The peptide hormone ghrelin is the endogenous ligand for the type 1a growth hormone secretagogue receptor (GHS-R1a) and the only currently known circulating appetite stimulant. GHS-R1a antagonism has therefore been proposed as a potential approach for obesity treatment. More recently, ghrelin has been recognized to also play a role in controlling glucose-induced insulin secretion, which suggests another possible benefit for a GHS-R1a antagonist, namely, the role as an insulin secretagogue with potential value for diabetes treatment. In our laboratories, piperidine-substituted quinazolinone derivatives were identified as a new class of small-molecule GHS-R1a antagonists. Starting from an agonist with poor oral bioavailability, optimization led to potent, selective, and orally bioavailable antagonists. In vivo efficacy evaluation of selected compounds revealed suppression of food intake and body weight reduction as well as glucose-lowering effects mediated by glucose-dependent insulin secretion.

Compounds that simultaneously activate the three peroxisome proliferator-activated receptor (PPAR) subtypes alpha, gamma, and delta hold potential to address the adverse metabolic and cardiovascular conditions associated with diabetes and the metabolic syndrome. We recently identified the indanylacetic acid moiety as a well-tunable PPAR agonist head group. Here we report the synthesis and structure-activity relationship (SAR) studies of novel aryl tail group derivatives that led to a new class of potent PPAR pan agonists. While most of the tail group modifications imparted potent PPAR delta agonist activity, improvement of PPAR alpha and gamma activity required the introduction of new heterocyclic substituents that were not known in the PPAR literature. Systematic optimization led to the discovery of 4-thiazolyl-phenyl derivatives with potent PPAR alpha/gamma/delta pan agonistic activity. The lead candidate from this series was found to exhibit excellent ADME properties and superior therapeutic potential compared to known PPAR gamma activating agents by favorably modulating lipid levels in hApoA1 mice and hyperlipidemic hamsters, while normalizing glucose levels in diabetic rodent models.

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We have previously produced a series of antigalactose (anti-Gal) hybridomas and characterized their heavy chain gene usage. Here we have quantified the affinity of these Abs for the α-Gal epitope and characterized their in vitro effects on endothelial cell activation and apoptosis. We report that anti-Gal mAbs derived from Gal−/− mice show a range of affinity for the α-Gal epitope, and that affinity was generally increased as the VH gene usage transitioned from germline sequences to sequences exhibiting somatic maturation. Despite an 85-fold range in affinity, all the anti-Gal mAbs examined induced α-Gal-specific endothelial cell activation, and after prolonged exposure induced endothelial cell apoptosis in a complement-independent manner. Only murine anti-Gal mAbs of the IgM or IgG3 subclass, but not IgG1, were effective at initiating complement-dependent cell lysis. Using a novel rat to mouse xenograft model, we examined the in vivo ability of these mAbs to induce xenograft rejection and characterized the rejection using histology and immunohistochemistry. Infusion of complement-fixing IgG3 mAbs resulted in either hyperacute rejection or acute vascular rejection of the xenograft. Surprisingly, infusion of an equal amount of a high affinity anti-Gal IgG1 mAb, that fixed complement poorly also induced a rapid xenograft rejection, which we have labeled very acute rejection. These studies emphasize the importance of in vivo assays, in addition to in vitro assays, in understanding the role of anti-Gal IgG-mediated tissue injury and xenograft rejection.

The effect of drying temperature (50, 60, 70 and 90C) and sample thickness (0.3, 0.4, 0.6 and 0.8 cm) on characterization of hot air drying of sweet potato slices were investigated. Results indicated that drying took place in the falling rate period. The average values of effective moisture diffusivities of sweet potato slices ranged from 3.66 × 10 −10 to 2.11 × 10 −9 m 2 /s within the given drying temperature range. The average activation energy values were 13.48-16.50 kJ/mol for sample thickness of 0.3-0.8 cm. Twelve thin layer drying models were fitted using experimental drying data. The goodness of fit for models was evaluated using the values of coefficient of determination (R 2 ), root mean square error, chi-square (χ 2 ) and mean relative percent deviation (P). Results showed that fitting accuracy of Hii et al. model was better than other models. PRACTICAL APPLICATIONSSweet potato (Ipomoea batatas L.) is widely grown in many countries. In developing countries, there are many problems related to storage and transport of the raw sweet potatoes. The objective of this study was to investigate the effect of drying temperature and sample thickness conditions on the thin layer drying of sweet potato, and to evaluate a suitable drying model for describing the drying process. In addition, the effective moisture diffusivity and Ea in the drying process of sweet potato slices were calculated.