Presence Of Sodium Fluoride Research Articles

Adenyl cyclase and cyclic AMP (cAMP) in acute experimental pancreatitis: Biochemical and histochemical studies

The level of adenosine 3′:5′-cyclic monophosphate (cAMP) and the activity of adenyl cyclase were studied in the pancreas under normal conditions and during acute hemorrhagic pancreatitis induced by intraductal injection of fresh trypsin-bile-blood mixture. In addition, the adenyl cyclase was localized histochemically in the pancreas. Basal cAMP concentration and adenyl cyclase activity were 0.88 ± 0.11 pmoles/mg wet tissue and 3.39 ± 0.21 pmoles/mg protein/min, respectively. The acute pancreatitis drastically reduced the adenyl cyclase activity at 15 minutes to 1.66 ± 0.54 pmoles/mg protein/min, and totally suppressed adenyl cyclase activity at 30 minutes after the onset of pancreatitis without affecting cAMP levels. The presence of sodium fluoride in the incubation medium prolonged the enzyme activity up to 45 minutes. The progressive disappearance of adenyl cyclase activity presumably resulted from the destruction of cellular integrity caused by autodigestion by the active proteolytic enzymes released during pancreatitis.

The evaporation and high-temperature reactions of elements and their compounds in a d. c. carbon arc for spectrochemical analysis

A study has been made of the high-temperature reactions taking place in the graphite matrix of a d. c. carbon arc. A special evaporator was used for controlled heating of samples. Volatilisations were investigated spectrographically, and X-ray diffraction was used for detection of any new phases formed. The presence of sodium fluoride or chloride was found to enhance the volatilisation of the elements investigated, but no evidence was found for formation of their fluorides or chlorides.

Renal Receptors for Calcitonin: Coordinate Occurrence with Calcitonin-Activated Adenylate Cyclase

High affinity binding of 125I-labeled salmon calcitonin ([125I]SCT) and calcitonin-activated adenylate cyclase were detectable in renal plasma membranes from the rat. Addition of 5'-guanylyl-imidodiphosphate lowered the threshold for enzyme activation by peptide hormones. Renal plasma membranes from man, dog and cow contained little or no calcitonin-sensitive adenylate cyclase and showed no high affinity binding of [125I]SCT. High affinity binding sites were distributed during membrane fractionation in fractions where the specific activity of hormone-sensitive adenylate cyclase was greatest. Calcitonin binding and activation of the adenylate cyclase enzyme occurred at similar hormone concentrations. The relative potencies of calcitonin analogues were similar whether measured by competition for high affinity binding sites or by effect on adenylate cyclase. Low concentrations of Lubrol-PX, a nonionic detergent, did not affect catalytic function of the enzyme determined in the presence of sodium fluoride but caused parallel loss of high affinity [125I]SCT binding and hormonal sensitivity of the enzyme. This observation provided further evidence that interaction of calcitonin with specific receptors (identified with [125I]SCT binding) is essential for calcitonin activation of adenylate cyclase, but showed that catalytic activity of enzyme does not require functioning hormone receptors.

ChemInform Abstract: KINETICS AND MECHANISM OF THE REDUCTION OF SELENIUM(IV) BY IRON(II) IN PRESENCE OF SODIUM FLUORIDE

AbstractIn schwach saurer Lösung verläuft die Reduktion von Se(IV) durch Fe(II) nach 1. Ordnung hinsichtlich der Fe(II)‐Konzentration und unabhängig von der Se(IV)‐Konzentration.

Studies on cellular adhesion in tissue culture: XIIA. Some effects of prostaglandins and cyclic nucleotides

The effects of cyclic nucleotides, and physiologically related substances, on the initial adhesion of three groups of cells to protein covered plastic surfaces in vitro, was studied over periods of up to 2 h. The rate of adhesion of Ehrlich ascites tumour (EAT) cells was decreased in the presence of prostaglandin F 2α and dibutyryl cyclic AMP; possibly decreased by PGE 1; increased in the presence of sodium fluoride, and unaffected by PGF 2β. Trypsinized EAT cells showed no adhesion-response to PGE 1 or PGF 2β, and generally a lesser degree of response to the other reagents than non-trypsinized EAT cells. L929 cells, following trypsin-treatment, showed a significant decrease in adhesion rate, only on culture in the presence of PGF 2α. The inhibition of initial adhesion in the responding cells, may be correlated with the assays of others and interpreted to indicate that increase in intracellular cyclic nucleotides is associated with decreased initial cell adhesion. The failure of the L929 to respond to at least some of the reagents is possibly partly due to their prior incubation with trypsin.

Fluorinations in the presence of sodium fluoride. Preparation of tetrakis(difluoramino)methane

Fluorinations in the presence of sodium fluoride. Preparation of tetrakis(difluoramino)methane

Acid phosphatases of the rat testis in experimental conditions.

ABSTRACT Quantitation of four different testicular acid phosphatases was carried out during pubertal maturation as well as after cryptorchidism and cadmium chloride treatment. The assay conditions were based on differential substrate and modifier characteristics and the results were correlated to the histological appearance of the testis. Enzyme I activity with naphthol AS-BI phosphate as substrate showed the highest activities in the prepubertal testis and no appreciable changes took place after cryptorchidism. Enzyme II activity with α-naphthyl phosphate as substrate was also high in the prepubertal testis and an increase occurred after cryptorchidism. The results are in agreement with a preferentially interstitial origin of enzymes I and II. Enzyme III was quantified using β-naphthyl phosphate as substrate with sodium fluoride (5 mm) to inactivate enzymes I and II. A moderate increase of this enzyme activity during the pubertal development and a gradual decrease after cryptorchidism suggested tubular origin. Enzyme IV activity was followed using p-nitrophenyl phosphate as substrate in the presence of sodium fluoride (5 mm) and Co2+ (5 mm) as a specific activator. A rapid potentiation of activity took place during pubertal development and a precipitous decrease after cryptorchidism. The results indicate a tubular origin of enzyme IV, which was confirmed by fractionation studies. Cadmium chloride treatment caused a rapid decrease of all enzyme activities, but the decline was more abrupt for the tubular enzymes III and IV. The results indicate that the specific testicular acid phosphatase IV may be useful in studies on the hormonal control of spermatogenesis.

Kinetics and mechanism of the reduction of selenium (IV) by iron (II) in presence of sodium fluoride

The reduction of selenium (IV) by iron (II) in presence of sodium fluoride has been kinetically studied in presence of slightly acidic medium. The reaction rate is first order with respect to iron (II) but is independent of Se(IV). It is also directly proportional to fluoride concentration, but acid has a retarding effect. The reaction rate increases with increasing ionic strength, but decreases with increasing di-electric constant of the medium. A suitable mechanism has been proposed leading to a rate expression.

Effect of sodium fluoride on protein synthesis in HeLa cells: Inhibition of ribosome dissociation

Incubation of HeLa cells with sodium fluoride results in inhibition of protein synthesis, disaggregation of polyribosomes, accumulation of 80 s ribosomes and decrease of free ribosomal subunits. Part of the messenger released from polyribosomes by fluoride is recovered in a particle sedimenting at 95 s. The decrease of ribosomal subunits occurs only in cells which are active in protein synthesis and appears to be due to the block of ribosome dissociation which in turn prevents ribosome recycling. The analysis of small ribosomal subunits “chasing” into ribosomes, when the free ribosomal subunit pool is depleted in the presence of sodium fluoride, shows no evidence of selectivity between relatively new and old particles in this conversion. After the removal of sodium fluoride, the normal level of free ribosomal subunits is restored at the expense of a random dissociation of ribosomes. The results are consistent with a model of ribosome function in which cyclic dissociation into free ribosomal subunits takes place.

Maintenance of polar auxin transport in Zea coleoptiles by anaerobic metabolism

The basipetal movement of IAA in 5-mm Zea coleoptile segments is drastically reduced under anaerobic conditions, but it remains greater than acropetal movement which is closely similar in the presence and absence of oxygen. The polarity of IAA movement has thus been confirmed in Zea coleoptile segments which have been deprived of oxygen. This net polar flux is dependent upon anaerobic metabolism since it is abolished in the presence of the metabolic inhibitiors sodium fluoride and iodoacetic acid.Acropetal movement of IAA is unaffected by the presence of sodium fluoride in air or anaerobic conditions. Uptake of IAA from a basal donor is not affected by sodium fluoride in air, but under anaerobic conditions the inhibitor decreased uptake by approximately 13%.Under anaerobic conditions both inhibitors reduce basipetal movement of IAA to the level of acropetal movement, and both decrease the total uptake of IAA from an apical donor by up to 30-45%. Under aerobic conditions sodium fluoride has no marked effect upon either the uptake of IAA from an apical donor or the basipetal movement of IAA by the segments. On the other hand, iodoacetic acid greatly decreased the uptake of IAA by the segments in air, but the same fraction of the total IAA taken up was recovered in the receiving block in the presence and absence of the inhibitor.

The growth of Lancefield Group D streptococci in the presence of sodium fluoride

Five strains of Lancefield Group D streptococci were grown for 4 days in 0.002M fluoride, then for 4 days in 0.01M, 0.033M and 0.10 fluoride successively. Such cultures were termed “fluoride-trained”. These “trained” cultures grew more successfully in high fluoride concentrations than control cultures of the same strains, but grew less densely than the controls in the absence of fluoride. The ability to resist fluoride-inhibition was lost when the “trained” cultures were grown for 2–3 days in fluoride-free media. No significant change in the routine identification tests was observed in the “trained” culture. The possible interpretations of these experiments in terms of adaptation and of selection of mutants is discussed.

Active transport of epinephrine into blood platelets.

An active transport of serotonin was demonstrated in a previous report from this laboratory on rabbit blood platelets. Epinephrine is known to be taken up by the blood platelets as serotonin when the cells are suspended in plasma. In this paper evidence of an active transport of epinephrine is presented. The absorption of this amine is the movement into the cell against a concentration gradient. Epinephrine added to the suspending medium accumulated in the cells, after 1 hour's incubation at 37°C, when glucose or its metabolites were present. The concentration of the amine rose to 1 or 2 µg from about 0.005 µg/mg dry weight of platelets. Glucose, pyruvate, acetate, α-ketoglutarate and fumarate were the effective stimulators. The effect of glucose was diminished by the presence of sodium fluoride, iodoacetate, 2,4-dinitrophenol and reserpine. Competitive inhibitions of the active transport by aromatic compounds containing ethylamine groups might suggest the participation of the amine group of epinephrine in its transport. In contrast, serotonin transport was inhibited by a 5-hydroxyindol compound.

The use of cobalt acetate in the histochemical technic for acid phosphatase.

The staining technic for the visualization of acid phosphatase is based on the finding that when sections of tissue are placed in a medium containing a phosphone ester, the sites of the enzymatic liberation of phosphate could he determined if lead ions are present to precipitate the phosphate as it is formed. fh deposit of lead phosphate could be converted to an easily visualized black pre(ipitate of lead sulfide (Oomori, 1941). This note describes a technic based on the same principle, but replacing lead by (ol)alt, which precipitates a blue insoluble orthophosphate at loci of phosphatase action. Acetone fixed tissues (1 mm. thick) were washed with distilled water and passed to a I % (obalt a(etate solution for 10 minutes. The tissues were then placed for 12 hours iii it medium (pH 6.0-6.5) containing equal parts 2 % cobalt acetate “stock” solution and 0.2 % sodium-$-glycerophosphate, freshly prepared. The zones where the phosphatase is concentrated develop a deep blue color. It is not possible to use the cobalt acetate technic at pH 5.0 (which is the optimum pH of acid phosphatase) because at this pH precipitation of phosphate is incomplete. Ilowever, cobalt acetate presents the advantage of not precipitating with the phosphoric esters and proteins. For microscopic observation frozen sections 20 to 40 /2 thick were incubated 3 to 6 hours in the substrate medium, rinsed with distilled water, and immersed 15 minutes in either of the two following solutions, prepared just before using: a) Ammonium sulfide-alcohol (1 cc. of concentrated ammonium sulfide in 50 cc. of 70 % alcohol), b) H2S water prepared by bubbling H2S through distilled water. Wash with 70 % alcohol or distilled water respectively, dehyd rate in alcohol and mount in Euparal. The deposit of cobalt phosphate is thus converted to the more easily visualized black precipitate of cobalt sulfide. Simultaneously a control is run by treating tissue with cobalt acetate only, to (heck preformed cobalt-positive substances. Typical blue precipitates are obtained with the root tips of A ilium cepa, rootlets and cotyledons of Pisum sativum, liver and the gray substance of the guinea pig’s spinal cord, among others. Phosphate liberation is inhibited in the presence of sodium fluoride (M/10), by heating of the tissue to 95#{176}C for 30 minutes, by fixation in 10% formalin or by sulfuric acid (0.25 N) treatment for two hours. The enzyme is not inhibited in the presence of iodoacetate (M/ 100) or by exposure of the acetone fixed tissues to 2 citric or acetic acid for 2 to 6 hours. Fixation in Carnoy’s fluid (2#{176}-5#{176}C.)

Nitration of Starches with Nitrogen Pentoxide in Presence of Sodium Fluoride

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitration of Starches with Nitrogen Pentoxide in Presence of Sodium FluorideG. V. Caesar and Max GoldfrankCite this: J. Am. Chem. Soc. 1946, 68, 3, 372–375Publication Date (Print):March 1, 1946Publication History Published online1 May 2002Published inissue 1 March 1946https://doi.org/10.1021/ja01207a007RIGHTS & PERMISSIONSArticle Views225Altmetric-Citations35LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (513 KB) Get e-Alerts Get e-Alerts

The Determination of Sodium Carbonate in the Presence of Sodium Fluoride.

The Determination of Sodium Carbonate in the Presence of Sodium Fluoride.