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21.
TL Holyoake MG Freshney L McNair AN Parker PJ McKay WP Steward E Fitzsimons GJ Graham IB Pragnell 《Canadian Metallurgical Quarterly》1996,87(11):4589-4595
The characterization of many cytokines involved in the control of hematopoiesis has led to intense investigation into their potential use in ex vivo culture to expand progenitor numbers. We have established the optimum ex vivo culture conditions that allow substantial amplification of transient engrafting murine stem cells and which, simultaneously, augment the ability to sustain serial bone marrow transplantation (BMT). Short-term incubation of unfractionated BM cells in liquid culture with stem cell factor (SCF) and interleukin-11 (IL-11) produced a 50-fold amplification of clonogenic multipotential progenitors (CFU-A). Following such ex vivo expansion, substantially fewer cells were required to rescue lethally irradiated mice. When transplanted in cell doses above threshold for engraftment, BM cells expanded ex vivo resulted in significantly more rapid hematopoietic recovery. In a serial transplantation model, unmanipulated BM was only able to consistently sustain secondary BMT recipients, but BM expanded ex vivo has sustained quaternary BMT recipients that remain alive and well more than 140 days after 4th degree BMT. These results show augmentation of both short-term recovery posttransplant and the ability to serially transplant marrow by preincubation in culture with SCF and IL-11. 相似文献
22.
C Alli F Avanzini G Bettelli M Bonati F Colombo R Corso M Di Tullio MG Gentile L Sangalli E Taioli 《Canadian Metallurgical Quarterly》1992,6(4):281-286
The present study set out to assess the feasibility of long-term moderate dietary sodium restriction in patients with mild hypertension in general practice. After screening and a run-in phase of 6-8 weeks, a total of 77 previously undiagnosed mildly hypertensive patients were identified. Half of them were randomized to receive a few simple dietary instructions from their general practitioners in order to reduce salt usage; the others were randomized to receive no advice. The patients were followed up for 12 months with quarterly visits. A total of 56 patients (72.7%) completed the study, 26 on a low-sodium diet (LD) and 30 on their usual diet (UD). At each visit in the diet phase, patients provided 24h urine, which was analysed for volume and sodium concentration in order to assess their sodium intake. Blood pressure, heart the rate and body weight were recorded. The mean urinary sodium excretion for all diet phase visits overlapped in the two groups (177.0 +/- 32.9 vs. 169.3 +/- 49.4 mEq/24h respectively in the LD and UD groups). Nevertheless the mean systolic and diastolic blood pressures for all diet phase visits were significantly lower in the LD than in UD group (144.2 +/- 11.1/91.6 +/- 6.4 and 148.0 +/- 13.7/95.6 +/- 4.7 mmHg respectively, P less than 0.01). Our data suggest that it is not feasible at present to reduce sodium intake in mild hypertensives with simple and inexpensive dietary instructions, the only ones suitable for widespread application in general practice. 相似文献
23.
Compound LB20304 is a fluoronaphthyridone carboxylic acid with a novel pyrrolidine substituent. This drug was compared with ciprofloxacin, levofloxacin, ofloxacin, and trovafloxacin against over 800 pathogens, most from blood stream infections, by National Committee for Clinical Laboratory Standards reference methods. LB20304 was the most active agent against gram-positive species including strains observed to be resistant to other fluoroquinolones and glycopeptides. The potency of LB20304 (MIC50, 0.03 micrograms/ml) against the Enterobacteriaceae was exceeded only by that of ciprofloxacin (0.015 micrograms/ml). It has limited activity against gram-negative anaerobes. 相似文献
24.
The influence of the nicotine antagonist dihydro-beta-erythroidine (DH beta E) was examined on various behavioural effects of nicotine in rats. Motor activity was recorded in photocell cages whereas discriminative stimulus effects were examined using two-lever drug discrimination procedures with a tandem schedule of food reinforcement (n = 8 throughout). DH beta E (0.1-3.2 mg/kg) failed to antagonise the decreases in motor activity that nicotine (0.4-0.6 mg/kg) produced in experimentally naive rats, whereas mecamylamine (1.5 mg/kg) completely blocked this effect of nicotine. DH beta E (0.1-3.2 mg/kg) antagonised the increases in motor activity that nicotine (0.4 mg/kg) produced in rats with extensive previous exposure to both nicotine and the photocell apparatus. In rats trained to discriminate either 0.1 or 0.4 mg/kg nicotine from saline, DH beta E (0.1-3.2 mg/kg) blocked the discriminative stimulus effect of nicotine. The block of the discriminative effect could be reversed by increasing the dose of nicotine; DH beta E (1.6 mg/kg) shifted the dose-response curve for nicotine discrimination to the right by a factor of 9.4. In addition, nicotine in doses of 0.32-0.64 mg/kg decreased the overall rate of lever pressing but DH beta E (1.6 mg/kg) did not influence the dose-response curve for this effect. Thus, DH beta E potently blocked the locomotor activating and discriminative stimulus effects of nicotine at doses that did not antagonise its locomotor depressant and operant response rate-reducing effects. This selective blockade supports the involvement of different subtypes of nicotinic receptor in the mediation of diverse behavioural effects. Furthermore, the rightward shift of the dose-response curve for nicotine discrimination suggested a competitive mode of action for DH beta E. 相似文献
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MG Narducci L Virgilio JB Engiles AM Buchberg L Billips A Facchiano CM Croce G Russo JL Rothstein 《Canadian Metallurgical Quarterly》1997,15(8):919-926
In human leukemias and lymphomas nonrandom chromosomal rearrangements cause changes in cell growth and/or survival in such a way as to promote malignancy. The detailed study of the biochemical and genetic pathways altered in human cancer requires the identification or development of models to allow the study and manipulation of cancer gene function. Recently, the breakpoint gene TCL1, involved in chromosome translocations observed mostly in mature T-cell proliferations and chronic lymphocytic leukemias (CLL), was isolated and characterized, and showed to be part of a new gene family of proteins involved in these tumors. The murine Tcl1 gene, is similar in sequence to the murine and human MTCP1 gene also involved in T cell leukemias. The murine Tcl1 gene was shown to reside on mouse chromosome 12 in a region syntenic to human chromosome 14. Furthermore, we show that the murine Tcl1 gene is expressed early in mouse embryonic development and demonstrates expression in fetal hematopoietic organs as well as in immature T and B cells. Characterization of the murine Tcl1 gene will help in developing a mouse model of CLL and would provide the best opportunity to study and decipher the role of TCL1 in malignant transformation. 相似文献
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