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Biomedical subjects

S L Walker

Publications and source records attributed to S L Walker.

At least 19 recordsLinked to original sources
PubMed2006

The clinical and immunological features of leprosy.

Leprosy is a granulomatous disease affecting the skin and nerves caused by Mycobacterium leprae. It continues to be a significant public health problem. Multidrug therapy (MDT) cures the infection, but immunological reactions may occur and neuropathy may lead to disability and deformity. It is important that the manifestations of the condition are recognized as early as possible so that early nerve damage can be identified and treated rapidly.

Diagnosis, Differential↗
PubMed2006

Sub-cutaneous phaeohyphomycosis caused by Cladophialophora devriesii in a United Kingdom resident.

An 83-year-old diabetic man receiving corticosteroids developed a forearm lesion. Histology confirmed the presence of a dematiaceous fungus, with associated granulomatous inflammation. Culture of a biopsy yielded fungal colonies with branching chains of single-celled, melanised, dry, sympodial conidia, which were identified as Cladophialophora devriesii on the basis of morphology and rDNA gene sequencing. To date, C. devriesii has been a relatively rare cause of human disease. To our knowledge, this is only the second case to be described, and the first report of infection in a UK resident.

Aged, 80 and over↗
PubMed2006

Toxicodendron dermatitis in the UK.

BACKGROUND: We present two cases of Toxicodendron dermatitis, one acquired in the United States but presenting in the United Kingdom (UK), the other a recurrent dermatitis following importation of the plant to the UK. Poison ivy, poison oak and poison sumac are native to North America and belong to the genus Toxicodendron. This group of plants is of interest to the dermatologist because they contain a mixture of potent sensitisers which cause a severe allergic contact dermatitis. CONCLUSIONS: The dermatitis can present to the dermatologist in Europe after an individual has been in contact with the plant whilst visiting an endemic area. The plants have the potential to grow in Europe and it is therefore possible for an individual to be sensitised and subsequently to develop the rash without leaving the continent.

Adult↗
PubMed2004

Noninvasive monitoring of adrenocortical activity in carnivores by fecal glucocorticoid analyses.

Measurement of glucocorticoid metabolites in feces has become an accepted method for the noninvasive evaluation of adrenocortical activity. The objective of this study was to determine if a simple cortisol enzyme immunoassay (EIA) was suitable for monitoring adrenocortical activity in a variety of carnivore species. Performance of the cortisol EIA was gauged by comparison to a corticosterone radioimmunoassay (RIA) that has been used for measuring glucocorticoid metabolites in feces of numerous species. Tests for parallelism and extraction efficiency were used to compare the cortisol EIA and corticosterone RIA across eight species of carnivores (Himalayan black bear, sloth bear, domestic cat, cheetah, clouded leopard, black-footed ferret, slender-tailed meerkat, and red wolf). The biological relevance of immunoreactive glucocorticoid metabolites in feces was established for at least one species of each Carnivora family studied with an adrenocorticotropic hormone (ACTH) challenge. High performance liquid chromatography (HPLC) analysis of fecal extracts for each species revealed (1) the presence of multiple immunoreactive glucocorticoid metabolites in feces, but (2) the two immunoassays measured different metabolites, and (3) there were differences across species in the number and polarities of metabolites identified between assay systems. ACTH challenge studies revealed increases in fecal metabolite concentrations measured by the cortisol EIA and corticosterone RIA of approximately 228-1145% and approximately 231-4150% above pre-treatment baseline, respectively, within 1-2 days of injection. Concentrations of fecal glucocorticoid metabolites measured by the cortisol EIA and corticosterone RIA during longitudinal evaluation (i.e., >50 days) of several species were significantly correlated (P<0.0025, correlation coefficient range 0.383-0.975). Adrenocortical responses to physical and psychological stressors during longitudinal evaluations varied with the type of stimulus, between episodes of the same stimulus, and among species. Significant elevations of glucocorticoid metabolites were observed following some potentially stressful situations [anesthesia (2 of 3 subjects), restraint and saline injection (2 of 2 subjects), restraint and blood sampling (2 of 6 episodes), medical treatment (1 of 1 subject)], but not in all cases [e.g., gonadotropin injection (n=4), physical restraint only (n=1), mate introduction/breeding (n=1), social tension (n=1), construction (n=2) or relocation (n=1)]. Results reinforced the importance of an adequate baseline period of fecal sampling and frequent collections to assess adrenocortical status. The corticosterone RIA detected greater adrenocortical responses to exogenous ACTH and stressful exogenous stimuli in the Himalayan black bear, domestic cat (female), cheetah, clouded leopard, slender-tailed meerkat, and red wolf, whereas the cortisol EIA proved superior to resolving adrenocortical responses in the black-footed ferret and domestic cat (male). Overall results suggest the cortisol EIA tested in this study offers a practical method for laboratories restricted in the usage of radioisotopes (e.g., zoological institutions and field facilities) to integrate noninvasive monitoring of adrenocortical activity into studies of carnivore behavior and physiology.

Acinonyx↗
PubMed2004

A simple method to assess severity of polymorphic light eruption.

BACKGROUND: The severity of polymorphic light eruption (PLE) is highly variable. The results of studies of the prevalence, pathogenesis, provocation and treatment of PLE may be highly dependent on the severity of disease in the patients studied. OBJECTIVES: To produce a simple, valid and reproducible method to assess the severity of PLE. PATIENTS AND METHODS: Eighty patients were asked about the PLE they had experienced during the preceding 12 months, using a standardized interview comprising 16 questions. The answer to each question received a score. A PLE Severity Index (PLESI) was formulated, consisting of 10 questions, with a possible total score of 2-100. The internal consistency of the PLESI (the extent to which the responses to different questions correlated with each other) was assessed by reliability analysis, using Cronbach's method. Twenty patients were re-interviewed 7-27 days later to assess the repeatability of the PLESI. The ease of provocation of PLE by exposure at 24-h intervals to solar-simulated radiation was assessed on a five-point scale in nine of the 80 subjects (the EOPSSR score). RESULTS: The value of Cronbach's alpha for the PLESI was 0.77. The distribution of the PLESI was consistent with a normal distribution, with a mean value of 52.7 and standard deviation of 19.4. It had a coefficient of repeatability of 20.1. The PLESI was positively correlated with EOPSSR (rs =0.69, P = 0.039) and the number of years since onset of PLE (rs = 0.25, P = 0.03). There was no association between the PLESI and the duration of persistence of the eruption after ceasing sun exposure (rs = 0.12, P = 0.30), the development of tolerance as summer progressed (rs = -0.14, P = 0.39), gender (P = 0.50) or skin type (P = 0.87). CONCLUSIONS: This study has (i) validated the concept that a single score can reflect disease severity in PLE by showing that the principal characteristics of the condition, including, for example, the extent of anatomical distribution and the ease of provocation of the eruption, correlate with each other; (ii) formulated the PLESI, which is a simple, valid and reproducible way of assessing disease severity; we suggest it could be used worldwide to determine the severity of PLE among patients enrolled in future PLE research; (iii) shown that the ease with which the eruption is provoked by solar-simulated radiation correlates with the severity of the condition; and (iv) shown that the duration of persistence of the eruption after sun exposure does not correlate with the severity of the condition.

Adolescent↗
PubMed2002

Rapid detection of Obesumbacterium proteus from yeast and wort using polymerase chain reaction.

AIMS: To design and evaluate PCR primers for the rapid detection of Obesumbacterium proteus. METHODS AND RESULTS: The 16S rDNA from a wild-type Obesumbacterium proteus biotype II isolate was sequenced and the resultant data used to produce specific primers for this organism. These primers discriminated between biotype I (nonbrewery) and biotype II isolates. In addition, the primers were able to detect Obesumbacterium proteus in wort and in yeast slurries in the presence of competitive bacteria. The primers were tested against a range of other beer spoilage bacteria for any cross-reactions. None were detected. CONCLUSIONS: Obesumbacterium proteus primers can detect this contaminant without generating cross-reactions to related species. SIGNIFICANCE AND IMPACT OF THE STUDY: The primers generated in this study can now be used for PCR detection assays that will contribute to early detection of this important process contaminant.

Beer↗
PubMed2002

Consumer acceptance of raw apples treated with an antibacterial solution designed for home use.

An antibacterial treatment consisting of 1.5% lactic acid plus 1.5% hydrogen peroxide at 40 degrees C for 15 min was effective in reducing foodborne bacterial pathogens on raw apples. However, the effects of this treatment on an apple's sensory characteristics and the extent of consumers' willingness to use the treatment at home were not known. This study was undertaken to determine the sensory acceptability and chemical characteristics (pH, soluble solids, and total acidity) of apples subjected to the sanitizing treatment and to obtain information on consumers' purchase behavior, apple handling and consumption practices, and willingness to use an antibacterial treatment. Untrained consumers (n = 80) evaluated the appearance, color, aroma, flavor, texture, and overall appeal of untreated (control) and treated Red Delicious apples that had been stored at 5 degrees C for 0, 6, and 10 days. Panelists used a nine-point hedonic scale (1 = "dislike extremely"; 5 = "neither like nor dislike"; 9 = "like extremely") to evaluate sensory acceptability. Treatment and storage had no significant effect on the appearance, color, or aroma of the samples. Flavor ratings ranged from 6.2 ("like slightly") to 7.0 ("like moderately"). There was no significant difference among any of the control and treated apples stored for 0 days or among those stored for 6 days. Although apples stored for 10 days received the lowest ratings (6.2 to 6.3), they still had an acceptable flavor (6, "like slightly"), and panelists could not perceive differences between the control samples and the treated samples on day 10. The same trends were noted in texture ratings and in overall liking ratings. Treatment and storage had a minimal effect on pH (range, 3.96 to 4.02), soluble solids (range, 11.8 to 12.9 degrees Brix), and total acidity (range, 0.20 to 0.23% malic acid), which are important for apple flavor. Many consumers (87%) were concerned about fruit safety, and 53.2% were willing to try an antibacterial treatment at home. However, 74% would not be willing to use it if a 15-min heating-and-soaking step were required. Implementation of the treatment may be more feasible in the packinghouse than in the home.

Consumer Behavior↗