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91.
92.
Increased concentrations of octachlorodibenzo-p-dioxin in cases with breast cancer--results from a case-control study 总被引:1,自引:0,他引:1
L Hardell G Lindstr?m G Liljegren P Dahl A Magnuson 《Canadian Metallurgical Quarterly》1996,5(5):351-357
Organochlorines are persistent and highly lipophilic environmental contaminants which bioaccumulate in the food chain. Some of these chemicals, 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) and polychlorinated biphenyls (PCBs), have been suggested to be of significance in the aetiology of breast cancer. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an anti-oestrogen in animal studies and should be thus lower the risk of breast cancer. The other isomers of polychlorinated dibenzo-p-dioxins (PCDDs) or the chemically related polychlorinated dibenzofurans (PCDFs) have not been tested regarding carcinogenesis of the breast. The purpose of this study was to investigate whether PCDDs or PCDFs influence the risk for breast cancer. Consecutive patients who underwent surgery for a breast disease between 1993 and 1995 were recruited for the study. Cases were 22 patients with infiltrative breast cancer and controls were 19 patients operated for a benign breast disease during the same time period. Approximately 10 g of breast tissue free from tumour was taken from the specimen and frozen until analysis. Fat was extracted, cleaned and analysed with a high-resolution gas chromatograph coupled to a high-resolution mass spectrometer. Median concentrations of octachlorinated dibenzo-p-dioxin (OCDD) were 598 (170-14,880) and 396 (103-1,847) pg/g lipid in the cases and in the controls, respectively. In a multivariate logistic regression analysis controlling for other risk factors for breast cancer increased odds ratio (OR) was obtained for OCDD: 401-1000 pg/g lipid yielded OR 3.8, 95% confidence interval (CI) 0.4-39, > 1000 pg/g lipid gave OR 5.2, CI 0.4-72. When the lipid OCDD variable was examined as a continuous risk factor there was a 1.09 (9%), CI 0.95-1.25, increase in the adjusted OR for breast cancer per 100 unit (pg/g lipid) increase in OCDD. No differences were found between cases and controls for the other six tested PCDDs. Mean concentration of TCDD was in the cases 3.6 (1.0-7.9) and in the controls 3.3 (1.1-6.3) pg/g lipid. For PCDFs no significant differences were found between cases and controls. The results were not changed if oestrogen or progesterone receptor status, S-phase fraction and DNA ploidy were considered. Breast tissue concentration of OCDD was increased in cancer patients, whereas the concentrations of other PCDDs and PCDFs were equal in cases and controls. 相似文献
93.
G Mangiapan M Vokurka L Schouls J Cadranel D Lecossier J van Embden AJ Hance 《Canadian Metallurgical Quarterly》1996,34(5):1209-1215
The rapid identification of mycobacterial DNA in clinical samples by PCR can be useful in the diagnosis of tuberculous infections, but several large studies have found that the sensitivity of this approach is not better than that of culture. In order to improve the sensitivity of detection of mycobacterial DNA in clinical specimens from patients with paucibacillary forms of tuberculosis, we have developed a procedure permitting the specific capture of mycobacterial DNA in crude samples prior to amplification, thereby concentrating the target sequences and removing irrelevant DNA and other potential inhibitors of the amplification reaction (sequence capture-PCR). By using this approach to capture and amplify two different sequences specific for organisms of the Mycobacterium tuberculosis complex (IS6110 and the direct repeat region), it was possible to detect as little as one genome of mycobacterial DNA in samples containing up to 750 micrograms of total DNA, representing a 10- to 100-fold increase in sensitivity compared with that obtained by purifying total DNA prior to amplification. Detection of the IS6110 sequence in pleural fluid samples from patients with tuberculous pleurisy by sequence capture-PCR gave positive results in 13 of 17 cases, including 3 of 3 culture-positive samples and 10 of 14 culture-negative samples. In contrast, when total DNA was purified from these samples by adsorption to a silica matrix prior to amplification, only the three culture-positive samples were positive by PCR. The sensitivity of detection of the direct repeat sequence in these samples by sequence capture-PCR was similar to that of IS6110 and, in addition, permitted immediate typing of the strains from some patients. We conclude that sequence capture-PCR improves the sensitivity of detection of mycobacterial DNA in paucibacillary samples. This approach should be useful in detecting rare target sequences from organisms implicated in other pathologic processes. 相似文献
94.
Techniques which are currently used to measure skeletal muscle blood flow (SMBF) in patients with congestive heart failure (CHF) are neither convenient nor accurate. They have led to discrepant results in patients with congestive heart failure and are, in part, responsible for the ongoing debate regarding the factors which limit the rise in body oxygen consumption during exercise in these patients. However, direct measurement of SMBF may not be needed during exercise in patients with severe CHF. Their skeletal muscles maximally extract oxygen. Consequently, increase in oxygen consumption by the skeletal muscles is only mediated by a concomitant increase in SMBF. In patients with severe CHF, peak body oxygen consumption attained during maximal exercise closely depends on the rise in SMBF, and thus provides an indirect measurement of SMBF. 相似文献
95.
Muralidhar N. Ingale Vijaykumar V. Mahajani 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,64(1):80-86
The effectiveness of the hybrid system sonication followed by wet oxidation (SONIWO) to treat otherwise refractory waste has been demonstrated. In such a hybrid system homogeneous CuSO4 catalyst was found to be very efficient. 相似文献
96.
V. A. Arzamastsev N. L. Sardaev A. S. Kochergin 《Metal Science and Heat Treatment》1996,38(11):477-479
The technological process of cold forging applied for the first time in the production of the casing of the internal joint with races is described. The process operations of cold forging and the annealing and carburizing regimes for this part me described. 相似文献
97.
G Chessa Ricotti R Cutrì A De Bernardi M Funis S Frediani 《Canadian Metallurgical Quarterly》1995,17(3):271-273
The authors describe 5 cases, 3 boys and 2 girls, with idiopathic growth hormone deficiency in prepubertal age, treated with human growth hormone. In four of five cases the response to treatment with GH was relevant. Only in one case (F1) the response was negative. The results of this study confirm that rhGH is a safe and effective therapy in children with GHD. 相似文献
98.
O. V. Denisenko 《Measurement Techniques》1996,39(11):1092-1094
A method is considered for increasing the immunity from interference of broadband systems for measuring and transmitting information.
It is based on utilizing nonlinear methods to process spread-spectrum signals. The possibility is investigated of using a
quasioptimal receiving device which can be implemented in practice. It is shown that the proposed method makes it possible
to solve the rejection problem at the physical level.
Translated from Izmeritel'naya Tekhnika, No. 11, pp. 13–15, November, 1996. 相似文献
99.
Summary The synthesis of new high optical abrasion resistance coating materials has been undertaken by functionalizing melamine and
tris(m-aminophenyl)phosphine oxide with a triethoxysilane containing reagent. These highly functionalized compounds have been
used for coating a bis-phenol-A polycarbonate substrate by the sol-gel method. Preliminary data shows the abrasion resistance
of the polymer substrate is considerably improved when it is coated by these optically clear materials. 相似文献
100.
Many current implementations of protocols such as the Transmission Control Protocol/Internet Protocol (TCP/IP) are inefficient because data are often accessed more frequently than necessary. Three techniques that reduce the need for memory bandwidth are proposed. The techniques are copy-on-write, page remapping, and single-copy. Afterburner, a network-independent card that provides the services that are necessary for a single-copy protocol stack, is described. The card has 1 MByte of local buffers and provides a simple interface to a variety of network link adapters, including HIPPI and asynchronous transfer mode (ATM). Afterburner can support transfers to and from the link adapter card at rates up to 1 Gbit/s. An implementation of TCP/IP that uses the features provided by Afterburner to reduce the movement of data to a single copy is discussed. Measurements of the end-to-end performance of Afterburner and the single-copy implementation of TCP/IP are presented 相似文献