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Biomedical subjects

M O'Brien

Publications and source records attributed to M O'Brien.

358 records · Page 20Linked to original sources
PubMedDate not supplied

Association of bone mineral density and pediatric fractures.

Bone mineral density in the lumbar spine and the left femoral neck was measured for a group of 17 children, 3-14 years of age, who had sustained traumatic fractures. Children with any signs of metabolic bone disease were excluded from the study. Identical measurements were made on an age- and sex-matched control population using dual photon absorptiometry. Analysis of bone mineral measurements revealed that there were no statistically significant differences between the lumbar and femoral neck densities of the two groups. The results indicate that reduced bone density is unlikely to play a significant role in acute traumatic pediatric fractures.

Adolescent↗
PubMedDate not supplied

Amelioration of cerebral ischemia by prior treatment of hypertension.

Bilateral carotid artery ligation was made in 14 SHR while rCBF was serially measured with hydrogen clearance. Blood pressure was controlled with an intra-arterial catheter connected to a reservoir. There was no significant correlation between blood pressure and rCBF prior to the carotid occlusion, but afterwards there was a progressively increasingly negative correlation between mean arterial blood pressure and rCBF with time. These observations indicate that the severity of ischemia is greater in the presence of hypertension if the hypertension is present prior to the onset of ischemia and the blood pressure maintained constant thereafter.

Animals↗
PubMedDate not supplied

The portfolio: how was it for you? Views of F2 doctors from the Mersey Deanery Foundation Pilot.

A study was conducted between August 2004 and August 2005 to explore the experiences of Foundation year 2 (F2) trainees who used the learning portfolio on the Mersey Deanery pilot scheme. Seventy-three trainees (77%) reported receiving their portfolio during their induction. In their first four-month placement, 90 trainees (96%) completed the two case-based discussions, 80 (87%) the three mini clinical examinations and 92 (97%) the two direct observation of practical procedures. The number of trainees who felt there was an opportunity to make a record of and analyse clinical critical incidents and critical incidents related to professional behaviour was only 32 (35%) and 13 (15%) respectively. Free text responses suggested that trainees appreciate the portfolio but that an understanding of its content and purpose, particularly by educational supervisors, is paramount to its success.

Clinical Competence↗
PubMedDate not supplied

Performance and clinical use of a convertible hemodialysis (HD) - ultrafiltration (UF) system.

A hemodialysis-ultrafiltration system has been developed and evaluated. It may be used either as a conventional hemodialyzer or as a nondialytic ultrafilter. When used as a dialyzer an ultrafiltration controller is required to fix ultrafiltration rate at the desired level. Rates of low molecular solute removal are compatible with those observed in commercially available artificial kidney systems, higher clearances are obtained for middle molecules, and the rate of ultrafiltration can be controlled within narrowly prescribed limits.

Blood Flow Velocity↗
PubMedDate not supplied

Mean flow velocity in the right common carotid artery before and after maximal exercise.

The effect of exercise on mean flow velocity (MFV) in the right common carotid artery (RCC) was studied using pulsed Doppler ultrasound. MFV was measured at rest and at 2 minutes intervals after a 6 minute rowing ergometer test. Age-related maximum heart rate of 190 +/- 10 beats.min-1, maximum respiratory rate of 60 +/- 5 breaths.min-1, and postexercise lactate level of greater than 8 mmol.l-1 were the criteria used to define maximal exercise. The control group comprised 13 healthy, active males, mean age 19.8 years, with 19 healthy oarsmen, mean age 19.9 years, in the exercise group. At rest, MFV in the RCC was found to be 18.6 +/- 5.6 and 16.4 +/- 6.3 cm.min-1 in the control and exercise groups respectively. After exercise, MFV decreased to 21% of its resting value and remained significantly reduced (posthoc tests, Newman Keuls at alpha = 0.01) until 14-16 minutes of recovery. Mean systemic arterial pressure (MSAP) remained within normal limits. Mean age-related maximum heart rate was 182 +/- 3 beats.min-1, respiratory rate 58 +/- 3 breaths.min-1, and postexercise serum lactate 20.2 +/- 3.5 mmol.l-1 which satisfied the criteria for maximal exercise. In this group of young males, MFV in the RCC decreased markedly after maximal exercise and remained significantly reduced for a long period. This sustained reduction in MFV has not previously been described and is most likely due to vasoconstriction in distal cerebral resistance arterioles mediated by hypocapnia and autonomic activity.

Adult↗
PubMedDate not supplied

Bone density profiles and osteoporosis incidence in Irish females.

1725 Irish females aged 15-70+ were included in this analysis to establish the group bone mineral density (BMD) profiles. Each subject was screened for 27 risk factors by questionnaire. Subjects were segregated into normal (N) and non-normal (NN) subgroups on the basis of the questionnaire. BMD of lumbar spine and hip were measured by dual energy X ray absorptiometry (DEXA). A substantial difference in BMD at all sites was observed between subgroups even following adjustment for body mass index and years of exposure to oestrogen. In the subgroup designated as non-normal 42%, 54%, 72% and 69% of those studied had spinal BMD levels > 2SD below mean peak at 55-59, 60-64, 65-69 and 70+ respectively. In comparison, similar age cohorts in the subgroup designated normal were 26%, 46%, 44% and 68% respectively. A marked difference was also observed in the younger age groups (15-34) where the percentage of individuals with spinal BMD levels > 2SD below mean peak was < 1.9% for N and 18.8% for NN. The results of this study suggest that the use of a questionnaire may be a valuable low cost screening tool in the younger groups.

Adolescent↗
PubMedDate not supplied

Gemcitabine.

There is widespread consensus that a plateau has been reached in the effectiveness of known DNA interactive drugs against most malignancies. Combination treatments, dose intensification and schedule alterations (e.g. infusional and neoadjuvant treatments) represent exciting research opportunities and possibly the means for making meaningful progress. However, frustration with the slow pace of even these most novel approaches has led to a search for newer drug targets and great expectations of new drugs.

Antimetabolites, Antineoplastic↗