High-performance liquid chromatographic determination of papaverine in whole blood

The development and application of an assay method for papaverine in whole blood is reported. A single, simple extraction procedure at pH 10.0 using chloroform—n-hexane (2:3) as the solvent, results in pure extracts which can be chromatographed without further purification. Chromatography is performed on a nitrile-bonded phase, using n-hexane—dichloromethane—acetonitrile—propylamine (50:25:25:0.1) as mobile phase. This method is characterized by a between-day precision of 4% at the 200 ng/ml level and a detection limit of 5 ng/ml, and was successfully applied in a pharmacokinetic study.     

SOME PRINCIPLES OF TSETSE CONTROL AND LAND-USE WITH EMPHASIS ON WILDLD7E HUSBANDRY

Natural animal populations are adapted to and in equilibrium with their natural environment. Sudden changes in composition of flora or fauna of climax communities may cause serious consequences and even the collapse of the system. This is especially true in Africa where shallow soil and precarious energy cycles are easily upset. With this in mind, it is suggested that serious consideration be given in tsetse-control schemes and land-use plans to the feasibility of game-farming, especially when marginal lands are involved. It would be advantageous in many instances to keep all large and some smaller tracts of marginal lands for wildlife conservation purposes; the large areas as national parks and as a valuable source of government income and prestige, the smaller areas as a permanent animal-protein supply through game-harvesting operations. The advantages of game-farming over domestic livestock-raising are discussed in detail. A schematized tsetse-control plan is also presented as an example of land-use in savannah tsetse belts.     

Catalytic Efficiency,Structure, and Recycling Behavior of Electrospun Polyvinyl Alcohol-Xylanase Fibers Cross-Linked by Glutaraldehyde

Food Biophysics - A versatile and effective method of producing polyvinyl alcohol (PVA)-xylanase (XY) fibers cross-linked by glutaraldehyde vapor (GA) is reported in the present study. Crosslinking...     

Immunologists getting nervous: neuropeptides, dendritic cells and T cell activation

It is increasingly recognised that the immune and nervous systems are closely integrated to optimise defence systems within the lung. In this commentary, the contribution of various neuropeptides such as substance P, calcitonin gene-related peptide, vasoactive intestinal peptide and somatostatin to the regulation of T cell activation is discussed. These neuropeptides are released not only from nerve endings but also from inflammatory immune cells such as monocytes, dendritic cells, eosinophils and mast cells. On release they can exert both direct stimulatory and inhibitory effects on T cell activation and also indirect effects through their influence on the recruitment and activation of professional antigen-presenting dendritic cells. Neuropeptides should therefore be included in the conceptual framework of the immune regulation of T cell function by dendritic cells.