A Review of the Receptor-Binding Properties of p-Synephrine as Related to Its Pharmacological Effects

Bitter orange (Citrus aurantium) extract and its primary protoalkaloid p-synephrine are used widely in weight loss/weight management and sports performance products. Because of structural similarities, the pharmacological effects of p-synephrine are widely assumed to be similar to those of ephedrine, m-synephrine (phenylephrine), and endogenous amine neurotransmitters as norepinephrine and epinephrine. However, small structural changes result in the receptor binding characteristics of these amines that are markedly different, providing a plausible explanation for the paucity of adverse effects associated with the wide-spread consumption of p-synephrine in the form of dietary supplements as well as in various Citrus foods and juices. This paper summarizes the adrenoreceptor binding characteristics of p-synephrine relative to m-synephrine, norepinephrine, and other amines as related to the observed pharmacological effects

Comparative effects of selected non-caffeinated rehydration sports drinks on short-term performance following moderate dehydration

<p>Abstract</p> <p>Background</p> <p>The effect of moderate dehydration and consequent fluid replenishment on short-duration maximal treadmill performance was studied in eight healthy, fit (VO_2max= 49.7 ± 8.7 mL kg^-1min^-1) males aged 28 ± 7.5 yrs.</p> <p>Methods</p> <p>The study involved a within subject, blinded, crossover, placebo design. Initially, all subjects performed a baseline exercise test using an individualized treadmill protocol structured to induce exhaustion in 7 to 10 min. On each of the three subsequent testing days, the subjects exercised at 70-75% VO_2maxfor 60 min at 29-33°C, resulting in a dehydration weight loss of 1.8-2.1% body weight. After 60 min of rest and recovery at 22 C, subjects performed the same treadmill test to voluntary exhaustion, which resulted in a small reduction in VO_2maxand a decline in treadmill performance by 3% relative to the baseline results. Following another 60 min rest and recovery, subjects ingested the same amount of fluid lost in the form of one of three lemon-flavored, randomly assigned commercial drinks, namely Crystal Light (placebo control), Gatorade^®and Rehydrate Electrolyte Replacement Drink, and then repeated the treadmill test to voluntary exhaustion.</p> <p>Results</p> <p>VO_2maxreturned to baseline levels with Rehydrate, while there was only a slight improvement with Gatorade and Crystal Light. There were no changes in heart rate or ventilation with all three different replacement drinks. Relative to the dehydrated state, a 6.5% decrease in treadmill performance time occurred with Crystal Light, while replenishment with Gatorade, which contains fructose, glucose, sodium and potassium, resulted in a 2.1% decrease. In contrast, treatment with Rehydrate, which comprises fructose, glucose polymer, calcium, magnesium, sodium, potassium, amino acids, thiols and vitamins, resulted in a 7.3% increase in treadmill time relative to that of the dehydrated state.</p> <p>Conclusions</p> <p>The results indicate that constituents other than water, simple transportable monosaccharides and sodium are important for maximal exercise performance and effective recovery associated with endurance exercise-induced dehydration.</p

Asymptotic Sign-Solvability, Multiple Objective Linear Programming, and The Nonsubstitution Theorem

In this paper we investigate the asymptotic stability of dynamic, multiple-objective linear programs. In particular, we show that a generalization of the optimal partition stabilizes for a large class of data functions. This result is based on a new theorem about asymptotic sign-solvable systems. The stability properties of the generalized optimal partition are used to extend a dynamic version of the Nonsubstitution Theorem

Encouraging Creativity and Intellectual Stimulation: An Exercise that Forces Students to Think Outside the Box

This exercise involves a hands-on approach to generating innovation and creativity in the workplace. It is feasible as a follow-up, special-topic activity in intellectual stimulation in full-range or transformational leadership training. Participants are presented with the seemingly impossible task of integrating diverse products or services into a single business plan, forcing them to think outside the box. This exercise features lateral and innovative thinking in a highly interactive session, producing innovative and creative solutions from participants. After successfully completing this exercise, participants will be more confident in their ability to creatively solve many challenges that at first glance seem impossible. The paper provides theoretical background, objectives, complete instructions, processing information, and some suggestions for advancing the concepts

Oxidative Toxicity in Neurodegenerative Diseases: Role of Mitochondrial Dysfunction and Therapeutic Strategies

Besides fluorine, oxygen is the most electronegative element with the highest reduction potential in biological systems. Metabolic pathways in mammalian cells utilize oxygen as the ultimate oxidizing agent to harvest free energy. They are very efficient, but not without risk of generating various oxygen radicals. These cells have good antioxidative defense mechanisms to neutralize these radicals and prevent oxidative stress. However, increased oxidative stress results in oxidative modifications in lipid, protein, and nucleic acids, leading to mitochondrial dysfunction and cell death. Oxidative stress and mitochondrial dysfunction have been implicated in many neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, and stroke-related brain damage. Research has indicated mitochondria play a central role in cell suicide. An increase in oxidative stress causes mitochondrial dysfunction, leading to more production of reactive oxygen species and eventually mitochondrial membrane permeabilization. Once the mitochondria are destabilized, cells are destined to commit suicide. Therefore, antioxidative agents alone are not sufficient to protect neuronal loss in many neurodegenerative diseases. Combinatorial treatment with antioxidative agents could stabilize mitochondria and may be the most suitable strategy to prevent neuronal loss. This review discusses recent work related to oxidative toxicity in the central nervous system and strategies to treat neurodegenerative diseases

Collateral and Debt Maturity Choice. A Signaling Model

This paper derives optimal loan policies under asymmetric information where banks offer loan contracts of long and short duration, backed or unbacked with collateral. The main novelty of the paper is that it analyzes a setting in which high quality firms use collateral as a complementary device along with debt maturity to signal their superiority. The least-cost signaling equilibrium depends on the relative costs of the signaling devices, the difference in firm quality and the proportion of good firms in the market. Model simulations suggest a non-monotonic relationship between firm quality and debt maturity, in which high quality firms have both long-term secured debt and short-term secured or non-secured debt.

Directed biosynthesis of unnatural alkaloids in Dolichothele sphaerica

Using appropriate precursors, the two unnatural alkaloids 4(5)-[N-isocaproylaminomethyl]imidazole and 3-[2-N-isovalerylaminoethyl]pyrazole were produced by Dolichothele sphaerica. The former compound represents an unnatural alkaloid formed by the simultaneous introduction of two unnatural precursors, namely isocaproic acid and 4(5)-aminomethylimidazole. The latter compound represents an aberrant alkaloid formed by the introduction of a precursor of different heterocyclic entity, 3-aminoethylpyrazole.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22364/1/0000811.pd