Experimental validation of an innovative approach in biokinetics study for personalised dosimetry of molecular radiation therapy treatments

One of today's main challenges in molecular radiation therapy is to assess an individual dosimetry that allows treatment to be tailored to the specific patient, in accordance with the current paradigm of 'personalized medicine'. The evaluation of the absorbed doses for tumor and organs at risk in molecular radiotherapy is typically based on MIRD schema acquiring few experimental points for the assessement of biokinetic parameters. WIDMApp, the wearable individual dose monitoring apparatus, is an innovative approach for internal dosimetry based on a wearable radiation detecting system for individual biokinetics sampling, a Monte Carlo simulation for particle interaction, and an unfolding algorithm for data analysis and integrated activity determination at organ level. A prototype of a WIDMApp detector element was used to record the photon emissions in a body phantom containing 3 spheres with liquid sources (18F,64Cu and99mTc) to simulate organs having different washout. Modelling the phantom geometry on the basis of a CT scan imaging, the Monte Carlo simulation computed the contribution of each emitting sphere to the signal detected in 3 positions on the phantoms surface. Combining the simulated results with the data acquired for 120 h, the unfolding algorithm deconvolved the detected signal and assessed the decay half-life (T1/2) and initial activity values (A(0)) that best reproduces the observed exponential decays. A 3%-18% level of agreement is found between the actualA(0) andT1/2values and those obtained by means of the minimization procedure based on the Monte Carlo simulation. That resulted in an estimation of the cumulated activity <15%. Moreover, WIDMApp data redundancy has been used to mitigate some experimental occurrences that happened during data taking. A first experimental test of the WIDMApp approach to internal radiation dosimetry is presented. Studies with patients are foreseen to validate the technique in a real environment.

The importance of personal attitude toward Health issues: the Covid 19 Vaccination attitude

 

The project realize an idea from students of Scientific High school involved in a multidisciplinary path focused on “ONE HEALTH” approach and “ENVIRONMENTAL EDUCATION” After skill buildings webinars the students decided to build a survey in order to

Raise awareness about how any individual behavior Underline the importance of information, even scientific, in order to take appropriate choices. Build confidence in the effectiveness of the vaccination interventions against COVID 19

 

The project has been done by the students on the basis of multimedia digital tools, exploiting some IT tools like Google forms, PPTs, Spreadsheet, Excel. Students carried out an online survey addressed to a sample of the adult population among students' friends. Observational questionnaire asked the participants their sharing about some issues or the ticking of one or more options from a list of default answers. The survey involved a sample of people between 500 and 1000 units from April 15th to May 30th 2021.After the collection, all the data have been processed through tables and graphs according to the following macro-themes:

Boundaries against vaccines Use of personal protective equipment The most feared pandemic risks and their environmental implications

The outcome of the survey mainly highlights the population ‘attitude to get vaccine together with the awareness of the necessity of herd immunity achievement, to overcome this pandemic. Students stand point is that personal attitude toward prevention and personal behavior may have impact either on health or into environmental goals.

Prognostic and Predictive biomarkers in a Mediterranean cohort (Review from Atena Project)

Background

Atena project involved 5,062 women aged 30 to 69 years living in the area of Naples. The purpose of this study is to investigate the causes of those chronic diseases that have a major impact on the female population. As a part of the design (scheduled in 2002-2004). After 10 years, in 228 women, some biochemical measurements were performed.

Methods

This systematic review and meta-analysis biomarkers were evaluated in studies nested into the Atena cohort. Studies were searched using MEDLINE/PubMed. The search was performed by entering individually or in combination: Atena, Mediterranean woman, biomarkers. The preferred reporting of systematic reviews and meta-analysis (PRISMA) guidelines were used for the review. Studies selected for this review are conducted in the Atena project Cohort and reported the study of biomarkers. Disagreements on data extractions between the two investigators were solved by consensus. The extracted data were entered and analyzed using REVMAN software. The original articles were described using forest plot and table. Heterogeneity was computed by Cochran’s Q test.

Results

The search strategy retrieved 13 potential articles, 11 were screened as full text articles and 6 were included in the pooled estimates. Among the articles included, biomarkers chosen as predictors were Lipids, Hcrp, as prognostic where predictive of IMT; and cycle length and LPa as predictive of an augmented LDL cholesterol mean. According to the comparability of data presented, for the first comparison we selected 3 of the 5 studies that assed IMT, for the second we selected 2 of the three studies that analyzed for LDL mean. Results were shown into forrest plots. The pooled estimates verified the potential of biomarkers as predictor of IMT, the significance seemed lower for prediction of LDL cholesterol.

Conclusions

Both results, consistent with the multifactor profile of the CV risk, identify the impact of secondary prevention according to biochemical profiles.

Key messages

Biomarkers studied in nested cohort stufies have predictive potential. pooled estimates may identify the impact of secondary prevention according to biochemical profiles.

Advances in targeted alpha therapy for prostate cancer

Amongst therapeutic radiopharmaceuticals, targeted alpha therapy (TαT) can deliver potent and local radiation selectively to cancer cells as well as the tumor microenvironment and thereby control cancer while minimizing toxicity. In this review, we discuss the history, progress, and future potential of TαT in the treatment of prostate cancer, including dosimetry-individualized treatment planning, combinations with small-molecule therapies, and conjugation to molecules directed against antigens expressed by prostate cancer cells, such as prostate-specific membrane antigen (PSMA) or components of the tumor microenvironment. A clinical proof of concept that TαT is efficacious in treating bone-metastatic castration-resistant prostate cancer has been demonstrated by radium-223 via improved overall survival and long-term safety/tolerability in the phase III ALSYMPCA trial. Dosimetry calculation and pharmacokinetic measurements of TαT provide the potential for optimization and individualized treatment planning for a precision medicine-based cancer management paradigm. The ability to combine TαTs with other agents, including chemotherapy, androgen receptor-targeting agents, DNA repair inhibitors, and immuno-oncology agents, is under investigation. Currently, TαTs that specifically target prostate cancer cells expressing PSMA represents a promising therapeutic approach. Both PSMA-targeted actinium-225 and thorium-227 conjugates are under investigation. The described clinical benefit, safety and tolerability of radium-223 and the recent progress in TαT trial development suggest that TαT occupies an important new role in prostate cancer treatment. Ongoing studies with newer dosimetry methods, PSMA targeting, and novel approaches to combination therapies should expand the utility of TαT in prostate cancer treatment.

[Epidemiology of CKD in Italy and prevention strategies]

Although chronic kidney disease (CKD) is a major health problem worldwide; it is not adequately considered in the strategies for the prevention of non-communicable diseases. To plan properly preventive strategies in our country, we need to know what is the prevalence of CKD, the risk factors, the level of awareness for the diagnosis, the referral to specialists nephrologists and the prognosis of patients followed in primary care. The prevalence of CKD, adjusted for age and gender, is 6.3% and the major independent risk factors are represented by old age, arterial hypertension, obesity, diabetes, cardiovascular disease and smoking . The awareness of the diagnosis in our country in 2003 is underestimated and nephrology referral for individuals with glomerular filtration (GF) under 60 ml / min was only 10%. The prognosis of patients, followed exclusively in primary care, worsens progressively for values of GF under 45 ml / min, both as need for substitutive treatment and mortality, compared with patients of stage I and II. To improve the management of CKD, it would be useful to set up an electronic database on our national territory by a network among laboratories, primary care, and nephrologists. An example of this organization is Great Britain that evidences encouraging results in the treatment and prevention of this debilitating disease.

Use of the FLUKA Monte Carlo code for 3D patient-specific dosimetry on PET-CT and SPECT-CT images

Patient-specific absorbed dose calculation for nuclear medicine therapy is a topic of increasing interest. 3D dosimetry at the voxel level is one of the major improvements for the development of more accurate calculation techniques, as compared to the standard dosimetry at the organ level. This study aims to use the FLUKA Monte Carlo code to perform patient-specific 3D dosimetry through direct Monte Carlo simulation on PET-CT and SPECT-CT images. To this aim, dedicated routines were developed in the FLUKA environment. Two sets of simulations were performed on model and phantom images. Firstly, the correct handling of PET and SPECT images was tested under the assumption of homogeneous water medium by comparing FLUKA results with those obtained with the voxel kernel convolution method and with other Monte Carlo-based tools developed to the same purpose (the EGS-based 3D-RD software and the MCNP5-based MCID). Afterwards, the correct integration of the PET/SPECT and CT information was tested, performing direct simulations on PET/CT images for both homogeneous (water) and non-homogeneous (water with air, lung and bone inserts) phantoms. Comparison was performed with the other Monte Carlo tools performing direct simulation as well. The absorbed dose maps were compared at the voxel level. In the case of homogeneous water, by simulating 10(8) primary particles a 2% average difference with respect to the kernel convolution method was achieved; such difference was lower than the statistical uncertainty affecting the FLUKA results. The agreement with the other tools was within 3–4%, partially ascribable to the differences among the simulation algorithms. Including the CT-based density map, the average difference was always within 4% irrespective of the medium (water, air, bone), except for a maximum 6% value when comparing FLUKA and 3D-RD in air. The results confirmed that the routines were properly developed, opening the way for the use of FLUKA for patient-specific, image-based dosimetry in nuclear medicine.

An innovative iterative thresholding algorithm for tumour segmentation and volumetric quantification on SPECT images: Monte Carlo-based methodology and validation

PURPOSE

Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging play an important role in the segmentation of functioning parts of organs or tumours, but an accurate and reproducible delineation is still a challenging task. In this work, an innovative iterative thresholding method for tumour segmentation has been proposed and implemented for a SPECT system. This method, which is based on experimental threshold-volume calibrations, implements also the recovery coefficients (RC) of the imaging system, so it has been called recovering iterative thresholding method (RIThM). The possibility to employ Monte Carlo (MC) simulations for system calibration was also investigated.

METHODS

The RIThM is an iterative algorithm coded using MATLAB: after an initial rough estimate of the volume of interest, the following calculations are repeated: (i) the corresponding source-to-background ratio (SBR) is measured and corrected by means of the RC curve; (ii) the threshold corresponding to the amended SBR value and the volume estimate is then found using threshold-volume data; (iii) new volume estimate is obtained by image thresholding. The process goes on until convergence. The RIThM was implemented for an Infinia Hawkeye 4 (GE Healthcare) SPECT/CT system, using a Jaszczak phantom and several test objects. Two MC codes were tested to simulate the calibration images: SIMIND and SimSet. For validation, test images consisting of hot spheres and some anatomical structures of the Zubal head phantom were simulated with SIMIND code. Additional test objects (flasks and vials) were also imaged experimentally. Finally, the RIThM was applied to evaluate three cases of brain metastases and two cases of high grade gliomas.

RESULTS

Comparing experimental thresholds and those obtained by MC simulations, a maximum difference of about 4% was found, within the errors (+/- 2% and +/- 5%, for volumes > or = 5 ml or < 5 ml, respectively). Also for the RC data, the comparison showed differences (up to 8%) within the assigned error (+/- 6%). ANOVA test demonstrated that the calibration results (in terms of thresholds or RCs at various volumes) obtained by MC simulations were indistinguishable from those obtained experimentally. The accuracy in volume determination for the simulated hot spheres was between -9% and 15% in the range 4-270 ml, whereas for volumes less than 4 ml (in the range 1-3 ml) the difference increased abruptly reaching values greater than 100%. For the Zubal head phantom, errors ranged between 9% and 18%. For the experimental test images, the accuracy level was within +/- 10%, for volumes in the range 20-110 ml. The preliminary test of application on patients evidenced the suitability of the method in a clinical setting.

CONCLUSIONS

The MC-guided delineation of tumor volume may reduce the acquisition time required for the experimental calibration. Analysis of images of several simulated and experimental test objects, Zubal head phantom and clinical cases demonstrated the robustness, suitability, accuracy, and speed of the proposed method. Nevertheless, studies concerning tumors of irregular shape and/or nonuniform distribution of the background activity are still in progress.

Targeting T and B lymphocytes with radiolabelled antibodies for diagnostic and therapeutic applications

Acute and chronic forms of inflammation may occur years before the onset of specific symptoms, on which the clinical diagnosis can be settled, and may last for years after the clinical diagnosis and the onset of treatment. Therefore, to develop a sensitive and specific diagnostic tool several novel molecules/ receptors identified and new antibodies have been radiolabelled with different radionuclides, as per their need for diagnosis or therapy. Cluster of differentiation (CD) molecules are markers on the cell surface used to identify the cell type, stage of differentiation and activity of a cell. These CD markers are recognized by specific monoclonal antibodies (mAbs). These radiolabelled mAbs bind to their targets with high affinity and specificity and consequently have an excellent diagnostic and/ or therapeutic potential. In the last two decades, the radiolabelled mAbs have demonstrated its significant impact on diagnosis and radioimmunotherapy. In this review article, we will discuss different possible targets for T and B cells and their radiolabelled mAbs for molecular imaging and radioimmunotherapy.

Feline herpesvirus-1 down-regulates MHC class I expression in an homologous cell system

Cytotoxic T lymphocytes (CTLs) are an essential component of the immune defense against many virus infections. CTLs recognize viral peptides in the context of the major histocompatibility complex (MHC) class I molecules on the surface of infected cells. Many viruses have evolved mechanisms to interfere with MHC class I expression as a means of evading the host immune response. In the present research we have studied the effect of in vitro Feline Herpesvirus 1 (FeHV-1) infection on MHC class I expression. The results of this study demonstrate that FeHV-1 down regulates surface expression of MHC class I molecules on infected cells, presumably to evade cytotoxic T-cell recognition and, perhaps, attenuate induction of immunity. Sensitivity to UV irradiation and insensitivity to a viral DNA synthesis inhibitor, like phosphonacetic acid, revealed that immediate early or early viral gene(s) are responsible. Use of the protein translation inhibitor cycloheximide confirmed that an early gene is primarily responsible.

2,3,7,8-Tetrachlorodibenzo-p-dioxin increases Bovine Herpesvirus type-1 (BHV-1) replication in Madin-Darby Bovine Kidney (MDBK) cells in vitro

Dioxin-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a common environmental toxin of current interest. In the last years, higher levels of TCDD than those permitted in UE [European Commission. 2002. European Commission Recommendation 2002/201/CE. Official Gazette, L 67/69] were detected in milk samples from cow, water buffalo, goat, and sheep raised on some areas of Campania Region (South Italy). Dioxin often causes immunosuppression and might render the animal liable to viral infections. In addition, viral infections are able to alter the pattern of dioxin distribution in different organs of the exposed animals. Bovine Herpesvirus type-1 (BHV-1) is a widespread pathogen, which causes infectious rhinotracheitis and infectious pustular vulvovaginitis in cattle. Herein, we have studied the effects of TCDD and BHV-1 infection, in Madin-Darby Bovine Kidney (MDBK) cells, alone as well as in association, so as cellular proliferation, apoptosis, and virus replication. We have observed an increase in cell viability of confluent monolayers at low TCDD concentrations. TCDD treated cells demonstrated increased viability compared to controls as evaluated by MTT test. TCDD exposure increased cell proliferation but induced no changes on apoptosis. Cells exposed to TCDD along with BHV-1 showed a dose-dependent increase in cytopathy, represented by ample syncytia formation with the elimination of the cellular sheets and increased viral titer. These results suggest that TCDD increases viral replication in MDBK cells while BHV-1 further decreases viability of TCDD exposed cells. Since very low concentrations (0.01 pg/ml) are sufficient to augment BHV-1 titer, TCDD may contribute to reactivate BHV-1 from latency, leading to recurrent disease and increase virus transmission.

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.

Ion diffusion modelling of Fricke-agarose dosemeter gels

In Fricke-agarose gels, an accurate determination of the spatial dose distribution is hindered by the diffusion of ferric ions. In this work, a model was developed to describe the diffusion process within gel samples of finite length and, thus, permit the reconstruction of the initial spatial distribution of the ferric ions. The temporal evolution of the ion concentration as a function of the initial concentration is derived by solving Fick's second law of diffusion in two dimensions with boundary reflections. The model was applied to magnetic resonance imaging data acquired at high spatial resolution (0.3 mm) and was found to describe accurately the observed diffusion effects.

Optical imaging of dose distributions in Fricke gels

Ferrous-sulphate infused gels, or 'Fricke gels', encounter great interest in the field of radiation dosimetry, due to their potential for 3D radiation dose mapping. Typically, magnetic resonance (MR) relaxation rates are determined in these systems in order to derive the absorbed dose. However, when large concentration gradients are present, diffusion effects before and during the MR imaging may not be negligible. In these cases, optical techniques may represent a viable alternative. This paper describes research aimed at measuring 3D dose distributions in a Fricke-xylenol orange gel by measuring optical density with a CCD camera. This method is inexpensive and fast. A series of early experiments is described, in which optical density profiles were measured with a commercial microdensitometer for film dosimetry. The light box of the device was modified to work at 567 nm, close to the maximum absorbance of the ferric ion-xylenol orange complex. Under these conditions, the gel shows linearity with dose and high sensitivity.

Effect on prolactin secretion of Echinacea purpurea, hypericum perforatum and Eleutherococcus senticosus

It has been recently reported that prolactin (PRL) plays an important role in immune system regulation. In this study we investigated the activity of three natural drugs with immunomodulatory activity: Echinacea purpurea (EP), Hypericum perforatum (HP) and Eleutherococcus senticosus (ES) on PRL production. Male rats were orally treated with two different doses (30 and 100 mg/kg) of extract of these drugs for 3 or 15 days. A 3-day treatment was not able to modify PRL serum levels, whereas a 15-day treatment with EP and HP at the higher dose significantly inhibits PRL production. A treatment with ES was always ineffective. A possible mechanism for this effect could be that both HP and EP extracts display a direct dopaminergic activity, although an involvement of the GABA-ergic system cannot be excluded.

The involvement of oxidative stress in bovine herpesvirus type 4-mediated apoptosis

Bovine herpesvirus type 4 (BHV-4) belongs to the gamma-2-herpesviruses of the Gammaherpesvirinae subfamily. BHV-4 has a worldwide distribution and has been isolated in a variety of clinical diseases as well as from healthy cattle. In this report we demonstrate that BHV-4 induces apoptosis in MDBK cells. In the early phases of apoptosis, cells show an increase in the intracellular level of reactive oxygen species, which is indicative of oxidative stress. This precedes DNA fragmentation, a hallmark typical of apoptosis. Cells were protected from apoptosis only by certain antioxidants (butylated hydroxyanisole and ebselen), whereas N-acetylcysteine turned out to be ineffective. Antioxidants that protected cells from apoptosis prevented oxidative stress but failed to block virus growth. These observations suggest that oxidative stress may be a crucial event in the sequence leading to apoptotic cell death but apoptosis is not required for the multiplication of BHV-4.

A correction method for diamond detector signal dependence with proton energy

Small dosimeters as solid state detectors can be useful for the dosimetric characterization and periodic quality control of radiotherapy proton beams. The calibration of solid state detectors for proton beams is not a solved problem especially for ophthalmologic proton beams, where these detectors present a LET-dependent signal. In this work a PTW diamond detector has been selected because of its good signal reproducibility (0.3%) and stable response with accumulated dose. A method that takes into account the LET dependence of the diamond detector signal, at 62 MeV proton beam, is here proposed. In particular an empirical correction factor, kDD(Eo) (Rres), has been determined as a function of the residual range quality index, to correct the diamond detector signal for a proton beam of incident effective energy E0= 62 MeV. A dedicated software allows us to use the diamond detector as an on-line reference dosimeter, where an ionization chamber may be difficult to use, or for periodic quality control procedures. The article also reports a comparison between the signal dependence on proton energy of silicon, diamond, and radiochromic film detectors.

Characteristics of silicon and diamond detectors in a 60 MeV proton beam

The calibration factor variation for a PTW natural diamond detector and a Scanditronix p-type stereotactic silicon diode (designed for use in photon beams) was studied in the 10-59 MeV range. Irradiations were performed in a water phantom with the 60 MeV ocular therapy beam at the CCO (UK). The diamond detector showed a sensitivity increase with energy, underestimating the dose by about 18% at the Bragg peak, by 7% at the centre and by 17% at the distal end of the SOBP region. The silicon diode did not show any significant sensitivity change with energy. However, a decrease in response of 24% was observed for an accumulated dose of 300 Gy.

An investigation of the operating characteristics of two PTW diamond detectors in photon and electron beams

The dosimetric properties of two PTW Riga diamond detectors type 60003 were studied in high-energy photon and electron therapy beam. Properties under study were current-voltage characteristic, polarization effect, time stability of response, dose response, dose-rate dependence, temperature stability, and beam quality dependence of the sensitivity factor. Differences were shown between the two detectors for most of the previous properties. Also, the observed behavior was, to some extent, different from what was reported in the PTW technical specifications. The necessity to characterize each diamond detector individually was addressed.

Dose reconstruction in irradiated Fricke-agarose gels by means of MRI and optical techniques: 2D modelling of diffusion of ferric ions

Fricke-agarose gels have elicited much interest in the field of radiation dosimetry, as tissue-equivalent dosemeters. magnetic resonance (MR) relaxation rates are measured for dose reconstruction. A major problem of Fricke-agarose gels is the diffusion of the ferric ions formed after irradiation. Knowledge of the diffusion coefficient of ferric ions may be necessary. Xylene orange, a dye that specifically chelates ferric ions, was added to the Fricke gel system to reduce ion diffusion and, as the binding gives a coloured complex, to allow optical detection of ferric ions. Diffusion of ferric ions in two dimensions and time evolution of ion concentration were evaluated. MR images were obtained at different times after irradiation. Ferric ion distribution, the corresponding images and the doses at different times after irradiation were reconstructed taking into account the calculated diffusion coefficients. Diffusion was then estimated by means of two different optical methods. The agreement obtained supports the reliability of the MRI method and of the model.

Elevated bioactive prolactin levels in systemic lupus erythematosus--association with disease activity

OBJECTIVE

To assess the possibility that prolactin (PRL) is involved in the pathogenesis of systemic lupus erythematosus (SLE).

METHODS

We determined serum PRL levels in 122 serum samples from 78 unselected patients with SLE (73 women, 5 men, age range 16-71 yrs). Disease activity was defined according to Lupus Activity Criteria Count (LACC) and scored by Systemic Lupus Disease Activity Index (SLEDAI). Serum PRL concentrations were determined by immunoradiometric assay (IRMA) and by biological assay (BA) that evaluates Nb2 lymphoma cell proliferation.

RESULTS

Hyperprolactinemia (> 20 ng/ml) was found in 21 patients (26.9%) by IRMA and in 31 (39.7%) by BA. A significant correlation between IRMA and BA PRL levels was found (rs 0.46, p < 0.001). According to LACC, SLE was active in 29 patients and inactive in 49. In those with active disease median PRL levels were higher both by IRMA (18.5 ng/ml, range 2.2-51.2 vs 10.6 ng/ml, range 3.9-29.6; p < 0.001) and BA (21.0 ng/ml, range 12.4-84 vs 14.9 ng/ml, range 4.2-46.1; p < 0.001). Hyperprolactinemia was associated with active disease in 13/21 patients (61.9%) by IRMA and in 18/31 (58.1%) by BA (p < 0.01). SLEDAI scores correlated with PRL levels both by IRMA (rs 0.5, p < 0.001) and BA (rs 0.41, p < 0.02). A followup analysis on serum samples from 44 patients seen again after 6-8 mo confirmed the above results. There was no difference in the rate of different clinical manifestations in hyperprolactinemic and normoprolactinemic subjects, apart from the increased prevalence of malar rash and central nervous system manifestations in the patients with hyperprolactinemia (p < 0.03 and p < 0.01, respectively).

CONCLUSION

Hyperprolactinemia was frequently detected in patients with SLE by IRMA and by BA and was associated with disease activity. Our findings suggest that PRL may play a role in the pathogenesis of SLE.

Thrombopoietin induces histidine decarboxylase gene expression in c-mpl transfected UT7 cells

The leukemic cell line UT7 is endowed with both megakaryocyte and basophil differentiation potential, as judged by its capacity to respond to PMA by displaying megakaryocytic and basophilic markers and to produce histamine by neosynthesis. Herein, we addressed the question whether the biological activities characteristic of basophil differentiation were still induced when c-mpl-transfected UT7 cells received a specific megakaryocytic differentiation signal delivered by thrombopoietin (TPO). Surprisingly, we found that histamine synthesis did effectively occur in response to the growth factor. This activity was not associated with megakaryopoiesis since it was not detected in megakaryocytes generated from CD34(+) cells cultured in the presence of TPO. Comparing different c-mpl-transfected cell lines, we found that the amount of histamine generated in response to TPO correlated with their responsiveness to PMA, but not with their level of c-mpl expression, thus revealing an intrinsic basophil differentiation potential. Both PMA- and TPO-induced histamine synthesis was reduced by PKC and MEKs inhibitors, indicating that the induction occurred through a common signalling pathway.

IL-18 enhances IL-4 production by ligand-activated NKT lymphocytes: a pro-Th2 effect of IL-18 exerted through NKT cells

NKT cells are a remarkably versatile population whose functional capacities are determined by cytokines present in their microenvironment. In this study, we provide evidence for a new immunoregulatory effect of the proinflammatory cytokine IL-18 on NKT cells. We found that IL-18, mainly known for its involvement in NK cell activation and in Th 1 immune responses, substantially enhanced IL-4 production as well as the percentage of IL-4(+) cells among NKT lymphocytes activated by their specific ligand alpha-galactosylceramide (alpha-GalCer). The effect of IL-18 on IL-4 production by activated NKT cells took place both in vivo and in vitro and was not affected by IL-12 which increased IFN-gamma secretion in the same conditions. We show that NKT cells are the main targets for IL-18-induced IL-4 production since it occurred neither in NKT-deficient mice nor after stimulation of Th2 lymphocytes. Finally, we provide evidence that the IL-4 promptly generated by NKT cells in response to IL-18 plus alpha-galactosylceramide in vivo can effectively contribute to the adaptive Th2 immune response by up-regulating the early activation marker CD69 on B cells. Our data support the notion that, in contrast to the exclusive IFN-gamma inducer IL-12, IL-18 acts in a more subtle manner as a costimulatory factor in both pro-Th1 and pro-Th2 responses depending on the nature of the stimulation and the target cells.

Inhibition of inducible nitric oxide synthase and cyclooxygenase-2 expression by flavonoids in macrophage J774A.1

The present study focuses on the effect of various naturally occurring flavonoids (apigenin, galangin, morin, naringenin, quercetin, and silymarin) on nitric oxide (NO) and prostaglandin E2 (PGE2) production induced by lipopolysaccharide (LPS) in the macrophage cell line J774A.1. Moreover, we evaluated flavonoid modulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) enzyme expression by western blot analysis. Apigenin and quercetin (0.5-50 microM) were the most potent inhibitors of NO production and this effect was concentration-dependent and significant at 5 and 50 microM. These data were consistent with the modulation of iNOS enzyme expression. A similar pattern was observed considering the inhibitory effect of flavonoids on LPS-induced PGE2 release and COX-2 expression. Quercetin, galangin, apigenin, and naringenin markedly decreased PGE2 release and COX-2 expression in a concentration-dependent manner. This study suggests that inhibition of iNOS and COX-2 expression by flavonoids may be one of the mechanisms responsible for their anti-inflammatory effects.

Dosimetric characterization of silicon and diamond detectors in low-energy proton beams

The dosimetric behaviour of a Scanditronix p-type silicon diode and a PTW natural diamond detector was studied in low-energy proton beams in the 8.3-21.5 MeV range. The properties investigated were linearity, reproducibility, dose rate dependence, energy and linear energy transfer (LET) dependence. The influence of detector thickness on the results of depth dose measurements was also demonstrated. A Markus parallel plate ionization chamber was used for reference dosimetry. Silicon diode and diamond detectors showed linearity at therapeutic dose level, reproducibility better than 1% (1sigma) and sensitivity variation with dose rate and proton energy.

Radiochromic film dosimetry of a low energy proton beam

In this work some dosimetric characteristics of MD-55-2 GafChromic films were studied in a low energy proton beam (21.5 MeV) directly in a water phantom. The nonlinearity of the optical density was quantified by a factor P(lin). A correction factor P(en), that accounts for optical density dependence on the energy, was empirically determined. The effects of detector thickness in depth dose measurements and of the film orientation with respect to beam direction were investigated. The results show that the MD-55-2 films provide dose measurements with the films positioned perpendicularly to the proton beam. A dosimetric formalizm is proposed to determine the dose to water at depth d, with films oriented perpendicularly to the beam axis. This formalism uses a calibration factor of the radiochromic film determined directly on the proton beam at a reference depth in water, and the P(lin) factor, that takes into account the nonlinearity of the calibration curve and the P(en) factor that, in turn takes into account the change of proton beam energy in water. The MD-55-2 films with their high spatial resolution and the quasiwater equivalent material are attractive, positioned perpendicularly along the beam axis, for the absolute dose determination of very small beam sizes and modulated proton beams.

Bayesian estimation of relaxation times T(1) in MR images of irradiated Fricke-agarose gels

The authors present a novel method for processing T(1)-weighted images acquired with Inversion-Recovery (IR) sequence. The method, developed within the Bayesian framework, takes into account a priori knowledge about the spatial regularity of the parameters to be estimated. Inference is drawn by means of Markov Chains Monte Carlo algorithms. The method has been applied to the processing of IR images from irradiated Fricke-agarose gels, proposed in the past as relative dosimeter to verify radiotherapeutic treatment planning systems. Comparison with results obtained from a standard approach shows that signal-to noise ratio (SNR) is strongly enhanced when the estimation of the longitudinal relaxation rate (R1) is performed with the newly proposed statistical approach. Furthermore, the method allows the use of more complex models of the signal. Finally, an appreciable reduction of total acquisition time can be obtained due to the possibility of using a reduced number of images. The method can also be applied to T(1) mapping of other systems.

Prolactin induction of nitric oxide synthase in rat C6 glioma cells

We have examined the neuroimmunoregulatory function of prolactin (PRL) on astrocytic inducible nitric oxide synthase (iNOS) expression in the C6 glioma cell line. After 24 h of PRL (5-100 nM) stimulation, a concentration-dependent increase of NO release, evaluated as nitrite, was observed in C6 culture medium. Moreover, both NO release and iNOS expression induced by interferon-gamma (250 U/ml) were enhanced by PRL (18-100 nM). PRL-induced NO release was inhibited by dexamethasone, an inhibitor of de novo iNOS synthesis. We used erbstatin (5 microg/ml), a potent inhibitor of protein tyrosine kinases, to test whether these proteins were required for signaling events evoked by PRL in these cells. This inhibitor was able to inhibit completely the PRL-induced NO production and iNOS expression. In conclusion, we provide evidence that NO production in glial cells can be regulated not only by cytokines but also by neuroimmunoregulatory hormones such as PRL, which is present in normal brain but may be elevated in several pathological states.

Modulation of histidine decarboxylase activity and cytokine synthesis in human leukemic cell lines: relationship with basophilic and/or megakaryocytic differentiation

In the present study, we show that UT7D1 cells, derived from the pluripotent cell line UT7, express high levels of histidine decarboxylase (HDC) mRNA spontaneously. These cells conserve the ability to differentiate into megakaryocytes upon stimulation with PMA, while greatly increasing their HDC activity. We provide evidence that enhanced HDC activity reflects the basophil rather than the megakaryocytic differentiation potential of UT7DI cells. Indeed, in addition to HDC mRNA, they express spontaneously several other mRNA coding for molecules present in basophils (FcepsilonRI, CCR3, IL-4Ralpha, IL-5Ralpha). Furthermore, the basophil antigen Bsp-1 is displayed on the surface of some UT7D1 cells in response to PMA concomitantly with increased histamine synthesis and mRNA expression of typical basophil-derived cytokines (IL-6, IL-4, and IL-13). Nevertheless, PMA cannot sustain the differentiation of this lineage, because mRNAs for basophil markers gradually diminish during long-term culture, whereas molecules associated with the megakaryocytic lineage remain prominent. In support of the notion that HDC activity is not related with megakaryopoiesis, we show that PMA-induced CD41 expression and PDGF transcription occurs in the K562 cells, though neither HDC mRNA nor any known basophil marker are expressed in these conditions. In contrast, all these markers are expressed in the basophilic leukemia cell line KU812F. Interestingly, the megakaryocytic cell line HEL produces also substantial amounts of histamine and expresses FcepsilonRI, thus revealing its basophil differentiation potential. HEL as well as KU812F need not be stimulated with PMA to react with Bsp-1 mAb, suggesting that they are more engaged into the basophil differentiation scheme than UT7D1. Other leukemic cell lines unrelated to the megakaryocyte or basophil lineage, like HL60 and U937 do neither synthesize histamine nor express basophil markers before or after PMA stimulation. To our knowledge, this is the first evidence for a factor-dependent cell line with megakaryocyte/basophil bipotentiality with which early stages of basophil commitment can be analyzed.

Prolactin modulation of nitric oxide and TNF-alpha production by peripheral neutrophils in rats

It has been demonstrated that prolactin (PRL) is a potent immunomodulator that exerts stimulatory effects on physiological responses of immune cells. In the present research we have investigated whether PRL may influence nitric oxide (NO) and/or tumor necrosis factor-alpha (TNF-alpha) production in neutrophils obtained from inflammatory exudate of carrageenin-induced experimental pleurisy in the rat. In this acute model of inflammation the role of endogenous NO was evaluated using an inhibitor of NO-synthase, NG-nitro-L-arginine methyl ester (L-NAME). A treatment of animals with L-NAME (10 mg/kg s.c.) induced a reduction of volume and cell number of pleural exudate and a decrease of nitrite production (measured by the Griees reaction) by polymorphonuclear cells after 24 h of incubation, while D-NAME, the inactive isomer, was without effect. Neutrophils from ovine prolactin (oPRL) treated rats (5 mg/kg for 5 times s.c.) or from rats with a hyperprolactinaemia induced by pituitary gland graft produced higher amounts of NO both after 24 and 48 h of incubation. On the contrary, a clear reduction in the production of NO was found in neutrophils from rats treated with bromocriptine (BRC) (2 mg/kg s.c.), a dopamine D2-receptor agonist. TNF-alpha production (measured by MTT/cytotoxic assay) by neutrophils was markedly increased in PRL-treated or pituitary-grafted rats in comparison to controls, whereas BRC treatment reduced TNF-alpha production.

Preparation and local anaesthetic activity of N-[2-(tert-amino)ethyl]- and N-(lupinyl)-benzotriazol-1/2-ylacetamides

Two sets of N-[2-(tert-amino)ethyl]- and N-[(quinolizidin-1 alpha-yl) methyl]-benzotriazol-2-ylacetamides, bearing substituents on position 5 or 5 and 6, were prepared and tested for local anaesthetic activity in comparison with lidocaine. Most of the prepared compounds exhibited a fairly good activity comparable or superior to that of lidocaine. The introduction of substituents on the benzene ring and the replacement of the usual tert-amino alkyl chains with the quinolizidin-1 alpha-ylmethyl (lupinyl) moiety were quite profitable for both the intensity and duration of activity. One selected compound was subjected to a large pharmacological screening and found endowed with a good level of the purported antiarrhythmic activity without any other disturbing activity.