Search PubMed⌕ Search

Biomedical subjects

M Sharp

Publications and source records attributed to M Sharp.

At least 19 recordsLinked to original sources
PubMed2001

Melting glaciers: a major source of persistent organochlorines to subalpine Bow Lake in Banff National Park, Canada.

Organochlorine pesticides and polychlorinated biphenyls (PCBs) are ubiquitous and persistent in the environment. They are known to concentrate in cold environments as a result of progressive evaporation from warm regions, and condensation in colder regions. In this study we show that melting glaciers supply 50 to 97% of the organochlorine inputs to a subalpine lake in Alberta, Canada, while contributing 73% of input water. Tritium analyses indicated that during the mid- to late summer warm period, at least 10% of the glacial melt originated from ice that was deposited in 1950-1970, when it was more contaminated with organochlorines. This finding suggests that climate warming may cause melting glaciers to become increasing sources of contaminants to freshwaters. Organochlorines from glacial streams were largely in dissolved form because the organic-poor glacial clays had a limited sorption capacity for the more hydrophobic chemicals.

Alberta↗
PubMed2001

Selenium status of cats in four regions of the world and comparison with reported incidence of hyperthyroidism in cats in those regions.

OBJECTIVE: To assess selenium (Se) status of cats in 4 regions of the world and to compare results for Se status with reported incidence of hyperthyroidism in cats in those regions. ANIMALS: 50 cats (30 from 2 regions with an allegedly high incidence of hyperthyroidism and 20 from 2 regions in which the disease is less commonly reported). PROCEDURE: Hematologic samples (heparinized whole blood, plasma, and RBC fractions) were obtained from 43 healthy euthyroid cats and 7 hyperthyroid cats. Plasma concentration of Se and activity of glutathione peroxidase (GPX) in whole blood and plasma were determined. RESULTS: Plasma concentration of Se and GPX activity in whole blood or plasma did not differ significantly among cats from the 4 regions. However, cats had a plasma concentration of Se that was approximately 5 times the concentration reported in rats and humans. The GPX activity in whole blood or plasma in cats generally was higher than values reported in rats or humans. CONCLUSIONS AND CLINICAL RELEVANCE: Cats have higher Se concentrations in plasma, compared with values for other species. However, Se status alone does not appear to affect the incidence of hyperthyroidism in cats. High Se concentrations may have implications for health of cats if such concentrations are influenced by the amount of that micronutrient included in diets.

Animals↗
PubMed2000

Gastroschisis: early enteral feeds may improve outcome.

OBJECTIVE: Population-based retrospective review of gastroschisis from 1986 to 1996. METHODS: This was a retrospective review of gastroschisis. Seventy cases were identified from the Birth Defects Registry of Western Australia (WA). Hospital medical records of live-born cases were reviewed. RESULTS: The live-born incidence of gastroschisis in WA was 2.1 per 10,000 live births for the period 1986-96. The incidence in mothers aged less than 20 years was 8.3-fold that of women aged over 30 years (P < 0.0001). The incidence rate for the period 1995-96 was over twice the rate for 1986-88. Age at first enteral feed was significantly related with length of hospital stay and duration of total parental nutrition (TPN). Each day delay in commencing enteral feed was associated with an increase in hospital stay of 1.05 days and an increase in TPN duration of 1.06 days. The method of delivery of the infant, age at repair, length of anaesthetic time, duration of postoperative paralysis and gestational age was not associated with length of stay or TPN duration. The data were divided into two cohorts: (i) 1986-90; and (ii) 1991-96. There was a statistically significant reduction in hospital stay from a geometric mean of 45.7 (1986-90) to 22.9 days (1991-96). CONCLUSIONS: Gastroschisis has a favourable outlook, with 89.7% survival of live births. Over the 10 year period studied, there has been a reduction in length of hospital stay and duration of TPN. The age at which the infant is first fed enteral feeds appears to be important in affecting the length of hospital stay and the duration of TPN, with delays associated with a longer hospital stay and longer TPN duration.

Adult↗
PubMed2000

Frequencies of memory T cells specific for varicella-zoster virus, herpes simplex virus, and cytomegalovirus by intracellular detection of cytokine expression.

Memory T cells specific for varicella-zoster virus (VZV), herpes simplex virus (HSV), and human cytomegalovirus (HCMV) were compared in immune adults by intracellular cytokine (ICC) detection. The mean percentages of CD4+ T cells were 0.11% for VZV and 0.22% for HSV by interferon (IFN)-gamma production; the frequency for HCMV was significantly higher at 1.21%. Percentages of VZV-, HSV-, and HCMV-specific CD4+ T cells were similar by use of tumor necrosis factor (TNF)-alpha. HCMV-stimulated CD8+ T cells produced IFN-gamma (1.11%) and TNF-alpha (1.71%); VZV- and HSV-specific CD8+ T cells were not detectable. VZV CD4+ T cell numbers were similar in young adults with natural or vaccine-induced immunity. VZV CD4+ T cells were significantly less frequent in older adults. Secondary varicella immunization did not increase VZV-specific CD4+ T cell frequencies by ICC assay. Numbers of memory T cells specific for herpesviruses may vary with sites of viral latency and with host age.

Adolescent↗
PubMed1999

Comorbidity of autistic spectrum disorders in children with Down syndrome.

The aim of the study was to identify the comorbidity of autistic spectrum disorders in a population of children with Down syndrome (DS). All children with DS within a defined population of South Birmingham were identified. The Asperger Syndrome Screening Questionnaire and the Child Autism Rating Scale were completed and diagnosis made according to ICD-10 criteria following interview and observation. Thirty-three of 58 identified children completed the measures, four of whom received a diagnosis of an autistic spectrum disorder. This is equivalent to a minimum comorbid rate of 7%. The questionnaire items concerning social withdrawal, restricted or repetitive interests, clumsiness, and unusual eye contact were associated with an autistic disorder. Of the remaining 29 participating children, 11 also displayed marked obsessional and ritualistic behaviours. The comorbid occurrence of autism and DS is at least 7%. It is important that these children are identified and receive appropriate education and support. A full assessment of social, language, and communication skills and behaviour is crucial, particularly in children with DS who appear different from other children with DS. Potential mechanisms accounting for this comorbidity are discussed.

Adolescent↗
PubMed1997

Gender differences in muscular strength: an allometric model approach.

Despite the fact that allometric modeling has been shown to be a more valid technique for group comparisons of body-size-adjusted muscular strength, no study to date has compared gender differences using absolute (no adjustment for body mass, BM), ratio (force/BM) and allometric (force/BMa) models for an active duty military population. Our purpose in this study was to use these models to compare gender differences in three strength tasks: maximal weight lifted to 152 cm height, maximal isometric force on an upright cable pull and maximal isometric handgrip force. Subjects were 989 and 987 active duty men and women, respectively, each of whom had fat-free mass (FFM) assessed hydrostatically. Results indicate that the ranges of gender difference in strength (%) were 57.9-103.7, 14.5-64.7 and 18.7-77.9 for absolute, ratio and allometrically scaled expressions, respectively, for BM and FFM. We conclude: 1. Men exhibit greater strength than women for all three indices regardless of model approach. 2. The magnitude of these differences is smaller when considering FFM rather than BM, but is larger when considering allometric vs. ratio models.

Adult↗
PubMed1995

Age-related differences in cell-mediated immunity to varicella-zoster virus among children and adults immunized with live attenuated varicella vaccine.

Live attenuated varicella vaccine elicits protection against varicella-zoster virus (VZV), but adults require two doses to achieve optimal seroconversion rates. To assess the potential role of cell-mediated immunity (CMI), T cell proliferation to VZV antigen was compared in children and adults. Mean stimulation indices (SI) in two cohorts of 39 children tested 6 weeks after vaccination were 28.6 +/- 6.21 and 22.1 +/- 3.84, whereas 20 adult vaccines had a mean SI of 9.1 +/- 0.99 (P = .04). Vaccinees had significant increases in CMI after a second dose of vaccine. At 1 year, VZV CMI was significantly lower in adults after two doses (10.0 +/- 1.13 vs. 15.6 +/- 1.77; P = .02), even though 82% of children received one dose. Limitations in the adult helper T cell response to VZV antigens may explain the need for booster doses to elicit effective immunity and the more frequent occurrence of varicella when adult vaccines are exposed to wild type virus.

Adolescent↗
PubMed1995

Chronic self-destructiveness and self-defeating personality: similarities and differences.

This study attempts to determine whether the Chronic Self-Destructiveness Scale (CSDS; Kelley, Byrne, et al., 1985) would be better described as a measure of impulsiveness or self-defeating behavior in the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., Rev. [DSM-III-R]; American Psychiatric Association, 1987) diagnostic sense. Subjects completed the CSDS, the Self-Defeating Scale (Schill, 1990), and measures of restraint, distress, and psychopathy. Based on the correlations among these scales, we suggest that the CSDS is better described as a measure of impulsiveness, poor judgment, and immediate gratification, rather than a measure of Self-Defeating Personality, which keeps the individual in a victim position.

Adolescent↗
PubMed1995

Self-defeating personality and depression: a closer look.

55 men and 55 women were given Schill's Self-defeating Personality Scale, a measure of Beck's cognitive triad, and a measure of the personality dimensions of sociotropy and autonomy. The more characteristics of self-defeating personality endorsed, the more negative were subjects' cognitions about themselves, the world, and the future. Self-defeating men and women scored higher on sociotropy (social dependence), suggesting threats to relationships may be an important source of depression for them. Self-defeating women also scored higher on the autonomy subscales, suggesting threats to their independence may be a source of depression as well. Implications for treatment were discussed.

Adolescent↗
PubMed1994

Self-defeating personality, depression, and pleasure from activities.

Prior research has shown people who scored high on a measure of self-defeating personality experienced less pleasure from various activities and accomplishments. The present research replicated the initial study with 55 men and 60 women, while controlling for the effects of depression. Analyses indicated that, while depression and self-defeating personality were related, depression was not the entire answer for why people with self-defeating personality derive less pleasure from activities.

Adult↗
PubMed1993

Pleasure from activities and self-defeating personality.

As predicted, people who scored higher on a measure of Self-defeating Personality reported experiencing less pleasure and enjoyment from individual and social activities as well as from personal accomplishments. The results were consistent with the idea that these people maintain a self-image of "loser" by minimizing or discounting positives in their lives. Results were also consistent with prior research showing a positive relationship between self-defeating personality and depressive affect.

Activities of Daily Living↗