Selective inhibition of the bacterial translocase reaction in peptidoglycan synthesis by mureidomycins.

Mureidomycins (MRDs) A and C inhibited strongly the formation of undecaprenyl pyrophosphoryl N-acetylmuramyl-pentapeptide (lipid intermediate I), which is an intermediate in bacterial peptidoglycan synthesis (50% inhibitory concentration [IC50] of MRD A, 0.05 microgram/ml). However, they did not inhibit the formation of dolichyl pyrophosphoryl N-acetylglucosamine (Dol-p-p-GlcNAc), dolichyl phosphoryl glucose, or dolichyl phosphoryl mannose, the precursors for mammalian glycoprotein synthesis, or the formation in Bacillus subtilis of lipid-linked N-acetylglucosamine for teichoic acid synthesis (IC50s, > 100 micrograms/ml). In contrast, tunicamycin (TCM) inhibited strongly the formation of Dol-p-p-GlcNAc (IC50, 0.03 microgram/ml) but inhibited weakly the formation of bacterial lipid intermediate I (IC50, 44 micrograms/ml). When the effects of MRDs A and C and TCM on the growth of mammalian cells were compared, MRDs did not show any toxicity, even at 1,000 micrograms/ml, whereas TCM inhibited the growth of BALB/3T3 cells at 10 micrograms/ml. On the basis of these results, it was concluded that MRDs are the first specific and potent inhibitors of the translocase reaction in bacterial peptidoglycan synthesis, showing a high level of toxicity against bacteria and a low level of toxicity against mammalian cells. A specific inhibitor of translocase could be a potent antibiotic with highly selective toxicity.     

On the Mechanism of Action of Vancomycin: Inhibition of Peptidoglycan Synthesis in Gaffkya homari

Vancomycin inhibits the synthesis of peptidoglycan in membrane preparations from Gaffkya homari with uridine diphosphate-N-acetylmuramyl (UDP-Mur-NAc)-pentapeptide as substrate, but not with either UDP-MurNAc-tetrapeptide or UDP-MurNAc-tripeptide. These results are correlated with the specificity studies described by Perkins and Nieto for complex formation between the antibiotic and the peptide subunit. It is concluded that the formation of a complex between vancomycin and a postulated cell wall acceptor or between vancomycin and the enzymes involved in peptidoglycan synthesis does not contribute to the inhibitory action of this antibiotic. The mechanism of vancomycin action on peptidoglycan synthesis is clearly different from that of moenomycin and bacitracin. In the presence of these antibiotics, peptidoglycan synthesis is inhibited with both UDP-MurNAc-pentapeptide and -tetrapeptide as substrates. In addition, these results provide additional insight into the mechanism of phospho-MurNAc-pentapeptide translocase. For example, enhancement of the transfer of phospho-MurNAc-peptide from UDP-MurNAc-peptide to undecaprenyl-phosphate at low concentrations of vancomycin is observed with UDP-MurNAc-pentapeptide and not with -tetrapeptide. Complexation of vancomycin with undecaprenyl-diphosphate-MurNAc-pentapeptide, resulting in an ineffective intermediate, would increase the rate of transfer by preventing the reassociation of undecaprenyl-diphosphate-MurNAc-pentapeptide with the enzyme.     

Inhibition of bacterial isoprenoid synthesis by fosmidomycin, a phosphonic acid-containing antibiotic

The mechanism of action of fosmidomycin (FR-31564), a phosphonic acid containing antibiotic, was examined against Escherichia coli, Micrococcus luteus and other bacteria. It converted growing Esch. coli cells into spheroplasts or swollen cells, but did not inhibit the enzymatic reactions of cell wall synthesis in ether-treated cells. Unlike bicyclomycin, phenethyl alcohol and mitomycin C, it did not reduce the amount of envelope lipoprotein, phospholipids, or DNA, but did reduce the amount of menaquinones and ubiquinones in growing Esch. coli cells. It also inhibited the biosynthesis of both carotenoids and menaquinones in M. luteus cells, suggesting that inhibition of the biosynthesis of a common precursor of these isoprenoids (possibly farnesyl pyrophosphate) might be the main site of its antibacterial activity.     

多发性骨髓瘤流式细胞术免疫表型及微量残留病研究

目的 探讨MM细胞免疫表型特征及MRD检测的临床意义.方法 应用多参数流式细胞术检测16名健康对照者和172例MM患者的免疫表型.32例MM患者缓解后作MRD分析,同时进行跟踪随访,分析MRD阳性和阴性对MM患者的复发率和无病生存时间是否存在影响.结果 流式细胞术检测结果显示,16名健康对照者正常浆细胞CD38、CD 138、CD19、CD45均阳性,172例MM患者骨髓瘤细胞主要免疫表型为CD+38 172例(100.0%)、CD+138172例(100.0%)、CD-19 167例(97.1%)、CD+56 152例(88.4%)、CD-45 166例(96.5%),骨髓瘤细胞具有显著的特征性表型,即CD+38、CD+138、CD+56、CD-19、CD-45.32例MM患者缓解后进行MRD检测,其中14例MRD阴性,18例MRD阳性.随访2～16个月后,MRD阴性组4例复发(28.6%),MRD阳性组13例复发(72.2%),两组复发率比较,差异有统计学意义(χ2=6.03,P＜0.05).MRD阴性组累积无病生存时间中位数16.23(10.37～21.62)个月,明显长于MRD阳性组的10.07(3.79～16.20)个月,两组比较差异有统计学意义(χ2=7.53,P＜0.05).结论 MM患者骨髓瘤细胞主要免疫表型特征是CD+38、CD+138、CD1-19、CD-45、CD+56.多发性骨髓瘤MRD检测可以作为临床预后的参考指标.

Abstract：

Objective To investigate the characteristics of immunophenotyping and clinical significance of MRD analysis in MM patients. Methods Multi-parameter flow cytometry was applied to analyze the immunophenotyping of malignant plasma cells from 172 MM patients, and normal plasma cells from 16 healthy individuals. MRD was analyzed in 32 MM patients with remission. Meanwhile, the effects of MRD status on the disease relapse and patient disease free survival ( DFS ) time was evaluated by following up patients. Results The immunophenotyping of normal plasma cells were CD38, CD138, CD19 and CD45 positive, while the predominant phenotype of MM cells were CD+38( 100.0% ), CD+138( 100.0% ), CD-19 ( 167/172, 97. 1% ), CD+56( 152/172, 88.4% ) and CD-45( 166/172, 96. 5% ). The characteristic markers for MM cells were CD+38, CD-138, CD-19, CD-45 and CD+56. MRD analysis revealed that, among 32 MM patients with remission, 14 patients were MRD negative and 18 patients were MRD positive. During follow-up of 2 to 16 months, the relapse rate in MRD negative patients was significantly lower ( 4/14, 28.6% ) than that of MRD positive patients ( 13/18, 72. 2% ;χ2 =6. 03, P ＜0. 05 ). Furthermore, the DFS time was significantly longer in MRD negative patients[ 16. 23( 10. 37-21.62 )months ] than that of the MRD positive patients [ 10. 07( 3. 79-16. 20 )months,χ2 =7. 53,P ＜0. 05 ]. Conclusions CD+38, CD+138, CD-19, CD-45 and CD+56 are the characteristic markers of MM cells compared to those of the normal plasma cells. MRD analysis is a valuable prognostic factor for MM patients.     

Antigens of leukemias induced by naturally occurring murine leukemia virus: their relation to the antigens of gross virus and other murine leukemia viruses

Leukemias can be induced in W/Fu inbred rats by neonatal inoculation of normal thymus cells of C58 mice. These leukemias are not transplantable to C58 mice or to adult W/Fu rats, but they can be kept in passage in W/Fu rats aged 0 to 7 days. Adult W/Fu rats inoculated repeatedly with these isogenic leukemias produce cytotoxic and precipitating antibodies. These antisera are of particular value in the analysis of the antigens of leukemia cells and of leukemia viruses because their mode of preparation precludes the formation of antibody against any normal constituents of the cell. Analysis based on the cytotoxic test indicates the presence of 2 distinct cell surface antigens in leukemias induced by Passage A Gross virus or occurring spontaneously in mice of high-incidence strains. All leukemias and other tissues known to contain G (Gross) leukemia antigen have both determinants, but certain leukemias of low-incidence strains have only 1 of them and so were previously classified G-. Immunoprecipitation with these antisera reveals the presence of a cellular antigen common to G+ cells and absent from G- cells; the same antigen can be demonstrated in ether-treated Gross virus, but not in intact virus. This antigen is present also in ether-treated preparations of the Friend, Moloney, and Rauscher leukemia viruses, but not in Bittner (mammary tumor) virus. Thus it may be regarded as a group-specific antigen of murine leukemia viruses, in contrast to the type-specific cellular antigens demonstrable by the cytotoxic test. Four additional antigens associated with leukemias induced by wild-type Gross virus have been demonstrated by immunoprecipitation, but their relation to viral and cellular antigens has not been determined.     

四色流式细胞术检测B细胞急性淋巴细胞白血病微量残留病的临床意义

目的探讨利用四色流式细胞术（FCM）检测B细胞急性淋巴细胞白血病（B-ALL）微量残留病（MRD）的临床意义.方法采用以抗CD34/CD10/CD45/CD19为主的两种四色荧光标记抗体组合,对98例B-ALL患者的671份骨髓标本和1份脑脊液标本进行FCM多参数MRD检测,98例随访患者中26例无发病初期的免疫分型资料.结果FCM检测显示白血病细胞＜0.0001（MRD阴性）的标本为579份;白血病细胞＞0.0001的样本数为93份,其中64份骨髓标本白血病细胞比例＜0.05,29份标本白血病细胞比例＞0.05,我们将其归为复发病例（包括治疗后未达CR的病例）.共20例患者复发,其中19例血液学复发,1例中枢神经系统复发.15例血液学复发者在复发前7～17周发现MRD阳性,包括发病时免疫分型资料不明者6例,MRD水平均＞0.0001;2例分别在复发前3个月和9个月检测MRD为阴性,此后中断检测.在诱导治疗结束和治疗3个月时,如果MRD水平＞0.0001,复发率为50%（12例中有6例复发）,而MRD阴性组复发率为7.5%（40例中有3例复发）（P=0.000）.结论利用FCM进行MRD跟踪监测可预测复发,治疗初期患者MRD＞0.0001,复发的危险性较高.而在掌握了正常B祖细胞抗原表达规律的基础上,可不完全依赖于发病时的免疫表型资料.     

Detection of minimal residual disease in peripheral blood prior to clinical relapse of childhood acute lymphoblastic leukaemia using PCR

Submicroscopic evidence of persistent minimal residual disease (MRD) in first remission bone marrow samples from children with acute lymphoblastic leukaemia (ALL) indicates a high risk of clinical relapse. Since microscopic evidence of leukaemic lymphoblasts is often present in the peripheral blood in the weeks before clinical presentation at diagnosis or relapse, peripheral blood may be used instead of bone marrow to detect MRD in ALL patients. We examined a median of 0.165 microg (from 1.0-2.0x10(4)cells) genomic DNA from archived peripheral blood smears collected 8-16 months prior to clinical relapse in eight children with ALL for evidence of MRD. We used the polymerase chain reaction and primers designed to identify clonal antigen receptor gene rearrangements. Among the seven patients with bone marrow relapse, MRD was detected at a median of 1.2 months (0-8 months) prior to clinical relapse, indicating that MRD in the peripheral blood may be a late event in the course of leukaemic relapse. A prospective MRD study in ALL patients analysing larger numbers of peripheral blood cells will be needed to evaluate the utility of peripheral blood over bone marrow for MRD testing in childhood ALL.     

Association of clinical status of follicular lymphoma patients after autologous stem cell transplant and quantitative assessment of lymphoma in blood and bone marrow as measured by SYBR Green I polymerase chain reaction

Molecular remission in the autograft and bone marrow after transplant are predictive of durable clinical remission in relapsed follicular lymphoma. Thus, a simple reliable method to quantify minimal residual disease (MRD) would improve prognostication in these patients. Fluorescent hybridization probes have been used in real-time quantitative polymerase chain reaction (RQ-PCR) to monitor MRD with a reproducible sensitivity of 0.01%; however, these techniques are expensive and require additional experiments to examine clonality. We describe a SYBR Green I detection method that is more universal, checks clonal identity, yields the same sensitivity for monitoring MRD, and is more economically attractive. Using this method to follow 14 follicular lymphoma patients treated with autologous stem cell transplantation, molecular markers were successfully defined for 12 patients. Median contamination of stem-cell grafts was 0.1% (range, 0 to 13%). Six patients with measurable graft contamination became PCR-negative in blood and bone marrow within 12 months after autologous stem cell transplantation. Three patients free of disease progression (median follow-up of 75 months) are in molecular remission. Increasing fractions of RQ-PCR-positive blood and bone marrow cells reliably predicted morphological and clinical relapse. In one case, both clinical relapse and spontaneous regression were reflected by changes in MRD levels. Thus, our RQ-PCR method reproducibly distinguishes different levels of MRD.     

Detection of minimal residual disease in patients with acute myeloid leukemia

AIM: Detection of minimal residual disease (MRD) in patients with acute myeloid leukemia (AML) and the study of its correlations with duration of recurrence-free interval. MATERIAL AND METHODS: Bone marrow samples obtained from 37 AML patients before treatment were studied at two-color flow cytometry. The panel of monoclonal antibodies to T- and B-cell, myeloid antigens was used. The residual cells were estimated in 20 patients in remission. RESULTS: 78% cases were diagnosed to have an anomalous immunophenotype including coexpression of lymphoid and myeloid antigens, asynchronous expression of myeloid antigens. In the first remission the residual cells were detected in 20 patients due to aberrant antigen expression. The presence of MRD was stated if bone marrow contained more than 0.12% leukemic cells. The duration of the first remission and MRD correlated. 8 patients with MRD had remission for 3 to 6 months (median 4.7 months). 12 patients free of MRD were in remission for more than 6 months (for 8 to 26 months, median 19.7 months). The threshold level of the residual cells (0.12%) was confirmed statistically using the three-parameter probability model. CONCLUSION: This study confirms feasibility of using flow cytometry for detection of residual cells. MRD and duration of the first remission correlate. Long-term observation of large groups of AML patients will try the validity of the above statistical model.     

流式细胞术定期监测微量残留病可预测急性白血病复发——单中心163例研究

目的 研究急性白血病(AL)在化疗获得第1次完全缓解( CR1)后用流式细胞术(FCM)定期监测微量残留病(MRD)的预后价值.方法 对2005年4月至2009年7月北京市道培医院收治的CR1期AL患者(不包括接受造血干细胞移植者),定期用FCM监测患者骨髓MRD,追踪至复发或至2010年7月.根据每例患者的白血病特点选择抗体组合,MRD≥0.01％为阳性,否则为阴性.用Kaplan-Meier法统计持续完全缓解(CCR)率,用Log-rank检验方法比较MRD阳性与阴性患者CCR率差异.结果 163例患者中急性髓系白血病(AML) 108例,急性B淋巴细胞白血病(B-ALL)55例.89例AML患者在诊断后1年内接受MRD监测,根据化疗至12个月时的MRD检测结果将患者分为MRD阳性及阴性组:30例MRD阳性者中仅3例CCR至2010年7月,24、36个月的CCR率分别为13％、13％;59例MRD阴性者中47例CCR至2010年7月,24、36个月的CCR率分别为94％、78％;两组CCR率差异有统计学意义(P＜0.01).35例B-ALL患者在诊断后5个月内接受MRD监测,根据MRD检测结果将患者分为MRD阳性及阴性组:13例MRD阳性者无一例CCR至2010年7月,24、36个月的CCR率为0;22例MRD阴性者中20例CCR至2010年7月,24、36个月的CCR率均为96％;两组CCR率差异有统计学意义(P＜0.01).超过以上监测时间MRD阳性的其他患者均复发,而MRD持续阴性者很少复发.结论 用FCM定期监测AL的MRD有良好的预后价值.     

CD+4 Foxp3+调节性T淋巴细胞在儿童急性白血病中的表达及其与微小残留病的关系

目的 研究调节性T淋巴细胞(regulatory T cell,Treg)在白血病患者体内的表达情况,探讨Treg的增高与白血病疗效监测与白血病微小残留病(minimal residual disease,MRD)预后指标之间的关系.方法 建立Foxp3-FITC/CD-25PE/CD4-PerCP/CD3-APC四色流式细胞术检测Treg的方法 ;比较10例正常骨髓标本以及33例白血病初发患者[急性B淋巴细胞白血病(B-ALL)17例,急性T淋巴细胞白血病(T-ALL)9例,急性髓细胞白血病(AML)7例]骨髓标本中Treg的数量;结合56例临床缓解患者MRD监测结果 ,评估Treg作为白血病患者预后判断评价指标的价值.结果 正常骨髓组Treg占CD+4T淋巴细胞的比例中位数(M)为8.09%,初发自血病组M为12.77%,两者差异有统计学意义(U=3.41,P<0.01);而在B-ALL、T-ALL和AML组的差异无统计学意义(H=1.22,P>0.05).Treg数量与临床病理学参数无显著相关性.此外,Treg数量在MRD阳性组(M=14.74%)与MRD持续阴性组(M=11.3%)中的差异有统计学意义(t=252.5,P<0.05).结论 白血病初发患儿体内的Treg数量显著增高,且患儿中Treg表达水平与MRD有关联.高水平Treg预示白血病患儿预后较差,存在复发的可能.     

儿童急性淋巴细胞白血病微小残留病的流式细胞术分析

目的 根据白血病细胞的异常免疫表达,建立流式细胞术检测儿童急性淋巴细胞白血病(acute lymphoblastic leukemia,ALL)微小残留病(minimal residual disease,MRD)的方法 ,探讨流式细胞术检测MRD在儿童ALL个体化治疗中的意义.方法 用流式细胞术以多种四色荧光抗体组合对健康儿童骨髓进行检测,建立健康儿童骨髓细胞双参数点图分析模板.对75例ALL初诊患儿的骨髓细胞进行MRD筛选,找出在双参数点图上的位置明显区别于正常骨髓细胞的免疫表型组合作为MRD监测的有效免疫表型组合,对其中60例患儿诱导治疗结束及后续治疗中的骨髓标本用这些有效免疫表型组合进行MRD监测.同步进行细胞形态学检测和PCR检测29种融合基因、IgH/T淋巴细胞受体(TCR)基因重排.结果流式细胞术检出69例(92.0%)可用于MRD监测的有效免疫表型组合,PCR检出21例(28.0%)可用于MRD监测的融合基因或IgH/TCR基因重排;诱导治疗结束后及后续治疗中有25份骨髓标本细胞形态学未检出白血病残留细胞,流式细胞术检测仍有0.021%～4.130%的白血病残留细胞.结论 流式细胞术检测儿童ALL MRD能较好地评估临床缓解期间ALL患儿体内残留白血病细胞的数量,其覆盖面和速度优于PCR检测方法 ,敏感性高于形态学检测方法 .     

儿童急性淋巴细胞白血病微小残留病的流式细胞术分析

目的 根据白血病细胞的异常免疫表达,建立流式细胞术检测儿童急性淋巴细胞白血病(acute lymphoblastic leukemia,ALL)微小残留病(minimal residual disease,MRD)的方法 ,探讨流式细胞术检测MRD在儿童ALL个体化治疗中的意义.方法 用流式细胞术以多种四色荧光抗体组合对健康儿童骨髓进行检测,建立健康儿童骨髓细胞双参数点图分析模板.对75例ALL初诊患儿的骨髓细胞进行MRD筛选,找出在双参数点图上的位置明显区别于正常骨髓细胞的免疫表型组合作为MRD监测的有效免疫表型组合,对其中60例患儿诱导治疗结束及后续治疗中的骨髓标本用这些有效免疫表型组合进行MRD监测.同步进行细胞形态学检测和PCR检测29种融合基因、IgH/T淋巴细胞受体(TCR)基因重排.结果流式细胞术检出69例(92.0%)可用于MRD监测的有效免疫表型组合,PCR检出21例(28.0%)可用于MRD监测的融合基因或IgH/TCR基因重排;诱导治疗结束后及后续治疗中有25份骨髓标本细胞形态学未检出白血病残留细胞,流式细胞术检测仍有0.021%～4.130%的白血病残留细胞.结论 流式细胞术检测儿童ALL MRD能较好地评估临床缓解期间ALL患儿体内残留白血病细胞的数量,其覆盖面和速度优于PCR检测方法 ,敏感性高于形态学检测方法 .     

动态监测儿童B系急性淋巴细胞白血病微量残留病的临床意义

目的 探讨动态监测儿童白血病微量残留病(MRD)对指导B系急性淋巴细胞白血病(B-ALL)治疗的临床意义.方法 以2004年1月至2009年12月确诊并完成诱导治疗的81例B-ALL患儿作为研究对象.初诊时用流式细胞术(FCM)筛选白血病细胞标志,随后定时随访.结果 81例患儿中80例诱导治疗获缓解,5年无事件生存(EFS)率为(76.80±5.70)%,其中标危组(89.40±5.90)%,中危组(66.99±13.60)%.81例患儿中68例筛选出特异性白血病细胞抗原作为MRD监测标志,13例未筛选出特异性白血病细胞抗原标志,两者5年EFS率分别为(79.10 ±6.20)%和(62.50±15.10)%,差异无统计学意义(P>0.05).诱导治疗第35天MRD检测显示68例患儿中MRD阴性(残留白血病细胞<0.01%)52例,5年EFS率为(88.50±4.90)%;MRD阳性(残留白血病细胞≥0.01%)16例,5年EFS率为(42.10±20.10)%,差异具有统计学意义(P<0.05),单因素分析提示MRD监测结果与危险度分层相关.诱导治疗第55天MRD监测显示,诱导第35天MRD阴性的52例患儿中,51例仍为阴性,1例阳性;而16例MRD阳性患者中14例(87.50%)转为阴性,2例仍阳性(后经加强治疗转为阴性).68例缓解患儿1年内MRD阳性9例(3例复发),1年后MRD阳性4例(2例复发),持续MRD阴性55例(4例复发).差异有统计学意义(P<0.05).结论 动态监测B-ALL患儿MRD,可判断预后,及时调整治疗方案,具有重要临床意义.

Abstract：

Objective To study the clinical significance of sequentially monitoring minimal residual disease( MRD)in childhood B-cell acute lymphoblastic leukemia( B-ALL). Method Eighty one B-ALL cases were enrolled in the study from January 2004 to December 2009. Leukemia cell markers were detected by flow cytometry at diagnosis, then regularly followed-up. Results Of 81 cases, 80 achieved complete remission (CR) after induction therapy, 5-year event-free survival (EFS) was (76.80 ±5.70)%. Among them, the EFS was (89.40±5.90) % in standard risk group and(66.99 ±13.60)% in intermediate risk group. Eight cases were screened for leukemia markers for MRD monitoring and identified in 68; and 5-year EFS was (79. 10 ±6.20) % and (62.50 ± 15. 10) % (P>0.05, respectively). MRD detection at day 35 in induction therapy showed that 52 of 68 cases were MRD negative (leukemia cells < 0.01%), the 5-year EFS being (88. 50 ± 4. 90)% , and 16 were MRD positive (leukemia cells ≥ 0. 01% ), the 5-year EFS being (42. 10±20. 10)% (P>0. 05). Univariate analysis confirmed that there was a correlation between MRD monitoring and risk stratification. MRD detection at day 55 showed that among the 52 day 35 MRD negative cases, 51 were still negative, 1 positive, among 16 day 35 MRD positive cases, 14(87. 50% ) turned negative, 2 still positive. Of the 68 cases, 9 were MRD positive within one year after CR (3 relapsed), 4 MRD positive after one year (2 relapsed) and 55 MRD negative (4 relapsed) (P > 0.05). Conclusions Sequential monitoring MRD can find out treatment outcome and adjust therapy in time.     

CD10在儿童期B-急性淋巴细胞白血病中的表达特点及其在微小残留病检测中的意义

本研究的目的是观察CDl0在儿童期B急性淋巴细胞白血病(BALL)中的表达情况，并探讨CDl0在白血病微小残留病检测中的应用价值。用流式细胞术分析58例儿童期急性淋巴细胞白血病表型，观察CDl0在BALL病例骨髓细胞中的表达特点，并将CDl0抗体与其它多种抗体构成四色组合用于B-ALL的微小残留病检测，评价其所起到的作用。结果表明，65、5％(38／58)的BALL具有CDl0过强表达(CDl0^bright)的特点，而且CDl0^bright与CD34的阳性表达率有关——CDl0^bright多出现于CD34阳性率高的B-ALL中。CDl0^bright在微小残留病检测中，与其它异常表达的抗原形成的组合能够在双参数点图上很好地区分出白血病细胞群与正常细胞群。即使在其他抗原表达无异常时，也可因CDl0的过强表达而使白血病细胞群与正常细胞群区分开。结论：CDl0^bright与BALL中CD34的高比例表达相关，CDl0^bright也是微小残留病检测的一个很好的指标，CDl0的表达与其他用于微小残留病检测的抗原表达的应用有互补作用。     

四色流式细胞术检测急性B淋巴细胞白血病残留细胞

目的探讨利用多参数流式细胞术检测急性B淋巴细胞白血病(BALL)残留细胞的方法和意义。方法采用四色流式细胞术,以4～6组四色抗体组合检测213例BALL患者免疫分型;以CD34、CD10、CD45、CD19为主的2种四色荧光标记抗体组合监测50例297份BALL患者骨髓标本微量残留白血病细胞,同时检测分析26份化疗后处于再生期骨髓标本中B祖细胞的免疫表型特点,并以相对定量方法比较了再生期B祖细胞与B系白血病细胞CD10、CD19和CD34表达量的差异。结果213例BALL患者中,71.8%患者存在CD45、CD34、CD19、CD10表达量的异常,只存在CD38弱阳性及髓系标志患者占8.1%。微量残留白血病细胞监测的50例患者中,12例患者存在0.06%～7.73%的白血病细胞,其中11例残留白血病细胞以CD45、CD34、CD19、CD10异常表达为主。50例患者中5例临床复发,4例在复发前7～17周微量残留病(MRD)检测阳性,且均>0.1%,1例MRD检测阴性。再生期B祖细胞依据CD45、CD34、CD19、CD10、CD22和CD20表达不同可分为3期。结论多参数流式细胞术检测MRD具有快速、敏感可定量的优势,对白血病复发有更强的预测性。     

STUDIES ON IMMUNE HEMOLYSIS: PREPARATION OF A STABLE AND HIGHLY REACTIVE COMPLEX OF SENSITIZED ERYTHROCYTES AND THE FIRST COMPONENT OF COMPLEMENT (EAC'1); INACTIVATION OF CELL-FIXED C'1 BY SOME COMPLEMENT REAGENTS

The interaction of sensitized sheep crythrocytes (EA) with guinea pig complement inactivated by treatment with hydrazine or ether has been studied. In both cases EA is converted into EAC'1. The hemolytic reactivity of this complex with respect to a complement reagent that contains C'4, C'2, and C'3 (R1) decays rapidly in the presence of hydrazine-treated complement (R4) or decomplemented guinea pig serum, but not in the presence of ether-treated guinea pig serum or of saline. The rate of decay of EAC'1 is dependent on the temperature, the reaction volume, and the amount of the inactivating reagent. The capacity of R4 and of decomplemented serum to inactivate EAC'1 can be markedly reduced by treatment with ether. The essential conditions for obtaining an optimally reactive EAC'1 consist in exposing EA to ether-treated guinea pig serum in the cold. This procedure yields a highly reactive EAC'1, even when the cells are sensitized with suboptimal amounts of amboceptor.     

Susceptibility of Pseudomonas species to the novel antibiotics mureidomycins.

Strains of Pseudomonas aeruginosa, including imipenem- or ofloxacin-resistant clinical isolates, and some other species in the genus Pseudomonas were inhibited by novel antibiotics of the mureidomycin (MRD) group. On the other hand, almost all other gram-positive and gram-negative bacteria were resistant to MRDs, though the antibiotics potently inhibited the in vitro peptidoglycan synthesis of Escherichia coli and P. aeruginosa. All of the strains in the genus Pseudomonas that were inhibited by less than or equal to 200 micrograms of MRDs per ml were classified into the rRNA groups I and III, and none of the tested strains of rRNA group I were resistant to MRDs, suggesting that these two groups are closely related to each other evolutionary. Among group I strains, P. aeruginosa, P. mendocina, P. stutzeri, and P. alcaligenes were more susceptible than the others, suggesting a closer relationship among these species.     

A MurF inhibitor that disrupts cell wall biosynthesis in Escherichia coli

MurF is an essential enzyme of bacterial cell wall biosynthesis. Few MurF inhibitors have been reported, and none have displayed measurable antibacterial activity. Through the use of a MurF binding assay, a series of 8-hydroxyquinolines that bound to the Escherichia coli enzyme and inhibited its activity was identified. To derive additional chemotypes lacking 8-hydroxyquinoline, a known chelating moiety, a pharmacophore model was constructed from the series and used to select compounds for testing in the MurF binding and enzymatic inhibition assays. Whereas the original diverse library yielded 0.01% positive compounds in the binding assay, of which 6% inhibited MurF enzymatic activity, the pharmacophore-selected set yielded 14% positive compounds, of which 37% inhibited the enzyme, suggesting that the model enriched for compounds with affinity to MurF. A 4-phenylpiperidine (4-PP) derivative identified by this process displayed antibacterial activity (MIC of 8 microg/ml against permeable E. coli) including cell lysis and a 5-log(10)-unit decrease in CFU. Importantly, treatment of E. coli with 4-PP resulted in a 15-fold increase in the amount of the MurF UDP-MurNAc-tripeptide substrate, and a 50% reduction in the amount of the MurF UDP-MurNAc-pentapeptide product, consistent with inhibition of the MurF enzyme within bacterial cells. Thus, 4-PP is the first reported inhibitor of the MurF enzyme that may contribute to antibacterial activity by interfering with cell wall biosynthesis.