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921.
S Cordel MF Heymann O Boisteau L Oliver J Le Pendu M Grégoire K Meflah 《Canadian Metallurgical Quarterly》1997,73(6):924-928
Advanced colorectal cancer is generally refractory to 5-fluorouracil (5-FU) chemotherapy. This is linked to the emergence of resistant cell populations, probably due to a selection process. The identification of molecular markers and the improvement of alternative therapies thus remain important. We have used as an experimental model a rat colon cancer cell line (PROb), which exhibits features similar to those of the human situation. 5-FU treatment of rats bearing PROb tumors enhanced their survival but did not lead to cure. A PROb 5-FU-resistant subline (PRObR1) was obtained by continuous in vitro exposure to 5-FU. Resistance to 5-FU was accompanied by a 2-fold increase in thymidylate synthase activity and a substantially higher incorporation of thymidine in the presence of 5-FU, compared with parental PROb cells. Unexpectedly, in syngeneic rats, PRObR1 tumors exhibited delayed growth when compared with parental PROb tumors. This was ascribed to an increased sensitivity of PRObR1 cells to host immune response since no growth delay was observed in immunocompromised nude mice and since there was no detectable difference in proliferation rates between PROb and PRObR1 cells. 5-FU treatment was inefficient in prolonging the survival of rats bearing PRObR1 tumors. In contrast, an immunotherapeutic protocol combining sodium butyrate and recombinant interleukin-2 (NaBut/rIL-2) cured 80% of the rats bearing established PRObR1 tumors. Our results suggest that NaBut/rIL-2 treatment is efficient against 5-FU-chemoresistant rat colon cancer. 相似文献
922.
C Aristei F Aversa C Raymondi AR Marsella BM Panizza E Perrucci F Piro E Maranzano M Lupattelli MF Martelli P Latini 《Canadian Metallurgical Quarterly》1996,2(6):330-334
It has been shown that high doses of human recombinant erythropoietin (r epo) increase haemoglobin levels by augmentation of F-cells, and Hb-F production in animal models and in human trials. In this study, r epo was used in patients with beta thalassemia intermedia. Our purpose was to improve haemoglobin levels by at least 2 g and maintain an average level between 10 and 12 g/dl. Ten patients aged 6-29 years (mean 14 +/- 7.6 years) with thalassemia intermedia were treated with r epo. It was given subcutaneously in rising doses from 500 to 1000 U/kg three times weekly for 3 months. During r epo therapy eight cases (80 per cent) showed an increase in haemoglobin, haematocrit, and reticulocyte levels, and an increase of at least 2 g of haemoglobin was obtained. Blood transfusion was not needed during the study except in one case. Five cases (50 per cent) improved life quality with therapy. Hb levels of all patients returned to baseline values over 1 or 2 months after r epo was discontinued. There was no significant change in absolute Hb-F, F-cells, and ferritin levels during treatment. Generally, the drug was well tolerated. No patient had hypertension. Recombinant erythropoietin seems to be an effective treatment for anaemia of beta-thalassemia intermedia, but longer term randomized trials are needed especially in patients with beta thalassemia major. 相似文献
923.
BACKGROUND: Cerebral oedema is a cause of morbidity and mortality in fulminant hepatic failure but has not been well documented as a complication of chronic liver diseases. We report here the development of cerebral oedema and increased intracranial pressure in 12 patients with chronic liver disease. METHODS: Between July 1, 1987, and Dec 31, 1993, we studied 12 patients aged 29-67 years with end-stage chronic liver disease. All the patients had cirrhosis, portal hypertension, hypoprothrombinaemia, hepatic encephalopathy, and decreased serum concentrations of albumin (<25 g/L). During the study, the patients developed signs of increased intracranial pressure and had documented intracranial hypertension, cerebral oedema, or both. Intracranial hypertension was suspected on physical examination and confirmed by epidural catheters. We detected cerebral oedema by computed axial tomography of the head and necropsy of the brain when possible. FINDINGS: All the patients had intracranial hypertension and cerebral oedema. Two patients had successful treatment of cerebral hypertension with improvement of intracranial pressure such that orthotopic liver transplantation was undertaken. Both patients became neurologically normal after transplantation. Eight patients had only a transient response to treatment and died of cerebral oedema before a transplant could be done. INTERPRETATION: Cerebral oedema and increased intracranial pressure can occur in chronic liver disease and presents as neurological deterioration. Treatment guided by monitoring of intracranial pressure can lead to the reversal of intracranial hypertension, but in most patients cerebral oedema contributes to death or places them at too high a risk for liver transplantation. 相似文献
924.
BACKGROUND: The impact of allograft valve viability on valve durability remains controversial. Analyses of our clinical results have demonstrated the superiority of the cryopreserved valve viable at the time of implantation over the 4 degrees C stored valve nonviable at the time of implantation. In this study, we quantitatively assessed the effects on viability of current and past valve-processing protocols at The Prince Charles Hospital. METHODS: The viability of pulmonary valves was quantitatively analyzed by thin-layer autoradiography to assess the effects of donor type, antibiotics, and valve storage. RESULTS: Control valve segments obtained from beating-heart donor valves had a higher initial viability (0.92+/-0.02) than nonbeating-heart donor valves (0.66+/-0.03). Cryopreservation after low-dose antibiotic sterilization significantly reduced viability to 50% to 60% of the control, and in the presence of amphotericin B, viability dropped further to 10% to 36% of the control. After 7 days' storage at 4 degrees C, viability was reduced to 2% of control and to 0% viability after 21 days. CONCLUSIONS: For maximal preimplantation viability, valves should be procured as soon as possible after cessation of heart beat and should be cryopreserved if they are not to be clinically implanted within 1 to 2 days. Amphotericin B should not be used in conjunction with cryopreservation if viability is to be maximized. 相似文献
925.
B Longo-Mbenza M Bayekula R Ngiyulu VE Kintoki NF Bikangi KV Seghers LE Lukoki MF Mandundu M Manzanza Y Nlandu 《Canadian Metallurgical Quarterly》1998,63(3):287-294
Leukocyte adhesion under flow is preferentially mediated by the selectins. In this study we used intravital microscopy to investigate whether E-selectin may promote firm leukocyte adhesion in vivo. E-Selectin is expressed by endothelial cells activated with tumor necrosis factor-alpha (TNF-alpha) and causes slow leukocyte rolling. Microinjection of formyl-methionyl-leucyl-phenylalanine (fMLP) or macrophage inflammatory protein-2 (MIP-2) next to a venule of the TNF-alpha-treated mouse cremaster muscle significantly increased the number of adherent leukocytes. In gene-targeted mice homozygous for a null mutation in the E-selectin gene or in wild-type mice treated with an E-selectin monoclonal antibody (mAb), this response was significantly attenuated (by >80%). No such defect was seen in intercellular adhesion molecule-1 (ICAM-1)-deficient mice. E-Selectin-null mice showed more rapid leukocyte rolling than wild-type or ICAM-1-deficient mice, resulting in significantly shortened leukocyte transit times through venules. Topical application of fMLP onto the whole cremaster muscle generated the same number of adherent leukocytes in wild-type and E-selectin-deficient mice. We conclude that slow leukocyte rolling through E-selectin results in long transit times, which are essential for efficient leukocyte adhesion in response to a local chemotactic stimulus. 相似文献
926.
927.
MF Kronenberg I Laimer C Rifici L Saltuari P Bramanti U Moriggl B Norer A Kofler 《Canadian Metallurgical Quarterly》1998,75(2-3):383-387
We report on two patients with morphine-related seizures associated with either intrathecal or intracerebroventricular administration. Both patients had a history of malignant tumor and both experienced the seizures following bolus application of morphine, while even higher dosages were well tolerated when continuously infused. Seizures occurred without signs of intoxication. Initiation of intrathecal morphine therapy and bolus application should be performed carefully and only when constant monitoring is provided for at least 12 h. Animal data and possible mechanisms for morphine-related seizures are discussed. 相似文献
928.
KB Gale AM Ford R Repp A Borkhardt C Keller OB Eden MF Greaves 《Canadian Metallurgical Quarterly》1997,94(25):13950-13954
Epidemiological evidence has suggested that some pediatric leukemias may be initiated in utero and, for some pairs of identical twins with concordant leukemia, this possibility has been strongly endorsed by molecular studies of clonality. Direct evidence for a prenatal origin can only be derived by prospective or retrospective detection of leukemia-specific molecular abnormalities in fetal or newborn samples. We report a PCR-based method that has been developed to scrutinize neonatal blood spots (Guthrie cards) for the presence of numerically infrequent leukemic cells at birth in individuals who subsequently developed leukemia. We demonstrate that unique or clonotypic MLL-AF4 genomic fusion sequences are present and detectable in neonatal blood spots from individuals who were diagnosed with acute lymphoblastic leukemia at ages 5 months to 2 years and, therefore, have arisen during fetal hematopoiesis in utero. This result provides unequivocal evidence for a prenatal initiation of acute leukemia in young patients. The method should be applicable to other fusion genes in children with common subtypes of leukemia and will be of value in attempts to unravel the natural history and etiology of this major subtype of pediatric cancer. 相似文献
929.
MF McNitt-Gray JG Goldin TD Johnson DP Tashkin DR Aberle 《Canadian Metallurgical Quarterly》1997,21(6):939-947
PURPOSE: Our goal was to develop a protocol and image-processing methods to quantitate both bronchial and lung attenuation changes in patients imaged with helical high-resolution CT (HRCT). METHOD: Human subjects underwent helical HRCT at two suspended breath-hold conditions, functional residual capacity and residual volume, at baseline and following methacholine-induced bronchoprovocation. A semiautomated contouring program was used to define anatomically like bronchi and axial lung sections from the different physiologic sequences, from which automated measurements of area, shape, and attenuation were made. Because the gray level threshold for contouring directly affects the measured area of an anatomic structure, two types of evaluation studies were performed. These included in vivo measurements using baseline parameters of human subjects as the standard of reference and in vitro measurements of a CT phantom designed to simulate the air-soft tissue interfaces of bronchi. RESULTS: Phantom tests showed that the minimum difference between actual and measured areas of holes occurred at a threshold of -500 HU. The smallest diameter holes were most sensitive to changes in threshold value. However, although absolute area measurements of both simulated and human bronchi varied with threshold level, the percent changes in airway areas between baseline and bronchoprovocation sequences were relatively stable at any given threshold. CONCLUSION: These image-processing tools provide reproducible measurements of area as well as attenuation characteristics of pulmonary structures and may offer insights into the practical use of functional imaging in evaluating conditions of airflow obstruction. 相似文献
930.
Ecdysteroid titres have been determined in adult female house crickets (Acheta domesticus) in relation to reproductive maturation. Ecdysteroid levels in newly emerged adult females are low except in the gut and carcass, which probably reflects the remnants of the preecdysial ecdysteroid peak. Ecdysteroid levels in all compartments increase markedly once ovarian weight surpasses 10 mg. Apolar ecdysteroid conjugates (ecdysone 22-fatty acyl esters) predominate in ovarian tissue throughout ovarian maturation, but low levels of free ecdysteroid and polar conjugated ecdysteroids are also present. During this period, two peaks of ecdysteroids (mainly free and apolar conjugated ecdysteroids) are observed in the haemolymph, gut, and carcass compartments. The peaks in the haemolymph occur when the ovarian mass reaches 30 and 100 mg. The gut and carcass may be acting as sinks or sites of metabolism for the hormone released from the ovaries. The rate of ecdysone acylation by ovaries was found to be developmentally regulated, increasing from low levels in the immature ovaries of newly emerged females as the ovaries increase in size. A semiquantitative assay has been developed to identify compounds which inhibit the conversion of [3H]ecdysone into 22-fatty acyl [3H]ecdysone by ovaries in vitro. A number of ecdysteroids possessing a free hydroxyl group as C-22 as well as the side-chain stereochemistry of ecdysone effectively inhibit this conversion, probably by acting as competitive substrates. In the cases of 20-hydroxyecdysone and ponasterone A, it was clearly demonstrated that these compounds are converted to a mixture of C-22 fatty acyl esters. Several other compounds which have been suggested to affect ecdysteroid metabolism/mode of action in other systems were also tested for their effects on the acyltransferase activity of ovaries in vitro. 相似文献