巨噬细胞迁移抑制因子通过CC趋化因子配体2诱导巨噬细胞聚集

巨噬细胞迁移抑制因子最初是由于能抑制体外巨噬细胞随机迁移而被发现,现在它作为一种重要的调节因子参与一系列炎症性疾病过程.我们最近发现,巨噬细胞迁移抑制因子的缺失使一些由炎症介质诱发的白细胞-内皮细胞相互作用减弱,提示巨噬细胞迁移抑制因子在炎症反应中起作用的机制之一是促进白细胞聚集.……     

Direct measurement of nitroxide pharmacokinetics in isolated hearts situated in a low-frequency electron spin resonance spectrometer: implications for spin trapping and in vivo oxymetry.

The pharmacokinetics of two nitroxides were investigated in isolated rat hearts situated in a low-frequency electron spin resonance spectrometer. The spin labels 2,2,3,3,5,5-hexamethyl-1-pyrrolidinyloxy and 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxy were chosen for their physiochemical analogy to the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and its corresponding spin-trapped adduct, 2-hydroxy-5,5-dimethyl-1-pyrrolidinyloxy (DMPO-OH). The bioreductive rates of the two nitroxides were measured during constant perfusion as well as during ischemia and are discussed in terms of a two-compartment pharmacokinetic model. These data provide information necessary to the design and application of spin traps to detect oxy radicals during reperfusion of ischemic tissue and suggest the feasibility of monitoring free-radical processes in intact, functioning mammalian tissues by using a low-frequency electron spin resonance spectrometer.     

Inhibition of concanavalin A-induced acute T cell dependent hepatic damage in mice by hypothyroidism

Abstract: Aims/Background: Concanavalin A (Con A) activates T lymphocytes and causes acute T-cell-mediated hepatic injury in mice. Decreased thyroid hormonal production is associated with a variety of immunological manifestations, including inactivation of macrophages with reduced TNF production and reduced soluble IL-2 receptors in the serum. We have recently shown that hypothyroidism prevents the development of cirrhosis and also minimizes hepatic damage in rats with fulminant hepatic failure. In the present study we examined the effects of hypothyroidism on a mouse model of Con A induced T cell-mediated acute hepatitis. Methods: Hypothyroidism was induced both medically (MMI, PTU) and surgically. Eight groups of 10 mice each were studied: euthyroid controls (2 groups: water, Con A) and hypothyroid (6 groups: MMI, PTU, Surgical, MMI-Con A, PTU-Con A, Surgical-Con A). Results: Hepatic inflammation was significantly decreased in each of the Con A treated hypothyroid groups of mice. The serum transaminases, TNF-α and IL-6 levels were significantly elevated in the Con A treated group while near normal levels were found in the hypothyroid Con A treated groups (mean±SE AST: 1499±18 vs 78±10 IU/1, p<0.001; TNF: 2500±250 vs 135± 15 pg/ml. p<0.001, IL-6: 12,200±300 vs 1260±140 pg/ml, p<0.001, respectively). Conclusions: Hypothyroidism, independent of the mode of induction, can effectively inhibit the development of acute T cell-mediated liver damage in mice. These results suggest that some decrease in thyroid function might have a role in the prevention of immune mediated liver diseases.     

Existence of automaticity in anomalous bundle of Wolff-Parkinson-White syndrome.

Escape beats probably arising from the anomalous bundle were documented in 2 patients with the Wolff-Parkinson-White (WPW) syndrome. A third patient, in whom complete AV block developed both in the anomalous bundle and the normal pathway, showed the occurrence of escape beats (an escape-bigeminy pattern), as well as a regular idioventricular rhythm arising from the anomalous bundle. Phase 4 block in the anomalous bundle occurred in 7 other patients, in 4 of them spontaneously and in 3 only after the administration of ajmaline or amiodarone. Only 4 of 14 fully investigated patients (out of a total number of 23) showed absence of both escape beats and phase 4 block. The escape beats were considered as direct evidence, and the phase 4 block as indirect evidence, for the existence of automaticity in the anomalous bundle. Such evidence supports the view that the anomalous bundle, like the His bundle-branch system, may be composed of specialised tissue endowed with the property of automaticity.     

Fibronectin binding to thrombin-stimulated platelets: evidence for fibrin(ogen) independent and dependent pathways

Plasma fibronectin binds in a specific and saturable manner to thrombin- stimulated platelets. gamma-Thrombin stimulated 80% as much fibronectin binding to platelets as alpha-thrombin with conversion of less than or equal to 1% of platelet fibrinogen to fibrin. Afibrinogenemic and normal platelets bound similar quantities of fibronectin in the presence of calcium or magnesium-ethylene glycol tetra-acetic acid (EGTA). These observations indicate that fibronectin can interact with platelets without involvement of fibrin or fibrinogen. Nevertheless, two different effects of fibrin(ogen) on fibronectin binding were observed. First, exogenous fibrinogen inhibited fibronectin binding to thrombin-stimulated platelets. This inhibition was unidirectional, as fibronectin did not inhibit fibrinogen binding to ADP or thrombin- stimulated cells. Second, formaldehyde-fixed cells with surface- associated fibrin bound significant quantities of fibronectin. This interaction required calcium and did not occur on fixed cells with or without surface-bound fibrinogen. A portion of the ligand bound to fixed cells with surface-associated fibrin was modified to form a derivative with a molecular weight identical to that of the fibronectin subunit cross-linked to the alpha-chain of fibrin. This high mol wt derivative was also observed to a variable extent with living cells in the presence of magnesium or calcium but not in the presence of magnesium-EGTA. Thus, fibronectin binds to platelets by at least two mechanisms: (1) a fibrin(ogen)-independent pathway that requires divalent ions and is inhibited by exogenous fibrinogen; and (2) a fibrin-dependent pathway with an absolute calcium requirement. With nonaggregated, thrombin-stimulated platelets, the former pathway appears to predominate.     

The Effect of Replacement of Methionine by Homocystine on Survival of Malignant and Normal Adult Mammalian Cells in Culture

In tissue cultures of normal adult and malignant mammalian cells, homocystine has been substituted for methionine in a medium rich in folic acid and cyanocobalamin. Normal adult cells thrive. Three highly malignant cell types from three different species, including man, die.     

Endogenous c-src as a determinant of the tumorigenicity of src oncogenes.

We have compared the tumorigenicity of two src oncogenes, v-src and c-src(527), whose respective protein products pp60v-src and pp60c-src(527) show a different spectrum of amino acid substitutions vis-à-vis the c-src protooncogene-encoded product pp60c-src. Whereas the extent of primary tumor growth induced by c-src(527) was quite similar in the two chicken lines tested, the extent of v-src-induced tumor growth showed a marked line dependence. As examined with a line of chickens that shows immune-mediated regression of v-src-induced tumors, a weaker tumor immunity, as correlated with a greater level of primary tumor growth, resulted from inoculation of c-src(527) DNA than of v-src DNA. These observations indicated that the v-src-specific amino acid substitutions define a major tumor antigenicity. That a separate src-associated antigenicity is also targetable by the tumor immune response followed from the finding that the level of protective immunity against the growth of c-src(527) DNA-induced tumors was augmented under conditions of the prior regression of v-src DNA-induced tumors. As this latter antigenicity may include one or more c-src(527)-encoded peptides that are equivalent to c-src-encoded self peptides, these observations suggest that a host tolerance to pp60c-src can be broken so as to permit a tumor immune response based on recognition of self peptides of pp60c-src(527).     

Vector Flow Mapping in Obstructive Hypertrophic Cardiomyopathy to Assess the Relationship of Early Systolic Left Ventricular Flow and the Mitral Valve

Background

The hydrodynamic cause of systolic anterior motion of the mitral valve (SAM) is unresolved.

Objectives

This study hypothesized that echocardiographic vector flow mapping, a new echocardiographic technique, would provide insights into the cause of early SAM in obstructive hypertrophic cardiomyopathy (HCM).

Methods

We analyzed the spatial relationship of left ventricular (LV) flow and the mitral valve leaflets (MVL) on 3-chamber vector flow mapping frames, and performed mitral valve measurements on 2-dimensional frames in patients with obstructive and nonobstructive HCM and in normal patients.

Results

We compared 82 patients (22 obstructive HCM, 23 nonobstructive HCM, and 37 normal) by measuring 164 LV pre- and post-SAM velocity vector flow maps, 82 maximum isovolumic vortices, and 328 2-dimensional frames. We observed color flow and velocity vector flow posterior to the MVL impacting them in the early systolic frames of 95% of obstructive HCM, 22% of nonobstructive HCM, and 11% of normal patients (p < 0.001). In both pre- and post-SAM frames, we measured a high angle of attack >60° of local vector flow onto the posterior surface of the leaflets whether the flow was ejection (59%) or the early systolic isovolumic vortex (41%). Ricochet of vector flow, rebounding off the leaflet into the cul-de-sac, was noted in 82% of the obstructed HCM, 9% of nonobstructive HCM, and none (0%) of the control patients (p < 0.001). Flow velocities in the LV outflow tract on the pre-SAM frame 1 and 2 mm from the tip of the anterior leaflet were low: 39 and 43 cm/s, respectively.

Conclusions

Early systolic flow impacts the posterior surfaces of protruding MVL initiating SAM in obstructive HCM.