Chromosome analysis in patients with sarcoidosis

Chromosome analysis of lymphocytes from the peripheral blood of 20 patients with sarcoidosis and 10 healthy controls showed a significantly greater number of hypomodal cells among the patients. Two patients receiving systemic treatment with glucocorticoids had many chromosomal aberrations.     

An indexed atlas of digital mammograms for computer-aided diagnosis of breast cancer

Computer-aided diagnosis (cad) systems are being developed to assist radiologists in the interpretation of ambiguous mammographic features corresponding to possible signs of early breast cancer. Databases of digital mammograms are needed for testing such systems; we present an overview of a few such databases. Most databases are limited to single-exam sets of two or four mammograms on which the diagnosis was made, some ground-truth information related to the position of diagnostically significant mammographic features, and the diagnosis. We propose the design of a comprehensive, indexed atlas of digital mammograms. The design of an appropriate indexing scheme facilitates the implementation of content-based retrieval techniques needed for efficient access to and retrieval of relevant cases from the atlas. We also propose the use of mobile software agents for facilitating remote consultation of the atlas. Mobile agents can move between data sources such as the atlas and hospital repositories, perform computational tasks at each site, and return only relevant data to the user. These features reduce the computational requirements of the local computer system, bandwidth requirements, and overall network traffic. Proposed applications of the atlas include research, remote consultation, teaching, evaluation ofcad systems, and self-evaluation by radiologists.     

Numerical Optimization of an Active Voltage Controller for High-Power IGBT Converters

Feedback control of insulated gate bipolar transistors (IGBTs) in the active region can be used to regulate the device switching trajectory. This facilitates series connection of devices without the use of external snubber networks. Control must be achieved across the full active region of the IGBT and must balance a number of conflicting system goals including diode recovery. To date, the choice of control parameters has been a largely empirical process. This paper uses accurate device models and formalized optimization procedures to evaluate IGBT active voltage controllers. A detailed optimization for the control of IGBT turn-on is presented in this paper     

Failures after operation for skeletal metastatic lesions of long bones

This study was based on 192 patients treated surgically for 228 metastatic lesions of the long bones from 1986 through 1995. The survival rate was 0.3 at 1 year after surgery. The surgical treatment consisted of resection and reconstruction of the involved bone (18), intralesional curettage (133), or stabilization only (77). Reconstruction was achieved by an endoprosthesis in 54 cases, by an osteosynthetic device in 162, by cement only in 10. In two cases no reconstruction was performed. The local failure rate was 11% and the median time to failure was 8 months. Local failure was most frequent in patients with kidney cancer (24%) and in diaphyseal and distal femoral lesions (20%). Among 162 operations involving osteosynthetic devices, 22 (14%) were failures as compared with one of 54 (2%) endoprostheses. Sixty percent of the patients received preoperative or postoperative radiotherapy. Five of the six patients who had surgery for local tumor progression had not received radiotherapy. Eight of 10 nonunions and all five patients who developed a stress fracture had been treated with radiotherapy. It is concluded that endoprosthetic reconstructions are preferable to osteosynthetic devices. The skeletal complications associated with radiotherapy may be circumvented by the use of endoprostheses.     

150km optical fibre transmission network experiment with 2Gbit/s throughput

Optical time-division multiplexing is considered for synchronous gigabit/s long-distance ransmission networks. Experimental results are presented for a 150 km fibre network of 2 Gbit/s capacity. The problem of differential fibre propagation delay variations is addressed with signal processing developed for the implementation of closed-loop feedback control.     

The membrane protein alkaline phosphatase is delivered to the vacuole by a route that is distinct from the VPS-dependent pathway

Membrane trafficking intermediates involved in the transport of proteins between the TGN and the lysosome-like vacuole in the yeast Saccharomyces cerevisiae can be accumulated in various vps mutants. Loss of function of Vps45p, an Sec1p-like protein required for the fusion of Golgi-derived transport vesicles with the prevacuolar/endosomal compartment (PVC), results in an accumulation of post-Golgi transport vesicles. Similarly, loss of VPS27 function results in an accumulation of the PVC since this gene is required for traffic out of this compartment. The vacuolar ATPase subunit Vph1p transits to the vacuole in the Golgi-derived transport vesicles, as defined by mutations in VPS45, and through the PVC, as defined by mutations in VPS27. In this study we demonstrate that, whereas VPS45 and VPS27 are required for the vacuolar delivery of several membrane proteins, the vacuolar membrane protein alkaline phosphatase (ALP) reaches its final destination without the function of these two genes. Using a series of ALP derivatives, we find that the information to specify the entry of ALP into this alternative pathway to the vacuole is contained within its cytosolic tail, in the 13 residues adjacent to the transmembrane domain, and loss of this sorting determinant results in a protein that follows the VPS-dependent pathway to the vacuole. Using a combination of immunofluorescence localization and pulse/chase immunoprecipitation analysis, we demonstrate that, in addition to ALP, the vacuolar syntaxin Vam3p also follows this VPS45/27-independent pathway to the vacuole. In addition, the function of Vam3p is required for membrane traffic along the VPS-independent pathway.     

Synchrotrons for hadron therapy: Part I

The treatment of cancer with accelerator beams has a long history with betatrons, linacs, cyclotrons and now synchrotrons being exploited for this purpose. Treatment techniques can be broadly divided into the use of spread-out beams and scanned ‘pencil’ beams. The Bragg-peak behaviour of hadrons makes them ideal candidates for the latter. The combination of precisely focused ‘pencil’ beams with controllable penetration (Bragg peak) and high, radio-biological efficiency (light ions) opens the way to treating the more awkward tumours that are radio-resistant, complex in shape and lodged against critical organs. To accelerate light ions (probably carbon) with pulse-to-pulse energy variation, a synchrotron is the natural choice. The beam scanning system is controlled via an on-line measurement of the particle flux entering the patient and, for this reason, the beam spill must be extended in time (seconds) by a slow-extraction scheme. The quality of the dose intensity profile ultimately depends on the uniformity of the beam spill. This is the greatest challenge for the synchrotron, since slow-extraction schemes are notoriously sensitive. This paper reviews the extraction techniques, describes methods for smoothing the beam spill and outlines the implications for the extraction line and beam delivery system     

Severe gastrointestinal hemorrhage due to Mycobacterium avium complex in a patient receiving immunosuppressive therapy

Intense immunosuppressive therapy is used frequently for treatment of systemic vasculitides, collagenoses, rapidly progressive glomerulonephritis, and after organ transplantation. Numerous serious treatment-related side effects include localized or disseminated opportunistic infections, and require careful monitoring of immunosuppressed patients. Gastrointestinal infections with Mycobacterium avium complex (MAC) or other nontuberculous mycobacteria have been previously identified in HIV seropositive patients only. We now report the first case of an HIV seronegative patient who received immunosuppressive therapy for rapidly progressive glomerulonephritis. The patient presented with severe lower gastrointestinal bleeding and was diagnosed to have ulcerative colitis due to infection with MAC. The patient recovered promptly after administration of antimycobacterial therapy. MAC infection should be included in the differential diagnosis of gastrointestinal bleeding in all immunodeficient patients. The significance of repeated colonoscopy to obtain multiple biopsy specimens with histological examination for foam cells and specific staining for acid-fast organisms is emphasized.