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At least 181 records · Page 10Linked to original sources
PubMed1996

Accumulation of boron in malignant and normal cells incubated in vitro with boronophenylalanine, mercaptoborane or boric acid.

The short (< 10 microns) ranges of alpha and 7Li particles produced during boron neutron capture therapy (BNCT) make the partitioning of the boronated drug within and without the cell of critical importance. The evaluation of the potential usefulness of a boron-containing substance for BNCT requires information about its intracellular accumulation. In the present report, an in vitro method is described for direct measurement of intracellular boron based on rapid centrifugation of cells through a layer of mineral oil and silicon oil to strip away extracellular growth medium. The intracellular concentrations of boronophenylalanine (BPA), mercaptoborane (BSH) and horic acid in malignant cells and in normal cells have been compared. The accumulation ratio is defined as the ratio of the intracellular to the extracellular boron concentration. Boric acid showed an accumulation ratio of 1 while the ratios for BSH and BPA were dependent on cell type and tended to be greater for BPA than for BSH in malignant but not in normal cells.

Animals↗
PubMed1980

An improved method for determination of plasma norepinephrine: isolation by boric acid gel and assay by selected ion monitoring.

An accurate and time-saving method for the determination of norepinephrine in human plasma is described. The whole device focused on an improvement in the pretreatment. One ml of human plasma was applied to a boric acid gel column without deproteinization and pH adjustment, and norepinephrine was eluted with 2 ml of a 1.3 M acetic acid in methanol solution. The pentafluoropropionic derivative of norepinephrine was analysed by gas chromatography mass spectrometry using deuterated norepinephrine as an internal standard. The level of plasma norepinephrine in healthy subjects at recumbency was 297 +/- 95 pg ml-1 (mean +/- SD). The lower limit of sensitivity was 25 pg ml-1 of norepinephrine in plasma.

Adult↗
PubMed2003

Boric acid reversibly inhibits the second step of pre-mRNA splicing.

Several approaches have been used to identify the factors involved in mRNA splicing. None of them, however, comprises a straightforward reversible method for inhibiting the second step of splicing using an external reagent other than a chelator. This investigation demonstrates that the addition of boric acid to an in vitro pre-mRNA splicing reaction causes a dose-dependent reversible inhibition effect on the second step of splicing. The mechanism of action does not involve chelation of several metal ions; hindrance of 3' splice-site; or binding to hSlu7. This study presents a novel method for specific reversible inhibition of the second step of pre-mRNA splicing.

Boric Acids↗
PubMed1999

Structural analysis of diols by electrospray mass spectrometry on boric acid complexes.

A method is presented to characterize diols using negative ion electrospray (ES) mass spectrometry in combination with collision-induced dissociation tandem mass spectrometry (MS/MS). The analyte diol is added to a solution containing an ethylene glycol/boric acid [2:1] complex and then subjected to infusion ES. The following boric acid complexes are formed: (i) a complex with two ethylene glycol molecules, (ii) a mixed ethylene glycol/analyte complex, and (iii) a complex with two analyte molecules. The first complex serves as a reference for the assessment of the extent of complex formation with the analyte. The ES mass spectra of acyclic vicinal diols all feature intense mixed complex signals, indicative of efficient complex formation. Chemical fine tuning is achieved by MS/MS experiments. Thus, although the (2R,3R)-(-)-2,3-butanediol and meso-2,3-butanediol stereo-isomers show the same complexation efficiency, MS/MS experiments reveal pronounced structure characteristic differences. By contrast, 1,3- and 1,4-diols are less prone to complex formation as they give only weak signals relative to the reference. For cyclic vicinal diols only the cis isomer produces an intense mixed complex, whose MS/MS spectrum is characteristically different from that of the trans form. The above procedure does not permit an unambiguous differentiation of acyclic polyhydroxy compounds like mannitol and sorbitol. However, structurally related methyl glycosides show characteristic MS/MS spectra. Our findings indicate that the above simple procedure may be useful to probe the presence and structure of diols and other polyols in aqueous solutions. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed1978

[Demonstration of bacteriostatic substances in boric acid preserved urine specimens].

The results of bacterilogical investigations of urine specimens which contain chemotherapeutics or other germ-inhibiting substances are to be used only with limitation. In order to avoid malinterpretations of microbiological findings by unknown natibacterial autoactivity of the investigation material the routine proof of germ-inhibiting substances in the urine by means of a simple agar diffusion test has proved. By preservation of boric acid which is to be recommended for a longer transport of urine specimens which are to be investigated bacteriologically the results of the inhibitor tests is not falsified.

Bacillus subtilis↗
PubMedDate not supplied

Assay of calcium borogluconate veterinary medicines for calcium gluconate, boric acid, phosphorus, and magnesium by using inductively coupled plasma emission spectrometry.

An inductively coupled plasma spectrometric method is described for the determination of 4 elements (Ca, B, P, and Mg) in calcium borogluconate veterinary medicines. Samples are diluted, acidified, and sprayed directly into the plasma. Reproducibility relative confidence intervals for a single sample assay are +/- 1.4% (calcium), +/- 1.8% (boron), +/- 2.6% (phosphorus), and +/- 1.4% (magnesium). The total element concentrations for each of 4 elements compared favorably with concentrations determined by alternative methods. Formulation estimates of levels of calcium gluconate, boric acid, phosphorus, and magnesium salts can be made from the analytical data.

Animals↗
PubMed1975

[Prophylaxis of influenza with a clathrate of polyvinyl alcohol with iodine and boric acid].

Taking advantage of the viricdal and antimicrobial properties of the clathrate of polyvinyl alcohol with iodine and boric acid (PVAIB) and taking into account successful results obtained during the action in 1969, it was used again as a preventive measure during the epidemy of influenza in Poznań at the turn of 1971/1972. In this period, the prophylactic action included 1477 persons who recieved the drug as nasal drops in 30 gram bottles. After the extinction of influenza we checked 459 persons who had taken the drug regularly, according to medical prescription. Out of this group, only 23 persons or 5% fell ill with influenza. If compared with general morbidity, this rate proved to be four times smaller.

Administration, Intranasal↗
PubMed1991

An outbreak of aflatoxicosis and boric acid poisoning in Malaysia: a clinicopathological study.

An outbreak of food poisoning resulting in 13 deaths in children occurred in Malaysia during the Chinese Festival of the Nine-Emperor Gods in 1988. The offending food was a Chinese noodle called 'Loh See Fun' (LSF). The source was traced to a factory where a banned food preservative was added to make the LSF. The food poisoning was attributable to aflatoxins and boric acid. The clinical features included vomiting, pyrexia, diarrhoea, abdominal pain, anorexia, giddiness, seizures, and eventual coma. Initially, many presented with a Reye-like syndrome. Eleven post-mortem examinations were performed. The pathological findings included extensive coagulative necrosis of the liver with proliferative 'ductal/ductular metaplasia of the hepatocytes'. Giant cell formation, central vein sclerosis, bile stasis, and steatosis were also noted. There was presence of acute tubular necrosis, superficial upper gastrointestinal erosions, and ensuing encephalopathy. The eventual cause of death is acute hepatic and renal failure.

Aflatoxins↗
PubMed1997

Effect of boric acid solution on cartilage metabolism.

Pelvic cartilage of chick embryo was used to demonstrate that presence of boron in culture medium decreases synthesis of proteoglycans, collagen and total proteins but on the other hand increases the release of these macromolecules. However, when glucose concentration in culture medium is brought to 22mM, the synthesis decrease is no longer observed, whereas release increase persists. Proteins released into the culture medium included heat shock proteins (70 hsp) and tumor necrosis factor alpha (TNF alpha). The amount of phosphorylated proteins was enhanced in presence of boron while endoprotease activity in cartilage and in culture medium was significantly augmented. The in vitro effects of boric acid may explain its in vivo effect on wound healing.

Animals↗
PubMed1991

[Contribution of a 3% solution of boric acid in the treatment of deep wounds with loss of substance].

The correct application of antiseptics to major surgical wounds must comply with appropriate protocols. Compliance with the protocol established by the CHRU of Nancy was evaluated by means of a questionnaire assessing the understanding of the protocol by the nursing staff and by a survey in the wards in which it was applied. The defects observed cannot be explained by a lack of efficacy for superficial wounds and deep wounds, as a randomised study of 42 wounds demonstrated the superiority of the protocol in relation to the use of another product which is widely used in the wards. In contrast, for deep wounds with loss of substance, the proposed protocol does not always achieve therapeutic success. This finding has led the authors to propose the use of a 3% boric acid solution based on a case-control study which demonstrated a significantly superior efficacy. All of the epidemiological and clinical elements are summarised in order to demonstrate the solid basis for compliance with antiseptic protocols of surgical wounds which can only be beneficial in terms of therapeutic success, length of hospital stay and cost savings.

Anti-Infective Agents, Local↗
PubMed2005

Determination of isotopic ratio of boron in boric acid using laser mass spectrometry.

A reflectron time-of-flight mass spectrometer (RTOFMS) with a laser ablation ion source was used to determine the isotopic ratio of 10B/11B present in boric acid solutions, using graphite as the matrix. The atom % 10B values obtained were within +/-1% of the actual ones. The determination of the boron isotopic ratio using this method is, in comparison to other methods, faster, less expensive and easier to perform. The results are compared with the values determined using thermal ionization mass spectrometry.

Journal Article↗
PubMed2001

New methods of resolution and purification of racemic and diastereomeric amino alcohol derivatives using boric acid and chiral 1,1'-bi-2-naphthol.

Resolution of the racemic amino alcohol derivatives 1-6 is readily achieved to obtain enantiomerically enriched compounds using chiral 1,1'-bi-2-naphthol and boric acid in solvents such as CH(3)CN, THF, and MeOH. Purification of the diastereomeric mixture 7 has also been carried out following this method. The corresponding intermediate ammonium borate complexes were also characterized by X-ray diffraction methods.

Journal Article↗