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Biomedical subjects

B V Taylor

Publications and source records attributed to B V Taylor.

18 recordsLinked to original sources
PubMed2003

Past exposure to sun, skin phenotype, and risk of multiple sclerosis: case-control study.

OBJECTIVE: To examine whether past high sun exposure is associated with a reduced risk of multiple sclerosis. DESIGN: Population based case-control study. SETTING: Tasmania, latitudes 41-3 degrees S. PARTICIPANTS: 136 cases with multiple sclerosis and 272 controls randomly drawn from the community and matched on sex and year of birth. MAIN OUTCOME MEASURE: Multiple sclerosis defined by both clinical and magnetic resonance imaging criteria. RESULTS: Higher sun exposure when aged 6-15 years (average 2-3 hours or more a day in summer during weekends and holidays) was associated with a decreased risk of multiple sclerosis (adjusted odds ratio 0.31, 95% confidence interval 0.16 to 0.59). Higher exposure in winter seemed more important than higher exposure in summer. Greater actinic damage was also independently associated with a decreased risk of multiple sclerosis (0.32, 0.11 to 0.88 for grades 4-6 disease). A dose-response relation was observed between multiple sclerosis and decreasing sun exposure when aged 6-15 years and with actinic damage. CONCLUSION: Higher sun exposure during childhood and early adolescence is associated with a reduced risk of multiple sclerosis. Insufficient ultraviolet radiation may therefore influence the development of multiple sclerosis.

Adolescent↗
PubMed2000

Cold sweats.

Explore the source record for details and available documents.

Adult↗
PubMed2000

Natural history of 46 patients with multifocal motor neuropathy with conduction block.

We studied 46 consecutive patients with multifocal motor neuropathy with conduction block (MMN-CB). Typically, asymmetric weakness and atrophy of the hands or arms developed insidiously, but spontaneous improvement (without treatment) or death from this disease did not occur and 94% remained employed. For 18 patients examined on multiple occasions using the weakness subscore of the neuropathy impairment score [NIS(W)] for a median time of 2.3 years, worsening of 1.3 points per year was observed; many patients, however, had received intensive immunomodulating therapy. Median worsening to our first evaluation (generally without treatment) was estimated at 4.2 points per year, perhaps suggesting that treatment had influenced course. Three criteria for conduction block (CB) were compared, but the least stringent was sensitive for the diagnosis. Conduction block accompanied by weakness and atrophy typically affected only motor fibers, especially of midforearm nerves, and these sites of dysfunction persisted for months or years. Neurological signs and electrodiagnostic features were consistent with CB, axonal degeneration, a variable degree of reinnervation, and segmental demyelination. Although this study did not focus on therapy, intravenous gammaglobulin and cyclophosphamide appeared to be associated with neurological improvement, which was seldom complete or sustained. Axonal degeneration and faulty regeneration may in part explain this muted response. Possibly, treatment must be earlier, more intense, or different.

Action Potentials↗
PubMed2000

Homocysteine, vitamins, and coronary artery disease. Comprehensive review of the literature.

OBJECTIVE: To summarize results of clinical trials investigating the role of homocysteine (tHcy) as a risk factor for coronary artery disease (CAD) and the role of vitamin therapy (folic acid and vitamins B6 and B12) in primary and secondary prevention of CAD. QUALITY OF EVIDENCE: MEDLINE was searched from January 1976 to January 1999 to locate cross-sectional, retrospective and prospective cohort studies and meta-analyses on CAD using the MeSH words homocysteine, folic acid, vitamins B6 and B12, and coronary artery or heart disease. MAIN MESSAGE: Elevated tHcy levels are prevalent; most retrospective and cross-sectional studies show an association with increased risk of CAD. Results from recent prospective studies are less consistent. Folic acid, alone or with vitamins B6 and B12, reduces tHcy concentrations in the blood. Results from ongoing randomized controlled trials could determine the effect of vitamins B6 and B12 and folic acid supplementation on CAD-related morbidity and mortality and could indicate whether routine supplementation with these vitamins should be advocated. Before mass screening for tHcy can be done, the tHcy assay must be standardized. CONCLUSION: The role of homocysteine and vitamins B6 and B12 in managing CAD is unclear. Routine screening is not recommended.

Clinical Trials as Topic↗
PubMed1999

Saccular aortic aneurysms.

Most vascular surgeons believe that saccular aortic aneurysms have a more ominous natural history than the typical fusiform aneurysm, although this is not documented in the literature. Expeditious repair is indicated for symptomatic saccular aneurysms, and intervention is usually advocated even when they are asymptomatic because of the general belief that their unique shape predisposes them to rupture. The objective of this report is to review the presentation and surgical management of this uncommon pathology. The records of 10 patients who underwent surgical intervention for an aortic saccular aneurysm between 1985 and 1998 were reviewed. To summarize their presentation and management, we grouped patients according to anatomic location: group A (distal arch), group B (descending thoracic aorta), group C (visceral aorta), and group D (infrarenal aorta). From analysis of these data we conclude that although saccular aortic aneurysms are rare, when present, they are most commonly found in the thoracic and suprarenal aorta. Most cases treated with surgery are symptomatic. Most thoracic and suprarenal saccular aneurysms can be repaired with a patch graft, which spares thoracic intercostals. Repair of saccular aneurysms of the distal arch are only feasible when performed with the use of hypothermic circulatory arrest. Infrarenal saccular aneurysms generally require tube graft replacement because the coexistent atherosclerosis makes patch repair difficult. Endovascular techniques may be the procedure of choice in the future.

Aged↗
PubMed1998

Effects of radiation and chemotherapy on cognitive function in patients with high-grade glioma.

PURPOSE: The effect of radiotherapy on the long-term cognitive performance of patients treated for intracranial neoplasm is a major concern to clinicians and patients, particularly as long-term survival or cure is possible for a small minority of patients. To assess the effects of cranial radiotherapy and chemotherapy on the cognitive performance of high-grade glioma patients, we analyzed cognitive performance data collected in a series of prospective clinical trials. METHODS: We studied 701 high-grade brain tumor patients entered onto two consecutive North Central Cancer Treatment Group (NCCTG) randomized treatment trials designed to compare radiotherapy and carmustine (BCNU) versus radiotherapy and 1-(2-chloroethyl)-3(2,6 dioxo-l-piperidyl)-1-nitrosource a (PCNU) (first trial) and radiotherapy and BCNU and interferon alfa (IFN) versus radiotherapy and BCNU (second trial). Folstein Mini-Mental Status Exam (MMSE) score and Eastern Cooperative Oncology Group (ECOG) performance score (PS) recorded at baseline and 6, 12, 18, and 24 months were analyzed to assess cognitive and physical function over time. Patients who did not demonstrate tumor progression within 60 days of the assessment time were considered nonprogressors at that evaluation. A loss of greater than 3 points on the MMSE was considered significant deterioration. RESULTS: The number of patients who experienced a greater than 3-point decrease in MMSE from baseline was 13 of 119 nonprogressors (10.9%; 95% confidence interval [CI], 6.3% to 18.9%) at 6 months, three of 54 nonprogressors (5.5%; 95% CI, 0.5% to 12.8%) at 12 months, three of 30 nonprogressors (10%; 95% CI, 2.1% to 26.5%) at 18 months, and four of 22 nonprogressors (18.2%; 95% CI, 5.2% to 40.3%) at 24 months. The CIs at all times overlapped, which indicates no statistically significant increase in the percentage of patients who experienced a significant decrease in their MMSE score. Patients who demonstrated a significant decrease in their MMSE score were significantly older than those who did not (P = .0017) at 6 months and remained so throughout follow-up; moreover, they had a significantly shorter time to progression and death. ECOG PS was strongly negatively correlated with MMSE score throughout the study, and MMSE score at all time intervals was correlated with baseline PS. CONCLUSION: In this population of glioma patients who received radiotherapy, there is no clear trend to cognitive worsening. Factors such as older age, poorer PS, and subclinical tumor progression may be more significant factors in those patients who did demonstrate a significant cognitive decline.

Adolescent↗
PubMed1998

The natural history of asymptomatic meningiomas in Olmsted County, Minnesota.

To define the natural history of asymptomatic meningioma found incidentally on a neuroimaging study, we performed a retrospective analysis of 35 such patients. There were 32 women and three men, with a mean age of 67 years and a mean follow-up of 74 months. Four tumors had progressed on subsequent imaging, and one patient developed symptoms related to the meningioma. Noncalcified tumors were more likely to progress than calcified tumors.

Adolescent↗
PubMed1998

Clinical and pathophysiological effects of active and passive smoking on the cardiovascular system.

Both passive and active cigarette smoking increase the risk of cardiovascular disease, the leading cause of death in Western industrialized nations. The prevalence of smoking as a major cardiovascular risk factor has been well characterized over the past 30 years. The two demographic groups of particular concern are women and the young. The relationship between active tobacco smoking and increased risk of coronary artery disease (stable and unstable angina, acute myocardial infarction or sudden death), cerebrovascular disease (cerebral infarction, and cerebral and subarachnoid hemorrhage), peripheral arterial disease (large and small vessel) and aortic aneurysm has been well established in numerous longitudinal and cross-sectional epidemiological and basic science studies. More recently, passive smoking has been shown to represent an important risk factor for coronary artery disease. Smoking can elicit both acute and chronic cardiac and vascular events due to the multiplicity of mechanisms involved: hematological, neurohormonal, metabolic, hemodynamic, molecular genetic and biochemical pathways. Smoking cessation can result in both the inhibition of progression and the regression of pathophysiological changes, improving morbidity and mortality among chronic smokers. The incidence of coronary artery and cerebrovascular diseases in former smokers decreases by 50% two to three years following cessation, but a small long term excess risk persists. Smoking as a cardiovascular risk factor and the clinical cardiovascular features associated with active and passive smoking are discussed, and a pathophysiological framework to explain the association between cigarette smoking and cardiovascular disease is provided.

Cardiovascular Diseases↗
PubMed1997

Cloning, and molecular characterization of the GCV1 gene encoding the glycine cleavage T-protein from Saccharomyces cerevisiae.

We have isolated the gene encoding the glycine cleavage T-protein (GCV1) of the yeast Saccharomyces cerevisiae and shown through gene disruption and enzyme assays that inactivation of GCV1 destroys glycine cleavage function. A DNA fragment encoding the GCV1 gene was cloned by PCR amplification using degenerate oligodeoxyribonucleotides, and the cloned fragment was used as a probe to isolate the complete gene from a yeast genomic library. Growth with glycine stimulated expression of the GCV1 gene as determined by Northern analysis and increased the beta-galactosidase activity of a GCV1-lacZ fusion 30-fold. The URA3 gene was inserted into the coding sequence of GCV1 and the resulting construct was used to disrupt the chromosomal GCV1 gene in a diploid strain of yeast. gcv1::URA3 haploid derivatives grew normally or only slightly more slowly than the isogenic wild-type haploids. All gcv1 strains studied were unable to grow on glycine as a sole nitrogen source and lacked glycine cleavage enzyme activity. Growth of shm1 shm2 mutants was stimulated by glycine, whereas glycine could not supplement the growth of the isogenic gcv1 strain.

Amino Acid Oxidoreductases↗
PubMed1997

Magnetic resonance imaging in cancer-related lumbosacral plexopathy.

OBJECTIVE: To study the relative utility of computed tomography (CT) and magnetic resonance imaging (MRI) of the lumbosacral plexus in patients with systemic cancer and plexopathy. DESIGN: In a retrospective study, we identified all patients encountered at Mayo Clinic Rochester between 1987 and 1993 with a diagnosis of lumbosacral plexopathy, and we selected for analysis those with MRI scans of the plexus (an abnormal finding was not necessary for inclusion) and a clinical and electrophysiologic appearance consistent with a diagnosis of metastatic lumbosacral plexopathy. MATERIAL AND METHODS: The study group consisted of 31 patients (20 men and 11 women). The types of tumor were as follows: prostatic, 10 patients; colorectal, 7; bladder, 3; cervical, 3; and other, 8. Eighteen patients had received pelvic radiotherapy before diagnosis of lumbosacral plexopathy. All available MRI scans (in 27 patients) were reviewed blinded; the initial imaging report was used if the actual scans were unavailable (in 4). CT had been done in 22 patients, and results for 16 were available for blinded review. Original reports were available for the other six. RESULTS: Direct involvement of the lumbosacral plexus by tumor was evident on 23 MRI studies, and 6 others showed widespread metastatic disease in the region of the plexus. On 13 CT examinations, direct involvement of the lumbosacral plexus by tumor was noted. In four patients, MRI findings were abnormal and CT findings were normal. No patient had abnormal CT findings and normal MRI findings. CONCLUSION: In this retrospective review, MRI was more sensitive than CT for diagnosing cancer-induced lumbosacral plexopathy. Thus, use of MRI should be considered in the diagnostic work-up of patients with clinical and electrophysiologic evidence of plexopathy and suspected systemic cancer.

Diagnosis, Differential↗
PubMed1996

The sensitivity and specificity of anti-GM1 antibody testing.

Elevated titers of antibodies directed at ganglioside epitopes have been associated with multifocal motor neuropathy (MMN), motor variant of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), amyolrophic lateral sclerosis (ALS), and other motor neuropathies. Anti-GM1 antibodies were measured in 675 patients: 180 age- and sex-stratified healthy blood bank controls, 132 normal controls who had full neurologic assessment including electromyography, 121 patients with definite ALS, 19 patients with pure sensory neuropathy, and 173 consecutive patient serum samples submitted for GM1 antibody testing. Antibodies to three ganglioside epitopes were determined by ELISA: IgM and IgG anti-monosialo GM1, asialo GM1, and disialo GD1b. Antibody titers for normal subjects and patients with ALS were used to determine normal values and borderline levels below which 99% of normal and 99% of ALS patient titers were found. Clinical evaluation of the next 173 consecutive patients referred for anti-GM1 antibody testing revealed 36 patients with motor neuropathies. Sera from 18 of these patients had titers above the 99% normal threshold and 14 had titers above the ALS and normal borderline threshold. All 14 with elevated sera titers were from patients with motor neuropathy or neuronopathy. Sixteen patients met the clinical and electrophysiologic criteria for MMN; 10 had elevated titers. Ten patients had the motor variant of CIDP without conduction block and three had elevated titers. Anti-IgM asialo GM1 antibodies had the highest sensitivity and specificity. High-titer IgM antibodies against monosialo GM1 occurred only in patients with various forms of pure motor neuropathy (100% specificity). The sensitivity was 50% for this referral-based population.

Adult↗
PubMed1995

Chronic inflammatory demyelinating polyneuropathy complicating liver transplantation.

We report on a patient who had chronic inflammatory demyelinating polyradiculoneuropathy following liver transplantation for hepatitis B-induced fulminate hepatic failure. Possible symptomatic recurrence of hepatitis B in the graft prompted a reduction in the cyclosporine dosage, which may have triggered the immune response leading to demyelination. Initial plasma exchange and then intravenous immune globulin after relapse led to marked clinical improvement.

Adult↗
PubMed1994

Cloning and molecular characterization of three genes, including two genes encoding serine hydroxymethyltransferases, whose inactivation is required to render yeast auxotrophic for glycine.

The genes encoding both the cytosolic and mitochondrial serine hydroxymethyltransferases (SHM2 and SHM1, respectively) and a third unidentified gene of the yeast Saccharomyces cerevisiae have been isolated and their nucleotide sequences determined. Analysis of the predicted amino acid sequence of the amino-terminal regions, sequence comparison with other genes encoding SHMT enzymes, and subcellular fractionation studies all suggested that the SHM1 gene encodes the mitochondrial SHMT, while the SHM2 gene encodes the cytosolic enzyme. The SHM2 gene but not the SHM1 gene has putative GCN4 sites upstream of the putative TATA box, suggesting regulation of its transcription by the general amino acid control system. Yeast mutants with disruptions at each SHM gene and in both genes were constructed and all mutants had the same growth requirements as the parental strains. Mutagenesis of the double-disrupted, shm1 shm2 yeast yielded strains of a single complementation group that are auxotrophic for glycine. Complementation of the glycine auxotrophy using a yeast genomic library retrieved the SHM1 and SHM2 genes and a third gene designated GLY1. Gene disruption studies demonstrated that inactivation of SHM1, SHM2, and GLY1 is required to yield yeast that are completely auxotrophic for glycine.

Aldehyde-Lyases↗
PubMed1994

Validation of a clinical classification for subtypes of acute cerebral infarction.

The validity of a clinical classification system was assessed for subtypes of cerebral infarction for use in clinical trials of putative stroke therapies and clinical decision making in a population based stroke register (n = 536) compiled in Perth, Western Australia in 1989-90. The Perth Community Stroke Project (PCSS) used definitions and methodology similar to the Oxfordshire Community Stroke Project (OCSP) where the classification system was developed. In the PCSS, 421 cases of cerebral infarction and primary intracerebral haemorrhage (PICH), confirmed by brain imaging or necropsy, were classified into the subtypes total anterior circulation syndrome (TACS), partial anterior circulation syndrome (PACS), lacunar syndrome (LACS), and posterior circulation syndrome (POCS). In this relatively unselected population, relying exclusively on LACS for a diagnosis of PICH had a very low sensitivity (6%) and positive predictive value (3%). Comparison of the frequencies and outcomes (at one year after the onset of symptoms) for each subgroup of first ever cerebral infarction in the PCSS (n = 248) with the OCSP (n = 543) registers showed uniformity only for LACI. For example, there were 27% of cases of TACI in the PCSS compared with 17% in the OCSP (difference = 10%; 95% confidence interval (95% CI) 4% to 16%) and 15% of cases in the PCSS compared with 24% in the OCSP were POCI (difference = 9%; 95% CI 3% to 15%). Case fatalities and long-term handicap across the subgroups were not significantly different between studies, but the frequencies of recurrent stroke were significantly greater for POCI in the OCSP compared with the PCSS. Although this classification system defines subtypes of stroke with different outcomes, simple clinical measures-level of consciousness, paresis, disability, and incontinence at onset-are more powerful predictors of death or dependency at one year. It is concluded that simple clinical measures that reflect the severity of the neurological deficit should complement this classification system in clinical trials and practice.

Acute Disease↗
PubMed1993

Cloning and sequence determination of the valS gene, encoding valyl-tRNA synthetase in Lactobacillus casei.

The DNA sequence of the valS gene from Lactobacillus casei and the predicted amino acid sequence of its valyl-tRNA synthetase product have been determined. An open reading frame coding for a protein of 901 amino acids was found. A clone containing the intact L. casei valS gene functionally complemented the temperature-sensitive growth of the valS mutant strain 236c of Escherichia coli. The valS gene and the downstream folylpolyglutamate synthetase gene are transcribed in the same direction but are separated by a putative transcription terminator.

Amino Acid Sequence↗