Mechanism of mosaic attenuation of the lungs on computed tomography in induced bronchospasm

The purpose of this study was to investigate whether hypoxic pulmonary vasoconstriction is the major determinant of the computed tomography (CT) pattern of mosaic attenuation in asthmatic patients with induced bronchoconstriction. Thin-section CT was performed at suspended full inspiration immediately and 30 min after methacholine bronchoprovocation in 22 asthmatic subjects, who were randomly assigned to breathe room air (group A, n = 8), oxygen via nasal prongs at 5 l/min (group B, n = 8), and oxygen via face mask at 12 l/min (group C, n = 6). CT changes were quantified in terms of global lung density and density in hypodense and hyperdense areas. Lung parenchymal density increases were greatest in group C and greater in group B than in group A, globally (P = 0.03) and in hypodense regions (P = 0.01). On bivariate analysis, the only change in cross-sectional area was related to change in global density. In hypodense regions, density change was related both to reduction in cross-sectional area (P < 0.0005) and to oxygen administration (P = 0.01). After correction for changes in global lung density, only oxygen was independently related to density increase in hypodense areas (P = 0.02). In induced bronchoconstriction, the CT appearance of mosaic attenuation can be largely ascribed to hypoxic vasoconstriction rather than to changes in lung inflation.     

Effect of chemotherapy on the larval mass and the long-term course of alveolar echinococcosis. Swiss Echinococcosis Study Group

The efficacy of long-term chemotherapy in nonresectable alveolar echinococcosis is debated, particularly because of the difficulty in defining therapeutic success. In this study the effect of chemotherapy on the parasitic mass was evaluated in a series of 37 patients. The patients had larval lesions documented by serial computed tomography studies at least 1.5 yr after chemotherapy (mean = 6.4 yr, range = 1.5 to 10.7 yr). The therapeutic regimen consisted of mebendazole (n = 34) or albendazole (n = 3) as previously described. The maximal areas of the parasitic lesions were assessed morphometrically by means of digital image analysis, utilizing the point-integration method, before and after chemotherapy. Marked regression of larval tissue occurred in 18 patients (group A; 48.6%), stationary lesions were noted in 13 patients (group C; 35.1%) and progression was found in 6 patients (group B; 16.2%). The three groups did not differ significantly with regard to age, plasma drug levels, duration of chemotherapy or initial size and composition of lesions (e.g., cystic cavities, degree of calcification). Despite morphologically successful chemotherapy in moist patients (e.g., 84%; groups A and C), late cholestatic complications after 1.5 to 11 yr of chemotherapy occurred in 10 patients (group A, n = 7; group C, n = 3; 4 of them died) and esophageal variceal bleeding occurred in 3 patients (relieved by sclerotherapy). These late complications were probably mainly due to posttherapy fibrosis of hilar structures. In conclusion, our data support the efficacy of chemotherapy. However, chemotherapy is not curative, and severe late complications were observed in patients with hilar (fibrotic) involvement.     

An evaluation of a model ecosystem with DDT

The reproducibility, variability, and reliability of a simple aquatic-terrtestrial model ecosystem experiment was tested with p,p'-DDT. The variation among the model replicates as well as within the units was studied by using hierarchal analysis of variance. the complete budget of the chemical was calculated and a theoretical transport model was constructed. The degradation and accumulation of DDT was followed by gas chromatographic residue analysis, which showed good reproducibility of the experimental design. The degradation of DDT in the model was similar to that found in the field, but the determination of concentration factors was questionable. The material balance tables revealed that the soil and bottom substrates were the main contributors, which regulated the fate of the chemical in the model. The usefulness of the model is presented in this report.     

裸光纤光栅及光纤力锤在大桥模型试验中的应用

经缩尺比例后,大跨度悬索桥模型的构件一般变得很细小,尺寸大的传感器无法或不宜安装在结构模型上,尤其是需作动力试验的模型,附加大量传感器及电缆线的质量、刚度和阻尼会严重影响试验的结果.为解决此问题,该文采用细柔的裸光纤光栅测量直径仅0.5mm细钢丝吊索及其他细小构件的应变.为获得光纤所测应变的传递函数,研制了激振用的光纤...     

Characterisation of bioactive glass coatings on titanium substrates produced using a CO2 laser

Titanium and its alloys are widely used in load-bearing bioinert implants. Bioactive glasses (BAGs) form a chemical bond with bone, but they are not suitable for load-bearing applications. Creating a BAG coating on a titanium implant could combine the best properties of both materials. The results tend to be poor when conventional firing methods are applied to coat titanium with BAG. A local application of heat to melt the glass can be achieved by a CO2 laser. A new method is introduced to create BAG coatings on titanium locally in a controlled manner, with a focused CO2 laser beam. The coatings produced by this method precipitate calcium phosphate in vitro. Processing parameters (number of coated layers, laser power, and processing atmosphere) providing a firm attachment of the glass and good in vitro bioactivity were identified. XRD analysis showed no crystallisation of the glass due to processing with the laser. EDXA indicated the formation of a calcium phosphate layer, which FTIR suggested to be a hydroxyapatite. The results show CO2 laser processing to be a promising technique for the manufacture of 30-40 microm BAG coatings on titanium.     

Phase II trial of docetaxel: a new, highly effective antineoplastic agent in the management of patients with anthracycline-resistant metastatic breast cancer

PURPOSE: To determine the efficacy (objective response rate and duration of response and survival) and toxicity of docetaxel in patients with strictly defined anthracycline-resistant metastatic breast cancer (MBC). PATIENTS AND METHODS: Thirty-five patients with bidimensionally measurable MBC who had progressive disease while receiving anthracycline-containing chemotherapy were registered onto the phase II trial. Docetaxel was administered at a dose of 100 mg/m2 over 1 hour every 21 days. RESULTS: Thirty-four patients were assessable for disease response; 18 (53%; 95% confidence interval [CI], 35% to 70%) achieved a partial response. The median times to disease progression and survival duration were 7.5 and 13.5 months, respectively, for responding patients. The median overall survival duration was 9 months. Two hundred eight cycles (median, five) of docetaxel were administered. Neutropenia with less than 500 cells/microL developed in 31 of 35 patients; it was complicated by fever in 30 (14%) of 208 cycles and in 18 (51%) of 35 patients, including one treatment-related death. Fluid retention was seen in 15 (43%) of 35 patients, including pleural effusions in 11 patients (31%). Moderate skin toxicity, asthenia, and myalgia were observed in 16%, 58%, and 37% of cycles, respectively. CONCLUSION: Docetaxel has the highest reported antitumor activity in anthracycline-resistant MBC. High objective response rates were seen in patients with visceral-dominant involvement, multiple metastatic sites, or extensive previous therapy. Docetaxel is associated with severe but reversible neutropenia, asthenia, and cumulative dose-related fluid retention. Dexamethasone decreased the frequency and severity of skin toxicity and appeared to ameliorate fluid retention.