Direct measurement of the pH in the stomach of the conscious rat, using a special electrode.

The construction and use of a specially designed electrode to measure gastric pH in the conscious rat is described. Measurement of gastric hydrogen ion activity with this device is rapid and reproducible in starved rats. A dose-related increase of gastric pH was obtained after s.c. injection of the anticholinergic isopropamide.     

Gastric acid secretory responses of acute gastric fistula preparation in anesthetized young chickens

Summary A reliable technique which permits quantitative determination of the gastric acid secretory responses to drugs was developed in anesthetized young chickens.The present study was supported by a Grant from the Ministry of Education of Japan. We are indebted to Mr.M. Murakami, Mr.S. Kojima and MissU. Kariya, for their technical assistance.     

Demonstration of fructose 1,6-bisphosphatase in human term placenta.

A proteolysed form of fructose 1,6-bisphosphatase (Fru-P2ase) has been detected and characterized in human term placenta. The extract was found to contain very low levels of activity with an alkaline pH optimum. Western blotting demonstrated a polypeptide of Mr 26,000, instead of the subunit of Mr 36,000 observed in native mammalian Fru-P2ases.     

A rotating bottle culture method with continuous replacement of the gas phase

Summary A rotator culture method is described which provides a continuous flow of oxygenating gas to cultures in rotating bottles. The system maintains constant O₂ and CO₂ levels in the culture medium throughout the incubation period. It also provides a more stable pH than systems with sealed culture bottles.Acknowledgments. We would like to thank Mr B. Secker, Mr C. Hellon and Mr S. J. Ellis, of the Physiological Laboratory workshop, for constructing the rotator apparatus. We also thank the Medical Research Council, London, for financial support for the project.     

The effect of a gastric mucus barrier on the dynamic response of a pH electrode

Hydrogen ion mobility in gastric mucus has been found to be reduced to a greater extent than that hitherto suspected, though at low pH (less than 4) and in buffer this mobility increases. Mucus, at an optimized pH, may therefore protect the gastric mucosa from acid digestion by providing a diffusion barrier.     

Cytoprotective effects of acidosis via heat shock protein HSP27 against the anticancer drug doxorubicin

Drug resistance continues to be a stumbling block in achieving better cure rates in several cancers. Doxorubicin is commonly used in treatment of a wide range of cancers. The aim of this study was to look into the mechanisms of how low ambient pH may contribute to down-regulation of apoptotic pathways in a gastric tumour cell line. Low pH culture conditions were found to dramatically prolong cell survival after doxorubicin treatment, an effect that was in part reversed by co-incubation with the specific p38 mitoge-activated protein kinase (MAP kinase) inhibitor SB203580, only mildly inhibited by blockade of the multi-drug resistance 1 (MDR1) transporter, but completely abolished by siRNA-mediated knockdown of the heat shock protein 27 (HSP27). In conclusion, acidic pH causes less accumulation of cytotoxic drug in the nucleus of adeno gastric carcinoma (AGS) cells and HSP27-dependent decrease in FasR-mediated gastric epithelial tumour cell apoptosis.     

Demonstration of fructose 1,6-bisphosphatase in human term placenta

Summary A proteolysed form of fructose 1,6-bisphosphatase (Fru-P₂ase) has been detected and characterized in human term placenta. The extract was found to contain very low levels of activity with an alkaline pH optimum. Western blotting demonstrated a polypeptide of Mr 26,000, instead of the subunit of Mr 36,000 observed in native mammalian Fru-P₂ases.     

Inhibition in the rat of gastric acid secretion and cyclic AMP analogs accumulation in vitro by somatostatin

Summary Various somatostatin (S) analogs exhibited similar degree and similar, or shorter, duration of inhibition of basal gastric acid secretion as S in the unanesthetized rat and similar, or less, inhibition of the cyclic AMP accumulation induced by prostaglandin E₂ in the rat anterior pituitary in vitro. With the analogs examined, the gastrointestinal and pituitary receptors appear to exhibit generally similar recognition specificity with the differences within the gastrointestinal activities reflecting duration of availability rather than receptor affinity.The author acknowledges the technical assistance of Mr L. Chamberland, Miss A. Colaviti and Miss C. Pilapil.     

Hydrochloric acid secretion of fetal rat gastric mucosa]

In Rat, spontaneous secretion of hydrochloric acid by gastric mucosa takes place before birth. From day 20 of gestation until birth, the pH of gastric content markedly decreases, reaching 3 pH-units in newborns. During this period, Cl- concentration in gastric juice increases, while p-CO2 remains constant.     

Attraction ofScolytus scolytus (F.) to the components of Multilure,the aggregation pheromone ofS. multistriatus (Marsham) (Coleoptera: Scolytidae)

Summary The attraction ofS. scolytus to the components of Multilure is described. 4-Methyl-3-heptanol is an attractant which is synergised bya-cubebene. Multistriatin appears to be an inhibitor. A combination of 4-methyl-3-heptanol and cubeb oil is more effective as a bait forS. scolytus than Multilure.We thank Mr A. K. Hughes and Mr J. Boswell for their cooperation in allowing us to conduct experiments on Parham Estate; Mr D. Mobbs and Mr C. Thorne for the statistical analyses; Dr J. W. Peacock for samples of mixed isomers of multistriatin and distilled cubeb oil; Mrs J. Allsop and Mr N. J. Fielding for technical assistance. We are grateful to Mr D. Bevan, Dr J. H. Borden, Dr J. F. Grove and Prof. A. W. Johnson for their interest and encouragement.     

Effect of experimental chronic renal failure upon the production of urea,as measured by the liver arginase activity in rats

Summary A significant diminution in liver arginase activity of chronic renal failure uremic rats is described, thus implying that the experimental finding of an increased urea production is not due to a depressed arginase activity.This work was supported by the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico do Brasil's Grants. —Acknowledgments. We are indebted to Mr D'Arrochela Lobo for technical assistance, Mr Celso Chiarin for the statistical review and Dr C.E. Tosta and Dr Linda Caldas for helpful advice.     

Structure of the porcine thyrotropin receptor: a 200 kilodalton glycoprotein heterocomplex

We have determined that the porcine thyroidal TSH receptor is a glycoprotein heterotetramer composed of two Mr approximately 35,000 (epsilon) covalently linked subunits which interact noncovalently with two copies of delta (Mr 66,000) chains.     

Structure of two biologically active sesquiterpenoid amino-quinones from the marine spongeDysidea avara

Summary The structures of 2 minor constituents of the marine spongeDysidea avara, which induce developmental aberrations in sea-urchin eggs, are described. The structures were confirmed also by a simple synthesis from avarol (1).Acknowledgments. The authors wish to thank Mr A. Crispino for his skillfull laboratory technical assistance. Thanks are also due to Mr C. Di Pinto (NMR) and Mr A. Milone (MS).     

A method for the detection of chemotaxis in mammalian tissue cells

Summary A new method is described of culture of mammalian tissue cells beneath a solid medium, permitting the assessment of growth-promoting, growth-inhibiting and chemotactic substances.Our thanks are due to Mr.D. S. Leake, who provided the smooth muscle cell suspensions; and to Mr.J. F. Stevenson, for expertise in preparing the medium. This work is supported by the British Heart Foundation, Grant No. 528.     

The chromosomes of the southern hemispheric lamprey,Geotria australis Gray

Summary Approximately 180 small and mainly acrocentric chromosomes are present inGeotria australis (Geotriidae) from the southern hemisphere. This is closer to the situation found in northern hemispheric species (Petromyzonidae) than in other southern hemispheric lampreys (Mordaciidae).We wish to express our gratitude to Mr R. W. Hilliard and Mr D. J. Bird for technical help. Financial assistance was provided by the Australian Research Grants Committee.     

Human chromosomal heteromorphism in American blacks. V. Racial differences in size variation of the short arm of acrocentric chromosomes

Summary Normal American blacks were studied by the RFA (R-bands by fluorescence using acridine orange) technique to estimate the frequency of size variation of the short arm of acrocentric chromosomes and to compare the data on Caucasians.Acknowledgments. Supported by NCI contract N01-CP-43251. Technical assistance of Mr Jorge Rodriguez and Mr Norman Schmidt is gratefully appreciated.     

Effect of seasonal variation on the acute toxicity of cyclophosphamide in the Chinese hamster (Cricetulus griseus) and the mouse under laboratory conditions

Summary The acute toxicity of cyclophosphamide, studied orally in chinese hamsters and intravenously in Tif: MAGf (SPF) mice, showed seasonal variation in Chinese hamsters but not in mice.Acknowledgement. I thank Mr R. Gebus for skilful technical and Mr A.P. Grieve for statistical assistance.     

Sialidase of transitional epithelium of sheep urinary tract

Resumen El epitelio de transición de cordero contiene actividad de sialidasa. Se demuestra que esta enzima se encuentra en lisosomas de este tejido y posee el pH óptimo ácido característico de enzimas lisosomales.

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The technical assistance of MissE. Prado and Mr.L. Iwakawa is acknowledged. This investigation was supported by a grant of the Consejo Nacional de Investigaciones Cientificas y Técnicas of Argentina.     

Fine structure of modiffied phtoreceptor cells in the pineal of the gobyClevelandia ios (Pisces: Gobiidae)

Summary Photoreceptor cells with a system of long, thi cytoplasmic processes (50–80 nm thick), which amy represent a modification of the outer segment saccules, are described in the pineal of the goby,Clevelandia ios.The author wishes to thank Mr Larry Allen, who helped collect the specmens, and Mr Kyle Kikuchi, who was instrucmental in the preliminary studies.Partial support by Biomedical Research Support Grant (NIH) No. 447-12-000 from the Stritch School of Medicine is gratefully acknowledged.     

A scanning electron microscopic study of the air and blood capillaries of the lung of the domestic fowl (Gallus domesticus)

Summary Air and blood capillaries of the lung of the domestic fowl constitute the functional gas exchange units. They anastomose profusely and interlace with each other in 3 dimensions. Air capillaries are not blind-ending tubules as has occasionally been suggested. I am most grateful to: Mr K. Veltkamp for aid with SEM, Dr M.A. Abdalla for help with injections, Prof. A.S. King for critical suggestions, Mr J. Geary for aid with photography.