Tumor incidence in Visna virus inoculated mice

Summary Mice (female Swiss albino) inoculated when newborn with Visna virus had tumors in 77% of cases when examined 8–12 months later. The tumors were mainly of the mammary carcinoma type. The tumor incidence in noninfected control animals was only 20%. In contrast, no increased incidence of tumors was observed among Visna virus-inoculated inbred mice (BALB/c, CBA and DBA) with low incidence of spontaneous mammary carcinoma.This study was supported by grant No. B75-16X-4511-01 of the Swedish Medical Research Council.     

Persistent and atypical lobules in the human breast may be precancerous.

Persistent human mammary lobules (PL) remaining after the menopause, and certain atypical lobules (ALA) are morphologically similar to the common preneoplastic hyperplastic alveolar nodule (HAN) of mice of strains having a high incidence of mammary carcinoma. This and other evidence suggest that like the HAN of mice human PL and ALA are precancerous.     

Persistent and atypical lobules in the human breast may be precancerous

Summary Persistent human mammary lobules (PL) remaining after the menopause, and certain atypical lobules (ALA) are morphologically similar to the common preneoplastic hyperplastic alveolar nodule (HAN) of mice of strains having a high incidence of mammary carcinoma. This and other evidence suggest that like the HAN of mice human PL and ALA are precancerous.This work was supported by a contract from the National Institutes of Health. PHS NOI-CB-43908, and funds from the Cancer Research Coordinating Committee, University of California.     

Inhibition de la cancérogenèse spontanée chez les souris R III et AkR par des implants de tissus cancéreux modifiés

Summary (1) After a 24-h passage in a rabbit, fragments of spontaneous isologous mammary carcinoma were implanted under the skin of young R III females. This procedure was found to prevent the appearance of spontaneous mammary tumours in a high percentage of these animals. The subsequent appearance of carcinoma was to be observed in only 23% of treated animals as compared with 51% in controls.(2) After a 24-h passage in a rabbit, fragments of leukotic isologous tissue, implanted subcutaneously in young AkR females, reduced subsequent spontaneous leukomogenesis from 85 to 38%.     

Molecular mechanisms of melatonin’s inhibitory actions on breast cancers

Melatonin is involved in many physiological functions and it plays an important role in many pathological processes as well. Melatonin has been shown to reduce the incidence of experimentally induced cancers and can significantly inhibit the growth of some human tumors, namely hormone-dependent cancers. The anticancer effects of melatonin have been observed in breast cancer, both in in vivo with models of chemically induced rat mammary tumors, and in vitro studies on human breast cancer cell lines. Melatonin acts at different physiological levels and its antitumoral properties are supported by a set of complex, different mechanisms of action, involving apoptosis activation, inhibition of proliferation, and cell differentiation.     

Isolation of a protease from the cell-free medium of in vitro cultured mammary carcinoma.

Trypsin-like protease with wide spectrum of enzymatic activities have been isolated from cell-free medium from in vivo cultured human mammary carcinoma cells, and from peripheral blood lymphocytes of patients with mammary carcinoma cultured in presence of cell-membrane carcinoma-associated glycoprotein.     

Isolation of a protease from the cell-free medium of in vitro cultured mammary carcinoma

Summary Trypsin-like protease with wide spectrum of enzymatic activities have been isolated from cell-free medium from in vitro cultured human mammary carcinoma cells, and from peripheral blood lymphocytes of patients with mammary carcinoma cultured in presence of cell-membrane carcinoma-associated glycoprotein.     

Alteration in the secretion of anterior pituitary hormones during dimethylbenzathracene induction of mammary tumors in rats]

In a sensitive strain of Rat (Sprague-Dawley) a deregulation of the secretion of some pituitary hormones was noted in the female during induction of mammary tumors by dimethylbenzanthracene administration. The deregulation occurred quickly and depended on the stage of the estrous cycle. It mainly consists of hyposecretion of gonadotropins. TSH and GH and of hypersecretion of prolactin.     

CT诊断甲状腺肿块18例临床分析

目的探讨甲状腺肿块的CT诊断价值。方法回顾分析18例甲状腺肿块的CT特征,并与手术病理对照。结果CT诊断18例甲状腺肿块与手术病理符合率的情况：（1）结节性甲状腺肿7例,诊断符合率71％（5／7）;（2）甲状腺腺瘤8例,诊断符合率63％（5／8）;（3）甲状腺癌3例,诊断符合率67％（2／3）。结论CT对甲状腺肿块的诊断虽然有很大价值,但是部分甲状腺肿块CT表现无特征性,定位诊断准确,定性诊断困难。     

Lipid peroxidation,low-level chemiluminescence and regulation of secretion in the mammary gland

In mammary explants of lactating mice, changes in the intensity of chemiluminescence (CL) were observed after the addition to the incubation medium of hormones and mediators that are involved in the regulation of secretion: oxytocin, acetylcholine, epinephrine and norepinephrine. A 15-min period of treatment with oxytocin, epinephrine or norepinephrine changed the level of thiobarbituric acid-reactive substances (TBARS). Two mammary explants, one of which was treated with oxytocin, acetylcholine, epinephrine or norepinephrine, were found to interact even when separated by a quartz glass wall. Analysis of the level of TBARS formation in these two explants showed that the observed interactions might be connected with light emission resulting from lipid peroxidation (LP) processes. The possible role of LP and low-level CL in the regulation of mammary gland secretion is discussed.     

Ultrastructural aspects of the cell fusion induced by Visna virus on sheep choroid plexus cell in culture]

Sheep choroid plexus cells infected with low multiplicities of infection of Visna Virus were stellate and had long and thin processes containing filaments and forming cytoplasmic bridges between adjacent cells. Enlargement of the bridges resulted in the formation of multinucleated cells. Some glycoproteins were clustered on filaments outside the cell. The cytoplasmic changes showed : an intensive protein synthesis; numerous mitochondria closely associated with filaments and some lysosomes and numerous vesicules near the plasma membrane.     

Newly synthesized elastin is associated with neoplastic epithelial cells in human mammary carcinoma

Summary Indirect immunofluorescence with a purified antiserum to human foetal elastin has identified newly synthesized elastin on the membranes of neoplastic epithelial cells in human mammary carcinoma.This research was supported by a project grant from the Medical Research Council, London.     

Apoptotic cell death in the lactating mammary gland is enhanced by a folding variant of α-lactalbumin

Apoptosis is essential to eliminate secretory epithelial cells during the involution of the mammary gland. The environmental regulation of this process is however, poorly understood. This study tested the effect of HAMLET (human -lactalbumin made lethal to tumor cells) on mammary cells. Plastic pellets containing HAMLET were implanted into the fourth inguinal mammary gland of lactating mice for 3 days. Exposure of mammary tissue to HAMLET resulted in morphological changes typical for apoptosis and in a stimulation of caspase-3 activity in alveolar epithelial cells near the HAMLET pellets but not more distant to the pellet or in contralateral glands. The effect was specific for HAMLET and no effects were observed when mammary glands were exposed to native a-lactalbumin or fatty acid alone. HAMLET also induced cell death in vitro in a mouse mammary epithelial cell line. The results suggest that HAMLET can mediate apoptotic cell death in mammary gland tissue.Received 30 January 2004; received after revision 5 March 2004; accepted 16 March 2004     

Establishment and characterization of 3 human cell lines derived from intracerebral metastatic tumors]

Twelve human tumors were cultivated in vitro by the trypsinization technique and 3 cell lines were established. Each of these 3 lines showed individual characteristics which were maintained during passages. After inoculation into nude mice, 2 lines induced tumors which possessed the histologic features of the original human tumors (melanoma and carcinoma of stomach), the other line derived from a breast carcinoma was rejected.     

Comparison of exogenous cell fusion induced by a wild and two mutant strains of sheep Visna virus]

Exogen cell fusion induced in vitro by a wild strain of Visna virus of Sheep is compared with two mutant strains isolated from the precedent. One of them produces large plaques in vitro (strain LPF), and the other produces small plaques (strain SPF). These strains behave in different ways according to infection multiplicity, type of cells, temperature and timing of fusing activity. Taking the wild strain K 796 as a base of reference, the strain SPF seems to have a higher rate fusing activity and the strain LPF lower rate of fusing activity.     

Lactate dehydrogenase activity in cell subpopulations of 7,12-dimethylbenz(a)anthracene-induced mammary tumors

Heterogeneity of cells in a solid tumor prevents direct assessment of enzyme activity of cell subpopulations by conventional homogenization techniques. Lactate dehydrogenase (LDH) activity before and after ovariectomy and following estrogen supplementation in density-defined cell subpopulations from DMBA-induced mammary tumors was determined. Different levels of LDH activity were found in different cell subpopulations. After ovariectomy the level of LDH activity declined. Restoration of the circulatory estrogen level resulted in increased enzyme activity. The highest level of LDH was found in a band which consisted mainly of poorly differentiated cells. This cell subpopulation also tended to be more responsive to endocrine manipulation.     

Isolation of a growth-stimulating agent from human skin fibroblast cultures

Summary Cell-free supernatants were harvested from cultures of human skin fibroblasts, were applied on to DEAE-cellulose columns, and the first fraction eluted with phosphate-buffered saline contained the growth-stimulating agent. The eluted fraction was then passed through a series of amicon membranes. After passing through PM-10, the filtrate stimulated growth of bovine vascular endothelial, canine myocardial, and human mammary carcinoma cells.     

Changes in lactic dehydrogenase isoenzyme pattern in muscle of tumor-bearing mice

Summary The lactic dehydrogenase isoenzyme distribution shifts gradually toward the isoenzyme pattern of the tumor in mouse muscles located distally from a transplanted mammary carcinoma.This study was supported by a grant from the Minnesota Masonic Memorial Cancer Research Fund and, in part, by Grant No. 16-P-5681015-17 from the Rehabilitation Services Administration, U.S. Dept. of Health, Education and Welfare.     

Migration inhibition of mammary epithelial cells by Syk is blocked in the presence of DDR1 receptors

The non-receptor tyrosine kinase Syk is a well-characterized hematopoietic signal transducer, which is also expressed in non-hematopoietic cells. In epithelial cells, the function of Syk is not wholly known. It interacts with the receptor tyrosine kinase DDR1 and is frequently lost from metastatic mammary tumors. Here, using genetic tracing, we demonstrate Syk expression in murine mammary epithelium, myoepithelium and skin epithelium, but not in intestinal or lung epithelia. Investigating possible functions of Syk, we found a substantial suppression of cell mobility that depended on Syk kinase activity in trans-well migration and wounding assays. Co-expression of DDR1 resulted in constitutive interaction and strong activation of Syk kinase. Most importantly, Syk-mediated migration inhibition was blocked in the presence of DDR1, while conversely DDR1 knockdown restored migration inhibition. Our study identifies Syk as a potent inhibitor of epithelial migration and describes a first functional consequence of the interaction with the collagen receptor DDR1.     

Regulation of estrogen "receptors" in mammary tumors: action of prolactin in vivo

The effect of prolactin on estradiol receptors was determined in cytosol of estrogen-dependent mammary tumors of Sprague Dawley rats. Tumors were induced with 20 mg dimethylbenzanthracene, rats were ovariectomized, and the rats showing regression in tumor weight were given 1 mg sheep or rat prolactin for 5 days. Receptors were separated by dextran-charcoal and analyzed by sucrose gradient. Prolactin, milk proteins, serum proteins, and 1-alpha-feto-proteins were excluded immunologically. The estradiol receptors resembled uterine receptors in affinity, specificity, sedimentation, and nuclear transfer under estradiol influence. Castration diminished receptor content exponentially 170 f moles to 16 f moles/mg protein within 10 days; prolactin increased the number of receptors to 87 f moles compared with 15 in controls. Affinity, cellular location, and uterine receptor content were unaffected. Sheep and rat prolactin acted similarly. These results justify hypophysectomy as therapy for certain estrogen-dependent breast tumors.