Role of B7-1 in mediating an immune response to myeloid leukemia cells

A costimulatory signal from B7-1 (CD80) to its counter-receptor CD28 is required for T-cell activation. Many tumors, including most human leukemias, lack expression of B7-1, and this has been suggested to contribute to the failure of immune recognition of these diseases. A murine leukemia model system was developed to assess the potential role of B7-1 in the induction immunity to leukemia cells. The nonleukemic 32Dc13 myeloid cell line was transformed by transfection of the BCR/ABL gene, generating a subline (32Dp210/clone 26) that was leukemic and rapidly lethal to syngeneic, immunocompetent C3H/HeJ mice or T-cell- deficient nude mice. B7-1-modified leukemic cells remained lethal in nude mice, but caused only a transient, nonlethal leukemia in C3H/HeJ mice. After a single exposure to live, nonirradiated B7-1-modified leukemic cells, C3H/HeJ mice developed protective immunity against subsequent challenge with B7-1(-) leukemic cells. Further, hyperimmunization with B7-1(+) leukemic cells prolonged the survival of mice previously injected with a lethal number of B7-1(-) leukemic cells. These results indicate that myeloid leukemic cells may be attractive candidates for B7-1 gene transfer.     

Levels and membrane localization of the c-K-ras p21 protein in lungs of mice of different genetic strains and effects of 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) and Aroclor 1254

Mutational activation of the K-ras oncogene often occurs in human and mouse lung adenocarcinomas. Since K-ras p21 functions in trans-membrane signaling, we have investigated whether the amount of this protein in lung cell membranes is a variable that could influence lung tumorigenesis, either due to genetic differences or in response to tumor promoters. The six mouse strains assessed showed little difference in the total lung K-ras p21 after immunoprecipitation and immunoblotting. However, amount of ras p21 in the membrane fraction showed significant differences, with C57BL/6 and BALB/c having 3-5-fold more than NIH Swiss, AKR and DBA mice. Interestingly, a congenic AKR strain having the Ahr(b-1) Ah receptor allele from C57BL/6 mice (designated AKR.B6Ah) had high lung membrane K-ras p21 similar to that of C57BL/6. To test for possible changes related to lung tumor promotion, mice were treated with a promotional dose of TCDD (5 nmol/kg). After 48 h C57BL/6 lungs showed an increase in p21 in both total and membrane fractions. BALB/c, DBA and Swiss mice showed an increase only in membranes. There was no change in the AKR and AKR.B6Ah. Aroclor 1254 (250 mg/kg) caused an increase in membrane/cytosol ratio in Swiss mice. Thus the membrane:cytosol K-ras p21 ratio may be influenced by the Ahr phenotype, and TCDD and PCBs can induce p21 or increase its membrane level in certain strains, but these properties are not fully dependent on Ahr receptor type. In confirmation of the relevance of these findings for the tumor target cell type, the immortalized alveolar type 2 E10 cell line presented K- ras p21 in membrane, and this was increased 4-fold by treatment with 10 nM TCDD.      

催醒安在大鼠尿内代谢产物的研究

催醒安是一种新的中枢性抗胆碱酯酶药。给大鼠灌胃后,用HPLC分离纯化尿提取液中的代谢产物,得到四个组分。经MS鉴定分别为原形药物,N-羟甲基,N-甲基氨基甲酸-[间-(2-二甲氨基)]乙氧基苯酯(简称羟基化催醒安),N-甲基氨基甲酸-[间-(2-二甲氨基)乙氧基]苯酯(去甲基催醒安)及间-(2-二甲氨基)乙氧基苯酚(催醒安水解物)。原药及产物对电鳐乙酰胆碱酯酶抑制率的实验表明,去甲基催醒安抑酶活性与原药相近,羟基化催醒安活性比原药低,水解物无抑酶活性。     

HPLC柱切换法血浆直接进样测定氟康唑

建立了用HPLC柱切换测定血浆中氟康唑的方法。血样用0.2mol·L^-1醋酸溶液简单稀释后注入填充LiChromprepRP2(25～40μm)的预柱上,用蒸馏水冲洗出血浆中蛋白和其它极性成分。切换后,浓缩在预柱上的氟康唑被流动相甲醇-0.2mol·L^-1醋酸按(pH2.7)(50:50)反冲到分析柱ShimpackCLC-ODS上进行分析。预柱用净化液进行清除和再生。本法有很好的精密度与回收率,检测限为0.12μg·mL^-1血浆,日间和日内测定相对标准偏差均小于6%。此分析法已成功地用于测定自愿受试者的氟康唑药代动力学及生物利用度。     

Adult asthma review in general practice: nurses' perception of their role

BACKGROUND: Asthma clinics have become widespread in general practice with nurses now playing an important role in asthma review. However, little is known about training of nurses carrying out reviews and how this affects the nurse role in patient management. OBJECTIVES: We aimed to discover the level of asthma training of practice nurses carrying out review of adult asthma patients in one Health Authority and to see if this has any effect on their perception of their role. METHOD: All 187 practice nurses in Grampian were sent a postal questionnaire investigating how asthma review is organized in general practice, their role in review and the asthma training they had received. Personal interviews were carried out with 17 nurses, exploring in more depth the topics covered in the questionnaire. RESULTS: A total of 167 nurses from 92% of the practices in Grampian responded, of whom 61% carried out asthma reviews. Among nurses carrying out reviews 71% did so on their own. 49% of nurses had or were training for advanced asthma qualification. Nurses without an asthma qualification were significantly more likely to feel that their training was not sufficient for their asthma related tasks (54% versus 11%, P = 0.0002). Nurses without advanced asthma qualifications were less likely to provide or review a self-management plan (29% versus 49%, P = 0.01), to review patient PEF recording (38% versus 65%, P < 0.01), to discuss patient worries (75% versus 94%, P < 0.05) or to make the initial diagnosis of asthma (24% versus 76%, P < 0.005). Nurses were unlikely to view their role as fully responsible unless they had an asthma qualification (13% versus 49%, P < 0.001). CONCLUSION: Nurses without advanced asthma qualifications do not feel fully confident in responsibility for patient management. Nurses without training are more likely to only carry out routine monitoring at reviews while nurses with asthma training are more likely to actively develop patient self- management skills. This suggests that nurses should be supported to obtain asthma qualifications if they are to give the best possible care to asthma patients.      

Analysis of tissue-specific lacZ mutations induced by N- nitrosodibenzylamine in transgenic mice

N-Nitrosodibenzylamine (NDBzA) is a contaminant found frequently in rubber baby bottle nipples and pacifiers. To evaluate more fully the mutagenic potential and analyse the molecular nature of possible mutations induced in vivo, we have studied the mutagenicity of NDBzA in vivo using the MutaMouse system. NDBzA, suspended in olive oil, was administered orally once to male mice at different doses (0, 30, 100, 425 and 750 mg/kg) and the mice were killed 30 and 90 days after treatment. As a positive control, and to compare relative mutagenicity, N-nitrosodimethylamine (NDMA) was also administered to animals in the same experiment at doses of 0, 2, 6 and 10 mg/kg. Mutant frequencies were increased in both 30 and 90 day liver samples, but not in bone marrow, after both NDBzA and NDMA treatment. However, NDBzA was >100 times less mutagenic than NDMA. A total of 81 mutants obtained from liver samples of treated animals (750 mg/kg) were characterized by DNA sequencing. While spontaneous mutations in transgenic mice have been characterized previously by a preponderance of G:C-->A:T transitions, mainly at 5'-CpG-3' dinucleotide sites, the predominant type of NDBzA- induced mutation in this study was transversion, mainly G:C-->T:A changes. The molecular characteristics of mutations induced by NDBzA indicate that they may arise from specific unidentified DNA adducts and benzylation appears to be the primary mechanism involved in formation of these DNA adducts.      

Enzymes involved in the bioactivation of 4-(methylnitrosamino)-1-(3- pyridyl)-1-butanone in patas monkey lung and liver microsomes

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent tobacco-specific carcinogen in animals. Our previous studies indicated that there are differences between rodents and humans for the enzymes involved in the activation of NNK. To determine if the patas monkey is a better animal model for the activation of NNK in humans, we investigated the metabolism of NNK in patas monkey lung and liver microsomes and characterized the enzymes involved in the activation. In lung microsomes, the formation of 4-oxo-1-(3-pyridyl)-1-butanone (keto aldehyde), 4-(methylnitrosamino)-1-(3-pyridyl-N-oxide)-1-butanone (NNK- N-oxide), 4-hydroxy-1-(3-pyridyl)-1-butanone (keto alcohol), and 4- (methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) was observed, displaying apparent Km values of 10.3, 5.4, 4.9, and 902 microM, respectively. NNK metabolism in liver microsomes resulted in the formation of keto aldehyde, keto alcohol, and NNAL, displaying apparent Km values of 8.1, 8.2, and 474 microM, respectively. The low Km values for NNK oxidation in the patas monkey lung and liver microsomes are different from those in human lung and liver microsomes showing Km values of 400-653 microM, although loss of low Km forms from human tissue as a result of disease, surgery or anesthesia cannot be ruled out. Carbon monoxide (90%) significantly inhibited NNK metabolism in the patas monkey lung and liver microsomes by 38-66% and 82-91%, respectively. Nordihydroguaiaretic acid (a lipoxygenase inhibitor) and aspirin (a cyclooxygenase inhibitor) decreased the rate of formation of keto aldehyde and keto alcohol by 10-20 % in the monkey lung microsomes. Alpha-Napthoflavone and coumarin markedly decreased the oxidation of NNK in monkey lung and liver microsomes, suggesting the involvement of P450s 1A and 2A6. An antibody against human P450 2A6 decreased the oxidation of NNK by 12-16% and 22-24% in the patas monkey lung and liver microsomes, respectively. These results are comparable to that obtained with human lung and liver microsomes. Coumarin hydroxylation was observed in the patas monkey lung and liver microsomes at a rate of 16 and 4000 pmol/min/mg protein, respectively, which was 5-fold higher than human lung and liver microsomes, respectively. Immunoblot analysis demonstrated that the P450 2A level in the individual patas monkey liver microsomal sample was 6-fold greater than in an individual human liver microsomal sample. Phenethyl isothiocyanate, an inhibitor of NNK activation in rodents and humans, decreased NNK oxidation in the monkey lung and liver microsomes displaying inhibitor concentration resulting in 50% inhibition of the activity (IC50) values of 0.28-0.8 microM and 4.2-6.8 microM, respectively. The results demonstrate the similarities and differences between species in the metabolic activation of NNK. The patas monkey microsomes appear to more closely resemble human microsomes than mouse or rat enzymes and may better reflect the activation of NNK in humans.