涎腺腺样囊性癌细胞蛋白激酶C的活性阻抑对其侵袭能力的影响

用蛋白激酶Ｃ（ＰＫＣ） 抑制剂Ｈ７ 作用于人涎腺腺样囊性癌ＳＡＣＣ８３ 系, 利用扫描电镜观察对人羊膜基底膜侵袭能力的影响。癌细胞接种于羊膜基底膜表面４８－ ７２ 小时后, 在扫描电镜下可以观察到对照组癌细胞侵袭现象, 侵袭的细胞伸出丝状伪足且侵入基底膜内, 伪足周围的基底膜断裂和被溶解, 而实验组癌细胞侵袭现象很难发现。细胞附于基底膜表面, 细胞表面较光滑且无明显伪足伸出, 基底膜无明显受损改变。实验结果表明, 降低涎腺腺样囊性癌细胞的ＰＫＣ活性可明显降低其侵袭能力, ＰＫＣ与涎腺腺样囊性癌的侵袭能力有密切的关系     

封闭群草原兔尾鼠肝脏和胰腺的组织学观察

首次对封闭群草原兔尾鼠的肝脏、胰腺进行了组织学观察,结果表明：1．草原兔尾鼠的肝脏纤维组织极少,肝小叶间界限不明显;部分中央静脉周围可见少量毛细胆管;门管区较少,分布不均匀,其静脉形状不规则、腔大,胆管及动脉则较小。2．胰腺分叶清晰,腺泡细胞较大,胞浆多呈嗜酸染色;小叶中部腺泡着色较深,外侧腺泡着色较浅;胰岛大小不等,细胞排列呈不规则索状,光镜下未见特殊改变。     

黄花补血草叶片盐腺的发育解剖学研究

利用扫描电镜和石蜡切片法对黄花补血草叶片进行解剖学研究,观察叶片营养器官中盐腺的分布、密度、结构及发育过程。结果表明:黄花补血草叶片上、下表皮有大量的盐腺分布,且下表皮的盐腺密度比上表皮的多,盐腺周围有7～9个表皮细胞呈辐射状排列;盐腺的成熟结构由12个细胞构成,中央有4个分泌细胞,每个分泌细胞都有一个明显的分泌孔,是盐分泌出的通道;分泌细胞外侧伴有4个弧形的毗邻细胞围成一圈;盐腺内部靠近叶肉细胞处有4个收集细胞。研究认为,黄花补血草盐腺由一个表皮原始细胞发育而成,分别经历单细胞时期、2细胞时期、4细胞时期、8细胞时期和12细胞时期的不同发育阶段。     

田鳖消化系统的组织学与组织化学研究

田鳖的食道细长,在前端附近发生一分枝,成为嗉囊。贲门瓣十分发达,几乎全部由前肠的上皮细胞构成。中肠分为三部分:中肠前部呈囊状,壁厚;中肠中部最为细长,其上皮形成四十大形的纵褶,突入腔内;中肠后部细短,上皮无此种纵褶。中肠三部分的上皮细胞均行局泌,胞窝内再生细胞甚多。直肠分为较细长的前部与较粗短的后部,后者又生一大形的侧突,这三部分内都具有十分发达的直肠垫。 田鳖的唾腺高度分化,由大主腺,小主腺及副腺各一对组成,因此与异翅亚目显角类。不同,而与同翅亚目相似。大小主腺均呈葡萄状,由许多腺囊组成。大主腺前端的一对球状部分呈乳白色,其分泌物中含有脂蛋白与中性粘多糖或粘朊,而大主腺本部与整个小主腺的半透明腺囊则仅分泌中性粘多糖或粘朊。植食性半翅目昆虫唾腺分泌物中十分普遍的酸性粘多糖,在田鳖中却未测得。副腺呈管状,其前端透明部分及后端半透明部分的细胞染色性质不同,但由于副腺的水状分泌物在切片中无法保存,因此未测得其组成成分。     

猕猴鳞状细胞癌一例报告

1988年7月8日我们见1只15岁雌性病猕猴(Macaca mulatta)处死后,尸检见左侧颊囊粘膜面淡红色0.5匣米大溃疡一个,溃疡底部可见一个8×3×1.5厘米大肿块及数个小结节。肿瘤紧贴于下頜骨与舌下组织无明显分界,中央坏死。镜检见溃疡处和其他结节的组织结构相同,癌细胞呈多边形或不规则,胞浆丰富,核深染、异形性或分裂。癌细胞排列成巢状或片状,个别癌细胞角化或形成角化珠。诊断为鳞状细胞癌(原发于颊囊粘膜)。     

不同年龄与不同时期林麝香腺组织结构观察

本研究旨在探究林麝(Moschus berezovskii)在不同年龄和泌香期与非泌香期香腺的组织结构变化,为深入研究林麝香腺发育和麝香分泌机制提供基础资料。收集6只雄性林麝的香腺组织,包括泌香期2岁龄林麝1例,非泌香期6月龄、2岁龄、4岁龄、6岁龄和8岁龄林麝各1例,采用大体解剖、石蜡切片及常规H.E染色技术,对香腺的形态、组织特征及腺泡直径进行了比较分析。结果显示,林麝香腺位于腹部阴囊与腹脐之间,与阴囊的距离约为4.5 cm。根据功能,香腺可划分为香囊部和腺体部。负责分泌麝香液的腺体组织为肉眼可见的白色颗粒,嵌入腺体部肌层深处并环绕香囊颈分布。6月龄林麝香腺已具有成熟腺体结构,但腺上皮仍处于休止状态;成年林麝香腺的腺泡则增大且数量增多。成年林麝泌香期腺泡被挤压成团状分布,上皮游离面破碎不整,腺泡腔内含有大量明显的颗粒状分泌物与细胞碎屑混合堆积;非泌香期腺泡直径显著大于泌香期(P < 0.01),2岁林麝腺泡表现为紧密排列的椭球形,而4岁及以上的腺泡则呈不规则团状分布,腔内可见颗粒物,且4岁、6岁和8岁的腺泡直径无显著差异(P > 0.05)。林麝香腺组织结构的变化反映了泌香能力与生长阶段的关系。     

四种补血草属植物叶片泌盐结构的扫描电镜观察

利用扫描电镜技术,对4种补血草属植物大叶补血草（Limonium gmelinii (Willd.) Kuntze）、耳叶补血草（Limoniu otolepis (Schrenk) Kuntze）、繁枝补血草（Limonium myrianthum (Schrenk) Kuntze）和簇枝补血草（Limonium auream）的叶表面进行了研究,以探讨植物微形态结构与生态环境的关系。结果表明,这4种植物的上下表皮都分布有盐腺,且上表皮的盐腺密度大于下表皮,盐腺的基本结构相同,多由20个细胞构成,其中4个分泌细胞顶端的角质层中央有一小孔,植物体靠盐腺的泌盐孔泌盐。但4种植物在盐腺的密度、盐腺的大小、盐腺与周围表皮细胞的位置等方面存在差异。植物在对盐碱生境的长期适应过程中,促使其强烈地分化出泌盐结构,因而,具有明显的生态适应性。     

埃塞俄比亚塔纳湖鲤科鱼类体内亚美尼亚许氏绦虫Khawia armeniaca (Cholodkovsky, 1915) Shulman, 1958 (绦虫纲: 鲤蠢目) 的形态鉴定

在埃塞俄比亚境内塔纳湖中发现了1种寄生于鲤科鱼类: 间魮(Labeobarbus intermedius)和Labeobarbus tsanensis体内的许氏绦虫, 经形态学鉴定其为亚美尼亚许氏绦虫Khawia armeniaca (Cholodkovsky, 1915)(绦虫纲: 鲤蠢目)。该绦虫鉴别特征为头节呈半球状, 边缘光滑, 无皱褶; 睾丸分布区域从虫体中部至阴茎囊之前; 卵巢前卵黄腺分布于虫体中后部至阴茎囊前部区域, 少数排列在阴茎囊之后; 子宫起始于阴茎囊后方弯曲环绕直至卵巢后部区域, 有少许卵黄腺排列在子宫和卵巢的两侧。此外, K. armeniaca卵巢呈滤泡状或蝴蝶状, 雌雄生殖孔分离但彼此距离很近, 开口于体表并形成同一生殖腔, 且雄性生殖孔位于雌性生殖孔前方。卵巢后卵黄腺数目少于100个, 分布于虫体末端, 卵黄腺距离卵巢后翼较远, 部分样品内卵黄腺接近卵巢后翼。     

白胸苦恶鸟消化管的组织学观察

采用石蜡切片技术对白胸苦恶鸟(Amaurornis phoenicurus)的消化道进行了组织学观察.结果表明,食管皱襞发达,黏膜上皮为复层扁平上皮,食管腺发达,颈段多于胸段,黏膜肌层为一层纵肌,厚约0.06 ～0.26 mm.肌层为一层厚约0.19～0.27mm的环肌.腺胃被覆单层柱状上皮,固有层内有单管腺和复管腺两种腺体,单管腺仅深约0.11 ～0.20 mm;复管腺厚约1.19～1.26 mm,占管壁的77.8％ ～80.4％.肌胃的类角质层发达,厚约0.16～0.24 mm.肌胃腺呈管状,与类角质层突起形成皱襞.肌层发达,由内环外纵两层平滑肌构成.肠绒毛无分支和中央乳糜管,十二指肠绒毛长而密集,空肠绒毛呈细长指状,直肠绒毛长且呈叶状.十二指肠与直肠肠绒毛内有大量致密淋巴小结,盲肠绒毛短,肠腺少.     

苦瓜籽蛋白MAP30的聚乙二醇化学修饰及抗肿瘤活性研究

采用硫酸铵分级沉淀、SP-Sepharose FF离子交换层析和Blue Sepharose CL-6B亲和层析获得苦瓜蛋白MAP30;采用(mPEG)2-Lys-NHS修饰MAP30;对修饰后的MAP30-PEG结合物与MAP30的抗肿瘤活性进行了比较分析。结果发现:MAP30对多数肿瘤细胞株具有明显的抑制作用,而且抑制效果在一定范围内具有剂量和时效依赖关系。但是在相同条件下,MAP30对人正常胚肺二倍体细胞株WI-38的毒性极小。MAP30和MAP30-PEG结合物对小鼠黑色素瘤(B16)、人宫颈癌细胞(Hela)和人表皮癌细胞(A431)细胞均表现出抑制作用,且这种作用在一定范围内呈时效和量效依耐性。但在相同浓度下PEG-MAP30对小鼠黑色素瘤(B16)、人宫颈癌细胞(Hela)和人表皮癌细胞(A431)的抑制作用低于MAP30,约占65%～70%左右。     

Transfilter analysis of the inductive influence of proventricular mesenchyme on stomach epithelial differentiation of chick embryos

Summary To clarify the precise conditions under which chick embryonic proventricular mesenchyme can induce proventricular epithelial differentiation, transfilter experiments were carried out. Six-day proventricular epithelium formed glands and expressed pepsinogen when a Nucleopore filter with a pore size of more than 0.6 m, but not 0.2 m, was inserted between the epithelium and the proventricular mesenchyme. The larger the pore size of the filter, the more elongated the glands and the more pepsinogen was induced in the explants. The quail nuclear marker and scanning electron microscopy were used to examine penetration of mesenchymal cells through the Nuclepore filter. The filter of more than 0.2 m pore size allowed cell processes of mesenchymal cells to pass through. However, only the filter with a pore size of more than 0.6 m allowed actual migration of mesenchymal cells through the filter, and the larger the pore size of the filter, the more mesenchymal cells passed through. Under the same conditions 6-day and 4.5-day gizzard epithelium formed glands and expressed pepsinogen. These results indicate that a flow of diffusible substances through a Nuclepore filter and even direct contact of a few short cell processes of mesenchymal cells with epithelial cells are not sufficient for induction, and that direct contact of mesenchymal cell processes and/or mesenchymal cells with epithelial cells over a considerably wide area may be prerequisite for the induction.     

Localization of glycosidases in the wall of living cells from cultured Convolvulus arvensis tissue

Nine glycosidase activities were detected in isolated cell walls of cultured Convolvulus arvensis L. cells. Seven were also found in the cytoplasmic fraction. Optimal pH values were all in the acid region. The in vivo localization of some of these glycosidases was studied by assaying whole cells. Suspended cells hydrolysed the externally supplied substrates for -galactosidase (EC 3.2.1.22), -galactosidase (EC 3.2.1.23), -glucosidase (EC 3.2.1.21), -mannosidase (EC 3.2.1.24) and -xylosidase (EC 3.2.1.37). Since intracellular enzymes were latent or showed little leakage, the cells were regarded to be relatively intact. In the cases investigated, the apparent glycosidase activity values of whole cells corresponded to those of isolated cell walls. The pH-activity profiles were similar. The K_m values were identical indicating equal accessibility to substrate. The enzymes could be partially removed from the cells by strong salt solutions. The data are consistent with an in vivo cell wall localization of a number of glycosidases.Abbreviation PNP p-nitrophenyl     

Isolation of generative cells and their protoplasts from pollen ofLilium longiflorum

Summary Methods are described for the isolation of large quantities of generative cells and their protoplasts from the pollen ofLilium longiflorum. First, large numbers of pollen protoplasts were enzymatically isolated from immature pollen grains. When they were gently disrupted mechanically, the pollen contents including spindle-shaped generative cells were released. The generative cells were separated from other structures by Percoll density gradient centrifugation. They were nearly spherical, but had a callosic cell wall. The isolated generative cells were then re-treated in enzyme solution to yield authentic protoplasts. The generative cell protoplasts, gametoplasts, were uniform in size and contained a condensed haploid nucleus with relatively little cytoplasm.     

Surface morphology of taste buds in catfish barbels

Summary External taste buds abound on barbels of the adult catfish Corydoras arcuatus. When examined by scanning electron microscopy, they are visualized as a series of punctate, conical elevations projecting from the general surface epithelium. All taste buds were found to be of one type. Both their external and internal surface features could be clearly elucidated on intact barbels and in barbels fractured transversely at various positions along their length. An extensive nerve terminal network penetrates the base of each taste bud. Two populations of elongated cells bearing prominent microvilli project through the central pore at the tip of each bud. One set of microvilli is thicker, longer and more club-shaped than its counterpart. While both are randomly distributed within each central pore, the small, short microvilli appear to outnumber the larger ones. A third population of cells, devoid of any apical microvilli, was also seen in some of the taste buds examined internally. These cells do not project to the external surface and are interpreted as basal cells described in previous light and transmission electron microscope studies of taste buds in other vertebrate species. The functional significance of some of these morphological findings is discussed.Supported by grants from the Medical Research Council of Canada and the Muscular Dystrophy Association of CanadaThe excellent technical assistance of Mr. F.T. McConnell is gratefully acknowledged     

Pharmacological Manipulation of the Akt Signaling Pathway Regulates Myxoma Virus Replication and Tropism in Human Cancer Cells

Viruses have evolved an assortment of mechanisms for regulating the Akt signaling pathway to establish a cellular environment more favorable for viral replication. Myxoma virus (MYXV) is a rabbit-specific poxvirus that encodes many immunomodulatory factors, including an ankyrin repeat-containing host range protein termed M-T5 that functions to regulate tropism of MYXV for rabbit lymphocytes and certain human cancer cells. MYXV permissiveness in these human cancer cells is dependent upon the direct interaction between M-T5 and Akt, which has been shown to induce the kinase activity of Akt. In this study, an array of compounds that selectively manipulate Akt signaling was screened and we show that only a subset of Akt inhibitors significantly decreased the ability of MYXV to replicate in previously permissive human cancer cells. Furthermore, reduced viral replication efficiency was correlated with lower levels of phosphorylated Akt. In contrast, the PP2A-specific phosphatase inhibitor okadaic acid promoted increased Akt kinase activation and rescued MYXV replication in human cancer cells that did not previously support viral replication. Finally, phosphorylation of Akt at residue Thr308 was shown to dictate the physical interaction between Akt and M-T5, which then leads to phosphorylation of Ser473 and permits productive MYXV replication in these human cancer cells. The results of this study further characterize the mechanism by which M-T5 exploits the Akt signaling cascade and affirms this interaction as a major tropism determinant that regulates the replication efficiency of MYXV in human cancer cells.Following viral infection, substantial alterations in cellular physiology often lead to modification of various cellular pathways critical to the success of viral replication. The demands for energy, nutrients, and macromolecular synthesis that accompany viral replication can be substantial; thus, many viruses have evolved elaborate strategies for hijacking key cellular signaling networks necessary to support their demands (9). By the same token, antiviral pathways activated by the virus infection may also need to be blocked or subverted to ensure successful virus replication. Poxviruses possess large double-stranded DNA (dsDNA) genomes that encode multiple gene products that specifically modify or debilitate the various host signaling responses of the infected cell (28). Many of the immunoregulatory factors expressed by poxviruses have been well characterized, and these factors include virokines, viroreceptors, signaling modulators, and inhibitors of various antiviral responses, such as initiation of apoptosis pathways and signaling by protective cytokines, like interferon and tumor necrosis factor (TNF) (42).Myxoma virus (MYXV) is a member of the Leporipoxvirus genus and exhibits a restricted pathogenesis that is limited to rabbits, primarily due to its specific immunomodulation of the immune system of leporids (48). In rabbits (Sylvilagus spp.) of the Americas, MYXV infection results in a benign infection, characterized by a cutaneous fibroma restricted to the site of inoculation (14); however, the same virus causes a rapid systemic and highly lethal infection called myxomatosis in European rabbits (Oryctolagus cuniculus) (15). Although MYXV has a narrow host range in nature and is pathogenic only to European rabbits, the tropism of MYXV has recently been extended to include human tumor cells in vitro (6, 47, 54, 57, 60) and in xenografted mice in vivo (24, 25, 61). The mechanisms that mediate MYXV tropism in human cancer cells are still being investigated, but one signaling requirement has been linked to the state of cellular Akt kinase activity (57). Human cancer cells (called type I) that exhibit high levels of endogenous phosphorylated Akt (Ser473 and Thr308) supported permissive MYXV replication, while cells with no detectable endogenous phosphorylated Akt, which were unaffected by the virus infection, were nonpermissive (type III). A unique subset of cancer cells (type II) were found to be permissive to wild-type MYXV but did not support MYXV replication following the deletion of the viral host range factor M-T5 (vMyxT5KO). These type II cells constitutively expressed only low levels of endogenous phosphorylated Akt (mostly at Thr308), but following infection with permissive MYXV, a significant increase in Akt phosphorylation (particularly at Ser473) was observed. In stark contrast, the endogenous levels of phosphorylated Akt remained essentially unchanged when type II cells were infected with the nonpermissive M-T5 knockout virus MYXV (vMyxT5KO) (57).The host range factor M-T5 is essential for MYXV replication in rabbit primary lymphocytes (RL-5 cells) and for virus pathogenesis in European rabbits (31). Structurally, M-T5 possesses seven ankyrin (ANK) repeats and a carboxyl-terminal PRANC (pox protein repeats of ankyrin C-terminal) motif, which closely resembles a cellular protein motif called the F-box domain (29). Interaction between M-T5 and components of the cellular SCF (Skp-cullin-F-box) ubiquitin ligase complex was shown to protect MYXV-infected cells from cell cycle arrest (19). In MYXV-infected type II human cancer cells, physical interaction between M-T5 and cellular Akt was shown to upregulate the kinase activity of Akt (57). In another study, M-T5 was shown to be functionally interchangeable with the host ANK repeat-containing protein PIKE-A, and activation of Akt by either PIKE-A or the viral M-T5 protein was sufficient to mediate MYXV permissiveness in type II human cancer cells (59). Similarly, addition of the immunosuppressant drug rapamycin was successful at rescuing vMyxT5KO replication in type II cells by upregulating Akt activation through the mTOR pathway (47). The critical role of Akt in the regulation of multiple biological processes makes Akt a central regulator of cellular signaling, and therefore, it is not surprising that many viruses have developed sophisticated strategies for manipulating the activation of Akt (9, 11).The serine/threonine kinase Akt (also called protein kinase B [PKB]) was initially discovered as the cellular homolog of the viral oncogene (v-Akt) carried by the AKT8 retrovirus isolated from a murine T-cell lymphoma (7, 20, 46). There are three isoforms found in mammals (Akt1, -2, and -3), encoded by separate genes but sharing over 80% amino acid sequence identity. Activation of Akt is predominantly dependent upon phosphoinositide 3-kinase (PI3K), which phosphorylates phosphoinositides (PIs) at the D3 position of the inositol ring to generate PI(3,4,5)P₃ (PIP₃). Akt possesses an N-terminal PH (pleckstrin homology) domain that binds PIP₃ to promote its translocation of the plasma membrane. Once localized at the membrane, Akt becomes phosphorylated at residue Thr308 in the activation loop by phosphoinositide-dependent kinase 1 (PDK1) and also within the carboxy terminus at residue Ser473 by mTORC2 (mammalian target of rapamycin complex 2) (2, 49, 50). Phosphorylation of both sites is necessary for full induction of Akt kinase activity. Akt is a key regulator of many important cellular functions, including cell survival, proliferation, glucose metabolism, and protein synthesis. In the majority of human cancer cells, the Akt pathway is either mutated or constitutively activated, contributing to cancer progression through both stimulation of cellular proliferation and inhibition of apoptosis (34, 55).In this study, we screened an array of Akt inhibitor compounds that selectively manipulate the Akt signaling network at some level and report that certain Akt inhibitors significantly blocked MYXV replication in previously permissive type I and II human cancer cells. An additional set of inhibitors selectively inhibited only the replication of MYXV deleted for M-T5 and did not modify the replicative ability of the parental wild-type virus. Furthermore, the decrease in viral replication efficiency was correlated with lower levels of phosphorylated Akt at residues Thr308 and Ser473. In contrast, certain PP2A-specific phosphatase inhibitors, such as okadaic acid, promoted increased Akt kinase activation and rescued MYXV replication in type III human cancer cells that did not previously support viral replication. Finally, we demonstrate that the hemi-phosphorylation of Akt at residue Thr308 dictates physical interaction between Akt and M-T5, which ultimately leads to productive MYXV replication in type II cancer cells. These studies show that activation of the Akt signaling cascade is essential for efficient MYXV replication in human cancer cells and further demonstrate the dynamic role by which M-T5 manipulates Akt signaling to establish a cellular environment more favorable for viral replication.     

Acridine orange fluorescence of mast cells as influenced by fixation

Summary The basic fluorochrome dye acridine orange was applied to different tissues of the rat for staining mast cells. This was performed under different fixation conditions in order to assess the effects of fixative fluids on the resulting fluorescent staining. Under the conditions described, acridine orange has constantly revealed mast cells in bright fluorescence in tissues where they are known to be present normally. The results are discussed in reference to each fixative used. But the method failed to show the mucosal mast cells in the stomach and duodenum. This is proposed as a new element for the further characterization of these cells.This work was supported by the Medical Research Council of Canada (Grant No. 2,236).The author is indebted to Mrs. H. Gonzalez for her skillful technical assistance.     

Aerenchyma tissue development and gas-pathway structure in root of Avicennia marina (Forsk.) Vierh.

The aerenchyma differentiation in cable roots, pneumatophores, anchor roots, and feeding roots of the mangrove plant, Avicennia marina (Verbenaceae) was analyzed using a light microscope and scanning electron microscope. In all types, cortex cells were arranged in longitudinal columns extending from the endodermis to the epidermis. No cells in the cortex had intercellular spaces at the root tip (0–150 m), and aerenchyma started developing at 200 m from the root apex. The aerenchyma formation was due to cell separation (schizogeny) rather than cell lysis. The cell separation occurred between the longitudinal cell columns, forming long intercellular spaces along the root axis. During aerenchyma formation, the cortex cells enlarged longitudinally by 1.8–3.9 times and widened horizontally by 2.2–2.9 times. As a result, the aerenchyma had a pronounced tubular structure that was radially long, elliptical or oval in cross section and that ran parallel to the root axis. The tube had tapering ends, as did vessel elements, although there were no perforated plates. The interconnection between neighboring tubes was made by abundant small pores or canals that were schizogenous intercellular spaces between the wall cells. All aerenchyma tubes in the root were interconnected by these small pores serving as a gas pathway.     

Large-Scale Purification of r28M: A Bispecific scFv Antibody Targeting Human Melanoma Produced in Transgenic Cattle

Background

30 years ago, the potential of bispecific antibodies to engage cytotoxic T cells for the lysis of cancer cells was discovered. Today a variety of bispecific antibodies against diverse cell surface structures have been developed, the majority of them produced in mammalian cell culture systems. Beside the r28M, described here, no such bispecific antibody is known to be expressed by transgenic livestock, although various biologicals for medical needs are already harvested—mostly from the milk—of these transgenics. In this study we investigated the large-scale purification and biological activity of the bispecific antibody r28M, expressed in the blood of transgenic cattle. This tandem single-chain variable fragment antibody is designed to target human CD28 and the melanoma/glioblastoma-associated cell surface chondroitin sulfate proteoglycan 4 (CSPG4).

Results

With the described optimized purification protocol an average yield of 30 mg enriched r28M fraction out of 2 liters bovine plasma could be obtained. Separation of this enriched fraction by size exclusion chromatography into monomers, dimers and aggregates and further testing regarding the biological activity revealed the monomer fraction as being the most appropriate one to continue working with. The detailed characterization of the antibody’s activity confirmed its high specificity to induce the killing of CSPG4 positive cells. In addition, first insights into tumor cell death pathways mediated by r28M-activated peripheral blood mononuclear cells were gained. In consideration of possible applications in vivo we also tested the effect of the addition of different excipients to r28M.

Conclusion

Summing up, we managed to purify monomeric r28M from bovine plasma in a large-scale preparation and could prove that its biological activity is unaffected and still highly specific and thus, might be applicable for the treatment of melanoma.     

Differentiation of epithelial cells in the mouse thymus

Summary The foetal and post-natal development of the mouse thymus was studied with the electron microscope paying particular attention to the differentiation of the epithelial cells. At about 13 days' gestation, the thymus was composed principally of undifferentiated epithelial cells and some lymphoblasts. The latter accumulated rapidly but did not show much evidence of mitotic activity until after the development of differentiated cortical epithelial cells which appeared during the 15th day of gestation. Further differentiation of epithelial cells did not occur until near term when medullary cystic epithelial cells appeared, and post-natally when small Hassall's corpuscles were developed. Undifferentiated and dividing epithelial cells were seen in the medulla and were present in all postnatal animals examined.This is publication number 1400 from the Walter & Eliza Hall Institute of Medical Research.The author is grateful to Prof. G. J. V. Nossal, Dr. J. F. A. P. Miller and Dr. P. J. Russell for their interest and assistance with various aspects of this study. Special thanks are due to Miss Mary Bravington for her skilled technical assistance. This investigation was supported by grants from the Jane Coffin Childs Memorial Fund for Medical Research and the National Health and Medical Research Council of Australia. The Electron Microscope Laboratory was equipped and supported by grants from the Australian Research Grants Committee, J. B. Were and Sons and the Potter Foundation.