Biomedical subjects
P Williams
Publications and source records attributed to P Williams.
Comparison of aflatoxigenic and nonaflatoxigenic isolates of Aspergillus flavus using DNA amplification fingerprinting techniques.
Aspergillus flavus is a filamentous fungus that produces mycotoxins in many food and feed crops, such as maize (Zea mays L.). Isolates were analyzed for toxin production by nucleic acid profiles in an attempt to differentiate aflatoxigenic from nonaflatoxigenic isolates. A total of 41 aflatoxigenic and 34 nonalfatoxigenic isolates were included in the study. The isolates were evaluated initially using DNA amplification fingerprinting (DAF) without clear resolution of the groups. A weak association of aflatoxigenic isolates was observed, as evidenced by their clustering in 18 of 81 trees recovered from maximum parsimony analysis of binary characters derived from arbitrary signatures from amplification profiles (ASAP) data; nonaflatoxigenic isolates exhibited a pattern of paraphyletic laddering. Up to five markers unambiguously supported the aflatoxigenic isolate grouping, but the presence of alternative conflicting topologies in equally parsimonious trees precluded the observation of meaningful statistical support. With additional markers for genome of A. flavus, this method could be used to resolve toxigenic from nontoxigenic strains. This additional work could resolve aflatoxigenic isolates of A. flavus present on maize plants using ASAP, which would reduce labor intense costs and potentially lead to faster determination of resistant cultivars in breeding efforts.
Folliculitis spinulosa decalvans: failure to respond to oral isotretinoin.
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Biosolids-amended soils: Part I. Effect of biosolids application on soil quality and ecotoxicity.
Investigations of potential risk from biosolids generally indicate that land application does not threaten human or ecosystem health, but questions continue to arise concerning the environmental effects of this practice. This research project was initiated to evaluate ecotoxicity resulting from the amendment of soils with biosolids from municipal wastewater treatment plants. Toxicity was evaluated using standard tests, including earthworm mortality, growth, and reproduction; seedling germination and root elongation; microbial respiration; and nematode mortality and reproduction. Nineteen municipal wastewater treatment plants were identified to participate in an initial screening of toxicity, and five were chosen for a more detailed evaluation. In addition, two soils with historically high applications of high-metal biosolids were evaluated. Contaminants examined were zinc, copper, nickel, chromium, arsenic, cadmium, lead, and coplanar polychlorinated biphenyls (PCBs). Single applications had no effect on soil metal concentrations. Coplanar PCBs were not detectable in any of the soils or biosolids. All target organisms were sensitive to reference toxicants. Limited toxicity was observed in a small number of the amended soils, but no patterns emerged. Approximately one-half of the negative effects of biosolids on bioindicators could be attributed to routine properties, such as slight depression of pH and/or elevated salinity. None of the accumulated metal concentrations were excessive, and most would not be considered elevated. These observations suggest that current regulations for application of biosolids to soils are providing adequate ecosystem protection.
Dispersion of organically modified clays within n-alcohols.
A method for formation of polymer-clay nanocomposites involves dispersion of the nanometer silicate layers of clays into a solvent, followed by dispersion into polymers. The dispersion of layered silicates within solvents affects the structure and properties of the nanocomposites. We report the dispersion of organically modified clays, used for formation of nanocomposites with organic polymers, within a range of alcohol solvents. Experiments involved stirring a mixture containing approximately 1 wt% of alkylammonium-modified clays in n-alcohols with general molecular structure RnOH, where n represents the number of carbons of alkyl chains, varying from 2 to 8. The clays precipitated from the dispersion when RnOH solvents with n<5 were used, however, they formed gels for solvents with n5. The increased dispersion was related to the decrease of polarity and hydrogen bonding force within solvents. X-ray diffraction for the dispersed clays indicated that the interlayer spaces (1.8 nm), formed by regular stacking of the silicate layers, expanded to a maximum of 3.0 nm after treatment with RnOH with n5. The interlayer expansion was due to the intercalation of n-alcohol molecules within the interlayer spaces. It is suggested that the alkyl chains of n-alcohols remain parallel to the silicate surface in the intercalate. Preliminary experiments on the influence of these alcohol solvents on the intercalation of polyol (polyether) are also reported.
Distinct phenotype associated with a cryptic subtelomeric deletion of 19p13.3-pter.
Telomeres are gene rich regions with a high recombination rate. Cryptic subtelomeric rearrangements are estimated to account for 5% of mental retardation/malformation syndromes. Here we present the first patient with a deletion of 19p13.3, identified by subtelomeric FISH analysis. His features included a distinctive facial appearance, cleft palate, hearing impairment, congenital heart malformation, keloid scarring, immune dysregulation, and mild learning difficulties. Subtelomeric FISH analysis identified a deletion of 19p13.3-pter. The deletion size was determined to be 1.2 Mb by FISH analysis. It extended from within the chromosomal region covered by BAC RP11-50C6 to 19pter. The deleted area encompassed approximately 60 genes. Fifteen possible candidate genes were considered with respect to the phenotype, including follistatin-related precursor 3 (FSTL3) and serine-threonine kinase 11 (STK-11).
The use of multiattribute decision models in evaluating triptan treatment options in migraine.
BACKGROUND: The physician treating patients with migraine is now able to choose from among seven triptans-almotriptan, eletriptan, frovatriptan, naratriptan, rizatriptan, sumatriptan and zolmitriptan. These differ, to greater or lesser degrees, on a range of clinical attributes important for treatment selection. OBJECTIVE: To outline the basic principles of Multiattribute Decision Making (MADM) and describe how one such method-TOPSIS (Technique for Order Preference by Similarity to the Ideal Solution)-can be applied to evaluate the currently available triptans. METHODS: In an example application, summary data from a recent meta-analysis of 53 published and unpublished placebo-controlled trials of the oral triptans were combined in TOPSIS models with computer-generated attribute importance weights representing the entire range of possible values, That is, the relative performance of the triptans was explored across all logically possible combinations of relative importance of the treatment attributes available from the meta-analysis, and uncertainty was assessed based on the confidence intervals from the meta-analysis. RESULTS: When compared across the entire range of values for relative attribute importance, almotriptan, eletriptan and rizatriptan were more similar to a hypothetical ideal triptan and were more likely to appear in the top three closest to the hypothetical ideal, than were naratriptan, sumatriptan, and zolmitriptan. CONCLUSION: Using the TOPSIS model, almotriptan, eletriptan and rizatriptan were more likely to appear in the top three closest to the hypothetical ideal triptan.
Predictors of cognitive dysfunction in patients with systemic lupus erythematosus.
OBJECTIVE: To evaluate predictors of cognitive dysfunction in patients with systemic lupus erythematosus (SLE). METHODS: The authors evaluated 123 patients enrolled in the San Antonio Lupus Study of Neuropsychiatric Disease (SALUD) who had completed at least 3 years of follow-up. Study visits occurred every 4 months and included a standard medical history, physical examination, and cognitive testing. Blood was obtained at each study visit for autoantibody testing. RESULTS: There were 116 (94.3%) women and 7 (5.7%) men (mean age = 41.5 [+/-12.0] years). Patients had the following vascular risk factors: hypercholesterolemia (17.1%), diabetes (21.1%), and hypertension (48.0%). Consistent medication use included aspirin (21.1%), prednisone (65.0%), nonsteroidal anti-inflammatories (42.3%), and hydroxychloroquine (58.5%). The numbers of patients with consistently positive autoantibody levels were as follows: antiphospholipid, 54%; anti-beta-2-glycoprotein 1, 73%; and anti-ribosomal P, 17%. Factors significantly associated with declining cognitive function were consistently positive antiphospholipid antibodies, consistent prednisone use, diabetes, higher depression scores, and less education. The association of prednisone and poorer cognitive function was seen primarily in the middle age group and could not be totally explained by SLE-associated disease activity. Consistent aspirin use was associated with improved cognitive function, primarily in the oldest age group, especially if diabetes was also present. CONCLUSIONS: Regular aspirin use is associated with improved cognitive function in older patients with systemic lupus erythematosus (SLE) in conjunction with the presence of other vascular risk factors. Regular prednisone use is associated with decreased cognitive functioning in middle-aged patients with SLE. Although this prednisone effect was independent of measures of SLE-associated disease activity, the authors cannot exclude the possibility that consistent prednisone use is a surrogate for more severe disease.
Discerning alumina ball wear from confounding metal transfer artifact.
On dismounting a ceramic femoral ball from its metal trunnion, there is usually a range of gray metallic bands transferred to the trunnion bore inside the ball. This creates an artifact that may compromise detection by weight of the exceedingly low wear rates of ceramic balls. The objective of this study was to compare the weight trending of the metal trunnions and their ceramic balls during conditioning studies. Our hypothesis was that a pretest conditioning protocol would eliminate or greatly reduce the metal transfer artifact. The balls and tapers were placed on a hip simulator under 300-600 load cycles but with no articulation. The balls were then dismounted from the trunnions, and both were cleaned and weighed. This was repeated 6-23 times. We developed a novel hydraulic method for dismounting balls from trunnions that proved to be safe and efficient. There was significant weight loss in the trunnions after the ball removal, but there was no corresponding weight gain in the alumina balls. The weight effect of the metal transfer appeared to have been removed from the balls with our standard cleaning procedures. Therefore, wear rates for alumina balls may be gravimetrically determined without compensating for the metal transfer from trunnion to ball.
Alleviation of insulitis and moderation of diabetes in NOD mice following treatment with a synthetic Pseudomonas aeruginosa signal molecule, N-(3-oxododecanoyl)-L-homoserine lactone.
Quorum sensing signal molecules (QSSMs) from the bacterium Pseudomonas aeruginosa control bacterial population density and the expression of virulence determinants. Coincidentally, and possibly to allow this pathogen to gain a foothold in the human body, certain signal molecules also downregulate immunological responses in an apparently T-helper 1-selective manner, which would suggest their application as therapeutics to some autoimmune diseases. In the present paper, experiments are described that indicate that one particular signal molecule, a synthetic N-(3-oxododecanoyl)-L-homoserine lactone, can be used to alleviate insulitis and diabetes in non-obese diabetic (NOD) mice, suggesting that bacterial signal molecules may represent a novel source of immune modulatory compounds for the treatment of type 1 diabetes, which afflicts more than 2 million individuals in Europe and North America.
Radiographers and radiologists reporting plain radiograph requests from accident and emergency and general practice.
AIM: To assess selectively trained radiographers and consultant radiologists reporting plain radiographs for the Accident and Emergency Department (A&E) and general practitioners (GPs) within a typical hospital setting. METHODS: Two radiographers, a group of eight consultant radiologists, and a reference standard radiologist independently reported under controlled conditions a retrospectively selected, random, stratified sample of 400 A&E and 400 GP plain radiographs. An independent consultant radiologist judged whether the radiographer and radiologist reports agreed with the reference standard report. Clinicians then assessed whether radiographer and radiologist incorrect reports affected confidence in their diagnosis and treatment plans, and patient outcome. RESULTS: For A&E and GP plain radiographs, respectively, there was a 1% (95% confidence interval (CI) -2 to 5) and 4% (95% CI -1 to 8) difference in reporting accuracy between the two professional groups. For both A&E and GP cases there was an 8% difference in the clinicians' confidence in their diagnosis based on radiographer or radiologist incorrect reports. For A&E and GP cases, respectively, there was a 2% and 8% difference in the clinicians' confidence in their management plans based on radiographer or radiologist incorrect reports. For A&E and GP cases, respectively, there was a 1% and 11% difference in effect on patient outcome of radiographer or radiologist incorrect reports. CONCLUSION: There is the potential to extend the reporting role of selectively trained radiographers to include plain radiographs for all A&E and GP patients. Further research conducted during clinical practice at a number of sites is recommended.
Australian consumers are sceptical about but influenced by claims about fat on food labels.
OBJECTIVES: To explore the beliefs and attitudes of Australian consumers to claims about fat made on the labels of packaged food. DESIGN: Content analysis of transcripts from focus group discussions. SUBJECTS: A total of 26 female and 10 male participants aged 20-80 y, recruited by advertisement into six focus groups, stratified by age, sex and health status. RESULTS: Awareness of claims about fat was high in this sample of Australians and participants admitted that they influenced their purchase decisions. The most preferred form of claim was 'X% fat free'. Claims were considered most useful on foods that were high in fat. There was considerable scepticism about all nutrient claims, and consumers preferred to check claims about fat against the values in the nutrition information panel. Many claims were seen as advertising that could be misleading, deceptive or confusing. While claims about fat might prompt product trial, factors such as price, taste, naturalness, as well as other nutritional factors, also influenced purchase decisions. Some consumers believe low fat claims encourage over consumption of foods. CONCLUSIONS: Changes to regulations governing nutrition claims on food labels should be made to enhance their credibility and support their role in assisting consumers to make healthier food choices.
HCV and HIV-1 donor screening using nucleic acid amplification technique (NAT).
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Tension pneumothorax complicating autologous "blood patch" pleurodesis.
Autologous "blood patching" has been used successfully for the treatment of persistent air leak in patients with spontaneous secondary pneumothorax. The case history is presented of a 19 year old woman with cystic fibrosis who developed tension pneumothorax following this procedure, with rapid clinical deterioration until the obstruction was cleared. To avoid this potentially fatal complication we recommend that "blood patch" pleurodesis be performed only through large bore intercostal catheters, that blood is rapidly transferred into the catheter tubing, a sterile saline flush and full resuscitation equipment is available, and the operator is skilled in the management of tension pneumothorax.
How treatment priorities influence triptan preferences in clinical practice: perspectives of migraine sufferers, neurologists, and primary care physicians.
BACKGROUND: In treating migraine sufferers, physicians can choose from among seven triptans with different attributes. OBJECTIVE: To develop a system for selecting an oral triptan based on treatment priorities of migraine sufferers, neurologists, and primary care physicians (PCPs) in the United States, and evidence-based performance of triptans in clinical trials. METHODS: The TRIPSTAR project combines data on the treatment preferences of migraineurs and physicians with results from a meta-analysis of individual triptans, which evaluated their effectiveness on various clinical endpoints. Telephone interviews with migraine sufferers, neurol ogists, and PCPs were conducted to elicit individual views on the relative importance of a prespecified set of acute treatment outcomes. Four hundred and fifteen migraine sufferers, both triptan-experienced and triptan-naive, were interviewed. Also, 200 board-certified neurologists and 200 PCPs provided information on migraine patients from their clinical practice. A multiattribute decision model for selecting an oral triptan was constructed using attribute importance weights collected at telephone interview and the meta-analysis data, which were drawn from 53 clinical trials of 6 oral triptans. RESULTS: Efficacy attributes were rated significantly more important than tolerability or consistency in selecting an oral triptan, according to migraine sufferers and physicians. Freedom from cardiovascular adverse events was the most important tolerability attribute, according to migraine sufferers and physicians alike. Pain free at 1 h was the most important lower-level efficacy attribute for migraine sufferers, while sustained pain free was most important for physicians. When weighted treatment attributes were combined with meta-analysis data in a multi-attribute decision model, almotriptan 12.5 mg, eletriptan 80 mg, and rizatriptan 10 mg were significantly closer to the hypothetical ideal triptan than was suma triptan 100 mg. Triptans selected by the model were generally closer to the patient-specific ideal triptan than were the triptans prescribed by physicians. CONCLUSIONS: Almotriptan, eletriptan, and rizatriptan were the three triptans closest to the ideal, from the perspectives of migraine sufferers, PCPs, and neurologists alike. The TRIPSTAR model may be a potentially useful decision-support tool to help physicians select the triptan most likely to produce a successful outcome in migraine sufferers.
Precision and accuracy in ceramic-on-ceramic wear analyses: influence of simulator test duration.
In this, the first report of precision and accuracy in simulator studies, ceramic-ceramic implants with ultra-low wear trends represented a relevant wear model. The effect of test durations was examined in a standard simulator test mode on the quality of the linear regression trends, the average wear estimates, and the amount of noise in the data. Three sets of diametral tolerances were compared in 28 mm diameter alumina implants. The authors' hypothesis was that wear data would be significantly improved with increased test durations. The average wear rates varied little with test duration, the biggest change amounting to only 30 and 15 per cent decreases in the wear estimate by 10 and 14 million cycles respectively. The most satisfactory improvement in the study was the decrease in variance (noise) with increasing duration, +/- 200 per cent at 5 million cycles reduced to +/- 55 per cent at 14 million cycles. The quality of the linear regression coefficients improved 150 per cent by 10 million cycles and 250 per cent by 14 million cycles. Overall the ceramic implants with highest diametral tolerances showed the least wear (15 per cent less, but not statistically significant). However, given such low wear rates for alumina liners, it was unlikely that any differences owing to diametral tolerances would be clinically significant in the typical patient.
Gas-phase diatomic trications of Se2(3+), Te2(3+), and LaF3+.
Three gas-phase diatomic trications Se(2) (3+), Te(2) (3+), and LaF(3+) have been produced by Ar(+) ion beam sputtering of Se, Te, and LaF(3) surfaces, respectively. These exotic molecular ions were detected at noninteger m/z values in a magnetic sector mass spectrometer for ion flight times of >/=13 micros that correspond to lower limits of their respective lifetimes. Se(2) (3+) and Te(2) (3+) were unambiguously identified by their characteristic isotopic abundances. Ab initio calculations of the electronic structures of Se(2) (3+), Te(2) (3+), and LaF(3+) show that these molecular trications are metastable with respect to dissociation into fragment ions of Se(2+)+Se(+), Te(2+)+Te(+), and La(2+)+F(+), respectively. Their barrier heights are about 0.49, 0.29, and 0.53 eV, and the equilibrium internuclear distances (bond lengths) are about 0.23, 0.27, and 0.26 nm, respectively. The gas-phase diatomic dications Se(2) (2+) and Te(2) (2+) were also observed and unambiguously identified. They were found to be long-lived metastable molecules as well, whereas LaF(2+) is thermochemically stable.