The structure-activity relationship between peroxisome proliferator-activated receptor gamma agonism and the antihyperglycemic activity of thiazolidinediones

A new steroidal saponin, aferoside A, has been isolated from the roots of Costus afer. Its structure was established as 3-O-([beta-D-apiofuranosyl-(1-->2)]-[alpha-L-rhamnopyranosyl-(1--> 4)]-beta-D-glucopyranosyl)-25(R)-spirost-5-en-3 beta-ol by chemical transformations and various spectroscopic methods, mainly 2D NMR techniques (COSY, HMQC and HMBC).     

Relation of systemic arterial pulse pressure to coronary atherosclerosis in patients with mitral stenosis

The relation of a wide systemic arterial pulse pressure to coronary atherosclerosis has not been fully defined. One hundred fifty-nine patients > 40 years old with symptomatic mitral stenosis (MS) who received routine coronary angiography were classified into 2 groups according to the presence of > or = 50% diameter narrowing of > or = 1 coronary artery (n = 48) or no significant disease (n = 111). Pulse pressure was determined both by noninvasive sphygmomanometer and invasive catheterization methods. There were no significant differences in risk factors of coronary artery disease (CAD) or the severity of MS between the 2 groups. From multivariate logistic regression analysis, independent predictors of development of CAD in MS were age (standardized coefficient beta = 1.3437, p = 0.0025), gender (beta = 0.0107, p = 0.0105), mean blood pressure (beta = 1.1839, p = 0.0105), and pulse pressure (beta = 1.3157, p = 0.0008). A wide pulse pressure (> or = 60 mm Hg) correlated with the presence of angiographically significant CAD with a sensitivity and specificity of 88% and 77%. The negative predictive value was 93%. Pulse pressure assessed by sphygmomanometry provided important clinical information. A wide pulse pressure in patients with MS was associated with a high incidence of CAD.     

Hypnosis and attention deficits after closed head injury

In a controlled study of patients attending a concussion clinic because of ongoing postconcussion symptoms, attention deficits were recorded in the head-injured group for the aspects of alertness, assessed by the Continuous Performance Test (CPT), and processing capacity, assessed by a version of the Paced Auditory Serial Addition Test (PASAT). Selective attention was intact. Hypnotizability was assessed by the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A), with normal means and standard deviations found in both the concussed and control groups. There was a significant correlation, however, between HGSHS:A scores and PASAT scores in the concussed group only. The results of this preliminary study suggest that slower processing capacity after a closed head injury may predict higher hypnotizability and that hypnosis could be an appropriate rehabilitation technique for these patients who present with postconcussion symptoms.     

Reactive distillation for methyl acetate production

We describe a hierarchy of methods, models, and calculation techniques that support the design of reactive distillation columns. The models require increasingly sophisticated data needs as the hierarchy is implemented. The approach is illustrated for the production of methyl acetate because of its commercial importance, and because of the availability of adequate published data for comparison. In the limit of reaction and phase equilibrium, we show (1) the existence of both a minimum and a maximum reflux, (2) there is a narrow range of reflux ratios that will produce high conversions and high purity methyl acetate, and (3) the existence of multiple steady states throughout the entire range of feasible reflux ratios. For finite rates of reaction, we find (4) that the desired product compositions are feasible over a wide range of reaction rates, up to and including reaction equilibrium, and (5) that multiple steady states do not occur over the range of realistic reflux ratios, but they are found at high reflux ratios outside the range of normal operation. Our calculations are in good agreement with experimental results reported by Bessling et al., [Chemical Engineering Technology 21 (1998) 393].     

Binding of 4-methylumbelliferyl alpha-D-mannopyranoside to tetrameric concanavalin A Fluorescence temperature-jump relaxation study

The kinetics of saccharide binding to the treatment form of concanavalin A have been studies at pH 7.2 with the temperature-jump method. 4-Methylumbelliferyl alpha-D-mannopyranoside was used as a ligand; its fluorescence is totally quenched upon binding. A single relaxation of ligand fluorescence (tau = 20-400 ms) was observed and was investigated at three different temperatures, using kinetic titration and dilution types of experiments. The concentration dependence of the relaxation time and amplitude was consistent with a single-step bimolecular association and independent binding sites. In the temperature range 13-24 degrees C the association and dissociation rate parameters are in the range (6-10) X 10(4) M-1 s-1 and (1.4-3.2)s-1 respectively, corresponding to activation energies for the forward and reverse reactions equal to approx. 13 and 8 kcal/mol (54 and 33 kJ/mol) respectively. Two additional relaxations of protein fluorescence (3 ms and larger than 1 s at 25 degrees C) were unaffected by carbohydrate binding. Tetrameric concanavalin A shows carbohydrate binding parameters that are almost identical to those of native or derivatized dimeric concanavalin A.     

Microstructural investigations of PBT/nylon 6,6 composites

The microstructure of composites made from blends of poly(p-phenylene benzobisthiazole) [PBT] and nylon 6,6 has been investigated with wide-angle X-ray diffraction, selected area electron diffraction, and small-angle X-ray scattering techniques. The composite samples investigated were spun in both fiber and film forms dilute solutions of methane sulfonic acid. The structure of the composites was found to be a microfibrillar network of PBT in a matrix of partially crystalline nylon 6,6. The diameters of the PBT microfibrils were in the range of 30 to 70 Å.     

African American leadership groups: smoking with the enemy

BACKGROUND: Among all racial and ethnic groups in the USA, African Americans bear the greatest burden from tobacco related disease. The tobacco industry has been highly influential in the African American community for decades, providing funding and other resources to community leaders and emphasising publicly its support for civil rights causes and groups, while ignoring the negative health effects of its products on those it claims to support. However, the industry's private business reasons for providing such support were unknown. OBJECTIVE: To understand how and for what purposes the tobacco industry sought to establish and maintain relationships with African American leaders. METHODS: Review and analysis of over 700 previously secret internal tobacco industry documents available on the internet. RESULTS: The tobacco industry established relationships with virtually every African American leadership organisation and built longstanding social connections with the community, for three specific business reasons: to increase African American tobacco use, to use African Americans as a frontline force to defend industry policy positions, and to defuse tobacco control efforts. CONCLUSION: As the tobacco industry expands its global reach, public health advocates should anticipate similar industry efforts to exploit the vulnerabilities of marginalised groups. The apparent generosity, inclusion, and friendship proffered by the industry extract a price from groups in the health of their members. Helping groups anticipate such efforts, confront industry co-optation, and understand the hidden costs of accepting tobacco industry largesse should be part of worldwide tobacco control efforts.