Pregnancy reduces noradrenaline but not neuropeptide levels in the uterine artery of the guinea-pig

Summary Using histochemical, immunohistochemical and biochemical techniques, noradrenaline-, neuropeptide Y-, vasoactive intestinal polypeptide-, substance P- and calcitonin gene-related peptide-containing nerve fibres were studied in the uterine artery of virgin, progesterone-treated and pregnant guinea-pigs. Morphological changes following hormone treatment or in pregnancy were also evaluated in a quantitative study on semithin sections of the uterine artery. In late pregnancy, the number of noradrenalinecontaining nerve fibres, which formed the densest plexus in virgin animals, was significantly decreased, a finding supported by a significant reduction in noradrenaline levels. This reduction was not mimicked by systemic progesterone treatment. In contrast, the innervation of the uterine artery by neuropeptide Y-containing nerve fibres was increased in pregnancy, while the other peptidergic nerves and peptide levels were unchanged after progesterone treatment and in pregnancy. These changes led to a predominance of innervation by neuropeptide Y- rather than noradrenaline-containing nerve fibres in late pregnancy. No morphological changes were detected following progesterone treament, but pregnancy led to a marked increase in the cross-sectional area of the vessel accompanied by an increase in the thickness of the media.     

Performance of parallel communication and spawning primitives on a Linux cluster

The Linux cluster considered in this paper, formed from shuttle box XPC nodes with 2 GHz Athlon processors connected by dual Gb Ethernet switches, is relatively easily constructed, but, while effective as a throughput engine, may result in disappointing results when running explicitly parallel software if weakly-performing communication mechanisms and process spawning are selected. This paper carefully compares the implementations of communication and spawning primitives in MPICH-2, openMosix, and Linux Remote Procedure Call, forking, and various lower-level communication mechanisms. The test selection compares the provision of both a message-passing library, and a single system image software package, with direct use of lower-level primitives. The information in the paper will be of interest to those considering the use of one of the well-known packages, or directly writing their own distributed applications, or constructing a distributed language by layering on top of an existing set of parallel primitives. The results expose a ranking in terms of process spawning and a similar ranking of communication software performance. They reveal poor performance in certain circumstances, well below the hardware specification, which it is as well that the developer is aware of. In general, the paper emphasizes the importance of efficient transport software to cluster machines. David J. Johnston has worked as software engineer in research and development for 20 years, at ICL Ltd. and the Rutherford-Appleton Laboratory, UK. His strengths lie in generating and realizing algorithms for complex systems. His interests include languages and methodologies to shorten the software development process. He has recently completed a Ph.D. at the University of Essex, UK in position identification for augmented reality. He has co-authored a book on Computer Graphics. Martin Fleury is a Senior Lecturer at the University of Essex, UK, where he was also awarded a Ph.D. in Parallel Image Processing. His first degree was from Oxford University, and he holds an MSc in Astrophysics from the University of London. He is the principal author of a book on parallel computing for embedded systems. He has authored thirty-five journal papers in the last ten years on parallel image and vision processing, performance prediction, real-time systems, reconfigurable computing, software engineering, and video and document compression. Michael Lincoln has completed an M.Sc. and Ph.D. at the University of Essex, UK in the field of face recognition and face tracking. His work as a Senior Research Officer is concerned with radar control of aircraft landings. The cluster mentioned in the paper was constructed, configured, and commissioned by Michael. Andrew C. Downton was educated at Southampton University, UK, where he obtained a first class honours degree in Electronic Engineering in 1974, and a Ph.D. in 1982, and where he was also a lecturer. In 1995 he was promoted to a personal Chair at the University of Essex, UK, and in 1999 he became Head of the Department of Electronic Systems Engineering at Essex. His research interests include pattern recognition and image analysis; parallel computer architectures; hardware-software co-design; handwriting recognition; and document analysis. He is a Chartered Engineer and Fellow of the Institution of Electrical Engineers (IEE) and a Senior Member of the IEEE.     

Boophilus microplus: characterization of enzymes introduced into the host.

A number of enzymes, presumably secreted by larvae of B. microplus under natural feeding conditions, have been investigated in the skin of previously unexposed calves 4 h after infestation at the attachment site. Carboxylic ester hydrolase activity was demonstrated in the dermis, immediately adjacent to the mouthparts, or in the attachment cone, depending on substrate and reaction pH. The carboxylic ester hydrolase acting on naphthol AS-D acetate (2-acetoxy-3-naphthoic-O-toluidide) at pH 7-1 was characteristically found in the dermis and not in the attachment cone. The use of specific inhibitors showed that this enzyme was primarily a B-esterase or carboxylesterase with possibly a small portion of C-esterase or acetylesterase. It is postulated that carboxylic ester hydrolase could contribute to the dilation observed in the subepidermal capillaries adjacent to the attachment sites of unexposed animals, through the formation of plasma kinins. Other enzymes demonstrated in the dermis, adjacent to the mouthparts, were triacylglycerol lipase, as an aggregated deposit, and small amounts of aminopeptidase (microsomal) and monophenol monooxygenase. Aminopeptidase (microsomal) was also demonstrated in the attachment cone or adjacent epidermis, according to the substrate used. No activity was found in the host tissue, in association with the attachment site, for either alkaline or acid phosphatase, acetylcholinesterase or cholinesterase, peroxidase or amine oxidase (flavin-containing), despite the intense histochemical reaction for the latter in the tissues of larvae.     

A Precise Method for Replicating Suspension Cultures of Mammalian Cells

A simple, readily assembled shaker-culture system for the cultivation of mammalian cells is described. No specialized glassware and equipment were used in this system, which consists of an Erlenmeyer flask fitted with a breather-sampling assembly. This unit was employed to quantitate the effects of several variables, including medium ingredients, serial transfers, and freezing and storage on two variants of the L-cell line. This system is reproducible and precise and allows for growth of cells in suspension for extended periods of time. Large numbers of cells can be mass-produced. Many replicates can be run simultaneously to yield data for statistical analysis.     

Growth of Human Lymphoid Cells (Raji Strain) in a Five-Liter Fermentor

Procedures used to produce an established line of mammalian cells (L cell) in a New Brunswick fermentor were adapted to propagate human lymphoid cells in suspended culture. Control of pH within defined limits was more effective for regulation of cell metabolism than control of oxidation-reduction potential. An unusually high rate of agitation was required.     

Immunological characterization of embryonic cell surface antigens recognized by antiblastocyst serum

Stage-specific cell surface antigens expressed during mouse preimplantation development and detected by a rabbit antiserum prepared against mouse blastocysts (A-BL₂) have been characterized by serological and biochemical techniques. Immunofluorescence, immunoradiolabeling, and complement-mediated cytotoxicity assays reveal the expression of A-BL₂ surface antigens beginning at the 4-cell stage and reaching a maximum at the 8-cell to morula stages. At earlier times in development A-BL₂ antigens are not detectable, and there is a decline in expression at the blastocyst stage. No antibody reactivity is detected against adult mouse tissues or teratocarcinoma cell lines. The presence of A-BL₂ antibodies during in vitro embryo culture interferes with normal development. Treatment of embryos with β-N-acetylglucosaminidase, but not other glycosidases, proteases, or lipases, results in a quantitative decrease in the binding of A-BL₂ antibodies to surface antigens. Immunoprecipitation and electrophoretic analyses of A-BL₂ antigens demonstrate specific antibody activity against a pair of embryonic glycoproteins of 65,000 to 70,000 daltons which can be metabolically labeled with ³⁵S-methionine and ³H-glucosamine. Tunicamycin treatment alters the form of the A-BL₂ immunoprecipitate to a single 60,000-dalton protein.