Microstructural characterization of as-cast Cr-Si alloys

This work presents results of microstructural characterization of as-cast Cr-Si alloys. The alloys were prepared by arc melting pure Cr (min. 99.996%) and Si (min. 99.998%) powder mixtures under argon atmosphere in a water-cooled copper crucible with nonconsumable tungsten electrode and titanium getter. The phases were identified by scanning electron microscopy (SEM), using the back-scattered electron (BSE) image mode and X-ray diffraction (XRD). The results confirm the currently accepted Cr-Si phase diagram in terms of the invariant reactions and solid phases present in this system. Small corrections are proposed for the compositions of the liquid phase in the following reactions: (i) L double left right arrow Cr-ss+Cr3Si, from 15 to 16 at.% Si; (ii) L+alpha Cr5Si3 double left right arrow CrSi, from 51 at.% Si to slightly above 53 at.% Si; (iii) L double left right arrow CrSi+CrSi2, from 56 to slightly above 57 at.% Si; (iv) L double left right arrow CrSi2+Si, from 82 to slightly above 85 at.% Si. (c) 2006 Elsevier Inc. All rights reserved.

Influence of visual feedback on pelvic floor muscle strength

Objective: The objective of this study is to evaluate the visual feedback influence on pelvic floor muscle contraction. Study design: Seventeen nulliparous, urinary-continent women participated in this study. Pelvic floor muscle strength with and without the use of visual feedback was measured with a dynamometric speculum in two directions (anteroposterior and left-right). To compare the mean strength values with and without the use of visual feedback, the t test was applied. Results: There was no significant difference between the pelvic floor muscle anteroposterior strength values with and without the use of visual feedback (p = 0.30), and no significant difference for the left-right strength (p = 0.37). Conclusion: There was no difference between the pelvic floor muscle strength values with and without the use of visual feedback. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

Hypertrophy and neuron loss: structural changes in sheep SCG induced by unilateral sympathectomy

Recently, superior cervical ganglionectomy has been performed to investigate a variety of scientific topics from regulation of intraocular pressure to suppression of lingual tumour growth. Despite these recent advances in our understanding of the functional mechanisms underlying superior cervical ganglion (SCG) growth and development after surgical ablation, there still exists a need for information concerning the quantitative nature of the relationships between the removed SCG and its remaining contralateral ganglion and between the remaining SCG and its modified innervation territory. To this end, using design-based stereological methods, we have investigated the structural changes induced by unilateral ganglionectomy in sheep at three distinct timepoints (2, 7 and 12 weeks) after surgery. The effects of time, and lateral (left-right) differences, were examined by two-way analyses of variance and paired t-tests. Following removal of the left SCG, the main findings were: (i) the remaining right SCG was bigger at shorter survival times, i.e. 74% at 2 weeks, 55% at 7 weeks and no increase by 12 weeks, (ii) by 7 weeks after surgery, the right SCG contained fewer neurons (no decrease at 2 weeks, 6% fewer by 7 weeks and 17% fewer by 12 weeks) and (iii) by 7 weeks, right SCG neurons were also larger and the magnitude of this increase grew substantially with time (no rise at 2 weeks, 77% by 7 weeks and 215% by 12 weeks). Interaction effects between time and ganglionectomy-induced changes were significant for SCG volume and mean perikaryal volume. These findings show that unilateral superior cervical ganglionectomy has profound effects on the contralateral ganglion. For future investigations, it would be interesting to examine the interaction between SCGs and their innervation targets after ganglionectomy. Is the ganglionectomy-induced imbalance between the sizes of innervation territories the milieu in which morphoquantitative changes, particularly changes in perikaryal volume and neuron number, occur? Mechanistically, how would those changes arise? Are there any grounds for believing in a ganglionectomy-triggered SCG cross-innervation and neuroplasticity? (C) 2011 ISDN. Published by Elsevier Ltd. All rights reserved.

Quantification of Regional Left and Right Ventricular Deformation Indices in Healthy Neonates by Using Strain Rate and Strain Imaging

Background: Color Doppler myocardial imaging (CDMI) allows the calculation of local longitudinal or radial strain rate (SR) and strain (epsilon). The aims of this study were to determine the feasibility and reproducibility of longitudinal and radial SR and epsilon in neonates during the first hours of life and to establish reference values. Methods: Data were obtained from 55 healthy neonates (29 male; mean age, 20 +/- 14 hours; mean birth weight, 3,174 +/- 374 g). Apical and parasternal views quantified regional longitudinal and radial SR and epsilon in differing ventricular wall segments. Values at peak systole, early diastole, and late diastole were calculated from the extracted curves. CDMI data acquired at 300 +/- 50 frames/s were analyzed offline. Three consecutive cardiac cycles were measured during normal respiration. The timing of specific systolic or diastolic regional events was determined. Multiple comparisons between walls and segments were made. Results: Left ventricular (LV) longitudinal deformation showed basal differences compared with apical segments within one specific wall. Right ventricular (RV) longitudinal deformation was not homogeneous, with significant differences between basal and apical segments. Longitudinal 3 values were higher in the RV free basal and middle wall segments compared with the left ventricle. In the RV free wall apical segment, longitudinal SR and 3 were maximal. LV systolic SR and epsilon values were higher radially compared with longitudinally (radial peak systolic SR midportion, 2.9 +/- 0.6 s(-1); radial peak systolic epsilon 53.8 +/- 19%; longitudinal peak systolic SR midportion, -1.8 +/- 0.5 s(-1); longitudinal peak systolic epsilon, -24.8 +/- 3%; P < .01). Longitudinal systolic epsilon and SR interobserver variability values were 1.2% and 0.7%, respectively. Conclusion: Ultrasound-based SR and 3 imaging is a practical and reproducible clinical technique in neonates, allowing the calculation of regional longitudinal and radial deformation in RV and LV segments. These regional SR and epsilon indices represent new, noninvasive parameters that can quantify normal neonate regional cardiac function. Independent from visual interpretation, they can be used as reference values for diagnosis in ill neonates. (J Am Soc Echocardiogr 2009;22:369-375.)

Right Orbitofrontal Corticolimbic and Left Corticocortical White Matter Connectivity Differentiate Bipolar and Unipolar Depression

Objectives: The absence of pathophysiologically relevant diagnostic markers of bipolar disorder (BD) leads to its frequent misdiagnosis as unipolar depression (UD). We aimed to determine whether whole brain white matter connectivity differentiated BD from UD depression. Methods: We employed a three-way analysis of covariance, covarying for age, to examine whole brain fractional anisotropy (FA), and corresponding longitudinal and radial diffusivity, in currently depressed adults: 15 with BD-type I (mean age 36.3 years, SD 12.0 years), 16 with recurrent UD (mean age 32.3 years, SD 10.0 years), and 24 healthy control adults (HC) (mean age 29.5 years, SD 9.43 years). Depressed groups did not differ in depression severity, age of illness onset, and illness duration. Results: There was a main effect of group in left superior and inferior longitudinal fasciculi (SLF and ILF) (all F >= 9.8; p <= .05, corrected). Whole brain post hoc analyses (all t >= 4.2; p <= .05, corrected) revealed decreased FA in left SLF in BD, versus UD adults in inferior temporal cortex and, versus HC, in primary sensory cortex (associated with increased radial and decreased longitudinal diffusivity, respectively); and decreased FA in left ILF in UD adults versus HC. A main effect of group in right uncinate fasciculus (in orbitofrontal cortex) just failed to meet significance in all participants but was present in women. Post hoc analyses revealed decreased right uncinate fasciculus FA in all and in women, BD versus HC. Conclusions: White matter FA in left occipitotemporal and primary sensory regions supporting visuospatial and sensory processing differentiates BD from UD depression. Abnormally reduced FA in right fronto-temporal regions supporting mood regulation, might underlie. predisposition to depression in BD. These measures might help differentiate pathophysiologic processes of BD versus UD depression.

Abnormal Left and Right Amygdala-Orbitofrontal Cortical Functional Connectivity to Emotional Faces: State Versus Trait Vulnerability Markers of Depression in Bipolar Disorder

Background: Amygdala-orbitofrontal cortical (OFC) functional connectivity (FC) to emotional stimuli and relationships with white matter remain little examined in bipolar disorder individuals (BD). Methods: Thirty-one BD (type 1; n = 17 remitted; n = 14 depressed) and 24 age- and gender-ratio-matched healthy individuals (HC) viewed neutral, mild, and intense happy or sad emotional faces in two experiments. The FC was computed as linear and nonlinear dependence measures between amygdala and OFC time series. Effects of group, laterality, and emotion intensity upon amygdala-OFC FC and amygdala-OFC FC white matter fractional anisotropy (FA) relationships were examined. Results: The BD versus HC showed significantly greater right amygdala-OFC FC (p <= .001) in the sad experiment and significantly reduced bilateral amygdala-OFC FC (p = .007) in the happy experiment. Depressed but not remitted female BD versus female HC showed significantly greater left amygdala-OFC FC (p = .001) to all faces in the sad experiment and reduced bilateral amygdala-OFC FC to intense happy faces (p = .01). There was a significant nonlinear relationship (p = .001) between left amygdala-OFC FC to sad faces and FA in HC. In BD, antidepressants were associated with significantly reduced left amygdala-OFC FC to mild sad faces (p = .001). Conclusions: In BD, abnormally elevated right amygdala-OFC FC to sad stimuli might represent a trait vulnerability for depression, whereas abnormally elevated left amygdala-OFC FC to sad stimuli and abnormally reduced amygdala-OFC FC to intense happy stimuli might represent a depression state marker. Abnormal FC measures might normalize with antidepressant medications in BD. Nonlinear amygdala-OFC FC-FA relationships in BID and HC require further study.

Elevated left and reduced right orbitomedial prefrontal fractional anisotropy in adults with bipolar disorder revealed by tract-based spatial statistics

Context Diffusion tensor imaging (DTI) studies in adults with bipolar disorder (BD) indicate altered white matter (WM) in the orbitomedial prefrontal cortex (OMPFC), potentially underlying abnormal prefrontal corticolimbic connectivity and mood dysregulatioin in BD. Objective: To use tract-based spatial statistics (TBSS) to examine VVM skeleton (ie, the most compact whole-brain WM) in subjects with BD vs healthy control subjects. Design: Cross-sectional, case-control, whole-brain DTI using TBSS. Setting: University research institute. Participants: Fifty-six individuals, 31 having a DSM-IV diagnosis of BD type 1 (mean age, 35.9 years [age range, 24-52 years]) and 25 controls (mean age, 29.5 years [age range, 19-52 years]). Main Outcome Measures: Fractional anisotropy (FA) longitudinal and radial diffusivities in subjects with BD vs controls (covarying for age) and their relationships with clinical and demographic variables. Results: Subjects with BD vs controls had significantly greater FA (t > 3.0, P <=.05 corrected) in the left uncinate fasciculus (reduced radial diffusivity distally and increased longitudinal diffusivity centrally), left optic radiation (increased longitudinal diffusivity), and right anterothalamic radiation (no significant diffusivity change). Subjects with BD vs controls had significantly reduced FA (t > 3.0, P <=.05 corrected) in the right uncinate fasciculus (greater radial diffusivity). Among subjects with BD, significant negative correlations (P <.01) were found between age and FA in bilateral uncinate fasciculi and in the right anterothalamic radiation, as well as between medication load and FA in the left optic radiation. Decreased FA (P <.01) was observed in the left optic radiation and in the right anterothalamic radiation among subjects with BD taking vs those not taking mood stabilizers, as well as in the left optic radiation among depressed vs remitted subjects with BD. Subjects having BD with vs without lifetime alcohol or other drug abuse had significantly decreased FA in the left uncinate fasciculus. Conclusions: To our knowledge, this is the first study to use TBSS to examine WM in subjects with BD. Subjects with BD vs controls showed greater WM FA in the left OMPFC that diminished with age and with alcohol or other drug abuse, as well as reduced WM FA in the right OMPFC. Mood stabilizers and depressed episode reduced WM FA in left-sided sensory visual processing regions among subjects with BD. Abnormal right vs left asymmetry in FA in OMPFC WM among subjects with BD, likely reflecting increased proportions of left-sided longitudinally aligned and right-sided obliquely aligned myelinated fibers, may represent a biologic mechanism for mood dysregulation in BD.

Comparisons of the release of vasodilator substances from left and right cardiac chambers of the isolated perfused rabbit heart: Implications for intraventricular thrombus formation

Prostacyclin (PgI(2)) and endothelium-derived nitric oxide (EDNO) are produced by the arterial and venous endothelium. In addition to their vasodilator action on vascular smooth muscle, both act together to inhibit platelet aggregation and promote platelet disaggregation. EDNO also inhibits platelet adhesion to the endothelium. EDNO and PgI(2) have been shown to be released from the cultured endocardial cells. In this study, we examined the release of vasoactive substances from the intact endocardium by using isolated rabbit hearts perfused with physiological salt solution (95% O(2)/5% CO(2), T = 37 degrees C). The right and left cardiac chambers were perfused through separate constant-flow perfusion loops (physiological salt solution, 8 ml min(-1)). Effluent from left and right cardiac, separately, was bioassayed on canine coronary artery smooth muscle, which had been contracted with prostaglandin F(2 alpha_)(2 x 10(-6) M) and no change in tension was exhibit. However, addition of calcium ionophore A23187 (10(-6) M) to the cardiac chambers` perfusion line induced vasodilation of the bioassay coronary ring, 61.4 +/- 7.4% versus 70.49 +/- 6.1% of initial prostaglandin F(2 alpha) contraction for the left and right cardiac chambers perfusate, respectively (mean +/- SEM, n = 10, p > 0.05). Production of vasodilator was blocked totally in the left heart but, only partially blocked in the right heart by adding indomethacin (10(-5) M) to the perfusate, respectively, 95.2 +/- 2.2% versus 41.5 +/- 4.8% (mean +/- SEM, n = 10, p < 0.05). 6-Keto prostaglandin F(1 alpha), measured in the endocardial superfusion effluent was also higher for the left cardiac chambers than for the right at the time of stimulation with the A23187, respectively, 25385.88 +/- 5495 pg/ml (n = 8) versus 13,132.45 +/- 1839.82 pg/ml (n = 8), (p < 0.05). These results showed that cyclooxygenase pathway plays major role in generating vasoactive substances for the left cardiac chamber endocardium; while it is not the main pathway for the right ventricular endocardium at which EDNO and PgI(2) Could act together and potentiate their antithrombogenic activities in isolated perfused rabbit heart. This may be an explanation for the intraventricular thrombus mostly seen in left ventricle rather than in right ventricle as a complication of myocardial infarction. (C) 2009 Elsevier Inc. All rights reserved.

Heart Transplantation in Arrhythmogenic Right Ventricular Dysplasia: Case Reports

Objective. Arrhythmogenic right ventricular dysplasia (ARVD) is a myocardial disease of familiar, origin where the myocardium is replaced by fibrofatty tissue predominantly in the right ventricle. Herein we have presented the clinical courses of 4 patients with ARVD who underwent orthotopic heart transplantation. Patients and Methods. Among 358 adult patients undergoing heart transplantation, 4 (1.1%) displayed ARVD. The main indication for transplantation was the progression to heart failure associated with arrhythmias. All 4 patients displayed rapid, severe courses leading to heart failure with left ventricular involvement and uncontrolled arrhythmias. Results. In all cases the transplantation was performed using a bicaval technique with prophylactic tricuspid valve annuloplasty. One patient developed hyperacute rejection and infection, leading to death on the 7th day after surgery. The other 3 cases showed a good evolution with clinical remission of the symptoms. Pathological study of the explanted hearts confirmed the presence of the disease. Conclusions. ARVD is a serious cardiomyopathy that can develop malignant arrhythmias, severe ventricular dysfunction with right ventricular predominance, and sudden cardiac death. Orthotopic heart transplantation must always be considered in advanced cases of ARVD with malignant arrhythmias or refractory congestive heart failure with or without uncontrolled arrhythmias, because it is the only way to remit the symptoms and the disease.

rTMS treatment for depression in Parkinson`s disease increases BOLD responses in the left prefrontal cortex

The mechanisms underlying the effects of antidepressant treatment in patients with Parkinson`s disease (PD) are unclear. The neural changes after successful therapy investigated by neuroimaging methods can give insights into the mechanisms of action related to a specific treatment choice. To study the mechanisms of neural modulation of repetitive transcranial magnetic Stimulation (rTMS) and fluoxetine, 21 PD depressed patients were randomized into only two active treatment groups for 4 wk: active rTMS over left dorsolateral prefrontal cortex (DLPFC) (5 Hz rTMS; 120% motor threshold) with placebo pill and sham rTMS with fluoxetine 20mg/d. Event-related functional magnetic resonance imaging (fMRI) with emotional stimuli was performed before and after treatment - in two sessions (test and re-test) at each time-point. The two groups of treatment had a significant, similar mood improvement. After rTMS treatment, there were brain activity decreases in left fusiform gyrus, cerebellum and right DLPFC and brain activity increases in left DLPFC and anterior cingulate gyrus compared to baseline. In contrast, after fluoxetine treatment, there were brain activity increases in right premotor and right medial prefrontal cortex. There was a significant interaction effect between groups vs. time in the left medial prefrontal cortex, suggesting that the activity in this area changed differently in the two treatment groups. Our findings show that antidepressant effects of rTMS and fluoxetine in PD are associated with changes in different areas of the depression-related neural network.

Laparoscopic right hemihepatectomy for hepatolithiasis

Background Liver resection is the definitive treatment for unilateral hepatolithiasis [1]. Recently, laparoscopic major hepatectomias have become more common and are being performed in highly specialized centers [2-4]. However, few laparoscopic liver resections for hepatolithiasis have been reported. Chen et al. [5] reported two cases of laparoscopic left lobectomy for hepatolithiasis, but to our knowledge, right hepatectomy has never been reported to date. This video demonstrates technical aspects of a totally laparoscopic right hepatectomy in a patient with hepatolithiasis. Methods A 21-year-old woman with right-sided nonoriental primary intrahepatic stones [1] was referred for surgical treatment. The operation followed four distinct phases: liver mobilization, dissection of the right portal vein and right hepatic artery, extrahepatic dissection of the right hepatic vein, and parenchymal transection with harmonic shears and linear staplers for division of segment 5 and 8 branches of the middle hepatic vein. No Pringles` maneuver was used. In contrast to liver resection for other indications, the right bile duct was enlarged and filled with stones. It was divided during parenchymal transection and left open. After removal of the surgical specimen, the biliary tree was flushed with saline until stone clearance, under radioscopic surveillance, was complete. The right hepatic duct then was closed with running suture. Results The operative time was 240 min, and the estimated blood loss was 120 ml, with no blood transfusion. The hospital stay was 5 days. At this writing, the patient is well and asymptomatic 7 months after the procedure. Conclusion Laparoscopic liver resection is safe and feasible for patients with hepatolithiasis and should be considered for those suffering from intrahepatic stones.

Narrowed lumen of the right coronary artery in chronic chagasic patients is associated with ischemic lesions of segmental thinnings of ventricles

Thinning of myocardial segments, mainly at the apex and basal posterior region of left ventricle, are frequent lesions in chronic chagasic cardiopathy (CCC), but still without a well determined etiology. Previously we found severe myocardial microvascular dilatation that could cause ischemia in watershed regions. In this study we analyzed whether narrowness in epicardial coronary arteries in CCC might explain these thinned ventricular lesions. Two groups of dilated hearts with similar weights were compared: eleven hearts from patients with CCC versus four hearts from patients with dilated cardiomyopathy (IDCM). As normal controls we studied three non dilated normal weight hearts. There were no atherosclerotic plaques in the main branches of epicardial coronary arteries and cross-sectional luminal areas of proximal and distal segments were histologically measured. It was found that CCC hearts presented a lower mean luminal area in the right coronary artery (RCA) branch than IDCM, in proximal (4.3 +/- 1.4 vs 6.6 +/- 2.0 mm(2); p = 0.02) and in distal (1.6 +/- 1.0 vs 3.4 +/- 0.9 mm(2); p = 0.01) segments, with no statistical differences with normal hearts (2.7 +/- 1.3 and 1.5 +/- 0.3 mm(2)) in proximal (p = 0.2) and distal (p = 0.11) sections. In conclusion thinning of ventricular wall in CCC patients seems to be ischemic lesions in the peripheral territory irrigated by the right coronary artery, possibly due to a steal phenomenon by the left coronary, induced by micro vessels dilatation.

Validation of a Cutoff Value on Echo Doppler Analysis to Replace Right Heart Catheterization During Pulmonary Hypertension Evaluation in Heart Transplant Candidates

Background. Heart transplantation (OHT) has traditionally been contraindicated in the presence of severe pulmonary hypertension (PH), as detected by right heart catheterization. Noninvasive methods are still not reliably accurate to make this evaluation. Objectives. Determine the efficacy of echo Doppler analysis for the diagnosis of severe PH. Methods. One hundred thirty patients (mean age = 42 +/- 15 years, 82 men) showed severe left ventricular dysfunction (mean ejection fraction = 29 +/- 12%; functional class III-IV). We excluded patients with atrial fibrillation, heart failure secondary to congenital disease, and valvulopathy. The pulmonary parameters defined as severe PH were: systolic pulmonary artery pressure (sPAP) >= 60 mm Hg; a mean transpulmonary gradient >= 15; or pulmonary vascular resistance >= 5 Wood units. Patients underwent a right heart catheterization using a Swan-Ganz catheter to measure hemodynamic parameters and to noninvasively estimate right-sided pressures from spectral Doppler recordings of tricuspid regurgitation velocity (right ventricular systolic pressure [RVsP]). A Pearson correlation of sPAP was obtained with RVsP by; the sensitivity of RVsP for the diagnosis of PH was determined by a receiver operating characteristic (ROC) curve. Results. A good correlation between sPAP and RVsP was obtained by Pearson correlation analysis (r = 0.64; 95% confidence interval [CI] 0.50-0.75; P < .001). The ROC curve analysis showed a sensitivity of 100%, a specificity of 37.2%, (95% CI 0.69-0.83, P < .0001) of a RVsP < 45 mm Hg (cutoff) on the exclusion of severe PH. Conclusions. The cutoff of RVsP < 45 mm Hg, on noninvasive echo Doppler evaluation of PH is an efficient method to replace invasive heart catheterization in OHT candidates.

Cavopulmonary anastomosis improves left ventricular assist device support in acute biventricular failure

Objective: Right ventricular failure during left ventricular assist device (WAD) support can result in severe hemodynamic compromise with high mortality. This study investigated the acute effects of cavopulmonary anastomosis on right ventricular loading and WAD performance in a model of severe biventricular failure. Methods: LVAD support was performed by means of centrifugal pump implantation in 14 anesthetized dogs (20-30 kg) with severe biventricular failure obtained by ventricular fibrillation induction. Animals were randomized to be submitted to classical cavopulmonary anastomosis (Glenn shunt) or to control group and were maintained under WAD support for 2 h. Left and right atrial, right ventricular and systemic pressures were monitored, white total pulmonary flow was simultaneously recorded by transonic flowmeters located on the superior vena cava and pulmonary trunk. Blood gas and venous lactate determinations were also obtained. Results: Ventricular fibrillation maintenance resulted in acute WAD performance impairment after 90 min in the control group, while animals with Glenn circuit maintained normal WAD pump flow (55 +/- 13 ml kg(-1) min(-1) vs 21 +/- 4 ml kg(-1) min(-1), p < 0.001) and better peripheral perfusion (blood lactate of 29 +/- 10 pg/ml vs 46 +/- 9 pg/ml, p < 0.001). Left and right atrial pressures did not change significantly, while right ventricular pressure was tower in animals with Glenn circuit (13 +/- 3 mmHg vs 22 +/- 8 mmHg, p = 0.005). Right ventricular unloading with Glenn shunt also resulted in superior total pulmonary flow (59 +/- 13 ml kg(-1) min(-1) vs 17 +/- 3 ml kg(-1) min(-1), p < 0.001). Conclusion: The concomitant use of cavopulmonary anastomosis during LVAD support in a model of severe biventricular failure limited right ventricular overloading and resulted in better hemodynamic performance. (C) 2008 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.