A delay in bone marrow transplantation after partial conditioning improves engraftment

BACKGROUND: In the present study we examined the effect of the timing of marrow infusion on engraftment in nonmyeloablatively conditioned mice. METHODS: B10 mice were conditioned with decreasing doses of total body irradiation (TBI) and reconstituted with bone marrow cells (BMCs) from major histocompatibility complex-disparate donor B10.BR mice at 0 or 6 hr, or on days 1, 2, 3, 4, 5, 8, and 12 with respect to TBI. RESULTS: After undergoing conditioning with 700 cGy TBI and transplantation with 15 x 10(6) BMCs, 100% of recipients engrafted if the marrow was infused between 0 and 4 days after TBI. For lower doses of TBI, a delay in infusion of the marrow after TBI conditioning was associated with a significant increase in engraftment. Significantly less engraftment was achieved in animals conditioned with 600 cGy TBI if the marrow was infused at 0 or 6 hr compared with a 1- to 4-day delay. When the TBI was decreased to 500 cGy, engraftment occurred only when the transplant was performed between days 2 and 8. The highest proportion of recipients engrafted when the marrow was infused on day 4. This enhanced engraftment after a delay in marrow infusion is associated with a significant reduction in host mixed lymphocyte reaction reactivity and is correlated inversely with serum levels of interleukin-6 in the recipient. CONCLUSIONS: These data demonstrate for the first time that a delay between conditioning and marrow infusion significantly improves allogeneic engraftment in nonmyeloablatively conditioned recipients and reduces the total conditioning required.     

Expression of a fibrinogen fusion peptide in Escherichia coli: a model thrombin substrate for structure/function analysis

The initial event in fibrin clot formation is the thrombin-catalyzed cleavage of the A alpha chain of human fibrinogen. Most of the information required for thrombin recognition and cleavage of the A alpha chain lies in the amino terminal 51 residue CNBr fragment. By selective modification of residues in this region, we probed the features that participate in thrombin interactions. We constructed a vector which expressed a tripartite protein (tribrid) consisting of amino acids 1 to 50 of the A alpha chain followed by 60 amino acids of chicken collagen and the beta-galactosidase protein from Escherichia coli. Cell lysates run on NaDodSO4-polyacrylamide gels contained the predicted band of molecular weight (mol wt) 125,000. The tribrid reacted with a monoclonal antibody, Mab-Y18, which recognizes the amino terminus of the A alpha chain. When cell lysates were incubated with thrombin, FPA was released. By including one heterogeneous oligonucleotide in the construction, we generated plasmids that encoded three specific amino acid substitutions. Surprisingly, changing Gly14 to Val did not alter thrombin cleavage, although recognition by Mab-Y18 was lost. Substitution of lie for Arg23 did not alter either thrombin cleavage or monoclonal recognition. Substitution of Leu for Arg 16 altered thrombin cleavage; unexpectedly, recognition by Mab-Y18 was not changed.     

Squamous cell carcinoma of the head and neck at the Massachusetts General Hospital: a comparison of biologic characteristics in men and women

Little is known about the biologic behavior of squamous cell carcinoma of the head and neck in women. A few recent reports for selected sites have suggested that these tumors may be becoming more common in women. To evaluate potential differences between males and females with squamous cell carcinoma of the oral cavity, oropharynx, and hypopharynx and to assess whether the proportion of females with this disease is increasing, the authors have undertaken a retrospective review of 542 consecutive patients treated at our institution from 1962 through 1976. We report here the first detailed comparison of males and females with squamous cell carcinoma of the head and neck, with attention directed to stage at initial presentation, choice of therapy, response to therapy, age distribution, survival, and prevalence of second primary malignancies. It has been widely published that survival for women with squamous cell carcinoma of the head and neck is superior to that for men, and this has been attributed to a difference in the biologic characteristics of the disease between the two sexes. Although overall survival calculations in our series suggested a significantly better survival rate for women than for men, these rates were strongly influenced by the larger proportion of women (64%) who had stage I or II disease, compared with only 50% of men. When survival was compared stage by stage, there was no significant difference in survival between the two sexes. The proportion of females in the combined study population was 35%, increasing from 33% in the first 5 years of the study period to 40% in the last 5 years. Among patients born before 1920, 34% were female compared with 43% of patients born after 1920. Of the 13 patients less than 40 years of age at diagnosis, 62% were female. The rising proportion of women during the 15-year study period, particularly among young patients and those in more recent birth cohorts, strongly suggests that squamous cell carcinoma of the head and neck is increasing among women in this referral population. A review of the literature indicates that this trend began more than 40 years ago.     

大鼠脂肪间充质干细胞的成骨分化

目的:观察大鼠脂肪间充质干细胞经成骨诱导向成骨细胞分化的生物学特性,探讨其作为骨组织工程种子细胞的可行性。方法:实验于2004-07/2006-03在中南大学湘雅医院中心实验室完成主要工作。①取健康SD大鼠双侧腹股沟区脂肪垫,消化法分离出脂肪间充质干细胞,接种入含有体积分数为0.1的新生牛血清的低糖DMEM培养基进行原代培养。②取第3代的脂肪间充质干细胞,用含有体积分数为0.1的新生牛血清、0.1μmol/L地塞米松、50μmol/L抗坏血酸、10mmol/Lβ-甘油磷酸钠的高糖DMEM培养基诱导其向成骨细胞分化。③于3,5,7,10,12,14,21d分别采用倒置显微镜观察细胞形态及增殖情况、Gomori改良钙钴法碱性磷酸酶染色、茜素红S钙结节染色和Ⅰ型胶原免疫细胞化学染色检测脂肪间充质干细胞成骨分化的情况。结果:①脂肪间充质干细胞原代细胞呈成纤维细胞样长梭形外观,传代稳定,细胞形态均一。②经成骨诱导,脂肪间充质干细胞体积增大,呈多角形;成骨诱导14d,Gomori改良钙钴法碱性磷酸酶染色,细胞胞浆内可见浅棕色至棕黑色的颗粒,平均染色阳性率为80%;碱性磷酸酶活性随时间的延长而逐渐增高[3,5,7,10,12,14d依次为(2.43±0.09),(3.60±0.08),(5.01±0.09),(7.75±0.07),(9.59±0.09),(10.94±0.10)μkat/L];成骨诱导21d,钙结节形成明显,茜素红S染色,呈红色结节;成骨诱导7d,Ⅰ型胶原免疫细胞化学染色,细胞胞浆呈棕黄色,胞核经苏木精复染为蓝色。结论:大鼠脂肪间充质干细胞经成骨诱导具有成骨细胞的生物学特性,可作为骨组织工程的种子细胞。     

Survey on pretransfusion testing

BACKGROUND: Hospitals and blood centers throughout the United States use a variety of reagents and methods to perform pretransfusion testing. A survey was developed to determine the reagents and methods in use and their relative prevalence in different work settings. STUDY DESIGN AND METHODS: A national survey on pretransfusion testing was conducted. Surveys were distributed to state and regional blood bank associations, which then distributed them to hospitals and blood centers within their region. In most instances, the blood centers distributed the survey to the local hospitals. Completed surveys were returned to the authors for review, and all information was entered into a database for analysis. RESULTS: Analysis of the data shows that the majority of blood banks use monoclonal reagents for ABO testing and monoclonal-polyclonal blended reagents for Rh testing. The data show that anti-IgG and polyclonal antihuman globulin reagents are used almost equally for antibody screening (detection) tests and that most blood banks use a three-cell antibody-screening test. Slightly more than 50 percent of hospitals use an immediate-spin crossmatch in the absence of unexpected antibodies. CONCLUSION: A number of approved reagents and methods are used by blood bank laboratories for pretransfusion testing. Facility size (number of beds) and type tend to influence the choice of methods and reagents employed. This survey provides an opportunity for blood bank laboratories to compare their current practices with those of their peers.     

Prolonged procoagulant activity on overstretch-injured coronary arteries in pigs

Summary.  This study was designed to assess the time course and nature of the vascular procoagulant response after 1.5-fold balloon overstretch injury of the coronary arteries in pigs. Arteries were excised for chromogenic assay of bound factor (F)Xa and thrombin at 24 h, 3 days, 1 week, or 2 weeks after injury. FXa at the site of injury remained elevated for 1 week (4.9 ± 5.9 µg cm⁻², n  = 10), compared with non-injured control arteries (0.4 ± 0.2 µg cm⁻², n  = 18, P  = 0.00025), while thrombin was increased only at 24 h. Tissue factor protein was abundant in non-injured coronaries (10 ± 6 ng µg⁻¹ total protein, n  = 9) and levels were unchanged by injury (13 ± 11 ng µg⁻¹, n  = 6) or 24-h administration of tissue factor pathway inhibitor (16 ± 6 ng µg⁻¹, n  = 6). Persistent tissue factor-mediated procoagulant activity may explain the need for prolonged anticoagulation to attenuate neointimal formation after balloon-induced coronary injury.