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Biomedical subjects

K Sharpe

Publications and source records attributed to K Sharpe.

At least 19 recordsLinked to original sources
PubMed2006

Effects of Hemopure on maximal oxygen uptake and endurance performance in healthy humans.

Haemoglobin-based oxygen carriers (HBOCs) such as Hemopure are touted as a tenable substitute for red blood cells and therefore potential doping agents, although the mechanisms of oxygen transport of HBOCs are incompletely understood. We investigated whether infusion of Hemopure increased maximal oxygen uptake (V.O 2max) and endurance performance in healthy subjects. Twelve male subjects performed two 4-minute submaximal exercise bouts equivalent to 60 % and 75 % of V.O (2max) on a cycle ergometer, followed by a ramped incremental protocol to elicit V.O (2max). A crossover design tested the effect of infusing either 30 g (6 subjects) or 45 g (6 subjects) of Hemopure versus a placebo. Under our study conditions, Hemopure did not increase V.O (2max) nor endurance performance. However, the infusion of Hemopure caused a decrease in heart rate of approximately 10 bpm (p=0.009) and an average increase in mean ( approximately 7 mmHg) and diastolic blood pressure ( approximately 8 mmHg) (p=0.046) at submaximal and maximal exercise intensities. Infusion of Hemopure did not bestow the same physiological advantages generally associated with infusion of red blood cells. It is conceivable that under exercise conditions, the hypertensive effects of Hemopure counter the performance-enhancing effect of improved blood oxygen carrying capacity.

Blood Pressure↗
PubMed2006

Acute weight loss followed by an aggressive nutritional recovery strategy has little impact on on-water rowing performance.

OBJECTIVES: To assess the influence of moderate, acute weight loss on on-water rowing performance when aggressive nutritional recovery strategies were used in the two hours between weigh in and racing. METHODS: Competitive rowers (n = 17) undertook three on-water 1800 m time trials under cool conditions (mean (SD) temperature 8.4 (2.0) degrees C), each separated by 48 hours. No weight limit was imposed for the first time trial--that is, unrestricted body mass (UNR1). However, one of the remaining two trials followed a 4% loss in body mass in the previous 24 hours (WT(-4%)). No weight limit was imposed for the other trial (UNR2). Aggressive nutritional recovery strategies (WT(-4%), 2.3 g/kg carbohydrate, 34 mg/kg Na+, and 28.4 ml/kg fluid; UNR, ad libitum) were used in the first 90 minutes of the two hours between weigh in and performance trials. RESULTS: WT(-4%) had only a small and statistically non-significant effect on the on-water time trial performance (mean 1.0 second, 95% confidence interval (CI) -0.9 to 2.8; p = 0.29) compared with UNR. This was despite a significant decrease in plasma volume at the time of weigh in for WT(-4%) compared with UNR (-9.2%, 95% CI -12.8% to -5.6%; p<0.001). CONCLUSIONS: Acute weight loss of up to 4% over 24 hours, when combined with aggressive nutritional recovery strategies, can be undertaken with minimal impact on on-water rowing performance, at least in cool conditions.

Adolescent↗
PubMed2005

Physique traits of lightweight rowers and their relationship to competitive success.

OBJECTIVES: Physique traits and their relationship to competitive success were assessed amongst lightweight rowers competing at the 2003 Australian Rowing Championships. METHODS: Full anthropometric profiles were collected from 107 lightweight rowers (n = 65 males, n = 45 females) competing in the Under 23 and Open age categories. Performance assessments were obtained for 66 of these rowers based on results in the single sculls events. The relationship between physique traits and competitive success was then determined. RESULTS: Lower body fat (heat time estimate -8.4 s kg(-1), p<0.01), greater total body mass (heat time estimate -4.4 s kg(-1), p = 0.03), and muscle mass (heat time estimate -10.2 s kg(-1), p<0.01) were associated with faster 2000 m heat times. CONCLUSIONS: The more successful lightweight rowers were those who had lower body fat and greater total muscle mass.

Adult↗
PubMed2001

Detection of recombinant human erythropoietin abuse in athletes utilizing markers of altered erythropoiesis.

BACKGROUND AND OBJECTIVES: The detection of recombinant human erythropoietin (r-HuEPO) abuse by athletes remains problematic. The main aim of this study was to demonstrate that the five indirect markers of altered erythropoiesis identified in our earlier work were reliable evidence of current or recently discontinued r-HuEPO use. A subsidiary aim was to refine weightings of the five markers in the initial model using a much larger data set than in the pilot study. A final aim was to verify that the hematologic response to r-HuEPO did not differ between Caucasian and Asiatic subjects. DESIGN AND METHODS: Recreational athletes resident in Sydney, Australia (Sydney, n = 49; 16 women, 33 men) or Beijing, China (Beijing, n=24; 12 women, 12 men) were randomly assigned to r-HuEPO or placebo groups prior to a 25 day administration phase. Injections of r-HuEPO (or saline) were administered double-blind at a dose of 50 IU/kg three times per week, with oral iron (105 mg) or placebo supplements taken daily by all subjects. Blood profiles were monitored during and for 4 weeks after drug administration for hematocrit (Hct), reticulocyte hematocrit (RetHct), percent macrocytes (%Macro), serum erythropoietin (EPO) and soluble transferrin receptor (sTfr), since we had previously shown that these five variables were indicative of r-HuEPO use. RESULTS: The changes in Hct, RetHct, %Macro, EPO and sTfr in the Sydney trial were qualitatively very similar to the changes noted in our previous administration trial involving recreational athletes of similar genetic origin. Statistical models developed from Fisher's discriminant analysis were able to categorize the user and placebo groups correctly. The same hematologic response was demonstrated in Beijing athletes also administered r-HuEPO. INTERPRETATION AND CONCLUSIONS: This paper confirms that r-HuEPO administration causes a predictable and reproducible hematologic response. These markers are disturbed both during and for several weeks following r-HuEPO administration. This work establishes an indirect blood test which offers a useful means of detecting and deterring r-HuEPO abuse. Ethnicity did not influence the markers identified as being able to detect athletes who abuse r-HuEPO.

Adult↗
PubMed1997

Effect of cereal fibre source and processing on rectal epithelial cell proliferation.

BACKGROUND: Low fat and wheat bran interventions significantly reduced the growth of small to large adenomas and modestly suppressed rectal epithelial cell proliferation in the Australian Polyp Prevention Project. AIM: To study the effect of unprocessed wheat bran, unprocessed oat bran and processed wheat bran (Kellogg's All Bran) on rectal epithelial cell proliferation. PATIENTS: Twenty subjects with recent adenomas and a high fat background diet were recruited. METHODS: Rectal biopsy specimens were taken at entry and at the end of three six-week periods of oat bran (64 g/day), wheat bran (25 g/day) and All Bran (38 g/day), all in association with a diet < 25% energy as fat, in a randomised cross-over trial. Each of the bran supplements had a total of 11 g dietary fibre. The biopsy specimens were fixed in methacarn and stained immunohistochemically for presence of the proliferating cell nuclear antigen (PCNA). The kinetics used to measure proliferation were labelling index, whole distribution of labelled cells, and labelled cells in the top two-fifths of crypts using analysis of variance. RESULTS: There were no significant differences in mean labelling indexes between the four diets or in the percentage of labelled cells in the top two-fifths (p = 0.59), but activity in the top two-fifths of crypts was lowest with wheat bran. The mean (SD) labelling indexes were 2.23 (0.11)% for control, 2.13 (0.08)% for wheat bran, 2.19 (0.09)% for oat bran, and 2.12 (0.08)% for All Bran. The proportion in the top two-fifths of the crypts was 2.6 (0.6)% for control, 2.15 (0.5)% for wheat bran, 3.3 (0.9)% for oat bran, and 3.1 (0.9)% for All Bran. On analysis of whole distribution, there was no significant overall effect of diets but there was a difference between subjects. Analysis including total fibre intake also did not identify effects on proliferation. CONCLUSION: In this study of high risk subjects with initial high fat diets, dietary fibre in association with a low fat diet had no effect on rectal epithelial cell proliferation, although wheat bran had the greatest effect on percentage of labelled cells in the top two-fifths of crypts.

Adenoma↗
PubMed1997

A Longitudinal Study of Lung Function in Non-asthmatic Workers in an Aluminum Smelter.

This paper reports a longitudinal study carried out between 1977 and 1989 to determine whether the long-term rate of change in the forced expiratory volume in 1 second (FEV&inf1;) is influenced by exposure to the potroom environment of an aluminum smelter. Workers with diagnosed asthma were excluded from the analysis. The study population consisted of 393 potroom workers, with rate of change in FEV&inf1; used to assess any impairment in airway function. Post-shift urinary fluoride levels and length of service were used to measure exposure. After allowing for age, smoking behavior, and a standardized measure of FEV&inf1;, the rate of change in FEV&inf1; was found to be significantly greater for those workers who had worked shorter times in the potroom. Possible explanations for this finding include unrecognized asthma, a healthy-worker effect, and an exposure effect that occurs early in a worker's experience in the potroom; these explanations are not necessarily mutually exclusive. Apart from the risk of occupational asthma, there does not appear to be any long-term effect on the rate of decline in FEV&inf1; associated with exposure to the potroom environment in workers who remain at work longer than 40 months.

Journal Article↗
PubMed1997

The effect of incubation of rectal biopsies on measures of proliferation using proliferating cell nuclear antigen in comparison with 5-bromo-2-deoxyuridine.

Rectal epithelial cell kinetics are used as intermediate markers for colorectal cancer and relate to risk. In this study, measures of proliferation using direct immunohistochemistry for proliferating cell nuclear antigen (PCNA) were compared to in vitro labeling by bromodeoxyuridine (BrdUrd) and incubated biopsies that were later stained for PCNA (PCNA-I) in human rectal biopsies. The study group consisted of 20 sets of biopsies from 12 subjects participating in an intervention trial. Fresh nonincubated biopsies were fixed in methacarn and stained immunohistochemically for PCNA (clone 19A2). In parallel biopsies, BrdUrd was incorporated into the DNA of S-phase cells during a 2-h incubation at 37 degrees C under hyperbaric conditions and localized by immunohistochemistry. Additionally, biopsies were incubated under hyperbaric conditions for 2 h at 37 degrees C, fixed in methacarn, and stained for PCNA (PCNA-I). There was a highly significant difference in the labeling index between the three methods (P < 0.01), but there was no significant difference between subjects (P = 0.439). The mean labeling index was 2.3 +/- 0.1% for PCNA, 2.9 +/- 0.1% for PCNA-I, and 4.1 +/- 0.1% for BrdUrd. The proportion of labeled cells in the top two-fifths was significantly higher (P = 0.01) for BrdUrd (5.5 +/- 0.8%) and PCNA-I (6.4 +/- 1.1%) compared to PCNA (3.1 +/- 0.6%), and a significant difference was seen between subjects (P = 0.038). PCNA-I and BrdUrd methods had similar crypt heights with 73.5 +/- 1.8 and 71.2 +/- 1.3 cells/crypt column, respectively, but were significantly shorter (P < 0.001) than PCNA with 83.4 +/- 1.5 cells/crypt column, indicating a loss of cells during organ culture. The simplicity of the PCNA technique, which avoids potential perturbations occurring during organ culture, has considerable appeal as a marker for colorectal cancer risk, but additional studies are needed to correlate PCNA with neoplastic risk.

Adult↗
PubMed1996

Effect of VDUs on the eyes: report of a 6-year epidemiological study.

One thousand, three hundred and sixteen office workers [692 visual display unit (VDU) users, 624 controls in the first year] were examined once each year over a 6-year period to establish whether or not VDU work was a factor in the occurrence of visual symptoms, ocular abnormalities, or ocular disease. Statistical analysis showed that although there were differences between VDU users and nonusers in the amount of myopia, the prevalence of some symptoms, and the prevalence of signs of fundal or vitreal disease, the differences were small and there were no clear trends or patterns to lend convincing support to the hypothesis that VDU work may be a risk factor. There were no significant differences in the prevalence and incidence of cataract.

Adult↗
PubMed1994

Preoperative risk evaluation for lung cancer resection: predicted postoperative product as a predictor of surgical mortality.

We assessed the capacity to predict surgical mortality, complications, and functional loss by using the results of resting and exercise respiratory function. Measurements were made before and 4 mo after lung resection in 54 consecutive patients with bronchogenic carcinoma. Predicted postoperative (ppo) FEV1 and DLCO were derived using quantitative lung perfusion scans when baseline FEV1 was < 55% predicted, and by proportional loss of pulmonary segments (total = 19 segments) when FEV1 was > 55% predicted. The patients were aged 67 +/- 7 (mean +/- SD) yr, with an FEV1 of 76 +/- 23% predicted, FEV1/FVC of 55 +/- 13%. and DLCO of 85 +/- 22% predicted. Eleven of the patients had pneumonectomy, 29 had lobectomy, 12 had wedge resection, and two had no resection. Wilcoxon and stepwise logistic regression analyses were used to determine which indices best predicted outcome. Postoperative values were correlated (r = 0.87, p < 0.0001) with actual 4/12 postoperative values of FEV1% and of DLCO (r = 0.56, p < 0.0001). The best predictors (all p < 0.05) for each outcome, in order of usefulness, were as follows. For surgical mortality: (1) the predicted postoperative product (PPP) of ppo FEV1% x ppo DLCO%; (2) ppo DLCO%; (3) ppo FEV1%, and (4) RV, FRC, and SaO2 on the maximal step exercise test. For respiratory complications: body mass index (BMI) (for patients undergoing lobectomy or wedge resection only). For cardiac complications: (1) age; (2) SaO2 at baseline and on the maximal step exercise test; (3) PaO2; (4) PaCO2; and (5) minute ventilation at maximal exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Rectal epithelial cell proliferation: comparison of errors of measurement with inter-subject variance. Australian Polyp Prevention Project Investigators.

If measures of rectal epithelial kinetics are to be used on a large scale, or as part of multicenter studies, the variance of repeated measures must be sufficiently small to detect the effect of clinical status and dietary, or chemoprevention interventions. Errors in measurement can be categorized as intra-reader (sigma 2I), inter-biopsy (sigma 2B), inter-laboratory (sigma 2L), and inter-reader (sigma 2R); the sum of these (sigma 2T) when compared to inter-subject variance (sigma 2S) is a measure of the precision with which cell kinetics can be estimated for a given subject. We estimated the variances of the component errors in four separate experiments, each involving 6 to 10 subjects, using the proliferating cell nuclear antigen (PCNA) technique. PCNA labeling index variances for a single laboratory study were sigma 2I = 0.02-0.07 and sigma 2B = 0.08-0.15. Inter-laboratory and inter-reader variances were sigma 2L = 0.08 and sigma 2R = 0.03. Summing the errors applicable within a laboratory gives a rounded estimate of 0.15. For inter-laboratory studies the total error (sigma 2T) is greater, estimated in our two-laboratory study as 0.3. In a separate study, the variation between biopsies (sigma 2B) could be accounted for by the variation between crypts within biopsies; an acceptable level of accuracy is achieved after counting 20-30 crypts. In contrast to the measurement errors, the variance between subjects, which includes a treatment effect of diet, was larger, estimated to be between 0.75 and 1.30.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1991

Caffeine restriction: effect on mild hypertension.

OBJECTIVE: To determine the effects on blood pressure of modifying dietary caffeine intake in patients with mild and borderline hypertension by monitoring ambulatory and clinic blood pressure. DESIGN: Four way, randomised, crossover trial of four consecutive two week dietary regimens: normal diet, caffeine free diet alone, caffeine free diet with decaffeinated instant coffee, caffeine free diet with caffeinated instant coffee (instant coffee phases conducted double blind). SETTING: Hospital hypertension clinic, Scotland. PATIENTS: 52 patients (23 men; aged 26-67 years) with untreated borderline or mild hypertension (diastolic blood pressure 90-105 mm Hg) who normally drank a minimum of three cups of coffee daily. MAIN OUTCOME MEASURES: Mean ambulatory blood pressure over 24 hours; mean morning, daytime, and night time ambulatory blood pressure; sitting clinic blood pressure at 1700; plasma caffeine concentration at 1700 on the last day of each regimen. RESULTS: Mean 24 hour ambulatory blood pressure was not different between regimens. There was no difference in blood pressure variability between regimens. During the caffeine free diet alone morning ambulatory diastolic blood pressure was higher (2.8 mm Hg) than during the caffeine free diet with caffeinated coffee. Mean sitting clinic systolic blood pressure was higher at 1700 (4.7 mm Hg) with a caffeine free diet than with the caffeine free diet with caffeinated coffee (p less than 0.05). Dietary compliance as assessed by plasma caffeine concentration was excellent. There was no significant correlation between plasma caffeine concentration and blood pressure. CONCLUSIONS: Drinking caffeinated instant coffee over a two week period does not adversely influence blood pressure in patients with borderline or mild hypertension; abstinence is of no benefit.

Adult↗
PubMed1991

Estimating premorbid intellectual level in dementia using the National Adult Reading Test: a Canadian study.

Twenty elderly demented subjects were compared with 20 elderly controls using a neuropsychological test battery which included the National Adult Reading Test (NART) and the WAIS-R. Significant differences emerged between the two groups on all of the cognitive measures administered, with the exception of the NART and the Verbal-Performance IQ discrepancy. Models were constructed using the normal controls as subjects where NART errors and WAIS-R Vocabulary age scaled scores were regressed against WAIS-R FSIQ and WAIS-R VIQ. These regression equations were then used to estimate premorbid intelligence levels in the demented sample, and these estimates were compared with the 'current' measures (WAIS-R FSIQ and WAIS-R VIQ). NART estimated IQs were significantly higher than Vocabulary estimated IQs, which in turn were significantly higher than WAIS-R FSIQ and WAIS-R VIQ. These results confirm that the ability to pronounce irregular words correctly remains relatively unimpaired in dementia.

Aged↗
PubMed1986

Factors affecting compliance in colorectal cancer screening. Results of a study performed in Ballarat.

Non-compliance in screening programmes for colorectal cancer is likely to be the most important factor limiting the impact of screening on mortality. This study aimed to determine risk factors and correlates of compliance that could be readily identified by general practitioners. A total of 581 eligible subjects aged 40 to 75 years completed a questionnaire that covered demographic factors, personal medical history, family history of colorectal cancer and smoking status. Faecal occult blood tests were then offered by the general practitioner and compliance correlated with responses. The over-all compliance was 44% and increased to 51% for those who accepted the self-testing kit at consultation. For men, compliance increased with increasing level of education and was significantly greater for non-smokers than for smokers. For women, compliance increased with increasing age, and was greater for those with either symptoms and/or a family history of colorectal cancer. A doctor group-practice factor appeared to influence acceptance versus refusal of the test kit from the doctor. A triage approach to screening in general practice may improve over-all compliance and the yield of tumours. With this strategy, patients at high risk (for example, those with a family history of colorectal cancer or in older age groups) are identified first. Particular attention should be given during consultation to those at high risk who have poor compliance profiles (for example male smokers with a family history of colorectal cancer). High-risk subjects with high compliance profiles would need less attention and low-risk individuals would need least attention.

Adult↗
PubMed1983

A comparative study of surgical skin preparation methods.

Analysis of a randomized study of preoperative skin preparation techniques in thoracic and general surgical patients revealed that the use of a one minute alcohol cleansing and application of an antimicrobial film provides equivalent bactericidal activity to a five minute iodophor scrub and paint. Initial bacterial kill is greater with a one minute alcohol cleansing than a five minute iodophor scrub. There were fewer patients with high bacterial counts at the time of closure in the groups treated with the antimicrobial film than in the traditional iodophor scrub group. Saving in preoperative operating room time can be achieved using a one minute alcohol cleansing plus application of an antimicrobial film with equal antibacterial efficacy to that of conventional methods.

Bacteria↗
PubMed1980

Some clinical effects of oestrogen-progestogen therapy in surgically castrated women.

This study reports some of the effects of oestrogen and progestogen therapy. forty-nine women who had undergone hysterectomy and bilateral salpingo-oophorectomy took part in a double blind crossover study during which they received ethinyl oestradiol 50 micrograms/day, norgestrel 250 micrograms/day, the combination of these substances "Nordiol" and placebo. Somatic complaints were assessed at monthly interviews and weight and blood pressure recorded. The addition of norgestrel to ethinyl oestradiol therapy resulted in less dryness of skin but significantly increased mastalgia and breast size. There were no significant differences between drugs on amount of facial hair, acne, arthralgia, pruritus vulvae, vaginal discharge, vaginal odour, dyspareunia, weight or blood pressure. There was a significant reduction of diastolic blood pressure with the time duration of the study.

Blood Pressure↗
PubMed1979

Hormone therapy and affect.

This study investigated the influence of hormone therapy on affect in a double blind crossover trail. The sample consisted of 49 women who had previously undergone hysterectomy and bilateral oophorectomy. Therapy consisted of 3 mth each of ethynyl oestradiol-50 micron/day, levonorgestrel-250 micron/day, "Nordial"-a combination of these two substances, and placebo. Affect was measured by the Hamilton Depression Rating Scale, verbal reports by women and self-ratings on visual analogue scales. Ethinyl oestradiol was found to have a beneficial influence on aspects of affect such as Hamilton scores, anxiety irritability and insomnia. The influence of hormones on Hamilton scores could be partly but not fully explained by the alleviation of hot flushes. Norgestrel showed less favourable changes initially but these tended to diminish by the third therapy month. Most of the women studied were not clinically depressed. Anxiety symptoms were the major features exhibited in the group of women investigated. The results of this study suggest that visual analogue rating scales are of questionable validity in assessing affect in patients without any appreciable psychiatric morbidity.

Affect↗