74 resultados para large volume samples

em Université de Lausanne, Switzerland


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Solid-phase extraction (SPE) in tandem with dispersive liquid-liquid microextraction (DLLME) has been developed for the determination of mononitrotoluenes (MNTs) in several aquatic samples using gas chromatography-flame ionization (GC-FID) detection system. In the hyphenated SPE-DLLME, initially MNTs were extracted from a large volume of aqueous samples (100 mL) into a 500-mg octadecyl silane (C(18) ) sorbent. After the elution of analytes from the sorbent with acetonitrile, the obtained solution was put under the DLLME procedure, so that the extra preconcentration factors could be achieved. The parameters influencing the extraction efficiency such as breakthrough volume, type and volume of the elution solvent (disperser solvent) and extracting solvent, as well as the salt addition, were studied and optimized. The calibration curves were linear in the range of 0.5-500 μg/L and the limit of detection for all analytes was found to be 0.2 μg/L. The relative standard deviations (for 0.75 μg/L of MNTs) without internal standard varied from 2.0 to 6.4% (n=5). The relative recoveries of the well, river and sea water samples, spiked at the concentration level of 0.75 μg/L of the analytes, were in the range of 85-118%.

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High throughput genome (HTG) and expressed sequence tag (EST) sequences are currently the most abundant nucleotide sequence classes in the public database. The large volume, high degree of fragmentation and lack of gene structure annotations prevent efficient and effective searches of HTG and EST data for protein sequence homologies by standard search methods. Here, we briefly describe three newly developed resources that should make discovery of interesting genes in these sequence classes easier in the future, especially to biologists not having access to a powerful local bioinformatics environment. trEST and trGEN are regularly regenerated databases of hypothetical protein sequences predicted from EST and HTG sequences, respectively. Hits is a web-based data retrieval and analysis system providing access to precomputed matches between protein sequences (including sequences from trEST and trGEN) and patterns and profiles from Prosite and Pfam. The three resources can be accessed via the Hits home page (http://hits. isb-sib.ch).

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Tumescent anesthesia is a local anesthesia produced by the infiltration of a large volume of very dilute anesthetic solution into the subcutaneous tissue. Many surgical procedures (liposuction, facelift, varicose vein surgery, etc.), which were previously performed under general or locoregional anesthesia, can now be achieved with local tumescent anesthesia. This type of anesthesia has many advantages: reduction of both anesthetic risks and surgical complications (bleeding, hematoma), prolonged anesthesia reducing the need for postoperative analgesia, and costs reduction because all these surgical procedures can be performed on an outpatient basis.

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The respective roles of the medial temporal lobe (MTL) structures in memory are controversial. Some authors put forward a modular account according to which episodic memory and recollection-based processes are crucially dependent on the hippocampal formation whereas semantic acquisition and familiarity-based processes rely on the adjacent parahippocampal gyri. Others defend a unitary view. We report the case of VJ, a boy with developmental amnesia of most likely perinatal onset diagnosed at the age of 8. Magnetic resonance imaging (MRI), including quantitative volumetric measurements of the hippocampal formation and of the entorhinal, perirhinal, and temporopolar cortices, showed severe, bilateral atrophy of the hippocampal formation, fornix and mammillary bodies; by contrast, the perirhinal cortex was within normal range and the entorhinal and temporopolar cortex remained within two standard deviations (SDs) from controls' mean. We examined the development of his semantic knowledge from childhood to teenage as well as his recognition and cued recall memory abilities. On tasks tapping semantic memory, VJ increased his raw scores across years at the same rate as children from large standardisation samples, except for one task; he achieved average performance, consistent with his socio-educational background. He performed within normal range on 74% of recognition tests and achieved average to above average scores on 42% of them despite very severe impairment on 82% of episodic recall tasks. Both faces and landscapes-scenes gave rise to above average scores when tested with coloured stimuli. Cued recall, although impaired, was largely superior to free recall. This case supports a modular account of the MTL with episodic, but not semantic memory depending on the hippocampal formation. Furthermore, the overall pattern of findings is consistent with evidence from both brain-damaged and neuroimaging studies indicating that recollection requires intact hippocampal formation and familiarity relies, at least partly, on the adjacent temporal lobe cortex.

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OBJECTIVES: The goal of the present study was to develop a strategy for three-dimensional (3D) volume acquisition along the major axes of the coronary arteries. BACKGROUND: For high-resolution 3D free-breathing coronary magnetic resonance angiography (MRA), coverage of the coronary artery tree may be limited due to excessive measurement times associated with large volume acquisitions. Planning the 3D volume along the major axis of the coronary vessels may help to overcome such limitations. METHODS: Fifteen healthy adult volunteers and seven patients with X-ray angiographically confirmed coronary artery disease underwent free-breathing navigator-gated and corrected 3D coronary MRA. For an accurate volume targeting of the high resolution scans, a three-point planscan software tool was applied. RESULTS: The average length of contiguously visualized left main and left anterior descending coronary artery was 81.8 +/- 13.9 mm in the healthy volunteers and 76.2 +/- 16.5 mm in the patients (p = NS). For the right coronary artery, a total length of 111.7 +/- 27.7 mm was found in the healthy volunteers and 79.3 +/- 4.6 mm in the patients (p = NS). Comparing coronary MRA and X-ray angiography, a good agreement of anatomy and pathology was found in the patients. CONCLUSIONS: Double-oblique submillimeter free-breathing coronary MRA allows depiction of extensive parts of the native coronary arteries. The results obtained in patients suggest that the method has the potential to be applied in broader prospective multicenter studies where coronary MRA is compared with X-ray angiography.

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Hepatorenal syndrome is a particular form of functional renal failure which may develop in patients with liver cirrhosis. On a clinical standpoint, precise diagnostic criteria have been established to clearly define this entity, whereas recent advances in the understanding of the biology of vasoactive mediators and the physiology of microcirculation have allowed to better anticipate its pathophysiological mechanisms. During the course of cirrhosis, sinusoidal portal hypertension leads to splanchnic and systemic vasodilation, responsible for a reduction of effective arterial blood volume. As a result, a state of intense renal vasoconstriction develops, leading to renal failure in the absence of any organic renal disease. At this stage, liver transplantation is the only definitive therapy able to reverse renal dysfunction. In recent years, innovative therapies have shown promise to prolong survival in patients with hepatorenal syndrome, including the administration of analogs of vasopressin (mainly terlipressin), the insertion of transjugular intrahepatic portosystemic shunts and the use of novel techniques of dialysis. On a preventive viewpoint, several simple measures have been shown to reduce the risk of hepatorenal syndrome in cirrhotic patients, including the appropriate use of diuretics, the avoidance of nephrotoxic drugs, the prophylaxis of spontaneous bacterial peritonitis and optimal fluid management in patients undergoing large volume paracentesis.

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BACKGROUND: Partial excision of the nail matrix (matricectomy) is generally considered necessary in the surgical treatment of ingrown toenail. Recurrences may occur, however, and poor cosmetic results are frequently observed. OBJECTIVE: The objective is to present a new surgical procedure for ingrown toenail with complete preservation of the nail matrix. METHODS: Twenty-three patients with ingrown toenail were included in this study. The surgical excision was performed 1 week after the completion of treatment of the initial infection. A large volume of soft tissue surrounding the nail plate was removed under local anesthesia. No matrix excision was performed. RESULTS: Short-term results were excellent. No recurrences or severe complications were observed during the minimum 12-months follow-up period. Cosmetic results were remarkable. CONCLUSIONS: Ingrown toenail results from the compression of the lateral nail folds on the nail plate. This study shows that ingrown toenail can be surgically treated without matricectomy. A large volume of soft tissue surrounding the nail plate should be removed to decompress the nail and reduce inflammation. Cosmetic results are excellent and superior to the classical Emmert plasty. Postoperative nail dystrophies and spicule formation are not observed. The main advantage of this surgical approach is the complete preservation of the anatomy and function of the nail to improve both therapeutic and cosmetic results.

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Investigation of violent death, especially cases of sharp trauma and gunshot, is an important part of medico-legal investigations. Beside the execution of a conventional autopsy, the performance of a post-mortem Multi-Detector Computed Tomography (MDCT)-scan has become a highly appreciated tool. In order to investigate also the vascular system, post-mortem CT-angiography has been introduced. The most studied and widespread technique is the Multi-phase post-mortem CT-angiography (MPMCTA). Its sensitivity to detect vascular lesions is even superior to conventional autopsy. The application of MPMCTA for cases of gunshot and sharp-trauma is therefore an obvious choice, as vascular lesions are common in such victims. In most cases of sharp trauma and in several cases of gunshots, death can be attributed to exsanguinations. MPMCTA is able to detect the exact source of bleeding and also to visualize trajectories, which are of most importance in these cases. The reconstructed images allow to clearly visualizing the trajectory in a way that is easily comprehensible for not medically trained legal professionals. The sensitivity of MPMCTA for soft tissue and organ lesions approximately matches the sensitivity of conventional autopsy. However, special care, experience and effective use of the imaging software is necessary for performing the reconstructions of the trajectory. Large volume consuming haemorrhages and shift of inner organs are sources of errors and misinterpretations. This presentation shall give an overview about the advantages and limitations of the use of MPMCTA for investigating cases of gunshot and sharp-trauma.

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Chemical mass transfer was quantified in a metacarbonate xenolith enclosed within the granodiorite of the Qu,rigut massif (Pyrenees, France). Mass balance calculations suggest a strong decrease of CaO, SrO and CO(2) contents (up to -90%), correlated with a decrease of modal calcite content as the contact is approached. Most other chemical elements behave immobile during metasomatism. They are therefore passively enriched. Only a small increase of SiO(2), Al(2)O(3) and Fe(2)O(3) contents occurs in the immediate vicinity of the contact. Hence, in this study, skarn formation is characterized by the lack of large chemical element influx from the granitoid protolith. A large decrease of the initial carbonate volume (up to -86%) resulted from a combination of decarbonation reactions and loss of CaO and CO(2). The resulting volume change has potentially important consequences for the interpretation of stable isotope profiles: the isotope alteration could have occured over greater distances than those observed today.

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The high density of slope failures in western Norway is due to the steep relief and to the concentration of various structures that followed protracted ductile and brittle tectonics. On the 72 investigated rock slope instabilities, 13 were developed in soft weathered mafic and phyllitic allochthons. Only the intrinsic weakness of such rocks increases the susceptibility to gravitational deformation. In contrast, the gravitational structures in the hard gneisses reactivate prominent ductile or/and brittle fabrics. At 30 rockslides along cataclinal slopes, weak mafic layers of foliation are reactivated as basal planes. Slope-parallel steep foliation forms back-cracks of unstable columns. Folds are specifically present in the Storfjord area, together with a clustering of potential slope failures. Folding increases the probability of having favourably orientated planes with respect to the gravitational forces and the slope. High water pressure is believed to seasonally build up along the shallow-dipping Caledonian detachments and may contribute to destabilization of the rock slope upwards. Regional cataclastic faults localized the gravitational structures at 45 sites. The volume of the slope instabilities tends to increase with the amount of reactivated prominent structures and the spacing of the latter controls the size of instabilities.

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BACKGROUND: Studies on the association between homocysteine levels and depression have shown conflicting results. To examine the association between serum total homocysteine (tHcy) levels and major depressive disorder (MDD) in a large community sample with an extended age range. METHODS: A total of 3392 men and women aged 35-66 years participating in the CoLaus study and its psychiatric arm (PsyCoLaus) were included in the analyses. High tHcy measured from fasting blood samples was defined as a concentration ≥15μmol/L. MDD was assessed using the semi-structured Diagnostic Interview for Genetics Studies. RESULTS: In multivariate analyses, elevated tHcy levels were associated with greater odds of meeting the diagnostic criteria for lifetime MDD among men (OR=1.71; 95% CI, 1.18-2.50). This was particularly the case for remitted MDD. Among women, there was no significant association between tHcy levels and MDD and the association tended to be in the opposite direction (OR=0.61; 95% CI, 0.34-1.08). CONCLUSIONS: In this large population-based study, elevated tHcy concentrations are associated with lifetime MDD and particularly with remitted MDD among men.

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BACKGROUND: Low 24-hour urine volume (24 UV) may be a significant risk factor for decline in kidney function. We therefore aimed to study associated markers and possible determinants of 24 UV in a sample of the Swiss population. METHODS: The cross-sectional Swiss Salt Study included a population-based sample of 1535 (746 men and 789 women) individuals from three linguistic regions of Switzerland. Data from 1300 subjects were available for the present analysis. 24 UV was measured using 24-hour urine collection. Determinants of 24 UV were identified using multivariable linear regression models. RESULTS: In bivariate analysis, 24 UV was higher in women compared to men (2000 ml/24 h [interquartile range (IQR): 1354, 2562] versus 1780 ml/24 h [IQR: 1244, 2360], p = 0.002). In multivariable regression analyses, independent associated markers of 24 UV were female sex (β = 280, 95% confidence interval [CI]: 174, 386, p < 0.0001), fluid intake (β = 604, 95% CI: 539, 670, p < 0.0001), sodium excretion (β = 4.2, 95% CI: 3.4, 4.9, p < 0.0001) age (β = 6.6, CI: 3.4, 9.7, p < .0001), creatinine clearance (β = 2.4, CI: 0.2, 4.6, p = 0.04), living in the German-speaking part of Switzerland (β = 124, CI: 29, 219, p = 0.01), alcohol consumption (β = 41, CI: 9, 73, p = 0.01 for increasing categories of alcohol consumption), body mass index (β = -32, CI: -45, -18, p < 0.0001), current smoking (β = -146, CI: -265, -26, p = 0.02), and consumption of meat and cold cut (β = -56, CI: -108, -5, p = 0.03). CONCLUSION: In this large population-based, cross-sectional study, we found several strong and independent correlates for 24 UV. These findings may be important to improve our understanding in the development of chronic kidney disease.

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Mitochondrial (M) and lipid droplet (L) volume density (vd) are often used in exercise research. Vd is the volume of muscle occupied by M and L. The means of calculating these percents are accomplished by applying a grid to a 2D image taken with transmission electron microscopy; however, it is not known which grid best predicts these values. PURPOSE: To determine the grid with the least variability of Mvd and Lvd in human skeletal muscle. METHODS: Muscle biopsies were taken from vastus lateralis of 10 healthy adults, trained (N=6) and untrained (N=4). Samples of 5-10mg were fixed in 2.5% glutaraldehyde and embedded in EPON. Longitudinal sections of 60 nm were cut and 20 images were taken at random at 33,000x magnification. Vd was calculated as the number of times M or L touched two intersecting grid lines (called a point) divided by the total number of points using 3 different sizes of grids with squares of 1000x1000nm sides (corresponding to 1µm2), 500x500nm (0.25µm2) and 250x250nm (0.0625µm2). Statistics included coefficient of variation (CV), 1 way-BS ANOVA and spearman correlations. RESULTS: Mean age was 67 ± 4 yo, mean VO2peak 2.29 ± 0.70 L/min and mean BMI 25.1 ± 3.7 kg/m2. Mean Mvd was 6.39% ± 0.71 for the 1000nm squares, 6.01% ± 0.70 for the 500nm and 6.37% ± 0.80 for the 250nm. Lvd was 1.28% ± 0.03 for the 1000nm, 1.41% ± 0.02 for the 500nm and 1.38% ± 0.02 for the 250nm. The mean CV of the three grids was 6.65% ±1.15 for Mvd with no significant differences between grids (P>0.05). Mean CV for Lvd was 13.83% ± 3.51, with a significant difference between the 1000nm squares and the two other grids (P<0.05). The 500nm squares grid showed the least variability between subjects. Mvd showed a positive correlation with VO2peak (r = 0.89, p < 0.05) but not with weight, height, or age. No correlations were found with Lvd. CONCLUSION: Different size grids have different variability in assessing skeletal muscle Mvd and Lvd. The grid size of 500x500nm (240 points) was more reliable than 1000x1000nm (56 points). 250x250nm (1023 points) did not show better reliability compared with the 500x500nm, but was more time consuming. Thus, choosing a grid with square size of 500x500nm seems the best option. This is particularly relevant as most grids used in the literature are either 100 points or 400 points without clear information on their square size.

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PURPOSE: To understand the reasons for differences in the delineation of target volumes between physicians. MATERIAL AND METHODS: 18 Swiss radiooncology centers were invited to delineate volumes for one prostate and one head-and-neck case. In addition, a questionnaire was sent to evaluate the differences in the volume definition (GTV [gross tumor volume], CTV [clinical target volume], PTV [planning target volume]), the various estimated margins, and the nodes at risk. Coherence between drawn and stated margins by centers was calculated. The questionnaire also included a nonspecific series of questions regarding planning methods in each institution. RESULTS: Fairly large differences in the drawn volumes were seen between the centers in both cases and also in the definition of volumes. Correlation between drawn and stated margins was fair in the prostate case and poor in the head-and-neck case. The questionnaire revealed important differences in the planning methods between centers. CONCLUSION: These large differences could be explained by (1) a variable knowledge/interpretation of ICRU definitions, (2) variable interpretations of the potential microscopic extent, (3) difficulties in GTV identification, (4) differences in the concept, and (5) incoherence between theory (i.e., stated margins) and practice (i.e., drawn margins).

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Background: Previous studies reported an increase of mean platelet volume (MPV) in patients with acute ischemic stroke. However, its correlation with stroke severity has not been investigated. Moreover, studies on the association of MPV with functional outcome yielded inconsistent results. Methods: We included all consecutive ischemic stroke patients admitted to CHUV (Centre Hospitalier Universitaire Vaudois) Neurology Service within 24 h after stroke onset who had MPV measured on admission. The association of MPV with stroke severity (NIHSS score at admission and at 24 h) and outcome (Rankin Scale score at 3 and 12 months) was analyzed in univariate analysis. The chi(2) test was performed to compare the frequency of minor strokes (NIHSS score </=4) and good functional outcome (Rankin Scale score </=2) across MPV quartiles. The ANOVA test was used to compare MPV between stroke subtypes according to the TOAST classification. Student's two-tailed unpaired t test was performed to compare MPV between lacunar and nonlacunar strokes. MPV was generated at admission by the Sysmex XE-2100 automated cell counter (Sysmex Corporation, Kobe, Japan) from EDTA blood samples. Results: There was no significant difference in the frequency of minor strokes (p = 0.46) and good functional outcome (p = 0.06) across MPV quartiles. MPV was not associated with stroke severity or outcome in univariate analysis. There was no significant difference in MPV between stroke subtypes according to the TOAST classification (p = 0.173) or between lacunar and nonlacunar strokes (10.50 +/- 0.91 vs. 10.40 +/- 0.81 fl, p = 0.322). Conclusions: MPV, assessed within 24 h after ischemic stroke onset, is not associated with stroke severity or functional outcome.