Ametropic efficiency of visual pathway neurons

Zusammenfassung Bestimmung der Auswirkung von artefiziellen Refraktionsanomalien auf die Aktivität von Neuren in primären Sehzentren.

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This work was supported by U.S.P.H.S. Grant No. EY00576.     

A diploid population ofPoa annua L. from Australia

Résumé On décrit une population diploide dePoa annua L. d'Australie. Elle se montre différente des «mphihaploides» qui ont été trouvées en Californie. La signification de cette population en rapport avec l'origine supposée deP. annua est considerée.

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Acknowledgement. This work was supported by a grant from the Nuffield Foundation.     

Visual cortical cells: How critical is focus?

Zusammenfassung Nachweis, dass rezeptive Kortexfelder der Kaninchen (70% der visuellen Zellen) auf Lichtstimuli bzw. Schärfe-Unschärfe-Änderung mit Amplitudenabfall reagieren.

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This work was supported by U.S.P.H.S. Grant No. EY00576.     

Compensatory caspase activation in MPP+-induced cell death in dopaminergic neurons

Many have hypothesized that cell death in Parkinsons disease is via apoptosis and, specifically, by the mitochondrial-mediated apoptotic pathway. We tested this hypothesis using a mouse dopaminergic cell line of mesencephalic origin, MN9D, challenged with the Parkinsonism-causing neurotoxin MPP⁺ (1-methyl-4-phenylpyridinium ion). Apoptosis was the main mode of cell death when the cells were subjected to MPP⁺ treatment under serum-free conditions for 24 h. Caspase-3 and caspase-9, however, were not activated, thus indicating the existence of alternate or compensatory cell death pathway(s) in dopaminergic neuronal cells. Using caspase inhibitors, we demonstrated that these pathways involve caspase-2, –8, –6 and –7. A time-course study indicated that activation of caspase-2 and –8 occurred upstream of caspase-6 and caspase-7. Upon MPP⁺ challenge, the apoptosis-inducing factor was translocated from the mitochondria into the MN9D cytosol and nucleus. These results suggest the existence of alternative apoptotic pathways in dopaminergic neurons.Received 20 September 2004; received after revision 5 November 2004; accepted 22 November 2004     

Phosphodiesterase: overview of protein structures, potential therapeutic applications and recent progress in drug development

Phosphodiesterases (PDEs) are essential regulators of cyclic nucleotide signaling with diverse physiological functions. Because of their great market potential and therapeutic importance, PDE inhibitors became recognized as important therapeutic agents in the treatment of various diseases. Currently, there are seven PDE inhibitors on the market, and the pharmacological and safety evaluations of many drug candidates are in progress. Three-dimensional (3D) structures of catalytic domains of PDE 1, -3, -4, -5 and -9 in the presence of their inhibitors are now available, and can be utilized for rational drug design. Recent advances in molecular pharmacology of PDE isoenzymes resulted in identification of new potential applications of PDE inhibitors in various therapeutic areas, including dementia, depression and schizophrenia. This review will describe the latest advances in PDE research on 3D structural studies, the potential of therapeutic applications and the development of drug candidates.Received 30 November 2004; received after revision 24 January 2005; accepted 5 February 2005     

Atypical base composition of foldback DNA

Summary Salmon, calf and human foldback DNAs all exhibited hypermethylation, reduced adenine plus thymine content and an excess of adenine over thymine when compared with their respective native DNAs. The only unusual feature of the base composition of wheat germ foldback DNA was the excess of thymine over adenine.This work was supported by grants from the Committee on Higher Degrees and Research Grants and the Department of Pathology, University of Hong Kong.This study was carried out in partial fulfillment of the requirements of the University of Hong Kong for the degree of Doctor of Philosophy.     

The effect of hog gastrin on gastric secretion in chronic gastric fistula rats

Résumé L'action de la gastrine de porc a été étudiée chez des rats mâles munis de fistules gastriques. La gastrine était injectée par voie s.c. à des doses de 1–2 ml: 1 ml équivalant à l'activité de 10 g de muqueuse de porc. Le volume de suc gastrique, le volume de suc gastrique par 100 g, l'acidité totale et le débit d'acide accusèrent une pointe dans la première h, alors que la concentration en acide atteignit son maximum vers la troisième h. Le débit de la pepsine diminua entre la troisième et la cinquième h et augmenta légèrement entre la cinquième et la sixième h.

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This research was supported in part by grants from the National Science Foundation (No. GB 6105) and from the AMA ERF, to J. H. T. — Dr.Robitscher of Ayerst Laboratories kindly supplied the ICI-50123.