Evaluation of ultrasonic scaling unit waterline contamination after use of chlorine dioxide mouthrinse lavage

BACKGROUND: An infection control problem in dental operatories which is not fully controlled is waterline contamination by heterotrophic mesophilic bacteria. These bacteria are present in water supplies as a planktonic phase and adhere to the lumen of tubings as a biofilm comprised of their external cell surface glycocalyx and by production of extracellular carbohydrate polymers. The adherent film is most difficult to remove. The accumulated planktonic phase can be reduced significantly by flushing water from the lines before use in patient treatment, but will return when the equipment is idle through the accumulation of more planktonic phase and by slough of the biofilm surface-adsorbed phase not yet enmeshed in the carbohydrate matrix. Chlorine dioxide has antimicrobial activity against many bacteria, spores, and viruses. It is used in water supply treatment as a disinfectant and slime preventive and has an advantage over chlorine in that carcinogenic trihalomethanes are not generated. METHODS: This study compared use of phosphate buffer-stabilized chlorine dioxide (0.1%) mouthrinse as a lavage in ultrasonic dental scaler units with the use of tap water as a control. Sterile water flushed through the units onto heterotrophic plate count (HPC) sampler plates was cultured 7 days at room temperature and colonies were counted at 12x. One test and one control unit were used for biopsy of internal tubing and scanning electron microscopy imaging. RESULTS: The HPC counts, in colony forming units (CFU)/ml, were reduced 3- to 5-fold by flushing tap water through the units, but they returned after units were idle overnight. When phosphate-buffered chlorine dioxide mouthrinse was used as a lavage, CFU/ml were reduced 12- to 20-fold. Holding chlorine dioxide in waterlines overnight reduced recurrent buildup compared to water (P <0.05). Scanning electron microscopy images indicated a significant reduction of biofilm coverage by chlorine dioxide as compared to water (P<0.001). CONCLUSIONS: Phosphate-buffered chlorine dioxide mouthrinse was effective in these short-term trials for control of waterline contamination in ultrasonic dental scaling units. It should prove as useful in dental professional waterline applications as it has in industrial uses for biofilm control.     

Absolute oral bioavailability of rosuvastatin in healthy white adult male volunteers

BACKGROUND: Rosuvastatin is a 3-hydroxy-3-methylglutaryl coenzyme A-reductase inhibitor developed for the treatment of dyslipidemia. The results of clinical trials suggest that it is effective and well tolerated. OBJECTIVES: The goals of this study were to determine the absolute bioavailability of an oral dose of rosuvastatin and to describe the intravenous pharmacokinetics of rosuvastatin in healthy volunteers. METHODS: This was a randomized, open-label, 2-way crossover study consisting of 2 trial days separated by a > or =7-day washout period. Healthy male adult volunteers were given a single oral dose of rosuvastatin 40 mg on one trial day and an intravenous infusion of rosuvastatin 8 mg over 4 hours on the other. Pharmacokinetic and tolerability assessments were conducted up to 96 hours after dosing. A 3-compartment pharmacokinetic model was fitted to the plasma concentration-time profiles obtained for each volunteer after intravenous dosing. RESULTS: Ten white male volunteers entered and completed the trial. Their mean age was 35.7 years (range, 21-51 years), their mean height was 177 cm (range, 169-182 cm), and their mean body weight was 77.6 kg (range, 68-85 kg). The absolute oral bioavailability of rosuvastatin was estimated to be 20.1%,and the hepatic extraction ratio was estimated to be 0.63. The mean volume of distribution at steady state was 134 L. Renal clearance accounted for approximately 28% of total plasma clearance (48.9 L/h). Single oral and intravenous doses of rosuvastatin were well tolerated in this small number of healthy male volunteers. CONCLUSIONS: The absolute oral bioavailability of rosuvastatin in these 10 healthy volunteers was approximately 20%, and absorption was estimated to be 50%. The volume of distribution at steady state was consistent with extensive distribution of rosuvastatin to the tissues. The modest absolute oral bioavailability and high hepatic extraction of rosuvastatin are consistent with first-pass uptake into the liver after oral dosing. Rosuvastatin was cleared by both renal and nonrenal routes; tubular secretion was the predominant renal process.     

Excretory urography with iohexol: evaluation in children

A multicenter clinical study was conducted using iohexol, a second-generation nonionic contrast medium, for excretory urography performed in 130 children. Doses of iohexol (300 mg iodine/ml) ranged between 150 and 660 mgI/kg (0.5 and 2.2 ml/kg). Iohexol was tolerated well, and no significant adverse reactions occurred. Sixty-five iohexol urograms were evaluated to determine the minimum dose for adequate visualization of the kidneys and collecting systems. A dose greater than 300 mgI/kg (1.0 ml/kg) always resulted in a urogram of diagnostic quality, while visualization was insufficient for diagnosis in 10% of studies done with doses of 150-300 mgI/kg (0.5-1.0 ml/kg). Another 65 iohexol urograms were compared in a blinded manner with a similar number of studies performed using iothalamate meglumine at comparable iodine concentration and dose. Visualization of calyces and pelvoinfundibular structures achieved with iohexol was rated better with statistical significance, but there was no difference in visualization of the renal parenchyma or ureters. Use of iohexol in excretory urography may be advantageous in children who are at greatest risk for an adverse reaction to contrast media or in those most likely to benefit from use of a low osmolality contrast agent.     

Interobserver variation in the interpretation of abdominal radiographs

A total of 140 sets of abdominal radiographs were reviewed independently by four qualified diagnostic radiologists. The degree of interobserver agreement was determined by calculating kappa values for 19 commonly used radiographic signs and diagnoses. There was fair to excellent interobserver agreement for 11 signs and diagnoses and poor agreement for the remaining eight. The signs and diagnoses for which agreement is poor cannot be considered reliable and include particularly large bowel obstruction and nonspecific gas pattern.     

Pharmacokinetics of acitretin and its 13-cis metabolite in patients on haemodialysis.

1. Plasma concentrations of acitretin and its metabolite (13-cis acitretin) were measured in six patients on haemodialysis and six subjects without renal failure following a single oral dose of 50 mg of acitretin. 2. The mean areas under the plasma concentration vs time curves of acitretin and its metabolite were about 50% lower in patients on haemodialysis. 3. No retinoids were detectable in the dialysate.     

Inhibition of autotaxin production or activity blocks lysophosphatidylcholine‐induced migration of human breast cancer and melanoma cells

Increased expression of autotaxin in tumors including glioblastoma, breast, renal, ovarian, lung, and thyroid cancers is associated with increased tumor aggressiveness. Autotaxin promotes metastasis as well as cell growth, survival, and migration of cancer cells. These actions could depend on the noncatalytic effects of autotaxin on cell adhesion, or the catalytic activity of autotaxin, which converts lysophosphatidylcholine into lysophosphatidate in the extracellular fluid surrounding the tumor. Both lysophosphatidylcholine (LPC) and lysophosphatidate have been reported to stimulate migration through their respective G‐protein coupled receptors. The present study determines the roles of autotaxin, LPC, and lysophosphatidate in controlling the migration of two cancer cell lines: MDA‐MB‐231 breast cancer cells, which produce little autotaxin and MDA‐MB‐435 melanoma cells that secrete significant levels of autotaxin. LPC alone was unable to stimulate the migration of either cell type unless autotaxin was present. Knocking down autotaxin secretion, or inhibiting its catalytic activity, blocked cell migration by preventing lysophosphatidate production and the subsequent activation of LPA_1/3 receptors. We conclude that inhibiting autotaxin production or activity could provide a beneficial adjuvant to chemotherapy for preventing tumor growth and metastasis in patients with high autotaxin expression in their tumors. © 2009 Wiley‐Liss, Inc.