Use of Quantal Method for Estimation of Agricultural Production

The usual analysis of quantal response data occurring in diverse fields such as economics, medicine, psychology and toxicology use probit and logit models or their extensions with generalised least squares or the principle of likelihood as the method of statistical inference. The quantal method was first used for estimation of agricultural production by S. M. Vidwans (1991). He has collected the data on yield rate of rabi jowar from the farmers for year 1981 in four villages in Shirur taluka and three villages in Daund taluka of Pune district of Maharashtra in India. The probit regression line is fitted. The fit is not good. The estimation is done using truncation of data. Here we observed that a second degree polynomial is a good fit to the data. This will give correct prediction of agricultural production with smaller standard error.     

Perceptions of Audio Computer-Assisted Self-Interviewing (ACASI) among Women in an HIV-Positive Prevention Program

Background

Audio Computer-Assisted Self Interviewing (ACASI) has improved the reliability and accuracy of self-reported HIV health and risk behavior data, yet few studies account for how participants experience the data collection process.

Methodology/Principal Findings

This exploratory qualitative analysis aimed to better understand the experience and implications of using ACASI among HIV-positive women participating in sexual risk reduction interventions in Chicago (n = 12) and Philadelphia (n = 18). Strategies of Grounded Theory were used to explore participants'' ACASI experiences.

Conclusion/Significance

Key themes we identified included themes that could be attributed to the ACASI and other methods of data collection (e.g., paper-based self-administered questionnaire or face-to-face interviews). The key themes were usability; privacy and honesty; socially desirable responses and avoiding judgment; and unintentional discomfort resulting from recalling risky behavior using the ACASI. Despite both positive and negative findings about the ACASI experience, we conclude that ACASI is in general an appropriate method for collecting sensitive data about HIV/AIDS risk behaviors among HIV-positive women because it seemed to ensure privacy in the study population allowing for more honest responses, minimize socially desirable responses, and help participants avoid actual or perceived judgment.     

Isolation and immunochemical characterization of neuropeptides from the midgut of the Colorado potato beetleLeptinotarsa decemlineata

The midgut of the Colorado potato beetle showed endocrine cells immunopositive to monoclonals like MAC-18, MAC-3 and polyclonals to FMRF-amide and AKH-241. Extraction and HPLC-fractionation of the midgut extracts after partial purification and characterization showed immunopositive reaction to the monoclonals and also showed myotropic activity stimulating the potato beetle gut. Molecular mass of the two active peptides isolated were 22 and 26 kDa respectively. Both these peptides could be immunocytochemically demonstrated in the brain neurosecretory cells of the red cotton bug,Dysdercus cingulatus and the castor semilooper,Achaea janata as well.     

Oligomers of grape-seed procyanidin extract activate the insulin receptor and key targets of the insulin signaling pathway differently from insulin

Procyanidins are bioactive flavonoid compounds from fruits and vegetables that possess insulinomimetic properties, decreasing hyperglycaemia in streptozotocin-diabetic rats and stimulating glucose uptake in insulin-sensitive cell lines. Here we show that the oligomeric structures of a grape-seed procyanidin extract (GSPE) interact and induce the autophosphorylation of the insulin receptor in order to stimulate the uptake of glucose. However, their activation differs from insulin activation and results in differences in the downstream signaling. Oligomers of GSPE phosphorylate protein kinase B at Thr308 lower than insulin does, according to the lower insulin receptor activation by procyanidins. On the other hand, they phosphorylate Akt at Ser473 to the same extent as insulin. Moreover, we found that procyanidins phosphorylate p44/p42 and p38 MAPKs much more than insulin does. These results provide further insight into the molecular signaling mechanisms used by procyanidins, pointing to Akt and MAPK proteins as key points for GSPE-activated signaling pathways. Moreover, the differences between GSPE and insulin might help us to understand the wide range of biological effects that procyanidins have.     

A plausible explanation for enhanced bioavailability of P-gp substrates in presence of piperine: simulation for next generation of P-gp inhibitors

P-glycoprotein (P-gp) has a major role to play in drug pharmacokinetics and pharmacodynamics, since it effluxes many cytotoxic hydrophobic anticancer drugs from gastrointestinal tract, brain, liver and kidney. Piperine is known to enhance the bioavailability of curcumin, as a substrate of P-gp by at least 2000 %. Besides these at least 50 other substrates and inhibitors of P-gp have been reported so far. All P-gp inhibitors have diverse structures. Although little is known about binding of some flavonoids and steroids at the NBD (nucleotide binding domain) of P-gp in the vicinity of ATP binding site inhibiting its hydrolysis, a valid explanation of how P-gp accommodates such a diverse set of inhibitors is still awaited. In the present study, piperine up to 100 μM has not shown observable cytotoxic effect on MDCK cell line, and it has been shown to accumulate rhodamine by fluorescence microscopy and fluorescent activated cell sorter in MDCK cells. Computational simulation for piperine and some first and second generation P-gp inhibitors has shown that these dock at the NBD site of P-gp. A comparative simulation study has been carried out regarding their docking and binding energies. Binding conformation of P-gp co-crystallized complexes with ADP, AMP-PNP (Adenylyl-imidodiphosphate), and ATP were compared with piperine. The receptor based E-pharmacophore of docked piperine has been simulated to find common features amongst P-gp inhibitors. Finally it has been concluded that piperine could be utilized as base molecule for design and development of safe non-toxic inhibitor of P-gp in order to enhance the bioavailability of most of its substrates.