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Biomedical subjects

C Hodgson

Publications and source records attributed to C Hodgson.

At least 19 recordsLinked to original sources
PubMed2006

Creatine supplementation, sleep deprivation, cortisol, melatonin and behavior.

The effect of creatine supplementation and sleep deprivation, with intermittent moderate-intensity exercise, on cognitive and psychomotor performance, mood state, effort and salivary concentrations of cortisol and melatonin were examined. Subjects were divided into a creatine supplementation group and a placebo group. They took 5 g of creatine monohydrate or a placebo, dependent on their group, four times a day for 7 days immediately prior to the experiment. They undertook tests examining central executive functioning, short-term memory, choice reaction time, balance, mood state and effort at baseline and following 18-, 24- and 36-h sleep deprivation, with moderate intermittent exercise. Saliva samples were taken prior to each set of tests. A group x time analysis of covariance, with baseline performance the covariate, showed that the creatine group performed significantly (p < 0.05) better than the placebo group on the central executive task but only at 36 h. The creatine group demonstrated a significant (p < 0.01) linear improvement in performance of the central executive task throughout the experiment, while the placebo group showed no significant effects. There were no significant differences between the groups for any of the other variables. A significant (p < 0.001) main effect of time was found for the balance test with a linear improvement being registered. Cortisol concentrations on Day 1 were significantly (p < 0.01) higher than on Day 2. Mood significantly (p < 0.001) deteriorated up to 24 h with no change from 24 to 36 h. Effort at baseline was significantly (p < 0.01) lower than in the other conditions. It was concluded that, during sleep deprivation with moderate-intensity exercise, creatine supplementation only affects performance of complex central executive tasks.

Adult↗
PubMed2006

Effect of creatine supplementation and sleep deprivation, with mild exercise, on cognitive and psychomotor performance, mood state, and plasma concentrations of catecholamines and cortisol.

RATIONALE: Sleep deprivation has a negative effect on cognitive and psychomotor performance and mood state, partially due to decreases in creatine levels in the brain. Therefore, creatine supplementation should lessen the negative effects of sleep deprivation. OBJECTIVES: The objective of this study was to examine the effect of creatine supplementation and sleep deprivation, with mild exercise, on cognitive and psychomotor performance, mood state, and plasma concentrations of catecholamines and cortisol. METHOD: Subjects were divided into a creatine group (n=10) and a placebo group (n=9). They took 5 g of creatine monohydrate or a placebo, dependent on their group, four times a time a day for 7 days, immediately prior to the experiment. The study was double blind. Subjects undertook tests of random movement generation (RMG), verbal and spatial recall, choice reaction time, static balance and mood state pre-test (0 h), after 6, 12 and 24 h of sleep deprivation, with intermittent exercise. They were tested for plasma concentrations of catecholamines and cortisol at 0 and 24 h. RESULTS: At 24 h, the creatine group demonstrated significantly less change in performance from 0 h (delta) in RMG, choice reaction time, balance and mood state. There were no significant differences between groups in plasma concentrations of catecholamines and cortisol. Norepinephrine and dopamine concentrations were significantly higher at 24 h than 0 h, but cortisol were lower. CONCLUSIONS: Following 24-h sleep deprivation, creatine supplementation had a positive effect on mood state and tasks that place a heavy stress on the prefrontal cortex.

Adult↗
PubMed2002

Vocal characteristics in pre-adolescent and adolescent children: a longitudinal study.

A number of cross-sectional studies have been reported for the fundamental frequency and formant frequency data in the voices of a group of 20 pre-adolescent children aged between 6 and 10 years (Whiteside, S P, Hodgson, C. Acoustic characteristics in 6-10-year old children's voices: some preliminary findings, Log Phon Vocol 1999; 24: 6-13, Whiteside, SP, Hodgson, C. Some acoustic characteristics in the voices of 6-10-year-old children and adults: a comparative sex and developmental perspective, Log Phon Vocol 2000; 25: 122-132). About 15 of the children who participated in these earlier studies, participated in a follow-up study approximately 42 months later. Their speech data were recorded and analysed acoustically to investigate longitudinal patterns of development in their voices by examining data for fundamental frequency and the first three formant frequencies of a phrase final vowel. Data obtained from this follow-up study (Time 2) were compared with earlier corresponding data (Time 1). The findings of this study indicated that there was evidence for maturation in the voice parameters of all subjects between Time 1 and 2, with changes being observed for the majority of comparisons for parameters, across age and sex. In addition there was also evidence of individual differences in the maturational patterns which were observed. These individual differences highlight the degree of variation which occurs in the developmental changes of voice characteristics.

Adolescent↗
PubMed2001

Local lung responses following local lung challenge with recombinant lungworm antigen in systemically sensitized sheep.

BACKGROUND: Chronic mast cell-mediated inflammation may contribute significantly towards the extensive tissue remodelling that is a feature of lungworm infection in ruminants. Understanding the factors that control tissue remodelling is a necessary step toward effective management and treatment of conditions that feature such pathology. OBJECTIVE: We sought to define in a novel ovine model system, the cellular, immune and mast cell phenotypic events that occur following local lung challenge with a recombinant protein antigen, DvA-1, derived from the ruminant lungworm nematode, Dictyocaulus viviparus. METHODS: Two spatially disparate lung segments in systemically sensitized sheep were challenged on three occasions with DvA-1 (3xDVA) and two further segments were challenged with saline (3xSAL). Two months after the third challenge, one of the two segments previously repeatedly challenged with DvA-1 was challenged again with DvA-1 (3xDVA:DVA) whilst the other was challenged with saline (3xDVA:SAL). A similar protocol was followed with the saline challenged segments (3xSAL:SAL and 3xSAL:DVA). Bronchoalveolar lavage fluid (BALF) (n = 16) and tissue (n = 3) were collected after the last challenge. RESULTS: Cellular changes 24 h after the fourth challenge were characterized by an increase in the absolute numbers of neutrophils and eosinophils in BALF from 3xDVA:DVA and 3xSAL:DVA segments. Local antibody production was implied through increased levels of antibody in both 3xDVA:DVA and 3xDVA:SAL segments, with the latter being unaffected by inflammation. Levels of active transforming growth factor beta-1 (TGF-beta(1)) were significantly increased in 3xDVA:SAL segments and a trend towards an increase was apparent in 3xDVA:DVA segments. Total TGF-beta1 levels were significantly correlated with eosinophil counts in all except the 3xDVA:SAL segments. Such changes in the bronchoalveolar space were complemented by increased ratios of sheep mast cell proteinase-1 expressing cells and tryptase expressing cells, to toluidine blue positive cells in airways from 3xDVA:DVA segments. CONCLUSION: Mast cell phenotypic events occurring as a consequence of antigen challenge were limited to segments in which changes in BALF were characterized by neutrophil influx and increased local antibody production.

Animals↗
PubMed2000

DNA dose and sequence dependence in sperm-mediated gene transfer.

We have tested three parameters in sperm-mediated gene transfer assays with mice and pigs: (i) the epididymal versus ejaculated origin of sperm cells, (ii) the primary structure, and (iii) the amount of the challenging foreign DNA. We have found that the pVLCNhGH construct, of retrotransposon origin, causes a massive embryo lethality and yet increases the yield of genetic transformation among born animals of both species compared to viral constructs. Arrest of embryonic development is a DNA dose-dependent effect, which is observed with high DNA doses, while lower doses are compatible with development. Finally, the overall efficiency of sperm-mediated gene transfer is higher when ejaculated, versus epididymal, spermatozoa are used. We suggest that this difference is related to the highly efficient apoptotic response in epididymal compared to ejaculated spermatozoa, triggered by the interaction of exogenous DNA molecules with the sperm membrane.

Animals↗
PubMed2000

Some acoustic characteristics in the voices of 6- to 10-year-old children and adults: a comparative sex and developmental perspective.

This study is a follow-up investigation of some of the acoustic characteristics reported for a group of twenty 6-, 8- and 10-year-old children's voices (Whiteside SP, Hodgson C. Log Phon Vocol 1999; 24: 6-13) and compares the data of these children with data from a group of nine adults. The acoustic characteristics for both the children and the adults were examined as a function of age and sex. Fundamental frequency (F0) and the standard deviation (SD) of F0 were investigated for the entire duration of a phrase-final vowel. In addition, the first three formant frequencies of the midpoints for the phrase-final vowel were also investigated, with reference to phonetic context. All acoustic parameters were investigated by examining the age, sex and context-determined differences. Results indicated significant age differences for all acoustic parameters investigated, which were characterized by a general decrease in the frequency values of parameters with increasing age. In addition, significant sex differences were found for all parameters, with the females generally having higher formant frequency values than their male peers across all ages. Significant phonetic context differences were only found for the second formant frequency, with formant values being highest for the context "jar" and lowest for the context "bar". No significant interactions were found for age-by-context, sex-by-context or age-by-sex-context comparisons. Relative formant frequency differences were also examined using Fant's Kn factor, by considering sex-, age- and context-linked patterns. The data also provided some evidence for parallel developmental patterns in the different phonetic contexts of a phrase-final vowel. Furthermore, the results showed that there was some evidence of all three types of the aforementioned patterns in addition to phonetic context-determined changes in K2 factor values. The results reported here, therefore, provide further evidence for age- and sex-linked differences in the patterns of development and maturation of the vocal apparatus.

Adult↗
PubMed2000

An investigation of the early effects of manual lung hyperinflation in critically ill patients.

This prospective within-group multicentre study was designed to assess the safety and short-term effectiveness of manual lung hyperinflation in mechanically ventilated patients. Eighteen patients from the intensive care units of two tertiary institutions were included and acted as their own control. Manual lung hyperinflation treatment involved patient positioning (side-lying), suctioning and manual lung hyperinflation. Side-lying treatment involved patient positioning and suctioning alone. Patients received both treatments on the day of data collection. Results demonstrated significant improvement for static respiratory system compliance (P = 0.001) with manual lung hyperinflation treatment compared to side-lying treatment. Manual lung hyperinflation treatment also cleared a significantly greater wet weight of sputum (P = 0.039). There were no differences between manual lung hyperinflation and side-lying treatment for gas exchange (PaO2/FIO2 and PaCO2), mean arterial pressure or heart rate. In conclusion, total static respiratory system compliance and sputum clearance were improved by the addition of manual hyperinflation to a physiotherapy treatment of positioning and suctioning in mechanically ventilated patients without compromise to cardiovascular stability or gas exchange.

Adult↗
PubMed1999

Small intestinal transit, absorption, and permeability in patients with AIDS with and without diarrhoea.

BACKGROUND: Diarrhoea in AIDS is associated with anorexia and weight loss. The importance of gastrointestinal transit in such symptoms has not been addressed. AIMS: To assess jejunal to caecal transit times in subjects with AIDS related diarrhoea and weight loss and correlate these with measures of absorptive capacity and intestinal permeability. METHODS: Jejunal to caecal transit times were assessed in 20 seronegative controls and 60 HIV seropositive subjects from serum analysis of 3-O-methyl-D-glucose and sulphapyridine after ingestion of the monosaccharide and sulphasalazine in aqueous solution. The method also allows an estimation of gastric emptying times for liquids. Intestinal absorptive capacity and permeability were assessed by a combined test using 3-O-methyl-D-glucose, D-xylose, L-rhamnose, and lactulose. RESULTS: Gastric emptying was significantly delayed in all groups of patients with AIDS. Mean jejunal to caecal transit times were not significantly different between controls (246 (62) minutes) and patients without diarrhoea (AIDS, well: 278 (103) minutes; AIDS, wasting: 236 (68) minutes), cytomegalovirus colitis (289 (83) minutes), pathogen negative diarrhoea (192 (100) minutes), or microsporidiosis (190 (113) minutes), although 30% of patients had values below the control range. Patients with cryptosporidiosis differed significantly from controls (135 (35) minutes, p<0.0001), seven of 10 having rapid transit times. Absorptive capacity was reduced and intestinal permeability significantly increased in AIDS, but did not correlate significantly with transit times. CONCLUSION: Small bowel transit is accelerated in many patients with AIDS, particularily in protozoal diarrhoea, but is not the sole explanation for malabsorption of monosaccharides.

AIDS-Related Opportunistic Infections↗
PubMed1998

Last in, first to go: age of acquisition and naming in the elderly.

Twenty-six elderly subjects (ages 71-86) and 10 young adult subjects (ages 22-33) named 206 black-and-white line drawings of objects. Although the two groups did not differ significantly on VIQ, the elderly group named significantly fewer of the objects than the younger group (who were almost at ceiling). A regression analysis of the data from the elderly group found effects of both age of acquisition and name agreement on naming accuracy after 5 and 15 s and an effect of word length after 5 but not 15 s. There were no independent effects of picture complexity, object familiarity, word frequency, or imageability. The majority of the elderly subjects' naming errors were semantic in nature, with circumlocutions, visual errors, and "don't know" responses accounting for most of the remaining errors. The implications of the findings for our understanding of word-finding problems in the elderly are discussed.

Adult↗
PubMed1997

How reliable is peer review? An examination of operating grant proposals simultaneously submitted to two similar peer review systems.

To determine level of agreement and correlation between two similar but separate peer review systems, proposals simultaneously submitted during the same funding year to two agencies using the same scoring system were identified and analyzed (n = 248). There was a direct linear relationship between the scores of the two agencies (r = 0.592, p < 0.001). Raw agreement within whole-digit ranges was moderate (53%) but a Cohen's kappa indicated that agreement beyond chance was only fair (kappa = 0.29, 95% CI = 0.198, 0.382). When proposals were arbitrarily categorized as being "clearly fundable" (on a 0-5 scale, score > or = 3.0) or "not clearly fundable" (score < 3.0), raw agreement was 73% and agreement beyond chance was moderate (kappa = 0.444, 95% CI = 0.382, 0.552). In cases where there was inter-agency disagreement on the fundability of the project, the difference in scores was greater than in those in which there was agreement. In a subsample of 128 pairs, variables describing the application and the applicant (i.e., principal investigator) were coded, but none explained inter-agency agreement on the "fundability" of proposals.

Humans↗
PubMed1997

Family anxiety in advanced cancer: a multicentre prospective study in Ireland.

Six home care services in Southern Ireland collected data on a total of 757 patients over a 6-month period. Patient and family well-being were measured using the staff-rated Support Team Assessment Schedule and Karnofsky Index. Five hundred and eight patients died while in care, 75% of whom died at home. At referral, 32% of families were rated as having severe or overwhelming anxiety. During the last week of care, anxiety remained severe for 26% of family members. Patient and family well-being were inter-related, and there were significant interactions between family anxiety and patient physical and psychological symptoms, and communication. Discriminant analysis produced two predictive models. In model 1, family anxiety at referral strongly predicts family anxiety in the last week of life. In model 2, family anxiety at referral is excluded from the analysis, and the significant predictor factors at referral for family anxiety in the last 4 weeks of life are patient symptom control, sex of patient, diagnosis and patient age.

Adolescent↗
PubMed1997

Self-reported cardiovascular disease and risk factors. Prevalence in Ontario among women 50 and older.

OBJECTIVE: To determine the prevalence of self-reported cardiovascular disease and risk factors among Ontario women aged 50 and older. DESIGN: Analysis of the 1990 Ontario Health Survey, a population-based, cross-sectional survey. SETTING: Ontario communities. PARTICIPANTS: Residents of Ontario communities during 1990 who responded to the 1990 Ontario Health Survey (61,239 respondents in 35,479 households), weighted to represent the population of Ontario. MAIN OUTCOME MEASURES: Reported heart disease, hypertension, diabetes, height and weight, physical activity, and smoking habits. RESULTS: Nearly 11% of women aged 50 and older report "heart disease"; 24.9% hypertension, and 5.4% diabetes. Women were less likely than men to smoke daily, to smoke 25 or more cigarettes a day, and to be overweight, but were more likely to have lower levels of physical activity. CONCLUSIONS: The prevalence of self-reported heart disease and medical and lifestyle risk factors for heart disease is relatively high among Ontario women aged 50 and older. Physicians and public health officials must keep women in mind when designing or implementing programs or services for heart disease.

Cardiovascular Diseases↗
PubMed1995

Evaluation of cardiovascular grant-in-aid applications by peer review: influence of internal and external reviewers and committees.

OBJECTIVE: To determine what factors of the peer review process played a significant role in the assignment of scores for scientific merit by a major cardiovascular research finding agency. Specific variables studied included scores of internal and external reviewers, committee assignment and year of application. DESIGN AND SETTING: Retrospective analysis of research proposals submitted to the Heart and Stroke Foundation of Ontario from 1990 to 1994. SUBJECTS: Of a total database of 804 grant-in-aid (operating or project) proposals submitted to the Heart and Stroke Foundation of Ontario from 1990 to 1994, 779 had complete data and were included in the study. Variables analyzed were scores of internal and external reviewers, final committee score, committee assignment and year of application. MAIN RESULTS: There was poor correlation (r = 0.113) between external reviewers of grant proposals and only slightly better correlation between internal reviewers (r = 0.331). When mean internal and external scores were analyzed, correlation improved (r = 0.451) but agreement beyond chance was only moderate (weighed Cohen's kappa = 0.532). Regression analysis established that mean internal score had a greater impact on final committee score (r2 = 0.607, P < 0.001) than mean internal score (r2 = 0.348, P < 0.001). When review committee was entered as a dummy variable into a regression statement, it was statistically significant (P < 0.001) but explained less than 8% of variance in the final committee score. Mean scores showed a small 'upward creep' over the five-year period but explained less than 4% of variance in final committee score (r2 = 0.039, P < 0.001). CONCLUSIONS: In the peer review system studied, the scores of internal reviewers were more closely correlated to final committee score for scientific merit than those of external reviewers. Nevertheless, final committee scores were significantly different from either internal or external scores, suggesting that the process of committee discussion is an important, and highly influential, step in the peer review process.

Canada↗