Enhanced neoplastic transformation in an inhomogeneous radiation field: an effect of the presence of heavily damaged cells.

In the inhomogeneous radiation field surrounding small beta-particle sources, nonlethally and heavily damaged cells are in proximity, permitting interaction via extracellular signals. This situation is typical of hot particles such as those released during the accident at Chernobyl. Beta-particle-emitting yttrium-90 wires (average energy 934 keV) were employed to investigate radiation-induced neoplastic transformation under these conditions. Integrated 24-h doses ranging from 0 to 750 Gy across the exposure field were applied. At equal levels of toxicity a 10-fold enhancement of neoplastic transformation frequency in C3H 10T1/2 cells was observed in the presence of heavily damaged cells. Homogeneous fields of low-dose-rate beta-particle radiation produced neoplastic transformation frequencies typical for comparable photon exposures reported in the literature.

Genome lability in radiation-induced transformants of C3H 10T1/2 mouse fibroblasts.

We have been investigating radiation-induced neoplastic transformants of C3H 10T1/2 mouse fibroblasts for evidence of heritable changes. C3H 10T1/2 cells were treated with 8 Gy X rays. After approximately 8 weeks of culture, type II/III foci were isolated from the monolayer using cloning rings. Cell lines developed from these foci, and clones established from these cell lines, were examined for DNA content. The isolated focus-derived populations and derived clones often display aneuploidy and/or polyploidization. In one instance a clone (derived from a single cell) displayed multiple polyploidies. During passage the ploidy of many of the anomalous populations gradually reverted to the ploidy of the non-neoplastically transformed state. The morphological features associated with the neoplastic transformation event were nevertheless retained. The results demonstrate that exposure to radiation can induce, in association with morphological neoplastic transformation, a heritable, genomically labile state.

A pure beta line source to assess hot particle effects in vitro.

A model system is presented for assessing the biological effects of inhomogeneous irradiation fields resulting from exposure to particulate radioactive matter (hot particles). The resulting harm per unit dose to tissue is qualitatively different from homogeneous irradiation sources because of specific hot particle effects such as wasting of dose to necrotic tissue (overkill) and formation of microlesions leading to growth stimulation in adjacent tissue. In the case of beta-emitters, many of the cells in adjacent tissue receive considerable sublethal doses. To assess the influence of local necrosis and growth stimulation on radiation transformation in vitro, a neutron activated short 90Y wire was attached to the bottom foil of a cell culture dish. The system achieves doses of up to 200 Gy h(-1) directly above the wire, rapidly falling off within a few mm to less than 0.5 Gy h(-1). Acute cell death of murine M3-1 cells was observed in the highest dose regions. Colony-forming ability as a function of distance from the wire was investigated. The surviving fraction decreased over several orders of magnitude between 3 and 10 mm from the wire. This report describes the physical characteristics of the model system and subsequent biological survival data for mammalian cell culture. It is a useful and versatile system for modeling inhomogeneous radiation field effects.

[Sexual medicine cases of treatment--developments 1980 - 1990 - 2004]. / Sexualmedizinische Behandlungsfälle - Entwicklungen 1980 - 1990 - 2004.

Sexual dysfunctions can adversely affect men's and women's satisfaction with life over a prolonged period. Besides sexual medicine services in primary medical care, in Switzerland there exist specialized consultation services at University Hospitals. The assessment of the case histories of three years (1980, 1990, and 2004) of the Sexual Medicine Consultation Service at Zurich University Hospital provided the following results: the most common disorders are lack/loss of libido in women and erectile dysfunction in men. Treatment options for sexual disorders have become more differentiated in recent years. The collaboration between the doctors making the referral and the sexual medicine specialists improved markedly between 1980 and 2004. After a diagnostic assessment and a primary treatment in the specialized consultation service, many patients are referred back to the referring doctors for further treatment. Basic and further training in sexual medicine ought to be intensified and improved.

Endovascular treatment of an intramural aortic haematoma following cardiopulmonary resuscitation for myocardial ischemia with ventricular fibrillation.

Cardiopulmonary resuscitation by manual cardiac compression can restore cardiocirculatory function but can also injure patients. Commonly reported are skeletal fractures of the rips and sternum, while injuries to the large thoracic vessels will frequently be lethal. We report the case of a 57-year-old male patient with sudden cardiac arrest because of myocardial ischemia with ventricular fibrillation, successful cardiopulmonary resuscitation, associated with an intramural haematoma (IMH) of the descending thoracic aorta treated by endovascular aortic repair. Secondary coronary angiography revealed a severe three vessel coronary disease with an occlusion of the proximal anterior descending branch and a subtotal stenosis of the first segmental branch of the left coronary artery (LCA) and a high-grade stenosis of the posterolateral segmental branch of the circumflex left coronary artery. Stenotic segments of coronary arteries were treated successfully by implantation of three drug-eluting stents followed by dual antiplatelet therapy. The patients recovered almost completely and was discharged for further rehabilitation after 3 weeks.

Radiation-induced genetic instability: no association with changes in radiosensitivity or cell cycle checkpoints in C3H 10T1/2 mouse fibroblasts.

We investigated various phenotypic characteristics of radiation-induced morphologically transformed C3H 10T1/2 mouse fibroblasts. The cells were treated with 8 Gy x-rays, and type II/III foci were isolated. Cell lines were developed from these foci, and subsequently clones were established from these focal lines. The clones were examined for DNA content, radiosensitivity and inducible cell cycle arrests. Besides the morphological changes associated with the transformed state, the major difference between the isolated focal lines or derived clones and the parental C3H 10T1/2 line was one of ploidy. The transformed cells often displayed aneuploid and multiple polyploid populations. No change in the radiosensitivity of the transformed cells was observed. Furthermore, the two major radiation- and staurosporine-induced G1 and G2 cell cycle arrests observed in the parental cell line were also observed in the morphological transformants, suggesting that checkpoint function was normal.