Controlling antimicrobial activity and drug loading capacity of chitosan-based layer-by-layer films.

We report on layer-by-layer (LbL) films of chitosans (CHI) and hyaluronic acid (HA) whose properties could be controlled by employing chitosans with different degrees of deacetylation (DD¯ ≈ 85%; 65%; 40%) and high average molecular weight (ca. 106 g/mol). In spite of their high molecular weight, these chitosans are soluble within a wide pH range, including physiological pH. HA/CHI LbL films produced from polymer solutions at pH 4.5 were thinner, smoother, more hydrophilic than those prepared at pH 7.2. This is attributed to the more extended conformation adopted by chitosan due to its very high charge density at low pH, favoring a compact chain packing during the film formation and resulting in lower film thickness and roughness. The smoother HA/CHI LbL films obtained at pH 4.5 were effective against Escherichia coli, while the thicker, rougher LbL films fabricated at pH 7.2 could be used in the controlled released of Rose Bengal dye. In summary, the tuning of only two parameters, i.e. solution pH and DD¯ of chitosans, provides access to a library of HA/CHI LbL films for tailored, diversified applications.

Multivisceral Transplantation Rehabilitation Program-Case Report.

Multivisceral transplantation is the treatment for multiple abdominal organ failure. The patient experiences reduced food intake and absorption of nutrients, contributing to weight loss and decreased muscle mass, reducing functional capacity. A physical and nutritional rehabilitation program based on adequate caloric intake associated with supervised physical exercise seems to support a gain of muscle mass, re-establishing its capacity and functional independence. A rehabilitation program was carried out, consisting of low-intensity aerobic exercise on treadmill, exercises of global strengthening (50% of 1 maximum repetition [1RM], with progressive increase), and nutritional monitoring (oral hypercaloric diet, hyperproteic supplementation daily and after exercise). Initial and final evaluation included weight, muscle mass index, brachial circumference (BC), tricipital cutaneous fold (TCF), hand grip strength (HGS), 6-minute walk test (6MWT), 1RM, vital capacity (VC), and respiratory muscle strength. After the program, functional capacity was evaluated through the 6MWT (92%), 1RM test, VC (55%), respiratory muscle strength, HGS at 5 kg, weight gain (4.75%), increase of BC in 2 cm, and TCF in 2 mm. The program contributed to functional independence, improved quality of life, and social reintegration, suggesting the importance of a supervised physical activity program associated with adequate nutritional intake after multivisceral transplantation.

Time of Dropout From the Liver Transplant List in Patients With Hepatocellular Carcinoma: Clinical Behavior According to Tumor Characteristics and Severity of Liver Disease.

BACKGROUND: Prolonged time on the waiting list affects post-transplant survival of patients with hepatocellular carcinoma (HCC). However, it is not yet known which patients will be at higher risk for early dropout from the list. We investigate specific risk factors for early waiting list dropout in patients with HCC. METHODS: This was a single-center, intention-to-treat analysis of adults with HCC, within the Milan criteria, from July 2006 through September 2013. Patients were divided into groups according to waiting list time. The main end point was dropout from the list. RESULTS: The dropout rates of the study cohort at 3, 6, and 12-months were 6.4%, 12.4%, and 17.7%, respectively. Patients who dropped out from the list tended to be older, with blood types A and O, and with higher Child-Pugh and Model for End-Stage Liver Disease (MELD) scores. They also had larger nodules, responded poorly to trans-arterial chemo-embolization (TACE), and had a higher alpha-fetoprotein. Those with blood types B and AB appeared to be protected for dropout (odds ratio [OR] = 0.21, P = .02). Patients who responded to TACE were also protected (OR = 0.22, P < .001). When we looked into time to dropout, the only baseline characteristic that stood out was a higher MELD score (13 for those dropping out up to 90 days vs 10 for those dropping out after 180 days, P = .0025). CONCLUSIONS: We conclude that patients who drop out early from the list are primarily driven by the severity of liver disease. Patients who had progressive HCC had a high tumor load and poor response to loco-regional therapies, dropping out from the list after 180 days of inclusion.

O uso do peritônio de paca conservado em solução supersaturada de açúcar a 300 por cento ou glicerina a 98 por cento implantados na parede abdominal de ratos / The use of paca peritoneum preserved in supersaturated sugar solution 300 percent or glycerine 98 percent implanted in the abdominal wall of rats

Na busca de material biológico alternativo para a realização de implantes, objetivou-se com o presente estudo avaliar comparativamente a implantação do peritônio de paca, uma nova opção de biomaterial, conservado em solução supersaturada de açúcar a 300 por cento e conservado em glicerina a 98 por cento na parede abdominal de ratos Wistar. Foram utilizados 60 ratos, machos, da linhagem Wistar, pesando entre 150 e 200 gramas, organizados nos seguintes grupos experimentais: grupo controle (GI), grupo peritônio conservado em solução supersaturada de açúcar a 300 por cento (GII) e grupo peritônio conservado em glicerina a 98 por cento (GIII), cada um com 20 animais. Os grupos GII e GIII receberam o enxerto de peritônio da paca conservado em solução de açúcar 300 por cento e glicerina 98 por cento, respectivamente, e o grupo GI não recebeu a membrana. Cinco ratos de cada grupo foram submetidos à eutanásia em quatro momentos distintos: sete, 15, 30 e 60 dias de pós-operatório para avaliações macroscópicas e microscópicas da interface implante-tecido nativo. Apesar de reações adversas observadas em 57,5 por cento dos animais do grupo GII e GIII, em 95 por cento dos animais desses grupos houve boa cicatrização da membrana. Na análise histológica, verificou-se a presença de grande infiltrado inflamatório nos períodos iniciais (sete e 15 dias) e grande presença de tecido conjuntivo nos momentos finais (30 e 60 dias). Concluiu-se que o peritônio da paca como membrana biológica conservado nos meios estudados pode ser utilizado com segurança na parede abdominal de ratos; ainda, que sua conservação em solução supersaturada de açúcar a 300 por cento permitiu melhor maleabilidade no ato cirúrgico...

In the search for alternative biological material to perform implants, this study aimed to compare the implantation of paca peritoneum, a new biomaterial option, preserved in supersaturated sugar solution 300 percent and preserved in glycerin 98 percent in the abdominal wall of Wistar rats. A total of 60 male rats from the Wistar strain weighing between 150 and 200 grams were housed into three different experimental groups: control group (GI), peritoneum preserved in supersaturated sugar solution 300 percent group (GII) and peritoneum preserved in glycerin 98 percent group (GIII), with 20 animals each. The GII and GIII received the paca peritoneum graft preserved in sugar solution 300 percent and glycerin 98 percent, respectively and group GI did not receive any membrane. Five rats from each group were euthanized at four different times: seven, 15, 30 and 60 days post-surgery for macroscopic and microscopic evaluations in graft-native tissue interface. Despite the adverse reactions observed in 57.5 percent of GII and GIII, there was good healing of the membrane in 95 percent of the animals in these groups. Upon histological examination there was a large presence of inflammatory infiltrates in the initial periods (seven and 15 days) and a large presence of connective tissue in the final stages (30 and 60). It was concluded that the paca peritoneum as biological membrane preserved as presented in this study can be used safely in the abdominal wall of rats, the preservation in supersaturated sugar solution 300 percent allowed better flexibility during surgery...

Estrutura, ultraestrutura e morfometria da aorta de paca (Cuniculus paca, Linnaeus, 1766) criada em cativeiro / Structure, ultrastructure and morphometry of the aorta in the paca (Cuniculus paca, Linnaeus, 1766) raised in captivity

Descreveram-se a morfologia, morfometria e ultraestrutura de segmentos das porções torácica e abdominal da aorta de quatro pacas (Cuniculus paca) adultas. Os segmentos aórticos foram analisados à microscopia de luz e à microscopia eletrônica de varredura. Mensuraram-se as espessuras do complexo formado pelas túnicas íntima e média, além da túnica adventícia. Os valores referentes à espessura do complexo formado pelas túnicas íntima e média da aorta torácica cranial foram significativamente maiores (média: 702,19µm) que os valores de outros segmentos aórticos analisados (médias: 354,18µm; 243,55µm). As camadas das paredes do vaso apresentaram variações entre si quanto à estrutura e espessura, supostamente em razão de adaptação à exigência funcional.

The aim of this study was to describe the morphology, morphometry and ultrastructure of segments of thoracic and abdominal aorta portions in four male and female paca (Cuniculus paca). Parts of the segments were examined by light microscopy and part by scanning electron microscopy. Thickness measurements of the tunica intima and media complex and tunica adventitia of the aorta were taken. In all animals the thickness values for the tunica intima and media complex of the cranial thoracic aorta were significantly higher (mean: 702.19µm) when compared to the values of other aortic segments analyzed (means: 354.18µm; 243.55µm). The layers of the vessel walls show variations in structure and thickness, presumably due to an adaptation to functionaldemand.

Application of the mammalian glyceraldehyde-3-phosphate dehydrogenase gene for sample quality control in multiplex PCR for diagnosis of leishmaniasis

Leishmaniasis is a neglected disease endemic in five continents. It is a severe disease that may lead to death, and its early detection is important to avoid severe damage to affected individuals. Molecular methods to detect Leishmania are considered alternatives to overcome the limitations presented by conventional methods. The aim of this study was to develop multiplex PCR systems able to detect small amounts of target DNA of Leishmania infantum and Leishmania braziliensis, and the gene coding for glyceraldehyde-3-phosphate dehydrogenase (G3PD) in mammals, enabling quality evaluation of the sample simultaneously with detection of the specific target. The systems created for G3PD recognition were combined with detection systems for L. infantum and L. braziliensis to compose multiplex PCR systems for visceral (mVL) and cutaneous (mACL) leishmaniasis diagnosis. The multiplex PCR systems developed were assessed in blood samples from five different species of mammal reservoirs involved in the disease cycle in Brazil, and 96 and 52 human samples from patients with suspected visceral leishmaniasis (VL) and cutaneous leishmaniasis (ACL), respectively. Three G3PD detection systems were created (G3PD1, G3PD2 and G3PD3) with different product sizes, G3PD2 was chosen for the formation of multiplex PCR systems. The two multiplex PCR systems (mVL and mACL) were reproducible in all species evaluated. Results of test samples (sensitivity, specificity and efficiency) suggest its use in routine diagnosis, research activities in medicine and veterinary medicine. Additionally, the systems designed to detect the G3PD gene are capable of combining with other targets used for molecular diagnosis of infectious diseases. Concerning leishmaniasis, the multiplex PCR systems can be used in epidemiological studies for the detection of new and classic reservoirs, which may contribute to the reliability of results and development of actions to control the disease.(AU)

Results of retransplantation for primary nonfunction in a single center.

INTRODUCTION: Early graft dysfunction has a negative impact on allograft and patient survivals, evolving to retransplantation or death in the majority of cases. The outcome of a second liver transplant is usually worse than the first procedure. Considering the increasing number of recipients on the waiting list, and the discrepancy between the number of accessible donors and recipients, we sought to analyze the results of retransplantation at our institution and at those within the State of Sao Paulo. METHODS: We reviewed the data of 419 deceased donor transplants on 367 patients from June 2005 to April 2010. Twenty-three patients underwent retransplantation due primary nonfunction (PNF) or early graft dysfunction. The following variables were studied: age, gender, disease that lead to the first transplant, Model for End-Stage Liver Disease (MELD) score on the day before the retransplantation, intensive care unit (ICU) length of stay, and duration of orotracheal intubation (OTI). We compared our patient survival at 30 days and 1 year with that of other patients undergoing retransplantation due to PNF in the Sao Paulo State during the same period. RESULTS: The majority of patients were females (60.87%), with a mean age of 44.6 years. The etiology that led to our first transplantation was cirrhosis due to hepatitis C virus (HCV; n = 6), followed by acute liver failure, (n = 5). The average of ICU stay was 15.08 days (range, 5-45). The mean MELD score was 34.43 (range, 19-50). The survival was 73.92% and 60.78% at 30 days and 1 year postretransplantation, respectively, whereas for São Paulo State, it was 63.04% and 51.63%, respectively.

Analysis of liver transplantation outcome in patients with MELD Score > or = 30.

Since July 2006, the liver graft allocation has been changed from the waiting time to the Model for End-stage Liver Disease (MELD), prioritizing the sickest patients, who have a higher risk of dying on the waiting list, and sometimes in such poor clinical condition that it compromises transplantation outcomes. The aim of this study was to analyze the impact of a MELD score > or = 30 on 30-day survival after liver transplantation (OLT). We prospectively collected the data on 178 liver transplants on 163 patients performed from March 2003 to August 2007. The subjects were divided in two groups according to their MELD scores: group 1, MELD > or = 30 (n = 15) and group 2, MELD < 30 (n = 96). The groups were compared with regard to hospital and intensive care unit (ICU) length of stay, intraoperative blood products transfusion, early survival (30 days), and need for retransplantation. We excluded, patients with prioritization criteria, those receiving extra points for any special situation, and six other patients without significant data for MELD calculation (of whom only one has died after transplantation). Patients under a "special situation" were those with hepatocelular carcinoma, hepatopulmonary syndrome, and metabolic diseases, who initially received a MELD/PELD score 20, and 24, and 29. The mean MELD score at group I was 34 (range, 30 to 42), and for group II it was 16 (range, 6 to 29). Group I displayed a mean hospital length of stay of 24 days (4 to 155), with 12.60 days (ranges, 1 to 103) in the ICU versus 15.55 (range, 1 to 48) and 5.13 (range, 1 to 45) days, respectively, for group II. The need for blood component transfusions were greater in group I; 25.28% of patients in group II did not receive any transfusion during the entire inpatient period. There were nine retransplants in group II, and none in group I. The 30-day survivals were 93.3% for group I and 84.37% for group II. Besides the increased complexity of these sickest patients, there was no negative impact on early survival rates.

Impact of cumulative risk factors for expanded criteria donors on early survival after liver transplantation.

There are various options to help overcome the organ shortage, including performing transplants using grafts from marginal donors with characteristics previously described as unacceptable because of the high risk of graft failure. Nowadays, expanded criteria donors for liver transplantation (OLT) is a strategy used routinely by many teams. Some donor features have been suggested to jeopardize initial function or survival; when these features are aggregated, they may impact prognosis. The aim of this study was to evaluate the impact of donor risk factors on early patient survival and retransplantation. Donor risk factors were considered to be older than 60 years, body mass index > 30, serum sodium level > 155 mEq/L, cold ischemia time > 12 hours, and intensive care unit stay > 4 days. We prospectively recorded data from 139 patients who underwent 152 OLT from March 2003 to May 2007. Patients were classified into four groups: I, no risk factors; II, one risk factor; III, two risk factors; IV, three or more risk factors. Retransplantation or OLT due to acute liver failure was considered to be an exclusion criterion. Early overall survival rate was 83.76%; 12 retransplantations were required (10.25%). Comparing the four groups, patient survivals (P = .41) and retransplantation rates (P = .518) were similar. In conclusion, cumulative risk factors showed no impact on early (30-day) recipient survival and or on the necessity of retransplantation after OLT.

Impact of renal failure on liver transplantation survival.

Renal failure after orthotopic liver transplantation (OLT) is a common complication (ranging from 12% to 70%) associated with worse outcomes, particularly when it requires renal replacement therapy (RRT). Renal dysfunction is a common scenario among waiting list patients. It can lead to a worse prognosis after OLT, due to an increased incidence of postoperative renal failure. The aim of this study was to analyze the incidence of renal failure after OLT, its relationship to pretransplant renal dysfunction, and its impact on outcomes. We analyzed data collected prospectively from 152 consecutive OLTs in 139 patients performed by the same team from March 2003 to November 2007. Exclusion criteria for 34 cases included transplantation due to acute liver failure, combined liver-kidney transplantation, retransplantation, and patients who died up to 2 days posttransplantation. Based on creatinine clearance (CCr) calculated at the time of OLT, the 118 patients were classified in two groups: group I, normal pre-OLT renal function (CCr > or = 70 mL/min) versus group II, pre-OLT renal failure (CCr < 70 mL/min). Each group was analyzed according to the development of post-OLT renal failure, being classified as subgroup A (normal renal function post-OLT), subgroup B (mild renal impairment post-OLT-serum creatinine level between 2.0 and 3.0 mg/dL or doubled basal value up to 3.0 mg/dL) versus subgroup C (severe renal impairment post-OLT-serum creatinine level > or = 3.0 mg/dL or utilization of RRT). The overall incidence of post-OLT renal impairment was 41.52% with RRT in 22 patients (18.64%). Group II patients showed a greater incidence of post-OLT renal failure when compared with other patients (P < .05), but without a statistical difference when compared according to RRT requirement. Comparison of average hospital stay was similar between groups I and II, and also among its subgroups (A, B, and C, respectively). There was no statistical difference in early (30-day) and 1-year survival rates between groups I and II. Comparing all subgroups for early and 1-year survival, we observed that patients who developed severe renal failure post-OLT (subgroups I-C and II-C) showed worse outcomes compared with other patients (subgroups I-A, I-B, II-A, and II-B), respectively 95.29% versus 69.69% and 86.95% versus 41.66% for early and 1-year survivals (P < .001). In conclusion, our findings suggested that patients who developed severe renal failure post-OLT, independent of pretransplant renal function, showed worse outcomes.

Total hepatectomy and liver transplantation as a two-stage procedure for toxic liver: case reports.

Total hepatectomy with temporary portocaval shunt was employed as a bridging procedure before liver transplantation, in the setting of fulminant hepatic failure with "toxic liver syndrome"; acute, severe, and extensive liver necrosis associated with cardiovascular shock and acute renal failure with or without respiratory failure. This procedure sought to improve metabolic acidosis and hemodynamic instability related to advanced liver necrosis. The aim of this study was to report our experience with three patients who underwent total hepatectomy and protocaval shunt, followed by liver transplantation (two-stage procedure).

Antibody-mediated rejection: hyperacute rejection reality in liver transplantation? A case report.

Hyperacute rejection is rare among ABO-compatible liver transplantations. The mechanism is donor preformed antibodies causing graft loss within a few days. Herein, we have described a case of an ABO-compatible liver transplantation that underwent hyperacute rejection, needing retransplantation for treatment. A 27-year-old man of blood group A positive who displayed fulminant hepatic failure due to hepatitis B (in agreement with the O'Grady criteria), received an ABO-compatible graft. He developed significant asthenia, fever, hypotension, oliguria, and coagulopathy. Ultrasonography revealed total thrombosis of the portal vein and absence of dilatation of bile ducts. The patient was priorized for retransplantation and underwent a good subsequent evolution. On anatomopathologic exam the explant revealed thrombosis of the intrahepatic branches of the portal vein with venous and ischemic infarcts compatible with a diagnosis of hyperacute rejection. The clinical findings of hyperacute rejection were characterized by progressive elevation of bilirubin and thrombocytopenia associated with signs of hepatic failure during the first days after transplantation. In this case, the histological exam was compatible with hyperacute rejection, excluding the diagnoses of hepatic artery thrombosis or biliary obstruction, despite the negative test for anti-HLA antibodies. The diagnosis of hyperacute rejection could be made associated with a short ischemic time and a good response after retransplantation.

Analysis of Model for End-Stage Liver Disease (MELD) score in a liver transplantation waiting list.

BACKGROUND: The Model for End-Stage Liver Disease (MELD) was introduced in 1999 to quantify the 3-month prognosis of cirrhotic patients after a transjugular intrahepatic portosystemic shunt (TIPS). Because of the imbalance between organ donors and patients on the waiting list, the MELD was adopted by the United States in 2002 to allocate liver grafts for transplantation. Preliminary results have indicated a reduction in waiting list deaths and an increase in transplantation rates for candidates. Seeking to find a new model to predict death on the waiting list and after liver transplantation, retrospective studies have examined MELD scores in waiting list patients. The aim of this study was to analyze the MELD scores of patients on the liver waiting list for comparisons between transplanted patients. PATIENTS AND METHODS: A retrospective study was performed analyzing 131 registrations of 127 orthotopic liver transplant (OLT) patients (4 underwent retransplantation) grafted between November 2000 and January 2006, excluding 24 patients: 2 had urgent retransplantations due to hepatic artery thrombosis and 22 had incomplete data. These patients were divided into 3 groups: group I (transplanted patients)-53 patients underwent 55 OLT; group II-29 patients who died on the waiting list; group III-patients on the waiting list including 23 patients still waiting as of the date of the study. RESULTS: The main indication for OLT was hepatitis C virus cirrhosis (50.50%), followed by alcoholic liver cirrhosis (23.30%), cryptogenic cirrhosis (12.60%), autoimmune hepatitis (5.80%), hepatitis B virus cirrhosis (4.85%), and primary biliary cirrhosis (2.91%). Group I: MELD score 15.62 (range, 6-39) on admission to the list, and 18.87 (range, 7-39) at transplantation. The mean waiting time for OLT was 478.39 days (range, 2-1270 days). The 38 patients who survived underwent 39 OLT (1 retransplantation). The MELD score at entrance to the list was 14.62 (range, 7-30) and at transplantation, 17.70 (range, 7-39). The mean time between admission to the list and transplantation was 505.37 days (range, 6-1270 days). The 15 patients who died had received 16 OLT (1 retransplantation). Their MELD scores were 17.80 (range, 6-39) and 21.81 (range, 9-39) at admission to the list and at transplantation, respectively, with a mean time on the waiting list of 417.93 days (range, 2-872 days). Group II: 29 patients died before OLT, at a mean age of 52.60 years (range, 22-67 years). Their MELD score was 19.24 (range, 7-45), and the interval between admission to the waiting list and death was 249.55 days (range, 3-1247 days). Group III: 23 patients still active on the OLT waiting list at the time of study displayed a mean MELD score of 13.65 (range, 6-28) and 354.30 days (range, 2-905 days) waiting until the moment. In conclusion, MELD score at the time of admission to the waiting list was higher among those patients who died either awaiting a liver graft (19.24) or after OLT (17.80) compared with those who survived after OLT (14.60) or are still awaiting OLT (13.65).

Donor liver dysfunction: application of a new scoring system to identify the marginal donor.

Livers from marginal donors are increasingly used for transplantation due to the shortage of donor organs. The definition of a marginal donor remains unclear; prediction of organ function is a challenge. In the literature the use of steatotic livers has been associated with poor liver function or even primary dysfunction of the allograft. Tekin et al created a scoring system that classifies a donor as marginal or nonmarginal, using a mathematical model based on donor age and steatosis degree. The aims of this study were to apply the Tekin method to identify marginal and nonmarginal donors and evaluate the influence of the cold ischemia time (CIT) on allograft evolution. We retrospectively reviewed deceased donor liver transplantations performed from October 1995 to March 2006, namely, 177 adult liver transplantations in 163 patients. Fifty-five were excluded due to retransplantation (14) or insufficient data (41). Donor age and macrovesicular steatosis were evaluated according to the mathematical formula proposed by Tekin et al, classifying the donors as marginal versus nonmarginal. The authors also analyzed the CIT, 3-month mortality, and development of primary nonfunction or primary dysfunction. The median donor age was 38.9 years (range, 6-71). The postreperfusion biopsy specimen showed moderate to intense steatosis (>30%) in 14.75% of specimens, with no steatosis or mild steatosis in 85.25%. Sixty-one grafts (50%) developed primary graft dysfunction (PGD): 10 grafts, with primary nonfunction (PNF); and 51 with initial poor function (IPF). Using the criteria provided by Tekin et al, we obtained 41 marginal and 81 nonmarginal allografts. The marginal group showed 61.9% PGD, compared with 59.2% of PGD by the nonmarginal group. The CIT was greater than 12 hours in 5 marginal group transplants and 4 PGD cases (80%). Of the nonmarginal allografts, the CIT was greater than 12 hours in 29.6%, with 75% PGD. The 3-month graft survival rate was 80% in the marginal group with ischemia time more than 12 hours: 86.1% of the same group when CIT was less than 12 hours, and 82.7% in the nonmarginal group. In contrast, when we analyzed the occurrence of allograft dysfunction, the 3-month mortality rate was 34% among, grafts with dysfunction, whereas, in those without initial dysfunction, it was 4.1%. In conclusion, the score suggested by Tekin et al that classifies the donors as ideal (nonmarginal) or marginal was not able to predict initial primary dysfunction.

Results of urgent liver retransplantation in the state of São Paulo, Brazil.

The treatment of end-stage liver disease includes transplantation as a life-saving procedure although it has serious complications of hepatic artery thrombosis, liver dysfunction, or primary nonfunction, which frequently lead to the need for retransplantation. According to various reports, the incidence of retransplantation is around 10%. Given the critical organ shortage, the chance for a second transplant remains a controversial discussion in medical, ethical, and economic grounds because patient and graft survival rates after retransplantation are lower than those for primary transplantations. We retrospectively reviewed all of the urgent liver retransplants from October 2001 to February 2005 (52 months) by analyzing the number of retransplants, blood group, time between first and second liver transplantation, age, sex, and mortality. Data were obtained from the Transplantation System, State of Sao Paulo Health Secretariat. Among 1252 liver transplants performed during this period, 98 (7.82%) were urgent retransplantations. The primary procedure employed 955 (76.28%) deceased donors and 297 (23.72%) living donors. All 98 retransplants were performed using an organ from the pool of deceased donors. The retransplant rate was acceptable according to the literature, although we observed high rates of early mortality (<60 days), leading to a discussion of which patients had a better chance of survival and the best time to perform the second transplantation to use this scarce and precious resource in the best possible way.

Surface-relief gratings and photoinduced birefringence in layer-by-layer films of chitosan and an azopolymer.

Layer-by-layer (LBL) films of chitosan alternated with an azopolymer, PS119, have been used for optical storage and fabrication of surface-relief gratings. The optical properties stem from the trans-cis-trans isomerization cycles undergone by the azochromophore, with a kinetics for writing the birefringence pattern that is much slower than in the spin-coated or cast films of azopolymers. The long writing times, of the order of 100 s, are due to the electrostatic interactions between adjacent chitosan and PS119 layers. Such interactions are also responsible for other features in the LBL films, namely the increase in the amount of adsorbed material when the pH of the preparation solution is decreased and the large residual birefringence after the writing laser is switched off. Gratings could be inscribed with s-polarized but not with p-polarized light, indicating a mass transport process associated with photodegradation.

Lutzomyia naftalekatzi, a new species of phlebotomine sand fly (Diptera: Psychodidae) from Zona da Mata region, Pernambuco, Brazil.

Lutzomyia naftalekatzi, a new phlebotomine sand fly belonging to the L. aragaoi species group, is described from specimens collected in Zona da Mata region of Pernambuco, Brazil.

Domesticity of Lutzomyia whitmani (Diptera: psychodidae) populations: field experiments indicate behavioural differences.

The sandfly Lutzomyia whitmani (Antunes & Coutinho) is an important vector for cutaneous leishmaniasis throughout much of Brazil, and has recently been shown to consist of more than one mitochondrial lineage. It has frequently been asserted that the degree of adaptation of L. whitmani to human environments varies across its range. As a standardized test of indoor feeding for three geographically distant populations of L. whitmani, catches inside experimental chicken sheds of varying degrees of wall closure (0%, 33%, 67% and 98%) were compared. Each increment in shed closure reduced catches of females (relative to the most open shed) by a similar degree for each population: geometric mean catches dropped by 11-40% with 33% closure, by 41-62% with 67% closure, and by 69-100% with 98% closure. Geometric mean catches of males from the two more northerly populations also decreased with increasing shed closure, by 18% and 22% for 33% closure, 58% and 69% for 67% closure, 91% and 93% for 98% closure. Males from the most southerly population showed significantly different behaviour, with 33% closure causing a 54% increase in geometric mean catch, 67% closure causing a 6% increase, and 98% closure causing a 32% reduction. For this southerly population, sex ratios became more male biased with increasing density in more closed sheds, suggesting aggregation driven by intra-specific communication. Lutzomyia intermedia (Lutz & Neiva) was relatively more likely than L. whitmani to approach baits in the three more closed sheds, rather than the most open shed, offering a behavioural explanation for observed differences in indoor biting rates between the species.