A stochastic frontier production function with flexible risk properties

This paper considers a stochastic frontier production function which has additive, heteroscedastic error structure. The model allows for negative or positive marginal production risks of inputs, as originally proposed by Just and Pope (1978). The technical efficiencies of individual firms in the sample are a function of the levels of the input variables in the stochastic frontier, in addition to the technical inefficiency effects. These are two features of the model which are not exhibited by the commonly used stochastic frontiers with multiplicative error structures, An empirical application is presented using cross-sectional data on Ethiopian peasant farmers. The null hypothesis of no technical inefficiencies of production among these farmers is accepted. Further, the flexible risk models do not fit the data on peasant farmers as well as the traditional stochastic frontier model with multiplicative error structure.

Propranolol reduces variceal pressure and wall tension in schistosomiasis presinusoidal portal hypertension

Background and Aim: Although prophylaxis with beta-blockers has been shown to decrease variceal pressure and wall tension in cirrhotic patients, this has not been demonstrated in non-cirrhotic portal hypertension caused by Schistosoma mansoni infection. Methods: Thirteen patients without history of previous gastrointestinal bleeding were included. All of them had high-risk esophageal varices at endoscopy. An endoscopic gauge and a high-frequency endoscopic ultrasonography miniprobe were used to assess transmural variceal pressure and wall tension before and after achieving beta-blockade with propranolol. Results: Baseline variceal pressure decreased from 13.3 +/- 3.5 to 8.2 +/- 2.0 mmHg (P < 0.0001) and wall tension from 500.2 +/- 279.8 to 274.0 +/- 108.3 mg.mm-1. The overall effect of propranolol on decreasing variceal pressure and wall tension expressed in percentage change in relation to baseline values was 35.7 +/- 18.4% and 35.9 +/- 26.7%, respectively (P = 0.9993). Conclusion: Propranolol significantly reduced variceal pressure and wall tension in schistosomiasis.

Long-term follow-up of children with extrahepatic portal vein obstruction: impact of an endoscopic sclerotherapy program on bleeding episodes, hepatic function, hypersplenism, and mortality

Background: Endoscopic sclerotherapy (ES) has been the standard treatment for children with idiopathic extrahepatic portal vein obstruction (EHPVO). Portosystemic shunts are indicated when variceal bleeding cannot be controlled by ES. Recently, mesenteric left portal vein bypass was indicated as a surgical intervention and preventative measure for hepatic dysfunction in children with long-term EHPVO. Nevertheless, there is a lack Of published data confirming the extent of hepatic dysfunction, hypersplenism, and physical development in children with long-term follow-up. Method: We retrospectively verified the long-term outcomes in 82 children with EHPVO treated with ES protocol, focusing on mortality, control of bleeding, hypersplenism, and consequent hepatic dysfunction. Results: Of the children, 56% were free from bleeding after the initiation of ES. The most frequent cause of rebleeding was gastric varices (30%). Four patients had recurrent bleeding from esophageal varices (4.6%). Four patients underwent surgery as a consequence of uncontrolled gastric varices. There were no deaths. Most patients showed good physical development. We observed a mild but statistically significant drop in factor V motion, as well as leukocyte and platelet count. Conclusion: Endoscopic sclerotherapy is an efficient treatment for children with EHPVO. The incidence of rebleeding is low, and there was no mortality. Children develop mild liver dysfunction and hypersplenism with long-term follow-up. Only a few patients manifest symptoms of hypersplenism, portal biliopathy, or liver dysfunction before adolescence. (C) 2009 Elsevier Inc. All rights reserved.

Long-term results of the percutaneous transhepatic venoplasty of portal vein stenoses after pediatric liver transplantation

This paper has the objective to evaluate retrospectively the long-term results of transhepatic treatment of PV stenoses after pediatric LT. During an eight-yr period, 15 children with PV stenoses underwent PTA with balloon dilation or stent placement in case of PTA failure after LT. Patients` body weights ranged from 9.3 to 46 kg (mean, 15.5 kg). PV patency was evaluated in the balloon dilation and in the stent placement groups. Technical and clinical successes were achieved in all cases with no complication. Eleven patients (11/15; 73.3%) were successfully treated by single balloon dilation. Four patients (4/15; 26.7%) needed stent placement. One patient was submitted to stent placement during the same procedure because of PTA failure. The other three developed clinical signs of portal hypertension because of PV restenoses two, eight, and twenty-eight months after the first PTA. They had to be submitted to a new procedure with stent placement. The follow-up time ranged from 3 to 8.1 yr (mean, 6.3 yr). In conclusion, transhepatic treatment of PV stenoses after pediatric LT with balloon dilation or stent placement demonstrated to be a safe and effective treatment that results in long-term patency.

Aripiprazole for Patients with Schizophrenia and Schizoaffective Disorder: An Open-Label, Randomized, Study Versus Haloperidol

Introduction: Aripiprazole, a dopamine D(2) receptor partial agonist, has also partial agonist activity at serotonin (5-HT)(1A) receptors and antagonist activity at 5-HT(2A) receptors. Methods: In this 8-week, multicenter, randomized, parallel-group, open-label, flexible-dose study, patients diagnosed with schizophrenia or schizoaffective disorder were randomized to aripiprazole 15-30 mg/day or haloperidol 10-15 mg/day. Results: Patients treated with both aripiprazole and haloperidol improved from baseline in Positive and Negative Syndrome Scale total, positive, and negative scores as well as in Clinical Global Impressions scores (all P<.001). At the end of the study, the percentage of patients classified as responders-according to >= 40% reduction in the Positive and Negative Syndrome Scale negative subscale score-was significantly higher in the aripiprazole group (20%) than in the haloperidol group (0%) (P<.05). Additionally, a higher number of patients receiving haloperidol required more anticholinergic medications (P<.001) than aripiprazole-treated patients, whereas more aripiprazole (45.5%) than haloperidol-treated patients (12.9%) required benzodiazepines (P=.002). At endpoint, rates of preference of medication were higher in the aripiprazole group (63.2%) than in the haloperidol group (21.7%), as expressed by patients and caregivers (P=.001). Conclusion: Aripiprazole and haloperidol had similar efficacy in terms of reduction of overall psychopathology. Although aripiprazole has been demonstrated to be superior concerning negative symptoms and in terms of tolerability (extrapyramidal symptoms) and preferred by patients and caregivers than haloperidol, significantly more aripiprazole-treated patients required benzodiazepines.

Effects of the administration of pentoxifylline and prednisolone on the evolution of portal fibrogenesis secondary to biliary obstruction-an experimental study in growing animals

Background: Many chronic liver diseases lead to progressive hepatic fibrosis, a condition that can ultimately result in loss of organ function and severe portal hypertension necessitating hepatic transplantation. Within the last few decades, studies have been conducted to demonstrate the possibility of drug modulation of hepatic fibrogenesis. Regarding biliary obstruction, it has been suggested that administration of corticosteroids could promote better late outcomes for children with biliary atresia submitted to Kasai`s portoenterostomy. Models used to test potential antifibrogenic drugs such as pentoxifylline (PTX) have not included growing animals. Methods: In this experimental study, 119 young rats (21st or 22nd days) were submitted to laparotomy and common bile duct ligation (CBDL) or to sham surgery (SHAM). Animals were allocated into 5 groups, according to surgical procedure, and administered the following solutions: (1) CBDL + distilled water, (2) SHAM + distilled water, (3) CBDL + PTX, (4) CBDL + prednisolone (PRED), and (5) CBDL + PTX + PRED (PTX + PRED). Each group was further divided into 2 subgroups according to the length of the experiment (15 or 30 days). At the end of the defined period, animals were weighed, and a hepatic fragment was collected from each one for analyses. Results: The PTX animals exhibited increased weight gain compared to animals in the PRED or PTX + PRED groups. Animals from the 3 therapeutic groups (PTX, PRED, and PTX + PRED) showed diminished collagen-filled area in portal spaces. Total portal space area was increased in the PTX group. Conclusions: Hepatic fibrosis induced by bile duct ligation in young rats could be modulated by pharmacologic interventions. Administration of PTX or PRED, or the combination of both, resulted in diminished collagen-filled areas in portal spaces. (C) 2009 Elsevier Inc. All rights reserved.

Rex Shunt for Acute Portal Vein Thrombosis After Pediatric Liver Transplantation in Children With Biliary Atresia

Background/Purpose. Posttransplantation portal vein thrombosis (PVT) can have severe health consequences, and portal hypertension and other consequences of the long-term privation of portal inflow to the graft may be hazardous, especially in young children. The Rex shunt has been used successfully to treat PVT patients since 1998. In 2007, we started to perform this surgery in patients with idiopathic PVT and late posttransplantation PVT. Herein we have reported our experience with this technique in acute posttransplantation PVT. Methods. Three patients of ages 12, 15, and 18 months underwent cadaveric (n = 1) or living donor (n = 2) orthotopic liver transplantation (OLT). All patients had biliary atresia with portal vein hypoplasia; they developed acute PVT on the first postoperative day. They underwent a mesenteric-portal surgical shunt (Rex shunt) using a left internal jugular vein autograft (n = 2) or cadaveric iliac vein graft (n = 1) on the first postoperative day. Results. The 8-month follow-up has confirmed shunt patency by postoperative Doppler ultrasound. There have been no biliary complications to date. Conclusions. The mesenteric-portal shunt (Rex shunt) using an autograft of the left internal jugular or a cadaveric vein graft should be considered for children with acute PVT after OLT. These children usually have small portal veins; reanastomosis is often unsuccessful. In addition, this technique has the advantage to avoid manipulation of the hepatic hilum and biliary anastomosis. Although this study was based on a limited experience, we concluded that this technique is feasible, with great benefits to and low risks for these patients.

Absence of bifurcation of the portal vein

Absence of the horizontal segment of the left portal vein (PV) or absence of bifurcation of the portal vein (ABPV) is extremely rare anomaly. The aim of this study was to study the extra-hepatic PV demonstrating the importance of its careful assessment for the purpose of split-liver transplantation. Human cadaver livers (n = 60) were obtained from routine autopsies. The cutting plane of the liver consisted of a longitudinal section made immediately on the left of the supra-hepatic inferior vena cava through the gallbladder bed preserving the arterial, portal and biliary branches in order to obtain two viable grafts (right lobe-segments V, VI, VII, and VIII and left lobe-segments II, III, and IV) as defined by the main portal scissure. The PV was dissected out and recorded for application of the liver splitting. The PV trunk has been divided into right and left branch in 50 (83.3%) cases. A trifurcation of the PV was found in 9 (15.2%) cases, 3 (5%) was a right anterior segmental PV arising from the left PV and 6 (10%) a right posterior segmental PV arising from the main PV. ABPV occurred in 1 (1.6%) case. Absence of bifurcation of the portal vein is a rare anatomic variation, the surgeon must be cautious and aware of the existence of this exceptional PV anomaly either pre or intra-operatively for the purpose of hepatectomies or even split-liver transplantation.

Rex Shunt for the Treatment of Portal Vein Thrombosis After Pediatric Liver Transplantation: A Case Report

Background and Purpose. Late portal vein thrombosis (PVT) can be extremely well tolerated, although portal hypertension and other consequences of the long-term deprivation of portal inflow to the graft may be hazardous, especially in young children. Recently, the ""Rex shunt"" has been used successfully to treat these patients. We now report the initial experience with this novel technique. Methods. A 3-year-old girl with PVT at 7 months after whole organ cadaveric liver transplant displayed portal hypertension with an episode of gastrointestinal bleeding, requiring a mesenteric-portal surgical shunt (""Rex shunt"") using a left internal jugular vein autograft. Results. Upon current follow-up of 6 months, postoperative Doppler ultrasound confirmed shunt patency. Endoscopic status was significantly improved after surgery with resolution of portal hypertension. There was no recurrence of bleeding. Conclusions. The mesenteric-portal shunt (""Rex shunt""), using a left internal jugular vein autograft, should be considered for children with late PVT after liver transplantation. Although this is an initial experience, we may conclude that this technique is feasible, with great potential benefits and low risks for these patients.

Initial hepatosplanchnic blood flow distribution and oxygen metabolism in experimental model of hypotensive brain death

Background: Organs from the so-called marginal donors have been used with a significant higher risk of primary non function than organs retrieved from the optimal donors. We investigated the early metabolic changes and blood flow redistribution in splanchnic territory in an experimental model that mimics marginal brain-dead (BD) donor. Material/Methods: Ten dogs (21.3 +/- 0.9 kg), were subjected to a brain death protocol induced by subdural balloon inflation and observed for 30 min thereafter without ally additional interventions. Mean arterial and intracranial pressures, heart rate, cardiac output (CO), portal vein and hepatic artery blood flows (PVBF and HABF, ultrasonic flowprobe), and O(2)-derived variables were evaluated. Results: An increase in arterial pressure, CO, PVBF and HABF was observed after BD induction. At the end, an intense hypotension with normalization in CO (3.0 +/- 0.2 VS. 2.8 +/- 2.8 L/min) and PVBF (687 +/- 114 vs. 623 +/- 130 ml/min) was observed, whereas HABF (277 33 vs. 134 28 ml/min, p<0.005) remained lower than baseline values. Conclusions: Despite severe hypotension induced by sudden increase of intracranial pressure, the systemic and splanchnic blood flows were partially preserved without signs of severe hypoperfusion (i.e. hyperlactatemia). Additionally, the HABF was mostly negatively affected in this model of marginal BD donor. Our data suggest that not only the cardiac output, but the intrinsic hepatic microcirculatory mechanism plays a role in the hepatic blood flow control after BD.

CONGENITAL CLUBFOOT

The clubfoot is one of the most common congenital deformities affecting the lower limbs, it still presents controversial aspects regarding etiology and treatment. In spite of its relatively high frequency, the treatment is still challenging, since the long-term aim is achieving an everlasting flexible, plantigrade, pain-free and totally functional foot. The Ponseti method has gained attention and popularity because of its satisfactory results and surgery avoidance. Presently, surgical treatment is indicated only after failure of conservative methods, avoiding extensive soft-tissue release, but performing localized corrections of the deformities, a technique also know as ""a la carte"" release. The future perspective is based on the knowledge about long-term results and new understanding of the clubfoot etiology, especially in the genetic field, which may eventually be helpful for prognostic and treatment. Level of Evidence: Level II, systematic review.

Can the Insulin Sensitivity Index (ISI) in Association with Insulin-like Growth Factor Binding Protein-1 Identify Insulin Resistance Early in Overweight Children?

Association between insulin resistance (IR) and non-alcoholic fatty liver disease (NAFLD) has been reported. This prompted us to evaluate the power of the insulin sensitivity index (ISI) in association with IGFBP-1 to identify IR early in obese children/adolescents. OGTT was performed in 34 obese/overweight children/adolescents. Glucose, insulin and IGFBP-1 were measured in serum samples and ISI was calculated. Considering the presence of three or more risk factors for IR as a criterion for IR, ISI <4.6 showed 87.5% sensitivity and 94.5% specificity in diagnosing IR. IGFBP-1 was lower in the group with ISI <4.6 (p <0.01). In this group, three patients had higher than expected IGFBP-1, suggesting hepatic IR, while three patients with ISI >4.6 showed very low IGFBP-1 levels. Conclusion: ISI <4.6 is a good indicator of early peripheral IR and, associated with IGFBP-1, can identify increased risk of hepatic IR. Low IGFBP-1 levels among non-IR children may indicate increased portal insulin levels.

Hepatoportal Sclerosis and Extrahepatic Portal Venous Obstruction Associated with Anti-phospholipid Antibody Syndrome in Child

We report a 2-year-old child with extrahepatic portal venous obstruction, hepatoportal sclerosis and pulmonary thromboembolism whose sole hypercoagulability factor was the presence of anti-phospholipid antibodies.

Atm knock-in mice harboring an in-frame deletion corresponding to the human ATM 7636del9 common mutation exhibit a variant phenotype

ATM, the gene mutated in the human immunodeficiency disorder ataxia-telangiectasia (A-T), plays a central role in recognizing ionizing radiation damage in DNA and in controlling several cell cycle checkpoints. We describe here a murine model in which a nine-nucleotide in-frame deletion has been introduced into the Atm gene by homologous recombination followed by removal of the selectable marker cassette by Cre-loxP site-specific, recombination-mediated excision. This mouse, Abm-Delta SRI, was designed as a model of one of the most common deletion mutations (7636de19) found in A-T patients. The murine Atm deletion results in the loss of three amino acid residues (SRI; 2556-2558) but produces near full-length detectable Atm protein that lacks protein kinase activity. Radiosensitivity was observed in Atm-Delta SRI mice, whereas the immunological profile of these mice showed greater heterogeneity of T-cell subsets than observed in Atm(-/-) mice. The life span of Atm-Delta SRI mice was significantly longer than that of Atm(-/-) mice when maintained under nonspecific pathogen-free conditions. This can be accounted for by a lower incidence of thymic lymphomas in Atm-Delta SRI mice up to 40 weeks, after which time the animals died of other causes. The thymic lymphomas in Atm-Delta SRI mice were characterized by extensive apoptosis, which appears to be attributable to an increased number of cells expressing Fas ligand. A variety of other tumors including B-cell lymphomas, sarcomas, and carcinomas not seen in Atm(-/-) mice were observed in older Atm-Delta SRI animals. Thus, expression of mutant protein in Atm-Delta SRI knock-in mice gives rise to a discernibly different phenotype to Atm(-/-) mice, which may account for the heterogeneity seen in A-T patients with different mutations.