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PubMedDate not supplied

Use of sodium hydroxide solution to clear partially occluded vascular access ports.

Gradual vascular access port or tunneled central venous catheter occlusion during total parenteral nutrition is a common complication of unknown etiology, usually unresponsive to treatment with urokinase, ethanol, or hydrochloric acid. After establishing safety with regard to catheter materials and efficacy in dissolving the occluding substance in vitro, we treated a total of 13 vascular access ports (10 patients) that had occluded gradually during "three-in-one" total parental nutrition by slow perfusion with 10 to 20 mL of 0.1 mmol/mL sodium hydroxide solution. We found a mean increase in flow (results are flow rates under gravity-dependent vascular access port inlet pressure of 1.5 kPa) from 37 microL/s (95% upper confidence limit, 45 microL/s) to 75 microL/s (95% lower confidence limit, 64 microL/s; p < .001). For normal use, a flow of 50 microL/s is sufficient. There were no side effects. Five vascular access ports remained in excellent function during a follow-up period of 9 months. The others had reocclusions, but the partial reocclusions could be treated successfully.

Catheters, Indwelling↗

PubMedDate not supplied

Microscopic changes with acetic acid and sodium hydroxide in the rabbit low-volume eye test.

Differences in ocular irritancy have been hypothesized to reflect differences in the extent of initial injury. Although differences in the processes leading to tissue damage may exist, extent of injury is believed to be the principal factor determining final outcome of ocular irritation. Previous studies characterizing the pathology of surfactant-induced ocular irritation support this premise. The purpose of this study was to begin to determine the applicability of this premise in terms of nonsurfactants; we planned to accomplish this by assessing the ocular irritancy of different concentrations of an acid and an alkali. Ten microliters of 3 or 10% acetic acid (C2H4O2) or 2 or 8% sodium hydroxide (NaOH) were directly applied to the cornea of the right eye of each test rabbit. Untreated left eyes served as the controls. Eyes and eyelids were macroscopically examined for signs of irritation beginning 3 hours after dosing and periodically until recovery or day 35. Eyes and eyelids from animals in each group were collected for microscopic examination after 3 hours and on days 1, 3, and 35. The macroscopic and microscopic changes were consistent with slight (3% C2H4O2), mild (2% NaOH, 10% C2H4O2), and severe (8% NaOH) irritancy. The spectra of changes were similar to those previously reported for surfactants of differing types and irritancies. As with surfactants, as the extent of initial injury increased, the intensity and duration of the subsequent responses increased. These results indicate that our hypothesis also applies to nonsurfactants. The results also support our belief that the initial extent of injury associated with ocular irritation may be used to predict the subsequent responses and final outcome. Finally, our results further indicate that such an approach may be applicable to the development of alternative assays that are based on either injury to ex vivo eyes or injury to an in vitro corneal equivalent system.

Acetic Acid↗

PubMed1989

Hyperaluminaemia associated with oral citrate and aluminium hydroxide.

1. A hospitalized patient with renal failure receiving oral aluminium hydroxide was found to have a blood aluminium level of 3124 micrograms/l (116 mumol/l). 2. The extremely high aluminium concentration was attributed to the concurrent use of an oral citrate solution which converted the aluminium to a more soluble and absorbable form. 3. The combination of oral aluminium and citrate should be avoided in patients with poor renal function.

Administration, Oral↗

PubMed2005

Barium hydroxide lime turns yellow after desiccation.

Ethyl violet is added to carbon dioxide absorbents and normally serves as an indicator of absorbent exhaustion. During the course of several prior studies of anesthetic breakdown, we noted (but did not publish) that barium hydroxide lime (BL), but not soda lime, turns yellow upon desiccation. We hypothesize that ethyl violet undergoes chemical reaction to produce a yellow colorant in desiccated BL. We qualitatively studied the time course of yellow color development during desiccation of these absorbents with dry oxygen. The yellow colorant was extracted from desiccated absorbent with diethyl ether, separated with chromatography, and analyzed with proton nuclear magnetic resonance and combined gas chromatography and mass spectrometry. The yellow color develops after BL has reached nearly complete desiccation. We successfully identified that ethyl violet decomposes into the yellow colorant 4,4'-bis(diethylamino)benzophenone upon desiccation of BL. The color is not intense, is not useful for identifying low levels of absorbent desiccation, and may be difficult to see through tinted canisters. It may be possible for BL to be sufficiently desiccated to allow chemical breakdown of anesthetics, but not yet show yellow coloration. However, if yellow coloration exists, one should assume that it has become desiccated.

Anesthesiology↗

PubMed1981

The bioavailabilities of aspirin from an aspirin aluminum and an aspirin tablet and the effects of food and aluminum hydroxide gel.

The bioavailability of aspirin from an aspirin aluminum tablet was compared with that from an aspirin tablet in humans by determining total salicylate excreted in the urine. The effects of concomitant intakes of antacid or food on the bioavailability of aspirin were also investigated. The bioavailability of aspirin from an aspirin aluminum tablet was nearly 60% of that from an aspirin tablet. The low bioavailability of aspirin from an aspirin aluminum tablet was caused by slow release of aspirin from the aluminum complex, and not increased by concomitant intake of food. Intake of food, however, reduced both rate and extent of bioavailability of aspirin from an aspirin tablet, but dried aluminum hydroxide gel granules had no effect on the bioavailability of it.

Adult↗

PubMed1982

The bioavailability of flufenamic acid from aluminum flufenamate tablet and flufenamic acid capsule, and the influence of food and aluminum hydroxide gel.

The bioavailabilities of flufenamic acid (I) from a commercial aluminum flufenamate (II) tablet and I capsule were estimated by measuring urinary excretion of I and its metabolites fluorometrically. The dissolution rates of I from both dosage forms were also determined. The effects of concomitant intake of food or antacid on the bioavailabilities from the II tablet and the I capsule were investigated. The extent on I bioavailability from the II tablet was less than 30% of that from the I capsule. Dissolution tests suggested that the low bioavailability of I from II tablet resulted from the extremely slow release of I from the II complex. Intake of a standard meal retarded I absorption from I capsule, but did not affect that from the II tablet. Ingestion of dried aluminum hydroxide gel granules had little effect on I bioavailability from the I capsule.

Adult↗

PubMed1997

Effects of quaternary ammonium compounds with 0.1% sodium hydroxide on swine vesicular disease virus.

The effects of quaternary ammonium compounds (QACs) with sodium hydroxide on swine vesicular disease virus (SVDV), an enterovirus were studied. Didecyldimethylammonium chloride (DDAC) with 0.1% NaOH showed a stronger effect against SVDV than other QACs with 0.1% NaOH. The effect of DDAC with 0.1% NaOH was strong at 40 degrees C. DDAC was effective against SVDV at pH values around 11.0, but not in the distilled water control. The effect of DDAC with 0.1% NaOH was already observed at 1 min after mixing of the DDAC with SVDV. Observation under an electron microscopy revealed that the probable mechanism of inactivation of DDAC with 0.1% NaOH is as follows: The virus particles were partially destroyed by 0.1% NaOH. DDAC gathered these affected particles and formed a micelle, then SVDV lost its infectivity. From these results, QACs with 0.1% NaOH are considered to be very effective against SVDV representing enteroviruses.

Animals↗

PubMedDate not supplied

Immobilization of lipase from Candida rugosa on layered double hydroxides for esterification reaction.

Synthesis of layered double hydroxides (LDHs) of Zn/Al-NO3- hydrotalcite (HIZAN) and Zn/Al-diocytyl sodium sulfosuccinate (DSS) nanocomposite (NAZAD) with a molar ratio of Zn/Al of 4:1 were carried out by coprecipitation through continuous agitation. Their structures were determined using X-ray diffractometer spectra, which showed that basal spacing for LDH synthesized by both methods was about 8.89 A. An expansion of layered structure of about 27.9 A was observed to accommodate the surfactant anion between the interlayer. This phenomenon showed that the intercalation process took place between the LDH interlayer. Lipase from Candida rugosa was immobilized onto these materials by physical adsorption method. It was found that the protein loading onto NAZAD is higher than HIZAN. The activity of immobilized lipase was investigated through esterification of oleic acid and 1-butanol in hexane. The effects of pore size, surface area, reaction temperature, thermostability of the immobilized lipases, storage stability in organic solvent, and leaching studies were investigated. Stability was found to be the highest in the nanocomposite NAZAD.

Candida↗

PubMed1984

Acid and water solubility and strength of calcium hydroxide bases.

The solubility in water and 37% phosphoric acid, and compressive strength of four brands of hard-setting calcium hydroxide base materials were studied. Results were highly variable among brands and no correlations appeared to exist between properties studied. One product was significantly different from the others with regard to acid solubility and compressive strength.

Calcium Hydroxide↗

PubMed1989

Calcium hydroxide in the treatment of external root resorption.

A case is presented in which calcium hydroxide was used in endodontic treatment of external root resorption in a tooth with a necrotic pulp, during active orthodontic movement. A calcified deposit formed, filling a defect, and the tooth was subsequently obturated with gutta-percha. Thus, both types of therapy--endodontic and orthodontic--were performed simultaneously.

Adolescent↗

PubMed2005

Remineralization of carious dentin. II: In vivo microradiographic and chemical studies in human permanent teeth capped with calcium hydroxide.

The main aim of this in vivo study was to evaluate a possible remineralization of human carious dentin by means of chemical and microradiographic studies. Eighty-six samples of carious dentin were removed from 36 permanent teeth of 24 patients. These were divided into untreated (control) and chemically pure calcium hydroxide-capped (experimental) samples and analyzed at intervals varying from 10 to 120 days. They were classified according to depth of caries and degree of dentin softening and evaluated in relation to weight, phosphorus concentration, qualitative and quantitative microradiography and absolute values of total mineral content. One of two halves of each sample was selected for chemical studies and the other for total content of mineral salts. Experimental samples were examined with a light microscope and the results obtained showed a qualitative increase in radiopacity. Quantitatively, it was observed that, in the case of samples analyzed for phosphorus concentration, the average mean of differences in percentage increase after treatment was 9.6%, while for the samples evaluated microradiographically for total mineral content, it was 22.29%. In both cases, the differences were statistically significant.

Adolescent↗

PubMed2005

Electron paramagnetic resonance analysis of the distribution of a hydrophobic spin probe in suspensions of humic acids, hectorite, and aluminum hydroxide-humate-hectorite complexes.

Until recently, there were no techniques capable of direct observation of the microscale locations where nonpolar organic compounds accumulate when associated with natural geosorbents. The ability of electron paramagnetic resonance (EPR) spectroscopy to monitor and elucidate directly the different molecular-scale environments of paramagnetic spin probes has been demonstrated lately in model soils, yet it remains untested in complex systems. In this general context, the present investigation was aimed at assessing the extent to which EPR could be used to monitor the sorption of 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy benzoate (TEMPO benzoate), a hydrophobic spin probe, on a smectite (hectorite), two humic acids, and their complexes in the presence or absence of aluminum hydroxide. Results demonstrate that EPR is able to monitor easily adsorption on these sorbents in batch-style experiments. Distribution coefficient (Kd) values of 455.4 and 483.1 ml/g were found for the adsorption of TEMPO benzoate on hectorite-humic acids complexes, compared to respective Kd values of 46 and 147 ml/g predicted solely on the basis of the mass of humic acids present in the complexes. These observations confirm the significant role of hectorite for the sorption of hydrophobic compounds, together with humic acids, contrary to common belief that emphasizes the almost exclusive sorptive role of organic matter. In addition, for the first time, EPR is able to provide evidence that hydrophobic molecules in the presence of geosorbents can segregate in multimolecular clusters that are in equilibrium with aqueous probe concentrations below the probe's solubility threshold. Possible consequences of this clustering process in terms of the fate and transport of hydrophobic compounds in subsurface environments are discussed.

Adsorption↗

PubMed2001

Clinical comparison of microporous biocompatible composite of PMMA, PHEMA and calcium hydroxide grafts and expanded polytetrafluoroethylene barrier membranes in human mandibular molar Class II furcations. A case series.

BACKGROUND: Class II furcations present difficult treatment problems. Several treatment approaches to obtain furcation fill have been used with varying success. METHODS: The response of mandibular Class II furcations to treatment with either a microporous biocompatible composite of PMMA (poly-methyl-methacrylate), PHEMA (poly-hydroxyl-ethyl methacrylate) and calcium hydroxide graft synthetic bone (HTR) replacement graft material; ePTFE barrier membrane; or a combination of the two was evaluated in trios of mandibular molars with Class II furcations in 8 patients with moderate to advanced periodontitis. Following initial preparation, full-thickness flaps were raised in the areas being treated, the bone and furcation defects debrided of granulomatous tissue, and the involved root surfaces mechanically prepared and chemically conditioned. By random allocation, HTR, ePTFE, or a combination of both was placed into and/or fitted over the furcations, packed and/or secured in place, and the host flap replaced or coronally positioned with sutures. Postsurgical deplaquing was performed every 10 days leading up to ePTFE removal at approximately 6 weeks. Continuing periodontal maintenance therapy was provided until surgical reentry at 6 months for documentation and any further necessary treatment. RESULTS: Direct clinical measurements demonstrated essentially similar clinical results with all 3 treatments for bone and soft tissue changes. There were no statistically or clinically significant differences except for better horizontal amount and percent defect fill with HTR alone. Four of 8 furcations became Class I clinically with HTR alone, 5 of 8 became Class I with ePTFE alone, and 5 of 8 with combination treatment. The only complete furcation closure occurred with HTR. CONCLUSION: The findings of this study suggest essentially equal clinical results with HTR bone replacement graft material alone, ePTFE barrier alone, and a combination of the two in mandibular molar Class II furcations. However, a real difference may not have been detected based on the small number of subjects in the study.

Biocompatible Materials↗

PubMed2006

Comparison of plain potassium hydroxide mounts, fungal cultures and nail plate biopsies in the diagnosis of onychomycosis.

OBJECTIVE: To compare the relative sensitivity of direct microscopy, fungal culture and nail plate biopsy in the diagnosis of onychomycosis. DESIGN: Cross-sectional study. PLACE AND DURATION OF STUDY: The Skin Department, Military Hospital, Rawalpindi from February 1998 to February 1999. PATIENTS AND METHODS: A total of 50 patients who were suffering from different clinical variants of onychomycosis, irrespective of their age, gender, with or without simultaneous presence of systemic diseases, were subjected to laboratory investigations including direct microscopy with 20% potassium hydroxide (KOH) for fungal hyphae, fungal cultures and nail plate biopsies. These patients were later categorized into two groups based upon the results of nail plate biopsies. RESULTS: Of 50 patients, 15 (30%) were positive for fungal elements in direct microscopy, 8 (16%) were positive for fungal culture and 16 (32%) revealed positive results in nail plate biopsies. Amongst nail plate biopsy positive cases, 10 (63%) were positive for direct microscopy and 6 (37.5%) were positive for fungal cultures. In biopsy negative cases, positive results for direct microscopy were seen in 5 (14.7%) patients and positive fungal culture was found in 2 (5.88%) patients. CONCLUSION: The clinical impression of onychomycosis is not true in all the cases. Nail scraping for direct microscopy with 20% KOH should be the first line screening test for all patients which should then be supplemented with fungal culture and/ or nail plate biopsy.

Biopsy↗

PubMed2003

Determination of cobalt and nickel by graphite-furnace atomic absorption spectrometry after coprecipitation with scandium hydroxide.

Trace amounts of cobalt and nickel in a water sample were quantitatively coprecipitated with scandium hydroxide at pH 8.0-10.5. Because the coprecipitant could be easily dissolved with 1 mol dm(-3) nitric acid, and the presence of up to 10 mg cm(-1) of scandium did not interfere with the graphite-furnace atomic absorption spectrometric determination of cobalt and nickel, the volume of the final solution prepared for the determination could be minimized down to 0.5 cm3. The concentration factor was 400-fold and the detection limits (signal to noise = 2) were 5.0 pg cm(-3) of cobalt and 10.0 pg cm(-3) of nickel in 200 cm3 of the initial sample solution. The 27 diverse ions investigated did not interfere with the determination in at least a 500-fold mass ratio to cobalt or nickel. The proposed method was successfully applied to the determination of trace amounts of cobalt and nickel in river-water samples.

Calibration↗

PubMedDate not supplied

Sorption of MS2 bacteriophage to layered double hydroxides: effects of reaction time, pH, and competing anions.

Batch sorption and column breakthrough studies were conducted to investigate the potential of layered double hydroxides (LDHs) to remove bacteriophage MS2 from contaminated waters. All four of the LDHs evaluated in this study had very high retention capacities for MS2. Sorption results showed that MS2 could be completely removed from 5.2 x 10(2) plaque-forming units (pfu)/mL solution by Mg-Al LDH 2 (i.e., 2:1 Mg to Al ratio LDH), with the highest sorption capacity observed in this study of 1.51 x 10(10) pfu/g. Attachment of MS2 to LDHs was a rapid process and reached quasi-equilibrium after a 1-h reaction time. Within the pH range studied (pH 4-9), Mg-Al LDH 2 showed high sorption potential for MS2 at all pH values but sorption decreased slightly with increasing solution pH. Background solution anions influenced virus sorption, with SO4(2-) and HPO4(2-) decreasing sorption significantly whereas the presence of NO3- had little effect on the attachment of MS2 to Mg-Al LDH 2. The addition of another virus (phiX174) only caused a slight decrease in the retention of MS2 by Mg-Al LDH 2, suggesting that there was insignificant competitive sorption between MS2 and phiX174 on LDH surfaces. Results from column experiments indicate that there was no MS2 breakthrough from columns packed with Mg-Al LDH 2-coated sand, suggesting complete MS2 retention at the virus concentration tested. The high mass recovery by beef extract solution revealed that the removal of viruses by the LDH was due to sorption of MS2 to LDH surfaces, rather than inactivation.

Adsorption↗

PubMedDate not supplied

Equilibrium and kinetics of color removal from dye solutions with bentonite and polyaluminum hydroxide.

Wastewater from the textile industry contains soluble dyes that are toxic and particularly difficult to remove. A promising low-cost treatment, however, is use of polyaluminum hydroxide associated with bentonite. At suitable conditions, this process is able to efficiently remove color from solutions containing mixtures of soluble acid azo dyes and produce easily settleable sludge. The removal mechanism, which is believed to involve adsorption or precipitation and weak pH variations, is not well understood. With the overall reaction being second order, two elementary first-order reactions could be assumed. The equilibrium removal is a decreasing function of the temperature. However, this effect is weak and decreases when the dye concentration increases. At usual values of concentration in textile wastewater, this effect can be neglected. The resulting solid compound is particularly resistant to mechanical stress. Moreover, color was significantly released at pH greater than 8. Sodium ions have no influence on the compound stability, which reinforces the assumption of the involvement of an adsorption process.

Aluminum Hydroxide↗

PubMed1995

Sodium hydroxide-induced irritant dermatitis as assessed by computerized elaboration of 20 MHz B-scan images and by TEWL measurement: a method for investigating skin barrier function.

Sodium hydroxide-induced irritation was studied in 34 volunteers, by means of 24-h patch testing at different concentrations, and by a 10-min testing procedure employing 0.1 mol/l NaOH. As a supplement to subjective evaluation of skin changes, assessments of test areas by TEWL measurement and sonography were performed at 24, 48 and 72 h. After 24-h patch testing, instrumental evaluations showed an increase in the extension of the hypo-echogenic dermal area and in TEWL, whereas a 10-min NaOH application induced a decrease of the dermal and epidermal reflectivity and an increase in TEWL. Twenty-four hour patch testing with 4% NaOH allowed a classification of subjects into two categories: subjects who reacted normally and hyper-reactors. Hyper-reactors showed an enhanced inflammatory response and a more pronounced barrier function damage, as assessed clinically and instrumentally by decreased dermal reflectivity, and by higher postexposure TEWL. Subjects with a more marked inflammatory response to 4% NaOH also showed greater TEWL increases during the short-term testing procedure employing 0.1 mol/l NaOH. Moreover, these subjects were characterized by higher baseline TEWL values, indicating that cutaneous reactivity to NaOH is at least partly correlated to impaired stratum corneum function, which is inadequate to effectively prevent compounds from penetrating the skin.

Adolescent↗