Role of albumin in the metabolism and excretion of ochratoxin A.

Ochratoxin A (OTA) is known to be strongly bound to serum albumin, but it remains unknown how albumin affects its metabolism and kinetics. To close this gap, we used a mouse model, where heterozygous albumin deletion reduces serum albumin to concentrations similar to hypoalbuminemic patients and completely eliminates albumin by a homozygous knockout. OTA and its potential metabolites (OTα, 4-OH-OTA, 7'-OH-OTA, OTHQ, OP-OTA, OTB-GSH, OTB-NAC, OTB) were time-dependently analyzed in plasma, bile, and urine by LC-MS/MS and were compared to previously published hepatotoxicity and nephrotoxicity data. Homozygous albumin deletion strongly accelerated plasma clearance as well as biliary and urinary excretion of the parent compound and its hydroxylation products. Decreasing albumin in mice by the heterozygous and even more by the homozygous knockout leads to an increase in the parent compound in urine which corresponded to increased nephrotoxicity. The role of albumin in OTA-induced hepatotoxicity is more complex, since heterozygous but not homozygous nor wild-type mice showed a strong biliary increase in the toxic open lactone OP-OTA. Correspondingly, OTA-induced hepatotoxicity was higher in heterozygous than in wild-type and homozygous animals. We present evidence that albumin-mediated retention of OTA in hepatocytes is required for formation of the toxic OP-OTA, while complete albumin elimination leads to rapid biliary clearance of OTA from hepatocytes with less formation of OP-OTA. In conclusion, albumin has a strong influence on metabolism and toxicity of OTA. In hypoalbuminemia, the parent OTA is associated with increased nephrotoxicity and the open lactone with increased hepatotoxicity.

Integrated data from intravital imaging and HPLC-MS/MS analysis reveal large interspecies differences in AFB1 metabolism in mice and rats.

Large interspecies differences between rats and mice concerning the hepatotoxicity and carcinogenicity of aflatoxin B1 (AFB1) are known, with mice being more resistant. However, a comprehensive interspecies comparison including subcellular liver tissue compartments has not yet been performed. In this study, we performed spatio-temporal intravital analysis of AFB1 kinetics in the livers of anesthetized mice and rats. This was supported by time-dependent analysis of the parent compound as well as metabolites and adducts in blood, urine, and bile of both species by HPLC-MS/MS. The integrated data from intravital imaging and HPLC-MS/MS analysis revealed major interspecies differences between rats and mice: (1) AFB1-associated fluorescence persisted much longer in the nuclei of rat than mouse hepatocytes; (2) in the sinusoidal blood, AFB1-associated fluorescence was rapidly cleared in mice, while a time-dependent increase was observed in rats in the first three hours after injection followed by a plateau that lasted until the end of the observation period of six hours; (3) this coincided with a far stronger increase of AFB1-lysine adducts in the blood of rats compared to mice; (4) the AFB1-guanine adduct was detected at much higher concentrations in bile and urine of rats than mice. In both species, the AFB1-glutathione conjugate was efficiently excreted via bile, where it reached concentrations at least three orders of magnitude higher compared to blood. In conclusion, major differences between mice and rats were observed, concerning the nuclear persistence, formation of AFB1-lysine adducts, and the AFB1-guanine adducts.

Acetaminophen overdose causes a breach of the blood-bile barrier in mice but not in rats.

Acetaminophen (APAP) is known to cause a breach of the blood-bile barrier in mice that, via a mechanism called futile bile acid (BA) cycling, increases BA concentrations in hepatocytes above cytotoxic thresholds. Here, we compared this mechanism in mice and rats, because both species differ massively in their susceptibility to APAP and compared the results to available human data. Dose and time-dependent APAP experiments were performed in male C57BL6/N mice and Wistar rats. The time course of BA concentrations in liver tissue and in blood was analyzed by MALDI-MSI and LC-MS/MS. APAP and its derivatives were measured in the blood by LC-MS. APAP-induced liver damage was analyzed by histopathology, immunohistochemistry, and by clinical chemistry. In mice, a transient increase of BA in blood and in peri-central hepatocytes preceded hepatocyte death. The BA increase coincided with oxidative stress in liver tissue and a compromised morphology of bile canaliculi and immunohistochemically visualized tight junction proteins. Rats showed a reduced metabolic activation of APAP compared to mice. However, even at very high doses that caused cell death of hepatocytes, no increase of BA concentrations was observed neither in liver tissue nor in the blood. Correspondingly, no oxidative stress was detectable, and the morphology of bile canaliculi and tight junction proteins remained unaltered. In conclusion, different mechanisms cause cell death in rats and mice, whereby oxidative stress and a breach of the blood-bile barrier are seen only in mice. Since transient cholestasis also occurs in human patients with APAP overdose, mice are a clinically relevant species to study APAP hepatotoxicity but not rats.

A liver digital twin for in silico testing of cellular and inter-cellular mechanisms in regeneration after drug-induced damage.

This communication presents a mathematical mechanism-based model of the regenerating liver after drug-induced pericentral lobule damage resolving tissue microarchitecture. The consequence of alternative hypotheses about the interplay of different cell types on regeneration was simulated. Regeneration dynamics has been quantified by the size of the damage-induced dead cell area, the hepatocyte density and the spatial-temporal profile of the different cell types. We use deviations of observed trajectories from the simulated system to identify branching points, at which the systems behavior cannot be explained by the underlying set of hypotheses anymore. Our procedure reflects a successful strategy for generating a fully digital liver twin that, among others, permits to test perturbations from the molecular up to the tissue scale. The model simulations are complementing current knowledge on liver regeneration by identifying gaps in mechanistic relationships and guiding the system toward the most informative (lacking) parameters that can be experimentally addressed.

Role of Serine arginine protein kinase 1 and Minichromosome maintenance protein 2 in predicting epithelial ovarian cancer response to treatment and prognosis.

BACKGROUND: Serine-Arginine (SR) proteins are a conserved family of proteins involved in RNA splicing and are reported to be over-expressed in multiple cancers. The aim of the study is evaluation of the expression of Serine arginine protein kinase 1 (SRPK1) and Minichromosome maintenance protein 2 (MCM2) in epithelial ovarian cancer (EOC) and their correlation with clinicopathological features, response to therapy, progression-free survival (PFS), and cancer-specific survival (CSS). METHODS: This study was carried out on surgical specimens of 65 patients diagnosed with EOC which were submitted to immunohistochemical staining by SRPK1 and MCM2 antibodies. RESULTS: About 89.2% of cases showed SRPK1 expression and its high expression was significantly associated with type II tumors and advanced stage. All cases showed nuclear immunoreaction for MCM2 with high expression in 49.2% of cases. There was a significant relationship between high values of SRPK1 H-score and percentage of MCM2. Postmenopause, type II pathology, advanced stage, absence of complete response to the treatment, resistance to platinum-based chemotherapy, and surgery done by a general surgeon were the factors affecting PFS. Response to treatment and platinum sensitivity were the most independent factors affecting patients' PFS. The factors associated with shorter CSS were suboptimal debulking, advanced stage, absence of complete response to the treatment, platinum resistance, and high SRPK1. High SRPK1 expression and platinum sensitivity were the independent factors affecting patients' CSS. CONCLUSIONS: SRPK1 is an unfavorable biomarker in EOC patients because of its association with aggressive histologic type, advanced International Federation of Gynecology and Obstetrics (FIGO) stage, and worse survival. SRPK1 could promote the proliferation of EOC by up-regulation of MCM2.

The efficacy of various irrigation techniques on the removal of double antibiotic paste from simulated immature roots and the amount of apically extruded debris.

OBJECTIVE: This study evaluated the effect of the XP-Endo Finisher (XPF), passive ultrasonic irrigation (PUI) and conventional irrigation using side-vented needle (SVN) on the amount of apically extruded debris and canal cleanliness following the removal of double antibiotic paste (DAP) from immature root canal models. MATERIAL AND METHODS: Forty-eight extracted mandibular premolars were drilled using peeso drills to simulate immature apices. The canals were filled with DAP and were randomly assigned into 3 groups according to the DAP removal method: XPF, PUI, and SVN (n = 16). The amount of extruded debris was assessed with an analytical balance then roots were split longitudinally and imaged using stereomicroscope to evaluate the residual medicament. Data were statistically analyzed using Kruskal-Wallis and Dunn's test. Spearman's correlation coefficient was used to determine significant correlation between extruded debris and the residual DAP scores. RESULTS: There was no significant difference between debris extrusion values for all groups (P value 0.237). For canal cleanliness, the amount of remaining DAP was significantly lower in the XPF and PUI compared to SVN (P value < 0.001). A non-significant positive (direct) correlation was found between the amounts of apically extruded debris and residual DAP scores (P value 0.087). CONCLUSION: XPF and PUI were associated with better canal cleanliness during removal of DAP, no difference could be found between the three irrigation techniques regarding the debris extrusion.

Comparison of canal transportation and centering ability of Xp Shaper, WaveOne and Oneshape: a cone beam computed tomography study of curved root canals / Comparación del transporte apical y la capacidad de conservación de la anatomía del conducto de XpShaper, WaveOne y Oneshape: Estudio de conductos curvos por tomografía computarizada de haz cónico

The aim of the present study was to investigate the shaping abilities of XP Shaper and compare it with other single file rotary NiTi systems utilizing full rotation and reciprocation motion, by cone beam computed tomography. Mesiobuccal canals of fortyfive mandibular first molars, were allocated into three equal groups (n=15) according to the rotary system applied; WaveOne, OneShape and XP shaper. Preand postinstrumentation images were obtained at 3mm, 5mm and 7mm from the apex using cone beam computed tomography and assessed to determine canal transportation and centering ability. Data were analyzed using KruskalWallis test to compare the three systems and Friedman's test to compare the root levels. Results showed that WaveOne and OneShape rotary systems produced greatest mean transportation with no statistically significant difference between them, while XP Shaper produced the lowest statistically significant mean transportation. Canal centering ability differed significantly among the three systems used. It was concluded that XP shaper preserved the original canal anatomy better than WaveOne and OneShape rotary systems (AU)

El objetivo del presente trabajo fue investigar la capacidad de tallado apical de XP Shaper y compararla con dos sistemas de NiTi, rotatorio y reciprocante, mediante tomografías computarizadas de haz cónico. Se analizaron los canales mesio vestibulares de cuarenta y cinco primeros molares inferiores. Los dientes fueron divididos en tres grupos experimentales (n=15): WaveOne, OneShape and XP shaper. Se obtuvieron imágenes pre y post instrumentación a 3mm, 5mm y 7 mm del ápice utilizando tomografías computadas de haz cónico para determinar la presencia de transporte apical y la capacidad de conservación de la anatomía original del conducto. Se utilizó el test deKruskalWallis para comparar los tres sistemas de intrumentación y el test de Friedman para comparar las mediciones en los tres niveles de raíz. XP Shaper mostró la menor cantidad de transporte apical estadística mente significativa mientras que WaveOne y OneShape mostraron el mayor transporte apical sin diferencia estadística mente significativa entre los dos grupos. XP shaper permitió conservar la anatomía del canal original mejor que WaveOne y OneShape (AU)

Fatal Strongyloides stercoralis hyper-infection in a patient with multiple myeloma

Strongyloides stercoralis (S.S.) is a human intestinal parasite, which may lead to complicated strongyloidiasis. We report a case of disseminated strongyloidiasis following the treatment of myeloma. The patient developed skin lesions, respiratory distress, aseptic meningitis and bacterial and fungal sepsis. The diagnosis of strongyloidiasis was established through endotracheal tube secretions. Despite the treatment with Ivermectin and Albendazole, the outcome was fatal. The value of screening for strongyloidiasis is unclear but may be of benefit in patients with hematological malignancies from high endemic areas.