间接免疫过氧化物酶技术鉴定猪和牛的肥大细胞

用小鼠抗人肥大细胞类胰蛋白酶单克隆抗体ＡＡ１,ＡＡ３及ＡＡ５的间接免疫过氧化物酶技术对经Ｃａｒｎｏｙ液或中性缓冲福尔马林固定的猪和犊牛空肠,舌及胸腺的石蜡切片进行了免疫染色。对猪和牛的肥大细胞特异性免疫染色与常规的组织化学染色的结果进行了比较。     

鸡中枢淋巴器官肥大细胞的组织化学与形态学

对哺乳动物的,特别是啮齿动物和人类肥大细胞已有了比较深入的研究, 但关于家禽肥大细胞的研究很少.本研究旨在阐明鸡中枢淋巴器官中肥大细胞的组织化学与形态学特征.本研究证实Carnoy 氏液是鸡肥大细胞的优良的固定液,而中性缓冲福尔马林(NBF) 却阻断了大多数肥大细胞的着染力.甲苯胺蓝和阿尔新蓝是鸡肥大细胞的良好的染料,但阿尔新蓝能使更多的肥大细胞着染,虽然其也可使杯状细胞着染.作者的一种新的染色法, 长时间阿尔新蓝染色(LAB-S)可用于NBF固定的组织中肥大细胞的染色,因为其着染的细胞数与Carnoy 氏液固定甲苯胺蓝染色的细胞数无显著差异(P<0.001).在胸腺髓质中见有大量的肥大细胞,而胸腺皮质仅可见个别肥大细胞位于血管周围及小叶间结缔组织中.腔上囊的皮质与髓质中很少见有肥大细胞.肥大细胞有血管周围分布的倾向,但一个有趣的发现是血管内偶尔也有个别肥大细胞.电镜下可见肥大细胞的胞浆颗粒内充满无定形的颗粒状基质,但其电子密度有的较高,有的较低.少数胞浆颗粒内有旋涡状及网状亚微结构.但未见有人类肥大细胞胞浆颗粒内特征性的晶格状和卷轴状的亚微结构,也未见到在绵羊肥大细胞中描述过的特殊亚微结构.     

Eosinophils and mast cell homogeneity of the guinea pig eyelid skin, conjunctiva, and ileum

Mast cell heterogeneity has been described on the basis of differential staining reactions, light microscopic morphology, anatomic location, degranulation after polyamines, biochemical contents, growth requirements, and reactions to lymphokines. We have demonstrated typical "connective-tissue mast cells" by using anatomic criteria, histological staining reactions, electron microscopy, and reaction to compound 48/80 in the guinea pig conjunctiva, eyelid skin, and ileum. A second, much larger population of cells in the ileal mucosa and the conjunctiva, and rarely in the eyelid skin stained reddish-blue with acid toluidine blue in tissue fixed in ethanol-acetate-lead subacetate (BLA) and with alkaline Giemsa in formaldehyde-fixed tissue, did not stain with ethanolic or acid toluidine blue in formaldehyde-fixed tissue or with alkaline Giemsa in BLA-fixed tissue, and did not degranulate after 48/80 treatment. These are features of the rat intestinal "mucosal mast cells"; however, ultrastructural and light microscopic studies with the orcein Giemsa stain demonstrated these cells in the guinea pig to be eosinophils. Tissue culture, biochemical, and immunological studies indicate the existence of a second type of mast cell (bone-marrow-derived mast cell), ultrastructurally almost indistinguishable from the connective tissue mast cell. Our studies demonstrate only one mast cell type in the guinea pig and support the contention that other forms of mast cells are immature forms or variants of the connective-tissue mast cell.     

不同固定液和染色方法显示山羊子宫内肥大细胞效果的比较

目的探讨用不同固定液和染色方法对显示处于间情期山羊子宫肥大细胞的影响。方法用四种不同的固定方法,应用改良甲苯胺蓝（MTB）染色法和阿尔辛蓝-番红花红（AB-S）染色法显示处于间情期山羊子宫肥大细胞。结果山羊子宫组织采用Carnoy氏液固定,MTB和AB-S染色对所有的肥大细胞均可获得良好的染色反应,但10％中性福尔马林,4％多聚甲醛,Bouin氏液固定的组织仅有少量肥大细胞着染。结论MTB和AB-S染色法均是山羊子宫肥大细胞良好的染色方法。     

Effects of strong electrolytes on the iron alum-Alcian Blue-Safranin staining of mast cell granules of the rat

Summary Rat mast cells fixed in Carnoy's fluid were stained with iron alum-Alcian Blue-Safranin solution after pre-treatment with strong electrolyte solutions including acids, neutral salts and alkalis. Although both red and blue mast cells were observed without pre-treatment, most mast cells were stained blue and a few red when they were stained after the pre-treatment. Mast cell granules contain salt complexes formed between basic proteins and acidic polysaccharides through ionic linkages between protein basic groups and polysaccharide sulphate and carboxylic acid groups. It is suggested that when sections are treated with strong electrolyte solutions, complexes are broken by disruption of ionic linkages and sulphate and carboxylic acid groups of polysaccharides masked by basic proteins become available for binding Alcian Blue. This was confirmed by model experiments performed with smears of a heparin-lysozyme complex.When mast cells were fixed in aldehyde-containing fixatives, no effects of strong electrolyte solutions on the staining properties of mast cell granules were revealed.     

尼罗罗非鱼消化道肥大细胞的组化性质

实验采用改良甲苯胺蓝(MTB)、阿利新蓝-沙黄(AB/SO)、甲基绿-派洛宁(MG-P)、天青Ⅱ-伊红-瑞氏混合液和硫堇5种组化染色法,对尼罗罗非鱼(Nile tilapia)消化道组织中的肥大细胞(Mast cell,MC)组化性质进行研究。尼罗罗非鱼的食管、胃及小肠壁内均显示有肥大细胞,在食管和胃的切片标本上肥大细胞主要分布在黏膜固有层和胃腺体之间。在肠道中的肥大细胞主要分布在黏膜固有层和肠上皮下方,少量肥大细胞存在于黏膜下层结缔组织中。细胞呈圆形、椭圆形,也有长梭形的。而且肥大细胞有沿血管分布的特点。5种组化染色结果表明:AB/SO、MTB和MG-P显示的MC效果较好,尤其AB/SO染色效果最好,肥大细胞轮廓清楚,胞质颗粒较清晰;尼罗罗非鱼肥大细胞胞浆颗粒都呈红色,即肥大细胞胞浆主要含肝素,不含组胺。天青Ⅱ-伊红-瑞氏混合液染色效果也很好,但被染的肥大细胞较少;80%乙醇硫堇染色,在尼罗罗非鱼消化道各段组织中均未能鉴定出肥大细胞。尼罗罗非鱼消化道肥大细胞大多分布于浅层的黏膜或血管、腺体周围的结缔组织等易表露于环境抗原的位点。罗非鱼消化道黏膜层结缔组织中的肥大细胞与大多数脊椎动物的肥大细胞一样,具有沿血管分布的特性,说明硬骨鱼的肥大细胞如哺乳动物肥大细胞一样与血管有着密切的关系。       

Nuclear stains with soluble metachrome metal mordant dye lakes. The effect of chemical endgroup blocking reactions and the artificial introduction of acid groups into tissues.

Following our study on the effect of deoxyribonucleic acid (DNA) extraction on nuclear staining with soluble metal mordant dye lakes covering 29 dye lakes we chose a series of lakes representing the three groups: (1) readily prevented by DNA removal, (2) weakened by DNA extraction but not prevented, (3) unaffected by DNA removal, for application of other endgroup blockade reactions. The lakes selected were alum and iron hematoxylins, iron alum and ferrous sulfate galleins, Fe2+ gallo blue E, iron alum celestin blue B, iron alum fluorone black and the phenocyanin TC-FeSO4 sequence. Azure A with and without an eosin B neutral stain, was used as a simple cationic (and anionic) dye control. Methylation was less effective than with simple cationic dyes, but did weaken celestin blue, gallo blue E and phenocyanin Fe2+ nuclear stains. These dyes also demonstrate other acid groups: acid mucins, cartilage matrix, mast cells, central nervous corpora amylacea and artificially introduced carboxyl, sulfuric and sulfonic acid groups. Alum hematoxylin stained cartilage weakly and demonstrated sulfation and sulfonation sites. The iron galleins, iron fluorone black and acid iron hematoxylin do not. A pH 4 iron alum hematoxylin gave no staining of these sites; an alum hematoxylin acidified with 1% 12 N HCl gave weaker results. Deamination prevented eosin and orange G counterstains but did not impair nuclear stains with any of the mordant dye lakes. The simple acetylations likewise did not alter mordant dye nuclear staining, the Skraup reagent gave its usual sulfation effect on other tissue elements, but did not alter nuclear stains by mordant dyes. The mordant dyes do not bind to periodic acid engendered aldehyde sites and p-toluidine/acetic acid and borohydride aldehyde blockades did not alter mordant dye lake nuclear staining. Nitration by tetranitromethane, which blocks azo coupling of tyrosine residues, did not alter nuclear staining by the mordant dye lakes. Benzil at pH 13, which prevents the beta-naphthoquinone-4-Na sulfonate (NQS) arginine reaction and the Fullmer reaction of basic nucleoprotein, did not affect iron gallein, iron or alum hematoxylin stains of nuclei or lingual keratohyalin.     

Mast and enterochromaffin-like cells of the gastric mucosa]

An attempt has been made to reveal simultaneously both mast and ECL cells in the fundic mucosa of some laboratory animals and man. In Bouin fluid fixed specimens, toluidine blue pH 5.0 and alcian blue pH 1.0 failed to reveal mucosal mast cells in rats and mice only. In those animals mucosal mast cells became demonstrable in Carnoy fluid fixed tissues after staining with alcian blue pH 1.0. A double staining technique has been applied using Grimelius silver method followed by staining either with toluidine blue after acid hydrolysis or with alcian blue. Both mast and ECL cells became visible showing here and there their close arrangement. The latter might be a point for some functional relations between both cell types.     

Staining Mast Cells for Morphometric Evaluation on an Image Analysis System

Multiple skin sections from three nonhuman primates (Macaca mulatta) and three hairless guinea pigs (Cavia porcellus) were stained with 12 different histologic stains to determine whether mast cells could be selectively stained for morphometric analysis using an image analysis system (IAS). Sections were first evaluated with routine light microscopy for mast cell granule staining and the intensity of background staining. Methylene blue-basic fuchsin and Unna's method for mast cells (polychrome methylene blue with differentiation in glycerin-ether) stained mast cell granules more intensely than background in both species. Toluidine blue-stained sections in the guinea pig yielded similar results. Staining of the nuclei of dermal connective tissue was enhanced with the methylene blue-basic fuchsin and toluidine blue stains. These two stains, along with the Unna's stain, were further evaluated on an IAS with and without various interference filters (400.5-700.5 nm wavelengths). In both the methylene blue-basic fuchsin and toluidine blue stained sections, mast cell granules and other cell nuclei were detected together by the IAS. The use of interference filters with these two stains did not distinguish mast cell granules from stained nuclei. Unna's stain was the best of the 12 stains evaluated because mast cell granule staining was strong and background staining was faint. This contrast was further enhanced by interference filters (500.5-539.5 nm) and allowed morphometric measurements of mast cells to be taken on the IAS without background interference.     

A Simplified Method for Staining Mast Cells with Astra Blue

The copper phthalocyanin dye astra blue has been used to stain differentially mast cells of the intestine; however, the procedure has not been used widely because of the difficulty in preparing and using the dye solution. Described here is a simple, reliable, and consistent method for selectively staining mast cells using a dye solution that may be prepared in any laboratory without the aid of sophisticated pH metering equipment. Astra blue is mixed with an alcoholic solution containing MgCl₂ · 6H₂O and the pH indicator pararosaniline hydrochloride. Concentrated hydrochloric acid is added dropwise, changing the dye mixture from purple to violet and then to blue. In this low range the weakly ionizing ethanol provides a more stable hydrogen ion concentration than the corresponding aqueous solutions used previously. Alcoholic acid fuchsin is a convenient counterstain, and this simple procedure then provides good contrast between the blue staining mast cell granules and the red tissue background.     

A simplified method for staining mast cells with astra blue

The copper phthalocyanin dye astra blue has been used to stain differentially mast cells of the intestine; however; the procedure has not been used widely because of the difficulty in preparing and using the dye solution. Described here is a simple, reliable, and consistent method for selectively staining mast cells using a dye solution that may be prepared in any laboratory without the aid of sophisticated pH metering equipment. Astra blue is mixed with an alcoholic solution containing MgCl2-6H2O and the pH indicator pararosaniline hydrochloride. Concentrated hydrochloric acid is added dropwise, changing the dye mixture from purple to violet and then to blue. In this low range the weakly ionizing ethanol provides a more stable hydrogen ion concentration than the corresponding aqueous solutions used previously. Alcoholic acid fuchsin is a convenient counterstain, and this simple procedure then provides good contrast between the blue staining mast cell granules and the red tissue background.     

Distribution of chymase-containing mast cells in human bronchi.

Mast cell chymase stimulates secretion from cultured airway gland serous cells and hydrolyzes bronchoactive peptides in vitro. To explore the likelihood of these interactions occurring in situ, we examined the distribution and concentration of chymase-containing mast cells near glands and smooth muscle of major human bronchi from eight individuals without known airway disease. Total airway mast cells and the subset of mast cells containing chymase were detected by staining for methylene blue metachromasia and chloroacetate esterase activity, respectively. The percentage of chymase-containing mast cells was found to differ strikingly among bronchial tissue compartments. Near glands, for example, the concentration of chymase-positive mast cells (640 +/- 120 cells/mm3) was 73 +/- 9% that of total mast cells (910 +/- 130 cells/mm3), whereas in smooth muscle the concentration of chymase-positive mast cells (450 +/- 200 cells/mm3) was only 14 +/- 4% that of total mast cells (2920 +/- 620 cells/mm3). Of all chymase-containing mast cells in the airway subepithelium, 30 +/- 4% were located within 20 microns of submucosal glands. Although the percentage of chymase-containing cells varied, the absolute concentration of chymase-containing mast cells was similar in all compartments. These results reveal a differential distribution of mast cell subpopulations in human airway and suggest that mast cells containing chymase are near gland and smooth muscle targets.     

Identification of a chymotrypsin-like proteinase in human mast cells

An antiserum was produced against a chymotryptic proteinase purified from human skin. The antiserum did not cross-react with human leukocyte cathepsin G and elastase, rat mast cell proteinase I, and human skin tryptase. Indirect immunofluorescent staining of frozen skin sections to localize the proteinase showed cytoplasmic staining of cells scattered about the papillary dermis and around blood vessels and appendages. Restaining these sections with toluidine blue revealed that the fluorescently stained cells contained metachromatically staining granules, the major distinguishing feature of mast cells. A similar correlation was found in lung tissue. Ultrastructural studies employing the ferritin bridge technique to immunologically identify the proteinase additionally localized the proteinase to mast cell granules. Biochemical and immunochemical characterization of chymotryptic activity solubilized from isolated human lung mast cells identified a chymotryptic proteinase that may be identical to the skin chymotryptic proteinase. These studies establish that human skin mast cells contain a chymotrypsin-like proteinase that is a granule constituent and provide evidence that indicates a comparable proteinase is also present in lung mast cells.     

Nuclear stains with soluble metachrome metal mordant dye lakes

Summary Following our study on the effect of deoxyribonucleic acid (DNA) extraction on nuclear staining with soluble metal mordant dye lakes covering 29 dye lakes we chose a series of lakes representing the three groups: (1) readily prevented by DNA removal, (2) weakened by DNA extraction but not prevented, (3) unaffected by DNA removal, for application of other endgroup blockade reactions. The lakes selected were alum and iron hematoxylins, iron alum and ferrous sulfate galleins, Fe²⁺ gallo blue E, iron alum celestin blue B, iron alum fluorone black and the phenocyanin TC-FeSO₄ sequence. Azure A with and without an eosin B neutral stain, was used as a simple cationic (and anionic) dye control.Methylation was less effective than with simple cationic dyes, but did weaken celestin blue, gallo blue E and phenocyanin Fe²⁺ nuclear stains. These dyes also demonstrate other acid groups: acid mucins, cartilage matrix, mast cells, central nervous corpora amylacea and artificially introduced carboxyl, sulfuric and sulfonic acid groups. Alum hematoxylin stained cartilage weakly and demonstrated sulfation and sulfonation sites. The iron galleins, iron fluorone black and acid iron hematoxylin do not. A pH 4 iron alum hematoxylin gave no staining of these sites; an alum hematoxylin acidified with 1% 12 N HCl gave weaker results.Deamination prevented eosin and orange G counterstains but did not impair nuclear stains with any of the mordant dye lakes. The simple acetylations likewise did not alter mordant dye nuclear staining, the Skraup reagent gave its usual sulfation effect on other tissue elements, but did not alter nuclear stains by mordant dyes.The mordant dyes do not bind to periodic acid engendered aldehyde sites and p-toluidine/acetic acid and borohydride aldehyde blockades did not alter mordant dye lake nuclear staining. Nitration by tetranitromethane, which blocks azo coupling of tyrosine residues, did not alter nuclear staining by the mordant dye lakes¹. Benzil at pH 13, which prevents the -naphthoquinone-4-Na sulfonate (NQS) arginine reaction and the Fullmer reaction of basic nucleoprotein, did not affect iron gallein, iron or alum hematoxylin stains of nuclei or lingual keratohyalin.Assisted by Contract Nol-CB-43912 National Cancer Institute     

虎纹蛙消化道肥大细胞类胰蛋白酶免疫组化研究

研究采用小鼠抗人肥大细胞类胰蛋白酶单克隆抗体AA1,应用ElivisionTM plus免疫组化染色法对虎纹蛙(Rana tigrina rugulosa)消化道组织中类胰蛋白酶阳性肥大细胞存在的可能性进行研究。研究发现单克隆抗体AAl可与中性缓冲福马林液固定的虎纹蛙组织的肥大细胞获得良好的交叉反应,类胰蛋白酶阳性细胞胞浆染成棕黄色,证实虎纹蛙肥大细胞胞浆颗粒中也存在类胰蛋白酶。虎纹蛙组织中AA1免疫染色阳性细胞的分布,与AB/SO和改良甲苯胺兰染色阳性细胞的分布存在较大的差异:虎纹蛙类胰蛋白酶阳性细胞数量很少,且阳性反应比人胃癌间质肥大细胞弱,主要见于黏膜型肥大细胞(MMC)分布区域,如消化道黏膜上皮下方和固有层,少量分布于肠绒毛基底部及食管腺和胃腺周围。而在结缔组织型肥大细胞(CTMC)分布区域,如消化道黏膜下层结缔组织中却未见类胰蛋白酶阳性细胞。AB/SO和改良甲苯胺兰染色阳性细胞数量多,广泛分布于消化道黏膜固有层、黏膜下层、腺体之间、肌间及外膜结缔组织,说明并不是所有的虎纹蛙肥大细胞都含有类胰蛋白酶。很有可能是虎纹蛙MMC中含有类胰蛋白酶,而CTMC中不含类胰蛋白酶。虎纹蛙类胰蛋白酶阳性细胞数量很少,且阳性反应比人胃癌间质肥大细胞弱,说明虎纹蛙肥大细胞胞浆颗粒类胰蛋白酶含量较少,虎纹蛙属于低等脊椎动物,可能与生物进化水平较低有关,有待进一步研究。       

Methods of Staining Plant Tissues for Differentiating the Natural Plant Oils from Petroleum Spray Oils

Petroleum, spray oils in sections of plant tissue have been distinguished from the plant oils by staining the fresh sections in the following dye solution: To a saturated aqueous solution of Nile blue sulfate, 0.5% sulfuric acid is added and the mixture is boiled under a reflux condenser for 4 or 5 hours. It should be as nearly alkaline as possible without a change of color. A solution of 50% alcohol and 50% acetone is then saturated with oil red O. One part of the Nile blue sulfate solution is then added to two parts of the oil red O solution. Allow to settle over night and filter. Stain several hours. Rinse in water and mount in glycerin jelly. A short discussion of the merits of this method and the differentiation of the spray oils by means of indophenol blue are also given.     

Bovine mast cells: distribution, density, heterogeneity, and influence of fixation techniques

Mast cells can be distinguished according to various characteristics: rodent mast cells have been subtyped by histochemical criteria, whereas canine and human mast cells have been classified according to their proteases. Comparisons of mast cells from different species have therefore resulted in contradictory and confusing opinions on mast cell heterogeneity. Thus, it is essential to obtain species-specific data on mast cell density and heterogeneity. The present study was carried out to determine the physiological distribution of mast cell numbers and types in bovines according to tissue location, staining, and fixation methods. Samples were fixed in formalin or Carnoy’s fluid. The average number of mast cells was determined by using a metachromatic staining method. Protease content of mast cells was examined with a double-enzyme-immunohistochemical staining technique. Three mast cell subtypes were distinguished: T-, TC-, and C-mast cells. The T-mast cell was the predominant subtype in nearly all investigated organs and tissue locations. Only tryptase-positive mast cells could be demonstrated in bovine skin and uterus. No chymase activity was found in these organs, regardless of the fixation type. A larger number of mast cells was observed after fixation in Carnoy’s fluid. The three different mast cell subtypes were only demonstrated in formalin-fixed tissue; chymase-positive mast cells were not found after fixation in Carnoy’s fluid. Increasing experimental data suggest that mast cell subtypes have different functions in promoting and modulating inflammation and in remodeling the extracellular matrix. Since mast cell tryptase and chymase have different functional properties, these results may clarify the different reaction patterns observed in various organs and species.     

Porcine Intestinal Mast Cells. Evaluation of Different Fixatives for Histochemical Staining Techniques Considering Tissue Shrinkage

Staining of mast cells (MCs), including porcine ones, is critically dependent upon the fixation and staining technique. In the pig, mucosal and submucosal MCs do not stain or stain only faintly after formalin fixation. Some fixation methods are particularly recommended for MC staining, for example the fixation with Carnoy or lead salts. Zinc salt fixation (ZSF) has been reported to work excellently for the preservation of fixation-sensitive antigens. The aim of this study was to establish a reliable histological method for counting of MCs in the porcine intestinum. For this purpose, different tissue fixation and staining methods that also allow potential subsequent immunohistochemical investigations were evaluated in the porcine mucosa, as well as submucosa of small and large intestine. Tissues were fixed in Carnoy, lead acetate, lead nitrate, Zamboni and ZSF and stained subsequently with either polychromatic methylene blue, alcian blue or toluidine blue. For the first time our study reveals that ZSF, a heavy metal fixative, preserves metachromatic staining of porcine MCs. Zamboni fixation was not suitable for histochemical visualization of MCs in the pig intestine. All other tested fixatives were suitable. Alcian blue and toluidine blue co-stained intestinal goblet cells which made a prima facie identification of MCs difficult. The polychromatic methylene blue proved to be the optimal staining. In order to compare MC counting results of the different fixation methods, tissue shrinkage was taken into account. As even the same fixation caused shrinkagedifferences between tissue from small and large intestine, different factors for each single fixation and intestinal localization had to be calculated. Tissue shrinkage varied between 19% and 57%, the highest tissue shrinkage was found after fixation with ZSF in the large intestine, the lowest one in the small intestine after lead acetate fixation. Our study emphasizes that MC counting results from data using different fixation techniques can only be compared if the respective studyimmanent shrinkage factor has been determined and quantification results are adjusted accordingly.Key words: mast cell, swine, fixation, tissue shrinkage factor     

Concomitant Staining of Mast and Parietal Cells in Human Gastric Mucosa

A simple technique for concomitant staining of mast and parietal cells in the same section is described. Mast cells were stained by alcian blue or astra blue in methanol-formalinacetic acid fixed biopsies of gastric mucosa. Parietal cells were visualized by Dolichos biflorus lectin binding.     

几种肥大细胞染色方法的比较

运用ABC—爱先蓝—PAS混合染色及PAP技术对大鼠肝、胃、肠及DAB诱发的大鼠肝癌中肥大细胞进行了染色对比实验,结果表明:Carnoy及福尔马林等固定液固定的组织内肥大细胞均能被爱先蓝染色成蓝色,其染色时间不同,该种染色方法可作为一种常规的染色方法,用于确定肥大细胞在组织中的分布及数量。ABC—爱先蓝—PAS混合染色方法及PAP技术均能准确、有效地确定肥大细胞(MC)性质。ABC—爱先蓝—PAS混合染色使结缔组织肥大细胞(CTMC)呈棕褐色,周边略蓝色。粘膜肥大细胞(MMC)则呈蓝色,通过不同颜色的显示,可清楚地将CTMC与MMC区分开来。PAP方法具更高的特异性。但有关的抗体来源缺乏,因此在无特异Ⅰ抗体的情况下,ABC—爱先蓝—PAS混合染色方法亦可视为鉴别两类不同性质MC的一种较为理想的方法。