313 resultados para Melting Peak
Resumo:
The aim of this paper is to study the correlation between the intraocular pressure peaks and fluctuation detected during the water drinking test and the same parameters observed during long-term follow up. This prospective cohort study enrolled 22 eyes of 22 newly diagnosed primary open angle glaucoma patients. After an initial complete ophthalmological examination, patients were started on antiglaucoma medication and returned 4 weeks later to perform the water drinking test. Thereafter, patients were evaluated at least eight times within a period of 6-12 months. The intraocular pressure peaks and fluctuation detected during the water drinking stress test were compared with those observed during regular office visits. Spearman`s correlation coefficient and Bland-Altman Plots were used for statistical analysis. The mean age of participants was 54.3 +/- 8.2 years (+/- SD), 59% were women, and average mean deviation -10.2 +/- 4.5 dB. The mean follow-up period was 8.2 +/- 2.0 months. The average intraocular pressure peaks and fluctuation during the water drinking test were 20.0 +/- 2.9 mmHg and 40 +/- 10%, respectively, and 18.1 +/- 2.8 mmHg and 30 +/- 10% during follow up. Spearman`s correlation coefficients were significant and strong between the intraocular pressure peaks and fluctuation detected during the water drinking test and during the follow-up period (P < 0.001, rho = 0.76 and 0.82, respectively). There was good agreement between the variables. The intraocular pressure peaks and fluctuation detected during the water drinking test showed significant correlation and agreement with the pressures observed during follow-up visits. Stress tests could be used to estimate long-term intraocular pressure variation.
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Emerging data reveal that oral estrogen therapy can increase clinic blood pressure (BP) in postmenopausal women; however, it is important to establish its effects on ambulatory BP, which is a better predictor for target-organ damage. Besides estrogen therapy, aerobic training is widely recommended for post-menopausal women, and it can decrease ambulatory BP levels. This study was designed to evaluate the effect of aerobic training and estrogen therapy on the ambulatory BP of post-menopausal women. Forty seven healthy hysterectomized women were randomly divided (in a double-blind manner) into 4 groups: placebo-control (PLA-CO = 12), estrogen therapy-control (ET-CO = 14), placebo-aerobic training (PLA-AT = 12), and estrogen therapy-aerobic training (ET-AT = 09). The ET groups received estradiol valerate (1 mg/day) and the AT groups performed cycle ergometer, 3x/week at moderate intensity. Hormonal status (blood analysis), maximal cardiopulmonary exercise test (VO(2) peak) and ambulatory BP (24-h, daytime and nighttime) was evaluated before and 6 months after interventions. A significant increase in VO(2) peak was observed only in women who participated in aerobic training groups (+4.6 +/- 1.0 ml kg(-1) min(-1), P=0.00). Follicle-stimulating hormone was a significant decreased in the ET groups (-18.65 +/- 5.19 pg/ml, P=0.00), and it was accompanied by an increase in circulating estrogen (56.1 +/- 6.6 pg/ml). A significant increase was observed in the ET groups for daytime (P=0.01) and nighttime systolic BP (P=0.01), as well as nighttime diastolic BP (P = 0.02). However, daytime diastolic BP was increased only in the ET-CO group (+3.4 +/- 1.2 mmHg, P=0.04), and did not change in any other groups. No significant effect was found in ambulatory heart rate. In conclusion, aerobic training abolished the increase of daytime ambulatory BP induced by estrogen therapy in hysterectomized, healthy, normotensive and postmenopausal women. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
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The aim of this study was to determine whether estrogen therapy enhances postexercise muscle sympathetic nerve activity (MSNA) decrease and vasodilation, resulting in a greater postexercise hypotension. Eighteen postmenopausal women received oral estrogen therapy (ET; n = 9, 1 mg/day) or placebo (n = 9) for 6 mo. They then participated in one 45-min exercise session (cycle ergometer at 50% of oxygen uptake peak) and one 45-min control session (seated rest) in random order. Blood pressure (BP, oscillometry), heart rate (HR), MSNA (microneurography), forearm blood flow (FBF, plethysmography), and forearm vascular resistance (FVR) were measured 60 min later. FVR was calculated. Data were analyzed using a two-way ANOVA. Although postexercise physiological responses were unaltered, HR was significantly lower in the ET group than in the placebo group (59 +/- 2 vs. 71 +/- 2 beats/min, P < 0.01). In both groups, exercise produced significant decreases in systolic BP (145 +/- 3 vs. 154 +/- 3 mmHg, P = 0.01), diastolic BP (71 +/- 3 vs. 75 +/- 2 mmHg, P = 0.04), mean BP (89 +/- 2 vs. 93 +/- 2 mmHg, P = 0.02), MSNA (29 +/- 2 vs. 35 +/- 1 bursts/min, P < 0.01), and FVR (33 +/- 4 vs. 55 +/- 10 units, P = 0.01), whereas it increased FBF (2.7 +/- 0.4 vs. 1.6 +/- 0.2 ml (.) min(-1) (.) 100 ml(-1), P = 0.02) and did not change HR (64 +/- 2 vs. 65 +/- 2 beats/min, P = 0.3). Although ET did not change postexercise BP, HR, MSNA, FBF, or FVR responses, it reduced absolute HR values at baseline and after exercise.
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Background: Patients with diabetes mellitus who undergo coronary stenting are at increased risk of restenosis. It is known that inflammation plays a crucial role in restenosis. Objective: We assessed the inflammatory response to elective coronary stent implantation (CSI) in stable diabetic and nondiabetic patients. Methods: C-reactive protein (CRP), soluble (s) P-selectin, and soluble intercellular adhesion molecule (sICAM)-1 plasma levels were determined in diabetic (n = 51) and nondiabetic (n = 56) patients before and 48 hours and 4 weeks after bare metal stenting (BMS). Results: Diabetic patients presented significantly higher inflammatory marker levels before and after CSI. Nonetheless, diabetic and nondiabetic patients had postintervention peak of markers attained within 48 hours. At baseline, diabetic and nondiabetic patients presented CRP levels of 5.0 +/- 20.1 (P <= 0.04) and 3.8 +/- 9.4 mu g/ml and, at 48 hours postintervention, 22.0 +/- 20.2 (P = 0.001; P = 0.002) and 12.6 +/- 11.3 (P <= 0.0001) mu g/ml. Regarding sP-selectin, diabetic and nondiabetic patients obtained levels of, at baseline, 182 +/- 118 (P <= 0.04) and 105 +/- 48 ng/ml and, at 48 hours, 455 +/- 290 (P = 0.001; P <= 0.01) and 215 +/- 120 (P <= 0.04) ng/ml. For diabetic and nondiabetic patients, sICAM-1 levels were, at baseline, 248 +/- 98 (P <= 0.04) and 199 +/- 94 ng/ml and, at 48 hours, 601 +/- 201 (P = 0.001; P <= 0.01) and 283 +/- 220 (P = 0.001) ng/ml. At 4 weeks, for all patients, markers returned to preprocedural levels: versus before PCI: *P = 0.001, P <= 0.0001; versus nondiabetic patients: #P <= 0.04, P = 0.002, UpsilonP <= 0.01. Conclusions: Diabetic and nondiabetic patients exhibited a temporal inflammatory response after an elective BMS. However, diabetic patients present higher preprocedural levels of CRP, sP-selectin, and sICAM-1 and reveal a further exacerbated inflammatory response after intervention. The differences in inflammatory response may have implications in restenosis within these two sets of patients.
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Data were retrospectively collected from 69 Brazilian patients (45 boys) with growth hormone deficiency (GHD) who received exogenous growth hormone (GH) for a median duration of 4 years (range 1-13 years). Forty-two patients had multiple pituitary hormone deficiencies and 27 had isolated GHD. Peak GH was <7 ng/ml (IRMA) or <3.2 ng/ml (IFMA) after two stimulation tests.. Therapy was started at median age of 10.0 years (range 2.2-21.6 years), bone age of 5.8 years (0.5-13.5 years) and height standard deviation score -4.4 (range -9.3 to -1.6). MRI revealed pituitary abnormalities in 87% of patients. Homozygous mutations in PROP-1, GHRH-R, GH-1 or HESX-1 genes were found in 12 patients. Mean height velocities were 3.3 pretreatment and 10.3, 7.8, 7.4 and 6.4 cm/yr, respectively, during 1-4 years of treatment with GH. In conclusion, the high prevalence (96%) of genetic and/or pituitary abnormalities probably reflects the stringent diagnostic criteria used, and GH replacement resulted in significant catch-up growth.
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Chantler PD, Nussbacher A, Gerstenblith G, Schulman SP, Becker LC, Ferrucci L, Fleg JL, Lakatta EG, Najjar SS. Abnormalities in arterial-ventricular coupling in older healthy persons are attenuated by sodium nitroprusside. Am J Physiol Heart Circ Physiol 300: H1914-H1922, 2011. First published March 4, 2011; doi:10.1152/ajpheart.01048.2010.-The coupling between arterial elastance (E(A); net afterload) and lea ventricular elastance (E(LV); pump performance), known as E(A)/E(LV), is a key determinant of cardiovascular performance and shifts during exercise due to a greater increase in E(LV) versus E(A). This normal exercise-induced reduction in E(A)/E(LV) decreases with advancing age. We hypothesized that sodium. nitroprusside (SNP) can acutely ameliorate the age-associated deficits in E(A)/E(LV). At rest and during graded exercise to exhaustion, EA was characterized as end-systolic pressure/stroke volume and E(LV) as end-systolic pressure/end-systolic volume. Resting E(A)/E(LV): did not differ between old (70 +/- 8 yr. n = 15) and young (30 +/- 5 yr. n = 17) subjects because of a tandem increase in E(A) and E(LV) in older subjects. During peak exercise, a blunted increase in E(LV) in old (7.8 +/- 3.1 mmHg/ml) versus young (11.4 +/- 6.5 mmHg/ml) subjects blunted the normal exercise-induced decline in E(A)/E(LV) in old (0.25 +/- 0.11) versus young (0.16 +/- 0.05) subjects. SNP administration to older subjects lowered resting E(A)/E(LV) by 31% via a reduction E(A) (10%) and an increase in E(LV) (47%) and lowered peak exercise E(A)/E(LV) (36%) via an increase in E(LV) (68%) without a change in E(A). Importantly, SNP attenuated the age-associated deficits in E(A)/E(LV) and E(LV) during exercise, and at peak exercise E(A)/E(LV) in older subjects on drug administration did not differ from young subjects without drug administration. In conclusion, some age-associated deficiencies in E(A)/E(LV), E(A), and E(LV), in older subjects can be acutely abolished by SNP infusion. This is relevant to common conditions in older subjects associated with a significant impairment of exercise performance such as frailty or heart failure with preserved ejection fraction.
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The biomechanics of the sacroiliac joint makes the pelvic segment responsible for proper weight distribution between lower extremities; however, it is known to be susceptible to altered mobility. The objective of this study was to analyze baropodometric responses following thrust manipulation on subjects with sacroiliac joint restrictions. Twenty asymptomatic subjects were submitted to computerized baropodometric analysis before, after, and seven days following sacroiliac manipulation. The variables peak pressure and contact area were obtained at each of these periods as the average of absolute values of the difference between the right and left foot based on three trials. Data revealed significant reduction only in peak pressure immediately after manipulation and at follow-up when compared to pre-manipulative values (p < 0.05). Strong correlation was found between the dominant foot and the foot with greater contact area (r - 0.978), as well as between the side of joint restriction and the foot with greater contact area (r = 0.884). Weak correlation was observed between the dominant foot and the foot with greater peak pressure (r = 0.501), as well as between the side of joint restriction and the foot with greater peak pressure (r = 0.694). The results suggest that sacroiliac joint manipulation can influence peak pressure distribution between feet, but contact area does not seem to be related to the biomechanical aspects addressed in this study. (C) 2011 Elsevier Ltd. All rights reserved.
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Introduction: The photoelasticity is used for assessing the tensions/deformations involved in photoelastic materials when submitted to a given load by the observation of optical effects. The screw performance and mechanical functions are directly associated to the quality of the screws fixation in the vertebrae. Photoelasticity is an important tool to perform comparative studies of this nature. Objective: The aim of this study was to compare, by using photoelasticity, internal stresses produced by the screw with an external diameter of 6 mm, when submitted to two different pullout strengths. Materials and Methods: For this, four photoelastic models were produced. The simulation was conducted by using two pullout strengths: 0.75 and 1.50 kgf. The maximum shear stresses were calculated on 19 points around the screws, using the Tardy compensation method. Results:The values of maximum shear stress were higher with the load of 1.50 kgf. Conclusion: Thus, the screw will be more susceptible to pullout when heavier loads are applied. According to our analysis, we also found that the site with the highest maximum shear stress was found to be at the peak of creast, particularly near the tips of the screws, regardless of the load employed.
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We present a comparative study of the physico-chemical properties, in vitro cytotoxicity and in vivo antibody production of surface-complexed DNA in EPC/DOTAP/DOPE (50/25/25% molar) liposomes and DOTAP/DOPE (50/50% molar) lipoplexes. The study aims to correlate the biological behavior and structural properties of the lipid carriers. We used DNA-hsp65, whose naked action as a gene vaccine against tuberculosis has already been demonstrated. Additionally, surface-complexed DNA-hsp65 in EPC/DOTAP/DOPE (50/25/25% molar) liposomes was effective as a single-dose tuberculosis vaccine. The results obtained showed that the EPC inclusion stabilized the DOTAP/DOPE structure, producing higher melting temperature and lower zeta potential despite a close mean hydrodynamic diameter. Resemblances in morphologies were identified in both structures, although a higher fraction of loaded DNA was not electrostatically bound in EPC/DOTAP/DOPE. EPC also induced a striking reduction in cytotoxicity, similar to naked DNA-hsp65. The proper immune response lead to a polarized antibody production of the IgG2a isotype, even for the cytotoxic DOTAP/DOPE. However, the antibody production was detected at 15 and 30 days for DOTAP/DOPE and EPC/DOTAP/DOPE, respectively. Therefore, the in vivo antibody production neither correlates with the in vitro cytotoxicity, nor with the structural stability alone. The synergistic effect of the structural stability and DNA electrostatic binding upon the surface of structures account for the immunological effects. By adjusting the composition to generate proper packing and cationic lipid/DNA interaction, we allow for the optimization of liposome formulations for required immunization or gene therapy. In a specific manner, our results contribute to studies on the tuberculosis therapy and vaccination. (C) 2009 Elsevier B.V. All rights reserved.
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Here we investigated the possible association between the carboxypeptidase A (CPA)-like activity of the rat mesenteric arterial bed (MAB) perfusate and the ability of this fluid of forming angiotensin (Ang) 1-9 and Ang 1-7 upon incubation with Ang I and Ang II, respectively. Initially, we observed that anion exchange chromatography of the perfusate would consistently split the characteristic Z-Val-Phe-hydrolyzing activity of CPA-like enzymes into five distinct peaks, whose proteolytic activities were then determined using also Ang I and Ang II as substrates. The resulting proteolytic profile for each peak indicated that rat MAB perfusate contains a complex mixture of carboxypeptidases; tentatively, five carboxypeptidases were distinguished based on their substrate preferences toward Z-Val-Phe. Ang I and Ang II. The respective reactions, namely, Z-Val-Phe cleavage, Ang I to Ang 1-9 conversion and Ang II to Ang 1-7 conversion, were inhibited by 1,10-phenanthroline and nearly fully blocked by potato carboxypeptidase inhibitor. Also, all the CPA-like activity peaks prepared by anion exchange chromatography were tested negative for contaminating Ang I-converting enzyme-2, cathepsin A and prolylcarboxypeptidase. Overall, our results indicate that rat MAB perfusate contains a multiplicity of Ang I and Ang II-processing CPA-like enzymes whose proteolytic specificities suggest they might perform peculiar regulatory roles in the local resin-angiotensin system. (C) 2008 Elsevier B.V. All rights reserved.
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Background: Magnesium (Mg) use has the potential to promote bronchodilatation and to improve lung function in obstructive diseases. IV administration of Mg during exacerbations of chronic obstructive pulmonary disease (COPD) has led to improved peak flow. This study aimed to investigate the effects of acute IV Mg loading on respiratory parameters of stable COPD patients. Material/Methods: This was a randomized, double-blind, placebo-controlled crossover study. Twenty-two male COPD patients (64 +/- 6 years old, FEV1: 49 +/- 20%) received an IV infusion of 2 g of magnesium sulfate or placebo on two distinct occasions. Spirometry and mouth maximal respiratory pressures were obtained before and 45 minutes after the infusions. Results: Mg use led to significant changes in functional respiratory capacity (-0.48 1,95% CI: -0.96, -0.01), inspiratory capacity (0.21 1,95% CI: 0.04, 0.37). The treatment was also associated with a marginally significant decrease in residual volume (-0.47 1,95% CI: -0.96, 0.02, p=0.06). Conclusions: Acute IV Mg loading in stable COPD patients was associated with a reduction in lung hyperinflation and improvement of respiratory muscle strength. The clinical potential for chronic magnesium supplementation in COPD deserves further investigation.
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Adding a long-acting beta(2)-agonist to inhaled corticosteroids (ICS) for asthma treatment is better than increasing ICS dose in improving clinical status, although there is no consensus about the impact of this regimen on inflammation. In this double-blind, randomized, parallel group study, asthmatics with moderate to severe disease used budesonide (400 mcg/day) for 5 weeks (run-in period); then they were randomized to use budesonide (800 mcg/day - BUD group) or budesonide plus formoterol (400 mcg and 24 mcg/day, respectively - FORMO group) for 9 weeks (treatment period). Home PEF measurements, symptom daily reporting, spirometry, sputum induction (for differential cell counts and sputum cell cultures), and hypertonic saline bronchial challenge test were performed before and after treatments. TNF-alpha, IL-4 and eotaxin-2 levels in the sputum and cell culture supernatants were determined. Morning and night PEF values increased in the FORMO group during the treatment period (p < 0.01), from 435 +/- 162 to 489 +/- 169 and 428 +/- 160 to 496 +/- 173 L/min, respectively. The rate of exacerbations in the FORMO group was lower than in the BUD group (p < 0.05). Neutrophil counts in sputum increased in both groups (p < 0.05) and leukocyte viability after 48 h-culture increased in the FORMO group (p < 0.05). No other parameter changed significantly in either group. This study showed that adding formoterol to budesonide improved home PEF and provided protection from exacerbations, although increase of leukocyte viability in cell culture may be a matter of concern and needs further investigation. (C) 2008 Elsevier Ltd. All rights reserved.
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Objective: The physiological role of parathormone (PTH) in the maintenance of bone mass in humans has not been fully defined. The main objective of the present study was to evaluate basal and EDTA-stimulated PTH levels in Young women (Group Y = 30.9 years, N = 7) and in women in late menopause (Group M = 64.7 years, N = 7) and their relationship to bone mineral density. Methods: The PTH secretion test was performed by induction of hypocalcemia through intravenous administration of EDTA for 2 h. Blood samples were collected every 10 min and used for ionic calcium and PTH measurements. During the basal period, an additional sample was collected for the determination of osteocalcin, FSH, and estradiol. A sample of early morning second voided urine was collected for analysis of deoxypiridinoline and creatinine Lis well as bone mass density (BMD) was determined by dual X-ray energy absorptiometry (DEXA). Results: The aged patients presented lower femoral BMD (Y = 0.860 g/cm(2) vs. M = 0.690 g/cm(2), P < 0.01), With four of them having a T score lower than - 2.5 S.D. Basal, and during the EDTA infusion, PTH values were similar in both groups. However, among aged volunteers, the rise in PTH levels was higher for subjects with normal bone mass (NM: peak = 236 pg/ml) than for subjects with osteoporosis (OM: peak = 134.4 pg/ml). Conclusions: The present results suggest that PTH can have a modulating effect on the rate of bone loss during late menopause. (c) 2007 Elsevier Ireland Ltd. All rights reserved.
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In the present study, BALB/c mice were used to develop a model for the hepatic injury associated to dengue infection. Histological analysis after subcutaneous inoculation with a low viral dose of dengue-2 virus showed Kupffer cell hyperplasia and an increased inflammatory cellular infiltrate next to the bile ducts on days 5, 7 and 14 post-inoculation, mainly characterized by the presence of mononuclear cells. The liver mRNA transcription level of IL-1 beta was highest on the 5th day post-infection (p.i.) and decreased by the 21st day, TNF-alpha showed a peak of mRNA transcription after 14 days p.i. coinciding with the regression of cellular infiltrates and elevated expression of TGF-beta mRNA. Serum AST and ALT levels were slightly elevated at 7 and 14 days post-infection. Dengue-2 RNA levels were undetectable in the liver on any of the days following inoculation. Our observations suggest that, as it is true for humans, the animals undergo a transient and slight liver inflammation, probably due to local cytokine production and cellular infiltration in the liver. (C) 2010 Elsevier Inc. All rights reserved.
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The paraventricular nucleus of the hypothalamus (PVN) has been implicated in several aspects of cardiovascular control. Stimulation of the PVN evokes changes in blood pressure and heart rate. Additionally, this brain area is connected to several limbic structures implicated in behavioral control, as well as to forebrain and brainstem structures involved in cardiovascular control. This evidence indicates that the PVN may modulate cardiovascular correlates of behavioral responses to stressful stimuli. Acute restraint is an unavoidable stressor that evokes marked and sustained cardiovascular changes, which are characterized by elevated mean arterial pressure (MAP) and an intense heart rate (HR) increase. We report on the effect of inhibition of PVN synapses on MAP and HR responses evoked by acute restraint in rats. Bilateral microinjection of the nonspecific synaptic blocker cobalt (CoCl2, 1mM/100nl) into the PVN did not change the HR response or the initial peak of the MAP response to restraint stress, but reduced the area under the curve of the MAP response. Moreover, bilateral microinjection of cobalt in areas surrounding the PVN did not change the cardiovascular response to restraint. These results indicate that synapses in the PVN are involved in the neural pathway that controls blood pressure changes evoked by restraint.