Microplastic identification and quantification from organic rich sediments: A validated laboratory protocol.

Plastic pollution presents a global environmental concern with potentially widespread ecological, socio-economic and health implications. Methodological advances in microplastic extraction, quantification and identification from sediments have been made. However, integrating these fragmentary advances into a holistic, cost-effective protocol and applying it to organic rich sediments with fine grain size remains a challenge. Nonetheless, many hot spots of microplastic contamination such as harbour and estuarine sediments are characterised by such sediments. We conducted a series of experiments to integrate methodological advances, and clarify their applicability to organic rich sediments with fine grain size. The resulting protocol consisted of three stages. First, pre-treatment with Fenton's reagent was found to be efficient in reducing organic matter content, compatible with later Fourier Transform-Infrared Spectroscopy (FT-IR) for polymer identification, although it did affect the size of polyethylene (PE) and polyethylene terephthalate (PET). Secondly, a novel density separation column with a top overflow (the OC-T) obtained recovery rates above 90% for microplastics present in a ZnCL2 solution. Finally, automated epifluorescence microscopic image analysis of Nile Red stained filters with selected validation of polymer identities using FT-IR revealed 91.7% of stained particles to be plastics. A case study on estuarine sediments demonstrated a high extraction efficiency with quantification possible down to 125 µm and detection possible down to 62.5 µm. This makes this protocol suitable for large scale monitoring of microplastics in sediments of estuarine origin provided polymer specific recovery rates, background contamination and uncertainty in Nile Red identification is accounted for. Subject to further validation, the protocol could also offer a solution to similar organic rich sediments with fine grain size, such as some soils and sludge, to improve our ability to conduct cost-effective, large scale monitoring of microplastic contamination.

Taurine preserves gap junctional intercellular communication in rat hepatocytes under oxidative stress.

Gap junctional intercellular communication (GJIC) between hepatocytes is important for the maintenance of differentiated liver functions. Taurine is known to be cytoprotective, and is used clinically to improve liver functions. We evaluated the effect of taurine on GJIC in hepatocyte doublets under oxidative stress. Hepatocyte doublets were isolated from female Wistar rats, using a collagenase perfusion technique, and cultured in Leibovitz-15 medium containing fetal bovine serum (10%). H2O2 (2 mM) and/or taurine (0.1-1 mM) were added 2 h after inoculation, and the culture was incubated for 3 h. Fluorescent dye (Lucifer Yellow CH) coupling between adjacent cells was evaluated by microinjection. The distribution and quantity of connexin 32 (Cx32) in hepatocytes were detected using indirect immunofluorescence analysis and Western blotting. Steady state mRNA levels of Cx32 were detected by Northern blotting. The percentage of dye coupling 5 h after inoculation was 88 +/- 6.3% in the control. however, this was decreased to almost half the control value by H2O2. Taurine prevented the decrease caused by H2O2 in a dose-dependent manner. Immunofluorescence analysis for Cx32 demonstrated numerous punctate fluorescent spots along the intercellular plasma membrane in controls, which were significantly decreased by H2O2. Taurine prevented the decrease of Cx32. Western blot analysis also showed the decrease of Cx32 protein levels by H2O2 treatment, which decrease was prevented by taurine. Interestingly, H2O2 and/or taurine treatments did not affect Cx32 mRNA levels. Our findings indicated that H2O2 treatment decreased GJIC between hepatocytes, most likely due to augmenting the degradation of Cx32 proteins, whereas taurine prevented this process. This effect of taurine is beneficial for the preservation of differentiated functions in the liver under oxidative stress.

[Clinical evaluation of lenampicillin in oral and maxillofacial infections].

Clinical efficacies of newly developed synthetic oral ampicillin prodrug lenampicillin (LAPC, KBT-1585) applied to 109 cases of oral infection were studied. There were 7 dropout cases. The results as determined on a point system are as follow: Remarkably effective, 26 cases; effective, 63 cases; and not effective, 13 cases, for an efficacy rate of 87.3%. When rated by the subjective judgement of the doctors in charge, these figures are as follow: remarkably effective, 21 cases, effective, 67 cases; slightly effective, 10 cases; and not effective, 4 cases. The rate of efficacy in this way being 86.3%. In either way, the results obtained were favorable. Among 102 cases in this study, pus was aspirated with sterile needle from obstructed abscesses in 65 cases, with the result that 161 strains of bacteria were isolated and identified. Most of infections were found mixed type by aerobic Gram-positive cocci and anaerobes. Especially, cases caused by alpha-Streptococcus were observed in 48 out of 55 mixed infective cases. LAPC's MIC distribution against the detected bacteria showed strong antibacterial effect as follows: against Gram-positive cocci, less than 0.39 micrograms/ml; against Gram-negative bacteria (excluding some insusceptible strains), less than 3.13 micrograms/ml. Thus, LAPC demonstrated a superiority when compared to CEX by 4 approximately 128-fold, and when compared to AMPC by about 2-fold. Adverse reactions among the 109 cases consisted of 6 cases of gastro-intestinal disorders including 3 cases of diarrhea. Recognized cases of abnormal laboratory findings were 3 cases out of 76 (3.9%), but none were serious.

Leptin augments inflammatory and profibrogenic responses in the murine liver induced by hepatotoxic chemicals.

Lines of evidence suggested a possible link between leptin and hepatic fibrosis; however, whether leptin modulates the fibrogenesis in the liver remains unclear. The purpose of this study, therefore, was to evaluate the effect of leptin on inflammatory and profibrogenic responses in the liver caused by hepatotoxic chemicals. Male C57Bl/6 mice were given carbon tetrachloride (CCl(4)) (0.1 microL/g body weight [BW], intraperitoneally [IP]) and/or recombinant murine leptin (1 microg/g BW, IP) simultaneously, and sacrificed up to 72 hours later. Further, some mice were given thioacetamide (TAA; 200 microg/g BW, IP) and leptin 3 times per week for 4 weeks to evaluate the effect of leptin on chronic fibrogenic responses. A simultaneous injection of leptin enhanced acute CCl(4)-induced necroinflammatory and subsequent fibrotic changes in the hepatic lobules. The steady-state messenger RNA (mRNA) levels of alpha1(I) procollagen and heat shock protein 47 (HSP47) in the liver were potentiated when leptin was injected together with CCl(4). Expression of alpha smooth muscle actin (alpha-SMA) in the liver after CCl(4) treatment was also augmented markedly in combination with leptin. Further, leptin increased transforming growth factor beta1 (TGF-beta1) mRNA in the liver 24 hours after acute CCl(4) about 4-fold higher than CCl(4) alone. Moreover, leptin enhanced hepatic fibrosis and induction of alpha1(I) procollagen mRNA caused by chronic TAA administration. Collectively, these findings indicated that leptin augments both inflammatory and profibrogenic responses in the liver caused by hepatotoxic chemicals. It is postulated that the increase in systemic leptin levels enhances up-regulation of TGF-beta1, leading to activation of stellate cells, thereby augmenting the fibrogenic response in the liver.

Glycine prevents apoptosis of rat sinusoidal endothelial cells caused by deprivation of vascular endothelial growth factor.

Apoptosis of sinusoidal endothelial cells (SECs) is one of the initial events in the development of ischemia-reperfusion injury of the liver. Glycine has been shown to diminish ischemia-reperfusion injury in the liver and improve graft survival in the rat liver transplantation model. Here, we investigated the effect of glycine on apoptosis of primary cultured rat SECs induced by vascular endothelial growth factor (VEGF) deprivation. Isolated rat SECs were cultured in EBM-2 medium supplemented with 10% fetal bovine serum (FBS) and growth factors including 20 ng/mL VEGF for 3 days. SECs at 3 days of culture showed spindle-like shapes; however, cells started shrinking and detaching from dishes by VEGF deprivation. Apoptosis was detected by terminal deoxynucleotidyl transferase (TdT)-mediated d-uridine triphosphate (dUTP)-biotin nick end labeling (TUNEL) staining in these conditions. Control SECs contained only a few percent of TUNEL-positive cells; however, they started increasing 4 hours after VEGF deprivation, and the percentage of TUNEL-positive cells reached about 50% at 8 hours and almost 100% at 16 hours after VEGF deprivation. Interestingly, this increase in TUNEL-positive cells after VEGF deprivation was prevented significantly when glycine (1-10 mmol/L) was added to the medium, the levels being around 60% of VEGF deprivation without glycine. Furthermore, strychnine (1 micromol/L), a glycine receptor antagonist, inhibited this effect of glycine, suggesting the possible involvement of the glycine receptor/chloride channel in the mechanism. Moreover, Bcl-2 protein levels in SECs were decreased 8 hours after VEGF deprivation, which was prevented almost completely by glycine. It is concluded that glycine prevents apoptosis of primary cultured SECs under VEGF deprivation.

Tolerance and sensitization to endotoxin in Kupffer cells caused by acute ethanol involve interleukin-1 receptor-associated kinase.

Ethanol changes sensitivity of Kupffer cells to endotoxin. Here, the hypothesis that interleukin-1 receptor-associated kinase (IRAK), a downstream signaling molecule of toll-like receptors, regulates the response to LPS in Kupffer cells after ethanol treatment was evaluated. C57BL/6 mice were given ethanol intragastrically, and LPS was injected 1 or 21 h later. One hour after ethanol treatment, serum transaminases after LPS were 60% of control, while ethanol increased these parameters about 3-fold 21 h after ethanol. Pretreatment with antibiotics blocked these effects of ethanol. In Kupffer cells from mice treated with ethanol 1 h earlier, LPS-induced TNFalpha production, and IRAK expression and activity and NFkappaB were decreased 50-60% of control. In contrast, in Kupffer cells from mice treated with ethanol 21 h earlier, LPS-induced TNFalpha production, expression and activity of IRAK were increased 1.5-fold over controls, while NFkappaB was elevated 3-fold. These data indicate that ethanol-induced tolerance and sensitization of Kupffer cells to endotoxin in mice involve IRAK.

Kupffer cells contain a glycine-gated chloride channel.

Here the effect of glycine on intracellular Ca2+ concentration ([Ca2+]i) in cultured Kupffer cells stimulated with lipopolysaccharide (LPS) was investigated to assess the possibility that they contain a glycine-gated chloride channel. LPS (10 micrograms/ml) increased [Ca2+]i rapidly, with peak values reaching 307 +/- 29 nM. Glycine (1 mM) prevented this increase nearly completely. Low concentrations of strychnine (1 microM), a glycine receptor antagonist, reversed the inhibitory effect of glycine completely; however, high concentrations of strychnine (1 mM) mimicked glycine. The effects of glycine and high-dose strychnine were prevented when cells were incubated in chloride-free buffer. Furthermore, potassium (25 mM) and LPS depolarized the Kupffer cell plasma membrane, whereas glycine caused hyperpolarization and prevented depolarization due to potassium and LPS. Moreover, tumor necrosis factor-alpha (TNF-alpha) production in cultured Kupffer cells due to LPS was decreased significantly by glycine. Therefore, it is concluded that Kupffer cells contain a glycine-gated chloride channel similar to that described previously in the central nervous system. Prevention of increases in [Ca2+]i due to LPS by activation of chloride influx reduced synthesis and release of toxic mediators by Kupffer cells.

Hepatocyte growth factor inhibits intercellular communication via gap junctions in rat hepatocytes.

We demonstrated that HGF reduces gap junctional intercellular communication of rat hepatocyte doublets and increases cell spreading. Intercellular communication via gap junctions was markedly reduced in hepatocyte doublets with HGF (20 ng/ml) 3-12 hr after inoculation. Immunocytochemistry revealed spotty localization of connexin 32 on the plasma membrane of 3-hr cultured control hepatocyte doublets, whereas HGF-treated doublets showed significantly less connexin 32 staining. Genistein maintained intercellular communication in the presence of HGF, indicating that HGF reduces intercellular communication by down regulation of connexin 32 through the c-met/HGF receptor-tyrosine-kinase-mediated pathway. Furthermore, TGF-beta 1 maintained intercellular communication in the presence of HGF. Regulation of intercellular communication in hepatocytes by HGF and TGF-beta 1 might play an important role during liver regeneration.

Nimodipine, a dihydropyridine-type calcium channel blocker, prevents alcoholic hepatitis caused by chronic intragastric ethanol exposure in the rat.

It has been shown recently that inactivation of Kupffer cells prevents free radical formation and early alcohol-induced liver injury, and that hypoxia subsequent to a hypermetabolic state caused by activated Kupffer cells is likely involved in the mechanism. Calcium is essential for the activation of Kupffer cells, which contain L-type voltage-dependent Ca2+ channels. Therefore, the purpose of this study was to determine whether a Ca2+ channel blocker, nimodipine, prevents early alcohol-induced liver injury in vivo and to evaluate its effect on intracellular calcium ([Ca2+]i) in Kupffer cells in vitro. Male Wistar rats were exposed to ethanol (10-12 g/kg/d) continuously for up to 4 weeks via intragastric feeding using an enteral model developed by Tsukamoto and French. In this model, ethanol causes steatosis, necrosis, and inflammation in only a few weeks. In the experimental group, nimodipine (10 mg/kg/d) was added to the diet and was shielded from direct light. Nimodipine had no effect on body weight over a 4-week treatment period, nor were mean ethanol concentrations or their cyclic pattern in urine affected. The mean urine ethanol values were 154 +/- 11 mg/dL in ethanol-fed and 144 +/- 38 mg/dL in ethanol + nimodipine-fed rats. After 4 weeks, serum aspartate transaminase (AST) levels were elevated in ethanol-treated rats to 183 +/- 78 U/L. In contrast, values only reached 101 +/- 9 U/L in rats given nimodipine + ethanol-values which were significantly lower. Steatosis and necrosis assessed histologically were also reduced significantly by nimodipine. Nimodipine (10 micrograms/kg) also blocked the swift increase in alcohol metabolism and elevated oxygen consumption in perfused livers from rats treated with alcohol in vivo. Further, in cultured Kupffer cells, nimodipine (1 mumol/L) largely prevented the elevation in [Ca2+]i caused by lipopolysaccharide (LPS) (LPS, 200 +/- 11 nmol/L; LPS + nimodipine, 94 +/- 31 nmol/L; P < .05). These results indicate that nimodipine prevents alcoholic hepatitis, possibly by inhibition of endotoxin-mediated Kupffer cell activation.

A diet containing glycine improves survival in endotoxin shock in the rat.

In this study, we investigated the effects of a glycine-containing diet (5%) on mortality and liver injury due to intravenous injection of endotoxin [Escherichia coli lipopolysaccharide (LPS)] in Sprague-Dawley rats in vivo. Fifty percent of the rats fed control diet died within 24 h after an intravenous injection of LPS (10 mg/kg), whereas feeding the rats glycine totally prevented mortality and markedly reduced an LPS-induced elevation of serum transaminase levels, hepatic necrosis, and lung injury. The elevation in serum tumor necrosis factor-alpha (TNF-alpha) due to LPS was also blunted and delayed significantly by glycine feeding. In a two-hit model (hepatic ischemia-reperfusion and injection of sublethal LPS), all rats fed control diet died, whereas 83% of glycine-fed animals survived with a significant reduction in transaminases and improved liver and lung histology. LPS elevated intracellular Ca2+ concentration ([Ca2+]i) in cultured Kupffer cells, an effect blocked almost completely by glycine. Glycine most likely reduces injury and mortality by preventing the LPS-induced elevation of [Ca2+]i in Kupffer cells, thereby minimizing toxic eicosanoid and cytokine production.

Pronase destroys the lipopolysaccharide receptor CD14 on Kupffer cells.

CD14 is a lipopolysaccharide (LPS) receptor distributed largely in macrophages, monocytes, and neutrophils; however, the role of CD14 in activation of Kupffer cells by LPS remains controversial. The purpose of this study was to determine if different methods used to isolate Kupffer cells affect CD14. Kupffer cells were isolated by collagenase (0.025%) or collagenase-Pronase (0.02%) perfusion and differential centrifugation using Percoll gradients and cultured for 24 h before experiments. CD14 mRNA was detected by RT-PCR from Kupffer cell total RNA as well as from peritoneal macrophages. Western blotting showed that Kupffer cells prepared with collagenase possess CD14; however, it was absent in cells obtained by collagenase-Pronase perfusion. Intracellular calcium in Kupffer cells prepared with collagenase was increased transiently to levels around 300 nM by addition of LPS with 5% rat serum, which contains LPS binding protein. This increase in intracellular calcium was totally serum dependent. Moreover, LPS-induced increases in intracellular calcium in Kupffer cells were blunted significantly (40% of controls) when cells were treated with phosphatidylinositol-specific phospholipase C, which cleaves CD14 from the plasma membrane. However, intracellular calcium did not increase when LPS was added to cells prepared by collagenase-Pronase perfusion even in the presence of serum. These cells were viable, however, because ATP increased intracellular calcium to the same levels as cells prepared with collagenase perfusion. Tumor necrosis factor-alpha (TNF-alpha) mRNA was increased in Kupffer cells prepared with collagenase perfusion 1 h after addition of LPS, an effect potentiated over twofold by serum; however, serum did not increase TNF-alpha mRNA in cells isolated via collagenase-Pronase perfusion. Moreover, treatment with Pronase rapidly decreased CD14 on mouse macrophages (RAW 264.7 cells) and Kupffer cells. These findings indicate that Pronase cleaves CD14 from Kupffer cells, whereas collagenase perfusion does not, providing an explanation for why Kupffer cells do not exhibit a CD14-mediated pathway when prepared with procedures using Pronase. It is concluded that Kupffer cells indeed contain a functional CD14 LPS receptor when prepared gently.

Differential Ca2+ signaling in neonatal and adult rat hepatocyte doublets.

BACKGROUND/AIMS: Intracellular Ca2+ ([Ca2+]i) is important in various cellular functions, including cellular proliferation and differentiation. To elucidate the relationship between [Ca2+]i oscillations and physiological hepatocyte proliferation, phenylephrine-evoked [Ca2+]i responses were sequentially investigated using short-term cultured hepatocyte doublets obtained from 1-, 3-, 6- and 8-week-old rats. METHODS/RESULTS: DNA synthesis in hepatocytes, determined by BrdU incorporation, was approximately 20% in 1-week-old rats, and decreased to <1% as the rats aged. Correspondingly, [Ca2+]i responses evoked by 10 micromol/l phenylephrine in hepatocyte doublets shifted from transient to sinusoidal-type [Ca2+]i oscillations and then to a sustained increase in [Ca2+]i, followed by a gradual return to baseline. The incidence of [Ca2+]i oscillations was 100+/-0.0%, 83.3+/-16.7%, 38.7+/-0.6% and 5.5+/-5.0% in 1-, 3-, 6- and 8-week-old rats, respectively. Removal of extracellular Ca2+ did not abolish [Ca2+]i oscillations, indicating that [Ca2+]i oscillations were caused primarily by Ca2+ mobilization from internal sites of the cells. The [Ca2+]i level in each of the adjacent cells was synchronous in sustained increase in [Ca2+]i, but asynchronous in [Ca2+]i oscillations. In proliferating doublets obtained from 1-week-old rats, the frequency of oscillations increased in a dose-dependent manner for phenylephrine concentrations of 1 to 100 micromol/l. CONCLUSIONS: Phenylephrine-evoked [Ca2+]i oscillations were directly related to hepatocyte proliferation and were mediated by frequency modulation. These results suggest that phenylephrine-evoked [Ca2+]i oscillations may contribute to cell-cycle progression of hepatocytes in physiological liver growth.

Sex difference in alcohol-related organ injury.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Nobuhiro Sato and Kai O. Lindros. The presentations were (1) Sex differences in ethanol pharmacokinetics, by E. Baraona; (2) Estrogen regulates the sensitivity to endotoxin in hepatic Kupffer cells, by K. Ikejima; (3) Sex difference in alcohol-related organ injury, by E. Mezey; (4) Aggravated ethanol-induced liver injury in female rats: Protection by the antiestrogen toremifene, by Harri A. Järveläinen; and (5) Alcohol metabolism in Asian subjects: Sex differences and flushing response, by V. A. Ramchandani.

Long-term alcohol exposure changes sensitivity of rat Kupffer cells to lipopolysaccharide.

BACKGROUND: Chronic ethanol treatment enhances Kupffer cell sensitivity to lipopolysaccharide (LPS). In this model, CD14 in Kupffer cells was increased significantly 4 weeks after ethanol. Moreover, it was shown that prostaglandin E2 produced by activated Kupffer cells participated in the mechanism of ethanol-induced fatty liver. This study was designed to elucidate the temporal effect of chronic ethanol exposure on Kupffer cell sensitization to LPS. METHODS: Rats were given ethanol every 24 hr intragastrically for up to 12 weeks, and Kupffer cells were isolated 24 hr after the final ethanol administration and cultured in RPMI 1640 with 10% fetal bovine serum. After addition of LPS to Kupffer cells, intracellular calcium ([Ca2+]i) was measured. RESULTS: CD14 in Kupffer cells was increased approximately 2-fold, and then it decreased and returned to control levels. The LPS-induced increases in [Ca2+]i and tumor necrosis factor-alpha by Kupffer cells were also increased approximately 3-fold over control values, but they also returned to control levels. Triglyceride content increased with the duration of chronic ethanol treatment. At 8 weeks, prostaglandin E2 produced by Kupffer cells increased approximately 3-fold over control values and triglycerides by approximately 4-fold before gradually decreasing to basal levels. After 12 weeks of ethanol exposure, LPS-induced increases in [Ca2+]i and tumor necrosis factor-alpha production were only approximately 50% as high as peak levels at 4 weeks. Liver triglyceride content at 12 weeks was reduced significantly compared with values at 8 weeks. CONCLUSIONS: Kupffer cells at the early stage of chronic ethanol exposure exhibited sensitization to LPS, but this sensitivity was blunted later. This correlated with triglyceride accumulation in the liver. These data indicate that long-term alcohol exposure changes the sensitivity of rat Kupffer cells to LPS but that the magnitude of the effect is time dependent.

Alcohol enhances lipopolysaccharide-induced increases in nitric oxide production by Kupffer cells via mechanisms dependent on endotoxin.

BACKGROUND: Ethanol causes both tolerance and sensitization of Kupffer cells. Accordingly, this study examines the effect of acute ethanol consumption on nitric oxide (NO) production from Kupffer cells with or without lipopolysaccharide (LPS) treatment. METHODS: Rats were given ethanol (4 g/kg body weight) intragastrically, and Kupffer cells were isolated 2 and 24 hr later. Some rats were treated for 4 days with 150 mg/kg/day of polymyxin B and 450 mg/kg/day of neomycin to prevent growth of intestinal bacteria, the primary source of endotoxin in the gastrointestinal tract. After addition of LPS, NO was measured by the Griess reaction. RESULTS: Two hours after ethanol administration, LPS-induced NO production by Kupffer cells was diminished by 50% but was enhanced 2-fold at 24 hr. Sterilization of the gut with antibiotics blocked this enhancement. CONCLUSIONS: Kupffer cells isolated from rats early after ethanol exhibited tolerance to LPS, whereas sensitization was observed later. It is likely that sensitization to Kupffer cell is caused by gut-derived endotoxin.

Glycine-gated chloride channels in neutrophils attenuate calcium influx and superoxide production.

Recently, it was demonstrated that liver injury and TNF-alpha production as a result of endotoxin (lipopolysaccharide, LPS) were attenuated by feeding animals a diet enriched with glycine. This phenomenon was shown to be a result of, at least in part, activation of a chloride channel in Kupffer cells by glycine, which hyperpolarizes the cell membrane and blunts increases in intracellular calcium concentrations ([Ca(2+)](i)) similar to its action in the neuron. It is well known that hepatotoxicity due to LPS has a neutrophil-mediated component and that activation of neutrophils is dependent on increases in [Ca(2+)](i). Therefore, the purpose of this study was to determine if glycine affected agonist-induced increases in [Ca(2+)](i) in rat neutrophils. The effect of glycine on increases in [Ca(2+)](i) elicited either by the bacterial-derived peptide formyl-methionine-leucine-phenylalanine (FMLP) or LPS was studied in individual neutrophils using Fura-2 and fluorescence microscopy. Both FMLP and LPS caused dose-dependent increases in [Ca(2+)](i), which were maximal at 1 microM FMLP and 100 microgram/ml LPS, respectively. LPS increased intracellular calcium in the presence and absence of extracellular calcium. Glycine blunted increases in [Ca(2+)](i) in a dose-dependent manner with an IC(50) of approximately 0.3 mM, values only slightly higher than plasma levels. Glycine was unable to prevent agonist-induced increases in [Ca(2+)](i) in chloride-free buffer. Moreover, strychnine (1 microM), an antagonist of the glycine-gated chloride channel in the central nervous system, reversed the effects of glycine (1 mM) on FMLP- or LPS-stimulated increases in [Ca(2+)](i). To provide hard evidence for a glycine-gated chloride channel in the neutrophil, the effect of glycine on radioactive chloride uptake was determined. Glycine caused a dose-dependent increase in chloride uptake into neutrophils with an ED(50) of approximately 0.4 mM, an effect also prevented by 1 microM strychnine. Glycine also significantly reduced the production of superoxide anion from FMLP-stimulated neutrophils. Taken together, these data provide clear evidence that neutrophils contain a glycine-gated chloride channel that can attenuate increases in [Ca(2+)](i) and diminish oxidant production by this important leukocyte.

Alcohol causes both tolerance and sensitization of rat Kupffer cells via mechanisms dependent on endotoxin.

BACKGROUND & AIMS: Ethanol causes both tolerance and sensitization of Kupffer cells. This study was designed to evaluate temporal effects of ethanol in an attempt to understand this paradox. METHODS: Rats were given ethanol (4 g/kg body wt) intragastrically, and Kupffer cells were isolated 0-48 hours later. After addition of lipopolysaccharide (LPS), intracellular calcium concentration ([Ca2+]i) was measured using a microspectrofluorometer with the fluorescent indicator fura-2, and tumor necrosis factor alpha (TNF-alpha) was measured by enzyme-linked immunosorbent assay. CD14 was evaluated by Western and Northern analysis. RESULTS: Two hours after ethanol administration, the LPS-induced increase in [Ca2+]i and TNF-alpha release by Kupffer cells was diminished by 50%, and these parameters were reciprocally enhanced twofold at 24 hours. Sterilization of the gut with antibiotics blocked all effects of ethanol on [Ca2+]i and TNF-alpha release completely. Twenty-four hours after ethanol, CD14 in Kupffer cells was elevated about fivefold. CONCLUSIONS: Kupffer cells isolated from rats early after ethanol exhibited tolerance to LPS, whereas sensitization was observed later. It is likely that both of these phenomena are caused by gut-derived endotoxin and that sensitization in Kupffer cells is caused by increases in CD14.

Marked retention of indocyanine green and sulfobromophthalein with chronic persistent hepatitis.

A hepatitis B virus (HBV) carrier with marked retention of indocyanine green (ICG) and sulfobromophthalein (BSP) was admitted to our hospital for assessment of liver function. On admission, he was asymptomatic and blood chemistry tests showed normal values for transaminases and bilirubin. Serum hepatitis B surface antigen (HBsAg) and antibody to hepatitis B e antigen (anti-HBe) were positive. A history of drug abuse or alcoholism was denied. Dye excretion tests revealed marked retention of ICG (R15 = 70%) and BSP (R45 = 23%). Histopathological examination of a liver biopsy specimen obtained during laparoscopic observation showed chronic persistent hepatitis (CPH). Familial research of the patient failed to prove the existence of dye excretory defect in his siblings. Usual cases of CPH due to continuous HBV infection do not show such severe disturbance of organic anion transport. This pattern of the dye excretory defect with CPH has not been reported. Although the relationship between this dye excretory defect and HBV infection is unclear, the existence of the constitutional dye excretory defect due to abnormal organic anion transport in the liver might be considered.

Kupffer cell sensitization by alcohol involves increased permeability to gut-derived endotoxin.

BACKGROUND: Studies with gut sterilization and Kupffer cell inactivation support the hypothesis that endotoxin and Kupffer cells are involved in mechanisms of alcohol-induced liver injury. Recently, we found that Kupffer cells isolated from rats treated only once with ethanol were sensitized to endotoxin 24 hr later. Moreover, we established a new, simple animal model of ethanol hepatotoxicity based on Kupffer cell sensitization. The purpose of this study was to determine the mechanisms by which alcohol sensitizes Kupffer cells to lipopolysaccharide (LPS). METHODS: Female Wistar rats were given ethanol (5 g/kg body weight) once every 24 hr intragastrically, and ethanol concentration, ethanol elimination, and portal vein endotoxin were measured. Gut permeability was measured in isolated segments of ileum by translocation of horseradish peroxidase. Kupffer cells were isolated 24 hr after ethanol administration in vivo and were cultured in RPMI 1640 with 10% fetal bovine serum. After the addition of LPS, intracellular Ca2+ was measured by using a microspectrofluorometer with the fluorescent indicator fura-2, and tumor necrosis factor (TNF)-alpha was measured by enzyme-linked immunosorbent assay. CD14 was evaluated by Western analysis. RESULTS: Ethanol levels exhibited a cyclic pattern in ethanol-treated rats. Similar results were obtained in groups given ethanol and antibiotics for 4 weeks. Rates of alcohol elimination were around 3.5 mmol/kg/hr in control rats. After 4 weeks of ethanol treatment with or without antibiotics, elimination rates were not changed. Translocation of horseradish peroxidase was increased about 3-fold in gut segments by treatment with ethanol. This increase was not altered by treatment with antibiotics. Moreover, portal vein endotoxin levels were increased from nearly undetectable levels to 80 pg/ml in plasma of rats treated with ethanol. As expected, this increase was prevented (<20 pg/ml) by antibiotics. In isolated Kupffer cells from rats treated with ethanol for 4 weeks, CD14, LPS-induced intracellular Ca2+, and TNF-alpha all were increased. These phenomena were blocked by antibiotics. CONCLUSIONS: Kupffer cells isolated from rats treated with ethanol for 4 weeks exhibit sensitization to LPS. It is likely that increased permeability of the gut is a prominent event that leads to alcoholic liver injury.