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.

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.

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.

Inhibition of the renal apical sodium dependent bile acid transporter prevents cholemic nephropathy in mice with obstructive cholestasis

BACKGROUND & AIMS

Cholemic nephropathy (CN) is a severe complication of cholestatic liver diseases for which there is no specific treatment. We revisited its pathophysiology with the aim of identifying novel therapeutic strategies.

METHODS

Cholestasis was induced by bile duct ligation (BDL) in mice. Bile flux in kidneys and livers was visualized by intravital imaging, supported by MALDI mass spectrometry imaging and liquid chromatography-tandem mass spectrometry. The effect of AS0369, a systemically bioavailable apical sodium-dependent bile acid transporter (ASBT) inhibitor, was evaluated by intravital imaging, RNA-sequencing, histological, blood, and urine analyses. Translational relevance was assessed in kidney biopsies from patients with CN, mice with a humanized bile acid (BA) spectrum, and via analysis of serum BAs and KIM-1 (kidney injury molecule 1) in patients with liver disease and hyperbilirubinemia.

RESULTS

Proximal tubular epithelial cells (TECs) reabsorbed and enriched BAs, leading to oxidative stress and death of proximal TECs, casts in distal tubules and collecting ducts, peritubular capillary leakiness, and glomerular cysts. Renal ASBT inhibition by AS0369 blocked BA uptake into TECs and prevented kidney injury up to 6 weeks after BDL. Similar results were obtained in mice with humanized BA composition. In patients with advanced liver disease, serum BAs were the main determinant of KIM-1 levels. ASBT expression in TECs was preserved in biopsies from patients with CN, further highlighting the translational potential of targeting ASBT to treat CN.

CONCLUSIONS

BA enrichment in proximal TECs followed by oxidative stress and cell death is a key early event in CN. Inhibiting renal ASBT and consequently BA enrichment in TECs prevents CN and systemically decreases BA concentrations.

IMPACT AND IMPLICATIONS

Cholemic nephropathy (CN) is a severe complication of cholestasis and an unmet clinical need. We demonstrate that CN is triggered by the renal accumulation of bile acids (BAs) that are considerably increased in the systemic blood. Specifically, the proximal tubular epithelial cells of the kidney take up BAs via the apical sodium-dependent bile acid transporter (ASBT). We developed a therapeutic compound that blocks ASBT in the kidneys, prevents BA overload in tubular epithelial cells, and almost completely abolished all disease hallmarks in a CN mouse model. Renal ASBT inhibition represents a potential therapeutic strategy for patients with CN.

Tumor resistance to anti-mesothelin CAR-T cells caused by binding to shed mesothelin is overcome by targeting a juxtamembrane epitope

Despite many clinical trials, CAR-T cells are not yet approved for human solid tumor therapy. One popular target is mesothelin (MSLN) which is highly expressed on the surface of about 30% of cancers including mesothelioma and cancers of the ovary, pancreas, and lung. MSLN is shed by proteases that cleave near the C terminus, leaving a short peptide attached to the cell. Most anti-MSLN antibodies bind to shed MSLN, which can prevent their binding to target cells. To overcome this limitation, we developed an antibody (15B6) that binds next to the membrane at the protease-sensitive region, does not bind to shed MSLN, and makes CAR-T cells that have much higher anti-tumor activity than a CAR-T that binds to shed MSLN. We have now humanized the Fv (h15B6), so the CAR-T can be used to treat patients and show that h15B6 CAR-T produces complete regressions in a hard-to-treat pancreatic cancer patient derived xenograft model, whereas CAR-T targeting a shed epitope (SS1) have no anti-tumor activity. In these pancreatic cancers, the h15B6 CAR-T replicates and replaces the cancer cells, whereas there are no CAR-T cells in the tumors receiving SS1 CAR-T. To determine the mechanism accounting for high activity, we used an OVCAR-8 intraperitoneal model to show that poorly active SS1-CAR-T cells are bound to shed MSLN, whereas highly active h15B6 CAR-T do not contain bound MSLN enabling them to bind to and kill cancer cells.

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.

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.

Altering maternal calcium and phosphorus dietary intake induces persistent sex-specific changes in the dentition of the offspring

BACKGROUND

The maternal diet is essential to offspring development, but the specific effects on tooth morphology are still unknown. The aim of this study was to evaluate the effects of altering maternal calcium (Ca) and phosphorus (P) supplementation during gestation and lactation on offspring dentition.

METHODS

Pregnant mice were fed an experimental diet containing a threefold increase in Ca and a threefold decrease in P compared to the standard mouse chow diet at embryonic Day 0.5 (E0.5). Offspring mice were maintained on standard or experimental diets from post-natal Day 0 to weaning, then fed control diets until 6 weeks of age. Six-week-old offspring heads were collected and scanned using micro-computed tomography. Dental morphometrics of offspring maxillary and mandibular first and third molars (n = 5-6 per diet/per sex) were determined. A two-way ANOVA test was employed to verify the existence of any significant differences between groups. The significance level was set at P < .05.

RESULTS

A two-way ANOVA revealed a statistically significant interaction between the effects of diet and sex on the upper and lower dentition. Moreover, experimental diet-fed female offspring exhibited smaller molars with shorter mesiodistal width and larger pulp chambers relative to controls, while experimental diet-fed male offspring possessed larger molars with wider mesiodistal width and smaller pulp chambers.

CONCLUSION

Our findings reveal that altering the maternal and offspring dietary Ca:P ratio during gestation, lactation and weaning led to significant, sex-specific changes in the offspring dentition. The differences in dentition appeared to be correlated with the sex-specific changes in the craniofacial skeleton.

Increased sinusoidal export of drug glucuronides is a compensative mechanism in liver cirrhosis of mice

Rationale: Liver cirrhosis is known to affect drug pharmacokinetics, but the functional assessment of the underlying pathophysiological alterations in drug metabolism is difficult. Methods: Cirrhosis in mice was induced by repeated treatment with carbon tetrachloride for 12 months. A cocktail of six drugs was administered, and parent compounds as well as phase I and II metabolites were quantified in blood, bile, and urine in a time-dependent manner. Pharmacokinetics were modeled in relation to the altered expression of metabolizing enzymes. In discrepancy with computational predictions, a strong increase of glucuronides in blood was observed in cirrhotic mice compared to vehicle controls. Results: The deviation between experimental findings and computational simulations observed by analyzing different hypotheses could be explained by increased sinusoidal export and corresponded to increased expression of export carriers (Abcc3 and Abcc4). Formation of phase I metabolites and clearance of the parent compounds were surprisingly robust in cirrhosis, although the phase I enzymes critical for the metabolism of the administered drugs in healthy mice, Cyp1a2 and Cyp2c29, were downregulated in cirrhotic livers. RNA-sequencing revealed the upregulation of numerous other phase I metabolizing enzymes which may compensate for the lost CYP isoenzymes. Comparison of genome-wide data of cirrhotic mouse and human liver tissue revealed similar features of expression changes, including increased sinusoidal export and reduced uptake carriers. Conclusion: Liver cirrhosis leads to increased blood concentrations of glucuronides because of increased export from hepatocytes into the sinusoidal blood. Although individual metabolic pathways are massively altered in cirrhosis, the overall clearance of the parent compounds was relatively robust due to compensatory mechanisms.

Vinpocetine protects against chloroquine-induced cardiotoxicity by mitigating oxidative stress

Chloroquine (CQ) and hydroxychloroquine (HCQ) are classical antimalarial drugs, and recently have been used for other applications including coronavirus disease 2019 (COVID-19). Although they are considered safe, cardiomyopathy may associate CQ and HCQ applications particularly at overdoses. The goal of the present study was to evaluate the potential protective effect of the nootropic agent vinpocetine against CQ and HCQ adverse effects with a specific focus on the heart. For this purpose, a mouse model of CQ (0.5 up to 2.5 g/kg)/HCQ (1 up to 2 g/kg) toxicity was used, and the effect of vinpocetine was evaluated by survival, biochemical, as well as histopathological analyses. Survival analysis revealed that CQ and HCQ caused dose-dependent lethality, which was prevented by co-treatment with vinpocetine (100 mg/kg, oral or intraperitoneal). To gain deeper understanding, a dose of 1 g/kg CQ-which did not cause death within the first 24 h after administration-was applied with and without vinpocetine administration (100 mg/kg, intraperitoneal). The CQ vehicle group showed marked cardiotoxicity as evidenced by significant alterations of blood biomarkers including troponione-1, creatine phosphokinase (CPK), creatine kinase-myocardial band (CK-MB), ferritin, and potassium levels. This was confirmed at the tissue level by massive alteration of the heart tissue morphology and coincided with massive oxidative stress. Interestingly, co-administration of vinpocetine strongly ameliorated CQ-induced alterations and restored the antioxidant-defense system of the heart. These data suggest that vinpocetine could be used as an adjuvant therapy together with CQ/HCQ applications.

Cognitive Functions, Neurotransmitter Alterations, and Hippocampal Microstructural Changes in Mice Caused by Feeding on Western Diet

Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) is the most common chronic liver disease in Western countries. It is becoming increasingly evident that peripheral organ-centered inflammatory diseases, including liver diseases, are linked with brain dysfunctions. Therefore, this study aims to unravel the effect of MASLD on brain histology, cognitive functions, and neurotransmitters. For this purpose, mice fed for 48 weeks on standard (SD) or Western diet (WD) were evaluated by behavioral tests, followed by sacrifice and analysis of the liver-brain axis including histopathology, immunohistochemistry, and biochemical analyses. Histological analysis of the liver showed features of Metabolic Dysfunction-Associated Steatohepatitis (MASH) in the WD-fed mice including lipid droplet accumulation, inflammation, and fibrosis. This was accompanied by an elevation of transaminase and alkaline phosphatase activities, increase in inflammatory cytokine and bile acid concentrations, as well as altered amino acid concentrations in the blood. Interestingly, compromised blood capillary morphology coupled with astrogliosis and microgliosis were observed in brain hippocampus of the WD mice, indicating neuroinflammation or a disrupted neurovascular unit. Moreover, attention was impaired in WD-fed mice along with the observations of impaired motor activity and balance, enhanced anxiety, and stereotyped head-twitch response (HTR) behaviors. Analysis of neurotransmitters and modulators including dopamine, serotonin, GABA, glutamate, and acetylcholine showed region-specific dysregulation in the brain of the WD-fed mice. In conclusion, the induction of MASH in mice is accompanied by the alteration of cellular morphology and neurotransmitter expression in the brain, associated with compromised cognitive functions.

Effect of continuous chelation on the dentinal tubule penetration of a calcium silicate-based root canal sealer: a confocal laser microscopy study

BACKGROUND

This study aimed to evaluate the effect of various irrigation protocols on the penetration depth of a calcium silicate-based sealer into dentinal tubules using confocal laser scanning microscopy (CLSM).

METHODS

Twenty single-rooted mandibular premolars were endodontically prepared and divided into the following two groups according to the irrigation protocol used (n = 10): Group I: NaOCl + EDTA and Group II: continuous chelation (NaOCl/Dual Rinse). Obturation was performed with the warm vertical compaction technique using TotalFill HiFlow bioceramic sealer mixed with a fluorophore dye. Samples were observed using CLSM at 10× to measure the percentage of sealer penetration and its maximum depth into the dentinal tubules. Data were analysed using one-way ANOVA followed by Tukey's post-hoc test. The significance level was set at p < 0.05 within all tests.

RESULTS

Comparing the overall results of all sections tested, no statistically significant differences existed between the groups regarding the percentage of sealer penetration (p = 0.612) and maximum depth of penetration (p > 0.05).

CONCLUSIONS

With both types of irrigation used, dentinal tubule penetration was higher in the coronal section than in the apical section. Continuous chelation using NaOCl/Dual Rinse HEDP performed better in the coronal segments, while irrigation using NaOCl + EDTA promoted a higher percentage of sealer penetration in the apical segment.

Proficiency of some synthetic alginate derivatives for sequestration of Iodine-131 from radioactive liquid waste

The current effort in environmental remediation is aimed at removing iodine-131 radionuclide from radioactive liquid waste produced by an Egyptian nuclear power plant using some synthesised alginate derivatives. Two different copolymers, namely sodium alginate poly (acrylic acid) (P₁) and sodium alginate poly (acrylic acid-methacrylic acid) (P₂), are prepared using gamma radiation. The ability of these polymers to remove ¹³¹I radionuclide as sorbents has been investigated. The synthesised polymers exhibit excellent adsorption performance for ¹³¹I ions, and the adsorption equilibrium requires only 30 min, which reveals that the sorption process is kinetically faster than most of the other materials reported previously. The removal percents for ¹³¹I radionuclide at a pH of 3.0 at room temperature on P₁ and P₂ are 77.7% and 84.2%, respectively. The sorption capacities of the two polymers demonstrate that P₂ > P₁, with capacities of 67.9 and 58.5 mg/g, respectively. Four linear kinetic models are investigated: pseudo-first order, pseudo-second order, Elovich, and Weber-Morris models. Regarding their calculated parameters, these models indicate that the adsorption process of I-ions on both P1 and P2 is controlled by chemisorption. Four equilibrium isotherm models (Redlich-Peterson, Langmuir, Freundlich, and Harkin-Jura) are investigated, revealing that the adsorption process is a monolayer and multilayer process on a heterogeneous surface.

In vitro to in vivo acetaminophen hepatotoxicity extrapolation using classical schemes, pharmacodynamic models and a multiscale spatial-temporal liver twin

In vitro to in vivo extrapolation represents a critical challenge in toxicology. In this paper we explore extrapolation strategies for acetaminophen (APAP) based on mechanistic models, comparing classical (CL) homogeneous compartment pharmacodynamic (PD) models and a spatial-temporal (ST), multiscale digital twin model resolving liver microarchitecture at cellular resolution. The models integrate consensus detoxification reactions in each individual hepatocyte. We study the consequences of the two model types on the extrapolation and show in which cases these models perform better than the classical extrapolation strategy that is based either on the maximal drug concentration (Cmax) or the area under the pharmacokinetic curve (AUC) of the drug blood concentration. We find that an CL-model based on a well-mixed blood compartment is sufficient to correctly predict the in vivo toxicity from in vitro data. However, the ST-model that integrates more experimental information requires a change of at least one parameter to obtain the same prediction, indicating that spatial compartmentalization may indeed be an important factor.

Quantitative evaluation of apically extruded debris using TRUShape, TruNatomy, and WaveOne Gold in curved canals

Objective

This study compared the quantity of extruded debris after instrumentation with TRUShape 3D Conforming files, TruNatomy files, and the WaveOne Gold reciprocating system.

Materials and methods

Fifty-one mesiobuccal canals with severe curvatures (25–40°) were assigned to three equal groups according to the rotary system used for preparation, either TRUShape, TruNatomy, or WaveOne Gold files. The extruded debris was collected in pre-weighed glass vials. The data were statistically analyzed using a one-way ANOVA test and Tukey’s post hoc test.

Results

The least extruded debris was obtained with the WaveOne Gold instruments compared to the TRUShape and TruNatomy files (p < 0.001).

Conclusions

Debris extrusion occurs independently of the motion or design of the instrument. The WaveOne Gold system outperformed TRUShape and TruNatomy files in this study.

Comparative histological analysis of the skin for forensic investigation of some animal species

Macroscopical and histological analysis of the skin is fundamental in both human and veterinary forensic investigations. However, databases of differential skin histology of various animal species are rare. The aim of the present study is to identify species-specific differential histological features of the skin that could be used in forensic investigations including animal identification. For this purpose, skin specimens were collected from the neck region of various farm animals including buffalo, cow, camel, sheep, goat, dog, and donkey, and were processed for histological analysis. Our comparative analysis revealed specific histological features in the skin that could differentiate between the studied animal species. The epidermis layer of the skin was very thick in buffalo, intermediate in cow, sheep, goat, dog, and donkey, but very thin in camel. The papillomatous epidermis was very frequent in buffalo, but very rare in cow. In the dermis layer of the skin, four structures were located which showed differential features between the studied animal species: the papillary layer, which was thick in buffalo, camel, sheep, dog, and donkey but thin in cow and goat. The sweat glands, which were few in buffalo, cow, goat, and dog, but numerous and deeply located in the dermis of sheep; they were individually located in all studied animals except in camel and donkey they were arranged in clusters. The hair follicles were characteristic for the skin of sheep as they were present at two different levels in the dermis with simple and compound hair follicles. The sebaceous glands were large and multi-lobular in buffalo, but small and uni-lobular in cow and camel. The hypodermis layer of the skin was very thick in sheep and goat in contrast to all other analyzed animals. In conclusion, the present study provides comprehensive information on the differential histological features of the skin of seven different domestic animal species that could be used as a key in forensic investigations.

Spatial modeling reveals nuclear phosphorylation and subcellular shuttling of YAP upon drug-induced liver injury

The Hippo signaling pathway controls cell proliferation and tissue regeneration via its transcriptional effectors yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). The canonical pathway topology is characterized by sequential phosphorylation of kinases in the cytoplasm that defines the subcellular localization of YAP and TAZ. However, the molecular mechanisms controlling the nuclear/cytoplasmic shuttling dynamics of both factors under physiological and tissue-damaging conditions are poorly understood. By implementing experimental in vitro data, partial differential equation modeling, as well as automated image analysis, we demonstrate that nuclear phosphorylation contributes to differences between YAP and TAZ localization in the nucleus and cytoplasm. Treatment of hepatocyte-derived cells with hepatotoxic acetaminophen (APAP) induces a biphasic protein phosphorylation eventually leading to nuclear protein enrichment of YAP but not TAZ. APAP-dependent regulation of nuclear/cytoplasmic YAP shuttling is not an unspecific cellular response but relies on the sequential induction of reactive oxygen species (ROS), RAC-alpha serine/threonine-protein kinase (AKT, synonym: protein kinase B), as well as elevated nuclear interaction between YAP and AKT. Mouse experiments confirm this sequence of events illustrated by the expression of ROS-, AKT-, and YAP-specific gene signatures upon APAP administration. In summary, our data illustrate the importance of nuclear processes in the regulation of Hippo pathway activity. YAP and TAZ exhibit different shuttling dynamics, which explains distinct cellular responses of both factors under physiological and tissue-damaging conditions.

Inhibition of cytochrome P450 enhances the nephro- and hepatotoxicity of ochratoxin A

The mycotoxin ochratoxin A (OTA) is a contaminant in food that causes nephrotoxicity and to a minor degree hepatotoxicity. Recently, we observed that OTA induces liver damage preferentially to the cytochrome P450 (CYP)-expressing pericentral lobular zone, similar to hepatotoxic substances known to be metabolically toxified by CYP, such as acetaminophen or carbon tetrachloride. To investigate whether CYP influences OTA toxicity, we used a single dose of OTA (7.5 mg/kg; intravenous) with and without pre-treatment with the pan CYP-inhibitor 1-aminobenzotriazole (ABT) 2 h before OTA administration. Blood, urine, as well as liver and kidney tissue samples were collected 24 h after OTA administration for biochemical and histopathological analyses. Inhibition of CYPs by ABT strongly increased the nephro- and hepatotoxicity of OTA. The urinary kidney damage biomarkers kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were increased > 126-fold and > 20-fold, respectively, in mice treated with ABT and OTA compared to those receiving OTA alone. The blood biomarkers of liver damage, alanine transaminase (ALT) and aspartate transaminase (AST) both increased > 21- and 30-fold, respectively, when OTA was administered to ABT pre-treated mice compared to the effect of OTA alone. Histological analysis of the liver revealed a pericentral lobular damage induced by OTA despite CYP-inhibition by ABT. Administration of ABT alone caused no hepato- or nephrotoxicity. Overall, the results presented are compatible with a scenario where CYPs mediate the detoxification of OTA, yet the mechanisms responsible for the pericental liver damage pattern still remain to be elucidated.

Healing Assessment of Osseous Defects after Surgical Removal of Periapical Lesions in the Presence of Hydroxyapatite, Nanohydroxyapatite, and a Combination of Nanohydroxyapatite and Platelet-rich Fibrin: A Clinical Study

Abstract: Aim: to evaluate the bone healing in failed endodontically treated teeth after surgical removal of periapical lesions and placement of hydroxyapatite (HA), nanohydroxyapatite (nHA) and a combination of nanohydroxyapatite with platelet rich fibrin (PRF) periapically. Subjects and methods: the study was conducted on twenty-four patients having periapical radiolucency in single rooted teeth. The selected teeth were divided into three groups: Group A, Group B, and Group C; of 8 teeth each. All the teeth were retreated in two visits. In the first visit the old filling was removed using Protaper retreatment files (Dentsply Sirona®) then irrigation with sodium hypochlorite 2.5% was done. All canals were dried and filled with Di-antibiotic paste (metronidazole and ciprofloxacin). In the second visit the canals were obturated with Pro Taper gutta-percha points and root canal sealer (Adseal resin sealer) followed by surgical intervention in the same day. A periapical curettage along with apicoectomy were established. In all the groups, root end cavity was prepared and filled with MTA (ProRoot MTA; DENTSPLY Tulsa Dental Specialties). In Group A, hydroxyapatite powder was packed in the curetted periapical defect. In Group B, nanohydroxyapatite powder was packed in the curetted periapical defect. In Group C, nanohydroxyapatite with PRF were mixed and packed in the curetted periapical defect. In all groups, patients recall visits were scheduled at 1, 3, and 6 months’ time intervals for clinical and radiological evaluation. Results: after one month; there was a statistically significant difference between the median percentage changes in lesions size in the three groups. Pair-wise comparisons between groups revealed that there was no statistically significant difference between group B (nHA) and group C (PRF and nHA) groups. Both showed statistically significantly higher median percentage reduction in lesions size than group A (HA group). After three as well as six months; there was no statistically significant difference between the median percentage decreases in lesions size in the three groups. Conclusion: It was concluded that nHA combination with PRF produced faster periapical healing (bone regeneration) in the first three months than nHA alone. However, HA produce periapical healing (bone regeneration) after six months.

Interruption of bile acid uptake by hepatocytes after acetaminophen overdose ameliorates hepatotoxicity

BACKGROUND & AIMS

Acetaminophen (APAP) overdose remains a frequent cause of acute liver failure, which is generally accompanied by increased levels of serum bile acids (BAs). However, the pathophysiological role of BAs remains elusive. Herein, we investigated the role of BAs in APAP-induced hepatotoxicity.

METHODS

We performed intravital imaging to investigate BA transport in mice, quantified endogenous BA concentrations in the serum of mice and patients with APAP overdose, analyzed liver tissue and bile by mass spectrometry and MALDI-mass spectrometry imaging, assessed the integrity of the blood-bile barrier and the role of oxidative stress by immunostaining of tight junction proteins and intravital imaging of fluorescent markers, identified the intracellular cytotoxic concentrations of BAs, and performed interventions to block BA uptake from blood into hepatocytes.

RESULTS

Prior to the onset of cell death, APAP overdose causes massive oxidative stress in the pericentral lobular zone, which coincided with a breach of the blood-bile barrier. Consequently, BAs leak from the bile canaliculi into the sinusoidal blood, which is then followed by their uptake into hepatocytes via the basolateral membrane, their secretion into canaliculi and repeated cycling. This, what we termed 'futile cycling' of BAs, led to increased intracellular BA concentrations that were high enough to cause hepatocyte death. Importantly, however, the interruption of BA re-uptake by pharmacological NTCP blockage using Myrcludex B and Oatp knockout strongly reduced APAP-induced hepatotoxicity.

CONCLUSIONS

APAP overdose induces a breach of the blood-bile barrier which leads to futile BA cycling that causes hepatocyte death. Prevention of BA cycling may represent a therapeutic option after APAP intoxication.

LAY SUMMARY

Only one drug, N-acetylcysteine, is approved for the treatment of acetaminophen overdose and it is only effective when given within ∼8 hours after ingestion. We identified a mechanism by which acetaminophen overdose causes an increase in bile acid concentrations (to above toxic thresholds) in hepatocytes. Blocking this mechanism prevented acetaminophen-induced hepatotoxicity in mice and evidence from patients suggests that this therapy may be effective for longer periods after ingestion compared to N-acetylcysteine.

Loss of bile salt export pump aggravates lipopolysaccharide-induced liver injury in mice due to impaired hepatic endotoxin clearance

BACKGROUND AND AIMS

Lipopolysaccharide (LPS) clearance is delayed in cholestatic liver diseases. While compromised clearance by Kupffer cells (KCs) is involved, the role of LPS uptake into hepatocytes and canalicular excretion remains unclear.

APPROACH AND RESULTS

Wild-type (WT) and bile salt export pump (Bsep) knockout (KO) mice were challenged i.p. with LPS. Liver injury was assessed by serum biochemistry, histology, molecular inflammation markers, and immune cell infiltration. LPS concentrations were determined in liver tissue and bile. Subcellular kinetics of fluorescently labeled LPS was visualized by intravital two-photon microscopy, and the findings in Bsep KO mice were compared to common bile duct-ligated (BDL) and multidrug resistance protein 2 (Mdr2) KO mice. Changes in gut microbiota composition were evaluated by 16S ribosomal RNA gene amplicon sequencing analysis. Bsep KO mice developed more pronounced LPS-induced liver injury and inflammatory signaling, with subsequently enhanced production of proinflammatory cytokines and aggravated hepatic immune cell infiltration. After LPS administration, its concentrations were higher in liver but lower in bile of Bsep KO compared to WT mice. Intravital imaging of LPS showed a delayed clearance from sinusoidal blood with a basolateral uptake block into hepatocytes and reduced canalicular secretion. Moreover, LPS uptake into KCs was reduced. Similar findings with respect to hepatic LPS clearance were obtained in BDL and Mdr2 KO mice. Pretreatment with the microtubule inhibitor colchicine inhibited biliary excretion of LPS in WT mice, indicating that LPS clearance is microtubule-dependent. Microbiota analysis showed no change of the gut microbiome between WT and Bsep KO mice at baseline but major changes upon LPS challenge in WT mice.

CONCLUSIONS

Absence of Bsep and cholestasis in general impair LPS clearance by a basolateral uptake block into hepatocytes and consequently less secretion into canaliculi. Impaired LPS removal aggravates hepatic inflammation in cholestasis.

Automated Detection of Portal Fields and Central Veins in Whole-Slide Images of Liver Tissue

Many physiological processes and pathological phenomena in the liver tissue are spatially heterogeneous. At a local scale, biomarkers can be quantified along the axis of the blood flow, from portal fields (PFs) to central veins (CVs), i.e., in zonated form. This requires detecting PFs and CVs. However, manually annotating these structures in multiple whole-slide images is a tedious task. We describe and evaluate a fully automated method, based on a convolutional neural network, for simultaneously detecting PFs and CVs in a single stained section. Trained on scans of hematoxylin and eosin-stained liver tissue, the detector performed well with an F1 score of 0.81 compared to annotation by a human expert. It does, however, not generalize well to previously unseen scans of steatotic liver tissue with an F1 score of 0.59. Automated PF and CV detection eliminates the bottleneck of manual annotation for subsequent automated analyses, as illustrated by two proof-of-concept applications: We computed lobulus sizes based on the detected PF and CV positions, where results agreed with published lobulus sizes. Moreover, we demonstrate the feasibility of zonated quantification of biomarkers detected in different stainings based on lobuli and zones obtained from the detected PF and CV positions. A negative control (hematoxylin and eosin) showed the expected homogeneity, a positive control (glutamine synthetase) was quantified to be strictly pericentral, and a plausible zonation for a heterogeneous F4/80 staining was obtained. Automated detection of PFs and CVs is one building block for automatically quantifying physiologically relevant heterogeneity of liver tissue biomarkers. Perspectively, a more robust and automated assessment of zonation from whole-slide images will be valuable for parameterizing spatially resolved models of liver metabolism and to provide diagnostic information.

Perceptions of Clinical Dental Students Toward Online Education During the COVID-19 Crisis: An Egyptian Multicenter Cross-Sectional Survey

Objectives: To evaluate the perceptions of clinical dental students on the role of online education in providing dental education during the COVID-19 crisis. Materials and Methods: A cross-sectional online survey was sent to four Egyptian dental schools from the 20th of January 2021 to the 3rd of February 2021. Survey questions included the demographics, uses, experiences, perceived benefits, and barriers of distance learning in dentistry during the COVID-19 pandemic. Responses were collected from the clinical dental school students. Categorical data were presented as frequencies (n) and percentages (%) and were analyzed using Fisher's exact test. Results: Three hundred thirty-seven clinical dental students across four Egyptian dental schools responded. Most students used either Google Classroom or Microsoft Teams to access the online content. The data showed that the COVID-19 pandemic affected the academic performance of most participants (97.4%) with varying degrees. On average, students were neutral when asked to rate the online lectures, but did not find online practical education as effective (81.3%) as online theoretical teaching. The commonly described barriers to online teaching included loss of interaction with educators, inappropriateness in gaining clinical skills, and the instability of the internet connection. Conclusion: Despite the reported benefits, clinical dental students in Egypt preferred the hybrid approach in dental education as distance learning represented a prime challenge to gain adequate clinical dental skills.

Regenerative Endodontic Procedures for the Treatment of Necrotic Mature Teeth: A Preliminary Randomised Clinical Trial

AIM

This preliminary randomised, prospective, controlled trial aimed to compare the clinical and radiographic outcomes of two regenerative endodontic procedures (REPs), revitalisation and a platelet-rich fibrin (PRF)-based technique, in the treatment of mature permanent teeth with necrotic pulps.

METHODOLOGY

The trial has been reported according to the Preferred Reporting Items for Randomised Trials in Endodontics 2020 guidelines. The study protocol was registered at the clinical trial registry (ClinicalTrials.gov) with identifier number NCT04158232. Twenty patients with mature necrotic anterior teeth with large periapical lesions were randomly allocated into two groups (n=10): group I, treated with revitalisation with the blood clot (BC) technique, and Group II, treated with a PRF-based technique. The follow-up was for 12 months. Periradicular healing was assessed using standardised radiographs taken at baseline, and at 6 and 12 months after treatment. An electric pulp tester was used to assess whether pulp sensibility had been regained during the follow-up period. Statistical analysis was conducted using Mann-Whitney test and Wilcoxon test for non-parametric data. For parametric data, repeated measures analysis of variance was used. The significance level was set at P≤0.05.

RESULTS

There was a significant increase in periradicular healing in both groups at 6 and 12 months, compared to that at baseline, with no significant difference between the studied groups after 12 months (P=0.143). There was a significant difference between the tooth sensibility readings at baseline, 6-month, and 12-month follow-up timepoints (P<0.001).

CONCLUSIONS

The findings of this preliminary trial indicate the potential for using REPs, such as revitalisation or PRF-based techniques, as treatment options for mature teeth with necrotic pulps. A higher level of evidence obtained through adequately powered clinical trials and longer follow-up periods are required to conclusively validate the different outcomes of REPs.

Influence of optimum torque reverse motion on dentinal cracks after root canal preparation with two nickel-titanium rotary systems

Objectives:

This study was aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Next (PTN) and ProTaper Gold (PTG) using optimum torque reverse (OTR) motion or continuous rotation and dentinal crack formation.

Materials and Methods:

Fifty distobuccal roots of human maxillary first molars were divided into five groups; Group I: PTG Full rotation, Group II: PTG in OTR, Group III: PTN Full rotation, Group IV: PTN in OTR, Group V: unprepared (control group). After mechanical preparation, the distobuccal roots were sectioned horizontally at 3, 6, and 9 mm from the apex. Images were captured using a stereomicroscope at 25X to determine the presence or absence of dentinal cracks. Friedman test was used to compare between root sections followed by Wilcoxon signed-rank test for pairwise comparison. Kruskal–Wallis test was used to compare between tested rotary systems followed by pairwise comparison with Dunn Bonferroni correction (α = 0.05).

Results:

Crack development was significantly higher in PTG using OTR motion 36.7% followed by PTN using OTR 33.3%, while the control group showed no cracks. PTG and PTN with full rotation showed crack development with 23.3% and 13.3%, respectively.

Conclusions:

The type of motion kinematics used during mechanical preparation have an impact on dentinal crack formation. Nickel-titanium instruments with larger taper tend to induce more cracks.

Rimonabant ameliorates hepatic ischemia/reperfusion injury in rats: Involvement of autophagy via modulating ERK- and PI3K/AKT-mTOR pathways

Hepatic ischemia/reperfusion (HIR), which can result in severe liver injury and dysfunction, is usually associated with autophagy and endocannabinoid system derangements. Whether or not the modulation of the autophagic response following HIR injury is involved in the hepatoprotective effect of the cannabinoid receptor 1(CB1R) antagonist rimonabant remains elusive and is the aim of the current study. Rats pre-treated with rimonabant (3 mg/kg) or vehicle underwent 30 min hepatic ischemia followed by 6 hrs. reperfusion. Liver injury was evaluated by serum ALT, AST, bilirubin (total and direct levels) and histopathological examination. The inflammatory, profibrotic and oxidative responses were investigated by assessing hepatic tumor necrosis factor α (TNFα), nuclear factor kappa B (NF-κB), transforming growth factor (TGF-β), lipid peroxidation and reduced glutathione. The hepatic levels of CB1R and autophagic markers p62, Beclin-1, and LC3 as well as the autophagic signaling inhibitors ERK1/2, PI3K, Akt and mTOR were also determined. Rimonabant significantly attenuated HIR-induced increases in hepatic injury, inflammation, profibrotic responses and oxidative stress and improved the associated pathological features. Rimonabant modulated the expression of p62, Beclin-1, and LC3, down-regulated CB1R, and dcreased pERK1/2, PI3K, Akt, and mTOR activities. The current study suggests that rimonabant can protect the liver from IR injury at least in part by inducing autophagy, probably by modulating ERK- and/or PI3K/AKT-mTOR signaling.

Impact of Contracted Endodontic Access Cavity on Shaping Ability of Hyflex Electrical Discharge Machining Single File Using Cone Beam Computed Tomography: An Ex Vivo Study

AIM: The aim of the study was to evaluate and compare the effect of different access cavity designs, using cone-beam computed tomography (CBCT), on root canal transportation, and centralization performed on two rooted maxillary premolars. METHODS: Twenty maxillary premolars were randomly divided into two groups. In Group 1, traditional endodontic cavities (TECs) were prepared. In Group 2, contracted endodontic cavities (CECs) were prepared. Mechanical preparation was done by HyFlex electrical discharge machining (EDM) single file in both groups. CBCT imaging was performed pre- and post-root canal preparation for calculations of root canal transportation and centering ability. RESULTS: Data were analyzed using Mann–Whitney U test and Kruskal–Wallis test. For transportation, teeth with CECs showed the statistically significantly highest median amount of transportation, while as for centering ability, results showed no significant difference between both groups. CONCLUSION: Under the conditions of this study, HyFlex EDM prepared canals with different access cavity designs without significant shaping errors. TEC showed less transportation than CEC, while both TEC and CEC had no effect on the file centering ability.

Spatio-Temporal Multiscale Analysis of Western Diet-Fed Mice Reveals a Translationally Relevant Sequence of Events during NAFLD Progression

Mouse models of non-alcoholic fatty liver disease (NAFLD) are required to define therapeutic targets, but detailed time-resolved studies to establish a sequence of events are lacking. Here, we fed male C57Bl/6N mice a Western or standard diet over 48 weeks. Multiscale time-resolved characterization was performed using RNA-seq, histopathology, immunohistochemistry, intravital imaging, and blood chemistry; the results were compared to human disease. Acetaminophen toxicity and ammonia metabolism were additionally analyzed as functional readouts. We identified a sequence of eight key events: formation of lipid droplets; inflammatory foci; lipogranulomas; zonal reorganization; cell death and replacement proliferation; ductular reaction; fibrogenesis; and hepatocellular cancer. Functional changes included resistance to acetaminophen and altered nitrogen metabolism. The transcriptomic landscape was characterized by two large clusters of monotonously increasing or decreasing genes, and a smaller number of 'rest-and-jump genes' that initially remained unaltered but became differentially expressed only at week 12 or later. Approximately 30% of the genes altered in human NAFLD are also altered in the present mouse model and an increasing overlap with genes altered in human HCC occurred at weeks 30-48. In conclusion, the observed sequence of events recapitulates many features of human disease and offers a basis for the identification of therapeutic targets.

Comparison of Biocompatibility of Experimental Tricalcium Phosphate Cement versus Biodentin and Mineral Trioxide Aggregate used for Furcation Perforation Repair (in vivo study)

Background:

The interaction between the root canal system and the oral cavity caused by iatrogenic perforations significantly affects the treatment outcome and tooth survival.

Objectives:

This study was directed to compare the biocompatibility of an experimental tricalcium phosphate cement versus biodentine and mineral Trioxide aggregate used for furcation perforation repair in dogs.

Methods:

Perforations were done in 60 teeth (premolars and molars) of six adult dogs. Animals were divided randomly into 3 equal groups of 2 animals each according to the post-operative evaluation period of 1 week, 1 month, and 3-months. Each group was further subdivided into 4 subgroups according to either being repaired with the experimental tricalcium phosphate cement (n=6), or Biodentine (n=6), Mineral Trioxide Aggregate (MTA) (n=6), and positive control(n=2). After evaluation periods, tissue blocks were harvested and histologically examined.

Results:

No statistically significant difference was found regarding bone deposition scores and inflammatory reaction in the three groups after 1 week, 1 month, or 3 months. All three groups showed a statistically significant difference between all three time periods. Regardless of the repair material used, inflammation scores at 1-week showed the highest scores, decreasing over time except for the control group.

Conclusion:

The experimental material could be considered as a successful treatment option for repairing furcation perforation.

Gut microbiota depletion exacerbates cholestatic liver injury via loss of FXR signalling

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown aetiology for which there are no approved therapeutic options. Patients with PSC display changes in gut microbiota and in bile acid (BA) composition; however, the contribution of these alterations to disease pathogenesis remains controversial. Here we identify a role for microbiota-dependent changes in BA synthesis that modulates PSC pathophysiology. In a genetic mouse model of PSC, we show that loss of microbiota-mediated negative feedback control of BA synthesis results in increased hepatic BA concentrations, disruption of bile duct barrier function and, consequently, fatal liver injury. We further show that these changes are dependent on decreased BA signalling to the farnesoid X receptor, which modulates the activity of the rate-limiting enzyme in BA synthesis, CYP7A1. Moreover, patients with advanced stages of PSC show suppressed BA synthesis as measured by serum C4 levels, which is associated with poor disease prognosis. Our preclinical data highlight the microbiota-dependent dynamics of BA metabolism in cholestatic liver disease, which could be important for future therapies targeting BA and gut microbiome interactions, and identify C4 as a potential biomarker to functionally stratify patients with PSC and predict disease outcomes.

Modifications to Hepatopancreatobiliary surgical services during COVID-19 partial lockdown in a hospital in northern Malaysia

Maintaining hepatopancreatobiliary (HPB) services during the initial phase of a pandemic in a state referral hospital for COVID-19 presents a few challenges, especially when a nationwide, government-issued partial lockdown is in enforcement. We describe the adaptations to our practice to maintain the services whilst ensuring safety of patients and staff, by postponing non-urgent clinic cases, grouping our staff to two mutually exclusive teams that work on alternate shifts and selecting HPB operative cases according to the modified Risk Urgency Decision Matrix.

Transcriptomic Cross-Species Analysis of Chronic Liver Disease Reveals Consistent Regulation Between Humans and Mice

Mouse models are frequently used to study chronic liver diseases (CLDs). To assess their translational relevance, we quantified the similarity of commonly used mouse models to human CLDs based on transcriptome data. Gene‐expression data from 372 patients were compared with data from acute and chronic mouse models consisting of 227 mice, and additionally to nine published gene sets of chronic mouse models. Genes consistently altered in humans and mice were mapped to liver cell types based on single‐cell RNA‐sequencing data and validated by immunostaining. Considering the top differentially expressed genes, the similarity between humans and mice varied among the mouse models and depended on the period of damage induction. The highest recall (0.4) and precision (0.33) were observed for the model with 12‐months damage induction by CCl₄ and by a Western diet, respectively. Genes consistently up‐regulated between the chronic CCl₄ model and human CLDs were enriched in inflammatory and developmental processes, and mostly mapped to cholangiocytes, macrophages, and endothelial and mesenchymal cells. Down‐regulated genes were enriched in metabolic processes and mapped to hepatocytes. Immunostaining confirmed the regulation of selected genes and their cell type specificity. Genes that were up‐regulated in both acute and chronic models showed higher recall and precision with respect to human CLDs than exclusively acute or chronic genes. Conclusion: Similarly regulated genes in human and mouse CLDs were identified. Despite major interspecies differences, mouse models detected 40% of the genes significantly altered in human CLD. The translational relevance of individual genes can be assessed at https://saezlab.shinyapps.io/liverdiseaseatlas/.

Comparison of Apically Extruded Debris Associated with Different Irrigation Techniques after Removal of Intracanal Medicaments

 This study aimed to compare the effect of XP-endo Finisher file (XPF), passive ultrasonic irrigation (PUI) and conventional irrigation technique using side-vented needle (SVN) on the amount of apically extruded debris after the removal of calcium hydroxide Ca(OH)2 and double antibiotic paste (DAP). Materials and Methods: Sixty extracted human mandibular premolars were used. After decronation, all canals were prepared up to the ProTaper Next X4 file (Dentsply Maillefer, Ballaigues, Switzerland). After dryness, teeth were randomly assigned into 2 groups (n=30) according to the Type of intracanal medication used; Ca(OH)2 and DAP then incubated at 37 °C and 100% humidity. After one week, Samples in each group were randomly assigned to 3 subgroups (n=10) according to the method used for medicament removal: XPF, PUI and SVN. Debris extruded during the removal procedure were collected into pre-weighed Eppendorf tubes then left to dry in an incubator at 37°C for 15 days.  The amount of extruded debris was assessed with an analytical balance and calculated by subtracting the initial weight from the final weight of the tube.  Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U test. Results:  there was no statistically significant difference regarding the amount of apically extruded debris after using the three irrigation techniques in removal of both Ca(OH)2 and DAP (P-value = 0.141, Effect size = 0.160) and (P-value = 0.237, Effect size = 0.073) respectively. Conclusions:  Neither XPF nor PUI increase the risk of intracanal medicament extrusion beyond the apex.

Subcellular spatio-temporal intravital kinetics of aflatoxin B1 and ochratoxin A in liver and kidney

Local accumulation of xenobiotics in human and animal tissues may cause adverse effects. Large differences in their concentrations may exist between individual cell types, often due to the expression of specific uptake and export carriers. Here we established a two-photon microscopy-based technique for spatio-temporal detection of the distribution of mycotoxins in intact kidneys and livers of anesthetized mice with subcellular resolution. The mycotoxins ochratoxin A (OTA, 10 mg/kg b.w.) and aflatoxin B1 (AFB1, 1.5 mg/kg b.w.), which both show blue auto-fluorescence, were analyzed after intravenous bolus injections. Within seconds after administration, OTA was filtered by glomeruli, and enriched in distal tubular epithelial cells (dTEC). A striking feature of AFB1 toxicokinetics was its very rapid uptake from sinusoidal blood into hepatocytes (t1/2 ~ 4 min) and excretion into bile canaliculi. Interestingly, AFB1 was enriched in the nuclei of hepatocytes with zonal differences in clearance. In the cytoplasm of pericentral hepatocytes, the half-life (t1/2~ 63 min) was much longer compared to periportal hepatocytes of the same lobules (t1/2 ~ 9 min). In addition, nuclear AFB1 from periportal hepatocytes cleared faster compared to the pericentral region. These local differences in AFB1 clearance may be due to the pericentral expression of cytochrome P450 enzymes that activate AFB1 to protein- and DNA-binding metabolites. In conclusion, the present study shows that large spatio-temporal concentration differences exist within the same tissues and its analysis may provide valuable additional information to conventional toxicokinetic studies.

POS1276 LONG TERM OUTCOME OF MULTIPLE ULTRASOUND GUIDED SUPRASCAPULAR NERVE BLOCK IN TREATMENT OF FROZEN SHOULDER IN DIABETIC PATIENTS

Background:

Frozen shoulder is prevalent among diabetic patients, and usually has aggressive course, with more tendency to be bilateral and resistant to treatment. Suprascapular nerve block (SSNB) is used with increasing frequency by anesthetists and rheumatologists in the management of frozen shoulder. We previously introduced a protocol of nine injections for SSNB with better short term outcome than single SSNB injection (1). Long term outcome of SSNB in management of frozen shoulder is still not detected.

Objectives:

To evaluate the long term effect of multiple (nine) ultrasound guided supra-scapular nerve block in treatment of diabetic frozen shoulder.

Methods:

A retrospective cohort study followed up 40 diabetic patients who received a course of ultrasound guided multiple supra-scapular nerve block (9 injections) on 2014. In this study we retrospectively assessed the patients from previously recorded data at a mean duration of 6 years after completing the 9 injection course SSNB clinically by measuring the shoulder active range of motion (using a goniometer in three planes: abduction, internal, and external rotation). Visual analogue scale and Functional assessment by shoulder pain and disability index (SPADI).

Results:

Thirty four patients (85% of original cohort) completed the long term follow up.

The patients were 19 (55.9%) females, 60.6 y mean age, and the mean of disease duration was 85.6 months. The majority of patients (33 patients 97.05%) continues improvement and gained within normal complete range of motions in all directions and excellent grades of shoulder function (Table 1).

Table 1.Clinical ParametersAt base lineAt 4 monthsLast follow up at (72months±4)**P valueSPADI pain score (100)(68.8 ± 0.5)a(10.3 ± 7.4)b(0.9±1.9)c0.00*SPADI disability score (100)(69.2 ± 7.7)a(6.25 ± 2.25)b(0.4±0.8)c0.00*SPADI total (100)(69.1 ± 8.5)a(8.15 ± 5.4)b(1.1±0.9)c0.00*Patient global assessment (100)(90.2 ± 8.2)a(8.2 ± 4.2)b(0.4±2.1)c0.00*Night pain (100)(55.4±10.2)a(10.3 ± 4.9)b(2.3±1.1)c0.00*Abduction (180°)(77.5 ± 4.7)a(170.3 ± 10.3)b(174.2±6.2)b0.00*External rotation (100 °)(46 ± 12.6)a(80.1 ± 10.2)b(86.4±10.3)b0.00*Internal rotation (70 °)(34.5 ± 2.4)a(55.4 ± 10.1)b(60.2±9.5)b0.00*

* P <0.05 there was a statistical significant difference

•A,b,c--- the alphabet of different symbols ---means a significant statistical difference between groups

SPADI: shoulder pain and disability index

Conclusion:

The multiple injection courses for supra-scapular nerve block has an excellent long term efficacy as treatment of diabetic frozen shoulder. This method should be the treatment of choice in patients of diabetic frozen shoulder who do not respond to physiotherapy.

References:

[1]Mortada, M. A., Ezzeldin, N., Abbas, S. F., Ammar, H. A. & Salama, N. A. Multiple versus single ultrasound guided suprascapular nerve block in treatment of frozen shoulder in diabetic patients. J. Back Musculoskelet. Rehabil. 30, 537–542 (2017).

Disclosure of Interests:

None declared

Emergency Laparotomy in a COVID-19 patient with acute abdomen

We describe here the first laparotomy involving a COVID-19 patient in Malaysia. A 60-year-old man screened positive for SARS-CoV-2 in March 2020 and developed acute abdomen in the ward in Hospital Sultanah Bahiyah, Kedah. He underwent laparotomy and cholecystectomy for gangrenous cholecystitis. All personnel adhered to infectious control precautions, donning full personal protective equipment (PPE) throughout the surgery. Post-operatively, due to raised septic parameters, he was carefully diagnosed with and treated empirically for superimposed bacterial sepsis instead of cytokine release syndrome, with confirmed blood culture of Klebsiella pneumoniae. Patient was discharged well later. None of the staff involved in his care developed COVID-19 infection.

Clinical implications of conventional cytogenetics, fluorescence in situ hybridization (FISH) and molecular testing in chronic myeloid leukaemia patients in the tyrosine kinase inhibitor era - A review

Chronic myeloid leukaemia (CML) provides an illustrative disease model for both molecular pathogenesis of cancer and rational drug therapy. Imatinib mesylate (IM), a BCR-ABL1 targeted tyrosine kinase inhibitor (TKI) drug, is the first line gold standard drug for CML treatment. Conventional cytogenetic analysis (CCA) can identify the standard and variant Philadelphia (Ph) chromosome, and any additional complex chromosome abnormalities at diagnosis as well as during treatment course. Fluorescence in situ hybridization (FISH) is especially important for cells of CML patients with inadequate or inferior quality metaphases or those with variant Ph translocations. CCA in conjunction with FISH can serve as powerful tools in all phases of CML including the diagnosis, prognosis, risk stratification and monitoring of cytogenetic responses to treatment. Molecular techniques such as reverse transcriptase-polymerase chain reaction (RT-PCR) is used for the detection of BCR-ABL1 transcripts at diagnosis whereas quantitative reverse transcriptase-polymerase chain reaction (qRTPCR) is used at the time of diagnosis as well as during TKI therapy for the quantitation of BCR-ABL1 transcripts to evaluate the molecular response and minimal residual disease (MRD). Despite the excellent treatment results obtained after the introduction of TKI drugs, especially Imatinib mesylate (IM), resistance to TKIs develops in approximately 35% - 40% of CML patients on TKI therapy. Since point mutations in BCR-ABL1 are a common cause of IM resistance, mutation analysis is important in IM resistant patients. Mutations are reliably detected by nested PCR amplification of the translocated ABL1 kinase domain followed by direct sequencing of the entire amplified kinase domain. The objective of this review is to highlight the importance of regular and timely CCA, FISH analysis and molecular testing in the diagnosis, prognosis, assessment of therapeutic efficacy, evaluation of MRD and in the detection of BCR-ABL1 kinase mutations which cause therapeutic resistance in adult CML patients.

AB0177 RHEUMATOID ARTHRITIS SAUDI DATABASE (RASD): A SINGLE CENTER EXPERIENCE

Background:

National Registries are essential to direct current practice and design appropriate management strategies1. Rheumatoid arthritis (RA) registries in the middle east and north Africa remain scarcely represented2.

Objectives:

Our objective is to describe the Saudi RA population and to compare the findings to internationally reported data.

Methods:

This is a cross sectional, analytical study that was conducted at Doctor Soliman Fakeeh Hospital (DSFH). The study ran from December of 2014 and concluded in December of 2018 using a pool of 433 patients. Inclusion criteria included adults older than 18 years of age who fulfilled the 2010 American College of Rheumatology criteria for diagnosis of RA3. Data were collected from patients and entered in a specially designed program for this registry. They included main demographic details,, lag times to final disease diagnosis. Disease Activity Score-28-C Reactive Protein (DAS-28-CRP) was calculated on presentation and on subsequent visits with intervals ranging from three to six months between them. Multiple regression model was used to assess the predictors of disease activity. We charted the lines of medications given, including conventional and biologic disease modifying antirheumatic drugs (DMARDs), following treat to target strategies4.

Results:

Out of 430 patients, 76.68% were female, while only 23.32% were male and the mean age was found to be 49.26 years with SD±11.

At initial presentation, 45.5% had demonstrated active disease (moderate or high disease activity) based on DAS-28-CRP scores while 54.5% were in remission or low disease activity. Out of the total number of clinic visitors, 330 had regular follow ups for more than 1 year while 103 patients were either irregularly visiting the rheumatology clinic or had lost follow up. The remission rates after 1 year had increased to 79.7% (263 patients), while 9.7% (32 patients) had low disease activity and no patients had sustained high disease activity at the end of follow up. It was also found that the female gender, higher Health Assessment Questionnaire-Disability Index (HAQ-DI) and a longer lag1/lag2 period were associated with higher disease activity in our population. Biologic medications had been used by 129 patients (29.7%) while conventional DMARDs were given to 304 patients (70.3%).

Conclusion:

We described a population of RA patients in a single center in SA. We detected higher remission rates at one year of follow up. This could be attributed to many factors, including good referral systems and treat to target strategies with easier access to biologic medications.

References:

[1]Singh JA, Saag KG, Bridges SL Jr, Akl EA, Bannuru RR, Sullivan MC, Vaysbrot E, McNaughton C, Osani M, Shmerling RH, Curtis JR, Furst DE, Parks D, Kavanaugh A, O’Dell J, King C, Leong A, Matteson EL, Schousboe JT, Drevlow B, Ginsberg S, Grober J, St Clair EW, Tindall E, Miller AS, McAlindon T. 2015 American College of Rheumatology Guideline for the Treatment of Rheumatoid Arthritis.Arthritis Rheumatol.2016 Jan;68(1):1-26.

[2]Smolen, Josef S., et al. “EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2013 update.”Annals of the rheumatic diseases73.3 (2014): 492-509.

[3]Saag KG, Teng GG, Patkar NM, Anuntiyo J, Finney C, Curtis JR, et al. American College of Rheumatology 2008 recommendations for the use of nonbiologic and biologic disease-modifying antirheumatic drugs in rheumatoid arthritis.Arthritis Rheum2008;59: 762–84.

[4]Hussain W, Noorwali A, Janoudi N. From symptoms to diagnosis: an observational study of the journey of rheumatoid arthritis patients in Saudi Arabia.Oman Med J.2016;31(1):29.

Disclosure of Interests:

Rola Hassan Grant/research support from: Pfizer pharmaceuticals, Mohamed Cheikh Grant/research support from: Pfizer pharmaceuticals, Hani Almoallim Grant/research support from: Pfizer pharmaceuticals, Hanan Faruqui Grant/research support from: Pfizer pharmaceuticals, Reem AlQuraa Grant/research support from: Pfizer pharmaceuticals, Ayman Eissa Grant/research support from: Pfizer pharmaceuticals, Aous Alhazmi Grant/research support from: Pfizer pharmaceuticals, Nahid Janoudi Grant/research support from: Pfizer pharmaceuticals

Is Procalcitonin more superior to hs-CRP in the diagnosis of infection in diabetic foot ulcer?

INTRODUCTION

Procalcitonin (PCT) has recently emerged as a marker for diagnosing infection. This study aimed to compare the performance of PCT and other infection markers in diagnosing infected diabetic foot ulcer (IDFU).

MATERIALS AND METHODS

A total of 128 diabetic patients with foot ulcers were recruited and divided into two groups, consisting of 73 patients in the IDFU group and 55 in the non-infected diabetic foot ulcer (NIDFU). The severity of infection in IDFU patients was graded based on the Infectious Disease Society of America-International Working Group on the Diabetic Foot classification. Blood samples from all the patients were collected for measurement of PCT, high sensitivity C-reactive protein (hs-CRP) and white cell count (WBC). The area under the receiver operating curves (AUC) were then constructed and analysed.

RESULTS

PCT, hs-CRP and WBC levels were significantly higher in the IDFU group compared to NIDFU with hs-CRP demonstrated the highest AUC (0.91; p <0.001) followed by PCT (0.814; p < 0.001) and lastly WBC (0.775; p < 0.001). The best cut off value, sensitivity and specificity for the presence of infection in diabetic foot, were 3.47 mg/dL, 80% and 89% for hs-CRP, 0.11 ng/ml, 70% and 87% for PCT and 11.8x109/L, 60% and 90% for WBC. All the infection markers showed significant positive correlations with infection severity of DFU.

CONCLUSION

This study showed that hs-CRP is a more sensitive marker for diagnosing IDFU. Although PCT is useful in differentiating IDFU from NIDFU, the use of PCT is not necessary as it adds little value to the current practice.