ABSTRACT
Risk of infection with leptospirae during farmwork was estimated using information from past leptospirosis outbreaks in both Miyagi Prefecture, Japan (around 1960) and northeastern Thailand (around 2000). Outbreaks of leptospirosis in Miyagi Prefecture were concentrated in October, while it occurred throughout the rainy season, showing a tendency to decentralize, in northeastern Thailand. In 1959, a large leptospirosis outbreak occurred in Miyagi Prefecture. The risk (1,600/100,000) of leptospira infection in the high-risk area during that outbreak was 3.4 times as high as that (470/100,000) in the middle-risk area. The risk in this year was 5.7 (high-risk area), 2.8 (middle-risk area) and 2.0 (low-risk area) times higher than that in the same area from 1960 to 1964 which could be considered as the average risk in the past time. In northeastern Thailand, the risk (50/100,000) of leptospira infection was 30 percent compared with that (170/100,000) in the middle-risk areas in Miyagi Prefecture from 1960 to 1964. Based on the risk, number of leptospirae invading into human body through skin during farmwork was estimated with the dose-response model. In Miyagi Prefecture and northeastern Thailand, the estimated numbers were 65-1,200 and 3.5-42 leptospirae per 100,000 exposures which means frequency of the daily farmwork, respectively. On the other hand, the calculation under possible environmental conditions (e.g. density of rats carrying leptospirae, water depth in paddy field) demonstrated that farmers had been in contact with 4,300 leptospirae only in an hour of their work. The result showing only a small part of leptospirae in contact invaded into human body primarily attributes to the strong structure of unwounded skin composed of stratified squamous epithelium and dermis. And also the result can be explained by a hydraulics theory. Although leptospirae being nearby skin surface can attach to skin since the water flow does not occur there, the spirochetes a little away from skin surface are easily transported with the flow and would be unable to invade into human body.
ABSTRACT
Thromboembolic events after cardiac surgery, including ischemic strokes, can be devastating complications, however only a few studies manifest the platelet activation and coagulation state after off-pump coronary artery bypass (OPCAB). Platelet-derived microparticles (PMP) are observed as released vesicles from platelets following platelet activation, and are believed to play a role in some clinical diseases because of their procoagulant activity. The aim of the present study was to evaluate the hypercoagulant state after OPCAB using PMP and other indices. Data were obtained from 15 patients (aged 69±7 years; only men) undergoing elective OPCAB surgery. One hundred milligrams of aspirin were used as postoperative antiplatelet drugs. Preoperative risk factors, operation time, postoperative hospital stay, transfusion and blood samples of CBC, PMP, βTG, PF 4, platelet aggregation, FDP, D-dimer and TAT of pre- and postoperative days (POD) 3 and 7 were studied. There was no difference between the PMP level with or without risk factor. The PMP levels of POD 3 and 7 were significantly higher compared to the preoperative levels (pre-op, POD 3, 7:9.1±5.1, 15.2±10.3, 28.4±24.5/10<sup>4</sup>plt respectively, <i>p</i><0.05). The levels of FDP, D-dimer and TAT rose significantly on POD 3 and 7 and significantly correlated with the PMP levels. Beta TG, PF 4 and platelet aggregation did not change after OPCAB surgery, and no correlation was found with the PMP levels. Elevated levels of PMP, TAT, FDP and D-dimer persisted until POD 7 and suggested not only platelet activation, but also activation of the coagulation and fibrinolytic system. The findings suggest that 100mg of aspirin may not be adequate for the inhibition of platelet activation after OPCAB surgery.