Selective Approach (selective + approach)

Distribution by Scientific Domains
Distribution within Medical Sciences

Selected Abstracts

Is Transesophageal Echocardiography Necessary before D.C. Cardioversion in Patients with a Normal Transthoracic Echocardiogram?

Mohsen Sharifi M.D.
Purpose: Transesophageal echocardiography has emerged as an accepted approach before D.C. cardioversion for atrial fibrillation. The frequency of atrial thrombi detected on transesophageal echocardiography has varied from 7% to 23%. Many patients undergoing transesophageal echocardiography have had a previous transthoracic echocardiogram. Though transthoracic echocardiography has a low yield for the detection of intracardiac thrombi, it is highly accurate in diagnosing a structurally abnormal heart. The purpose of this study was to assess the frequency of thrombi detected by transesophageal echocardiography in patients with an entirely normal transthoracic echocardiogram and hence the advocacy of a selective approach in performing transesophageal echocardiography in patients undergoing D.C. cardioversion for atrial fibrillation. Methods: 112 consecutive patients with atrial fibrillation who had undergone transesophageal echocardiography before D.C. cardioversion were evaluated. They all had a transthoracic echocardiogram within the 2 months preceding their transesophageal echocardiogram. Based on their transthoracic echocardiographic study, they were divided into two groups: Group 1 consisted of patients with a normal transthoracic echocardiogram and Group 2, those with an abnormal study. Results: Thrombi or spontaneous echo contrast were found in 14 of 112 patients (16%). All however were detected in Group 2 patients. There was no patient with a normal transthoracic echocardiogram who had thrombus on his/her transesophageal echocardiogram. Conclusions: Our results suggest that a selective approach may be exercised in the use of transesophageal echocardiography prior to D.C. cardioversion for atrial fibrillation. Patients with an entirely "normal" transthoracic echocardiogram may proceed directly to cardioversion without a precardioversion transesophageal echocardiogram. [source]

Magnetic Resonance Sounding: New Method for Ground Water Assessment

GROUND WATER, Issue 2 2004
M. Lubczynski
The advantage of magnetic resonance sounding (MRS) as compared to other classical geophysical methods is in its water selective approach and reduced ambiguity in determination of subsurface free water content and hydraulic properties of the media due to the nuclear magnetic resonance (NMR) principle applied. Two case examples are used to explain how hydrogeological parameters are obtained from an MRS survey. The first case example in Delft (the Netherlands) is a multiaquifer system characterized by large signal to noise ratio (S/N = 73), with a 24 m thick, shallow sand aquifer, confined by a 15 m thick clay layer. For the shallow aquifer, a very good match between MRS and borehole data was obtained with regard to effective porosity nc,28% and specific drainage Sd,20%. The MRS interpretation at the level deeper than 39 m was disturbed by signal attenuation in the low resistivity (,10 ,m) media. The second case of Serowe (Botswana) shows a fractured sandstone aquifer where hydrogeological parameters are well defined at depth >74 m below ground surface despite quite a low S/N = 0.9 ratio, thanks to the negligible signal attenuation in the resistive environment. Finally, capabilities and limitations of the MRS technology are reviewed and discussed. MRS can contribute to subsurface hydrostratigraphy description, hydrogeological system parameterization, and improvement of well siting. The main limitations are survey dependence upon the value of the S/N ratio, signal attenuation in electrically conductive environments, nonuniformity of magnetic field, and some instrumental limitations. At locations sufficiently resistive to disregard the signal attenuation problems, the MRS S/N ratio determines how successfully MRS data can be acquired. Both signal and noise vary spatially; therefore, world scale maps providing guidelines on spatial variability of signal and noise are presented and their importance with respect to the MRS survey results is discussed. The noise varies also temporally; therefore, its diurnal and seasonal variability impact upon the MRS survey is covered as well. [source]

Observations on the Nature and Culture of Environmental History

J. R. McNeill
This article aims to consider the robust field of environmental history as a whole, as it stands and as it has developed over the past twenty-five years around the world. It necessarily adopts a selective approach but still offers more breadth than depth. It treats the links between environmental history and other fields within history, and with other related disciplines such as geography. It considers the precursors of environmental history, its emergence since the 1970s, its condition in several settings and historiographies. Finally it touches on environmental history's relationship to social theory and to the natural sciences as they have evolved in recent decades. It concludes that while there remains plenty of interesting work yet to do, environmental history has successfully established itself as a legitimate field within the historical profession, and has a bright future, if perhaps for discouraging reasons. [source]

An efficient and highly selective method for the synthesis of cryptotackiene derivatives catalyzed by iodine

Xiang-Shan Wang
A mild, efficient and highly selective approach to the synthesis of cryptotackiene derivatives via three-component reactions of 3-amino-9-ethylcarbazole and aromatic aldehydes with electron-rich alkenes, such as 2,3-dihydrofuran, or 3,4-dihydro-2H -pyran catalyzed by iodine in THF is reported. It is worth to note that only trans -products were obtained with high selectivity in good to high yields, which confirmed by X-ray diffraction analysis. J. Heterocyclic Chem., (2010). [source]

The dominantly inherited motor and sensory neuropathies: Clinical and molecular advances

MUSCLE AND NERVE, Issue 5 2006
Garth A. Nicholson MB
Abstract The rapid advances in the molecular genetics and cell biology of hereditary neuropathy have revealed great genetic complexity. It is a challenge for physicians and laboratories to keep pace with new discoveries. Classification of hereditary neuropathies has evolved from a simple clinical to a detailed molecular classification. However, the molecular classification is not simple to use, as different mutations of the same gene produce a range of phenotypes. The logistics of testing for multiple gene mutations are considerable. This review gives a clinical overview of molecular and clinical advances in the dominant hereditary motor and sensory neuropathies [HMSNs, Charcot,Marie,Tooth (CMT) neuropathy], which account for some 60%,70% of families with CMT. The dominant forms of CMT have cellular mechanisms different from those of recessive forms and are a separate diagnostic challenge, so they are not included in this review. Diagnostic testing requires accurate clinical information and a selective approach to gene screening until the cost of multiple gene mutation screening falls. Accurate molecular diagnosis is critical to genetic counseling. This review concentrates on how molecular information can be used clinically, on how physicians can keep pace with new developments, and on the relevance of this new knowledge to patients. Muscle Nerve, 2006 [source]

An integrated strategy for identification and relative quantification of site-specific protein phosphorylation using liquid chromatography coupled to MS2/MS3

Florian Wolschin
Reversible and differential multisite protein phosphorylation is an important mechanism controlling the activity of cellular proteins. Here we describe a robust and highly selective approach for the identification and relative quantification of site-specific phosphorylation events. This integrated strategy has three major parts: visualisation of phosphorylated proteins using fluorescently stained polyacrylamide gels, determination of the phosphorylation site(s) using automatic MS3 triggered by the loss of phosphoric acid, and relative quantification of phosphorylation by integrating MS2 - and MS3 -extracted ion traces using a fast-scanning, linear ion trap mass spectrometer. As a test case, recombinant sucrose-phosphate synthase (SPS) from Arabidopsis thaliana (At5g1110) was used for identification and quantification of site-specific phosphorylation. The identified phosphorylation site of the actively expressed protein coincides with the major regulatory in vivo phosphorylation site in spinach SPS. Site-specific differential in vitro phosphorylation of native protein was demonstrated after incubation of the recombinant protein with cold-adapted plant leaf extracts from A. thaliana, suggesting regulatory phosphorylation events of this key enzyme under stress response. Copyright 2005 John Wiley & Sons, Ltd. [source]

Need for staging laparoscopy in patients with gastric cancer

R. Bhalla
Aims: The aim of preoperative staging in gastric cancer is to correctly identify patients with advanced disease who should not be subjected to surgery and to allow the treatment of those who are admitted for operation to be planned accurately. This study assessed the impact of a policy of selective staging laparoscopy in patients deemed suitable for curative or palliative surgery, to ascertain whether the selective approach increased the frequency of abandoned or unplanned surgical procedures. Methods: Fifty consecutive patients with gastric or type III gastro-oesophageal junction cancer staged by computed tomography (CT) alone, in whom surgery was felt to be appropriate for ,cure' or palliative symptom control, were studied. Specific CT, endoscopic and biochemical criteria were applied prospectively to select out a subgroup of 18 patients who also underwent preoperative staging laparoscopy. The overall accuracy of staging and operative outcomes were assessed. Results: Using this selective approach the resection rate was 98 per cent, although three patients in each group had their planned procedure altered to a less radical (two in each group) or more radical (one in each group) resection (P = 023). Overall, 41 of 50 patients were staged correctly (accuracy 82 (95 per cent confidence interval 69,90) per cent) and 86 per cent of patients underwent the planned surgical procedure. The only abandoned operation occurred in the staging laparoscopy group. Conclusions: It is possible to plan a patient's operation accurately without the need for a staging laparoscopy in all cases. 2000 British Journal of Surgery Society Ltd [source]

Does the need to self-digitate or the presence of a large or nonemptying rectocoele on proctography influence the outcome of transanal rectocoele repair?

S. G. Stojkovic
Abstract Introduction Transanal repair of anterior rectocoele is a well described technique with variable success rate. In our department we offer repair to patients who fit the following criteria; the need to self digitate (transvaginal or perineal); a large rectocoele; a nonemptying rectocoele. Using these selection criteria previous authors have shown excellent results. The aim of our study was to review our results using this selective approach and also to determine whether the need to self digitate, the presence of a large rectocoele and the degree of emptying could predict which patients would achieve a successful result. Methods Fifty-five patients underwent repair over a three-year period. The main presenting symptom was noted for each patient and also whether self-digitation was required in order to achieve successful evacuation. Dynamic evacuation proctography was performed on all patients. Size of rectocoele, percentage of paste expelled and other proctographic abnormalities were noted for each patient. Follow up was at 6 weeks and 6 months at which point patients were asked whether their symptoms had resolved, improved, remained the same or had worsened. Results Complete data were available for 48 of the patients (median age 52 years, IQR 43,63). The presenting complaint was constipation in 22 patients, obstructive defeacation in 15, incomplete evacuation in 5, postdefaecation soiling in 4 and dyspareunia in 2. Thirty-eight patients noted the need to self-digitate, 10 did not. Proctography revealed a large rectocoele (> 4 cm) in 22 patients and a medium or small rectocoele (< 4 cm) in 26 patients. There was a rectocoele alone in 34 patients, in combination with perineal descent in 11 and with intussusception in 3. Median percentage of paste expelled was 70% (range 20,95). At 6 weeks postoperatively, 43 patients had complete resolution of their symptoms whilst 5 reported only some or no improvement. At 6 months, 37 patients sustained complete resolution of their symptoms and 11 did not. Pre-operative factors were compared for these two groups of patients. There was no difference in age (P > 0.05, Mann,Whitney U -test) between the two groups There was also no difference in size of rectocoele, degree of emptying, the presence of another proctographic abnormality and the need to self-digitate between the two groups (P > 0.05, Fisher's exact test). Discussion No factors were seen to distinguish between the successful and unsuccessful groups of patients following rectocoele repair, however, an overall success rate of 75% was achieved using our selection criteria. This figure is in keeping with reported success rates in the literature. [source]

Differential effects of temporal pole resection with amygdalohippocampectomy versus selective amygdalohippocampectomy on material-specific memory in patients with mesial temporal lobe epilepsy

EPILEPSIA, Issue 1 2008
Christoph Helmstaedter
Summary Purpose: In the surgical treatment of mesial temporal lobe epilepsy, there is converging evidence that individually tailored or selective approaches have a favorable cognitive outcome compared to standard resections. There is, however, also evidence that due to collateral damage, selective surgery can be less selective than suggested. As part of a prospective transregional research project the present study evaluated the outcome in memory and nonmemory functions, following two selective approaches: a combined temporal pole resection with amygdalohippocampectomy (TPR+) and transsylvian selective amygdalohippocampectomy (SAH). Methods: One year after surgery, cognitive outcomes of postoperatively seizure-free patients with mesial TLE and hippocampal sclerosis, who underwent either TPR+ (N = 35) or SAH (N = 62) in two German epilepsy centers (Bonn/Berlin), were compared. Results: Repeated measurement MANOVA and separate post hoc testing indicated a double dissociation of verbal/figural memory outcome as dependent on side and type of surgery. Verbal memory outcome was worse after left-sided operation, but especially for SAH, whereas figural memory outcome was worse after right-sided operation, preferentially for TPR+. Attention improved independent of side or type of surgery, and language functions showed some improvement after right-sided surgeries. Discussion: The results indicate a differential effect of left/right SAH versus TPR+ on material-specific memory insofar as transsylvian SAH appears to be favorable in right and TPR+ in left MTLE. The different outcomes are discussed in terms of a different surgical affection of the temporal pole and stem, and different roles of these structures for verbal and figural memory. [source]