Impact of breath hold on regional nodal irradiation and heart volume in field in left breast cancer adjuvant irradiation.

PURPOSE: Compared to the free-breathing technique, adjuvant left breast irradiation after breast-conserving surgery or mastectomy using the breath-hold method significantly reduces the heart mean dose, Left anterior descending artery, and ipsilateral lung doses. Movement with deep inspiration may also reduce heart volume in the field and regional node doses. MATERIALS AND METHODS: Pre-radiotherapy planning CT was performed in the free-breathing, and breath-hold techniques using RPM, demographic information, clinicopathological data, heart volume in the field, heart mean dose, LAD mean dose, and regional nodal doses were calculated in both free breathing and DIBH. Fifty patients with left breast cancer receiving left breast adjuvant radiation were enrolled. RESULTS: There was no significant difference in axillary LN coverage between the two techniques, except for SCL maximum dose, Axilla I node maximum dose, and Axilla II minimum dose in favor of the breath hold technique. The mean age was 47.54 years, 78% had GII IDC, 66% had positive LVSI results, and 74% of patients had T2. The breath hold strategy resulted in considerably decreased mean heart dose (p = 0.000), LAD dose (p = 0.000), ipsilateral lung mean dose (p = 0.012), and heart volume if the field (p = 0.013). The mean cardiac dosage and the dose of the LAD were significantly correlated (p = 0.000, R = 0.673). Heart volume in the field and heart mean dosage was not significantly correlated (p = 0.285, r = - 0.108). CONCLUSION: When compared to free breathing scans, DIBH procedures result in considerably reduced dosage to the OAR and no appreciable changes in dose exposure to regional lymph node stations in patients with left-sided breast cancer.

Predicted cardiac and second cancer risks for patients undergoing VMAT for mediastinal Hodgkin lymphoma.

BACKGROUND AND PURPOSE: To predict treatment-related cardiovascular disease (CVD) and second cancer 30-year absolute mortality risks (AMR30) for patients with mediastinal Hodgkin lymphoma in a large multicentre radiation oncology network in Ireland. MATERIAL AND METHODS: This study includes consecutive patients treated for mediastinal lymphoma using chemotherapy and involved site radiotherapy (RT) 2016-2019. Radiation doses to heart, left ventricle, cardiac valves, lungs, oesophagus, carotid arteries and female breasts were calculated. Individual CVD and second cancer AMR30 were predicted using Irish background population rates and dose-response relationships. RESULTS: Forty-four patients with Hodgkin lymphoma were identified, 23 females, median age 28 years. Ninety-eight percent received anthracycline, 80% received 4-6 cycles ABVD. Volumetric modulated arc therapy (VMAT) ± deep inspiration breath hold (DIBH) was delivered, median total prescribed dose 30 Gy. Average mean heart dose 9.8 Gy (range 0.2-23.8 Gy). Excess treatment-related mean AMR30 from CVD was 2.18% (0.79, 0.90, 0.01, 0.13 and 0.35% for coronary disease, heart failure, valvular disease, stroke and other cardiac diseases), 1.07% due to chemotherapy and a further 1.11% from RT. Excess mean AMR30 for second cancers following RT were: lung cancer 2.20%, breast cancer in females 0.34%, and oesophageal cancer 0.28%. CONCLUSION: For patients with mediastinal lymphoma excess mortality risks from CVD and second cancers remain clinically significant despite contemporary chemotherapy and photon-RT. Efforts to reduce the toxicity of combined modality treatment, for example, using DIBH, reduced margins and advanced RT, e.g. proton beam therapy, should be continued to further reduce potentially fatal treatment effects.

Radioprotective Effect of Nigella Sativa Oil on Heart Tissues of Rats Exposed to Irradition

Abstract Background Various studies are ongoing related to the radioprotective agents. Herbal preparations are currently becoming popular because of their beneficial effects with fewer side effects compared to the synthetic/semi-synthetic medicines, and Nigella sativa oil (NSO) is only one of them. Objective To investigate NSO for its antioxidant effects on the heart tissue of rats exposed to ionizing radiation (IR). Methods Thirty six male albino Wistar rats, divided into four groups, were designated to group I (IR plus NSO group) that received both 5 Gray of gamma IR to total cranium and NSO; group II (IR alone group) that received IR plus saline, group III (control group of NSO) that received saline and did not receive NSO or IR; group IV (control group) that received only sham IR. Alterations in Total antioxidant status (TAS) and Total oxidant status (TOS), Oxidative stres index (OSI), Sulhydryl group (SH), Lipid hydroperoxide (LOOH), Paraoxonase (PON) levels, Arylesterase (ARE) and Ceruloplasmin (CER) activities in homogenized heart tissue of rats were measured by biochemical methods. Results In heart tissue of the rats in the IR alone group (group II) LOOH, TOS and OSI levels were found to be higher, ARE activity and TAS level were found to be lower than all of the other groups (p < 0.01). These results also support that IR increases oxidative stress and NSO's protective effect. Conclusion NSO would reduce the oxidative damage in the irradiated heart tissue in the experimental rat model.

5-year results of accelerated partial breast irradiation (APBI) with SBRT (stereotactic body radiation therapy) and exactrac adaptive gating (Novalis®) for very early breast cancer patients: was it all worth it?

PURPOSE: To explore the feasibility of image-guided and respiratory-gated Stereotactic Body Radiation Therapy (SBRT) for Accelerated Partial Breast Irradiation (APBI) in patients with very early breast cancer. MATERIAL AND METHODS: Selected patients with early breast carcinoma after breast-conserving surgery were enrolled in this phase II trial. A fiducial marker was percutaneously placed close to surgical bed and five external fiducials were set on the skin. A CT scan for planning was acquired at free breathing. The treatment was planned and DVH were assessed according to international recommendations. Prescription dose was 30 Gy in five consecutive fractions of 6 Gy. A 6MV monoenergetic LINAC (linear accelerator) that combines stereoscopic X-ray imaging system and ExacTrac Adaptive Gating technique was used. PTV (planning target volume) intrafraction motion was controlled and PTV was irradiated in a selected gated area of the respiratory cycle. Shifts for a correct, gated set-up were calculated and automatically applied. RESULTS: Between April 2013 and October 2015, a total of 23 patients were included. The median tumor size was 12 mm. The mean PTV volume was 114 cc. The mean ipsilateral lung V9 Gy was 2.2% and for left-sided breast cancers, the volume of the heart receiving 1.5 Gy was 11.5%. Maximum skin dose was 30.8 Gy. Acute toxicity was grade1 in all the patients and 100% experienced excellent/good breast cosmesis outcomes. With a median follow-up of 66 months (range 8-99 months) local-relapse-free-survival reaches 100%. One patient developed a second breast cancer outside the treated quadrant after 25.1 months. CONCLUSION: APBI with SBRT and ExacTrac Adaptive Gating System was feasible. The acute and late toxicities were almost null and cosmesis was excellent. We also found that the margins of 5 mm applied from CTV to PTV were sufficient to compensate for geometric uncertainties.

Synchronous bilateral breast cancer treated with a 3-week hypofractionated radiotherapy schedule: clinical and dosimetric outcomes.

BACKGROUND AND PURPOSE: Synchronous bilateral breast cancer (SBBC) accounts for 1-3.5% of breast cancer patients. The aim of this study was to evaluate dosimetric issues, clinical outcomes, and acute toxicities for SBBC patients receiving synchronous bilateral hypofractionated radiotherapy (SBHRT) and to compare them with patients treated with synchronous bilateral normofractionated RT schedule (SBNRT). MATERIALS AND METHODS: From April 2016 to March 2020, 39 SBBC patients were referred to our institution. Patients were divided according to their prescription dose: Group A: 50 Gy/25fx (fractions), B: 60-64 Gy/25fx, C: 40.05 Gy/15fx; D: 48 Gy/15fx. Toxicity was evaluated using Common Terminology Criteria for Adverse Events (CTCAE)v.5.0. RESULTS: 34 patients were finally evaluated. Median follow-up was 24 months for NF schedule and 9 months for HF schedule. In the HF schedule, no acute side-effects > G2 were observed and no dermatitis was reported in 6th month´s assessments. 95% of patients have no evidence of disease and only 1 patient presented local relapse in the first mammography after RT. No distant failures or deaths were observed. Regarding dosimetric issues, the inter-patient average Dmean for the heart was: Group A: 5.0 Gy (4.6-5.5), Group B: 4.4 Gy (4.1-5.4), Group C: 4.8 Gy (4.5-5.1) and Group D: 5.3 Gy (4.4-5.6). For the lungs, the inter-patient average Dmean was: Group A: 10.8 Gy (9.8-12.2), Group B: 11.5 Gy (11.3-12), Group C: 9.8 Gy (9.3-10.5) and Group D: 10.5 Gy (10-11.3). CONCLUSIONS: This is the first study reporting the safety, feasibility, and tolerability of 40.05 Gy/15fx over 3 weeks for the treatment of SBBC patients. Further study with larger accrual is mandatory.

Modeling esophageal protection from radiofrequency ablation via a cooling device: an analysis of the effects of ablation power and heart wall dimensions.

BACKGROUND: Esophageal thermal injury can occur after radiofrequency (RF) ablation in the left atrium to treat atrial fibrillation. Existing methods to prevent esophageal injury have various limitations in deployment and uncertainty in efficacy. A new esophageal heat transfer device currently available for whole-body cooling or warming may offer an additional option to prevent esophageal injury. We sought to develop a mathematical model of this process to guide further studies and clinical investigations and compare results to real-world clinical data. RESULTS: The model predicts that the esophageal cooling device, even with body-temperature water flow (37 °C) provides a reduction in esophageal thermal injury compared to the case of the non-protected esophagus, with a non-linear direct relationship between lesion depth and the cooling water temperature. Ablation power and cooling water temperature have a significant influence on the peak temperature and the esophageal lesion depth, but even at high RF power up to 50 W, over durations up to 20 s, the cooling device can reduce thermal impact on the esophagus. The model concurs with recent clinical data showing an 83% reduction in transmural thermal injury when using typical operating parameters. CONCLUSIONS: An esophageal cooling device appears effective for esophageal protection during atrial fibrillation, with model output supporting clinical data. Analysis of the impact of ablation power and heart wall dimensions suggests that cooling water temperature can be adjusted for specific ablation parameters to assure the desired myocardial tissue ablation while keeping the esophagus protected.

Practical Heart Sparing Breast Cancer Radiation Therapy Using Continuous Positive Airway Pressure (CPAP) in Resource-Limited Radiation Oncology Clinics.

PURPOSE: The purpose of this study was to report experiences of practical heart sparing breast radiation therapy (RT) using continuous positive airway pressure (CPAP) in resource-limited radiation oncology clinics. PATIENTS AND METHODS: Twelve patients underwent computed tomography-simulations with both free-breathing (FB) and CPAP under the individual maximum tolerable air pressure. For each patient, left-sided breast RT plans (9 with breast only, 3 with breast and regional nodal stations) with FB and CPAP were created using 3-dimensional conformal RT (supine tangential or wide tangential RT fields) according to RTOG 1304. For daily RT, patients started CPAP in the patients waiting area for 15 minutes before entering the treatment room and continued CPAP during RT. Treatment setup times between breast RT with and without CPAP were compared. RESULTS: All patients tolerated CPAP well with 8 to 15 cm H2O of air pressure. Compared with FB, CPAP inflated the thorax and increased total lung volume by 35±16% (CPAP: 3136±751 vs. FB: 2354±657 cm, P<0.01); caudally displaced the heart by 1.8 cm (P<0.01); and decreased heart volume within tangential RT fields on computed tomography-simulation scans by 96±4% (1.4±2.5 vs. 21±17 cm, P=0.02) in all patients. Planning target volume coverage was acceptable in all RT plans. CPAP lowered mean dose (Dmean) to heart by 47±22% (2.5±1.5 vs. 5.4±3.3 Gy, P<0.01); heart volume receiving ≥25 Gy (V25) by 82±18% (2.2±2.6 vs. 9.1±7.1%, P<0.01); Dmean to left anterior descending coronary artery by 68±8% (4.7±1.9 vs. 14.8±3.3 Gy, P<0.01). CPAP decreased radiation dose to ipsilateral lung compared with FB: 9.1±5.8 versus 11.2±8 Gy (20% reduction, P=0.03) of Dmean; 15.7±12.5 vs. 20.5±17.5% (25% reduction, P=0.03) of V20. RT with CPAP did not increase treatment setup time compared with FB (week 1: 362±63 vs. 352±77 s; week 2 to 5: 217±13 vs. 201±14 s, all P>0.25). CONCLUSION: Novel use of CPAP allowed efficient and practical heart sparing breast RT without increasing infrastructural requirements in resource-limited radiation oncology clinics.

Cardiac autonomic responses and number of repetitions maximum after LED irradiation in the ipsilateral and contralateral lower limb.

The aim of this study was to verify the maximum number of repetitions, fatigue index, blood lactate concentration ([Lac]), and cardiac autonomic responses after LED irradiation (LEDI) in the ipsilateral and contralateral limb. Twelve male subjects (22.0 ± 3.86 years; weight 82.94 ± 12.58 kg; height 1.77 ± 0.05 m), physically active, took part in this study. The subjects underwent a one repetition maximum (1RM) test and performed four randomly experimental sessions in the horizontal leg press exercise, which consisted in four sets of maximum repetitions at 80% of 1RM. The subjects performed two experimental sessions applying LED active or placebo on ipsilateral limb and two experimental sessions applying LED active or placebo on contralateral limb prior exercise and in the interval of sets on quadriceps and hamstrings muscles. A number of repetitions and fatigue index were verified. [Lac] and heart rate variability (HRV) were collected during post-exercise recovery and analyzed. It was observed that active LEDI promoted an increase in maximal number of repetitions (LEDI = 44.4 ± 9.0 vs placebo = 39.9 ± 11.4; p < 0.05) and decreases the fatigue index (LEDI = 34.3 ± 21.8% vs placebo = 50.0 ± 26.6%; p < 0.05) comparing to placebo situation, only in the ipsilateral application. There were no differences on [Lac] and in HRV parameters comparing LEDI vs placebo on post-exercise recovery in both applications (p > 0.05). The LEDI improves performance only in the ipsilateral application, but there were no differences on [Lac] and cardiac autonomic responses after exercise for both the applications.

Amelioration of cardiac function and activation of anti-inflammatory vasoactive peptides expression in the rat myocardium by low level laser therapy.

Low-level laser therapy (LLLT) has been used as an anti-inflammatory treatment in several disease conditions, even when inflammation is a secondary consequence, such as in myocardial infarction (MI). However, the mechanism by which LLLT is able to protect the remaining myocardium remains unclear. The present study tested the hypothesis that LLLT reduces inflammation after acute MI in female rats and ameliorates cardiac function. The potential participation of the Renin-Angiotensin System (RAS) and Kallikrein-Kinin System (KKS) vasoactive peptides was also evaluated. LLLT treatment effectively reduced MI size, attenuated the systolic dysfunction after MI, and decreased the myocardial mRNA expression of interleukin-1 beta and interleukin-6 in comparison to the non-irradiated rat tissue. In addition, LLLT treatment increased protein and mRNA levels of the Mas receptor, the mRNA expression of kinin B2 receptors and the circulating levels of plasma kallikrein compared to non-treated post-MI rats. On the other hand, the kinin B1 receptor mRNA expression decreased after LLLT. No significant changes were found in the expression of vascular endothelial growth factor (VEGF) in the myocardial remote area between laser-irradiated and non-irradiated post-MI rats. Capillaries density also remained similar between these two experimental groups. The mRNA expression of the inducible nitric oxide synthase (iNOS) was increased three days after MI, however, this effect was blunted by LLLT. Moreover, endothelial NOS mRNA content increased after LLLT. Plasma nitric oxide metabolites (NOx) concentration was increased three days after MI in non-treated rats and increased even further by LLLT treatment. Our data suggest that LLLT diminishes the acute inflammation in the myocardium, reduces infarct size and attenuates left ventricle dysfunction post-MI and increases vasoactive peptides expression and nitric oxide (NO) generation.

Dosimetric comparison of normal structures associated with accelerated partial breast irradiation and whole breast irradiation delivered by intensity modulated radiotherapy for early breast cancer after breast conserving surgery.

PURPOSE: To assess the heart and lung dosimetry results associated with accelerated partial breast irradiation intensity-modulated radiotherapy (APBI-IMRT) and whole breast field-in-field intensity-modulated radiotherapy (WBI-FIF-IMRT). METHODS: A total of 29 patients with early-stage breast cancer after lumpectomy were included in this study. APBI-IMRT and WBI-FIF-IMRT plans were generated for each patient. The dosimetric parameters of ipsilateral lung and heart in both plans were then compared with and without radiobiological correction. RESULTS: With and without radiobiological correction, the volume of ipsilateral lung showed a substantially lower radiation exposure in APBI-IMRT with moderate to high doses (P < 0.05) but non-significant increases in volume of ipsilateral lung in 2.5 Gy than WBI-FIF-IMRT (P > 0.905).There was no significant difference in volume of ipsilateral lung receiving 1, 2.5, and 5 Gy between APBI-IMRT and WBI (P > 0.05) in patients with medial tumor location, although APBI-IMRT exposed more lung to 2.5 and 5 Gy. APBI-IMRT significantly decreases the volume of heart receiving low to high doses in left-sided breast cancer (P < 0.05). CONCLUSION: APBI-IMRT can significantly spare the volume of heart and ipsilateral lung receiving moderate and high dose. Non-significant increases in volume of the ipsilateral lung exposed to low doses of radiation were observed for APBI-IMRT in comparison to WBI-FIF-IMRT, particularly in patients with medial tumor location. With the increasing interest in APBI-IMRT, our data may help clinicians individualize patient treatment decisions.

A novel technique for image-guided local heart irradiation in the rat.

In radiotherapy treatment of thoracic, breast and chest wall tumors, the heart may be included (partially or fully) in the radiation field. As a result, patients may develop radiation-induced heart disease (RIHD) several years after exposure to radiation. There are few methods available to prevent or reverse RIHD and the biological mechanisms remain poorly understood. In order to further study the effects of radiation on the heart, we developed a model of local heart irradiation in rats using an image-guided small animal conformal radiation therapy device (SACRTD) developed at our institution. First, Monte Carlo based simulations were used to design an appropriate collimator. EBT-2 films were used to measure relative dosimetry, and the absolute dose rate at the isocenter was measured using the AAPM protocol TG-61. The hearts of adult male Sprague-Dawley rats were irradiated with a total dose of 21 Gy. For this purpose, rats were anesthetized with isoflurane and placed in a custom-made vertical rat holder. Each heart was irradiated with a 3-beam technique (one AP field and 2 lateral fields), with each beam delivering 7 Gy. For each field, the heart was visualized with a digital flat panel X-ray imager and placed at the isocenter of the 1.8 cm diameter beam. In biological analysis of radiation exposure, immunohistochemistry showed γH2Ax foci and nitrotyrosine throughout the irradiated hearts but not in the lungs. Long-term follow-up of animals revealed histopathological manifestations of RIHD, including myocardial degeneration and fibrosis. The results demonstrate that the rat heart irradiation technique using the SACRTD was successful and that surrounding untargeted tissues were spared, making this approach a powerful tool for in vivo radiobiological studies of RIHD. Functional and structural changes in the rat heart after local irradiation are ongoing.

Effect of black grape juice against heart damage from acute gamma TBI in rats.

The aim of this study was to evaluate the potential positive effect of black grape juice (BGJ) on lipid peroxidation considering Total Body Irradiation (TBI) in Wistar rats. As a potential feasible means of evaluation in situ, blood serum lactate dehydrogenase (LDH) levels were evaluated as a marker for heart damage from acute radiation syndrome (ARS). Twenty rats were divided into four groups, two of them being irradiated by gamma-rays from a Co-60 source. Animals were treated by gavage with 2 mL per day of BGJ or placebo for one week before and 4 days after 6 Gy whole body gamma-irradiation, when they were euthanasiated. LDH on serum and lipid peroxidation on heart tissue were evaluated. High concentration of metabolites from lipid peroxidation in heart, and high LDH level on serum were found only in gamma-irradiated group given placebo, mainly at the first 24 h after radiation. Phytochemical analysis of BGJ was performed by determining total phenolics, flavonoids, and tannins followed by a high-performance liquid chromatography (HPLC/DAD) analysis, which showed resveratrol as the major constituent. Results suggest that BGJ is a good protective candidate compound against heart damage from ARS and its effects suggest its use as a radiomodifier.

Caspase-3 activation and increased procollagen type I in irradiated hearts.

The caspase-3-cleaved presence was evaluated in this study in the heart of irradiated rats, during the decline of ventricular function. Female Wistar rats were irradiated with a single dose of radiation (15 Gy) delivered directly to the heart and the molecular, histological and physiological evaluations were performed at thirteen months post-irradiation. The expressions of procollagen type I, TGF-ß1 and caspase-3-cleaved were analyzed using Western blotting. Cardiac structural and functional alterations were investigated by echocardiography and electron microscopy. In the irradiated group, the levels of procollagen type I, TGF-ß1 and caspase-3-cleaved are increased. Significant histological changes (degeneration of heart tissue and collagen deposition) and functional (reduced ejection fraction) were observed. Data suggest that the cardiac function decline after exposure to ionizing radiation is related, in part, to increased collagen and increased caspase-3-cleaved.

Estudo dos efeitos da radioterapia no tecido cardíaco e sua associação com o metabolismo energético / Study of the effects of radiation therapy in cardiac tissue and its association with energy metabolism

Durante o tratamento radioterápico para tumores localizados na região torácica, parte do coração frequentemente é incluída no campo de tratamento e pode receber doses de radiação ionizante, significativas em relação à terapêutica. A irradiação do coração é capaz de causar importantes complicações cardíacas ao paciente, caracterizadas por alterações funcionais progressivas cerca de 10 a 20 anos após a exposição do órgão. Devido ao seu alto grau de contração e grande consumo energético, o tecido cardíaco é altamente dependente do metabolismo oxidativo que ocorre nas mitocôndrias. Danos as estas organelas podem levar ao decréscimo da produção de energia, tendo um impacto direto sobre a performance cardíaca. Ainda, ao interagir com as células, a radiação ionizante pode gerar uma série de eventos bioquímicos que conduzem a uma resposta celular complexa, em que muitas proteínas parecem estar envolvidas. Tendo em vista tais conhecimentos, o objetivo do estudo foi avaliar o aspecto ultraestrutural do tecido cardíaco, a bioenergética mitocondrial e a expressão diferencial de proteínas após irradiação. Os ensaios foram realizados em amostras de tecido cardíaco de ratos Wistar irradiados com dose única de 20 Gy direcionada ao coração. As análise tiveram início 4 e 32 semanas após irradiação. A análise ultraestrutural foi realizada através de microscopia eletrônica de transmissão. A respiração mitocondrial foi mensurada em oxígrafo, a partir das taxas de consumo de oxigênio pelas fibras cardíacas. A identificação de proteínas diferencialmente expressas foi investigada através de duas técnicas proteômicas: 2D-DIGE (2-D Fluorescence Difference Gel Electrophoresis) e uma abordagem label-free seguida de espectrometria de massas. Os resultados mostraram que os efeitos tardios da radiação incluem a degeneração das mitocôndrias e das unidades contráteis do tecido cardíaco, disfunções na cadeia respiratória mitocondrial e expressão diferencial de proteínas...

During radiotherapy for tumors located at toracic region, part of the heart is often included in the treatment field and may receive a significant ionizing radiation dose comparing to the therapeutics. Heart irradiation is able to cause substantial cardiac complications to patient, characterized by functional progressive changes from 10 to 20 years after the exposure of the organ. Because of its high level of contraction and large energetic consumption, cardiac tissue is highly depending on oxidative metabolism which happens at mitochondrias. Damage to these organelles can lead to decreased energy production, having a direct impact on cardiac performance. Even when interacting with cells, ionizing radiation can generate a series of biochemical events that lead to a complex cellular response, in many proteins seem to be involved. Given this knowledge, the aim of the study was to evaluate the ultrastructural appearance of cardiac tissue, mitochondrial bioenergetics and differential expression of proteins after irradiation. The tests were performed on samples of cardiac tissue of rats irradiated with single dose of 20 Gy directed to the heart. The analysis started 4 to 32 weeks after irradiation. The ultrastructural analysis was performed by transmission electron microscopy. Mitochondrial respiration was measured in oxigraph from rates of oxygen consumption by cardiac fibers. The identification of differentially expressed proteins was investigated using two proteomic techniques: 2D-DIGE (2-D Fluorescence Difference Gel Electrophoresis) and a label-free approach followed by mass spectrometry. The results showed that the late effects of radiation include degeneration of mitochondria and contractile units of cardiac tissue, dysfunction in the mitochondrial respiratory chain and differential expression of proteins involved in energy metabolism of carbohydrates, lipids and phosphocreatine. In general, the study showed that the cardiac irradiation damages...

Up-regulation of angiotensin-converting enzyme and angiotensin II type 1 receptor in irradiated rats.

PURPOSE: To investigate changes in cardiac functional parameters and the cardiac expression of angiotensin-converting enzyme (ACE), angiotensin II type 1 receptor (AT1), procollagen type I (proc-I) and transforming growth factor-ß1 (TGF-ß1) in rats irradiated at heart. MATERIAL AND METHODS: Male Wistar rats were irradiated with a single dose of radiation (0, 5, 10 and 15 Gray [Gy]) delivered directly to the heart and the molecular evaluations were performed at various times post-irradiation (two days, 15 days and four months). The expression of ACE, AT1, proc-I and TGF-ß1 were analysed using Real Time-Polymerase Chain Reaction (RT-PCR) and/or Western blotting. Cardiac structural and functional alterations were investigated at the four-month time point by echocardiography and by quantitative methods (stereology). RESULTS: Rats irradiated with 15 Gy showed a modest reduction in the ejection fraction. Cardiac proc-I, TGF-ß1, ACE and AT1 were also measurably increased. CONCLUSIONS: Irradiated rat hearts show simultaneous elevations in renin-angiotensin system components AT1 and ACE and cardiac remodeling markers proc-I and TGF-ß1.

Expressão da proteína tgfbeta1 em coração irradiado in vivo / In vivo evaluation of expression of TGFbeta1 in the irradiated heart

OBJETIVO: Avaliar, no coração, por imuno-histoquímica, a localização das proteínas TGFbeta1 latente e TGFbeta1 ativa, se ocorre ativação radioinduzida da proteína TGFbeta1 latente, e a distribuição das fibras colágenas em diversos períodos de tempo após irradiação. MATERIAIS E MÉTODOS: Trinta e dois camundongos isogênicos (C57BL) foram divididos em dois grupos: GI (não irradiado), com 12 animais, e GII (irradiado), com 20 animais. Os animais do GII receberam radiação gama (telecobaltoterapia, 60Co, com rendimento de 0,97 Gy/min., dose única de 7 Gy em corpo inteiro). Os camundongos dos grupos I e II foram sacrificados por estiramento cervical nos períodos de 1, 14, 30 e 90 dias após irradiação. RESULTADOS: Os corações irradiados apresentaram: 1) alterações nucleares e diminuição das estriações das células musculares cardíacas; 2) aumento significante da deposição de fibras colágenas aos 90 dias depois da irradiação; 3) ativação da proteína TGFbeta1 latente em cardiomiócitos e células do conjuntivo depois da irradiação. CONCLUSÃO: Nossos resultados mostram a importância da proteína TGFbeta1 no processo de fibrose cardíaca radioinduzida e sugerem que células do parênquima (cardiomiócitos) e do conjuntivo podem participar deste mecanismo atuando como fontes da proteína TGFbeta1 ativa.

OBJECTIVE: To assess the latent and active TGFb1 localization in the heart, to evaluate whether or not radiation induces latent TGFb1 activation, and to study the distribution of collagen fibers in the irradiated heart. MATERIALS AND METHODS: Thirty-two C57BL mice were randomly assigned in two groups: GI (non irradiated animals) and GII (irradiated animals). The mice from GII received a single whole-body radiation dose of 7Gy, using a 60Co source at a dose rate of 0.97 Gy/min. The animals were sacrificed by cervical dislocation at 1, 14, 30 and 90 days after irradiation. RESULTS: The irradiated hearts showed: 1) nuclear changes and muscle cells with decreased striations; 2) significant increase in the collagen deposition 90 days after irradiation; 3) latent TGFb1 activation in the cardiomyocytes and connective tissue cells after irradiation. CONCLUSION: Our results show the importance of TGFbeta1 protein in the process of radiation-induced heart fibrosis and suggest that cardiomyocytes and connective cells may play a role in this mechanism acting as cellular sources of active TGFbeta1

F 18-FDG heart uptake in oncologic pet studies

Background: PET scanning with F-18 FDG is a useful technique to detect malignant lesions. The goal of this work to analyze the frequency of increased heart uptake in routine PET oncologic studies and to correlate F-18 FDG Standardized Uptake Values (SUV) to blood glucose level (BGL)

Sistema para el monitoreo de pacientes y la sincronización de lasa imágenes de um tomógrafo de RMI de 0.1 T / System for patients monitoring and syncronization of tomographic images of NMR of 0.1 T

El sistema para el monitoreo continuo de pacientes usado en el tomógrafo cubano de RMI Giroimag - 02 es presentado. Se detallan los métodos de obtención y procesamiento de las bioseñales así como el modo en que se establecen los sincronismos y el formato de visualización de las ondas

Abstract A Continuous monitrning system for cuban NMR Scanner Giroimag 02 is presenteei. Biosignal processing is explained and thc methods uscd for data adquisition is presenteei. Also. syncronism anel the fonnat of wave displaying are shown

[Histologic findings in laser radiation of myocardial pericrater in dogs]. / Hallazgos histológicos en la irradiación por laser sobre el miocardio canino pericrater.

Laser beam constitutes a potential therapy in modern cardiology. Although its myocardial effects are known, they have been insufficiently evaluated at the surviving myocytes zone surrounding the evaporated crater. In order to assess myocyte cellular and organelar damage, we studied 8 isolated canine hearts radiated with different intensities by a CO2He laser beam 2.4, 3.5, 5, 15, 25, 30 and 40 Watts, varying the exposition time from 1 to 6 sec. Color photographs from the post-radiated lesions on front and depth were obtained. Their volumes were measured applying the cylinder and the cut out-conus formulas according to the shape of the lesions and then the involved tissues were embedded in paraffin for histological studies. Previously, samples of the lesions were fixed in glutaraldehyde for ultrastructural studies. Volumes of the craters were from 0.0004 to 19.57 mm3. Three layers were observed: a) a carbonized internal lining which measured x 15 microns in thickness; b) a coagulation necrotic zone ("gruyere cheese-like"), 70 microns thickness; c) finally more peripherally, a layer consisting of myocytes with patchy homogeneous cytoplasm, and scare positivity for the Barbeito López Trichome Stain (a positive technique in cases of myocardial damage). Ultrastructurally, crater peripherical cells showed cytosol and mitochondrial edema without membrane disruptions. These findings suggest that myocytes surrounding the laser beam crater, show reversible lesions. Therefore laser beam apperrs a safe procedure to be used in myocardium.