The unique feature of nuclear accidents with neutron exposure is the induced radioactivity in body tissues. For dosimetry purposes, the most important stable isotopes occurring in human body, which can be activated by neutrons, are 23 Na and 32 S. The respective activation reactions are as follows:23Na(n,γ)24Na and32S(n,p)32P. While sodium occurs in human blood, sulfur is present in human hair. In order to verify the practical feasibility of this dosimetry technique in conditions of our laboratory, samples of human blood and hair were irradiated in a channel of a training reactor VR-1.24Na activity was measured by gamma-ray spectrometry.32P activity in hair was measured by means of a proportional counter. Based on neutron-spectrum calculation, relationships between neutron dose and induced activity were derived for both blood and hair.
- MeSH
- dávka záření MeSH
- krev účinky záření MeSH
- lidé MeSH
- neutrony * MeSH
- radioaktivita MeSH
- radioizotopy fosforu analýza MeSH
- radioizotopy sodíku MeSH
- radiometrie metody MeSH
- síra analýza MeSH
- sodík analýza MeSH
- únik radioaktivních látek MeSH
- vlasy, chlupy účinky záření MeSH
- záření gama MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Autologous cell therapy (ACT) is a new treatment method for diabetic patients with critical limb ischemia (CLI) not eligible for standard revascularization. After intramuscular injection of bone marrow-derived mononuclear cells local arteriogenesis in the ischemic tissue occurs. Studies assessing visualization of this therapeutic vasculogenesis after ACT by novel imaging techniques are lacking. The aim of our study was to assess the effect of ACT on possible metabolic changes and perfusion of critically ischemic limbs using (31)P magnetic resonance spectroscopy ( (31)P MRS) and its possible correlation with changes of transcutaneous oxygen pressure (TcPO(2)). Twenty-one patients with diabetes and no-option CLI treated by ACT in our foot clinic over 8 years were included in the study. TcPO(2) as well as rest (phosphocreatine, adenosine triphosphate and inorganic phosphate) and dynamic (mitochondrial capacity and phosphocreatine recovery time) (31)P-MRS parameters were evaluated at baseline and 3 months after cell treatment. TcPO(2) increased significantly after 3 months compared with baseline (from 22.4±8.2 to 37.6±13.3 mm Hg, p=0.0002). Rest and dynamic (31)P MRS parameters were not significantly different after ACT in comparison with baseline values. Our study showed a significant increase of TcPO(2) on the dorsum of the foot after ACT. We did not observe any changes of rest or dynamic (31)P MRS parameters in the area of the proximal calf where the cell suspension has been injected into.
- MeSH
- autologní transplantace metody MeSH
- bérec diagnostické zobrazování krevní zásobení patologie MeSH
- ischemie diagnostické zobrazování metabolismus terapie MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie metody MeSH
- následné studie MeSH
- radioizotopy fosforu MeSH
- transplantace kostní dřeně MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
BACKGROUND: Heart failure (HF) is often associated with iron deficiency (ID). Skeletal muscle abnormalities are common in HF, but the potential role of ID in this phenomenon is unclear. In addition to hemopoiesis, iron is essential for muscle bioenergetics. We examined whether energetic abnormalities in skeletal muscle in HF are affected by ID and if they are responsive to intravenous iron. METHODS AND RESULTS: Forty-four chronic HF subjects and 25 similar healthy volunteers underwent 31P magnetic resonance spectroscopy of calf muscle at rest and during exercise (plantar flexions). Results were compared between HF subjects with or without ID. In 13 ID-HF subjects, examinations were repeated 1 month after intravenous ferric carboxymaltose administration (1000 mg). As compared with controls, HF subjects displayed lower resting high-energy phosphate content, lower exercise pH, and slower postexercise PCr recovery. Compared with non-ID HF, ID-HF subjects had lower muscle strength, larger PCr depletion, and more profound intracellular acidosis with exercise, consistent with an earlier metabolic shift to anaerobic glycolysis. The exercise-induced PCr drop strongly correlated with pH change in HF group ( r=-0.71, P<0.001) but not in controls ( r=0.13, P=0.61, interaction: P<0.0001). Short-term iron administration corrected the iron deficit but had no effect on muscle bioenergetics assessed 1 month later. CONCLUSIONS: HF patients display skeletal muscle myopathy that is more severe in those with iron deficiency. The presence of ID is associated with greater acidosis with exercise, which may explain early muscle fatigue. Further study is warranted to identify the strategy to restore iron content in skeletal muscle.
- MeSH
- acidóza metabolismus patofyziologie MeSH
- bérec MeSH
- biologické markery krev MeSH
- časové faktory MeSH
- deficit železa MeSH
- dospělí MeSH
- energetický metabolismus * účinky léků MeSH
- intravenózní podání MeSH
- isometrická kontrakce * MeSH
- izotopy fosforu * MeSH
- kosterní svaly účinky léků metabolismus patofyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie metody MeSH
- maltosa aplikace a dávkování analogy a deriváty MeSH
- prediktivní hodnota testů MeSH
- senioři MeSH
- srdeční selhání diagnóza farmakoterapie metabolismus patofyziologie MeSH
- studie případů a kontrol MeSH
- výsledek terapie MeSH
- zátěžový test * MeSH
- železité sloučeniny aplikace a dávkování MeSH
- železo krev MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Type I diabetes mellitus (DM1) is a complex disease with adverse effects on organs and tissues despite compensation by insulin treatment. The goal of our study was to study how kidney diseases change (31)P MR parameters of muscle metabolism in DM1 patients with respect to gender. 51 DM1 patients (19 m/14 f without and 13 m/5 f with nephropathy) and 26 (14 m/12 f) healthy volunteers were examined using (31)P magnetic resonance spectroscopy at 3T tomograph at rest, and during and after a calf muscle exercise. The exercise consisted of a six-minute plantar flexion using a pedal ergometer followed by a six-minute recovery. It is reflected by reduced relative beta-ATP and increased Pi and phosphodiester signals to phosphocreatine (PCr) at rest and prolongation of the PCr recovery time after the exercise. Measurement on healthy volunteers indicated differences between males and females in pH at the rest and after the exercise only. These differences between patients groups were not significant. We have proven that nephropathy affects the metabolism in diabetic patients and our results confirm significant difference between patients with and without nephropathy. Gender differences in pH were observed only between male and female healthy volunteers.
- MeSH
- diabetes mellitus 1. typu komplikace metabolismus MeSH
- diabetické nefropatie etiologie metabolismus MeSH
- dospělí MeSH
- energetický metabolismus MeSH
- izotopy fosforu MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie MeSH
- mladý dospělý MeSH
- sexuální faktory MeSH
- studie případů a kontrol MeSH
- svaly metabolismus MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Neutron field from the p+Be interaction was investigated at the NPI CAS for a proton beam energy of 35 MeV and thick beryllium target. Broad neutron spectra at close source-to-sample distances were determined using the multi-foil activation technique. Two large sets of dosimetry foils containing the Ni, Co, Au, In, Ti, Al, Y, Lu, Nb and Fe were irradiated at a distance of 74 mm at direct neutron beam axis and at a distance of 34 mm from beam axis. Supporting Monte-Carlo MCNPX calculations of the irradiation system were performed as well. From measured reaction rates, the neutron energy spectra at both positions were reconstructed employing the modified version of the SAND-II unfolding code and activation cross-section data from the EAF-2010 library. At the position of irradiated samples, the total fast neutron flux reaches the value up to 1010 cm-2 s-1, and the neutron field is utilizable for radiation hardness study and integral benchmark experiments within the International Fusion Material Irradiation Facility (IFMIF) program.
The constructions of super high (3T) and ultra high field (7T) magnetic resonance (MR) imagers in the past decade have enabled many MR imaging and spectroscopy experiments with other nuclei than protons. The paper summarizes the basis of in vivo dynamic 31P MR spectroscopy for biomedical and clinical applications. The calculations of quantitative parameters of muscular metabolism, such as pH, mitochondrial capacity, ADP concentration, time constant of phosphocreatine recovery and others, are shown. The construction of ergometers for the whole body magnetic resonance systems is described. Examples of typical data processing and evaluation are demonstrated.
- Klíčová slova
- dynamická in vivo ³¹P MR spektroskopie, mitochondriální kapacita,
- MeSH
- energetický metabolismus * MeSH
- ergometrie metody přístrojové vybavení MeSH
- glykolýza MeSH
- izotopy fosforu MeSH
- kinetika MeSH
- koncentrace vodíkových iontů MeSH
- kosterní svaly * MeSH
- kreatinkinasa, mitochondriální forma MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie * metody MeSH
- svalová síla MeSH
- tělesná námaha MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Chloroplast thylakoid membranes contain virtually all components of the energy-converting photosynthetic machinery. Their energized state, driving ATP synthesis, is enabled by the bilayer organization of the membrane. However, their most abundant lipid species is a non-bilayer-forming lipid, monogalactosyl-diacylglycerol; the role of lipid polymorphism in these membranes is poorly understood. Earlier 31P-NMR experiments revealed the coexistence of a bilayer and a non-bilayer, isotropic lipid phase in spinach thylakoids. Packing of lipid molecules, tested by fluorescence spectroscopy of the lipophilic dye, merocyanine-540 (MC540), also displayed heterogeneity. Now, our 31P-NMR experiments on spinach thylakoids uncover the presence of a bilayer and three non-bilayer lipid phases; time-resolved fluorescence spectroscopy of MC540 also reveals the presence of multiple lipidic environments. It is also shown by 31P-NMR that: (i) some lipid phases are sensitive to the osmolarity and ionic strength of the medium, (ii) a lipid phase can be modulated by catalytic hydrogenation of fatty acids and (iii) a marked increase of one of the non-bilayer phases upon lowering the pH of the medium is observed. These data provide additional experimental evidence for the polymorphism of lipid phases in thylakoids and suggest that non-bilayer phases play an active role in the structural dynamics of thylakoid membranes.
PURPOSE: To study theoretically the impact on cell survival of the radionuclide uptake rate inside tumor cells for a single administration of a radiopharmaceutical. METHODS: The instantaneous-uptake model of O'Donoghue ["The impact of tumor cell proliferation in radioimmunotherapy," Cancer 73, 974-980 (1994)] for a proliferating cell population irradiated by an exponentially decreasing dose-rate is here extended to allow for the monoexponential uptake of the radiopharmaceutical by the targeted cells. The time derivative of the survival curve is studied in detail deducing an expression for the minimum of the surviving fraction and the biologically effective dose (BED). RESULTS: Surviving fractions are calculated over a parameter range that is clinically relevant and broad enough to establish general trends. Specifically, results are presented for the therapy radionuclides Y-90, I-131, and P-32, assuming uptake half-times 1-24 h, extrapolated initial dose-rates 0.5-1 Gy h(-1), and a biological clearance half-life of seven days. Representative radiobiological parameters for radiosensitive and rapidly proliferating tumor cells are used, with cell doubling time equal to 2 days and α-coefficient equal to 0.3 and 0.5 Gy(-1). It is shown that neglecting the uptake phase of the radiopharmaceutical (i.e., assuming instantaneous-uptake) results in a sizeable over-estimation of cell-kill (i.e., under-estimation of cell survival) even for uptake half-times of only a few hours. The differences between the exponential-uptake model and the instantaneous-uptake model become larger for high peak dose-rates, slow uptakes, and (slightly) for long-lived radionuclides. Moreover, the sensitivity of the survival curve on the uptake model was found to be higher for the tumor cells with the larger α-coefficient. CONCLUSIONS: The exponential-uptake rate of the radiopharmaceutical inside targeted cells appears to have a considerable effect on the survival of a proliferating cell population and might need to be considered in radiobiological models of tumor cell-kill in radionuclide therapy.
- MeSH
- analýza přežití MeSH
- biologické modely MeSH
- nádory farmakoterapie patofyziologie MeSH
- proliferace buněk účinky léků MeSH
- protinádorové látky farmakokinetika farmakologie MeSH
- radiofarmaka farmakokinetika farmakologie MeSH
- radioizotopy fosforu farmakokinetika farmakologie MeSH
- radioizotopy jodu farmakokinetika farmakologie MeSH
- viabilita buněk účinky léků fyziologie MeSH
- vztah dávky záření a odpovědi MeSH
- yterbium farmakokinetika farmakologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Bone mineral nanoparticles, residing between collagenous fibres, contain a crystalline apatite core (CAC) covered by an amorphous hydrated surface layer (AHSL). The main objectives of this work were to characterize the nanoparticles of human bone mineral and their discrete CAC and AHSL regions and relate this information to bone diseases. This pilot study involved 18 postmenopausal women suffering from osteoarthritis together with osteoporosis or osteopenia. Trabecular tissue specimens were acquired from the femoral intertrochanteric region during total hip arthroplasty. The specimens of whole bone were examined by 31P solid-state NMR (ssNMR) to measure the concentration ratio of phosphorus in the AHSL and CAC locations, together with their 31P linewidths and spin-lattice relaxation times. It was found that the AHSL region of the studied specimens contained 13–24% apatite phosphorus. The magnitude, hydration and structural order of AHSL and CAC were dependent on the progress of the pertinent diseases. Thus, the 31P ssNMR spectroscopy can be used ex vivo to selectively analyse the discrete nanoapatite environments in whole bone specimens and possibly assist in postoperative medical diagnostics.
- MeSH
- apatity MeSH
- izotopy fosforu MeSH
- kosti a kostní tkáň chemie ultrastruktura MeSH
- kostní matrix ultrastruktura MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie metody přístrojové vybavení MeSH
- postmenopauzální osteoporóza patologie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
Závěrečná zpráva o řešení grantu Interní grantové agentury MZ ČR
1 svazek : ilustrace, tabulky ; 30 cm
Projekt sleduje dva základní cíle. Jednak jde o část metodickou, kdy se obnoví možnosti klinického vyšetřování pacientů pomocí in vivo fosforové MR spektroskopie, které není v současné době v ČR dostupné. Bude tak možné neinvazivně sledovat metabolismus svalové (včetně srdeční) nebo jaterní tkáně na základě intracelulárních koncentrací metabolitů obsahujících fosfor (např. ATP, fosfokreatin). Provedení výpočtů a kalibrací umožní použít metodu pro rutinní klinické vyšetřování svalů, srdce a jater včetně zátěžového testu s použitím ergometru. Prvním souborem nemocných budou pacienti s diabetem, u kterých se bude sledovat metabolismus kosterního svalu a jater v závislosti na klinickém stavu a léčbě, posléze se předpokládá rozšíření na skupinu pacientů s onemocněním srdce. Vzhledem k neinvazivnosti metody dojde ke zlepšení diagnostických možností bez invazivních zásahů a tím i komfortu vyšetření pro pacienty. V budoucnu by měla být metoda dostupná i pro další lékařské obory, které toto vyšetření vyžadují.; The project pursues two main goals. In the methodological part, the clinical examination of patients using in vivo 31P MR spectroscopy, which is currently not available in the Czech Republic, will be restored. Using this method, it will be possible to non-invasively study the metabolism of muscular (including heart muscle) and hepatic tissues based on the intracellular concentrations of metabolites containing phosphorus (ATP, PCr, etc.). Patients with diabetes and patients with heart disease will participate. The metabolism of skeletal muscle, the liver and heart with respect to clinical state and the applied treatment will be studied at rest and during exercise using an MR-compatible ergometer. Thanks to the non-invasiveness of the method, the diagnostic possibilities will be improved without any invasive interventions and, hence, with greater comfort for the examined patients. In the future the methods should be available for other branches of medicine where this type of examination is required.
