RESUMO
Oligonucleotides with 3'- and 5'-terminal 1-(beta-D-2'-deoxy-threo-pentafuranosyl)thymin residues (inversion at C3'-atom) were obtained by the automatic phosphoramidite synthesis. The modifications protect oligonucleotides from the nuclease degradation and do not affect the stability of nucleic acid duplexes.
Assuntos
Oligonucleotídeos Antissenso/química , Timidina/análogos & derivados , Sequência de Bases , Dados de Sequência Molecular , Oligonucleotídeos Antissenso/metabolismo , Timidina/análiseRESUMO
A series of model DNA-duplexes with a single break in one of the chains were studied. The efficiency of the new internucleotide bond formation by means of chemical ligation was shown to depend on the DNA structure in the nick site, decreasing in the following order: pyrimidine-pyrimidine > purine-pyrimidine > pyrimidine-purine > > purine-purine. This relationship is the most pronounced in duplexes with 5'-hydroxyl group as 3'-phosphate acceptor. For duplexes, containing non-complementary base pairs in the reaction centre, the yield of ligation products also depends on the nature of the interacting nucleotides.
Assuntos
DNA/química , Ácidos Nucleicos/química , Composição de Bases , Sequência de Bases , Dados de Sequência Molecular , Conformação de Ácido NucleicoRESUMO
Efficiency of the template-directed condensation of oligonucleotides depends on the nature of the nucleotide units to be joined. Fourteen out of sixteen dinucleotide combinations in double-stranded DNA were examined. Alterations of the reaction efficiency are identical for cyanogen bromide and 1-ethyl-3-(3'-dimethylaminopropyl)carbodiimide coupling reagents. Dependence of the chemical ligation efficiency on the DNA sequence-specific local conformation is discussed.
Assuntos
Ácidos Nucleicos/química , Oligonucleotídeos/química , Sequência de Bases , Brometo de Cianogênio/química , Etildimetilaminopropil Carbodi-Imida/química , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Moldes GenéticosRESUMO
Analysis of the clinical status of preterm newborns and the results of histochemical studies of the red cell catecholamine depositing function has led the authors to a conclusion that the Apgar score is reliable only in case of the newborn's critical condition. In slight and medium-severity asphyxia high red cell satiation with catecholamine granules was associated with a favorable outcome for the newborns. The authors claim that analysis of red cell catecholamine-depositing function is a sufficiently reliable diagnostic and prognostic criterion for the assessment of a preterm newborn's status.
Assuntos
Catecolaminas/sangue , Doenças do Prematuro/diagnóstico , Recém-Nascido Prematuro , Índice de Apgar , Asfixia Neonatal/diagnóstico , Eritrócitos/química , Humanos , Recém-Nascido , PrognósticoRESUMO
An artificial gene comprising 183 base pairs has been assembled by template-directed condensation of 35- to 53-membered oligodeoxyribo nucleotides with cyanogen bromide as a condensing agent. The reaction is complete within several minutes at 0 degrees C in buffer. The resulting mini-gene was cloned and expressed in vivo and in vitro. We have also found that the polymerase inhibition technique (toe-printing) is a good way to ascertain that translation initiation complexes form in the case of single-stranded DNAs as well. Thus, along with the fully chemical assembly of synthetic genes, a rapid and sufficiently reliable method for determining their ribosome-binding properties was developed.
Assuntos
Genes Sintéticos , Oligonucleotídeos/síntese química , Polidesoxirribonucleotídeos/síntese química , Sequência de Bases , Clonagem Molecular , Brometo de Cianogênio/química , DNA de Cadeia Simples/metabolismo , DNA Polimerase Dirigida por DNA/metabolismo , Dados de Sequência Molecular , Biossíntese de Proteínas/fisiologia , Ribossomos/metabolismo , Temperatura , Transcrição Gênica/fisiologiaRESUMO
Both cyanogen bromide (BrCN) and 1-ethyl-3-(3'-dimethylaminopropyl) carbodiimide may be used as coupling reagents for the template-directed assembly of DNA duplexes containing the sugar-phosphate backbone modification. Both reagents show similar ligation site structure-specific trend. Practical recommendations are given for selection of the condensing reagent depending on the properties of the duplex. Based on 31P NMR spectroscopy data, a scheme is suggested for BrCN activation of the nucleotide phosphomonoester group. Using both condensing reagents, we studied the condensation of oligonucleotides containing ribo-segments (from mononucleotide residue to full sequence) on the DNA template. Efficiency of the chemical ligation of RNA oligomers was shown to be much lower than that of DNA analogues. The coupling yield depends on the position of the RNA segment in the hybrid duplexes and on the position of the phosphate group in the nick.
Assuntos
Carbodi-Imidas/química , Brometo de Cianogênio/química , DNA/química , Ácidos Nucleicos Heteroduplexes , RNA/química , Sequência de Bases , Eletroforese em Gel de Poliacrilamida , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Moldes GenéticosRESUMO
The effect of various parameters of transcutaneous electrical neurostimulation (TENS) on changes in B-endorphin (BE) blood plasma level has been studied in the mother and fetus during premature labour. A dependence of changes in BE plasma level on the frequency regimen of the impulse current has been established. The data, on the one hand, demonstrate the regulating effect of high- and low- frequency TENS on BE blood level and, on the other hand, indicate the involvement of endogenous opioid fetus system, which enables it to endure labour-induced stress.
Assuntos
Analgesia Obstétrica , Sangue Fetal/química , Troca Materno-Fetal , Trabalho de Parto Prematuro/sangue , Estimulação Elétrica Nervosa Transcutânea , beta-Endorfina/sangue , Feminino , Humanos , GravidezRESUMO
The cholinergic system (CS) has been assessed in 60 women with a premature onset of labor and their newborns. Labor was regulated using transcutaneous electroneurostimulation (TENS) in 40 of them. High-frequency TENS (100-120 Hz) was used for uterine contractility stimulation and low-frequency (30 Hz) was used for relaxation. A pattern of contractile uterine activity was elucidated which indicated beneficial effects of TENS on abnormal conditions in premature labor. A correlation was found out between the maternal and neonatal SC status.
Assuntos
Acetilcolina/sangue , Acetilcolinesterase/sangue , Eritrócitos/metabolismo , Recém-Nascido/sangue , Trabalho de Parto Prematuro/terapia , Reflexo/fisiologia , Estimulação Elétrica Nervosa Transcutânea , Adolescente , Adulto , Feminino , Humanos , Trabalho de Parto Prematuro/fisiopatologia , Gravidez , Contração Uterina/fisiologiaRESUMO
Reflex relaxation using transcutaneous electroneurostimulation (TENS) has been employed in premature labor. Low-frequency TENS proved helpful in the prevention and therapy of un-coordinated uterine contractions and thus in the reduction of perinatal mortality.
Assuntos
Trabalho de Parto Prematuro/terapia , Tocólise/métodos , Estimulação Elétrica Nervosa Transcutânea/métodos , Contração Uterina/fisiologia , Adolescente , Adulto , Desenho de Equipamento , Feminino , Humanos , Trabalho de Parto Prematuro/fisiopatologia , Gravidez , Estimulação Elétrica Nervosa Transcutânea/instrumentação , U.R.S.S.RESUMO
Prostaglandin (PG) biosynthesis is promoted by enzyme activation induced by neurohormonal regulation, an important determinant of labor. However, contribution of PG to premature labor is largely uncertain. Maternal and fetal blood PGE levels have been determined during the reflex regulation of premature labor in 39 women and in 20 patients with spontaneous labor. The reflex regulation was performed as transcutaneous suprapubic and sacral electric stimulation. Comparison of PGE levels in the women and their newborns led to the conclusion that the reflex regulation of premature labour has modulating effects on PGE biosynthesis both in the mother and fetus, thereby modifying progress of labor.
Assuntos
Sangue Fetal/química , Trabalho de Parto Prematuro/sangue , Prostaglandinas E/sangue , Reflexo/fisiologia , Adolescente , Adulto , Feminino , Ruptura Prematura de Membranas Fetais/sangue , Ruptura Prematura de Membranas Fetais/terapia , Humanos , Trabalho de Parto Prematuro/terapia , Gravidez , Estimulação Elétrica Nervosa Transcutânea/métodosRESUMO
Labor induction in impending premature delivery complicated by premature rupture of the membranes is controversial. Problems arise both with choice of a mode of delivery and induction manoeuvres to be used in biologically premature delivery. The paper addresses the results with a reflex method of labor induction based on transcutaneous electroneurostimulation (TENS). An appropriate TENS regimen was found to be a highly efficient method of labor induction allowing one to reduce the incidence of perinatal complications.
Assuntos
Ruptura Prematura de Membranas Fetais/fisiopatologia , Trabalho de Parto Induzido/métodos , Miométrio/inervação , Trabalho de Parto Prematuro/fisiopatologia , Reflexo/fisiologia , Estimulação Elétrica Nervosa Transcutânea/métodos , Contração Uterina/fisiologia , Adolescente , Adulto , Feminino , Ruptura Prematura de Membranas Fetais/etiologia , Humanos , Trabalho de Parto Prematuro/complicações , GravidezRESUMO
Transcutaneous electric neurostimulation (TENS) as a mode of reflex therapy acts on the hypothalamic-pituitary control via the neuromediator system to modulate the activity of endocrine glands, metabolism and the immune status. Immunoglobulin and catecholamine levels and the activity of tumor necrosis factor have been assayed in umbilical blood sera of 25 preterm newborns who were delivered using TENS (n = 10) and spontaneously (n = 15). Comparison of clinical data and the findings of catecholamine and immune factor assays suggested that TENS in premature delivery improved fetal and neonatal adaptations to perinatal stresses and infection.
Assuntos
Glândulas Suprarrenais/fisiopatologia , Imunoglobulinas/análise , Recém-Nascido Prematuro/fisiologia , Trabalho de Parto Prematuro/terapia , Sistema Nervoso Simpático/fisiopatologia , Estimulação Elétrica Nervosa Transcutânea , Fator de Necrose Tumoral alfa/análise , Adaptação Fisiológica , Adolescente , Adulto , Feminino , Sangue Fetal/análise , Sangue Fetal/imunologia , Humanos , Recém-Nascido , Troca Materno-Fetal/fisiologia , Trabalho de Parto Prematuro/fisiopatologia , GravidezRESUMO
An artificial gene comprising 183 base pairs has been assembled by template-directed condensation of 35- to 53-membered oligodeoxyribonucleotides with cyanogen bromide as a condensing agent. The reaction is complete within several minutes at 0 degree C in buffer. The resulting gene was cloned into M13mp11 and sequenced using the Sanger sequencing procedure.
Assuntos
Genes Sintéticos , Oligodesoxirribonucleotídeos/síntese química , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Brometo de Cianogênio , DNA , Dados de Sequência Molecular , Mapeamento por Restrição , Moldes GenéticosAssuntos
Ruptura Prematura de Membranas Fetais/etiologia , Parto Obstétrico/métodos , Feminino , Ruptura Prematura de Membranas Fetais/diagnóstico , Ruptura Prematura de Membranas Fetais/terapia , Humanos , Recém-Nascido , Trabalho de Parto Induzido/métodos , Gravidez , Prognóstico , Síndrome do Desconforto Respiratório do Recém-Nascido/prevenção & controleRESUMO
Condensation of oligonucleotides containing ribonucleotide segments (from mononucleotide to full sequence) on DNA-template was studied, with cyanogen bromide and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as condensing agents. Efficiency of the chemical ligation of RNA oligomers was much lower than that of DNA analogues. The yield of chemical ligation products was found to depend on the position of RNA segment in the hybrid duplexes and on the position of the phosphate group in the nick. The oligoribonucleotide's length does not affect the yield of condensation products. A nick in 5S RNA loop was repaired by means of the chemical ligation method.
Assuntos
Ácidos Nucleicos Heteroduplexes , Autorradiografia , Sequência de Bases , Fenômenos Químicos , Química , Dicroísmo Circular , DNA/metabolismo , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Oligonucleotídeos/metabolismo , RNA/metabolismo , Moldes GenéticosRESUMO
Cyanogen bromide was found to condense oligodeoxyribonucleotides on a complementary template in aqueous solution. Optimum conditions for this vigorous and effective reaction were developed. CNBr proved to be useful for incorporation of phosphoramidate or pyrophosphate internucleotide bonds in DNA duplexes.
Assuntos
Brometo de Cianogênio/farmacologia , DNA/efeitos dos fármacos , Desoxirribonucleases de Sítio Específico do Tipo II , Oligodesoxirribonucleotídeos , Sequência de Bases , Fenômenos Químicos , Química , DNA Ligases/metabolismo , Enzimas de Restrição do DNA/metabolismo , Oligodesoxirribonucleotídeos/metabolismoRESUMO
The efficiency of chemical ligation method have been demonstrated by assembling a number of DNA duplexes with modified sugar phosphate backbone. Condensation on a tetradecanucleotide template of hexa(penta)- and undecanucleotides differing only in the terminal nucleoside residue have been performed using water-soluble carbodiimide as a condensing agent. As was shown by comparing the efficiency of chemical ligation of single-strand breaks in those duplexes, the reaction rate rises 70 or 45 times if the 3'-OH group is substituted with an amino or phosphate group (the yield of products with a phosphoramidate or pyrophosphate bond is 96-100% in 6 d). Changes in the conformation of reacting groups caused by mismatched base pairs (A.A, A.C) as well as the hybrid rU.dA pair or an unpaired base make the template-directed condensation less effective. The thermal stability of DNA duplexes was assayed before and after the chemical ligation. Among all of the modified duplexes, only the duplex containing 3'-rU in the nick was found to be a substrate of T4 DNA ligase.
Assuntos
DNA , Oligodesoxirribonucleotídeos , Composição de Bases , Sequência de Bases , Eletroforese em Gel de Poliacrilamida , Conformação de Ácido Nucleico , Oligodesoxirribonucleotídeos/síntese química , Radioisótopos de Fósforo , FosforilaçãoRESUMO
Cyanogen bromide was found to induce a smooth and highly efficient condensation of oligonucleotide blocks within DNA duplexes. This template-directed reaction proceeds in the aqueous solution at 0 degree C for 1-2 min. Cyanogen bromide catalyzes the formation not only of phosphodiester, but also of unnatural phosphoramide and pyrophosphate interoligomer bonds.