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Biomedical subjects

G Schofield

Publications and source records attributed to G Schofield.

17 recordsLinked to original sources
PubMed2006

Pedometer steps in primary school-aged children: a comparison of school-based and out-of-school activity.

While studies of the physical activity habits of New Zealand children have been carried out, the findings have been restricted by the use of proxy and self-report measures and limited to total overall daily activity. Objective measurement of children's in-school and out-of school physical activity using pedometry is likely to provide more accurate data on habitual daily activity. To date, no such data are available for New Zealand children. In the present study, children from school years 1-6 (girls, n=46; boys, n=45) at a New Zealand primary school wore a Yamax Digiwalker SW-200 pedometer to record school-based and out-of-school steps over a 3-day period. Mean daily steps for the overall sample were 14 333 (S.D.=4110). Boys (X=15 606; S.D.=4601) were significantly more active than girls (X=13 031; S.D.=3079) (p=.00). Mean steps were also significantly higher in older age groups for both boys (p=.03) and in particular, girls (p=.00). Of note, for the overall sample, steps taken out of school made up 52.4% of total daily steps. Girls (53.6%) and boys (51.3%) took a similar proportion of their overall daily steps outside of the school environment. While a significant difference was found between the most and least active tertiles in steps taken during both during school hours (p=.00) and outside of school hours (p=.00), the most active third of the sample completed significantly more of their daily steps outside of school (55.1%) than did their least active (46.7%) counterparts (p=.00). These results suggest that physical activity outside of the school environment is a key contributor to a child's overall level of physical activity, reinforcing the need for interventions targeting the family and community as well as the school environment.

Age Factors↗
PubMed2006

Video capsule endoscopy in peutz-jeghers syndrome: a blinded comparison with barium follow-through for detection of small-bowel polyps.

BACKGROUND AND STUDY AIMS: Video capsule endoscopy has shown promise for the surveillance of significant small-bowel polyps in patients with Peutz-Jeghers syndrome. In this study the yield of significant small-bowel polyps by capsule endoscopy was compared to the yield of these polyps by barium follow-through in adults with Peutz-Jeghers syndrome. PATIENTS AND METHODS: A total of 19 adults with Peutz-Jeghers syndrome who were undergoing surveillance underwent both capsule endoscopy and barium follow-through examinations, and the number of small-bowel polyps of at least 1 cm in diameter that were detected was recorded for each method. The two methods were assessed in terms of comfort and convenience for the patients and their preferred future surveillance method, using a questionnaire. RESULTS: Capsule endoscopy detected a median of four significant small-bowel polyps while barium follow-through detected a median of one (P = 0.008). There was a trend towards more participants having at least one significant small-bowel polyp detected by capsule endoscopy than was the case with barium follow-through, though capsule endoscopy seemed to be less reliable for accurate sizing of polyps that were at the limit of clinical significance. Most participants expressed a preference for capsule endoscopy for future surveillance. CONCLUSIONS: Capsule endoscopy should replace barium follow-through for the surveillance of small-bowel polyps in adults with Peutz-Jeghers syndrome, but the findings of this study should be interpreted with caution until a more reliable means of sizing polyps by capsule endoscopy is available.

Administration, Oral↗
PubMed2005

Objectively-measured physical activity in New Zealand workers.

To date, no objective measurements of New Zealanders' physical activity have been reported. The relative contribution of work time activity to total daily physical activity by gender and occupational category has also not been measured objectively in any population. The present study reports such data using pedometer steps counts to quantify both work and non-work physical activity in a sample of New Zealand adult workers in six different occupational categories over a three-day period. Females (9943+/-3855 steps) had slightly higher, but not significantly different (F=0.084(1,179)1, p=0.772) daily step counts than males (9766+/-3965 steps). Using the 10 000 steps a day criterion, 57% of the sample were considered at least low-active. Analysis of variance was used to identify between group (occupational) differences in workplace physical activity (F=11.189(5,175), p<0.001), non-work physical activity (F=2.596(5.175), p=0.027), and total physical activity (F=6.265(5,175), p<0.001). Tukey post hoc comparisons showed significant differences with retail and blue collar workers achieving higher activity levels in comparison to the other occupational categories in work and total physical activity. Odds ratios were calculated to find the odds of being in the top half of activity classification for work and non-work physical activity by tertile splits of work time, active transportation use, sport and exercise participation, television and computer viewing, and passive recreation. Active transportation and passive recreation were related to increased odds of higher work pedometer steps. For non-work pedometer values, television and computer use increased the likelihood of being in the lowest activity group, while sport and exercise participation were associated with increased activity levels.

Adult↗
PubMed2005

Development of a psychometrically valid and reliable sports nutrition knowledge questionnaire.

The present range of sports nutrition knowledge questionnaires have inadequate psychometric validation, and few are up to date in a rapidly changing discipline. The purpose of this study was to design a sports nutrition questionnaire that satisfied acceptable psychometric criteria of validity (content and construct) and reliability (test-retest). The questionnaire was designed by an expert panel of six sports dietitians and distributed to five groups, selected for their expected variation in sports nutrition knowledge. Dietitians, university business staff and nutrition students received questionnaires via e-mail. The response rates obtained were 21.3% (n = 49), 34.4% (n = 33), and 72.0% (n = 18), respectively. University business and fitness students completed questionnaires during class time. Response rates were 52.3% (n = 23) and 75.4% (n = 49), respectively. The questionnaire was administered a second time to the business staff and the dietitians to assess test-retest reliability. Two methods were used: 1, Pearson's product-moment correlation; and 2, a percentage calculation of questions answered in an identical manner on both test occasions. Reliability was acceptable with Method 1 yielding acceptable values (r = 0.74-0.93), aside from the fluid sub-category (r = 0.52). Method 2 showed good test-retest concordance with 81.2% duplication of responses of all questions. Construct validity was high, as indicated by significant mean knowledge score differences between the groups (p = 0.0001). Dietitians and nutrition students achieved significantly greater mean scores than the remaining groups. The findings of this study indicate that the questionnaire is suitably valid and reliable to be used in research and practice to determine sports nutrition knowledge.

Dietetics↗
PubMed2004

Pancolonic indigo carmine dye spraying for the detection of dysplasia in ulcerative colitis.

BACKGROUND AND AIMS: Colonoscopic surveillance for cancer in longstanding extensive ulcerative colitis relies heavily on non-targeted mucosal biopsies. Chromoendoscopy can aid detection of subtle mucosal abnormalities. We hypothesised that routine pancolonic indigo carmine dye spraying would improve the macroscopic detection of dysplasia and reduce the dependence on non-targeted biopsies. PATIENTS AND METHODS: One hundred patients with longstanding extensive ulcerative colitis attending for colonoscopic surveillance underwent "back to back" colonoscopies. During the first examination, visible abnormalities were biopsied, and quadrantic non-targeted biopsies were taken every 10 cm. Pancolonic indigo carmine (0.1%) was used during the second colonoscopic examination, and any additional visible abnormalities were biopsied. RESULTS: Median extubation times for the first and second colonoscopies were 11 and 10 minutes, respectively. The non-targeted biopsy protocol detected no dysplasia in 2904 biopsies. Forty three mucosal abnormalities (20 patients) were detected during the pre-dye spray colonoscopy of which two (two patients) were dysplastic: both were considered to be dysplasia associated lesions/masses. A total of 114 additional abnormalities (55 patients) were detected following dye spraying, of which seven (five patients) were dysplastic: all were considered to be adenomas. There was a strong trend towards statistically increased dysplasia detection following dye spraying (p = 0.06, paired exact test). The targeted biopsy protocol detected dysplasia in significantly more patients than the non-targeted protocol (p = 0.02, paired exact test). CONCLUSIONS: No dysplasia was detected in 2904 non-targeted biopsies. In comparison, a targeted biopsy protocol with pancolonic chromoendoscopy required fewer biopsies (157) yet detected nine dysplastic lesions, seven of which were only visible after indigo carmine application. Careful mucosal examination aided by pancolonic chromoendoscopy and targeted biopsies of suspicious lesions may be a more effective surveillance methodology than taking multiple non-targeted biopsies.

Adult↗
PubMed2004

Cancer surveillance in longstanding ulcerative colitis: endoscopic appearances help predict cancer risk.

BACKGROUND AND AIMS: The risk of colorectal cancer is increased in ulcerative colitis (UC). Patients with UC have diverse colonoscopic appearances. Determining colonoscopic markers for cancer risk could allow patient risk stratification. PATIENTS AND METHODS: Following on from an earlier study which demonstrated a correlation between inflammation severity and neoplasia risk, a case control study was performed to look for colonoscopic markers of colorectal neoplasia risk in UC. Each patient with neoplasia detected between 1988 and 2002 was matched with two non-dysplastic colitic controls. Data were collected on post-inflammatory polyps, scarring, strictures, backwash ileitis, a shortened, tubular, or featureless colon, severe inflammation, and normal looking surveillance colonoscopies. RESULTS: Cases (n = 68) and controls (n = 136) were well matched. On univariate analysis, cases were significantly more likely to have post-inflammatory polyps (odds ratio (OR) 2.14 (95% confidence interval 1.24-3.70)), strictures (OR 4.22; 1.08-15.54), shortened colons (OR 10.0; 1.17-85.6), tubular colons (OR 2.03; 1.00-4.08), or segments of severe inflammation (OR 3.38; 1.41-10.13), and less likely to have had a macroscopically normal looking colonoscopy (OR 0.40; 0.21-0.74). After multivariate analysis, a macroscopically normal looking colonoscopy (OR 0.38; 0.19-0.73), post-inflammatory polyps (2.29; 1.28-4.11), and strictures (4.62; 1.03-20.8) remained significant. The five year risk of colorectal cancer following a normal looking colonoscopy was no different from that of matched general population controls. CONCLUSIONS: Macroscopic colonoscopic features help predict neoplasia risk in UC. Features of previous/ongoing inflammation signify an increased risk. A macroscopically normal looking colonoscopy returns the cancer risk to that of the general population: it should be possible to reduce surveillance frequency to five years in this cohort.

Adolescent↗
PubMed2002

The epidemiology of medically attended sport and recreational injuries in Queensland.

The Queensland Sport and Recreation Injury Survey (QSRIS) is a retrospective study describing the annual incidence of injuries in the state of Queensland, Australia, resulting from sport and recreational activity involvement. Data were collected by means of a computer-assisted-telephone-interview (CATI) survey of a representative sample of Queenslanders in the spring of 2000. The sample produced a total of 1337 respondents aged 18 to 94 years. The survey asked information regarding medically attended, non-fatal injuries resulting from sport and recreational activities in the past 12 months. Of the 1337 individuals surveyed, 191 of the respondents reported one or more injuries that required medical attention resulting in a total of 222 Injuries. This represents an overall rate of 1,666 medically attended injuries per 10,000 people. Among those reporting a sport or recreational injury, the most common types of injuries were a strained/pulled muscle (30.9%), sprained/torn ligament (24.1%), and fracture (12.6%). The most common bodily locations of injuries were the shoulders (13.0%) and knees (12.5%). Results detail the nature and type of injury, medical professional attending to the injury and the nature of the sport or recreational activity that led to the reported injury, highlighting the number of injuries associated with general fitness activities achieved through high participation rates and low injury rates. This remains an area of much needed attention given the promotional push towards raising the levels of physical activity at a population level.

Adolescent↗
PubMed2000

C2-Ceramide increases cytoplasmic calcium concentrations in human parathyroid cells.

Effects of extracellular calcium ([Ca(2+)](ext)) on parathyroid cells are mainly due to the activation of a plasma membrane calcium receptor (CaR) coupled with release of intracellular calcium. In addition, high [Ca(2+)](ext) activates the sphingomyelin pathway in bovine parathyroid cells, generating ceramides and sphingosine. This study explored the direct effects of synthetic ceramides on [Ca(2+)](i) in human parathyroid cells. Cells from five parathyroid adenomas removed from patients with primary hyperparathyroidism were dispersed and maintained in primary culture. Intracellular calcium concentration ([Ca(2+)](i)) [Ca(2+)](i) was monitored using standard quantitative fluorescence microscopy in Fura-2/AM-loaded cells. Laser scanning microscopy was used to monitor the intracellular distribution of a fluorescent ceramide analogue (BODIPY-C5). After addition of 10 microM C2-ceramide (N-acetyl-d-erythro-sphingosine), [Ca(2+)](i) increased rapidly (30-60 s) to a peak three times above basal levels in 70% of cells (37/55 cells in four experiments). This effect appeared to be due to release of Ca(2+) from intracellular stores rather than Ca(2+) entry from the extracellular medium. C2-responsive cells had a smaller [Ca(2+)](i) response to subsequent stimulation with the CaR agonist-neomycin (1 mM). These responses were specific to C2 since C6-ceramide (N-hexanoyl-d-erythro-sphingosine) did not affect basal [Ca(2+)](i) nor the responses to an increase in [Ca(2+)](ext) and to neomycin. C5-BODIPY generated intense perinuclear fluorescence, suggesting targeting of the ceramides to the Golgi apparatus. These data demonstrate that endogenous generation of ceramides has the potential to modulate changes in [Ca(2+)](i) and secretion in response to [Ca(2+)](ext) in human parathyroid cells.

Calcium↗
PubMed1990

AIDS education in rural Uganda--a way forward.

A survey of acquired immunodeficiency syndrome (AIDS)-related knowledge and attitudes was conducted during July and August 1988 in rural SW Uganda. The aim was to assess the impact of Uganda's AIDS education programme and to consider how future programmes could be more effectively implemented. Four hundred and seventy-six individuals aged 12-45 years were selected by a quota method, to form a sample stratified by age and sex. Mass AIDS education has successfully raised levels of knowledge but misconceptions persist. However, it has failed, firstly, to stress the urgency of AIDS as a personal issue, and secondly, to change negative attitudes toward people with AIDS: 57% would avoid or stigmatise an individual with AIDS. Unexpectedly, findings show that a correlation exists (P less than 0.05) between high levels of 'correct' beliefs and negative attitudes toward people with AIDS. To achieve future behavioural and attitude changes, possible ways forward for Ugandan AIDS education include involvement of HIV carriers in education, small-scale targetted approaches developed by active participation of the target group and through role playing of people with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1990

A retrospective study of marital discord in pilots: the USAFSAM experience.

This exploratory retrospective multi-case study investigates marital discord in USAF pilots as part of an overall concern with mission safety. Seventeen USAF School of Aerospace Medicine (USAFSAM) cases involving marital distress were reviewed, using a standardized format. Duration of martial discord ranged from 1-10 years with an average of 2.25 years. The most frequent problem noted was one of communication, with authoritarian or controlling styles predominating. The second most frequent conflict concerned occupational demands; both pilots and spouses complained about frequent work-related separations. Nine of ten distressed outcomes (i.e., separated or divorced) were initiated by the wife. We speculate that a pilot with an inflexible communication style who is not cognizant of his or her spouse's emotional needs is likely to exacerbate marital problems. The notion that marital distress may adversely affect a pilot's attention, generating performance decrements, underscores the importance of investigating elements of marital harmony in the pilot population. Based on our study and review of the literature, we suggest the USAF employ programs that: a) recognize the spouse's contribution to mission safety; b) increase spouse's awareness of mission requirements; c) enhance couple's communication; and d) improve stress management skills.

Adult↗
PubMed1986

Somatostatin, an inhibitor of ACTH secretion, decreases cytosolic free calcium and voltage-dependent calcium current in a pituitary cell line.

Somatostatin is a neurohormone peptide that inhibits a variety of secretory responses in different cell types. We have investigated the effects of somatostatin on calcium current and intracellular free calcium in AtT-20 cells, a pituitary tumor line in which the inhibitory actions of this peptide have been well characterized. At concentrations similar to those that inhibit adrenocorticotropic hormone (ACTH) release, somatostatin and its analogs reduced the levels of intracellular free calcium (as measured by the Quin-2 technique). Nifedipine and other blockers of voltage-dependent calcium channels also reduced cytosolic calcium levels. The effects of somatostatin and nifedipine were not additive, suggesting that somatostatin might inhibit calcium channels. Experiments using the whole-cell patch-clamp technique showed that somatostatin reduces voltage-dependent calcium current. The effects of somatostatin on cytosolic calcium and calcium current appear to be independent of its ability to reduce secretagogue-stimulated cAMP accumulation in these cells. We propose that the somatostatin-induced decrease in cytosolic calcium concentrations and the voltage-dependent calcium current are one of the mechanisms by which somatostatin suppresses ACTH release in AtT-20 cells.

Adrenocorticotropic Hormone↗
PubMed1985

Diaphanography in the diagnosis of breast cancer.

In diaphanography, a light source is applied to the breast to visualize lesions through a television camera sensitive to infrared light. Diaphanography and mammography were performed on 1,476 patients in a screening population. Twenty-six cancers in 24 patients were confirmed by biopsy; detection rates were 96% for mammography, 58% for diaphanography, and 62% for physical examination. Mammography was significantly more sensitive than either diaphanography or physical examination (p less than 0.005). Mammography detected 10 cancers that were missed at physical examination, whereas diaphanography detected five such lesions. It is concluded that diaphanography does not satisfy the criteria of a screening procedure, but because the examination is completely innocuous, it may serve as an adjunct to physical examination. In addition, the authors developed a breast model for diaphanography that appears to correlate with the human breast and demonstrates some of the physics and limitations of diaphanography.

Biopsy↗
PubMedDate not supplied

Thimerosal increases the responsiveness of the calcium receptor in human parathyroid and rMTC6-23 cells.

Parathyroid cells express a plasma membrane calcium receptor (CaR), which is stimulated by a rise in extracellular calcium concentration ([Ca2+]ext). A decreased sensitivity to [Ca2+]ext occurs in adenomatous parathyroid cells in patients with primary hyperparathyroidism, but the underlying functional mechanism is not yet fully understood. This study explored whether CaR responsiveness is influenced by increasing the affinity of IP3 receptors--a major signalling component of other G-protein-coupled receptors. The sulphydryl reagent thimerosal was used to increase the responsiveness of IP3-receptors. Quantitative fluorescence microscopy in Fura-2-loaded cells was used to investigate the effects of thimerosal on the cytoplasmic calcium concentrations ([Ca2+]i) in human parathyroid cells and to compare its effects in a rat medullary thyroid carcinoma cell line (rMTC6-23) also expressing CaR. During incubation in Ca(2+)-free medium, thimerosal 5 microM induced a rapid sustained rise in [Ca2+]i in human parathyroid cells and no further [Ca2+]i increase appeared in response to the CaR agonist Gd3+ (100 microM). Thimerosal 1 microM induced only slow and minimal changes of basal [Ca2+]i and allowed a rapid response to Gd3+ 20 nM (a concentration without effect in control cells). The slope of the thimerosal-induced [Ca2+]i responses was steeper following exposure to CaR agonists. In the presence of 1 mM [Ca2+]ext, thimerosal (0.5 microM) induced a sharp increase in [Ca2+]i to a peak (within 60 s), followed either by return to basal [Ca2+]i or by a plateau of slightly higher amplitude. Similar results were obtained using rMTC6-23 cells. Thimerosal increases the responsiveness to CaR agonists through modulation of the sensitivity of the IP3 receptor in both parathyroid and rMTC6-23 cells.

Adenoma↗