约氏疟原虫红外期成熟裂殖体的超微结构研究

用细胞色素氧化酶组织化学方法处理感染了约工疟原虫子孢子的大鼠肝脏,通过透射电镜研究红外期裂殖体的超微结构。在接种子孢子后４８小时的标本中发现一成熟裂殖体,外周仍由一寄生虫质膜包裹,膜下有许多小泡,粗面内质肉、圆形或蚕豆形具明显嵴的线粒体,以及大量成熟裂殖子。     

大鼠营养不良对约氏疟原虫子孢子侵入及其红外期发育的影响

人类的疟疾流行史表明,处于饥饿或营养不良状态下的人群,其疟疾发病率较低,临床症状较轻,动物实验证明,疟原虫红内期的发育对宿主饲料营养成份的依赖性非常明显。但宿主营养状态对子孢子侵入和红外期发育的影响尚未见有报道。本文观察了大鼠在营养不良条件下对约氏疟原虫子孢子侵入及红外期发育的影响。 将感染约氏疟原虫(Plasmodium y.yoelii)BY265 后14天的斯氏按蚊一批,剪去腹部,研磨,用     

鼠疟原虫动合子体外培养初步研究

鼠疟原虫孢子增殖期的体外培养,对疟原虫生物学以及人体疟原虫的体外培养的研究,不论在理论方面,或是实验技术的探讨,都有一定的参考价值;尤其近年来疟疾免疫学进展已进入子孢子疫苗研制阶段,对于这方面的研究,     

共聚焦激光扫描显微镜对约氏疟原虫卵囊、子孢子胞内Ca^2＋的检测方法研究

本文报告建立用共聚焦激光扫描显微镜（CLSM）观察约氏疟原虫卵囊,子孢子胞内游离Ca^2 的分布和实验检测方法,以荧光染料下Fluo-3作胞内Ca^2 指示剂,结果显示3u,4umol/L Fluo-3/Am同时加入1ul/ml25%PluronicF-127在37℃恒温下,分别孵育分离的约氏疟原虫子孢子,卵囊60min即可达到最佳的负载效果,子孢子胞内游离C^2 分布均匀,而卵囊内游离C^2 a分布不均匀,成块状分布,囊壁无效荧光,研究表明应用Fluo-3/AM和PluronicF-127结合CLSM技术是研究疟原虫卵囊,子孢子胞浆内游离Ca^2 的准确,灵敏的方法之一。     

约氏疟原虫配子体在小鼠外周血中自然消长观察

本文报道了约氏疟原虫配子体在小鼠外周血中自然消长规律以及血传代数、接种剂量、无性体寄生率对配子体消长曲线水平的影响。 约氏疟原虫(Plasmodium yoelii yoelii)是兰多(Landau)等1965年自中非共和国红树鼠(Thamnomys rutilans)体内分离获得。与伯氏疟原虫(P. berghei berghei)相比,具有毒力低、孢子增殖要求的温度不苛刻、囊合子和组织裂殖体大、裂殖体含的裂殖子数目多等优点,     

Wistar大鼠鼠龄、性别和脾脏对约氏疟原虫子孢子入侵和红外期发育的影

Wistar大鼠对约氏疟原虫Plasmodiumyoeliiyoelii子孢子较为敏感,是研究约氏疟原虫红外期较为理想的动物模型(王兴相等,1985)。但有关该动物的一些生理因素对子孢子入侵和红外期的发育影响所知甚少。本文用对比研究的方法观察了鼠龄、性别和脾脏对于孢子入侵和红外期发育的影响,以便更好地利用该鼠疟模型进行红外期生物学特性的研究。材料和方法约氏疟原虫BY265株每周血传一次,每5周蚊传一次,保种于昆明株小鼠体内。斯氏按蚊(An.stephensi)成蚊羽化后3天用于吸血感染,感染后置于24±1℃、RH80±10%温室内饲养,第14天按Pachecoetal(1979)…     

鼠疟原虫蚊期配子生殖的体外培养——在Eagle MEM培养基中发育的观察

为预防疟疾,开展疟原虫生物学、免疫学等方面的研究,从而设想建立疟原虫蚊期(配子生殖、孢子增殖)的体外培养系统。有关鼠疟原虫蚊期配子生殖的体外培养,国内外曾有不少的报道。近年来,国内曾用多种培养基对离体培养鼠动合子进行了初步观察;同时又在鼠疟动合子的形成和离体培养方法上进行了研究;国外学者罗萨利斯-龙奎尔(Rosales-Ronquillo)等在使用含斯氏按蚊细胞原代培养物的Eagle MEM.培养基和鲦鱼上皮细胞系Eagle MEM培养基对离体培养伯氏疟原虫的动合子进行了活体观察;斯皮尔(Speer)也使用了含该种蚊细胞的Eagle MEM培基进行鼠疟     

共聚焦激光扫描显微镜对约氏疟原虫卵囊、子孢子胞内Ca~(2 )的检测方法研究

本文报告建立用共聚焦激光扫描显微镜 (CLSM)观察约氏疟原虫卵囊、子孢子胞内游离Ca2 的分布和实验检测方法。以荧光染料Fluo 3作胞内Ca2 指示剂 ,结果显示 3μ、 4μmol/LFluo 3/Am同时加入 1μl/ml 2 5 %PluronicF 12 7在 37℃恒温下 ,分别孵育分离的约氏疟原虫子孢子、卵囊 6 0min即可达到最佳的负载效果。Fluo 3/Am浓度的提高和孵育时间延长只能增加背景染色 ,若降低孵育浓度和缩短孵育时间则难于达到最佳的负载效果。子孢子胞内游离Ca2 分布均匀 ;而卵囊内游离Ca2 分布不均匀 ,成块状分布 ,囊壁无荧光。研究表明应用Fluo 3/AM和PluronicF 12 7结合CLSM技术是研究疟原虫卵囊、子孢子胞浆内游离Ca2 的准确、灵敏的方法之一     

约氏疟原虫蚊期体外培养：动合子和动合子形成的扫描电镜观察

为了开展疟疾防治以及疟原虫生物学的研究,进一步了解在体外培养中疟原虫的发育规律、形态结构等生物学特性,我们于1985年对离体培养的约氏疟原虫约氏亚种动合子和动合子形成进行了扫描电镜的观察。 材料和方法 约氏疟原虫约氏亚种(Plasmalium yoelii yoelii)用血传和蚊传保种。在昆明株小鼠(KM/AMS)体内多次血传做为供血鼠。C_(57)6JB/ax 小鼠保种。定期感染斯氏按蚊(Anpheles stephensis)MEM     

鼠疟原虫动合子体外培养及其生物学活性的研究

体外形成的动合子能否感染蚊媒并继续在蚊体内发育是评价体外形成动合子发育成熟的重要指标。它关系到动合子-卵囊阶段的体外培养和整个蚊期疟原虫的培养。由于体外形成动合子的培养物中含有大量各阶段的疟原虫,对检验体外形成动合子的生物活性造成一定的困难。为此我们对约氏疟原虫动合子进行培养和分离,并检测了体外形成动合子的生物活性。     

Mechanism of escape of exoerythrocytic forms (EEF) of malaria parasites from the inhibitory effects of interferon-gamma

We have studied the mechanism of inhibition by interferon-gamma (IFN-gamma) of the development of exoerythrocytic forms (EEF) of Plasmodium berghei in the livers of rats. At the time corresponding to the maximum development of EEF (44 hr after injection of sporozoites), the livers of the IFN-gamma-treated rats contained less parasite DNA as compared with controls. Twenty-four to 72 hr later, the livers of both groups of animals were free of parasites; that is, IFN-gamma treatment does not delay the development of the EEF. The decrease in parasite DNA observed in the IFN-gamma-treated rats was due to a diminution in the number, but not the size, of EEF. It appears, therefore, that treatment with the lymphokine either destroys the parasites or does not affect their replication. To study the mechanism of resistance to IFN-gamma of a small population of EEF, we subjected the parasites to four cycles of selection by IFN-gamma. The parasites from the "selected" and "nonselected" populations were equally susceptible to inhibition by IFN-gamma, indicating that the escape from IFN-gamma activity is not inherited.     

Primary cultured murine hepatocytes but not hepatoma cells regulate the cell number through density-dependent cell death

The mechanisms by which hepatocytes regulate their cell numbers in culture have been examined. We found that when murine hepatocytes were cultured at an overconfluent stage, the number of viable cells were reduced to that of the confluent stage 48 h later by cell death. Cell death was accompanied by LDH release, and it was observed only in primary cultured hepatocytes but not in hepatoma cells. Genomic DNA analysis using electrophoresis showed that DNA fragmentation, a biochemical hallmark of apoptosis, was induced in superconfluent cultures of hepatocytes in a cell-density-dependent fashion, but not in pre-confluent cells. DNA fragmentation was rapidly induced 2 h after the beginning of the in vitro culture and continued up to 24 h later. Flow cytometry analysis demonstrated that the nuclei from the hepatocytes in a high density culture were condensed and that the DNA content was reduced. These data suggest that the mechanism of cell death is apoptosis. The DNA fragmentation seen in the high density hepatocyte culture was not observed in hepatoma cell lines. Moreover, apoptosis was induced in hepatocytes of MRL/lpr mice, suggesting that the Fas antigen was not involved in the apoptotic process. Apoptosis was inhibited by a protein synthesis inhibitor, cycloheximide, and by a calmodulin antagonist, W-7. Taken together, the results indicate that high density culture of murine hepatocytes though not hepatoma cells regulate their cell numbers by an apoptotic mechanism. The apoptosis is dependent on de novo protein synthesis and intracellular calcium metabolism.     

Human brown adipose cells in culture

Brown adipose tissue (BAT), obtained from the axillary and perirenal regions of newborns 24-48 h after death, was digested with collagenase and the free cells were cultured. Only the cultures of cells from tissue obtained later than 24 h post mortem were successful. These cells grew slowly to reach confluence. Their typical mitochondria gradually disappeared, being replaced by untypical mitochondria. After confluence, the cells accumulated large amounts of lipid in non-coalescent multivacuolar depots. This model can be useful for the study of the metabolic and morphological features of human brown fat cells.     

Interferon-gamma inhibits the intrahepatocytic development of malaria parasites in vitro

In this study, we examined the activity of recombinant interferon (IFN)-gamma against Plasmodium berghei exoerythrocytic forms (EEF) grown in vitro within the highly differentiated human hepatoma cell line HEPG2. We assayed the effect of IFN-gamma on parasite growth by DNA hybridization using a P. berghei specific DNA probe. The specific activity of IFN-gamma against EEF is very high, and depends upon the time of lymphokine addition. When IFN-gamma is added to HEPG2 cells containing intracellular EEF, 6 hr after sporozoite invasion, parasite DNA replication is inhibited by approximately 75% at 10(3) U/ml and 50% at 1 U/ml. This treatment can either abolish or greatly reduce the infectivity of EEF for mice. When added earlier, 3 hr after completion of sporozoite invasion, IFN-gamma inhibits parasite replication to an even greater degree. The highest levels of inhibition were obtained when IFN-gamma was added 6 hr prior to sporozoite invasion (100% inhibition at 10(2) U/ml, approximately 55% inhibition at 0.1 U/ml, and 17% inhibition at 0.001 U/ml). We found that HEPG2 cells express approximately 44,000 surface receptors for IFN-gamma. These data are consistent with the view that IFN-gamma exerts its antimalarial activity by binding to surface receptors on hepatocytes and inducing intracellular changes unfavorable for parasite development. Tryptophan starvation does not appear to be involved in this process. These findings also support the idea that IFN-gamma, released from immune T cells upon encountering sporozoite antigen, may be an important effector mechanism in sterile immunity to sporozoite challenge.     

The expression of hetero-organic antigens of kidney origin on the surfaces of cultured rat hepatocytes under the influence of the narrow-band fractions of non-histone chromosomal proteins]

Narrow fractions of nonhistone chromosomal proteins (NHCP) eluted with 0.4-0.5 M NaCl from the phosphocellulose column stimulate expression of hetero-organic antigens of kidney origin on the membrane of intact hepatocytes cultured in suspension. These fractions of NHCP were isolated from the intact rats kidney, from cells of hepatoma 27 and Zajdela hepatoma, and from the carcinogenic liver after a single diethylnirozamine injection. The membrane hetero-organic antigens were identified by means of indirect immunofluorescence using specific immune serum.     

大鼠肝癌细胞系的体外培养、纯化及辐照效应

用二乙基亚硝胺（ＤＥＮ）诱发大鼠肝癌,取肝癌白色结节,０．２５％胰酶消化,ＲＰＭＩ—１６４０培养基建系成功,共获１３系肝癌细胞系,经反复传代（１０代以上）,细胞系均以肝实质瘤细胞和胆管上皮癌细胞为主,另外夹杂少量成纤维细胞。用ＰＨ７．２的ＰＢＳ冲洗、７５％酒精消毒流式细胞仪（ＦＣＭ）后,纯化该细胞来．收集肝实质癌细胞系,用６０Ｃｏγ射线辐照,剂量为８００Ｒａｄ和１０００Ｒａｄ,结果８００Ｒａｄ剂量使肝实质癌细胞生长受到明显抑制,细胞传代时间延长一倍,１０００Ｒａｄ剂量使细胞生长停止,不能再行传代。     

Antigenic divergence in a primary rat hepatocyte culture after exposure to the hepatic carcinogen N-diethylnitrosamine

Using the indirect immunofluorescence method, the appearance of membrane hetero-organic antigens of kidney origin associated with the Zajdela hepatoma cells was observed on the surface of cells of the rat liver primary culture following a single hepatocarcinogen N-diethylnitrosamine (DENA) treatment before and after explantation. A correlation of antigenic alterations after a single DENA treatment in vivo and in vitro was discovered. No antigens under investigation were discovered in cultured hepatocytes of intact adult rats.     

Expression of calcium-binding protein regucalcin mRNA in hepatoma cells

Whether the gene expression of hepatic Ca²⁺-binding protein regucalcin is altered in hepatomas was investigated. The change in regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin complementary DNA (0.9 kb). Rat hepatoma was induced by continuous feeding of basal diet containing 0.06% 3-methyl-4-dimethylaminoazobenzene (3-Me-DAB). After 35 weeks feeding, rats were sacrificed, and the non-tumorous and tumorous tissues of the livers were removed. In individual rats, the regucalcin mRNA levels in the tumorous tissues were generally decreased in comparison with that of the non-tumorous tissues of the chemical-fed rats, although the chemical administration might decrease the mRNA expression in normal rat liver, suggesting that the chemical administration causes a suppresive effect on the mRNA expression. When the genomic DNA extracted from the liver tumorous tissues was digested with restriction enzymes (EcoRI, BamHI and HindIII) and analyzed by Southern blotting, no rear-ranged band was found in the regucalcin gene from the hepatoma. Interestingly, in the transplantable Morris hepatoma cells, the regucalcin mRNA was markedly expressed, while the albumin mRNA was expressed only slightly. The present study demonstrates that regucalcin mRNA is clearly expressed in the transformed cells (Morris hepatoma cells).     

Progressive loss in vitro immune response with tumor growth.

Peripheral blood lymphocytes from rats carrying a transplantable hepatoma were cultured in the presence of phytohemagglutinin (PHA), concanavalin A (ConA) or dextran sulfate (DS) at various times after tumor cell inoculation or after its surgical removal. Mitogen-induced lymphocyte transformation, measured by tritiated thymidine incorporation, declined as the tumor size increased, especially when cells were cultured in autologous serum. The response to PHA and ConA declined prior to the response to DS. This inhibition could not be removed by extensive washing of the cells, alteration of serum concentration, time of incubation or mitogen dose. Culture for 24 hr prior to the addition of high doses of mitogen resulted in partial restoration of the PHA and ConA, but not DS, responses. Previously inhibited responses also returned when the tumor was surgically removed. Spleen cells from animals with large tumors were also inhibited.