STUDIES ON THE ISOLATION OF SPIRILLUM SPUTIGENUM

1957 ◽  
Vol 3 (5) ◽  
pp. 679-686 ◽  
Author(s):  
J. B. Macdonald ◽  
E. M. Madlener
Keyword(s):  
Surface Layer ◽  
Gold Foil ◽  
Selective Inhibition ◽  
Inhibitory Effect ◽  
Sodium Lauryl Sulphate ◽  
Surface Films ◽  
Oral Flora ◽  
Oxidation Reduction ◽  
Marked Inhibitory Effect ◽  
Reducing Substances

Three approaches were used in attempting to improve the method of isolating Spirillum sputigenum from the human oral cavity:(1) attempts to induce spreading surface growth;(2) selective inhibition of interfering organisms;(3) adjustment of oxidation–reduction potentials.Five of eight strains of Spirillum sputigenum grew as spreading surface films on a blood agar medium in which the base was a veal heart infusion. Increase in the amount of spread could not be induced by varying the agar content of the medium. Sodium lauryl sulphate (0.01%) was found to have a marked inhibitory effect on the human oral flora but did not inhibit Spirillum sputigenum. A method of recording potentials of the surface layer of solidified media using a gold foil electrode is described. Changes in potential of the surface layer of a number of media during reduction in a Brewer jar are recorded. Media in which the potential was rapidly reduced supported growth of Spirillum sputigenum. Of several reducing substances added to media, sheep's serum was the most effective in accelerating a drop in potential. Using a medium compounded of veal heart infusion, sodium lauryl sulphate, and sheep's serum, Spirillum sputigenum was recovered in pure culture from 16 out of 21 samples of gingival scrapings.

Selective Inhibition of Thromboxane Synthetase with Dazoxiben - Basis of Its Inhibitory Effect on Platelet Adhesion

1983 ◽  
Vol 49 (02) ◽  
pp. 096-101 ◽  
Author(s):  
V C Menys ◽  
J A Davies
Keyword(s):  
Arachidonic Acid ◽  
Platelet Adhesion ◽  
Fold Increase ◽  
Selective Inhibition ◽  
Inhibitory Effect ◽  
Selective Inhibitor ◽  
Coated Glass ◽  
Thromboxane Synthetase ◽  
Pre Treatment

SummaryPlatelet adhesion to rabbit aortic subendothelium or collagen-coated glass was quantitated in a rotating probe device by uptake of radio-labelled platelets. Under conditions in which aspirin had no effect, dazoxiben, a selective inhibitor of thromboxane synthetase, reduced platelet adhesion to aortic subendothelium by about 40% but did not affect adhesion to collagen-coated glass. Pre-treatment of aortic segments with 15-HPETE, a selective inhibitor of PGI2-synthetase, abolished the inhibitory effect of dazoxiben on adhesion. Concentrations of 6-oxo-PGFlα in the perfusate were raised in the presence of dazoxiben alone, and following addition of thrombin (10 units/ml) there was a 2-3 fold increase in concentration. Perfusion of damaged aorta with platelets labelled with (14C)-arachidonic acid in the presence of thrombin and dazoxiben resulted in the appearance of (14C)-labelled-6-oxo-PGFiα. Inhibition of thromboxane synthetase limits platelet adhesion probably by promoting vascular synthesis of PGI2 from endoperoxides liberated from adherent platelets, which subsequently promotes detachment of cells from the surface.

Coadsorption of bulky ions by surfactants. Monomolecular layers of tris(2,2'-bipyridyl)ruthenium(II) complex with sodium lauryl sulphate on glassy carbon, platinium, n-SnO2, and n-Si electrodes

1984 ◽  
Vol 49 (10) ◽  
pp. 2187-2196 ◽  
Author(s):  
Jan Lasovský ◽  
František Grambal ◽  
Miroslav Rypka
Keyword(s):  
Glassy Carbon ◽  
Complex Cation ◽  
Radiant Energy ◽  
Electric Energy ◽  
Sodium Lauryl Sulphate ◽  
Surface Films ◽  
Order Of Magnitude ◽  
Monomolecular Layers ◽  
Self Association ◽  
Semiconductor Electrodes

The electrochemical and photochemical behaviour of tris(2,2'-bipyridyl)ruthenium(II) complex (I) on glassy carbon, platinium, n-SnO2, and n-Si electrodes in the presence of sodium lauryl sulphate (II) was investigated. The surfactant in low concentrations induces self-association of the complex cation and its accumulation in the electrode-solution interface. At the optimum concentrations of sodium lauryl sulphate (cII ~0.6 mmol l-1) and of the complex (cI < 0.1 mmol l-1), monomolecular layers composed of I, II counterions are formed on the electrodes. The formation of the surface films does not depend on the kind of the electrode and improves the sensitivity of the voltammetric determination of I by as much as an order of magnitude. For the semiconductor electrodes, the surface films enhance the efficiency of conversion of radiant energy into electric energy. The effect under study may participate in the photosynthesis of green plants.

scholarly journals Rostral ventral medulla 5-HT1A receptors selectively inhibit the somatosympathetic reflex

2001 ◽  
Vol 280 (5) ◽  
pp. R1261-R1268 ◽  
Author(s):  
Takashi Miyawaki ◽  
Ann K. Goodchild ◽  
Paul M. Pilowsky
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Sympathetic Nerve Activity ◽  
Selective Inhibition ◽  
Inhibitory Effect ◽  
Ventrolateral Medulla ◽  
Arterial Blood ◽  
Potent Inhibition ◽  
Somatosympathetic Reflex

The role of the 5-hydroxytryptamine (5-HT1A) receptors in the rostral ventrolateral medulla (RVLM) on somatosympathetic, baroreceptor, and chemoreceptor reflexes was examined in anesthetized rats. Microinjection of the selective 5-HT1A agonist 8-hydroxy-di- n-propylamino tetralin (8-OH-DPAT) decreased arterial blood pressure and splanchnic sympathetic nerve activity (SNA). Electrical stimulation of the hindlimb evoked early and late excitatory sympathetic responses. Bilateral microinjection in the RVLM of 8-OH-DPAT markedly attenuated both the early and late responses. This potent inhibition of the somatosympathetic reflex persisted even after SNA and arterial blood pressure returned to preinjection levels. Preinjection of the selective 5-HT1A antagonist NAN-190 in the RVLM blocked the sympathoinhibitory effect of 8-OH-DPAT and attenuated the inhibitory effect on the somatosympathetic reflex. 8-OH-DPAT injected in the RVLM did not affect baroreceptor or chemoreceptor reflexes. Our findings suggest that activation of 5-HT1A receptors in the RVLM exerts a potent, selective inhibition on the somatosympathetic reflex.

The Histidine Requirement of a Normal and a Leukaemia Cell-Line from Man: Comparative Effects on Cell Growth, Metabolism and Composition

1974 ◽  
Vol 15 (2) ◽  
pp. 407-417
Author(s):  
J. B. GRIFFITHS
Keyword(s):  
Cell Growth ◽  
Protein Composition ◽  
Inhibitory Effect ◽  
Leukaemia Cell ◽  
Leukaemia Cell Line ◽  
Marked Inhibitory Effect ◽  
Normal Human ◽  
Therapeutic Enzymes ◽  
Therapy Studies ◽  
Human Leukaemia

The object was to determine whether the depletion of histidine would have a more marked inhibitory effect on human leukaemia cells than on normal human cells, thus indicating a wider use for enzymes in cancer therapy. Studies of the effect of histidine concentration on cell growth, death, metabolism, protein composition, histidine uptake and utilization by cells were carried out. The medium and intracellular concentrations of histidine required for optimum cell growth and metabolism were much lower than for any other amino acid that has been studied. Also, there was very little evidence of cell death occurring in the absence of histidine. The results showed that cells in culture have a very low histidine requirement and that although the leukaemia cells were slightly more dependent upon histidine than normal cells the effect of histidine depletion is not critical enough to show much promise as a method of controlling leukaemia by therapeutic enzymes.

scholarly journals Liposomal delivery of methylphosphonate antisense oligodeoxynucleotides in chronic myelogenous leukemia [see comments]

Blood ◽  
1994 ◽  
Vol 84 (2) ◽  
pp. 601-607 ◽  
Author(s):  
AM Tari ◽  
SD Tucker ◽  
A Deisseroth ◽  
G Lopez-Berestein
Keyword(s):  
Growth Inhibition ◽  
Cell Lines ◽  
Chronic Myelogenous Leukemia ◽  
Fusion Gene ◽  
Hematologic Malignancy ◽  
Control Cell ◽  
Selective Inhibition ◽  
Inhibitory Effect ◽  
Myelogenous Leukemia ◽  
Ph Chromosome

Abstract Chronic myelogenous leukemia (CML) is a hematologic malignancy characterized by the presence of the Philadelphia (Ph) chromosome. Bcr- abl, the fusion gene associated with the Ph chromosome, expresses a p210bcr-abl protein that promotes a selective expansion of mature myeloid progenitor cells. Methylphosphonate (MP) oligodeoxynucleotides complementary to specific regions of the bcr-abl mRNA were incorporated in liposomes. We studied the effects of liposomal MP (L-MP) on the growth inhibition of CML-like cell lines. L-MP targeted to the breakpoint junctions of the bcr-abl mRNA inhibited the growth of CML cells. Fifty percent inhibition was achieved at approximately 1 mumol/L of L-MP oligonucleotide concentrations. The inhibitory effect was selective because growth inhibition was observed only with CML but not with control cell lines. Moreover, CML cell growth inhibition was dependent on the sequence of the MP oligodeoxynucleotides incorporated in the liposomes. The growth inhibition of CML cells by L-MP resulted from selective inhibition of the expression of the p210bcr-abl protein.

scholarly journals Selective Inhibition of Coxiella burnetii Replication by the Steroid Hormone Progesterone

2020 ◽  
Vol 88 (12) ◽  
Author(s):  
Zachary P. Howard ◽  
Anders Omsland
Keyword(s):  
Coxiella Burnetii ◽  
Efflux Pump ◽  
Q Fever ◽  
Steroid Hormone ◽  
Natural Infection ◽  
Placental Tissue ◽  
Selective Inhibition ◽  
Inhibitory Effect ◽  
Content Type ◽  
Direct Inhibitory Effect

ABSTRACT Coxiella burnetii is a zoonotic bacterial obligate intracellular parasite and the cause of query (Q) fever. During natural infection of female animals, C. burnetii shows tropism for the placenta and is associated with late-term abortion, at which time the pathogen titer in placental tissue can exceed one billion bacteria per gram. During later stages of pregnancy, placental trophoblasts serve as the major source of progesterone, a steroid hormone known to affect the replication of some pathogens. During infection of placenta-derived JEG-3 cells, C. burnetii showed sensitivity to progesterone but not the immediate precursor pregnenolone or estrogen, another major mammalian steroid hormone. Using host cell-free culture, progesterone was determined to have a direct inhibitory effect on C. burnetii replication. Synergy between the inhibitory effect of progesterone and the efflux pump inhibitors verapamil and 1-(1-naphthylmethyl)-piperazine is consistent with a role for efflux pumps in preventing progesterone-mediated inhibition of C. burnetii activity. The sensitivity of C. burnetii to progesterone, but not structurally related molecules, is consistent with the ability of progesterone to influence pathogen replication in progesterone-producing tissues.

scholarly journals Selective Inhibition of Platelet Agglutination and Aggregation by Aromatic Amidino Compounds

1977 ◽  
Author(s):  
J. D. Geratz ◽  
R. R. Tidwell ◽  
K. M. Brinkhous ◽  
S. F. Mohammad
Keyword(s):  
Selective Inhibition ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
The Other ◽  
Future Studies ◽  
Bovine Plasma ◽  
Inhibitory Activities ◽  
High Concentrations ◽  
Ristocetin Cofactor ◽  
Specific Inhibitors

A series of aromatic amidino compounds were investigated for their inhibitory effect on platelet agglutination and platelet aggregation. Agglutination of fresh or fixed human platelets was produced by bovine plasma or by human plasma in combination with ristocetin, while aggregation of fresh platelets was induced by ADP, thrombin or collagen. Highly effective inhibitors were found for both types of platelet clumping, but there was no parallelism between the inhibitory activities in the two test systems.5-(5-Amidino-2-benzimidazolyl)-2-(4-hydroxybenzene)benzimidazole suppressed agglutination exclusively. Pentamidine, on the other hand, strongly blocked the aggregation reactions, but did not interfere with agglutination, even at high concentrations. Compounds which inhibited aggregation also prevented the liberation of serotonin from the platelets.This investigation has led to the identification of new specific inhibitors of platelet agglutination and aggregation which can serve an important role in future studies of the two processes. The exact mode of interaction between ami dines and platelets is still being explored.. In the case of agglutination, inhibition most likely occurred at the level of binding of ristocetin cofactor to the platelet membrane. In the case of aggregation, however, interference could have taken place at the membranes or in the cytoplasm and could have been enzymatic or non-enzymatic in nature.

Inhibition of granulocyte phagocytosis of Candida albicans by amphotericin B

1978 ◽  
Vol 24 (4) ◽  
pp. 363-364 ◽  
Author(s):  
C. K. Chan ◽  
Edward Balish
Keyword(s):  
Candida Albicans ◽  
Amphotericin B ◽  
Phagocytic Activity ◽  
Inhibitory Effect ◽  
Marked Inhibitory Effect

Phagocytic activity of PMN's in five healthy and five burned patients were measured in vitro. Addition of 1 μg per millilitre of amphotericin B to the assay produced a marked inhibitory effect of the phagocytic activity of PMN against C. albicans.

Effect of dietary K+ and 75% nephrectomy on the morphology of principal cells in CCDs

1989 ◽  
Vol 256 (3) ◽  
pp. F387-F396
Author(s):  
R. K. Zalups
Keyword(s):  
Surface Density ◽  
Renal Mass ◽  
Basolateral Membrane ◽  
Inhibitory Effect ◽  
Potassium Depletion ◽  
Large Reduction ◽  
Factors Associated ◽  
Principal Cells ◽  
Marked Inhibitory Effect ◽  
Collecting Ducts

This investigation was carried out to determine the effect of potassium on the amplification of the basolateral membrane of principal cells in cortical collecting ducts (CCDs), which normally occurs after a large reduction of renal mass. Rats that underwent a 75% reduction of renal mass and were fed a diet deficient in potassium for 10 days after surgery had a lower concentration of potassium in the blood and excreted less potassium in the urine than either corresponding sham-operated (SO) rats or 75% nephrectomized (NPX) rats fed a normal-potassium diet. In the NPX rats fed the diet deficient in potassium, there was a marked inhibitory effect on the amplification of the basolateral membrane, which normally occurs in principal cells of CCDs after renal mass has been greatly reduced. In fact the surface density of the basolateral membrane, as well as the size of the principal cells in the animals fed the diet deficient in potassium were the same as those of principal cells in the SO rats fed the normal-potassium diet. Thus the present data show that the increase in cell size and the amplification of the basolateral membrane that occurs in principal cells after a 75% reduction of renal mass is inhibited by factors associated with potassium depletion.

Nitric oxide mediates the neural nonadrenergic, noncholinergic relaxation of pig tracheal smooth muscle

1992 ◽  
Vol 262 (4) ◽  
pp. L511-L514 ◽  
Author(s):  
M. S. Kannan ◽  
D. E. Johnson
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Electrical Field Stimulation ◽  
Selective Inhibition ◽  
Inhibitory Effect ◽  
Isometric Tension ◽  
Tracheal Smooth Muscle ◽  
Basal Tone ◽  
Dependent Inhibition ◽  
Nanc Relaxation

In pig tracheal smooth muscle, the isometric tension responses to electrical field stimulation (EFS) were studied after raising the tone with carbamylcholine chloride (carbachol). EFS induced frequency-dependent relaxations that were nonadrenergic, noncholinergic (NANC) in nature. Addition of NG-nitro-L-arginine (L-NOArg), an inhibitor of nitric oxide (NO) synthesis from L-arginine, resulted in concentration-dependent inhibition of the relaxation response to EFS. Pretreatment of the tissues with L-arginine (1 mM) prevented the inhibitory effect of L-NOArg on the EFS-induced relaxations at the frequencies studied. However, in the presence of D-arginine, EFS-induced relaxations were inhibited by L-NOArg. L-Arginine, D-arginine, and L-NOArg had no significant effects on basal tone of the muscle. In the presence of L-NOArg, vasoactive intestinal polypeptide (3 x 10(-7) M), the nicotinic agonist dimethylphenyl piperazinium bromide (100 microM), and isoproterenol (1 microM) relaxed carbachol-induced tone. The concentration-dependent selective inhibition of neural relaxation by L-NOArg and its reversal by L-arginine in a stereospecific manner are consistent with NO-mediated NANC relaxation of pig tracheal smooth muscle.

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