A model for the formation and lysis of blood clots

Both biochemical and mechanical factors have to be taken into account if a meaningful model for the formation, growth, and lysis of clots in flowing blood is to be developed. Most models that are currently in use neglect one or the other of these factors. We have previously reported a model [J Theoret Med 2003;5:183-218] that we believe is a step in this direction, incorporating many of the crucial biochemical and rheological factors that play a role in the formation, growth, and lysis of clots. While this model takes into account the extrinsic pathway of coagulation, it largely ignores the intrinsic pathway. Here, we discuss some of the general issues with respect to mathematical modeling of thrombus formation and lysis, as well as specific aspects of the model that we have developed.     

An apparatus for measuring the tensile strength of blood clots

An apparatus is described which uses the principle of the ballistic pendulum to measure the tensile strength of blood clots formed in special cuvettes. The method appears to have a reproducibility which would allow a study to be made of the factors influencing clot strength. A brief survey of the findings with normal blood and with blood from cases of thrombosis and haemophilia shows significant differences between the mean values for each group.     

CT静脉造影术可增加对静脉血栓风险的发现

放射医学杂志于2月份发表的一项研究指出,对下肢进行计算机成像技术(CT)扫描可预防肺部复发性血栓的发生.该研究发现间接CT静脉造影(CTV)可证实是否存在潜在脱落风险的下肢血栓,后者可随着血流到达肺动脉血管,形成至命的肺栓塞.肺栓塞和下肢血栓形成(也称深部静脉血栓形成),均是以血栓栓塞为主要表现的疾病.CT肺血管造影(CTPA)是肺部扫描的技术之一,常常用于检测肺部是否存在血栓.由于许多小血管中的血栓不能被该检查发现,因此有些病人的血栓性疾病并不能得到诊断.间接CTV可能有助于发现这类血栓形成.“许多研究显示仅治疗与复发性肺…     

Pneumonia following experimental bronchial obstruction in sheep

Five of 7 sheep in which the bronchi supplying the right apical lobe of the lung were obstructed with a cottonwool plug developed pneumonia. Large numbers of bacteria were isolated from 4 of the 5 pneumonic lungs. Only minor pulmonary lesions, which are common in sheep on pasture, were observed in 5 sham operation and 5 control sheep. These results support a role for airway obstruction in compromising the antimicrobial defences of the lungs in naturally occurring bacterial pneumonias of sheep.     

Evidence for a continuing accumulation of APSAC (Anisoylated plasminogen streptokinase activator complex) by human clots: Comparison with the binding of other plasminogen activators and Plasminogen

The uptake of [¹²⁵I-plasminogen]-APSAC into crosslinked human plasma clots from autologous plasma was significantly greater than the uptake of equimolar iodinated lys77-plasminogen. The uptake of APSAC in the presence of 6-aminohexanoic acid (10 mM) was also significantly greater than the uptake of plasminogen in the presence of 6-aminohexanoic acid.The accumulation of APSAC continued for at least 2 h (in nonlysing conditions), was similar in platelet-rich, platelet-poor and whole-blood clots and was not affected by prior aging of the clots (up to 6 h). The uptakes of APSAC and streptokinase plasminogen were slightly affected by the plasma concentration of anti-SK IgG and, in general, the fibrin-binding of APSAC was similar to the binding of radiolabelled t-PA. Urokinase (high-molecular weight) did not demonstrate fibrin- binding, the uptake being explained by simple diffusion (quantified using albumin). The relative order of continuing accumulation APSAC = t-PA > lys-plasminogen > urokinase is similar to the order of initial binding (< 1 min incubation), and we conclude that the formation of an acylated, stabilised, activator complex of lys-plasminogen and streptokinase imparts additional fibrin-binding to lys-plasminogen.     

Comparison of fibrin clots derived from peripheral blood and bone marrow

Background: Autologous fibrin clots derived from peripheral blood (pb-fibrin clot) and bone marrow (bm-fibrin clot) are thought to be effective for tissue regeneration. However, there is no report detailing the amount of growth factors in pb-/bm-fibrin clot. In this study we evaluated the amount of growth factors in human pb-/bm-fibrin clot, and prove the validity of fibrin clot for clinical use. Methods: Human pb-/bm-fibrin clots were obtained during surgery. In the first experiment, enzyme-linked immunosorbent assay (ELISA) was performed for detecting the amount of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), insulin-like growth factor-1 (IGF-1), fibroblast growth factor basic (bFGF), hepatocyte growth factor (HGF), transforming growth factor-beta (TGF-β), platelet derived-growth factors-AB (PDGF-AB), and stromal cell-derived factor-1 (SDF-1). In the second experiment, the efficacy of fibrin clot on the osteogenic differentiation and fibroblast proliferation was evaluated. Pb-/bm-fibrin clots were incubated in human osteoblast derived from mesenchymal stromal cells (MSCs) or human skin fibroblast. Alizarin red staining and real-time PCR (COL1A1, RUNX2) were performed for the detection of osteogenic potential. Cell-growth assay (WST-8) and real-time PCR (COL1A1) were also performed for the detection of the potential of fibroblast proliferation. Results: ELISA analysis revealed that the amount of VEGF, HGF, bFGF, IGF-1, and SDF-1 of bm-fibrin clot group is higher than that of pb-fibrin clot group with statistical differences. Besides, we confirmed that bm-fibrin clot has much potential for the osteogenic differentiation and fibroblast proliferation. Conclusion: The positive outcomes confirm the efficacy of pb-/bm-fibrin clot, and bm-fibrin clot was proved to have much potential for tissue regeneration compared with pb-fibrin clot. The current study showed the potential of a strategy for regenerative medicine using bm-fibrin clot.     

Pathogenesis of bronchial obstruction under conditions of disturbed adrenoception

Experimental disturbances in β-adrenoception cause non-specific changes in the development of bronchial obstruction in response to humoral and neural bronchoconstrictor stimuli, which are manifested in bronchial smooth muscle hyperreactivity. The bronchospastic reaction develops more rapidly, persists for a longer time, and is always accompanied by early activation of non-smooth muscle pathogenetic mechanisms. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 3, pp. 275–277, March, 1999     

Prevention of allergen-induced bronchial obstruction in sensitized guinea pigs by crude alcoholic onion extract

Thirteen guinea pigs, sensitized to ovalbumin, were pretreated with either 1 ml alcoholic onion extract (=12% v/v ethanol) or 1 ml 12% ethanol solution (control) according to a randomized crossover protocol. Thirty minutes later the animals were challenged twice for 30 sec (n=5), respectively 60 sec (n=8), by the inhalation of ovalbumin (1 ml 1% ovalbumin solution nebulized in 10 l air). The intensity of bronchial obstruction was measured by whole body plethysmography using as parameter the amount of compressed air. Oral pretreatment of guinea pigs with onion extract markedly reduced the asthmatic response (p<0.02). After onion pretreatment near normal values were obtained after 30 sec challenge (0.04±0.06 ml compared to 0.24±0.15 ml in the control) and only slightly increased values after 60 sec challenge (0.16±0.07 ml compared to 0.33±0.25 ml in the control).     

Endobronchial metastatic breast cancer with pagetoid histology mimicking bronchial pagetoid squamous cell carcinoma in situ

We report a case of a 56-year-old woman with endobronchial breast cancer metastasis of unusual histology. The patient presented with persistent cough, and a lesion was noted in the left mainstem bronchus on bronchoscopic examination. Biopsy revealed extensive squamous metaplasia of bronchial epithelium along with large, atypical cells exhibiting pagetoid intraepithelial spread within squamous mucosa. Immunohistochemical stains were compatible with a diagnosis of metastatic breast adenocarcinoma with pagetoid spread. To our knowledge, this is the first reported case of endobronchial breast cancer metastasis with this histologic presentation. In this report, we describe the clinical, radiographic, bronchoscopic, histologic, and immunohistochemical characteristics of this case. We provide a brief review of existing literature on endobronchial breast cancer metastasis. In addition, we discuss the principal differential diagnosis of bronchial pagetoid lesions. This report raises awareness of this uncommon manifestation of metastatic breast cancer.