Temporal trends in arthropod abundances after the transition to organic farming in paddy fields.

Organic farming aims to reduce the effect on the ecosystem and enhance biodiversity in agricultural areas, but the long-term effectiveness of its application is unclear. Assessments have rarely included various taxonomic groups with different ecological and economic roles. In paddy fields with different numbers of years elapsed since the transition from conventional to organic farming, we investigated changes in the abundance of insect pests, generalist predators, and species of conservation concern. The abundance of various arthropods exhibited diverse trends with respect to years elapsed since the transition to organic farming. Larval lepidopterans, Tetragnatha spiders, and some planthoppers and stink bugs showed non-linear increases over time, eventually reaching saturation, such as the abundance increasing for several years and then becoming stable after 10 years. This pattern can be explained by the effects of residual pesticides, the lag time of soil mineralization, and dispersal limitation. A damselfly (Ischnura asiatica) did not show a particular trend over time, probably due to its rapid immigration from source habitats. Unexpectedly, both planthoppers and some leafhoppers exhibited gradual decreases over time. As their abundances were negatively related to the abundance of Tetragnatha spiders, increased predation by natural enemies might gradually decrease these insect populations. These results suggest that the consideration of time-dependent responses of organisms is essential for the evaluation of the costs and benefits of organic farming, and such evaluations could provide a basis for guidelines regarding the length of time for organic farming to restore biodiversity or the economic subsidy needed to compensate for pest damage.

Salbutamol inhibits lipopolysaccharide-induced inflammatory responses in rat peritoneal macrophages.

Acute and chronic inflammatory diseases are associated with the induction of inducible nitric oxide synthase (iNOS) and inducible heme oxygenase (HO-1). These inducible enzymes are up-regulated in macrophages subjected to inflammatory stimuli and oxidative stress. beta(2)-Adrenoceptor (AR) agonists, which function as bronchial dilators, are widely used for the treatment of asthma and chronic obstructive pulmonary disease (COPD). We examined whether salbutamol, a classical beta(2)-AR agonist, inhibits the induction of proinflammatory cytokines and stress inducible proteins. Rat macrophages obtained from the abdominal cavity were incubated with lipopolysaccharide (LPS) with or without salbutamol. Induction by LPS of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 was significantly inhibited (P < 0.05) by salbutamol treatment. Induction by LPS of iNOS mRNA and protein was also significantly inhibited (P < 0.05) by salbutamol. LPS-mediated increases in HO-1 mRNA and protein were not appreciably affected by salbutamol. One of the anti-inflammatory mechanisms of salbutamol was thus found to be inhibition of induction by LPS of extracellular stimulus-responsive kinase (ERK) 1/2 in macrophages. These findings suggest that salbutamol has the potential for use as an anti-inflammatory agent due to its suppression of LPS-induced TNF-alpha, and IL-6 and iNOS via ERK pathway without affecting HO-1 expression.

Serum fragmented cytokeratin 18 levels reflect the histologic activity score of nonalcoholic fatty liver disease more accurately than serum alanine aminotransferase levels.

BACKGROUND AND GOALS: Reliable noninvasive biomarkers to assess the histologic activity of nonalcoholic fatty liver disease (NAFLD) have not been established. As the frequency of Mallory bodies is known to be closely associated with the disease severity, we hypothesized that serum levels of Mallory body-related proteins were correlated with NAFLD histologic activity and evaluated this possibility. STUDY: Serum levels of total and fragmented cytokeratin (CK) 18, heat shock protein (Hsp) 70, Hsp90alpha, ubiquitin+1, and p38alpha at the time of liver biopsy were measured in 118 NAFLD patients and their association with histologic findings and NAFLD histologic activity score (NAS) was investigated. RESULTS: Serum levels of both forms of CK18 and Hsp90alpha were markedly higher in patients having nonalcoholic steatohepatitis (NASH) compared with non-NASH ones. Both forms of CK18 significantly correlated with degree of steatosis, lobular inflammation, and ballooning, and showed stronger positive correlations with NAS than serum aspartate and alanine aminotransferase (AST and ALT). Multiple regression analysis further revealed that fragmented CK18 and AST were effective predictors of NAS, with the former being the more definitive of the two (P<0.001 vs. 0.005). In 20 NAFLD patients who received a follow-up biopsy, changes in fragmented CK18 levels, but not AST or ALT levels, closely paralleled those in NAS. CONCLUSIONS: These results establish the usefulness of fragmented CK18 measurement for assessing and monitoring the histologic activity of NAFLD.

Strain differences in hepatic cytochrome P450 1A and 3A expression between Sprague-Dawley and Wistar rats.

Expression of hepatic cytochrome P450 (CYP) isoforms was compared in Sprague-Dawley (SD) and Wistar (WI) rats, which are commonly used strains in preclinical studies. Basal CYP1A1, CYP1A2, and CYP3A2 mRNA levels were higher in WI rats than in SD rats (by 8-, 3- and 2-fold, respectively). Treatment with phenobarbital, a potent CYP inducer, increased the predominance of expression of these three mRNAs in WI rats (by 26-, 4-, and 2-fold, respectively) along with the predominance of increased microsomal total P450 contents and smooth-surface endoplasmic reticulum in the centrilobular hepatocytes. CYP1A enzymatic activity was also higher in WI rats than in SD rats. No strain differences were observed in phenobarbital induction of CYP2B1/2, CYP2C6, or CYP3A1. CYP3A2 mRNA was more strongly induced by dexamethasone, a typical inducer of CYP3A, together with CYP3A1 mRNA, in WI rats than in SD rats (by 2-fold), whereas the CYP1A1 and CYP1A2 mRNA expression induced by beta-naphtoflavone, a typical inducer of CYP1A, did not differ between the two strains. Furthermore, WI rats exhibited predominantly arylhydrocarbon receptor, pregnane X receptor, and constitutive androstane receptor mRNAs, responsible for CYP1A or CYP3A induction, with phenobarbital or dexamethasone induction. In conclusion, significant, predominant expression of hepatic CYP1A and CYP3A mRNAs in WI rats was observed, possibly related to nuclear receptor-mediated induction. Considering the pharmacokinetic and toxicological importance of CYP1A and CYP3A, different outcomes might arise depending on the rat strains used in preclinical studies of drugs metabolized typically or mainly by both isoforms.

Characterization of cytochrome P450 expression in murine embryonic stem cell-derived hepatic tissue system.

An in vitro system for liver organogenesis from murine embryonic stem (ES) cells has been recently established. This system is expected to be applied to the development of a new drug metabolism assay system that uses ES cells as a substitute for animal experiments. The objective of this study was to elucidate the drug metabolism profiles of the murine ES cell-derived hepatic tissue system compared with those of primary cultures of murine adult and fetal hepatocytes. The expression of the genes of the cytochrome P450 (P450) family, such as Cyp2a5, Cyp2b10, Cyp2c29, Cyp2d9, Cyp3a11, and Cyp7a1, was observed in the murine ES cell-derived hepatic tissue system at 16 days and 18 days after plating (A16 and A18). To investigate the activities of these P450 family enzymes in the murine ES cell-derived hepatic tissue system at A16 and A18, testosterone metabolism in this system was analyzed. Testosterone was hydroxylated to 6beta-hydroxytestosterone (6beta-OHT), 16alpha-OHT, 2alpha-OHT, and 2beta-OHT in this system, and was not hydroxylated to 15alpha-OHT, 7alpha-OHT, and 16beta-OHT. This metabolism profile was similar to that of fetal hepatocytes and different from that of adult hepatocytes. Furthermore, pretreatment with phenobarbital resulted in a 2.5- and 2.6-fold increase in the production of 6beta-OHT and 16beta-OHT. Thus, evidence for drug metabolic activities in relation to P450s has been demonstrated in this system. These results in this system would be a stepping stone of the research on the development and differentiation to adult liver.

Tissue- and dose-dependent alteration of stress-inducible proteins by beta2-adrenoceptor agonist, salbutamol, in rats.

The effects of selective beta(2)-adrenoceptor agonists on proinflammatory cytokines and the expression of stress-inducible proteins have not yet been clarified. We investigated the effect of a higher dose (60 mg/kg intravenously) of salbutamol, a selective beta(2)-adrenoceptor agonist, on the induction of interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha in plasma and the expression of protein and mRNA of metallothioein-1 (MT-1), heme oxygenase-1 (HO-1) and inducible nitric oxide synthase (iNOS) in heart, lung, liver and spleen in rats. The plasma IL-6 concentration was significantly increased after administration with a maximum increase at 3 hr in a dose-dependent manner, but IL-1beta and TNF-alpha concentrations were not changed. MT-1 mRNA increased in heart, lung and liver, but not in spleen, and MT-1 protein increased in endocardium, fibroblasts of lung and periportal regions in liver. HO-1 mRNA was not changed in lung, decreased at 3 hr in liver and spleen, and increased at 6 hr in liver. Contrary to liver, HO-1 mRNA in the heart increased at 3 hr and decreased at 6 hr. HO-1 protein increased in cardiomyocytes and centrilobular regions in the liver. iNOS mRNA increased in lung, liver and spleen, but decreased in the heart, and iNOS protein increased in alveolar type II cells and hepatocytes, and decreased in necrotic cardiomyocytes. In contrast, a lower dose (6 mg/kg intravenously) of salbutamol suppressed lipopolysaccharide-induced HO-1 and iNOS mRNA. We conclude that salbutamol tissue- and dose-dependently alters the expression of stress-inducible proteins.

Quantitative estimation of myocardial fibrosis based on receptor occupancy for beta2-adrenergic receptor agonists in rats.

To develop beta2-adrenergic receptor (AR) agonists with higher selectivity, it is essential to evaluate the cardiac side effects which are the most serious side effects of this class of drugs. We studied receptor occupancy of beta1-ARs in rats as a possible cause for the side effect of beta2-AR agonists, namely myocardial fibrosis. Myocardial fibrosis in rats was observed on Day 7 after the administration of salbutamol and terbutaline, both of which are selective beta2-AR agonists, at higher dose levels. To evaluate receptor occupancy, plasma concentrations of (R)-salbutamol and (R)-terbutaline, plasma protein binding and the EC50 for chronotropic effects in rats were determined. Based on the plasma concentrations, the plasma protein binding and EC50, receptor occupancy-time profiles were constructed. The relationship between the receptor occupancy-time profile under the curve, the AUCphi, and the degree of myocardial fibrosis was evaluated with a multiple correlation analysis. Myocardial fibrosis was significantly correlated (r2 > 0.78) to the AUCphi with the threshold above approximately 50%, but not to plasma concentrations. These results indicate that the receptor occupancy theory is also useful for the evaluation of the chronotropic side effects of beta2-AR agonists.