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S Black

Publications and source records attributed to S Black.

At least 19 recordsLinked to original sources
PubMed2006

Validity of age at menarche self-reported in adulthood.

OBJECTIVE: To test the validity of age at menarche self-reported in adulthood and examine whether socioeconomic position, education, experience of gynaecological events and psychological symptoms influence the accuracy of recall. DESIGN: Prospective birth cohort study. SETTING: England, Scotland and Wales. PARTICIPANTS: 1050 women from the Medical Research Council National Survey of Health and Development, with two measures of age at menarche, one recorded in adolescence and the other self-reported at age 48 years. RESULTS: By calculating the limits of agreement, kappa statistic and Pearson's correlation coefficients (r), we found that the validity of age at menarche self-reported in middle age compared with that recorded in adolescence was moderate (kappa = 0.35, r = 0.66, n = 1050). Validity was improved by categorising age at menarche into three groups: early, normal and late (kappa = 0.43). Agreement was influenced by educational level and having had a stillbirth or miscarriage. CONCLUSIONS: The level of validity shown in this study throws some doubt on whether it is justifiable to use age at menarche self-reported in middle age. It is likely to introduce error and bias, and researchers should be aware of these limitations and use such measures with caution.

Abortion, Spontaneous↗
PubMed2005

Naturally occurring radioactive material (NORM) from a former phosphoric acid processing plant.

In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by 238U and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (< or =8.8 Bq/g) of 238U were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (< or =11 Bq/g) of 226Ra were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution.

Calcium Sulfate↗
PubMed2004

Comparison of two major emergency department-based free-text chief-complaint coding systems.

INTRODUCTION: Emergency departments (EDs) using free-text chief-complaint data for syndromic surveillance face a unique challenge because a complaint might be described and coded in multiple ways. OBJECTIVE: Two major ED-based free-text chief-complaint coding systems were compared for agreement between free-text interpretation and syndrome coding. METHODS: Chief-complaint data from 21,736 patients at an urban ED were processed through both the New York City Department of Health and Mental Hygiene (DOHMH) syndrome coding system as modified by the Chicago Department of Public Health and the Real-Time Outbreak Detection System Complaint Coder (CoCo, version 2.1, University of Pittsburgh). To account for differences in each system's specified syndromes, relevant syndromes from the DOHMH system were collapsed into the corresponding CoCo categories so that a descriptive comparison could be made. DOHMH classifications were combined to match existing CoCo categories as follows: 1) vomit+diarrhea = Gastrointestinal; 2) cold+respiratory+asthma = Respiratory; 3) fevflu = Constitutional; 4) rash = Rash; 5) sepsis+other = Other, 6) unknown = Unknown. RESULTS: Overall agreement between DOHMH and CoCo syndrome coding was optimal (0.614 kappa). However, agreement between individual syndromes varied substantially. Rash and Respiratory had the highest agreement (0.711 and 0.594 kappa, respectively). Other and Constitutional had an intermediate level of agreement (0.453 and 0.419 kappa, respectively), but less than optimal agreement was identified for Gastrointestinal and Unknown (0.270 and 0.002 kappa, respectively). CONCLUSIONS: Although this analysis revealed optimal overall agreement between the two systems evaluated, substantial differences in classification schemes existed, highlighting the need for a consensus regarding chief-complaint classification.

Algorithms↗
PubMed2004

Structural brain abnormalities in multiple sclerosis patients with major depression.

OBJECTIVE: To assess the association between major depression and structural brain abnormalities in patients with multiple sclerosis (MS). METHODS: Two groups of patients with clinically definite MS were studied: 21 with Diagnostic and Statistical Manual of Mental Disorders (4th ed.)-defined major depression and 19 without. The groups did not differ on demographic, disease, or cognitive measures. All subjects underwent brain MRI. Tissue segmentation and regional brain masking were applied to the MRI data. RESULTS: Compared with the euthymic subjects, those with major depression had a greater T2-weighted lesion volume (p = 0.003) and more extensive T1-weighted lesion volume in the left medial inferior prefrontal cortex (p = 0.01) and less gray matter volume (p = 0.01) and more CSF volume in the left anterior temporal region (p = 0.005). A logistic regression analysis identified two independent predictors of depression: left medial inferior prefrontal cortex T2 lesion volume and left anterior temporal CSF volume. These variables accounted for 42% of the depression variance score. CONCLUSION: Whereas both lesion burden and atrophy are important in the pathogenesis of depression in MS, psychosocial influences should also be considered.

Adult↗
PubMed2004

[Clinical effectiveness of seven-valent pneumococcal conjugate vaccine (Prevenar) against invasive pneumococcal diseases: prospects for children in France].

A seven-valent pneumococcal polysaccharide-CRM197 carrier protein conjugate vaccine (PNC7V; Prevenar, Wyeth, Paris) targets the serotypes (belonging to serogroups 14, 6, 19, 18, 23, 9, and 4) most often responsible for invasive pneumococcal disease (IPD) among children. A randomized, controlled, double-masked study among 37,868 children in northern California (Northern California Kaiser Permanente, USA) provided a per protocol vaccine efficacy value of 97.7% against invasive pediatric IPD due to the vaccine serotypes. The PNC7V vaccine was registered by the European Agency for the Evaluation of Medicinal Products (EMEA) in October 2000; a favorable "Community Marketing Decision" under the Centralized Procedure was granted in February 2001. PNC7V was recommended for most infants by the Conseil Supérieur d'Hygiène Publique de France in March 2002, on the advice of the Comité Technique des Vaccinations, as S. pneumoniae in children less than 2 years of age is the primary cause of bacterial meningitis and of mortality associated with community-acquired bacterial infections. The theoretical coverage of the vaccine towards pneumococcal invasive disease in France is about 80%, which represents one of the best serotype coverage estimates in Europe, and vaccines serotypes account for 90% of penicillin-nonsusceptible strains. Distinctive characteristics in France in terms of epidemiology, life style, and therapeutic attitudes justify a precise follow up of the consequences of the vaccination on a national level during the coming years. Hence, surveillance programs have been established: (i) to ascertain the future impact of large-scale PNC7V vaccination on invasive pneumococcal disease incidence, (ii) to follow the evolution of carriage and ecology of the pneumococcus, and (iii) to establish an active "vaccinovigilance".

Female↗
PubMed2004

Medically recorded allergies and the risk of childhood acute lymphoblastic leukaemia.

Data on five allergic conditions were abstracted from the medical records of 180 cases of childhood acute lymphoblastic leukaemia (ALL) and 718 matched controls. Odds Ratios (OR) and 95% Confidence Intervals (CI) were estimated for composite variables and for individual allergies using conditional logistic regression modelling. Allergies were divided into late and early diagnoses (those made within the year before the matched case's ALL diagnosis and those made earlier, respectively). Among the early diagnoses, atopy or hives was significantly associated with ALL (OR=2.20; 95% CI: 1.16-4.16). Significant associations were found for late diagnoses of atopy or hives (OR=3.78; 95% CI: 1.00-14.29) and of asthma (OR=3.10; 95% CI: 1.39-6.95). None of the other allergic conditions were associated with ALL. These results are contrary to those of prior studies of childhood ALL and allergy.

Case-Control Studies↗
PubMed2004

Syncytial fusion of human trophoblast depends on caspase 8.

Differentiation of human placental villous trophoblast includes syncytial fusion of cytotrophoblast forming syncytiotrophoblast. Early stages of the apoptosis cascade were described to be involved in this differentiation process. We investigated the role of the initiator caspase 8 in syncytial fusion in vitro, cultivating placental villous explants with or without caspase 8 antisense oligonucleotides or peptide inhibitors for up to 120 h. Trophoblast fusion and differentiation were assessed by confocal microscopy, immunohistochemistry and Western blot analysis. Culture with caspase 8 antisense oligonucleotides or peptide inhibitors reduced the fusion of cytotrophoblast with the syncytiotrophoblast, and resulted in multilayered cytotrophoblast. Caspase 8 expression was suppressed by antisense oligonucleotides and caspase 8 activities were reduced by peptide inhibitors. The organic anion-transporter hOAT-4 normally expressed in the cytotrophoblast and transferred into the syncytiotrophoblast by syncytial fusion was retained in the cytotrophoblast due to lack of fusion. We conclude that expression and activity of caspase 8 is a prerequisite for differentiation and syncytial fusion of cytotrophoblast cells.

Apoptosis↗
PubMed2004

The emerging role of the emergency care practitioner.

OBJECTIVES: To examine the emerging role of the emergency care practitioner (ECP) with comparisons to paramedic practice. Key activities were identified of newly appointed ECPs using qualitative methodology and a qualitative and quantitative comparison of patient treatment was made. METHOD: A constructivist methodology taking account of stakeholder input and drawing upon the constant comparisons of different group's construction of reality. Four practitioners completed reflective patient case studies and adapted patient report forms, which were compared with a second case group of 11 paramedics. In addition individual and focus groups interviews were performed with key stakeholders. RESULTS: In the comparison between ECP and paramedic roles, 331 paramedic incidents were compared with 170 ECP reports. ECPs treated 28% of patients on scene compared with 18% by paramedics (p = 0.007). Fifty per cent of ECPs patients were conveyed compared with 64% of paramedics (p = 0.000). Analysis of the 269 reflective reports and 14 stakeholder interviews revealed four key themes. Firstly, ECPs had a beneficial impact on the deployment of resources, especially relating to non-conveyance. Secondly, their training and education improved their decision making repertoire and developed their confidence for a leadership role. Thirdly, inter-agency collaboration and cooperation was improved, and finally, care benefits were increased especially relating to immediacy of treatment and referral mechanisms. CONCLUSIONS: The results indicate that an investment in the ECP role could be beneficial, however, more work is required to evaluate the development of practice, the quality of care, and cost benefits.

Adolescent↗
PubMed2004

Quality assessments of HMO diagnosis databases used to monitor childhood vaccine safety.

OBJECTIVE: To assess the quality of automated diagnoses extracted from medical care databases by the Vaccine Safety Datalink (VSD) study. METHODS: Two methods are used to assess quality of VSD diagnosis data. The first method compares common automated and abstracted diagnostic categories ("outcomes") in 1-2% simple random samples of study populations. The second method estimates positive predictive values of automated diagnosis codes used to identify potential cases of rare conditions (e.g., acute ataxia) for inclusion in nested case-control medical record abstraction studies. RESULTS: There was good agreement (64-68%) between automated and abstracted outcomes in the 1-2% simple random samples at 3 of the 4 VSD sites and poor agreement (44%) at 1 site. Overall at 3 sites, 56% of children with automated cerebella ataxia codes (ICD-9 = 334) and 22% with "lack of coordination" codes (ICD-9 = 781.3) met objective clinical criteria for acute ataxia. CONCLUSIONS: The misclassification error rates for automated screening outcomes substantially reduce the power of screening analyses and limit usefulness of screening analyses to moderate to strong vaccine-outcome associations. Medical record verification of outcomes is needed for definitive assessments.

Child, Preschool↗
PubMed2003

A school-based randomized controlled trial of peer-led sex education in England.

This article discusses the design of an ongoing cluster-randomized trial comparing two forms of school-based sex education in terms of educational process and sexual health outcomes. Twenty-nine schools in southern England have been randomized to either peer-led sex education or to continue with their traditional teacher-led sex education. The primary objective is to determine which form of sex education is more effective in promoting young people's sexual health. The trial includes an unusually detailed evaluation of the process of sex education as well as the outcomes. The sex education programs were delivered in school to pupils ages 13-14 years who are being followed until ages 19-20. Major trial outcomes are unprotected sexual intercourse and regretted intercourse by age 16 and cumulative incidence of abortion by ages 19-20. We discuss the rationale behind various aspects of the design, including ethical issues and practical challenges of conducting a randomized trial in schools, data linkage for key outcomes to reduce bias, and integrating process and outcome measures to improve the interpretation of findings.

Adolescent↗
PubMed2003

Pre-eclampsia and maternal anaemia display reduced apoptosis and opposite invasive phenotypes of extravillous trophoblast.

During pregnancy extravillous trophoblast invades maternal uterine tissues and remodels spiral arteries. Maternal anaemia and early onset pre-eclampsia are associated with perturbed trophoblast biology. We systematically compared numerical density, invasive depth and apoptosis rates of extravillous trophoblast in uterine tissues taken from hysterectomies following Caesarean section after normal pregnancies (n=4) or pregnancies complicated by pre-eclampsia (n=5) or anaemia (n=6). Full thickness sections of the placental bed were studied by immunohistochemistry using anti-active caspase 3, anti-cytokeratin 7, anti-lamin B, M30, Mib-1, anti-PARP, and by the TUNEL assay. In normal pregnancy extravillous trophoblast invaded 2.04+/-0.19 mm (mean+/-SEM ) from the endometrial-myometrial border into the myometrium; in pre-eclampsia 0.67+/-0.14 mm (P< 0.01), and in anaemia 3.84+/-0.21 mm (P< 0.001). The endometrial trophoblast density in normal pregnancy was 2.44+/-0.37 cells per 60,000 microm(3), in pre-eclampsia was 1.04+/-0.15 (P< 0.01), and in anaemia was 3.10+/-0.32. The rate of apoptotic extravillous trophoblast (M30-positive) in the endometrium in normal pregnancy was 7.17+/-1.46 per cent, in pre-eclampsia 4.4+/-0.71, and in anaemia 2.1+/-0.42 (P< 0.01). Maternal anaemia leads to general tissue hypoxia throughout gestation. Increased invasive depth could be explained by hypoxia-stimulated mitosis and decreased apoptosis of extravillous trophoblast. Reduced trophoblast invasion in pre-eclampsia cannot be explained by higher rates of apoptosis.

Adult↗
PubMed2003

Effect of social exclusion on the risk of teenage pregnancy: development of hypotheses using baseline data from a randomised trial of sex education.

STUDY OBJECTIVE: The UK government argues that "social exclusion" increases risk of teenage pregnancy and that educational factors may be dimensions of such exclusion. The evidence cited by the government is limited to reporting that socioeconomic disadvantage and educational attainment influence risk. Evidence regarding young people's attitude to school is not cited, and there is a lack of research concerning the UK. This paper develops hypotheses on the relation between socioeconomic and educational dimensions of social exclusion, and risk of teenage pregnancy, by examining whether dislike of school and socioeconomic disadvantage are associated with cognitive/behavioural risk measures among 13/14 year olds in English schools. DESIGN: Analysis of data from the baseline survey of a study of sex education. SETTING AND PARTICIPANTS: 13/14 year old school students from south east England. MAIN RESULTS: The results indicate that socioeconomic disadvantage and dislike of school are associated with various risk factors, each with a different pattern. Those disliking school, despite having comparable knowledge to those liking school, were more likely to have sexual intercourse, expect sexual intercourse by age 16, and expect to be parents by the age of 20. For most associations, the crude odds ratios (ORs) and the ORs adjusted for the other exposure were similar, suggesting that inter-confounding between exposures was limited. CONCLUSIONS: It is hypothesised that in determining risk of teenage pregnancy, the two exposures are independent. Those disliking school might be at greater risk of teenage pregnancy because they are more likely to see teenage pregnancy as inevitable or positive.

Adolescent↗
PubMed2003

Is use of antiretroviral therapy among homosexual men associated with increased risk of transmission of HIV infection?

BACKGROUND/OBJECTIVE: There is concern that use of highly active antiretroviral therapy (HAART) may be linked to increased sexual risk behaviour among homosexual men. We investigated sexual risk behaviour in HIV positive homosexual men and the relation between use of HAART and risk of HIV transmission. METHODS: A cross sectional study of 420 HIV positive homosexual men attending a London outpatient clinic. Individual data were collected from computer assisted self interview, STI screening, and clinical and laboratory databases. RESULTS: Among all men, sexual behaviour associated with a high risk of HIV transmission was commonly reported. The most frequently reported type of partnership was casual partners only, and 22% reported unprotected anal intercourse with one or more new partners in the past month. Analysis of crude data showed that men on HAART had fewer sexual partners (median 9 versus 20, p=0.28), less unprotected anal intercourse (for example, 36% versus 27% had insertive unprotected anal intercourse with a new partner in the past year, p=0.03) and fewer acute sexually transmitted infections (33% versus 19%, p=0.004 in the past 12 months) than men not on HAART. Self assessed health status was similar between the two groups: 72% on HAART and 75% not on HAART rated their health as very or fairly good, (p=0.55). In multivariate analysis, differences in sexual risk behaviour between men on HAART and men not on HAART were attenuated by adjustment for age, time since HIV infection. CD4 count and self assessed health status. CONCLUSION: HIV positive homosexual men attending a London outpatient clinic commonly reported sexual behaviour with a high risk of HIV transmission. However, behavioural and clinical risk factors for HIV transmission were consistently lower in men on HAART than men not on HAART. Although use of HAART by homosexual men with generally good health is not associated with higher risk behaviours, effective risk reduction interventions targeting known HIV positive homosexual men are still urgently needed.

Adult↗
PubMed2003

Is the routine use of antibiotics justified in adult tonsillectomy?

Pain and secondary haemorrhage are the commonest complications of adult tonsillectomy, occurring mostly in the community. This is a randomized, double-blind, placebo-controlled, prospective trial of the effect of perioperative amoxycillin on these complications. The incidence and severity of post-operative haemorrhage was measured. For the first 10 post-operative days patients provided a linear pain score, a record of GP visits, and their use of additional antibiotics and analgesics. Of 95 patients considered: 23 suffered a secondary haemorrhage; 54 consulted their general practitioner (GP) because of pain; additional antibiotics were used by at least 31 and additional analgesics by at least 41. No significant differences were demonstrated between the active and placebo groups for any of these measures. This study demonstrates that secondary haemorrhage is common after adult tonsillectomy. Post-operative pain remains a major problem requiring frequent GP consultations. There appears to be no justification for the routine use of perioperative antibiotics.

Adolescent↗
PubMed2002

Single vs. dual vessel porcine extracorporeal liver perfusion.

BACKGROUND: The use of porcine extracorporeal liver perfusion (PECLP) to provide temporary hepatic support for patients in fulminant hepatic failure has been limited by the fact that individual perfusions can be sustained for only a few hours. Inadequate liver function and/or hemodynamic instability are the major contributing factors for early interruption of PECLP. Recent reports suggest that the choice of single (portal vein only) vs dual (portal vein and hepatic artery) vessel perfusion may influence the duration of perfusion. We hypothesize that PECLP with single vessel perfusion (SVP) is associated with worse liver function and greater hemodynamic instability than PECLP with dual vessel perfusion (DVP). MATERIALS AND METHODS: To eliminate the potentially confounding influences of liver failure and xenograft rejection, liver isografts procured from White-Landrace pig donors were perfused by either SVP or DVP via an extracorporeal circuit established with normal White-Landrace pig recipients. The function of perfused livers was evaluated by measuring production of bile and Factors V and VIII, clearance of ammonia and lactate, and extraction of O(2) at baseline and at 0, 1, 3, 6, 12, and 24 h after initiation of PECLP. The impact of PECLP on recipient hemodynamic status was assessed by monitoring BP, heart rate, urine output, O(2) saturation, etc. Among other parameters evaluated were serum albumin and total protein and hepatic release of IL-1beta and nitric oxide to assess their possible contributions to hemodynamic instability. RESULTS: DVP and SVP livers cleared ammonia and lactate similarly. Both approaches were associated with progressive hypoalbuminemia and hypoproteinemia. DVP livers produced more bile and Factor V and were associated with less recipient hypotension and IL-1beta and NO release than SVP livers. CONCLUSIONS: Livers with DVP function better than livers with SVP. The duration of PECLP can be limited by recipient hypotension, although this complication is less severe with DVP than with SVP.

Ammonia↗
PubMed2002

Is household antibiotic use a risk factor for antibiotic-resistant pneumococcal infection?

We used microbiology and pharmacy data from health-maintenance organizations to determine whether antibiotic use by a household member increases the risk of penicillin-non-susceptible pneumococcal disease. Though it has been well established that an individual's antibiotic use increases one's risk of antibiotic-resistant infection, it is unclear whether the risk is increased if a member of one's household is exposed to antibiotics. We therefore conducted a case-control study of patients enrolled in health maintenance organizations in Western Washington and Northern California. Cases were defined as individuals with penicillin-non-susceptible pneumococcal infection; controls were individuals with penicillin-susceptible pneumococcal infection. Socioeconomic variables were obtained by linking addresses with 1997 census block group data. One-hundred and thirty-four cases were compared with 798 controls. Individual antibiotic use prior to diagnosis increased the odds of penicillin non-susceptibility, with the strongest effect seen for beta-lactam use within 2 months (OR 1.8, 95% CI 1.2, 2.8). When household antibiotic use by persons other than the patient were considered, at 4 months prior to diagnosis there was a trend towards an association between penicillin non-susceptibility and beta-lactam antibiotic use, and a possible association in a small subgroup of patients with eye and ear isolates. However, no significant overall pattern of association was seen. We conclude that though antibiotic use of any kind within 2 months prior to diagnosis is associated with an increased risk of penicillin-non-susceptible pneumococcal disease, there is no significant overall pattern of association between household antibiotic use and penicillin-non-susceptible pneumococcal infection.

Adult↗
PubMed2002

Encoding and retrieval in aging and memory loss, a fMRI study.

Mild cognitive impairment (MCI) is a term for nondemented individuals with memory complaints and deficits greater than age-adjusted normal performance. Functional MRI (fMRI) may be a more sensitive method than other techniques to reveal functional abnormalities in individuals with MCI, only a proportion of whom progress to Alzheimer's disease (AD). fMRI was carried out while subjects (four MCI, five age-matched normal controls, and one AD) performed incidental encoding (deep and shallow) and recognition tasks for colored and black and white photographs contrasted to baseline fixation. fMRI revealed interesting dissociations between activation patterns and behavioral performance when comparing the MCI and AD to the NC.

Aging↗