984 resultados para frequency changes


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Background: The use of springs in cranial expansion has demonstrated to be effective for craniosynostosis treatment. The spring-exerted expansile action has been observed when springs are placed both in the sagittal and parasagittal regions, mainly in scaphocephaly. In this study, a variation in cephalometric measurements under expansible spring action on the skull base was analyzed. Methods: Thirteen 4-week-old New Zealand white rabbits were divided into 4 groups: group 1, in which only amalgam markers were used (control); group 2, in which amalgam markers were used, and a sagittal suturectomy was performed; group 3, in which amalgam markers were used, and a sagittal suturectomy was performed with placement of expansible springs in the interparietal region; and group 4, in which markers were used, and a linear parasagittal craniectomy was performed with spring placement. All animals were killed at weeks 2, 4, 8, and 12. Radiologic control with cephalometric study was performed. Results: Distraction of amalgam markers in the groups with springs was greater than in those without springs. A proportional change in the angles measured through craniometry was observed in these groups. Conclusions: The experimental rabbit model was shown to be adequate to the analysis proposed by the study. Under the action of springs, the groups with sagittal and parasagittal osteotomy were found to present a similar distraction of amalgam markers. A concomitant change in cephalometric measurements occurred, suggesting a change in the skull base mediated by expansible springs placed both in the sutural and nonsutural sites.

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Objective: To illustrate methodological issues involved in estimating dietary trends in populations using data obtained from various sources in Australia in the 1980s and 1990s. Methods: Estimates of absolute and relative change in consumption of selected food items were calculated using national data published annually on the national food supply for 1982-83 to 1992-93 and responses to food frequency questions in two population based risk factor surveys in 1983 and 1994 in the Hunter Region of New South Wales, Australia. The validity of estimated food quantities obtained from these inexpensive sources at the beginning of the period was assessed by comparison with data from a national dietary survey conducted in 1983 using 24 h recall. Results: Trend estimates from the food supply data and risk factor survey data were in good agreement for increases in consumption of fresh fruit, vegetables and breakfast food and decreases in butter, margarine, sugar and alcohol. Estimates for trends in milk, eggs and bread consumption, however, were inconsistent. Conclusions: Both data sources can be used for monitoring progress towards national nutrition goals based on selected food items provided that some limitations are recognized. While data collection methods should be consistent over time they also need to allow for changes in the food supply (for example the introduction of new varieties such as low-fat dairy products). From time to time the trends derived from these inexpensive data sources should be compared with data derived from more detailed and quantitative estimates of dietary intake.

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The effects of 4 estrus synchronization treatments on intervals to and synchrony of estrus and ovulation, on timing of the preovulatory LH surge and associated changes in plasma progesterone, LH, FSH, and 17 beta-estradiol (E(2)) were investigated in 48 Bos indicus cows. Treatment 1 consisted of 2 injections of PGF(2 alpha) 14 d apart (n = 12); Treatment 2 of a subcutaneous 3-mg norgestomet implant and an intramuscular injection of 3 mg of norgestomet and 5 mg estradiol valerate, with the implant removed 10 d later (n = 12; norgestomet-estradiol); Treatment 3 of norgestomet-estradiol, with a subcutaneous injection of PMSG given at time of implant removal (Day 10; n = 12); and Treatment 4 of norgestomet implant (as for Treatments 2 and 3) inserted for 10 d, with an intramuscular injection of PGF(2 alpha) given at the time of implant removal (n = 12). The experiment was conducted in 2 replicates (24 cows/replicate, 6 cows/group). Estrus, ovulation and timing of the preovulatory surge of LH varied less in cows treated with norgestomet-estradiol and PMSG than in cows in Treatments 1 and 4 (P < 0.008). Treatment with PMSG;educed variation in ovulation times and timing of the LH surge in cows treated with norgestomet-estradiol (P < 0.02). Concentrations of E(2) were higher in cows in Treatments 2 and 3 on the final day of treatment and at about 6 h post ovulation compared with cows in Treatments 1 and 4 (P < 0.05). Different methods for synchronizing estrus did not alter sequential endocrine and behavioral changes in relation to the timing of the LH peak, and the results were consistent with current recommendations for insemination times in Bos taurus cattle. (C) 1997 by Elsevier Science Inc.

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The technique of frequency-resolved optical gating is used to characterize the intensity and the phase of picosecond pulses after propagation through 700 m of fiber at close to the zero-dispersion wavelength. Using the frequency-resolved optical gating technique, we directly measure the severe temporal distortion resulting from the interplay between self-phase modulation and higher-order dispersion in this regime. The measured intensity and phase of the pulses after propagation are found to be in good agreement with the predictions of numerical simulations with the nonlinear Schrodinger equation. (C) 1997 Optical Society of America.

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Objective. We assessed the orofacial involvement in JDM, and evaluated the possible association of gingival and mandibular mobility alterations with demographic data, periodontal indices, clinical features, muscle enzyme levels, JDM scores and treatment. Methods. Twenty-six JDM patients were studied and compared with 22 healthy controls. Orofacial evaluation included clinical features, dental and periodontal assessment, mandibular function and salivary flow. Results. The mean current age was similar in patients with JDM and controls (P > 0.05). A unique gingival alteration characterized by erythema, capillary dilation and bush-loop formation was observed only in JDM patients (61 vs 0%, P = 0.0001). The frequencies of altered mandibular mobility and reduced mouth opening were significantly higher in patients with JDM vs controls (50 vs 14%, P = 0.013; 31 vs 0%, P = 0.005). Comparison of the patients with and without gingival alteration showed that the former had lower values of median of cementoenamel junction (-0.26 vs -0.06 mm, P = 0.013) and higher gingival bleeding index (27.7 vs 14%, P = 0.046). This pattern of gingival alteration was not associated with periodontal disease [plaque index (P = 0.332) and dental attachment loss (P = 0.482)]. The medians for skin DAS and current dose of MTX were higher in JDM with gingival alteration (2.5 vs 0.5, P = 0.029; 28.7 vs 15, P = 0.012). A significant association of lower median manual muscle testing with a reduced ability to open the mouth was observed in patients with JDM than those without this alteration (79 vs 80, P = 0.002). Conclusions. The unique gingival pattern associated with cutaneous disease activity, distinct from periodontal disease, suggests that gingiva is a possible target tissue for JDM. In addition, muscle weakness may be a relevant factor for mandibular mobility.

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Background Pulmonary function tests (PFT), particularly spirometry and lung diffusing capacity for carbon monoxide (DL(CO)), have been considered useful methods for the detection of the progression of interstitial asbestos abnormalities as indicated by high-resolution computed tomography (HRCT). However, it is currently unknown which of these two tests correlates best with anatomical changes over time. Methods In this study, we contrasted longitudinal changes (3-9 years follow-up) in PFTs at rest and during exercise with interstitial abnormalities evaluated by HRCT in 63 ex-workers with mild-to-moderate asbestosis. Results At baseline, patients presented with low-grade asbestosis (Huuskonen classes I-II), and most PFT results were within the limits of normality. In the follow-up, most subjects had normal spirometry, static lung volumes and arterial blood gases. In contrast, frequency of DL(CO) abnormalities almost doubled (P < 0.05). Twenty-three (36.5%) subjects increased the interstitial marks on HRCT. These had significantly larger declines in DL(CO) compared to patients who remained stable (0.88 vs. 0.31 ml/min/mm Hg/year and 3.5 vs. 1.2%/year, respectively; P < 0.05). In contrast, no between-group differences were found for the other functional tests, including spirometry (P > 0.05). Conclusions These data demonstrate that the functional consequences of progression of HRCT abnormalities in mild-to-moderate asbestosis are better reflected by decrements in DL(CO) than by spirometric changes. These results might have important practical implications for medico-legal evaluation of this patient population. Am. J. Ind. Med. 54:185-193, 2011. (c) 2010 Wiley-Liss, Inc.

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Background: Significant hemodynamic changes, including preload and afterload modifications, occur during the transition from the fetal to the neonatal environment. The ductus arteriosus closes, pulmonary vascular resistance decreases, and pulmonary blood flow increases. Strain rate (SR) and strain (e) have been proposed as ultrasound indices for quantifying regional wall deformation. This study was designed to determine if these indices can detect variations in regional deformation between early and late neonatal periods. Methods: Data were obtained from 30 healthy neonates (15 male). The initial study was performed at a mean age of 20.1614 hours (exam 1) and the second at 31.962.9 days (exam 2). Apical and parasternal views were used to quantify regional left ventricular (LV) and right ventricular (RV) longitudinal and radial SR and e, and systolic, early, and late diastolic values were calculated from these curves. A paired-samples t test was performed comparing the two groups. Results: Compared with exam 1, LV radial deformation showed significant reductions in peak systolic e in the basal and mid segments (51615% vs 4669%, P < .01). LV longitudinal deformation behaved similarly, showing significant peak systolic e reductions in all measured segments. Systolic SR showed reductions only in the basal and apical segments of the lateral wall and in the mid portion of the inferior wall (-1.9 +/- 0.5 vs -1.7 +/- 0.3 s(-1) and -1.9 +/- 0.4 vs -1.7 +/- 0.2 s(-1), respectively, P = .03). RV longitudinal free and inferior wall systolic SR and e values were significantly higher in exam 2. Conclusions: LV peak systolic e decreases in exam 2 were possibly due to afterload increase and preload decrease. The lower RV initial deformation indices could be attributed to increased afterload caused by physiologic pulmonary hypertension or immature RV contractile properties. SR seemed to be a more robust index than e and less influenced by preload and afterload hemodynamic alteration. (J Am Soc Echocardiogr 2010;23:294-300.)

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Objectives: To analyze the effect of a prevention program oil the estimated cardiovascular risk calculated by three risk scores. Methods: We prospectively evaluated 87 HIV+ patients with elevated cardiovascular risk estimation. Framirigham (FIRS), PROCAM and National Cholesterol Education Program (ATP-III) were applied. Cardiovascular risk was defined as elevated if >10%. All patients received non-pharmacological (diet, exercise, smoking cessation) and, when appropriate, pharmacological therapy. Results: Mean age was 52 years, 92% were male, 39.1% were smokers, 70.1% had hypertension, 18.4% had diabetes. All patients were under HAART, 56.3% were receiving protease inhibitors (131). After 6 months, intervention was associated to significant changes oil triglycerides (298 242 and 206 +/- 135 mg/dL, p<0.05), total-cholesterol (224 +/- 47 and 189 +/- 38 mg/dL, p<0.001). LDL-cholesterol (129 +/- 44 and 109 +/- 30 mg/dL,p<0.001). Frequencies of patients with elevated cardiac risk before and 6 months after intervention were 92% x 27.6% (p < 0.0001), 80.5% x 50.6% (p < 0.0002), and 25.3% x 14.9% (p = 0.12), for FIRS, ATP III and PROCAM, respectively. Conclusions: An intervention Program focused on reduction of traditional risk factors was able to decrease the frequency of patients with HIV infection and elevated cardiovascular risk estimation. FIRS showed greater sensitivity than the other scores. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

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We have designed, built, and tested an early prototype of a novel subxiphoid access system intended to facilitate epicardial electrophysiology, but with possible applications elsewhere in the body. The present version of the system consists of a commercially available insertion needle, a miniature pressure sensor and interconnect tubing, read-out electronics to monitor the pressures measured during the access procedure, and a host computer with user-interface software. The nominal resolution of the system is <0.1 mmHg, and it has deviations from linearity of <1%. During a pilot series of human clinical studies with this system, as well as in an auxiliary study done with an independent method, we observed that the pericardial space contained pressure-frequency components related to both the heart rate and respiratory rate, while the thorax contained components related only to the respiratory rate, a previously unobserved finding that could facilitate access to the pericardial space. We present and discuss the design principles, details of construction, and performance characteristics of this system.

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Background: Tetralogy of Fallot (TOF) is a congenital conotruncal heart defect commonly found in DiGeorge (DGS) and velocardiofacial (VCFS) syndromes. The deletion of chromosome 22q11 has also been demonstrated in sporadic or familial cases of TOF. The aim of the present study was to investigate the frequency of del22q11 in patients with non-syndromic TOF seen at a tertiary Pediatric Cardiology care center. Method: One hundred and twenty three non-syndromic TOF patients were selected and evaluated by history, physical examination and review of medical records. Venous blood was drawn for genomic DNA extraction after informed consent 22q11 microdeletion diagnosis was conducted through a standardized SNP genotyping assay and consecutive homozygosity mapping. Phenotype-genotype correlations regarding cardiac anatomy were conducted. Results: We evaluated 123 non-syndromic TOF patients for a 22q11 deletion. 105 (85.4%) patients presented pulmonary stenosis and 18 (14.6%) had pulmonary atresia. Eight patients (6.5%) were found to have a deletion. Of the deleted patients, three (37.5%) presented pulmonary atresia. We have verified a tendency towards a higher prevalence of pulmonary atresia when comparing TOF patients with and without 22q11 microdeletion. Conclusions: 22q11.2 deletion in non-syndromic TOF patients is present in approximately 6% of patients. We suggest a tendency towards a higher prevalence of pulmonary atresia in non-syndromic TOF patients with 22q11 microdeletion. Molecular genetic screening of non-syndromic TOF patient may be important for the correct care of these patients and a more specific genetic diagnostic and counseling. (C) 2007 Elsevier Ireland Ltd. All rights reserved.

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Previous magnetic resonance imaging (MRI) studies described consistent age-related gray matter (GM) reductions in the fronto-parietal neocortex, insula and cerebellum in elderly subjects, but not as frequently in limbic/paralimbic structures. However, it is unclear whether such features are already present during earlier stages of adulthood, and if age-related GM changes may follow non-linear patterns at such age range. This voxel-based morphometry study investigated the relationship between GM volumes and age specifically during non-elderly life (18-50 years) in 89 healthy individuals (48 males and 41 females). Voxelwise analyses showed significant (p < 0.05, corrected) negative correlations in the right prefrontal cortex and left cerebellum, and positive correlations (indicating lack of GM loss) in the medial temporal region, cingulate gyrus, insula and temporal neocortex. Analyses using ROI masks showed that age-related dorsolateral prefrontal volume decrements followed non-linear patterns, and were less prominent in females compared to males at this age range. These findings further support for the notion of a heterogeneous and asynchronous pattern of age-related brain morphometric changes, with region-specific non-linear features. (C) 2009 Elsevier Inc. All rights reserved.

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Previous functional magnetic resonance imaging (fMRI) studies examined neural activity responses to emotive stimuli in healthy individuals after acute/subacute administration of antidepressants. We now report the effects of repeated use of the antidepressant clomipramine on fMRI data acquired during presentation of emotion-provoking and neutral stimuli on healthy volunteers. A total of 12 volunteers were evaluated with fMRI after receiving low doses of clomipramine for 4 weeks and again after 4 weeks of washout. Fear-, happiness-, anger-provoking and neutral pictures from the International Affective Picture System (IAPS) were used. Data analysis was performed with statistical parametric mapping (P < 0.05). Paired t-test comparisons for each condition between medicated and unmedicated states showed, to negative valence paradigms, decrease in brain activity in the amygdala when participants were medicated. We also demonstrated, across both positive and negative valence paradigms, consistent decreases in brain activity in the medicated state in the anterior cingulate gyrus and insula. This is the first report of modulatory effects of repeated antidepressant use on the central representation of somatic states in response to emotions of both negative and positive valences in healthy individuals. Also, our results corroborate findings of antidepressant-induced temporolimbic activity changes to emotion-provoking stimuli obtained in studies of subjects treated acutely with such agents.

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The importance of epithelial-stroma interaction in normal breast development and tumor progression has been recognized. To identify genes that were regulated by these reciprocal interactions, we cocultured a nonmalignant (MCF10A) and a breast cancer derived (MDA-MB231) basal cell lines, with fibroblasts isolated from breast benign-disease adjacent tissues (NAF) or with carcinoma-associated fibroblasts (CAF), in a transwell system. Gene expression profiles of each coculture pair were compared with the correspondent monocultures, using a customized microarray. Contrariwise to large alterations in epithelial cells genomic profiles, fibroblasts were less affected. In MDA-MB231 highly represented genes downregulated by CAF derived factors coded for proteins important for the specificity of vectorial transport between ER and golgi, possibly affecting cell polarity whereas the response of MCF10A comprised an induction of genes coding for stress responsive proteins, representing a prosurvival effect. While NAF downregulated genes encoding proteins associated to glycolipid and fatty acid biosynthesis in MDA-MB231, potentially affecting membrane biogenesis, in MCF10A, genes critical for growth control and adhesion were altered. NAFs responded to coculture with MDA-MB231 by a decrease in the expression of genes induced by TGF beta 1 and associated to motility. However, there was little change in NAFs gene expression profile influenced by MCF10A. CAFs responded to the presence of both epithelial cells inducing genes implicated in cell proliferation. Our data indicate that interactions between breast fibroblasts and basal epithelial cells resulted in alterations in the genomic profiles of both cell types which may help to clarify some aspects of this heterotypic signaling. (C) 2009 UICC