Tuberculous hepatitis in renal transplant recipients following alemtuzumab induction therapy

Mycobacterium tuberculosis infection is one of many opportunistic infections in renal transplant recipients, arising either from reactivation of latent infection or de novo infection, occasionally donor derived. M. tuberculosis hepatitis has never been reported in patients who have received alemtuzumab as part of their renal transplant management. We describe 2 patients who underwent deceased‐donor renal transplantation following alemtuzumab induction therapy and presented with a febrile syndrome, subsequently diagnosed as tuberculous hepatitis, one with disseminated disease. Both responded well to treatment without significant side effects, resulting in excellent graft function. The importance of chemoprophylaxis should be emphasized to minimize the risk of developing active tuberculosis in patients with latent tuberculosis infection undergoing solid organ transplantation.     

Chronic inhibition of PPAR-γ signaling induces endothelial dysfunction in the juvenile lamb

We have recently shown that the development of endothelial dysfunction in lambs with increased pulmonary blood flow (PBF) correlates with a decrease in peroxisome proliferator activated receptor-γ (PPAR-γ) signaling. Thus, in this study we determined if the loss of PPAR-γ signaling is necessary and sufficient to induce endothelial dysfunction by exposing lambs with normal PBF to the PPAR-γ antagonist, GW9662. Two-weeks of exposure to GW9662 significantly decreased both PPAR-γ protein and activity. In addition, although eNOS protein and nitric oxide metabolites (NO_x) were significantly increased, endothelial dependent pulmonary vasodilation in response to acetylcholine was attenuated, indicative of endothelial dysfunction. To elucidate whether downstream mediators of vasodilation were impaired we examined soluble guanylate cyclase (sGC)-α and β subunit protein, cGMP levels, and phosphodiesterase 5 (PDE5) protein and activity, but we found no significant changes. However, we found that peroxynitrite levels were significantly increased in GW9662-treated lambs and this correlated with a significant increase in protein kinase G-1α (PKG-1α) nitration and a reduction in PKG activity. Peroxynitrite is formed by the interaction of NO with superoxide and we found that there was a significant increase in superoxide generation in GW9662-treated lambs. Further, we identified dysfunctional mitochondria as the primary source of the increased superoxide. Finally, we found that the mitochondrial dysfunction was due to a disruption in carnitine metabolism. We conclude that loss of PPAR-γ signaling is sufficient to induce endothelial dysfunction confirming its important role in maintaining a healthy vasculature.     

Palliative stent placement in vertical vein in a 1.4 kg infant with obstructed supracardiac total anomalous pulmonary venous connection

Temporary relief of obstructed total anomalous pulmonary venous connection (TAPVC) may stabilize the preoperative clinical status. We report a 1.4 kg infant with obstructed supracardiac TAPVC to right sided superior vena cava, double outlet right ventricle, pulmonary atresia, major aortopulmonary collateral arteries, and atrioventricular septal defect. A palliative percutaneous stent was successfully placed and resulted in immediate clinical improvement. We performed a review of literature regarding interventional procedures for relief of obstructed TAPVC and found 17 cases including stent placement (13), balloon angioplasty (3), and Hybrid procedure (1). We conclude that temporary stent placement in obstructed TAPVC is feasible and efficacious in relieving pulmonary venous obstruction. The procedure can lead to subsequent surgical repair in a more favorable clinical status and has special significance in the low birth weight infant. © 2012 Wiley Periodicals, Inc.     

Identification of apnea during respiratory monitoring using support vector machine classifier: a pilot study

To determine the use of photoplethysmography (PPG) as a reliable marker for identifying respiratory apnea based on time–frequency features with support vector machine (SVM) classifier. The PPG signals were acquired from 40 healthy subjects with the help of a simple, non-invasive experimental setup under normal and induced apnea conditions. Artifact free segments were selected and baseline and amplitude variabilities were derived from each recording. Frequency spectrum analysis was then applied to study the power distribution in the low frequency (0.04–0.15 Hz) and high frequency (0.15–0.40 Hz) bands as a result of respiratory pattern changes. Support vector machine (SVM) learning algorithm was used to distinguish between the normal and apnea waveforms using different time–frequency features. The algorithm was trained and tested (780 and 500 samples respectively) and all the simulations were carried out using linear kernel function. Classification accuracy of 97.22 % was obtained for the combination of power ratio and reflection index features using SVM classifier. The pilot study indicates that PPG can be used as a cost effective diagnostic tool for detecting respiratory apnea using a simple, robust and non-invasive experimental setup. The ease of application and conclusive results has proved that such a system can be further developed for use in real-time monitoring under critical care conditions.