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At least 19 recordsLinked to original sources
PubMed1975

[Phosphoric acid ester preparations used in cattle, swine and sheep with special reference to cholinesterase activity. 3. Use of phosphoric acid ester preparations and their effect on acetylcholinesterase activity in swine].

The use of organophosphorus preparations in the treatment of ectoparasites and endoparasites of pigs is discussed. Treatment of 43 store pigs with preparations produced in the German Democratic Republic by washing and by the pour-on method resulted in considerable inactivation of acetylcholinesterase, which implies good systemic action. Overdosage increased this effect, but without producing signs of toxicity. The oral dosages for pigs cited in the literature were confirmed. Repeated treatment was recommended for the best results, as pigs rapidly break down the preparations. It is necessary to take into account adverse effects of oral administration on palatability of the ration and on weight gain. Addition of a preparation to a batch of food for a group of pigs is likely to be less successful than individual dosing, which is the best method for sows.

Acetylcholinesterase↗
PubMed1975

[Phosphoric acid ester preparations used in cattle, swine and sheep with special reference to cholinesterase activity. 4. Use of phosphoric acid esters and their effect on acetylcholinesterase activity in sheep].

The use of organophosphorus preparations for the control of ectoparasites and endoparasites of sheep, particularly systemic application, is discussed. Experiments on 13 groups of sheep with five preparations produced in the German Democratic Republic in various formulations and concentrations showed that external application had good contact activity, but little was absorbed. Acetylcholinesterase activity was not inhibited, except by pour-on application of doses several times the normal dose. The preparations were arranged in order of cholinesterase inhibition. In contrast to cattle, diminished cholinesterase activity was unreliable as in indicator of systemic toxicity of organophosphorus preparations in sheep.

Acetylcholinesterase↗
PubMed1991

Effects of phosphoric acid and tannic acid on dentine collagen.

We examined the effects of phosphoric acid, the most common enamel etchant in composite resin therapy, on dentine collagen. Dentine collagen pretreated with 7M phosphoric acid was shown to be more susceptible to trypsin digestion than untreated collagen. This susceptibility increased with increasing duration of exposure to the acid. The results indicate that phosphoric acid induces a conformational change in dentine collagen (denaturation or perturbation) similar to that observed with 0.39 M HCl, which has a similar pH value (0.65). However, phosphoric acid-pretreated dentine collagen, when treated with tannic acid for 2 h, became as resistant to tryptic digestion as intact dentine collagen. The present results suggest that tannic acid may work as a dentine conditioner in composite resin therapy, in view of the fact that phosphoric acid etchant is applied, either deliberately or inadvertently, to dentine, and would thus induce denaturation or perturbation of collagen.

Animals↗
PubMed1975

The use of 50 per cent phosphoric acid as an etching agent in orthodontics: a rational approach.

The chemical treatment of enamel surfaces is an approach used in obtaining increased adhesion of dental materials to tooth surfaces. One of the conditioning solutions extensively used prior to the direct bonding of orthodontic attachments is a 50 per cent phosphoric acid solution. The object of this investigation was to study the effect of various concentrations of phosphoric acid on the bond strength of an epoxy adhesive formulation developed for the direct bonding of orthodontic attachments. Furthermore, an attempt was made to quantitate the etching action of the phosphoric acid solutions by determining the depth of etch on polished enamel surfaces and recording the surface profiles of etched enamel surfaces by means of a surface-roughness measuring instrument. The use of 50 per cent phosphoric acid solution as a conditioning agent prior to the use of the epoxy adhesive formulation is advocated. The rationale supporting this recommendation includes (1) the bond strength of the epoxy adhesive system to enamel surfaces etched with 50 per cent H3PO4 is not significantly improved by the use of phosphoric acid at any other concentration; (2) the depth of etch obtained with 50 per cent H3PO4 is less than that observed with H3PO4 solution at concentrations which produce comparable bond strengths; (3) the surface roughness of enamel surfaces etched with 50 per cent H3PO4 is greater than that obtained with more dilute acid solutions. The optimal phosphoric acid concentration should be determined for each adhesive system.

Dental Bonding↗
PubMed1975

Effect of carbonated beverages and of an antiemetic containing carbohydrate and phosphoric acid on riboflavin bioavailability and salicylamide biotransformation in humans.

Two carbohydrate-phosphoric acid solutions, one a widely used beverage (Solution C) and the other a pharmaceutical product used as an antiemetic (Solution E), administered together with riboflavin-5'-phosphate or salicylamide to healthy human adults, significantly increased the bioavailability of riboflavin and appreciably altered the metabolic fate of salicylamide (increased conversion to the sulfate and decreased formation of the glucuronide). A beverage containing phosphoric acid but no carbohydrates (Solution T) also increased the bioavailability of riboflavin but not as much as Solution C. These effects are attributed to a decrease of the gastric emptying rate caused by carbohydrates and phosphoric acid, consistent with the empirical use of Solution C syrup and Solution E as antinauseants and antiemetics. The results demonstrate also that the choice of beverage to be taken with medication can affect the bioavailability and/or metabolic fate of medicinals with saturable absorption and/or biotransformation characteristics.

Adult↗
PubMed1992

Effect of dietary phosphoric acid supplementation on acid-base balance and mineral and bone metabolism in adult cats.

Experimental evidence indicates that maintenance of urinary pH < or = 6.4 is the single most effective means of preventing feline struvite crystalluria or urolithiasis of noninfectious causes. This may be accomplished by dietary acidification, but must be moderated to avoid potential adverse effects of excessive acidification, including bone demineralization, negative calcium balance, potassium depletion, and renal disease. Effects of chronic dietary phosphoric acid supplementation on acid-base balance and on mineral and bone metabolism were investigated in adult, domestic cats. One group of 6 cats was fed a basal, naturally acidifying diet without added acidifiers, and another group of 6 cats was fed 1.7% dietary phosphoric acid. Changes observed during 12 months of study included development of noncompensated metabolic acidosis, increased urinary calcium excretion, and lower but positive calcium balance in cats of both groups. Urinary pH decreased in cats of both groups, but was significantly (P < 0.05) and consistently maintained < or = 6.4 in cats given dietary phosphoric acid. Urinary phosphorus excretion increased in cats of both groups, but was significantly (P < 0.05) greater in phosphoric acid-supplemented cats, leading to lower overall phosphorus balance as well. Potassium balance decreased in cats of both groups, but was only transiently negative in the phosphoric acid-supplemented cats midway through the study, and normalized at positive values thereafter. Plasma taurine concentration was not affected by dietary acidification, and remained well within the acceptable reference range for taurine metabolism. Double labeling of bone in vivo with fluorescent markers was followed by bone biopsy and histomorphometric measurement of several static and dynamic variables of bone formation. Overall indices of bone formation decreased in cats of both groups with age and confinement, but were not affected by dietary phosphoric acid supplementation. Dietary supplementation with phosphoric acid used as the principal inorganic P source to achieve moderate and stable degree of urinary acidification, did not appear over the course of 1 year, to have induced adverse effects on mineral, bone, or taurine balance in these adult domestic cats.

Acid-Base Equilibrium↗
PubMed1992

Kinetics of hydroxyapatite dissolution in acetic, lactic, and phosphoric acid solutions.

The present study was undertaken in an attempt to relate the kinetics of hydroxyapatite dissolution to solution parameters, under experimental conditions relevant to the dental caries process. Thus, the dissolution of hydroxyapatite was studied in acetic, lactic, and dilute phosphoric acid solutions having initial pH values from 4 to 6. Rates of dissolution and the corresponding degree of saturation with respect to hydroxyapatite were determined at various times throughout the dissolution process. Rates of dissolution of all solutions were found to decrease with increasing degree of solution saturation and were greater in solutions with lower initial values of pH. However, rates of dissolution in partially saturated phosphoric acid solutions (without added organic acid) were at least one order of magnitude lower than those observed in the organic acid buffers with the same initial pH, over the same range of saturation values. The data obtained are consistent with a surface-controlled dissolution model in which the rate of dissolution is dependent upon the degree of saturation and the sum of the activities of the acidic species in solution, i.e., phosphoric and organic acids. These results suggest that in order to assess the cariogenic potential of a given medium (e.g., plaque fluid), one must determine both the degree of saturation with respect to the dissolving mineral and the activities of acidic species in solution.

Acetates↗
PubMed1979

Detection of DNA in mammalian tissues following removal of RNA with cold phosphoric acid.

The paper deals with the staining of nuclei in mammalian tissue sections with night blue, belonging to diphenylnaphthylmethane group and is devoid of any primary amino group in its molecules but is provided with a secondary amino group and tertiary amino groups. Staining of the DNA-phosphate groups with an aqueous solution of night blue depends upon selective removal of RNA from formalin-fixed mammalian tissues by the use of cold concentrated phosphoric acid for 20 min or 75% phosphoric acid in the cold for 2 h. Moreover, sections from which RNA has been extracted can be hydrolysed in 6N HCl at room temperature for 15 min and then can be stained with the aqueous solution of the dye. Sections of tissues after only acid hydrolysis and staining also reveal very satisfactory staining of the nuclei. Possible mechanism of staining has been suggested.

1-Naphthylamine↗
PubMed1992

Phosphoric acid as a dentin etchant.

This study determined the effect of phosphoric acid (H3PO4) application to dentin on the shear bond strength (SBS) and microleakage of an experimental bonding system. Thirty human maxillary permanent first and second molars were used for the SBS evaluation. In 15 of the teeth the Dentin Conditioner was applied to dentin for 30 seconds (A), while in the remaining 15 teeth the smear layer was removed by the application of a 37% H3PO4 gel for 20 seconds (B). The Primers 1 and 2 were mixed and applied to the conditioned dentin followed by the application of the Dentin Bonding Resin prior to the placement in three increments of the Bisfil-M composite. The specimens were stored in physiological saline at 37 degrees C for 24 hours prior to applying a shear load at a crosshead speed of 0.5 mm. inch-1 in an Instron machine. Shear bond strengths were expressed in MPa. Circular Class V preparations were made on the roots of 30 maxillary permanent canines, 15 restored using the Dentin Conditioner (C) and 15 by removing the smear layer with the H3PO4 gel (D). Microleakage of the restorations was determined quantitatively by means of a spectrophotometric method. The quantitative microleakage was expressed as microgram dye/restoration. The data were analyzed by the Student t-test. The following results were obtained: A: 14.2 +/- 2.2 MPa; B: 7.2 +/- 4.2 MPa; C: 30.0 +/- 28.6 micrograms dye/restoration; (D) 10.3 +/- 8.2 micrograms dye/restoration. Removing the smear layer with H3PO4 reduced the SBS to dentin but decreased the quantitative microleakage significantly.

Acid Etching, Dental↗
PubMed1977

[Chronic broncopneumopathy and pneumoconiosis in workers employed in phosphoric acid production (author's transl)].

Thirty-five subjects employed in a phosphoric acid producing plant were studied by the authors. The investigation included: history, according to the C.E.C.A. questionnaire for chronic bronchitis and emphysema; physical examination, chest X-ray spirometry and lung diffusing capacity for carbon monoxide by the steady state method (DLCOSS). High prevalence of chronic bronchitis (45.7%), obstructive spirometric impairment (37.1%), and decreased values of DlcoSS (31.4%) were detected. Two subjects were found to be affected with p 1/0 and 7 with p 0/1 pneumoconiosis. Such findings were significantly related to the lenght of working activity as well as to dust and gaseous fluoride (hydrofluoric acid, hexafluorosilicic acid and silicon tetrafluoride) exposure.

Adult↗
PubMed1978

Pulpal response to the application of phosphoric acid to dentin.

Experimental cavities were prepared in forty-six clinically intact premolars of young individuals to evaluate the biologic effects of 50 per cent phosphoric acid etchant containing 7 percent zinc oxide by weight. The experimental periods ranged from 30 minutes to 150 days. The remaining dentin thickness varied from 1.8 to 3.5 mm. The teeth treated with the acid showed no more than a moderate pulpal response at the varying time periods. All of the acid-treated teeth demonstrated pulpal imflammation in the absence of clinical pain. Acid etchants should not be used on exposed or unprotected dentin surfaces.

Acid Etching, Dental↗
PubMed1992

The effects of different phosphoric acid concentrations on surface enamel.

The purpose of this study was to evaluate the effects of different acid concentrations on the enamel surface morphology. The buccal surfaces of 25 extracted premolars from young patients were etched with 40%, 20%, 10%, 5%, and 2% phosphoric acid solutions for 60 seconds. The specimens were examined with a scanning electron microscope in the occlusal, central, and cervical regions. A great variation of the etching patterns was observed in almost all test groups. The extent of the appearance of prism outlines was smaller in the cervical region and at lower acid concentrations. The advantages and disadvantages of the use of lower concentrated acids are discussed.

Acid Etching, Dental↗
PubMed1979

Tensile strength of the bond between resin to enamel etched with phosphoric acid containing fluoride.

The tensile bond strength of Epoxylite 9075 and Enamelite to enamel treated with NaF and SnF2, at two concentrations, in the etching acid (H3PO4) was determined. The average fracture stress of those samples in which fracture occurred in the resin only, may be considered as the tensile strength of the resin, 69.8 +/- 5.6 kg/cm2. The mean fracture stresses of the Epoxy 9075 systems etched with pure phosphoric acid or with acid solutions containing 0.5% F salts were significantly higher than those treated with acid solutions containing 2% F salts. Incorporation of NaF or SnF2 in the etching solutions highly increased the fluoride concentration of enamel. The fluoride increase dependend on the fluoride concentration of the etching solution and was greater for NaF than SnF2.

Acid Etching, Dental↗
PubMed1979

Blood phosphorus levels of laying hens at various time intervals after dosing with phosphoric acid.

Two experiments were conducted to study the pattern of change in serum inorganic phosphorus level in laying hens fed a diet containing 0.30% total phosphorus after dosing with a known amount of phosphorus. Serum phosphorus level of undosed hens was 2.5 mg/100 ml at oviposition in both experiments. After dosing with 100 mg of phosphorus in 10 ml of a phosphoric acid solution, serum phosphorus level increased sharply and reached a peak of about 7.0 mg/100 ml between 30 and 60 minutes in experiment 2. After the peak the elevated level of serum phosphorus decreased logarithmically until 5 to 6 hours after dosing and eventually decreased to 2.5 mg/100 ml which was the serum phosphorus level of undosed hens in experiment 1. The half-life of the elevated portion of serum phosphorus due to the dosing was about 100 minutes.

Animals↗
PubMed1977

[Possible combinations of antidotal therapy in rats following intoxication with phosphoric acid esters (author's transl)].

In order to improve or supplement the currently used therapy of poisoning with phosphoric acid esters, a protein free extract from calf blood containing low-molecular subtances (Actihaemyl, Solcseryl) has been tested in female Wistar rats. After poisoning with paraoxon, DFP and soman, a combination of Solcoseryl, Toxogonin and atropine sulfate prolonged the time until exitus, improved the overall rate of survival and considerably shortened the phase of regeneration of the experimental animals even when they had been intoxicated with high doses of poison.

Actihaemyl↗
PubMed1977

Collaborative study of a spectrofluorometric assay for Rauwolfia serpentina tablets and powdered root, using a vanadium pentoxide-phosphoric acid determinative step.

Reserpine-rescinnamine group alkaloids are extracted from Rauwolfia serpentina preparations into dimethylsulfoxide (DMSO)-methanol and diluted with 0.5N H2SO4. The chloroform extract of this solution is passed through a 0.1N NaOH-Celite column and then through a silica gel column. The weakly basic alkaloids trapped on the latter column are eluted with chloroform-methanol; a portion of the eluate is treated with a vanadium pentoxide-phosphoric acid solution, and the reserpine-rescinnamine content is determined by measuring the intensity of the resulting fluorescence. The following means and standard deviations (11 collaborators) were obtained for the determination of reserpine-rescinnamine group alkaloids in 4 samples of Rauwolfia serpentina (NF reference powder, 100 and 50 mg commercial tablets, and 45 mg synthetic tablet formation): 0.173%, 0.0050; 0.128%, 0.0030; 0.150%, 0.0069; and 0.142%, 0.0032; respectively. The method has been adopted as official first action.

Indicators and Reagents↗
PubMed1979

[Permeability of N,N-bis(2-chloroethyl)-diamido-phosphoric-acid into tumor cells (author's transl)].

The uptake of tritiated N,N-bis(2-chloroethyl)-diamido-phosphoric-acid into Ehrlich-Ascites-Tumor cells of mice was studied by means of the siliconoil-filtration technique. At 10 mM concentration no permeation of the metabolite into the tumor cells could be found within 5 min at 1 degrees C, while its congenors cyclophosphamide and 4-hydroperoxycyclophosphamide (1 mM) were shown to permeate into the cells very easily reaching saturation values. Thus lack of permeation into tumor cells of N,N-bis(2-chloroethyl)-diamidophosphoric-acid seems to be the reason for the poor cytotoxic activity of this metabolite of cyclophosphamide.

Animals↗