Optimisation in HDR brachytherapy

New HDR machines supplied with stepping source systems give us an additional opportunity to optimise source distribution by modeling source dwell time. Different optimization algorithms are implemented in the commercial planning systems connected with HDR machines. The choice of proper optimization procedures is basic for Quality Assurance in brachytherapy planning.The main ideas of optimization algorithms implemented in PLATO system are presented.Some examples of gynaecological, intralumenal and interstitial brachytherapy are analyzed. Nonoptimised and “geometrically” optimized interstitial implants are compared. The advantages of optimization are discussed on the basic of dose-volume histograms. The danger of wrong optimization is also discussed.This work is supported by KBN Grant No 8T11E0440

Activation of Carotid Baroreceptors and Respiratory Resistance: Disappearance of the Respiratory Component of Baroreflex in the Course of Aging

Wstęp Jednym z efektorów odruchu z baroreceptorów zatokowych są drogi oddechowe. Na uwagę zasługuje wpływ pobudzenia baroreceptorów zatokowych na opór oddechowy u ludzi w różnym wieku. Materiał i metody Badaniom poddano 125 zdrowych mężczyzn w różnych grupach wiekowych. U wszystkich badanych analizowano odpowiedź sercową (wydłużenie odstępu R-R EKG) i zmiany oporu oddechowego w odpowiedzi na pobudzenie baroreceptorów zatok szyjnych podciśnieniem aplikowanym od zewnątrz na okolicę zatok szyjnych. Opór oddechowy mierzono metodą oscylacyjną. Wyniki W młodszych grupach wiekowych (21-40 lat) obserwowano spadek oporu obwodowego w odpowiedzi na pobudzenie baroreceptorów tętniczych. Reakcja ta była stopniowo coraz mniej wyraźna u badanych z coraz starszych grup wiekowych, a u osób w wieku 51-70 lat całkowicie zanikła. Odpowiedź sercowa była mniejsza w kolejnych grupach wiekowych. Wnioski Uzyskane wyniki świadczą o zmniejszającej się wraz z wiekiem efektywności odruchu z baroreceptorów zatokowych, obejmującej zarówno komponent sercowy, jak i oddechowy odruchu.Background Previous study shows a respiratory effector of carotid baroreceptor activation: the respiratory resistance. In the present study the age-related changes of respiratory response to carotid baroreceptor activation were studied. Material and methods 125 healthy men 21-70 years old were involved in the study. The heart responses (the increase in R-R interval) and reflex changes of respiratory resistance were analysed during activation of carotid baroreceptors. Results In the younger groups of subjects (21-40) a brief decrease of respiratory resistance was observed in response to carotid baroreceptors activation. In the course of aging we found a decrease of heart response and a disappearance of respiratory response. Conclusions We suggest that both components of carotid baroreceptors reflex: cardiac and respiratory, are impaired during biological aging

REST mediates resolution of HIF-dependent gene expression in prolonged hypoxia

The hypoxia-inducible factor (HIF) is a key regulator of the cellular response to hypoxia which promotes oxygen delivery and metabolic adaptation to oxygen deprivation. However, the degree and duration of HIF-1α expression in hypoxia must be carefully balanced within cells in order to avoid unwanted side effects associated with excessive activity. The expression of HIF-1α mRNA is suppressed in prolonged hypoxia, suggesting that the control of HIF1A gene transcription is tightly regulated by negative feedback mechanisms. Little is known about the resolution of the HIF-1α protein response and the suppression of HIF-1α mRNA in prolonged hypoxia. Here, we demonstrate that the Repressor Element 1-Silencing Transcription factor (REST) binds to the HIF-1α promoter in a hypoxia-dependent manner. Knockdown of REST using RNAi increases the expression of HIF-1α mRNA, protein and transcriptional activity. Furthermore REST knockdown increases glucose consumption and lactate production in a HIF-1α- (but not HIF-2α-) dependent manner. Finally, REST promotes the resolution of HIF-1α protein expression in prolonged hypoxia. In conclusion, we hypothesize that REST represses transcription of HIF-1α in prolonged hypoxia, thus contributing to the resolution of the HIF-1α response

Evaluation of glyceraldehyde-3-phosphate, prolylpeptidyl isomerase A, and a set of stably expressed genes as reference mRNAs in urate crystal inflammation

ABSTRACT

Cell cycle-dependent phosphorylation of pRb-like protein in root meristem cells of Vicia faba

The retinoblastoma tumor suppressor protein (pRb) regulates cell cycle progression by controlling the G1-to-S phase transition. As evidenced in mammals, pRb has three functionally distinct binding domains and interacts with a number of proteins including the E2F family of transcription factors, proteins with a conserved LxCxE motif (D-type cyclin), and c-Abl tyrosine kinase. CDK-mediated phosphorylation of pRb inhibits its ability to bind target proteins, thus enabling further progression of the cell cycle. As yet, the roles of pRb and pRb-binding factors have not been well characterized in plants. By using antibody which specifically recognizes phosphorylated serines (S807/811) in the c-Abl tyrosine kinase binding C-domain of human pRb, we provide evidence for the cell cycle-dependent changes in pRb-like proteins in root meristems cells of Vicia faba. An increased phosphorylation of this protein has been found correlated with the G1-to-S phase transition

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 Fe3+ ions in porphyrin complexes (g = 2.3, g = 2.9) was related to the species of pathogen. There was no significant difference between Mn2+ concentrations in stem samples; however, the level of free radicals in samples inoculated with F. proliferatum was significantly higher when compared to F. oxysporum