Home About us Contact
|
Home About us Contact | ||
|
|
||
Flow Studies (flow + studies)
Selected AbstractsA Method for the Automated Assessment of Temporal Characteristics of Functional Hemispheric Lateralization by Transcranial Doppler SonographyJOURNAL OF NEUROIMAGING, Issue 3 2004M. Deppe ABSTRACT Background and Purpose. Transcranial Doppler sonography (TCD) can guide and complement investigations based on functional magnetic resonance and positron emission tomography imaging by providing continuous information on cerebral perfusion changes correlated to cerebral activation. So far, however, the role of functional TCD has been limited by a lack of sensitivity.Methods. Here, the authors present an outline of a method that increases the potential of TCD to detect perfusion changes within a vascular territory. Sensitivity on the order of 1% can be achieved by transformation of Doppler envelope curves, which accounts for systemic quasi-periodic and irregular spontaneous blood flow modulations and artificial disturbances related to the recording. A statistical technique is introduced that allows the automatic detection of time periods of significant hemispheric lateralization in evoked flow studies. Furthermore, an index of laterality is defined quantifying the extent of hemispheric dominance during stimulus processing.Results and Discussion. The analysis technique described in this article has been successfully employed in recent examinations on vision, motor activation, language, language recovery, and other cognitive tasks. Conclusion. The novel functional TCD technique permits valid and reproducible assessments of the temporal characteristics of functional hemispheric lateralization. [source] Fat-tailed gene flow in the dioecious canopy tree species Fraxinus mandshurica var. japonica revealed by microsatellitesMOLECULAR ECOLOGY, Issue 10 2006S. GOTO Abstract Pollen flow, seed dispersal and individual reproductive success can be simultaneously estimated from the genotypes of adults and offspring using stochastic models. Using four polymorphic microsatellite loci, gene flow of the wind-pollinated and wind-seed-dispersed dioecious tree species, Fraxinus mandshurica var. japonica, was quantified in a riparian forest, in northern Japan. In a 10.5-ha plot, 74 female adults, 76 male adults and 292 current-year seedlings were mapped and genotyped, together with 200 seeds. To estimate dispersal kernels of pollen and seeds, we applied normal, exponential power, Weibull, bivariate t -distribution kernels, and two-component models consisting of two normal distribution functions, one with a small and one with a large variance. A two-component pollen flow model with a small contribution (26.1%) from short-distance dispersal (, = 7.2 m), and the rest from long-distance flow (, = 209.9 m), was chosen for the best-fitting model. The average distance that integrated pollen flows inside and outside the study plot was estimated to be 196.8 m. Tree size and flowering intensity affected reproduction, and there appeared to be critical values that distinguished reproductively successful and unsuccessful adults. In contrast, the gene flow model that estimated both pollen and seed dispersal from established seedlings resulted in extensive seed dispersal, and the expected spatial genetic structures did not satisfactorily fit with the observations, even for the selected model. Our results advanced small-scale individual-based parentage analysis for quantifying fat-tailed gene flow in wind-mediated species, but also clarified its limitations and suggested future possibilities for gene flow studies. [source] Characterization of microsatellite markers in Fagus sylvatica L. and Fagus orientalis LipskyMOLECULAR ECOLOGY RESOURCES, Issue 1 2003R. Pastorelli Abstract Using an enrichment procedure, we cloned microsatellite repeats from European beech (Fagus sylvatica L.) and developed primers for the amplification of microsatellite markers. Six polymorphic loci were characterized which produced 3,21 alleles in 70 individuals from one Italian population, with an observed heterozygosity between 0.58 and 0.85. All six loci amplified fragments which were polymorphic in the closely related species, Fagus orientalis, also. Owing to their very high degree of variation, these markers should be very useful in gene flow studies of these species. [source] Early transient leg swelling at the side of renal transplant in two childrenPEDIATRIC TRANSPLANTATION, Issue 1 2006L. Koster-Kamphuis The swelling was located at the side of the renal transplant. The swelling was caused by the compression of the iliac vein by the renal transplant combined with perirenal fluid collection. Doppler flow studies allow the exclusion of thrombosis as an explanation for the swelling. An aggressive treatment should be avoided. However, anticoagulation is required. [source] Distraction produces an increase in pain-evoked anterior cingulate activityPSYCHOPHYSIOLOGY, Issue 4 2004Robert Dowman Abstract This study examined the effects of distraction on pain-evoked activity in the anterior cingulate cortex (ACC). Twenty-eight healthy adults were given painful electrical stimulation of the sural nerve during an attend condition, where they rated the subjective magnitude of each electrical stimulus, and during a distraction condition, where they performed an arithmetic distraction task. The magnitude of the pain-evoked ACC activity was estimated from the dipole source localization analysis of the somatosensory evoked potential. Subjective pain ratings were smaller and pain-evoked ACC activity was larger during the distraction condition than during the attend condition. Recent regional cerebral blood flow studies have also reported a distraction-related increase in pain-evoked ACC activity. Our results confirm these reports, and verify that the distraction effect specifically involves pain-evoked ACC activity. The cognitive demands of the distraction task present the possibility that the pain-evoked ACC activity might be involved, at least in part, in response competition and/or orienting attention toward painful stimuli. [source] Attitudes to evidence-based practice in urology: Results of a surveyANZ JOURNAL OF SURGERY, Issue 5 2001Alan M. F. Stapleton Background: The advantages of promoting evidence-based care through implementation of clinical guidelines are well established. Clinical practice guidelines have been developed for lower urinary tract symptoms (LUTS) and prostate cancer screening. Aspects of the delivery of care by urologists or specialist registrars relevant to the guidelines were assessed. Methods: A questionnaire was distributed at the 1999 meeting of the Urological Society of Australasia, which was attended by 187 Australasian and 33 foreign delegates. Questions addressed access to resources for evidence-based medicine; perceived need; preferred sources of information; and then presented four clinical scenarios. These were: (i) treatment recommendations in early stage prostate cancer; (ii) the same scenario if the respondent was the patient; (iii) treatment recommendations after radical prostatectomy when there was a positive resection margin; and (iv) clinical investigations for mild to moderate LUTS. Results: Of 220 possible responses, 132 were received, a response rate of 60%. Urologists overwhelmingly (100%) endorsed the need for access to evidence-based reviews, although 28% claimed such access was non-existent to poor. Clinical guidelines were the preferred source of evidence-based information. For early stage prostate cancer in a 55-year-old man, radical prostatectomy was recommended by 93.2% of respondents, but this dropped to 83% when the respondent was the patient (P < 0.05), and a wider range of treatments was recommended. Pelvic radiotherapy and hormone therapy were equally recommended for biochemical progression following radical prostatectomy where there was a positive surgical margin. Investigations for LUTS included serum prostate-specific antigen (PSA) testing (78.0%) and voided flow studies (77.3%). Conclusions: Urologists express a need for evidence-based practice resources, in particular clinical guidelines. Nevertheless their clinical approach is not necessarily consistent with existing guidelines, particularly for LUTS. An alteration in the recommendation when the respondent is the patient of interest and endorses the recommendation that patients with prostate cancer should be involved in treatment decisions. [source] Endoluminal Norepinephrine Inhibits Smooth Muscle Activity of the Pig Pyeloureter by Stimulation of ,-Adrenoceptors without Side EffectsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2008Jens Mortensen The purposes were to describe concentration,response relationship and receptor mechanism of the effect of norepinephrine on muscle function of pyeloureter and to reveal possible side effects on cardiovascular and renal functions. Renal pelvis was perfused, while pelvic pressure, cardiovascular and renal functional parameters were recorded. In group A, a pelvic pressure increase was examined during pressure flow studies with norepinephrine solutions (0, 1, 5, 50 and 100 µg/ml). In group B, pelvis was perfused with 6 ml/min. norepinephrine solutions (0, 0.001, 0.01, 0.1 and 1 µg/ml). In group C, pelvis was perfused with 6 ml/min. norepinephrine, norepinephrine + sotalol 10,6 mol/l and norepinephrine + phentolamine 10,6 mol/l. Norepinephrine solutions of 0, 10,8, 10,7, 10,6, 10,5 and 10,4 mol/l were used. In group A, all norepinephrine solutions lowered the pelvic pressure increase significantly. Large increases in plasma and urine norepinephrine occurred with 50 and 100 µg/ml, but cardiovascular and renal functions remained unchanged. In group B, a significant diminishing pelvic pressure increase with all solutions was seen with a significant difference between all solutions. In group C, norepinephrine demonstrated a concentration,response curve with EC50 between 10,8 and 10,7 mol/l (10,7.27±0.40). Sotalol had a smooth muscle inhibitory effect on the pyeloureter and inhibited the effect of norepinephrine increasing EC50 by about a factor 10 (10,6.40±1.17). No convincing effect of phentolamine was observed. Endoluminal norepinephrine probably stimulates ,-adrenoceptors and inhibits a renal pelvis pressure increase to perfusion in a dose-related way without side effects. Endoluminal norepinephrine is safe in pigs and may be useful under endoscopy of the pyeloureter. [source] Are conventional pressure-flow measurements dependent upon filled volume?BJU INTERNATIONAL, Issue 3 2005Kanagasabai Sahadevan OBJECTIVE To determine, in a prospective study, whether detrusor pressure (pdet.Qmax) and maximum urinary flow rate (Qmax) measurements obtained after filling to maximum cystometric capacity (MCC) differ from those obtained with filling restricted to average voided volume (Vvoid), as standard protocols for pressure flow studies (PFS) mandate bladder filling until the subject has a strong desire to void, which aids standardization but further divorces the test from real-life experience. PATIENTS AND METHODS After calculating the appropriate sample size, 84 patients attending for PFS with an adequately completed 3-day frequency-volume chart were recruited. Each underwent two consecutive PFS with filling to MCC and average Vvoid in a random order, and measurements of pdet.Qmax and Qmax were compared. For men, the agreement for a diagnosis of obstruction between the tests was also assessed. RESULTS Complete data were obtained from 76 (90%) of the patients, with a mean (range) age of 64 (20,94) years. The mean (sd) difference between MCC and average Vvoid was 134 (113) mL (P < 0.01). There were no significant differences between estimates of Qmax, at ,,0.1 (3) mL/s (P = 0.75), and of pdet.Qmax, at ,,1 (13) cmH2O (P = 0.91), obtained within each patient. For men there was 91% agreement (32 of 35) in the classification of obstruction. CONCLUSIONS Restriction of filling to the average Vvoid during PFS allows a closer approximation to normal voiding and results in no clinically relevant change to the value of standard pressure-flow measurements or alters individual classification of obstruction. [source] Urodynamic effects of silodosin, a new ,1A -adrenoceptor selective antagonist, for the treatment of benign prostatic hyperplasia,,NEUROUROLOGY AND URODYNAMICS, Issue 4 2010Tomonori Yamanishi Abstract Aims To investigate urodynamically the effects of silodosin, a new ,1A -adrenoceptor-selective antagonist, in the treatment of benign prostatic hyperplasia (BPH). Methods Thirty six male patients with BPH (69.9,±,7.3 years), who were referred as candidates for surgery, were treated with silodosin (4,mg twice daily). The total International Prostate Symptom Score (IPSS) was 20.7,±,7.4, maximum flow rate (Qmax) was 6.7,±,3.0,ml/sec, and prostate volume was 45.6,±,24.5,ml. Results Total IPSS, storage and voiding symptom subscores and QOL score decreased significantly, and Qmax increased significantly after 1,12 months of therapy (all P,<,0.05). In urodynamic study (n,=,29), maximum cystometric capacity increased significantly (P,=,0.0027), and detrusor overactivity disappeared in 8 of 20 patients (40%) and improved (bladder capacity increased more than 50%) in 7 (35%) after the therapy. In pressure/flow studies (n,=,27), the obstruction grade was improved in 15 patients (56%). Detrusor opening pressure, detrusor pressure at Qmax, bladder outlet obstruction index, and Schäfer's obstruction class decreased significantly after therapy (all P,<,0.01). After 12 months, 16 patients (44%) are still on silodosin for 23.3,±,7.0 (range 12,36) months, and the improvements in IPSS and Qmax were stable. Twenty patients withdrew because of insufficient effectiveness in 13 patients (12 patients underwent surgery), side effects in 3, and unknown reasons in 4. Conclusion Silodosin appears to improve detrusor overactivity and obstruction grade in patients with BPH. With silodosin treatment, LUTS could be managed effectively for more than a year in at least 44% of the patients. Neurourol. Urodynam. 29:558,562, 2010. © 2009 Wiley-Liss, Inc. [source] | |||||||||||||