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91.
The two-stage transformation assay increases the sensitivity of cells to chemicals and permits detection of carcinogens acting as initiating agents. 1,2-Dibromoethane, a representative halogenated aliphatic, has been tested in the two-stage BALB/c 3T3 cells transformation test at dosages from 16 μM to 128 μM. This dose range is much lower than those previously found efficient in transforming BALB/c 3T3 cells. Apart from the lowest dose, which induced borderline effects, all the other assayed dosages appeared to induce heritable changes in the traget cells. The initiated cells were revealed as fully transformed foci both in the combination with a chronic promoting treatment and also by allowing cells to perform more rounds of cell replication. The results clearly show that 1,2-dibromo-ethane can act as an initiator of cell transformation.  相似文献   
92.
The shape of the erythrocytes can be altered by a great variety of chemical agents, such as many detergents due to their amphiphilic nature. The present study examines the effect of an anionic detergent on the shape of mature, circulating catfish red blood cells. Experimental exposure to sodium dodecyl benzene sulphonate dissolved in the water of aquaria at two sublethal concentrations (1.5 and 3 ppm), for a maximum of 15 days, induced morphological changes of normal erythrocyte shape to echinocytic form. These changes were evaluated at 5, 10 and 15 days after the start of treatment, using scanning electron microscopy. The crenated erythrocytes from animals exposed to detergent appeared either with border irregularities or undulations, without distinct spicules, or with numerous short spikes. Statistical analysis, applied to the data obtained from counting altered cells in the various experimental groups, showed no significant difference between the 1.5 ppm-treated animals at the three times and the controls, whereas a significant difference was observed between 3 ppm-treated animals compared to the controls, showing significance of action of the higher dose employed at the three times. These data suggest latent erythrocyte damage. The results are discussed in the light of the extensive bibliography concerning evaginating amphiphilic compounds and the mechanisms involved in echinocyte formation, taking into account the marked differences existing between the nucleated red blood cells of fish and those biconcave, unnucleated of mammals.  相似文献   
93.
CCK-15, a peptide derived from the 115-membered CCK preprohormone, was the object of a comparative conformational analysis by NMR spectroscopy and molecular modeling methods. NMR data in several solvents demonstrate that the propensity of the peptide to fold into a helical conformation is intrinsic, not merely a consequence of the interaction with phosphatidylcholine micelles or with a putative receptor, as suggested by a previous study on CCK-8 (Pellegrini, M.; Mierke, D. Biochemistry 1999, 38, 14775-14783.). The prevailing CCK-15 conformer in a mixture 1,1,1,3,3,3-hexafluoroacetone/water reveals that the residues common to CCK-15 and CCK-8 assume very similar conformations. Our CCK-15 structure is consistent with the model of receptor interaction proposed by Pellegrini and Mierke and discloses possible novel interactions that involve a larger area of the putative receptor. The consensus structure between CCK-15 and CCK-8 shows a good superposition of the side chains of residues 12-14 with crucial moieties of two non-peptidic CCK-A antagonists.  相似文献   
94.
BACKGROUND: One third of cadaveric kidney transplant recipients suffer graft loss within five years of transplantation. Non-immunologic factors that predict mortality among non-transplant patients also may be potentially modifiable risk factors for mortality among patients with transplant failure. METHODS: Applying multivariate survival analysis to data from the United States Renal Data System, we determined the effect of immunologic or transplant related factors and non-immunologic factors on mortality in patients who initiated dialysis after kidney transplant failure in the United States between April 1995 and September 1998. RESULTS: A total of 4741 patients were followed for a median +/- standard deviation of 15 +/- 11 months after initiation of dialysis after transplant failure. The majority of the 1016 (21%) deaths were due to cardiac (36%) or infectious (17%) causes. Patients in the following groups had an increased risk for all-cause mortality: older patients [hazard ratio (HR) = 1.04 per year, 95% confidence interval (95% CI) 1.03-1.04], women (HR = 1.31, 95% CI 1.10-1.56), patients of white race (HR = 1.94, 95% CI 1.32-2.84), patients with diabetes (HR = 1.76, 95% CI 1.43-2.16), peripheral vascular disease (HR = 1.94, 95% CI 1.54-2.43), congestive heart failure (HR = 1.26, 95% CI 1.05-1.53), drug use (HR = 2.23; 95% CI 1.08-4.60), smokers (HR = 1.35, 95% CI 1.01-1.81), first transplant recipients (HR = 1.32, 95% CI 1.02-1.69), and patients with a higher glomerular filtration rate (GFR) at dialysis initiation (HR = 1.04 per mL/min higher, 95% CI 1.02-1.06). Those with private insurance (HR = 0.67, 95% CI 0.49-0.93) and higher serum albumin (HR = 0.73 per g/dL higher, 95% CI 0.64-0.83) had a decreased risk for all-cause mortality. Acute rejection, antibody induction, donor source, duration of graft survival and the maximum attained GFR during transplantation did not predict all-cause mortality. CONCLUSIONS: Non-immunologic factors predicted mortality among patients with transplant failure but immunologic and transplant related factors did not. Prevention, early diagnosis and treatment of co-morbid conditions and the complications of chronic kidney disease may improve the survival of patients with transplant failure.  相似文献   
95.
Constitutive bcl-2 overexpression increases the tumorigenic and metastatic potential of doxorubicin-resistant, estrogen-independent, MCF-7 ADR human breast cancer cells. We evaluated the sensitivity to taxanes (paclitaxel, docetaxel and IDN 5109) of 2 bcl-2-overexpressing MCF-7 ADR clones and control neomycin-transfected MCF-7 ADR neo cells. The 2 bcl-2-overexpressing MCF-7 ADR clones were relatively resistant to all 3 taxanes, whereas the MCF-7 ADR neo cells were relatively resistant to paclitaxel and docetaxel, but sensitive to IDN 5109. We found that both MCF-7 ADR neo and bcl-2-overexpressing MCF-7 ADR clones express high levels of the epidermal growth factor receptor (EGFR) and its ligand, transforming growth factor-alpha (TGF-alpha). Therefore, we tested the growth inhibitory effect of ZD1839 (Iressa, AstraZeneca, Macclesfield, UK), an orally active, selective EGFR tyrosine kinase inhibitor (EGFR-TKI) that is in clinical development. ZD1839 inhibited the growth in soft agar of all 3 clones in a dose-dependent manner (IC(50) of approximately 0.1 microm). This effect was accompanied by a dose-dependent inhibition of EGFR tyrosine autophosphorylation and of the production of TGF-alpha, basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF). To determine whether the blockade of EGFR signaling might affect the sensitivity of bcl-2-overexpressing MCF-7 ADR cells to taxanes, cells were treated with ZD1839 in combination with paclitaxel, docetaxel or IDN 5109, and dose-dependent cooperative growth inhibition as well as apoptosis potentiation were observed. Combined treatment with IDN 5109 and ZD1839 also resulted in a significant inhibition of bcl-2 expression in bcl-2-overexpressing MCF-7 ADR cells. These results demonstrate the ability of ZD1839 to overcome taxane resistance in a model of hormone-independent, multidrug-resistant, human breast cancer.  相似文献   
96.
There is an increased risk of cancer after organ transplantation mainly due to the immunosuppressive therapy required in these patients. We report a case of biphasic pulmonary blastoma in an adult male who underwent liver transplant for hepatocellular carcinoma in March 1999, followed by immunosuppressive treatment and adjuvant chemotherapy with epirubicin. Disease-free survival lasted 18 months, then a diagnosis of biphasic pulmonary blastoma was made and the patient underwent a lung lobectomy. Five months after surgical resection a recurrence of this rare tumor was recorded and two cycles of cisplatin + etoposide and ifosfamide + etoposide and one cycle of second-line chemotherapy with vinorelbine were administered. The tolerability and the efficacy of this treatment were poor. The patient died less than one year after diagnosis. To our knowledge this is the first reported case of pulmonary blastoma in a transplant patient. Our findings confirm that organ transplant recipients deserve long-term medical surveillance also in the absence of graft complications, and that pulmonary blastoma is an aggressive tumor with a poor prognosis.  相似文献   
97.
OBJECTIVE: In 1994 we mailed questionnaires to referral centers in Italy in order to evaluate the different opinions concerning aspects of endometrial cancer treatment, which is still controversial. The data processing showed a significant nonhomogeneity in disease management and prompted the Italian Society of Gynecologic Oncology to define guidelines for endometrial cancer adjuvant treatment. In 2001, we mailed again the same questionnaire to the same referral Centers in Italy. The aim of the second enquiry was the evaluation of changes in endometrial cancer management and the effective impact of the guidelines published. METHODS: The enquiry used the same questionnaires mailed in 1994; actually, we mailed those questionnaires to the same referral centers in Italy twice: in December 2000 and March 2001.The results of both the enquiries were collected in a relational data base, and the statistical evaluations were calculated using SPSS-statistics (Window ver. 8). RESULTS: Endometrial cancer treatment consists in abdominal hysterectomy and bilateral salpingo-oophorectomy. The unique relevant difference as to 1994 consists in the systemic performing of peritoneal cytology in endometrial cancer staging. Unlike the previous enquiry, adjuvant radiotherapy is not systematically performed in disease at stage Ic because of the substantial absence of confirmed data demonstrating a real benefit in terms of survival rate.The comparison between the two enquiries shows a significant change in medical planning and diversification attitude according to patient age and menopausal state. The disease management changes in patients over 75 years old, mainly with respect to surgery and primary therapy. CONCLUSIONS: We noted a resistance of many centers to accept some trends actually widespread in the literature but not yet performed in practical clinical.  相似文献   
98.
99.
BACKGROUND/AIMS: The aim of this study was to evaluate functional results after Billroth I, Billroth II and Roux-en-Y reconstruction in subtotal gastrectomy. METHODOLOGY: Forty-five patients were randomized between 1990 and 1995 and stratified in 3 different groups: 15 BI, 15 BII and 15 Roux. They were investigated by esophagogastroduodenoscopy with multiple biopsies and upper gastrointestinal scintiscanning, to evaluate gastroesophageal reflux and dynamics of gastric emptying. They also answered a questionnaire: Gastrointestinal Quality of Life. Index. RESULTS: A reflux esophagitis was found in 5 BI, in 7 BII and in 2 Roux (p < 0.001). No gastric lesions were found in 6 BI, in 5 BII and in 12 Roux, (BI vs. Y, p < 0.05; BII vs. Y, p < 0.001). Chronic superficial gastritis was present in 9 BI, in 4 BII and in 3 Roux (BI vs. Y, p < 0.05). Dynamic scintiscan demonstrated the presence of gastroesophageal reflux in 5 BI and gastric emptying was fast (37' < T 1/2 < 86'), but incomplete (60' residual activity: 49-62%). Gastroesophageal reflux was evident in 7 BII with slow (28' < T 1/2 < 143') and incomplete (60' residual activity: 48-72%) gastric emptying. Gastroesophageal reflux was detected in 2 Roux and radioactive bolus progression in the Roux limb was fast (24' < T 1/2 < 53') and complete (60' residual activity: 42-52%) (BI vs. Y; BII vs. Y, p < 0.001). There was no statistical significance between Gastrointestinal Quality of Life Index score in the 3 groups. CONCLUSIONS: The Authors affirm that Roux-en-Y is the technique of choice in subtotal gastrectomy, if compared with BI and BII.  相似文献   
100.
In this study we report previously undescribed associations between mutations, haplotypes and a minisatellite polymorphism (Hind III VNTR) of the PAH gene in the Sicilian population. Analysis of the association between mutations and linked polymorphisms between Sicilians and other Mediterranean populations may be a useful tool to study the time-space origin of mutant PAH genes in Southern Europe.  相似文献   
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