Consumption Externalities and Wealth Distribution in a Neoclassical Growth Model

This paper explores the distributional effect of consumption externalities in a neoclassical growth model with heterogeneous agents. The economy consists of two types of agents each of which perceives different degrees of intergroup as well as intragroup consumption external effects. It is shown that the stationary distribution and transitional dynamics are highly sensitive to the specification of preference structures of each type of agents.

Progressive Taxation, Wealth Distribution, and Macroeconomic Stability

Using the standard neoclassical growth model with two types of agents, we examine how the presence of heterogenous agents affects the stabilization role of progressive income taxation. We first show that if the marginal tax payment of each agent increases with her relative income, the steady state satisfies local saddlepoint stability so that the equilibrium is determinate. However, unlike the representative agent models with progressive taxation, our model with heterogeneous agents may have the possibility of equilibrium indeterminacy. The indeterminacy conditions depend not only on the property of tax functions but also on production and preference structures.heterogeneous agents, progressive taxation, wealth distribution, aggregate stability

Consumption Externalities and Equilibrium Dynamics with Heterogenous Agents

This paper explores the effect of consumption externalities on equilibrium dynamics of a standard neoclassical growth model in which there are two types of agents. To emphasize the presence of heterogenous agents, we distinguish intergroup consumption externalities from intragroup consumption externalities. We show that if the intragroup externalities dominates the intrergroup external effects, then the steady state equilibrium satisfies saddle-point stability and the equilibrium path of the economy is uniquely determined. In contrast, if the intergroup external effects of consumption are strong enough, the steady-state equilibrium is either unstable or locally indeterminate. Based on the analytical as well as numerical considerations, we give intuitive implications of stability conditions.Consumption externalities, Equilibrium determinacy, Heterogeneous agents, Progressive taxation

Consumption Externalities and Equilibrium Dynamics with Heterogenous Agents

This paper explores the effect of consumption externalities on equilibrium dynamics of a standard neoclassical growth model in which there are two types of agents. To emphasize the presence of heterogenous agents, we distinguish intergroup consumption externalities from intragroup consumption externalities. We show that if there are intragroup consumption externalities alone, then the steady state equilibrium satisfies saddle-point stability and the equilibrium path of the economy is uniquely determined. In contrast, even if the intragroup consumption externalities do not exist, the intergroup external effects of consumption may yield either unstability or local indeterminacy of the steady-state equilibrium. In addition to analytical considerations, we show the relationship between the stability and the consumption externalities in numerical examples.consumption externalities, heterogeneous agents, progressive taxation, equilibrium determinacy

A Novel Animal Model of Nonalcoholic Steatohepatitis (NASH): Hypoxemia Enhances the Development of NASH

Recent reports described a high incidence of nonalcoholic steatohepatitis (NASH) in patients with obstructive sleep apnea. Accordingly, we hypothesized that recurrent and intermittent hypoxemia plays an important role in the pathogenesis of NASH. Our objective was construction of a practical and accurate experimental model to reproduce the key features of NASH in humans. Chemical hypoxemia through methemoglobinemia was induced by daily intraperitoneal injection of sodium nitrite (40 mg/kg) for 4 weeks in rats with fatty liver. The later was induced by 4-week feeding a choline-deficient high-fat diet (CDHF). Besides, the normal chow diets feeding groups were prepared with in the same manner except for CDHF feeding. The animal experiment was performed in four groups; Normal control, Hypoxemia, CDHF, and CDHF + hypoxemia. Nitrite was given for the later 4 weeks to each rat of Hypoxemia and CDHF + hypoxemia. CDHF + hypoxemia rats were confirmed to develop histological changes that resemble those of patients with NASH, together with biochemical liver dysfunction, while CDHF group was limited in mild steatosis, and Hypoxemia group liver was normal. Present study established a reproducible and useful NASH model resembling the main features of NASH in humans, and showed first that recurrent and intermittent hypoxemia aggravate fatty liver to steatohepatitis and liver fibrosis

Beneficial Effects of Fermented Green Tea Extract in a Rat Model of Non-alcoholic Steatohepatitis

Oxidative stress is frequently considered as a central mechanism of hepatocellular injury in non-alcoholic steatohepatitis (NASH). The aim of this study was to investigate the effects of fermented green tea extracts (FGTE) on NASH. Rats were fed a choline-deficient high-fat diet for 4 weeks to nutritionally generate fatty livers. NASH was induced chemically by oxidative stress using repeated intraperitoneal injections of nitrite. Rats with NASH developed steatohepatitis and liver fibrosis after 6-week of such treatment. At 10 weeks, blood and liver samples were collected from anesthetized animals and assessed for extent of OS injury and effects of FGTE, by biochemical, histological and histochemical analyses. FGTE reduced serum levels of liver enzymes, lipid peroxidation and production of mitochondrial reactive oxygen species. In addition, FGTE showed inhibition of progressions of cirrhosis. Our findings suggest that our FGTE have strong radical scavenging activity and may be beneficial in the prevention of NASH progression

Beneficial effects of Vitis coignetiae Pulliat leaves on nonalcoholic steatohepatitis in a rat model

Vitis coignetiae Pulliat (Yamabudo) is used as a health juice and wine based on the abundant polyphenols and anthocyanins in its fruit. However, it is not known whether the leaves of this plant confer similar benefits. This study investigated the hepatoprotective effects of aqueous extracts from Vitis coignetiae Pulliat leaves (VCPL) in an animal model of nonalcoholic steatohepatitis (NASH). Rats were fed a choline-deficient high-fat diet for four weeks to generate fatty livers. NASH was induced by oxidative stress loading. Ten weeks later, blood and liver samples were collected from anesthetized animals and assessed biochemically, histologically, and histochemically to determine the extent of oxidative stress injury and the overall effects of VCPL. Six-week VCPL extract supplementation reduced serum levels of liver enzymes, decreased CYP2E1 induction, increased plasma antioxidant activities and delayed the progression of liver fibrosis. The findings suggested that VCPL has strong radical-scavenging activity and may be beneficial in preventing NASH progression.</p