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Binge-eating behavior involves rapid consumption of highly palatable foods leading to increased weight gain. Feeding in binge disorders resembles other compulsive behaviors, many of which are responsive to N-acetylcysteine (NAC), which is a cysteine prodrug often used to promote non-vesicular glutamate release by a cystine–glutamate antiporter. To examine the potential for NAC to alter a form of compulsive eating, we examined the impact of NAC on binge eating in a rodent model. Specifically, we monitored consumption of standard chow and a high-fat, high carbohydrate western diet (WD) in a rodent limited-access binge paradigm. Before each session, rats received either a systemic or intraventricular injection of NAC. Both systemic and central administration of NAC resulted in significant reductions of binge eating the WD without decreasing standard chow consumption. The reduction in WD was not attributable to general malaise as NAC did not produce condition taste aversion. These results are consistent with the clinical evidence of NAC to reduce or reverse compulsive behaviors, such as, drug addiction, skin picking and hair pulling.

Acetylcholinesterase (AChE) inhibition is an important research topic because of its wide range of associated health implications. A receptor-specific scoring function was developed herein for predicting binding affinities for human AChE (huAChE) inhibitors. This method entails a statistically trained weighted sum of electrostatic and van der Waals (VDW) interactions between ligands and the receptor residues. Within the 53 ligand training set, a strong correlation was found (R² = 0.89) between computed and experimental inhibition constants. Leave-one-out cross-validation indicated high predictive power (Q² = 0.72), and analysis of a separate 16-compound test set also produced very good correlation with experiment (R² = 0.69). Scoring function analysis has permitted identification and characterization of important ligand−receptor interactions, producing a list of those residues making the most important electrostatic and VDW contributions within the main active site, gorge area, acyl binding pocket, and periferal site. These analyses are consistent with X-ray crystallographic and site-directed mutagenesis studies.

Fibroblast growth factor 2 (FGF‐2) and its receptors (FGFRs) are important regulators of bone cell function. Although FGF‐2 is a major modulator of bone cell function, its expression and regulation in human osteoblasts have not been investigated. We examined FGF‐2 messenger RNA (mRNA) expression and regulation in the human osteosarcoma MG‐63 cells. Northern analysis revealed that MG‐63 cells expressed FGF‐2 mRNA transcripts of 7, 4, 2.2, and 1.3 kilobases (kb). In the absence of serum, treatment with transforming growth factor beta (TGF‐β; 0.1‐10 ng/ml) increased all FGF‐2 mRNA transcripts. Maximal increase was seen with 1 ng/ml of TGF‐β. TGF‐β increased FGF‐2 mRNA expression within 2 h and this was sustained for 24 h. Phorbal myristate acetate (PMA; 1 μM) also increased FGF‐2 mRNA at 6 h. Time course studies showed that TGF‐β did not significantly alter FGFR1 or FGFR2 mRNA expression in MG‐63 cells. Western blotting with anti‐human FGF‐2 revealed that MG‐63 cells synthesize three isoforms of FGF‐2 protein of ∼18, 22/23, and 24 kDa, which were increased after either 6 h or 24 h of treatment with TGF‐β. Increased FGF‐2 mRNA and protein expression in response to TGF‐β was markedly reduced by the protein kinase A (PKA) inhibitor H‐89. Immunogold labeling of MG‐63 cells treated with TGF‐β showed increased labeling for FGF‐2 and FGFR2 in the nuclei. In contrast, TGF‐β treatment significantly decreased FGFR1 labeling in the nuclei. These data show that TGF‐β regulates FGF‐2 gene expression in human osteosarcoma cells. Furthermore, TGF‐β modulates the cellular localization of FGF‐2 and its receptors.

Interleukin-1 (IL-1) and basic fibroblast growth factor (FGF-2) are potent stimulators of osteoclast formation. However, the role of FGF-2 in the responses to IL-1 in bone has not been reported. We examined the effect of IL-1 on FGF-2 mRNA and protein expression in human osteosarcoma MG-63 osteoblasts, normal human osteoblasts (NHOB), and osteoblasts from osteoarthritic patients (F2 and F13). IL-1 increased FGF-2 mRNA expression in osteoblasts within 1.5 to 3 h. MultipleFGF-2 protein isoforms were expressed in human osteoblasts. Twenty-four hours of treatment of MG-63and NHOB cells with IL-1 increased the high-molecular-weight(HMW, 22/24 kDa) and low-molecular-weight (LMW, 18 kDa) FGF-2 proteins intracellularly. In contrast, IL-1 preferentially increased the LMW protein signal intracellularly as well as on the cell surface of F2 and F13 osteoblasts. We conclude that IL-1 is a major stimulator of FGF-2 expression in human osteoblasts. Furthermore, selective increases in the exportable LMW protein in osteoblasts from osteoarthritic patients may be of clinical relevance.

This paper presents a new augmented molecular mechanical potential that incorporates significant quantum mechanical effects for proton and hydride transfer reactions in solution and in enzymes. The solvent is treated explicitly, specified covalent bonds in the solute are allowed to break and form, and the charge distribution of the solute is allowed to vary smoothly from that of the reactant to that of the product during the reaction. Moreover, in order to incorporate changes in bond order and hybridization, an efficient constraint dynamics method is combined with switching functions to smoothly vary the structure of the complex from the reactant to the product structure during the reaction. This new methodology is applied to model nicotinamide adenine dinucleotide (NADH) hydride transfer reactions, in particular to the oxidation of ethanol by the NAD⁺ analog 1-methyl-nicotinamide in acetonitrile and in water. Both cis and trans orientations of the NADH amide sidearm and both protonated and deprotonated forms of the substrate are studied. The structures and charge distributions of the model complexes are obtained from ab initio gas phase geometry optimizations at the Hartree−Fock 6-31G* level and are utilized to parametrize the potential energy surface. Classical free energy curves in both acetonitrile and water are calculated in order to illustrate the solvent effects on the energy gap between the reactant and the product states. The radial distribution functions between the solute and the water molecules together with the orientational distributions of the hydration shell water molecules are also calculated in order to elucidate the nature and extent of hydrogen bonding between the solvent and the solute.