Role of fibrillar Abeta25-35 in the inflammation induced rat model with respect to oxidative vulnerability.

The major pathological ramification of Alzheimer's disease (AD) is accumulation of beta-Amyloid (Abeta) peptides in the brain. An emerging therapeutic approach for AD is elimination of excessive Ass peptides and preventing its re-accumulation. Immunization is the most effective strategy in removing preexisting cerebral Abetas and improving the cognitive capacity as shown in transgenic mice model of AD. However, active immunization is associated with adverse effect such as encephalitis with perivascular inflammation and hemorrhage. Details about the mechanistic aspects of propagation of these toxic effects are matter of intense enquiry as this knowledge is essential for the understanding of the AD pathophysiology. The present work aimed to study the oxidative vulnerability in the plasma, liver and brain of the inflammation-induced rats subjected to Ass immunization. Induction of inflammation was performed by subcutaneous injection of 0.5?ml of 2% silver nitrate. Our present result shows that the proinflammatory cytokines such as IL1alpha and TNFalpha are increased significantly in the inflammation-induced, Abeta1-42, Abeta25-35 treated groups and inflammation with Abeta25-35 treated group when compared to control, complete Freund's adjuvant and Abeta35-25 treated groups. These increased proinflammatory cytokines concurrently releases significant amount of free radicals in the astrocytes of respected groups. The present result shows that nitric oxide (NO) level was significantly higher (P<0.001) in plasma, liver and brain of the rat subjected to inflammation, Abeta1-42, Abeta25-35 and inflammation with Abeta25-35 injected groups when compared to control. The increased level of lipid peroxides (LPO) (P<0.001) and decreased antioxidant status (P<0.05) were observed in the plasma, liver and brain of inflammation-induced group when compared to control. Our result shows that significant oxidative vulnerability was observed in the inflammation with Ass treated rats when compared to other groups. Based on our results, we suggest that immunization of AD patients with Ass should be done with caution as the increase in Ass could trigger the brain inflammation in uncontrollable level.

Lethal and sub-lethal effects of chlorination on green mussel Perna viridis in the context of biofouling control in a power plant cooling water system.

Continuous chlorination is a widely followed cooling water treatment practice used in the power industry to combat biofouling. The green mussel Perna viridis is one of the dominant fouling organisms ( > 70%) in the Madras Atomic Power Station. Mortality pattern as well as physiological responses such as oxygen consumption, filtration rate, byssus thread production and faecal matter production of three different size groups of this mussel were studied at different chlorination concentrations. At 0.7 mg l(-1) residual chlorine, 3-4 cm size mussels showed 100% mortality in 553.3 h while 8-9 cm size group mussels died within 588 h. At a relatively high level of residual chlorine (9.1 mg l(-1)), 100% mortality in 3-4 cm and 8-9 cm size groups took 94 and 114 h, respectively. All physiological activities studied showed a progressive reduction as chlorine residuals were increased from 0 to 0.55 mg l(-1). The data indicated that the green mussel can sense a residual chlorine level as low as < 0.15 mg l(-1) and complete valve closure occurs only at 0.55 mg l(-1). The paper also shows that the sub-lethal physiological responses are better indices than lethal responses in planning chlorination strategies.

Influence of temperature on the physiological responses of the bivalve Brachidontes striatulus and its significance in fouling control.

Heat treatment offers an alternative method of fouling control to chlorination in power plants. In order to optimise such a procedure it is important to understand the responses of fouling organisms to elevated water temperatures. In this paper we report results of experiments on the lethal and sub-lethal effects of temperature on the bivalve Brachidontes striatulus which is one of the major foulants in the process seawater heat exchangers of Madras Atomic Power Station located at Kalpakkam, on the east coast of India. The important physiological activities, such as, oxygen consumption, filtration rate, byssus thread production and faecal matter production were studied at temperatures varying from 20 to 38 degrees C. Three different size groups [3-5 mm shell length (group 1), 6-10 mm (group 2), 11-15 mm (group 3)] of B. striatulus were used for the experiments. The results showed physiological activities were maximum at 35 degrees C, minimum at 20 and 38 degrees C. Physiological activities increased with size except for byssus thread production, which did not show any trend. Survival times showed a reduction from 30 h at 39 degrees C to < 1 h at 45 degrees C and were independent of body size.