Early myelin lesions in experimental allergic neuritis

We examined the evolution of demyelination in spinal roots of Lewis rats immunized with whole nerve and complete Freund' adjuvant. Roots were morphologically normal until 11 days after immunization, when we found endoneurial edema and myelin vesiculation in the absence of mononuclear cell contacts. Macrophage-associated myelin stripping was not detected until day 12. Macrophage infiltrations were extensive by day 14, but lymphocytes were sparse. These observations indicate that in experimental allergic neuritis, myelin injury may occur before macrophage-mediated demyelination, and provide support for an early role of serum factors in the development of this disorder.     

Myelin basic protein content of aggregating rat brain cell cultures treated with cytokines and/or demyelinating antibody: Effects of macrophage enrichment

The demyelinative potential of the cytokines interleukin-1α (IL-1α), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) has been investigated in myelinating aggregate brain cell cultures. Treatment of myelinated cultures with these cytokines resulted in a reduction in myelin basic protein (MBP) content. This effect was additively increased by anti-myelin/oligodendrocyte glycoprotein (α-MOG) in the presence of complement. Qualitative immunocytochemistry demonstrated that peritoneal macrophages, added to the fetal telencephalon cell suspensions at the start of the culture period, successfully integrated into aggregate cultures. Supplementing the macrophage component of the cultures in this fashion resulted in increased accumulation of MBP. The effect of IFN-γ on MBP content of cultures was not affected by the presence of macrophages in increased numbers. © 1994 Wiley-Liss, Inc.     

Bacterial endotoxin induces [Ca2+]i transients and changes the organization of actin in microglia

We have employed amoeboid microglia purified from primary cultures of neonatal rat brain to examine the effect of bacterial lipopolysaccharide (LPS), a potent activator of immune cells, on intracellular calcium concentration ([Ca²⁺]i) in brain macrophages. In single brain macrophages loaded with indo 1, pulse administration of LPS elicited a rapid and transient increase in [Ca²⁺]i From a total of 70 cells examined, all responded to LPS with a similar [Ca²⁺]i transient, indicating a good homogeneity of the cell population with regard to the LPS response. It was concluded that the rise of cytosolic [Ca²⁺]i originated from intracellular stores because the response to LPS occured similarly in the presence or in the absence of extracellular Ca²⁺. A second administration of LPS to the same cells resulted in a second but reduced [Ca²⁺]i transient. In contrast to the first response to LPS, this second response was totally dependent on the presence of Ca²⁺ in the extracellular medium. The first response to LPS was strongly inhibited by ruthenium red and could be suppressed in a reversible manner by pre incubating the cells with caffeine in the absence of Ca²⁺ in the extracellular medium. These results indicate that caffeinesensitive intracellular Ca²⁺ stores may be the major source of Ca²⁺ in the response of brain macrophages to LPS. The possible release of Ca²⁺ from phosphatidylinositol(3,4,5)-trisphosphate (IP₃)-sensitive stores in brain macrophages was also evaluated by stimulating cells with the IP₃-mobilizing agonist histamine. Brain macrophages were heterogeneous with regard to the histamine response since histamine induced a [Ca²⁺]i rise in only 30% of cells examined. The increase in [Ca²⁺]i triggered by LPS may in turn activate several intracellular events involved in the transition from one microglial functional state to another. We examined the effect of LPS on the state of organization of actin, which is an essential component of chemoattractant signal transduction. Immunofluorescence staining with anti-actin antibody which recognizes actin in both filamentous and nonfilamentous configurations, indicated that LPS produced drastic changes in the actin organization. LPS-treated cells appeared more intensely fluorescent than untreated cells due to the concentration of diffuse fluorescence near the center of the cell. In addition, prominent fluorescent dots were present in the subplasmalemmal region in cells stimulated with LPS. This specific LPS-induced reorganization of actin was also observed in cells preincubated in the external medium without Ca²⁺. Thus, it is likely that the LPS-induced mobilization of Ca²⁺ from intracellular stores may be responsible for the changes observed in the actin organization. © 1994 Wiley-Liss, Inc.     

In vitro and in vivo effects of tachykinins on immune cell function in guinea pig airways

The effects of sensory neuropeptides substance P (SP) and neurokinin A (NKA) on immune cell recruitment and macrophage activation were determined. Guinea pigs exposed to capsaicin aerosol exhibited eosinophil and neutrophil influx into their bronchoalveolar lavage (BAL) fluid 24 h after treatment; SP aerosol elicited eosinophil influx, whereas NKA aerosol exposure caused neutrophil recruitment. Inhalation of capsaicin, NKA or SP aerosols also enhanced superoxide production induced by zymosan in cultured alveolar macrophages. Incubation of alveolar macrophages with SP or NKA in culture for the same time (24 h) did not potentiate the response to zymosan. Hence, tachykinin-mediated airway effects may not be the result of direct actions on target cells but rather involve alternate mechanisms and mediators which do not necessarily reflect in vitro data.     

苦参碱对体外小鼠脾细胞增殖及腹腔巨噬细胞释放白细胞介素－1及－6的影响

目的：研究苦参碱对小鼠脾细胞增殖及腹腔巨噬细胞释放白细胞介素１（ＩＬ１）及６（ＩＬ６）的影响．方法：［３Ｈ］ＴｄＲ参入法测定脾细胞增殖，胸腺细胞增殖法和Ｂ９细胞增殖ＭＴＴ法测定ＩＬ１和ＩＬ６活性．结果：苦参碱（１２５－５００ｍｇ·Ｌ－１）以剂量依赖方式显著抑制ＣｏｎＡ及脂多糖（ＬＰＳ）诱导的小鼠脾细胞增殖以及ＬＰＳ诱导的小鼠腹腔巨噬细胞释放ＩＬ１和ＩＬ６．结论：苦参碱抑制体外小鼠脾细胞增殖及巨噬细胞分泌ＩＬ１和ＩＬ６．     

低剂量电离辐射对小鼠脾巨噬细胞功能的影响

本研究采用昆明小鼠，低剂量Ｘ射线全身照射５０～２５０ｍＧｙ，剂量率１２．５ｍＧｙ／ｍｉｎ。停照后不同时间处死动物，取出脾脏，用贴壁法分离脾巨噬细胞（Ｍφ）和淋巴细胞，检测受照射脾Ｍφ的某些功能变化。结果表明，受照射的脾Ｍφ对受照射的脾淋巴细胞ＣｏｎＡ反应增强，ＩＬ一１分泌增多，抑瘤作用增高。     

Neutral-Red Uptake and Expression of Monocytic Antigens in Amniotic-Fluid Mononuclear Phagocytes: Evaluation of a Novel Approach for Prenatal Diagnosis of Neural-Tube Defects

ABSTRACT: In cases of fetal neural-tube defects macrophages are present in the amniotic fluid. We found that these viable phagocytic cells take up neutral-red and are easily identified as “red cells” by microscopic examination. This method is suitable for the rapid identification and counting of amniotic-fluid macrophages in suspension. We have studied 298 amniotic fluid samples. In the 226 normal cases studied, 0 to 1,200 macrophages per milliliter amniotic fluid have been found. In contrast, we found 1,250 to 99,000 macrophages per milliliter amniotic fluid in our 70 open neural tube defect (ONTD) cases. Statistical evaluation was performed to estimate the normal and pathologic ranges. Specificity and sensitivity of the neutral-red test and predictive value of positive and negative results have been calculated and presented in comparison with alpha-fetopro-tein (AFP) determinations and ultrasonic methods. In 5 cases of anencephaly and 7 normal cases amniotic fluid cells were studied by immunocytochemistry: mononuclear cells present in the abnormal cases showed intense immunoreactivity for the Mo1 and Mo2 surface antigens of the phagocytic cell lineage.     

A simple method for the solubilisation of reduced NBT, and its use as a colorimetric assay for activation of human macrophages by gamma-interferon

We describe a simple method by which the insoluble blue formazan dye produced by the reduction of nitro blue tetrazolium can be dissolved without heating using potassium hydroxide and dimethyl sulphoxide. This modification enhances the sensitivity and increases the applications of tests performed using the microELISA method and removes variations caused by uneven cell monolayers. It also allows quantification of NBT reduced by cells adherent to coverslips or in larger wells or Petri dishes, and can be used as a sensitive assay for macrophage activation by gamma-interferon.     

睾丸切除和雄激素对小鼠腹腔巨噬细胞化学发光的影响

作者探讨了睾丸切除和外源性注射丙酸睾丸素(2.5μg/g)对小鼠腹腔M_φ的CL和细胞内cAMP的影响,并做了动态观察。睾丸切除可增强小鼠腹腔M_φ的CL强度,且在术后第2天CL值升高最显著;睾丸切除后给予丙酸睾丸素替代可部分降低CL值;给正常动物施用丙酸睾丸素亦使CL强度显著降低;而睾丸切除和注射外源性丙酸睾丸素对腹腔M_φ内cAMP无显著影响。     

Antitumor reactivity induced by liposomal MTP-PE in a liver metastasis model of colon cancer in the rat

The antitumor effects of muramyl tripeptide phosphatidylethanolamine, incorporated within the lipophilic phase of liposomes (lipMTP-PE) were studied using a model of liver metastasis of colon cancer in the rat. Intravenous immunotherapy with lipMTP-PE, when started 2 days before the inoculation of tumor cells and given twice a week, significantly reduced subsequent tumor growth in the liver. The main effect of treatment appeared to be a substantial local increase in the number of tumoricidal macrophages and lymphocytes. Tumor cell lysis by isolated macrophages in vitro, however, appeared not to be elevated above the level triggered by tumor growth alone. Therefore, the observed therapeutic effect of lipMTP-PE probably results from a combination of (1) an increase in the number of cytotoxic macrophages at the onset of metastatic growth in the liver, thus increasing the probability of lethal contacts between tumoricidal effectors and tumor cells and (2) indirect effects of lipMTP-PE, via the induction of cytokine production by liver macrophages, leading to increased numbers and/or activity of cytotoxic lymphocytes and natural killer cells.