409 resultados para internal pressure


Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this study, we assessed whether the white-coat effect (difference between office and daytime blood pressure (BP)) is associated with nondipping (absence of BP decrease at night). Data were available in 371 individuals of African descent from 74 families selected from a population-based hypertension register in the Seychelles Islands and in 295 Caucasian individuals randomly selected from a population-based study in Switzerland. We used standard multiple linear regression in the Swiss data and generalized estimating equations to account for familial correlations in the Seychelles data. The prevalence of systolic and diastolic nondipping (<10% nocturnal BP decrease) and white-coat hypertension (WCH) was respectively 51, 46, and 4% in blacks and 33, 37, and 7% in whites. When white coat effect and nocturnal dipping were taken as continuous variables (mm Hg), systolic (SBP) and diastolic BP (DBP) dipping were associated inversely and independently with white-coat effect (P < 0.05) in both populations. Analogously, the difference between office and daytime heart rate was inversely associated with the difference between daytime and night-time heart rate in the two populations. These results did not change after adjustment for potential confounders. The white-coat effect is associated with BP nondipping. The similar associations between office-daytime values and daytime-night-time values for both BP and heart rate suggest that the sympathetic nervous system might play a role. Our findings also further stress the interest, for clinicians, of assessing the presence of a white-coat effect as a means to further identify patients at increased cardiovascular risk and guide treatment accordingly.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Despite two international studies, there is still no consensus concerning prostate cancer screening. The results of a meta-analysis are making us question our convictions concerning pneumococcal vaccination. The preoperative work-up of cataract surgery can be simplified. When describing the efficacy of a treatment to a patient, relative risks are better understood than absolute risks. For rotator cuff syndrome, intramuscular corticosteroid injections are as efficient as intra-articular injections. In patients prescribed clopidogrel, a proton pump inhibitor is not absolutely necessary. The arrival of a anticoagulant that does not need blood monitoring is an interesting option in atrial fibrillation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Acquired pressure ulcer is associated with significant human, economic and functional consequences. Its prevalence varies between 3 and 23% in a community hospital and between 7 and 54% in an elderly home residency. Pressure ulcer healing is a complex process which involves numerous cellular and molecular mechanisms. An altered nutritional status is a contributing factor in the development of pressure ulcers and the delay in pressure ulcer healing. The key to management of undernutrition is screening and early intervention. According to the gravity of undernutrition, various degrees of intervention will be required. Systematic oral supplementation with various nutrients may provide benefit in the prevention of pressure ulcers, but further studies have to be completed in human subjects prior to being recommended for the treatment of pressure ulcers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVE: Blood pressure (BP) measured in obese patients with a large arm circumference using a cuff of standard width may be overestimated. METHODS: We compared in this study the BP readings obtained with oscillometric devices at the left arm (OMRON HEM 705-CP) and the left wrist (OMRON R6) (Omron Medizintechnik, Mannheim, Germany) in lean (n=15) and obese (n=11) patients. RESULTS: No difference was found in diastolic BP between the two groups, nor between the arm and the wrist. Systolic BP measured at the arm was, however, significantly lower in obese (99+/-9 mmHg, mean+/-SD) than in lean (107+/-14 mmHg; P<0.001) patients, whereas systolic BP determined at the wrist averaged 106 mmHg in both groups. CONCLUSION: The use of validated wrist BP measuring devices appears therefore particularly appealing in obese individuals with a large arm circumference

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A novel laboratory technique is proposed to investigate wave-induced fluid flow on the mesoscopic scale as a mechanism for seismic attenuation in partially saturated rocks. This technique combines measurements of seismic attenuation in the frequency range from 1 to 100?Hz with measurements of transient fluid pressure as a response of a step stress applied on top of the sample. We used a Berea sandstone sample partially saturated with water. The laboratory results suggest that wave-induced fluid flow on the mesoscopic scale is dominant in partially saturated samples. A 3-D numerical model representing the sample was used to verify the experimental results. Biot's equations of consolidation were solved with the finite-element method. Wave-induced fluid flow on the mesoscopic scale was the only attenuation mechanism accounted for in the numerical solution. The numerically calculated transient fluid pressure reproduced the laboratory data. Moreover, the numerically calculated attenuation, superposed to the frequency-independent matrix anelasticity, reproduced the attenuation measured in the laboratory in the partially saturated sample. This experimental?numerical fit demonstrates that wave-induced fluid flow on the mesoscopic scale and matrix anelasticity are the dominant mechanisms for seismic attenuation in partially saturated Berea sandstone.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Invasive studies suggest that healthy children living at high altitude display pulmonary hypertension, but the data to support this assumption are sparse. Nitric oxide (NO) synthesized by the respiratory epithelium regulates pulmonary artery pressure, and its synthesis was reported to be increased in Aymara high-altitude dwellers. We hypothesized that pulmonary artery pressure will be lower in Aymara children than in children of European ancestry at high altitude, and that this will be related to increased respiratory NO. We therefore compared pulmonary artery pressure and exhaled NO (a marker of respiratory epithelial NO synthesis) between large groups of healthy children of Aymara (n = 200; mean +/- SD age, 9.5 +/- 3.6 years) and European ancestry (n = 77) living at high altitude (3,600 to 4,000 m). We also studied a group of European children (n = 29) living at low altitude. The systolic right ventricular to right atrial pressure gradient in the Aymara children was normal, even though significantly higher than the gradient measured in European children at low altitude (22.5 +/- 6.1 mm Hg vs 17.7 +/- 3.1 mm Hg, p < 0.001). In children of European ancestry studied at high altitude, the pressure gradient was 33% higher than in the Aymara children (30.0 +/- 5.3 mm Hg vs 22.5 +/- 6.1 mm Hg, p < 0.0001). In contrast to what was expected, exhaled NO tended to be lower in Aymara children than in European children living at the same altitude (12.4 +/- 8.8 parts per billion [ppb] vs 16.1 +/- 11.1 ppb, p = 0.06) and was not related to pulmonary artery pressure in either group. Aymara children are protected from hypoxic pulmonary hypertension at high altitude. This protection does not appear to be related to increased respiratory NO synthesis.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aim: When planning SIRT using 90Y microspheres, the partition model is used to refine the activity calculated by the body surface area (BSA) method to potentially improve the safety and efficacy of treatment. For this partition model dosimetry, accurate determination of mean tumor-to-normal liver ratio (TNR) is critical since it directly impacts absorbed dose estimates. This work aimed at developing and assessing a reliable methodology for the calculation of 99mTc-MAA SPECT/CT-derived TNR ratios based on phantom studies. Materials and methods: IQ NEMA (6 hot spheres) and Kyoto liver phantoms with different hot/background activity concentration ratios were imaged on a SPECT/CT (GE Infinia Hawkeye 4). For each reconstruction with the IQ phantom, TNR quantification was assessed in terms of relative recovery coefficients (RC) and image noise was evaluated in terms of coefficient of variation (COV) in the filled background. RCs were compared using OSEM with Hann, Butterworth and Gaussian filters, as well as FBP reconstruction algorithms. Regarding OSEM, RCs were assessed by varying different parameters independently, such as the number of iterations (i) and subsets (s) and the cut-off frequency of the filter (fc). The influence of the attenuation and diffusion corrections was also investigated. Furthermore, both 2D-ROIs and 3D-VOIs contouring were compared. For this purpose, dedicated Matlab© routines were developed in-house for automatic 2D-ROI/3D-VOI determination to reduce intra-user and intra-slice variability. Best reconstruction parameters and RCs obtained with the IQ phantom were used to recover corrected TNR in case of the Kyoto phantom for arbitrary hot-lesion size. In addition, we computed TNR volume histograms to better assess uptake heterogeneityResults: The highest RCs were obtained with OSEM (i=2, s=10) coupled with the Butterworth filter (fc=0.8). Indeed, we observed a global 20% RC improvement over other OSEM settings and a 50% increase as compared to the best FBP reconstruction. In any case, both attenuation and diffusion corrections must be applied, thus improving RC while preserving good image noise (COV<10%). Both 2D-ROI and 3D-VOI analysis lead to similar results. Nevertheless, we recommend using 3D-VOI since tumor uptake regions are intrinsically 3D. RC-corrected TNR values lie within 17% around the true value, substantially improving the evaluation of small volume (<15 mL) regions. Conclusions: This study reports the multi-parameter optimization of 99mTc MAA SPECT/CT images reconstruction in planning 90Y dosimetry for SIRT. In phantoms, accurate quantification of TNR was obtained using OSEM coupled with Butterworth and RC correction.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Phengites from the eclogite and blueschist-facies sequences of the Cycladic island of Syros (Greece) have been dated by the in situ UV-laser ablation Ar-40/Ar-39 method. A massive, phengite-rich eclogite and an omphacite-rich metagabbro were investigated. The phengites are eubedral and coarse-grained (several 100 mum), strain-free and exhibit no evidence for late brittle deformation or recrystallization. Apparent ages in these samples range from 43 to 50 Ma for the phengite-rich eclogite and 42 to 52 Ma for the ompbacitic metagabbro. This large spread of ages is visible at all scales-within individual grains as well as in domains of several 100 mum and across the entire sample (ca. 2 cm). Such variations have been traditionally attributed to metamorphic cooling or the incorporation of excess argon. However, the textural equilibrium between the phengites and other high pressure phases and the subtle compositional variations within the phengites, especially the preservation of growth textures, alternatively suggest that the observed range in ages may reflect variations of radiogenic argon acquired during phengite formation and subsequent growth, thus dating a discrete event on the prograde path. This implies that the oldest phengite 40Ar/39Ar ages provide the best estimate of a minimum crystallization age, which is in agreement with recently reported U-Pb and Lu-Hf geochronological data. Our results are consistent with available stable isotope data and further suggest that, under fluid-restricted conditions, both stable and radiogenic isotopic systems can survive without significant isotopic exchange during subduction and exhumation from eclogite-facies P-T conditions. (C) 2004 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

From our reading over the current year 2010 we have singled out 8 items which seem to us significant for the practice of medicine. Small doses of colchicine are useful in the treatment of gout. No efficacious treatment for muscular cramps can be recommended. A cervical collar can be usefully prescribed for the treatment of cervical radiculopathy. A single dose of azithromycin can be envisaged as a third line treatment of syphilis. High doses of vitamin D should not be prescribed for the prevention of fractures in elderly women because of the risks of falling. The wearing of bifocals can be associated with these risks. A clinical score is available to help with the diagnosis of thoracic pain. The NT-pro BNP is of limited use for the follow-up of patients suffering from heart failure.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Internists must regularly adjust their patients care according to recent relevant publications. The chief residents from the Department of Internal Medicine of a university hospital present some major themes of internal medicine treated during the year 2009. Emphasis will be placed primarily on changes in the daily hospital practice induced by these recent studies. This variety of topics illustrates both the broad spectrum of the current internal medicine, and the many uncertainties associated with modern medical practice based on evidence.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

INTRODUCTION: Auscultatory nonmercury manual devices seem good alternatives for the mercury sphygmomanometers in the clinic and for research settings, but individual internal validation of each device is time-consuming. The aim of this study was to validate a new technique capable of testing two devices simultaneously, based on the International protocol of the European Society of Hypertension. METHODS: The concept of the new technique is to measure blood pressure alternatively by two observers using a mercury sphygmomanometer and by two observers using the A&D UM-101 and Accoson Greenlight 300 devices, connected by Y-tube to obtain simultaneous readings with both nonmercury devices. Thirty-three participants were enrolled (mean age 47.2±14.0 years). Nine sequential blood pressure measurements were performed for each participant. RESULTS: Both devices passed phase 1 using 15 participants. In phase 2.1 (n=33), on a maximum of 99 measurements, the Accoson device produced 81/95/99 measurements within 5/10/15 mmHg for systolic blood pressure (SBP) and 87/98/99 for diastolic blood pressure (DBP). The A&D device produced 86/96/99 for SBP and 94/99/99 for DBP. In phase 2.2 (n=33), 30 participants had at least 2 out of 3 SBP obtained with Accoson device within 5 mmHg of the mercury device, as compared with 29 of 33 participants with the A&D device. For DBP, this was 33 of 33 participants for both devices. CONCLUSION: Both the nonmercury devices passed the International protocol. The new technique of simultaneous device testing using a Y-tube represents a time saving application of the International protocol.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A HPLC method is presented for the identification and quantification in plasma and urine of beta-adrenergic receptor antagonists (betaxolol, carteolol, metipranolol, and timolol) commonly prescribed in ophthalmology. An extraction method is described using pindolol as an internal standard. An RSIL 10 micron column was used. The lower detection limits of the beta-blockers were found to be 4-27 ng/ml. This method is simple, rapid and sensitive; moreover, it allows the determination of 8 other beta-blockers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

PURPOSE: To describe the clinical and histologic features of a particular form of macular epiretinal membrane. METHODS: The charts of all patients operated for macular epiretinal membrane by a single surgeon (E.H.B.) between June 2001 and January 2005 were retrospectively reviewed. Patients with macular epiretinal membrane associated with tearing and folding of the internal limiting membrane (ILM) were identified and the following parameters were recorded when available: age, gender, best-corrected visual acuity before and after vitrectomy; optical coherence tomography; pre-, intra-, and postoperative macular status; intraoperative staining by indocyanine green; histology. RESULTS: Twenty-three of 268 eyes (8.6%) with macular epiretinal membrane were associated with tearing and folding of the ILM, forming a whitish prominent band on the surface of the retina. The mean age of the patients was 68.6 years with a significant female predominance (78.3%). The vitreous was completely detached in 21 eyes. After surgical peeling, the mean visual gain was 3.2 Early Treatment Diabetic Retinopathy Study lines. No recurrence was observed. CONCLUSION: Tearing and folding of the ILM was associated with macular epiretinal membranes in 8.6% of cases. The ILM was probably torn during posterior hyaloid detachment, but the pathogenesis has not been clearly elucidated. The surgeon should begin to peel the macular epiretinal membrane by grasping the folded ILM to ensure complete removal of the ILM together with the epiretinal membrane. The postoperative visual prognosis was good