunisia. All samples were tested for rotavirus, astrovirus, and adenovirus using commercial antigen enzyme immunoassays (EIAs). Positive samples for rotavirus and astrovirus were confirmed by an "in-house" reverse transcriptase-polymerase chain reaction (RT-PCR). Samples positive for adenovirus antigen were subjected to further EIA screening for species F enteric adenovirus types 40 and 41. At least one viral agent was found in 30% of the specimens. The frequency of rotavirus, astrovirus, and adenovirus was 20%, 7%, and 6%, respectively. Of the stool samples containing adenovirus, 57% (20/35) were found to be positive for species F adenovirus types 40/41. Dual infections were found in 9% (17/191) of the positive samples. Enteric viruses appear to play an important role in pediatric diarrhea in Tunisia. The introduction of affordable viral diagnosis in pediatric hospitals will improve patient care by reducing the unnecessary use of antibiotics.

Acute Disease↗
PubMed2006

Molecular epidemiology of group A rotaviruses in water sources and selected raw vegetables in southern Africa.

Group A rotaviruses (RVs) are the most important cause of acute viral gastroenteritis in infants and young children. In this study raw and treated drinking water supplies at plants in two geographic areas, as well as selected irrigation water and corresponding raw vegetables in three regions of southern Africa, were screened for the presence of RVs using molecular techniques. Group A RVs were detected in 11.8% of partially treated and 1.7% of finally treated drinking water samples and in 14% of irrigation water samples and 1.7% of corresponding raw vegetable samples. Type-specific reverse transcriptase-PCR and sequence analysis revealed the presence of multiple types (G1, G2, G8, and G9) in irrigation water and single types (G1 or G3) in raw and treated drinking water. Group A RVs detected in all samples consisted of mixed P types (P[4], P[6], P[8], and P[9]), with P[6] predominating. The detection of types G8, G9, and P[6] reflects the emergence of these types in clinical infections. The similarity of environmental types to those in patients with clinical RV infections confirms the value of wastewater screening as a tool for assessing RVs circulating in communities, with the benefit of detecting types that cause both clinical and subclinical infections. The results provide new information on RV types in water and related environments and identify the potential risk of waterborne transmission. In addition, the presence of RVs in drinking water underlines shortcomings in quality specifications. These data provide valuable information regarding the prevalence of RVs in environmental sources, with important implications for vaccine development.

Agriculture↗
PubMed2006

Response evaluation in gastrointestinal stromal tumours treated with imatinib: misdiagnosis of disease progression on CT due to cystic change in liver metastases.

Imatinib is a highly effective treatment for patients with metastatic gastrointestinal stromal tumours (GIST). In most instances, response to imatinib treatment is assessed with CT. We present two cases where CT demonstrated the appearance of new low density liver lesions after 8-12 weeks of imatinib treatment. While this finding is consistent with progressive disease due to new lesions appearing at a previously uninvolved site, we hypothesise that the appearance of new liver lesions is in fact due to cystic change within previously occult, solid metastases. These untreated solid metastases were not visible on conventional portal phase CT due to their small size and vascular nature. Our hypothesis is supported by the observation that extrahepatic sites of disease had reduced in size over the same period of imatinib treatment and by the subsequent disease outcomes of these two cases. One patient, who continued imatinib because of significant symptomatic improvement despite the CT findings, remained stable on the same dose of imatinib for 18 months. The other patient, whose disease progressed when imatinib was withdrawn, had a dramatic response to treatment when imatinib was restarted at the same dose 2 years later. It is important that radiologists and oncologists who are involved in the management of GIST recognize that the appearance of new, low-density liver lesions on CT may represent a response to treatment. This finding must be correlated with symptomatic response and with tumour sites outside the liver before erroneously withdrawing effective imatinib treatment.

Aged↗
PubMed2005

Comparison of caudal steroid epidural with targeted steroid placement during spinal endoscopy for chronic sciatica: a prospective, randomized, double-blind trial.

BACKGROUND: Chronic sciatica can be managed by caudal steroid epidural or by targeted steroid placement during spinal endoscopy. Spinal endoscopy is a new unproven procedure. We aimed to compare the two pain management techniques and to investigate whether the site of steroid placement within the epidural space was significant. METHODS: We randomized 60 patients with a 6-18 months history of sciatica to either targeted epidural local anaesthetic and steroid placement with a spinal endoscope or caudal epidural local anaesthetic and steroid treatment. Pre-treatment and 6-week, 3-month, and 6-month SF-MPQ and HAD scores were recorded. RESULTS: No significant differences were found between the groups for any of the measures at any time. However, there were significant differences within both groups compared with pre-treatment values. For the caudal group, significant improvements were found for descriptive pain at 6 months (P=0.031), VAS at 6 weeks (P=0.036), 3 months (P=0.026), and 6 months (P=0.003), present pain intensity (PPI) at 3 months (P=0.013) and 6 months (P=0.01); anxiety at 6 weeks (P=0.008), 3 months (P=0.004), and 6 months (P=0.001) and depression at 6 months only (P=0.037). For the epiduroscopy group there were fewer significant changes. PPI was significantly reduced at 6 weeks (P=0.004) and at 6 months (P=0.02). Anxiety was reduced at 6 months only (P=0.03). CONCLUSION: The targeted placement of epidural steroid onto the affected nerve root causing sciatica does not significantly reduce pain intensity and anxiety and depression compared with untargeted caudal epidural steroid injection. When analysed individually, both techniques benefited patients.

Adult↗
PubMed2005

The evolution of teaching and learning medical microbiology and infectious diseases at NUS.

Infectious diseases were rife during the early years of the Singapore Medical College, which was established in 1905. The current Department of Microbiology in the National University of Singapore (NUS) has its historical roots in the Departments of Bacteriology and Parasitology, which were established in 1925 and 1950 respectively. With the achievements since its inception, and with its present research focus on Infectious Diseases, Immunology, Applied and Environmental Microbiology, it is poised to face the microbiological challenges of the 21st century. Over the decades, the structure of the medical microbiology course in NUS has modernised, culminating in the current emphasis on its practical utility in clinical practice. Coordinated by the Department of Microbiology, the Microbiology and Infectious Diseases module and the Immunology module both adopt integrated multidisciplinary approaches that aim to introduce students to the language and fundamental concepts in microbiology, infectious diseases and immunology.

Communicable Diseases↗
PubMed2004

Application of a molecular method for the detection of group A rotaviruses in raw and treated water.

Group A human rotaviruses (HRVs) are the most important aetiological agents of acute viral gastroenteritis in infants and young children in both developing and industrialised countries. Rotaviruses are resistant to many chemical disinfectants and reportedly survive well in treated tapwater and sewage. In this study a group A specific reverse transcriptase-polymerase chain reaction (RT-PCR) followed by a nested-PCR was applied for the detection of HRVs in raw and treated drinking-water samples drawn at a water reclamation plant. For a period of two years (July 2000 to June 2002), borehole, raw and treated drinking-water samples were collected weekly. Viruses were recovered from the water samples using a glass wool adsorption-elution technique followed by secondary concentration using precipitation with polyethylene glycol. In the first year of the study group A HRVs were detected in 11% sewage samples, 8% partially treated waters and 5% final treated drinking waters. The results of the second year of the study showed the presence of group A HRVs in 11% sewage and untreated surface water samples, 15% partially treated water and 6.5% final treated drinking waters. No HRVs were detected in the water samples from the boreholes. The presence of group A HRVs in treated drinking-water samples suggested that this water could be a potential source of infection to consumers. The data also implied that either the water treatment did not remove HRVs or the treated water was contaminated post-treatment.

DNA, Viral↗
PubMed2003

What is true community-acquired urinary tract infection? Comparison of pathogens identified in urine from routine outpatient specimens and from community clinics in a prospective study.

In order to identify the true nature of community-acquired urinary tract infections, the uropathogens isolated from 100 patients with urinary tract infection included in a prospective study conducted in community clinics were compared to 244 isolates from outpatient urine specimens routinely submitted to the laboratory. Significant differences in both the spectrum of bacteria and their antibiograms were found between the two groups. Laboratory data analysis of uropathogens from outpatient urine specimens may not reflect the true bacteriology of urinary tract infections acquired in the community. Hence, surveys based on laboratory data alone may overestimate resistance rates, leading to misinformed choices being made when treatment is empirical.

Anti-Bacterial Agents↗
PubMed2003

Staging of advanced cervical carcinoma using MRI-predictors of outcome after radical radiotherapy.

AIM: To assess the prognostic significance of imaging findings used in magnetic resonance imaging (MRI) staging of cervical carcinoma by correlation with survival after radiotherapy. MATERIALS AND METHODS: MRI examinations of 99 cervical carcinoma patients were reviewed. Tumour involvement of pelvic structures was assessed. Lymph node sites, short axis diameters and signal characteristics were recorded. MRI staging was compared with clinical [International Federation of Gynaecology and Obstetrics (FIGO)] staging. Univariate analysis was performed for MRI stage, clinical stage, nodal status and pelvic structure involvement against disease-specific (DSS) and disease-free survival (DFS). RESULTS: MRI staging correlated with DSS (p=0.006) and DFS (p=0.007) but clinical staging did not. Pelvic nodes > or = 10 mm and juxtaregional or distant nodes > or = 8 mm short axis were most strongly associated with survival (p=0.014, p=0.011 and p=0.001, respectively, for association with DSS). Tumour involvement of pelvic bowel loops, pelvic sidewall and bladder mucosa were significantly associated with poor DSS and DFS (p<0.05). Tumour dimensions and bladder muscle involvement alone were not associated with poor survival. CONCLUSION: MRI staging is a better predictor of survival than clinical staging in patients receiving radiotherapy for cervical carcinoma. MRI assessment of lymph node enlargement and tumour involvement of pelvic structures gives valuable prognostic information.

Adult↗
PubMed2003

Molecular characterization of astroviruses by reverse transcriptase PCR and sequence analysis: comparison of clinical and environmental isolates from South Africa.

A comparative analysis was performed with 25 isolates of astroviruses (AstVs) detected in sewage sources and 22 concurrently identified clinical AstV isolates from the Tshwane (Pretoria) Metropolitan Area in South Africa. The samples and specimens were screened for AstVs by using an enzyme immunoassay and/or a reverse transcriptase PCR (RT-PCR) for the highly conserved untranslated region (3' end) of the genome. The RT-PCR results were confirmed by oligonucleotide probe dot blot hybridization. Viable viruses were propagated in cell cultures for amplification when a minimal specimen was available or indeterminate sequences were obtained. AstV strains were characterized by RT-PCR and partial sequence analysis of the capsid region. The presence of multiple human AstV (HAstV) types in a single sewage sample complicated identification of individual strains, and additional type-specific RT-PCR and sequence analyses of the capsid region were required for characterization. Amplification and characterization of one genotype from a sample, therefore, did not preclude the possibility that a sample harbored additional different genotypes. Genotype and sequence information obtained from AstVs in wastewater samples were compared to information obtained from AstV strains from human stools. HAstV type 1 (HAstV-1), as well as HAstV-3, -5, -6, and -8, were identified among the clinical isolates, and HAstV-1, -2, -3, -4, -5, -7, and -8 were identified among the environmental samples. Phylogenetic analysis demonstrated that HAstV-1, -3, -5, and -8, which were present in human stool and sewage samples, clustered together, indicating that these viruses are closely related. The concurrent presence of identical HAstV strains in wastewater samples and in hospitalized patients suggests that AstVs present in the environment pose a potential risk to communities in which fecally contaminated water is used for recreational and domestic purposes.

Astroviridae Infections↗
PubMed2001

Characterisation of a South African human astrovirus as type 8 by antigenic and genetic analyses.

Human astroviruses (HAstV) can, on the basis of immunoassays using type-specific rabbit antisera, be classified into eight serotypes that correlate with genotypes. Very few isolates of HAstV type 8 have been described and there is a paucity of data available with regard to the antigenic and genetic relationships between HAstV type 8 (HAstV-8) and HAstV types 1 (HAstV-1) to 7 (HAstV-7). A wild-type HAstV from a South African paediatric patient with diarrhoea was analysed antigenically, by immune electron microscopy and enzyme immunoassay, and genetically in selected regions of the ORF1a, ORF1b and ORF2 and characterised as a HAstV-8. This HAstV-8 strain exhibited greatest homology with HAstV-4 in the 5' end of the capsid gene and ORF1a and 1b, and greatest homology with HAstV-5 in the 3' end of the capsid region. This study confirms, by both antigenic and genetic analyses, that HAstV-8 represents a distinct antigenic and genotype and is the first report of a HAstV-8 from a hospitalised paediatric patient with diarrhoea in southern Africa.

Amino Acid Sequence↗
PubMed2001

Magnetic resonance imaging in the diagnosis and management of choroid plexus carcinoma in children.

BACKGROUND: Choroid plexus carcinoma (CPC) is a rare tumour occurring in childhood. The MRI features are not well described. OBJECTIVE: To characterise the MRI features of CPC in children and to describe the role of MRI in post-surgical management. MATERIALS AND METHODS: The pre- and post-operative MRI examinations of five children with histologically proven CPC treated at this hospital were reviewed. RESULTS: The tumour was supratentorial in two patients and infratentorial in three patients. Pre-operative MRI showed heterogeneous enhancing tumours with irregular margins, parenchymal invasion and surrounding oedema. Cystic change within the tumour was present in all patients. Curvilinear signal voids were seen in two patients and punctate signal voids in one. All patients had hydrocephalus. In one patient a fourth-ventricular metastasis was present at diagnosis. In all cases, surgical resection was incomplete. Follow-up found long-term survival in one patient who had been treated with chemotherapy and further surgery. CONCLUSION: The MRI characteristics of CPC are nonspecific, but intraventricular location with tumour heterogeneity, parenchymal invasion and oedema may be useful features in diagnosis. MRI is valuable in the initial diagnosis, surgical planning and follow-up of children with these rare tumours.

Brain↗
PubMed2001

The occurrence of hepatitis A and astroviruses in selected river and dam waters in South Africa.

Over a period of one year (June 1997-May 1998) samples of surface waters, used for domestic and recreational purposes, were collected weekly from the same sites on the Klip River and Vaal Dam, Gauteng, South Africa. Sensitive and specific reverse transcriptase-polymerase chain reaction-oligonucleotide probe assays were used to detect HAV and HAstV RNA in concentrates of the water and infectious virus in cell cultures infected with the water concentrates. HAV was detected in 18 (35.3%) of the river and 19 (37.3%) of the dam water samples, often in association with the RNA from other enteric viruses. HAstV was detected less frequently and was present in 11 (21.6%) of the river and 3 (5.9%) of the dam water samples. A seasonal pattern was noted for HAV but not for HAstV. Cell culture amplification in a variety of carefully selected cell culture systems enhanced the detection of both viruses. Infectious viruses were detected in dam water samples where microbiological indicators of faecal pollution were absent or within acceptable limits. The presence of these viruses in the dam and river water could pose a potential health risk for people using these waters for domestic or recreational purposes.

Adult↗
PubMed2001

The effect of radiotherapy treatment changes on sites of relapse in stage I testicular seminoma.

AIM: To evaluate relapse patterns in stage I testicular seminoma related to changes in radiotherapy practice. METHOD: Four hundred and six patients with stage I testicular seminoma were treated with adjuvant radiotherapy following orchidectomy: 338 patients received para-aortic radiotherapy only and 68 patients with added risk factors had radiotherapy extended to include the pelvis. Computed tomograms of relapsed patients were reviewed and sites of relapse were documented with correlation to the radiotherapy field. RESULTS: Thirteen relapses were identified; 10 occurring in the para-aortic radiotherapy group (3.0% relapse rate) and three in the extended radiotherapy field group (4.4% relapse rate). Sites of relapse were; five pelvis, three mediastinum, one lung, one scapula, one scrotum, while one patient had multiple relapse sites including the pelvis and one had a tumour marker relapse with no site identified. All the pelvic relapses occurred in the para-aortic radiotherapy group. CONCLUSION: Pelvic relapse only occurred when radiotherapy had been confined to the para-aortic region. Since para-aortic radiotherapy achieves equivalent outcome to wider field radiotherapy with reduced toxicity, it is likely to become standard practice in stage I seminoma and pelvic relapses will therefore increase in frequency. It is therefore important to include pelvic imaging when relapse is suspected.

Adult↗
PubMed2001

Alternatives for women through menopause.

Today, 42% of Americans use alternative nonprescription therapies to treat medical conditions; 46% of nonprescription alternative use for principal medical conditions is done without consulting either a medical doctor or a nonphysician practitioner of alternative therapy. Many nontraditional alternatives are used to treat the hot flashes and somatic complaints of menopause, for which options such as hormone replacement therapy and other prescription and over-the-counter drugs are also available. To date, no one agent treats all menopausal symptoms as effectively as estrogen. Selective estrogen-receptor modulators can help prevent osteoporosis but do not relieve menopausal symptoms. However, some women are unwilling or unable to take hormone replacement therapy, and some decide to discontinue therapy. Evidence supporting the use of some nonprescription alternatives for conditions related to menopause is limited. Patients need to be aware of the potential for drug interactions when these alternative therapies are used concomitantly with prescription drugs. The current evidence to support use of hormone replacement therapy, selective estrogen-receptor modulators, and nontraditional alternatives is reviewed here.

Female↗
PubMed2001

Methemoglobinemia: Toxicity of inhaled nitric oxide therapy.

Elevation in methemoglobin is a known toxicity of inhaled nitric oxide (NO) therapy. This article describes two significant episodes of methemoglobinemia. These cases illustrate the probable cause and the treatment strategies for the potential for delivery of high concentrations of NO, resulting in methemoglobinemia with moderate and even low-dose delivered NO. We propose mechanisms for this occurrence and means of prevention.

Journal Article↗
PubMed2001

New methods for the detection of viruses: call for review of drinking water quality guidelines.

Drinking water supplies which meet international recommendations for source, treatment and disinfection were analysed. Viruses recovered from 100 L-1,000 L volumes by in-line glass wool filters were inoculated in parallel into four cell culture systems. Cell culture inoculation was used to isolate cytopathogenic viruses, amplify the nucleic acid of non-cytopathogenic viruses and confirm viability of viruses. Over a period of two years, viruses were detected in 23% of 413 drinking water samples and 73% of 224 raw water samples. Cytopathogenic viruses were detected in 6% raw water samples but not in any treated drinking water supplies. Enteroviruses were detected in 17% drinking water samples, adenoviruses in 4% and hepatitis A virus in 3%. In addition to these viruses, astro- and rotaviruses were detected in raw water. All drinking water supplies had heterotrophic plate counts of < 100/mL, total and faecal coliform counts of 0/100 mL and negative results in qualitative presence-absence tests for somatic and F-RNA coliphages (500 mL samples). These results call for a revision of water quality guidelines based on indicator organisms and vague reference to the absence of viruses.

Cell Culture Techniques↗