Search PubMed⌕ Search

Biomedical subjects

P Fava

Publications and source records attributed to P Fava.

At least 19 recordsLinked to original sources
PubMed2003

Assessment of the risk of physical contamination of bread packaged in perforated oriented polypropylene films: measurements, procedures and results.

Perforated films used for wrapping factory-manufactured bread must permit a very rapid and intense moisture exchange because the packaging operation is carried out while the bread is still warm (about 80 degrees C) and releasing a high quantity of moisture. The open surface of the wrapping of those products sold in self-service retail outlets generates suspicion about possible contamination of bread not properly handled by the consumers and a better knowledge of the performance of these materials seems appropriate. Using two different approaches, the geometrical characteristics and perforation pattern of 13 different oriented polypropylene (OPP) films representative of the whole European market were assessed objectively. All the measured parameters (density of perforation, hole dimension, open surface, etc.) showed asymmetric distributions, i.e. with averages close to the lowest figures. Similar asymmetric distribution was shown from the 'risk of contamination' by artificial sweat and saliva: an empirical parameter which was measured by procedures developed to simulate the worst possible case of inappropriate manipulation of the packed bread. Good correlation was found between the 'risk of contamination' and both the 'hole surface' (mm(2)) and the 'open surface' (percentage holes surface/film surface), leading to the conclusion that the proposed procedures could represent useful methodologies for assessment of such a particular case of possible food contamination.

Bread↗
PubMed2000

An alternative mantle irradiation technique using 3D CT- based treatment planning for female patients with Hodgkin's disease.

PURPOSE: For female patients, radiotherapy treatment for Hodgkin's disease invariably results in the irradiation of breast tissue that may lead to radiation induced secondary cancers. The risk for secondary breast cancer is correlated with dose. We have developed a technique in an attempt to increase breast sparing during mantle field irradiation for female patients. MATERIAL AND METHODS: To minimize the irradiated breast volume, a virtual simulation technique making use of a Styrofoam breast immobilization board has been developed whereby the patient lies prone with the breasts positioned in grooves within the board. The breast position is adjusted using Styrofoam wedges, and breast placement is verified using an AP CT-pilot view. A CT scan of the neck and thoracic regions is taken, and the lymph nodes, breast volume and critical structures are outlined. Virtual simulation of the mantle fields (typically AP/PA isocentric beams) is performed, and beam blocks are drawn on the digitally reconstructed radiographs (DRR) generated by the virtual simulation package. The shielding is designed to allow adequate margins around the lymph nodes while maximizing shielding of the lung and breast tissues. The para-aortic fields are also easily determined through virtual simulation, where multi-planar reconstructions (MPR) and 3D renderings of the patient's CT data are used to determine the field limits and beam gaps. In addition to allowing for the geometric optimization of the positioning of the breasts under the lung shields, the virtual simulation technique provides the necessary information for a 3D dosimetric analysis, including dose-volume histograms (DVHs) of the irradiated breast volume. RESULTS: The 3D breast sparing technique was qualitatively and quantitatively compared to non-CT-based techniques and other 3D techniques currently available to assess the protection of the breasts. In a preliminary analysis, virtual simulation images (DRRs, 3D rendering and multi-planar reconstruction) demonstrated the advantage of using the breast sparing technique. A further analysis of DVHs showed a reduction of at least 50% in the volume of breast tissue irradiated when using the breast positioning board and virtual simulation as compared to the conventional simulation techniques where a breast immobilization board was not used. CONCLUSIONS: The use of a breast immobilization board and of a virtual simulation technique is recommended for the planning and treatment of female patients with Hodgkin's disease. DVH analysis has shown that this leads to a decrease in the volume of breast irradiated. It is hoped that this approach will reduce the risk of secondary breast malignancies in female patients with Hodgkin's disease.

Breast↗
PubMed1999

Study of diffusion through LDPE film of Di-n-butyl phthalate.

The apparent diffusion coefficients (D) across a PE-LD film of Di-n-butyl phthalate (DnBP) dissolved in isooctane and ethanol, were calculated in different ways and compared. DnBP, a common plasticizer of plastics and printing inks, may be a possible contaminant of flexible packaging and PE-LD is the most common food-contacting polymer. To perform diffusion measurements, small plastic sachets filled with solutions of the contaminant were used at three different temperatures. The D coefficients of the two solvents and dissolved DnBP were calculated using the lag time method, a formula taking into account the molar weight and absolute temperature, and an equation based on the initial concentration and the amounts migrated after subsequent times. The results demonstrated great solvent interference in the plasticizer diffusion across polyethylene; in particular as far as isooctane is concerned, a remarkable co-diffusion of both the plasticizer and the non-polar solvent must be assumed. Isooctane quickly penetrates PE-LD but ethanol also diffuses across PE-LD, although at a greatly reduced speed. These facts must be considered for realistic prediction of migration or effectiveness of the functional barrier.

Dibutyl Phthalate↗
PubMed1993

Accelerated fractionation in inoperable non-small cell lung cancer. A phase I/II study.

BACKGROUND: A prospective, single-treatment-arm, Phase I/II trial was performed to determine the tumor response to an accelerated regimen and assess the feasibility and toxic effects of this approach in patients with inoperable non-small cell lung cancer (NSCLC). METHODS: Thirty-seven previously untreated patients with inoperable NSCLC who had no evidence of metastatic disease entered the study. All patients were able to walk and had disease that was measurable or assessable. Patients with palpable supraclavicular disease and weight loss were also eligible. Radiation therapy consisted of an altered fractionation regimen with a concomitant boost technique. The original lung volume received a dose of 40 Gy in 20 daily fractions to the computerized axial tomography (CT)-defined primary tumor and mediastinal nodes. The boost dose (10 Gy) was administered concomitantly with the last five fractions of the original volume treatments, with an interfraction interval of 6-8 hours. The maximal allowed dose to the cord was 46 Gy. RESULTS: At a median follow-up of 36 months, complete response was achieved in 29% (9 of 31) of the patients and a partial response in 42% (13 of 31). The overall survival rate at 36 months was 10% (median survival time, 8 months). Survival rates were 25%, 8%, and 0% for the complete responders, partial responders, and nonresponders, respectively. Local failure alone was observed in 35.5% of all patients, local and distant failure in 42%, and distant failure only in 13%. Treatments were well tolerated, and all patients were able to complete the planned regimen. Grade 1 and 2 esophagitis occurred in 65% and 26% of the patients, respectively. The clinical condition of two patients (6%) was compatible with radiation pneumonitis. Moist desquamation of the skin occurred in two patients, but most had either mild (55%) or moderate (19%) skin erythema. Late complications have been limited to radiologically detected lung fibrosis. CONCLUSIONS: The accelerated fractionation schedule used in this trial was well tolerated with shortening of overall treatment time. Local tumor control and overall survival are similar to those resulting from conventional fractionation without an increase in normal tissue effects. These results are encouraging, and additional studies testing higher tumor doses are warranted.

Aged↗
PubMed1990

Tolerance and efficacy of parenterally administered penicillin-streptomycin and orally administered amoxicillin or penicillin V for prophylaxis of experimentally induced streptococcal endocarditis.

A regimen of a single intramuscular dose of penicillin G-streptomycin was compared with regimens of three oral doses of amoxicillin and two oral doses of penicillin V to prevent Streptococcus sanguis endocarditis in rabbits with experimentally induced valvular heart lesions. Challenge doses of 10(4), 10(6), and 10(8) CFU of a strain of S. sanguis highly tolerant to penicillin and amoxicillin were used. The combination of penicillin and streptomycin was the only regimen tested that provided full protection even against the highest inoculum concentration. A single oral dose of penicillin V (36 mg/kg) or amoxicillin (50 mg/kg), two oral doses of penicillin V (36 and 18 mg/kg with a 7-h interval between doses), or six oral doses of amoxicillin (50 mg/kg followed by 8.5 mg/kg at 8-h intervals) protected recipients of the lowest inoculum concentration; protection diminished with increasing inocula. In contrast, administration of two high oral doses of amoxicillin (50 mg/kg) with a 10-h interval between doses provided full protection against challenge doses of 10(4) and 10(6) CFU, preventing endocarditis in 10 (66%) of 15 recipients of 10(8) CFU. All regimens evaluated were highly effective in preventing endocarditis when rabbits were challenged with 10(4) CFU. The combination of penicillin and streptomycin was the best regimen tested. Administration of two high oral doses of amoxicillin (50 mg/kg) with a 10-h interval between doses led to significantly fewer infections when compared with the other oral regimens when rabbits were challenged with 10(6) and 10(8) CFU.

Amoxicillin↗
PubMed1988

Density-related changes of potassium (86Rb) uptake by amphibian endothelial cells.

Potassium influx has been investigated in XTH-2 cells, a line derived from tadpole heart endothelia. In this line, the density at which the cultures become confluent is clearly separated from the density at which growth arrest takes place. Density-related changes in K+ influx were monitored by determining the uptake of 86Rb into well adhering cells kept in culture medium. The main observations were 1) 86Rb uptake is highest in single cells, and on confluency it reaches a low level, which is kept constant at higher cell density regardless of whether the cultures are stationary or still in logarithmic growth phase; 2) the relative amount of 86Rb taken up via the Na+ -K+ -2Cl- cotransport pathway and via the Na+/K+ pump changes from low cell density to confluent cultures; 86Rb uptake of single cells is nearly insensitive to ouabain, a maximum of ouabain sensitivity is reached around confluency, whereas piretanide-sensitive 86Rb uptake is highest in single cells and seems to reach a minimum at the onset of confluency; 3) the variations in Na+/K+ pumping rate reflect neither differences in the amount of enzyme present nor changes in enzyme repartition between apical and basolateral plasma membranes; they seem to result from either "masking" or "unmasking" of the enzyme; 4) no alterations in K+ uptake occur that would be characteristic of the "stationary growth phase." The only changes that seem to be related to arrest of proliferation are concerned with the Na+/K+-ATPase, which achieves an extraordinary susceptibility to stimulation by monensin and exhibits an increase in PNPPase activity.

Animals↗
PubMed1988

[Priapism induced by heparin. A more serious prognosis?].

Between 1973 and 1985, 31 patients were treated in the Urology Department of La Pitié hospital for priapism. Analysis of the aetiologies, determined in 25 cases, revealed a particularly high incidence of heparin as an aetiological factor for priapism. Surgical treatment was proposed in 28 patients. Independently of the type of surgical treatment performed and with a comparative preoperative delay, priapism as a complication of heparin therapy appears to be functionally more severe than priapism due to other aetiologies. Although the frequency, mechanism and prognosis of this complication of heparin therapy remain poorly understood, analysis of the 10 cases in this series and a review of the literature nevertheless provide certain answers.

Adult↗
PubMed1987

Efficacy of orally administered penicillin V for prophylaxis of experimentally induced streptococcal endocarditis.

Four oral penicillin V regimens were compared for the ability to prevent Streptococcus sanguis infection of experimentally induced valvular heart lesions in rabbits. Challenge doses of 10(4), 10(6), and 10(8) CFU of a penicillin-susceptible strain of S. sanguis were used in this study. Measured by recovery of test organisms from endocardial lesions, the lowest-concentration inoculum was infective for 53% of the recipients; the higher-concentration inocula were infective for all recipients. A single-oral-dose penicillin V regimen (36 mg/kg of body weight) prevented endocarditis when rabbits were challenged with 10(4) CFU, but protection diminished with increasing inoculum concentrations. In contrast, addition of a second penicillin V dose (18 mg/kg of body weight) administered with a 7-h interval between doses achieved fully effective prophylaxis against even the highest inoculum tested (10(8) CFU). A repeated set of experiments in which half the dose of penicillin V was administered showed significantly reduced protection against S. sanguis endocarditis.

Adult↗
PubMed1986

Comparative capacity of orally administered amoxicillin and parenterally administered penicillin-streptomycin to protect rabbits against experimentally induced streptococcal endocarditis.

A single-intramuscular-dose immunization regimen with a penicillin G-streptomycin combination was compared with three oral-dose amoxicillin regimens for the capacity to prevent Streptococcus sanguis infections of experimentally induced valvular heart lesions in rabbits. Challenge doses of 10(4), 10(6), and 10(8) CFU of a strain of S. sanguis equally susceptible to penicillin and amoxicillin were used in this study. Measured by recovery of test organisms from endocardial lesions, the lowest concentration of these inocula was infective for 60% of the recipients; the two higher-concentration inocula were infective for all recipients. The penicillin G-streptomycin combination provided complete protection against infection with inocula of all sizes. A single-oral-dose amoxicillin regimen (50 mg/kg of body weight) prevented endocarditis when rabbits were challenged with 10(4) CFU, but protection diminished with increasing inoculum concentrations. Similar results were achieved when five oral doses of amoxicillin (8.5 mg/kg of body weight) added at 8-h intervals were included in the single-oral-dose regimen. In contrast, when rabbits received two oral doses of amoxicillin (50 mg/kg of body weight) with a 10-h interval between doses, prophylaxis was fully effective with even the highest inoculum concentration.

Amoxicillin↗
PubMedDate not supplied

Minimizing the residual oxygen in modified atmosphere packaging of bakery products.

The total elimination of air represents a serious hurdle in modified atmosphere packaging of bakery products, due both to the high spin-rates of the packaging lines and, particularly, to the typical texture of bakery products which retain large quantities of air inside their porous structure. Simulating the gas-flushing modified atmosphere packaging with laboratory equipment and measuring the oxygen concentration directly inside bread rolls, by means of a gas analyser connected with the internal portion, it was possible to follow the rate of atmosphere substitution, evaluating the effects of different baking treatments (7, 12 and 23 min at 230 degrees C) and the role played by different gases (nitrogen, argon, helium, nitrous oxide and carbon dioxide). The oxygen content inside the products, plotted versus time, led to typical logistic 'dose-response' curves which made it possible to forecast the time needed to reach established values of residual oxygen concentration and to emphasize the effects of the different conditions used. The gas properties particularly affected the rate of oxygen substitution and the less water-soluble was the gas, the faster was the oxygen reduction; the larger was the gas molecule, the slower was the process. Also baking time was shown to have, to a different extent, some measurable effects on the rate of oxygen substitution and hence, its optimization as well as the choice of gas mixture can contribute to improve modified atmosphere packaging of bakery products.

Argon↗
PubMedDate not supplied

[Occlusal adjustment].

Explore the source record for details and available documents.

Dental Occlusion, Balanced↗