Biomedical subjects

P Baldwin

Publications and source records attributed to P Baldwin.

At least 19 recordsLinked to original sources

PubMed2004

Evolution of blood parameters during weight loss in experimental obese Beagle dogs.

The effects of weight loss on hormonal and biochemical blood parameters were measured monthly [carnitine, creatinine, urea, free T4 (fT4), total T4 (TT4), plasma alkaline phosphatases (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), potassium and total proteins] or bimonthly [cholesterol, triglycerides, non-esterified fatty acids (NEFA), insulin-like growth factor I (IGF-I), glucose, insulin] in eight obese Beagles dogs fed either a high protein dry diet, DP (crude protein 47.5%, on dry matter basis) or a commercial high fibre diet, HF (crude protein 23.8%, crude fibre 23.3%). The dogs were allotted to two groups according to sex and body weight (BW) and they were respectively fed with the DP or the control HF diet during 12-26 weeks, until they reach their optimal BW. The plasma basal triglycerides and cholesterol concentrations were decreased by the two diets but the difference was only significant for the DP diet. The plasma mean NEFA concentration increased regularly over the period with the HF diet, without significant difference between the two diets. No effect of diet or weight loss was observed on plasma carnitine, urea, creatinine, ALP, AST, ALT, potassium, TT4, FT4, IGF-I, glucose and insulin. Weight loss induced a decrease in fT4 plasma concentration (p < 0.001). The high protein diet allowed a safe weight loss.

Animals↗

PubMed2002

Training teachers--changing practice?

A three-day course was designed to improve the skills of those who provide clinical training to medical students. This long-term follow up of past participants shows a sustained improvement to their skills, especially in terms of involving students in their own learning, and giving them positive feedback.

Clinical Competence↗

PubMed2001

Feasibility, reliability and validity of a new assessment form for use with basic surgical trainees.

BACKGROUND: To establish feasibility, reliability and validity of a newly designed basic surgical training (BST) assessment form. METHODS: The assessment form was evaluated among trainees on the South-east Scotland BST rotation over 18 months. Feasibility was indicated by response rate. Reliability was determined using test-retest analysis and internal consistency of each domain determined by Cronbach's alpha and item-total correlation. Construct validity was evaluated by determining improvement in performance after 1 year of training. RESULTS: Response rate was high (889 of 984 forms [90%]), with similar representation from all disciplines. A highly significant positive correlation was found between test-retest scores for all domains (rho: I, 0.736; II, 0.875; III, 0.671; IV, 0.826; V, 0.859; P = 0.0001 all domains, Spearman's). Internal consistency was excellent for each domain, with Cronbach's alpha ranging from 0.82 to 0.95. Item-total correlation coefficients were greater than the required 0.4 for all but one task. In 101 assessments carried out after 1 year of training, significant improvement in scores was found for all domains except clinical skills (time 0 to time 1 year median [interquartile range]: I, 81 [26 to 100] to 100 [100 to 100], P = 0.008; II, 17 [-19 to 52] to 72 [36 to 100], P = 0.015; III, 85 [51 to 100] to 100 [87 to 100], P = 0.018; IV, 82 [44 to 100] to 92 [69 to 100], P = 0.211; V, 27 [-33 to 64] to 76 [32 to 100], P = 0.004). CONCLUSIONS: The new assessment form is feasible, reliable and valid and would therefore be suitable for extended use with basic surgical trainees.

Clinical Competence↗

PubMed2001

Extending the general practice training year: experience of one model in Scotland.

OBJECTIVES: These were: to describe the implementation of a scheme to extend the general practice registrar component of vocational training to 18 months in Scotland; to determine the effect of the additional attachment on registrars' confidence and skill deficits, and compare changes in these parameters with a control group of registrars who did not extend their training, and to determine whether trainers required a different training style for experienced registrars. SUBJECTS: 35 registrars extending their training, their trainers, and 39 controls who did not extend their training. SETTING: Scottish training practices. METHODS: Pre-attachment and post-attachment questionnaires for registrars, triangulated by semistructured telephone interviews, and post-attachment questionnaires for trainers. RESULTS: Extended attachments were popular with registrars and with trainers, who felt they should be a normal part of training. Registrars with extended training declared themselves to have increased in confidence and addressed skill deficits better than controls. Projects completed were assessed as being of high quality. Trainers found 10% of registrars to have a remediable, important deficit in their skills. CONCLUSION: Extended attachments appear to improve registrar confidence and to address knowledge deficits. However, only a minority of registrars had important remediable knowledge deficits and while such attachments may be desirable they may not be essential for most registrars. Overall the outcome appears to have been positive, and supports those who have argued for a change in the proportion of time spent in general practice training, but the scheme is expensive and it is difficult to set a value on what has been gained. Future schemes should have clear training objectives and be tailored towards these.

Chi-Square Distribution↗

PubMed2001

Comparison of fluorescence and rinsing methods for assessing dermal exposure.

There are a number of methods of estimating dermal contamination. "Potential exposure" methods, such as patch and whole-body oversuit sampling, intercept the contaminant before it reaches the skin. "Actual exposure" measurements recover the contaminant from the skin by wiping, stripping, or rinsing, or, in the case of fluorescent tracer dye monitoring, assess it in-situ on the skin. These different methods can give rise to very different results. Comparison of methods is difficult, because they usually interfere within-subject. This presentation is a comparison of two compatible 'actual dermal contamination' measurement techniques. They are: (1) fluorescence monitoring of a tracer dye in-situ on the skin, using ultraviolet light and a video camera linked to an image processor; (2) rinsing of the skin to recover a metal tracer salt for later assay in solution. Several painting and spraying application tasks were carried out by a panel of volunteers who wore T-shirts, shorts, and open sandals. The exercises simulated domestic or nonoccupational tasks. Results showed excellent agreement, with discrepancies identified and explained. The good agreement of the two completely different, independent tracer methods for measuring skin contamination contributes to their mutual validation.

Environmental Exposure↗

PubMed1998

Dissociated pattern of activity in visual cortices and their projections during human rapid eye movement sleep.

Positron emission tomography was used to measure cerebral activity and to evaluate regional interrelationships within visual cortices and their projections during rapid eye movement (REM) sleep in human subjects. REM sleep was associated with selective activation of extrastriate visual cortices, particularly within the ventral processing stream, and an unexpected attenuation of activity in the primary visual cortex; increases in regional cerebral blood flow in extrastriate areas were significantly correlated with decreases in the striate cortex. Extrastriate activity was also associated with concomitant activation of limbic and paralimbic regions, but with a marked reduction of activity in frontal association areas including lateral orbital and dorsolateral prefrontal cortices. This pattern suggests a model for brain mechanisms subserving REM sleep where visual association cortices and their paralimbic projections may operate as a closed system dissociated from the regions at either end of the visual hierarchy that mediate interactions with the external world.

Adult↗

PubMed1998

The use of azathioprine in severe adult atopic eczema.

AIM: To evaluate the use of azathioprine in the treatment of severe adult atopic eczema and review the relevant literature. BACKGROUND: Effective treatment of severe adult atopic eczema may necessitate the use of agents such as systemic steroids, PUVA or cyclosporin, which are associated with significant morbidity. Azathioprine is an effective alternative which can induce disease remission and may be less toxic. METHODS: Ten patients treated with azathioprine 0.7-2.5 mg/kg per day for a minimum period of 12 months were evaluated in a retrospective follow-up study. RESULTS: Clearance or marked improvement was noted in eight patients; three of these later became refractory to the drug. Side-effects were few and were well-tolerated. One patient was found to have lymphoma 8 months after stopping treatment. CONCLUSION: Azathioprine is an effective and cheaper alternative to cyclosporin in the treatment of severe adult atopic eczema. Its long-term toxicity remains unclear.

Adult↗

PubMed1997

A phase I-II study of high-dose melphalan, mitoxantrone and carboplatin with peripheral blood stem cell support in patients with advanced ovarian or breast carcinoma.

The purpose of this study was to develop a high-dose chemotherapy (HDC) and peripheral blood stem cell (PBSC) regimen for treatment of patients with ovarian carcinoma that could be administered in an outpatient setting. Fourteen patients with advanced ovarian (n = 9) or breast (n = 5) carcinoma, who had failed conventional chemotherapy, were entered into a dose-escalation trial to determine the maximum tolerated dose (MTD) of carboplatin that could be administered with fixed doses of melphalan (160 mg/m2) and mitoxantrone (50 mg/m2). Twenty-five additional patients were included in a phase II trial at the MTD. Two of two patients had grade 4 severe regimen-related toxicities (RRT), one fatal, at a dose level of 1600 mg/m2. Two of 29 patients (6.9%) treated at the MTD (carboplatin, 1400 mg/m2) died of RRT. All three patients who died of toxicity had a calculated AUC for carboplatin >30 mg/ml/min. Thirty-one patients with ovarian cancer who had failed chemotherapy were treated, 24 at the MTD. Fourteen of 20 patients (70%) with ovarian carcinoma with evaluable disease achieved a CR and seven (35%) are alive disease-free a median of 20 months (range, 7-26). Five of seven patients with ovarian cancer who had failed chemotherapy but were rendered clinically disease-free following surgery survive without progression a median of 13 months (range, 9-19). Eight of 16 (50%) platinum-resistant and 4/12 (33%) platinum-sensitive patients with ovarian cancer survive disease-free.

Adult↗

PubMed1997

Regional cerebral blood flow throughout the sleep-wake cycle. An H2(15)O PET study.

To assess dynamic changes in brain function throughout the sleep-wake cycle, CBF was measured with H2(15)O and PET in 37 normal male volunteers: (i) while awake prior to sleep onset; (ii) during Stage 3-4 sleep, i.e. slow wave sleep (SWS); (iii) during rapid eye movement (REM) sleep; and (iv) upon waking following recovery sleep. Subjects were monitored polysomnographically and PET images were acquired throughout the course of a single night. Stage-specific contrasts were performed using statistical parametric mapping. Data were analysed in repeated measures fashion, examining within-subject differences between stages [pre-sleep wakefulness-SWS (n = 20 subjects); SWS-post-sleep wakefulness (n = 14); SWS-REM sleep (n = 7); pre-sleep wakefulness-REM sleep (n = 8); REM sleep-post-sleep wakefulness (n = 7); pre-sleep wakefulness-post-sleep wakefulness (n = 20)]. State dependent changes in the activity of centrencephalic regions, including the brainstem, thalamus and basal forebrain (profound deactivations during SWS and reactivations during REM sleep) are consistent with the idea that these areas are constituents of brain systems which mediate arousal. Shifts in the level of activity of the striatum suggested that the basal ganglia might be more integrally involved in the orchestration of the sleep-wake cycle than previously thought. State-dependent changes in the activity of limbic and paralimbic areas, including the insula, cingulate and mesial temporal cortices, paralleled those observed in centrencephalic structures during both REM sleep and SWS. A functional dissociation between activity in higher order, heteromodal association cortices in the frontal and parietal lobes and unimodal sensory areas of the occipital and temporal lobes appeared to be characteristic of both SWS and REM sleep. SWS was associated with selective deactivation of the heteromodal association areas, while activity in primary and secondary sensory cortices was preserved. SWS may not, as previously thought, represent a generalized decrease in neuronal activity. On the other hand, REM sleep was characterized by selective activation of certain post-rolandic sensory cortices, while activity in the frontoparietal association cortices remained depressed. REM sleep may be characterized by activation of widespread areas of the brain, including the centrencephalic, paralimbic and unimodal sensory regions, with the specific exclusion of areas which normally participate in the highest order analysis and integration of neural information. Deactivation of the heteromodal association areas (the orbital, dorsolateral prefrontal and inferior parietal cortices) constitutes the single feature common to both non-REM and REM sleep states, and may be a defining characteristic of sleep itself. The stages of sleep could also be distinguished by characteristic differences in the relationships between the basal ganglia, thalamic nuclei and neocortical regions of interest.

Adult↗

PubMed1997

Influence of a blend of fructo-oligosaccharides and sugar beet fiber on nutrient digestibility and plasma metabolite concentrations in healthy beagles.

OBJECTIVE: To evaluate effects of a blend of fructo-oligosaccharides and sugar beet fiber (4:1) at 3 incorporation rates on nutrient digestibility and plasma glucose, insulin, alpha-aminonitrogen, urea, cholesterol, and triglycerides concentrations measured weekly in nonfed dogs and during a 360-minute period after a meal. ANIMALS: 8 castrated 1- to 1.4-year-old young adult male Beagles weighing 10.0 to 13.5 kg. PROCEDURE: Diets containing 2 incorporation rates of a blend of fructo-oligosaccharides and sugar beet fiber (5 and 10% on a dry matter basis [diets B and C, respectively]) were compared with a control diet without additional fiber (diet A). The 3 diets were evaluated for ability to modify digestibility of dry and organic matter, protein, fat, and ash and for effects on plasma glucose, insulin, alpha-aminonitrogen, urea, cholesterol, and triglycerides concentrations. Each diet was fed for 6 weeks; plasma samples were collected weekly before feeding and after feeding on the last day of the period. During 1 week at the end of the 6-week period, dogs were kept in metabolic cages. Each period of the block was followed by a 4-week washout period. RESULTS: Incorporating the blend of fructo-oligosaccharides and sugar beet fiber in the diet was associated with greater passage of wet feces (diets B and C) and lower protein digestibility (diet C). Postprandial glucose (diet C), urea (diets B and C) and triglyceride (diets B and C) concentrations were significantly (P < 0.01) decreased. Weekly preprandial measurements were characterized by decreased urea (diets B and C), cholesterol (diet C), and triglycerides (diets B and C) concentrations (P < 0.001). CONCLUSION: Chronic consumption of fermentable fiber is associated with mildly decreased protein digestibility and with metabolic effects in nonfed or fed dogs. CLINICAL RELEVANCE: A blend of fructo-oligosaccharides and sugar beet fiber should be tested as a dietary aid for treatment of chronic diseases, such as diabetes mellitus or hyperlipidemia, in dogs.

Animals↗

PubMed1996

North American experience with the Perma-Flow prosthetic coronary graft.

BACKGROUND: The Perma-Flow prosthetic coronary graft is a 5-mm polytetrafluoroethylene tube into which is incorporated a Venturi flow restrictor. An aorto-superior vena caval fistula is created and coronary anastomoses are constructed proximal to the resistor in side-to-side fashion, where arterial pressure is maintained. From November 1992 through December 1995, eight investigational centers in North America have implanted this graft in 40 patients with inadequate autologous alternatives. METHODS: Patients were selected for inclusion in this study if coronary artery bypass grafting was required and adequate autologous conduit to complete revascularization was not available. Operative data were completed by the implantating surgeon and referred to a central center, the Minneapolis Heart Institute, for correlation. Follow-up was conducted by data coordinators at each institution, and follow-up data were obtained directly from these coordinators for inclusion in the study. RESULTS: Patient age ranged from 53 to 82 years, and 15 patients were undergoing reoperations (38%). On each Perma-Flow graft one to four coronary side-to-side anastomoses were constructed. In addition, left internal mammary artery (n = 26), greater saphenous vein (8), right internal mammary artery (4), and gastroepiploic artery (4) were used to complete revascularization. Aortic (2) or mitral valve replacement (1) was also carried out. There were seven operative deaths (18%) and two late deaths (4 and 6 months). After 1 to 37 months (mean, 13 +/- 9 months) of follow-up, 29 of 31 surviving patients are asymptomatic. Echocardiographic heart size has not increased from the postoperative value, indicating limited volume load has not affected heart size. Protocol catheterization (n = 32) in 28 patients 1 week to 1 year postoperatively revealed 7 of 73 studied coronary anastomoses (9.5%) and two distal extensions and resistors were occluded (7%). In 1 patient during sternal debridement at 1 year, no flow was found in the graft. CONCLUSIONS: The Perma-Flow graft is a useful adjunct to complete revascularization in patients with deficient autologous conduit.

Aged↗

PubMed1995

Validation of creatine, glycogen and L-(+)-lactate determination in biopsy samples of bovine Musculus diaphragma.

Whereas reliable measurements of diaphragmatic force and electrical activity are now available in calves, evidence that substrate contents in the bovine diaphragm can be accurately measured is still lacking. The purposes of the present study were therefore a) to describe and test the reliability of methods and procedures used for sampling, lyophilisation, extraction and dosage of muscular lactate, glycogen and creatine contents and b) to report the variation in their levels found along the bovine diaphragm and among individuals. The repeatability of the results yielded by a) assaying the extracts, b) processing and assaying the extracts and c) taking samples at different sites in the muscle was assessed. Neither assay, nor processing effects were significant (P < or = 0.05). Substrates were found to be homogeneously distributed within the two muscles studied. Substrate contents expressed per unit of muscle weight or total creatine were neither more or less variable than when expressed per unit of dry matter.

Animals↗

PubMed1994

Gender-related differences in regional cerebral glucose metabolism in normal volunteers.

Positron emission tomography studies have correlated changes in the cerebral metabolic rate of glucose utilization (CMRglu) with symptoms of depression, aggression, impulsivity, and hyperactivity. Psychiatric disorders in which these symptoms are manifested are disproportionately represented among the sexes. We evaluated gender differences in regional CMRglu in control subjects (21 men and 18 women) with particular interest in the global, orbital frontal, and left anterolateral prefrontal cortical (LAPFC) CMRglu. A trend was present for global CMRglu to be greater in women than in men. Regional CMRglu was lower in men than in women in the orbital frontal area. No differences were observed in the LAPFC region.

Adult↗

PubMed1990

Animal performance, plasma hormones and metabolites in Holstein and Belgian Blue growing-fattening bulls.

Six Holstein (light-muscled type) and six Belgian Blue bulls (double-muscled type) were fed a finishing diet. Average daily gain was 1.36 kg for the Holstein bulls vs 1.24 kg for the Belgian Blue bulls (P less than .05). Holstein bulls consumed more feed (2.3 vs 1.8 kg/100 kg body weight, P less than .001) than the Belgian Blue bulls. The dressing percentage (55.4 vs 65.8%, P less than .001) and the proportion of muscle (56.1 vs 71.3%, P less than .001) in the carcass were less, whereas the proportions of adipose tissue (28.3 vs 15.4%, P less than .001) and bone (15.7 vs 13.4%, P less than .05) were higher in the Holstein bulls. Plasma creatinine determined in samples obtained once a week was lower (11.0 vs 20.3 mg/liter, P less than .001) in the Holstein bulls. In contrast, Holstein bulls tended to produce more triiodothyronine (2.3 vs 1.8 nM, P less than .10), tetraiodothyronine (71.9 vs 54.7 nM, P less than .10) and insulin-like growth factor I (IGF-I; 340 vs 205 ng/ml, P less than .20) than the Belgian Blue bulls. Growth hormone, insulin, IGF-I and testosterone were measured at 20-min intervals during two 24-h periods. In wk 6, Holstein bulls tended to produce more growth hormone than the Belgian Blues, as indicated by higher total peak area (3,185 vs 2,431 ng), peak amplitude (34.1 vs 22.6 ng/ml, P less than .10) and baseline (4.6 vs 3.3 ng/ml, P less than .20). In wk 27, the trends were opposite.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1986