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Biomedical subjects

J M Blake

Publications and source records attributed to J M Blake.

At least 19 recordsLinked to original sources
PubMed2005

Does continuous passive motion during keyboarding affect hand blood flow and wrist function? A prospective case report.

The purpose of this prospective case report was to evaluate the use of a keyboard platform device that uses continuous passive motion (CPM) on vascular flow to the hand for clerical employees who perform daily keyboarding tasks. Subjects were two female volunteers, one symptomatic of carpal tunnel syndrome (CTS), who were employed in clerical positions and perform daily keyboarding tasks for most of their workday. Data collection consisted of baseline and follow-up measurements at 6 weeks, including: 1) screening for symptoms based on the Carpal Tunnel Function Disability Form, 2) evaluation using standard physical therapy examination and assessment techniques, including modified Semmes- Weinstein monofilament testing, 3) a typing productivity test, and 4) Doppler ultrasound examination to quantify vascular flow at the wrist. Results revealed that both subjects demonstrated an overall increase in both radial and ulnar blood flow velocity with no decrement in typing productivity. The symptomatic subject also demonstrated an overall improvement of 10 wpm in the typing tests, a decrease in her disability score and symptom severity, and improvement in function. Results suggest that use of CPM as a non-intrusive ergonomic intervention may be used to treat, as well as prevent, carpal tunnel-like symptoms in those who keyboard.

Carpal Tunnel Syndrome↗
PubMed1999

Changes in spine and radius bone density during long-term hormone replacement.

Lumbar spine and mid-radius bone mineral density was measured repeatedly in 48 postmenopausal women who completed 7 years of taking either a 500 mg x day(-1) calcium supplement (n = 22) or calcium supplementation with hormone replacement therapy. The hormone replacement was either a low dose (n = 15) or a moderate dose (n = regime. The purpose of the measurements was to establish the long-term pattern of change in bone mineral mass produced by continued hormone replacement. The calcium-only group lost bone mineral mass at the radius, while the spine, bone was preserved. Low dose hormone replacement preserved radius bone. Moderate dose replacement increased bone mineral mass at the spine and preserved radius bone.

Aged↗
PubMed1997

Characterization of the infection of Aedes albopictus cell clones by Sindbis virus.

We have investigated the infection of Aedes albopictus (mosquito) cell clones by Sindbis virus. Variation in the multiplicity of infection (MOI) from ranges of 50-0.00005 pfu/cell was determined to have no effect on the progression of the infection to high acute phase titer, suggesting that intracellular factors alone are responsible for the restriction of virus production seen as the infection enters the persistent phase: While persistently infected (over 1 year post infection) cell clones are morphologically indistinct from uninfected cells, they do display a uniform 30% reduction in growth rate compared with uninfected cells of the same clone. Using flow cytometry-based DNA content analysis, we found that persistent Sindbis virus infection induces distinct cytological effects on these cells, including an increase in apoptosis and polyploidy in one clone and cell cycle phase effects in another. Finally, the observation that the number of cells in persistently infected cell cultures which are productively infected closely approximates the number of cells dying by apoptosis prompted us to investigate the role that cell death may play in the maintenance of the persistent infection. Persistently infected cell cultures which were artificially induced into apoptosis by short 45 degrees C heat treatments do not display increased Sindbis virus production. This result does not support the hypothesis that infection sensitivity induced by random apoptosis in persistently infected cell cultures is responsible for the long-term maintenance of the persistent infection.

Acute Disease↗
PubMed1996

Introducing progress testing in McMaster University's problem-based medical curriculum: psychometric properties and effect on learning.

BACKGROUND: The progress test (or Quarterly Profile Examination), invented concurrently by the University of Missouri-Kansas City School of Medicine and the University of Limburg, is used to provide useful summative and formative judgments about students' knowledge without distorting learning. All students in all classes sit the same examination at regular intervals through the year, and their individual progress is noted. This paper reports on four years' experience with a progress test, the Personal Progress Index (PPI), at the McMaster University Faculty of Health Sciences. METHOD: The PPI, a 180-item multiple-choice test with items drawn from all disciplines of medicine, is administered to medical students in all three classes three times per year. Individual feedback is provided, and accumulated student performance is determined for summative purposes. This paper examines extensive evidence of reliability, validity, and effect on student learning, using samples from the entering classes of 1992-1995 (a total of 400 students). RESULTS: Reliabilities across test administrations (within classes) ranged from .46 to .63. The PPI demonstrated strong construct validity, with highly significant statistical tests of differences between classes and changes within classes on successive administrations. The predictive validity of the PPI, i.e., whether it could predict performance on the licensing examination of the Medical Council of Canada, increased monotonically from a correlation of .12 for the first test administration one month into medical school to a high of about .60 for the cumulative score across all administrations three months prior to the examination. CONCLUSION: The PPI seems to be performing as intended, with students showing growth in performance across the three years of the MD program. Additional benefits are that many more students now self-refer for remediation (based on low PPI scores) and that the consistent relative performances of individual students across test administrations allow for the identification of students who have severe and persistent problems.

Analysis of Variance↗
PubMed1996

Postmenopausal bone mineral density: relationship to calcium intake, calcium absorption, residual estrogen, body composition, and physical activity.

Physical and lifestyle data were collected from 62 postmenopausal women who had declined hormone replacement therapy. Potential predictor variables were examined for their associations with bone mineral density (BMD) of the lumbar spine and femoral neck as assessed by dual x-ray absorptiometry. Body weight demonstrated the strongest association with lumbar BMD; lean body mass demonstrated the strongest association with femoral BMD. Together with the natural logarithm of the number of years since menopause (ln YSM) these anthropometric variables explained 36 and 34% of the variability of femoral and lumbar BMD, respectively. Serum estradiol levels demonstrated a weak positive association with BMD, which lost statistical significance after adjustment for body mass. Similarly, cardiovascular fitness was positively associated with femoral BMD prior to but not following adjustment for body mass. Controlling for years since menopause and body mass, the product of dietary calcium and calcium absorption demonstrated a weak positive correlation with femoral BMD (partial r = 0.30). The intake of tea was positively and significantly associated with both bone density measurements. In multiple regression analysis, femoral BMD was best explained by the lean body mass, ln YSM, and the daily intake of tea (r2 = 0.50). Similarly, lumbar BMD was best explained by body weight, ln YSM, and intake of tea (r2 = 0.44). Body mass is a major predictor of postmenopausal bone density at the hip and spine. A positive association between dietary calcium and BMD was detected only by taking into account the intestinal absorptive efficiency.

Absorption↗
PubMed1996

Rehabilitation for children--parents can't do it all.

Management of disabling conditions in children differs from that for adults, with ongoing needs related to growth and development. Parents also vary in their ability to deal with the demands placed on the family by a child with a disability. Different disabling conditions require many of the same kinds of therapies, with more emphasis on some. Functional goals include mobility, communication, independence in activities of daily living, education and eventual appropriate vocational planning. Consultation, outpatient therapy, or intensive, inpatient management may be appropriate at different times. A rehabilitation team approach with other specialists as needed can assist the child, family, and school to achieve the best outcome possible.

Adolescent↗
PubMed1995

Hormone replacement therapy may reduce the return of endogenous lead from bone to the circulation.

Hormone replacement therapy (HRT) in postmenopausal women suppresses the increase in bone resorption expected as circulating levels of endogenous estrogen decline. We tested the hypothesis that bone lead content might remain elevated in women on HRT. Fifty six women who at recruitment were on average 35 years postmenopausal were placed on calcium supplementation. Six months later 33 of these women were prescribed either low dose or moderate dose hormone replacement in addition to the calcium supplementation. After approximately 4 years of hormone replacement, lead content was measured at the tibia and calcaneus by in vivo fluorescence excitation, and lead concentrations were measured in serum, whole blood, and urine. Women not taking hormones had significantly lower lead concentrations in cortical bone compared to all women on HRT (p = 0.007). Tibia lead content (mean +/- SD) for women on calcium only was 11.13 +/- 6.22 microgram/g bone mineral. For women on HRT, tibia bone lead was 19.37 +/- 8.62 micrograms/g bone mineral on low-dose HRT and 16.87 +/- 11.68 micrograms/g bone mineral on moderate-dose HRT. There were no differences between groups for lead concentrations measured in trabecular bone, whole blood, serum or urine. Hormone replacement maintains cortical bone lead content. In women not on HRT, there will be a perimenopausal release of lead from bone.

Bone and Bones↗
PubMed1994

FISH detection of Wolf-Hirschhorn syndrome: exclusion of D4F26 as critical site.

Wolf-Hirschhorn syndrome (WHS) is due to a deletion in the terminal band of 4p16.3. Among loci that have been involved in deletions are D4S98, D4S95, D4S125, D4F26, as shown by PCR typing, Southern blot hybridization, and/or fluorescent in situ hybridization (FISH). Currently, FISH detection of WHS is predicted upon the deletion of the D4F26 locus with failure to hybridize to pC847.351, a commercially available cosmid probe. A WHS patient is shown to have an interstitial deletion, by hemizygosity at D4S98 and D4S95 but not at D4F26. This suggests that the tip of 4p, specifically D4F26, is not a critical deletion site for WHS.

Chromosome Deletion↗
PubMed1994

Effects of 2 years of hormone replacement upon bone mass, serum lipids and lipoproteins.

The objective of this study was to measure the effects on postmenopausal women of 2 years of either a low dose or a moderate dose regimen of hormone replacement upon bone mass and serum cardiovascular risk factors. After 6 months of calcium supplementation, 75 women chose to add hormone replacement or to remain on calcium. Those choosing hormones were randomised to either 0.3 mg/day equine estrogen and 2.5 mg/day medroxyprogesterone or 0.625 mg/day equine estrogen, days 1-25, and 5 mg/day medroxyprogesterone, days 16-25. On calcium only, lumbar spine bone mineral content and radius bone mass fell. Serum concentrations of cholesterol and triglycerides increased while HDL concentration fell. The low dose continuous regime reduced whole body bone turnover and prevented the age related reductions in bone mass and serum cardiovascular risk profile. The moderate dose regimen reduced whole body bone turnover and increased lumbar spine bone mass. Total serum cholesterol was unchanged while HDL levels increased, LDL levels fell and triglyceride concentration increased.

Adult↗
PubMed1993

Prepubertal ovarian cyst formation: 5 years' experience.

OBJECTIVE: To document the frequency of ovarian cyst formation in the prepubertal female and to report on the clinical implications of these cysts. METHODS: We evaluated cases from a retrospective chart review of prepubertal females with ovarian cysts. RESULTS: Over a 5-year period, 1818 ultrasound studies were completed in prepubertal females, from which 99 patients were identified as having ovarian cysts. The majority (82 of 99, 83%) were small, unilocular cysts averaging 2-3 mm in diameter. The incidence of these small cysts ranged at 2-5% in females between birth and age 8. Large ovarian cysts (ie, greater than 2 cm in diameter) are rare in young girls over age 2, with most occurring within the first year of life. Of the 17 large ovarian cysts, two presented with torsion and both were complex on ultrasound examination. Five (29%) of the large ovarian cysts were treated conservatively and demonstrated regression on follow-up; these were unilocular cysts. Although functioning cysts resulting in precocious pseudopuberty are expected to be rare, we identified five cases (5%) in our series. CONCLUSIONS: Small, unilocular ovarian cysts less than 1 cm in diameter are found in prepubertal females with a frequency of 2-5% and are clinically insignificant. Ovarian cysts greater than 2 cm are rare. Unilocular ovarian cysts less than 5 cm may be followed conservatively with ultrasound surveillance until regression, without a major risk of torsion. Ovarian cysts associated with precocious pseudopuberty are generally larger than 2 cm and may be recurrent.

Child↗
PubMed1976

EB virus antibody and infectious mononucleosis in a boarding school for boys.

A study of EB virus antibody was undertaken in a boarding school for boys between 11 and 18 years of age; 35% of boys had EBV antibody when first sampled and a small number acquired antibody each year. Some of these boys had had no recorded illness during the period before the first positive sample and some developed classic infectious mononucleosis which was accompainied by a positive heterophil antibody test and detection of EB virus specific IgM. In a school of 800 boys there were 13 cases of infectious mononucleosis in four years.

Adolescent↗