Intrapulmonary pharmacokinetics of high doses of tigecycline in patients with ventilator-associated pneumonia.

Tigecycline is commonly used for infections by multidrug-resistant bacteria. However, it is not approved for ventilator-associated pneumonia (VAP) as increased mortality has been reported in VAP patients treated with conventional doses. The purpose of this study was to prospectively evaluate the intrapulmonary pharmacokinetics of off-label high-dose tigecycline in patients with VAP. Nine mechanically ventilated patients received tigecycline intravenously (loading dose 200 mg followed by 100 mg every 12 h). After ≥5 doses, two bronchoscopies were performed in each patient on consecutive days and eight blood samples were collected. Tigecycline concentrations in plasma and bronchoalveolar lavage fluid were determined by liquid chromatography. The urea dilution method was used to calculate epithelial lining fluid (ELF) concentrations. A two-compartmental pharmacokinetic (PK) model with linear elimination was used to estimate PK parameters. Mean patient age was 69 ± 11.86 years and mean APACHE II score was 21. The estimated population mean PK parameters (relative standard error) were: clearance, 11.64 L/h (54%); volume of distribution in central compartment, 79.01 L (37%); volume of distribution in peripheral compartment, 92.95 L (17%); intercompartmental clearance, 62.81 L/h (34%); and ELF penetration ratio, 2.41 (40%). Cmax, Cmin, plasma AUC0-12, plasma fAUC0-12 and ELF AUC0-12 were 1.99 ± 1.82 µg/mL, 0.81 ± 1.27 µg/mL, 12.89 ± 17.25 µg•h/mL, 3.24 ± 3.09 µg•h/mL and 7.13 ± 2.61 µg•h/mL, respectively. The increased plasma and ELF AUC0-12 achieved with a 200 mg daily tigecycline dose, combined with high ELF penetration, support the effectiveness of off-label high-dose tigecycline in VAP.

AP39 ameliorates high fat diet-induced liver injury in young rats via alleviation of oxidative stress and mitochondrial impairment.

Non-alcoholic fatty liver disease (NAFLD) is a complication of childhood obesity and an oxidative stress-related multisystem disease. A mitochondria-targeting hydrogen sulfide (H2S) donor AP39 has antioxidant property, while the mechanism underlying the function of AP39 on pediatric NAFLD remains undefined. Here, 3-week-old SD rats were received a high-fat diet (HFD) feeding and injected with AP39 (0.05 or 0.1 mg/kg/day) via the tail vein for up to 7 weeks. AP39 reduced weight gain of HFD rats and improved HFD-caused liver injury, as evidenced by reduced liver index, improved liver pathological damage, decreased NAFLD activity score, as well as low alanine transaminase (ALT) and aspartate transaminase (AST) activities. AP39 also reduced serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C) concentrations but increased high-density lipoprotein-cholesterol (HDL-C). Moreover, AP39 prevented reactive oxygen species (ROS) generation, reduced MDA content and increased glutathione (GSH) level and superoxide dismutase (SOD) activity. Furthermore, AP39 increased H2S level, protected mitochondrial DNA (mtDNA), reduced mitochondrial swelling, and restored mitochondrial membrane potential (MMP) alteration. Notably, AP39 diminished HIF-1α mRNA and protein level, possibly indicating the alleviation in mitochondrial damage. In short, AP39 protects against HFD-induced liver injury in young rats probably through attenuating lipid accumulation, oxidative stress and mitochondrial dysfunction.

Actualización en COVID-19 y enfermedad hepática / COVID-19 and liver disease: An update

La pandemia producida por SARS-CoV-2 ha supuesto uno de los mayores desafíos del sistema sanitario español. El impacto del virus sobre el hígado no es bien conocido, pero en pacientes con enfermedades hepáticas crónicas, especialmente en estadios avanzados, puede comprometer de forma crítica la supervivencia y desencadenar descompensaciones. El tratamiento en esta subpoblación es complejo por la potencial hepatotoxicidad de algunos fármacos empleados. Más allá, la pandemia también ha impactado negativamente sobre aquellos con enfermedades hepáticas que no han adquirido la enfermedad, ya que la redistribución de los recursos humanos y materiales hacia la atención de pacientes con COVID-19 ha provocado una merma en su tratamiento, diagnóstico y seguimiento que, a buen seguro, tendrá consecuencias negativas en el futuro. La reorganización eficiente de las unidades de Hepatología es una necesidad de primer orden para aminorar el impacto de la pandemia sobre una población tan vulnerable como los pacientes con hepatopatía

The SARS-CoV-2 pandemic has proven to be a serious challenge for the Spanish healthcare system. The impact of the virus on the liver is not well known, but in patients with chronic liver disease, mostly in advanced stages, it can critically compromise survival and trigger decompensation. Treatment in this subpopulation is complex due to the potential hepatotoxicity of some of the medicinal products used. Moreover, the pandemic has also negatively impacted patients with liver disease who have not contracted COVID-19, since the reallocation of human and material resources to the care of patients with the virus has resulted in a decrease in the treatment, diagnosis and follow-up of patients with liver disease, which will surely have negative consequences in the near future. Efficient reorganization of hepatology units is a priority to minimise the impact of the pandemic on a population as vulnerable as liver disease patients

Distinguishing between Hepatic Inflammation and Fibrosis with MR Elastography.

Purpose To investigate the utility of magnetic resonance (MR) elastography-derived mechanical properties in the discrimination of hepatic inflammation and fibrosis in the early stages of chronic liver diseases. Materials and Methods All studies were approved by the institutional animal care and use committee. A total of 187 animals were studied, including 182 mice and five pigs. These animals represented five different liver diseases with a varying combination and extent of hepatic inflammation, fibrosis, congestion, and portal hypertension. Multifrequency three-dimensional MR elastography was performed, and shear stiffness, storage modulus, shear loss modulus, and damping ratio were calculated for all animals. Necroinflammation, fibrosis, and portal pressure were either histologically scored or biochemically and physically quantified in all animals. Two-sided Welch t tests were used to evaluate mean differences between disease and control groups. Spearman correlation analyses were used to evaluate the relationships between mechanical parameters and quantitative fibrosis extent (hydroxyproline concentration) and portal pressure. Results Liver stiffness and storage modulus increased with progressively developed fibrosis and portal hypertension (mean stiffness at 80 Hz and 48-week feeding, 0.51 kPa ± 0.12 in the steatohepatitis group vs 0.29 kPa ± 0.01 in the control group; P = .02). Damping ratio and shear loss modulus can be used to distinguish inflammation from fibrosis at early stages of disease, even before the development of histologically detectable necroinflammation and fibrosis (mean damping ratio at 80 Hz and 20-week feeding, 0.044 ± 0.012 in the steatohepatitis group vs 0.014 ± 0.008 in the control group; P < .001). Damping ratio and liver stiffness vary differently with respect to cause of portal hypertension (ie, congestion- or cirrhosis-induced hypertension). These differentiation abilities have frequency-dependent variations. Conclusion Liver stiffness and damping ratio measurements can extend hepatic MR elastography to potentially enable assessment of necroinflammatory, congestive, and fibrotic processes of chronic liver diseases. © RSNA, 2017 Online supplemental material is available for this article.

Hepatoprotective Effect of Low Doses of Caffeine on CCl4-Induced Liver Damage in Rats.

Several studies have shown the hepatoprotective effect of the consumption of coffee and tea, which is mainly attributed to caffeine. Many experimental studies have demonstrated this effect; however, these studies used high caffeine doses that are not related to human consumption. The aim of this study was to evaluate the hepatoprotective effect of low doses of caffeine on carbon tetrachloride (CCl4)-treated rats. Low doses of caffeine (CAFF) 5 and 10 mg/kg (CAFF5 and CAFF10) were evaluated in chronic liver damage induced by CCl4 (0.75 mL/kg) in rats. CAFF treatment was administered once a day and CCl4 administration was twice weekly for 10 weeks. Liver function tests (biochemical markers) and functional (sleeping time) and histological (hematoxylin-eosin and Masson trichrome stains) parameters were carried out at the end of damage treatment. Daily treatments of CAFF5 and CAFF10 exhibited a hepatoprotective effect supported by a decrease of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (AP) serum activities and bilirubin serum levels compared with control and also restored serum albumin levels and liver glutathione (GSH). Moreover, CAFF prevented CCl4-induced prolongation in pentobarbital sleeping time and a decrease of liver fibrosis and cell death. Our results demonstrated that low doses of CAFF exert a hepatoprotective effect against CCl4 -induced liver damage in rats.

Kupffer cell-mediated exacerbation of methimazole-induced acute liver injury in rats.

Methimazole (MTZ), an anti-thyroid drug, is known to cause liver injury in humans. It has been demonstrated that MTZ-induced liver injury in Balb/c mice is accompanied by T helper (Th) 2 cytokine-mediated immune responses; however, there is little evidence for immune responses associated with MTZ-induced liver injury in rats. To investigate species differences in MTZ-induced liver injury, we administered MTZ with a glutathione biosynthesis inhibitor, L-buthionine-S,R-sulfoximine (BSO), to F344 rats and subsequently observed an increase in plasma alanine aminotransferase (ALT) and high-mobility group box 1 (HMGB1), which are associated with hepatic lesions. The hepatic mRNA expression of innate immune-related genes significantly increased in BSO- and MTZ-treated rats, but the change in Th2-related genes was not much greater than the change observed in the previous mouse study. Moreover, an increase in Kupffer cells and an induction of the phosphorylation of extracellular signal-regulated kinase (ERK)/c-Jun N-terminal kinase (JNK) proteins were accompanied by an increase in Toll-like receptor 4 (TLR4) expression, indicating that Kupffer cell activation occurs through HMGB1-TLR4 signaling. To elucidate the mechanism of liver injury in rats, gadolinium chloride, which inactivates the function of Kupffer cells, was administered before BSO and MTZ administration. The gadolinium chloride treatment significantly suppressed the increased ALT, which was accompanied by decreased hepatic mRNA expression related to innate immune responses and ERK/JNK phosphorylation. In conclusion, Kupffer cell-mediated immune responses are crucial factors for the exacerbation of MTZ-induced liver injury in rats, indicating apparent species differences in the immune-mediated exacerbation of liver injury between mice and rats.

Prevention of liver fibrosis by intrasplenic injection of high-density cultured bone marrow cells in a rat chronic liver injury model.

Endothelial progenitor cells (EPCs) from bone marrow have proven to be functional for the prevention of liver fibrosis in chronic liver injury. However, expansion of EPCs in culture is complicated and expansive. Previously, we have established a simple method that could enrich and expand EPCs by simple seeding bone marrow cells in high density dots. The purpose of this study is to evaluate whether cells derived from high-density (HD) culture of rat bone marrow cells could prevent the liver fibrosis in a chronic liver injury rat model, induced by carbon tetrachloride (CCl4). Flow cytometric analysis showed that cells from HD culture were enriched for EPCs, expressing high levels of EPC markers. Intrasplenic injection of HD cultured bone marrow cells in the CCl4-induced liver injury rat showed an enhanced antifibrogenic effect compared with animals treated with cells from regular-density culture. The antifibrogenic effect was demonstrated by biochemical and histological analysis 4 weeks post-transplantation. Furthermore, cells from HD culture likely worked through increasing neovascularization, stimulating liver cell proliferation, and suppressing pro-fibrogenic factor expression. HD culture, which is a simple and cost-effective procedure, could potentially be used to expand bone marrow cells for the treatment of liver fibrosis.

Evidence against a stem cell origin of new hepatocytes in a common mouse model of chronic liver injury.

Hepatocytes provide most liver functions, but they can also proliferate and regenerate the liver after injury. However, under some liver injury conditions, particularly chronic liver injury where hepatocyte proliferation is impaired, liver stem cells (LSCs) are thought to replenish lost hepatocytes. Conflicting results have been reported about the identity of LSCs and their contribution to liver regeneration. To address this uncertainty, we followed candidate LSC populations by genetic fate tracing in adult mice with chronic liver injury due to a choline-deficient, ethionine-supplemented diet. In contrast to previous studies, we failed to detect hepatocytes derived from biliary epithelial cells or mesenchymal liver cells beyond a negligible frequency. In fact, we failed to detect hepatocytes that were not derived from pre-existing hepatocytes. In conclusion, our findings argue against LSCs, or other nonhepatocyte cell types, providing a backup system for hepatocyte regeneration in this common mouse model of chronic liver injury.

Glycyrrhizinate reduces portal hypertension in isolated perfused rat livers with chronic hepatitis.

AIM: To investigate the effects of diammonium glycyrrhizinate (Gly) on portal hypertension (PHT) in isolated portal perfused rat liver (IPPRL) with carbon tetrachloride (CCl4)-induced chronic hepatitis. METHODS: PHT model was replicated with CCl4 in rats for 84 d. Model was identified by measuring the ascetic amounts, hepatic function, portal pressure in vivo, splenic index, and pathological alterations. Inducible nitric oxide synthase (iNOS) in liver was assessed by immunohistochemistry. IPPRLs were performed at d0, d28, d56, and d84. After phenylephrine-induced constriction, Gly was geometrically used to reduce PHT. Gly action was expressed as median effective concentration (EC50) and area under the curve (AUC). Underlying mechanism was exploited by linear correlation between AUC values of Gly and existed iNOS in portal triads. RESULTS: PHT model was confirmed with ascites, splenomegaly, serum biomarkers of hepatic injury, and elevated portal pressure. Pathological findings had shown normal hepatic structure at d0, degenerations at d28, fibrosis at d56, cirrhosis at d84 in PHT rats. Pseudo lobule ratios decreased and collagen ratios increased progressively along with PHT development. Gly does dose-dependently reduce PHT in IPPRLs with CCl4-induced chronic hepatitis. Gly potencies were increased gradually along with PHT development, characterized with its EC50 at 2.80 × 10⁻¹°, 3.03 × 10⁻¹¹, 3.77 × 10⁻¹¹ and 4.65×10⁻¹¹ mol/L at d0, d28, d56 and d84, respectively. Existed iNOS was located at hepatocyte at d0, stellate cells at d28, stellate cells and macrophages at d56, and macrophages in portal triads at d84. Macrophages infiltrated more into portal triads and expressed more iNOS along with PHT development. AUC values of Gly were positively correlated with existed iNOS levels in portal triads. CONCLUSION: Gly reduces indirectly PHT in IPPRL with CCl4-induced chronic hepatitis. The underlying mechanisms may relate to rescue NO bioavailability from macrophage-derived peroxynitrite in portal triads.

Severe toxic hepatitis associated with dronedarone.

Dronedarone was introduced in 2009 as a new antiarrhythmic agent and since then has been increasingly prescribed in atrial fibrillation or flutter. To date, two cases of severe toxic hepatitis have been reported in patients treated with dronedarone, both requiring emergency liver transplantation, and the FDA as well as the EMA have issued warnings about possible severe hepatotoxicity of dronedarone. Here we report an additional case of toxic hepatitis associated with dronedarone presenting with acute liver failure, followed by spontaneous recovery, in a 69-year old woman.

Green tea extract supplementation ameliorates CCl4-induced hepatic oxidative stress, fibrosis, and acute-phase protein expression in rat.

BACKGROUND/PURPOSE: We evaluated the long-term effects of green tea extract (GTE) supplementation on oxidative stress, biliary acute phase protein expression, and liver function in CCl(4)-induced chronic liver injury. METHODS: We evaluated the antioxidant activity of GTE in comparison with those of vitamin C, vitamin E, and ß-carotene in vitro by using an ultrasensitive chemiluminescence analyzer. Chronic liver injury was induced by intraperitoneally administering carbon tetrachloride (CCl(4)) (1 mL/kg body weight, twice weekly) to female Wistar rats for 8 weeks. The effects of low (4 mg/kg body weight per day) and high (20 mg/kg body weight per day) doses of intragastric GTE on CCl(4)-induced liver dysfunction and fibrosis were examined by measuring the bile and blood reactive oxygen species levels and biochemical parameters by using Western blot and two-dimensional polyacrylamide gel electrophoresis techniques. RESULTS: GTE has greater scavenging activity against O(2)(-), H(2)O(2), and Hypochlorous acid (HOCl) in vitro than vitamin C, vitamin E, and ß-carotene do. In vivo, CCl(4) markedly increased bile and blood reactive oxygen species production, lipid accumulation, number of infiltrated leukocytes, fibrosis, hepatic hydroxyproline content, and plasma alanine aminotransferase and aspartate aminotransferase activities, and reduced plasma albumin levels. Two-dimensional polyacrylamide gel electrophoresis revealed that CCl(4) increased the acute-phase expression of six biliary proteins and decreased hepatic B-cell lymphoma 2 (Bcl-2), catalase, and CuZn superoxide dismutase protein expression. GTE supplementation attenuated CCl(4)-enhanced oxidative stress, levels of biochemical parameters, pathology, and acute-phase protein secretion, and preserved antioxidant/antiapoptotic protein expression. CONCLUSION: GTE supplementation attenuates CCl(4)-induced hepatic oxidative stress, fibrosis, acute phase protein excretion, and hepatic dysfunction via the antioxidant and antiapoptotic defense mechanisms.

The hepatoprotective effect of coumarin and coumarin derivates on carbon tetrachloride-induced hepatic injury by antioxidative activities in rats

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Coumarins are a vast group of natural compounds and some of them possess antioxidant activities. The comparison of the antioxidant activity of some coumarins with various chemical molecular structure has not been investigated in previous studies. Therefore, this study was aimed to investigate the hepatoprotective effect against carbon tetrachloride (CCl4) -induced hepatic injury by coumarin (1,2-benzopyrone) and coumarin derivatives, esculetin (6,7-dihydroxycoumarin), scoparone (6,7-dimethoxycoumarin), and 4-methylumbelliferone (7-hyroxy-4-methyl) in male Sprague–Dawley rats. Product of lipid peroxidation, malondialdehyde (MDA), activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) were evaluated for oxidative stress in hepatic injury. Gamma glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH) were detected in plasma as a biomarker of hepatic injury. Significantly elevated levels of MDA and lowered levels of SOD and CAT activities were observed in liver of rats exposed to CCl4, when compared to control values. Similarly, administration of CCl4 increased LDH and GGT levels in serum. Pre-treatment of rats with esculetin (35 mg kg−1, orally) and scoparone (35 mg kg−1, orally) significantly prevented CCl4-induced decrease in MDA levels and increase in SOD and CAT, whereas 4-methylumbelliferone (35 mg kg−1) and coumarin (30 mg kg−1) had no effect against CCl4-induced rise in serum enzymes. Esculetin and scoparone also showed protective properties as was evidenced in reduced LDH and GGT levels in serum. The results of this study indicate that the chemical structures of coumarins play an important role in the prevention of oxidative stress (AU)

Characteristics of idiosyncratic drug-induced liver injury in children: results from the DILIN prospective study.

BACKGROUND: The spectrum and severity of idiosyncratic drug-induced liver injury (DILI) in children are not well established. PATIENTS AND METHODS: The DILIN (Drug-Induced Liver Injury Network) Prospective Study is a longitudinal multicenter study designed to determine the etiologies, risk factors, and outcomes of suspected DILI. Between September 2004 and September 2009, 30 children ages 2 to 18 years with suspected DILI who met eligibility criteria were enrolled and studied for at least 6 months. RESULTS: Mean age was 14 years; 70% were girls. Antimicrobial (50%) and central nervous system agents (40%) were the most commonly implicated drug classes, with minocycline (4), isoniazid (3), azithromycin (3), atomoxetine (3), and lamotrigine (3) the leading agents. Median time from drug initiation to symptom onset was 32 days. Peak (median) liver chemistries were aspartate aminotransferase 503  U/L, alanine aminotransferase 727  U/L, alkaline phosphatase 331  U/L, and total bilirubin 3.9  mg/dL. Autoantibodies were common (64%). Liver injury pattern was hepatocellular 78%, cholestatic 13%, and mixed 9%. The DILI episode was scored: mild 32%, moderate 44%, severe 20%, and fatal (within 6 months) 4%. Causality assessment was definite 36%, very likely 36%, probable 16%, possible 8%, and unlikely 4%. Seven percent had persistent liver test abnormalities at 6-month follow-up suggesting chronic DILI. Liver biopsies from 12 children most frequently demonstrated chronic hepatitis or bile duct injury. CONCLUSIONS: Idiosyncratic DILI in children is most commonly caused by antimicrobial or central nervous system agents and usually presents with a hepatocellular injury pattern. The majority of patients recover, but morbidity and infrequent mortality are seen.

Isolevuglandins covalently modify phosphatidylethanolamines in vivo: detection and quantitative analysis of hydroxylactam adducts.

Levuglandins (LGs) and isolevuglandins (isoLGs, also called "isoketals" or "isoKs") are extraordinarily reactive products of cyclooxygenase- and free radical-induced oxidation of arachidonates. We now report the detection in vivo and quantitative analysis of LG/isoLG adducts that incorporate the amino group of phosphatidylethanolamines (PEs) into LG/isoLG-hydroxylactams. Notably, LC-MS/MS detection of these hydroxylactams is achieved with samples that are an order of magnitude smaller and sample processing is much simpler and less time consuming than required for measuring protein-derived LG/isoLG-lysyl lactams. A key feature of our protocol is treatment of biological phospholipid extracts with phospholipase A(2) to generate mainly 1-palmitoyl-2-lysoPE-hydroxylactams from heterogeneous mixtures of phospholipids with a variety of acyl groups on the 2 position. Over 160% higher mean levels of LG/isoLG-PE-hydroxylactam (P<0.001) were detected in liver from chronic ethanol-fed mice (32.4+/-6.3 ng/g, n=6) compared to controls (12.1+/-1.5 ng/g, n=4), and mean levels in plasma from patients with age-related macular degeneration (5.2+/-0.4 ng/ml, n=15) were elevated approximately 53% (P<0.0001) compared to those of healthy volunteers (3.4+/-0.1 ng/ml, n=15). Just as LG/isoLG-protein adducts provide a dosimeter of oxidative injury, this study suggests that LG/isoLG-PE-hydroxylactams are potential biomarkers for assessing risk for oxidative stress-stimulated diseases.

A critical role of STAT1 in streptozotocin-induced diabetic liver injury in mice: controlled by ATF3.

It is well-established that the administration of streptozotocin accelerates diabetic liver injury as well as type-I diabetes, however the underlying mechanisms are poorly understood. Here we investigated the molecular mechanisms of diabetic liver injury in a model of streptozotocin (STZ)-induced type-I diabetes. STZ administration induced type-1 diabetes and chronic liver injury was associated with increased STAT1, which is implicated in diabetic liver injury by virtue of its ability to promote hepatocyte apoptosis, in the liver and pancreas, which were all strongly inhibited in STAT1(-)(/-) mice. Similarly, STZ-induced ATF3, a stress-inducible gene, was completely abolished in the liver of IFN-gamma(-/-) mice, but not in STAT1(-/-) mice. Inhibition of STAT1 by siRNA or dominant-negative DNA did not affect ATF3 protein expression but blocked IFN-gamma-induced ATF3 translocation from the cytosol into the nucleus. In contrast, inhibition of ATF3 by using siRNA diminished STAT1 protein expression and IFN-gamma/STZ-induced hepatocyte apoptosis. Furthermore, GST pull-down and co-IP assay showed that STAT1 bound to C-terminal domain of ATF3. Such direct interaction increased the stability of STAT1 by inhibiting its ubiquitination as well as proteasome activity. Our results suggest that STAT1 is a common signaling pathway contributing to STZ-induced diabetes and diabetic liver injury. ATF3 functions as a potent regulator of STAT1 stability, accelerating STZ-induced diabetes and diabetic liver injury.

Long-term minocycline use for acne in healthy adolescents can cause severe autoimmune hepatitis.

Over the years, a variety of abnormal immune reactions to minocycline have been reported including arthritis, systemic lupus erythematosus, and hepatitis. The current report describes the detailed clinical and pathologic features of 3 patients who presented with chronic/autoimmune hepatitis alone while on minocycline at our hospital over a 2-year period. Minocycline use in these patients was temporally related to onset of severe hepatitis. Adolescents with such a reaction to minocycline have been included in previous reports but have not been well described as a distinct entity. We have compared our cases with similar cases previously reported with a review of the literature and a discussion of the implications for prescribing physicians.

Comparative hepatic toxicity: prechronic/chronic liver toxicity in rodents.

The morphologic assessment of the gross and microscopic appearance of the liver can provide a broad base of knowledge concerning the potential toxicity of a drug or chemical. This information may either lead to an understanding of the underlying mechanism of toxicity or guide further study to discern the mode of action of the hepatotoxicity. In standard regulatory bioassays, toxicity studies are conducted during phase 1 and phase 2 of the development process to define the acute, subchronic and chronic toxicity of the test compound. In the liver, there are a limited number of morphologic changes that can be identified using conventional light microscopy. These morphologic alterations are often characterized as "adaptive," consisting of an exaggerated normal physiologic response; "pharmacologic," consisting of an expected alteration in response to the desired action of the test article; or "adverse," consisting of morphologic alterations that are generally undesired, progressive and deleterious to the normal function of the cell(s) involved. Morphologic evidence of adverse effects may involve hepatocytes, the biliary system, hepatic vasculature, Kupffer cells, or stellate cells (Ito cells). In drug discovery and development programs, it is necessary to utilize a multidisciplinary approach, using different endpoints, to investigate the same or similar biological responses in the liver. This results in large amounts of data that must be organized in a retrievable fashion. In order for such a multidisciplinary approach to succeed, each discipline must organize and generate their data in a manner that is easily used by others in the process. The toxicologic pathologist must develop and use standardized nomenclature and diagnostic criteria when examining the liver so that data from various investigators can be compared in a useful manner.

Fatal reactivation of hepatitis B virus following cytotoxic chemotherapy for acute myelogenous leukemia: fibrosing cholestatic hepatitis.

Hepatitis B virus (HBV) is a well known pathogen that sometimes causes fulminant hepatitis in patients undergoing cytotoxic chemotherapy. Fibrosing cholestatic hepatitis (FCH) is a recently recognized unique variant of viral hepatitis, which has been occasionally reported in HBV-infected recipients of liver, renal, or bone marrow transplantation. We present here a 48-yr-old male in whom HBV was reactivated during post-remission chemotherapy for acute myelogenous leukemia, which resulted in rapidly fatal outcome. He manifested with deterioration of liver function in association with enormous replication of HBV. Liver biopsy showed marked ballooning of hepatocytes, cholestasis, and periportal fibrosis with minimum infiltrates. Immunostaining revealed that hepatocytes were strongly positive for hepatitis B surface antigen. Under the diagnosis of FCH, he was treated with lamivudine and interferon beta, which was not effective. Autopsy showed severe atrophy of the liver and marked degeneration of hepatocytes. Hematologists should be aware that FCH is a fatal complication that can develop under post-chemotherapy immunosuppressed conditions. Although there is no convincing evidence, prophylactic administration of lamivudine seems to be a reasonable strategy.

Nitrofurantoin-induced chronic active hepatitis.

BACKGROUND: Nitrofurantoin is a commonly prescribed urinary antiseptic. Hepatic injury has been associated with its use. OBJECTIVES: To present three patients in whom long-term exposure to the drug resulted in chronic active hepatitis; and to review the epidemiology, clinical immunology, histopathology, pathogenetic features and treatment of previously reported cases. RESULTS: Withdrawing nitrofurantoin once the diagnosis was suspected did not lead to remission of the liver disease and glucocorticoids had to be administered. One patient died of liver failure. CONCLUSIONS: Awareness of this unusual side effect of nitrofurantoin is important and caution should be taken before prescribing it. Over the past years new insight into the immune nature of this drug has emerged.

The influence of interferon alpha on the rat liver injured by chronic administration of carbon tetrachloride.

Due to their complex and not fully known etiopathogenesis as well as difficulties in treatment, chronic hepatitis and cirrhosis still remain one of the main problems of hepatologists. Nowadays, the use of IFN alpha is considered the most effective method of treatment in chronic hepatitis. Recently, a new property of IFN, i.e. its effects on the reduction of fibrosis, has been discovered. The aim of the paper was to examine the effects of IFN alpha on biochemical parameters (AlAt and AspAt activities), on the metabolic function of the liver and its morphologic picture observed under the light and electron microscope after the 3- and 6-week CCl4-induced damage. The experiments were carried out in Wistar male rats. To evaluate the liver function, the test of aminophenazone elimination in the isolated perfused rat livers was used according to Miller modified by Hafte. Additionally, AspAt and AlAt activities were determined. The liver specimens were analysed under the light and electron microscope and using immunohistochemical methods. The findings show that after the 3-week CCl4-induced liver damage, IFN alpha does not significantly affect AlAt and AspAt activities, irrespective of the dose used. IFN alpha administered after the 6-week damage significantly changes those activities when the doses used are high. It was found that carbon tetrachloride does not result in evident cirrhotic changes, however it activates Ito cells, causes focal retraction of the stroma and fibrosis. The increased number of Ito cells in Disse's space observed in immunohistochemical and ultrastructural examinations is indicative of the activation of liver fibrotic processes following CCl4 administration in both variants used. IFN alpha substantially weakens fibrogenesis of the CCl4-damaged liver which is visible in the decreased number of Ito cells and weaker expression of the stroma retraction. Moreover, IFN alpha administered to the experimental animals after the CCl4-induced injury of the liver increases aminophenazone clearance, especially when used in higher doses. Positive effects of IFN confirmed in the studies suggest that the drug may be used in patients with chronic hepatitis and early cirrhosis since it is likely not only to eliminate the virus but also to improve the liver function and reduce fibrosis.