miR-34 and SNAIL form a double-negative feedback loop to regulate epithelial-mesenchymal transitions

Recently, the inhibition of epithelial-mesenchymal-transition (EMT) by p53 has been described as a new mode of tumor suppression which presumably prevents metastasis. Here we report that activation of p53 down-regulates the EMT-inducing transcription factor SNAIL via induction of the miR-34a/b/c genes. Suppression of miR-34a/b/c caused up-regulation of SNAIL and cells displayed EMT markers and related features, as enhanced migration and invasion.  Ectopic miR-34a induced mesenchymal-epithelial-transition (MET) and down-regulation of SNAIL, which was mediated by a conserved miR-34a/b/c seed-matching sequence in the SNAIL 3'-UTR. miR-34a also down-regulated SLUG and ZEB1, as well as the stemness factors BMI1, CD44, CD133, OLFM4 and c-MYC. Conversely, the transcription factors SNAIL and ZEB1 bound to E-boxes in the miR-34a/b/c promoters, thereby repressing miR-34a and miR-34b/c expression. Since ectopic miR-34a prevented TGF-β-induced EMT, the repression of miR-34 genes by SNAIL and related factors is part of the EMT program. In conclusion, the frequent inactivation of p53 and/or miR-34a/b/c found in cancer may shift the equilibrium of these reciprocal regulations towards the mesenchymal state and thereby lock cells in a metastatic state.

[Conformal irradiation technique for the peri- and retrobulbar space in endocrine orbitopathy]

The clinical target volume (CTV) for the irradiation of the endocrine orbitopathy (Graves ophthalmopathy) includes the peri- und retrobulbar space with the extraocular muscles. We present here a conformal irradiation technique aimed at optimal coverage of the CTV. The irradiation technique consists of two rotation fields with a central lens block and two lateral fixed fields with dorsal blocking. In each Gantry position, the lenses are faded out through the central lens block. The isocenter of the two rotation fields is located in the lenses. For quality assurance of this irradiation technique, verification of the dose distribution was performed by film dosimetry using the humanoid Aldersone phantom. The use of this irradiation technique yielded a dose distribution with conformal CTV coverage of the peri- and retrobulbar space and of the extraocular muscles. The film dosimetry of the Aldersone phantom showed a maximal deviation of 5% between the measured and the calculated dose distribution. The radiation load to the eye lenses was 25% of the applied total dose.

Target volume definition and target conformal irradiation technique for breast cancer patients

The aim of this study was to present the target volume and irradiation technique in the most complex situation where the breast or chest wall and the locoregional lymphatics (mammaria interna lymph nodes, axillary and supraclavicular lymph nodes) have to be irradiated. The study comprised 125 breast cancer patients treated with curative intent after primary surgery in the last two years at our institute. In 62 cases the target volume included the breast or chest wall and the locoregional lymphatics, which were treated using our irradiation technique. The target conformal irradiation technique is a multiple non-opposed beams one isocenter technique developed to protect the heart and lungs. This technique, consisting of several rotation beams modulated with wedge filters and individual lung absorbers as well as additional fixed beams, was used in our study to apply a homogeneous dose of 46 to 56 Gy to the target volume; the irradiation technique was optimized by means of dose-volume histograms. After pre-localization, the patients underwent computerized tomographic scanning, with sections at 1.0 cm intervals. Contouring of target volume and organs at risk was carried out with a MULTIDATA workstation for regions of interest (mammaria interna and/or axillary and/or supraclavicular lymphatics and the breast or chest wall) as well as the organs at risk, such as heart and lung parenchyma. Planning target volume coverage was examined by three-dimensional isodose visualization for all CT axial sections for each patient. To determine the incidence of acute or late side effects on the lung parenchyma, conventional chest x-rays and CT studies were carried out at 1 month, 3 months and 6 months after completion of radiotherapy. Dose-volume histogram analysis revealed that this irradiation technique permits the application of a homogeneous dose to the target volume, conforming to the ICRU norms. The maximum dose applied to the ipsilateral lung parenchyma was less than 50-70% of the prescribed dose in the target volume. For left-located primaries, the highest dose applied to the myocardium is less than 30-50% of the dose in the target volume. Acute side effects, such as radiation pneumonitis, were noted in 8% (5/62) of the treated patients. Late side effects (grade I) in the lung were observed in 6.4% of the patients (4 patients) and occurred only in areas that had received more than 70% of the prescribed dose. We conclude that it is possible to apply a homogeneous dose distribution with a one isocenter multiple beams irradiation technique to the most complex target volume, such as the breast or chest wall and the locoregional lymphatics, with a minimum of side effects guaranteed.

Prevention of N-nitrosobis(2-oxopropyl)amine-induced nasal cavity tumors in rats by orchiectomy

Bilateral orchiectomy, performed 1 week before initiation of weekly sc injections of N-nitrosobis(2-oxopropyl)amine (BOP), prevented induction of hyperplastic and neoplastic lesions in the nasal and paranasal cavities of outbred Wistar-derived MRC rats. However, in BOP-treated rats without surgery or with bilateral vesiculectomy, the incidences of these lesions were 100 and 90%, respectively. Literature review indicates that nasal and paranasal lesions occur predominantly in male domestic animals as well as in human males and suggests a possible hormone dependency of these lesions.

Modifying factors in pancreatic carcinogenesis in the hamster model. I. Effect of protein-free diet fed during the early stages of carcinogenesis

The role of protein in pancreatic carcinogenesis was examined in outbred Syrian golden hamsters treated with the pancreatic carcinogen N-nitrosobis(2-oxopropyl)amine (BOP) and fed a purified protein-free diet (PPFD). The PPFD was fed for 28 days from 8 weeks of age; before and after animals were fed PPFD, they were given a commercial diet (CD). BOP was given before PPFD feeding (group 1) or at 18 days (group 2) and 28 days (group 3) from the beginning of the PPFD feeding. BOP-treated control hamsters (group 4) were pair-fed a purified control diet (PCD) instead of PPFD. All animals fed PPFD and PCD were returned to a CD for the rest of the experiment, which was terminated in each group 52 weeks after BOP treatment. The results showed a highly significant reduction of tumor incidence (P less than 0.0001) in hamsters that received PPFD, when compared to those fed PCD, regardless of the time of carcinogen administration during the dietary regimen. Hamsters treated with BOP at 18 days of PPFD (group 2) developed neither benign nor malignant pancreatic tumors. The inhibition of pancreatic neoplasms was not related to reduced calorie consumption, since this occurred in the BOP-treated hamsters that were pair-fed the PCD diet. The results indicated that both the initiation and promotion of pancreatic carcinogenesis with BOP in hamsters can be inhibited by lack of protein in the diet given for 4 weeks during the early stages of the neoplastic process.

Cyclosporin receptors on human lymphocytes

Utilizing (3H) cyclosporin C (3H CS-C), a dihydroderivative of cyclosporin A (CS-A), an assay for cyclosporin receptors on human peripheral blood lymphocytes was developed. The specific binding of (3H) CS-C was saturable, time-dependent, and reversible. A Kd of 1.2 x 10(-7) M and a maximum binding capacity (Bmax) of 7 pmol/10(6) cells was calculated from equilibrium binding studies. A Scatchard analysis confirmed a single population of high affinity binding sites and about 7 x 10(5) sites/cell. Kinetic analysis of specific binding at 37 degrees C yielded a pseudo-first order rate association constant of 1.1 x 10(6) M-1 min-1 and a zero order dissociation rate constant of 0.19 min-1. The Kd 1.7 x 10(-7) M calculated from kinetic studies agreed well with the value of 1.2 x 10(-7) M determined in equilibrium binding studies. Regarding the specificity of binding, (3H) CS-C binding to lymphocytes was inhibited with CS-A and CS-C; however, no inhibition with the biologically inert keto-CS-A was observed. Mitogens and various growth factors did not compete for the binding site when added simultaneously with the radiolabel. However, pretreatment with T cell mitogens such as PHA, Con A, or the OKT3 antibody reduced (3H) CS-C binding significantly. These results suggest that the binding site for CS-A is closely associated with the mitogenic receptor on lymphocytes.

Cyclosporin receptors on human lymphocytes

Utilizing (3H) cyclosporin C (3H CS-C), a dihydroderivative of cyclosporin A (CS-A), an assay for cyclosporin receptors on human peripheral blood lymphocytes was developed. The specific binding of (3H) CS-C was saturable, time-dependent, and reversible. A Kd of 1.2 x 10(-7) M and a maximum binding capacity (Bmax) of 7 pmol/10(6) cells was calculated from equilibrium binding studies. A Scatchard analysis confirmed a single population of high affinity binding sites and about 7 x 10(5) sites/cell. Kinetic analysis of specific binding at 37 degrees C yielded a pseudo-first order rate association constant of 1.1 x 10(6) M-1 min-1 and a zero order dissociation rate constant of 0.19 min-1. The Kd 1.7 x 10(-7) M calculated from kinetic studies agreed well with the value of 1.2 x 10(-7) M determined in equilibrium binding studies. Regarding the specificity of binding, (3H) CS-C binding to lymphocytes was inhibited with CS-A and CS-C; however, no inhibition with the biologically inert keto-CS-A was observed. Mitogens and various growth factors did not compete for the binding site when added simultaneously with the radiolabel. However, pretreatment with T cell mitogens such as PHA, Con A, or the OKT3 antibody reduced (3H) CS-C binding significantly. These results suggest that the binding site for CS-A is closely associated with the mitogenic receptor on lymphocytes.

[Ultrasonography in the diagnosis of fatty liver (author's transl)]

Diagnostic relevance of ultrasonography was studied prospectively and controlled by peritoneoscopy and biopsy. 310 cases were investigated, 126 of these had fatty infiltration of the liver between 5% and 95%, which was diagnosed correctly in 92% of the cases by ultrasonography on the basis of increased reflexes. The incidence of correct diagnoses was 95% resp. 100% in cases with more than 10% resp. 50% fatty infiltration of the liver. Thus, diagnosis of fatty liver can be achieved with high sensitivity (fat infiltration of more than 10% may be recognized) and high specificity (only 4.35% false positives) by ultrasonography. Ultrasonography is a simple, non-invasive, and fast method suited for screening and follow-up in this condition.

Cyclosporin receptor on mouse lymphocytes

Specific binding of [3H]-cyclosporin C (3H-CS-C), an immunosuppressive oligopeptide, was characterized on different mouse lymphocytes. The binding was saturable, time-dependent and reversible; and KD of 1.5 x 10(-7) M and maximum binding capacity Bmax of 35 pmol/4 x 10(6) cells was found for thymocytes. A computerized analysis of the data confirmed a single population of high affinity binding sites. Lymphocytes of different organs differed in their Bmax: thymus greater than spleen greater than mesenteric lymph node (pure T cells) greater than mesenteric lymph node (pure B cells). Erythrocytes did not show a specific binding.

[The uni-quatro camera - a new camera for documentation of monitor pictures (author's transl)]

A new camera system is described, which was devised to take pictures of monitor screens on special X-ray film, and it is compared with conventional methods of documentation. Quality of pictures obtained with this method is optimal, handling is quick and simple, and, in spite of that, the camera is smaller and less expensive than other multiformate cameras. Polaroid, special X-ray films and other films may be used interchangeable for all sorts of monitor screens. A report is given about the routine use of this system in ultrasonography.