Activation of retinoic X receptor and peroxisome proliferator-activated receptor-gamma inhibits nitric oxide and tumor necrosis factor-alpha production in rat Kupffer cells

Activators of peroxisome proliferator-activated receptor gamma (PPAR gamma), which forms a heterodimer with retinoic X receptor (RXR), inhibit the production of certain inflammatory mediators. To clarify the role of the PPAR gamma:RXR signaling pathway in Kupffer cells, we studied the effect of an RXR agonist and PPARgamma agonist on LPS-induced nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) production. An RXR-specific agonist, Ro47-5944, and a PPAR gamma-specific agonist, AD4833 (pioglitazone hydrochloride), each inhibited LPS-induced NO and TNF-alpha production. The combined treatment of Ro47-5944 and AD4833 resulted in enhanced inhibition, and suppressed the mRNA levels of NO and TNF-alpha. PPAR gamma:RXR activation did not affect the level of LPS-induced phosphorylation of c-jun N-terminal kinase and p38 mitogen-activated protein kinase. PPAR gamma:RXR activation also did not affect nuclear factor kappa B (NF-kappa B) nuclear translocation nor NF-kappa B and activator protein 1 (AP-1) activation in the electrophoretic mobility-shift assay. Finally, PPAR gamma:RXR activation suppressed the LPS-induced promoter activity of the NF-kappa B-luciferase reporter gene in RAW 264.7 cells. These data imply that PPARgamma:RXR activation suppresses LPS-induced NO and TNF-alpha production in Kupffer cells, and that this inhibition occurred at the transcriptional level. Although no consensus PPAR gamma:RXR-responsive element in the promoter regions of the inducible isoform of nitric oxide synthase (iNOS) and TNF-alpha genes was found, PPAR gamma:RXR may interfere with NF-kappa B and AP-1 transcriptional activity. Our data also suggest a potential therapeutic approach for moderating hepatic injury such as endotoxin shock in which Kupffer cell activation has been implicated.

Testis developments and puberty in the male Tokara (Japanese native) goat

In male Tokara (Japanese native) goats, testis development and the onset of puberty were studied histologically and observing sexual behaviour. Testes weight increased from 36+/-5.4 (S.E.) g (n=5) at 3 months of age to 126+/-6.3 g (n=6) at 12 months. The degree of the testis development differed among kids at 3 months of age and only one of four had produced spermatozoa in the testis. Large number of spermatozoa were always present in seminiferous tubules and epididymal ducts from 4 months of age. The diameter of seminiferous tubules increased from 133+/-9.9 microm (n=4) at 3 months to 198+/-1.0 microm (n=3) at 6 months with little increase thereafter. Mounting and pelvic thrusts onto a teaser doe started at from 9 to 14 weeks of age. Ejaculated semen contained sperm with good motility for the first time from 17 weeks. The male Tokara goat reaches puberty at around 4 months of age but testis development continues to 12 months.

[Intestinal flora of infants with cow milk hypersensitivity fed on casein-hydrolyzed formula supplemented raffinose]

We studied the intestinal flora of infants with cow milk hypersensitivity fed on casein-hydrolyzed formula (MA-1) and the influence of that supplemented with Raffinose (MA-1[R]). Infants with cow milk hypersensitivity were fed with MA-1 for 2 weeks, after which the formula was changed to MA-1[R]. Fourteen subjects were enrolled in this study and divided into two groups; three who fed with breast or conventional milk in addition to MA-1 or MA-1[R](BM group) and 11 mainly fed with MA-1 or MA-1[R] (TF group). Intestinal flora was investigated at two weeks after MA-1 feeding and at two weeks after MA-1[R] feeding, respectively. Bifidobacterium was detected as the most predominant bacteria in all examples in the BM group, and that count and the ratio in all bacteria remained high even after changing MA-1 to MA-1[R]. On the other hand, bacteria count and ratios of Bifidobacterium in all bacteria were conspicuously low in the TF group as compared with the BM group. And with the change from MA-1 to MA-1[R] in the TF group, the bacterial number and the occupation ratio of Bifidobacterium were increased, and Enterobacteriaceae bacterial count and the occupation ratio were decreased. The change of the intestinal flora with MA-1[R] feeding was mainly caused by the breeding action of Raffinose on bifidobacteria. Further studies are needed from a viewpoint of clinical effectiveness about the influence of normalization of the intestinal flora for the treatment of food hypersensitivity.

Analysis of HBs antigen negative variant of hepatitis B virus: unique substitutions, Glu129 to Asp and Gly145 to Ala in the surface antigen gene

We analyzed the surface gene (S gene) of a hepatitis B virus (HBV) isolate with mutations of envelope protein that rendered it undetectable by both a monoclonal hepatitis B surface antigen (HBsAg) enzyme-linked immunosorbent assay (ELISA) and polyclonal HBsAg radioimmunoassay (RIA). Sequencing of independently cloned products of HBV polymerase chain reaction revealed several point mutations within the S gene. Rare substitution was identified both at positions 129 (glutamine to asparagine) and at position 145 (glycine to alanine) in the 'a' determinant region, which is considered to be within a larger antigenic area known as the major hydrophilic region (MHR). A computer-assisted analysis of protein secondary structure could not find any significant difference between this mutant and wild-type HBsAg. However, the substitution of substitution glycine to alanine at position 129 introduce a putative glycosylation site (Asn-Gly-Thr), which may interfere with the antigenicity of HbsAg. Also, HBV variant with substitution at position 145 (Gly to Ala) has been recently reported to be antigenically altered and to show impaired recognition by polyclonal hepatitis B hyperimmune globulin in vitro. These genetic mutations in the S gene inside MHR may allow to escape detection by standard HBsAg assays.

Reversibility of serum NH3 level in a case of sudden onset and rapidly progressive case of type 2 citrullinemia

A 48-year-old male presented with an acute change in mental status due to a marked elevation of plasma NH3 and was diagnosed with citrullinemia with amino acid analysis of blood. Hemodialysis and hemodiafiltration were performed, but serum chemical analysis did not show any improvement which led us to terminate dialysis following intensive care for 3 days. Surprisingly, NH3 level had decreased by 6 days after admission, coinciding with normalization of the size of the pupils. Since spontaneous remission had never been discussed, we discuss this relatively rare, but clinically significant entity with regard to its acute phase management and its potential reversibility.

Incidence and risk factors for subtypes of cerebral infarction in a general population: the Hisayama study

BACKGROUND AND PURPOSE

We estimated the incidence of first-ever cerebral infarction in regard to its subtypes and analyzed their risk factors separately in a community-based prospective cohort study in Japan.

METHODS

Stroke-free subjects (n=1621) aged >/=40 years were followed up for 32 years from 1961. During this period, 298 cerebral infarctions occurred and were divided into 167 lacunar, 62 atherothrombotic, 56 cardioembolic, and 13 undetermined subtypes of infarction on the basis of clinical information including brain imaging and autopsy findings.

RESULTS

The age-adjusted incidence of lacunar infarction (3.8 per 1000 person-years for men and 2.0 for women) was higher than that of atherothrombotic infarction (1.2, 0. 7) and cardioembolic infarction (1.3, 0.5) in both sexes. Time-dependent Cox's proportional hazard analysis revealed systolic blood pressure as well as age to be independent risk factors for all subtypes of cerebral infarction except for cardioembolic infarction in men. Additionally, ST depression on ECG, glucose intolerance, and smoking in men and left ventricular hypertrophy on ECG and body mass index in women remained significant risk factors for lacunar infarction. ST depression was also significantly related to events of atherothrombotic infarction in women. The risk of atrial fibrillation for cardioembolic infarction was outstandingly high in both sexes, and left ventricular hypertrophy and lower total cholesterol were additional risk factors for cardioembolic infarction in women.

CONCLUSIONS

In this Japanese population, lacunar infarction was the most common subtype of cerebral infarction and had a greater variety of risk factors, including not only hypertension but also ECG abnormalities, diabetes, obesity, and smoking, than did atherothrombotic infarction or cardioembolic infarction.

Selenoorganic compound, ebselen, inhibits nitric oxide and tumor necrosis factor-alpha production by the modulation of jun-N-terminal kinase and the NF-kappab signaling pathway in rat Kupffer cells

In response to the bacterial endotoxin, LPS, Kupffer cells are induced to express NO and TNF-alpha. These compounds are involved in hepatic inflammation/injury, especially that associated with endotoxic shock. In this study, we demonstrate that ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]one), a selenoorganic compound, blocks LPS-induced NO and TNF-alpha production by cultured rat liver Kupffer cells. LPS can activate both the NF-kappaB signaling pathway and MAPK signal transduction pathways such as JNK and p38 MAPK. We find that ebselen inhibits LPS-induced NF-kappaB nuclear translocalization, and also suppresses the LPS-induced phosphorylation of JNK, but not the phosphorylation of p38 MAPK. This inhibition of signal transduction leads to a decrease in the transcription of TNF-alpha and the inducible isoform of NO. Furthermore, ebselen inhibits LPS-induced COX-2 expression, which is responsible for proinflammatory prostaglandin production, without affecting constitutive COX-1 expression. These data suggest the mechanism by which ebselen acts as an antiinflammatory agent, and also suggest that ebselen may be potent in preventing hepatic injury such as endotoxic shock, in which Kupffer cell activation has been implicated.

Long-term enalapril therapy in patients with chronic renal failure on a low-protein diet. A prospective randomized comparison with metoprolol

The effect of enalapril (5-10 mg/day) on the progression of chronic renal failure (CRF) was compared with that of metoprolol (40-120 mg/day) in 28 patients for 24 months in a prospective study. Throughout the study, there was no significant difference between the 2 groups in protein intake and urinary sodium excretion. But there was a significant difference between the 2 groups in diastolic and mean arterial blood pressure at 6 months. In the serum creatinine level, there was a significant difference between the 2 groups at 6, 12, 18, and 24 months. In creatinine clearance, there was a significant difference between the 2 groups at 24 months. In addition, the progression of CRF was significantly faster in the metoprolol group than the enalapril group as estimated from the slope of creatinine clearance (p < 0.05) and the slope of glomerular filtration rate (p < 0.0005). In urinary protein excretion, there was a significant difference between the 2 groups at 6 and 18 months (p < 0.05). These findings indicate that enalapril has a suppressive effect on the progression of CRF and also has an antiproteinuric effect by a mechanism independent of its antihypertensive effect.

Beta-lipoproteins influence the serum level of hepatitis C virus

Low density lipoprotein receptor (LDLR) has been proposed as a candidate receptor for hepatitis C virus (HCV). According to previous reports, free beta-lipoproteins in a human serum may regulate the rate of hepatocyte infection by competing with the virus. Therefore, serum HCV levels should be regulated by the rise and fall of serum beta-lipoproteins since the infection rate of virions influences HCV replication in hepatocytes and release of virions by hepatocytes. In this study, we examined the relationship between serum beta-lipoproteins and HCV-antigen (Ag) levels in patients with chronic type C hepatitis. Patients were selected based on strict criteria to eliminate other factors that might influence serum HCV levels. Serum concentrations of beta-lipoproteins and HCV-Ag were measured two or more times within 3 months for each patient. The result showed that HCV-Ag levels were negatively correlated with the increased beta-lipoproteins. The results support the concept that LDLR is a HCV receptor and that beta-lipoproteins competitively inhibit the infection of hepatocytes with HCV through the LDLR.

Impact of Helicobacter pylori infection on gastric cancer incidence in a general Japanese population: the Hisayama study

BACKGROUND

Several nested case-control studies have reported the potentially causal relationship between Helicobacter pylori infection and the development of gastric cancer. However, there has been no prospective study evaluating this issue. The purpose of this study is to examine the impact of H pylori infection on gastric cancer occurrence in a general Japanese population (Hisayama, Japan) stratified according to sex, using a prospective study design.

METHODS

A total of 2602 subjects aged 40 years or older (1070 men; mean age, 57 years; 1532 women; mean age, 59 years) without a history of gastrectomy or gastric cancer were classified according to the status of the serum IgG antibodies to H pylori and observed prospectively for 9 years from 1988.

RESULTS

Infection of H pylori was more common in men (71.5%) than in women (62.5%; P<.001). The age-adjusted incidence of gastric cancer for men (5.3 per 1000 person-years) was 4-fold higher than that for women (1.3; P<.001). In men, the age-adjusted incidence of gastric cancer was significantly higher in the subjects with H pylori infection than in those without it (6.2 vs 2.5; relative risk, 2.59 [95% confidence interval, 1.03-6.50]), whereas no significant difference was observed in women (1.2 vs 1.1; relative risk, 0.99 [95% confidence interval, 0.36-2.68]). These results were similar even after controlling for other risk factors in multivariate analysis. It was estimated that 40.1% of gastric cancers for men in this cohort were attributable to H pylori infection.

CONCLUSION

A significant relationship exists between infection with H pylori and subsequent occurrence of gastric cancer for men but not for women in this Japanese population.

Inactivation of the inhA-encoded fatty acid synthase II (FASII) enoyl-acyl carrier protein reductase induces accumulation of the FASI end products and cell lysis of Mycobacterium smegmatis

The mechanism of action of isoniazid (INH), a first-line antituberculosis drug, is complex, as mutations in at least five different genes (katG, inhA, ahpC, kasA, and ndh) have been found to correlate with isoniazid resistance. Despite this complexity, a preponderance of evidence implicates inhA, which codes for an enoyl-acyl carrier protein reductase of the fatty acid synthase II (FASII), as the primary target of INH. However, INH treatment of Mycobacterium tuberculosis causes the accumulation of hexacosanoic acid (C(26:0)), a result unexpected for the blocking of an enoyl-reductase. To test whether inactivation of InhA is identical to INH treatment of mycobacteria, we isolated a temperature-sensitive mutation in the inhA gene of Mycobacterium smegmatis that rendered InhA inactive at 42 degrees C. Thermal inactivation of InhA in M. smegmatis resulted in the inhibition of mycolic acid biosynthesis, a decrease in hexadecanoic acid (C(16:0)) and a concomitant increase of tetracosanoic acid (C(24:0)) in a manner equivalent to that seen in INH-treated cells. Similarly, INH treatment of Mycobacterium bovis BCG caused an inhibition of mycolic acid biosynthesis, a decrease in C(16:0), and a concomitant accumulation of C(26:0). Moreover, the InhA-inactivated cells, like INH-treated cells, underwent a drastic morphological change, leading to cell lysis. These data show that InhA inactivation, alone, is sufficient to induce the accumulation of saturated fatty acids, cell wall alterations, and cell lysis and are consistent with InhA being a primary target of INH.

Influence of ionic strength on the actomyosin reaction steps in contracting skeletal muscle fibers

Muscle contraction occurs as the result of actin-myosin interaction, which is mediated by the intermolecular forces exerted at the actin-myosin interface. To obtain information about the nature of these intermolecular forces, we tested the sensitivity of various contractile parameters of skinned skeletal muscle fibers to ionic strength (IS) at 3-5 degrees C; IS variation is a useful technique for distinguishing between ionic and nonionic (primarily hydrophobic) types of intermolecular forces. The most striking effect of elevated IS was the strong suppression of isometric tension. However, none of the measured parameters suggested a corresponding decrease in the number of force-generating myosin heads on actin. The rate of actin-myosin association seemed to be only modestly IS-sensitive. The following force-generating isomerization was apparently IS-insensitive. The dissociation of the force-generating actomyosin complex was decelerated by elevated IS, contrary to the expectation from the suppressed isometric tension. These results led us to conclude that an IS-sensitive step, responsible for the large suppression of tension, occurs after force-generating isomerization but before dissociation. The present study suggests that the actomyosin interaction is generally nonionic in nature, but there are at least two ionic processes, one at the beginning and the other close to the end of the actomyosin interaction.

[1,2-Diphenyl-N,N′-bis(salicylidene)-(RR,SS)-1,2-ethanediyldiaminato]nitridomanganese(V)

The title compound, [MnN(C(28)H(22)N(2)O(2))], has a distorted square-pyramidal coordination with an Mn[triple-bond]N bond length of 1.516 (2) A at the apical position. The five-membered chelate ring adopts a gauche conformation with the two phenyl groups in equatorial orientations.

A p160ROCK-specific inhibitor, Y-27632, attenuates rat hepatic stellate cell growth

BACKGROUND/AIMS

p160ROCK, a serine/threonine protein kinase, is a direct RhoA target mediating RhoA-induced assembly of focal adhesions and stress fibers. Recently, Rho signaling pathways were reported to play an important role in the activation of rat hepatic stellate cells (HSC). The aim of this study was to investigate the mechanism of action of a p160ROCK-specific inhibitor, Y-27632, on cultured rat HSC.

METHODS

HSC were isolated from normal rat livers and cultured on fibronectin-coated dishes. The cell morphology and actin cytoskeleton were studied with phase contrast and fluorescence microscopy, respectively. Immunoblot analysis was used to examine phosphorylation of focal adhesion kinase and extracellular signal-regulated kinase, and the expression of cell cycle-associated proteins. HSC proliferation was measured by quantitating the percentage of cells that exhibited nuclear incorporation of 5-bromodeoxyuridine. Type I collagen gene expression and accumulation in HSC culture media were evaluated by Northern blot and enzyme-linked immunosorbent assay, respectively.

RESULTS

Y-27632 consistently blocked cell spreading and suppressed RhoA-induced formation of stress fibers in HSC. In addition, Y-27632 inhibited phosphorylation of focal adhesion kinase and extracellular signal-regulated kinase. Cells treated with Y-27632 failed to proliferate, in contrast to untreated spread cells. This shape-dependent block in cell proliferation correlated with a failure to increase cyclin D1 protein level and to down-regulate the cell cycle inhibitor p27. Y-27632 decreased type I collagen gene expression and accumulation in HSC culture media.

CONCLUSIONS

Our findings indicate that p160ROCK-mediated actin stress fiber assembly is involved in the pathophysiology of hepatic fibrogenesis and suggest that inhibitors of the RhoA-ROCK pathway might be useful therapeutically in liver fibrogenesis.

Synthesis and resorption of a humoral chymotrypsin inhibitor, CI-8, by fat body of the silkworm, Bombyx mori

The Bombyx mori hemolymph contains up to 16 chymotrypsin inhibitors (CIs). The present in vitro culture of tissues in Grace's medium indicated that CI-8, which belongs to the largest molecular-size group of CIs with sugar moiety, is synthesized in the fat body and secreted from it during the feeding period. When the fat body from other strain which synthesizes an allelic component (CI-7) instead of CI-8 was incubated in vitro in hemolymph from the strain which has CI-8, the fat body was found to receive CI-8. Thus it was concluded that CI-8, once secreted into the hemolymph, was again sequestered into the fat body after the onset of spinning. Protein granules isolated from the pupal fat body were shown to contain CI-8, indicating that the sequestered CI-8 is present in the protein granules.

Platelet-derived growth factor receptor tyrosine kinase inhibitor AG1295 attenuates rat hepatic stellate cell growth

Enhanced activity of receptor tyrosine kinases such as the platelet-derived growth factor-receptorbeta (PDGF-Rbeta) has been implicated as a contributing factor in the development of hepatic fibrosis. In this study we have used tyrosine kinase inhibitors of the tyrphostin class (AG1295) to specifically block autophosphorylation of PDGF-Rbeta and proliferation of rat hepatic stellate cells. We also examined the effect of AG1295 on the PDGF-BB-induced activation of the 44 kd and 42 kd mitogen-activated protein (MAP) kinase isoforms (p44mapk/p42mapk). Rat hepatic stellate cells were treated with AG1295 (10 micromol/L) for 24 hours and stimulated with PDGF-BB for 5 minutes. AG1295 specifically inhibited autophosphorylation of PDGF-Rbeta and caused a 20% decrease in PDGF-BB-stimulated bromodeoxyuridine incorporation by rat hepatic stellate cells. Treatment of rat hepatic stellate cells with AG1295 resulted in an inhibition of the PDGF-BB-induced activation of MAP kinase isoforms. Quantification of the immunoprecipitated tyrosine-phosphorylated phosphatidylinositol 3-kinase, phospholipase C-gamma, and p21ras guanosine triphosphatase-activating protein by Western blotting revealed that AG1295 treatment effectively inhibits tyrosine phosphorylation of these kinases in hepatic stellate cells. Our findings demonstrate that AG1295 is a selective inhibitor of the tyrosine phosphorylation of PDGF-Rbeta and its downstream signaling pathway, and this compound could offer a strategy for the treatment of fibrotic liver diseases.

Experimental immune-mediated blepharoconjunctivitis in rats induced by immunization with ragweed pollen

BACKGROUND

A study was performed to compare the effects of immunization with ragweed pollen (RW) in two different adjuvants on the characteristics of a previously described model of experimental immune-mediated blepharoconjunctivitis (EC) in rats.

METHODS

Lewis or Brown Norway (BN) rats were immunized with 100 microg of RW in emulsion with aluminum hydroxide [Al(OH)3] or complete Freund's adjuvant (CFA). Three weeks later, the animals were challenged with eye drops containing RW in PBS. Twenty-four hours after topical challenge, eyes, blood, and lymph nodes were obtained for histology, measurement of antigen-specific antibodies, and proliferation or cytokine assays, respectively. In addition to active immunization, recipients of RW-primed lymph node cells were challenged and evaluated as above.

RESULTS

RW in both adjuvants induced infiltration with predominantly mononuclear cells in Lewis rats and eosinophils in BN rats. As well as active immunization, eosinophils were detected only in BN rats by adoptive transfer of cells. Lymphocyte proliferative responses to RW were high in immunized Lewis rats when CFA was used as an adjuvant. In contrast, proliferative responses in BN rats were higher when Al(OH)3 was used. RW-specific IgE was detected only in BN rats. There were no significant differences in RW-specific IgG1/IgG2a ratio among the four groups. Lewis rats had higher level of RW-specific interferon-gamma in the culture supernatant.

CONCLUSIONS

The characteristics of EC are different in Lewis and BN rats, dependent on the genetic background of the rat strains. The response to RW was similar to other previously used antigens, such as ovalbumin.

Time-resolved two-dimensional X-ray diffraction study of the effect of shortening on activation of contracting skeletal muscle

In twitch contractions of frog skeletal muscle, the isometric tension peaks when intracellular calcium has fallen to near-resting levels. To understand the mechanism of this delayed tension maintenance in the context of calcium regulation, the time course of the tropomyosin movement on actin was monitored by recording the intensity of the 2nd actin layer lines in a time-resolved two-dimensional X-ray diffraction study. The intensity rose ahead of tension, reflecting the tropomyosin movement from its "off" to "on" positions, but it fell with a time course similar to that of tension. Muscle shortening applied at the tension peak was followed by a poor recovery of tension, and accelerated the fall of the reflection intensity. The results suggest that the force-generating myosin heads retain the tropomyosin in its "on" position after the fall of intracellular calcium, and their shortening-induced detachment makes the tropomyosin return to its "off" position, thereby preventing myosin reattachment to actin.