Surface permeability and degradation of dental composites resulting from oral temperature changes

The surface changes in dental composites caused by thermal cycling and different temperatures were evaluated by use of silver nitrate to stain the surface layers. Rapid temperature change resulted in the formation of layers within the surface which may have resulted from microcracking. Slow rates of change increased the depth and rate of diffusion of silver nitrate. Determination of the temperature changes at the surface of a restoration in the mouth indicated that in vivo temperature change is more likely to increase the depth of diffusion of oral fluids than to cause microcracking of the surface.     

The use of objective digital matching to achieve an esthetic composite restoration

OBJECTIVE: To investigate the ability to match composite restorations to teeth using digital imaging and CIE L*a*b* color differences. METHODS: Ten extracted human central incisors were used. Eleven discs of composite of differing shades were produced and mounted on white cardboard to create a customized shade guide (CSG). The CSG was photographed next to each of the ten teeth in a phantom head using a digital SLR camera. The images were analyzed, and color differences (deltaE) between the teeth and the shade discs were calculated using CIE L*a*b* values. Three cavities were then drilled into the labial surface of each tooth. Composite shades with the lowest three deltaE values were then used to restore the cavities. Ten observers evaluated the teeth under a standard D65 light source and recorded the best match. RESULTS: The majority of the observers selected the lowest deltaE in six out of the 10 teeth, and in a further two out of 10 teeth the second lowest deltaE was chosen. CONCLUSION: The lowest deltaE selected by objective color matching was agreed as the best match by observers. The high correlation between digital and visual color matching confirms the ability of digital camera and image analysis software to detect color differences.     

Monitoring for undertransfusion

BACKGROUND: Most published reviews and audits of blood and blood component transfusion have focused on the issue of overtransfusion and on the inappropriate use of red cell components. There is growing concern that efforts to curb unnecessary transfusions may result in a trend toward undertransfusion of patients. There is little published information that addresses this issue or the magnitude of this practice. STUDY DESIGN AND METHODS: Undertransfusion was evaluated by examining the transfusion records from a 3-month period for 55 patients who met the study criteria of having either a hemoglobin level < 7 g per dL or a platelet count of < 10 × 10(9) per L. If the identified patient did not receive a transfusion within 24 hours of the reported hemoglobin level or platelet count, the medical record was reviewed by a resident physician. RESULTS: A total of 213 individual hemoglobin levels and platelet counts, representing the 55 patients, met our transfusion criteria. All except 8 of the identified patients received red cells and/or platelet transfusions. Reasons for not transfusing red cells included the patient's response to nutritional support and iron supplementation, refusal of blood, and noncompliance. Reasons for not transfusing platelets included falsely low platelet count because of platelet clumping in vitro, contraindication based on clinical diagnosis (e.g., immune thrombocytopenic purpura), and the patient's death before transfusion. CONCLUSION: Red cell and platelet transfusions were appropriately ordered for all patients who met the transfusion criteria. Undertransfusion is not a problem at this institution according to the criteria established. It is recommended that other institutions expand their blood utilization audits to include investigation for evidence of undertransfusion. Further research regarding the issue of undertransfusion is warranted and could be expanded to include other components.     

Analytical and clinical evaluation of the Bayer ADVIA Centaur automated B-type natriuretic peptide assay in patients with heart failure: a multisite study

BACKGROUND: B-Type natriuretic peptide (BNP) is released from the left ventricle of the heart into the circulation in response to ventricular stretching and volume overload. Increased BNP concentrations are associated with heart failure (HF). METHODS: We evaluated the analytical and clinical performance of the Bayer ADVIA Centaur BNP assay. Studies included precision, analytical correlation (against the Shionogi ShionoRIA and Biosite Triage BNP assays), BNP results for blood collected in plastic tubes containing EDTA vs other collection tubes, high-dose hook effect, detection limits, and interferences. The clinical performance was tested on 2243 blood samples collected from 983 apparently healthy individuals, 538 patients with chronic disease but without HF (renal insufficiency, chronic obstructive pulmonary disease, diabetes, and hypertension), and 722 patients with HF (New York Heart Association classes I-IV). RESULTS: The ADVIA Centaur assay had total imprecision (CV) of 3.4%, 2.9%, and 2.4% at BNP concentrations of 48, 461, and 1768 ng/L, respectively. The Passing-Bablok correlations to the ShionoRIA and Triage were as follows: ADVIA Centaur = 1.11(ShionoRIA) - 1.19 ng/L (r = 0.98); ADVIA Centaur = 0.78(Triage) + 5.89 ng/L (r = 0.92), respectively. Of the different blood collection tubes, only EDTA plastic tubes (with and without the barrier gel) were acceptable. The lower detection limit was 0.5 ng/L, and there were no interferences from common analytes, other neuropeptides, or unusual antibodies. BNP exhibited different reference intervals according to age and gender. BNP concentrations increased progressively as the severity of HF increased. CONCLUSIONS: The ADVIA Centaur is the first commercially available BNP assay for use on an automated immunochemistry platform. This assay has good analytical and clinical performance characteristics for diagnosing HF.     

N-Chlorotaurine Exhibits Fungicidal Activity against Therapy-Refractory Scedosporium Species and Lomentospora prolificans

N-Chlorotaurine (NCT), a well-tolerated endogenous long-lived oxidant that can be applied topically as an antiseptic, was tested on its fungicidal activity against Scedosporium and Lomentospora, opportunistic fungi that cause severe infections with limited treatment options, mainly in immunocompromised patients. In quantitative killing assays, both hyphae and conidia of Scedosporium apiospermum, Scedosporium boydii, and Lomentospora prolificans (formerly Scedosporium prolificans) were killed by 55 mM (1.0%) NCT at pH 7.1 and 37°C, with a 1- to 4-log₁₀ reduction in CFU after 4 h and a 4- to >6-log₁₀ reduction after 24 h. The addition of ammonium chloride to NCT markedly increased this activity. LIVE/DEAD staining of conidia treated with 1.0% NCT for 0.5 to 3 h increased the permeability of the cell wall and membrane. Preincubation of the test fungi in 1.0% NCT for 10 to 60 min delayed the time to germination of conidia by 2 h to >12 h and reduced their germination rate by 10.0 to 100.0%. Larvae of Galleria mellonella infected with 1.0 × 10⁷ conidia of S. apiospermum and S. boydii died at a rate of 90.0 to 100% after 8 to 12 days. The mortality rate was reduced to 20 to 50.0% if conidia were preincubated in 1.0% NCT for 0.5 h or if heat-inactivated conidia were used. Our study demonstrates the fungicidal activity of NCT against different Scedosporium and Lomentospora species. A postantifungal effect connected with a loss of virulence occurs after sublethal incubation times. The augmenting effect of ammonium chloride can be explained by the formation of monochloramine.     

First Report of an Acute,Obstructive Thrombosis of a Melody Valve Used for Transcatheter Pulmonary Replacement

Transcatheter pulmonary valve (TPV) replacement is an effective therapy of right ventricular outflow tract conduit dysfunction. Acute complications after TPV implantation include infective endocarditis, stent fracture, and device dislocation. We present a novel, life-threatening complication: an acute, noninfectious TPV thrombosis. Within 24 hours after implantation of a Melody system (Medtronic, Inc, Minneapolis, MN), the patient developed an acute TPV thrombosis characterized by severe TPV stenosis on echocardiography and contrast filling defects on computed tomography pulmonary angiography images. Genetic testing revealed heterozygous prothrombin G20210A polymorphism and homozygous 4G/4G polymorphism of the plasminogen-activator-inhibitor. The patient recovered after surgical valve replacement with a pulmonary homograft.