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931.
932.
HE Jones CL Eaton D Barrow CM Dutkowski JM Gee K Griffiths 《Canadian Metallurgical Quarterly》1997,30(4):219-231
Murine acute myeloid leukemia is characterized by chromosome 2 aberrations, and genesis of the marker chromosome 2 by radiation is suspected to be an initiating event of radiation leukemogenesis. A detailed analysis of the type and frequency of chromosome 2 aberrations in murine bone marrow cells at an early stage after irradiation is provided here. A total of 40 male C3H/He mice was exposed to 137Cs gamma-ray at a dose of 1, 2 or 3 Gy, and sacrificed 24 hours after irradiation. Metaphase samples prepared from bone marrow cells were Q-banded for karyotyping or painted with DNA probes specific to chromosome 2. In 5 mice analyzed by karyotyping, one mouse showed high frequency of the marker aberrations as well as other chromosome 2 aberrations. Chromosome painting analysis for the rest of the mice also detected 3 animals showing significantly high frequencies of chromosome 2 aberrations. Dose-dependence of the frequencies was observed even among those mice that tended to be sensitive. The results indicated that there was a subgroup of mice carrying hypersensitive chromosome 2. The subgroup could be leukemia-sensitive if radiation-induced chromosome aberrations are responsible for an early change in myeloid leukemogenesis. 相似文献
933.
Locally advanced primary colorectal cancer: intraoperative electron and external beam irradiation +/- 5-FU 总被引:1,自引:0,他引:1
LL Gunderson H Nelson JA Martenson S Cha M Haddock R Devine JM Fieck B Wolff R Dozois MJ O'Connell 《Canadian Metallurgical Quarterly》1997,37(3):601-614
PURPOSE: For locally advanced primary colorectal cancer, our institution has combined intraoperative electron irradiation (IOERT) with external beam irradiation (EBRT) +/- 5-fluorouracil (5-FU) and surgical resection. Disease control and survival were compared with the current IOERT and prior non-IOERT regimens. METHODS AND MATERIALS: From April 1981 through August 1995, 61 patients received an IOERT dose of 10-20 Gy, usually combined with 45-55 Gy of fractionated EBRT; 56 had minimum follow-up of 18 months. The amount of residual disease remaining at IOERT after exploration and maximal resection in the 56 patients was gross in 16, < or = microscopic in 39, and unresected in 1. RESULTS: Survival (SR) and disease control were analyzed as a function of potential prognostic factors. Factors that achieved statistical significance for improved overall survival included treatment sequence of preop EBRT + 5-FU (vs. postoperative EBRT + 5-FU, p = 0.003) and < or = microscopic residual disease after maximal resection (vs. gross residual, p = 0.005). Those that appeared to favorably impact disease-free survival included EBRT + 5-FU (vs. EBRT alone, p = 0.01), < or = microscopic residual (vs. gross, p = 0.0014), and colon site of primary (vs. rectum, p = 0.009). Failures within an irradiation field have occurred in 4 of 16 patients (25%) who presented with gross residual after partial resection vs. 2 of 39 (5%) with < or = microscopic residual after gross total resection (p = 0.01). The significant prognostic factors for a decrease in distant metastases were the same as for disease-free SR with respective p-values of 0.013 (EBRT + 5-FU), 0.008 (microscopic residual), and 0.03 (colon primary). The current data suggests a relationship between IOERT dose and incidence of Grade 2 or 3 neuropathy (< or = 12.5 Gy--1 of 29 or 3%, > or = 15 Gy--6 of 26 or 23%, p = 0.03). CONCLUSIONS: Both overall survival and disease control appear to be improved with the addition of IOERT to standard treatment. More routine use of systemic therapy is indicated as a component of IOERT containing treatment regimens because the incidence of distant metastases was 50% of patients at risk. 相似文献
934.
935.
E Sloth M Kruse KC Houlind EM Pedersen JM Hasenkam 《Canadian Metallurgical Quarterly》1997,36(3):377-385
OBJECTIVE: To give a detailed evaluation on main pulmonary artery blood velocity patterns, in patients with ischemic heart disease and to provide recommendations for pulsed Doppler sample volume placement, in order to optimize cardiac output estimation. METHODS: Using magnetic resonance phase and esophageal color Doppler velocity mapping in 12 patients with ischemic heart disease and undergoing coronary artery by-pass grafting, very similar data on pulmonary artery blood velocity patterns were provided for comparison with each other. RESULTS: Peak blood velocities were located in the inferior half of the main pulmonary artery cross-sectional area. Early after peak systole the highest velocities shifted towards the superior/left (major curvature) with a simultaneous decrease in velocities inferiorly. The velocity decrease further evolved into retrograde flow to the inferior/right (minor curvature). This feature was significantly enhanced compared to earlier findings in healthy volunteers. The mean temporal blood velocity profiles were asymmetrically skewed, thereby giving unreliable cardiac output estimates based on single point Doppler blood velocity recordings. The error incurred may amount to more than 100% in extreme cases. According to our data, optimal assessment of cardiac output should be based on multiple sample volumes placed along the inferior/right to superior/left diameter. CONCLUSIONS: MR-phase velocity mapping and multiplane transesophageal color Doppler recordings provided similar blood velocity patterns in patients with ischemic heart disease. The skewness of the mean temporal blood velocity profile is enhanced compared with healthy subjects, resulting in error in the assessment of CO by means of pulsed Doppler echocardiography. By using multiple Doppler sample volumes, the error can be minimized. 相似文献
936.
Porous poly(glycidyl methacrylate-co-ethylene dimethacrylate) monoliths with different porous properties grafted with poly(2-acrylamido-2-methyl-1-propanesulfonic acid) chains using cerium(IV) initiated free-radical polymerization have been prepared and used for the separation of proteins in ion-exchange HPLC mode. Because of the presence of the large pores that are typical of monolithic separation media which allow easy flow of all of the mobile phase, the efficiency of the columns does not deteriorate even at high flow velocities as a result of the specific morphology of the monoliths. Optimization of the chromatographic conditions such as the shape of the mobile phase gradient and the flow rate allows for very fast separation of three proteins in less than 1.5 min. 相似文献
937.
P Kastner N Messaddeq M Mark O Wendling JM Grondona S Ward N Ghyselinck P Chambon 《Canadian Metallurgical Quarterly》1997,124(23):4749-4758
Knock-out of the mouse RXRalpha gene was previously shown to result in a hypoplastic heart ventricular wall, histologically detectable in 12.5 dpc fetuses. We show here that a precocious differentiation can be detected as early as 8.5 dpc in ventricular cardiomyocytes of RXRalpha(-/-) mutants. This precocious differentiation, which is characterized by the presence of striated myofibrils, sarcoplasmic reticulum and intercalated disks, is found after 9.5 dpc in about 50% of RXRalpha(-/-) subepicardial myocytes. In contrast, wild-type subepicardial myocytes remain morphologically undifferentiated up to at least 16.5 dpc. A similar precocious differentiation was observed in 9.5 dpc subepicardial myocytes of several RXRbeta(-/-) and RARalpha(-/-) mutants, as well as in vitamin A-deficient embryos. The proportion of differentiated subepicardial myocytes almost reached 100% in RXRalpha/RXRbeta double null mutants, indicating a partial functional redundancy between RXRalpha and RXRbeta. This differentiation defect was always paralleled by a decrease in the mitotic index. In addition, subepicardial myocytes of RXRalpha(-/-), RXRalpha(-/-)/RXRbeta(-/-) or vitamin A deficient, but not of RXRbeta(-/-) and RARalpha(-/-) embryos, were often flattened and more loosely connected to one another than those of WT embryos. Thus, retinoids are required at early stages of cardiac development to prevent differentiation, support cell proliferation and control the shape of ventricular myocytes, and both RXRs and RARs participate in the mediation of these functions. 相似文献
938.
BT Holt NL Parks GA Engh JM Lawrence 《Canadian Metallurgical Quarterly》1997,20(12):1121-4; discussion 1124-5
One hundred thirty-six primary total knee arthroplasty patients were randomized for the use of closed-suction, nonreinfusable wound drains. Blood loss was identical in the drained and undrained groups. Forty percent of undrained wounds compared with 0% of drained wounds required dressing reinforcement. Sixty-nine percent of undrained wounds compared with 39% of drained wounds developed ecchymosis, measuring 92 cm2 in the undrained group and 28 cm2 in the drained group. This study concludes that a simple wound drain effectively minimizes the undesirable accumulation of blood in the surrounding soft tissues and the postoperative wound dressing after total knee arthroplasty. 相似文献
939.
AL Gutiérrez-Escolano F Medina VR Racaniello RM Del Angel 《Canadian Metallurgical Quarterly》1997,227(2):505-508
Specific polyclonal antibody was raised against D-aspartate (D-Asp) which had been conjugated to glutaraldehyde and was purified by affinity chromatography. Immunohistochemical staining of rat pineal gland with the antibody demonstrated the presence of D-Asp in the cytoplasm of pinealocytes, the predominant cell type in this gland. D-Asp immunoreactivity was more evident in the distal region than in the proximal region of the gland. Pinealocytes in the distal region are presumably involved in the synthesis and secretion of the pineal hormone, melatonin, and the results of staining may indicate some yet unknown role of D-Asp in the regulation of melatonin secretion. 相似文献
940.
E Scherzinger G Ziegelin M Bárcena JM Carazo R Lurz E Lanka 《Canadian Metallurgical Quarterly》1997,272(48):30228-30236
The RepA protein of the mobilizable broad host range plasmid RSF1010 has a key function in its replication. RepA is one of the smallest known helicases. The protein forms a homohexamer of 29,896-Da subunits. A variety of methods were used to analyze the quaternary structure of RepA. Gel filtration and cross-linking experiments demonstrated the hexameric structure, which was confirmed by electron microscopy and image reconstruction. These results agree with recent data obtained from RepA crystals diffracting at 3.5-A resolution (R?leke, D., Hoier, H., Bartsch, C., Umbach, P., Scherzinger, E., Lurz, R., and Saenger, W. (1997) Acta Crystallogr. Sec. D 53, 213-216). The RepA helicase has 5' --> 3' polarity. As do most true replicative helicases, RepA prefers a tailed substrate with an unpaired 3'-tail mimicking a replication fork. Optimal unwinding activity was achieved at the remarkably low pH of 5.5. In the presence of Mg2+ (Mn2+) ions, the RepA activity is fueled by ATP, dATP, GTP, and dGTP and less efficiently by CTP and dCTP. UTP and dTTP are poor effectors. Nonhydrolyzable ATP analogues, ADP, and pyrophosphate inhibit the helicase activity, whereas inorganic phosphate does not. The presence of Escherichia coli single-stranded DNA-binding protein stimulates unwinding at physiological pH 2-3-fold, whereas the RSF1010 replicon-specific primase, RepB' protein, has no effect, either in the presence or in the absence of single-stranded DNA-binding protein. 相似文献