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Biomedical subjects

J Powell

Publications and source records attributed to J Powell.

At least 37 records · Page 2Linked to original sources

Comprehensive resource: Skeletal gene database.

The Skeletal Gene Database (SGD) is an integrated resource that provides comprehensive information about bone-related genes, mRNA, and proteins expressed in human and mouse, with rich links to numerous other electronic tools. SGD contains expressed sequence tag (EST) data from all the skeletal-related cDNA libraries that are available to the public. It supplies the query/data access analytic tools for users to search and compare each gene expressed in skeletal tissue(s). The results derived from EST tissue expression profiling will allow users to get the data on the mRNA copy numbers of each gene expressed in each tissue and its normalized value. From the SGD, researchers can obtain information regarding the name, symbol, size, exon/intron number, chromosomal location, LocusLink, and related disease (if any is known) of each gene. This electronic compendium also furnishes information on the protein of the corresponding gene including the protein size (amino acid number and molecular weight). It provides swift and ready access to other useful databases including OMIM, UniGene and PUBMED. The data will be updated regularly in step with current and future research, thereby providing what we hope will serve as a highly useful source of information and a powerful analytic tool to the scientific community.

Animals↗

Extracts of Flourensia cernua (L): volatile constituents and antifungal, antialgal, and antitermite bioactivities.

The chemical components of tarbush (Flourensia cernua) leaves were fractionated by extracting successively with hexanes, diethyl ether, and ethanol. Volatile profiles of each fraction were identified by using GC-MS. The hexanes fraction contained mostly monoterpenoids, while the ethanol fraction volatiles were primarily sesquiterpenoids. Crude fractions were tested for activity against fungi, algae, and termites. Application of as little as 1 microg of the essential oil from the hexanes fraction was sufficient to provide visible antifungal activity in bioautography assays. The diethyl ether fraction showed selective activity against the cyanobacterium responsible for the 2-methylisoborneol-induced off-flavor sometimes associated with catfish farming operations. All three fractions exhibited a high degree of antitermite activity.

Animals↗

Assessment of skin basement membrane zone antibodies in the urine of patients with acquired subepidermal immunobullous diseases.

BACKGROUND: In bullous pemphigoid (BP), cicatricial pemphigoid (CP) and linear IgA disease (LAD), autoantibodies to the basement membrane zone (BMZ) are found in skin and mucosa, blood and blister fluid. OBJECTIVES: To assess whether BMZ antibodies might also be detected in urine. METHODS: Urine and serum samples from 62 patients (32 with BP, 17 with CP and 13 with LAD) were analysed for antibody isotypes and subclasses by indirect immunofluorescence, and urine and serum samples from 40 patients (25 with BP, eight with CP and seven with LAD) were screened for target antigens using immunoblotting. RESULTS: Fourteen of 32 patients with BP had detectable levels of IgG BMZ autoantibodies in their urine, and all 32 had positive sera. Of these 14 BP patients, 13 had epidermal-binding serum autoantibodies at a titre > 1 : 160, and one had dermal-binding serum antibodies at a titre of 1 : 40. BMZ autoantibodies were not detected in the urine of the CP or LAD patients, but the corresponding sera were of low titre or negative. IgG subclasses (IgG1-4) were less frequently detected in urine than in serum. IgG4 was the predominant subgroup found (10 urine samples and all 14 sera), followed by IgG1 (two urine samples and 12 sera); IgG2 was detected in a single urine sample and three sera, and IgG3 was not detected. Eight of 25 BP and one of eight CP urine samples were positive on immunoblotting, and bound BP230 and/or BP180 with IgA and/or IgG autoantibodies. IgA autoantibodies were not detected in the urine of the seven LAD patients. The corresponding sera were often more positive, with 21 of 25 BP, five of eight CP and six of seven LAD sera immunoblotting the major BP antigens. CONCLUSIONS: The detection of IgG autoantibodies from urine samples using indirect immunofluorescence correlated with a high titre of IgG autoantibodies in the serum. IgG and IgA autoantibodies in the urine were detected by immunoblotting, although less frequently than in serum. The finding of BMZ antibodies in the urine of many BP patients may have clinical relevance, and may have a restricted application in the diagnosis of immunobullous disease.

Adult↗

Mixed immunobullous disease of childhood: a good response to antimicrobials.

BACKGROUND: Immunobullous diseases are uncommon in childhood. In contrast to adults, the most commonly seen is IgA-mediated chronic bullous disease of childhood (CBDC), while IgG-mediated bullous pemphigoid (BP), cicatricial pemphigoid (CP) and epidermolysis bullosa acquisita (EBA) are rare. We have demonstrated both IgG and IgA autoantibodies to basement membrane zone target antigens in eight children with 'mixed immunobullous disease of childhood'. OBJECTIVES: To elucidate whether a dual antibody response makes these patients distinct regarding their presentation, immunopathology, course and prognosis. METHODS: We compared the eight children showing the double antibody response with 62 children with CBDC, BP, CP and EBA in whom only one antibody isotype was demonstrated. Clinical information at presentation, clinical course and response to treatment were recorded, and immunoblotting and direct and indirect immunofluorescence (IF) were performed. RESULTS: Six of the eight patients presented with clinical features of CBDC. In two others, it was uncertain whether they had CBDC or BP. Seven of the eight demonstrated a dual antibody response on indirect IF and three on direct IF. Immunoblotting revealed a variety of epidermal and dermal target antigens (BP230, BP180, 97-kDa protein and laminin 5). Five of the eight responded well to dapsone, two to sulphonamides, and one to systemic erythromycin alone. The clinical course was not protracted. Five are in remission 1-4 years following treatment, and three still have active disease suppressed by treatment after 6 months-2 years. CONCLUSIONS: Although we do not know why these children have 'mixed immunobullous disease' (the dual antibody response), our results indicate that the presence of IgA is associated with a good response to treatment with antimicrobials (dapsone, sulphonamides, erythromycin), and the clinical course is no more protracted than that found in children with a single antibody response.

Anti-Infective Agents↗

High incidence of lichen sclerosus in patients with squamous cell carcinoma of the penis.

BACKGROUND: There is a well-documented association between lichen sclerosus (LS) and vulval carcinoma in women; however, until recently, there have only been anecdotal reports of penile squamous cell carcinoma (SCC) occurring in men with LS. OBJECTIVE: The incidence of penile carcinoma occurring on a background of LS remains uncertain, and we wished to examine this possible association further. METHOD: To address this, all the cases (n = 20) of penile SCC held on our pathology database (4 years) were examined. Histology was reviewed, blind to the clinical picture, for evidence of LS, applying strict histological criteria. Subsequently, clinical notes were reviewed for history of LS before the SCC presented, and history of previous circumcision, treatments, node involvement, metastases and death. RESULTS: In eight cases, evidence of LS was found in the excision specimen. Seven of these had well-differentiated SCC. In the 12 cases with no evidence of LS, only three were well differentiated. With case note review, seven had a history of LS (four with histological LS), sometimes preceding the SCC by 10 years. These all had well-differentiated SCC. Ten of the 20 patients are dead, seven from metastatic disease. Four deaths occurred in the 'well-differentiated LS' group, but only one from penile SCC metastatic disease. CONCLUSIONS: There appears to be a definite association between SCC of the penis and the presence of LS, similar to that reported between LS and vulval SCC in women. Of the 20 patients with penile SCC studied, 11 had a clinical history and/or histological evidence of LS. However, clinical presentation of the LS or need for circumcision may precede the SCC by many years. As follow-up is impractical, counselling at the time of diagnosis is very important, and it is essential that medical practitioners are aware of this association so that the subsequent risk from SCC is reduced.

Adult↗

Childhood vulvar lichen sclerosus: an increasingly common problem.

BACKGROUND: Lichen sclerosus (LS) of the vulva in children is presenting more commonly, but its origin is unknown. OBJECTIVE: The purpose of this study was to assess the prevalence of childhood vulvar LS, to examine factors that may play a role in its cause, and to attempt to define the current optimal treatment. METHODS: We surveyed 70 cases of LS currently being treated in the pediatric vulvar clinic to collect information on presentation, family history, associated disease, and typical course of the disorder. We looked retrospectively and prospectively at treatments for LS. RESULTS: We found a prevalence of premenarchal LS of 1 in 900 and confirmed an increasing incidence. In a high proportion of cases (77%), the question of sexual abuse had been raised. A family history of LS was found in a minimum of 17% of cases. Associated autoimmune disease occurred in 14%, but 64% told of a family history, and atopy occurred in 59%. Potent topical steroid ointments appear to alleviate symptoms most effectively, with minimal side effects. CONCLUSION: Although the cause of LS remains uncertain, it is not a rare disease in prepubertal girls. Current optimal management includes prompt diagnosis and institution of treatment with a potent topical steroid.

Adolescent↗

Semantic memory is impaired in both dementia with Lewy bodies and dementia of Alzheimer's type: a comparative neuropsychological study and literature review.

OBJECTIVE: To test the hypothesis that semantic impairment is present in both patients with dementia with Lewy bodies (DLB) and those with dementia of Alzheimer's type (DAT). METHODS: A comprehensive battery of neuropsychological tasks designed to assess semantic memory, visuoperceptual function, verbal fluency, and recognition memory was given to groups of patients with DLB (n=10), DAT (n=10) matched pairwise for age and mini mental state examination (MMSE), and age matched normal controls (n=15). RESULTS: Both DLB and DAT groups exhibited impaired performance across the range of tasks designed to assess semantic memory. Whereas patients with DAT showed equivalent comprehension of written words and picture stimuli, patients with DLB demonstrated more severe semantic deficits for pictures than words. As in previous studies, patients with DLB but not those with DAT were found to have impaired visuoperceptual functioning. Letter and category fluency were equally reduced for the patients with DLB whereas performance on letter fluency was significantly better in the DAT group. Recognition memory for faces and words was impaired in both groups. CONCLUSIONS: Semantic impairment is not limited to patients with DAT. Patients with DLB exhibit particular problems when required to access meaning from pictures that is most likely to arise from a combination of semantic and visuoperceptual impairments.

Aged↗

Psychosis and aggression in Alzheimer's disease: the effect of dopamine receptor gene variation.

This study investigated possible associations between selected polymorphisms in the dopamine receptor genes DRD1 and DRD3 with the presence of psychotic phenomena or aggressive behaviour in a community based cohort of 134 patients with late onset Alzheimer's disease. An association was found between the presence of psychotic symptoms and aggressive behaviour and the DRD1 polymorphism and between the presence of psychosis, but not aggression, and the DRD3 polymorphism. Specifically, carriers of the DRD1 B2 allele were more likely to be aggressive or experience hallucinations whereas homozygous carriers of the DRD3 1 allele were more likely to experience delusions.

Age of Onset↗

Increased common carotid intima-media thickness in UK African Caribbeans and its relation to chronic inflammation and vascular candidate gene polymorphisms.

BACKGROUND AND PURPOSE: Individuals of African Caribbean descent who live in the United Kingdom have an increased risk of stroke. The reasons for this are not fully understood, but differences in genetic predispositions or other novel stroke risk factors could play a role. US blacks have been reported to have increased common carotid artery wall thickness, or intima-media thickness (IMT), measured by ultrasound. We measured carotid IMT in UK African Caribbeans compared with UK whites and determined whether different distributions of polymorphisms in potential candidate vascular genes or differences in measures of chronic inflammation or infection could account for any difference. METHODS: In a population study, common carotid artery IMT was measured in 202 white men and 89 African Caribbean men. The distribution of polymorphisms in ACE, paraoxonase 1, paraoxonase 2, and methylenetetrahydrofolate reductase genes was determined. Serum C-reactive protein and Helicobacter pylori seropositivity were determined. RESULTS: Carotid IMT was increased in African Caribbeans even after controlling for cardiovascular risk factors, including homocysteine and social class: beta=0.113, 95% CI 0.036 to 0.189, P=0.004. There was a significant interaction with smoking and mean IMT (P=0.022), and the difference in both measures of IMT between ethnic groups was largely limited to individuals who had never smoked. There were significant ethnic differences in the distributions of 3 of the 4 candidate genes studied (ACE, paraoxonase 1, and methylenetetrahydrofolate reductase). H pylori seropositivity was increased in African Caribbeans (78.7% versus 53% in UK whites). However, neither the genetic polymorphisms nor H pylori seropositivity was related to IMT, and ethnic differences in their distribution did not account for the increased IMT seen in African Caribbeans. CONCLUSIONS: Carotid IMT is increased in UK African Caribbeans even after controlling for conventional risk factors. There are highly significant ethnic differences in the distribution of many potential cerebrovascular candidate genes. Although those we examined did not explain the ethnic differences in IMT, other genetic predispositions or environmental exposures could account for these differences.

Adult↗

Professional territories and the fragmented landscape of elderly care.

This paper examines the problems and dilemmas involved in delivering care to older people. In particular it seeks to identify the processes that facilitate or hinder communication and collaboration between those involved in care that has to be both reliable and expeditious to ensure that high quality care is provided. To do this the paper draws on a recent international systematic review of the relevant research literature which is briefly described. A geographical analogy is employed to help map different organisational and professional territories of care. It will be argued that these territories have their own priorities, patterns of working and perceptions of older people. The paper concludes by considering a potential way to merge territorial interests by reconfiguring the map of care around the older person.

Aged↗

Can brain-injured patients participate in an aerobic exercise programme during early inpatient rehabilitation?

OBJECTIVE: We investigated the capacity of brain-injured patients to participate in an aerobic exercise programme early after injury. DESIGN: Retrospective analysis of exercise achievements in patients participating in a randomized controlled trial. SETTING AND SUBJECTS: Ninety patients participated in an exercise training programme on a cycle ergometer at four inpatient neurological rehabilitation units for younger patients. At intake, impairments and function were rated on: Motricity Index, Ashworth Scale, Berg Balance Scale, Barthel Index and Functional Independence Measure. INTERVENTIONS: Patients cycled for up to 30 minutes three times weekly for 24-36 sessions over 12 weeks. MAIN OUTCOME MEASURES: Exercise performance was measured by: (a) number of sessions to achieve a cycling time of 30 minutes, (b) overall mean cycling time per session over 24 sessions and (c) mean time per session cycling at >60% of age predicted maximum heart rate (HR max) over 24 sessions. RESULTS: Fifty-five patients completed 24 sessions. Thirty-five withdrew, largely for logistic reasons, before completing training; they were significantly less disabled than the 55 who remained. Forty-four of the 55 patients trained for an average of at least 20 minutes per session, 18 training at >60% HR max for this time. There were no differences in performance on the three exercise parameters between two groups of patients with baseline Barthel scores of < or = 12 and > or = 13. CONCLUSIONS: Brain-injured patients with a range of disabilities have the capacity to participate in an exercise programme during early inpatient rehabilitation, though some may take longer to achieve adequate intensity of aerobic exercise.

Adolescent↗

Mathematical elements of attack risk analysis for mountain pine beetles.

Three different mathematical approaches are combined to develop a spatial framework in which risk of mountain pine beetle (MPB) attack on individual hosts may be assessed. A density-based partial differential equation model describes the dispersal and focusing behavior of MPB. A local projection onto a system of ordinary differential equations predicts the consequences of the density equations at individual hosts. The bifurcation diagram of these equations provides a natural division into categories of risk for each host. A stem-competition model links host vigor to stand age and demographics. Coupled together, these models illuminate spatial risk structures which may also shed light on the role of climatic variables in population outbreaks. Preliminary results suggest that stand microclimate has much greater influence on risk of attack than host vigor and stand age.

Animals↗

Measurement of excitation functions in the reactions 197Au(11C, xn)208-xAt using a radioactive 11C beam

A light-element radioactive ion-beam capability has been developed at the LBNL 88-Inch Cyclotron. The system is based on the coupled-cyclotrons method and utilizes short-lived species, e.g., 11C, 14O, 13N produced by (p,n) and (p,alpha) reactions at the LBNL Biomedical Isotope Facility Cyclotron. In a first experiment, 197Au(11C,xn)208-xAt excitation functions have been measured for energies ranging from the Coulomb barrier up to 110 MeV using a beam of 11C with intensities up to (1-2)x10(8) ions/sec on target. The results of this experiment are compared to measurements of 197Au(12C, xn)209-xAt excitation functions.

Journal Article↗

The effect of cocoa procyanidins on the transcription and secretion of interleukin 1 beta in peripheral blood mononuclear cells.

Recent data has demonstrated that cacao liquor polyphenols (procyanidins) have antioxidant activity, inhibit mRNA expression of interleukin-2 and are potent inhibitors of acute inflammation. Given the widespread ingestion of cocoa in many cultures, we investigated whether cocoa, in its isolated procyanidin fractions (monomer through decamer), would modulate synthesis of the pro-inflammatory cytokine, interleukin-1 beta. Both resting and phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) were investigated at the levels of transcription and protein secretion. Individual cocoa fractions were shown to augment constitutive IL-1 beta gene expression, although values varied between subjects. Interestingly, the smaller fractions of cocoa (monomer-tetramer) consistently reduced IL-1 beta expression of PHA-stimulated cells by 1-15%, while the larger oligomers (pentamer-decamer) increased expression by 4-52%. These data, observed at the transcription level, were reflected in protein levels in PHA-induced PBMC. The presence or absence of PHA did not alter the effects of the cocoa procyanidins with the exception of the pentamer. This study offers additional data for the consideration of the health-benefits of dietary polyphenols from a wide variety of foods, including those benefits associated specifically with cocoa and chocolate consumption.

Antioxidants↗