Inducible expression of dominant negative insulin-like growth factor I receptor in MCF-7 breast cancer cells

The insulin-like growth factor I receptor (IGF-IR) is expressed in many cell types and is critical for normal growth and development. In the healthy mammary gland, the role of IGF-IR is not fully elucidated. However, IGF-IR, which is primarily expressed in the mammary epithelial cells, is known to play an obligatory role in cellular transformation, facilitating the progression to breast cancer. We have utilized the tetracycline regulatory (tet-on) system to generate an in vitro model system to allow us to further investigate IGF-I/IGF-IR function in mammary epithelial cells. A plasmid construct containing a mutant IGF-I receptor (IGF-IR-DN) fused to the tetracycline operator (tetOPh_CMV-IGF-IR-DN) was stably transfected into MCF-7 human breast cancer cells. The conditional regulation of the IGF-IR-DN gene expression was studied in four independent clonal lines. The translated IGF-IR-DN protein was detected only in the stably transfected doxycycline-induced cells, and its expression was up-regulated (three- to sixfold) following induction. IGF-I stimulated cell proliferation diminished (twofold) in doxycycline-induced cells compared to uninduced cells, demonstrating that the transgene construct was functional and ruling out any pleiotropic effect that may be attributed to doxycycline. Interestingly, autophosphorylation of the IGF-IR and phosphorylation of the downstream substrate, insulin receptor substrate-1 (IRS-1), was not inhibited in doxycycline/IGF-I treated cells, suggesting the possibility that activation of downstream substrates other than the IRS-1 may be critical for optimal cell proliferation. This novel in vitro model should allow us to more directly examine the role of IGF-I/IGF-IR signaling and function in mammary epithelial cells.     

超声与CT 联合诊断肾上腺占位病变的价值探讨

目的：探讨超声与C T联合应用诊断肾上腺占位性病变的价值。方法将病理证实的55例肾上腺肿瘤、2例囊肿及超声、C T随访确诊的13例肾上腺血肿,共70例占位性病变的超声与C T联合诊断作回顾性分析,并分别与超声、C T单项检查进行比较。结果70例肾上腺占位病变（嗜铬细胞瘤14例,髓样脂肪瘤13例,皮质腺瘤15例,皮质腺癌5例,淋巴瘤2例,转移性肿瘤6例,囊肿2例,血肿13例）,超声与C T联合应用定性诊断正确率达88．6％,而超声、C T 单项检查定性诊断正确率分别为62．8％、72．9％,联合应用与单项检查比较均有显著差异,与超声单项检查比较（χ2＝12．58,P＜0．05）,与C T单项检查比较（χ2＝5．55,P＜0．05）。结论超声与C T联合应用,可显著提高肾上腺占位性病变定性诊断正确率。     

Rapid interaction of prolactin with mouse mammary gland explants.

Exposure of mouse mammary gland explants to prolactin at 0 degrees C, for periods as brief as 10 seconds, caused a stimulation of labeled uridine incorporation into RNA during a subsequent incubation for 4 h at 37 degrees C. Furthermore, a 2-h wash of the prolactin-exposed explants in media at 0 degrees C did not attenuate the hormonal effect. A similar exposure of explants to insulin, followed by a 2-h wash at 0 degrees C, caused the abolition of the insulin stimulation of labeled uridine incorporation into RNA. The results suggest that there is a rapid and relatively stable interaction of prolactin with the mammary gland, while the interaction of insulin with this tissue would appear to be less stable.     

Different Mechanisms Lead to the Angiogenic Process Induced by Three Adenocarcinoma Cell Lines

Neoangiogenesis is essential for tumor and metastasis growth, but this complex process does not follow the same activation pathway, at least in tumor cell lines originated from different murine mammary adenocarcinomas. LMM3 cells were the most potent to stimulate new blood vessel formation. This response was significantly reduced by preincubating cells with indomethacin and NS-398, non-selective cyclooxygenase (COX) and COX-2 selective inhibitors, respectively. COX-1 and COX-2 isoenzymes were both highly expressed in LMM3 cells, and we observed that indomethacin was more effective than NS-398 to inhibit prostaglandin E2 (PGE2) synthesis. In addition, nitric oxide synthase (NOS) inhibitors, Nomega monomethyl L-arginine and aminoguanidine, also reduced LMM3-induced angiogenesis and nitric oxide (NO) synthesis as well. NOS2 > NOS3 proteins and arginase II isoform were detected in LMM3 cells by Western blot. The latter enzyme was also involved in the LMM3 neovascular response, since the arginase inhibitor, Nomega hydroxy L-arginine reduced the angiogenic cascade. On the other hand, parental LM3 cells were able to stimulate neovascularization via COX-1 and arginase products since only indomethacin and Nomega hydroxy L-arginine, which diminished PGE2 and urea synthesis, respectively, also reduced angiogenesis. In turn, LM2 cells angiogenic response could be due in fact to PGE2-induced VEGF liberation that stimulated neoangiogenesis at very low levels of NO.     

An unusual case of left internal mammary artery ostial disease: clarifying role of intravascular ultrasound.

Stenosis at the origin of the left internal mammary artery graft is rare. We present a case with a suspected stenosis involving the origin of the left internal mammary artery that conventional angiography failed to demonstrate convincingly. Intravascular ultrasound illustrated a severe stenosis and the patient underwent successful stenting of the left internal mammary artery origin. The intravascular ultrasound finding of a dissection flap, just distal to the left internal mammary artery origin, suggests that local trauma to the vessel from prior catheterization procedures may have been responsible for the progressive narrowing at the left internal mammary artery ostium.     

Mammary gland sympathetic innervation is a major component in type 1 deiodinase regulation

Recent observations have shown that in lactating rats previously deprived of suckling, either suckling stimulus or ip injection of norepinephrine was capable of increasing mammary deiodinase type 1 (M-D1) mRNA content and enzyme activity. In the present work, we show that intact efferent sympathetic mammary innervation is required to restore both mammary D1 mRNA content and enzyme activity, whereas suckling-induced secretion of catecholamines from the adrenal glands does not seem to participate in M-D1 enzyme regulation. The data also indicate that the sympathetic reflex activation in response to suckling involves two complementary autonomic components: (1) activation, presumably through mammary segmental arrangement affecting neighboring mammary glands; and (2) an individual reflex regulatory mechanism capable of maintaining M-D1 activity within each mammary gland. In addition to these findings, we show that the suckling-induced sympathetic activation of M-D1 activity could be blocked by prior activation of ductal mechanoreceptors. This set of regulatory and counterregulatory mechanisms seems to ensure the optimal control of mammary energetic expenditure according to litter size.     

Prolactin regulates mammary epithelial cell proliferation via autocrine/paracrine mechanism

Prolactin (PRL) is essential for a number of developmental events in the mammary gland. Work with PRL and PRL receptor knockout mice has shown that PRL indirectly regulates ductal side branching during puberty and directly controls lobuloalveolar development and lactogenesis during pregnancy. Anterior pituitary or placental PRL is thought to be responsible for these functions via an endocrine mechanism; however, PRL is also produced in a number of extrapituitary sites including the mammary gland. The physiologic relevance of mammary PRL remains unknown. In this study we utilized mammary recombination in Rag1^−/− hosts, to determine whether mammary PRL plays a role in the regulation of mammary gland development. Mammary glands formed with the PRL gene deleted from either the epithelium, stroma, or both displayed normal development, on the basis of whole mount and hematoxylin and eosin histology, during puberty and lactation. At the end of pregnancy, a 2.8-fold decrease in bromodeoxyuridine incorporation was observed in the epithelial cells of mammary glands formed using PRL knockout epithelium compared with those formed using wildtype epithelium. No balancing alteration in the rates of apoptosis was detected. Thus, mammary-derived PRL influences mammary epithelial cell proliferation via an autocrine/paracrine mechanism, establishing a physiologic function for mammary PRL during mammopoiesis.     

Stenting the distal anastomotic site of the left internal mammary artery graft: a case report

The major problem associated with the long-term patency of the internal mammary artery graft is the early occurrence of stenosis usually at its distal anastomotic site; its management by balloon angioplasty has been associated with a high success rate. We report the case of an unsuccessful balloon angioplasty of an anastomotic stenosis of a left internal mammary artery graft that was successfully managed by stenting with one-half of a Palmaz-Schatz stent. © 1994 Wiley-Liss,Inc..     

Left internal mammary graft stenosis and restenosis following angioplasty and stenting

Coronary bypass grafts using the internal mammary artery usually have an excellent record of success and long term patency. We report a 42 year old man who initially presented with a history of atypical left sided chest pain, who had coronary artery bypass surgery for a severe stenosis in his proximal left anterior descending coronary artery (LAD) and moderate stenosis of his proximal circumflex artery, with his LIMA being grafted to his mid-LAD and a saphenous venous graft to the proximal LAD. He subsequently developed multiple stenoses in the LIMA graft which required coronary augioplasty and stenting, on more than one occasion, in view of very rapid restenosis within the LIMA graft.


Keywords: graft patency; left internal mammary artery grafts; restenosis; stenosis     

3,4-Bis(3′-hydroxyphenyl)hexane — A new mammary tumor-inhibiting compound

Summary The syntheses of the hexestrol derivatives 3,4-bis-(3-hydroxyphenyl)hexane (4a), 3,4-bis(4-fluoro-3-hydroxyphenyl)hexane (4b), 3,4-bis(3, 4dihydroxyphenyl)hexane (4c), and 3,4-bis(3,4-diacetoxyphenyl)hexane (4d) are described. All compounds showed a marked, competitive inhibition of the estradiol receptor interaction (K _a4c>K_a4a>K_a4d>K_a4b). Evaluated in the mouse uterine weight test compounds 4c and 4d almost reached the estrone effect, whereas 4a and 4b did not produce full uterotrophic response. Compounds 4a-d antagonized the estrone stimulated uterine growth of the immature mouse. Compound 4a (NSC-297170) exhibited a specific, dose-related growth inhibition of the estrogen responsive MCF-7 human breast tumor cell line. Tested on the 9,10-dimethyl-1,2-benzanthracene-induced hormonedependent mammary adenocarcinoma of the Sprague-Dawley rat all compounds showed marked inhibition of tumor growth. As in all experiments compounds 4a and 4b, which is resistant to hydroxylation in 4position exhibited an identical pattern of action, which is different from that shown by compound 4c, the effect of compound 4a cannot be explained by its possible catechol metabolite 4c.Supported by grants from the Deutsche Forschungsgemeinschaft and the Verband der Chemischen Industrie-Fonds der Chemischen Industrie