969 resultados para frequency scaling factors


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Objectives: The aim of this study was to determine whether the addition of the measurement of bilateral hip bone mineral density (BMD) has an impact on indications for osteoporosis (OP) treatment in community-dwelling elderly individuals, based on criteria from the National Osteoporosis Foundation (NOF). Methods: In total, 605 consecutive community-dwelling elderly individuals who were 65 years and older were evaluated. Dual energy X-ray absorptiometry was used to determine the lowest T-score in the lumbar spine + unilateral hip, the bilateral hips, and the lumbar spine + bilateral hips. Risk factors associated with the lowest T-score in these three conditions were applied to indicate treatment in accordance with NOF criteria. McNemar`s test was used to assess the difference of adding bilateral hip BMD measurements. Results: There was a significant difference in the frequency of pharmacological indication using NOF criteria together with the lowest T-score for the three tests (72.8% for lumbar spine + bilateral hips and 71.2% for lumbar spine + unilateral hip; p=0.002). A higher frequency of treatment indication was also observed for lumbar spine + unilateral hip (71.2%) compared to bilateral hips (61.1%) (p<0.001). The discrepancies in treatment appeared to be more evident in women when analyzed by gender distribution. Conclusion: Our finding supports the theory that evaluation of the bilateral hips with the lumbar spine seems to be more sensitive measure for identifying patients with an osteoporosis treatment indication. Furthermore, despite the well-known artifact in the lumbar spine, this site should not be excluded when determining the indication for OP treatment in elderly people. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

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Background: Sudden unexpected cardiac death (SUCD) accounts for approximately 25% of deaths from ischaemic heart disease (IHD) but is relatively poorly understood because of the difficulties involved in researching aetiology. Clinical differences between instances of SUCD and those cases of acute chest pain that survive long enough to be proven as myocardial infarction but are eventually fatal might reflect differences in aetiology. Aims: To determine the risk factors for sudden unexpected cardiac death in Tasmanian men. Methods: A population-based case-control method was used with the study population, an estimated 125,225 men aged 25-74 years living in the island State of Tasmania, Australia. The case group of 102 men who had a SUCD was validated using necropsy reports, hospital records and information provided by the usual general practitioner. Cases were matched with 204 community controls. Spouses or partners of eligible subjects answered a detailed questionnaire. Multi-variate odds ratios (ORs) for risk factors were calculated using stepwise analysis. Results: Risk factors measured included: smoking habit, treated hypertension, hypercholesterolaemia, diabetes mellitus, family history of LHD, alcohol intake and exercise habits. Independent risk factors for SUCD were: history of diabetes mellitus (OR=4.2, 95% CI: 1.39, 12.81), current smoking status (OR=3.5, 95% CI: 1.80, 6.82), and family history of IHD (OR=2.6, 95% CI: 1.34, 4.92). Conclusions: Some accepted risk factors for acute myocardial infarction (AMI) also predict sudden death in men with no history of coronary disease. Efforts to reduce smoking, the incidence of diabetes mellitus and mean blood pressure must be continued as SUCD is, by definition, untreatable but is potentially avoidable in many instances.

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Metabolic syndrome is characterized by a combination of various cardiovascular risk factors (age, gender, smoking, hypertension and dyslipidemia) that imply additional cardiovascular morbidity that is greater than the sum of the risks associated with each individual component. Herein, the authors review the rheumatological diseases in which metabolic syndrome has been studied: gout, osteoarthritis, systemic lupus erythematosus, rheumatoid arthritis, Sjogren`s syndrome and ankylosing spondylitis. The prevalence of metabolic syndrome in these disorders varies from 14% to 62.8%. The great majority of these studies demonstrated that this frequency was higher in rheumatological diseases than in the control populations, suggesting that either the presence or the treatment of those diseases seems to influence the risk of developing metabolic syndrome. (C) 2009 Elsevier B.V. All rights reserved.

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Objective. To examine possible risk factors in post-stroke depression (PSD) other than site of lesion in the brain Data sources. 191 first-ever stroke patients were examined physically shortly after their stroke and examined psychiatrically and physically 4 months post-stroke. Setting. A geographically defined segment of the metropolitan area of Perth, Western Australia, from which all strokes over a course of 18 months were examined (the Perth Community Stroke Study). Measures. Psychiatric Assessment Schedule, Mini Mental State Examination, Barthel Index, Frenchay Activities Index, physical illness and sociodemographic data were collected. Post-stroke depression (PSD) included both major depression and minor depression (dysthymia without the 2-year time stipulation) according to DSM-III (American Psychiatric Association) criteria. Patients depressed at the time of the stroke were excluded. Patients. 191 first-ever stroke patients, 111M, 80F, 28% had PSD, 17% major and 11% minor depression. Results. Significant associations with PSD at 4 months were major functional impairment, living in a nursing home, being divorced and having a high pre-stroke alcohol intake (M only). There was no significant association with age, sex, social class, cognitive impairment or pre-stroke physical illness. Conclusion. Results favoured the hypothesis that depression in an unselected group of stroke patients is no more common, and of no more specific aetiology, than it is among elderly patients with other physical illness.

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A method is presented for computing the fields produced by radio frequency probes of the type used in magnetic resonance imaging. The effects of surrounding the probe with a shielding coil, intended to eliminate stray fields produced outside the probe, are included. An essential feature of these devices is the fact that the conducting rungs of the probe are of finite width relative to the coil radius, and it is therefore necessary to find the distribution of current within the conductors as part of the solution process. This is done here using a numerical method based on the inverse finite Hilbert transform, applied iteratively to the entire structure including its shielding coils. It is observed that the fields are influenced substantially by the width of the conducting rungs of the probe, since induced eddy currents within the rungs become more pronounced as their width is increased. The shield is also shown to have a significant effect on both the primary current density and the resultant fields. Quality factors are computed for these probes and compared with values measured experimentally.

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Lima GA, Anhe GF, Giannocco G, Nunes MT, Correa-Giannella ML, Machado UF. Contractile activity per se induces transcriptional activation of SLC2A4 gene in soleus muscle: involvement of MEF2D, HIF-1a, and TR alpha transcriptional factors. Am J Physiol Endocrinol Metab 296: E132-E138, 2009. First published October 28, 2008; doi: 10.1152/ajpendo.90548.2008.-Skeletal muscle is a target tissue for approaches that can improve insulin sensitivity in insulin-resistant states. In muscles, glucose uptake is performed by the GLUT-4 protein, which is encoded by the SLC2A4 gene. SLC2A4 gene expression increases in response to conditions that improve insulin sensitivity, including chronic exercise. However, since chronic exercise improves insulin sensitivity, the increased SLC2A4 gene expression could not be clearly attributed to the muscle contractile activity per se and/or to the improved insulin sensitivity. The present study was designed to investigate the role of contractile activity per se in the regulation of SLC2A4 gene expression as well as in the participation of the transcriptional factors myocyte enhancer factor 2D (MEF2D), hypoxia inducible factor 1a (HIF-1a), and thyroid hormone receptor-alpha (TR alpha). The performed in vitro protocol excluded the interference of metabolic, hormonal, and neural effects. The results showed that, in response to 10 min of electrically induced contraction of soleus muscle, an early 40% increase in GLUT-4 mRNA (30 min) occurred, with a subsequent 65% increase (120 min) in GLUT-4 protein content. EMSA and supershift assays revealed that the stimulus rapidly increased the binding activity of MEF2D, HIF-1a, and TR alpha into the SLC2A4 gene promoter. Furthermore, chromatin immunoprecipitation assay confirmed, in native nucleosome, that contraction induced an approximate fourfold (P < 0.01) increase in MEF2D and HIF-1a-binding activity. In conclusion, muscle contraction per se enhances SLC2A4 gene expression and that involves MEF2D, HIF-1a, and TR alpha transcription factor activation. This finding reinforces the importance of physical activity to improve glycemic homeostasis independently of other additional insulin sensitizer approaches.

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We reviewed the data of 307 patients treated with autologous bone marrow transplantation with the aim to identify factors associated with poor hematopoietic stern cell (HSC) mobilization after administration of cyclophosphamide and granulocyte-colony stimulating factor. Success in mobilization was defined when >= 2.0 x 10(6) CD34+ cells/kg weight could be collected with <= 3 leukapheresis procedures. Success was observed in 260 patients (84.7%) and nonsuccess in 47 patients (15.3%). According to the stepwise regression model: diagnosis, chemotherapy load, treatment with mitoxantrone and platelet count before mobilization were found to be independent predictive factors for HSC mobilization. These results could help in the previous recognition of patients at risk for non response to mobilization and allow to plan an alternative protocol for this group of patients. (C) 2008 Elsevier Ltd. All rights reserved.

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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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Purpose: Animal models of diseases are extremely important in the study of the physiopathogenesis of human diseases and for testing novel therapeutic interventions. The present study aimed to develop an animal model that simulates human allergic conjunctivitis and to study how allergic response may be influenced by the allergen dose used for immunization and by genetic factors. Methods: Sixty C57Bl/6 mice and 60 BALB/c mice were immunized with placebo, or 5 mu g or 500 mu g of allergen derived from Dermatophagoides pteronyssinus. After ocular challenge, the mice were examined in order to clinically verify the occurrence or not of conjunctivitis. Material obtained from animals was used for total and specific IgE and IgG1 dosage, for assays of Der p-specific lymphocyte proliferation and supernatant cytokine dosage, and for histopathological evaluation of conjunctiva. Results: We developed a murine model of allergic conjunctivitis induced by D. pteronyssinus. The model is similar to human disease both clinically and according to laboratory findings. In mouse, conjunctivitis was associated with a Th2 cytokine profile. However, IL-10 appeared to be involved with disease blockade. Mice of different strains have distinct immune responses, depending on the sensitization dose. Conclusions: The murine model developed is suitable for the study of immunopathogenesis and as a template for future therapies. Using BALB/c and C57BL/6 mice, we demonstrated that genetic factors play a role in determining susceptibility and resistance, as well as in establishing the allergen concentration needed to induce or to block disease development.

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The aim of this study was to evaluate risk factors for low bone mineral density (BMD) and vertebral fractures, in juvenile systemic lupus (JSLE). Thirty-one consecutive patients with JSLE were compared with 31 gender- and age-matched healthy controls. BNID and body composition from all participants were measured using dual-energy X-ray absorptiometry. Vertebral fractures were defined as a reduction of >= 20% of the vertebral height for all patients. Lumbar spine and total femur BMD was significantly decreased in patients compared with controls (P = 0.021 and P = 0.023, respectively). A high frequency of vertebral fractures (22.58%) was found in patients with JSLE. Analysis of body composition revealed lower lean mass (P = 0.033) and higher fat mass percentage (P = 0.003) in patients than in controls. Interestingly, multiple linear regression using BMD as a dependent variable showed a significant association with lean mass in lumbar spine (R(2) = 0.262; P = 0.004) and total femur (R(2) = 0.419, P = 0.0001), whereas no association was observed with menarche age, SLE Disease Activity Index, Systemic Lupus International Collaborating Clinics/American College of Rheumatology, and glucocorticoid. This study indicates that low BMD and vertebral fractures are common in JSLE, and the former is associated with low lean mass, suggesting that muscle rehabilitation may be an additional target for bone therapeutic approach.

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Background: To investigate the association between cardiovascular risk-factor profile and migraine in the elderly, we evaluated a population sample of ageing men and women (65 years or more) living in a low-income area in the city of Sao Paulo, Brazil. Patients and Methods: We investigated migraine status and cardiovascular profile from a baseline of 1450 participants (65-102 years of age) of the Sao Paulo Ageing & Health Study (SPAH), a longitudinal population-based study with low-income elderly in Brazil. The following age and sex-adjusted cardiovascular risk factors were analyzed: blood pressure, pulse pressure, serum total and high-density lipoprotein cholesterol, body mass index, smoking, history of hypertension, diabetes and the 10-year risk of myocardial infarction or coronary heart disease death based on the Framingham Risk Score. Results: The overall prevalence of migraine was 11.4%, and it was 3 times more frequent among women than men (15.3% vs 5.4%; P < 0.0001). Migraineurs were younger than non-migraineurs (mean age 70.6 years vs 72.1 years; P = 0.001, respectively). There was no statistically significant difference regarding the cardiovascular risk-factor profile after adjustment for age and sex among migraineurs and non-migraineurs. Only a decrease in the risk of hypertension among women (OR 0.58; 95% CI 0.38-0.90; P = 0.01) was also observed even after adjustment for age. Conclusions: Overall, we did not find a worse cardiovascular risk profile among elderly migraineurs. An inverse association between hypertension and migraine in women warrants further investigation.

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To identify the underlying mechanism of amenorrhea in juvenile systemic lupus erythematosus (JSLE) patients, thirty-five (11.7%) JSLE patients with current or previous amenorrhea were consecutively selected among the 298 post-menarche patients followed in 12 Brazilian pediatric rheumatology centers. Pituitary gonadotrophins [follicle-stimulating hormone (FSH) and luteinizing hormone (LH)] and estradiol were evaluated in 32/35 patients, and prolactin and total testosterone in 29/35 patients. Patient`s medical records were carefully reviewed according to demographic, clinical and therapeutic findings. The mean duration of amenorrhea was 7.2 +/- A 3.6 months. Low FSH or LH was observed in 7/32 (22%) JSLE patients and normal FSH or LH in 25 (78%). Remarkably, low levels of FSH or LH were associated with higher frequency of current amenorrhea (57% vs. 0%, P = 0.001), higher median disease activity (SLEDAI) and damage (SLICC/ACR-DI) (18 vs. 4, P = 0.011; 2 vs. 0, P = 0.037, respectively) and higher median current dose of prednisone (60 vs. 10 mg/day, P = 0.0001) compared to normal FSH or LH JSLE patients. None of them had decreased ovarian reserve and premature ovarian failure. Six of 29 (21%) patients had high levels of prolactin, and none had current amenorrhea. No correlations were observed between levels of prolactin and SLEDAI, and levels of prolactin and SLICC/ACR-DI scores (Spearman`s coefficient). We have identified that amenorrhea in JSLE is associated with high dose of corticosteroids indicated for active disease due to hypothalamic-pituitary-ovary axis suppression.

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Objectives: To compare prognosis parameters and arterial site involvement in Takayasu arteritis (TA) patients with disease onset at age <= 18 and >= 21 years. Methods: Sixty-two TA patients [American College of Rheumatology (ACR) and European League Against Rheumatism/Paediatric Rheumatology European Society (EULAR/PreS) criteria] were enrolled consecutively and divided into two groups according to disease onset, and matched for disease duration: juvenile TA patients aged <= 18 years (n = 17) and adult TA patients aged >= 21 years (n = 45). The protocol evaluated the following prognostic factors: aortic insufficiency, ischaemic retinopathy, severe systemic hypertension, and arterial aneurysms. In addition, death and remission [defined as stable disease > 6 months (no complaints without immunosuppressive and prednisone use) and normal erythrocyte sedimentation rate (ESR)] were also analysed. Stenosis and aneurisms were investigated by magnetic angioresonance or arteriography and angiographic classification was defined according to Hata criteria. Results: Mean disease duration was similar in the juvenile and adult TA groups (13.50 +/- 10.73 vs. 13.80 +/- 7.17 years, p = 0.092) and a trend to a lower predominance of female gender in the juvenile TA group was observed (64.71% vs. 88.89%, p = 0.056). The prognosis was distinct in the two groups, with juvenile patients having a lower frequency of disease remission (23.53% vs. 55.56%, p = 0.04) and a significantly higher frequency of aneurism (41.0% vs. 11.1%, p = 0.013). Almost half of the juvenile TA patients had left renal stenosis, a frequency significantly higher than in the adult TA group (41.18% vs. 11.10%, p = 0.013), whereas the stenosis frequency was comparable in all other vascular sites evaluated. No differences were observed between the two groups regarding the frequency of aortic insufficiency, ischaemic retinopathy, severe systemic arterial hypertension, vascular procedures, and mortality. Angiographic classification revealed a similar distribution of arterial involvement in both groups (p > 0.05). Conclusions: Juvenile TA patients have distinct characteristics, with a peculiar renal vascular involvement, the presence of aneurism, and a more refractory disease compared with adult TA patients.

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Various members of the bZip and bHLH-Zip families of eukaryotic transcription factors, including Jun, Fos, and Myc, have been identified as oncoproteins; mutation or deregulated expression of these proteins leads to certain types of cancer. These proteins can only bind to their cognate DNA enhancer sites following homodimerization, or heterodimerization with another family member, via their leucine zipper domain. Thus, a novel anticancer strategy would be to inhibit dimerization of these proteins, thereby blocking their DNA binding and transactivation functions. In this paper we show that it is possible to rationally design leucine zipper peptides that bind with high affinity to the leucine zipper dimerization domains of c-Jun and c-Fos, thus preventing the formation of functional c-Jun homodimers and c-Jun:c-Fos heterodimers; we refer to such peptides as superzippers (SZs). In vivo, c-Jun:SZ and c-Fos:SZ heterodimers should be nonfunctional as they lack one of the two basic domains that are essential for DNA binding. While the transport of a peptidic agent into cells often poses a severe obstacle to its therapeutic use, we show that a 46-residue leucine zipper peptide can be transported into HeLa cells by coupling it to a 17-residue carrier peptide from the Antennapedia homeodomain, thus paving the way for detailed studies of the therapeutic potential of superzipper peptides.