975 resultados para viscoelasticity, zero stress state
Resumo:
Background/Aims: To present a protocol of immediate surgical repair of myelomeningocele (MMC) after birth (`time zero`) and compare this surgical outcome with the surgery performed after the newborn`s admission to the nursery before the operation. Methods: Data from the medical files of 31 patients with MMC that underwent surgery after birth and after admission at the nursery ( group I) were compared with a group of 23 patients with MMC admitted and prospectively followed, who underwent surgery immediately after birth - `at time zero` ( group II). Results: The preoperative rupture of the MMC occurred more frequently in group I (67 vs. 39%, p < 0.05). The need for ventriculoperitoneal shunt was 84% in group I and 65% in group II and 4 of them were performed during the same anesthetic time as the immediate MMC repair, with no statistically significant difference. Group I had a higher incidence of small dehiscences when compared to group II ( 29 vs. 13%, p < 0.05); however, there was no statistically significant difference regarding infections. After 1 year of follow-up, 61% of group I showed neurodevelopmental delay, whereas only 35% of group II showed it. Conclusions: The surgical intervention carried out immediately after the birth showed benefits regarding a lower incidence of preoperative rupture of the MMC, postoperative dehiscences and lower incidence of neurodevelopmental delay 1 year after birth. Copyright (C) 2009 S. Karger AG, Basel
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Abnormalities in fronto-limbic-striatal white matter (WM) have been reported in bipolar disorder (BD), but results have been inconsistent across studies. Furthermore, there have been no detailed investigations as to whether acute mood states contribute to microstructural changes in WM tracts. In order to compare fiber density and structural integrity within WM tracts between BD depression and remission, whole-brain fractional anisotropy (FA) and mean diffusivity (MD) were assessed in 37 bipolar I disorder (BD-I) patients (16 depressed and 21 remitted), and 26 healthy individuals with diffusion tensor imaging. Significantly decreased FA and increased MD in bilateral prefronto-limbic-striatal white matter and right inferior fronto-occipital, superior and inferior longitudinal fasciculi were shown in all BD-I patients versus controls, as well as in depressed BD-I patients compared to both controls and remitted BD-I patients. Depressed BD-I patients also exhibited increased FA in the ventromedial prefrontal cortex. Remitted BD-I patients did not differ from controls in FA or MD. These findings suggest that BD-I depression may be associated with acute microstructural WM changes.
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The Mini-Mental State Examination (MMSE) is the most widely used instrument for the screening of cognitive impairment worldwide, but its ability to produce valid estimates of dementia in populations of low socioeconomic status and minimal literacy skills has not been adequately established. The authors investigated the psychometric properties of the MMSE in a community-based sample of older Brazilians. Cross-sectional one-phase population-based study of all residents of pre-defined areas of the city of Sao Paulo, aged 65 years or over. The Brazilian version of the MMSE was compared with DSM-IV diagnosis of dementia assessed with a harmonized one-phase procedure developed by the 10/66 Dementia Research Group. Analyses were performed with 1,933 participants of the SPAH study. Receiver operating characteristic analysis showed that the MMSE cut-point of 14/15 was associated with 78.7% sensitivity and 77.8% specificity for the diagnosis of dementia amongst participants with no formal education, and the cut-point 17/18 with 91.9% sensitivity and 89.5% specificity for those with at least 1 year of formal education (areas under the curves 0.87 and 0.94, respectively; P = 0.03). Even with these best fitting cut-points, the MMSE estimate of the prevalence of dementia was four times higher than determined by the DSM-IV criteria. Education, age, sex and income influenced MMSE scores, independently of dementia caseness. The MMSE is an adequate tool for screening dementia in older adults with minimum literacy skills, but misclassification is unacceptably high for older adults who are illiterate, which has serious consequences for research and clinical practice in low and middle income countries, where the proportion of illiteracy among older adults is high.
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Previous studies have shown differences in clinical features of obsessive-compulsive disorder (OCD) between men and women, including mean age at onset of obsessive-compulsive symptoms (OCS), types of OCS, comorbid disorders, course, and prognosis. The aim of this study was to compare male and female Brazilian patients with OCD on several demographic and clinical characteristics. Three hundred thirty Outpatients with OCD (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition [DSM-IV], criteria) who sought treatment at 3 Brazilian public universities and at 2 private practice clinics in the city of Sao Paulo were evaluated. The assessment instruments used were the Yale-Brown Obsessive-Compulsive Scale to evaluate OCD severity and symptoms, the Beck Depression and Anxiety Inventories, the Yale Global Tic Severity Scale, and the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I Disorders to assess psychiatric comorbidity. Fifty-five percent of the patients (n = 182) were men who were significantly more likely than women to be single and to present sexual, religious, and symmetry obsessions and mental rituals. They also presented earlier onset of OCS and earlier symptom interference in functioning, and significantly more comorbid tic disorders and posttraumatic stress disorder. Women, besides showing significantly higher mean scores in the Beck Depression and Anxiety Inventories, were more likely to present comorbid simple phobias, eating disorders in general and anorexia in particular, impulse control disorders in general, and compulsive buying and skin picking in particular. No significant differences were observed between sexes concerning family history of OCS or OCD, and global symptoms severity, either in obsession or compulsive subscale. The present study confirms the presence of sex-related differences described in other countries and cultures. The fact that the OCS start earlier and probably have a worse impact in men can eventually lead to more specific and efficacious treatment approaches for these patients. (C) 2009 Elsevier Inc. All rights reserved.
Resumo:
Prone position may delay the development of ventilator-induced lung injury (VILI), but the mechanisms require better elucidation. In experimental mild acute lung injury (ALI), arterial oxygen partial pressure (Pa(O2)), lung mechanics and histology, inflammatory markers [interleukin (IL)-6 and IL-1 beta], and type III procollagen (PCIII) mRNA expressions were analysed in supine and prone position. Wistar rats were randomly divided into two groups. In controls, saline was intraperitoneally injected while ALI was induced by paraquat. After 24-h, the animals were mechanically ventilated for 1-h in supine or prone positions. In ALI, prone position led to a better blood flow/tissue ratio both in ventral and dorsal regions and was associated with a more homogeneous distribution of alveolar aeration/tissue ratio reducing lung static elastance and viscoelastic pressure, and increasing end-expiratory lung volume and Pa(O2). PCIII expression was higher in the ventral than dorsal region in supine position, with no regional changes in inflammatory markers. In conclusion, prone position may protect the lungs against VILI, thus reducing pulmonary stress and strain. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
Objective: To investigate the effects of low and high levels of positive end-expiratory pressure (PEEP), without recruitment maneuvers, during lung protective ventilation in an experimental model of acute lung injury (ALI). Design: Prospective, randomized, and controlled experimental study. Setting: University research laboratory. Subjects: Wistar rats were randomly assigned to control (C) [saline (0.1 ml), intraperitoneally] and ALI [paraquat (15 mg/kg), intra peritoneally] groups. Measurements and Main Results: After 24 hours, each group was further randomized into four groups (six rats each) at different PEEP levels = 1.5, 3, 4.5, or 6 cm H(2)O and ventilated with a constant tidal volume (6 mL/kg) and open thorax. Lung mechanics [static elastance (Est, L) and viscoelastic pressure (Delta P2, L)] and arterial blood gases were measured before (Pre) and at the end of 1-hour mechanical ventilation (Post). Pulmonary histology (light and electron microscopy) and type III procollagen (PCIII) messenger RNA (mRNA) expression were measured after 1 hour of mechanical ventilation. In ALI group, low and high PEEP levels induced a greater percentage of increase in Est, L (44% and 50%) and Delta P2, L (56% and 36%) in Post values related to Pre. Low PEEP yielded alveolar collapse whereas high PEEP caused overdistension and atelectasis, with both levels worsening oxygenation and increasing PCIII mRNA expression. Conclusions: In the present nonrecruited ALI model, protective mechanical ventilation with lower and higher PEEP levels than required for better oxygenation increased Est, L and Delta P2, L, the amount of atelectasis, and PCIII mRNA expression. PEEP selection titrated for a minimum elastance and maximum oxygenation may prevent lung injury while deviation from these settings may be harmful. (Crit Care Med 2009; 37:1011-1017)
Resumo:
The impact of particle emissions by biomass burning is increasing throughout the world. We explored the toxicity of particulate matter produced by sugar cane burning and compared these effects with equivalent mass of traffic-derived particles. For this purpose, BALB/c mice received a single intranasal instillation of either distilled water (C) or total suspended particles (15 mu g) from an urban area (SP group) or biomass burning-derived particles (Bio group). Lung mechanical parameters (total, resistive and viscoelastic pressures, static elastance, and elastic component of viscoelasticity) and histology were analyzed 24h after instillation. Trace elements and polycyclic aromatic hydrocarbons (PAHs) metabolites of the two sources of particles were determined. All mechanical parameters increased similarly in both pollution groups compared with control, except airway resistive pressure, which increased only in Bio. Both exposed groups showed significantly higher fraction area of alveolar collapse, and influx of polymorphonuclear cells in lung parenchyma than C. The composition analysis of total suspended particles showed higher concentrations of PAHs and lower concentration of metals in traffic than in biomass burning-derived particles. In conclusion, we demonstrated that a single low dose of ambient particles, produced by traffic and sugar cane burning, induced significant alterations in pulmonary mechanics and lung histology in mice. Parenchymal changes were similar after exposure to both particle sources, whereas airway mechanics was more affected by biomass-derived particles. Our results indicate that biomass particles were at least as toxic as those produced by traffic. (C) 2008 Elsevier Inc. All rights reserved.
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Objective: In acute lung injury, recruitment maneuvers have been used to open collapsed lungs and set positive end-expiratory pressure, but their effectiveness may depend on the degree of lung injury. This study uses a single experimental model with different degrees of lung injury and tests the hypothesis that recruitment maneuvers may have beneficial or deleterious effects depending on the severity of acute lung injury. We speculated that recruitment maneuvers may worsen lung mechanical stress in the presence of alveolar edema. Design: Prospective, randomized, controlled experimental study. Setting: University research laboratory. Subjects: Thirty-six Wistar rats randomly divided into three groups (n = 12 per group). Interventions: In the control group, saline was intraperitoneally injected, whereas moderate and severe acute lung injury animals received paraquat intraperitoneally (20 mg/kg [moderate acute lung injury] and 25 mg/kg [severe acute lung injury]). After 24 hrs, animals were further randomized into subgroups (n = 6/each) to be recruited (recruitment maneuvers: 40 cm H(2)O continuous positive airway pressure for 40 secs) or not, followed by 1 hr of protective mechanical ventilation (tidal volume, 6 mL/kg; positive end-expiratory pressure, 5 cm H(2)O). Measurements and Main Results: Only severe acute lung injury caused alveolar edema. The amounts of alveolar collapse were similar in the acute lung injury groups. Static lung elastance, viscoelastic pressure, hyperinflation, lung, liver, and kidney cell apoptosis, and type 3 procollagen and interleukin-6 mRNA expressions in lung tissue were more elevated in severe acute lung injury than in moderate acute lung injury. After recruitment maneuvers, static lung elastance, viscoelastic pressure, and alveolar collapse were lower in moderate acute lung injury than in severe acute lung injury. Recruitment maneuvers reduced interleukin-6 expression with a minor detachment of the alveolar capillary membrane in moderate acute lung injury. In severe acute lung injury, recruitment maneuvers were associated with hyperinflation, increased apoptosis of lung and kidney, expression of type 3 procollagen, and worsened alveolar capillary injury. Conclusions: In the presence of alveolar edema, regional mechanical heterogeneities, and hyperinflation, recruitment maneuvers promoted a modest but consistent increase in inflammatory and fibrogenic response, which may have worsened lung function and potentiated alveolar and renal epithelial injury. (Crit Care Med 2010; 38: 2207-2214)
Can LASSBio 596 and dexamethasone treat acute lung and liver inflammation induced by microcystin-LR?
Resumo:
The treatment of microcystin-LR (MCYST-LR)-induced lung inflammation has never been reported Hence. LASSBio 596, an anti-Inflammatory drug candidate, designed as symbiotic agent that modulates TNF-alpha levels and inhibits phosphodiesterase types 4 and 5, or dexamethasone were tested in this condition Swiss mice were intraperitoneally (i p) injected with 60 mu l of saline (CTRL) or a sub-lethal dose of MCYST-LR (40 mu g/kg). 6 h later they were treated (i p.) with saline (TOX), LASSB10 596 (10 mg/kg, L596), or dexamethasone (1 mg/kg, 0.1 mL, DEXA). 8 h after MCYST-LR injection, pulmonary mechanics were determined, and lungs and livers prepared for histopathology, biochemical analysis and quantification of MCYST-LR. TOX showed significantly higher lung impedance than CTRL and L596, which were similar. DEXA could only partially block the mechanical alterations. In both TOX and DEXA alveolar collapse and inflammatory cell influx were higher than in CTRL and L596, being LASSB10 596 more effective than dexamethasone. TOX showed oxidative stress that was not present in an and L596, while DEXA was partially efficient. MCYST-LR was detected in the livers of all mice receiving MCYST-LR and no recovery was apparent In conclusion, LASSBio 596 was more efficient than dexamethasone in reducing the pulmonary functional impairment induced by MCYST-LR. (C) 2010 Elsevier Ltd. All rights reserved
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We evaluated if repeated stress modulates mucociliary clearance and inflammatory responses in airways of guinea pigs (GP) with chronic inflammation. The GP received seven exposures of ovalbumin or saline 0.9%. After 4th inhalation, animals were submitted to repeated forced swim stressor protocol (5x/week/2 weeks). After 7th inhalation, GP were anesthetized. We measured transepithelial potential difference, ciliary beat frequency, mucociliary transport, contact angle, cough transportability and serum cortisol levels. Lungs and adrenals were removed, weighed and analyzed by morphometry. Ovalbumin-exposed animals submitted to repeated stress had a reduction in mucociliary transport, and an increase on serum cortisol, adrenals weight, mucus wettability and adhesivity, positive acid mucus area and IL-4 positive cells in airway compared to non-stressed ovalbumin-exposed animals (p < 0.05). There were no effects on eosinophilic recruitment and IL-13 positive cells. Repeated stress reduces mucociliary clearance due to mucus theological-property alterations, increasing acid mucus and its wettability and adhesivity. These effects seem to be associated with IL-4 activation. (C) 2010 Elsevier B.V. All rights reserved.
Resumo:
Along the aluminum refining process, alumina (Al(2)O(3)) constitutes the main source of dust. Although aluminum refinery workers present respiratory symptoms with lung functional changes, no conclusive data about lung function impairment after alumina exposure has been so far reported. We examined the pulmonary alterations of exposure to material collected in an aluminum refinery in Brazil. BALB/c mice were exposed in a whole-body chamber for 1 h to either saline (CTRL, n = 11) or to a suspension (in saline) of 8 mg/m(3) of the dust (ALUM, n = 11) both delivered by an ultrasonic nebulizer. Twenty-four hours after exposure lung mechanics were measured by the end-inflation method. Lungs were prepared for histology. ALUM showed significantly higher static elastance (34.61 +/- 5.76 cmH(2)O/mL), elastic component of viscoelasticity (8.16 +/- 1.20 cmH(2)O/mL), pressure used to overcome the resistive component of viscoelasticity (1.62 +/- 0.24 cmH(2)O), and total resistive pressure (2.21 +/- 0.49 cmH(2)O) than CTRL (27.95 +/- 3.63 cmH(2)O/mL, 6.12 +/- 0.99 cmH(2)O/mL, 1.23 +/- 0.19 cmH(2)O, and 1.68 +/- 0.23 cmH(2)O, respectively). ALUM also presented significantly higher fraction area of alveolar collapse (69.7 +/- 1.2%) and influx of polymorphonuclear cells (27.5 +/- 1.1%) in lung parenchyma than CTRL (27.2 +/- 1.1% and 14.6 +/- 0.7%, respectively). The composition analysis of the particulate matter showed high concentrations of aluminum. For the first time it was demonstrated in an experimental model that an acute exposure to dust collected in an aluminum producing facility impaired lung mechanics that could be associated with inflammation.