Near field optical microscopy in aqueous solution: implementation and characterization of a vibrating probe

Near field optical microscopy (NSOM) is one of the possible solutions to circumvent the diffraction limit, but the control of the optical probe in solution has been a technical challenge for practical applications. Most recently, it has been shown that the pipette used in the scanning ion conductance microscope can be modified to form a high resolution near field optical probe. When combined with a novel distance modulation mechanism, a robust near field microscope can be constructed for operation in aqueous solution. In this paper, we present technical details of this design and a further characterization of the NSOM system for imaging in solution. Fundamental limitations of this approach in comparison to other systems are also discussed. Based on the current technology, it is concluded that better than 50 nm resolution should be achievable with this technique for fluorescence, as well as fluorescence resonance energy transfer, imaging of biological specimens.

A 12-amino-acid segment, present in type s2 but not type s1 Helicobacter pylori VacA proteins, abolishes cytotoxin activity and alters membrane channel formation

Helicobacter pylori, a gram-negative bacterium associated with gastritis, peptic ulceration, and gastric adenocarcinoma in humans, secretes a protein toxin, VacA, that causes vacuolar degeneration of epithelial cells. Several different families of H. pylori vacA alleles can be distinguished based on sequence diversity in the "middle" region (i.e., m1 and m2) and in the 5' end of the gene (i.e., s1 and s2). Type s2 VacA toxins contain a 12-amino-acid amino-terminal hydrophilic segment, which is absent from type s1 toxins. To examine the functional properties of VacA toxins containing this 12-amino-acid segment, we analyzed a wild-type s1/m1 VacA and a chimeric s2/m1 VacA protein. Purified s1/m1 VacA from H. pylori strain 60190 induced vacuolation in HeLa and Vero cells, whereas the chimeric s2/m1 toxin (in which the s1 sequence of VacA from strain 60190 was replaced with the s2 sequence from strain Tx30a) lacked detectable cytotoxic activity. Type s1/m1 VacA from strain 60190 formed membrane channels in a planar lipid bilayer assay at a significantly higher rate than did s2/m1 VacA. However, membrane channels formed by type s1 VacA and type s2 VacA proteins exhibited similar anion selectivities (permeability ratio, P(Cl)/P(Na) = 5). When an equimolar mixture of the chimeric s2/m1 toxin and the wild-type s1/m1 toxin was added to HeLa cells, the chimeric toxin completely inhibited the activity of the s1/m1 toxin. Thus, the s2/m1 toxin exhibited a dominant-negative phenotype similar to that of a previously described mutant toxin, VacA-(Delta6-27). Immunoprecipitation experiments indicated that both s2/m1 VacA and VacA-(Delta6-27) could physically interact with a c-myc epitope-tagged s1/m1 VacA, which suggests that the dominant-negative phenotype results from the formation of heterooligomeric VacA complexes with defective functional activity. Despite detectable differences in the channel-forming activities and cytotoxic properties of type s1 and type s2 VacA proteins, the conservation of type s2 sequences in many H. pylori isolates suggests that type s2 VacA proteins retain an important biological activity.

[A case of ovarian cancer with metastatic tumor in the liver with paclitaxel and carboplatin systemic chemotherapy was very effective]

An 82-year-old woman was admitted to the Dept. of Obstetrics and Gynecology, Yamanashi Medical University to try to identify the origin of a liver metastatic tumor. CT examination revealed a small tumor located adjacent to the uterine cervix in a cul-de-sac. With biopsy using MR, it was clearly shown histologically that the origin of the tumor was the ovary. Systemic chemotherapy with paclitaxel and carboplatin was selected as the most reasonable treatment for this case because of the patient's age. After 6 courses of this chemotherapy, the tumor in the cul-de-sac disappeared and the tumor in the liver decreased markedly. Furthermore, no severe side effects were seen during this treatment. This result indicated that systemic chemotherapy with paclitaxel and carboplatin is effective and safe in cases of advanced ovarian cancer.

Potential value of CML-Hb in predicting the progression of bone cysts in dialysis-related amyloidosis

BACKGROUND/AIM

Carboxymethyllysine is one of the common advanced glycation end products in vivo. In a previous report, we were the first to describe the increase of circulating carboxymethyllysine-hemoglobin (CML-Hb) levels in hemodialysis patients, particularly in patients with dialysis-related amyloidosis (DRA). The aim of this study was to investigate the predictive value of CML-Hb in the progression of DRA using computed tomography images of 2-year or 3-year follow-up periods of patients with amyloid bone cysts at the hip joint.

METHODS

Circulating CML-Hb levels were measured as previously reported, and computed tomography scanning was conducted from 1996 to 1998 or 1999 in 57 hemodialysis patients whose original renal disease had been confirmed to be nondiabetic. Patients who showed a new growth of cysts or a growth rate of 30% or more were classified as progressive cases, while the other patients were classified as nonprogressive cases.

RESULTS

(1) The circulating CML-Hb levels showed a strong correlation with the DRA score by multiple regression analysis, and (2) patients with progression of amyloid cysts showed a significantly higher circulating CML-Hb level than patients without progression.

CONCLUSION

Based upon these results, we conclude that measurement of circulating CML-Hb levels has a potential value in both judgment of the clinical state and prediction of progression of DRA in hemodialysis patients.

Characterization of AC mode scanning ion-conductance microscopy

A scanning ion-conductance microscope (SICM) with a vibrating probe has been recently developed (vSICM). In this system, the amplitude of the AC ionic current is detected by using a lock-in amplifier locked to the vibration frequency of the probe. Such a scheme allows for a better control of the tip position because the AC ionic current is more sensitive to the probe-surface distance than the DC ionic current used previously. In this paper, we demonstrate the utility of this technique to the imaging of topographically rough specimens and high-resolution imaging over selected small areas. We also show that it is possible to record the DC ionic current simultaneously during the scan, which can reveal additional information not apparent in the images obtained with the AC ionic current.

Characterization of the metal-substituted dipeptidyl peptidase III (rat liver)

Dipeptidyl peptidase III (DPP III) (EC 3.4.14.4), which has a HELLGH-E (residues 450-455, 508) motif as the zinc binding site, is classified as a zinc metallopeptidase. The zinc dissociation constants of the wild type, Leu(453)-deleted, and E508D mutant of DPP III at pH 7.4 were 4.5 (+/-0.7) x 10(-13), 5.8 (+/-0.7) x 10(-12), and 3.2 (+/-0.9) x 10(-10) M, respectively. The recoveries of the enzyme activities by the addition of various metal ions to apo-DPP III were also measured, and Co(2+), Ni(2+), and Cu(2+) ions completely recovered the enzyme activities as did Zn(2+). The dissociation constants of Co(2+), Ni(2+), and Cu(2+) ions for apo-DPP III at pH 7.4 were 8.2 (+/-0.9) x 10(-13), 2.7 (+/-0.3) x 10(-12), and 1.1 (+/-0.1) x 10(-14) M, respectively. The shape of the absorption spectrum of Co(2+)-DPP III was very similar to that of Co(2+)-carboxypeptidase A or Co(2+)-thermolysin, in which the Co(2+) is bound to two histidyl nitrogens, a water molecule, and a glutamate residue. The absorption spectrum of Cu(2+)-DPP III is also very similar to that of Cu(2+)-thermolysin. The EPR spectrum and the EPR parameters of Cu(2+)-DPP III were very similar to those of Cu(2+)-thermolysin but slightly different from those of Cu(2+)-carboxypeptidase A. The five lines of the superfine structure in the perpendicular region of the EPR spectrum in Cu(2+)-DPP III suggest that nitrogen atoms should coordinate to the cupric ion in Cu(2+)-DPP III. All of these data suggest that the donor set and the coordination geometry of the metal ions in DPP III, which has the HExxxH motif as the metal binding site, are very similar to those of the metal ions in thermolysin, which has the HExxH motif.

Ischemic preconditioning attenuates cardiac sympathetic nerve injury via ATP-sensitive potassium channels during myocardial ischemia

BACKGROUND

During myocardial ischemia, massive norepinephrine (NE) is released from the cardiac sympathetic nerve terminals, reflecting the sympathetic nerve injury. A brief preceding ischemia can reduce infarct size; this is known as ischemic preconditioning (PC). The effect of PC on sympathetic nerves, however, including its underlying mechanisms in dog hearts, has remained unclear. Thus, this study was designed to elucidate whether the activation of ATP-sensitive potassium (K(ATP)) channels is involved in the mechanism of cardiac sympathetic nerve protection conferred by PC.

METHODS AND RESULTS

Interstitial NE concentration was measured by the in situ cardiac microdialysis method in 45 anesthetized dogs. Five minutes of ischemia followed by 5 minutes of reperfusion was performed as PC. In the controls, the dialysate NE concentration (dNE) increased 15-fold after the 40-minute ischemia. PC decreased dNE at 40-minute ischemia by 59% (P<0.01), which was reversed by glibenclamide. A K(ATP) channel opener, nicorandil (25 microg. kg(-1). min(-1) IV), decreased dNE at 40 minutes of ischemia by 76% (P<0.01), which was also reversed by glibenclamide. During the PC procedure, no significant increase in dNE was detected, even with the uptake-1 inhibitor desipramine.

CONCLUSIONS

Cardiac sympathetic nerve injury during myocardial ischemia was attenuated by PC via the activation of K(ATP) channels, but the trigger of the PC effect is unlikely to be NE release in dog hearts.

Protein kinase A increases the rate of relaxation but not the rate of tension development in skinned rat cardiac muscle

To clarify the contribution of cross-bridge kinetics to the contraction profile of cardiac twitch during beta-adrenergic stimulation, we studied the rate of tension development and relaxation following laser flash photolysis of caged compounds in rat-skinned ventricular trabeculae before and after treatment with the catalytic subunit of protein kinase A (PKA, 0.5 U/microl, 40 min). Tension development following nitrophenyl (NP)-EGTA photolysis was fitted with a single exponential function. The rate constant increased with an increase in postphotolysis steady tension, and the relation between the rate constant and the tension was not influenced by PKA. The rate of relaxation following diazo-2 photolysis was fitted with a double exponential function. The rate of both initial rapid and subsequent slow relaxation was independent of the extent of relaxation. PKA increased the rate of initial rapid relaxation by about twofold, but showed no significant effect on the rate of subsequent slow relaxation. These results suggest that in beta-receptor stimulated rat cardiac muscle, the increased rate of tension development and the facilitated relaxation rate during twitch can be partly explained as being due to the combined effects of decreased Ca(2+) affinity of troponin C and increased cycling rate of cross-bridges (subtractive combination for tension development and additive combination for tension relaxation).

S-myotrophin promotes the hypertrophy of myotube as insulin-like growth factor-I does

We have reported previously that a novel muscle cell growth factor, having a structure of a peptide with sugar chains, was successfully purified from porcine skeletal muscle. It was named s-myotrophin. To determine the role of s-myotrophin in skeletal muscle growth, the effect of s-myotrophin on primary cultured chick skeletal muscle cells (composed almost totally of multinucleated myotubes) was investigated by comparing s-myotrophin with Insulin-like growth factor-I (IGF-I). Both s-myotrophin and IGF-I significantly increased creatine kinase activity of the cultures; both substances gave similar responses. Intracellar protein content was also increased by the addition of these factors. The content of myosin and actin in s-myotrophin treated culture in the differentiation medium was significantly higher than that of the control (unstimulated). The content of those proteins in IGF-I treated culture was also higher than that of control, but the differences were not statistically significant. Immunoblot analysis confirmed that the amounts of myosin and actin in the myocytes were greatly increased by s-myotrophin stimulation and also by IGF-I stimulation. Morphological observations using an anti-desmin antibody staining procedure demonstrated that the size of both s-myotrophin and IGF-I treated myotubes was appreciably larger than that of control myotubes. These results suggest that s-myotrophin is a potent mediator of skeletal muscle cell hypertrophy thorough the accumulations of muscle structural proteins.

Immunochemical assay of hemoglobin with N(epsilon)-(carboxymethyl)lysine at lysine 66 of the beta chain

BACKGROUND

N(epsilon)-(Carboxymethyl)lysine (CML), a well-characterized and major advanced glycation end product structure, is produced via a Maillard reaction by nonenzymatic glycation and/or oxidation. Although few of the carboxymethylation sites of lysine residues on proteins have been identified, it is known that the possible lysine glycation site in hemoglobin (Hb) is Lys-66 on the beta chain. We aimed to develop an assay for the Hb with a CML (CML-Hb) site specific to Lys-66 on the Hb beta chain and to determine whether the lysine residue at that site is carboxymethylated.

METHODS

Ala-His-Gly-Lys-Lys(CM)-Val-Leu-Gly-Ala-Phe-Ser-Cys, the peptide derived from the beta chain of human Hb, was synthesized as an immunogen, and a monoclonal antibody against the peptide was prepared. A latex immunoassay method was established using the antibody on an automatic analyzer. In this study, 20 samples from healthy subjects and 80 samples from nondiabetic patients undergoing hemodialysis (HD) were analyzed.

RESULTS

The latex immunoassay method using the antibody correlated significantly with the ELISA method using the antibody (r = 0.95; P <0.001). Between healthy subjects (n = 20) and nondiabetic HD patients (n = 80), a significant difference was seen in circulating CML-Hb (525 +/- 76 vs 778 +/- 137 pmol CML/mg of Hb; P <0.0001).

CONCLUSION

The latex method for the CML-Hb site specific to Lys-66 on the beta chain can measure large numbers of samples on an automatic analyzer.

Scanning electron microscopic observation of the architecture of collagen fibres in chicken M. iliotibialis lateralis

1. The collagen architecture of M. iliotibialis lateralis in chicken was observed under the scanning electron microscope after muscle maceration in NaOH. 2. Immunohistochemical methods showed Type I and III collagens to be distributed over both perimysium and endomysium. 3. Thick perimysium around secondary myofibre fasciculi was composed of many large longitudinal collagen bundles and a few small circumferential bundles. In contrast, thin perimysium around primary myofibre fasciculi showed mainly circumferential bundles. 4. Endomysium had a honeycomb-like structure and consisted of a fine collagen mesh, its main fibre striation being circumferential. 5. It is suggested that functional demand differs between thick perimysium and thin endomysium.

Pirfenidone inhibits dimethylnitrosamine-induced hepatic fibrosis in rats

1. In the present study, we investigated the preventive effects of pirfenidone (PFD), an antifibrotic agent, on experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. 2. Treatment with DMN caused a significant decrease in bodyweight and liver weight. Oral PFD (500 mg/kg daily for 4 weeks) essentially prevented this DMN-induced loss in bodyweight and tended to suppress the loss in liver weight. There were no significant differences in liver weight and serum L-alanine aminotransferase levels between PFD-treated and -untreated groups. Pirfenidone has no major side effects in vivo. 3. Pirfenidone suppressed the induction of hepatic fibrosis determined by histological evaluation and reduced hepatic hydroxyproline levels. Expression of mRNA for type I collagen and transforming growth factor-beta in the liver was also suppressed by PFD treatment. 4. Because hepatic stellate cells (HSC) are the major cellular source of extracellular matrix in hepatic fibrosis, we examined the effects of PFD on type I collagen production in vitro using rat primary HSC cultures. Pirfenidone inhibited collagen production in HSC culture in a dose-dependent manner. 5. These results demonstrate that the inhibitory effects of PFD against hepatic fibrosis may be due, at least in part, to blockade of collagen production by HSC and suggest that PFD may be potentially useful in the prevention of the development of hepatic fibrosis.

Elevation of N-(carboxymethyl)valine residue in hemoglobin of diabetic patients. Its role in the development of diabetic nephropathy

OBJECTIVE

Advanced glycation end products (AGEs) are a risk factor for diabetic complications. We have developed an assay method for N-(carboxymethyl)valine (CMV) of the hemoglobin (CMV-Hb), which is an AGE generated from HbA1c. Herein we describe the clinical utility of CMV-Hb measurement for the diagnosis of diabetic nephropathy

RESEARCH DESIGN AND METHODS

BALB/c mice were immunized with carboxy-methylated Hb and monoclonal antibody raised against CMV-Hb. This antibody was characterized by a surface plasmon resonance. We developed a latex immunoassay using the antibody and measured CMV-Hb from erythrocytes in type 2 diabetic patients and healthy control subjects (age 64.6 +/- 12.0 vs. 61.1 +/- 13.2 years, NS: HbA1c 69 +/- 1.5 vs. 5.2 +/- 0.4%, P < 0.0001).

RESULTS

A monoclonal antibody against CMV-Hb beta-chain NH2-terminal and an assay method for measurement for CNMV-Hb were both developed in our laboratory. CMV-Hb levels were significantly greater in the diabetic patients than in the control subjects (18.2 +/- 6.9 vs. 12.7 +/- 0.9 pmol CMV/mg Hb, P < 0.0001). No correlation was found between CMV-Hb and HbA1c or CMV-Hb and glycated albumin. Levels of CMV-Hb increased as the diabetic nephropathy progressed.

CONCLUSIONS

We established an assay method for CMV-Hb and confirmed the presence of CMV-Hb in circulating erythrocytes. CMV-Hb was more prevalent in diabetic patients than in healthy subjects. Furthermore, it was significantly higher in patients with diabetic nephropathy, suggesting that the presence of CMV-Hb may be a valuable marker for the progression of diabetic nephropathy.

Hepatic epithelioid hemangioendothelioma

Epithelioid hemangioendothelioma (EHE) is a rare neoplasm of vascular origin with unpredictable malignant potential. We describe two patients with primary EHE of the liver and review 34 cases previously published in Japan and compare them with those in Western countries. The clinical aspects of EHE and relevant treatment results in Japanese patients were similar to those found in Western countries, the exception being the matter of difference in incidence between genders. Although this tumor type has been reported to be more frequent among women, there was no significant difference in incidence between men and women. Hepatic EHE generally behaves as a low-grade malignant tumor with a slow progression phenotype; however, this disease seems to be resistant to chemotherapy and to be lethal in some cases. Surgical resection or liver transplantation is recommended after rapid diagnosis by radiologic examination and histologic findings, including positive staining of tumor cells for factor VIII-related antigen.

A selective ROCK inhibitor, Y27632, prevents dimethylnitrosamine-induced hepatic fibrosis in rats

BACKGROUND

p160ROCK is a direct Rho target which mediates Rho-induced assembly of focal adhesions and stress fibers. We previously reported that Rho signaling pathways are involved in the activation of hepatic stellate cells (HSC) in vitro. The aim of the present study was to test the hypothesis that an inhibitor specific for p160ROCK (Y27632) could prevent experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats.

METHODS

Y27632 was given orally at 30 mg/kg daily for 4 weeks after the first injection of DMN. The degree of fibrosis was evaluated by image analysis and also by measurements of collagen and hydroxyproline content in the liver. The expression of alpha-smooth muscle actin (alpha-SMA) in the liver and in the primary cultured HSC was also evaluated. Semi-quantitative RT-PCR was performed to evaluate the expression of type I collagen mRNA in the liver.

RESULTS

Y27632 treatment significantly decreased the occurrence of DMN-induced hepatic fibrosis and reduced the collagen and hydroxyproline content and alpha-SMA expression in the liver. The expression of alpha-SMA in HSC was also suppressed in vitro.

CONCLUSIONS

These findings indicate that inhibitors of the Rho-ROCK pathway might be useful therapeutically in hepatic fibrosis.

Serum levels of HCV RNA and core protein before and after incubation at 37 degrees C for 24 h

The kinetics of HCV during interferon (IFN) therapy have recently been described and the estimated virion half-life is an average of 2.7 h, suggesting that HCV infection is highly dynamic. The aim of this study was to evaluate serum levels of HCV-RNA and HCV core protein (HCV-Ag) before and after incubation at 37 degrees C for 24 h. We also evaluated the viral kinetics during IFN treatment by determining their serum levels at 0, 24 and 48 h, and day 8 after the start of treatment. The decay slope was calculated as the logarithm of the ratio of HCV-RNA levels at 0 and 24 h of incubation: log(virus load) 24 h-log(virus load) 0 h and the estimated half-life was also calculated. The decay slope was -1.66+/-0.75 (-4.12 to -0.18) (mean+/-S.D. (range)) and the estimated virion half-life was 6.2+/-6.9 h (1.8-39.3). The HCV-RNA level was rapidly decreased to 6.8+/-13.1% of the initial load after incubation independently of the serotype. In contrast, the HCV-Ag level after incubation for 24 h was 98.7+/-12.2% of the initial level. The synthesized naked HCV-RNA (equivalent to 10(7) copy/ml) was not detected after 1-min incubation. These data suggested that HCV virions are very unstable and collapsed rapidly and that HCV-RNA, existing outside of virions, is immediately degraded in serum, whereas HCV-Ag remains stable. IFN treatment caused a rapid decrease in the levels of both HCV-RNA and HCV-Ag. The HCV-RNA decay slope was -1.95+/-0.96 (range: -3.48 to -0.50) and was similar to that seen in the incubation study. Our result suggested the significance of measuring HCV-Ag during clinical management independently of HCV-RNA, especially because of its high stability.

Serum leptin levels in patients with nonalcoholic chronic liver disease

BACKGROUND/AIMS

The elevated serum leptin level of patients with alcoholic cirrhosis has been reported, however, the precise mechanism is still unknown. Leptin expression and protein synthesis have also been detected in activated hepatic stellate cells in cell cultures, which play a major role in hepatic fibrosis. We evaluated the serum leptin levels of patients with nonalcoholic liver diseases including cirrhosis and chronic hepatitis. We also investigated the hepatic clearance of leptin by determining the serum leptin level in blood samples obtained from the portal and hepatic veins.

METHODOLOGY

The serum leptin level of 44 patients with nonalcoholic chronic liver disease (male/female = 21/23, cirrhosis/chronic hepatitis = 30/14) and 40 control subjects (male/female = 20/20) was determined in blood samples obtained from the antecubital vein by enzyme-linked immunosorbent assay. We also assessed the relationship between the leptin level and various biochemical tests of liver function. Additionally, we determined the leptin levels in the portal and the hepatic venous blood (nonalcoholic cirrhosis = 10, nonhepatic disease = 4).

RESULTS

There were positive correlations between the serum leptin level and body mass index among males and among females in the liver disease group and in the control group. However, the serum leptin level of the liver disease group and control group did not differ significantly. Among the 44 liver disease patients, only the serum cholesterol level was significantly correlated with the serum leptin level after adjusting for sex and body mass index by multiple regression analysis. Furthermore, the leptin level in hepatic venous blood was significantly lower than that in portal venous blood. However, the ratio of [leptin level in hepatic venous blood]/[leptin level in portal venous blood] in the cirrhosis group, and that in the nonhepatic disease group, did not significantly differ.

CONCLUSIONS

The serum leptin level of patients with nonalcoholic liver diseases is not elevated. On the other hand, the serum leptin level of patients with alcoholic cirrhosis has been reported to be elevated. The difference in the serum leptin level of patients with nonalcoholic liver disease and that of patients with alcoholic cirrhosis may be due to a difference in factors such as the levels of cytokines or sex steroids, and/or nutrition. Furthermore, it is likely that leptin is cleared in part by the portosystemic circulation through the liver.

The selenoorganic compound ebselen suppresses liver injury induced by Propionibacterium acnes and lipopolysaccharide in rats

Ebselen (2-phenyl-1,2-benzoisoselenazol-3[2H]-one) is a selenoorganic compound containing selenium that has various pharmacological effects, including anti-inflammatory and antioxidant activity. Kupffer cells, residual hepatic macrophages, play an important role in the development of liver injury by producing free radicals and cytokines. The aim of this study is to evaluate whether ebselen suppresses macrophage-associated liver injury in rats. In vivo, we examined the effects of ebselen on liver injury, induced by Propionibacterium acnes and lipopolysaccharide (P. acnes-LPS), in rats where hepatic macrophages are considered to be primarily involved in injury development. Ebselen administration reduced the incidence of death following hepatic failure by P. acnes-LPS (82% vs. 20%, p<0.05). Serum levels of alanine aminotransferase, at 5 h after LPS administration, were significantly lower in the ebselen-treated group than in the control group (202.4+/-100.3 IU/l vs. 558.4+/-146.4 IU/l, p<0.05). Histological evidence of injury, such as necrosis, hemorrhage, and degeneration, was also suppressed by ebselen. Further, to assess the mechanisms involved, we investigated the production of cytokines and superoxide anions produced by activated hepatic macrophages in vivo. Serum levels of TNF alpha, interleukin-18 (IL-18)/IFN gamma-inducing factor (IGIF), and interferon gamma (IFN gamma) at 1 h after LPS administration were significantly lower in the ebselen-treated group. Formazan depositions, which were generated by the perfusion of the liver with nitroblue tetrazolium, were also observed less frequently in the ebselen treated group, suggesting a suppression in the release of superoxide anion from activated hepatic macrophages. In addition, we examined the effects of ebselen on cytokine production and mRNA expression, in vitro, using rat primary Kupffer cell culture. Ebselen also inhibited TNF alpha production and mRNA expression in vitro. These data imply that ebselen suppresses liver injury by inhibiting the production and/or release of proinflammatory cytokines and superoxide from activated hepatic macrophages. These data also suggest that ebselen is potent in the prevention of hepatic injury, such as endotoxemia, where hepatic macrophage activation has been implicated.

Telomerase activity is repressed during differentiation along the hepatocytic and biliary epithelial lineages: verification on immortal cell lines from the same origin

Recent investigations indicate that telomerase activity regulates the life span of cells by compensating for telomere shortening during DNA replication. In addition, as differentiation progresses, telomerase activity is reduced in several different cell lineages. These findings lend support to the theory that more immature cells have greater remaining proliferative capacity and longer life span. However, it has not been directly demonstrated that the differentiation along a hepatocytic or a bile ductal lineage is accompanied by reduction of telomerase activity. In this study, we present direct evidence that telomerase activity is reduced during hepatocytic and biliary epithelial differentiation by using our unique cell lines including a stem-like cell line, ETK-1. When hepatocytic differentiation was induced in ETK-1 by 5-azacytidine, telomerase activity decreased significantly. Similarly, when we compared the telomerase activity on SSP-25 and RBE cell lines from the same origin but representing different maturation stages of cholangiocarcinoma, more mature cells were found to possess significantly lower activity. These results indicate that the generally accepted relationship between telomerase activity and differentiation stage also applies in the hepatocytic and biliary epithelial lineages.

Changes of cytokines in direct endotoxin adsorption treatment on postoperative multiple organ failure

Multiple organ failure (MOF) is a serious condition that involves simultaneous or consecutive functional failure of several important organs. Furthermore, sepsis is known to play an important role in the occurrence of MOF. Hemoadsorption therapy with the endotoxin adsorption column containing polymyxin B immobilized fibers by direct hemoperfusion (PMX-DHP) is reportedly effective in the treatment of septic shock. This study examined the changes induced on cytokines upon PMX-DHP treatment in 25 patients who underwent emergency abdominal surgery and were immediately started on a postoperative regimen of continuous hemodiafiltration (CHDF) and PMX-DHP. Postoperative MOF was observed in these patients with a mean APACHE II SCORE of 25.5. Eighty percent of patients survived for more than 1 month. We were able to reduce the necessary dose of dopamine in 85.7% of patients because hemodynamic stability improved after administration of PMX-DHP. Interleukin 6 blood levels did not change significantly before or after PMX-DHP treatment in either the surviving or nonsurviving patients. Blood interleukin 1 receptor antagonist levels decreased in both groups. Intercellular adhesion molecular-1, NOx, and thrombomodulin did not change significantly during the course of treatment in either group. Decreased blood levels of PAI-1 levels were found in the surviving patients whereas increased levels of PAI-1 were found in the non-surviving patients. In conclusion, PMX-DHP treatment may be limited clinically in its ability to remove inflammatory cytokines and humoral mediators. However, PMX-DHP treatment is useful for hemodynamic stabilization, which prevents development of MOF.

Prevalence of hepatitis B or C virus infections in patients with non-Hodgkin's lymphoma

BACKGROUND

Hepatitis C virus (HCV) and hepatitis B virus (HBV) are not only hepatotropic, but also lymphotropic viruses. Recently, some reports suggested that these viruses may participate in the development of malignant lymphoproliferative disorders.

METHODS

We investigated the prevalence of HCV or HBV infection in 348 patients with non-Hodgkin's lymphoma (NHL). We also compared these prevalences with those in blood donors as a control group representing the general population in our area (n= 1,513,358). Next, we evaluated the clinical and pathologic characteristics of HCV- or HBV-infected NHL cases. Non-Hodgkin's lymphoma was classified according to the Working Formulation classification.

RESULTS

Thirty-seven cases (14.9%) were found to be infected with HCV or HBV; of these, 20 (8.1%) were infected with HCV, and 17 (6.9%) with HBV. In male NHL patients, the rate of HCV infection was significantly higher than in an age- and sex-matched population in the same area (P < 0.001, Mantel-Haenszel test). The rate of HBV infection also tended to be higher in the population (P = 0.0551). In contrast, in female NHL patients, the rate of HCV or HBV infection was not higher than in the general population. In HCV-infected cases, 15 cases (75%) had B-cell NHL and 16 cases (80%) were classified as being in the intermediate grade; B-cell NHL comprised 83% of all NHL cases. In HBV-infected NHL cases, 11 (65%) were of B-cell type and 10 (58%) were classified as being in the intermediate grade.

CONCLUSIONS

The high prevalence of HCV or HBV infections in our study population provides epidemiologic evidence suggesting that HCV and HBV infections may be involved in the development of a subgroup of NHL in males. Our investigation also revealed that both HCV- and HBV-infected NHL patients showed certain similarities in clinical and pathologic manifestations.

X-ray diffraction evidence for the lack of stereospecific protein interactions in highly activated actomyosin complex

The structure of actomyosin complex while hydrolyzing ATP was investigated by recording X-ray diffraction patterns from rabbit skeletal muscle fibers, in which exogenously introduced rabbit skeletal subfragment-1 (S1) was covalently cross-linked to the endogenous actin filaments in rigor by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Approximately two-thirds of the introduced S1 was cross-linked. The cross-linking procedure did not affect the profile of the S1-induced enhancement of the actin-based layer line reflections in rigor, indicating that the acto-S1 interactions remained highly stereospecific. In the presence of ATP, the MgATPase of the S1 was highly activated regardless of calcium levels, presumably because the availability of the stereospecific binding sites for both proteins was maximized by the cross-linking. However, the diffraction pattern in the presence of ATP was striking in that the intensity profile of the strong 1/5.9 nm(-1) layer lines was indistinguishable from that from bare actin filaments, despite the fact that the majority of the S1 was still associated with actin. The change of the intensity profiles upon addition of ATP was completely reversible. Model calculations showed that this result can be explained if the S1 is not only swinging around its pivoting point, but the pivoting point itself is also moving on the actin surface in a range of a few nanometers. The results suggest that the stereospecific binding sites, which have been considered important for actomyosin cycling, are paradoxically left unoccupied for most of the time in this highly activated actomyosin complex.

Kinetics of the hepatitis C virus during interferon therapy as a marker of therapeutic response

BACKGROUND

The viral load and subtype of hepatitis C virus (HCV) are predictors of the efficacy of interferon (IFN) therapy. The kinetics of HCV during IFN therapy have been described recently, suggesting that HCV infection is highly dynamic. These observations have raised the issue as to whether early monitoring of the viral load can help guide IFN therapy.

METHODS

We measured HCV-RNA levels at 0, 24 and 48 h after the start of IFN-alpha treatment (10 MU daily for 2 weeks and then three times weekly for 22 weeks) or IFN-beta treatment (6 MU daily for 6 weeks). Then we analyzed the relationship between HCV kinetics and therapeutic response using stepwise multivariate logistic regression analysis.

RESULTS

The exponential decay slope of the viral load during the first 24 h, not the first 48 h or the next 24 h, was a predictor of viral eradication at 6 months after completion of the treatment (sustained response; P = 0.0023). This decay slope was not affected by the HCV serotype or the type of IFN used. Initial viral load and HCV serotype were also predictors, as reported previously (P < 0.0001 and P = 0.0347, respectively). We also proposed a model using a prognostic index that predicted a sustained response with more than 80% sensitivity, specificity and efficacy in an independent and external group of patients.

CONCLUSION

This study demonstrated that the exponential decay slope of the viral load during the first 24 h was an important predictor of the response to IFN therapy as well as the initial viral load and HCV serotype. The model may also be useful for the clinical management of IFN therapy.