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熵代表无序的水平,作者使用通气的熵变(ECV)指示肺通气的不均匀性,ECV定义为当前泡潮气量趋近于零时每摩尔被吸入气体从不均匀通气到均匀通气的熵变的极限。本文从熵的基本公式民地出ECV的计算方程。用几个数学模型肺将ECV同其他7个洗出指标进行了比较。8个指标中,只有ECV仅取决于通气分布,其他7个指标不仅取决于通气分布,还同潮气量和死腔的大小有关。这影响了它们评价肺通气不均匀性的效果,ECV的另一  相似文献   
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Treatment of non-seminomatous testicular cancer often leadsto infertility due to anejaculation/retrograde ejaculation andpoor sperm quality. In these men spermatozoa may be obtainedby transrectal electroejaculation (TE), but the optimal strategyfor assisted procreation in these couples is not known. Ouraim was to examine whether TE and conventional in-vitro fertilization(IVF) would be successful. A total of 10 couples, with long-standinginfertility due to anejaculation or retrograde ejaculation aftertreatment for testicular cancer 5–14 years earlier, werereferred to our unit. All men underwent diagnostic TE undergeneral anaesthesia. Spermatozoa were recovered in nine cases.The antegrade fraction was prepared and used for IVF. Spermquality was variable and conventional IVF was considered impossiblein three cases. Altogether six IVF treatment cycles in six couplesresulted in five pregnancies, of which four resulted in a deliveryand one resulted in a spontaneous abortion. One additional pregnancyis ongoing after transfer of cryopreserved embryos. The fertilizationrate was 54% (33/61) and the cleavage rate was 97% (32/33).No complications relating to the procedure have been encountered.  相似文献   
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Abstract The inflammatory response of immune cells to target cells and cell-matrix molecules is regulated by several receptor-ligand molecules. As fibrosis develops in ongoing chronic rejection after liver transplantation, it is of interest to analyze patterns of integrin receptors and cell-matrix molecules in order to study the relation between immune cells and the stromal and parenchymal cells. In the present study, we demonstrated the expression of these molecules in chronic rejected human liver grafts using immunohistochemical techniques. The results showed a differential expression and induction of integrin receptors and cell-matrix molecules on resident liver cells, especially on sinusoids, reflecting a state of chronic inflammation and a specific interaction between integrin receptors and cell-matrix molecules. The patterns of induced integrin receptors on graft-infiltrating cells was closely related to the local production of cell-matrix molecules and reflected the final sequence of a stepwise progress of the inflammatory reaction.  相似文献   
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OBJECTIVES--To assess the risk of cancer, especially leukaemia, in a cohort of sterilant workers exposed to ethylene oxide (EtO). METHODS--A cohort of 2170 workers employed for at least one year in two plants that produce disposable medical equipment sterilised with EtO has previously been established. The results of an update with four more years of observation are presented. The cancer incidence was assessed for the periods 1976 to 1990 and 1972 to 1990 and cause specific standardised incidence ratios (SIRs) were calculated. Individual cumulative exposure to EtO, expressed as ppm-years, was estimated and used in exposure-response analyses. RESULTS--Six lymphohaematopoietic tumours were observed (SIR 1.78, 95% confidence interval (95% CI) 0.65-3.88), of which two were leukaemias (SIR 2.44; 95% CI 0.30-8.81). When those with cumulative exposures to EtO below the median value (0.13 ppm-years) were excluded, and a minimum of 10 years induction latency period was applied, the incidence ratio for leukaemia increased further (SIR 7.14, 95% CI 0.87-25.8), but was still not significantly enhanced. CONCLUSIONS--The risk estimate for leukaemia increased, but non-significantly, with time since start of exposure, and with cumulative exposures to EtO above the median value. The subjects with leukaemia had, however, only slightly higher cumulative exposure estimates for EtO than the average cohort member. Nevertheless, the present results may add some minor evidence for an association between EtO and an increased risk of leukaemia.  相似文献   
6.
OBJECTIVES--To examine the mortality pattern and the cancer incidence in a cohort of long term smelter workers exposed to lead. METHODS--The cohort consists of 664 male lead battery workers, employed for at least three months in 1942-87. From 1969 the values of all blood lead samples repeatedly obtained from these workers every two to three months, have been collected in a database. The expected mortality and morbidity 1969-89 was estimated from the county rates, specified for cause, sex, five-year age groups, and calendar year. Individual exposure matrices have been calculated and used for dose-response analyses. RESULTS--The total cohort showed an increased overall mortality (standardised mortality ratio (SMR) 1.44; 95% confidence interval (95% CI) 1.16-1.79), an increased mortality from ischaemic heart diseases (SMR 1.72; 95% CI 1.20-2.42) and all malignant neoplasms (SMR 1.65; 95% CI 1.09-2.44). These risk estimates were unaffected or slightly decreased when applying a latency period of 15 years, and no dose-response pattern was shown. The non-significantly raised cancer incidence in the gastrointestinal tract (11 malignancies) in the total cohort, increased to a barely significant level in the quartile with the highest cumulative lead exposure (standardised incidence ratio (SIR) 2.34, 95% CI 1.07-4.45). No clear dose response pattern was evident when further subdividing the data into those first employed up to 1969 v those first employed after 1969 when the blood lead monitoring programme started. The risk estimate for malignancies in the gastrointestinal tract was not related to latency time. The cancer incidence was not increased at other sites. CONCLUSIONS--A slightly increased incidence of gastrointestinal cancers was found in workers exposed to lead and employed before 1970. The lead cohort also showed an increased mortality from ischaemic heart diseases. These risk estimates did not show a dose-response pattern and were not associated with latency time. The results must also be interpreted with caution because of limited numbers, and lack of dietary and smoking data.  相似文献   
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Using multiple PCR primer sets, we tried to optimize the detection of human papillomavirus (HPV) in DNA samples isolated from 361 frozen biopsy specimens from patients with invasive cervical carcinomas. The HPVs detected were placed into three distinct groups, including group I/Inex at Telelab (Skien, Norway) and group Ineg and group II at the Norwegian Radium Hospital (Oslo, Norway). The consensus primer sets were Oli-1b-oli-2i, My09-My11, Gp5-Gp6, and Gp(5+)-Gp6+ from the HPV L1 gene and CpI-CpIIG from the E1 gene. Using these consensus primers together with the type-specific primers from E6-E7, we found that 355 patients (98%) were HPV positive. Type-specific primers for HPV types 11, 16, 18, 31, 33, and 35 detected more HPV-infected patients than the most sensitive consensus primer set, while the three consensus primer sets My, Gp/Gp+, and Cp together detected more HPV-positive patients than the type-specific primers. Testing of sensitivity of the PCR with SiHa cells serially diluted in lymphocytes (HPV-negative cells) indicated a detection limit of 6,300 HPV type 16 DNA copies with consensus primers (My, Gp+, and Cp) and 126 original HPV type 16 DNA copies with type-specific primers. Comparison of the amplification results for consensus L1 primers and type-specific E6-E7 primers indicated the presence of L1 deletions in 23 of 56 samples. The conclusion is that in PCR detection systems, multiple consensus primers and type-specific primers should be used in order to detect all patients harboring HPV.  相似文献   
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Background

Cardiovascular disease (CVD) risks are of concern among immigrants and refugees settling in affluent host countries. The prevalence of CVD and risk factors among Somali African immigrants to the U.S. has not been systematically studied.

Methods

In 2015–2016, we surveyed 1156 adult Somalis in a Midwestern metropolitan area using respondent-driven sampling to obtain anthropometric, interview, and laboratory data about CVD and associated risk factors, demographics, and social factors.

Results

The prevalence of diabetes and low physical activity among men and women was high. Overweight, obesity, and dyslipidemia were also particularly prevalent. Levels of calculated CVD risk across the community were greater for men than women.

Conclusion

Though CVD risk is lower among Somalis than the general U.S. population, our results suggest significant prevalence of risk factors among Somali immigrants. Comparison with prior research suggests that CVD risks may be increasing, necessitating thoughtful intervention to prevent adverse population outcomes.

  相似文献   
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