Pregnancy after liver transplantation: a case series and review of the literature

Objective: To evaluate maternal and perinatal outcomes in pregnant women after liver transplantation with a case series and literature systematic review. Methods: This was a single-center case-series study performed at University of Naples Federico II. All consecutive women with liver transplantation who reported pregnancy at our institution were included in a dedicated database. In addition, a systematic literature review was performed, including case series, population-based studies, and national registries, including maternal and perinatal outcomes of pregnant women with liver transplant. Studies with fewer than 10 cases and surveys were excluded. The primary outcome was perinatal death, defined as either stillbirth (defined as intrauterine fetal death after 20 weeks of gestation) or neonatal death (death of a live-born infant within the first 28 d of life). Results: During the study period, two women who underwent liver transplantation had a pregnancy in our Institution. Both of them underwent liver transplantation for biliary atresia at 1 year of age. One of them received cyclosporin as immunosuppressive regime during pregnancy, while the other one received tacrolimus. Both of them had a pregnancy with no major complications and delivered by cesarean section at term a baby with normal weight. One of them developed thrombocytopenia. Seventeen articles were included in this systematic review. Preterm birth at less than 37 weeks of gestations occurred in 279 women (33.6%). One-hundred women (14.9%) experienced preeclampsia, and 206 women (49.2%) delivered by cesarean delivery. Graft rejection related to pregnancy occurred in 73 women (8.3%). 117 women (12.9%) experienced miscarriage, and 22 (2.3%) IUFD. Fifty-two women (9.52%) underwent elective I-TOP. 195 fetuses (33.4%) were LBW. Eight neonatal deaths were recorded (1.3%). Conclusion: The maternal and perinatal outcome is usually favorable, but with an increased risk of preeclampsia, preterm birth, and perinatal morbidity and mortality. However, appropriate counseling about risks and complications is essential but women shouldn't be advised against pregnancy

A New Estimation Algorithm for Interval Censored Data from Repairable Systems

For a minimally repaired system, whose failure process is described by a non-homogeneous Poisson process (NHPP), the classical maximum likelihood estimation procedures cannot be used when the system failures are hidden and detected only at inspection epochs. By assuming that the failure process follows a NHPP with power law intensity function, the Expectation-Maximization (EM) algorithm was recently proposed to estimate the model parameters and a procedure to test the presence of trend in the real failure data of some components of identical medical infusion pumps was discussed. However, the EM algorithm suffers in this application from some limitations due to its complexity and the large computational time required for convergence. This paper proposes a new estimation algorithm which is still iterative but, unlike the EM algorithm, is not based on the expectation of the log-likelihood function with respect to the conditional distribution of the unobserved data, but rather on the expectation of the conditioning variables, that is, of the unknown age of the system at the previous failure. This approach allows one to specify a simpler and much faster estimation procedure. A comparison between the proposed and the EM algorithms shows that the former performs as well as the latter, while requiring a drastically reduced computational burden. In addition, the proposed scheme can be applied to other intensity functions, such as the log-linear and the 2-parameter logarithmic functions. As a result, the test hypothesis of no trend in one of the analyzed datasets, which can not be rejected under the power law intensity function, is instead rejected under the alternative hypothesis of a log-linear intensity function

A random-effects model for long-term degradation analysis of solid oxide fuel cells

Solid oxide fuel cells (SOFCs) are electrochemical devices converting the chemical energy into electricity with high efficiency and low pollutant emissions. Tough very promising, this technology is still in a developing phase, and degradation at the cell/stack level with operating time is still an issue of major concern. Methods to directly observe degradation modes and to measure their evolution over time are difficult to implement, and indirect performance indicators are adopted, typically related to voltage measurements in long-term tests. In order to describe long-term degradation tests, three components of the voltage measurements should be modelled: the smooth decay of voltage over time for each single unit; the variability of voltage decay among units; and the high-frequency small fluctuations of voltage due to experimental noise and lack of fit. In this paper, we propose an empirical random-effects regression model of polynomial type enabling to evaluate separately these three types of variability. Point and interval estimates are also derived for some performance measures, such as the mean voltage, the prediction of cell voltage, the reliability function and the cell-to-cell variability in SOFC stacks. Finally, the proposed methodology is applied to two real case-studies of long-term degradation tests of SOFC stacks

Semi-Markov Models for Performance Evaluation of Telecommunication Networks in the Presence of Failures

Planning and deployment of next generation telecommunication networks based on the Third Generation Partnership Project IP Multimedia Subsystem (IMS) must take into account the occurrence of random failures causing performance degradations, in order to assess and maintain the Quality of Service offered by telecommunication service providers to their subscribers. In particular, core network signalling servers of IMS can be modelled as repairable multi-state elements where server states correspond to different performance levels. In this paper, we evaluate IMS signalling network performance in terms of the number of sessions handled by the network per time unit, by adopting a semi-Markov model for the IMS servers, which allows as well for non-exponential probability distributions of sojourn times, as often observed in practical network scenarios. Furthermore, a redundancy optimisation problem is solved in an IMS-based realistic scenario, to the aim of minimizing the deployment cost of a telecommunication network with a given availability requirement

Parachute emergency landing simulation and enhanced composite material characterization for General Aviation aircraft

General Aviation (GA) aircraft crashworthiness of the vehicle when it hits the ground after the parachute deployment is an important issue. The current dynamic emergency landing regulation (CS 23.562) defines the maximum human tolerant accelerations under both vertical and horizontal directions. This article aims to compare two different aircraft configurations: metal low-wing and composite high-wing ones. Both are two-seats and single-engine GA aircraft. The purpose of the analysis is to check whether the seats and restraint systems met human injury tolerance standards and to determine the possible impact on passengers in the cabin space due to shock loads. Finite element analysis of the fuselage sections for both configurations is performed using the commercial LS-Dyna solver. An extensive campaign of experimental tests has been performed on the composite samples for tuning and validating the model and to find the transition from an undamaged up to totally collapsed sample. The material of the composite fuselage has been characterized through experimental tests. The adopted material model has been refined to match with the performed experimental analysis, allowing high-fidelity modeling. A parametric analysis has been performed to determine the optimal impact angle in terms of lumbar injuries and loads transmitted by the seat belt due to aircraft contact with the ground, thereby increasing the level of safety. The investigations carried out may be an important indicator of the design of the parachute system

seemingly unrelated regression equations for developing a pavement performance model

The paper presents a joint analysis of some pavement performance indicators based on a system of seemingly unrelated regression equations (SURE) which allows to handle correlated error terms. In particular, three major indicators such as the side friction coefficient (SFC20°C), mean-profile depth (MPD), and international roughness index (IRI), were measured in a case study and subsequently used in analysis. Regression parameters were estimated by the Maximum Likelihood Method and the t-statistic was considered to show the statistical significance of regression coefficients. The results show that estimation points have the signs expected: the SFC20°C decreases as the number of accumulated trucks (Nt) increases; whereas the MPD and IRI increase as the number of trucks increases. A likelihood ratio test was also carried out to determine whether the system model, which assumes correlation among error terms, was more appropriate than separate models. In this particular case, with three degrees of freedom, was found that the result corresponds to a p-value 0.150 and the null hypothesis cannot be rejected at any significance level less than this value.</p

Gender-related issues in the pharmacology of new anti-obesity drugs

Four new medicines-liraglutide, lorcaserin, bupropion/naltrexone, and phentermine/topiramate-have been recently added to the pharmacological arsenal for obesity treatment and could represent important tools to manage this epidemic disease. To achieve satisfactory anti-obesity goals, the use of these new medicines should be optimized and tailored to specific patient subpopulations also by applying dose adjustments if needed. In the present review, we posit that gender could be among the factors influencing the activity of the new obesity drugs both because of pharmacokinetic and pharmacodynamic factors. Although evidence from premarketing clinical studies suggested that no dose adjustment by gender is necessary for any of these new medicines, these studies were not specifically designed to identify gender-related differences. This observation, together with the strong theoretical background supporting the hypothesis of a gender-dimorphic response, strongly call upon an urgent need of new real-life data on gender-related difference in the pharmacology of these new obesity drugs

Outpatient operative hysteroscopy with bipolar electrode: A prospective multicentre randomized study between local anaesthesia and conscious sedation

BACKGROUND: The study was designed to compare local anaesthesia and conscious sedation for outpatient bipolar operative hysteroscopy in terms of pain control and patients' satisfaction. METHODS: A prospective multicentre randomized study was carried out in university hospitals and in a private endoscopy unit. A total of 166 women with surgically treatable lesions associated with infertility or abnormal uterine bleeding was considered eligible for the study. Patients were randomized, using a computer-generated randomization list, into two groups. Group A (82 patients) underwent operative hysteroscopy with local anaesthesia. Group B (84 patients) received conscious sedation. Operative hysteroscopy was performed with a bipolar electrosurgical device to cut, vaporize and coagulate. Main outcome measures were pain control during the procedure, the post-operative pain score at 15 and 60 min, and at 24 h after the procedure, and patients' satisfaction rate. RESULTS: All procedures were completed within 35 min, the amount of saline used varied from 400-1200 ml. There were no significant differences between local anaesthesia and conscious sedation in terms of pain control during the procedure and in postoperative pain at different intervals. Satisfaction rate was similar in the two groups. CONCLUSIONS: Both local anaesthesia and conscious sedation can be used for operative hysteroscopy using a bipolar electrosurgical system without significant differences in terms of pain control and patients' satisfaction

Assessment of DNA Damage by RAPD in Paracentrotus lividus Embryos Exposed to Amniotic Fluid from Residents Living Close to Waste Landfill Sites

The aim of this study was to assess the genotoxic effects of environmental chemicals on residents living near landfills. The study was based on samples of amniotic fluid from women living in the intensely polluted areas around the Campania region of Italy compared to a nonexposed control group. We evaluated the genetic effects that this amniotic fluids collected in contaminated sites had on Paracentrotus lividus embryos. DNA damage was detected through changes in RAPD (Random Amplified Polymorphism DNA) profiles. The absence of the amplified DNA fragments indicated deletions in Paracentrotus lividus DNA exposed to the contaminated amniotic fluids when compared to equal exposure to uncontaminated fluids. These results show the ability of RAPD-PCR to detect and isolate DNA sequences representing genetic alterations induced in P. lividus embryos. Using this method, we identified two candidate target regions for DNA alterations in the genome of P. lividus. Our research indicates that RAPD-PCR in P. lividus embryo DNA can provide a molecular approach for studying DNA damage from pollutants that can impact human health. To our knowledge, this is the first time that assessment of DNA damage in P. lividus embryos has been tested using the RAPD strategy after exposure to amniotic fluid from residents near waste landfill sites