麦胚提取物对辐射损伤修复的实验研究

目的 研究麦胚提取物对小鼠辐射损伤修复的调节和保护作用。方法 采用辐射前或辐射同时饲喂一定量的麦胚提取物，观察小鼠经X射线一次性全身照射后的临床症状、30d存活率、骨髓微核率、外周血白细胞总数在不同时间的变化。结果 与对照组(单纯照射)比较，饲喂麦胚提取物可使小鼠的头面部皮肤、小肠黏膜、肾脏损伤症状得到明显改善；30d存活率为86．17％(P＜0．01)，提高存活率41．79％，保护系数为1．72；骨髓微核率4．62‰；比对照组(12．14‰)降低(P＜0．01)；外周血白细胞总数在7，13，20，30d均显回升(P＜0.05，P＜0．01，P＜0．01，P＜0．01)。结论 麦胚提取物对小鼠辐射损伤修复有一定程度的调节和保护作用，对于辅助肿瘤放射治疗具有重要意义。     

Pathogenesis of Mucocutaneous Lesions in Behçet's Disease

Behcet's disease (BD) is characterized by recurrent oral aphthae, skin lesions, eye lesions, and genital ulceration. To determine the pathogenesis of BD, we performed histological and immunohistochemical studies of these mucocutaneous lesions, an assay of neutrophil activity, and HLA typing. Dense dermal or subcutaneous infiltrations of polymorphonuclear cells (PMN) without leukocytoclastic vasculitis were found in 28 of 57 lesions. Immunohistochemically, deposits of C3 on the vessels were found in 12 of 31 lesions. Deposits of immunoglobulin were not found except for one of IgM. C3 deposits and PMN infiltrations were significantly related (p<0.05). PMN activity by polarization was enhanced; however, the results did not show a significant relationship with the PMN infiltrations or the C3 deposits. The incidence of HLA-B51 was significantly high in BD, but no significant relationship was found between HLA-B51 and the results of other examinations. These results suggest that the pathogenesis of BD lesions differs from that of collagen diseases and that C3 deposits on the vessels may play an important role in the development of mucocutaneous lesions where PMN have mainly infiltrated.     

Secretion and function of the third component of complement (C3) by murine leukocytes.

Our new finding of de novo synthesis and secretion of C3 by both murine peritoneal macrophages and polymorphonuclear leukocytes (PMN) was confirmed by the incorporation of [35S]methionine into C3 molecules and their complete inhibition by cycloheximide. The methods of secretion of C3 from these two types of cells were compared by examining the C3 contents in their culture supernatants. Completely different modes of secretion were observed, i.e. although macrophages synthesize and secrete C3 constitutively, PMN has a mechanism to store the already synthesized C3 in the cell and secrete it in response to stimuli. Protein kinase C (PKC) activators, e.g. 12-O-tetradecanoyl-phorbol 13-acetate, dioctanoyl glycerol, and mezerein, as well as calcium ionophore A23187 stimulate the secretion of C3 from PMN. These results suggest the involvement of PKC and the calmodulin pathway. A very sensitive method for measuring C3 activity was developed which enabled us to show for the first time that C3 secreted by PMN had opsonizing activity and that particles cultured with PMN were phagocytosed effectively.     

Chemoattractant-induced firm adhesion of leukocytes to vascular endothelium in vivo is critically dependent on initial leukocyte rolling

Leukocyte rolling and firm adhesion at the venular endothelium are two discrete events in the cellular inflammatory response mediated via selectin and integrin adhesion molecules, respectively. The dependency of chemoattractant-induced firm leukocyte adhesion on the preceding rolling interaction was investigated in rat mesenteric microvessels through use of intravital microscopy. Leukocyte rolling was dose-dependently inhibited by systemic treatment with the sulphated polysaccharide fucoidin. The firm leukocyte adhesion following stimulation with the chemotactic peptide fMLP was similarly inhibited when fMLP challenge was performed subsequent to inhibition of leukocyte rolling by fucoidin. Thus, based on paired observations in single venules before and after fucoidin treatment, reduced rolling leukocyte flux prior to fMLP challenge was paralleled over a wide range by a proportional decrease in fMLP-induced leukocyte adhesion. The results demonstrate quantitatively a close relationship between the extent of leukocyte rolling and the magnitude of the subsequent firm adhesion response, and, that an initial rolling interaction is a precondition for firm adhesion to occur at physiological blood flow rates in vivo.     

In vitro effects of beetroot juice and chips on oxidative metabolism and apoptosis in neutrophils from obese individuals

Oxidative stress and inflammation are involved in the development of obesity. Beetroot (Beta vulgaris var. rubra) is a food ingredient containing betalain pigments that show antioxidant activity. The in vitro effect of beetroot juice and chips on oxidative metabolism and apoptosis in neutrophils from obese individuals has been investigated. Fifteen obese women (aged 45 +/- 9 years, BMI >30 kg/m2) and nine healthy controls (women, aged 29 +/- 11 years, BMI = 22.2 +/- 1.6 kg/m2) were examined. The investigated products were used as concentrates and after transport and digestion in an artificial gastrointestinal tract. Neutrophil oxidant production, in response to phorbol 12-myristate 13-acetate, was characterized by luminol-dependent chemiluminescence and a flow cytometric dichlorofluorescin oxidation assay. Caspase-3 activity, a marker of apoptosis, was measured by cleavage of the fluorogenic substrate Ac-DEVD-AMC. Neutrophils from obese individuals had a significantly higher ROS production compared with the controls (p < 0.05). Beetroot products inhibited neutrophil oxidative metabolism in a concentration-dependent manner. Also observed were the pro-apoptotic effects of beetroot at a concentration range of 0.1-10% in 24 h culture of stimulated neutrophils. These natural products (in both the liquid and solid state) have antioxidant and antiinflammatory capacity, and could be an important adjunct in the treatment of obesity.     

On the Use of Paramagnetic Beads and Ferrofluids to Assess and Eliminate the Leukocytic Contribution to Oxygen Radical Generation by Human Sperm Suspensions

PROBLEM: To develop a methodology to determine a) the leukocytic contribution to reactive oxygen species generation by human sperm suspensions and b) the therapeutic value of removing these cellular contaminants. METHODS: Leukocytes were removed with paramagnetic beads or colloidal ferrofluids coated with anti-CD45 antibody. The sperm suspensions were monitored for oxidant generation by chemiluminescence, leukocyte contamination by immunocytochemistry, and fertilizing potential using zona-free hamster oocytes. RESULTS: Percoll®-prepared human sperm suspensions exhibited a competence for PMA-induced reactive oxygen species generation which was significantly correlated with leukocyte contamination. However, the purified spermatozoa remaining after paramagnetic bead treatment, also demonstrated an intrinsic capacity for PMA-responsive reactive oxygen species generation and, freed from the oxidative stress created by the leukocytes, exhibited a significantly enhanced capacity for sperm-oocyte fusion. CONCLUSIONS: Although human spermatozoa can generate reactive oxygen species, sperm function is inhibited by the additional oxidative stress created by contaminating leukocytes. Removal of these cells with paramagnetic beads enhances fertilizing potential.     

缺血预处理对犬肺移植供体肺的保护作用

以１０例犬左侧单肺移植为基础，观察左侧肺门阻断１０ｍｉｎ再灌注１５ｍｉｎ的缺血预处理结合４ＣＥｕｒｏ－Ｃｏｌｌｉｎ’ｓ液对供体肺进行冷灌及保存，结果表明：采用肺缺血预处理，对供体肺具有更好的保护作用，其作用机制可能与抑制了中性粒细胞的肺内聚集与激活有关。     

An in vitro study of polymorphonuclear leucocyte-mediated injury to human gingival keratinocytes by periodontopathic bacterial extracts

Human gingival keratinocytes were cultured and, after the first passage, subjected to cell detachment assays with polymorphonuclear leucocytes (PMNs) and/or sonic extracts from Actinobacillus actinomycetemcomitans Y4, and Eikenella corrodens 1073. The effector-to-target cell ratio was 30:1. Bacterial extracts alone caused no disruption of keratinocyte monolayers. PMNs alone also caused only minimal detachment after 14 h incubation. Adding A. actinomycetemcomitans to the PMN-keratinocyte co-cultures at the concentration of 100 μg/ml caused dramatic cell detachment. The effect of A. actinomycetemcomitans was heat labile and not inhibited by polymyxin B. Cell detachment was inhibited by α₁-antitrypsin, whereas catalase and Superoxide dismutase could not prevent it. No lysis of keratinocytes was observed after incubation, as judged by ⁵¹Cr release. E. corrodens had little effect even at the concentration of 1000 μg/ml. H₂O₂ and partially purified PMN elastase also caused detachment of keratinocytes. These data indicate that PMNs can cause non-lytic detachment of keratinocytes when interacting with certain bacteria.