Search

Background: Dyslipidemia increases cardiovascular disease risk, the leading cause of death worldwide. Under time-restricted feeding (TRF), wherein food intake is restricted to a consistent window of <12 hours, weight gain, glucose intolerance, inflammation, dyslipidemia, and hypercholesterolemia are all reduced in mice fed an obesogenic diet. LDLR (low-density lipoprotein receptor) mutations are a major cause of familial hypercholesterolemia and early-onset cardiovascular disease., Methods: We subjected benchmark preclinical models, mice lacking LDLR-knockout or ApoE knockout to ad libitum feeding of an isocaloric atherogenic diet either ad libitum or 9 hours TRF for up to 13 weeks and assessed disease development, mechanism, and global changes in hepatic gene expression and plasma lipids. In a regression model, a subset of LDLR-knockout mice were ad libitum fed and then subject to TRF., Results: TRF could significantly attenuate weight gain, hypercholesterolemia, and atherosclerosis in mice lacking the LDLR-knockout mice under experimental conditions of both prevention and regression. In LDLR-knockout mice, increased hepatic expression of genes mediating β-oxidation during fasting is associated with reduced VLDL (very-low-density lipoprotein) secretion and lipid accumulation. Additionally, increased sterol catabolism coupled with fecal loss of cholesterol and bile acids contributes to the atheroprotective effect of TRF. Finally, TRF alone or combined with a cholesterol-free diet can reduce atherosclerosis in LDLR-knockout mice. However, mice lacking ApoE, which is an important protein for hepatic lipoprotein reuptake do not respond to TRF., Conclusions: In a preclinical animal model, TRF is effective in both the prevention and regression of atherosclerosis in LDLR knockout mice. The results suggest TRF alone or in combination with a low-cholesterol diet can be a lifestyle intervention for reducing cardiovascular disease risk in humans., Competing Interests: S. Panda is the author of the book “The Circadian Code and The Circadian Diabetes Code” and serves on the scientific advisory board of Hooke London. J.L. Witztum received consulting fees from Ionis Pharmaceuticals Inc; royalties/patent beneficiary from the University of California San Diego; and ownership interest from Kleanthi, and Oxitope.

Allylpyrocatechol (APC) was isolated from betel leaf and its possible role in L-thyroxin (L-T 4 )-induced thyrotoxic rats was evaluated. The disease condition, thyrotoxicosis was confirmed by higher levels of thyroid hormones and low thyrotropin (TSH) in serum. Increased hepatic activities of 5'-mono-deiodinase(5'D1), glucose-6-phospatase (G-6-Pase); serum concentrations of alanine transaminase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase(LDH) and tumour necrosis factor-alpha(TNF-α) were observed in thyrotoxic rats. Hepatic lipid peroxidation(LPO) was also increased and the endogenous antioxidants were depleted in these rats. In western blot analysis thyroid peroxidase expression was found to be reduced, whereas thyrotropin receptor(TSHR) expression was enhanced in thyroid gland of these animals. On the other hand, APC treatment in thyrotoxic rats decreased the levels of serum thyroid hormones, ALT, AST, TNF-α and LDH, as well as hepatic 5' D1 and G-6-Pase activities. However, it increased the serum TSH levels. APC also reduced the hepatic LPO and increased the cellular antioxidants in thyrotoxic rats. However, expression of TSHR was inhibited and TPO was increased by APC. The test compound also improved histological features in both liver and thyroid. Present report appears to be the first one that indicates the positive role of APC in ameliorating T 4 -induced thyrotoxicosis.

NOD2 is essential for antimicrobial innate immunity and tissue homeostasis, but require tight regulation to avert pathology. A focal point of NOD2 signaling is RIP2, which upon polyubiquitination nucleates the NOD2:RIP2 complex, enabling signaling events leading to inflammation, yet the precise nature and the regulation of the polyubiquitins coordinating this process remain unclear. Here we show that NOD2 signaling involves conjugation of RIP2 with lysine 63 (K63), K48 and M1 polyubiquitin chains, as well as with non-canonical K27 chains. In addition, we identify MYSM1 as a proximal deubiquitinase that attenuates NOD2:RIP2 complex assembly by selectively removing the K63, K27 and M1 chains, but sparing the K48 chains. Consequently, MYSM1 deficient mice have unrestrained NOD2-mediated peritonitis, systemic inflammation and liver injury. This study provides a complete overview of the polyubiquitins in NOD2:RIP2 signaling and reveal MYSM1 as a central negative regulator restricting these polyubiquitins to prevent excessive inflammation.

The mechanisms by which feeding and fasting drive rhythmic gene expression for physiological adaptation to daily rhythm in nutrient availability are not well understood. Here we show that, upon feeding, the RNA-binding protein NONO accumulates within speckle-like structures in liver cell nuclei. Combining RNA-immunoprecipitation and sequencing (RIP-seq), we find that an increased number of RNAs are bound by NONO after feeding. We further show that NONO binds and regulates the rhythmicity of genes involved in nutrient metabolism post-transcriptionally. Finally, we show that disrupted rhythmicity of NONO target genes has profound metabolic impact. Indeed, NONO-deficient mice exhibit impaired glucose tolerance and lower hepatic glycogen and lipids. Accordingly, these mice shift from glucose storage to fat oxidation, and therefore remain lean throughout adulthood. In conclusion, our study demonstrates that NONO post-transcriptionally coordinates circadian mRNA expression of metabolic genes with the feeding/fasting cycle, thereby playing a critical role in energy homeostasis., (Copyright © 2017 Elsevier Inc. All rights reserved.)

PRIP-Interacting protein with methyl transferase domain (PIMT) serves as a molecular bridge between CREB-binding protein (CBP)/ E1A binding protein p300 (Ep300) -anchored histone acetyl transferase and the Mediator complex sub-unit1 (Med1) and modulates nuclear receptor transcription. Here, we report that ERK2 phosphorylates PIMT at Ser(298) and enhances its ability to activate PEPCK promoter. We observed that PIMT is recruited to PEPCK promoter and adenoviral-mediated over-expression of PIMT in rat primary hepatocytes up-regulated expression of gluconeogenic genes including PEPCK. Reporter experiments with phosphomimetic PIMT mutant (PIMT(S298D)) suggested that conformational change may play an important role in PIMT-dependent PEPCK promoter activity. Overexpression of PIMT and Med1 together augmented hepatic glucose output in an additive manner. Importantly, expression of gluconeogenic genes and hepatic glucose output were suppressed in isolated liver specific PIMT knockout mouse hepatocytes. Furthermore, consistent with reporter experiments, PIMT(S298D) but not PIMT(S298A) augmented hepatic glucose output via up-regulating the expression of gluconeogenic genes. Pharmacological blockade of MAPK/ERK pathway using U0126, abolished PIMT/Med1-dependent gluconeogenic program leading to reduced hepatic glucose output. Further, systemic administration of T4 hormone to rats activated ERK1/2 resulting in enhanced PIMT ser(298) phosphorylation. Phosphorylation of PIMT led to its increased binding to the PEPCK promoter, increased PEPCK expression and induction of gluconeogenesis in liver. Thus, ERK2-mediated phosphorylation of PIMT at Ser(298) is essential in hepatic gluconeogenesis, demonstrating an important role of PIMT in the pathogenesis of hyperglycemia.

Background and Aim: Liver fibrosis is an established determinant of prognosis and therapy in chronic hepatitis B (CHB). The role of fibroscan in assessing fibrosis in CHB remains unclear. Present study was designed to correlate fibroscan with liver biopsy and determine whether fibroscan can avoid liver biopsy in patients with CHB., Methods: Fibroscan and liver biopsy were performed in 382 consecutive patients with CHB. Biopsies were reviewed by pathologist blinded to the fibroscan value. Discriminant values of liver stiffness measurement (LSM) to reasonably exclude and predict significant fibrosis were calculated from receiver operating characteristic (ROC) curves. The factors affecting LSM independent of fibrosis were assessed., Results: Three hundred fifty-seven patients were included (mean age 30.1 ± 9.7 years, male : female 17 : 3). There was significant correlation between LSM and histological fibrosis (r = 0.58, P < 0.001). The area under ROC curve of LSM for significant fibrosis (F0-1 vs. F2-4), bridging fibrosis (F0-2 vs. F3-4), and cirrhosis (F0-3 vs. F4) was 0.84 (95% CI: 0.78-0.89), 0.94 (95% CI: 0.89-0.99), and 0.93 (95% CI: 0.85-1.00), respectively. LSM < 6.0 KPa could exclude significant (F ≥ 2) and bridging fibrosis (F ≥ 3) with a negative predictive value (NPV) of 92.4% and 99.5%, respectively. Cut-off of 9 KPa could detect significant (F ≥ 2) and bridging fibrosis (F ≥ 3) with specificity of 95% and 97%, respectively, and had a positive predictive value (PPV) of 84.3% in predicting significant fibrosis. LSM < 6 KPa and > 9 KPa matched with histological fibrosis in 227/250 (91%) patients. Therefore, fibroscan could avoid liver biopsy in 70% (250/357) patients with an accuracy > 90%. Histological fibrosis, ALT > 5 times, and age > 40 years were independent determinants of increased liver stiffness., Conclusions: Fibroscan accurately assessed fibrosis and could avoid liver biopsy in more than two-thirds of patients with CHB., (© 2013 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.)

In the mouse liver, circadian transcriptional rhythms are necessary for metabolic homeostasis. Whether dynamic epigenomic modifications are associated with transcript oscillations has not been systematically investigated. We found that several antisense RNA, lincRNA, and microRNA transcripts also showed circadian oscillations in adult mouse livers. Robust transcript oscillations often correlated with rhythmic histone modifications in promoters, gene bodies, or enhancers, although promoter DNA methylation levels were relatively stable. Such integrative analyses identified oscillating expression of an antisense transcript (asPer2) to the gene encoding the circadian oscillator component Per2. Robust transcript oscillations often accompanied rhythms in multiple histone modifications and recruitment of multiple chromatin-associated clock components. Coupling of cycling histone modifications with nearby oscillating transcripts thus established a temporal relationship between enhancers, genes, and transcripts on a genome-wide scale in a mammalian liver. The results offer a framework for understanding the dynamics of metabolism, circadian clock, and chromatin modifications involved in metabolic homeostasis., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Hepatitis E virus (HEV) is an emerging pathogen and the most common cause of acute viral hepatitis all over the world. We describe here an immunohistochemical method for the detection of HEV antigens (pORF2 and pORF3) in formalin-fixed, paraffin-embedded liver tissues using monoclonal antibodies raised against two of the virus proteins (pORF2 and pORF3). We analysed their specificity and sensitivity in comparison with serology and nucleic acid detection in cases of acute liver failure (ALF). We used this test on 30 liver biopsies collected post-mortem from the patients of ALF caused by HEV infection. These cases were selected on the basis of positive results for enzyme immunoassay (IgM anti-HEV). Of the 30 cases taken from the archives of the Department of Pathology, the antibodies successfully stained all. However, only 25 serum samples (83.3%) of these were positive for HEV RNA. Fifteen controls used (Five noninfected liver tissues, five HBV- and five hepatitis C virus-infected liver tissues) were all negative. The immunohistochemical assay described here may prove a valuable tool for the detection of HEV infection in biopsy, autopsy and explant liver tissues and can serve as a link along with other available tests to delineate the extent of HEV-associated problem worldwide., (© 2011 Blackwell Publishing Ltd.)

Hepatitis E virus infection (HEV) is a major cause of acute viral hepatitis in the developing world. The immunopathology of HEV infections has not yet been elucidated. The virus is noncytopathic, and therefore, liver injury may be attributed to immune-mediated damage by cytotoxic T cells and natural killer cells. Therefore, we studied the nature of immune cells involved in HEV-induced liver damage using immunohistochemistry in liver biopsies taken from patients with HEV-induced acute liver failure and demonstrated a significant infiltration of activated CD8(+) T cells containing granzymes. These findings suggest the possible involvement of cytotoxic T cells in disease pathogenesis during HEV infection., (© 2010 Blackwell Publishing Ltd.)

In mammals, the circadian oscillator generates approximately 24-h rhythms in feeding behavior, even under constant environmental conditions. Livers of mice held under constant darkness exhibit circadian rhythm in abundance in up to 15% of expressed transcripts. Therefore, oscillations in hepatic transcripts could be driven by rhythmic food intake or sustained by the hepatic circadian oscillator, or a combination of both. To address this question, we used distinct feeding and fasting paradigms on wild-type (WT) and circadian clock-deficient mice. We monitored temporal patterns of feeding and hepatic transcription. Both food availability and the temporal pattern of feeding determined the repertoire, phase, and amplitude of the circadian transcriptome in WT liver. In the absence of feeding, only a small subset of transcripts continued to express circadian patterns. Conversely, temporally restricted feeding restored rhythmic transcription of hundreds of genes in oscillator-deficient mouse liver. Our findings show that both temporal pattern of food intake and the circadian clock drive rhythmic transcription, thereby highlighting temporal regulation of hepatic transcription as an emergent property of the circadian system.

Circadian clocks coordinate behavioral and physiological processes with daily light-dark cycles by driving rhythmic transcription of thousands of genes. Whereas the master clock in the brain is set by light, pacemakers in peripheral organs, such as the liver, are reset by food availability, although the setting, or "entrainment," mechanisms remain mysterious. Studying mouse fibroblasts, we demonstrated that the nutrient-responsive adenosine monophosphate-activated protein kinase (AMPK) phosphorylates and destabilizes the clock component cryptochrome 1 (CRY1). In mouse livers, AMPK activity and nuclear localization were rhythmic and inversely correlated with CRY1 nuclear protein abundance. Stimulation of AMPK destabilized cryptochromes and altered circadian rhythms, and mice in which the AMPK pathway was genetically disrupted showed alterations in peripheral clocks. Thus, phosphorylation by AMPK enables cryptochrome to transduce nutrient signals to circadian clocks in mammalian peripheral organs.

The circadian clock is a molecular and cellular oscillator found in most mammalian tissues that regulates rhythmic physiology and behavior. Numerous investigations have addressed the contribution of circadian rhythmicity to cellular, organ, and organismal physiology. We recently developed a method to look at transcriptional oscillations with unprecedented precision and accuracy using high-density time sampling. Here, we report a comparison of oscillating transcription from mouse liver, NIH3T3, and U2OS cells. Several surprising observations resulted from this study, including a 100-fold difference in the number of cycling transcripts in autonomous cellular models of the oscillator versus tissues harvested from intact mice. Strikingly, we found two clusters of genes that cycle at the second and third harmonic of circadian rhythmicity in liver, but not cultured cells. Validation experiments show that 12-hour oscillatory transcripts occur in several other peripheral tissues as well including heart, kidney, and lungs. These harmonics are lost ex vivo, as well as under restricted feeding conditions. Taken in sum, these studies illustrate the importance of time sampling with respect to multiple testing, suggest caution in use of autonomous cellular models to study clock output, and demonstrate the existence of harmonics of circadian gene expression in the mouse., Competing Interests: The authors have declared that no competing interests exist.

Aims: This study was performed to evaluate the therapeutic efficacy of nanocapsulated flavonoidal quercetin (QC) in combating arsenic-induced reactive oxygen species (ROS)-mediated oxidative damage in hepatocytes and brain cells in a rat model., Main Methods: Hepatic and neuronal cell damage in rats was made by a single injection (sc) of sodium arsenite (NaAsO(2), 13 mg/kg b. wt. in 0.5 ml of physiological saline). A single dose of 500 microl of quercetin suspension (QC) (QC 8.98 micromol/kg) or 500 microl of nanocapsulated QC (NPQC) (QC 8.98 micromol/kg) was given orally to rats at 90 min prior to the arsenite injection., Key Findings: Inorganic arsenic depositions (182+/-15.6 and 110+/-12.8 ng/g protein) were found in hepatic and neuronal mitochondrial membranes. Antioxidant levels in hepatic and neuronal cells were reduced significantly by arsenic. NPQC prevented the arsenite-induced reduction in antioxidant levels in the liver and brain. Arsenic induced a substantial decrease in liver and brain cell membrane microviscosities, and NPQC treatment resulted in a unique protection against the loss. A significant correlation between mitochondrial arsenic and its conjugated diene level was observed both in liver and brain cells for all experimental rats., Significance: Arsenic-specific antidotes are used against arsenic-induced toxicity. However, the target site is poorly recognized and therefore achieving an active concentration of drug molecules can be a challenge. Thus, our objective was to formulate NPQC and to investigate its therapeutic potential in an oral route against arsenite-induced hepatic and neuronal cell damage in a rat model.

1. The efficacy of coumarin (1,2-benzopyrone) was examined for the regulation of hyperthyroidism in female rats. 2. Coumarin was administered (10 mg/kg per day for 15 days) to l-thyroxine (L-T(4))-induced hyperthyroid as well as to euthyroid rats and changes in serum concentrations of thyroid hormones and in associated parameters, such as serum cholesterol, activity of hepatic 5'-monodeiodinase (5'DI) and glucose-6-phosphatase (G-6-Pase), glycogen content, bodyweight and daily food consumption, were analysed. Simultaneously, changes in hepatic lipid peroxidation (LPO), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were also investigated. 3. Although L-T(4) administration increased serum levels of thyroid hormones, the activity of hepatic 5'DI, G-6-Pase and LPO and daily food consumption, it decreased the level of serum cholesterol, hepatic glycogen content and the activities of anti-oxidant enzymes, such as SOD, CAT and GSH. 4. However, simultaneous administration of coumarin for 15 days to a group of hyperthyroid animals reversed most of the aforementioned changes, indicating its potential to ameliorate hyperthyroidism. Moreover, the drug did not increase, but rather decreased, hepatic LPO, suggesting its safe nature. 5. The present findings reveal a positive role for coumarin in the regulation of hyperthyroidism without any hepatotoxicity. It also appears that the test compound inhibits thyroid function at both a glandular level and at the level of peripheral conversion of T(4) to tri-iodothyronine.

The ethanolic extract from the fruits of Emblica officinalis Gaertn (Euphorbiaceae) was investigated to evaluate its possible ameliorating effects, on the L-thyroxine (L-T4) induced hyperthyroidism and on hepatic lipid peroxidation in mice. While an increase in serum T3 (triiodothyronine) and T4 (thyroxine) concentrations, and in a thyroid dependent parameter, hepatic glucose 6-phospatase (glu-6-pase) activity was observed in L-T4 (0.5 mg/kg/d) treated animals, simultaneous oral administration of the plant extract at a dose of 250 mg/kg/d (p.o.) for 30 days in hyperthyroid mice reduced T3 and T4 concentrations by 64 and 70% respectively as compared to a standard antithyroid drug, propyl thiouracil (PTU) that decreased the levels of the thyroid hormones by 59 and 40% respectively. The plant extract also maintained nearly normal value of glu-6-pase activity in hyperthyroid mice. The plant extract also decreased hepatic lipid peroxidation (LPO) and increased the superoxide dismutase (SOD) and catalase (CAT) activities in hyperthyroid mice, exhibiting its hepatoprotective nature. Our findings suggest that the test material may potentially ameliorate the hyperthyroidism with an additional hepatoprotective benefit.

Piperine, the main alkaloid of Piper nigrum fruits, was evaluated for its thyroid hormone and glucose regulatory efficacy in adult male Swiss albino mice. Its daily oral administration (2.50 mg/kg) for 15 days lowered the serum levels of both the thyroid hormones, thyroxin (T (4)) and triiodothyronine (T (3)) as well as glucose concentrations with a concomitant decrease in hepatic 5'D enzyme and glucose-6-phospatase (G-6-Pase) activity. However, no significant alterations were observed in animals treated with 0.25 mg/kg of piperine in any of the activities studied except an inhibition in serum T (3) concentration. The decrease in T (4), T (3) concentrations and in G-6-Pase were comparable to that of a standard antithyroid drug, Proylthiouracil (PTU). The hepatic lipid-peroxidation (LPO) and the activity of endogenous antioxidants, superoxide dismutase (SOD), and catalase (CAT) were not significantly altered in either of the doses. It appears that the action of P. nigrum on thyroid functions is mediated through its active alkaloid, piperine. We also suggest that a higher dose of piperine may inhibit thyroid function and serum glucose concentration in euthyroid individuals.

Circadian oscillators orchestrate daily rhythms in behaviour and physiology to adapt to the predictable daily appearance of light. Identifying the complement of circadian-regulated transcripts in major organs is critical in the understanding of both the biochemical targets of clock regulation and the mechanism of such control. Recent analysis of temporal gene expression patterns in peripheral and central oscillators have revealed hundreds of circadian-regulated transcripts, most of which are tissue-specific. Mapping of these transcripts to physiological processes and pathways has revealed that major functions of those organs tested are under circadian regulation, and importantly, key and rate-limiting steps in these processes are often the targets of circadian control. Overall, nearly 100% of the mammalian genome may be regulated by the clock, demonstrating the pervasive control of the circadian oscillator in temporal coordination of transcription throughout the organism. This wealth of circadian outputs offers exciting challenges to deciphering systems-level transcriptional regulatory mechanisms that underlie spatiotemporal gene expression.

The effects of daily administration of Withania somnifera root extract (1.4 g/kg body wt.) and Bauhinia purpurea bark extract (2.5 mg/kg body wt.) for 20 days on thyroid function in female mice were investigated. While serum triiodothyronine (T3) and thyroxine (T4) concentrations were increased significantly by Bauhinia, Withania could enhance only serum T4 concentration. Both the plant extracts showed an increase in hepatic glucose-6-phosphatase (G-6-Pase) activity and antiperoxidative effects as indicated either by a decrease in hepatic lipid peroxidation (LPO) and/or by an increase in the activity of antioxidant enzyme(s). It appears that these plant extracts are capable of stimulating thyroid function in female mice.

The importance of ashwagandha root extract in the regulation of thyroid function with special reference to type-I iodothyronine 5'-monodeiodinase activity in mice liver has been investigated. Although the root extract (1.4 g kg(-1)) administered daily for 20 days by gastric intubation increased serum 3,3',5-triiodothyronine (T3) and tetraiodothyronine (T4) concentrations and hepatic glucose-6-phosphatase activity, hepatic iodothyronine 5'-monodeiodinase activity did not change significantly. Furthermore, ashwagandha root extract significantly reduced hepatic lipid peroxidation, whereas the activity of antioxidant enzymes such as superoxide dismutase and catalase were increased. These findings reveal that the ashwagandha root extract stimulates thyroidal activity and also enhances the antiperoxidation of hepatic tissue.

The effects of Ocimum sanctum leaf extract on the changes in the concentrations of serum triiodothyronine (T3), thyroxine (T4) and serum cholesterol; in the activities of hepatic glucose-6-phosphatase (G-6-P), superoxide dismutase (SOD) and catalase (CAT); hepatic lipid peroxidation (LPO) and on the changes in the weight of the sex organs were investigated. While the plant extract at the dose of 0.5 g kg-1 body wt. for 15 days significantly decreased serum T4 concentrations, hepatic LPO and G-6-P activity, the activities of endogenous antioxidant enzymes, SOD and CAT were increased by the drug. However, no marked changes were observed in serum T3 level, T3/T4 ratio and in the concentration of serum cholesterol. It appears that Ocimum sanctum leaf extract is antithyroidic as well as antioxidative in nature.

Hepatitis E virus (HEV), the causative agent of enteric non-A, non-B hepatitis, is a positive-stranded RNA virus. Because of the virus's inability to grow in culture, several nonhuman primates have been used for the propagation of HEV. Using strand-specific reverse transcription-polymerase chain reaction (RT-PCR), we demonstrate the presence of negative-stranded HEV RNA replicative intermediates in the livers of infected animals. This constitutes the first direct evidence of HEV replication in the liver of the infected animals and reinforces the validity of such a model to study HEV infection, disease pathogenesis, and immunity.

Attachment of hepatitis B virus to a hepatoblastoma cell line (HepG2) was examined using a synthetic peptide corresponding to the pre-S1 (21-47) region of the envelope protein. Scatchard analysis revealed a single class binding site of Kd 104 +/- 27 nM/l and 5.4 +/- 1.2 x 10(5) sites per cell. Competition of HBV with pre-S1 peptides was dose dependent, and demonstrated it as the dominant binding site. In view of the suggested sequence homology between the peptide and IgA, cross-competition studies were carried out. The results indicate no direct role of IgA receptor in HBV binding. The receptor for the pre-S1 peptide was identified as a single major peptide of molecular weight 31 kD using in-situ ligand receptor crosslinking.

Lack of information regarding the presence of native albumin polymer in serum and its structural similarity to the one produced by glutaraldehyde treatment casts doubt on the postulate that hepatitis B virus attachment to hepatocytes is mediated through polymerized albumin. We used a sandwich enzyme-linked immunosorbent assay with murine monoclonal antibodies raised against glutaraldehyde-polymerized albumin to detect native albumin polymer in human serum and its cross-reactivity with other albumin polymers. Presence of polymerized albumin receptor on the HepG2 cell was studied by radioreceptor assay. Purified hepatitis B virus and synthetic peptide analogous to part of pre-S2 sequence (120-145) were used to study polymerized albumin-dependent attachment of the virus to HepG2 cells. Antibodies raised against pre-S2 peptide were used to inhibit the pre-S2 and hepatitis B virus attachment to HepG2 cells. Glutaraldehyde-treated polymerized albumin was found to be immunologically cross-reactive with native albumin polymer. Its levels were found to be significantly raised in sera of patients with liver diseases. Polymerized albumin has specific saturable receptor on HepG2 cells with two classes of binding sites of different equilibrium dissociation constant (Kd1 = (16 +/- 9.6)pmol/L and Kd2 = (1,019 +/- 172)pmol/L. Albumin monomer was unable to compete for the polymerized albumin receptor sites on HepG2 cells. Anti-pre-S2 antibodies inhibit hepatitis B virus and pre-S2 binding to hepatocyte by 40% and 70%, respectively. Added extraneous polymerized albumin and the antibody against it did not interfere with virus attachment to HepG2 cells.

The effect of a mercurial ayurvedic drug (kajyoli), on the concentration of Na+, K+ and Ca2+ in rat liver, kidney and brain, and on the respiratory activity of these tissues is reported. The doses used were 20 mg and 40 mg X day-1 X kg-1 body wt. daily for 30 days, the lower level being equivalent to the human dose. A marked dose-dependent decrease in respiratory activity occurred in the three tissues. The only significant changes seen in the ion concentration were a decrease in Na+ at the higher dose level in the kidney and a dose-dependent decrease in Ca2+ in the liver.