False-positive Epo test concerns unfounded.
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Erythropoietin↗
Biomedical subjects
Paul Scott
Publications and source records attributed to Paul Scott.
Evaluation of PCDD/F and dioxin-like PCB serum concentration data from the 2001-2002 National Health and Nutrition Examination Survey of the United States population.
We analyzed the weighted 2001-2002 National Health and Nutrition Examination Survey data to assess potential differences in mean total 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) TEQ between various groups of individuals and to determine serum reference concentrations for polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) in the general US population. Differences appeared to exist between female smokers and non-smokers and between non-Hispanic groups and all other races. Potential differences were also observed among the four age groups with an increasing trend in mean total TCDD TEQ with increasing age. Both age and gender appeared to confound the association between smoking status and total TCDD TEQ, dictating the need for further analysis. As anticipated, PCBs contributed appreciably to the total TCDD TEQ levels in the referent population and accounted for 38% to 41% of the total TEQ depending on age. Nearly 80% of the mean total TCDD TEQ was attributable to four PCDD/F congeners and three PCB congeners. In this analysis, two methods were used to assess samples where the concentrations were below the limits of detection (LODs), and this did not have significant impact on the mean total TCDD TEQ at the higher percentiles and for older individuals. Comparison of our results to those from a recent PCDD/F biomonitoring study indicates that the mean TCDD TEQ serum concentration of the individuals studied does not appear to be different from typical levels found in the general US population. Additionally, an assessment of data from the National Human Adipose Tissue Survey using our referent statistics shows that levels of these chemicals have been declining in the general population for at least two decades. The reference TEQs presented in this paper provide relevant, current data that can be used to evaluate biomonitoring results of individuals or groups exposed or potentially exposed to PCDD/Fs and PCBs above referent levels.
Adult↗
Age- and concentration-dependent elimination half-life of 2,3,7,8-tetrachlorodibenzo-p-dioxin in Seveso children.
OBJECTIVE: Pharmacokinetic and statistical analyses are reported to elucidate key variables affecting 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) elimination in children and adolescents. DESIGN: We used blood concentrations to calculate TCDD elimination half-life. Variables examined by statistical analysis include age, latency from exposure, sex, TCDD concentration and quantity in the body, severity of chloracne response, body mass index, and body fat mass. PARTICIPANTS: Blood was collected from 1976 to 1993 from residents of Seveso, Italy, who were < 18 years of age at the time of a nearby trichlorophenol reactor explosion in July 1976. RESULTS: TCDD half-life in persons < 18 years of age averaged 1.6 years while those > or =18 years of age averaged 3.2 years. Half-life is strongly associated with age, showing a cohort average increase of 0.12 year half-life per year of age or time since exposure. A significant concentration-dependency is also identified, showing shorter half-lives for TCDD concentrations > 400 ppt for children < 12 years of age and 700 ppt when including adults. Moderate correlations are also observed between half-life and body mass index, body fat mass, TCDD mass, and chloracne response. CONCLUSIONS: Children and adolescents have shorter TCDD half-lives and a slower rate of increase in half-life than adults, and this effect is augmented at higher body burdens. RELEVANCE: Modeling of TCDD blood concentrations or body burden in humans should take into account the markedly shorter elimination half-life observed in children and adolescents and concentration-dependent effects observed in persons > 400-700 ppt.
Adolescent↗
Disposable cleansing wipes.
With hospital cleanliness becoming a major issue over recent months, a great many campaigns are under way to improve cleaning levels in our hospitals. This article looks at the role of disposable wipes, both for patient skin hygiene and for hard-surface cleaning and disinfection, in keeping clinical areas clean and safe for patients.
Disinfection↗
Surveillance of HIV antiretroviral drug resistance in treated individuals in England: 1998-2000.
OBJECTIVES: To establish a surveillance programme for HIV drug resistance within the UK covering the years from 1998 to 2000, following the introduction of triple combination antiretroviral therapy. METHODS: Sentinel sites included large, medium sized and small clinical centres. Data were analysed until December 2000. RESULTS: Of nearly 300 samples tested, results from 91, 92 and 92 patients, respectively in 1998, 1999 and 2000, who were receiving HIV therapy with a viral load >2000 copies/mL, the majority had viruses with some degree of drug resistance. Overall, the presence of any resistance increased between 1998 and 1999, and fell again in 2000 (69% versus 88% versus 55%). However, major differences were observed between drug classes, such that non-nucleoside analogue reverse transcriptase inhibitor (NNRTI) resistance rose dramatically over the period studied. We show that this correlated with increased NNRTI prescribing. Furthermore, an overall increase in prevalence of viruses with resistance to one or more drugs within all three available classes was observed. A higher prevalence of drug resistance was observed in patients from smaller clinical centres. CONCLUSIONS: This is the first such sentinel surveillance dataset from the UK, and is unique in correlating these data with national antiretroviral prescribing patterns. Our findings are relevant to the increased transmission of HIV drug resistance observed over this period.
Anti-HIV Agents↗
Mucinous intestinal type adenocarcinoma of the sinonasal tract secondary to passive wood dust inhalation: case report.
A 76-year-old female patient with a mucinous intestinal type adenocarcinoma of the sinonasal tract is described. The probable aetiology of passive hard wood dust inhalation, investigations carried out and subsequent surgical treatment using a transfacial access approach and a temporoparietal fascial composite free flap in conjunction with free auricular cartilage are described.
Adenocarcinoma, Mucinous↗
What are theories for? Concept use throughout the continuum of dinosaur expertise.
Although it is now well established that object concepts are situated within broader systems of theoretical knowledge, it is less clear how theories influence the use of object concepts at various points throughout the continuum of expertise. Two studies were conducted to investigate the impact of specific theories (concerning dinosaurs) and overarching framework theories (of biology) on children's and adults' performance on categorization tasks involving familiar and less familiar concepts. Although expertise increased the quantity of deep feature knowledge possessed by children and increased their understanding of biologically adaptive relations among features, few aspects of children's performance generalized beyond highly familiar dinosaurs. Children's specific theories related to dinosaurs were empirically constrained and relatively dissociated from other types of biological knowledge. The interaction of specific concept knowledge with broader framework theories of biology throughout the continuum of expertise is considered.
Animals↗
Oral piercing and associated complications: two case reports.
These two cases, which presented in a three-month period to a Maxillofacial Surgery Department of a District General Hospital, demonstrate problems that can occur following oral piercing.
Adolescent↗
Characterisation of bradykinin B1 and B2 receptors using rat isolated vas deferens.
The actions of bradykinin and its metabolite des-Arg(9) bradykinin are mediated through activation of bradykinin B(2) and B(1) receptors, respectively. The aim of the present study was to characterize native bradykinin receptors focusing on induction and desensitization using rat isolated vas deferens. Tissues were mounted in organ baths for isometric recordings and neurogenically mediated contractions were evoked by electrical stimulation. Des-Arg(9) bradykinin enhanced the magnitude of the electrically evoked contractions and this effect (which was sensitive to blockade by the peptide bradykinin B(1) receptor selective antagonist B9858, Lys-Lys-(Hyp(3),Cpg(5),D-Tic(7),Cpg(8))des-Arg(9) bradykinin) was only observed following a pre-incubation period and was greatest following 5 h of pre-incubation. Bradykinin also potentiated neurogenically evoked contractions and this effect was sensitive to blockade by Hoe 140 (D-Arg(Hyp(3),Thi(5),D-Tic(7),Oic(8))bradykinin, a peptide bradykinin B(2) receptor antagonist) and was present without pre-incubation but was increased by pre-incubation and reached maximum at the 5-h incubation time point. Responses to bradykinin were larger than those to des-Arg(9) bradykinin. Bradykinin responses did not show desensitization on repeated agonist stimulation. These data confirm in rat isolated vas deferens bradykinin B(2), but not B(1), receptors are constitutively expressed, that both receptor populations are inducible and B(2) receptors do not exhibit desensitization.
Animals↗
The effect of diabetes on endothelin, interleukin-8 and vascular endothelial growth factor-mediated angiogenesis in rats.
In diabetes mellitus, there is a problem of both premature atherosclerosis as well as impaired collateralization. Studies were performed using the rat corneal angiogenesis model as a surrogate for collateralization to determine the effect of diabetes mellitus on endothelin (ET)-1, ET-3, vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8)-mediated angiogenesis. In an initial group of experiments, streptozotocin-induced diabetes resulted in impairment of ET-1-mediated angiogenesis from 69% to 32%, but was only impaired from 74% to 59% for ET-3. When rats were fluid-resuscitated, mortality fell, and the incidence of inhibition of angiogenesis decreased for ET-1, but was still at 47%. Inhibition of ET-3-mediated angiogenesis in fluid-resuscitated rats was essentially unaffected from 74% to 75%. Studies of VEGF and IL-8 in fluid-resuscitated rats demonstrated that VEGF-mediated angiogenesis was only inhibited from 49% to 45%, but there was inhibition of IL-8-mediated angiogenesis from 62% to 31%. We concluded that there may be two mechanisms by which ET-1-mediated corneal angiogenesis is inhibited: a decrease in intravascular volume and dynamic forces affecting angiogenesis, and a direct effect of diabetes on some aspect of cell growth or angiogenic process. Diabetes also appeared to inhibit IL-8-mediated angiogenesis, but had very little or no effect on ET-3- or VEGF-mediated angiogenesis.
Animals↗
Identifying soil cleanup criteria for dioxins in urban residential soils: how have 20 years of research and risk assessment experience affected the analysis?
This article reviews the scientific evidence and methodologies that have been used to assess the risks posed by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and presents a probabilistic analysis for identifying virtually safe concentrations of TCDD toxicity equivalents (TEQ) in residential soils. Updated data distributions that consider state-of-the-science cancer and noncancer toxicity criteria, child soil ingestion and dermal uptake, bioavailability in soil, and residential exposure duration are incorporated. The probabilistic analysis shows that the most sensitive determinants of dose and risk are childhood soil ingestion, exposure duration, and the selected TCDD cancer potency factor. It also shows that the cancer risk at 1 per 100,000 predicted more conservative (lower) soil criteria values than did the noncancer hazard (e.g., developmental and reproductive effects). In this analysis, acceptable or tolerable soil dioxin concentrations (TCDD TEQ) ranged from 0.4 to 5.5 ppb at the 95th percentile for cancer potency factors from 9600 to 156,000 (mg/kg/d)(-1) with site-specific adjustments not included. Various possible soil guidelines based on cancer and noncancer risks are presented and discussed. In the main, the current toxicology, epidemiology, and exposure assessment data indicate that the historical 1 ppb TEQ soil guidance value remains a reasonable screening value for most residential sites. This analysis provides risk managers with a thorough and transparent methodology, as well as a comprehensive information base, for making informed decisions about selecting soil cleanup values for PCDD/Fs in urban residential settings.
Biological Availability↗
Fluorescent-activated cell-sorting analysis of intracellular interferon-gamma and interleukin-4 in fresh and frozen human peripheral blood T-helper cells.
T-helper (Th) cells can be classified into at least three subsets based on their cytokine profiles: Th0, Th1, and Th2. The functional significance of each subset of Th cells can be determined in isolated human peripheral blood mononuclear cells (PBMC). Using two- or three-color cytometric detection of intracellular cytokines. These analyses have been limited by the requirement for fresh cells making sequential samples and longitudinal studies difficult. Cryopreservation of PBMC in liquid nitrogen for up to 1 year was evaluated to determine whether the Th1/Th2 ratio remained unchanged in cryopreserved lymphocytes. Aliquots of human PBMC from normal volunteers analyzed for activation using phorbol myristate acetate and evaluated using morphology showed that the surface marker expression was unchanged in fresh and frozen cells. Cytokine expression was measured using intracellular cytokine staining and three-color flow cytometric analysis. The percentages of cells producing interferon (IFN)-gamma or interleukin (IL)-4 were determined after 16 hours of phorbol myristate acetate and ionomycin stimulation in the presence of brefeldin A. No significant difference was found in cytokine production between fresh and frozen cells. The percentage of IFN-gamma and IL-4 producing CD3-positive fresh T cells was 19.2+/-5.8 percent and 0.9+/-0.4 percent vs. 17.6+/-0.75 percent and 0.9+/-0.3 percent, respectively, for frozen PBMC. The effects of thermal injury on the Th1/Th2 cytokine ratio and the development of hypertrophic scarring were then determined. Twelve burn patients examined 4 weeks postburn showed a significant shift in the Th1/Th2 ratio, compared with 13 normal human volunteers used as controls. IL-4 levels in the patient group were significantly higher than controls at 1 month postburn (12.7+/-2.6 percent vs. 3.9+/-0.5 percent, p<0.01) and IFN-gamma levels were significantly lower (9.3+/-1.7 percent vs. 15.3+/-2.3 percent, p<0.05). Thus, PBMC can be cryopreserved for up to 1 year, enabling investigation of chronologic changes in Th1/Th2 profiles. It is suggested that a "locked on" Th2 profile may contribute to the development of hypertrophic scarring after burn injury.
Adult↗
The buccal fat pad in the closure of oro-antral communications: an illustrated guide.
This article is intended as an illustrated, step-by-step guide in the use of the pedicled buccal fat pad in the closure of oro-antral communications. The advantages and disadvantages of its use are discussed, along with its basic anatomy.
Adipose Tissue↗