Monte Carlo dose calculations using MCNP4C and EGSnrc/BEAMnrc codes to study the energy dependence of the radiochromic film response to beta-emitting sources.

The energy dependence of the radiochromic film (RCF) response to beta-emitting sources was studied by dose theoretical calculations, employing the MCNP4C and EGSnrc/BEAMnrc Monte Carlo codes. Irradiations with virtual monochromatic electron sources, electron and photon clinical beams, a (32)P intravascular brachytherapy (IVB) source and other beta-emitting radioisotopes ((188)Re, (90)Y, (90)Sr/(90)Y,(32)P) were simulated. The MD-55-2 and HS radiochromic films (RCFs) were considered, in a planar or cylindrical irradiation geometry, with water or polystyrene as the surrounding medium. For virtual monochromatic sources, a monotonic decrease with energy of the dose absorbed to the film, with respect to that absorbed to the surrounding medium, was evidenced. Considering the IVB (32)P source and the MD-55-2 in a cylindrical geometry, the calibration with a 6 MeV electron beam would yield dose underestimations from 14 to 23%, increasing the source-to-film radial distance from 1 to 6 mm. For the planar beta-emitting sources in water, calibrations with photon or electron clinical beams would yield dose underestimations between 5 and 12%. Calibrating the RCF with (90)Sr/(90)Y, the MD-55-2 would yield dose underestimations between 3 and 5% for (32)P and discrepancies within +/-2% for (188)Re and (90)Y, whereas for the HS the dose underestimation would reach 4% with (188)Re and 6% with (32)P.

[The new magnetic therapy TAMMEF in the treatment of simple shoulder pain]. / Il nuovo sistema di magnetoterapia TAMMEF nel trattamento della spalla dolorosa semplice.

AIMS: Numerous studies have demonstrated the utility of extremely low frequencies (ELF) electromagnetic fields in the treatment of pain. Moreover, the effects of these fields seems to depend on their respective codes (frequency, intensity, waveform). In our study we want to assess the effects of the TAMMEF (Therapeutic Application of a Musically Modulated Electromagnetic Field) system, whose field is piloted by a musical signal and its parameters (frequency, intensity, waveform) are modified in time, randomly varying within the respective ranges, so that all possible codes can occur during a single application. PATIENTS AND METHODS: Sixty subjects, affected by shoulder periarthritis were enrolled in the study and randomly divided into three groups of 20 patients each: A exposed to TAMMEF, B exposed to ELF, C exposed to a simulated field. All subjects underwent a cycle of 15 daily sessions of 30 minutes each and a clinical examination upon enrollment, after 7 days of therapy, at the end of the cycle and at a follow-up 30 days later. RESULTS: All the patients of groups A and B completed the therapy without the appearance of side effects: they presented a significant improvement of the subjective pain and the functional limitation, which remained stable at the follow-up examination. In group C, there was no improvement of the pain symptoms or articular functionality. CONCLUSIONS: This study suggests that the TAMMEF system is efficacious in the control of pain symptoms and in the reduction of functional limitation in patients with shoulder periarthritis. Moreover, the effects of the TAMMEF system cover those produced by the ELF field.

A study of quality of bremsstrahlung spectra reconstructed from transmission measurements.

A numerical method for the reconstruction of bremsstrahlung spectra has been applied to the analysis of simulated data. The method is found to be reliable in reconstructing x-ray spectra of maximum energy up to 10 MeV. Measurements of aluminum transmission data carried out for five linear accelerators have also been analyzed by this method to determine the fractional energy fluence. The values of the Spencer-Attix water/air stopping power ratio, SS.A. w,air, reported as a function of the ratios TPR20 10, are in good agreement with computed results. Quality index values were correlated to mean incident energies of x-ray beams used in radiotherapy. The experimental setup has also provided information regarding the softening effect on the off-axis beam, which can be used in clinical computer dosimetry to correct conventional zero field size tissue maximum ratio.

Efficacy and safety of a musically modulated electromagnetic field (TAMMEF) in patients affected by knee osteoarthritis.

OBJECTIVE: Numerous studies have demonstrated the utility of extremely low frequencies (ELF) electromagnetic fields in clinical practice. Moreover, the effects of these fields seems to depend on their respective codes (frequency, intensity, waveform). In our study we want to value the effects of the TAMMEF (Therapeutic Application of a Musically Modulated Electromagnetic Field) system, which field is piloted by a musical signal. METHODS: Ninety subjects, affected by primary osteoarthritis of the knee, were enrolled in the study and randomly divided into three groups of 30 patients each: A exposed to TAMMEF, B exposed to ELF, C exposed to a simulated field. All subjects underwent a cycle of 15 daily sessions of 30 minutes each and a clinical examination upon enrolment, after 7 days of therapy, at the end of the cycle and at a follow-up 30 days later: RESULTS: All the patients of groups A and B completed the therapy without the appearance of side effects: they presented a significant improvement of the subjective pain and the functional limitation, which remained stable at the follow-up examination. In group C, there was no improvement of the pain symptoms or articular functionality. CONCLUSIONS: This study suggests that the TAMMEF system is efficacious in the control of pain symptoms and in the reduction of functional limitation in patients with knee osteoarthritis. Moreover, the effects of the TAMMEF system cover those produced by the ELF field.

Helicobacter pylori infection and infertility.

OBJECTIVE: To determine (1) the prevalence of Helicobacter pylori infection in male and female patients with reproductive disorders and controls; (2) the presence of anti-H. pylori antibodies in samples of follicular fluid, vaginal secretions and sperm; and (3) the existence of a structural homology between a major spermatozoa protein, tubulin, and H. pylori proteins. PATIENTS AND METHODS: Serum samples from 167 patients with infertility and 837 age- and gender-matched controls (blood donors) were examined by enzyme-linked immunosorbent assay (ELISA) and Western blotting to determine the seropositivity for H. pylori infection. The presence of anti-H. pylori antibodies in samples of follicular fluid, vaginal secretions and sperm was determined using the same techniques. The possible cross-reactivity with spermatozoa of anti-H. pylori hyperimmune sera and human antibodies was studied by immunofluorescence. The N-acid homology of human tubulin with the principal H. pylori proteins was assayed by the WU-blastp program available on the Internet. RESULTS: The prevalence of infection was significantly higher in patients than controls (49.1% v. 33.5%, P < 0.001). Follicular fluids from infected patients contained specific antibodies in all cases, sperm samples in about 50% of cases, and vaginal secretions in a minority of cases. Sera to H. pylori whole antigens and VacA reacted with the tails and the pericentriolar area of human spermatozoa (which are rich in tubulin); sera to urease and heat-shock protein (Hsp) did not. Follicular fluids with anti-H. pylori antibodies immune reacted with spermatozoa. A linear homology was found between beta-tubulin and three H. pylori proteins, flagellin, VacA and CagA. CONCLUSIONS: H. pylori infection may increase the risk of developing reproductive disorders or worsen the clinical expression of this syndrome.

CagA-positive Helicobacter pylori infection may increase the risk of food allergy development.

The aim of this study was to test whether patients with symptomatic food allergy and significant levels of immunoglobulin E (IgE) to alimentary antigens were more likely infected by H. pylori, especially by strains expressing the CagA protein, with respect to controls. A group of 38 patients with symptomatic food allergy and 53 age-matched controls were examined serologically for H. pylori infectious status, and for CagA seropositivity. IgE to alimentary allergens were measured by a commercial kit. The prevalence of H. pylori infection in patients with food allergy and controls was similar (42.1%, and 48.3%, respectively). However, anti-CagA antibodies in H. pylori-infected persons were detected in 62.5% of patients with food allergy, and 28% of controls (P = 0.030, odds ratio = 4.29). The mean level of IgE to the most common alimentary antigens in serum samples from infected patients with anti-CagA antibodies was significantly higher than in CagA-negative infected patients: 3.28 kU/L (SD 3.93), vs. 1.99 kU/L (SD 1.53), P = 0.002, 95% confidence interval = 0.61 to 2.53). Infection by CagA-positive H. pylori increases the risk of developing food allergy.

The infection by Helicobacter pylori strains expressing CagA is highly prevalent in women with autoimmune thyroid disorders.

UNLABELLED: H. pylori infection is putatively associated with extra-digestive disorders and may also play a role in the development of autoimmune thyroid diseases (ATD). It was recently found that monoclonal antibodies to an H. pylori strain with cagA-positivity reacted with follicular cells of the thyroid gland, and that an H. pylori organism possessing the cag pathogenicity island carried a gene encoding for an endogenous peroxidase. The aims of this study was (1); To ascertain whether the infection by strains endowed with an increased inflammatory potential (those expressing CagA) could further enhance the risk of developing ATD (2); To verify the possible existence of an immune cross-reactivity between autoantibodies to peroxidase and thyroglobulin and H. pylori antigens (3). To establish whether thyroid colloid antigens could cross-react with an anti-H. pylori serum. The study was partly designed retrospectively. We examined 41 consecutive women with ATD, and, as a control, 33 consecutive age- and socio-economic class-matched women without autoimmune thyroid disorders, living in the same area as patients, occurred at the same institution in the same period (six months). Both patients and controls were examined serologically for H. pylori infection and CagA status by Western blotting. Some serum samples were absorbed with H. pylori to determine whether the antibody levels decreased. Colloid proteins were resolved electrophoretically and matched with a hyperimmune serum raised in rabbits against a CagA-positive H. pylori. Thirty-two patients (78.0%) tested seropositive for H. pylori infection, vs. 16 controls (48.4%) (P = 0.008, OR = 3.78, RR = 1.61). The prevalence of anti-CagA antibodies was 71.8% in infected patients, and 50% in infected controls (P = 0.161, n.s.). The overall prevalence of infection by CagA-positive H. pylori was significantly higher in patients with ATD (23/41, or 56.0%) than that in controls (8/33, or 24.2%) (P = 0.006, OR = 3.99, RR = 2.31). The other tests gave negative or inexplicable results. IN CONCLUSION: CagA-positive H. pylori infection increases the risk of ATD development.

Stereotactic irradiation therapy. Physical and dosimetric problems.

In stereotactic irradiation by external beams there are many problems involved with dosimetry of small fields, three-dimensional representation of dose distribution, radiobiological involvement of tissue response to total dose and fractionation. Dosimetric problems arise by critical dimension of dosimetric chambers and by difficulties of films calibration. The amount of data required for a correct three-dimensional simulation of isodose curves, tumor and anatomical structures require a very speed computer system, sophisticated computer graphic techniques and calculation algorithm. By use the linear quadratic model of cell survival, maps of combined dose and biological effect (isoeffect curves) are also obtained.

Risk factors for acquiring Helicobacter pylori infection in a group of Tuscan teenagers.

Risk factors for acquiring Helicobacter pylori infection include hygienic, social, and environmental conditions. Some of these conditions usually change over time. We therefore investigated the existence of risk factors in a group of teenagers living in a place with the same environmental characteristics, in which hygienic and crowding conditions have not changed significantly in the last 20 years. A group of 164 students, mostly borne in 1977, attending four different schools, were examined serologically for H. pylori infection and CagA status. The importance of the risk factors for the transmission of the infection were evaluated by the chi2 test. P values <0.05 were considered significant. Twenty-two students (13.4%) were H. pylori seropositive. Students attending teachers' college and high school of arts were infected significantly more often than those attending high school (P = 0.011 and P = 0.012, respectively). Students who smoked and students whose parents had a manual job had an increased risk of acquiring the infection (P = 0.002, and P = 0.036, respectively). Crowding conditions and the presence of domestic animals were close to being statistically significant. Other factors, such as gender, number of bathrooms and bedrooms, sharing the bed with adults as a child, presence of a sexual partner, and a family history of peptic ulcer and gastric cancer, did not increase the risk of infection. The prevalence of seropositivity for CagA was similar in the various risk groups. Manual job of parents and smoking were the most important factors for acquiring H. pylori infection.

[Usefulness of online bibliographic research in biomedical research, with an application to the epidemiologic study of genetic osteopathy]. / Utilità della ricerca bibliografica online nella ricerca biomedica, con applicazione allo studio epidemiologico delle osteopatie genetiche.

The bibliographic research online is an useful means of recovering information in all the subjects, particularly in the field of biomedicine. In fact, this instrument allows researchers to get information in a rapid, complete and up-to-date way. The aim of the present review is to describe the usefulness of the bibliographical research online in the field of the genetic osteopathies. These are rare disorders: so, their own rarity makes the bibliographical research online necessary to carry out a large and effective comparison of experiences. The obtained results are amply reported in the manuscript. For instance, we verified that chondrodysplasias are the diseases most represented in the literature, while melorheostosis the disorder less mentioned. Moreover, we evidenced that some hereditary disorders of connective tissue, such as Marfan's syndrome, osteogenesis imperfecta and Ehlers-Danlos syndrome, are strongly influenced by race, sex and age.

[Internet: a fundamental tool for the retrieval of the information useful for medical research and health care in oncology]. / Internet: uno strumento essenziale nel recupero dell'informazione utile per la ricerca e l'assistenza oncologica.

Internet represents an essential aid for the professional updating of physicians and researches. Also for the research and therapy in oncology, Internet provides important such as bibliographic data, trials and guidelines with full text, as well as epidemiologic and statistical data. Some of the most authoritative sites are indicated.

[Is viscoelastic the corneal tissue?]. / Il tessuto corneale è viscoelastico?

PURPOSE: To compare the known viscoelastic properties of soft tissues with singular published observations on the behaviour of corneal tissue. MATERIALS AND METHODS: The behaviour of the maxwellian element, typical viscoelastic biomechanical model, is compared with that of various previously studied soft tissues of animals. The same comparison can be made between stress-strain curves of riboflavin and UVA treated and untreated strips of human and porcine corneal tissue, stretched at constant velocity, from the literature. RESULTS: The asymptotic stress-strain curves of the various soft tissues previously examined could be faithfully simulated by the Maxwell viscoelastic element. The exponential stress-strain curves of samples of corneal tissue were clearly different. CONCLUSIONS: The observed divergence demonstrates incompatibility between the alleged behaviour of corneal tissue and the viscoelastic properties attributed to it. Thus there are two possibilities: either corneal tissue is viscoelastic and the experiment showing exponential behaviour suffers from some technical problem, or the data is correct and corneal tissue is not viscoelastic. In either case further research is necessary for correct interpretation of the mechanism of cross-linking and for consequent therapeutic choices.

Keratoconus, cross-link-induction, comparison between fitting exponential function and a fitting equation obtained by a mathematical model.

With reference to experimental data in the literature, we present a model consisting of two elastic elements, conceived to simulate resistance to stretching, at constant velocity of elongation, of corneal tissue affected by keratoconus, treated with riboflavin and ultraviolet irradiation to induce cross-linking. The function describing model behaviour adapted to stress and strain values. It was found that the Young's moduli of the two elastic elements increased in cross-linked tissues and that cross-linking treatment therefore increased corneal rigidity. It is recognized that this observation is substantially in line with the conclusion reported in the literature, obtained using an exponential fitting function. It is observed, however, that the latter function implies a condition of non-zero stresses without strain, and does not provide interpretative insights for lack of any biomechanical basis. Above all, the function fits a singular trend, inexplicably claimed to be viscoelastic, with surprising perfection. In any case, using the reported data, the study demonstrates that a fitting equation obtained by a modelling approach not only shows the evident efficacy of the treatment, but also provides orientations for studying modifications induced in cross-linked fibres.

Prevalence of Helicobacter pylori infection in male patients with osteoporosis and controls.

Cytokines that regulate bone turnover (tumor necrosis factor-alpha, interleukin-6, etc.) may influence the pathogenesis of skeleton disorders, such as osteoporosis. Since Helicobacter pylori infection increases the systemic levels of inflammatory cytokines, we investigated the possibility that this infection increases the risk of developing osteoporosis and affects the bone metabolism in a group of male patients with osteoporosis. We examined 80 osteoporotic male patients and 160 controls for serum antibodies to H. pylori and the CagA protein and determined, in patients alone, the most important biochemical and instrumental parameters of the disease. Fifty-one patients (63.7%) and 107 controls (66.8%) were seropositive for H. pylori infection (nonsignificant); 30 infected patients (58.8%) and 43 infected controls (40.1%) were positive for anti-CagA antibodies (P = 0.028; OR = 2.13). Levels of estradiol in infected CagA-positive patients were significantly lower than in infected CagA-negative patients (28.5 [SD = 10.18] vs. 39.5 [SD = 14.50] pg/ml; P = 0.002) and uninfected patients (35.2 [SD = 12.7] pg/ml; P = 0.028). Levels of urinary cross-laps(a marker of bone resorption) were increased in patients infected by CagA-positive strains compared to patients infected by CagA-negative strains (282.9 [SD = 103.8] vs. 210.5 [SD = 150.1]microg/mmol; P = 0.048) and uninfected patients (204.3 [SD = 130.1] microg/mmol; P = 0.016). Differences among uninfected and infected patients, independent of CagA status, were observed for other markers of bone turnover, but they did not reach statistical significance. Infection by CagA-positive H. pylori strains is more prevalent in men with osteoporosis, who show reduced systemic levels of estrogens and increased bone turnover. H. pylori infection by strains expressing CagA may therefore be considered a risk factor for osteoporisis in men.

[Dosimetry problems of radiotherapy with electron fields of small dimension or partially shielded]. / Problemi dosimetrici nella radioterapia con campi di elettroni di dimensioni piccole o parzialmente schermati.

In radiotherapy in many clinical cases it is necessary to employ electron beams of small dimensions and/or shielded in order to have shaped fields. It is well known that percentage depth dose and output depend on the energy, on the field dimensions and on the collimation system. In order to evaluate separately the influence of these factors measurements were performed with electron beams of nominal energy from 6 to 14 MeV, of a linear accelerator Philips SL/75. Measurements were performed in standard dimension phantoms and in a small perspex phantom, 3 cm diameter. The values obtained in this small phantom were compared with the ones obtained for the same diameter collimator in order to have information on effect of missing lateral scatter equilibrium. Other measurements for an applicator, open and partially shielded, were performed. The results of these measurements are shown in graphics. Data show that the percentage depth dose ionization curves at fixed energy depend on the collimator linear dimension in particular, when these dimensions are smaller than the range of secondary electrons. However it is evident the difficulty to find a correlation between linear field dimensions and the percentage depth ionization curves. In the clinical practice it is important to take into account this difficulty when employing small or irregular electron fields.

Field separation in radiation therapy with opposing fields.

Dose distribution at the junction of two pairs of opposing fields with 60Co radiation was investigated. In order to obtain a uniform dose distribution, the field separation at the depth of interest was found to be the most important parameter. Values of this parameter to be used in every specific situation are reported. A simple formula is derived, which should be of practical help to the radiotherapist. This formula enables one to compute the field separation at the skin level in order to obtain the best dose distribution in the junction area at the tumor depth.

[Intraoperative radiotherapy with electrons (IORT). Dosimetry problems, first experience]. / Terapia intraoperatoria con elettroni (IORT). Problemi dosimetrici, prime esperienze.

In this paper, preliminary results on the IORT dosimetry performed on the two radiotherapy centers, "Regina Elena National Cancer Institute" and "S. Cuore Catholic University", are presented. The absolute dosimetry has been performed with ion chambers (ENEA chamber and Markus flat chamber) using a water phantom. The relative measurements have been performed with solid state diodes and radiographic films, calibrated on absolute dosimetry system.

Food allergy and Helicobacter pylori infection.

BACKGROUND: Most antigens reach the immune system through mucosae. Gastrointestinal mucosa is a barrier for alimentary antigens. Inflammatory processes, such as Helicobacter pylori-associated gastritis, could alter the integrity of the gastric barrier, increase the mucosal permeability, and enhance crossing of food antigens which may stimulate allergic reactions. PURPOSE: The aim of this study was to establish whether patients with symptomatic food allergy and detectable immunoglobulin E (IgE) to alimentary antigens were infected by Helicobacter pylori more often than controls, and to determine the phenotype of the infecting Helicobacter pylori. PATIENTS AND METHODS: Thirty-eight consecutive patients with symptomatic food allergy and serum IgE to alimentary antigens, and 53 consecutive age-matched controls (subjects without food allergy and detectable levels of IgE anti-alimentary antigens) living in the same area and attending the same institution were investigated serologically to determine the prevalence of Helicobacter pylori infection, and an immune response to CagA, a marker of the most pathogenic strains. IgE to alimentary allergens were measured by a commercial kit. RESULTS: The prevalence of Helicobacter pylori infection in patients with food allergy and controls was similar (42.1% and 47.1%, respectively). Anti-CagA antibodies in Helicobacter pylori-infected persons were detected in 62.5% of patients with food allergy, and 28.0% of controls (p = 0.030, odds ratio = 4.29, RR = 2.23). The mean IgE level to the most common alimentary antigens was increased in CagA-positive, with respect to the CagA-negative, patients. CONCLUSIONS: The enhanced mucosal and inflammatory lesions commonly found in individuals infected by CagA-positive Helicobacter pylori strains could increase the epithelial permeability and render non-selective the passage of allergens which, in atopic persons, could directly stimulate an IgE response. Infection by CagA-positive Helicobacter pylori may increase the risk of food allergy.

Device-specific risk of needlestick injury in Italian health care workers.

OBJECTIVES: To identify the types of medical devices causing needlestick injuries among Italian health care workers, to document the device-specific injury rates and time trends for different hollow-bore needles, and to compare injury rates from these devices with those reported in the United States. DESIGN: Longitudinal survey. SETTINGS: Twelve Italian acute care public hospitals. METHODS: Data were obtained from a multihospital surveillance database on the number of total injuries reported in each device category. Hospitals provided the corresponding number of devices used annually for each needle type. MAIN OUTCOME MEASURE: Number of needlestick injuries by type of hollow-bore needle per 100,000 devices used per year. RESULTS: A total of 2524 injuries from hollow-bore needles were reported. Disposable syringes/hypodermic needles accounted for 59.3% of injuries, followed by winged steel needles (33.1%), intravenous catheter stylets (5.4%), and vacuum-tube phlebotomy needles (2.2%). Intravenous catheter stylets had the highest needlestick injury rate (15.7/100,000 devices used), and disposable syringes had the lowest needlestick injury rate (3.8/100,000). In contrast to the other devices, the injury rate from winged steel needles increased from 6.2 per 100,000 in 1990 to 13.9 per 100,000 in 1992. CONCLUSIONS: The device-specific needlestick injury rates in Italy are similar to those reported in the United States, suggesting similar exposure experience in two countries. However, in contrast to the United States, needleless intravenous access is standard practice in Italy and thus eliminates one potential risk to Italian health workers. Implementation of safer equipment, such as shielded or retracting needles, and continuing training programs are needed to further reduce the hazards that health care workers face.