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Biomedical subjects

E Collins

Publications and source records attributed to E Collins.

At least 19 recordsLinked to original sources
PubMed2006

Oral arginine attenuates the growth hormone response to resistance exercise.

This study investigated the combined effect of resistance exercise and arginine ingestion on spontaneous growth hormone (GH) release. Eight healthy male subjects were studied randomly on four separate occasions [placebo, arginine (Arg), placebo + exercise (Ex), arginine + exercise (Arg+Ex)]. Subjects had blood sampled every 10 min for 3.5 h. After baseline sampling (30 min), subjects ingested a 7-g dose of arginine or placebo (blinded, randomly assigned). On the exercise days, the subject performed 3 sets of 9 exercises, 10 repetitions at 80% one repetition maximum. Resting GH concentrations were similar on each study day. Integrated GH area under the curve was significantly higher on the Ex day (508.7 +/- 169.6 min.ng/ml; P < 0.05) than on any of the other study days. Arg+Ex (260.5 +/- 76.8 min.ng/ml) resulted in a greater response than the placebo day but not significantly greater than the Arg day. The GH half-life and half duration were not influenced by the stimulus administered. The GH secretory burst mass was larger, but not significantly, on the Arg, Ex, and Arg+Ex day than the placebo day. Endogenous GH production rate (Ex > Arg+Ex > Arg > placebo) was greater on the Ex and Arg+Ex day than on the placebo day (P < 0.05) but there were no differences between the Ex and Arg+Ex day. Oral arginine alone (7 g) stimulated GH release, but a greater GH response was seen with exercise alone. The combined effect of arginine before exercise attenuates the GH response. Autonegative feedback possibly causes a refractory period such that when the two stimuli are presented there will be suppression of the somatotrope.

Administration, Oral↗
PubMed2005

Alkaptonuric ochronosis: a case report.

Alkaptonuric ochronosis is a rare autosomal recessive metabolic disorder resulting in a deficiency of homogentisic acid oxidase (alkaptonuria). Ultimately, this enzyme deficiency enables homogentisic acid to accumulate, become polymerized, and be systemically deposited within various tissues of the body (ochronosis). As the disease progresses, tissue deposition of polymerized homogentisic acid eventually will lead to the progressive degeneration of all affected body systems. There is no definitive cure for alkaptonuric ochronosis, and treatment is aimed at controlling and ameliorating symptoms. Multiple systemic complications occur as a result of alkaptonuric ochronosis. In the skeletal system, cervical, thoracic and lumbosacral degenerative disk disease develops, as do widespread arthritic changes in peripheral and weight-bearing joints. In the respiratory system, dyspnea can develop owing to limited chest excursion as a result of stiffening of cartilage in the chest wall. In the cardiovascular system, coronary and valvular calcification frequently occurs. In the genitourinary system, calculi formation and urine discoloration are chief manifestations. This case report describes a 63-year-old man with alkaptonuric ochronosis who sustained a stress fracture of the left femoral neck, necessitating surgical repair, which was done without complications. An overview of alkaptonuric ochronosis is presented, and anesthetic implications are discussed.

Alkaptonuria↗
PubMed2002

Topology of electronic charge density and energetics of planar faults in fcc metals.

Using ab initio calculations we have studied the energetics and the evolution of the electronic charge density with shear in three fcc metals exhibiting different deformation properties, aluminum, silver, and iridium. The charge redistribution described by the change in character of specific charge density critical points (cps), is ascertained from the values of the charge density, rho(0), and its three principal curvatures, rho( parallel parallel), rho(hh), and rho(vv), respectively. The change in character of cps correlates with the energetics. For all three metals, rho(hh) vanishes near the unstable stacking configuration. The symmetry or asymmetry of the charge redistribution, measured by rho(hh)/rho(vv), may be an important factor determining stacking fault energies.

Journal Article↗
PubMed2001

Immigrant nurses' experience of racism.

PURPOSE: To document and describe the experiences of immigrant nurses of colour who have filed grievances concerning their employers' discriminatory practices; and to solicit their views of existing policies and recommendations for equity in professional life. DESIGN AND METHODS: In this descriptive, exploratory study nine immigrant nurses of colour in Ontario, Canada, were interviewed between 1997 and 1998. Data were collected through face-to-face interviews and in focus groups. The discourse theory and methods of van Dijk and Essed were used to analyse the qualitative data. FINDINGS: Recurring themes were: (a) being marginalized and acknowledging and naming the racist experiences; (b) experiencing physical stress and emotional pain; (c) strategizing to cope and survive; (d) recommending policy changes. CONCLUSIONS: All nurses interviewed had experienced reprisals as a result of complaining or filing grievances and unfairness was encountered in the redress process itself. Participants recommended policy initiatives to ensure equity and fair practices in the nursing profession.

Emigration and Immigration↗
PubMed2001

Evaluation of a PCR/DNA probe colorimetric membrane assay for identification of Campylobacter spp. in human stool specimens.

DNA was extracted from 50 human stool specimens using the QIAamp DNA stool minikit. PCR amplification was followed by post-PCR hybridization to DNA probes specific for the Campylobacter genus, Campylobacter jejuni, and Campylobacter coli in a colorimetric membrane assay. Thirty-two of 38 culture-positive specimens were PCR/DNA probe positive for C. jejuni. The assay is rapid and simple and can be applied to stool specimens for the detection of Campylobacter.

Campylobacter↗
PubMed2001

Evaluation of methods for detection of toxins in specimens of feces submitted for diagnosis of Clostridium difficile-associated diarrhea.

Clostridium difficile is the principal pathogen associated with hospital-acquired acute diarrheal disease. We have evaluated the performances of six approaches for diagnosis of C. difficile-associated diarrhea (CDAD). Consecutive stool specimens (n = 200) from 133 patients were examined by cytotoxin assay, by culture of C. difficile on cycloserine-cefoxitin-fructose agar, and by toxin detection using four rapid immunoassay systems (Oxoid Toxin A test, ImmunoCard Toxin A test, TechLab Tox A/B II test, and Premier Toxins A&B test). A diagnosis of CDAD was established for 35 (27%) patients (representing 29% of specimens). The adjusted sensitivity and specificity of the methods were, respectively, 98 and 99% for the cytotoxin assay, 54 and 99% for ImmunoCard, 50 and 98% for Oxoid, 79 and 98% for TechLab, 80 and 98% for Premier, and 57 and 100% for culture. The TechLab and Premier assays are acceptable tests for diagnosis of CDAD but are not equivalent to the cytotoxin assay.

Adult↗
PubMed2000

Anhydride modified cantharidin analogues: synthesis, inhibition of protein phosphatases 1 and 2A and anticancer activity.

Two series of anhydride modified cantharidin analogues were synthesised and screened for their phosphatase inhibition (PP1 and PP2A) and cytotoxicity in various cancer cell lines (Ovarian A2780, ADDP; Osteosarcoma 143B; and Colon HCT116 and HT29). One series was synthesised by a novel, high yielding one-pot hydrogenation-ring-opening-esterification procedure, the other by acid catalysed acetal formation. Analogues 5-7 and 9 displayed moderate PP2A selectivity (ca. 5- to 20-fold) and inhibition typically in the low microM range (comparable, in some cases to cantharidin). The anticancer activity of these analogues varied with the cell line under study; however, many of them showed selective cytotoxicity for the colon tumour cell lines.

Anhydrides↗
PubMed2000

How do general practitioners select antidepressants for depressed elderly people?

This study aimed to identify factors predicting general practitioner's (GPs) choice of which antidepressant to prescribe for depression in the elderly, using a postal questionnaire survey based on three clinical case vignettes. The main outcome measure was the GP's primary reason for selection of an antidepressant. GPs prescribing SSRIs gave 'few side effects' and 'safer in overdose' as the most important reasons for choosing the antidepressant. Older GPs were more likely to use unmodified tricyclics, and selected drugs based on their knowledge and experience in use of the drug. Cost was rarely a primary consideration. Educational programmes should address the reluctance by some GPs to use new or unfamiliar medications and highlight issues relating to side-effects and drug safety.

Adult↗
PubMed2000

Hepatitis C in injecting drug-using women during and after pregnancy.

BACKGROUND: A high proportion of female injecting drug users (IDU) have evidence of hepatitis C virus (HCV) infection. We undertook a prospective study of patients attending a clinic for pregnant IDU to determine the impact of pregnancy on the course of HCV infection and whether pregnancy is affected by HCV infection. METHODS: One hundred and thirty-one IDU were recruited and followed up with liver function tests, HCV serology and HCV-RNA tests. RESULTS: Of 131 patients, 125 had HCV antibodies (anti-HCV positive) at delivery, and of these 62% were HCV-RNA positive. The anti-HCV-negative women were younger and had a shorter duration of drug use than the anti-HCV-positive women. There were no differences between viraemic and non-viraemic women with respect to age, ethnicity, duration of injecting drug use, methadone maintenance dose, hepatitis B exposure or reported high-risk behaviour. Alanine aminotransferase (ALT) levels were higher and the proportion with ALT > 55 IU/L higher in viraemic women. Viraemia persisted in all 55 women who were viraemic at term. Eleven had an ALT flare post-partum that was unrelated to viral load and was clinically unsuspected. Four had concurrent elevated gamma-glutamyltranspeptidase and were considered to be drinking alcohol at hazardous levels. Four of 23 women who were HCV-RNA negative at term became positive during follow up. CONCLUSIONS: Pregnancy does not adversely affect the course of hepatitis C. A modest rebound in ALT levels, but not HCV-RNA, occurs after delivery in some viraemic women. This supports the theory that immune mechanisms rather than direct viral cytopathology are involved in hepatocyte injury during HCV infection. Hepatitis C infection did not influence pregnancy complications and outcomes.

Adult↗
PubMed2000

Mechanism of relaxations to dendroaspis natriuretic peptide in canine coronary arteries.

Experiments were designed to determine mechanisms by which Dendroaspis natriuretic peptide (DNP) causes relaxations in coronary arteries. Rings of canine left circumflex artery with and without endothelium were suspended in organ chambers filled with Krebs-Ringer bicarbonate solution (37 degrees C, bubbled with 95% O2/5% CO2). Concentration-response curves to DNP (10(-10) to 3 x 10(-7) M) were obtained in arteries contracted with prostaglandin (PGF(2alpha), 2 x 10(-6) M), either in the absence or the presence of C-ANP (10(-6) M) to inhibit natriuretic clearance receptors; indomethacin to inhibit cyclooxygenase (INDO, 10(-5) M), N(G)-monomethyl-L-arginine to inhibit production of nitric oxide (L-NMMA; 10(-4) M), HS-142-1 to inhibit particulate guanylate cyclase (10(-5) M); 1H-[1,2,4]oxadiazolo-[4,3-alpha]quinoxalin-1-one to inhibit soluble guanylate cyclase (ODQ; 10(-5) M), or tetraethylammonium to inhibit potassium channels (TEA; 10(-3) or 10(-2) M). Relaxations to DNP were greater in rings with than in those without endothelium. C-ANP significantly attenuated relaxations to DNP only in rings with endothelium. HS-146-1 but not INDO, L-NMMA, ODQ, and TEA significantly reduced relaxations to DNP in rings with and without endothelium contracted with PGF(2alpha). These results suggest that the endothelium augments inhibitory effects of DNP and that natriuretic clearance receptors mediate this component of the response to DNP in canine coronary arteries. In addition, relaxations to DNP in canine arterial smooth muscle involve activation of particulate guanylate cyclase but not hyperpolarization.

Animals↗
PubMed2000

Psychosocial impact of the lipodystrophy syndrome in HIV infection.

Lipodystrophy is a poorly understood condition associated with antiretroviral therapy in HIV infection. The symptoms may include some combination of central fat accumulation, peripheral fat depletion, and metabolic disturbance. A qualitative survey of 33 HIV-infected heterosexual women and gay men with lipodystrophy assessed psychosocial impact and effect on quality of life. Dominant themes included erosion of self-image and self-esteem, problems in social and sexual relations, threats to locus of control, forced HIV disclosure, and demoralization and depression. Another theme was clinicians' minimization of the importance of lipodystrophy. Further research is required to fully understand the psychosocial impact of lipodystrophy and to develop strategies that help individuals cope.

Adult↗
PubMed1999

Localization of a candidate surfactant convertase to type II cells, macrophages, and surfactant subfractions.

Pulmonary surfactant exists in the alveolus in several distinct subtypes that differ in their morphology, composition, and surface activity. Experiments by others have implicated a serine hydrolase in the production of the inactive small vesicular subtype of surfactant (N. J. Gross and R. M. Schultz. Biochim. Biophys. Acta 1044: 222-230, 1990). Our laboratory recently identified this enzyme in the rat as the serine carboxylesterase ES-2 [F. Barr, H. Clark, and S. Hawgood. Am. J. Physiol. 274 (Lung Cell. Mol. Physiol. 18): L404-L410, 1998]. In the present study, we determined the cellular sites of expression of ES-2 in rat lung using a digoxygenin-labeled ES-2 riboprobe. ES-2 mRNA was localized to type II cells and alveolar macrophages but not to Clara cells. Using a specific ES-2 antibody, we determined the protein distribution of ES-2 in the lung by immunohistochemistry, and it was found to be consistent with the sites of mRNA expression. Most of the ES-2 in rat bronchoalveolar lavage is in the surfactant-depleted supernatant, but ES-2 was also consistently localized to the small vesicular surfactant subfraction presumed to form as a consequence of conversion activity. These results are consistent with a role for endogenous lung ES-2 in surfactant metabolism.

Animals↗
PubMed1999

Mechanical distention modulates alveolar epithelial cell phenotypic expression by transcriptional regulation.

The development of a normal pulmonary alveolar epithelium, essential for gas exchange, is critical for the successful adaptation to extrauterine life. From observations of natural and experimental developmental abnormalities, it has been hypothesized that mechanical factors may play a role in regulating differentiation of the pulmonary alveolar epithelium. To test this hypothesis directly, we have investigated the in vitro effects of mechanical distention on the expression of specific markers for the type I and type II cell phenotypes. Fetal rat lung (18-d) explants were mechanically distended in culture for 18 h. Mechanical distention caused an increase in RTI 40 messenger RNA (mRNA), a marker of the type I cell phenotype, of 10.6 times (n = 3, P < 0.05) that of undistended controls. In contrast, mechanical distention resulted in a decrease in mRNA content of two markers of the type II cell phenotype, surfactant protein (SP)-B and SP-C. SP-B was reduced to 10 +/- 9% (n = 3, P < 0.005) and of SP-C to 12 +/- 7% (n = 3, P < 0.0001) of undistended controls. Mechanical distention had no effect on content of mRNA for SP-A or 18S ribosomal RNA. Examined by nuclear run-on assays, mechanical distention caused changes in transcriptional rates of RTI 40, SP-B, and SP-C. These data show that mechanical distention stimulates expression of a type I cell marker and inhibits expression of markers for the type II phenotype; these effects occur at least in part at the transcriptional level. These studies support the hypothesis that mechanical distention of fetal lung tissue stimulates expression of the type I cell phenotype and inhibits expression of the type II phenotype.

Animals↗
PubMed1998

Developmental regulation of protein phosphatase types 1 and 2A in post-hatch chicken brain.

The activity and subcellular distribution of protein phosphatases 1 and 2A were measured in chicken forebrain and cerebellum during post-hatch development. At all post-hatch ages, a large proportion of PP1 and PP2A was membrane bound and these enzymes were less active than their cytosolic counterparts. The protein concentration of PP1 in the membranes increased 40% between 2 and 14 days and a further 60% between 14 days and adult, whereas the PP1 enzyme activity in the membranes progressively decreased. In contrast to PP1, the protein concentration of PP2A remained constant in all fractions during post-hatch development, and the enzyme activity of PP2A did not change except for a decrease in the membrane-bound activity between 2 and 14 days. These results show that the subcellular distribution and activity of PP1 is selectively regulated during post-hatch development and that membrane association and inactivation of PP1 are independent events.

Aging↗
PubMed1998

Optimization of sacral ventral root stimulation following SCI: two case reports with six-month follow-up.

Sacral ventral root stimulation in conjunction with sacral dorsal rhizotomy has been effective in promoting voiding in individuals with upper-motor-neuron spinal cord injury. We report on two patients who had variable voiding responses to stimulation during the first six months after electrode implantation. We used videourodynamic records and daily voiding records to characterize their voiding difficulties. Different methods were used to improve voiding, including seating adjustments and changes in stimulation parameters. The first patient was unable to empty his bladder on a regular basis with stimulation using 24 pulses per sec stimulating frequency for the first two months after implantation. Voiding was substantially improved by using 35 pulses per sec. At the end of six months, he is regularly emptying his bladder with stimulation and is on an every-second-day bowel program. However, his bowel program has been irregular. The second patient had very good voiding when stimulation was applied in bed, but he had poor voiding with high residual volumes when sitting in his wheelchair. Voiding was improved when he used a wheelchair cushion that was cut out in the back or lifted his buttocks off the chair. These procedures appeared to reduce perineal pressures. This patient has bowel care on alternate days and his bowel care time has been reduced following implantation of the device. Neither of the patients experienced an erection with the device. Both patients feel positive about their implant experience.

Electric Stimulation Therapy↗
PubMed1997

Does a teaching programme improve general practitioners' management of depression in the elderly?

General Practitioners have a central role to play in the management of depression in their older patients. However, studies suggest that GPs tend to underdiagnose and undermanage depression in this age group. Continuing Medical Education is an important part of helping GPs keep up to date and improve their practice. We set out to see what effect a half a day postgraduate training course had on the views and knowledge of a group of local GPs on the management of depression in the elderly. Twenty-one general practitioners attended the course and of these fifteen completed a questionnaire with clinical vignettes before and six weeks after the course. Analysis of the questionnaire and vignette data showed significant improvements in a number of areas: in particular, GPs' knowledge about antidepressant treatment increased, as did their preference for cognitive behavioural therapy out of a range of psychological treatments. This study indicates that a teaching package on depression in the elderly can improve general practitioner's management knowledge. It also suggests that old age psychiatrists can play an important part in the education of their GP colleagues. Nevertheless, further studies are needed to ensure that educational programmes make an effective impact on the underdiagnosis and undertreatment of depression in the elderly.

Age Factors↗