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Ferenc Ötvös Dmitry S. Gembitsky Richard F. Murphy Sándor Lovas 《International journal of peptide research and therapeutics》2007,13(1-2):329-336
Steric requirements of binding [Nle10]NKA(4–10) to NK-2 receptor were studied by introducing conformationally constrained amino acid analogs into its sequence.
Two series of [Nle10]NKA(4–10) analogs were synthesized to investigate (i) the significance of a putative β-turn in the receptor-ligand interaction by insertion of either (S)- or (R)-Gly8{ANC-2}Leu9 γ-lactams to mimic a β-turn constraint, and (ii) the effect of hindered rotation in the Φ, χ1 and χ2 dihedral angle space of the crucially important Phe6 which was replaced systematically with d-Phe, d- and l-Tyr, as well as with their conformationally constrained analogs, Tic, HOTic and β-MePhe. Competition binding experiments
with [3H]NKA were performed using cloned human NK-2 receptors expressed in CHO cells. The analog possessing only an (R)-Gly8{ANC-2}Leu9 constraint, had the same binding affinity as that of the parent peptide. The rank order of potency of the other analogs showed
a cumulative effect of different structural modifications in decreasing the binding affinity, i.e., when changing the configuration of the lactam ring to S, replacing Phe6 with constrained analogs, Tic or β-MePhe, changing the configuration of the amino acid at position six to d, and introducing a hydroxyl group on the aromatic ring.
Ferenc ?tv?s and Dmitry S. Gembitsky - Made an equal contribution.
Abbreviations used for amino acids and peptides follow the recommendations of the IUPAC-IUB Commission of Biochemical Nomenclature,
Eur. J. Biochem. (1984) 138, 9–37 相似文献
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Poly d/[3H]A-r5U/ type of synthetic models of bacteriophage DNAs containing thymine analogues were prepared by DNA polymerase and tested for stability against nucleases / was a n-alkyl group from methyl to pentyl/. The 5-pentyluracil-containing copolymer was found to be most stable: 50 % degradation with pancreatic DNase, spleen DNase, snake venom phosphodiesterase or micrococcal nuclease required 3–15 times as much time as that of poly d/A-T/. 相似文献
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A simple trypan blue-neutral red-Giemsa staining procedure for simultaneous evaluation of acrosome, sperm head, and tail membrane integrity and morphology has been used to evaluate equine spermatozoa. Some special characteristics and problems have arisen in evaluating stallion semen. One problem was the differentiation of intact vs. damaged sperm tails primarily in frozen and thawed samples. After freezing and thawing, a high percentage of spermatozoa with an unstained head and stained tail were observed. These cells are considered immotile. Therefore, unambiguous differentiation of intact vs. damaged sperm tail membrane is very important for evaluating semen quality. The aim of our study was to develop a method especially for stallion sperm to distinguish more accurately the different cell types. We compared Chicago sky blue 6B (CSB) to trypan blue (TB) for viability staining. CSB/Giemsa staining showed good repeatability and agreement with TB/Giemsa measurements. For densitometry analysis, individual digital images were taken from smears stained by CSB/Giemsa and by TB/Giemsa. A red-green-blue (RGB) histogram for each area of spermatozoa was drawn. Differences of means of RGB values of live vs. dead tails and separate live vs. dead heads from each photo were used to compare the two staining procedures. CSB produced similar live/dead sperm head differentiation and better tail differentiation. TB can be replaced by CSB and this results in more reliable evaluation. After staining with 0.16% CSB and 4 min fixation, 2-4 h Giemsa staining at 25-40 degrees C is recommended for stallion semen. 相似文献
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Dóra?Ujvárosy Veronika?Sebestyén Tamás?Pataki Tamás??tv?s István?L?rincz Gy?rgy?Paragh Zoltán?SzabóEmail authorView authors OrcID profile 《BMC cardiovascular disorders》2018,18(1):227
Background
Chest compression is a decisive element of cardio-pulmonary resuscitation (CPR). By applying a mechanical CPR device, compression interruptions can be minimised. We examined the efficiency of manual and device-assisted resuscitation as well as the effects of cardiovascular risk factors on the outcome of resuscitation.Methods
In our retrospective, randomised 3-year study the data of adult patients suffering non-traumatic, out-of-hospital, sudden cardiac death (SCD) were analysed (n?=?287). The data were retrieved by processing case reports, Utstein sheets and acute coronary syndrome sheets. We compared the data of patients undergoing manual (n?=?232) and device-assisted resuscitation (LUCAS-2, n?=?55). The primary endpoint was the on-site restoration of spontaneous circulation (ROSC).Results and conclusion
In 37% of the cases ROSC happened. With respect to ROSC an insignificantly more favourable tendency was demonstrated in the case of device-assisted resuscitation (p =?0.072). In the Lucas group, a higher success rate occurred even in the case of prolonged resuscitation. We found a better outcome in the Lucas group in the case of CPR started a longer time after the SCD (p?<?0.05). A positive correlation was established between age and unsuccessful resuscitation (p?=?<?0.017; r?=?0.125). An unfavourable correlation was observed between hypertension and the outcome of resuscitation (p?=?0.018; r?=?0.143). According to our results the presence of left ventricular hypertrophy poses 5.1-fold risk of unsuccessful CPR (CI: 4.97–5.29).Advanced age and structural heart diseases can play a role in the genesis of SCD. Importantly, left ventricular hypertrophy and hypertension negatively affect survival.8.
Taras P. Pasternak Krisztina Ötvös Mónika Domoki Attila Fehér 《Plant Growth Regulation》2007,51(2):109-117
The activation of cell division and oxidative stress responses has been investigated in the case of leaf protoplast-derived
cells. Initiation of protoplast culture was found to be associated with oxidative stress as indicated by the rate of H2O2 release into the medium and/or by catalase and ascorbate peroxidase activities. Both cell division frequency and the above
stress-related parameters were dependent on the exogenous auxin (2,4-dichlorophenoxyacetic acid, 2,4-D) concentrations used.
In addition, the well known oxidative stress-inducing agent paraquat (1 μM) could promote cell division at suboptimal auxin
concentration but not in the absence of exogenous auxin. The H2O2 scavenger dimethylthiourea and the NADPH oxidase inhibitor diphenyleneiodonium inhibited not only the activation of cellular
defense reactions but cell division as well. Based on the above experimental observations, it is suggested that exogenous
auxin (2,4-D) enhances cellular defense reactions in parallel with cell division activation. 相似文献
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J. Sági A. Szabolcs K. Ebinger L. Ötvös J. Balzarini E. De Clercq 《Nucleosides, nucleotides & nucleic acids》2013,32(8):1729-1742
Abstract The 2-amino derivatives of 5-ethyl-2′-deoxyuridine (EDU) and (E)-5-(2-bromovinyl)-2′-deoxyuridine (BVDU) have been synthesized and evaluated for anti-herpesvirus activity. They were at least 1000-fold less effective against herpes simplex virus replication than the parent compounds EDU and BVDU. The 5′-triphosphates of the 2-amino substituted EDU, BVDU and thymidine derivatives were also synthesized and examined on their substrate/inhibitor properties against different DNA polymerases. None of the compounds proved markedly inhibitory to HSV-1 DNA polymerase or cellular DNA polymerase a. Nor were they incorporated into the growing DNA chain. 相似文献
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L. Ötvös J. Sági Gy. Sági A. Szemzõ F. D. Tóth A. Jeney 《Nucleosides, nucleotides & nucleic acids》2013,32(6-7):1665-1666
Abstract Two series of alternating ODNs containing 5-n.alkyl-, alkenyl- and alkynyl-dU and -dC units have been prepared in order to study the kinetics of their hydrolysis by SV PDE and human serum, respectively. Both in (r5dUpdA)10 and (r5dCpdG)6 series the rate of hydrolysis decreased with increasing length of side-chain. Replacement of thymidines by 5-hexynyl-dU in different antisense oligomers resulted in considerably higher biological activity relative to that of the thymidine-containing counterparts. 相似文献