Spectral discrimination of Cerenkov radiation in scintillating dosimeters

Radiation therapy accelerators require highly accurate dose deposition and the output must be monitored frequently and regularly. Ionization chambers are the primary tool for this control, but their size, their high voltage needed, and the correction needed for electrons make them unsuitable for use during patient treatment. We have developed a small (1-mm-diam and 1-mm-long active part), flexible, and water-equivalent dosimeter. It is suitable for photon and electron beams without corrections, and performs on line dose measurements. This detector is based on only one scintillating fiber and a CCD camera. A new signal processing is used to remove the effect of Cerenkov radiation background, which only requires a preliminary calibration. Central-axis depth-dose distribution comparisons have been achieved with standard ionization chambers, over a range from 8 to 25 MV photons and from 6 to 21 MeV electrons in order to validate this calibration. Results show a very good agreement, with less than 1% difference between the two detectors.     

Fractionation and biological characterization of Olea europea pollen extract

Preliminary fractionation of Olea european pollen extract has been performed. At least 10 antigenic fractions have been found by crossed electrophoresis. After Sephadex gel filtration, two fractions with a molecular weight of 160,000 and 65,000 have been obtained. The fractions were evaluated for allergenic activity by two in vitro techniques: polystyrene tube radioimmunoassay (PTRIA) and basophil degranulation test (BDT), and by skin tests. All tests indicated that the most reactive fractions were those in the 65,000 molecular weight peak. BDT has been shown to be a very reliable method as compared with histamine release and other parameters. Although common antigenic fractions have been found for Lollium perenne and O. europea, no cross-allergenicity has been shown by PTRIA inhibition.     

A comparative study of the treatment of vesicoureteral reflux in childhood: a review of a series of 636 refluxing units

A number of 411 pediatric patients (636 refluxing renal units) diagnosed as having vesicoureteral reflux (VUR) were evaluated in our Hospital between 1985 and 1997. All the patients were divided in two historic groups based on the therapeutical modalities employed. The children included in group A (between 1985 and 1995) were medically or surgically treated according to the grade of reflux. In the group B (between 1995 and 1997), the endoscopic treatment was added to previous. All cases underwent urine cultures, renal ultrasonography, voiding cystourethrography and isotopic gammagraphy with DMSA scan. In some patients were performed radionuclide renography with DTPA or MAG-3 to assess renal function. We consider that medical management is required in low grade reflux (I and II) but patients with high grade reflux (IV and V) clearly benefit from early ureteral surgical reimplantation (Cohen technique). In our series, patients with reflux grade III are treated endoscopically with Teflon or PDMS (polydimethylsiloxane) with resolution of reflux in 82-92% after first injection.     

Bladder hyporeflexia caused by vinca alkaloids

Presentation of one case of hyporreflexic bladder like a first step of neurotoxicity due to Vinca alkaloids. These drugs produces peripheral neuropathies as usual, but in some rare occasions they may affect to the autonomic nervous system with its effects in the bladder producing hyporreflexic. This disease reverts spontaneously after suppressing drugs.     

A hydrodynamic study of pleural drainage systems: some practical consequences

BACKGROUND: A pleural drainage system must be capable of efficiently evacuating the air or fluids from the pleural cavity so that adequate lung reexpansion can take place. The air flow and negative pressure of the system will depend on the particular design of each model. This experimental study analyzes the specifications and performance of the pleural drainage systems currently on the market. METHODS: Thirteen models of pleural drainage systems connected to wall suction were examined. The models were classified into the following three groups: dry systems; wet systems; and single-chamber systems. We determined the ambient air flow and the negative pressure generated according to the suction level. The components of each model are also described. RESULTS: Under normal conditions, dry (except for the Sentinel Seal; Sherwood Medical; Tullamore, Ireland), wet, and single-chamber systems reach similar air flow rates (17 to 30, 24 to 27, and 22 to 28 L/min, respectively). With higher wall suction levels, wet systems increase the air flow (26 to 49 L/min) but the negative pressure becomes unstable because of the water loss phenomenon, dry systems increase the air flow (29 to 50 L/min) without modifying the regulator pressure, and single-chamber systems also raise the air flow (45 to 51 L/min) but increase the negative pressure. When there is an air leak, dry systems (except for the Sentinel Seal) lose less negative pressure than the other systems. CONCLUSIONS: The functioning of these systems can be optimized only by applying a suitable wall suction level adjusted to each case. Although the three types of systems are capable of evacuating adequate air flow rates, the negative pressure and the capacity to maintain it in the presence of an air leak are different in each system. Being fitted with valves and not water compartments makes the dry systems the safest and the ideal for use when the patient has to be moved.