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991.
SM Allen-Gil CP Gubala R Wilson DH Landers TL Wade JL Sericano LR Curtis 《Canadian Metallurgical Quarterly》1997,33(4):378-387
Organochlorine (OC) concentrations in surface sediment, snails (Lymnea sp.), and two freshwater fish species (grayling, Thymallus arcticus; and lake trout, Salvelinus namaycush) from four lakes in the US Arctic were determined. In surface sediment, chlorinated benzenes (including hexachlorobenzene, HCB), and p,p'-DDT were the primary analytes detected (max = 0.7 ng/g dry wt), while individual polychlorinated biphenyl (PCB) congeners were always below 0.1 ng/g. A wider range of compounds and higher concentrations were found in lake trout, the top predatory fish species in the same lakes. The concentration ranges for hexachlorocyclohexanes (HCHs), chlordane-related compounds (CHLORs), DDTs, and PCBs in lake trout and grayling were similar to those reported for other arctic freshwater fish (1-100 ng/g wet wt), but one to two orders of magnitude lower than Great Lakes salmonids. Nitrogen isotope analysis confirmed that differences in OC concentrations between grayling and lake trout are explained partly by differences in food web position. 相似文献
992.
993.
JR Rider G Moore JM Payrat D Chan C Morse GR Standen DH Pamphilon 《Canadian Metallurgical Quarterly》1996,94(1):184-190
We utilized indirect immunocytochemistry to demonstrate the presence of growth factors and their receptors in human pre-embryos and Fallopian tubes. In pre-embryos, only transforming growth factor-alpha (TGF-alpha) and the intracellular domain of epidermal growth factor receptor (EGFR) were found at the 4-cell stage. In 8- to 14-cell pre-embryos, TGF-alpha, the intracellular and extracellular domains of EGFR, and insulin-like growth factor-I and its receptor were found. Antibodies against TGF-alpha stained all Fallopian tube specimens, while the extracellular domains of EGFR was only found in specimens from patients with either blood type A or AB. These results suggest a cross-reactivity between the extracellular domain of the EGFR and blood group antigens. Our novel demonstration of growth factor receptor staining in human pre-embryos shows that growth factor receptor localization is dependent on the developmental stage of human pre-embryos. We have also established a potentially important link between the Fallopian tube which secretes growth factors and the localization of growth factor receptors in pre-embryos. These findings are compatible with the hypothesis that tubal secretions are embryotrophic for the early development of the pre-embryo. 相似文献
994.
M Chvapil DP Speer H Holubec TA Chvapil DH King 《Canadian Metallurgical Quarterly》1993,27(3):313-325
ACL substitutes made of braided or plied purified collagen fibers and cross-linked with hexamethylenediisocyanate were implanted into a total of 14 adult goats to achieve resorption within 8 to 10 months. Two types of collagen fiber prostheses differing in degree of collagen purification were tested. The implants were harvested 2 to 11 months postimplantation, tested for mechanical strength, and evaluated by morphological methods. In the first group (n = 5), the less purified and less cross-linked collagen fiber ACL implant induced fast connective tissue ingrowth. At 6 months postimplantation, 40 to 60% of the collagen implant was resorbed. No studies on breaking strength were done in this group. In the second group, highly purified and more crosslinked ACL implants were less infiltrated by cells and were resorbed only by 10 to 20%. Still, the breaking strength was decreased to 10% of the original implant strength. In the second group, the fixation of the ACL implant in the bone tunnel with a bone wedge was insufficient (n = 6); however, additional fixation with metal screws was successful (n = 3). We conclude that cross-linked collagen fibers alone cannot be used as a safe ACL substitute as they quickly lose mechanical strength despite limited biodegradation. 相似文献
995.
Viruses which cause persistence in the naturally infected host are predicted to have evolved immune evasion mechanisms. Human cytomegalovirus (HCMV) causes significant morbidity and mortality in immunocompromised patients yet persists without clinical manifestations in seropositive individuals who have normal immune function. We report that HCMV infection in vitro impairs major histocompatibility complex class I (MHC-I) assembly accompanied by resistance to killing by cytotoxic CD8+ T lymphocytes. Pulse-chase metabolic labelling experiments show that MHC-I complexes continue to be assembled by both uninfected and HCMV-infected cells. However, MHC-I molecules are unstable in HCMV-infected cells and are rapidly broken down. Endoglycosidase H treatment of immunoprecipitates indicates that the breakdown of MHC-I complexes in HCMV-infected cells occurs primarily in a pre-Golgi compartment. Interference with normal MHC-I assembly and expression, if relevant in vivo, may have implications for the restriction of the diversity of the CD8+ cytotoxic T lymphocyte repertoire directed against HCMV antigens and may be an important mechanism of viral persistence. 相似文献
996.
Examined the relationship between the psychological testing and information processing approaches in assessing attention. Eighty-seven subjects (57 females, 30 males) undertook eight psychological tests of attention and a visual-spatial reaction-time task. Using the cognitive-correlate method (Posner & McLeod, 1982), it was found that three components of attention (viz., visual-motor scanning, sustained selective processing, and visual/auditory spanning) derived from the psychological tests could be significantly predicted by specific, yet different, combinations of six indices of information processing (mean reaction time (RT), mean movement time (MT), feature extraction, identification, response selection, and motor adjustment): (a) mean RT and mean MT were found to be the most important indices for predicting performance on visual-motor scanning; (b) the motor-adjustment stage was found to be the most important index for predicting performance on sustained selective processing; (c) the response-selection stage was found to be the most important index for predicting performance on visual/auditory spanning. These relationships are important for supporting the construct-related validity of the psychological tests of attention and for extending the generality and applicability of the RT task. 相似文献
997.
Cytogenetic data about 145 chorionic villus samples obtained between the 13th and 35th week of gestation are reported. 'Late' chorionic villus sampling (CVS) was used to resolve different situations: failed amniotic fluid cell cultures (5 cases); confirmation of an abnormal karyotype, previously diagnosed as mosaic (14 cases); and ultrasound fetal malformation (23 cases). Most of the samples (103 cases) were analysed for the classical indications and in these cases, the principal aim was to obtain a rapid fetal karyotype. Excluding the cases used to check fetal karyotype, a chromosomal aberration was found in 11 out of 131 biopsies. In four cases of the group in which the fetal karyotype was checked (14 cases), the pathology observed at the first diagnosis was confirmed, while in the remaining ten cases the anomaly was not observed. 相似文献
998.
999.
BACKGROUND: The association of neoplastic disease and thromboembolic disorders was first recognized by Trousseau in 1865. Abnormalities of blood coagulation tests have been reported in the majority of patients with cancer, including ovarian carcinoma. However, Trousseau's syndrome has rarely been reported in women with ovarian carcinoma. METHODS: A literature search for cases of Trousseau's syndrome in association with ovarian carcinoma was performed using the MEDLINE database. Case notes of patients with ovarian carcinoma treated at St. George's Hospital were reviewed and cases of Trousseau's syndrome identified. RESULTS: We report a series of 4 cases of Trousseau's syndrome in association with ovarian carcinoma occurring over a 3- to 4-year period, and highlight the particular difficulties associated with the management of these thromboembolic effects. CONCLUSIONS: Trousseau's syndrome can impair quality of life in patients with advanced ovarian carcinoma and enhanced anticoagulation regimens may be required for effective palliation. 相似文献
1000.
SL Turner H Hamilton M Jacobs LM Angood DH Dwyer 《Canadian Metallurgical Quarterly》1997,32(127):603-614
This study examined the impact of exposure to fashion magazines on women's body image satisfaction. Participants were 39 undergraduate women, randomly assigned to two experimental conditions: half viewed fashion magazines prior to completing a body image satisfaction survey, and the remaining half, news magazines. Mean height and weight did not differ for the two groups. As hypothesized, women who viewed fashion magazines preferred to weigh less, were less satisfied with their bodies, were more frustrated about their weight, were more preoccupied with the desire to be thin, and were more afraid of getting fat than were their peers who viewed news magazines. 相似文献