High Signal Resolution Pulse Oximetry as a Prognostic Indicator of Radiotherapy Toxicity: A Pilot Study.

INTRODUCTION: Radiotherapy plays a prominent role in the multidisciplinary treatment of cancers. Despite new irradiation techniques, radiation-induced cardiotoxicity remains a leading cause of morbidity and mortality. Therefore, prognostic indicators of radiotherapy toxicity are essential. This study aimed to investigate the influence of applied radiotherapy on the pulse wave recording and thereby on cardiovascular health, as well as to assess whether high signal resolution (HSR) pulse oximetry could be used as a prognostic indicator of radiotherapy toxicity. METHODS: A total of 19 patients treated with radiotherapy to the lung or left breast were analyzed. Pulse oximetry was performed on all eligible patients (before and after the administration of a radiation dose) using the PULS-HSR program, which increases the resolution of the pulse wave recording. RESULTS: Among the analyzed variables, we found the total dose administered to the target, as well as the treatment duration, significantly positively correlated with the change in ventricle/aorta volume ratio. The ventricle/aorta volume ratio parameter is the ratio between the area under the HSR pulse wave generated by the contraction of the left ventricle until the aortic valve closes and the area of the HSR pulse wave responsible for expansion and contraction of the aorta. CONCLUSION: The pilot study indicates HSR pulse oximetry, especially the ventricle/aorta volume ratio parameter, as a potential prognostic indicator of toxicity from radiation for breast and lung cancers.

The Estimation of Blood Paramagnetic Center Changes during Burns Management with Biodegradable Propolis-Nanofiber Dressing.

The evolution of the paramagnetic center system in blood during the healing of skin burn wounds dressed with a biodegradable apitherapeutic nanofiber dressing was examined. The aim of this study was to determine the changes in paramagnetic centers in blood during the influence of apitherapeutic nanofiber dressings on the healing process. The blood samples were tested before burn infliction (day 0) and, respectively, on the 10th and 21st days of the experiment. Paramagnetic centers in the blood of the pig used as the model animal were examined with an X-band (9.3 GHz) electron paramagnetic resonance spectroscopy. The EPR spectra were measured with Bruker spectrometer at 230 K with a modulation frequency of 100 kHz. The EPR lines of the high spin Fe3+ in methemoglobin, high spin Fe3+ in transferrin, Cu2+ in ceruloplasmin, and free radicals were observed in the multicomponent spectra of blood. For the application of the apitherapeutic nanofiber dressing, the amplitudes of the EPR signals of Fe3+ in methemoglobin were similar up to 10 days. For the experiment with the apitherapeutic formulation, the heights of EPR signals of Fe3+ in transferrin were lower after 10 days and 21 days of therapy, compared to day 0. For the application of the apitherapeutic formulation the signals of Cu2+ in ceruloplasmin and free radicals, strongly decreased after 10 days of therapy, and after 21 days it increased to the initial values characteristic for day 0. The apitherapeutic formulation caused that after 21 days the EPR spectrum of Cu2+ in ceruloplasmin and free radicals was considerably high. The apitherapeutic formulation interaction after 10 days and after 21 days of therapy resulted in the low EPR lines of Fe3+ in methemoglobin. EPR spectra of blood may be useful for presentation of the changes in its paramagnetic centers during the healing process of the burn wounds.

ESR Method in Monitoring of Nanoparticle Endocytosis in Cancer Cells.

Magnetic nanoparticles are extensively studied for their use in diagnostics and medical therapy. The behavior of nanoparticles after adding them to cell culture is an essential factor (i.e., whether they attach to a cell membrane or penetrate the membrane and enter into the cell). The present studies aimed to demonstrate the application of electron spin resonance (ESR) as a suitable technique for monitoring of nanoparticles entering into cells during the endocytosis process. The model nanoparticles were composed of magnetite iron (II, III) oxide core functionalized with organic unit containing nitroxide radical 4-hydroxy-TEMPO (TEMPOL). The research studies included breast cancer cells, as well as model yeast and human microvascular endothelial cells. The results confirmed that the ESR method is suitable for studying the endocytosis process of nanoparticles in the selected cells. It also allows for direct monitoring of radical cellular processes.

ESR as a monitoring method of the interactions between TEMPO-functionalized magnetic nanoparticles and yeast cells.

Potential application of magnetic nanoparticles as drug carriers in medical treatment requires prior determination of their effects on cells. In this work different spin labels and magnetic nanoparticles functionalized with spin labels as well as their interaction with yeast cells were investigated using electron spin resonance (ESR) method. ESR was demonstrated to be a suitable method for monitoring of magnetic core and attached spin labels. Particular emphasis was placed on characterization of endocytosis and redox processes running inside the cell, resulting in recombination of spin labels. Such data could only be obtained at reduced temperature of ESR measurements.

EPR Spectroscopic Examination of Different Types of Paramagnetic Centers in the Blood in the Course of Burn Healing.

The multicomponent electron paramagnetic resonance spectra of the blood during healing of skin burned wounds treated with a new generation biodegradable dressings containing poly(lactide-co-glycolide) were analysed. The evolution of different types of paramagnetic centers in the blood with time of healing was determined. The EPR spectra of the blood samples at 230 K temperature were measured at 1, 10, and 21 days after burning of the pig skin. The EPR lines of the following paramagnetic centers: the high-spin Fe3+ in methemoglobin (line I), high-spin Fe3+ in transferrin (line II), and Cu2+ in ceruloplasmin and free radicals (line III) were observed in the X-band (9.3 GHz) spectra of the blood. The multicomponent structure of the EPR spectra of the tested blood samples depended on the time of the healing of the burned wounds. The amount of the high-spin Fe3+ in methemoglobin (line I) in the blood decreased after 21 days of the healing of the burned wounds. The amount of the high-spin Fe3+ in transferrin (line II) slightly increased after 21 days of therapy with the basis. The amount of Cu2+ in ceruloplasmin and free radicals (line III) in the blood was very high after 10 days of therapy. At the first day of the healing of the burned wounds, the highest amount of the high-spin Fe3+ in methemoglobin (line I), the relatively lower amounts of the high-spin Fe3+ in transferrin (line II), and Cu2+ in ceruloplasmin and free radicals (line III) existed in the blood. In the medium phase (after 10 days) of the healing of the burned wounds, the extremely higher amounts of Cu2+ in ceruloplasmin and free radicals (line III) appeared in the blood. In the last phase (after 21 days), only the low differences between the amounts of the high-spin Fe3+ in methemoglobin (line I), the high-spin Fe3+ in transferrin (line II), and Cu2+ in ceruloplasmin and free radicals (line III) were observed. The present study may serve as a starting point for the development of a new technique for monitoring molecular complexes containing iron Fe3+ (methemoglobin, transferrin) or copper Cu2+ ions (ceruloplasmin) and free radicals in the blood during wound healing.

The influence of radiotherapy on ceruloplasmin and transferrin in whole blood of breast cancer patients.

Ceruloplasmin and transferrin are proteins which play a potential role in the process of breast cancer development. These molecules contain Cu2+ (ceruloplasmin) or Fe3+ ions (transferrin) and thus constitute paramagnetic centers, which can be studied using electron paramagnetic resonance method. The aim of the study was to determine how paramagnetic centers in whole blood of breast cancer patients change under the influence of radiation therapy. Samples of whole blood were taken from 17 women with breast cancer treated with radiotherapy. The measurements were carried out at 170 K using X-band electron paramagnetic resonance (EPR) spectrometer Bruker EMX-10. Two distinct EPR lines, derived from high-spin Fe3+ in transferrin and Cu2+ from ceruloplasmin, were revealed in all frozen samples. The amplitude and integrated intensity of the EPR signal from Cu2+ in ceruloplasmin significantly decreased in all patients after the delivery of the radiation fraction. When comparing the integral intensity of the signal from Fe3+ in transferrin, three different situations were identified which are patient specific: a significant increase, an insignificant change, or a significant decrease after the irradiation. A decreased level of Cu2+ from ceruloplasmin in patients after radiotherapy means a low level of ceruloplasmin in the plasma or an increased content of reduced Cu+ ions. Differences in the integrated intensity of the EPR signal from transferrin translate directly into the amount of bound iron. The observed changes could indicate how well the organism fights against cancer and how easily it adapts to the situation of biochemical stress.

Measurement of free radicals using electron paramagnetic resonance spectroscopy during open aorto-iliac arterial reconstruction.

BACKGROUND: Aortic cross-clamping during abdominal aortic aneurysm (AAA) open repair leads to development of ischemia-reperfusion injury. Electron paramagnetic resonance spectroscopy (EPR) spin-trapping is a valuable method of direct measurement of free radicals. The objective of the study was to evaluate the results of EPR as a direct method of free radical measurement and degree of inflammatory response in open operative treatment of patients with AAA and aorto-iliac occlusive disease (AIOD). MATERIAL/METHODS: The study was performed on a group of 32 patients with AAA and 25 patients with AIOD scheduled for open repair. Peripheral venous blood for EPR spectroscopy and for SOD, GPx, ox-LDL, Il-6, TNF-alfa, CRP, and HO-1 were harvested. Selected parameters were established accordingly to specified EPR and immunohistochemical methods and analyzed between groups by Mann-Whitney U test and Wilcoxon matched-pairs signed-ranks test with Bonferroni correction. RESULTS: Free radicals level was correlated with the time of the aortic cross-clamping after the reperfusion of he first and second leg in AAA (r=0.7; r=0.47). ox-LDL in AAA decreased 5 min after reperfusion of the first leg (32.99 U/L, range: 14.09-77.12) and 5 min after reperfusion of the second leg (26.75 U/L, range: 11.56-82.12) and 24 h after the operation (25.85 U/L, range: 14.29-49.70). HO-1 concentration increased to above the level before intervention 24 h after surgery. The activities of GPx and SOD decreased 5 min after the first-leg reperfusion in AAA. Twenty-four hours after surgery, inflammatory markers increased in AAA to CRP was 14.76 ml/l (0.23-38.55), IL-6 was 141.22 pg/ml (84.3-591.03), TNF-alfa was 6.82 pg/ml (1.76-80.01) and AIOD: CRP was 18.44 mg/l (2.56-33.14), IL-6: 184.1 pg/ml (128.46-448.03), TNF-alfa was 7.74 pg/ml (1.74-74.74). CONCLUSIONS: EPR spin-trapping demonstrates temporarily elevated level of free radicals in early phase of reperfusion, leading to decrease antioxidants in AAA. Elevated free radical levels decreased 24 h after surgery due to various endogenous antioxidants and therapies.

EPR investigation of UV light effect on calcium carbonate powders with different grain sizes.

This study is based on investigation of calcium carbonate powders with different grain sizes exposed to UV light. Calcium carbonate is widely used in many branches of industry, e.g. as a filler for polymer materials; therefore, knowing its properties, among them also its reaction to UV light, is essential. Samples of powdered calcium carbonate with average grain sizes of 69 and 300 nm and 2.1, 6, 16, 25 µm were used in this investigation. Measurements were performed at room temperature using EPR X-band spectrometer, and they have shown the additional signals induced by the light from Hg lamp. The effect of annealing of the micro-grain samples was also studied. The spectra of four micro-grain samples after irradiation are similar, but there are differences between them and the other two powders, which could be related to the different sizes of their grains. Further studies based on these preliminary results may prove useful in research of photodegradation of CaCO3-filled materials, as well as helpful in increasing the accuracy of dating of archaeological and geological objects.

Synthesis and in vitro and in vivo evaluations of poly(ethylene glycol)-block-poly(4-vinylbenzylphosphonate) magnetic nanoparticles containing doxorubicin as a potential targeted drug delivery system.

The main challenge in antitumor chemotherapy is to enhance the curative effect and minimize the adverse effects of an anticancer drug. Administration of functionalized magnetic iron oxide nanoparticles is one of the strategies to improve sensitivity to cancer chemotherapy, and these nanoparticles are attractive materials that have been widely used in medicine for various applications, including diagnostic imaging and therapeutic applications. In this study, we describe the synthesis and characterization of drug-loaded iron oxide nanoparticles. Our aim was to obtain a biocompatible and injectable nanocarrier with anticancer activity. Iron oxide nanoparticles (IONs) were synthesized by alkali co-precipitation of iron salts followed by coating with our original surface modification agent, poly(ethylene glycol)-block-poly(4-vinylbenzylphosphonate) copolymer (PEG-PIONs). An anticancer drug doxorubicin (DOX), which clinical use is associated with cardiotoxicity, was loaded onto PEG-PIONs (PEG-PIONs/DOX), and to the best of our knowledge, this formulation showed higher drug encapsulation efficiency (drug loading capacity of the nanocarrier was 11.7%) than other formulations previously reported. PEG-PIONs/DOX had a hydrodynamic diameter of about 35nm and were stable in biological conditions over a period more than one month and showed stable and continuous in vitro drug release and antiproliferative effects on cancer cells. Fluorescent imaging indicated internalization of the PEG-PIONs/DOX in the cytoplasm of cancer cells. Biodistribution studies showed that PEG-PIONs/DOX preferentially accumulate in the tumor region via enhanced permeability and retention effect. In addition, analysis of the serum levels of enzymes indicated that PEG-PIONs/DOX reduced the cardiotoxicity associated with free DOX. These results indicate that PEG-PIONs/DOX have the potential for targeted delivery of antitumor drugs via systemic administration.

EPR Studies of DOPA-Melanin Complexes with Netilmicin and Cu(II) at Temperatures in the Range of 105-300 K.

The application of electron paramagnetic resonance (EPR) spectroscopy in pharmacy of melanin complexes with netilmicin and Cu(II) was presented. The continuous microwave saturation of EPR spectra of DOPA-melanin and the complexes was performed. EPR spectra were measured on an X-band (9.3 GHz) spectrometer at temperatures in the range of 105-300 K. Paramagnetic copper ions decrease the intensity of the EPR lines of melanin's free radicals. It was found that fast spin-lattice relaxation characterizes DOPA-melanin-Cu(II) complexes. Slow spin-lattice relaxation processes exist in melanin's paramagnetic centers of DOPA-melanin and DOPA-melanin-netilmicin, [DOPA-melanin-netilmicin]-Cu(II), [DOPA-melanin-Cu(II)]-netilmicin complexes. Spin-lattice relaxation processes are faster at higher temperatures. The homogeneous broadening of EPR lines for melanin complexes was observed. The practical consequences of differences between paramagnetic properties of melanin complexes with netilmicin and the complexes with Cu(II) were discussed.

Free Radicals, Salicylic Acid and Mycotoxins in Asparagus After Inoculation with Fusarium proliferatum and F. oxysporum.

Electron paramagnetic resonance was used to monitor free radicals and paramagnetic species like Fe, Mn, Cu generation, stability and status in Asparagus officinalis infected by common pathogens Fusarium proliferatum and F. oxysporum. Occurrence of F. proliferatum and F. oxysporum, level of free radicals and other paramagnetic species, as well as salicylic acid and mycotoxins content in roots and stems of seedlings were estimated on the second and fourth week after inoculation. In the first term free and total salicylic acid contents were related to free radicals level in stem (P = 0.010 and P = 0.033, respectively). Concentration of Fe(3+) ions in porphyrin complexes (g = 2.3, g = 2.9) was related to the species of pathogen. There was no significant difference between Mn(2+) concentrations in stem samples; however, the level of free radicals in samples inoculated with F. proliferatum was significantly higher when compared to F. oxysporum.

EPR Study of Iron Ion Complexes in Human Blood.

Electronic states of iron ion complexes in human blood from patients with melanoma have been investigated by electron paramagnetic resonance (EPR). The measurements were performed at liquid nitrogen temperature (77 K) on an X-band EPR spectrometer. Numerous types of iron paramagnetic centers have been identified. In several kinds of protein complexes exemplified by methemoglobin, transferrin or ferritin, various forms of trivalent iron have been found. Three groups of patients with typical EPR spectra have been individualized. These groups differed in types and concentration of paramagnetic centers in peripheral blood. A good correlation has been found between the EPR results, the total iron ion complexes concentration and transferrin saturation.

Two-dimensional imaging of two types of radicals by the CW-EPR method.

The CW-EPR method of image reconstruction is based on sample rotation in a magnetic field with a constant gradient (50 G/cm). In order to obtain a projection (radical density distribution) along a given direction, the EPR spectra are recorded with and without the gradient. Deconvolution, then gives the distribution of the spin density. Projection at 36 different angles gives the information that is necessary for reconstruction of the radical distribution. The problem becomes more complex when there are at least two types of radicals in the sample, because the deconvolution procedure does not give satisfactory results. We propose a method to calculate the projections for each radical, based on iterative procedures. The images of density distribution for each radical obtained by our procedure have proved that the method of deconvolution, in combination with iterative fitting, provides correct results. The test was performed on a sample of polymer PPS Br 111 (p-phenylene sulphide) with glass fibres and minerals. The results indicated a heterogeneous distribution of radicals in the sample volume. The images obtained were in agreement with the known shape of the sample.