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1.
2.
Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
3.
Evidence of sustained skeletal benefits from impact-loading exercise in young females: a 3-year longitudinal study. 总被引:4,自引:0,他引:4
Jaana A Nurmi-Lawton Adam D Baxter-Jones Robert L Mirwald Jacki A Bishop Patricia Taylor Cyrus Cooper Susan A New 《Journal of bone and mineral research》2004,19(2):314-322
The skeletal effects from intensive exercise throughout puberty are undefined. Forty-five female gymnasts and 52 controls were studied over 3 years, including a heredity aspect. The effects of size, maturity, exercise, and diet were identified using a multilevel regression model. Results demonstrated sustained skeletal benefits resulting from exercise throughout all stages of pubertal development. INTRODUCTION: Weight-bearing exercise is beneficial for peak bone mass development. However, whether skeletal benefits achieved with exercise are maintained if training remains intensive throughout the pubertal years is not entirely clear. The influence of familial resemblance for bone mass remains undefined in physically active versus inactive children. The aim of this study was to investigate the long-term influences of impact-loading exercise on bone quantity and quality in young females after controlling for growth, maturation, and hereditary factors. MATERIALS AND METHODS: At baseline, 45 gymnasts (G) and 52 normally active controls (C) 8-17 years of age were recruited. Anthropometry, diet, physical activity, and quantitative ultrasound (QUS) were measured annually for 3 consecutive years. DXA scans of total body (TB) and lumbar spine (LS) bone mineral content (BMC) and density (BMD) were taken three times at 1-year intervals. A multilevel regression model was fitted, and the independent effects of body size, maturity, physical activity, and diet were identified over time. To assess heredity influences, 27 G mothers and 26 C mothers volunteered for cross-sectional measurements of anthropometry, QUS, and BMC/BMD. RESULTS AND CONCLUSIONS: Gymnasts were smaller and lighter (as were their mothers) than controls, but they had significantly higher QUS and axial and appendicular BMC and BMD, with > 170 g more bone mineral in TB across puberty (after adjustment for maturity [years from peak height velocity], height, weight, energy, and protein intake). Gymnasts had up to 24-51% higher BMC and 13-28% higher BMD, depending on skeletal site. These results provide evidence of sustained skeletal benefits from impact-loading exercise, which are unlikely to result entirely from heredity, throughout pubertal years. 相似文献
4.
Maxillary sinusitis in adults: an evaluation of placebo-controlled double-blind trials 总被引:1,自引:0,他引:1
BACKGROUND: In general practice, acute sinusitis is frequently diagnosed
and treated with antibiotics. OBJECTIVE: This study aimed to determine the
evidence for the effectiveness of antibiotic treatment in acute maxillary
sinusitis in adults by assessing the methodological quality of
placebo-controlled double-blind randomized trials. METHOD: An evaluation by
four raters through a 35-item scoring-scale for internal and external
validity of all placebo-controlled double-blind randomized trials on acute
sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five
trials were excluded because they were not placebo-controlled,
double-blind, randomized, or were carried out in patients with chronic
sinusitis or in children. The three remaining trials were performed in
different populations (one in general practice) between 1973 and 1978. Only
one study claimed superiority of antibiotic treatment. Different inclusion
criteria and major outcome measures were used by the authors. The
reliability of major outcome events was reported poorly or not at all and
in two studies outcome measures were clinically inappropriate. The studies
scored 30-62% of the maximum attainable score for internal validity and
10-20% for external validity. CONCLUSION: The effectiveness of antibiotic
treatment in acute maxillary sinusitis in a general practice population is
not based sufficiently on evidence.
相似文献
5.
Localization of proopiomelanocortin mRNA in functional subsets of neurons defined by their axonal projections 总被引:5,自引:0,他引:5
J N Wilcox J L Roberts B M Chronwall J F Bishop T O'Donohue 《Journal of neuroscience research》1986,16(1):89-96
In situ cDNA:mRNA hybridization is a technique that has been developed for the visualization of cDNA:mRNA hybrids in individual cells. To use this technique to answer questions of regulation in heterogeneous populations of cells in the brain, it must be combined with other procedures allowing for the identification of functional subgroups of neurons. We report here a procedure by which in situ cDNA:mRNA hybridization may be combined with retrograde axonal tracing using the fluorescent tracer fast blue. Using this technique, it now becomes possible to measure mRNA regulation in functional subsets of cells defined by their axonal projections. 相似文献
6.
The Student Training, Education and Practice for Dietetics (STEP‐DIET) CD‐ROM was developed at the University of Surrey to prepare dietetic students for the practical dietetic training component of their Nutrition/Dietetics degree. This study aimed to evaluate student response to the programme and its effectiveness as a teaching tool, based on the evaluation framework of D.L. Kirkpatrick (Evaluating a Course, 2nd edn. London, Kogan Page). Quantitative and qualitative methodologies were employed, with 41 dietetic students, separated by year group, completing questionnaires and taking part in six focus groups, at the University of Surrey. Student attitudes towards the instruction method and the STEP‐DIET programme itself were investigated, in conjunction with their perceived learning achievements. Students rated the programme highly in terms of design and content, however, there was a reluctance to accept computer‐assisted instruction (CAI) as a sole teaching method. A number of learning achievements relevant to dietetic practice were reported including a perceived increase in ability to conduct a dietetic interview and an increased understanding of the management of Type 2 diabetes. In general students reacted positively to the STEP‐DIET programme and it was perceived by students to be effective in preparing them for the practical component of their dietetic training. 相似文献
7.
Previously reported attenuation of skin postural vasoconstriction in women during the luteal menstrual cycle phase may be
due to a progesterone-mediated decrease in myogenic or veno-arteriolar (VAR) mechanisms. Skin perfusion was measured in the
shin and foot dorsum by Laser Doppler Fluxometry during leg dependency that increased vascular transmural pressure below (myogenic
constriction only) and above (myogenic and VAR) the 25 mmHg threshold for activation of the VAR, and during venous distension
to activate the VAR alone (cuff inflation to 50 mmHg). In six young women with normal menstrual cycles, vasoconstrictor responses
to all interventions did not differ between days 7–13 (follicular) and 18–23 (luteal) of the normal menstrual cycle when progesterone
levels were low and at their peak respectively. In eight women taking combined oral contraceptives (OC) and tested during
pill consumption days, reductions in foot skin perfusion were smaller (P = 0.05) than in the luteal phase of the normal cycle for leg dependency below (−36.9 ± 5.2% OC vs. −52.5 ± 7.8% luteal, mean ± S.E.M.)
and above (−43.7 ± 3.4% OC vs. −55.1 ± 4.8% luteal) the VAR threshold, and for venous distension (−53.1 ± 2.6% OC vs. 66.4 ± 5.5%
luteal). In women with normal menstrual cycles, impaired postural vasoconstriction may be confined to those who experience
pre-menstrual symptoms rather than a direct effect of endogenous hormones. Reduced vasoconstriction in the dependent foot
during OC use is consistent with the known vasodilator action of exogenous hormones and its long-term effects 相似文献
8.
J R Bishop J W Moul S A Sihelnik D S Peppas T S Gormley D G McLeod 《The Journal of urology》1992,147(2):386-388
We report an 18-month prospective study of 90 patients undergoing penile prosthesis implantation to evaluate a possible cause-and-effect relationship between degree of diabetic control and the risk of infection complicating the operation. Long-term diabetic control was objectively evaluated by measurement of the glycosylated hemoglobin of the patient, which is known to provide an objective value for degree of control for the preceding 60 to 90 days. Of 90 patients 5 (5.5%) had a periprosthetic infection requiring explantation and all infections occurred in the 32 diabetics (36%) in the population (p less than 0.009). Of the 32 diabetics 13 (41.1%) were poorly controlled with time as demonstrated by a glycosylated hemoglobin level of greater than 11.5% and 4 of the infections occurred in this group. Of the 19 remaining controlled diabetics (glycosylated hemoglobin level less than 11.5%) only 1 infection occurred. Therefore, infection occurred in 31% of the poorly controlled versus 5% of the adequately controlled patients (p less than 0.0003). Measurement of glycosylated hemoglobin values appears to be a useful tool to evaluate diabetic patients before implantation of a penile prosthesis. Patients with a glycosylated hemoglobin level of 11.5% or greater should be more optimally controlled before undergoing implantation in an effort to avoid infectious complications. 相似文献
9.
Cholinergically induced bronchoconstriction is thought to be a major cause of bronchospasm during anesthesia. We used tracheally intubated rabbits (4-mm endotracheal tube) stimulated with methacholine to assess the efficacy of beta-adrenergic agonist and anticholinergic treatment in reversing the increases in respiratory system resistance. Four groups were compared: (a) inhaled metaproterenol, 20 puffs via metered dose inhaler (0.65 mg/puff); (b) inhaled ipratropium bromide, 20 puffs from a metered dose inhaler (18 micrograms/puff); (c) 2 mg of intravenous atropine; and (d) no treatment after methacholine challenge as a control group. Methacholine increased respiratory system resistance from 0.041 +/- 0.001 (mean +/- SEM) to 0.098 +/- 0.006 cm H2O.mL-1.s-1 (P < 0.001). Whereas beta-adrenergic agonist treatment was ineffective in ameliorating bronchoconstriction, inhaled ipratropium bromide and atropine were highly effective, causing an 86%-88% reversal in the methacholine-induced increase in respiratory system resistance. Both these agents were also effective in improving dynamic compliance. We conclude that inhaled ipratropium bromide is effective in treating cholinergic bronchospasm even when administered via a small endotracheal tube and that the beta-adrenergic agonist metaproterenol is ineffective in rabbits in the face of maximal cholinergic stimulation. 相似文献
10.
R Snyder J Bishop G Brodie W Burns A Coates J Levi D Raghavan M Schwarz M Tattersall D Thomson 《Cancer treatment reports》1987,71(3):273-276
Epirubicin was studied in a phase I setting to find the maximum tolerated dose when given weekly for 3 of 4 weeks. Forty-one evaluable patients were treated in groups at doses increasing from 20 to 45 mg/m2. The highest dose level produced the maximum degree of myelosuppression (lowest neutrophil count, 1.9 X 10(9)/L; range, 0-3.7) recorded on Day 22. This was well-tolerated in this group of mainly pretreated patients. Nonhematologic side effects were minimal. This dose schedule allows a greater dose per unit time to be administered than other recommended schedules for epirubicin. 相似文献