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排序方式: 共有1095条查询结果,搜索用时 15 毫秒
951.
JA Coffman R Rai DM Loprete T Cunningham V Svetlov TG Cooper 《Canadian Metallurgical Quarterly》1997,179(11):3416-3429
Nitrogen catabolic gene expression in Saccharomyces cerevisiae has been reported to be regulated by three GATA family proteins, the positive regulators Gln3p and Gat1p/Nil1p and the negative regulator Dal80p/Uga43p. We show here that a fourth member of the yeast GATA family, the Dal80p homolog Deh1p, also negatively regulates expression of some, but not all, nitrogen catabolic genes, i.e., GAP1, DAL80, and UGA4 expression increases in a deh1 delta mutant. Consistent with Deh1p regulation of these genes is the observation that Deh1p forms specific DNA-protein complexes with GATAA-containing UGA4 and GAP1 promoter fragments in electrophoretic mobility shift assays. Deh1p function is demonstrable, however, only when a repressive nitrogen source such as glutamine is present; deh1 delta mutants exhibit no detectable phenotype with a poor nitrogen source such as proline. Our experiments also demonstrate that GATA factor gene expression is highly regulated by the GATA factors themselves in an interdependent manner. DAL80 expression is Gln3p and Gat1p dependent and Dal80p regulated. Moreover, Gln3p and Dal80p bind to DAL80 promoter fragments. In turn, GAT1 expression is Gln3p dependent and Dal80p regulated but is not autogenously regulated like DAL80. DEH1 expression is largely Gln3p independent, modestly Gat1p dependent, and most highly regulated by Dal80p. Paradoxically, the high-level DEH1 expression observed in a dal80::hisG disruption mutant is highly sensitive to nitrogen catabolite repression. 相似文献
952.
Is chromosome 9 loss a marker of disease recurrence in transitional cell carcinoma of the urinary bladder? 总被引:1,自引:0,他引:1
JM Bartlett AD Watters SA Ballantyne JJ Going KM Grigor TG Cooke 《Canadian Metallurgical Quarterly》1998,77(12):2193-2198
Investigation of transitional cell carcinoma of the urinary bladder (TCC) patients classified by recurrence and/or progression has demonstrated that loss of chromosome 9, as detected by FISH analysis of the pericentromeric classical satellite marker at 9q12, occurs early. A total of 105 TCCs from 53 patients were analysed in situ by two independent observers for loss of chromosome 9 using quantitative fluorescence in situ hybridization (FISH). All 53 primary tumours were evaluated for chromosomes 9, 7 and 17. Normal ranges for chromosomal copy number were defined for normal skin epidermis and bladder epithelium. Values for chromosome 9 copy number outwith the range 1.51-2.10 (mean +/- 3 x s.d. of normal values) were significantly abnormal. Twenty-five TCCs were detected with consistent monosomic scores. Of 89 TCCs, in which multiple tumour areas were analysed, 85 tumours (96%) demonstrated the same chromosome 9 copy number in all areas (2-6) analysed; only three tumours demonstrated heterogeneity for this locus. A total of 36% (12 out of 33) of patients with subsequent disease recurrence demonstrated loss of chromosome 9 in their primary and all subsequent TCCs analysed. Only a single patient (n = 20) with non-recurrent TCC showed loss of chromosome 9 (P = 0.0085). Of 53 primary tumours, eight showed significant elevation of chromosome 17. Of these patients, six demonstrated elevation in chromosome 7 copy number. No abnormalities were observed in non-recurrent patients. This study describes rapid quantitation of chromosomal copy number by FISH using a pericentromeric probe for chromosome 9 in TCC of the urinary bladder. Routinely fixed and processed material was evaluated without disaggregation. Strict quality control of FISH demonstrated that this technique was reproducible in a clinical environment and could be used to detect genetic changes relevant to patient outcome. It is proposed that loss of chromosome 9 from primary TCC of the urinary bladder identified patients at high risk of recurrence and possible progression. 相似文献
953.
VV Poliakov SM Ivanova VB Noskov OI Labetskaia IuV Iarlykova VV Karashtin VI Legen'kov TG Sarycheva ZG Shishkanova GI Kozinets 《Canadian Metallurgical Quarterly》1998,32(2):9-18
In the nearly 15-month mission aboard MIR the cosmonaut-physician and members of three crews (MIR-15, -16, and -17) carried out a program of hematological investigations. Most of the changes related to the red blood system and included reduction in hemoglobin and hematocrit. Erythrocytes had decreased concentration and took on abnormal forms. There were also signs of altered metabolism of erythrocytes. Of interest are phase-by-phase variations in the levels of erythrocytes in the course of long-term stay in microgravity, and absence of a convincing correlation between hemoglobin, erythrocyte and hematocrit levels. But for lymphocytosis that returned to the norm already on the first day of recovery, no material changes occurred to the leukocyte profile. Investigations at the landing site displayed erythropenia, decreased reticulocytes and ensuing reticulocyte reaction, and gradual regain of the erythrocyte number that can be viewed as a normal physiological reaction of the blood system to the set of factors of spaceflight and early readaptation. Besides, the investigations showed a large individually of blood reactions to prolonged stay in space flight. 相似文献
954.
J Hochberg M Ardenghy J Yuen R Gonzalez-Cruz Y Miura RM Conrado TG Pait 《Canadian Metallurgical Quarterly》1998,102(2):385-9; discussion 390-2
Midline wound dehiscence in the back with exposure of spinal stabilization devices remains a challenging problem, mainly in the presence of infection. Usually, the treatment consists of instrumentation removal, wound debridement, and antibiotic therapy. These can result in instability of the spine and significantly prolong the hospitalization. The use of muscle and musculocutaneous flaps provides excellent soft-tissue coverage, obliterates the dead space, controls the infection, and creates conditions to salvage the hardware. Eight cases of spinal rod instrumentation, complicated by wound infection and dehiscence, have been treated successfully with single or multiple muscles and musculocutaneous flaps. Our method of treatment for these complex wounds, in two institutions, is discussed. 相似文献
955.
956.
The effect of neutron irradiation and post-irradiation thermal annealing on tensile and impact properties of Cr–Ni–Mo steel used for WWER-1000 reactor pressure vessel (RPV) manufacturing was studied. A gap in yield stress and ultimate tensile stress fluence dependence at the fluence range of 0–3×1023 neutrons m−2 was observed while ductile-to-brittle transition temperature (DBTT) was continuously increasing with damage dose. The post-irradiation annealing recovery of tensile properties was found to be higher than the one of impact properties. Over-recovery of tensile properties due to 460 and 490°C post-irradiation annealings were observed. The annealing effectiveness of WWER-440 and WWER-1000 grades was compared. Nickel was supposed to affect both the radiation sensitivity and the post-irradiation residual DBTT shift of WWER-1000 type steel. 相似文献
957.
Current collective and individual dose rates to humans are estimated from the consumption of seafood harvested in the Arctic Seas. Statistical data on catches are used for the dose assessment, as well as observed data (1991-1994) on the radioactivity of marine biota. The actual collective dose rates to the world population are estimated to be: 2.7-4.5 manSv/year due to consumption of seafood from the Barents Sea, and 0.03 manSv/year-due to seafood from the Kara Sea. The contribution of 137Cs to the collective dose rate is about 90%. Current individual dose rates to high-rate consumers are estimated to be: 2.6 x 10(-6) Sv/year due to seafood from the Barents Sea; and 4.2 x 10(-6) Sv/year-due to seafood from the Kara Sea. The future radiological impact of the radioactive waste (RW) disposals in the Kara Sea is simulated for the period over 1000 years, using the regional box model of the Arctic Seas. The model predictions are made for three hypothetical scenarios of long-term radionuclide releases, prepared within the framework of the International Arctic Seas Assessment Project. The potential collective dose to world population truncated to 3000 AD is shown to be not higher than 0.13 manSv. The maximum individual dose rates from Arctic seafood consumption are estimated to be about 1.2 x 10(-7) Sv/year. The predicted doses are much smaller than the actual doses due to the current radioactive contamination of the Arctic Seas. 相似文献
958.
A k Zhangabylov S V Nikolaeva L I Kalamkarova L A Il'chenko B Muzapbarov 《Voprosy pitaniia》1986,(2):16-18
The intestinal absorption of vitamin B12 and its blood content have been proved to lower in patients with chronic enterocolitis. Dietetics including kumiss and shubat promotes normalization of vitamin B12 absorption (p less than 0.05), its blood content growth (p less than 0.05), the intestinal microflora becoming normal. 相似文献
959.
B. A. Nikitin T. V. Nikolaeva E. S. Serushkina V. N. Antonova V. M. Budnitskii 《Measurement Techniques》1990,33(1):78-80
Translated from Izmeritel'naya Tekhnika, No. 1, pp. 49–50, January, 1990. 相似文献
960.
V. A. Nikolaeva V. I. Ryzhii B. N. Chetverushkin 《Journal of Engineering Physics and Thermophysics》1986,51(3):1117-1124
The algorithms of numerical solution of the system of quasihydrodynamic equations, simulating a dense electron-hole plasma in binary heterostructures, are considered and treated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 51, No. 3, pp, 492–501, September, 1986. 相似文献