The activity of sorbitol dehydrogenase in some mammalian erythrocytes

Summary The activity of sorbitol dehydrogenase was found to be high in the red blood cells of man, dog, guinea-pig and mouse and comparatively lower in those of goat, sheep, rabbit, cat and rat.     

Differential sensitivity to tributyltin of cytochrome-containing and cytochrome-deficient cells ofEscherichia coli SASX76

Summary The effect of tributyltin (TBT) chloride on the growth of cytochrome-deficient and cytochrome-containing cells ofEscherichia coli SASX76 was examined. The former cells were found to be at least 20 times more sensitive to TBT. It is proposed that the differential sensitivity of these two cell types to the biocide, TBT, may be due to a different mode of energy generation by cytochrome-deficient and cytochrome-sufficient cells. In addition to the energy state, the pH change caused by the presence and absence of cytochromes which occurred during growth also resulted in a differential sensitivity of these cells.Acknowledgments. This research was financially supported by a grant from the University Grants Commission, New Delhi, India, to APS. The authors thank the Head, Department of Botany, B.H.U. for facilities.     

Differential sensitivity to tributyltin of cytochrome-containing and cytochrome-deficient cells of Escherichia coli SASX76

The effect of tributyltin (TBT) chloride on the growth of cytochrome-deficient and cytochrome-containing cells of Escherichia coli SASX76 was examined. The former cells were found to be at least 20 times more sensitive to TBT. It is proposed that the differential sensitivity of these two cell types to the biocide, TBT, may be due to a different mode of energy generation by cytochrome-deficient and cytochrome-sufficient cells. In addition to the energy state, the pH change caused by the presence and absence of cytochromes which occurred during growth also resulted in a differential sensitivity of these cells.     

X-ray sensitivity of human cultivated lymphoblastic cells in media enriched in nickel sulfate]

Human leukaemic cells of the established line REH, cultured in media supplemented by nickel suplhate have been irradiated by X-Rays. The nickel sulphage and the X-rays have toxic effects that appear as independent or interdependent effects according to the X-ray doses, the nickel sulphate concentration and the nickel sulphate action endurances.     

Differential sensitivity of the two phases of ear artery contraction to intimal and adventitial norepinephrine

Summary The biphasic contraction of the rabbit ear artery to norepinephrine (NE) was investigated in the normal (adventitial stimulation) and the everted (intimal stimulation) segment of ear artery. The 2nd phase response showed an intimal ED₅₀ of 8.2×10^–8 M which was significantly (p<0.05) lower than the adventitial ED₅₀ of 42.6×10^–8 M. This difference was abolished by inhibition of neuronal and extraneuronal uptake for NE. The 1st phase response also showed an ED₅₀ for the intimal stimulation (6.9×10^–8 M) which was significantly (p<0.05) lower than adventitial (65.5×10^–8 M). This difference was reduced but not abolished by NE uptake inhibition. This suggsets that some feature of the adrenergic neuroeffector apparatus is asymmetrically arranged to favor fast responses to blood borne NE.Supported by American Heart Association-Greater Los Angeles Affiliate Grant No. 602. We wish to thank Dr John Bevan and Dr Alasdair MacLean for helpful advice.     

Differential sensitivity of amphibian nodal and paranodal K+ channels to 4-aminopyridine and TEA

Summary Voltage-dependent K⁺ channels are blocked by several drugs, including 4-aminopyridine (4-AP) and tetraethylammonium (TEA). 4-AP is most widely used to localize K⁺ channels in mammalian and non-mammalian nerve fibers, but 4-AP and TEA alter various K⁺ channels and/or preparations in specific ways. The reason is not known, in part because dissociation constants for 4-AP and TEA have not been measured for nodal and internodal K⁺ channels in the same fibers. Smith and Schauf showed that the density of nodal versus paranodal K⁺ channels in frog nerves depends on fiber diameter. This size dependence was used to determine the relative sensitivity of nodal and internodal K⁺ channels to 4-AP and TEA, and to compare voltage- and time-dependent activation. The results show nodal and internodal K⁺ channels activate similarly. However, internodal channels are selectivity blocked by 4-AP while TEA is more effective on nodal channels. A high sensitivity of internodal K⁺ channels may explain why 4-AP improves symptoms in diseases such as multiple sclerosis.     

Differential sensitivity of amphibian nodal and paranodal K+ channels to 4-aminopyridine and TEA

Voltage-dependent K+ channels are blocked by several drugs, including 4-aminopyridine (4-AP) and tetraethylammonium (TEA). 4-AP is most widely used to localize K+ channels in mammalian and non-mammalian nerve fibers, but 4-AP and TEA alter various K+ channels and/or preparations in specific ways. The reason is not known, in part because dissociation constants for 4-AP and TEA have not been measured for nodal and internodal K+ channels in the same fibers. Smith and Schauf showed that the density of nodal versus paranodal K+ channels in frog nerves depends on fiber diameter. The size dependence was used to determine the relative sensitivity of nodal and internodal K+ channels to 4-AP and TEA, and to compare voltage- and time-dependent activation. The results show nodal and internodal K+ channels activate similarly. However, internodal channels are selectivity blocked by 4-AP while TEA is more effective on nodal channels. A high sensitivity of internodal K+ channels may explain why 4-AP improves symptoms in diseases such as multiple sclerosis.     

Magnetochemical behaviour of some substances used in the medical treatment of tumors

Sommario Fu misurata la suscettività diamagnetica di alcune sostanze usate nella chemioterapia dei tumori con lo scopo di confrontare i risultati così ottenuti coi valori della stessa calcolati in base alle sistematiche magnetochimiche. Nei limiti di precisione consentiti dalle conoscenze attuali di queste sistematiche, si è potuto notare una divergenza fra valori osservati e calcolati tale da indurre ad ammettere l'esistenza di anomalie strutturali, precisamente di irregolarità della nube elettronica inerente alle molecole delle sostanze esaminate.     

On the nature of some smooth muscle active substances from the platelets

Zusammenfassung In einer früheren Arbeit wurde das Thrombozytolysin beschrieben, eine Substanz, die aus Pferde-Thrombozyten nach Einwirkung des homologen Thrombozytenantikörpers freigesetzt wird. Die in dieser Arbeit berichteten experimentellen Resultate berechtigen zur Schlussfolgerung, dass das Thrombozytolysin mit Serotonin (5-hydroxytryptamin) nicht identisch ist.     

Interaction of lead with erythrocytes

Zusammenfassung Untersuchungen mit²⁰³Pb in vitro ergeben, dass Blei in den Erythrozyten vorwiegend an Hämoglobin gebunden wird, während Stromasubstanzen kein Blei aufnehmen.     

Synthesis and some characteristics of [13C]-specially enriched tetragastrin and the related compound

Summary [¹³C]-enriched tetragastrin and the related compound were synthesized in solution. Conversion of S-[¹³C]-methylated tetragastrin to the enriched tetragastrin gave 10.5 ppm upfield chemical shift of C resonance. The potency of the synthetic tetragastrin to stimulate gastric acid secretion was virtually identical with that of pentagastrin (ICI).Acknowledgment. A part of this research was supported by scientific research funds (No. 944059, 048253) from the Japanese Ministry of Education.