Spectrophotometric assay for ornithine decarboxylase

A rapid and sensitive spectrophotometric assay for ornithine decarboxylase is described. It is based on the observation that the product of ornithine decarboxylase, putrescine, reacts with 2,4,6-trinitrobenzenesulfonic acid to give a colored product soluble in 1-pentanol whereas ornithine does not. The amount of putrescine produced by the enzyme was determined by measuring the absorbance of the 1-pentanol extract of the reaction mixture at 420 nm, and by comparing the results to those obtained by the trapping of 14CO2 and by HPLC assays. The three assays were found to be equivalent in sensitivity, with the spectrophotometric assay having the advantages of being relatively rapid, requiring only common laboratory equipment, and not requiring the use of radioactive isotopes.     

Rat ventral prostate as an independent source of inhibin-like material

Castration had no effect on prostatic inhibin-like activity as compared to normal controls. Consequent upon castration there is a significant reduction in the inhibin content of the ventral prostate on a per gland basis. However, when expressed as a function of protein content, there is no change. The data suggest that the very same epithelial cells which under the influence of androgen carry out the characteristic exocrine secretory activity are responsible for the synthesis and secretion of inhibin-like material.     

Histopathology and cell culture characteristics of liver cells from grc − and grc + rats given diethylnitrosamine

The histopathological response and cell culture characteristics of liver cells from the R16 (grc ^–) strain of rats, which carries an MHC-linked deletion, were examined one week after a single intraperitoneal injection of 200 mg/ kg body weight diethylnitrosamine (DEN) and were compared with the response of liver cells from wild type (grc+) rats. The DEN exposure induced hydropicl vacuolar changes in the parenchymal cells and a limited proliferation of oval cells in the periportal areas of the livers of both grc+ and grc rats. Primary culture of collagenase-digested livers consisted of parenchymal, bile ductular and oval-related cells as determined by cell-specific immunohistochemistry. Subpassaged cells from grc+ rats exhibited oval cell ultrastructural morphology, inducible histochemical staining for gammaglutamyl transpeptidase (GGT), and DEN-associated onset of anchorage-independent growth. Primary cultures of liver cells from R16 rats consistently failed to form cell strains upon subpassage.Abbreviations DEN diethylnitrosamine - grc growth and reproduction complex - GGT gamma-glutamyl transpeptidase - MHC major histocompatibility complex     

Post-castration rebound of an androgen regulated prostatic gene

Summary After castration, the rat dorsolateral prostate M-40 mRNA initially decreased then rebounded to precastrated levels. The cellular site of M-40 expression and its renewed expression after castration was defined by in situ hybridization histochemistry. In situ hybridization with either a ³²P-labeled or biotin-labeled M-40 cDNA probe demonstrated that M-40 mRNA levels were higher in the lateral than dorsal prostate. A second androgen regulated gene, RWB, also was highly expressed in the lateral prostate. The biotinylated cDNA probes provided microscopic resolution of the expressing cells, revealing two distinct morphologies of lateral epithelium which expressed both the M-40 and RWB mRNA. These morphologies appeared in ducts which contained either epithelial cell sheets that were highly convoluted or thinner epithelial cells with a minimal degree of convolution. The RWB mRNA decreased in both cell populations in response to androgen withdrawal. The decline and reappearance of M-40 mRNA also appeared in both epithelial cell types. These data demonstrated that after castration the M-40 mRNA initially decreased as expected for an androgen sensitive gene and then progressed to a fully inducible state. The mechanism of this progression remains to be elucidated.     

Serum copper,zinc levels,and copper

Serum copper and zinc levels were determined in 20 healthy women and in 100 women with gynecological tumors. Malignant and benign tumor cases were separated according to their postoperative, histopathological examinations. The stages of malignant and benign tumors were also established histologically. Seventy benign and 30 malignant genital tumors (carcinoma of cervix in situ, cervix, ovary endometrium, and vulva) of the patients were differentiated histopathologically. The serum Cu/Zn ratios of patients were increased significantly from the control group (0.32±0.35) to the benign group (1.22±0.63) and from the benign group to the malignant group (2.24±1.03). Nine of 30 malignant cases were determined as false negative (30%) and 15 of 70 benign cases were determined as false positive (14.2%) according to the serum Cu/Zn ratios of patients. Serum copper levels of 30 malignant and 10 benign tumor cases showed linear correlation with serum ceruloplasmin values.     

Substance P analogues function as bombesin receptor antagonists and inhibit small cell lung cancer clonal growth

Human small cell lung cancer (SCLC) produces and secretes BN/GRP (bombesin/gastrin releasing peptide). Because BN stimulates the growth of SCLC cells and these cells have receptors for BN-like peptides, it is important to define agents which disrupt this self-promoting autocrine growth cycle. Here, substance P analogues were evaluated as BN receptor antagonists using SCLC cell lines. (D-Arg¹, D-Pro², D-Trp^7,9, Leu¹¹) substance P [(APTTL)SP] was one of the more potent analogues tested in inhibiting BN-like peptide receptor binding with an IC₅₀ value of 1 μM. Micromolar concentrations of (APTTL)SP antagonized BN receptor mediated elevation of cytosolic Ca²⁺ levels and decreased the colony formation in soft agarose. These data suggest that SP analogues function as SCLC BN receptor antagonists and may be useful in disrupting the autocrine growth function of BN-like peptides.     

区别人小细胞肺癌和非小细胞肺癌的LSC系列单克隆抗体(简报)

人小细胞肺癌的发病率虽不及非小细胞肺癌,但其五年生存率却相对低得多,这两种细胞类型不仅在病理类型上表现不同,在许多其它性质上也表现不同。小细胞肺癌是一种异质性疾病,它由几种形态不同的瘤细胞组成,包括非小细胞肺癌在内;它易早期转移,能在肝、脑和骨髓中繁殖,具有L-Dopa胱羧酶,神经原特异的烯醇化酶(enolase),能合成神经递质和多肽激素蛙皮肽等特性。目前已有关于小细胞肺癌的单克隆抗体的报道,我们采用美国N I H建立的小细胞肺癌细胞株SH-77作免疫原,目前尚未见有关抗该细胞株的单克隆抗体的报道,现将我们制备的三个单抗体及其初步特异性鉴定结果简报如下     

钙调素抑制剂——三氟拉嗪对肿瘤细胞增殖和微管组装的影响

本文用钙调素抑制剂——三氟拉嗪处理人胃癌MGC-803细胞,用免疫荧光细胞化学方法,放射免疫法和速流荧光分析等方法研究了钙调素对细胞增殖,环核苷酸代谢及微管组装,有丝分裂等细胞功能的调节作用。实验结果表明,TFP明显地抑制了人胃癌细胞的增殖,这种抑制增殖的作用,具有剂量和时间依赖关系,细胞群体中G_1期细胞增多,S期细胞下降,DNA合成明显地受到抑制。TFP处理的胃癌细胞仅在短时间内(5'-30')cAMP含量升高,cGMP浓度降低,cAMP/ ??cGMP比值比对照组高4.4倍,但此后环核苷酸含量又很快恢复到对照组水平。本实验还观察到TFP处理后的MGC-803细胞胞质铺展,细胞形态的改变与胞质微管的分布有密切联系,实验结果表明TFP加强了人胃癌细胞MTOC对微管的组装能力,使微管分布得到恢复,微管纤维呈放射状延伸到细胞边缘,充满胞浆,使细胞呈现出展平的多边形,趋向于正常上皮细胞形态的变化,本实验结果表明TFP抑制癌细胞增殖及使微管组装加强可能是通过对CaM活性的抑制作用。此结果有助于说明转化细胞内钙调素的变化,可能是与转化细胞增殖失控和胞质微管消退有关。     

Cell surface heparan sulfate proteoglycan and the neoplastic phenotype

Cell surface proteoglycans are strategically positioned to regulate interactions between cells and their surrounding environment. Such interactions play key roles in several biological processes, such as cell recognition, adhesion, migration, and growth. These biological functions are in turn necessary for the maintenance of differentiated phenotype and for normal and neoplastic development. There is ample evidence that a special type of proteoglycan bearing heparan sulfate side chains is localized at the cell surface in a variety of epithelial and mesenchymal cells. This molecule exhibits selective patterns of reactivity with various constituents of the extracellular matrix and plasma membrane, and can act as growth modulator or as a receptor. Certainly, during cell division, membrane constituents undergo profound rearrangement, and proteoglycans may be intimately involved in such processes. The present work will focus on recent advances in our understanding of these complex macromolecules and will attempt to elucidate the biosynthesis, the structural diversity, the modes of cell surface association, and the turnover of heparan sulfate proteoglycans in various cell systems. It will then review the multiple proposed roles of this molecule, with particular emphasis on the binding properties and the interactions with various intracellular and extracellular elements. Finally, it will focus on the alterations associated with the neoplastic phenotype and will discuss the possible consequences that heparan sulfate may have on the growth of normal and transformed cells.     

DNA拓扑异构酶Ⅰ生物学活性的比较研究

测定了3T3细胞、人和大鼠一些组织中DNA拓扑异构酶Ⅰ的活性;估计了核酸内切酶对拓扑酶Ⅰ松弛活性测定的干扰程度;发现增殖组织全细胞抽提液中酶比活高于正常分化组织,而且在异常增殖组织中酶比活的增高更为显著。