Dioxins were a family of chlorinated aromatic hydrocarbons mainly coming from combustion process with the presence of a chlorine donor and the chlorine-treatment process in chemical industries. Dioxins had been proved to be one of the most toxic materials in environment in recent studies ,and to present carcinogenesis ,teratogenesis ,immunotoxicity,reproductive toxicity and endocrine toxicity ect. With the development of the industrialization ,the dioxins pollution tended to become more and more serious ,which had severely threatened human health. This paper presented a review on the molecular structure,physicochemical characteristics ,pollution sources and degradation ways in environment and impacts of dioxins on human health.

Silencing ATM gene gave rise to enhanced apoptotic response to irradiation and irradiation-like chemotherapy agents, this paper explored the crucial identities of the molecular elements responsible for the enhanced apoptotic response in U937 cells mediated by silencing ATM gene. Two U937 cell mutants named U937-ASPI3K (ATM, negative) and U937-pZeosv2(+) (ATM, wild-type) were used as a cell model system to identify the critical molecule(s) responsible for the varied apoptotic response in the absence or presence of ATM gene. Apoptosis was examined by measuring concentrations of free nucleosome in U937 cells. Western blot was employed to measure nuclear protein abundance of CDC25A, CDC25B, CDC25C, total p34cdc2, p34cdc2, (Thr 161) or p34cdc2 (Thr 14, Tyr 15). RT-PCR was used to estimate CDC25 transcript levels. U937-ASPI3K exhibited an enhanced apoptotic response to lower dosage of irradiation, which could not be blocked by protein synthesis inhibitor. Protein serine-threonine phosphatase inhibitor or cyclin-dependent kinase (CDK) inhibitors, on the other hand, abolished the enhancement indicated that protein phosphorylation/dephosphorylation modification and CDK activity are required for the enhanced apoptotic response in the absence of ATM gene. Upon irradiation, p34cdc2 in U937-pZeosv2(+) was maintained in an inactive state by phosphorylation on threonine 14 (Thr 14) and tyrosine 15 (Tyr 15), which was associated with a dramatic decrease of nuclear CDC25A, CDC25B and CDC25C proteins. In contrast, p34cdc2 in U937-ASPI3K maintained in an active state by dephosphorylation on threonine 14 (Thr 14) and tyrosine 15 (Tyr 15), which was associated with constant nuclear CDC25A, CDC25B and CDC25C protein abundance before and after irradiation. The responsive decrease of nuclear CDC25 proteins occurred at the post-transcription level. Silencing ATM gene blocks the responsive decrease of nuclear CDC25 proteins, which is responsible for failure to inactivate p34cdc2 after irradiation. Active p34cdc2 and CDK2, in turn, acts as the death executors to trigger apoptosis. In summary, aberrantly activated CDK activity is the critical molecular mechanism central to enhanced apoptotic responses in the absence of ATM gene.

[ ABSTRACT] The splicing factors were characterized for their crucial roles in pre-mRNA splicing of eukaryons. SRSF2 is a member of the SR protein family which is one of the most common splicing factors, and it is believed to be a key element in pre-mRNA splicing, mRNA transcription, regulation of the DNA stability and cell proliferation.SRSF2 gene mutation is detected frequently in myeloid malignancies ( like MDS and CMML) and may be associated with the phenotype and prognosis of these malignancies.The paper makes a review for the latest research progression on SRSF2 gene mutation and its relationship with myeloid malignancies.

To investigate the effects of Ligustrazine on histogenesis of bone marrow in the early phase of hematopoietic reconstruction in bone marrow transplantation (BMT) mice. The syngeneic BMT mice model was established. The syngeneic BMT mice were orally given 2 mg Ligustrazine twice a day. 1, 3, 5, 7, 10, 15 and 21 day(s) after BMT, peripheral blood granulocytes and bone marrow nucleated cells (BMNC) were counted and the diameter of central vein and the area of micro-vessel in femur were measured. The effect of Ligustrazine on hematopoietic stem cells was observed by colony forming unit of spleen (CFU-S). The effect of Ligustrazine on hemopoietic progenitors was studied by observing the number of progenitors of Granulocytes/Macrophage on day 10 and day 20 after BMT. In Ligustrazine-treated group, the diameter of center veins and the area of micro-vessel of femur were all significantly less than the control group 7, 10, 15, 21 days after BMT (P < 0.01). In addition, Ligustrazine significantly increased the number of CFU-S on day 10 and the number of CFU-GM on day 10, 20 after BMT. These results indicate that Ligustrazine can accelerate the histogenesis of hemopoietic bone marrow, which may be one mechanism by which Ligustrazine promotes hematopoietic reconstitution after BMT.
*Bone Marrow Transplantation ; Hematopoiesis/*drug effects ; Hematopoietic Stem Cells/*drug effects ; Mice, Inbred BALB C ; Pyrazines/*pharmacology ; Time Factors

Objective To investigate the distribution and antibiotic resistance of the pathogens isolated from blood of the inpatients in hematology ward.Methods Antimicrobial susceptibility test was carried out using Kirby-Bauer method.The data were analyzed by WHONET 5.6 software.Results Of the 521 microbial isolates collected,gram-negative bacilli accounted for 47.2％,grampositive cocci 45.7％ and fungi (7.1％).The most frequently isolated microorganisms were coagulase negative Staphylococcus (154),E.coli (88),K.pneumoniae (51),P.aeruginosa (39) and Enterococcus spp (34).ESBLs were produced in about 40.4％ of the K.pneumoniae isolates and 63.4％ of the E.coli isolates.At least 90％ of the E.coli isolates were susceptible to imipenem and meropenem,and at least 70％ susceptible to piperacillin-tazobactam.At least 85％ of the K.pneumoniae strains were susceptible to imipenem and meropenem,and at least 70％ susceptible to levofloxacin,piperacillin-tazobactam and cefoperazone-sulbactam.The percentage of the P.aeruginosa susceptible to ciprofloxacin and tobramycin was at least 90％,and higher than 70％ to levofloxacin,meropenem,imipenem,piperacillin-tazobactam,cefepime,and cefoperazone-sulbactam.More than 90％ strains of the coagulase negative Staphylococcus and Enterococcus were susceptible to linezolid and teicoplanin.Overall,82.5％ of the coagulase negative Staphylococcus isolates were resistant to methicillin.Three E.coli isolates and 4 K.pneumoniae isolates were found resistant to carbapenems,and 14 Enterococcus isolates were resistant to vancomycin.Conclusions Gram-negative bacilli are the major pathogens from blood samples in hematology ward,which show high susceptibility to piperacillin-tazobactam and cefoperazone-sulbactam,imipenem and meropenem.The grampositive cocci show high susceptibility to linezolid and teicoplanin.These data are helpful for empirical antimicrobial therapy.

The effect of ligustrazine on the expression of CD31 in syngenic bone marrow transplantation (BMT) mice was studied. Fifty-six Balb/c mice were divided into 3 groups: normal control group, BMT control group, and ligustrazine treated group. Syngenic BMT mouse models were established according to the literatures. In BMT control group and the ligustrazine treated group, the mice were given respectively orally 0.2 mL saline and 2 mg ligustrazine twice a day. On the 7th,14th, and 21st day after BMT, the mice were killed. The expression of CD31 on the surface of bone marrow nuclear cells (BMNC) was detected by flow cytometry. Peripheral blood leukocytes, platelets and BMNC were counted. Histological observation of bone marrow was made. The results showed that in ligustrazine treated group the peripheral blood leukocytes, platelets and BMNC counts, and the expression of CD31 on the day 7, 14, 21 after BMT were higher than in BMT control group (P＜0.01 or P＜0.05). In conclusion, ligustrazine could obviously enhance the CD31expression on the surface of BMNC after syngenic BMT in mice, which may be one of the mechanisms underlying the ligustrazine accelerating hematopoietic reconstitution in syngenic BMT.

AIM: To explore the pathogenesis of aplastic anemia (AA), we identified the crucial isoform of cyclin D that determine the proliferation of the cord blood CD34~+ cells and observed effects of AA serum on the expression of crucial cyclin D isoform in umbilical cord blood CD34~+ cells. METHODS: The CD34~+ cells were isolated with MIDI-MACS system. The isoforms of cyclin D were detected by RT-PCR and Western blotting. Methylcellulose culture system was used to measure the formation of CFU-GM. The expression level of crucial cyclin D isoform was assayed by RT-PCR and Western blotting after the CD34~+ cells were incubated in AA serum. RESULTS: The crucial cyclin D isoform in CD34~+ cells was cyclin D3. The AA serum inhibited the formation of CFU-GM and down-regulated expression level of the cyclin D3 from the mRNA to protein level, respectively. CONCLUSION: The AA serum inhibits the proliferation of CD34~+ cells and down-regulates level of cyclin D3, this may be one of hematopoiesis inhibition mechanisms in AA.

The pathogenesis of aplastic anemia (AA) was explored and the effects of AA serum on the expression of crucial cyclin D isoform (cyclin D3) in umbilical cord blood hematopoietic stem/progenitor cells were observed. The CD34+ cells were isolated from the cord blood with MIDI-MACS Semi-solid methylcellulose culture technique was used to measure the formation of CFU-GM; The expression level of cyclin D3 was assayed by semi-quantitative RT-PCR and Western-blot after the hematopoietic stem/progenitor cells were incubated in AA serum. The results showed that the AA serum could inhibit the formation of CFU-GM and down regulate the expression level of the cyclin D3 at the mRNA and protein level respectively. In conclusion, the AA serum could inhibit the proliferation of hematopoietic stem cells and down regulate level of cyclin D3, which might be one mechanism of hematopoiesis inhibition in AA.
Anemia, Aplastic/*blood ; Antigens, CD34/*metabolism ; Cells, Cultured ; Colony-Forming Units Assay ; Cyclins/*biosynthesis ; Cyclins/genetics ; Fetal Blood/cytology ; Hematopoietic Stem Cells/*cytology ; Protein Isoforms/biosynthesis ; Protein Isoforms/genetics ; RNA, Messenger/biosynthesis ; RNA, Messenger/genetics ; Serum

To investigate the effects of Ligustrazine on histogenesis of bone marrow in the early phase of hematopoietic reconstruction in bone marrow transplantation (BMT) mice. The syngeneic BMT mice model was established. The syngeneic BMT mice were orally given 2 mg Ligustrazine twice a day. 1, 3, 5, 7, 10, 15 and 21 day(s) after BMT, peripheral blood granulocytes and bone marrow nucleated cells (BMNC) were counted and the diameter of central vein and the area of micro-vessel in femur were measured. The effect of Ligustrazine on hematopoietic stem cells was observed by colony forming unit of spleen (CFU-S). The effect of Ligustrazine on hemopoietic progenitors was studied by observing the number of progenitors of Granulocytes/Macrophage on day 10 and day 20 after BMT. In Ligustrazine-treated group, the diameter of center veins and the area of micro-vessel of femur were all significantly less than the control group 7, 10, 15, 21 days after BMT (P < 0.01). In addition, Ligustrazine significantly increased the number of CFU-S on day 10 and the number of CFU-GM on day 10, 20 after BMT. These results indicate that Ligustrazine can accelerate the histogenesis of hemopoietic bone marrow, which may be one mechanism by which Ligustrazine promotes hematopoietic reconstitution after BMT.
Animals ; Bone Marrow Transplantation ; Female ; Hematopoiesis ; drug effects ; Hematopoietic Stem Cells ; drug effects ; Male ; Mice ; Mice, Inbred BALB C ; Pyrazines ; pharmacology ; Time Factors

Silencing ATM gene gave rise to enhanced apoptotic response to irradiation and irradiation-like chemotherapy agents, this paper explored the crucial identities of the molecular elements responsible for the enhanced apoptotic response in U937 cells mediated by silencing ATM gene. Two U937 cell mutants named U937-ASPI3K (ATM, negative) and U937-pZeosv2(+) (ATM, wild-type) were used as a cell model system to identify the critical molecule(s) responsible for the varied apoptotic response in the absence or presence of ATM gene. Apoptosis was examined by measuring concentrations of free nucleosome in U937 cells. Western blot was employed to measure nuclear protein abundance of CDC25A, CDC25B, CDC25C, total p34cdc2, p34cdc2, (Thr 161) or p34cdc2 (Thr 14, Tyr 15). RT-PCR was used to estimate CDC25 transcript levels. U937-ASPI3K exhibited an enhanced apoptotic response to lower dosage of irradiation, which could not be blocked by protein synthesis inhibitor. Protein serine-threonine phosphatase inhibitor or cyclin-dependent kinase (CDK) inhibitors, on the other hand, abolished the enhancement indicated that protein phosphorylation/dephosphorylation modification and CDK activity are required for the enhanced apoptotic response in the absence of ATM gene. Upon irradiation, p34cdc2 in U937-pZeosv2(+) was maintained in an inactive state by phosphorylation on threonine 14 (Thr 14) and tyrosine 15 (Tyr 15), which was associated with a dramatic decrease of nuclear CDC25A, CDC25B and CDC25C proteins. In contrast, p34cdc2 in U937-ASPI3K maintained in an active state by dephosphorylation on threonine 14 (Thr 14) and tyrosine 15 (Tyr 15), which was associated with constant nuclear CDC25A, CDC25B and CDC25C protein abundance before and after irradiation. The responsive decrease of nuclear CDC25 proteins occurred at the post-transcription level. Silencing ATM gene blocks the responsive decrease of nuclear CDC25 proteins, which is responsible for failure to inactivate p34cdc2 after irradiation. Active p34cdc2 and CDK2, in turn, acts as the death executors to trigger apoptosis. In summary, aberrantly activated CDK activity is the critical molecular mechanism central to enhanced apoptotic responses in the absence of ATM gene.
Apoptosis ; drug effects ; genetics ; radiation effects ; Ataxia Telangiectasia Mutated Proteins ; CDC2 Protein Kinase ; metabolism ; Cell Cycle Proteins ; Cyclin-Dependent Kinases ; metabolism ; DNA-Binding Proteins ; Gene Silencing ; drug effects ; radiation effects ; Humans ; Protein-Serine-Threonine Kinases ; genetics ; Tumor Suppressor Proteins ; U937 Cells ; cdc25 Phosphatases ; metabolism