In previous studies we showed that transforming growth factor-β1 induces apoptosis in hepatocyte cultures and regressing livers, the mature form being more potent than the transforming growth ...factor-β1 latency-associated protein. In this study we addressed the question of whether apoptosis can be induced within a short time after administration of transforming growth factor-β1. Five hours after a single intravenous injection of 25 μg mature transforming growth factor-β1/kg body weight, apoptosis is augmented ninefold in the regressing rat liver. A second preceding application induces no further augmentation. Transforming growth factor-β1 latency-associated protein shows no effect with either regimen. Morphological evaluation shows that 5 hr after injection of transforming growth factor-β1 nearly all apoptotic bodies are already engulfed by their neighbor cells. After homogenization of the transforming growth factor-β1-treated livers, the condensed apoptotic bodies are not destroyed and remain in the nuclear pellet. No DNA fragmentation into oligosomes could be detected after purification of the DNA from the nuclear pellet and application to conventional gel electrophoresis. Application of
in situ nick translation, which allows detection of DNA single- and double-strand breaks in individual apoptotic bodies, also revealed no substantial fragmentation of the DNA in apoptotic bodies. These studies show that transforming growth factor-β1 is able to induce apoptosis within a rather short time and also suggest that
in vivo digestion of the DNA does not lead to chromatin condensation.
1. Myocardial hypertrophy, for instance in patients with hypertensive heart disease, is characterized by a reduction of coronary vascular reserve, even in the presence of normal coronary arteries. In ...hypertensive animals, on the microcirculatory level functional changes can be observed before the onset of any structural rarefications. In 10 rats with renal hypertension and pressure-induced left ventricular hypertrophy (LVH), the microcirculation of the left ventricular myocardium was studied using in vivo fluorescence microscopy and morphometric analysis. Renal hypertension was provoked by clipping of the left renal artery. After 8 weeks, systolic blood pressure in LVH rats averaged 172 +/- 8 mm Hg, compared to 91 +/- 2 mm Hg in 10 normotensive (NT) rats. In LVH rats, distances of plasma-perfused capillaries were significantly increased (NT = 17.7; LVH = 20 microns; p less than 0.001). Volume density, surface density, and length density of capillaries in LVH rats were reduced by 20% compared to NT rats. Capillary red cell content as measured by the ratio of capillaries filled with red cells to those containing plasma alone (Q) in LVH animals exceeded that in NT rats (LVH: Q = 0.83 +/- 0.04; NT: Q = 0.77 +/- 0.04; p less than 0.025). During hypoxia (H, 5% O2) capillary red cell recruitment in LVH rats (Q: control c = 0.83; H = 0.95) was diminished by 33% as compared to NT rats (Q: c = 0.77; H = 0.95). Thus, in addition to the decreased capillary density, the reduction of capillary red cell recruitment may be responsible for chest pain in patients with LVH and normal coronary arteries.
Intensity modulated radiotherapy (IMRT) combined with recently developed noninvasive image-guided targeting techniques for tumor localization/repositioning provide a means to further improve on ...conformal radiotherapy of prostate cancer by optimally sparing the rectum. This refined approach may potentially improve treatment results for locally advanced prostate cancer while reducing side effects. This review summarizes the clinical requirements for effective prostate radiotherapy and describes the new technology that helps to better fulfil these requirements. These noninvasive developments, their potential benefit as well as their limitations, together with new data on fractionation sensitivity of prostate cancer that may lead to shortened overall treatment times may be of interest for all physicians treating patients with prostate cancer.
The Search for Therapeutic Gain in Radiation Oncology Novel strategies in radiation oncology aim at increasing the therapeutic gain, i.e., to decrease side effects while maintaining cure rates, or to ...increase cure rates at the same level of complications. Over the years, physical and biological strategies have been developed to achieve this goal. The physical development led to the possibility of precise, computer-controlled beam application by using modern imaging techniques and three-dimensional treatment planning. Improved patient immobilization methods allow minimal safety distances, resulting in steep dose gradients when used together with isocentric multi-field techniques. These predominantly stereotactic irradiation techniques yield therapeutic gain towards the tumor surrounding normal tissue. A critical issue that determines the tolerance of radiation therapy are structures at risk within the target volume. Fractionation is a reliable method to exploit the differential potential for recovery of radiation-induced DNA damage in normal tissues. Radiogenetic strategies aim at the sensibilization of tumor cells by targeting specific characteristics like mutations of p53. The reverse idea, gene-therapeutic radioprotection of normal tissue, is under investigation.
4 Channel Codec Filter `SICOFI®-4 Tiefenbacher, M.; Caldera, P.; Hauptmann, J. ...
ESSCIRC '93: Nineteenth European Solid-State Circuits Conference,
1993-Sept., Letnik:
1
Conference Proceeding
A highly programmable four channel Codec Filter Chip for analog telephone subscriber lines is presented in this paper. As a great benefit for the user, but also a great challenge for the analog ...circuitry, the chip works with a single 5 Volt power supply and is fabricated in a 1μ CMOS technology. The circuit includes digital signal processing for filtering in the receive and transmit paths, impedance matching and transhybrid balancing filters, special hardware filter structures for decimation and interpolation at higher sampling rates and AD/DA converters. The circuit can easily be adapted to different country standards by different coefficient sets.
