Development of a universal diluting fluid for membrane filtration sterility testing.
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A universal diluting fluid (UDF) was developed for use in membrane filtration sterility testing. Diuting fluid is used to free the filter membrane of preservative residues which could inhibit microbial recovery. Current procedures employ one of several fluids described by the United States Pharmacopeia. UF was designed to utilize the neutralizing capabilities of a combination of inactivating agents while minimizing any inherent microbial toxicity. This formulation eliminates the need for multiple types of preservative-specific diluting fluids. Its neutralizing effectiveness was examined against several common preservative agents used in health care products. UDF provides significantly better microorganism recovery than dilution alone among a wide range of preservative classes. (+info)
Tissue-mimicking liquid for use in exposimetry.
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OBJECTIVE: Current determinations of diagnostic ultrasound exposure parameters (eg, peak rarefactional pressure and pulse intensity integral) are intended to correspond to propagation through soft tissue with a propagation speed of 1540 m/s and attenuation of 0.3 dB x cm(-1) x MHz(-1). These current measurements are made in water, which has very little attenuation, and a linear derating factor is applied to approximate 0.3 dB x cm(-1) x MHz(-1) attenuation. The fact that propagation through water as well as through soft tissue involves nonlinear propagation is not directly addressed. A better way to determine exposure parameters would be to use a liquid that has the desired tissue-mimicking properties, including a value of the nonlinearity parameter B/A representative of soft tissue. To be of practical use in the laboratory, the ultrasonic properties of this liquid must remain stable and spatially uniform for many months or years without need for periodic mixing by the user. METHODS: Fifty-two samples of fat-free milk that was concentrated to one third of its original volume by ultrafiltration were created. Each sample was preserved by a different method. The speed of sound, attenuation, and nonlinearity parameter B/A of each sample were periodically monitored by narrowband through-transmission techniques. RESULTS: Six of the 52 samples remained liquid and retained acceptably stable acoustic properties over 22 months of storage at room temperature. CONCLUSIONS: Fat-free milk, concentrated via ultrafiltration and preserved in 1 of 6 different methods, has been found to be a stable tissue-mimicking liquid with acoustic properties appropriate for use in exposimetry. (+info)
Evaluation of phototoxic properties of antimicrobials used in topical preparations by a photohaemolysis test.
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Antimicrobials are widely used in topical formulations as preservatives or as therapeutically active agents. Photosensitization by such compounds has not yet been studied systematically. To identify possible phototoxic properties, antimicrobials (benzyl alcohol, bronopol, chloracetamide, clioquinol, diazolidinyl urea, ethylenediamine dihydrochloride, formaldehyde, glutaraldehyde, imidazolidinyl urea, sodium benzoate, propylene glycol) were evaluated in vitro by means of a photohaemolysis test using suspensions of human erythrocytes. Irradiations were performed with UVA- and UVB-rich light sources. In the presence of bronopol or clioquinol, there was photohaemolysis up to 78.1% or 48.5% with UVA and up to 100% or 34.3% with UVB, respectively. The phototoxic effect depended on the concentration of the compounds and the UV doses administered. None of the other substances tested caused significant photohaemolysis. It is concluded that bronopol and clioquinol exert phototoxic effects in vitro and thus might also cause photosensitization when used on the skin. The clinical significance of this has to be established by further work. (+info)
Dextrose in the banked blood products does not seem to affect the blood glucose levels in patients undergoing liver transplantation.
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AIM: Hyperglycemia commonly seen in liver transplantation (LT) has often been attributed to the dextrose in the storage solution of blood transfusion products. The purpose of the study is to compare the changes of the blood glucose levels in transfused and non-transfused patients during LT. METHODS: A retrospective study on 60 biliary pediatric patients and 16 adult patients undergoing LT was carried out. Transfused pediatric patients were included in Group I (GI), those not transfused in Group II (GII). Twelve adult patients were not given transfusion and assigned to Group III (GIII); whereas, four adult patients who received massive transfusion were assigned to Group IV (GIV). The blood glucose levels, volume of blood transfused, and the volume of crystalloid infused were recorded, compared and analyzed. RESULTS: Results showed that the changes in blood glucose levels during LT for both non-transfused and minimally transfused pediatric groups and non-transfused and massively-transfused adult groups were almost the same. CONCLUSION: We conclude that blood transfusion does not cause significant changes in the blood glucose levels in this study. (+info)
Low incidence of paradoxical bronchoconstriction in asthma and COPD patients during chronic use of Respimat soft mist inhaler.
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Respimat Soft Mist Inhaler (SMI) is a new-generation inhaler that offers improved lung deposition compared with chlorofluorocarbon metered dose inhalers (CFC-MDIs). Bronchodilators administered via Respimat SMI are preserved and stabilised with low concentrations of benzalkonium chloride and ethylene diamine tetra-acetic acid, both of which have been reported to cause dose-related paradoxical bronchoconstriction. The aim of this analysis was to compare the incidence of paradoxical bronchoconstriction after chronic use of bronchodilators via Respimat SMI and CFC-MDI. Data from three clinical trials, in which patients with asthma or chronic obstructive pulmonary disease (COPD) received ipratropium bromide alone or in combination with fenoterol hydrobromide, or placebo via Respimat SMI or CFC-MDI for 12 weeks, were included in the analysis. In order to evaluate the risk of paradoxical bronchoconstriction, we identified four respiratory events that might have occurred within 30 min of inhalation on four test days; these were: 'bronchospasm', 'other respiratory adverse events', 'rescue medication use' and 'asymptomatic drop in FEV(1) 15% from baseline'. In total, 631 asthma and 1538 COPD patients participated in the three studies. No occurrences of bronchospasm were reported with Respimat SMI on any test day. Overall, the incidence of respiratory events possibly indicative of paradoxical bronchoconstriction was low and similar for both devices. There was no increase in the incidence of events during 12 weeks' treatment. Delivery of bronchodilators by Respimat SMI is safe with regard to paradoxical bronchoconstriction during chronic use in patients with asthma or COPD. (+info)
In vitro study of inflammatory potential and toxicity profile of latanoprost, travoprost, and bimatoprost in conjunctiva-derived epithelial cells.
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PURPOSE: Conjunctiva-derived epithelial cells were used to investigate, in vitro, the expression of various inflammation-associated markers known to be overexpressed in patients with glaucoma after contact with the three major commercially available eye drops containing prostaglandin analogues. The impact on cellular viability and apoptosis in the same cell line was evaluated, to address the possible proinflammatory and/or toxic origin of the most frequent clinical impairments induced by prostanoids (i.e., conjunctival hyperemia). METHODS: Conjunctiva-derived cells were treated in vitro with the commercial solutions of latanoprost, travoprost, bimatoprost, prostaglandin (PG)F2alpha, tumor necrosis factor (TNF)-alpha, and different concentrations of benzalkonium chloride (BAC). Expressions of three inflammation- and immune-related markers, intercellular adhesion molecule (ICAM)-1, platelet-endothelial cell adhesion molecule (PECAM)-1 and HLA DR, were evaluated with flow cytometry after 24 to 72 hours of contact at low, subtoxic concentrations. Toxicological tests were also performed with cold-light cytofluorometry, in which cellular viability and apoptosis were evaluated with the neutral red and Hoechst/propidium iodide tests, respectively. RESULTS: TNFalpha induced or stimulated expression of the three inflammatory markers, whereas the PGF2alpha, latanoprost, travoprost, and bimatoprost solutions did not induce an increase in these markers and even produced a marked reduction of ICAM-1 and PECAM-1 expression in those solutions most concentrated in BAC, thus suggesting a toxic phenomenon in cellular membranes induced by the preservative rather than the medication itself. Cytotoxic assays confirmed this hypothesis and showed significant toxicity with prostaglandin analogues after prolonged contact, proportional to the concentration of BAC in the solution and similar to that of the corresponding concentration of BAC alone, bimatoprost having both the least concentration of BAC and the least cytotoxic in these experimental conditions. CONCLUSIONS: The comparison of latanoprost, travoprost, and bimatoprost, in their commercial formulations, showed that none of them appeared to induce direct stimulation of the inflammatory pathways involving adhesion molecules or class II antigens, although these markers have been found ex vivo in conjunctival specimens from patients treated with prostaglandins. In fact, their toxicity was mild and seemed to be primarily related to the concentration of BAC, their common preservative, which may be the major factor responsible for long-term ocular surface reactions in patients receiving topical prostaglandins, but most likely is not a factor in early and transient conjunctival hyperemia. (+info)
A method for the obtaining of increased viscosity eye drops containing amikacin.
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A method for the obtaining of increased viscosity (3.6-52.5 cP) eye drops, containing amikacin-aminoglycoside antibiotic and as increasing viscosity agents: polivinyl alkohol, hydroxyethylcellulose or sodium hyaluronate was elaborated. Physicochemical and biological properties of these eye drops were determined. (+info)
Comparison of blood and brain mercury levels in infant monkeys exposed to methylmercury or vaccines containing thimerosal.
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Thimerosal is a preservative that has been used in manufacturing vaccines since the 1930s. Reports have indicated that infants can receive ethylmercury (in the form of thimerosal) at or above the U.S. Environmental Protection Agency guidelines for methylmercury exposure, depending on the exact vaccinations, schedule, and size of the infant. In this study we compared the systemic disposition and brain distribution of total and inorganic mercury in infant monkeys after thimerosal exposure with those exposed to MeHg. Monkeys were exposed to MeHg (via oral gavage) or vaccines containing thimerosal (via intramuscular injection) at birth and 1, 2, and 3 weeks of age. Total blood Hg levels were determined 2, 4, and 7 days after each exposure. Total and inorganic brain Hg levels were assessed 2, 4, 7, or 28 days after the last exposure. The initial and terminal half-life of Hg in blood after thimerosal exposure was 2.1 and 8.6 days, respectively, which are significantly shorter than the elimination half-life of Hg after MeHg exposure at 21.5 days. Brain concentrations of total Hg were significantly lower by approximately 3-fold for the thimerosal-exposed monkeys when compared with the MeHg infants, whereas the average brain-to-blood concentration ratio was slightly higher for the thimerosal-exposed monkeys (3.5 +/- 0.5 vs. 2.5 +/- 0.3). A higher percentage of the total Hg in the brain was in the form of inorganic Hg for the thimerosal-exposed monkeys (34% vs. 7%). The results indicate that MeHg is not a suitable reference for risk assessment from exposure to thimerosal-derived Hg. Knowledge of the toxicokinetics and developmental toxicity of thimerosal is needed to afford a meaningful assessment of the developmental effects of thimerosal-containing vaccines. (+info)