Nadia Falzone

In vitro effect of pulsed 900 MHz GSM radiation on mitochondrial membrane potential and motility of human spermatozoa

Ejaculated, density purified, human spermatozoa were exposed to pulsed 900 MHz GSM mobile phone radiation at two specific absorption rate levels (SAR 2.0 and 5.7 W/kg) and compared with controls over time. Change in sperm mitochondrial membrane potential was analysed using flow cytometry. Sperm motility was determined by computer assisted sperm analysis (CASA). There was no effect of pulsed 900 MHz GSM radiation on mitochondrial membrane potential. This was also the case for all kinematic parameters assessed at a SAR of 2.0 W/kg. However, over time, the two kinematic parameters straight line velocity (VSL) and beat-cross frequency (BCF) were significantly impaired (P < 0.05) after the exposure at SAR 5.7 W/kg and no exposure by time interaction was present. This result should not be ascribed to thermal effects, due to the cooling methods employed in the RF chamber and temperature control within the incubator.

Mobile Phone Radiation Does Not Induce Pro-apoptosis Effects in Human Spermatozoa

Abstract Recent reports suggest that mobile phone radiation may diminish male fertility. However, the effects of this radiation on human spermatozoa are largely unknown. The present study examined effects of the radiation on induction of apoptosis-related properties in human spermatozoa. Ejaculated, density-purified, highly motile human spermatozoa were exposed to mobile phone radiation at specific absorption rates (SARs) of 2.0 and 5.7 W/kg. At various times after exposure, flow cytometry was used to examine caspase 3 activity, externalization of phosphatidylserine (PS), induction of DNA strand breaks, and generation of reactive oxygen species. Mobile phone radiation had no statistically significant effect on any of the parameters studied. This suggests that the impairment of fertility reported in some studies was not caused by the induction of apoptosis in spermatozoa.

EGF-coated gold nanoparticles provide an efficient nano-scale delivery system for the molecular radiotherapy of EGFR-positive cancer

Abstract Purpose Radiolabeled antibodies and peptides hold promise for molecular radiotherapy but are often limited by a low payload resulting in inadequate delivery of radioactivity to tumour tissue and, therefore, modest therapeutic effect. We developed a facile synthetic method of radiolabeling indium-111 (111In) to epidermal growth factor (EGF)-gold nanoparticles (111In-EGF-Au NP) with a high payload. Materials and methods EGF-Au NP were prepared via an interaction between gold and the disulphide bonds of EGF and radiolabeled using 111InCl3. Targeting efficiency was investigated by quantitating internalized radioactivity and by confocal imaging following exposure of MDA-MB-468 (1.3 × 106 EGFR/cell) and MCF-7 (104 EGFR/cell) cells to Cy3-EGF-Au NP. Cytotoxicity was evaluated in clonogenic assays. Results The proportion of total administered radioactivity that was internalized by MDA-MB-468 and MCF-7 cells was 15% and 1.3%, respectively (mixing ratio of EGF:Au of 160). This differential uptake in the two cell lines was confirmed using confocal microscopy. 111In-EGF-Au NP were significantly more radiotoxic to MDA-MB-468 than MCF-7 cells with a surviving fraction of 17.1 ± 4.4% versus 89.8 ± 1.4% (p < 0.001) after exposure for 4 h. Conclusions An 111In-labeled EGF-Au nanosystem was developed. It enabled targeted delivery of a high 111In payload specifically to EGFR-positive cancer cells leading to radiotoxicity that can be exploited for molecularly targeted radiotherapy.

Amplification of DNA damage by a γH2AX-targeted radiopharmaceutical.

UNLABELLED (111)In-DTPA-anti-γH2AX-Tat, which combines an anti-γH2AX antibody with a cell-penetrating peptide, Tat, and the Auger electron-emitting radioisotope, (111)In, targets the DNA damage signalling protein, γH2AX, and has potential as a probe for imaging DNA damage in vivo. The goal of this study was to investigate whether (111)In-DTPA-anti-γH2AX-Tat labelled to high specific activity (6MBq/μg) can amplify treatment-related DNA damage for therapeutic gain. METHODS MDA-MB-468 and MDA-MB-231/H2N (231-H2N) breast cancer cells were incubated with (111)In-DTPA-anti-γH2AX-Tat (3MBq, 6MBq/μg) or a control radioimmunoconjugate, (111)In-DTPA-mIgG-Tat, and exposed to IR or bleomycin. DNA damage was studied by counting γH2AX foci and by neutral comet assay. Cytotoxicity was evaluated using clonogenic assays. (111)In-DTPA-anti-γH2AX-Tat was administered intravenously to 231-H2N-xenograft-bearing Balb/c nu/nu mice in tumor growth inhibition studies. RESULTS The number of γH2AX foci was greater after exposure of cells to IR (10Gy) plus (111)In-DTPA-anti-γH2AX-Tat compared to IR alone (20.6±2.5 versus 10.4±2.3 foci/cell; P<.001).(111)In-DTPA-anti-γH2AX-Tat resulted in a reduced surviving fraction in cells co-treated with IR (4Gy) versus IR alone (5.2%±0.9% versus 47.8%±2.8%; P<.001). Similarly, bleomycin (25-200μg/mL) plus (111)In-DTPA-anti-γH2AX-Tat resulted in a lower SF compared to bleomycin alone. The combination of a single exposure to IR (10Gy) plus (111)In-DTPA-anti-γH2AX-Tat significantly decreased the growth rate of 231-H2N xenografts in vivo compared to either (111)In-DTPA-anti-γH2AX-Tat or IR alone (-0.002±0.004 versus 0.036±0.011 and 0.031±0.014mm(3)/day, respectively, P<.001). CONCLUSION (111)In-DTPA-anti-γH2AX-Tat amplifies anticancer treatment-related DNA damage in vitro and has a potent anti-tumor effect when combined with IR in vivo.

Monte Carlo Evaluation of Auger Electron–Emitting Theranostic Radionuclides

Several radionuclides used in medical imaging emit Auger electrons, which, depending on the targeting strategy, either may be exploited for therapeutic purposes or may contribute to an unintentional mean absorbed dose burden. In this study, the virtues of 12 Auger electron–emitting radionuclides were evaluated in terms of cellular S values in concentric and eccentric cell–nucleus arrangements and by comparing their dose-point kernels. Methods: The Monte Carlo code PENELOPE was used to transport the full particulate spectrum of 67Ga, 80mBr, 89Zr, 90Nb, 99mTc, 111In, 117mSn, 119Sb, 123I, 125I, 195mPt, and 201Tl by means of event-by-event simulations. Cellular S values were calculated for varying cell and nucleus radii, and the effects of cell eccentricity on S values were evaluated. Dose-point kernels were determined up to 30 μm. Energy deposition at DNA scales was also compared with an α emitter, 223Ra. Results: PENELOPE-determined S values were generally within 10% of MIRD values when the source and target regions strongly overlapped, that is, S(nucleus←nucleus) configurations, but greater differences were noted for S(nucleus←cytoplasm) and S(nucleus←cell surface) configurations. Cell eccentricity had the greatest effect when the nucleus was small, compared with the cell size, and when the radiation sources were on the cell surface. Dose-point kernels taken together with the energy spectra of the radionuclides can account for some of the differences in energy deposition patterns between the radionuclides. The energy deposition of most Auger electron emitters at DNA scales of 2 nm or less exceeded that of a monoenergetic 5.77-MeV α particle, but not for 223Ra. Conclusion: A single-cell dosimetric approach is required to evaluate the efficacy of individual radionuclides for theranostic purposes, taking cell geometry into account, with internalizing and noninternalizing targeting strategies.

Carboxyhaemoglobin levels in water-pipe and cigarette smokers

UNLABELLED Water-pipe smoking is growing in popularity, especially among young people, because of the social nature of the smoking session and the assumption that the effects are less harmful than those of cigarette smoking. It has however been shown that a single water-pipe smoking session produces a 24-hour urinary cotinine level equivalent to smoking 10 cigarettes per day. AIM We aimed to measure carboxyhaemoglogin (COHb) blood levels before and after water-pipe and cigarette smoking sessions. METHOD Self-confessed smokers older than 18 years (N=30) volunteered to smoke a water-pipe or a cigarette and have their blood COHb levels measured under controlled conditions. RESULTS Mean baseline COHb levels were 2.9% for the 15 cigarette smokers and 1.0% for the 15 water-pipe smokers. Levels increased by a mean of 481.7% in water-pipe smokers as opposed to 39.9% in cigarette smokers. CONCLUSION The study demonstrated that water-pipe smokers had significantly higher increases in blood COHb levels than cigarette smokers during a single smoking session.

Comparison between propidium iodide and 7-amino-actinomycin-D for viability assessment during flow cytometric analyses of the human sperm acrosome

Evaluation of the acrosome reaction can shed light on the fertilising competence of spermatozoa. To eliminate false‐positive results when evaluating the acrosome status of human sperm cells, two viability probes propidium iodide (PI) and 7‐amino‐actinomycin D (7‐AAD) were compared for their ability to stain nonviable cells post‐fixation and permeabilisation. Both the mean fluorescence and % dead cells differed significantly with time (P < 0.0001). Unlike PI, 7‐AAD did not leach from cells and fluorescence remained stable for up to 4 h. Furthermore, 7‐AAD proved to be a proficient marker to exclude dead sperm cells during flow cytometric evaluation of ionophore‐induced acrosome reaction.

Targeted radionuclide therapy in combined-modality regimens

Targeted radionuclide therapy (TRT) is a branch of cancer medicine concerned with the use of radioisotopes, radiolabelled molecules, nanoparticles, or microparticles that either naturally accumulate in or are designed to target tumours. TRT combines the specificity of molecular and sometimes physical targeting with the potent cytotoxicity of ionising radiation. Targeting vectors for TRT include antibodies, antibody fragments, proteins, peptides, and small molecules. The diversity of available carrier molecules, together with the large panel of suitable radioisotopes with unique physicochemical properties, allows vector-radionuclide pairings to be matched to the molecular, pathological, and physical characteristics of a tumour. Some pairings are designed for dual therapeutic and diagnostic applications. Use of TRT is increasing with the adoption into practice of radium-223 dichloride for the treatment of bone metastases and with the ongoing clinical development of, among others, 177Lu-dodecanetetraacetic acid tyrosine-3-octreotate (DOTATATE) for the treatment of neuroendocrine tumours and 90Y-microspheres for the treatment of hepatic tumours. The increasing use of TRT raises the question of how best to integrate TRT into multimodality protocols. Achievements in this area and the future prospects of TRT are evaluated in this Review.

Individualized 131I-mIBG therapy in the management of refractory and relapsed neuroblastoma.

ObjectiveIodine-131-labelled meta-iodobenzylguanidine (131I-mIBG) therapy is an established treatment modality for relapsed/refractory neuroblastoma, most frequently administered according to fixed or weight-based criteria. We evaluate response and toxicity following a dosimetry-based, individualized approach. Materials and methodsA review of 44 treatments in 25 patients treated with 131I-mIBG therapy was performed. Patients received 131I-mIBG therapy following relapse (n=9), in refractory disease (n=12), or with surgically unresectable disease despite conventional treatment (n=4). Treatment schedule (including mIBG dose and number of administrations) was individualized according to the clinical status of the patient and dosimetry data from either a tracer study or previous administrations. Three-dimensional tumour dosimetry was also performed for eight patients. ResultsThe mean administered activity was 11089±7222 MBq and the mean whole-body dose for a single administration was 1.79±0.57 Gy. Tumour-absorbed doses varied considerably (3.70±3.37 mGy/MBq). CTCAE grade 3/4 neutropenia was documented following 82% treatments and grade 3/4 thrombocytopenia following 71% treatments. Further acute toxicity was found in 49% of patients. All acute toxicities resolved with appropriate therapy. The overall response rate was 58% (complete or partial response), with a further 29% of patients having stable disease. ConclusionA highly personalized approach combining patient-specific dosimetry and clinical judgement enables delivery of high activities that can be tolerated by patients, particularly with stem cell support. We report excellent response rates and acceptable toxicity following individualized 131I-mIBG therapy.

Chemically amplified photoresist for high resolution autoradiography in targeted radiotherapy.

Evaluation of the intracellular distribution of radionuclides used for targeted radiotherapy (tRT) is essential for accurate dosimetry. Therefore, a direct and quantitative method for subcellular micro-autoradiography using radiation sensitive polymers (PMMA, UV1116 and AZ40XT) was developed. The electron exposure dose in radio-labelled cells due to Auger and internal conversion (IC) electron emissions of indium (¹¹¹In), a radionuclide currently used for tRT, was calculated using Monte Carlo (MC) simulation. Electron beam lithography using pre-defined exposure doses was used to calibrate the resist response. The topography of the exposed and developed resists was analysed with atomic force microscopy (AFM) and the resulting pattern depth was related to a specific exposure dose. UV1116 exhibited the best contrast as compared to AZ40XT and PMMA, while AZ40XT exhibited the highest sensitivity at low doses (<10 μC/cm²). AFM analysis of the exposure pattern from radio-labelled cells and nuclei in UV1116 revealed a non-uniform distribution of ¹¹¹In-EGF in the cell and nucleus, consistent with less well-resolved data from confocal microscopy and micro-autoradiography.