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排序方式: 共有2217条查询结果,搜索用时 15 毫秒
821.
TB Kinney SC Rose KE Weingarten K Valji SB Oglevie AC Roberts 《Canadian Metallurgical Quarterly》1997,8(6):1029-1037
PURPOSE: A comparison of tilting, caval coverage, asymmetry, and insertion problems with the over-the-wire stainless-steel and titanium versions of the Greenfield filter. MATERIALS AND METHODS: The study compared 104 stainless-steel and 141 titanium Greenfield inferior vena cava (IVC) filter insertions. The angle the sheath and deployed filter made relative to the cava, as well as filter strut distribution, were determined from spot films. The proportionate caval coverage was computed from the cavogram (anteroposterior projection). Mean filter tilts, subgrouped by insertion site, and caval coverage were compared with the Student t test, whereas strut patterns were analyzed with a contingency table. RESULTS: The filter caval and sheath caval angles correlated. The filter caval angles varied with insertion site, but were lowest with a right jugular approach. Caval coverage was identical with both designs. The stainless-steel version resulted in a more uniform distribution of struts in comparison with the titanium version. The incidence of insertion problems was not significantly different between the filter types. CONCLUSIONS: While IVC filter tilting was not improved with the newer design, the pattern of struts was more uniformly symmetric with the stainless-steel device. The right jugular insertion site was associated with the lowest filter caval angles and the most symmetric pattern of struts. 相似文献
822.
INTRODUCTION: Chondromas are rare intracranial tumors. The authors present two cases of intracranial intradural chondroma, one originating from the falx cerebri and the other from the dura mater of the convexity. METHOD AND RESULTS: Diagnostic procedures, including magnetic resonance imaging, and surgical findings are described. In both cases, pre-operative diagnosis could have been at least suspected, and the tumor was completely removed, without recurrence after a follow-up of many years. The pathogenesis and pathological findings are discussed, and cases from the literature are reviewed. CONCLUSION: Benign intradural chondroma has a good prognosis, with no recurrence after surgical excision in most cases. 相似文献
823.
824.
E Chamoux V Coxam P Lebecque MJ Davicco SC Miller JP Barlet 《Canadian Metallurgical Quarterly》1997,61(2):79-91
The effects of 17 beta-estradiol (E), dihydrotestosterone (D, a non aromatisable androgen), and progesterone (P) on osteogenesis were studied on fetal rat cartilaginous anlagues cultivated in vitro. The three medial metatarsal rudiments were harvested at day 19 of gestation and grown in 1% BSA MEM medium (MO 643, Sigma) without serum nor antibiotics. After a 18h preincubation period, hormones were added for 8 days. Paired controls were incubated in the same volume of medium. The length, the metacarpal thickness and the size of the mineralized zone were measured every day, using a calibrated eyepiece (magnification X 40). DNA and protein synthesis, cartilage metabolism and mineralization were evaluated by monitoring the incorporation of 3H-Thymidine, 3H-Proline, 35S and 45Ca into anlagues for the last three hours of incubation, respectively. The dose/response effect of each steroid was studied at the concentrations of 10(-4) M, 10(-6) M, 10(-7) M and 10(-9) M. No difference was observed between male and female fetuses. A significant positive effect on total length (% of length measured at harvesting day) was observed with the 10(-7) M dose of E (163% +/- 2 vs 148% +/- 4 in controls) or D (158% +/- 3). Endochondral growth was not modified by P treatment. The effect of the three steroids (given at a dose of 10(-7) M) alone or as combinations (E, D, P, EP, ED, PD, EPD) confirmed the positive effect of E on endochondral growth and, to a lesser extend, of D and the association ED. Nevertheless, D had a better effect than E on endomembranous growth. On the contrary, P did not affect growth neither administrated alone nor in combination with E or D, while a positive effect of P on mineralization was demonstrated. The treatment associating the three steroids slowed down all the parameters concerning growth but strongly stimulated calcification. 相似文献
825.
Hydroxylation of dehydroabietic acid by Fusarium species 总被引:2,自引:0,他引:2
AA Tapia MD Vallejo SC Gouiric GE Feresin PC Rossomando DA Bustos 《Canadian Metallurgical Quarterly》1997,46(1):131-133
A novel compound, 1 beta-hydroxydehydroabietic acid has been obtained by the microbial transformation of dehydroabietic acid, using cultures of Fusarium oxysporum and F. moniliforme. Its antibacterial activity was also tested. 相似文献
826.
LR Goldfarb NP Alazraki D Eshima LA Eshima SC Herda RK Halkar 《Canadian Metallurgical Quarterly》1998,208(2):505-509
PURPOSE: To evaluate the use of 0.22-micron filtration of technetium-99m sulfur colloid particles in the optimization of lymphoscintigraphy. MATERIALS AND METHODS: Forty-one consecutive lymphoscintigraphic studies obtained with 0.22-micron filtration of Tc-99m sulfur colloid in 41 patients (26 men, 15 women; average age, 55.4 years) and 41 consecutive studies obtained with 5.0-micron filtration in 41 patients (20 men, 21 women; average age, 54.5 years) were retrospectively, randomly reviewed. Studies were evaluated for lymphatic channel depiction and sentinel lymph node depiction. Studies included immediate flow images (obtained at 10 seconds per frame) and multiview static images obtained up to 2 hours after intradermal Tc-99m sulfur colloid injection. RESULTS: The number of drainage beds visualized was 52 with 5.0-micron filtration and 51 with 0.22-micron filtration (P = .570). The number of lymphatic channels visualized was 45 with 5.0-micron filtration and 75 with 0.22-micron filtration (P = .006). The number of lymph nodes visualized was 102 with 5.0-micron filtration and 123 with 0.22-micron filtration (P = .123). The number of studies judged as optimal (i.e., depicted lymphatic channels leading to sentinel nodes) was 10 with 5.0-micron filtration and 19 with 0.22-micron filtration (P = .038). The number of studies with depicted lymph nodes but no depicted lymphatic channel was 15 with 5.0-micron filtration and six with 0.22-micron filtration (P = .023). CONCLUSION: The use of 0.22-micron filtration in the preparation of Tc-99m sulfur colloid substantially improves study quality and increases the diagnostic certainty in the identification of sentinel lymph nodes. 相似文献
827.
828.
G Moreno A Merino A Mercado JP Herrera J González-Salazar R Correa-Rotter SC Hebert G Gamba 《Canadian Metallurgical Quarterly》1998,31(4):1002-1006
The antiproteinuric effect of angiotensin converting enzyme (ACE) inhibition in insulin-dependent diabetes mellitus (IDDM) patients with diabetic nephropathy varies considerably. Therefore, we tested the potential role of an insertion (I)/deletion (D) polymorphism of the ACE gene on this early antiproteinuric responsiveness in an observational follow-up study. Sixty (II, N = 13; ID, N = 26 and DD, N = 21) young hypertensive IDDM patients suffering from diabetic nephropathy were investigated during three months before and for the initial six month period during ACE inhibition [captopril 44 (SD 22) mg/24 hr, no differences in drug dose between groups]. Blood pressure (MABP) and albuminuria (ELISA) were measured three (1 to 6) times before and three (1 to 13) times during ACE inhibition. At baseline the groups (II/ID/DD) had comparable (1) mean arterial blood pressure (MABP mm Hg) of 113 +/- 10/108 +/- 9/114 +/- 8, (2) albuminuria (geometric mean with 95% CI) 1394 (747 to 2608)/1176 (844 to 1797) and 1261 (827 to 2017) mg/24 hr, and (3) serum creatinine (geometric mean with 95% CI), 80 (68 to 93)/85 (76 to 97)/103 (85 to 119) mumol/liter, respectively. Angiotensin converting enzyme inhibition induced a significant reduction in MABP, albuminuria and kidney function in all three groups (II/ID/DD; P < 0.05): (1) MABP (mean +/- SD) 12 +/- 7/5 +/- 7/8 +/- 9 mm Hg (ANOVA, P = 0.02); (2) albuminuria [mean (95% CI)] 61 (34 to 77)/22 (3 to 37)/31 (13 to 46) %, (ANOVA, P < 0.01); and (3) increasing serum creatinine [mean (95% CI)] 8 (4 to 12)/9 (3 to 16)/8 (0 to 16) % (ANOVA, NS), respectively. Adjusting for differences in reduction in MABP did not change the association between decrease in albuminuria and ACE/ID genotypes (P < 0.01). A multiple linear regression analysis revealed that the ACE/ID polymorphism, albuminuria and MABP at baseline independently influenced the decline in albuminuria after initiation of ACE inhibition (R2 = 0.21, P < 0.01). A significant association between changes in MABP and albuminuria was demonstrated (R2 = 0.16, P < 0.01). Our data show that hypertensive albuminuric IDDM patients with the II genotype are particularly susceptible to commonly advocated renoprotective treatment. 相似文献
829.
SC Chang 《Canadian Metallurgical Quarterly》1998,52(2):229-239
Nucleoside triphosphate hydrolase is an abundant protein secreted by the obligate protozoan parasite Toxoplasma gondii. The protein has apyrase activity, degrading ATP to the di- and mono-phosphate forms. Because T. gondii is incapable of de novo synthesis of purines, it is postulated that NTPase may be used by the parasite to salvage purines from the host cell for survival and replication. To elucidate the molecular mechanisms of NTP gene expression, we isolated from the virulent RH strain of T. gondii the putative promoter region of three tandemly repeated NTP genes (NTP1, 2, 3). Using deletion constructs linked to the chloramphenicol acetyl transferase (CAT) reporter gene, we defined an active promoter within the first 220 bp. Sequence analysis of this region reveals the lack of a TATA box, but the promoter region is associated with a sequence which resembles an initiator element (Inr) in the NTP1 and NTP3 genes. This sequence which is similar to other Inrs known to regulate the expression of a wide variety of RNA polymerase II genes, is required for NTP expression. The NTP3 promoter contains sufficient information for developmentally regulated expression of CAT activity when the actively replicating stage tachyzoite differentiates into the dormant bradyzoite form. 相似文献
830.
A possible approach to improve the blood compatibility of poly(ether urethane)s (PU) involves the covalent attachment of key molecules on its surface. The purpose of the present study was to design and synthesise a novel non‐thrombogenic biomaterial by modifying the surface of the PU with a zwitterionic monomer of sulfobetaine via a Jeffamine spacer. In this study, sulfobetaine was grafted onto a PU surface through the following reaction steps: (1) The PU surface was activated with hexamethylene diisocyanate (HDI) in toluene at 50 °C in the presence of di‐n‐butyltin dilaurate (DBTDL) as a catalyst. The extent of the reaction was measured by ATR‐FTIR spectra; a maximum number of free NCO groups was obtained after a reaction time of 90 min. (2) One cap of Jeffamine was reacted with isocyanate groups bound on the surface, so Jeffamine was introduced. (3) The PU surface terminated by Jeffamine was recoupled with isocyanate groups by HDI. (4) The hydroxyl groups of 4‐dimethylamino‐1‐butanol (DMAB) or 2‐dimethylaminoethanol (DMAE) were allowed to react with the isocyanate groups capped on Jeffamine. (5) Sulfobetaines were constructed on the surface through the ring‐opening reaction between tertiary amine and 1,3‐propanesultone (PS). It was confirmed by ATR‐FTIR and XPS that the grafted surfaces were composed of sulfobetaine. The results of the contact‐angle measurements and water absorption showed that they were strongly hydrophilic. The results of this platelet adhesion experiment as a preliminary test showed that PU grafted with sulfobetaine has good blood compatibility featured by the low platelet adhesion. Copyright © 2004 Society of Chemical Industry 相似文献