Assembling semiconducting molecules by covalent attachment to a lamellar crystalline polymer substrate

We have investigated the potential of polymers containing precisely spaced side-branches for thin film applications, particularly in the context of organic electronics. Upon crystallization, the side-branches were excluded from the crystalline core of a lamellar crystal. Thus, the surfaces of these crystals were covered by side-branches. By using carboxyl groups as side-branches, which allow for chemical reactions, we could functionalize the crystal with semiconducting molecules. Here, we compare properties of crystals differing in size: small nanocrystals and large single crystals. By assembling nanocrystals on a Langmuir trough, large areas could be covered by monolayers consisting of randomly arranged nanocrystals. Alternatively, we used a method based on local supersaturation to grow large area single crystals of the precisely side-branched polymer from solution. Attachment of the semiconducting molecules to the lamellar surface of large single crystals was possible, however, only after an appropriate annealing procedure. As a function of the duration of the grafting process, the morphology of the resulting layer of semiconducting molecules changed from patchy to compact.publishe

Growth-Inhibitory Actions of Analogues of Luteinizing Hormone Releasing Hormone on Tumor Cells

The expression of LHRH and its receptor has been demonstrated in a number of human malignant tumors, including cancers of the breast, ovary, endometrium, and prostate. These findings suggest the presence of an autocrine regulatory system based on LHRH. Dose-dependent antiproliferative effects of LHRH agonists in cell lines derived from these cancers have been observed by various investigators. LHRH antagonists also have marked antiproliferative activity in most of the ovarian, breast, and endometrial cancer cell lines tested, indicating that the dichotomy of LHRH agonists and antagonists might not apply to the LHRH system in cancer cells. Findings from our laboratories suggest that the classical LHRH receptor signal-transduction mechanisms, known to operate in the pituitary, are not involved in the mediation of antiproliferative effects of LHRH analogues in cancer cells. Results obtained by several groups, including ours, instead suggest that LHRH analogues interfere with the mitogenic signal transduction of growth-factor receptors and related oncogene products associated with tyrosine kinase activity. The pharmacological exploitation of these direct antiproliferative actions of LHRH analogues might provide new therapeutic approaches to these cancers. (Trends Endocrinol Metab 1997;8:355–362). © 1997, Elsevier Science Inc

High Affinity Binding and Direct Antiproliferative Effects of LHRH Analogues in Human Ovarian Cancer Cell Lines

Recently, specific binding sites for luteinizing hormone releasing hormone (LHRH) and its analogues have been demonstrated in biopsy samples of human epithelial ovarian cancer. Their biological significance remained obscure. In this study we ascertained whether such LHRH-binding sites are also present in the human epithelial ovarian cancer cell lines EFO-21 and EFO-27 and if they could mediate antiproliferative effects of LHRH analogues. Using [125I, D-Trp6]LHRH, a high affinity/low capacity binding site was detected in both lines: EFO-21 (Kd1 = 1.5 x 10(-9) M; binding capacity (Bmax1) = 4.9 fmol/10(6) cells) and EFO-27 (Kd1 = 1.7 x 10(-9) M; Bmax1 = 3 fmol/10(6) cells). In addition, a second class of low affinity/high capacity binding sites (EFO-21: Kd2 = 7.5 x 10(-6) M; Bmax2 = 24 pmol/10(6) cells; EFO-27: Kd2 = 4.3 x 10(-6) M; Bmax2 = 14.5 pmol/10(6) cells) was demonstrated. Specific binding of [125I, D-Trp6]LHRH was displaced with nearly equal efficiency by unlabeled [D-Trp6]LHRH, the LHRH-antagonists SB-75 and Hoe-013, and by native LHRH but not by unrelated peptides such as oxytocin and somatostatin. In the presence of 10(-5) M agonist [D-Trp6]LHRH, the proliferation of both cell lines was significantly reduced to 77% of controls after 24 h and to approx. 60% after 6 days. Lower concentrations (10(-9) M) of the agonist, significantly decreased the proliferation to 87.5% for EFO-21 and 86% for EFO-27 after 6 days. These antiproliferative effects were enhanced by increasing doses of [D-Trp6]LHRH and were maximal at 10(-5) M (EFO-21: 65.5% of control, EFO-27: 68% of control). Similar dose-dependent antiproliferative effects were obtained in EFO-21 line with the LHRH-antagonists SB-75 and Hoe-013, while these analogues had no effects on the proliferation of EFO-27 cells. SB-75 partly antagonized the antiproliferative effect of [D-Trp6]LHRH in a dose dependent way in the EFO-27 line. These data suggest that LHRH analogues can directly inhibit the in vitro proliferation of human ovarian cancer cells. This effect might be mediated through the high affinity LHRH binding sites

Luteinizing hormone‐releasing hormone agonist triptorelin in combination with cytotoxic chemotherapy in patients with advanced ovarian carcinoma: A prospective double blind randomized trial

BACKGROUND Several lines of evidence suggest that the proliferation of ovarian carcinoma might be stimulated by gonadotrophins. A number of Phase I/Phase II clinical trials have reported that the suppression of endogenous luteinizing hormone and follicle‐stimulating hormone secretion by luteinizing hormone‐releasing hormone (LHRH) analogs induced objective remissions and/or disease stabilization in 10–30% of patients with advanced refractory ovarian carcinoma. The current study was performed to evaluate whether the addition of LHRH agonist treatment to standard platinum‐based chemotherapy could prolong survival of patients with surgically treated Stage III or IV epithelial ovarian carcinoma. METHODS One hundred and thirty‐five patients with Stage III or IV epithelial ovarian carcinoma participated in this prospective randomized double blind trial. After cytoreductive surgery, 69 patients received monthly injections of a depot preparation of the LHRH agonist [D‐Trp6] LHRH (triptorelin, 3.75 mg) and 66 patients received placebo until their deaths or termination of the trial, respectively. All patients were treated with a standard platinum‐based chemotherapy, and, if necessary, with second‐ or third‐line cytotoxic regimens. RESULTS Endogenous gonadotrophins were reliably suppressed in patients treated with triptorelin. However, their progression free and overall survival were not significantly different from that of patients receiving placebo injections (statistical power > 80% for a difference between both groups of; ce20%). CONCLUSIONS The results of this trial suggest that the suppression of endogenous gonadotrophins by conventional doses of an LHRH agonist produces no relevant beneficial effects in patients with advanced ovarian carcinoma who receive standard surgical cytoreduction and cytotoxic chemotherapy. Cancer 1996;78:1452‐60

The endogenous cannabinoid system affects energy balance via central orexigenic drive and peripheral lipogenesis

The cannabinoid receptor type 1 (CB1) and its endogenous ligands, the endocannabinoids, are involved in the regulation of food intake. Here we show that the lack of CB1 in mice with a disrupted CB1 gene causes hypophagia and leanness. As compared with WT (CB1(+/+)) littermates, mice lacking CB1 (CB1(–/–)) exhibited reduced spontaneous caloric intake and, as a consequence of reduced total fat mass, decreased body weight. In young CB1(–/–) mice, the lean phenotype is predominantly caused by decreased caloric intake, whereas in adult CB1(–/–) mice, metabolic factors appear to contribute to the lean phenotype. No significant differences between genotypes were detected regarding locomotor activity, body temperature, or energy expenditure. Hypothalamic CB1 mRNA was found to be coexpressed with neuropeptides known to modulate food intake, such as corticotropin-releasing hormone (CRH), cocaine-amphetamine–regulated transcript (CART), melanin-concentrating hormone (MCH), and prepro-orexin, indicating a possible role for endocannabinoid receptors within central networks governing appetite. CB1(–/–) mice showed significantly increased CRH mRNA levels in the paraventricular nucleus and reduced CART mRNA levels in the dorsomedial and lateral hypothalamic areas. CB1 was also detected in epidydimal mouse adipocytes, and CB1-specific activation enhanced lipogenesis in primary adipocyte cultures. Our results indicate that the cannabinoid system is an essential endogenous regulator of energy homeostasis via central orexigenic as well as peripheral lipogenic mechanisms and might therefore represent a promising target to treat diseases characterized by impaired energy balance