PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “BORIC ACID”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 955 records · Page 53Linked to original sources

[An improved trihydroxyindole method for the determination of urinary catecholamines].

Commercially available columns for ion exchange chromatography were used for the separation of catecholamines in urine. The estimation of catecholamines was performed fluorimetrically by a new trihydroxyindole method. The fluorescence of adrenaline or noradrenaline was enhanced, in comparison with other methods, by the combined application of boric acid, copper-ions, mercaptoethanol and final reacidification. The fluorophores are stable: The loss of fluorescence of adrenolutin amounted to 22% during 180 minutes, and there was no loss of noradrenolutin. For the differentiation of amines, adrenaline was oxidized at pH 2.85 and noradrenaline at pH 7. Precision, accuracy, sensitivity and specifity fulfilled the criteria of analysis. The normal values, determined in a collective of 17 healthy persons, were adrenaline (x +/- s) 44.8 +/- 16.9 nmol/24 h and noradrenaline (x +/- s) 224.0 +/- 68.0 nmol/24h. The simultaneous application of alpha-methyldopa (2 g/day) in 13 patients with primary hypertension did not disturb the fluorimetric estimation of catecholamines.

Chromatography, Ion Exchange↗

Dietary magnesium, manganese and boron affect the response of rats to high dietary aluminum.

Studies were done to ascertain whether dietary magnesium, manganese and boron affect the response of the rat to high dietary aluminum. Four factorially arranged experiments of 7 weeks duration were performed with weanling Sprague-Dawley male rats. The variables were the following supplements (microgram/g fresh diet): boron as boric acid, 0 and 3; aluminum as aluminum chloride, 0 and 1,000; and magnesium as magnesium acetate, 100 and 400 (experiments 1 and 4) or 100, 200 and 400 (experiments 2 and 3). In experiments 1 and 2, the diet was supplemented with 20 micrograms manganese/g as manganese acetate, in experiments 3 and 4 the supplement was 50 micrograms/g. High dietary aluminum seemed most toxic when dietary magnesium was low enough to cause a marked growth depression (100 micrograms/g). High dietary aluminum elevated the spleen weight/body weight and liver weight/body weight ratios in magnesium-deficient, but not in magnesium-adequate rats. High dietary aluminum depressed the concentrations of magnesium in bone more markedly in magnesium-deficient than adequate rats. On the other hand, aluminum seemed most toxic when dietary boron was not low. Aluminum more markedly depressed growth in boron-supplemented than boron-deprived rats. In the boron-deprived rats fed 400 micrograms magnesium/g of diet, high dietary aluminum (1,000 micrograms/g) apparently was beneficial, in experiments 2 and 3, hematocrit, and hemoglobin were actually normalized by high dietary aluminum. Plasma magnesium was significantly depressed by high dietary aluminum when the manganese supplement was 50 micrograms/g diet but not when it was 20 micrograms/g diet. On the other hand, growth was more markedly depressed by high dietary aluminum in boron-supplemented rats when the manganese supplement was 20 rather than 50 micrograms/g diet. The findings indicate that the response of rats to high dietary aluminum is influenced by magnesium, boron, and manganese nutriture.

Aluminum↗

[The refractory susceptibility in determination of sulfur in organic drugs using the Schoniger method].

Conventional methods of the determination of sulphur in organic drugs were studied (Schöniger method) and new methods developed. Emphasis was put on the disturbance effect of 5 elements, which often occur in the structure of organic drug compounds. It could be shown, that the disturbance effect of nitrogen and chlorine was overcome by the use of carbamide and ammonium carbonate in the absorption solution. The effect of fluorine was abolished by the use of boric acid and a special two-spiral technique of the analysis. Based on these studies concrete recommendations for the Schöniger method of sulphur determination in drugs of various composition of elements were given.

Amino Acids↗

[Immobilization of invertase in polyvinyl alcohol coatings].

A possibility of invertase immobilization in the polyvinyl alcohol coating formed directly on the electrode surface from water solution of polyvinyl alcohol and boric acid was being investigated. Conditions for obtaining the polymeric coating at the constant potential and at the constant current were compared. In order to obtain the polymeric coatings with a marked enzyme activity optimal conditions were found.

Electrochemistry↗

[Standardization of the complement fixation test (CFT) in brucellosis. III. The hemolytic system].

The purpose of this paper was to developed simple and accurate methods for standardization of the particular components of a hemolytic system and to choose optimal amounts of these components in CFT. On the basis of comparative studies and the data from literature the following procedure was chosen: 1. Sheep's blood was conserved with Alsever liquid and used after 5 days of stabilization. A 2% suspension of erythrocytes was standardized by centrifuging in calibrated test tubes at 1000 r for 10 min and spectrophotometrically, assuming the following criterion: the suspension of erythrocytes dissolved in distilled water at 1:10 ratio should show 0.500 extinction (E541), which corresponds to 5 X 10(8) erythrocytes in 1 cm3. 2. Lyophilized hemolysin was dissolved, conserved with glycerol and used after 5 days of stabilization. Hemolysin was titrated with 100% hemolysis in the presence of the excess of complement. The suspension of erythrocytes was sensitized with 5 units of hemolysin directly before using it. 3. Lyophilized complement (C) was dissolved, conserved with boric acid +K2SO4 containing liquid and used after 5 days of stabilization. Titration of C was done by 50% hemolysis; 3C'H50 was used in CFT. 4. A barbital buffer was used as diluent at pH 7.3-7.4, alternatively 0.85% NaCl with an addition of Ca and Mg at optimal concentration. The hemolytic system was incubated at 37 degrees C for 30 min.

Animals↗

Chronic suppurative otitis media in the Solomon Islands: a prospective, microbiological, audiometric and therapeutic survey.

Chronic suppurative otitis media affected 3.8% of 3500 Solomon Island children under 15 years (and 6.1% under 5 years) and was the sole cause of conductive hearing loss recorded in 265 children tested audiometrically. It was characterised by early onset (65% under 18 months) male preponderance and large central tubotympanic perforations. Measles, respiratory infections, swimming and malnutrition were identified as aetiological factors amenable to intervention. Proteus and pseudomonas were the principle aerobes isolated from ear pus and gentamicin the only antibiotic tested to be effective against them. However although a prospective therapeutic trial demonstrated a significantly improved outcome after aural toilet, no additional benefit was imparted by concurrent ototopical boric acid or aminoglycoside solution or oral antianaerobic clindamycin. Parental tuition in aural cleaning, avoidance of ear water entry, nose blowing and breathing will yield a good result in up to 60% of children in half of whom tympanic healing occurred.

Adolescent↗

[Enzymatic synthesis of 3,4-dihydroxyphenyl-L-alanine by free and immobilized Citrobacter freundii cells].

The Citrobacter freundii 62 cells immobilized in PAAG and possessing the tyrosine-phenol-lyase (TPL) activity catalyse the synthesis of 3,4-dihydroxyphenyl-L-alanine (DOPA) from pyrocatechol and ammonium pyruvate. The synthesis of DOPA was studied using both free and immobilized bacterial cells. When the concentration of pyrocatechol is over 0.1 M the TPL activity of the cells is inhibited. The concentration of pyrocatechol can be increased up to 0.3 M by using an equimolar mixture of pyrocatechol and boric acid. The addition of ascorbic acid as an antioxidant results in a lower TPL activity of both free and immobilized bacterial cells.

Acrylic Resins↗

[A survey on the current status and trends in bladder irrigation].

Questionnaires were sent to pharmacies and clinics in 592 Japanese hospitals from July to November, 1983 to investigate the use of bladder irrigation. The questionnaires were completed and returned by 418 hospitals, the rate of response being 70.8%. Fifty eight kinds of irrigants were prepared in hospital pharmacies and were reported to have been used in 1,171 patients. Of these irrigants, chlorhexidine gluconate accounted for 18.8%, Polymyxin B for 17.1%, normal saline for 13.3%, potassium permanganate for 6.9%, and boric acid for 5.7%. Chlorhexidine gluconate was usually used at a concentration of 0.02% (in 79% of the total use of the agent), Polymyxin B at 0.01%, 0.02% and 0.05%, potassium permanganate at 0.01% and 0.02% (in 73% of the total use), and acrinol at 0.01%, 0.05% and 0.1%. To questions about side effects, such as irritation, 65 hospitals answered that irritation had occurred. Irrigants were most frequently supplied to non-disposable 500 ml containers used exclusively for this purpose, 38% of all the hospitals using this method. Non-disposable 1 liter containers for exclusive use with bladder irrigants were used in 23% of the hospitals. Purified water was most frequently used to prepare the bladder irrigants (in 35% of hospitals) followed in descending order, by sterile purified water in 33%, and distilled water for injection in 26%. Water for irrigants was prepared at the hospital in 83% of the hospitals. The time of storage of the prepared bladder irrigants was mostly one week to one month, and was within one month in 78% of the hospitals. Seventeen percent of the hospitals answered that the preparation of bladder irrigants was a cause of overwork in their pharmacies. Irrigants against Pseudomonas infections were prepared separately in 40% of the hospitals, and there was no such regulation in 37%. Forty four agents were used to prepare such irrigants, and Polymyxin B accounted for 50%. The use of these agents significantly (P less than 0.001) differed between hospitals. Forty eight percent of the hospitals made special preparations for patients with clouded urine, and there was no such regulation in 46%. Thirty nine agents were used for this purpose. Polymyxin B was used in 30%, and chlorhexidine gluconate in 19%. The use of these agents differed significantly (P less than 0.001) between hospitals.(ABSTRACT TRUNCATED AT 400 WORDS)

Disinfection↗

Purification and properties of thiol beta-lactamase. A mutant of pBR322 beta-lactamase in which the active site serine has been replaced with cysteine.

The specifically mutated enzyme thiol beta-lactamase has been expressed in Escherichia coli by means of the trp promoter and purified to homogeneity. The gene for this enzyme results from a single base change N410 A----T in the gene of pBR322 RTEM beta-lactamase (EC 3.5.2.6, penicillinase, penicillin amido-beta-lactamhydrolase) which alters the codon for the active site Ser 70 to that for Cys. Precursor thiol beta-lactamase is processed to give the same NH2-terminal sequence as that for wild type enzyme. In contrast to the wild type enzyme, thiol beta-lactamase contains one free titratable thiol group/molecule. Thiol beta-lactamase catalyzes the hydrolysis of beta-lactams with a substrate specificity that is distinct from that of wild type enzyme. For benzyl-penicillin and ampicillin, the Km values are similar to wild type values although the kcat values are 1-2% that of wild type enzyme. For the cephalosporin nitrocefin, the Km is greater than 10-fold that of the wild type and the kcat is at least as large as the kcat for the wild type enzyme. Thiol beta-lactamase is different from wild type beta-lactamase in that it is not competitively inhibited by boric acid although a small degree of noncompetitive inhibition does occur. Whereas the circular dichroism spectra of both enzymes are nearly identical, thiol beta-lactamase at 40 degrees C is 3-fold more resistant to trypsin than is the wild type enzyme.

Amino Acid Sequence↗

Automated fluorometric analysis of calcium pantothenate in multivitamin preparations.

An automated fluorometric procedures is described for assaying calcium pantothenate in multivitamin preparations. Sample extracts containing calcium pantothenate are treated on-line with a slurry of magnesium trisilicate which removes any interfering riboflavin that may be present. The filtrate is resampled, mixed on-line with a slurry of Dowex 50W-X4 (H+) which removes any interfering beta-alanine that may be present, and dialyzed. Dialysates are hydrolyzed in an alkaline medium and reacted with a mixture of o-phthalaldehyde and 2-mercaptoethanol in boric acid solution. The fluorescence intensity due to the formation of a fluorogenic compound is measured at 455 nm after excitation at 350 nm. The procedure developed is capable of analyzing 20 samples/hr. Analytical data indicate that calcium pantothenate is assayed reliably both from real and synthetic multivitamin preparations. The mean recovery of calcium pantothenate added to sample solutions of tablet composites was 95.4%.

Autoanalysis↗

[Antibacterial therapy in treating the wound after animal bites].

A total of 150 patients with wounds due to animal bites were treated. The bacteriological analysis showed that during the first 24 hours after the bite the main microbes isolated from the wound contents were staphylococci and Coli bacteria. At later periods gramnegative microflora predominated. Prolonged washing of the wounds with furacin and sodium bicarbonate, 2 per cent boric acid after the wound dissection with establishing primary and secondary sutures, antibacterial therapy with semisynthetic penicillins and monomycin provided rapid healing of the wounds in 144 patients.

Animals↗

Colorimetric determination of clonidine.

2-(2,6-Dichloroanilino)-2-imidazoline hydrochloride (clonidine, Catapres) reacts with sodium nitroprusside in presence of sodium hydroxide, and on treatment with saturated boric acid it gives a violet colour measurable at 570 nm. The effect of pH, time, concentration of sodium nitroprusside and the type of acid used was studied. This colour is used to develop a colorimetric method for the determination of clonidine in its pharmaceutical preparations. The method can be adopted by quantities ranging from 200 to 1500 microgram with 100% +/- 1.68 accuracy.

Chemical Phenomena↗

Antidiuretic hormone excretion at high altitude.

Urinary excretion of electrolytes, creatinine, urea, and antidiuretic hormone--measured as arginine vasopressin (AVP) by radioimmunoassay--was investigated in eight Himalayan mountaineers during ascent on foot from 1900- 5400 m. Specimens were collected from each individual whenever urine was voided, preserved with 1% boric acid, and subsequently pooled to give samples representative of 24-h collections. AVP was found to be reasonably stable under simulated conditions of storage. In all subjects, the observed AVP excretion rates were mostly in the lower region of the normal range and there was generally no correlation with altitude, urine osmolality, electrolyte excretion, or occurrence of AMS symptoms--even in a fatal case of cerebral oedema. It is concluded that AVP does not play a primary role in the changes in fluid balance which accompany either acclimatization to high altitude or the onset of AMS.

Adult↗

Diaper dermatitis: current concepts.

Diaper dermatitis may result from prolonged skin contact with wetness and bacteria. Ammonia plays no apparent role in the generation of diaper dermatitis. Candida albicans frequently contaminates a diaper dermatitis and should be considered present in any diaper dermatitis and should be considered present in any diaper dermatitis known to be present for longer than three days. Topical fluorinated glucocorteroids, boric acid, and mercury-containing preparations should be avoided in the diaper area because of their toxicity.

Ammonia↗

Safety and toleration of oxymetazoline ophthalmic solution.

Two studies were carried out in volunteers without any abnormal ocular conditions to assess the effects and safety of an ophthalmic preparation of oxymetazoline (0.025%). In the first study in which oxymetazoline was compared with placebo and phenylephrine, the results of infra-red electronic pupillography showed that oxymetazoline in therapeutic doses had no effect on pupil size or near point recession. The second study, which was a double-blind forced choice comparison of two different formulations against placebo and 1% naphazoline, showed from assessments of the degree of ocular discomfort and hyperaemia that oxymetazoline was well tolerated and the subjects preferred oxymetazoline in a boric acid rather than in a phosphate solution.

Accommodation, Ocular↗

[Incidence of hypersensitivity to antibiotics and preservatives in eye drops].

PURPOSE: To elaborate a set of contact allergens present in eye drops which could precipitate allergic conjunctivitis. Such set has not been yet described in literature. METHODS: Basing on the most frequently used preparations, a set of 15 different substances: drugs and preservatives, was prepared to test the patients. RESULTS: Among the 97 persons who underwent the testing, positive results were observed in 35.5%. The hypersensitivity was found for 11 of the allergens, the most often for neomycin, gentamycin, merthiolate, benzalkonium chloride, and then consecutively for kanamycin, sulfathiazole, oxytetracycline, chloramphenicol, penicillin, boric acid and parabens.

Adolescent↗

The effects of boron on the electron paramagnetic resonance spectra of alanine irradiated with thermal neutrons.

The effects of boric acid admixture on the intensity and line structure of EPR spectra of free radicals produced in alanine by thermal neutrons are presented. The EPR signal enhancement, up to a factor of 40 depending on the boron concentration, is related to additional energy deposition in alanine crystals by the disintegration products resulting from the capture of a thermal neutron by boron, 10B(n,alpha)7Li. The changes in the shape of the EPR spectra observed by changing the microwave power are due to the differences in the microwave power saturation of the free radicals produced by a low-LET radiation and those produced by the high-LET components of the radiation after the neutron capture reaction.

Alanine↗