Induction of allergen-specific IgE and IgG responses by anti-idiotypic antibodies

In order to explore idiotypic, anti-idiotypic, and anti-anti-idiotypic responses to allergens, BALB/c mice were immunized with affinity-purified human idiotypic antibodies directed against a highly purified shrimp allergen. This resulted in the production of anti-idiotypic antibodies which were quantitated by using rabbit idiotypic antibodies raised against the same purified allergen. The mouse anti-idiotypic antibodies recognized shrimp-specific human idiotypic antibodies of the IgE isotype from 18 of 20 individuals, and IgG antibodies from 14 of 20 shrimp-sensitive patients. Immunization of BALB/c mice with affinity-purified, allergen-specific anti-idiotypic antibodies induced anti-allergen IgE and IgG responses in the absence of the allergen. This paper thus presents evidence that anti-idiotypic antibodies raised against allergen-specific idiotypic antibodies may substitute for the original allergen in the induction of allergen-specific idiotypic antibodies. The demonstration of shared idiotopes on IgG and IgE antibodies in the sera of shrimp-sensitive patients supports the use of allergen-specific anti-idiotypic antibodies as surrogate allergens.     

Stimulation of colonic mucosal growth associated with oxidized redox status in rats

Limited data in animal models suggest that colonic mucosa undergoes adaptive growth following massive small bowel resection (SBR). In vitro data suggest that intestinal cell growth is regulated by reactive oxygen species and redox couples [e.g., glutathione (GSH)/glutathione disulfide (GSSG) and cysteine (Cys)/cystine (CySS) redox]. We investigated the effects of SBR and alterations in redox on colonic growth indexes in rats after either small bowel transection (TX) or 80% midjejunoileal resection (RX). Rats were pair fed +/- blockade of endogenous GSH synthesis with buthionine sulfoximine (BSO). Indexes of colonic growth, proliferation, and apoptosis and GSH/GSSG and Cys/CySS redox potentials (E(h)) were determined. RX significantly increased colonic crypt depth, number of cells per crypt, and epithelial cell proliferation [crypt cell bromodeoxyuridine (BrdU) incorporation]. Administration of BSO markedly decreased colonic mucosal GSH, GSSG, and Cys concentrations in both TX and RX groups, with a resultant oxidation of GSH/GSSG and Cys/CySS E(h). BSO did not alter colonic crypt cell apoptosis but significantly increased all colonic mucosal growth indexes (crypt depth, cells/crypt, and BrdU incorporation) in both TX and RX groups in a time- and dose-dependent manner. BSO significantly decreased plasma GSH and GSSG, oxidized GSH/GSSG E(h), and increased plasma Cys and CySS concentrations. Collectively, these data provide in vivo evidence indicating that oxidized colonic mucosal redox status stimulates colonic mucosal growth in rats. The data also suggest that GSH is required to maintain normal colonic and plasma Cys/CySS homeostasis in these animal models.     

Computational analysis of deleterious missense mutations in aspartoacylase that cause Canavan’s disease

In this work, the most detrimental missense mutations of aspartoacylase that cause Canavan??s disease were identified computationally and the substrate binding efficiencies of those missense mutations were analyzed. Out of 30 missense mutations, I-Mutant 2.0, SIFT and PolyPhen programs identified 22 variants that were less stable, deleterious and damaging respectively. Subsequently, modeling of these 22 variants was performed to understand the change in their conformations with respect to the native aspartoacylase by computing their root mean squared deviation (RMSD). Furthermore, the native protein and the 22 mutants were docked with the substrate NAA (N-Acetyl-Aspartic acid) to explain the substrate binding efficiencies of those detrimental missense mutations. Among the 22 mutants, the docking studies identified that 15 mutants caused lower binding affinity for NAA than the native protein. Finally, normal mode analysis determined that the loss of binding affinity of these 15 mutants was caused by altered flexibility in the amino acids that bind to NAA compared with the native protein. Thus, the present study showed that the majority of the substrate-binding amino acids in those 15 mutants displayed loss of flexibility, which could be the theoretical explanation of decreased binding affinity between the mutant aspartoacylases and NAA.     

Efficacy of 20-OH-ecdysone on hepatic key enzymes of carbohydrate metabolism in streptozotocin induced diabetic rats

The aim of the present investigation was to evaluate the anti-diabetic activity of 20-OH-ecdysone on glucose metabolic key enzymes in control and streptozotocin induced diabetic rats. On oral administration of 20-OH-ecdysone at a dose of 5mg/kg body weight per day to diabetic rats for 30 days resulted in a significant decrease in the levels of plasma glucose, glycosylated hemoglobin (HbA1c) and an increase in the levels of insulin and hemoglobin. Administration of 20-OH-ecdysone showed significant increase in the levels of glycolytic enzyme (hexokinase) and hepatic shunt enzyme (glucose-6-phosphate dehydrogenase) whereas significant decrease in the levels of gluconeogenic enzymes (glucose-6-phosphatase and fructose-1,6-bisphosphatase) in diabetic treated rats. Furthermore, protection against body weight loss of diabetic animals also observed. This study indicates that the administration of 20-OH-ecdysone to diabetic rats resulted in alterations in the metabolism of glucose with subsequent reduction in plasma glucose levels. A comparison was made between the action of 20-OH-ecdysone and antidiabetic drug-glibenclamide. The effects produced by the 20-OH-ecdysone were comparable to that of glibenclamide.     

Selective ablation of matrix metalloproteinase-2 exacerbates experimental colitis: contrasting role of gelatinases in the pathogenesis of colitis

The matrix metalloproteinases (MMPs), MMP-2 and MMP-9, share structural and substrate similarities and are up-regulated during human as well as animal models of inflammatory bowel disease. We recently demonstrated that epithelial-derived MMP-9 is an important mediator of inflammation and tissue damage in colitis. In this study, we examined the role of MMP-2 in acute colitis. Colitis was induced using two models, administration of dextran sodium sulfate (DSS) and Salmonella enterica subsp. serovar Typhimurium (S.T.). Bone marrow chimeras were performed using bone marrow cells from wild-type (WT) and MMP-2(-/-) mice. Colitis was evaluated by clinical symptoms, myeloperoxidase assay, and histology. MMP-2 protein expression and activity were up-regulated in WT mice treated with DSS or S.T. MMP-2(-/-) mice were highly susceptible to the development of colitis induced by DSS (or S.T.) compared with WT. During inflammation, MMP-2 expression was increased in epithelial cells as well as in the infiltrating immune cells. Bone marrow chimera demonstrated that mucosa-derived MMP-2 was required for its protective effects toward colitis. Furthermore, we demonstrate that severe colitis in MMP-2(-/-) is not due to a compensatory increase in MMP-9. Finally, we show that MMP-2 regulates epithelial barrier function. In contrast to MMP-9, mucosa-derived MMP-2 may be a critical host factor that is involved in the prevention or cessation of the host response to luminal pathogens or toxins, an important aspect of healing and tissue resolution. Together, our data suggest that a critical balance between the two gelatinases determines the outcome of inflammatory response during acute colitis.     

Restorative Effect of Kalpaamruthaa, an Indigenous Preparation, on Oxidative Damage in Mammary Gland Mitochondrial Fraction in Experimental Mammary Carcinoma

Cancer prevention and treatment using phytochemicals have attracted increased interest. Recent studies have shown that Semecarpus anacardium Linn nut milk extract (SA), a promising antioxidant and anticancer drug, exerts its anticancer effect through reducing or quenching reactive oxygen species under different conditions. The present study examined whether Phyllanthus emblica Linn fruit, rich in vitamin C content synergistically in combination can enhance both the antioxidant and anticancer activity of S. anacardium nut milk extract in 7, 12-dimethyl benz[a]anthracene (DMBA)-induced experimental mammary carcinoma in rat model. Female Sprague Dawley rats of 180 ± 10g were categorized into six groups. Three groups were administered DMBA (25mg/rat, orally) dissolved in olive oil to induce mammary carcinoma. One of these groups received Kalpaamruthaa (KA) (300mg/kg b.wt, orally) and other group received SA (200mg/kg b.wt, orally) for 14 days after 90 days of DMBA induction. A vehicle treated control and drug control groups were also included. The mitochondrial fraction of untreated DMBA-induced mammary gland showed 2.61-fold increase in lipid peroxidation level and abnormal changes in the activities/levels of mitochondrial enzymic (superoxide dismutase, glutathione peroxidase and glutathione reductase) and non-enzymic (glutathione, vitamin C and vitamin E) antioxidants were observed. DMBA treated rats also showed decline in the activities of mitochondrial enzymes such as succinate dehydrogenase, malate dehydrogenase, α-ketoglutarate dehydrogenase and isocitrate dehydrogenase. In contrast, rats treated with Kalpaamruthaa showed normal lipid peroxide level and antioxidant defenses. The results of the present study highlight the improved antioxidant property of KA than sole treatment of S. anacardium nut milk extract.     

Therapeutic Potential of Riboflavin,Niacin and Ascorbic Acid on Carbohydrate Metabolizing Enzymes in Secondary Endometrial Carcinoma Bearing Rats

Curative potential of riboflavin, niacin and ascorbic acid against tamoxifen mediated endometrial carcinoma was established by studies on carbohydrate metabolizing enzymes. The enzymes investigated were glycolytic enzymes namely, hexokinase; aldolase; phosphoglucoisomerase and the gluconeogenic enzymes namely, glucose-6-phosphatase and fructose-1, 6-biphosphatase in endometrial carcinoma bearing rats. A significant increase in glycolytic enzymes and a subsequent decrease in gluconeogenic enzymes were observed in plasma, liver and kidney of endometrial carcinoma animals. The administration of riboflavin (45 mg/kg bw/day), niacin (100 mg/kg bw/day) and ascorbic acid (200 mg/kg bw/day) along with tamoxifen (45 mg/kg bw/day) caused a significant decrease in the activity of glycolytic enzymes and a significant increase in the activities of gluconeogenic enzymes to near normal levels in experimental animals. Our results suggest that riboflavin, niacin and ascorbic acid have potential combination therapy against tamoxifen mediated secondary endometrial carcinoma in experimental rats. However, there were no deleterious side effects observed in combinants alone treated animals.     

Effect of combined treatment of thioperamide with some antiepileptic drugs on methionine-sulfoximine induced convulsions in mice

Methionine-sulfoximine (MSO), a convulsant is known to increase the activity of histamine N-methyl transferase. The effect of a selective H3 receptor agonist R- (alpha) methylhistamine (RAMH) and antagonist (thioperamide, THP) and some antiepileptic drugs (gabapentin and sodium valproate) have been evaluated on MSO-induced convulsions in mice. The effect of THP was also evaluated in combination with these antiepileptic drugs. Sodium valproate (300 mg/kg, po) and gabapentin (400 mg/kg, po) offered protection against MSO-induced convulsions as evidenced by a significant prolongation of latency to abnormal dorsoflexion and complete protection against mortality within 6 h of administration. THP (15 mg/kg, ip) alone and in combination with sub-effective doses of gabapentin (75 mg/kg, po) and sodium valproate (75 mg/kg, po) revealed no significant differences from the control group or either drug alone. Hence, the convulsant action of MSO does not appear to be mediated via histaminergic mechanisms.