三种阳离子脂质体介导血管内皮细胞基因转染效率的比较

目的:评价不同阳离子脂质体介导基因转染血管内皮细胞的转染效率。方法:实验于2006-12/2007-02在中山大学生化实验室及广州市创伤外科研究所完成。采用增强型绿色荧光蛋白基因为报告基因,分别采用Lipofectin、Lipofectamine、Dosper3种不同的阳离子脂质体为载体,转染人脐静脉血管内皮细胞。在24孔板中,每孔加入人脐静脉血管内皮细胞悬液(1×106个细胞),各孔分别加入3种不同阳离子脂质体增强型绿色荧光蛋白质粒复合物,分别于培养24,48h后用荧光显微镜及流式细胞仪测定增强型绿色荧光蛋白在细胞内的表达及转染效率。结果:3种不同阳离子介导的增强型绿色荧光蛋白基因转染的人脐静脉血管内皮细胞内均有绿色荧光蛋白表达,24h后明显,48h后达高峰。Dosper介导组绿色荧光细胞百分比明显高于Lipofectin介导组及Lipofectamine介导组,差异有非常显著意义(P<0.01)。结论:Dosper介导的血管内皮细胞基因转染效率较高,较适合作为血管内皮细胞的基因转染载体。     

Multiple unconfirmed-reactive screening tests for viral antibodies among blood donors

BACKGROUND: In December 1991, the United States Food and Drug Administration received reports of blood donations with unconfirmed reactivity on screening tests for antibodies to human immunodeficiency virus, human T-lymphotropic virus type I, and hepatitis C virus (HCV). Of 91 donors with these test results, 57 (63%) reported a recent influenza vaccination. STUDY DESIGN AND METHODS: To determine the extent of unconfirmed reactivity, the time at which it began, and its association or nonassociation with specific manufacturers' tests, a nationwide survey of blood centers was conducted. A case-donation was defined as a blood donation that was repeatedly reactive, but not confirmed positive, on at least two of the three tests from May 1990 through December 1991. RESULTS: Among 14 million donations screened by 110 centers, 582 case-donations were identified. An increase in case- donations was evident in the fall of 1990 (2.8/100,000 donations). In 1991, rates increased from 0.9 per 100,000 donations in the first quarter to 1.3, 3.2, and 19.7 in subsequent quarters. A significantly higher rate of case-donations was observed among donations tested with one of the two available anti-HCV screening tests (8.0 vs. 1.2/100,000 donations; risk ratio = 6.8; 95% CI = 5.4-8.5). CONCLUSION: Although unconfirmed reactivity on multiple screening tests appeared to be seasonal, its documentation prior to the availability of influenza vaccine in 1991 and higher rates among donations tested with one manufacturer's anti-HCV test indicated that test-specific factors were also involved.     

成人骨髓间充质干细胞的体外培养及生物学特性

目的:观察成人骨髓间充质干细胞体外分离培养方法及其生物学特性,为骨髓间充质干细胞的临床应用奠定技术基础。方法:实验于2005-12在吉林省四平市中心医院中心实验室进行。实验材料:人骨髓间充质干细胞,Ficoll淋巴细胞分离液,胎牛血清,牛血清白蛋白,α-MEM培养基,胰蛋白酶,FITC标记的CD44和CD90。实验方法:①人骨髓间充质干细胞的分离与培养:采集成人骨髓,密度梯度法分离单个核细胞,条件培养基培养和扩增,倒置光学显微镜下观察细胞形态及生长情况。②人骨髓间充质干细胞生长曲线的测定:取生长良好的P1,P5,P10细胞,用胰酶消化,接种于24孔板培养,每天各取3孔消化计数细胞,取平均值,连续培养7d,绘制生长曲线。③人骨髓间充质干细胞表面标志的测定:取生长良好P5细胞进行免疫荧光染色鉴定(CD44,CD90并设同型对照)。④人骨髓间充质干细胞的冻存及复苏:收集生长良好细胞,计数细胞密度及冻前存活率。将细胞加入到细胞冻存液中液氮冷冻保存。30d后复苏细胞,每日倒置光学显微镜下观察细胞生长状况。结果:①倒置显微镜下观察细胞形态:倒置显微镜下观察细胞呈纤维形,漩涡状生长。②人骨髓间充质干细胞的生长曲线分析:传代的细胞生长较原代要快,从第10代开始细胞生长开始出现缓慢征象。③细胞表面标记检测结果:免疫荧光染色后细胞膜着色明显,CD44,CD90阳性率均大于90%。④细胞冻存及复苏生长特性分析:椎虫蓝计数细胞存活率90%以上,增殖能力强,和未冻存过的传代细胞具有同样的生长特性。结论:应用密度梯度法分离法能获得较高纯度的骨髓间充质干细胞,能在体外长期培养,在传代培养5代内生长旺盛且生物学特性稳定。     

Purging murine leukemic marrow with alkyl-lysophospholipids

Autologous bone marrow transplantation is potentially curative in the treatment of acute leukemia if residual leukemic cells in the marrow can be eliminated prior to transplantation. We studied the purging effects of a synthetic alkyl-lysophospholipid (ALP) on marrow containing leukemic cells from a transplantable myelomonocytic leukemia (WEHI-3B) in BALB/c mice. Simulated remission bone marrow containing 2% leukemic cells treated in vitro with 20 and 100 micrograms/mL of ET-18- OCH3 (1-octadecyl-2-methyl-sn-glycerol-3-phosphocholine) significantly prolonged survival of lethally irradiated transplanted recipients. At a dose of 100 micrograms/mL, 88% of the mice survived for the duration of the experiment (approximately five months). Autopsies showed that 25% of these survivors had microscopic evidence of leukemia. Thus, in vitro treatment of marrow eliminated leukemic blasts and spared sufficient normal stem cells to allow hematologic reconstitution. The effect of ET- 18-OCH3 is not entirely selective for leukemic cells. A spleen colony assay showed that ALP has some cytotoxic effect on normal hematopoietic stem cells.     

Extruded erythroblast nuclei are bound and phagocytosed by a novel macrophage receptor

Resident bone marrow macrophages (RBMM) play an important role in clearance of nuclei extruded from late-stage erythroblasts (Eb). To investigate the nature of macrophage receptors involved in this process, extruded erythroblast nuclei (EEN) were purified by cultivation of erythroblasts with erythropoietin, followed by density gradient centrifugation. By electron microscopy, the majority of free nuclei had an intact plasma membrane. EEN bound avidly to RBMM in a divalent cation-independent manner at both 4 degrees C and 37 degrees C. The use of specific monoclonal antibodies (MoAbs) and inhibitors showed that this adhesive interaction was not mediated by previously characterized macrophage receptors involved in recognition of either developing hematopoietic cells or apoptotic cells. The EEN receptor was expressed on resident macrophages isolated from murine bone marrow, spleen, lymph node, and peritoneal cavity, but was completely absent from alveolar macrophages. Despite high levels of EEN binding to RBMM, few were phagocytosed even after prolonged culture. Phorbol myristate acetate (PMA) was found to stimulate phagocytosis, suggesting that this is a regulated process. These findings indicate that EEN are recognized by a novel macrophage receptor and that recognition may be triggered during the membrane remodeling that accompanies enucleation.     

Combination therapy for radiation-induced bone marrow aplasia in nonhuman primates using synthokine SC-55494 and recombinant human granulocyte colony-stimulating factor

Combination cytokine therapy continues to be evaluated in an effort to stimulate multilineage hematopoietic reconstitution after bone marrow myelosuppression. This study evaluated the efficacy of combination therapy with the synthetic interleukin-3 receptor agonist, Synthokine- SC55494, and recombinant methionyl human granulocyte colony-stimulating factor (rhG-CSF) on platelet and neutrophil recovery in nonhuman primates exposed to total body 700 cGy 60Co gamma radiation. After irradiation on day (d) 0, cohorts of animals subcutaneously received single-agent protocols of either human serum albumin (HSA; every day [QD], 15 micrograms/kg/d, n = 10), Synthokine (twice daily [BID], 100, micrograms/kg/d, n = 15), rhG-CSF (QD, 10 micrograms/kg/d, n = 5), or a combination of Synthokine and rhG-CSF (BID, 100 and 10 micrograms/kg/d, respectively, n = 5) for 23 days beginning on d1. Complete blood counts were monitored for 60 days postirradiation and the durations of neutropenia (absolute neutrophil count < 500/microL) and thrombocytopenia (platelet count < 20,000/microL) were assessed. Animals were provided clinical support in the form of antibiotics, fresh irradiated whole blood, and fluids. All cytokine protocols significantly (P < .05) reduced the duration thrombocytopenia versus the HSA-treated animals. Only the combination protocol of Synthokine + rhG-CSF and rhG-CSF alone significantly shortened the period neutropenia (P < .05). The combined Synthokine/rhG-CSF protocol significantly improved platelet nadir versus Synthokine alone and HSA controls and neutrophil nadir versus rhG-CSF alone and HSA controls. All cytokine protocols decreased the time to recovery to preirradiation neutrophil and platelet values. The Synthokine/rhG-CSF protocol also reduced the transfusion requirements per treatment group to 0 among 5 animals as compared with 2 among 5 animals for Synthokine alone, 8 among 5 animals for rhG-CSF, and 17 among 10 animals for HSA. These data showed that the combination of Synthokine, SC-55494, and rhG-CSF further decreased the cytopenic periods and nadirs for both platelets and neutrophils relative to Synthokine and rhG-CSF monotherapy and suggest that this combination therapy would be effective against both neutropenia and thrombocytopenia consequent to drug- or radiation- induced myelosuppression.     

p15ink4B and p16ink4 gene inactivation in acute lymphocytic leukemia

Malignant cells from 52 children with acute lymphocytic leukemia (ALL) were investigated for inactivation of the p15ink4B and p16ink4 genes and other genetic alterations on chromosome 9p21. Homozygous deletions of the p15ink4B and/or the p16ink4 genes were detected in 16 cases and a further 9 cases showed evidence of allelic loss either by hemizygous deletion or loss of heterozygosity (LOH) for 9p21 markers. Most cases had loss of both genes, but 5 patients had lost only p16ink4 and 2 cases had homozygous loss of p15ink4B only. Sequence analysis of all exons of p15ink4B and p16ink4 was performed in patients with hemizygous deletions or LOH for 9p21 markers. A frame shift mutation of p16ink4 exon 1 was shown in 1 case, whereas all other clones carried the wild- type sequence of p15ink4B and p16ink4 in the remaining allele. The data suggest that both the p15ink4B and p16ink4 genes can be inactivated in ALL. The existence of a hitherto undefined tumor-suppressor gene on chromosome 9p cannot be ruled out.     

Effect of age and sex on left atrial morphology and function.

AIMS: Left atrial function is abnormal in a wide range of cardiac diseases. This study was designed to assess the effects of normal ageing and sex on left atrial morphology and function. METHODS AND RESULTS: Echocardiography was performed in 123 subjects (age 57 +/- 19 years, range 22 to 89 years, 59 women) with no evidence of cardiovascular disease. M-mode derived left atrial size, B-mode derived left atrial maximal and minimal volumes, and the volume at onset of atrial systole (P-volume) were measured. Left atrial filling, active and passive emptying volumes and ejections fractions, and expansion index were calculated. Subjects were divided into four groups according to age. Left atrial diameter increased with age, with significantly smaller left atrial size in younger subjects. The oldest subjects had significantly higher (P<0.05) left atrial minimal, maximal and P-volume indices. Filling volume index was highest in the oldest subjects (21.9 +/- 5.6 ml/m(2)). Passive emptying volume index was the lowest in those of middle age (10.5 +/- 2.8 ml/m(2)). Active emptying volume index progressively increased with age (P<0.001). Left atrial expansion index and active emptying fraction were not different between the age groups. There was significant difference in passive emptying fraction (P<0.001) with highest values in the youngest (44.7 +/- 7.3%) and lowest values in the oldest subjects (33.6+/-5.4%). CONCLUSIONS: Age- and sex-related reference values of echocardiographic indices of left atrial morphology and function are reported. Ageing is associated with left atrial dilatation. Left atrial conduit function deteriorates with age while reservoir and pump function are maintained. Left atrial anteroposterior diameter is smaller in women than in men, but overall left atrial function is not influenced by sex.     

Hemoglobin M equon beta 41 (C7) phenylalanine leads to tyrosine

A severe hemolytic crisis was observed in a 34-yr-old female of English- Irish extraction following a viral illness treated with acetaminophen. Heinz bodies and heat instability were present only during a transient hemolytic event. A challenge dose of acetaminophen caused no detectable hematologic abnormality. Structural studies of the hemoglobin during hemolysis and again after complete recovery localized the abnormality to tryptic peptide beta Tp-5, and automated sequencing of I 125-labeled beta chains indicated a replacement of phenylalanine (C7) beta 41 by tyrosine. Substitution of the next residue, phenylalanine (CD1) beta 42 by serine (Hb Hammersmith), has resulted in chronic severe Heinz body hemolytic anemia. The lack of chronic anemia in the present disorder may reflect the different relationships of beta41 and beta 42 and/or the similarities in volume and hydrophobicity of tyrosine and phenylalanine. It is suggested that substitution of tyrosine for phenylalanine in Hb Mequon may disturb the critical environment around the heme group and render it susceptible to oxidative denaturation in the presence of infections and/or drugs.     

The prevalence of heart failure and asymptomatic left ventricular systolic dysfunction in a typical regional pacemaker population.

AIMS: To assess the prevalence of heart failure and asymptomatic left ventricular systolic dysfunction in the chronically paced population. METHODS AND RESULTS: Three hundred and seven patients were identified from attendance at routine pacemaker follow-up clinic. Subjects underwent a medical history and examination, 6-minute walk test and echocardiography. 94 (31%) had a left ventricular ejection fraction (LVEF) <40%, of whom 83 had symptoms of heart failure (70% NYHA II, 26% NYHA III and 4% NYHA IV). Heart failure was more prevalent in patients with single chamber compared to dual chamber pacemakers, (DDD(R) 18% vs 35% VVI(R), p<0.008), and those with chronic atrial fibrillation (AF) compared to those with sinus rhythm (42% vs 21%, p=0.003). Decreasing 6-minute walk distance, history of ischaemic heart disease and years of pacing were independently associated with the presence of heart failure (combined R=0.572, p<0.001). CONCLUSIONS: Heart failure due to left ventricular systolic dysfunction is common in the paced population. Only a minority of these had a pre-existing diagnosis and a smaller proportion were on 'optimal' therapy. Echocardiographic screening of this high-risk population is justified to improve rates of diagnosis and treatment of heart failure.