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Nowak R Baranowska-Bosiacka I Stefańska B Machaliński B Hłyńczak AJ Tarasiuk J 《Acta biochimica Polonica》2005,52(4):953-957
Multidrug resistance (MDR) of tumour cells is related to the overexpression of ATP-dependent pumps responsible for the active efflux of antitumour agents out of resistant cells. Benzoperimidine and anthrapyridone compounds exhibit comparable cytotoxic activity against sensitive and MDR tumour cells. They diffuse extremely rapidly across the plasma membrane and render the ATP-dependent efflux inefficient. Such uptake could disturb an energy metabolism of normal cells possessing an elevated level of ATP-dependent proteins, especially erythrocytes having a high level of the MRP1, MRP4 and MRP5 proteins. In this study the effect of five antitumour agents: benzoperimidine (BP1), anthrapyridones (CO1, CO7) and reference drugs used in the clinic: doxorubicin (DOX) and pirarubicin (PIRA), on the energetic state in human erythrocytes has been examined. These compounds have various types of structure and kinetics of cellular uptake (slow--DOX, CO7, moderate--PIRA, fast--BP1, CO1) resulting in their different ability to saturate ATP-dependent transporters. The energetic state of erythrocytes was examined by determination of purine nucleotide contents (ATP, ADP, AMP), NAD(+) and values of adenylate energy charge (AEC) using an HPLC method. It was found that the level of nucleotides as well as the AEC value of erythrocytes were not changed during 24 h of incubation with these agents independently of their structure and ability to saturate ATP-dependent pumps. This is a very promising result in view of their potential use in the clinic as antitumour drugs against multidrug resistant cancers. 相似文献
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Ewelina Węglarz-Tomczak Marcin Poręba Anna Byzia Łukasz Berlicki Bogusław Nocek Rory Mulligan Andrzej Joachimiak Marcin Drąg Artur Mucha 《Biochimie》2013
Neisseria meningitides is a gram-negative diplococcus bacterium and is the main causative agent of meningitis and other meningococcal diseases. Alanine aminopeptidase from N. meningitides (NmAPN) belongs to the family of metallo-exopeptidase enzymes, which catalyze the removal of amino acids from the N-terminus of peptides and proteins, and are found among all the kingdoms of life. NmAPN is suggested to be mostly responsible for proteolysis and nutrition delivery, similar to the orthologs from other bacteria. 相似文献
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Bogusŀaw Pawŀwski 《Human Evolution》1998,13(1):65-72
Human newborns and infants have morphological and physiological traits protecting them against hypothermia. These traits are
unusual for primates, with some of them rarely seen in other mammals evolving in an African environment. We can include the
following: 1.) A non-allometric, bigger size of the newborn, resulting in the decrease of surface to body mass ratio (S/W).
2.) Greater amount of subcutaneous fat tissue (SFT) increasing insulation. 3.) Greater amount of brown fat tissue increasing
nonshivering thermogenesis. 4.) Active thermoregulation when sleeping. 5.) Thermal balance moved in the direction of heat
conservation in a few months' old babies.
I here present a hypothesis that it was the risk of nocturnal hypothermia in open habitats of late Pliocene that was the selective
pressure promoting evolutionary emergence of these traits inHomo erectus. The inverse radiation at night in open habitats causes strong gradient of temperatures. In effect the temperatures near
the ground (even in the tropics) can be low enough to endanger newborns and infants with hypothermia. If earlyHomo was naked, slept on the ground and if mortality of their babies caused by hypothermia was high, then selection pressures
could have promoted those traits protecting infants against the risk of hypothermia. Since the most important traits (1. &
2.) in respect of heat conservation, depend on mother size, it is postulated that they appeared when female body size increased
dramatically i.e. duringHomo erectus stage of human phylogeny. 相似文献
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Rabbit hemorrhagic disease virus (RHDV) which causes a highly contagious disease of wild and domestic rabbits belongs to the family Caliciviridae. It is a small, positive single-stranded RNA virus with a genome of 7.5 kb and has a diameter of approximately 40 nm. In negatively stained electron micrographs the virus shows typical calicivirus morphology with regularly arranged cup-shaped structures on the surface. It is a major pathogen of rabbits in many countries. Vp60 - a coat protein of molecular mass around 60 kDa is the major antigen of RHDV. It is present as 90 dimeric units per virion particle. We have expressed VP60 gene in the baculovirus system with the aim to use it as a potential vaccine against RHDV and a diagnostic reagent in immunological tests. cDNA of the vp60 gene of strain SGM, was cloned into a baculovirus transfer vector as full-length gene, as well as truncated gene lacking 600 5'-terminal nucleotides. The sequence of SGM VP60 differed markedly from that of the reference strain. Full-length recombinant VP60 protein from the SGM strain self-assembled to form virus-like particles (VLPs). These particles observed by electron microscopy were morphologically similar to native virions and were able to agglutinate human group 0 erythrocytes. After immunization the recombinant particles induced RHDV-specific antibodies in rabbits and guinea pigs. Rabbits immunized with the VLPs were fully protected against challenge with a virulent RHDV. 相似文献
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Konopska B Gburek J Gołab K Warwas M 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2007,146(4):482-488
Chicken cystatin, a homologue of human cystatin C, like other low-molecular-weight proteins is metabolized by renal proximal tubule cells. However, the precise mechanism(s) of this process has not been elucidated yet. To characterize chicken cystatin binding to renal brush-border membranes, the incubation of fluorescein labelled protein with rat cortical homogenate was performed. Saturation-dependent and reversible binding with low affinity (Kd = 3.67–4.07 μM) and high capacity (Bmax = 2.32–2.79 nmol/mg) was observed. Bovine albumin was the most potent competitor (Ki = 0.7 μM) among other megalin/cubilin ligands tested. The presence of Ca+ 2 ions was necessary to effective cystatin binding by brush-border membranes. Obtained data strongly support the hypothesis that chicken cystatin is a novel ligand for megalin/cubilin receptors tandem on proximal tubular cells. 相似文献
8.
Bone marrow (BM) was for many years primarily regarded as the source of hematopoietic stem cells. In this review we discuss current views of the BM stem cell compartment and present data showing that BM contains not only hematopoietic but also heterogeneous non-hematopoietic stem cells. It is likely that similar or overlapping populations of primitive non-hematopoietic stem cells in BM were detected by different investigators using different experimental strategies and hence were assigned different names (e.g., mesenchymal stem cells, multipotent adult progenitor cells, or marrow-isolated adult multilineage inducible cells). However, the search still continues for true pluripotent stem cells in adult BM, which would fulfill the required criteria (e.g. complementation of blastocyst development). Recently our group has identified in BM a population of very small embryonic-like stem cells (VSELs), which express several markers characteristic for pluripotent stem cells and are found during early embryogenesis in the epiblast of the cylinder-stage embryo. 相似文献
9.
Rudnicka J Kowalkowski T Ligor T Buszewski B 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(30):3360-3366
A method for qualitative and quantitative the determination of concentrations volatile organic compounds (VOCs) in human breath samples using solid phase microextraction (SPME) and gas chromatography-time of flight-mass spectrometry (GC-TOF/MS) has been carried out. They are employed for the preconcentration, separation and analysis of biological samples. The technique to rapid determination compounds present in human air, at the level of parts per billion (ppb) is applied. This method was optimized and evaluated. It showed linear correlations ranging from 0.83 to 234.05 ppb, limit of detection in the range of 0.31 to 0.75 ppb and precision, expressed as the RSD, was less then 10.00%. The unique combination of statistical methods allowed reduce the number of compounds to significant ones only and indicate the potential way to find the biomarkers of the lung cancer. Presented an analytical and statistical methods for detection composition of exhaled air could be applied as a potential non-intrusive tool for screening of lung cancer. 相似文献
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