Application of Box-Behnken Design for the Optimized Production of Lactic Acid by Newly Isolated Lactobacillus plantarum JX183220 Using Cassava (Manihot esculenta Crantz) Flour.

Aim: The present study aimed at optimization of Lactic acid production using new isolate, Lactobacillus plantarum JX183220 with cassava flour (Manihot esculenta Crantz) in semi-solid fermentation by Response Surface Methodology. Study Design: Box-Behnken design of Response Surface Methodology was used. Place: Department of Chemical Engineering and Biotechnology, ANITS, Visakhapatnam. Materials and Methods: Lactobacillus plantarum JX183220 isolated from goat milk was used for the production of Lactic acid using cassava flour (CF) in semi-solid fermentation. Different fermentation parameters such as incubation time, inoculum volume, pH, temperature, substrate concentration (cassava flour), and Calcium carbonate concentration were initially optimized in preliminary studies. The substrate concentration, temperature and pH were chosen as potential variables and further optimized using Box-Behnken design of Response Surface Methodology. A second order polynomial regression model was fitted and was found adequate with a high coefficient of determination, R2 (0.9913). Validation experiment was carried out at optimum conditions of the parameters as determined from the model. Results: The preliminary experiments revealed that maximum production of lactic acid by Lactobacillus plantarum JX183220 was observed on 4th day of incubation with 2% inoculum and 0.3% Calcium carbonate. Optimization using Box -Behnken design of RSM resulted in maximum Lactic acid production of 18.3679 g/100 g of cassava at optimum conditions of substrate concentration, 1.225%; Temperature, 36.39°C and pH 6.43. These results were confirmed by validation experiment. Conclusion: Optimum parameters for the direct conversion of cassava flour starch to Lactic acid by new isolate, Lactobacillus plantarum JX183220 were determined. Box Behnken design of RSM was found to be convenient tool with 15 runs for optimizing lactic acid production. The lactic acid production could be further enhanced by saccharification and fermentation in future studies.

Physiology and function of platelets from patients with Alzheimer's disease.

The discovery that intact Alzheimer amyloid precursor protein is present in platelet granules, has created a great interest in the biochemistry, physiology and function of platelets of patients with Alzheimer disease (AD). In this study we monitored various biochemical and physiological parameters, such as serotonin and adenine nucleotide levels, membrane fluidity, agonist-mediated release of arachidonic acid, thromboxane formation, calcium mobilization, as well as irreversible aggregation and secretion of granule contents. Platelets of patients with AD responded poorly when stirred with weak or potent agonists on a platelet aggregometer. Although capable of agonist-mediated calcium mobilization and synthesis of thromboxanes, the aggregation response of platelets of patients with AD to thrombin and archidonate was considerably compromised. In view of the normal biochemistry and signal transduction capabilities, the compromised response of these cells to potent agonists like thrombin suggested an extrinsic defect. The present study has shown that a plasmatic factor is at least in part responsible for the functional abnormalities of AD platelets.

Pharmacology of platelet activation-inhibitory drugs.

The role of blood platelets in the pathogenesis of atherosclerosis, thrombosis, thromboembolism and stroke (hemorrhagic/thrombotic) is well established. In view of this recognized role played by platelets in the complications associated with coronary artery disease and cerebrovascular disease, there is considerable interest in the pharmacology of platelet activation inhibitory drugs. These drugs exert their effect by blocking several different activation signalling mechanisms. Some of the known compounds that modulate platelet function include: inhibitors of arachidonic acid metabolism (nonsteroidal anti-inflammatory drugs and thromboxane synthetase inhibitors), drugs that alter membrane phospholipid composition (omega 3 fatty acids), stimulators of adenylyl cyclase and guanylyl cyclase (PGE1, PGI2, PGD2/ERRF [nitric oxide], nitroglycerin, nitroprusside), phosphodiesterase inhibitors (dipyridamole and methylxanthines) and calcium antagonists (verapamil, nifedipine, diltiazem). Current research on the pharmacology of platelet activation inhibitory drugs is focused on the development of specific receptor antagonists (antibodies, peptides, receptor antagonists). Since platelets have multiple mechanisms for achieving activation, and the process of thrombosis involves multicellular modulation of platelet activity, it will be rather difficult to develop a compound that is capable of causing complete inhibition of activation mechanisms. Therefore, future research will be devoted to development of designer drugs that will be used for preventing discrete platelet responses. This approach may be useful as total inhibition of platelet activation, although it may prevent thrombotic events, may possibly precipitate hemorrhagic conditions. A better understanding of cell signalling pathways and the mechanisms involved in the pathogenesis of cardiovascular cerebrovascular disease will facilitate the development of efficient antiplatelet drugs.

Physiology of blood platelet activation.

Blood platelets interact with a variety of soluble agonists such as epinephrine and adenosine diphosphate (ADP); many insoluble cell matrix components, including collagen and laminin, and biomaterials used for construction of invasive medical devices. These interactions stimulate specific receptors and glycoprotein-rich domains (integrins and nonintegrin) on the plasma membrane and lead to the activation of intracellular effector enzymes. The majority of regulatory events appear to require free calcium. Ionized calcium is the primary bioregulator, and a variety of biochemical mechanisms modulate the level and availability of free cytosolic calcium. Major enzymes that regulate the free calcium levels via second messengers include phospholipase C, phospholipase A2, and phospholipase D, together with adenylyl and guanylyl cyclases. Activation of phospholipase C results in the hydrolysis of phosphatidyl inositol 4,5-bisphosphate and formation of second messengers 1,2-diacylglycerol and inositol 1,4,5-trisphosphate (IP3). Diglyceride induces activation of protein kinase C, whereas IP3 mobilizes calcium from internal membrane stores. Elevation of cytosolic calcium stimulates phospholipase A2 and liberates arachidonic acid. Free arachidonic acid is transformed to a novel metabolite, thromboxane A2, by fatty acid synthetases. Thromboxane A2 is the major metabolite of this pathway and plays a critical role in platelet recruitment, granule mobilization and secretion. Up-regulation in signalling pathways will increase the risk for clinical complications associated with thromboembolic episodes. Down-regulation of signal transduction mechanisms may precipitate bleeding diathesis or stroke.

Coronary artery disease: an overview of risk factors.

Coronary artery disease (CAD) is an important cause of morbidity and mortality in most industrialized nations, and is gaining in importance as a major disease in developing countries as well. Several risk factors, such as cholesterol, smoking, hypertension, obesity, diabetes, stress and physical activity, have been identified as contributors to the pathogenesis of this disease. Studies done in many countries on South Asian immigrants clearly demonstrate the increased risk for coronary heart disease in this population compared to that of local ethnic groups. Higher prevalence of diabetes, blood pressure, glucose intolerance, insulin resistance, low levels of HDL-cholesterol, high levels of LDL-cholesterol, increased plasma triglycerides and obesity are some of the risk factors identified as contributing to CAD in South Asians. The present report will review briefly the available data on CAD and its pathogenesis with particular emphasis on the problems unique to South Asians.

Aspirin in ischemic heart disease--an overview.

Aspirin is one of the oldest and most commonly used nonprescription drugs in the world. Although commonly it is used for relief from common headache and muscular pain, its use in the prevention and treatment of platelet related complications in cardiovascular diseases (CVD) and cerebrovascular disease (CBVD) is quite controversial. A brief review of the major aspirin trials indicated that a full strength aspirin taken daily had no significant beneficial effect in reducing mortality of patients with CVD/CBVD. However, two major trials (ISIS-2, PHS) in which either low dose aspirin (160 mg) or one aspirin administered every other day, have demonstrated significant reduction in fatal and nonfatal cardiovascular events. Even a dose as low as 1 mg aspirin per day significantly lowers platelet thromboxane synthesis. As a result of these studies, low dose aspirin should be the choice of prophylactic therapy aimed at the inhibition of platelet cyclooxygenase activity. Controlled-release low dose aspirin may favorably reduce platelet thromboxane production and spare vascular prostacyclin synthesis. At least 100 mgs of aspirin per day are essential to completely inhibit steady state thromboxane formation. Low dose aspirin (160 mgs) has been shown to be as effective as the full strength aspirin (325 mgs) in reducing clinical complications related to platelet activation. The antithrombotic effect of aspirin is well established and improved formulations, well thought out therapeutic protocols, customized dosage, appropriate timing of delivery, a better understanding of platelet function and pathophysiology of CUD/CBUD will facilitate maximization of the beneficial effects of aspirin.

Influence of low dose enteric-coated aspirin on platelet function.

Little is known about the effect of low dose, enteric-coated aspirin on human blood platelet function. This study was conducted to evaluate the acute effects of a single daily dose of commercially available enteric-coated aspirin on platelet biochemistry, physiology and function. Blood for these studies was obtained from drug-free volunteer donors prior to ingestion of aspirin or following ingestion, either before breakfast or following lunch. Response of platelets to the action of weak agonists was evaluated. In addition, ability of platelets to convert radiolabeled arachidonic acid to thromboxane was monitored. Results of our studies show that a single daily dose of 50 mg of aspirin taken either before breakfast or after lunch effectively prevented the secondary wave aggregation response, as well as secretion of dense body contents when stimulated by agonists such as epinephrine and ADP. Aspirin ingestion caused a dose-dependent inhibition of platelet cyclooxygenase activity as evidenced by the extent of arachidonic acid converted to thromboxane by platelets exposed to aspirin for different time periods. Based on these observations, it is suggested that low dose aspirin may be very useful and desirable to restrain platelet activity in clinical situations in which increased thromboxane formation may initiate vascular hypertension and platelet hyperactivity.