Melatonin reduces oxidative stress and improves vascular function in pulmonary hypertensive newborn sheep

Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.     

Riesgo de recurrencia tras retirada de la anticoagulación en pacientes con enfermedad tromboembólica venosa no provocada: validación externa del nomograma de Viena y del modelo predictivo DASH

IntroductionScales for predicting venous thromboembolism (VTE) recurrence are useful for deciding the duration of the anticoagulant treatment. Although there are several scales, the most appropriate for our setting has not been identified. For this reason, we aimed to validate the DASH prediction score and the Vienna nomogram at 12 months.MethodsThis was a retrospective study of unselected consecutive VTE patients seen between 2006 and 2014. We compared the ability of the DASH score and the Vienna nomogram to predict recurrences of VTE. The validation was performed by stratifying patients as low-risk or high-risk, according to each scale (discrimination) and comparing the observed recurrence with the expected rate (calibration).ResultsOf 353 patients evaluated, 195 were analyzed, with an average age of 53.5 ± 19 years. There were 21 recurrences in 1 year (10.8%, 95% CI: 6.8%-16%). According to the DASH score, 42% were classified as low risk, and the rate of VTE recurrence in this group was 4.9% (95% CI: 1.3%-12%) vs. the high-risk group that was 15% (95% CI: 9%-23%) (p <.05). According to the Vienna nomogram, 30% were classified as low risk, and the rate of VTE recurrence in the low risk group vs. the high risk group was 4.2% (95% CI:0.5%-14%) vs. 16.2% (95% CI: 9.9%-24.4%) (p <.05).ConclusionsOur study validates the DASH score and the Vienna nomogram in our population. The DASH prediction score may be the most advisable, both because of its simplicity and its ability to identify more low-risk patients than the Vienna nomogram (42% vs. 30%).     

HCG--A new kid on the block in prematurity prevention.

Human chorionic gonadotropin (HCG) is a molecule with multiple endocrine, paracrine, and immunoregulatory actions. Its importance for the enhancement of fertility, successful implantation, and survival of the conceptus in early gestation is recognized. However, studies conducted worldwide in recent years indicate that HCG may also play a significant role in maintaining pregnancy well after the first trimester. Emerging evidence suggests that different biomolecular and physiologic effects of HCG are concordantly directed toward inhibition of myometrial contractility to maintain pregnancy. These studies have prompted preliminary animal and human testing of HCG for the prevention of preterm birth. This article reviews the current knowledge as well as the future perspectives on HCG as a useful new tool in prematurity prevention.     

A case of unilateral opercular syndrome associated with a subcortical lesion

Summary A patient who developed a unilateral opercular syndrome following a cerebrovascular accident is described. Computed tomography showed that the lesion did not affect the opercular cortex, but involved deep white matter and the head of the caudate nucleus of the left hemisphere. Persistent hypophonia and transient aphasia were associated. Comparison with previous cases is discussed.     

Liver Transplantation Across Rh Blood Group Barriers Increases the Risk of Biliary Complications

Background Cold ischemia time and the presence of postoperative hepatic arterial thrombosis have been associated with biliary complications (BC) after liver transplantation. An ABO-incompatible blood group has also been suggested as a factor for predisposal towards BC. However, the influence of Rh nonidentity has not been studied previously. Materials Three hundred fifty six liver transplants were performed from 1995 to 2000 at our hospital. BC incidence and risk factors were studied in 345 patients. Results Seventy patients (20%) presented BC after liver transplantation. Bile leakage (24/45%) and stenotic anastomosis (21/30%) were the most frequent complications. Presence of BC in Rh-nonidentical graft–host cases (23/76, 30%) was higher than in Rh-identical grafts (47/269, 17%) (P = 0.01). BC was also more frequent in grafts with arterial thrombosis (9/25, 36% vs 60/319, 19%; P = 0.03) and grafts with cold ischemia time longer than 430 min (26/174, 15% vs 44/171, 26%; P = 0.01). Multivariate logistic regression confirmed that Rh graft–host nonidentical blood groups [RR = 2(1.1–3.6); P = 0.02], arterial thrombosis [RR = 2.6(1.1–6.4); P = 0.02] and cold ischemia time longer than 430 min [RR = 1.8(1–3.2); P = 0.02] were risk factors for presenting BC. Conclusion Liver transplantation using Rh graft–host nonidentical blood groups leads to a greater incidence of BC.