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Biomedical subjects

Y H Dai

Publications and source records attributed to Y H Dai.

14 recordsLinked to original sources
PubMed2000

Possible effects of the Three Gorges dam on the transmission of Schistosoma japonicum on the Jiang Han plain, China.

The Three Gorges dam, under construction on the Yangtze River in China, might affect the transmission of Schistosoma japonicum on the Jiang Han plain, which is downstream of the dam. To study this possibility, the prevalence of schistosomiasis was investigated in relation to a range of malacological, hydrological and meteorological factors. The general water level in the Yangzte over a year had a marked effect on the distribution of the intermediate host (Oncomelania hupensis) and the prevalence of human schistosomiasis in that year. Disease prevalence showed significant correlations with the density of the snail hosts, the level of the water table, annual rainfall, yearly evaporation, and altitude. Once the dam is complete, the flow of water downstream will probably be maintained at a level between those currently occurring in flood and dry weather, and this may have implications for schistosome transmission. Systematic monitoring is necessary to investigate the impact of the environmental changes brought about by the dam on transmission.

Altitude↗
PubMed2000

[Reconstruction acusticus back wall and tympanoplasty with homograft costal cartilage].

OBJECTIVE: To eliminate the back wall defect of external canal and opened mastoid cavity which was remained from radical mastoidectomy. METHOD: We performed the operation on 17 cases after radical mastoidectomy by using reconstruction of the canal wall and fill-in opened mastoid cavity and ossicular replacement prostheses made of homograft costal cartilage. The tympanoplasty had been made operated for all patients, 8 ears were PORP, the others were TORP. RESULT: All cases were followed-up for 6 months-2 years. The external canal of all patients are normal in appearance. The total effective rate of gain (> 15 dB) was 14 ears (82.4%). Only one patient whose tympanic membrane was perforated postoperation 3 months. CONCLUSION: Reconstruction of acusticus back wall and hearing after radical mastoidectomy with homograft costal cartilage is effective to prevent mastoid cavity infection and improve hearing.

Adult↗
PubMed1999

Impact of environmental change and schistosomiasis transmission in the middle reaches of the Yangtze River following the Three Gorges construction project.

With the construction of the Three Gorges high dam on the Yangtze River in China in mind, a serious of ecological environmental factors that might affect the transmission of Schistosoma japonicum in Jian Han Plain were investigated by means of data collection, field surveys and observation in Hubei Province. Several ecological factors including water level of the Yangtze River; riparian water table, annual rainfall and yearly evaporation were investigated in relation to the prevalence of schistosomiasis. The results suggest that after the dam construction, middle water level flows (ie between flood flows and dry-weather flows) will persist in the flood season due to a rise in the water table. The investigation indicated that snail distribution and human schistosomiasis prevalence differed significantly between years which had typically high, middle and low typical water levels in the Yangzte. Moreover, the prevalence of the disease showed a significant linear regression relationship with density of snail intermediate hosts, water table, annual rainfall, yearly evaporation and ground altitude in the survey area. Systematic and careful monitoring and surveillance is necessary to investigate the impact of the environmental changes brought about by the dam construction on schistosomiasis transmission.

Animals↗
PubMed1997

Patterns and determinants of use of antibiotics for acute respiratory tract infection in children in China.

BACKGROUND: Use of antibiotics for acute respiratory infection (ARI) of presumed viral etiology is a worldwide problem. The World Health Organization (WHO) has provided guidelines for diagnosis and treatment of ARI for developing countries. METHODS: Specially trained observers applied the WHO criteria to study the diagnosis and treatment of ARI given by 100 randomly selected health care workers (HCWs) in a rural county in China. A total of 750 cases of ARI were evaluated. RESULTS: Before the parents sought medical care, 47% of children in the county hospitals, 25% of those in the townships and 18% of those in the villages had already received antibiotics, available without prescription. Among the HCWs antibiotic abuse (antibiotics for presumably viral disease) was detected in the treatment of 97% of cases, and severe abuse (such as prescription of two incompatible antibiotics) was detected in 37%. Most (197 of 200) patients with bacterial disease received antibiotics, but inappropriate antibiotic treatment (dose or type) was observed in 63% of these cases. HCWs with university training and those with higher test scores on knowledge and attitude prescribed antibiotics more judiciously than those lacking those attributes. CONCLUSIONS: Abuse of antibiotics for ARI is a serious and costly problem in rural China, potentially leading to widespread antibiotic resistance. Educating HCWs in the management of ARI and proper use of antibiotics has high priority in China.

Acute Disease↗
PubMed1984

Significance of increased lung thallium-201 activity on serial cardiac images after dipyridamole treatment in coronary heart disease.

Increased lung thallium-201 (Tl-201) activity occurs in patients with severe coronary artery disease (CAD) on initial postexercise images. To determine the significance of assessing lung Tl-201 on serial imaging after dipyridamole therapy, initial and delayed (2 to 3 hours) Tl-201 imaging was performed in 40 patients with CAD and 26 normal control subjects. Lung Tl-201 activity was quantitated as a percentage of maximal myocardial activity for each imaging time (lung Tl-201 index). The mean initial lung Tl-201 activity was 42 +/- 2% (+/- standard error of the mean) in 26 control subjects, 56 +/- 2% in 25 patients with 2- or 3-vessel CAD (p less than 0.001) and 53 +/- 2% in 15 patients with 1-vessel CAD (p less than 0.005 compared with control subjects) (difference not significant between 1-vessel and multivessel CAD). Dipyridamole lung Tl-201 activity decreased relative to the myocardium from initial to delayed images (p less than 0.001) in patients with CAD but not in control subjects. When a dipyridamole lung Tl-201 index of 58% (mean +/- 2 standard deviations for control subjects) was chosen as the upper limit of normal, 14 of 40 of the CAD patients (35%) had abnormal values and all control patients had values within normal limits. These 14 patients with CAD and abnormal initial lung Tl-201 indexes had rest ejection fractions that were not significantly different from those in patients with CAD, and normal initial dipyridamole lung Tl-201 index (58 +/- 4% and 63 +/- 2%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Serial thallium-201 imaging after dipyridamole for coronary disease detection: quantitative analysis using myocardial clearance.

After dipyridamole, canine studies have demonstrated a slower rate of myocardial thallium-201 clearance from zones distal to a coronary artery stenosis compared to normal zones. To determine if criteria based on canine myocardial thallium-201 clearance rates could be applied clinically, 40 patients with and 26 patients without coronary artery disease (CAD) had serial thallium-201 images obtained for 2 to 5 hours after dipyridamole. Regions of interest were manually placed over six left ventricular segments in two projections for each of three imaging times. The myocardial thallium-201 clearance rate was calculated for each of the six segments and, using the clearance rate criterion found in canine studies, was considered abnormal if less than 6.5%/hr. Using this criterion alone, 22 of 26 patients (85%) without CAD had normal and 30 of 40 patients (75%) with CAD had abnormal myocardial thallium-201 clearance rates. A quantitative analysis of regional inhomogeneity in tracer distribution (normal was greater than or equal to 25% difference between segments) was negative in 24 of 26 patients (92%) without CAD and positive in 20 of 40 patients (50%) with CAD. When both clearance rate and regional inhomogeneity were considered, 21 of 26 patients (81%) without CAD had negative and 36 of 40 patients (90%) with CAD had positive results. Thus, post-dipyridamole myocardial clearance rate criteria derived from canine studies can be applied to clinical thallium imaging. Quantitative analysis of serial thallium-201 images after dipyridamole is optimized by using myocardial thallium-201 clearance rates. Such an approach is independent of regional inhomogeneities in tracer distribution.

Adult↗