Therapeutic effects of proanthocyanidins on the pathogenesis of periodontitis--an overview

Periodontitis is a bacterially induced chronic inflammatory disease that destroys the connective tissue and bone that support teeth. Bacteria initiates periodontitis and destruction of the alveolar bone and periodontal connective tissue is clearly observed. But, the events occuring between these two points of time remain obscure and this study focusses on these aspects. The proanthocyanidins (PC) have variable pharmacological and nutraceutical benefits including improvement of ischemic cardiovascular disease, prevention of atherosclerosis and antiarthritic, anticancer and antimicrobial activities. The benefits associated with the antioxidant activity of PC have been evaluated both in vivo and in vitro. But, reports on the ameliorative effects of PC on oral diseases and specifically on periodontitis are very few. Hence, a novel attempt is made to review the possible protective effects of PC and its mechanism of action in periodontitis and also to show whether PC could be developed as a therapeutic agent for periodontitis.     

Fate of Mycobacterium tuberculosis inside rate peritoneal macrophages in vitro

Streptozotocin-induced diabetic rats were maintained on 0.5% curcumin containing diet for 8 weeks. Blood cholesterol was lowered significantly by dietary curcumin in these diabetic animals. Cholesterol decrease was exclusively from LDL-VLDL fraction. Significant decrease in blood triglyceride and phospholipids was also brought about by dietary curcumin in diabetic rats. In a parallel study, wherein diabetic animals were maintained on a high cholesterol diet, the extents of hypercholesterolemia and phospholipidemia were still higher compared to those maintained on control diet. Curcumin exhibited lowering of cholesterol and phospholipid in these animals also. Liver cholesterol, triglyceride and phospholipid contents were elevated under diabetic conditions. Dietary curcumin showed a distinct tendency to counter these changes in lipid fractions of liver. This effect of curcumin was also seen in diabetic animals maintained on high cholesterol diet. Dietary curcumin also showed significant countering of renal cholesterol and triglycerides elevated in diabetic rats.In order to understand the mechanism of hypocholesterolemic action of dietary curcumin, activities of hepatic cholesterol-7a-hydroxylase and HMG CoA reductase were measured. Hepatic cholesterol-7a-hydroxylase activity was markedly higher in curcumin fed diabetic animals suggesting a higher rate of cholesterol catabolism. (Mol Cell Biochem 166: 169-175, 1997)     

Cardiorespiratory effects of diazepam-ketamine, xylazine-ketamine and thiopentone anesthesia in male Wistar rats--a comparative analysis

Several anesthetics are known to cause respiratory and cardiovascular depression in humans and animals; but, these diverse effects have not been extensively investigated in laboratory rodents. The objective of this study is to choose a suitable anesthetic combination for use in surgical models eg. coronary artery ligation in rats. Male Wistar rats were anesthetized with three different drugs viz. diazepam-ketamine (DK) (2.5 mg/Kg, intraperitoneally (i.p); 50 mg/Kg, i.p), xylazine-ketamine (XK) (5 mg/Kg i.p; 50 mg/Kg i.p) and thiopentone (T) (40 mg/Kg i.p) and the respiratory and cardiovascular functions were assessed after coronary artery ligation. Heart rate (HR), mean arterial pressure (MAP), partial pressure of carbon dioxide (PaCO2), partial pressure of oxygen (PaO2), oxygen saturation percentage (O2 sat (%)), arterial blood pH and rectal body temperature were studied in detail. During the anesthetic regime, HR was lower till 60 min in XK and T ligated group (333 +/- 6; 304 +/- 8 beats/min) and it was near normalcy in the case of DK ligated group (394 +/- 6 beats/min). Significant respiratory depression was particularly reflected in the T ligated group with an increase in PaCO2 at 30 min (40.32 +/- 2.64 mmHg), which decreased to 38.2 +/- 2.23 mmHg at 60 min. Throughout the investigation, DK showed the least overall effects compared to XK and T on respiratory functions. Thus, DK could be considered to be a suitable anesthetic for use in a surgical model such as coronary artery ligation in albino rats.     

Immobilization of trypsin on sand: Mode of binding

Acid-washed and heat-treated river sand was separated into different fractions by geochemical methods and immobilization of trypsin was carried out on the separated fractions using 3-aminopropyltriethoxysilane and glutaraldehyde. Scanning Electron Micrographs of the purified fraction (Sp. gr >2.5 and <2.8) of magnetically non-susceptible sand and quartz showed that the enzyme could be fixed on the supports. Malonic acid (16.3 nmol and 16.7nmol per g) appeared to be bound to alkylamine purified fraction of magnetically non-susceptible sand and alkylamine quartz, respectively. Studies on the effect of 6 M guanidine.HCl on immobilized trypsin demonstrated that immobilized trypsin had considerable stability against denaturation. The results obtained indicated that magnetically non-susceptible sand was found to be nearly as good as quartz for trypsin immobilization and that trypsin was covalently coupled to sand via 3-aminopropyltriethoxysilane and glutaraldehyde.     

Influence of isoproterenol-induced myocardial infarction on certain glycohydrolases and cathepsins in rats

The changes in the activities of certain lysosomal hydrolases, viz., beta-glucuronidase, beta-N-acetylglucosaminidase, beta-galactosidase, beta-glucosidase, alpha-glucosidase, alpha-galactosidase, alpha-mannosidase, cathepsin B, cathepsin D, and collagenolytic cathepsin, in serum and heart of rats subject to myocardial infarction with isoproterenol, were studied during the periods of peak infarction and recovery. The activities of all the enzymes assayed exhibited a significant increase both in serum and in heart at peak infarction stage and these levels returned to normal during the stage of recovery and repair. The infiltration of inflammatory cells at the infarct regions and the altered lysosomal fragility are probably responsible for the increased activity of the enzymes studied. This may also bring about the catabolism of connective tissue constituents as reported in literature.     

Alterations in human gingival glycosaminoglycan pattern in inflammation and in phenytoin induced overgrowth

Glycosaminoglycans were extracted from normal, inflamed and phenytoin induced overgrowth of human gingival tissue by proteolysis and alcohol precipitation. Extracts were run in a Dowex-1 column and the fractions were treated with mucopolysaccharidases. Cellulose acetate electrophoresis was carried out with or without enzyme digestion for identification of individual glycosaminoglycans. Glycosaminoglycans were found to be decreased in inflammation but were observed to increase in the overgrowth. Hyaluronic acid was found to be increased in both the pathological conditions. Dermatan sulphate, chondroitin sulphate and heparan sulphate were observed to be decreased in inflammation. In overgrowth, dermatan sulphate and chondroitin sulphate were found to increase while the presence of heparan sulphate was not significant. The changes in the pattern of individual glycosaminoglycan in the two varied conditions are discussed.Abbreviations GAG glycosaminoglycan - MPS mucopolysaccharide - DS dermatan sulphate - HS heparan sulphate - CS chondroitin sulphate - HA hyaluronic acid - KS keratan sulphate     

Strain improvement of Aspergillus niger for enhanced lipase production

The enhancement of lipase production from Aspergillus niger was attempted by ultraviolet (UV) and nitrous acid mutagenesis, and the mutants were selected on media containing bile salts. Nitrous acid mutants exhibited increased efficiency for lipase production when compared with UV mutants in submerged fermentation. The hyperproducing UV and nitrous acid mutants were further subjected to a second step of mutagenesis to devise an economical and ecofriendly technique for lipase production by the effective use of hydrocarbons. One percent kerosene was found to be optimal for lipase production, and one of the mutant strains NAII exhibited 2.53 times more increased lipase activity than the parental strain did. This investigation indicates a possible role for the A. niger mutant strains in the biodegradation of oil-polluted environments for the development of ecofriendly technologies.     

Lipase assay in soils by copper soap colorimetry

A simple and sensitive method for the estimation of lipase activity in soils is reported. In this method, 50 mg of soil is incubated with emulsified substrate, the fatty acids liberated are treated with cupric acetate-pyridine reagent, and the color developed is measured at 715 nm. Use of olive oil in this protocol leads to an estimation of true lipase activity in soils. The problem of released fatty acids getting adsorbed onto the soil colloids is obviated by the use of isooctane, and separate standards for different soils need not be developed. Among the various surfactants used for emulsification, polyvinyl alcohol is found to be the most effective. Incubation time of 20 min, soil concentration of 50 mg, pH 6.5, and incubation temperature of 37 °C were found to be the most suitable conditions for this assay. During the process of enrichment of the soils with oil, interference by the added oil is avoided by the maintenance of a suitable control, wherein 50 mg of soil is added after stopping the reaction. This assay is sensitive and it could be adopted to screen for lipase producers from enriched soils and oil-contaminated soils before resorting to isolation of the microbes by classical screening methods.     

In vivo labeling studies on the biosynthesis and degradation of collagen in experimental myocardial infarction.

The biosynthesis and degradation of myocardial collagen was studied in myocardium infarcted rats after a single intraperitoneal injection of 3H-proline. The incorporation of tritiated proline into collagen as 3H-hydroxyproline was regarded as a measure of collagen synthesis. The total content as well as total activity of hydroxyproline were measured in the whole homogenate, neutral salt soluble fraction, insoluble fraction and in urine collected at different time intervals and specific activities were calculated. Both collagen anabolism and catabolism were found to be affected in infarcted rat hearts. Degradation of existing collagen at the earlier stages of myocardial infarction and a simultaneous new collagen synthesis and deposition as insoluble form later took place.     

Myocardial ischemia and reperfusion injury in rats: lysosomal hydrolases and matrix metalloproteinases mediated cellular damage

The aim of this study was to evaluate the time course events of cellular damage during myocardial ischemia and reperfusion injury in rats and to find out a correlation between the structural alterations with respect to the biochemical changes. Cardiac biomarkers and lysosomal enzymes viz. cathepsin D, acid phosphatase and β-glucuronidase and matrix metalloproteinases (MMPs) were evaluated at different time points, in response to ischemia-reperfusion induced oxidative stress in an isolated rat heart model perfused in Langendorff mode. Microscopically, changes in myocardial architecture, myofibrillar degradation, and collagen (COL) integrity were studied using hematoxylin-eosin, Masson’s trichrome and toluidine blue staining techniques. A three-fold increase in the level of myoglobin was observed after 30 min of ischemia followed by 120 min of reperfusion as compared to 15 min ischemia, 120 min reperfusion. Similarly, a significant increase (P < 0.05) in the levels of lipid peroxides and superoxide anion coupled with a decrease in enzymatic and nonenzymatic antioxidant levels were observed. A concomitant increase in the activity of cathepsin D (24.07 ± 0.95) and a higher expression of MMPs after 120 min of reperfusion following 30 min ischemia were shown to correlate with the myocardial damage as shown by histopathology, suggesting that free radical induced activation of cathepsin D and MMPs could mediate early damage during myocardial ischemia and reperfusion.