Recent Developments on Drivable Area Estimation: A Survey and a Functional Analysis

Most advanced autonomous driving systems (ADS) today rely on the prior creation of high-definition maps (HD maps). This process is expensive and needs to be performed frequently to keep up with the changing conditions of the road environment. Creating accurate navigation maps online is an alternative to reduce the cost and broaden the current operational design domains (ODD) of modern ADS. This paper offers a snapshot of the state of the art in drivable area estimation, which is an essential technology to deploy ADS in ODDs where HD maps are limited or unavailable. The proposed review introduces a novel architecture breakdown that fits learning-based and non-learning-based techniques and allows the analysis of a set of impactful and recent drivable area algorithms. In addition to that, complimentary information for practitioners is provided: (i) an assessment of the influence of modern sensing technologies on the task under study and (ii) a selection of relevant datasets for evaluation and benchmarking purposes.

Patterns of milking unit kick-off as a proxy for habituation to milking in primiparous cows

The onset of lactation and the subsequent habituation to the milking routine is a stressful period, particularly for primiparous (PRI) cows. The objective of this study was to describe the dynamics of milking unit kick-off (KO) behavior in PRI cows during the first 3 mo of lactation, considering multiparous (MUL) cows as a reference for comparison. In addition, the potential associations between KO and milk yield and mastitis presentation were investigated. A total of 869 cows (PRI = 199; MUL = 670) on a dairy farm in northern CO were included in the analysis. Cows calving between August and November 2020 were enrolled from 3 DIM until 90 DIM. Participants were milked 3×/day in a 60-unit rotary parlor and data from each milking session were downloaded from parlor management software. Milking unit kick-off was used as a proxy for habituation to the milking procedure. Kick-off events were reported by the milking system and defined as an abrupt interruption in the milk flow during the milking process. Cow KO events were recorded for each milking session. Subsequently, occurrence of KO was analyzed by grouping the 3 consecutive milking sessions in each day and categorized as yes or no, indicating whether or not an individual kicked at least once in a given day. Data were analyzed by repeated measures ANOVA and logistic regression, including parity category, calving season, occurrence of dystocia, and their potential interactions in the models. Least squares means for daily proportions of KO were calculated considering the number of cows with KO events per day in the PRI and MUL categories. Subsequently, odds ratios for the occurrence of KO in PRI versus MUL were calculated at multiple periods of time. When KO was analyzed by DIM, proportions of KO were greater in PRI than in MUL during the whole monitoring period. In PRI, proportions of KO increased from 0.10/d to 0.20/d between 3 DIM and 15 DIM, to start decreasing around 30 DIM and remaining above MUL up to 90 DIM. On the contrary, in MUL cows, proportions of KO remained close to 0.05/d during the 90-d period. Overall, the odds of KO were greater for PRI versus MUL cows (odds ratio [95% confidence interval] = 2.07 [1.58-2.73]). No differences in milk yield were established among KO categories, while the percentage of cows affected with mastitis was greater in cows grouped in the quartile with more frequent KO events. We concluded that the relationship between days in milk and the proportion of PRI cows displaying KO was not linear, but rather KO increased during the first 2 wk postpartum before decreasing after the first month of lactation. First-parity cows had greater levels of KO than MUL cows, which is most likely associated with the process of habituation to milking during their first lactation.

Early Management of Esophageal Leak in Esophageal Atresia: Changing Paradigms

Introduction: A leak at the esophageal anastomosis can occur in 10%-20% of cases of esophageal atresia (EA). Thoracoscopic repair is trans-pleural, with the potential development of an empyema. Standard treatment of an anastomotic leak in a stable patient is often nonoperative, which can lead to prolonged parenteral nutrition and hospitalization. Our objective is to show that early thoracoscopic redo anastomosis management is safe and feasible. Materials and Methods: Retrospective study of a case series of four infants, diagnosed with EA and treated with early thoracoscopic esophageal leak repair between 2013 and 2018. Variables analyzed included age, weight, type of EA, day of leak, surgical approach, time to start feeding, surgical complications, and follow-up. Results: Three patients were type III, and one was type I originally repaired with a thoracoscopic approach. Leaking of the anastomosis was found the second postoperative day in one patient, third day in two patients, and the fifth day in the last one. All were confirmed with an esophagogram. All patients were operated in the first 24 hours after diagnosis by the thoracoscopic approach. The site of leak was found and re-sutured. Patients started feeding between the third and fourth day through a transanastomotic tube, starting oral feeding at the seventh day after an esophagogram did not show a leak. No complications were found. Mean time to complete oral feeding was 10 days. Two patients needed esophageal dilations. Mean time of follow-up has been 33 months. Conclusion: Early thoracoscopic repair of an anastomotic leak can be considered an alternative to the standard nonsurgical management. The early re-suture of the area of leak is a change in paradigm, but it offers the benefits of preservation of the native esophagus, early resumption of enteral feedings, and a shorter length of parental nutrition and hospitalization. Level of Evidence: IV.

Metformin protects from oxaliplatin induced peripheral neuropathy in rats

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After oxaliplatin treatment rats developed mechanical and cold hyperalgesia.

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We observed intraepidermal nerve fiber degeneration, and mild spinal cord gliosis.

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Co treatment with Metformin could prevent all these pathological outcomes.

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This suggests metformin as a candidate drug to prevent oxaliplatin-induced neuropathy.

Oxaliplatin is a commonly used drug to treat cancer, extending the rate of disease-free survival by 20% in colorectal cancer. However, oxaliplatin induces a disabling form of neuropathy resulting in more than 60% of patients having to reduce or discontinue oxaliplatin, negatively impacting their chance of survival. Oxaliplatin-induced neuropathies are accompanied by degeneration of sensory fibers in the epidermis and hyperexcitability of sensory neurons. These morphological and functional changes have been associated with sensory symptoms such as dysesthesia, paresthesia and mechanical and cold allodynia. Various strategies have been proposed to prevent or treat oxaliplatin-induced neuropathies without success. The anti-diabetic drug metformin has been recently shown to exert neuroprotection in other chemotherapy-induced neuropathies, so here we aimed to test if metformin can prevent the development of oxaliplatin-induced neuropathy in a rat model of this condition. Animals treated with oxaliplatin developed significant intraepidermal fiber degeneration, a mild gliosis in the spinal cord, and mechanical and cold hyperalgesia. The concomitant use of metformin prevented degeneration of intraepidermal fibers, gliosis, and the altered sensitivity. Our evidence further supports metformin as a new approach to prevent oxaliplatin-induced neuropathy with a potential important clinical impact.

Smart Sensing of Pavement Temperature Based on Low-Cost Sensors and V2I Communications

Nowadays, the preservation, maintenance, rehabilitation, and improvement of road networks are key issues. Pavement condition is highly affected by environmental factors such as temperature and humidity, hence the importance of building databases enriched with real-time information from monitoring systems that enable the analysis and modeling of the road properties. Information and communication technologies, and specifically wireless sensor networks and computational intelligence methods, are enabling the design of new monitoring systems. The main goal of this work is the design of a pavement monitoring system for measuring temperature at internal layers. The proposed solution is based on low-cost and robust temperature sensors, vehicle-to-infrastructure communications, allowing one to transmit information directly from probes to a moving auscultation vehicle, and a neural network-based model for prediction pavement temperature. User requirements drive probes’ design to a modular device, with easy installation, low cost, and reduced energy consumption. Results of the test and validation experiments show both the benefits and viability of the proposed system, which reflect in an accuracy improvement and reduction in routine test duration. Finally, data collected over a year is applied to assess the performance of BELLS3 models and the suggested neural network for predicting pavement temperature. The dynamic behavior of the predicted temperature and the mean absolute error of the neural network-based model are better than the BELL3 model, demonstrating the suitability of the proposed pavement monitoring system.

[Characteristics and evolution of patients admitted to a public hospital intensive care unit]

BACKGROUND

The epidemiology of critical patients in Chile could differ from that reported in international studies.

AIM

To describe the causes of admission and evolution of patients who were admitted to the ICU (Intensive Care Unit) of a general hospital in Chile in a two-year period (2012-2013).

PATIENTS AND METHODS

A retrospective study was carried out using the ICU database. The following variables were registered: admission diagnosis, APACHE II (Acute Physiology and Chronic Health Evaluation), days of mechanical ventilation (MV), ICU length of stay and ICU and hospital survival.

RESULTS

We analyzed data from 1075 aged 54 ± 18 years (55% males), representing 75% of the admissions during the study period. The median ICU and MV lengths were 5 and 3 days respectively (92% of patients required MV). APACHE II was 20.5 ± 8.2. The ICU and hospital mortality rate were 19.4% and 31%, respectively. Critical neurological diseases were the most common diagnoses requiring ICU, representing 26.8% of the admissions. No differences were found between 2012 and 2013 in age, APACHE II, ICU or hospital survival. A longer post ICU length of stay was found during 2013, both for patients who survived and those who died at the hospital.

CONCLUSIONS

This study highlights the high percentage of patients that required MV and the high percentage critical neurological conditions requiring ICU admission. The characteristics and evolution of patients admitted to the ICU did not differ during 2012 and 2013.

The implementation of an analgesia-based sedation protocol reduced deep sedation and proved to be safe and feasible in patients on mechanical ventilation

INTRODUCTION

Deep sedation in critically ill patients is associated with a longer duration of mechanical ventilation and a prolonged length of stay in the intensive care unit. Several protocols have been used to improve these outcomes. We implement and evaluate an analgesia-based, goal-directed, nurse-driven sedation protocol used to treat critically ill patients who receive mechanical ventilation.

METHODS

We performed a prospective, two-phase (before-after), non-randomized multicenter study that involved 13 intensive care units in Chile. After an observational phase (observational group, n=155), we designed, implemented and evaluated an analgesia-based, goal-directed, nurse-driven sedation protocol (intervention group, n=132) to treat patients who required mechanical ventilation for more than 48 hours. The primary outcome was to achieve ventilator-free days by day 28.

RESULTS

The proportion of patients in deep sedation or in a coma decreased from 55.2% to 44.0% in the interventional group. Agitation did not change between the periods and remained approximately 7%. Ventilator-free days to day 28, length of stay in the intensive care unit and mortality were similar in both groups. At one year, post-traumatic stress disorder symptoms in survivors were similar in both groups.

CONCLUSIONS

We designed and implemented an analgesia-based, goal-directed, nurse-driven sedation protocol in Chile. Although there was no improvement in major outcomes, we observed that the present protocol was safe and feasible and that it resulted in decreased periods of deep sedation without increasing agitation.

[Characteristics of trauma patients admitted to the intensive care unit of a general hospital in Chile]

BACKGROUND

Trauma is an important cause of death among young adults.

AIM

To determine the characteristics, treatments and evolution of trauma patients admitted to an intensive care unit (ICU) of a public hospital in Santiago, Chile.

MATERIAL AND METHODS

All polytrauma (PT) and severely traumatized (ST) patients admitted to ICU were included. We recorded the type of trauma along with demographic and hemodynamic variables, treatments and complications. The evolution and treatments received by PT and ST patients were compared.

RESULTS

We recorded data from 72 patients aged 43 ± 21 years (93% males). Sixty two percent were PT and 24% had penetrating injuries. TBI (Trauma Brain Injury) was the most common trauma. On admission, acute Physiology and Chronic Health Evaluation II (APACHE II) score was 18.7 + 7.3, and Injury Severity Score (ISS) was 32.8 + 20.1. ICU stay was 7.8 + 6 days. Sixty seven per cent of patients required surgery and 58% received blood transfusions. No differences were found between PT and ST. ICU and hospital mortality rates were 15 and 25% respectively.

CONCLUSIONS

The characteristics and evolution of PT and ST of this series of patients are similar to those described abroad. Mortality was in agreement with ISS and APACHE II scores.

Liver transplantation in children weighing less than 10 kg: Chilean experience

BACKGROUND

Orthotopic liver transplantation is the treatment of choice for most terminal liver diseases in children. In small children (≤ 10 kg), this procedure is challenging and has special considerations. The aim of this study is to describe the experience of a Chilean liver transplantation program in this subgroup of patients.

METHODS

The liver transplant database of Hospital Luis Calvo Mackenna and Clinica Las Condes was reviewed. All children less than 10 kg undergoing liver transplantation between January 1994 and July 2011 were included. Patient and graft outcomes and main complications were analyzed.

RESULTS

We have performed 230 pediatric liver transplantations, 49 of them in 41 patients weighing less than 10 kg. The first indication for transplantation was biliary atresia in 25 patients (61%). A living related donor was used in 23 cases (51%). Actuarial survival was 75.7% at 1 year and 67.1% at 5 years. The main cause of death was infection, and the leading cause of graft loss was vascular complication.

DISCUSSION

Our transplant program includes 2 centers that perform more than 90% of pediatric liver transplantations in Chile, including public health pediatric patients from all around the country. Patients weighing less than 10 kg represent the most challenging group in pediatric liver transplantation due to higher rates of vascular and biliary complications and postoperative infections.

Primera caracterización morfoestructural y faneróptica del Perro Ovejero Magallánico, Chile

El presente estudio se realizó con el objetivo de proporcionar una primera aproximación etnológica del perro Ovejero Magallánico. Esta población canina se ubica en la región de Magallanes (48°37" a los 56°30" latitud sur), Chile, en donde cumple un rol fundamental como animal de trabajo en la ganadería ovina de la zona. Esta población canina es el producto de la cruza de perros ovejeros británicos llegados a la zona a fines del siglo XIX y comienzos del XX, que se han adaptado por más de un siglo a las duras condiciones climáticas de la Patagonia Chilena. Se realizó un muestreo dirigido a perros que cumplieran con las características morfológicas que los ganaderos de Magallanes asocian a esta población canina. Se analizaron variables zoométricas en 75 perros (43 machos y 32 hembras) adultos. Para las variables fanerópticas se utilizaron los 75 perros, mientras que para la variable morfoestructural solo fueron considerados 62 perros, ya que 13 individuos entre 1 y 2 años presentaron excesiva variabilidad. Los resultados obtenidos permiten establecer que el Ovejero Magallánico presenta una marcada uniformidad morfoestructural, definido dimorfismo sexual y un conjunto de caracteres fanerópticos distintivos, aspectos que son importantes en la definición racial de una población canina. Este estudio constituye la primera caracterización zoométrica del perro Ovejero Magallánico y contribuye a establecer las bases para estudios posteriores necesarios para implementar el estándar oficial de la raza.

Ultrasonic sensors in urban traffic driving-aid systems

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultrasonic sensors in active safety systems for urban traffic is proposed, and the advantages and disadvantages when compared to other sensors are discussed. Adaptive Cruise Control (ACC) for urban traffic based on ultrasounds is presented as an application example. The proposed system has been implemented in a fully-automated prototype vehicle and has been tested under real traffic conditions. The results confirm the good performance of ultrasonic sensors in these systems.

Chilean experience in liver transplantation for acute liver failure in children

BACKGROUND

Acute liver failure (ALF) in children is a life-threatening condition, associated with high mortality, and in almost one third of the cases, with no other therapeutic option than orthotopic liver transplant (OLT). The aim of this study was to present our experience with OLT for ALF in pediatric patients in Chile. Patients fulfilling the criteria for ALF who were transplanted in our centers were prospectively included in an excel Microsoft database. We analyzed demographics, etiology, surgical techniques, complications, and long-term results.

PATIENTS AND METHODS

Between 1994 and 2009, we transplanted 52 pediatric patients with ALF. The most frequent known etiology was acute hepatitis A in 9 cases (18%), but in 26 cases (50%) it was impossible to determine the etiology. Thirty- one patients were males (63%). The overall mean age was 7.5 years and the mean weight, 28.1 kg. Thirty-five (67%) received a cadaveric graft. Among them in 18 cases (34%) the liver had to be reduced but 17 (33%) received whole livers. There were 17 (33%) recipients of living-related livers. Twenty-two patients needed reoperation, including 13 due to surgical complications (59%) and 9 (41%) as planned interventions. Ten patients were retransplanted.

RESULTS

Actuarial survival of patients at 1 year was 80% and at 5 and 10 years, 72%. Graft survival at 1 year was 79%, at 5 years 69%, and at 10 years 50%.

CONCLUSION

We have reported a series of pediatric liver transplant patients due to ALF whose results were comparable to other reported series. Living donor transplantation for ALF should be considered and offers a low morbidity rate without mortality.

Coping self-efficacy in a community-based sample of women and men from the United Kingdom: the impact of sex and health status

This study presents pioneer findings regarding coping self-efficacy obtained with the Coping Self-Efficacy Scale (CSES) in a community-based sample composed of both women and men (to date, only data obtained in the 1980s from men with HIV and depression exist). The aims of this study were to investigate the psychometric properties of the CSES and obtain descriptive results in a British community-based sample composed of both women and men. Participants responded to both the CSES and another scale measuring coping with stress self-efficacy. Based on our findings, the CSES showed appropriate reliability and construct validity, although some items require revision. We found that sex and, particularly, health status play an important role in individual differences in coping self-efficacy. Women showed significantly stronger self-efficacy beliefs for social support than men, while for the remaining scores, men scored higher than women. Healthy participants showed significantly stronger self-efficacy beliefs (for social support, NS) than unhealthy participants. The results confirmed both the suitability of the CSES as a measure of a person's confidence in his or her perceived ability to perform certain actions aimed at coping effectively with stress in a nonbiased sample and its soundness in research and clinical contexts.

ICRP Publication 114. Environmental protection: transfer parameters for reference animals and plants

In Publication 103 (ICRP, 2007), the Commission included a section on the protection of the environment, and indicated that it would be further developing its approach to this difficult subject by way of a set of Reference Animals and Plants (RAPs) as the basis for relating exposure to dose, and dose to radiation effects, for different types of animals and plants. Subsequently, a set of 12 RAPs has been described in some detail (ICRP, 2008), particularly with regard to estimation of the doses received by them, at a whole-body level, in relation to internal and external radionuclide concentrations; and what is known about the effects of radiation on such types of animals and plants. A set of dose conversion factors for all of the RAPs has been derived, and the resultant dose rates can be compared with evaluations of the effects of dose rates using derived consideration reference levels (DCRLs). Each DCRL constitutes a band of dose rates for each RAP within which there is likely to be some chance of the occurrence of deleterious effects. Site-specific data on Representative Organisms (i.e. organisms of specific interest for an assessment) can then be compared with such values and used as a basis for decision making. It is intended that the Commission's approach to protection of the environment be applied to all exposure situations. In some situations, the relevant radionuclide concentrations can be measured directly, but this is not always possible or feasible. In such cases, modelling techniques are used to estimate the radionuclide concentrations. This report is an initial step in addressing the needs of such modelling techniques. After briefly reviewing the basic factors relating to the accumulation of radionuclides by different types of biota, in different habitats, and at different stages in the life cycle, this report focuses on the approaches used to model the transfer of radionuclides through the environment. It concludes that equilibrium concentration ratios (CRs) are most commonly used to model such transfers, and that they currently offer the most comprehensive data coverage. The report also reviews the methods used to derive CRs, and describes a means of summarising statistical information from empirical data sets. Emphasis has been placed on using data from field studies, although some data from laboratory experiments have been included for some RAPs. There are, inevitably, many data gaps for each RAP, and other data have been used to help fill these gaps. CRs specific to each RAP were extracted from a larger database, structured in terms of generic wildlife groups. In cases where data were lacking, values from taxonomically-related organisms were used to derive suitable surrogate values. The full set of rules which have been applied for filling gaps in RAP-specific CRs is described. Statistical summaries of the data sets are provided, and CR values for 39 elements and 12 RAP combinations are given. The data coverage, reliance on derived values, and applicability of the CR approach for each of the RAPs is discussed. Finally, some consideration is given to approaches where RAPs and their life stages could be measured for the elements of interest under more rigorously controlled conditions to help fill the current data gaps.

[Characteristics and impact of sedation, analgesia, and neuromuscular blockage in critical patients undergoing prolonged mechanical ventilation]

AIM

To describe use of sedatives, analgesics, and neuromuscular blockers (NMB) in patients undergoing long-term mechanical ventilation and to assess factors associated with their use and their association with mortality at 28 days.

DESIGN

Prospective observational multicenter cohort study.

SETTING

Thirteen intensive care units (ICU) in Chile.

PATIENTS

Patients undergoing mechanical ventilation for more than 48h. We excluded patients with neurological disorders, cirrhosis of the liver, chronic renal failure, suspected drug addiction, and early no resuscitation orders.

INTERVENTION

None.

MAIN MEASUREMENTS

Proportion of use and dosage of sedatives, analgesics, and NMB. Level of sedation observed (SAS). Variables associated with the Sedation Agitation Scale (SAS), use of sedatives, analgesics, and NMB. Multivariate logistic regression of variables associated to mortality at 28 days.

RESULTS

A total of 155 patients participated (60+/-18 years, 57% male, SOFA 7 [6-10], APACHE II 18 [15-22], 63% with sepsis, and 47% with acute lung injury/adult respiratory distress syndrome. The drugs most frequently used were midazolam (85%, 4 [1.9-6.8]mg/hr) and fentanyl (81%, 76 [39-140]microg/hr). NMB were administered at least 1 day in 30% of patients. SAS score was 1 or 2 in 55% of patients. There was an association between NMB use and mortality at 28 days, but it was not consistent in all the models of NMB evaluated.

CONCLUSIONS

Sedatives were frequently employed and deep sedation was common. Midazolam and fentanyl were the most frequently administered drugs. The use of NMB might be independently associated to greater mortality.

Cost-effectiveness analysis of first-line treatment for metastatic renal cell carcinoma (mRCC) in Colombia (ONCOLGroup study)

e16150

Background: Renal cell carcinoma has increased its incidence by 126% since 1950. A local study developed a complete economic evaluation of sunitinib versus IFN in first-line treatment of mRCC in Colombia, finding that sunitinib was more cost-useful and cost-effective. Methods: A Markov model was developed using 6-week cycles for evaluating the cost-effectiveness of four interventions (IFN, sunitinib, bevacizumab+IFN, sorafenib) approved as first-line treatment for mRCC in Colombia. The model used the third-party payer perspective and a 5-year time-line; it also presumed that all the patients (pts) continued with active treatment until progression when it became acceptable to continue with a second-line treatment or BSC. Overall survival (OS) and progression-free survival (PFS) curves of IFN were used as reference framework; they were obtained form a published clinical trial. The hazard ratios (HR) for PFS and OS were estimated for comparing new generation medicaments with IFN. The information about frequency of use and health service cost units consumed in Colombia was taken from a series of 24 pts treated in Manizales, Pereira, Medellín and Bogotá. Service costs were requested from an external consultant and corresponded to the average value billed by the EPSs, calculated from 33 sources of information which were representative of the country's market. The cost of the medicaments was obtained from LCLC. The costs and benefits were discounted annually at 3%. (all cost are presented in Colombian pesos Col$ 2008 with an exchange rate 1 USD = 1836.20 Col$). Results: Incremental analysis indicated a difference of 41.1 million Col$ in the average total cost of treatment when Sunitinib was compared to IFN; in contrast, comparing sorafenib and Bevacizumab+INF to sunitinib demonstrated that the average total cost was less for the sunitinib by 8.3 and 104.2 million Col$, respectively. Additionally, the ratios of incremental cost-effectiveness by life years (LY) gained demonstrated sunitinib's simple dominance over sorafenib and the combination of bevacizumab+IFN, and an average by LY gained of 100.5 million Col$ compared to IFN. Conclusions: Sunitinib is the most cost-effective option as first-line treatment for mRCC pts in Colombia.

[Table: see text]

Expression and activity of 11beta-hydroxysteroid dehydrogenase type 1 enzyme in subcutaneous and visceral adipose tissue of prepubertal children

BACKGROUND

Glucocorticoid excess promotes visceral obesity and cardiovascular disease. Ligand availability to the glucocorticoid receptor is controlled by isoforms of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) which converts endogenous cortisone to active cortisol.

AIM

To evaluate the expression and activity of 11beta-HSD1 in subcutaneous adipose tissue (SC) and visceral adipose tissue (VAT) in prepubertal children with normal weight.

METHODS

Fourteen patients (11 female/3 male) with a mean age of 6.9+/-0.9 years and a body mass index (BMI) of 17.4+/-0.61 underwent elective open abdominal surgery.

RESULTS

Expression of 11beta-HSD1 mRNA in SC and VAT was similar (0.8+/-0.15 vs. 0.61+/-0.12 AU). The activity of this enzyme in SC was significantly lower compared to VAT (1.42+/-0.39 vs. 2.79+/-0.61 ng cortisol/g tissue/24 h, p<0.05). In addition, we observed a significant direct correlation with the expression of 11beta-HSD1 in VAT adipose tissue with the patient's BMI (r=0.825, p=0.002).

CONCLUSIONS

This correlation together with the increased activity of this enzyme in visceral adipose tissue might contribute to decreased hepatic insulin sensitivity due to increased portal cortisol when BMI increases. These observations appear to be particularly important in children born with low birth weight who develop rapid early weight gain.

[Characteristics and factors associated with mortality in patients receiving mechanical ventilation: first Chilean multicenter study]

BACKGROUND

The outcome of mechanically ventilated patients can be influenced by factors such as the indication of mechanical ventilation (MV) and ventilator parameters.

AIM

To describe the characteristics of patients receiving MV in Chilean critical care units.

MATERIAL AND METHODS

Prospective cohort of consecutive adult patients admitted to 19 intensive care units (ICU) from 9 Chilean cities who received MV for more than 12 hours between September lst, 2003, and September 28th, 2003. Demographic data, severity of illness, reason for the initiation of MV, ventilation modes and settings as well as weaning strategies were registered at the initiation and then, daily throughout the course of MV for up to 28 days. ICU and hospital mortality were recorded.

RESULTS

Of 588 patients admitted, 156 (26.5%) received MV (57% males). Mean age and Simplified Acute Physiology Score-II (SAPS II) were 54.6+/-18 years and 40.6+/-16.4 points respectively The most common indications for MV were acute respiratory failure (71.1%) and coma (22.4%). Assist-control mode (71.6%) and synchronized intermittent mandatory ventilation (SIMV) (14,2%) were the most frequently used. T-tube was the main weaning strategy. Mean duration of MV and length of stay in ICU were 7.8+/-8.7 and 11.1+/- 14 days respectively. Overall ICU mortality was 33.9% (53 patients). The main factors independently associated with increased mortality were (1) SAPS II > or =60 points (Odds Ratio (OR), 10.5; 95% CI, 1.04-106.85) and (2) plateau pressure > or =30 cm H2O at second day (OR, 3.9; 95% CI, 1.17-12.97).

CONCLUSIONS

Conditions present at the onset of MV and ventilator management were similar to those reported in the literature. Magnitude of multiorgan dysfunction and high plateau pressures are the most important factors associated with mortality.

Early steroid withdrawal in pediatric renal transplant on newer immunosuppressive drugs

Steroids have been a cornerstone in renal transplant immunosuppression. New immunosuppressive drugs have led to protocols using early steroid withdrawal or complete avoidance. A prospective protocol in 23 pediatric renal transplant (ages 2-14 yr) who received decreasing steroid doses stopping at day 7 post-Tx, FK, and MMF were compared with a CsA, AZT, historically matched steroid-based control group. Basiliximab was used in two doses. Anthropometric, biochemical variables, AR rates, and CMV infection were evaluated and compared using Student's t-test and regression analysis. A better growth pattern was seen in steroid withdrawal group. GFR rate and serum glucose were similar in both groups. Total serum cholesterol levels were significantly lower in steroid withdrawal group. The incidence of AR at 12 months was 4.3% in steroid withdrawal group vs. 8.6% in steroid-based group (p = ns). No difference in CMV infection was observed. Hemoglobin levels were low during the first months in both groups; reached normal values after six months. SBP became higher at 12 months in steroid-based group. Patient and graft survival was 98% in both groups at one-yr post-transplant. Early steroid withdrawal was efficacious, safe, and did not increase risk of rejection, preserving optimal growth, renal function, and reducing cardiovascular risk factors.

[Cyclosporine-induced gingival hyperplasia: report of one case]

Gingival enlargement can be an adverse effect of cyclosporine A and nifedipine use. It has a high relapse rate if the drugs are not discontinued. There is a genetic predisposition to the development of this condition and dental biofilm can also play a role. We report a 64 years old male who received a renal allograft and was treated with cyclosporine and nifedipine. He required six surgical interventions for generalized gingival enlargement. After the sixth relapse, the patient was subjected to a periodontal treatment to eliminate the dental biofilm, which decreased the rate of recurrence of gingival enlargement.

Pediatric Liver Retransplantation: Indications and Outcome

INTRODUCTION

Liver transplantation is the only treatment for end-stage liver disease. Not all patients have a favorable outcome. Graft failure secondary to primary nonfunction, vascular complications, or chronic rejection among other problems may lead to retransplantation. Retransplantation represents 8% to 29% of liver transplantations in the pediatric population. The aim of this study was to present our experience with retransplanted children by analyzing the indications and the results.

METHODS

All patients were prospectively included in our database, including 125 children. We included the indications for retransplantation, complications, and mortality. Kaplan-Meier curves were used for survival analysis.

RESULTS

Since 1994, 125 patients were transplanted and 25 were retransplanted (20%), including 5 who received a third graft. Primary nonfunction represented 30% of the indications for retransplantation and hepatic artery thrombosis, 20%. Six of 25 patients who received a first retransplantation and 2 of 5 who received a second retransplantation died. The most frequent cause of death was multiorgans failure. The survivals at 1 and 5 years were 82% and 76% for children receiving a first retransplantation, and 60% at 1 and 5 years for those who received a second retransplantation.

CONCLUSIONS

Organ failure after liver transplantation was a common event in pediatric transplantation. Survival was similar between patients transplanted once and those who received one retransplantation. Survival decreased among patients who received a third graft but was maintained at 60%, which is better than most published results for first retransplanted patients. Retransplantation is a valid option with good results for selected pediatric cases.

Oral Ulcers Produced by Mycophenolate Mofetil in Two Liver Transplant Patients

Oral ulcers are a frequent problem in transplant medicine. It is important to consider infectious etiologies, exacerbated by the immunosuppressive treatment, but other etiologies are also possible, like adverse drug reactions. Mycophenolate mofetil (MMF) is an immunosuppressive medication that has been used in combination with calcineurin inhibitors and steroids. Reports of renal transplant patients with oral ulcers related to MMF have appeared lately and herein we have described 2 cases in liver transplant patients. Their oral ulcers resolved quickly after suspension of the medication. Our 2 cases in liver transplant patients represented a unique setting for this type of complication.

Pediatric renal transplantation: a single center experience over 14 years

Between 1989 and 2003, 100 transplants were performed in 96 patients at the pediatric nephrology unit of the Calvo Mackenna Children's Hospital. Mean age 10.9 +/- 3.9 yr (1-17.6), 30% from LD. Donors were younger than 5 yr in five patients and all recipients received an 'en bloc' graft. Original disease was hypo/dysplasia 27%, reflux nephropathy 22 and 17% chronic glomerulonephritis. The immunosuppressive protocol during the first period (n = 56, 1989-2000): Cyclosporine, steroids and azathioprine, and during the second period (n = 44, 2001-2003): FK, steroids, MMF and anti-CD25 antibody (mAbs). AR was reported in 22 patients, 11% in LD, 31% in DD (p < 0.01). The AR rate decreased from 40 to 8% after anti-CD25 monoclonal induction. Patient actuarial survival rate at 1, 3 and 5 yr was 100% for LD and 96% for DD. The overall actuarial graft survival at 1,3, and 5 yr was 96.7, 96.7 and 71% for LD and 89, 76 and 73% for DD donors. Graft survival rate improved from the first period (1989-2000) to the second period (2001-2003; p = 0.05). No difference in graft survival rate with HLA-A,B,DR matching was found. Graft survival rate was better when cold ischemia time was <24 h (p < 0.01). CMV infections increased from 19 to 40% when MMF and anti-CD25 Ab were introduced (p < 0.01). The height/age Z score at 1, 3 and 5 yr post-transplant was -2.2, -2.1, -2.2, respectively, for children older than 7 yr and -1.8, -1.9, -2.1 for those transplanted younger than 7 yr of age who were switched to alternate day steroids (p < 0.01). The cause of graft lost was: chronic rejection eight, non-adherence four, AR four and vascular thrombosis two. The cause of death in two patients was fungus septicemia and accelerated rejection. Pediatric renal transplantation can be performed in our group with acceptable morbidity, low mortality and graft survival rates similar to other reports in North America and Western Europe. Graft survival rate improved with newer immunosuppression and greater experience at the center. Management of non-adherence and chronic rejection remain the major challenges.

Combined Liver and Kidney Transplantation in a Multicenter Transplantation Program in Chile

INTRODUCTION

Combined liver and kidney transplantation (CLKT) is an exceptional therapeutic procedure limited to a few diseases with advanced compromise of these organs. Hyperoxaluria type I and polycystic disease are the most frequent indications. The aim of this article was to report our indications and results of CLKT in a multicenter transplantation program in Chile.

MATERIAL AND METHODS

Our Excel database was reviewed to select patients who were treated with CLKT between 1993 and July 2004.

RESULTS

Among 242 liver transplantations (LT) and 48 kidney transplantations (KT), 7 were CLKT, representing 2.8% of LT and 14.5% of KT. Four patients were women and 3 were male of average age 46.8 years. One patient was a child. Most frequent indications were chronic renal failure associated with terminal liver disease and polycystic disease. One patient needed liver retransplantation due to hepatic vein thrombosis. One patient had a biliary fistula and another had a urinary fistula, treated conservatively. Acute liver rejection took place in 3 cases, 1 of which required antibodies. Two patients died, 1 due to aspergillosis and the other due to vascular complications in the transplanted liver. Actuarial survival rates were 71.4% at 1 and 5 years. Chronic renal failure is not a contraindication to LT.

CONCLUSION

CLKT is an acceptable option for these patients.

Living Related Liver Transplantation. Why This Option Has Been Discarded in a Pediatric Liver Transplant Program in Chile

Living related living transplantation (LRLT) has opened new possibilities for planning transplantation in better conditions for children with emergency situations and chronic liver diseases. Since we began the LRLT program in 1999, we have performed 57 pediatric liver transplants, 17 (29.8%) using living related donors (LRD). The aim of this study was to analyze the reasons why LRD were discarded as a therapeutic option. All pediatric patients were prospectively included in our Microsoft Excel database that was reviewed for obtaining information about causes why the LRLT could not be done. LRLT was proposed in 28 cases and performed in 17 (60.7%). The reasons for LRD rejection were: parent's fear of surgical complications in four cases; drug abuse in two; a mother without family support; medical reasons in two; and only one, due to anatomical reasons and in one case, cadaveric graft transplantation was performed while completing the father's evaluation. From these eleven cases, the indications for liver transplant were acute liver failure (ALF) in seven, biliary atresia in three, and Alagille syndrome in one. Nine were transplanted with cadaveric organs, but two patients with ALF died awaiting a liver. Efforts should be made to clarify the advantages and the disadvantages of LRD in each case, allowing parents to make a free, well-informed decision.

Pediatric Liver Transplantation: Ten Years of Experience in a Multicentric Program in Chile

Liver transplantation is the only treatment for patients with terminal acute and chronic diseases. Liver transplantation was started in Chile in 1985; our pediatric program began in 1993. The aim of this paper work was to present our experience from 1993 through 2004. One hundred and thirty two orthotopic liver transplants (OLT) were performed in children of mean age 5 years and median age 4 years (8 months to 15 years). The most frequent indications were biliary atresia, (43.1%) and acute liver failure (ALF; 20.4%), whose frequent cause was unknown but viral hepatitis A was the second one. A complete liver was transplanted in 59 patients, reduced in 39, split in one, and as an auxiliary liver in another one. Living related liver transplantation was performed in 32 cases (24.2%), of which thirty included segments II and III, and two, a right liver. A terminal arterial anastomosis was performed in 102 (77.2%) recipients and a graft interposition in 32 patients (24.2%). In 16 cases, biliary reconstruction was performed through an enterobiliary anastomosis. Immunosuppression included cyclosporine (Neoral), steroids, and azathioprine with conversion to tacrolimus (Prograf) as indicated. Rejection episodes, which were always biopsy-proven, were treated either with methylprednisolone or with antibodies. Biliary complications were the most frequent (21.4%) and the second cause was vascular complications (13%). Sixty-six patients suffered an acute rejection episode. Actuarial graft survival was 81.3% at 1 year and 72% at 5 years, while actuarial graft survival for ALF was 75.9% at 1 year and 67.8% at 5 years. Our results are comparable to those reported by most international groups.

ABO-incompatible liver transplantation: a new therapeutic option for patients with acute liver failure in Chile

Different ways have been suggested to expand donor numbers for liver transplantation. Transplantation using ABO-incompatible hepatic grafts has recently been a controversial issue due to the high risk of hyperacute rejection mediated by preformed anti-ABO antibodies. We report three patients with acute liver failure who were transplanted with ABO-incompatible livers: A to O in two patients and A to B in one case. We used pre- and posttransplant total plasma exchange, splenectomy, and triple immunosuppression. All three patients are alive; one graft was lost, probably secondary to thrombotic microangiopathy with low isohemagglutinin titers of 1:8. One patient developed acute cellular rejection that was reversed with a bolus of methylprednisolone. No antibody-mediated rejection occurred. Financial and infectious considerations have to be considered. In our series, the final liver transplantation cost was higher than average for acute liver failure. Plasmapheresis has the highest cost of all the additional procedures. ABO-incompatible liver transplantation, because of the splenectomy it requires, has been associated with more infections due to encapsulated organisms. However, with splenectomy in our three patients, none had infections due to these bacteria. In our country, we do not consider ABO-incompatible liver transplantation as a first-line option, except for highly selected patients.

Pediatric Renal Transplantation: 13 Years of Experience—Report From The Chilean Cooperative Multicenter Group

Between 1989 and 2002, 178 renal transplants were performed in 168 pediatric patients in Chile. The mean age was 10.9 +/- 3.7 years (range 1 to 17.9). End-state renal disease etiologies were: congenital renal hypoplasia/dysplasia, chronic glomerulonephritis, and reflux nephropathy. Seventy received a graft from a living donor (LD), and 108 from a cadaveric donor (CD). Only 9% received antibody induction. Acute rejection episodes were reported in 76 patients: 38% in LD recipients and 48% in CD recipients (P = NS). One-, 3-, and 5-year graft survivals were 88%, 84%, and 76%, respectively, for LD and 86%, 79%, and 68% for CD recipients. Actuarial graft survival was significantly better among those patients with serum creatinine < 1 mg/dL at 1 year posttransplant compared with those with creatinine > 1 mg/dL (P < .05). The graft survival rate has improved from the first period (1989 to 1996) to the second period (1997 to 2002); (P = .05). Patient survival rates at 1, 3, and 5 years were 98%, 98%, and 98%, respectively, for LD, and 95%, 94%, and 94% for CD. Global height/age Z-score decreased from -0.7 at birth to -1.5 when dialysis started, and to -2.4 at the time of transplantation. The Z-score height/age at 1, 3, and 5 years posttransplantation was -2.25, -2.24, and -2.5. No significant differences were observed in transplant outcomes comparing patients younger than 7 years with those older ones. In conclusion, pediatric renal transplant has been performed in Chile with acceptable morbidity. The patient and graft survivals are similar to the reported international experience. In the last period there was a significant improvement in graft survival.

Epidemiology and results of liver transplantation for acute liver failure in Chile

Acute liver failure (ALF) is a severe, life-threatening condition associated with a high mortality rate. The objective of this study is to present the experience of a Chilean liver transplant program with orthotopic liver transplantation (OLT) for ALF. All patients with the diagnosis of ALF evaluated in our program between January 1995 and May 2003 were included in the analyses of etiology and outcomes. Candidates for OLT activated on a national waiting list were transplanted with cadaveric or living-related donor (LRD) organs. Twenty-seven patients age 1 to 19 years (median, 7.4 years) were transplanted at a median weight of 30.7 kg including 17 cadaveric and 10 with LRD livers. Most frequent etiologies were hepatitis A in 10 cases (37%) and unknown in 12 (48.1%). One donor experienced superficial phlebitis. Four patients were retransplanted (14.8%). Twenty patients are alive with 1- and 5-year survival rates of 74.1% At a median follow up of 34 months (range = 2 to 120). Seven patients died due to sepsis, multiorganic failure, graft primary nonfunction, intracranial hemorrhage, and intraoperative cardiac arrest. This experience revealed results comparable to international reports, allowing survival of patients destined to die.

Outcomes of orthotopic liver transplantation in Chile

Our liver transplant program was started in 1993 in a private clinic and a public hospital. Thereafter, a rapid increase in adults and pediatric candidates for this therapeutic option lead to this analysis of results in 165 orthotopic liver transplants (OLT) in 143 patients between November 1993 and December 2002. Seventy-four OLT were performed in 66 adult patients and 91 in the pediatric group. Liver grafts came from cadaveric donors in 145 cases (74 adults and 71 children). The technique of living-related donor was utilized in 20 pediatric cases. Main indications for OLT in the adult group were HCV cirrhosis, primary biliary cirrhosis; biliary atresia and acute liver failure were the indications in pediatric patients. Retransplantation was needed for 23 patients, including 9 adults and 14 children. The most frequent causes of death were sepsis, graft primary nonfunction, and vascular complications. Actuarial survivals at 1 and 5 years were 80.7% and 72.6% for the adult group and 82% and 74.8% for the pediatric group, respectively. Our results are comparable to those published by large, experienced, international centers, with much better financial support.

CYP1A1, CYP2E1 and GSTM1 genetic polymorphisms. The effect of single and combined genotypes on lung cancer susceptibility in Chilean people

CYP1A1, CYP2E1 and GSTM1 polymorphisms were evaluated in Chilean healthy controls and lung cancer patients. In the Chilean healthy group, frequencies of CYP1A1 variant alleles for MspI (m2 or CYP1A1*2A) and ile/val (val or CYP1A1*2B) polymorphisms were 0.25 and 0.33, respectively. Frequencies of variant alleles C (CYP2E1*6) and c2 (CYP2E1*5B) for CYP2E1 were 0.21 and 0.16, respectively and frequency for GSTM1(-) was 0.24. The presence of variant alleles for GSTM1, MspI and Ile/val polymorphisms was more frequent in cases than in controls. However, frequencies for the c2 and C alleles were not significantly different in controls and in cases. The estimated relative risk for lung cancer associated to a single mutated allele in CYP1A1, CYP2E1 or GSTM1 was 2.41 for m2, 1.69 for val, 1.16 for C, 0.71 for c2 and 2.46 for GSTM1(-). The estimated relative risk was higher for individuals carrying combined CYP1A1 and GSTM1 mutated alleles (m2/val, OR=6.28; m2/GSTM1(-), OR=3.56) and lower in individuals carrying CYP1A1 and CYP2E1 mutated alleles (m2/C, OR=1.39; m2/c2, OR=2.00; val/C, OR=1.45; val/c2, OR=0.48; not significant). The OR values considering smoking were 4.37 for m2, 4.05 for val, 3.47 for GSTM1(-), 7.38 for m2/val and 3.68 for m2/GSTM1(-), higher values than those observed without any stratification by smoking. Taken together, these findings suggest that Chilean people carrying single or combined GSTM1 and CYP1A1 polymorphisms could be more susceptible to lung cancer induced by environmental pollutants such as polycyclic aromatic hydrocarbons.

Esophageal motor dysfunction persists in children after surgical cure of reflux: an ambulatory manometric study

BACKGROUND/PURPOSE

Esophageal dysmotility shown by perfusion manometry in children with gastroesophageal reflux can be primary or acquired. This study examines by combined ambulatory pH-metry and manometry the nature of motor dysfunction and whether it improves after surgical cure of reflux.

METHODS

Sixteen refluxing children aged 131 +/- 54 months were studied by combined ambulatory pH-metry and manometry before and more than 6 months after successful fundoplication. pH-metric and manometric variables were compared at both time end-points by paired statistical tests accepting a significance level of P less than.05.

RESULTS

Operation cured all patients clinically and pH-metrically, but, in spite of this, only the frequency of motor sequences decreased significantly after the operation from 1 (0.45) to 0.8 (0.6) waves per minute (median [interquartile range]). Wave amplitude and duration were similar in both conditions; the proportion of peristaltic waves was normal and did not change before and after the operation (79.5% [17.25] v 81.4% [21.5]; not significant), whereas the proportions of complete (63.2% [17.5] v 67.8% [19.3]; not significant) and effective (32.4% [31.95] v 27.25% [22.5]; not significant) waves were definitely low and remained so after treatment.

CONCLUSIONS

The esophagus of children with GER has mild disturbances of peristaltic activity with waves often incomplete, weak, and scarcely effective. Dismotility does not improve after successful fundoplication suggesting that it could be a primary phenomenon.

Acetylcholinesterase-amyloid-beta-peptide interaction and Wnt signaling involvement in Abeta neurotoxicity

Previous studies have indicated that acetylcholinesterase (AChE) promotes amyloid-beta-peptide (Abeta) fibril formation and AChE-Abeta complexes increase Abeta-dependent neurotoxicity. Here we present evidence for the: i) identification of the AChE motif that promotes amyloid formation, ii) in vivo effect of AChE on brain plaque formation, and iii) connection between AChE-Abeta neurotoxicity and the Wnt signal transduction pathway. Computer modeling, stereotaxic infusions and cell biological techniques were used to study the above problems. Results indicated that a 3.4 kDa AChE peptide promotes Abeta fibril formation. AChE infusion into rat hippocampus determines the appearance of anti-Abeta and thioflavine-S positive plaques, and AChE-Abeta toxicity on hippocampal cultures was blocked by lithium, an activator of the Wnt cascade. We suggest that AChE-Abeta/Abeta dependent neurotoxicity may result in loss of function of Wnt signaling components, and open the possibility that lithium may be considered as a candidate for therapeutic intervention in Alzheimer's disease pathology.