总粉尘浓度转换为呼吸性粉尘浓度的两种方法学研究

目的探讨流行病学研究中历史性总粉尘浓度转换成呼吸性粉尘浓度的理论方法。方法采用两种方法：一种通过体积直接计算;另一种用ＨａｔｃｈＣｈｏａｔｅ方程计算,推导出计数百分比和计量百分比的转换关系。结果得到总粉尘浓度与呼吸性粉尘浓度的理论转换系数,其中,用ＨａｔｃｈＣｈｏａｔｅ方程计算结果偏低。结论体积直接计算法更适用。     

Experimental intrahepatic portacaval anastomosis: use of expandable Gianturco stents

Original Gianturco expandable stents and their modifications were used to create an experimental intrahepatic portacaval anastomosis (EIPCA) in 30 young domestic swine without portal hypertension. The study focused on the design of a suitable stent, the technique of its application, and the evaluation of short-term patency of the EIPCA. A stent with a 2.5-cm-long body and wire skirts on both ends was most suitable for EIPCA creation. Well-positioned stents shunted most of the portal blood in the inferior vena cava circulation and remained patent for 4-6 weeks. Ingrowth of liver parenchyma and abundant proliferation of the intima and connective tissue inside the stent lumen in these rapidly growing animals gradually decreased EIPCA patency, and thrombus formation with diminished blood flow closed them completely.     

Conservative surgery for atrioventricular valve myxoma.

Patients with valvular myxoma are usually candidates for surgery because of the high incidence of life-threatening embolism. In some cases, the tumor is sessile or presents with a large peduncle: complete excision may then lead to valve replacement. We report two cases of atrioventricular valve myxoma where replacement was avoided. In one patient, a mitral myxoma appended from the edge of the anterior leaflet close to the chordae insertion; safe excision implied destruction of the two chordae and a peritumoral section of the anterior leaflet. A chordal transposition technique was used to preserve valve competence. In a second patient, a tricuspid myxoma causing syncopal episodes was resected; this was characterized by a large stalk, located on the anterior tricuspid leaflet away from chordal attachment and the valvular annulus. Treatment was by resection and the leaflet reconstructed with a pericardial patch. Techniques for conservative treatment of degenerative valvular disease or endocarditis, when monitored peroperatively by transesophageal echocardiography, may be successful in the surgical resection of atrioventricular myxoma.     

Plantar fibromatosis: ultrasonography results]

INTRODUCTION: Plantar fibromatosis, or Ledderhose's disease, is a fibrous proliferation arising within the plantar fascia end exhibiting typical clinical nodular features. The lesion appears as a firm single thickening or a nodule, occasionally painful, localized to the medial portion of the sole of the foot. This unusual condition has not been extensively studied with US and very little has been written about it. MATERIAL AND METHODS: In 1998-99, six patients with plantar fibromatosis were submitted to US with 13 MHz linear array and 20 MHz mechanical annular array probes. All patients were examined in prone recumbency with the probe positioned on the sole of the foot. Only some of them were subsequently submitted to surgery. RESULTS: Plantar fibromatosis exhibited an almost pathognomonic pattern and US proved to be a quick, noninvasive and cost-effective technique to confirm clinical diagnosis. The nodule is typically single and isoechoic, with maximum diameter of about 1 cm, inhomogeneous internal structure and few thin hyperechoic septa. The nodular fibrous proliferation adheres with the major axis along the plantar fascia; it exhibits clear-cut margins and US beam transmission is good. No calcifications or fluid collections are seen within the nodule. Color and power Doppler show no flow inside. CONCLUSIONS: US is an adequate tool for the study of plantar fibromatosis.     

Methodologic and compliance issues in postcoronary bypass surgery subjects

Persons who engage in preventive health behaviors may reduce the progression of coronary artery disease. The immediate objective of this pilot study was to assess adherence to behavioral lifestyle changes in patients after coronary artery bypass graft surgery by analyzing self-reported responses using objective measures. Data on adherence to diet, exercise, and smoking were collected from questionnaires completed by each subject. Carbon monoxide index, serum cholesterol, pre- and postambulatory pulse rates, and pre- and post-stair-climbing pulse rates were measured. All tests were conducted before discharge and at a one-month follow-up visit. Analysis of objective data showed a statistically significant reduction in total serum cholesterol, decreased smoking behavior, and increased ambulation from before discharge to one-month follow-up. Analyses showed that self reports of adherence to diet, activity, and smoking cessation were consistent with objective measures in at least 50% of subjects. Serial objective measures provide valuable indicators of patient adherence and assist staff in developing individually tailored patient education.     

Septicemia and endocarditis caused by group G streptococci in a Norwegian hospital

The clinical and bacteriological features of septicemia caused by group G streptococci were analyzed in nine patients seen during a period of 28 months. Four of these patients had acute endocarditis with a high rate of serious neurological complications. The clinical response to antibiotic treatment was slow in the endocarditis patients despite sensitivity of the organism in vitro. Group G streptococcal septicemia can be a very serious condition associated with endocarditis of a destructive nature. Comparison with previous reports suggests that group G streptococcal infections are of increasing importance. The virulence of group G streptococci may be changing, resulting in more serious infections and complications. This series stresses the importance of prompt recognition of this infection and the need for aggressive management of these patients.