Flagellimonas halotolerans sp. nov., a novel bacterium isolated from the South China Sea.

Two Gram-stain-negative strains, designed SYSU M86414T and SYSU M84420, were isolated from marine sediment samples of the South China Sea (Sansha City, Hainan Province, PR China). These strains were aerobic and could grow at pH 6.0-8.0 (optimum, pH 7.0), 4-37 °C (optimum, 28 °C), and in the presence of 0-10 % NaCl (w/v; optimum 3 %). The predominant respiratory menaquinone of strains SYSU M86414T and SYSU M84420 was MK-6. The primary cellular polar lipid was phosphatidylethanolamine. The major cellular fatty acids (>10 %) in both strains were iso-C15 : 0, iso-C15 : 1 G, and iso-C17 : 0 3-OH. The DNA G+C content of strains SYSU M86414T and SYSU M84420 were both 42.10 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that these novel strains belonged to the genus Flagellimonas and strain SYSU M86414T showed the highest 16S rRNA gene sequence similarity to Flagellimonas marinaquae JCM 11811T (98.83 %), followed by Flagellimonas aurea BC31-1-A7T (98.62 %), while strain SYSU M84420 had highest 16S rRNA gene sequence similarity to F. marinaquae JCM 11811T (98.76 %) and F. aurea BC31-1-A7T (98.55 %). Based on the results of polyphasic analyses, strains SYSU M86414T and SYSU M84420 should be considered to represent a novel species of the genus Flagellimonas, for which the name Flagellimonas halotolerans sp. nov. is proposed. The type strain of the proposed novel isolate is SYSU M86414T (=GDMCC 1.3806T=KCTC 102040T).

Relationship between chorioamnionitis or funisitis and lung injury among preterm infants: meta-analysis involved 16 observational studies with 68,397 participants.

BACKGROUND: Chorioamnionitis (CA) can cause multiple organ injuries in premature neonates, particularly to the lungs. Different opinions exist regarding the impact of intrauterine inflammation on neonatal respiratory distress syndrome (NRDS) and bronchopulmonary dysplasia (BPD). We aim to systematically review the relationship between CA or Funisitis (FV) and lung injury among preterm infants. METHODS: We electronically searched PubMed, EMbase, the Cochrane library, CNKI, and CMB for cohort studies from their inception to March 15, 2023. Two reviewers independently screened literature, gathered data, and did NOS scale of included studies. The meta-analysis was performed using RevMan 5.3. RESULTS: Sixteen observational studies including 68,397 patients were collected. Meta-analysis showed CA or FV increased the lung injury risk (OR = 1.43, 95%CI: 1.06-1.92). Except for histological chorioamnionitis (HCA) (OR = 0.72, 95%CI: 0.57-0.90), neither clinical chorioamnionitis (CCA) (OR = 1.86, 95%CI: 0.93-3.72) nor FV (OR = 1.23, 95%CI: 0.48-3.15) nor HCA with FV (OR = 1.85, 95%CI: 0.15-22.63) had statistical significance in NRDS incidence. As a result of stratification by grade of HCA, HCA (II) has a significant association with decreased incidence of NRDS (OR = 0.48, 95%CI: 0.35-0.65). In terms of BPD, there is a positive correlation between BPD and CA/FV (CA: OR = 3.18, 95%CI: 1.68-6.03; FV: OR = 6.36, 95%CI: 2.45-16.52). Among CA, HCA was positively associated with BPD (OR = 2.70, 95%CI: 2.38-3.07), whereas CCA was not associated with BPD (OR = 2.77, 95%CI: 0.68-11.21). HCA and moderate to severe BPD (OR = 25.38, 95%CI: 7.13-90.32) showed a positive correlation, while mild BPD (OR = 2.29, 95%CI: 0.99-5.31) did not. CONCLUSION: Currently, evidence suggests that CA or FV increases the lung injury incidence in premature infants. For different types of CA and FV, HCA can increase the incidence of BPD while decreasing the incidence of NRDS. And this "protective effect" only applies to infants under 32 weeks of age. Regarding lung injury severity, only moderate to severe cases of BPD were positively correlated with CA.

Mechanism of the Allergenicity Reduction of Ovalbumin by Microwave Pretreatment-Assisted Enzymolysis through Biological Mass Spectrometry.

Ovalbumin (OVA) is a major allergen in hen eggs. Enzymolysis has been demonstrated as an efficient method for reducing OVA allergenicity. This study demonstrates that microwave pretreatment (MP) at 400 W for 20 s assisting bromelain enzymolysis further decreases the allergenicity of OVA, which was attributed to the increase in the degree of hydrolysis and promoted the destruction of IgE-binding epitopes. The results showed that MP could promote OVA unfolding, expose hydrophobic domains, and disrupt tightly packed α-helical structures and disulfide bonds, which increased the degree of hydrolysis by 7.28% and the contents of peptides below 1 kDa from 43.55 to 85.06% in hydrolysates compared with that for untreated OVA. Biological mass spectrometry demonstrated that the number of intact IgE-binding epitope peptides in MP-assisted OVA hydrolysates decreased by 533 compared to that in hydrolysis without MP; consequently, their IgG/IgE binding rates decreased more significantly. Therefore, MP-assisted enzymolysis may provide an alternative method for decreasing the OVA allergenicity.

Cereibacter flavus sp. nov., a novel member of the family Rhodobacteraceae isolated from seawater of the South China Sea and reclassification of Rhodobacter alkalitolerans as Cereibacter alkalitolerans comb. nov.

A Gram-stain-negative, aerobic, motile, ovoid-shaped and yellow-coloured strain, designated SYSU M79828T, was isolated from seawater collected from the South China Sea. Growth of this strain was observed at 4-37 °C (optimum, 28 °C), pH 6.0-8.0 (optimum, pH 7.0) and with 0-6% NaCl (optimum, 3.0 %, w/v). The respiratory quinone was found to be Q-10. Major fatty acid constituents were C18 : 1 ω7c/C18 : 1 ω6c, C18 : 1 ω7c11-methyl and C18 : 0 (>5 % of total). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphoglycolipid, two unidentified phospholipid, one unidentified lipid and an unidentified glycolipid. The genomic DNA G+C content was 64.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that strain SYSU M79828T belonged to the genus Cereibacter and had the highest sequences similarity to 'Rhodobacter xinxiangensis' TJ48T (98.41 %). Based on 16S rRNA gene phylogeny, physiological and chemotaxonomic characterizations, we consider that strain SYSU M79828T represents a novel species of the genus Cereibacter, for which the name Cereibacter flavus sp. nov. is proposed. The type strain is SYSU M79828T (=GDMCC 1.3803T=KCTC 92893T). In addition, according to the results of phylogenetic analysis and similar taxonomic characteristics, we propose that Rhodobacter alkalitolerans should be reclassified as Cereibacter alkalitolerans comb. nov.

The joint effect of ultrasound and magnetic Fe3O4 nanoparticles on the yield of 2,6-dimethoxy-ρ-benzoquinone from fermented wheat germ: Comparison of evolutionary algorithms and interactive analysis of paired-factors.

2,6-Dimethoxy-ρ-benzoquinone (DMBQ) is a potential anti-tumor substance found in the fermented wheat germ. In this study, ultrasound and Fe3O4 nanoparticles were used to improve the DMBQ yield. An artificial neural network (ANN) embedded separately with the back-propagation algorithm (BP), genetic algorithm (GA), particle swarm optimized algorithm (PSO), ant colony optimized algorithm (ACO), GA-ACO, GA-PSO and PSO-ACO, were used to establish the relationship between 11 factors and DMBQ yield. The robustness and generalization of PSO-ACO-ANN, which gave the minimum mean squared error and mean absolute percentage error for the training and test dataset, was superior to the others. Next, a modified Garson's algorithm and mixed partial derivatives algorithm indicated that the most influential paired-parameters were ultrasonic power and concentration of nanoparticles. Finally, the factors were optimized by six optimization algorithms, and confirmatory experimental results indicated that the optimum DMBQ yield was 0.213 ±â€¯0.007 mg/g, which was 161.2% higher than the control.

MicroRNA-1269 promotes cell proliferation via the AKT signaling pathway by targeting RASSF9 in human gastric cancer.

BACKGROUND: MicroRNAs (miRNAs) play key roles in tumorigenesis and progression of gastric cancer (GC). miR-1269 has been reported to be upregulated in several cancers and plays a crucial role in carcinogenesis and cancer progression. However, the biological function of miR-1269 in human GC and its mechanism remain unclear and need to be further elucidated. METHODS: The expression of miR-1269 in GC tissues and cell lines was detected by quantitative real-time PCR (qRT-PCR). Target prediction programs (TargetScanHuman 7.2 and miRBase) and a dual-luciferase reporter assay were used to confirm that Ras-association domain family 9 (RASSF9) is a target gene of miR-1269. The expression of RASSF9 was measured by qRT-PCR and Western blotting in GC tissues. MTT and cell counting assays were used to explore the effect of miR-1269 on GC cell proliferation. The cell cycle and apoptosis were measured by flow cytometry. RASSF9 knockdown and overexpression were used to further verify the function of the target gene. RESULTS: We found that miR-1269 expression was upregulated in human GC tissues and cell lines. The overexpression of miR-1269 promoted GC cell proliferation and cell cycle G1-S transition and suppressed apoptosis. The inhibition of miR-1269 inhibited cell growth and G1-S transition and induced apoptosis. miR-1269 expression was inversely correlated with RASSF9 expression in GC tissues. RASSF9 was verified to be a direct target of miR-1269 by using a luciferase reporter assay. The overexpression of miR-1269 decreased RASSF9 expression at both the mRNA and protein levels, and the inhibition of miR-1269 increased RASSF9 expression. Importantly, silencing RASSF9 resulted in the same biological effects in GC cells as those induced by overexpression of miR-1269. Overexpression of RASSF9 reversed the effects of miR-1269 overexpression on GC cells. Both miR-1269 overexpression and RASSF9 silencing activated the AKT signaling pathway, which modulated cell cycle regulators (Cyclin D1 and CDK2). In contrast, inhibition of miR-1269 and RASSF9 overexpression inhibited the AKT signaling pathway. Moreover, miR-1269 and RASSF9 also regulated the Bax/Bcl-2 signaling pathway. CONCLUSIONS: Our results demonstrate that miR-1269 promotes GC cell proliferation and cell cycle G1-S transition by activating the AKT signaling pathway and inhibiting cell apoptosis via regulation of the Bax/Bcl-2 signaling pathway by targeting RASSF9. Our findings indicate an oncogenic role of miR-1269 in GC pathogenesis and the potential use of miR-1269 in GC therapy.

MiR-637 suppresses melanoma progression through directly targeting P-REX2a and inhibiting PTEN/AKT signaling pathway.

MicroRNAs (miRNAs) play important roles in melanoma. Although miR-637 has been suggested to be a tumor suppressor in several cancers, its function in melanoma and the molecular mechanism behind that function remain unclear. In this study, we investigated the role of miR-637 in human melanoma and explored its relevant mechanisms. We found that the expression of miR-637 is significantly downregulated in melanoma tissues and cell lines. While overexpression of miR-637 inhibited melanoma cell proliferation and cell cycle G1-S transition, and induced apoptosis. Inhibition of miR-637 promoted cell proliferation and G1-S transition, and suppressed apoptosis. Subsequent investigation revealed that miR-637 expression was inversely correlated with P-REX2a expression in melanoma tissues. P-REX2a was determined to be a direct target of miR-637 by using a luciferase reporter assay. Overexpression of miR-637 decreased P-REX2a expression at both the mRNA and protein levels, and suppression of miR-637 increased P-REX2a expression. Importantly, silencing P-REX2a recapitulated the cellular and molecular effects seen upon miR-637 overexpression, whereas, overexpression of P-REX2a eliminated the effects of miR-637 overexpression on melanoma cells. Furthermore, both enforced expression of miR-637 or silencing of P-REX2a resulted in activation of PTEN, leading to a decline in AKT phosphorylation. Taken together, our study demonstrates that miR-637 inhibites melanoma cell proliferation by activation of AKT signaling pathway and induces apoptosis through regulation of Bcl-2/Bax expression via targeting P-REX2a. These findings suggest that miR-637 plays a crucial role in melanoma progression, and may serve as a potential novel target for melanoma therapy.

Identification and analysis of the reactive metabolites related to the hepatotoxicity of safrole.

1. Safrole is the main component of the volatile oil in Xixin, which has a strong antifungal effect. However, safrole has been shown to be associated with the development of hepatocellular carcinoma. Methylenedioxyphenyl and allyl-benzene substructures of safrole may cause a mechanism-based inhibition (MBI) of CYP450 enzymes (CYPs) and produce reactive metabolites (RMs), resulting in inhibition of enzyme activity and toxic effects. 2. Based on the experiments of CYPs cocktail screening, glutathione (GSH) capture and the IC50 data, we found that safrole had an inhibitory effect on CYP1A2. The test of enzyme activity recovery when adding GSH may help to verify the MBI of safrole. 3. Two metabolites, 1,2-dihydroxy-4-allylbenzene (M1) and 1'-hydroxy safrole (M2) could be captured by GSH. The ultra performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS) method was used to identify the RMs through a detailed characterization of the safrole cleavage processes and the GSH-M1 adduct. The RMs identified are quinone and its tautomer. Thus, preliminary conclusion can be obtained that safrole is a mechanism-based inhibitor of CYP1A2. 4. The cleavage process of the GSH-M1/M2 adduct was analyzed in further detail. We believe the safrole hepatotoxicity mechanism is related to the RMs mediated by CYP1A2. This work provides important information on predicting in vivo drug induced liver injury.

Hydrogen sulfide donor regulates alveolar epithelial cell apoptosis in rats with acute lung injury.

BACKGROUND: Acute lung injury (ALI) is a common syndrome associated with high morbidity and mortality in emergency medicine. Cell apoptosis plays a key role in the pathogenesis of ALI. Hydrogen sulfide (H(2)S) plays a protective role during acute lung injury. We designed this study to examine the role of H(2)S in the lung alveolar epithelial cell apoptosis in rats with ALI. METHODS: Sixty-nine male Sprague Dawley rats were used. ALI was induced by intra-tail vein injection of oleic acid (OA). NaHS solution was injected intraperitonally 30 minutes before OA injection as the NaHS pretreatment group. Single sodium hydrosulfide pretreatment group and control group were designed. Index of quantitative assessment (IQA), wet/dry weight (W/D) ratio and the percentage of polymorphonuclear leukocyte (PMN) cells in the bronchoalveolar lavage fluid (BALF) were determined. H(2)S level in lung tissue was measured by a sensitive sulphur electrode. Apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and Fas protein was measured by immunohistochemical staining. RESULTS: The level of endogenous H(2)S in lung tissue decreased with the development of ALI induced by OA injection. Apoptosis and Fas protein in alveolar epithelial cells increased in the ALI of rats but NaHS lessened apoptosis and Fas protein expression in alveolar epithelial cells of rats with ALI. CONCLUSION: Endogenous H(2)S protects rats from oleic acid-induced ALI, probably by inhibiting cell apoptosis.

[Effect of Gli1 gene silencing on proliferation of K562 cells and its mechanisms].

OBJECTIVE: To investigate the effect of Gli1 gene silencing by RNA interference (RNAi) on proliferation of K562 cells and its mechanisms. METHODS: The small interference RNA (siRNA) was synthesized in vitro. K562 cells were transfected with Gli1 siRNA by the way of lipofection (lipofectamine 2000). Non-specific siRNA transfected cells were used as control. Transfection efficiencies of different siRNA concentrations were detected by flow cytometry and the best siRNA concentration was selected. The silencing effect of siRNA was demonstrated by real time PCR and Westem blot analysis. Cell proliferation was measured by MTT method, cell cycle by PI assay, c-myc and p21 mRNA level was detected by real time PCR analysis. RESULTS: Transfection efficiency of siRNA was increased in a dose-dependent manner when siRNA concentration was below 200 pmol, and the highest transfection efficiency reached (80.11 ± 5.63)%. Both the mRNA and protein level of Gli1 was down-regulated in Gli1 specific siRNA group, the mRNA level was (52.60 ± 3.57)% of that of control group after 24 h (t = 20.33, P < 0.01) and the protein level was (79.31 ± 5.58)% of that of control group after 48 h (t = 6.54, P < 0.01). The cell proliferation rate in Gli1 siRNA group was (94.41 ± 3.58)% (t = 2.40, P = 0.05) and (90.22 ± 3.34)% (t = 4.37, P < 0.01) of that of control group after 24 h and 48 h, respectively. G(2)/M cell cycle arrest was observed, the mRNA level of c-myc was down-regulated while p21 was up-regulated in Gli1 siRNA group after 24 h and 48 h (P < 0.05). CONCLUSIONS: Targeted silencing of Gli1 gene by RNAi inhibits the proliferation of K562 cells, which acts through the down-regulation of c-myc and up-regulation of p21 expression.

[Therapeutic effect of lithium chloride combined with cyclosporine A on mouse model with aplastic anemia].

Wnt signaling has been shown to inhibit adipogenic differentiation while inducing the osteogenic pathway of bone marrow stromal cells (BMSC). Patients with aplastic anemia (AA) often show excess fat accumulation in the bone marrow, possibly due to overactivation of the adipogenic pathway. Therefore, an activator of the Wnt signaling may alleviate the symptoms by enhancing the inhibition on the differentiation of BMSC towards adipocytes. To judge this hypothesis, the therapeutic effects of Wnt signaling activator lithium chloride (LiCl) combined with the currently used immunosuppressor cyclosporine A (CsA) on mice with AA in vivo was investigated. Mouse model with AA was established and the disease was confirmed by increased fat cell counts and decreased hematopoietic cell counts in the bone marrow of these animals. These mice treated with CsA 50 mg/(kg·d) alone or together with LiCl 20 mg/(kg·d), once daily for 5 d, then at day 14, 21 and 28 after establishment of mouse model with AA, the treatment effects were observed, including peripheral blood cells, bone marrow mononuclear cells (BMMNC) count and bone marrow biopsy examination in each group. The results showed that compared with the AA group, Hb content, WBC and BMMNC counts of CsA group and the combination group significantly increased. HE staining of bone marrow biopsy sample showed that the fat cells were significantly reduced in the bone marrow cavity (P < 0.05). Compared with the CsA group, Hb content, WBC and BMMNC counts of the combination group significantly increased (P < 0.05); HE staining of bone marrow biopsy sample showed that fat cells were reduced, the hematopoiesis of bone marrow was close to the normal. It is concluded that Wnt signal activator (LiCl) combined with CsA displayed a better treatment effect on AA in mouse models than the effect of using CsA only. They can promote the hematopoietic function of bone marrow, which may correlate with inhibiting differentiation of bone marrow mesenchymal stem cells into the fat cells by Wnt signaling.

Negative regulation of cyclin D3 expression by transcription factor c-Ets1 in umbilical cord hematopoietic cells.

AIM: To investigate the role of transcription factor c-Ets1 in cyclin D3 expression and its effects on the proliferation of umbilical cord hematopoietic cells. METHODS: Cyclin D3 promoter deletion constructs were generated and transfected into CD34(+) cells. Dual luciferase reporter assays and TFSEARCH software were used to identify negative regulatory domains and to predict putative transcription factors involved in cyclin D3 downregulation. Expression of c-Ets1 in CD34(+) cells was detected using electrophoretic mobility shift and super shift assays. Point mutants of c-Ets1 binding sites were constructed. The wild-type c-Ets1 and the mutant promoter constructs were co-transfected into CD34(+) cells to determine the promoter activity. The impact of c-Ets1 expression on the proliferation of CD34(+) cells was assessed using MTT assay. RESULTS: Nine cyclin D3 promoter deletion constructs were generated. A negative regulatory domain containing c-Ets1 binding sites was identified between -439 bp and -362 bp. Transfection of the promoter deletion constructs containing mutant c-Ets1 binding sites enhanced cyclin D3 promoter activity. However, the opposite results were observed when CD34(+) cells were co-transfected with wildtype c-Ets1 and its promoter deletion constructs. The overexpression of c-Ets1 could suppress cyclin D3 mRNA and protein levels. In addition, it inhibits the proliferation of CD34(+) cells. CONCLUSION: c-Ets1 functions as a negative transcription factor, down-regulating the expression of cyclin D3, which leads to inhibition of CD34(+) cell proliferation.

Protective effect of baicalin against multiple ultraviolet B exposure-mediated injuries in C57BL/6 mouse skin.

Multiple exposures to solar ultraviolet (UV) radiation cause critical damage to skin that may lead to the development of several cutaneous disorders including skin cancer. Protection against sun-induced damage is therefore a highly desirable goal. Chemoprevention via plant-based agents may be a useful approach for the prevention? of UV-induced neoplasia. In this study, we assessed (1) whether baicalin protected against multiple UVB exposure-mediated damage in skin of C57BL/6 mice and (2) the underlying mechanisms. C57BL/6 mice were topically pretreated with baicalin (1 mg/cm(2) skin area/mouse/100 µL acetone) and were exposed to UVB 30 min later (180 mJ/cm(2), on alternate days × 10 exposures). The animals were sacrificed 24 h after the last UVB exposure. Skin edema, histopathology changes, Ki-67, PCNA, and COX-2 were assessed to determine UVB induced damage. Multiple exposures of C57BL/6 mice to UVB resulted in an increase in skin edema and hyperplasia. Topical application of baicalin prior to UVB radiation resulted in a significant inhibition of Ki-67, PCNA and COX-2 expression. These protective effects of baicalin may also inhibit UVB-induced skin carcinogenesis. Based on this data, we suggest that baicalin could be developed as an agent for the management of conditions elicited by multiple UV exposures, including skin cancer.

[Relation of notch pathway to senescence of murine bone marrow stromal cells].

This study was purposed to investigate the relation of the Notch signaling pathway to senescence of murine bone marrow stromal cells in vitro. Intracellular domain of Notch 1 (ICN) was transfected into cultured murine bone marrow stromal cells by lipofectamine transfection. After transfection for three days the proliferation of transfected cells was measured by MTT, cell cycle distribution was analyzed by flow cytometry. The percentage of senescence associated beta-galactosidase (SA-beta-Gal) positive cells were measured by cytochemical method, and the expression rates of P53 and p21Cip1/Waf1 at gene and protein levels were analyzed by RT-PCR and Western blot respectively. The results showed that after transfection for 3 days the proliferation of murine bone marrow stromal cells was inhibited with induction of G1 arrest, the percentage of SA-beta-gal positive cells increased and the p53 and p21Cip1/Waf1 mRNA and protein expression levels were upregulated. It is concluded that the activated Notch signaling can induce premature senescence of bone marrow stromal cells through the p53-p21Cip1/Waf1 pathway.

[Aberrant methylation at promoter region of HOX A gene cluster in leukemia cells].

OBJECTIVE: To explore the characteristics of CpG islands methylation at promoter region of HOX A gene cluster in leukemia cells before and after all-trans retinoic acid (ATRA) treatment. METHODS: Eleven human leukemia cell lines, bone marrow cells from leukemia patients before and after therapy and white blood cells from normal subjects were collected. HL-60 and K562 cells were treated by 2-deoxy-5-azacytidine (DAC) or ATRA respectively. Bisulfite modified DNA of these cells were amplified with PCR and quantitatively analyzed by pyrosequencing for methylation of CpG islands. RESULTS: In normal cells, CpGs at all loci of HOX A cluster were unmethylated. In HOX A4, A6, A7, A9, A10 and A11, many CpG sites were methylated (>20%) or hypermethylated (>50%) in leukemia cell lines. Percentages of methylated CpGs were higher in T-cell leukemia (71.4%) and B-cell leukemia (85.7%) than in others. For individual CpGs methylations there were HOX A4 in all leukemia cells, HOX A6 and HOX A7 in most of the leukemia samples and HOX A10 and HOX A11 in K562 and HL-60 cells (38%-86%). HOX A9 CpGs showed hypomethylation in most of myeloid leukemia cells, whereas HOX A11 CpGs were hypermethylated in B-cell leukemia (>50%). Methylation levels of HOX A4 and A6 in AML and ALL patients after complete remission were decreased obviously, and so did HOX A6 and A9 in CML patients. Methylation levels of HOX A4, A6 and A10 in HL-60 cells and of HOX A6 in K562 cells were reduced by ATRA treatment. CONCLUSIONS: In all leukemia cell lines, aberrant methylation of CpGs was observed at promoter regions of 6 HOX A cluster genes, and some of these genes showed leukemia-type-specific hypermethylation. CpGs methylation of some HOX A genes in leukemia cell lines, especially in HL-60 cells, were down-regulated by ATRA.

[Establishment of a bone marrow failure mouse model by immune injury].

OBJECTIVE: To establish a mouse model for the study of pathophysiologic mechanism and treatment of bone marrow failure (BMF). METHODS: Balb/c mice (recipient) were irradiated 5.0 Gy by gamma rays of (60)Co, and then infused 5 x 10(6) lymph node (LN) cells from DBA/2 mice (donor) in 4 hours. Pancytopenia was monitored by cell counting, bone marrow damage was assessed by histological staining and mononuclear cell counting. Serum IFN-gamma concentration was measured by ELISA. The proportion of Treg in spleen was detected by flow cytometry. RESULTS: Irradiation and infusion of LN cells led to rapid development of severe pancytopenia and BM hypoplasia, which reached the most severity at d14. The pancytopenia remained at d28 and displayed no signs of recovery. The bone marrow was full of adipose cells with scarcity of hematopoietic cells at d14 and persisted at least for 28 days, being similar to the feature of aplastic anemia. Serum IFN-gamma concentration was 6.3 fold increased \[(170.0 +/- 17.0) vs (27.7 +/- 7.1) pg/ml\] at d6. Tregs were decreased after infusion, and then increased \[(3.38 +/- 0.52)%\] and recovered to normal \[(4.04 +/- 0.44)%\] at d21. The expression level of the specific transcription factor Foxp3 was similar to normal. CONCLUSION: The MHC antigen of Balb/c mice is identical to that of DBA/2 mice, but their minor antigen differs. 5.0 Gy irradiation and then 5 x 10(6) lymphocyte infusion can induce BMF similar to the features of aplastic anemia.

[Biological characteristics of hematopoietic progenitor cells at different stages of hematopoietic development].

The aim of the present paper is to better understand the mechanism of hematopoietic development through studying the biological characteristics of hematopoietic progenitor cells at different stages of development. Firstly, the c-kit expression levels of the mononuclear cells from murine embryonic aorta-gonad-mesonephros (AGM) region at embryonic day (E)10.5 and E11.5, fetal liver (FL) at E12.5, E14.5, E16.5, E18 and bone marrow (BM) were assayed with fluorescence activated cell sorting (FACS). Secondly, hematopoietic progenitor cells derived from AGM at E10.5, FL at E14.5 and BM were isolated by using c-kit microbeads. Isolated c-kit(+) population cells from AGM, FL and BM were then co-cultured with E14.5 FL-derived stromal cells in transwell co-culture system in vitro. After 3, 7, 10 days of co-culture, numerous floating cells were generated. The floating cells generated in transwell inserts were collected for FACS cell count, migration activity detection and colony forming unit (CFU) formation assay. The results showed that the c-kit was highly expressed in E10.5 AGM, with the percentage of c-kit(+) cells declining during AGM development. c-kit expression was highly expressed again in E12.5 FL, declining along with the progressive development of the FL region. Co-cultured with FL-derived stromal cells, E10.5 AGM-derived c-kit(+) cells produced the highest number of hematopoietic cells, while BM-derived c-kit(+) cells produced the lowest number of hematopoietic cells. Compared with E10.5 AGM-derived c-kit(+) cells, E14.5 FL- and BM- derived c-kit(+) cells inclined to differentiate after 7 to 10 days of culture in vitro. E10.5 AGM and E14.5 FL-derived c-kit(+) cells exhibited a higher migration activity than BM-derived c-kit(+) cells. Moreover, E10.5 AGM-derived c-kit(+) cells showed a higher ability to form mixed colony-forming unit (CFU-Mix) colony. In conclusion, compared with FL- and BM-derived c-kit(+) cells, E10.5 AGM-derived c-kit(+) hematopoietic progenitor cells exhibit better proliferation, migration potential, and have a higher ability to maintain the undifferentiation state in vitro, providing an insight into their clinical manipulation.

[Diagnostic role of BIOMED-2 multiplex polymerase chain reaction for antigen receptor genes rearrangement in lymphoproliferative disorders].

OBJECTIVE: To establish a sensitive and effective method for detection of immunoglobulin and T-cell receptor (Ig/TCR) gene rearrangement,and to explore its role in diagnosis and differential diagnosis of lymphoproliferative disorders. METHODS: Fifty-eight lymphoid tissue samples from 54 patients with lymphoproliferations were evaluated by the novel BIOMED-2 multiplex polymerase chain reaction (PCR) for antigen receptor genes rearrangement. RESULTS: Multiplex PCR demonstrated monoclonal Ig/TCR gene rearrangements in 22 of 25 (88.0%) B-cell malignancies and 8 of 15 (53.3%) T-cell malignancies. Among 17 benign lymphoproliferations confirmed histopathologically, polyclonal rearrangements were detected in 14 cases (82.4%). In total, the clonality analysis and the final clinico-histopathological diagnosis were concordant in 77.2%. Combination detection of Iglambda and TCR delta gene rearrangements did not increase the detection rate of monoclonal rearrangement of Ig/TCR, but might help to the detection of Iglambda+ or TCR delta+ lymphomas. CONCLUSION: The novel BIOMED-2 multiplex PCR strategy is a rapid, reliable and sensitive approach to detecting clonality in suspected lymphoproliferations, especially in atypical cases.

[In vitro cytotoxic effects of CML28 specific T cells on acute leukemia cells].

OBJECTIVE: To explore the activation and proliferation of specific T cells induced by artificial antigen-presenting cells (aAPCs) simulated dendritic cells (DCs) and to observed the effect of these T cells on leukemic cell killing. METHODS: aAPCs were developed by coating a human leukocyte antigen-immunoglobulin fusion protein ( HLA-lg), which was connected each one of the four CML28 antigen epitopes (DLMSSTKGL, DLMSSTKGL, ALFCGVACA, VLTFALDSV), and CD28-specific antibody, to magnet-beads CML cell specific peptides (CML28) served as target peptides. Bone marrow (BM) or peripheral blood (PB) mononuclear cells (MNCs) were isolated from HLA-A2 healthy volunteers, and co-cultured with aAPCs. Specific T lymphocyte were detected by flow cytometry. The fresh acute leukemic cells were used as target cells. The specific T cells incubated with leukemic cells for 4 h at ratios of 5:1, 10:1, 20:1, 40:1, 80: 1, respectively. The effect of leukemic cells killing was detected by lactate dehydrogenase release test. RESULTS: The average ratio of CML-28 specific T lymphocyte in control group was (2.2 +/- 0.4)% and in experimental groups (DLMSSTKGL, DLMSSTKGL, ALFCGVACA, VLTFALDSV) were (13.5 +/- 1.6)%, (15.2 +/- 1.5)%, (14.7 +/- 1.8)% and (34.3 +/- 3.5)%, respectively, being significantly higher than that in control group (P < 0.01). Induction efficiencies of acute leukemic cells killing were significantly enhanced by increase of effector cells. The cytotoxic activity of specific T lymphocyte in one experimental group (VLTFALDSV) was much higher than that in other three experimental group (P < 0.05). CONCLUSION: This "prime and expand" regimen should be an alternative method for large scale amplification of rare tumor-specific CTLs and aAPCs might be a useful tool for leukemia immunotherapy.