Human IgG anti-F(ab'')2 antibodies possess rheumatoid factor activity.

Individual preparations of affinity purified anti-F(ab')2 antibodies and anti-Fc antibodies isolated from the sera of patients with rheumatoid arthritis (RA), were examined for reactivity with the Fab and Fc fragments of human IgG. Western blot assays demonstrated specific interaction of affinity-purified anti-Fab antibodies with both Fab and Fc molecules. Approximately one-half of the anti-Fab antibody preparations studied contained IgG antibodies reactive with Fab and Fc fragments in ELISA, suggesting the existence of naturally occurring epibody-like autoantibodies in these patients. Thirteen of 14 affinity-purified anti-Fc antibody preparations contained IgG cross-reactive with Fab molecules in ELISA. Double-adsorption assays on affinity columns demonstrated that a minimum of 14%, and possibly as much as 50%, of the IgG anti-Fab antibodies reacted with the Fc of IgG. Conversely, a minimum of 12%, and possibly as much as 70%, of the IgG anti-Fc antibodies reacted with IgG Fab molecules. Anti-Fab antibodies isolated from non-RA individuals also exhibited anti-Fc reactivity in ELISA, demonstrating the presence of these dual-reactive antibodies in other autoimmune and normal individuals. These studies establish the presence of naturally occurring IgG autoantibodies reactive with both the Fab and Fc fragments of human IgG. Their existence emphasizes the potential of anti-immunoglobulin antibodies to recognize a multiplicity of antigens, possibly including other members of the immunoglobulin supergene family.     

Neuropeptides TRH and cyclo(His-Pro) share neuromodulatory,but not stimulatory,action on hypothalamic neurons in vitro: implication for the regulation of feeding

Summary Electrical activity of neurons in rat hypothalamic ventromedial nucleus was recorded in tissue slices, to investigate central neural mechanisms underlying reduction of food intake caused by TRH and its metabolite, cyclo(His-Pro) [cHP]. Application of TRH had two actions: stimulation of neuronal activity, which was desensitized on closely repeated applications; and modulation of neuronal responses to neurotransmitters, even in the absence of the stimulatory action. The neuromodulatory but not the direct stimulatory action could also be achieved by cHP. The neuromodulatory action is more likely to be a neural mechanism underlying the inhibition of feeding, while other biological functions, unique to TRH, may depend on direct stimulation. In this way, TRH could achieve different biological results through different modes of action on hypothalamic neurons.     

Effects of SITS on urate transport by isolated,perfused snake renal tubules

Effects of an inhibitor of membrane anion-exchange transport processes, 4-acetamido-4-isothiocyano-2,2-disulfonic stilbene (SITS), on urate transport by isolated, perfused snake (Thamnophis spp.) proximal renal tubules were studied. SITS (10^–4 mol/l) in the luminal perfusate had absolutely no effect on net urate secretion (J _urate ^net ) or on net fluid absorption (J _v). This observation is compatible with other data that give no support to the concept of a mediated transport step for urate from the cells to the lumen. SITS (10^–4 mol/l) in the bathing medium reversibly inhibitedJ _urate ^net without affectingJ _v. At the time of maximum inhibition ofJ _urate ^net , the concentration of urate in the cell water was increased and the apparent permeability of the luminal membrane to urate was decreased, but the urate efflux across the peritubular membrane and the apparent permeability of the peritubular membrane to urate were unchanged. There was no evidence of significant intracellular binding or trapping of urate. Although an increase in the initial rate of urate transport into the cells across the peritubular membrane could not be demonstrated conclusively in nonperfused tubules, the results still suggest that SITS in the bathing medium may inhibitJ _urate ^net by inhibiting urate movement from the cells to the lumen while actually enhancing transport from the bathing medium into the cells.     

Generation of the eosinophil chemotactic factor (ECF) from various cell types by melittin

The peptide melittin, the main constituent of bee venom is a potent stimulus for the generation of an eosinophil chemotactic factor (ECF) from human polymorphonuclear neutrophils, rat mast cells and rat peritoneal cells depleted in mast cells. Optimal EFC induction required a sublytic activation of the cells. With each cell type the kinetics of ECF generation were similar in that after an early rise in activity a steep fall off occurred at later times of incubation suggesting a mechanism of inactivation. The induction of ECF by melittin is increased in the presence of calcium. The polar portion of the melittin molecule (aminoacids 20–26) is responsible for the generation of the chemotactic activity. Other peptides of honey bee venom such as the mast cell degranulating peptide (MCD) or apamine do not initiate ECF release. It appears that melittin leads to ECF induction via the phospholipase A₂-arachidonic acid dependent pathway of cell activation. Our data suggests that the lipid mediator ECF can be obtained from phagocytes and mast cells thus indicating the interdependence of inflammatory reactions.     

大鼠嗅球和鼻腔嗅粘膜成鞘细胞的形态学研究

目的：观察大鼠嗅神经成鞘细胞在嗅球和嗅粘膜的分布及其形态学结构特征，研究其与中枢神经再生的关系。方法：Luxol固蓝染色、Mallory染色和NGFRp75免疫组织化学染色结合透射电镜观察。结果：在嗅球纤维层的成鞘细胞随神经纤维呈纵向排列，在嗅小球层的成鞘细胞则围绕着嗅小球环行排列。在嗅粘膜的成鞘细胞位于柱状上皮深方，沿基底膜分布。成鞘细胞的胞体为细长梭形，有较长的突起，细胞核呈圆形或椭圆形。在嗅小球周围或嗅粘膜内的成鞘细胞呈NGFRp75免疫反应阳性。在电镜下，嗅球成鞘细胞的纵断面上可见其胞体呈长梭形，细胞核为不规则形，核仁清晰。在胞体的周围有大量的平行神经纤维纵向排列，在放大的横断面上，可见在1个成鞘细胞的细胞核周围有数根神经纤维被胞质包裹在一起。结论：嗅成鞘细胞是一种特殊的胶质细胞，分布于嗅球的纤维层、嗅小球层和嗅粘膜内。嗅神经成鞘细胞的胞体细长，有较长突起，其轴系膜紧密包裹成束的无髓神经纤维。     

Bilateral Occlusion of Carotid Artery in Awake Hypertensive Rats (SHR-SP) as a Model of Global Cerebral Ischemia

Bilateral occlusion of carotid arteries in awake hypertensive rats (SHR-SP) was used as a model of global brain ischemia (duration of occlusion — until appearance of seizures). In normotensive rats (WKY), no seizures developed over 60 min. We revealed swelling of mitochondria in dendrites of hippocampal CA1 pyramidal cells, which was more pronounced in SHP-SP than in WKY rats. Blood pressure and heart rate in SHR-SP rats increased starting from the first minutes of occlusion, while in WKY rats these parameters remained unchanged. We proved that bilateral occlusion of the carotid arteries in awake SHR-SP rats can be used as an adequate model of global cerebral ischemia. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 146, No. 12, pp. 627–630, December, 2008     

子宫畸形患者HOXA13基因同源结构域分析

目的探讨中国子宫畸形患者中HOXA13基因同源结构域是否存在突变及其相关性分析。方法国外文献报道手-足-生殖器综合征（hand-foot-genital syndrome,HFGS）患者中发现HOXA13基因2号外显子同源结构域存在点突变,而此综合征的女性患者部分症状表现为子宫畸形,因此对58例中国子宫畸形患者和54例正常对照者进行HOXA13基因同源结构域检测,PCR扩增目的片断后自动化测序分析基因2号外显子同源结构域区域。结果HOXA13基因同源结构域直接自动化测序分析结果显示,在患者和对照者中均没有突变发生。结论中国妇女子宫畸形的发生可能与HOXA13基因同源结构域突变无关。     

Dual function of Langerhans cells in skin TSLP-promoted TFH differentiation in mouse atopic dermatitis

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Ultrastructural and biochemical studies on the intestinal absorption of a medium-chain triglyceride (MCT), tricaprylin

The intestinal absorption of a medium-chain triglyceride (MCT) was studied by electron microscopy and biochemical analysis. In jejunal absorptive cells of rats fed tricaprylin, the smooth endoplasmic reticulum in the apical cytoplasm appeared to increase in number and contained one or two particles about 40–80 nm in diameter that were less electron dense and similar in size and profile to very low density lipoprotein. Similar particles were also observed packed in the dilated Golgi sacs and in the extended intercellular spaces. These particles were remarkably increased in number as compared with those in fasted rats. Biochemical analysis of lymph from the main intestinal lymph duct showed that caprylate was apparently demonstrated only in the lymph of rats given tricaprylin at the maximum rate 3h after oral administration. The study strongly suggests that medium-chain triglyceride is at least in part transported via lacteal, possibly in the form of very low density lipoprotein.     

磷脂酰胆碱抗氧化效应及对遗传损伤的保护作用

磷脂酰胆碱５００ｍｇ／ｋｇ灌胃２０日可使Ｏ_３环境中的小鼠超氧化物歧化酶（ＳＯＤ）活性显著增强，血浆丙二醛（ＭＤＡ）含量及外周血正染红细胞（ＮＣＥ）微核率明显下降。结果提示：磷脂酰胆碱具有抗氧化作用及拮抗自由基造成遗传的损伤。进一步证实了自由基在微核形成中具有重要意义。