Gel purified LipL32: a prospective antigen for detection of leptospirosis.

BACKGROUND: Leptospirosis, a zoonosis, is a re-emerging disease, affecting populations across the globe. However, the current methods of diagnosis are time- consuming, cumbersome, imprecise or expensive. AIM: To develop an assay for differential and early diagnosis of Leptospirosis. METHODS AND MATERIAL: IgG based ELISA for evaluation of three antigens, namely, a gel-purified recombinant protein (rLipL32), secreted proteins and whole organism sonicates of Leptospira spp. The antigens were evaluated using, rabbit polyclonal antiserum and human sera samples. RESULTS: Studies with a rabbit polyclonal antiserum indicated the utility of these antigens in differentiating Leptospira from other common pathogenic organisms. Evaluation of these antigens with fifteen representative human serum samples indicated gel-purified rLipL32 to be a potentially useful antigen for detection of leptospirosis. The results obtained with IgG ELISA were correlated with the results of microscopic agglutination test (MAT). CONCLUSION: Gel-purified rLipL32 is a valuable antigen for early and accurate diagnosis of leptospirosis. Further evaluation of this assay in field conditions and larger sera samples will indicate its suitability in case of an epidemic.

The combined effects of Trigonella and Allium extracts in the regulation of hyperthyroidism in rats.

The combined effects of Trigonella foenum-graecum and Allium sativum extracts were evaluated for their ameliorative potential in the L-thyroxine-induced hyperthyroidic rat model to contribute to an understanding of interaction between the two extracts. The investigation was carried out using two different doses. A comparison was made with the response of individual plant extracts at the previously studied effective dose in adult Wistar rats rendered hyperthyroidic by daily injections of L-thyroxine (300 microg/kg body wt., s.c.). Propylthiouracil (PTU), an antithyroid drug, was used as a reference compound. Alterations in serum triiodothyronine (T3), thyroxine (T4), glucose, hepatic glucose-6-phosphatase (G-6-Pase) and oxygen consumption were studied as end parameters. Superoxide dismutase (SOD), catalase (CAT) activities, lipid peroxidation (LPO) and reduced glutathione (GSH) were examined to reveal any toxic effects of the drugs. The combined effects of Trigonella and Allium at 200 and 500 mg/kg body wt. respectively, were equipotent as compared to the individual extracts in lowering the serum concentrations of T3 and T4 in hyperthyroidic rats. Our findings reveal that some plant extracts in combination may not always prove to be synergistic. It is therefore suggested that Trigonella foenum-graecum and Allium sativum extracts may be used individually and not together in the regulation of hyperthyroidism.

Achyranthes aspera elevates thyroid hormone levels and decreases hepatic lipid peroxidation in male rats.

A study was made to evaluate the role of Achyranthes aspera on the changes in serum thyroid hormone concentrations and glucose levels in male rats. An attempt was also made to establish the relationship between hepatic lipid peroxidation and extract induced changes in thyroid hormone concentration, if any. Adult male Wistar rats were orally administered with the aqueous leaf extract of Achyranthes aspera at a dose of 200 mg/kg b. wt./day for 7 days. The effects of the extract on body weight, hepatic protein content, lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) activities and on serum triiodothyronine (T3), thyroxine (T4) and glucose levels were evaluated. The extract exhibited significant prothyroidic activity as it enhanced the levels of both the thyroid hormones along with an increase in serum glucose concentration, body weight and hepatic protein content. On the other hand, it decreased hepatic LPO without altering the activities of the two antioxidant enzymes, SOD and CAT significantly, suggesting a direct free radical scavenging activity of the extract. It appears that the Achyranthes aspera leaf extract is both prothyroidic and antiperoxidative in nature.

Role of Moringa oleifera leaf extract in the regulation of thyroid hormone status in adult male and female rats.

The role of Moringa oleifera aqueous leaf extract in the regulation of thyroid hormone status, was studied in adult Swiss rats. Other than the thyroid hormone concentrations, hepatic lipid peroxidation (LPO) and the activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) were evaluated. In the first experiment, effects of the leaf extract (175 mg kg(-1)body wt. day(-1)for 10 days) were studied both in male and female animals. Following the administration of the extract, serum triiodothyronine (T(3)) concentration and hepatic LPO decreased with a concomitant increase in the serum thyroxine (T(4)) concentration, in female rats, while in males no significant changes were observed, suggesting that Moringa oleifera leaf extract is more effective in females than in the males. To evaluate the impact of a higher dose, in the second experiment, the study was repeated in female rats, with 350 mg kg(-1)body wt. day(-1)for the same duration. Almost similar reduction in the serum T(3)concentration (approx. 30%) and an increase in the T(4)concentration were observed suggesting the inhibiting nature of Moringa oleifera leaf extract in the peripheral conversion of T(4)to T(3), the principal source of the generation of latter hormone. As the antiperoxidative effects were exhibited only by the lower dose and percent decrease in T(3)concentration was nearly the same by both the doses, it is suggested that the lower concentration of this plant extract may be used for the regulation of hyperthyriodism. 2000 Academic Press@p$hr

Inhibition of triiodothyronine production by fenugreek seed extract in mice and rats.

The effects of fenugreek seed extract on the alterations in serum thyroid hormone concentrations were studied in adult male mice and rats. Simultaneously, hepatic lipid peroxidation (LPO) and the activities of the antioxidant enzymes, viz superoxide dismutase (SOD) and catalase (CAT) were examined. Administration of methi seed extract (0.11 g kg body wt.(-1) day(-1) for 15 days) to both mice and rats significantly decreases serum triiodothyronine (T(3)) concentration and T(3)/T(4) ratio, but increases thyroxine (T(4)) levels and body weight. While hepatic LPO and CAT activities were not altered, a significant decrease in SOD activity was observed in both the animal models. These findings suggest that fenugreek seed extract induced inhibition in T(4)to T(3) conversion is not peroxidation-mediated and the inhibition in SOD activity could be the result of a decrease in the protein anabolic hormone, T3.

The role of conserved amino acid motifs within the integrin beta3 cytoplasmic domain in triggering focal adhesion kinase phosphorylation.

Integrin-mediated adhesion of cells to extracellular matrix proteins triggers a variety of intracellular signaling pathways including a cascade of tyrosine phosphorylations. In many cell types, the cytoplasmic focal adhesion tyrosine kinase, FAK, appears to be the initial protein that becomes tyrosine-phosphorylated in response to adhesion; however, the molecular mechanisms regulating integrin-triggered FAK phosphorylation are not understood. Previous studies have shown that the integrin beta1, beta3, and beta5 subunit cytoplasmic domains all contain sufficient information to trigger FAK phosphorylation when expressed in single-subunit chimeric receptors connected to an extracellular reporter. In the present study, beta3 cytoplasmic domain deletion and substitution mutants were constructed to identify amino acids within the integrin beta3 cytoplasmic domain that regulate its ability to trigger FAK phosphorylation. Cells transiently expressing chimeric receptors containing these mutant cytoplasmic domains were magnetically sorted and assayed for the tyrosine phosphorylation of FAK. Analysis of these mutants indicated that structural information in both the membrane-proximal and C-terminal segments of the beta3 cytoplasmic domain is important for triggering FAK phosphorylation. In the C-terminal segment of the beta3 cytoplasmic domain, the highly conserved NPXY motif was found to be required for the beta3 cytoplasmic domain to trigger FAK phosphorylation. However, the putative FAK binding domain within the N-terminal segment of the beta3 cytoplasmic domain was found to be neither required nor sufficient for this signaling event. We also demonstrate that the serine 752 to proline mutation, known to cause a variant of Glanzmann's thrombasthenia, inhibits the ability of the beta3 cytoplasmic domain to signal FAK phosphorylation, suggesting that a single mutation in the beta3 cytoplasmic domain can inhibit both "inside-out" and "outside-in" integrin signaling.