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1.
Acta Radiol Open ; 11(9): 20584601221128405, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36157917

RESUMEN

Background: Imaging of the portal vein prior to puncture for TIPS is essential. Purpose: With this study, we examined a modified retrograde portography with regard to the reliable representation of the portal vein. Material and Methods: Prospective evaluation of 65 TIPS interventions with regard to the delimitation of the portal vein and the exact parameters of retrograde portography such as catheter diameter and contrast medium volume per injection. Results: Retrograde portographies with a large-lumen catheter (10 F) and a large contrast medium volume (40 mL) were performed in 35/63 patients with significantly better delineation of the portal vein than when using 5 F catheters with 10 mL contrast medium. Conclusion: The so-called high volume retrograde portography leads to better delimitation of the portal vein during TIPS application.

2.
BJOG ; 116(2): 304-12, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19076963

RESUMEN

OBJECTIVE: To compare the assessment of endometrial maturation parameters in endometrial secretion samples obtained by a novel minimally invasive technique with those assessed in tissue biopsies. DESIGN: Prospective study. SETTING: University Hospital. POPULATION: Healthy female volunteers attending a gynaecological outpatient clinic. METHODS: Endometrial secretion fluid and tissue sampling 5 days after a spontaneous ovulation assessed with ultrasound. MAIN OUTCOME MEASURES: Progesterone (P) receptor, Ki-67 expression and the Noyes criteria were used to date endometrial biopsies. In the endometrial fluid samples, glycodelin A (GdA), leukaemia inhibitory factor (LIF) and P levels were analysed, and protein content and electrophoresis patterns were determined. RESULTS: All data were correlated to estradiol (E2) and P serum concentrations. The dating according to histology and immunohistochemical staining patterns correlated significantly with GdA levels (r=0.376, P=0.048) in endometrial fluid samples as well with serum levels of E2 (r=0.568, P=0.001) and P (r=0.408, P=0.023). No correlation was observed between tissue dating and LIF levels and protein content in endometrial fluid samples. CONCLUSIONS: The measurement of GdA in endometrial secretion samples may provide a less invasive method for assessing endometrial maturation in potential conception cycles without disrupting implantation.


Asunto(s)
Implantación del Embrión , Endometrio/fisiología , Adulto , Biomarcadores/análisis , Biomarcadores/sangre , Líquidos Corporales/química , Electroforesis en Gel Bidimensional , Endometrio/citología , Endometrio/metabolismo , Estudios de Factibilidad , Femenino , Glicodelina , Glicoproteínas/análisis , Humanos , Inmunohistoquímica , Antígeno Ki-67/análisis , Factor Inhibidor de Leucemia/análisis , Embarazo , Proteínas Gestacionales/análisis , Progesterona/análisis , Progesterona/sangre , Estudios Prospectivos , Receptores de Progesterona/análisis
3.
Reprod Biomed Online ; 17(4): 553-63, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18854111

RESUMEN

The objective of this study was to investigate the effect of ovarian stimulation for IVF on endometrial secretion and tissue markers of receptivity in the mid-luteal phase. In 10 oocyte donors, endometrial secretions and biopsies were sampled 5 days after spontaneous ovulation and oocyte retrieval in consecutive cycles. Four subjects received progesterone in the luteal phase of the stimulated cycles. Mid-luteal endometrial maturation in the stimulated cycle was compared with the spontaneous cycle, by histological dating, Ki-67, oestrogen receptor (ER) and progesterone receptor (PR) expression, secretion levels of leukaemia inhibitory factor (LIF), glycodelin A (GdA) and progesterone, and protein profile. No significant differences in histological markers, expression of Ki-67, PR, ER, secretion protein profiles or concentrations of LIF, GdA, or progesterone were observed when comparing natural with stimulated cycles. Progesterone supplementation of stimulated cycles was associated with significantly lower Ki-67 (P = 0.03) and ER (P = 0.04) expression compared with the non-supplemented stimulated cycle. In this pilot study, ovarian stimulation was not demonstrated to alter the studied markers of endometrial maturation in the mid-luteal phase.


Asunto(s)
Biomarcadores/metabolismo , Implantación del Embrión/fisiología , Endometrio/efectos de los fármacos , Endometrio/metabolismo , Fármacos para la Fertilidad Femenina/farmacología , Fase Luteínica/efectos de los fármacos , Inducción de la Ovulación , Adulto , Biomarcadores/sangre , Endometrio/fisiología , Femenino , Glicodelina , Glicoproteínas/metabolismo , Hormonas Esteroides Gonadales/sangre , Gonadotropinas/antagonistas & inhibidores , Humanos , Infertilidad/metabolismo , Infertilidad/terapia , Factor Inhibidor de Leucemia/metabolismo , Fase Luteínica/sangre , Fase Luteínica/fisiología , Embarazo , Proteínas Gestacionales/metabolismo
4.
J Reprod Immunol ; 74(1-2): 34-45, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17321596

RESUMEN

The semi-allogeneic fetus has to be tolerated by the maternal immune system. In mice, it has been shown that inhibiting indoleamine-dioxygenase (IDO) leads to fetal rejection, suggesting a central significance for IDO in establishing maternal tolerance. Consequently, we have analyzed IDO expression in human endometrium and decidua to determine whether it may be of significance in human reproduction. Endometrial (n=60) and decidual (n=68; first and second trimester) tissue samples and isolated cells were analyzed for IDO mRNA and protein expression by real-time PCR, Western blot and immunohistochemistry. IDO expression in the decidua of proven fertile women (n=34) was compared to women presenting with their first pregnancy (n=22) and women with a history of miscarriages (n=12). Expression of IDO was localized in glandular epithelial cells and scattered stromal leukocytes. Expression started at the mid-luteal phase in the menstrual cycle and was high until the second trimester of pregnancy. However, glandular expression of IDO decreased during the second trimester, whereas expression in villous trophoblast started at this time. There were no significant differences in decidual IDO expression between proven fertile women and women presenting with their first pregnancy or women with a history of miscarriages. From the expression pattern we conclude that IDO may play a central role in human pregnancies for the establishment of maternal tolerance of fetal antigens. Thereby, IDO expression may be needed in each pregnancy independently from prior pregnancies, and a history of miscarriage may not reflect a general deficiency in IDO expression.


Asunto(s)
Aborto Espontáneo/enzimología , Decidua/enzimología , Tolerancia Inmunológica , Indolamina-Pirrol 2,3,-Dioxigenasa/metabolismo , Primer Trimestre del Embarazo , Segundo Trimestre del Embarazo , Western Blotting , Decidua/citología , Decidua/metabolismo , Electroforesis en Gel de Poliacrilamida , Endometrio/enzimología , Femenino , Humanos , Inmunohistoquímica , Ciclo Menstrual , Placentación , Embarazo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
5.
Nucleic Acids Res ; 29(23): 4767-82, 2001 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-11726686

RESUMEN

Translational stop codon readthrough provides a regulatory mechanism of gene expression that is extensively utilised by positive-sense ssRNA viruses. The misreading of termination codons is achieved by a variety of naturally occurring suppressor tRNAs whose structure and function is the subject of this survey. All of the nonsense suppressors characterised to date (with the exception of selenocysteine tRNA) are normal cellular tRNAs that are primarily needed for reading their cognate sense codons. As a consequence, recognition of stop codons by natural suppressor tRNAs necessitates unconventional base pairings in anticodon-codon interactions. A number of intrinsic features of the suppressor tRNA contributes to the ability to read non-cognate codons. Apart from anticodon-codon affinity, the extent of base modifications within or 3' of the anticodon may up- or down-regulate the efficiency of suppression. In order to out-compete the polypeptide chain release factor an absolute prerequisite for the action of natural suppressor tRNAs is a suitable nucleotide context, preferentially at the 3' side of the suppressed stop codon. Three major types of viral readthrough sites, based on similar sequences neighbouring the leaky stop codon, can be defined. It is discussed that not only RNA viruses, but also the eukaryotic host organism might gain some profit from cellular suppressor tRNAs.


Asunto(s)
Codón de Terminación/genética , Terminación de la Cadena Péptídica Traduccional , Virus ARN/genética , ARN de Transferencia/fisiología , Animales , Emparejamiento Base , Secuencia de Bases , Regulación Viral de la Expresión Génica , Datos de Secuencia Molecular , ARN del Cloroplasto/genética , ARN de Transferencia/química , ARN Viral/química , ARN Viral/fisiología
6.
Mol Cell Endocrinol ; 235(1-2): 39-50, 2005 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-15866426

RESUMEN

Many mammary tumors express estrogen receptors (ER) and progesterone receptors (PR), and there is increasing evidence that progestins influence gene expression of breast tumor cells. To analyse the impact of progestins on breast cancer cells, we compared (a) the expression of two cytokines, involved in tumor progression, and searched (b) for differentially regulated genes by a microarray, containing 2400 genes, on T47D breast cancer cells cultured for 6 days with 17beta-estradiol (E2) or E2+medroxyprogesterone acetate (E2+MPA). Lower amounts of PDGF and TNFalpha were found in culture supernatants of E2+MPA treated T47D cells. MPA addition induced a 2.8-3.5-fold increase of the mRNA expression of (a) tristetraprolin, which is involved in the posttranscriptional regulation of cytokine biosynthesis, and (b) zinc-alpha2-glycoprotein and Na, K-ATPase alpha1-subunit, which both resemble differentiation markers of breast epithelium. In contrast, the mRNA expression of lipocalin 2, which promotes matrixmetalloproteinase-9 activity, was decreased five-fold in E2+MPA treated cells. Our data show that the expression of genes from various functional gene families is regulated differentially by E2 and E2+MPA treatment in T47D cells. This suggests that exogenous progestins applied for therapy and endogenous changes of the progesterone levels during the menstrual cycle both influence breast cancer pathophysiology.


Asunto(s)
Neoplasias de la Mama/genética , Estradiol/farmacología , Acetato de Medroxiprogesterona/farmacología , Línea Celular Tumoral , Receptor alfa de Estrógeno/metabolismo , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Análisis por Micromatrices , Factor de Crecimiento Derivado de Plaquetas/metabolismo , ARN Mensajero/metabolismo , Receptores de Progesterona/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Necrosis Tumoral alfa/metabolismo
7.
Endocrinology ; 131(5): 2446-60, 1992 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-1425442

RESUMEN

The objective of this study was to determine preimplantational effects of progesterone antagonists (PA) on the cell biology of the endometrium, on corpus luteum (CL) function and on the complex interactions between these two organs. The PA onapristone (ZK 98.299) or lilopristone (ZK 98.734) was given to pseudopregnant rabbits at days 5, 6, and 7 p.hCG. Three treatment protocols were investigated: Exp I, onapristone or lilopristone treatment only; Exp II, onapristone treatment after hysterectomy at day 1 p.hCG; Exp III, onapristone treatment together with 17 beta-estradiol, which represents the ultimate luteotropic hormone in the rabbit. In Exp I, onapristone and lilopristone gave rise to endometrial regression (inhibition of epithelial proliferation and differentiation, increase of apoptosis). Simultaneous addition of 17 beta-estradiol in Exp III did not alter these findings. A rapid luteolysis was found in Exp I. In Exp II and III, however, onapristone was unable to impair luteal development and function. Due to the unaffected CL in Exp III and due to the 17 beta-estradiol substitution, the endometrium was capable of starting a new transformation, which met all requirements for receptivity at day 12 p.hCG. Transfers of day 4 p.c. blastocysts from untreated donors into such delayed secretion recipient rabbits at days 12 p.hCG resulted in normal implantations and normal embryonic development. Contrary to Exp III, the missing of any luteotropic substitutions in Exp I resulted in a complete inhibition of further uterine transformation. The present findings suggest that PA can exert a direct inhibitory effect on the endometrium, which is followed by an indirect luteolytic effect via endometrial mediators. The simultaneous addition of a proper luteotropic signal to the PA protocol results in survival of CL. Furthermore, this prolongation of the CL life span can be interpreted as a functional dissociation of the endometrium from the CL.


Asunto(s)
Cuerpo Lúteo/fisiología , Endometrio/fisiología , Estrenos/farmacología , Gonanos/farmacología , Progesterona/antagonistas & inhibidores , Animales , División Celular/efectos de los fármacos , Cuerpo Lúteo/citología , Cuerpo Lúteo/ultraestructura , Electroforesis en Gel de Poliacrilamida , Transferencia de Embrión , Endometrio/citología , Endometrio/ultraestructura , Femenino , Inmunohistoquímica , Microscopía Electrónica , Microscopía Electrónica de Rastreo , Ovario/citología , Ovario/fisiología , Ovario/ultraestructura , Conejos , Radioinmunoensayo , Receptores de Estrógenos/análisis , Receptores de Progesterona/análisis , Uteroglobina/análisis
8.
Endocrinology ; 129(1): 312-22, 1991 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-2055191

RESUMEN

There is evidence from previous studies that progesterone antagonists (antigestagens) modify estrogen responses at endometrial and myometrial levels without having affinity to the estrogen receptor (ER). The purpose of the present study was to investigate the influence of the antigestagen onapristone (ZK 98 299) on the uterus in ovariectomized (OVX) estradiol (E2)-substituted rabbits (3.0 micrograms/animal.day). The animals were treated for 8 days with different doses of onapristone (3.0, 10.0, and 30.0 mg/animal.day, sc). Uterine growth was not influenced by onapristone compared to that in OVX E2-substituted controls. However, morphological (light microscopy, transmission electron microscopy) and morphometric criteria indicated that there was a significant dose-dependent inhibition of the estrogen-induced gland formation within the endometrium and degenerative changes in glandular epithelial cells. By contrast, there were morphological signs of activation of the endometrial stroma (proliferation, increased capillarization, and vascularization, edema) above the level of E2-treated animals. A dose-dependent increase in the concentration of uterine cytosolic ER, nuclear ER, and ER mRNA (ER mRNA) was measured in uterine homogenates after onapristone treatment compared to values in OVX E2-substituted controls. Immunocytochemical analysis of ER in uterine sections suggests that the increase in ER after onapristone treatment took place predominantly in the myometrium and surface epithelium. To examine whether the observed interference was mediated via the progesterone receptor (PR), E2-substituted rabbits were treated, in a separate experiment, with onapristone (10.0 mg/animal.day, sc) and various doses of progesterone (1.0, 3.0, and 10.0 mg/animal.day, sc). Progesterone reversed all onapristone-induced changes, indicating that the observed effects were mediated via the PR. The data indicate that the antigestagen onapristone interacts with estrogen action in the absence of the natural PR ligand. The increase in ER and ER mRNA concentrations after onapristone treatment in OVX E2-treated animals suggests that this antigestagen abolished an inhibitory action of the unoccupied PR on ER biosynthesis.


Asunto(s)
Endometrio/crecimiento & desarrollo , Estradiol/farmacología , Antagonistas de Estrógenos/farmacología , Gonanos/farmacología , Progesterona/antagonistas & inhibidores , Receptores de Estrógenos/metabolismo , Útero/metabolismo , Animales , Núcleo Celular/metabolismo , Citosol/metabolismo , Endometrio/efectos de los fármacos , Endometrio/ultraestructura , Epitelio/ultraestructura , Femenino , Técnicas para Inmunoenzimas , Microscopía Electrónica , Tamaño de los Órganos , Ovariectomía , ARN Mensajero/metabolismo , Conejos , Receptores de Estrógenos/genética , Receptores de Progesterona/genética , Útero/efectos de los fármacos , Útero/crecimiento & desarrollo
9.
Clin Pharmacol Ther ; 57(4): 381-9, 1995 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-7712665

RESUMEN

OBJECTIVE: To investigate the influence of changes in liver blood flow on the pharmacokinetics and pharmacodynamics of single-chain unglycosylated urokinase-type plasminogen activator. METHODS: This open, randomized, crossover trial was carried out in the clinical research unit. Infusions of 37.5 mg saruplase and 90 mg indocyanine green were administered over 150 minutes to 10 healthy male volunteers. After 60 minutes the subjects consumed a standardized meal to increase liver blood flow or performed an exercise test (20 minutes) to decrease liver blood flow. Indocyanine green concentrations, total urokinase-type plasminogen activator (u-PA) antigen, two-chain u-PA activity, fibrinogen, total degradation products, alpha 2-antiplasmin, and factor XII-dependent fibrinolytic activity were measured. Blood flow was measured after food intake in a portal vein branch with Doppler echography. RESULTS: The weighted average indocyanine green concentration after exercise was increased by 29% compared with baseline (steady-state concentration) values (95% confidence intervals [CI]: +6%, +56%). After food, the concentration was 27% lower compared with baseline values (95% CI: -35%, -19%), and portal vein flow was increased by a maximum of 103% (95% CI: +71%, +136%). Average maximal concentrations of u-PA antigen after exercise were increased by 130 ng/ml compared with baseline concentrations (95% CI: +65, +195 ng/ml) and, unexpectedly, 156 ng/ml higher after food (95% CI: +59, +253 ng/ml). Although not significant, an increase in average u-PA antigen concentration compared with baseline values was detected after both exercise (7%) and food (13%). This tendency toward a larger effect after food compared with the effect after exercise was reflected by minor changes in the pharmacodynamics. CONCLUSIONS: u-PA plasma concentrations were increased by reduced liver blood flow induced by exercise. Food intake produced an unexpected increase in u-PA concentrations despite increases in liver blood flow.


Asunto(s)
Precursores Enzimáticos/farmacología , Ejercicio Físico/fisiología , Fibrinolíticos/farmacología , Alimentos , Circulación Hepática/fisiología , Activador de Plasminógeno de Tipo Uroquinasa/farmacología , Adulto , Precursores Enzimáticos/farmacocinética , Fibrinolíticos/farmacocinética , Humanos , Hígado/diagnóstico por imagen , Masculino , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/farmacología , Valores de Referencia , Ultrasonografía Doppler de Pulso , Activador de Plasminógeno de Tipo Uroquinasa/farmacocinética
10.
Gene ; 257(2): 177-85, 2000 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-11080584

RESUMEN

tRNA splicing endonuclease is essential for the correct removal of introns from precursor tRNA molecules of Archaea and Eucarya. The only well-characterized eucaryotic enzyme until now is the endonuclease from yeast (Saccharomyces cerevisiae). This protein has a heterotetrameric structure. Two of the four subunits, i.e. Sen34 and Sen44, contain the active sites for cleavage at the 3'- and 5'-splice sites, respectively. We have identified three novel genes from Arabidopsis thaliana, encoding putative subunits of tRNA splicing endonuclease. They are designated as AtSen1, AtSen2, and AtpsSen1. Both genes AtSen1 and AtSen2 seem to be functionally active, as deduced from corresponding cDNA sequences. Comparison of the amino acid sequences of the these two Arabidopsis proteins revealed 72% identity. However, AtpsSen1 is more similar to AtSen1, but is very likely a pseudogene, as concluded from extended stretches of deletions and the presence of in-frame stop codons. All putative proteins contain a conserved domain at their C-terminus common to counterparts from other organisms. Interestingly, they are more similar to the yeast catalytic subunit Sen44 than to Sen34. Southern analysis with various probes revealed that each gene is present as single copies in the nuclear genome. The evolutionary implications of these findings are discussed.


Asunto(s)
Arabidopsis/genética , Endorribonucleasas/genética , Secuencia de Aminoácidos , Arabidopsis/enzimología , Secuencia de Bases , Dominio Catalítico , Clonación Molecular , ADN Complementario/química , ADN Complementario/genética , ADN de Plantas/química , ADN de Plantas/genética , Endorribonucleasas/química , Dosificación de Gen , Orden Génico , Genes de Plantas/genética , Datos de Secuencia Molecular , Filogenia , Subunidades de Proteína , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido
11.
Gene ; 156(1): 129-32, 1995 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-7737506

RESUMEN

Six of 13 cloned members of the human tRNA(Val) gene family code for tRNA(Val) pseudogenes, of which all but one are transcribed efficiently in HeLa cell extracts. Due to single or multiple mismatches in stem regions, the corresponding pre-tRNAs are resistant against the action of human 5'- and 3'-processing enzymes and are thus prevented from being converted to mature tRNAs. Surprisingly, all of them are accurately and efficiently processed to mature-sized tRNA in yeast nuclear extract. This is in agreement with corresponding studies of plant pre-tRNAs which are not processed in wheat germ extract but are rapidly processed in yeast extract. These observations imply that the yeast pre-tRNA 5'- and 3'-maturases do not monitor the three-dimensional structure of their substrates as stringently as mammalian and plant enzymes, possibly because tRNA pseudogenes do not occur in yeast.


Asunto(s)
Seudogenes/genética , Precursores del ARN/metabolismo , Procesamiento Postranscripcional del ARN , ARN de Transferencia de Valina/genética , Saccharomyces cerevisiae/metabolismo , Extractos Celulares , Núcleo Celular/metabolismo , Células HeLa , Humanos , Conformación de Ácido Nucleico , Plantas/enzimología , Plantas/genética , Plantas/metabolismo , Mutación Puntual/fisiología , Precursores del ARN/genética , ARN de Transferencia de Valina/química , ARN de Transferencia de Valina/metabolismo , Saccharomyces cerevisiae/genética , Especificidad de la Especie , Transcripción Genética/fisiología
12.
Gene ; 262(1-2): 161-8, 2001 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-11179680

RESUMEN

Amplification of macronuclear DNA of the ciliate Euplotes octocarinatus revealed the presence of two genes encoding putative polypeptide release factors (RFs) of the codon specific class-I type. They are named eRF1a and eRF1b, respectively. cDNA amplification revealed that both eRF1 genes are expressed. Determination of their copy numbers showed that they are similarly amplified to a level of about 27,000. The deduced protein sequences of the two genes are 57 and 58% identical with human eRF1 and 79% identical to each other. The gene encoding eRF1b possesses three in-frame UGA codons. This codon is known to encode cysteine in Euplotes; only UAA and UAG are used as stop codons in this organism. The primary structure of the two release factors is analyzed and compared with the primary structure of other eukaryotic release factors including the one of Tetrahymena thermophila which uses only UGA as a stop codon. eRF1a and eRF1b of Euplotes as well as eRF1 of Tetrahymena differ from human eRF1 and other class-I release factors of eukaryotes in a domain recently proposed to be responsible for codon recognition. Based on the changes which we observe in this region and the differential use of the stop codons in these two ciliates we predict the amino acids participating in stop codon recognition in eRF1 release factors.


Asunto(s)
Euplotes/genética , Factores de Terminación de Péptidos/genética , Secuencia de Aminoácidos , Animales , Clonación Molecular , Codón de Terminación , Dosificación de Gen , Datos de Secuencia Molecular , Proteínas Nucleares/genética , Homología de Secuencia de Aminoácido
13.
FEBS Lett ; 384(3): 222-6, 1996 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-8617358

RESUMEN

Southern analysis of Triticum DNA has revealed that nuclear tRNATyr genes are dispersed at a minimum of 16 loci in the genome. We have isolated six independent tRNATyr genes from a Triticum aestivum library in addition to three known members of the Triticum tRNATyr family. Four of the sequenced tRNATyr genes code for Triticum tRNA Tyr and two code for tRNA2Tyr. Three genes encode tRNAsTyr which carry one or two nucleotide substitutions as compared to the conventional genes. The nine Triticum tRNATyr genes possess highly conserved intron sequences ranging in size from 12 to 14 nucleotides. A common secondary intron structure with the 5' and 3' splice site loops separated by five base pairs can be formed by all pre-tRNAs Tyr which are efficiently spliced in the homologous wheat germ extract.


Asunto(s)
Genoma de Planta , ARN de Transferencia de Tirosina/química , ARN de Transferencia de Tirosina/genética , Triticum/genética , Secuencia de Bases , Extractos Celulares , ADN de Plantas/química , Exones , Células HeLa , Humanos , Datos de Secuencia Molecular , Familia de Multigenes , Extractos Vegetales/química , Precursores del ARN , Procesamiento Postranscripcional del ARN , Empalme del ARN , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Transcripción Genética
14.
FEBS Lett ; 417(2): 213-8, 1997 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-9395298

RESUMEN

We have previously isolated numerous intron-containing nuclear tRNA(Tyr) genes derived from either monocotyledonous (Triticum) or dicotyledonous (Arabidopsis, Nicotiana) plants by screening the corresponding genomic phage libraries with a synthetic tRNA(Tyr)-specific oligonucleotide. Here we have characterized additional tRNA(Tyr) genes from phylogenetically divergent plant species representing red algae (Champia), brown algae (Cystophyllum), green algae (Ulva), stonewort (Chara), liverwort (Marchantia), moss (Polytrichum), fern (Rumohra) and gymnosperms (Ginkgo) using amplification of the coding sequences from the corresponding genomic DNAs by polymerase chain reaction (PCR). All novel tRNA(Tyr) genes contain intervening sequences of variable sequence and length ranging in size from 11 to 21 bp. However, two features are conserved in all plant pre-tRNA(Tyr) introns: they possess a uridine and less frequently an adenosine at the 5' boundary and can adopt similar intron secondary structures in which an extended anticodon helix of 4-5 bp is formed by base-pairing between nucleotides of the intron and the anticodon loop. In order to elucidate the potential role of the highly conserved uridine at the first intron position, we have replaced it by all other nucleosides in an Arabidopsis pre-tRNA(Tyr) and have studied in wheat germ extract its effect on splicing and on conversion of U to psi in the GpsiA anticodon. Furthermore, we discuss the putative acquisition of tRNA(Tyr) introns at an early step of evolution after the separation of Archaea and Eucarya.


Asunto(s)
Genes de Plantas , Intrones , ARN de Transferencia de Tirosina/genética , Anticodón , Secuencia de Bases , Núcleo Celular , Endonucleasas/metabolismo , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Filogenia , Reacción en Cadena de la Polimerasa , Seudouridina/genética , Homología de Secuencia de Ácido Nucleico , Relación Estructura-Actividad
15.
FEBS Lett ; 457(2): 193-9, 1999 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-10471777

RESUMEN

It has been reported recently that naturally occurring catalytic RNAs like hammerhead and hairpin ribozyme do not require metal ions for efficient catalysis. It seems that the folded tertiary structure of the RNA contributes more to the catalytic function than was initially recognized. We found that a highly specific self-cleavage reaction can occur within a small bulge loop of four nucleotides in a mini-substrate derived from Arabidopsis thaliana intron-containing pre-tRNA(Tyr) in the absence of metal ions. NH(4)(+) cations and non-ionic or zwitter-ionic detergents at or above their critical micelle concentration are sufficient to catalyze this reaction. The dependence on micelles for the reaction leads to the assumption that physical properties, i.e. the hydrophobic interior of a micelle, are essential for this self-cleavage reaction. We suggest that NH(4)(+)-ions play a crucial role for the entry of the negatively charged RNA into the hydrophobic interior of a detergent micelle. A change of the pattern of hydration or hydrogen bonds caused by the hydrophobic surrounding enhances the reaction by a factor of 100. These findings suggest that highly structured RNAs may shift pK(a) values towards neutrality via the local environment and thereby enhance their ability to perform general acid-base catalysis without the participation of metal ions.


Asunto(s)
ARN Catalítico/metabolismo , ARN de Planta/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Secuencia de Bases , Detergentes/farmacología , Magnesio/metabolismo , Micelas , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Compuestos de Amonio Cuaternario/metabolismo , Precursores del ARN/metabolismo , ARN Catalítico/efectos de los fármacos , ARN de Transferencia de Tirosina/metabolismo , Espermina/metabolismo
16.
Thromb Haemost ; 70(2): 320-5, 1993 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-8236142

RESUMEN

Pharmacokinetics of two doses of the recombinant single-chain urokinase-type plasminogen activator (r-scu-PA) saruplase (40 and 20 mg) and its effect on fibrinolytic and haemostatic parameters were studied in six healthy male subjects using a randomized, double-blind, placebo-controlled, cross-over study. Special precautions were taken to prevent artefactual in vitro effects on fibrinolytic activity. The clearance of saruplase ranged from 310 to 862 ml/min and the apparent volume of distribution of the central compartment was about 8 1. Both doses of saruplase caused alpha 2-antiplasmin consumption, indicating some systemic fibrinolytic activation. However, the 20 mg dose caused no detectable fibrinogen breakdown and only a small increase in total fibrin/fibrinogen degradation products (TDP) (from 0.16 microgram/ml [range 0.14 to 0.19] to 0.78 microgram/ml [range 0.56 to 1.26]), while the 40 mg dose produce a fibrinogen breakdown to an average value of 44% (range 19 to 60%) and TDP increased from 0.12 microgram/ml (range 0.11-0.12) to 2.29 micrograms/ml (range 0.45 to 5.55). The breakdown of fibrinogen was related to the quantity of saruplase converted to active two-chain u-PA (tcu-PA) in vivo (6 to 22% conversion). There were no important effects of saruplase on overall blood coagulation (activated partial thromboplastin time) and platelet function (collagen induced platelet aggregation, urinary [2,3-dinor]-thromboxane B2 excretion and plasminogen activator inhibitor 1 [PAI-1] release from platelets). Saruplase is cleared rapidly from the plasma and a variable amount is converted to tcu-PA. This two-chain form of u-PA probably causes the dose-dependent systemic fibrinolytic activation.


Asunto(s)
Fibrinólisis/efectos de los fármacos , Hemostasis/efectos de los fármacos , Activador de Plasminógeno de Tipo Uroquinasa/farmacología , Adulto , Secuencia de Aminoácidos , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Humanos , Masculino , Tasa de Depuración Metabólica , Datos de Secuencia Molecular , Tiempo de Tromboplastina Parcial , Inhibidor 1 de Activador Plasminogénico/análisis , Pruebas de Función Plaquetaria , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/farmacología , Activador de Plasminógeno de Tipo Uroquinasa/farmacocinética
17.
Thromb Haemost ; 72(5): 740-4, 1994 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7534946

RESUMEN

We examined in patients with acute myocardial infarction (AMI) the pharmacokinetics of saruplase, an unglycosylated, single chain, urokinase-type plasminogen activator (rscu-PA) by measuring urokinase-type plasminogen activator (u-PA) antigen and total u-PA activity, its conversion to active two-chain urokinase-type plasminogen activator (tcu-PA) and evaluated its effect on haemostatic parameters. Twelve patients were studied during and after administration of 20 mg bolus plus 60 mg continuous 1 h i.v. infusion of saruplase. For u-PA antigen and total u-PA activity (expressed as protein equivalents), where 234 U corresponds to 1 microgram, respectively, steady state plasma concentrations were 2.75 +/- 8.3 and 2.50 +/- 7.0 micrograms/ml (mean +/- standard deviation) and were reached within 20 min, t1/2 lambda 1 was 9.1 +/- 1.8 and 7.8 +/- 1.3 min, t1/2 lambda 2 1.2 +/- 0.2 and 1.9 +/- 0.5 h, and the total clearance was 393 +/- 110 and 427 +/- 113 ml/min. Inactivation of saruplase in plasma was negligible. After 15 min, tcu-PA was detected in plasma. From the ratio of the areas under the curve of tcu-PA and total u-PA activities it was calculated that 28 +/- 9.3% of the saruplase dose is converted into active tcu-PA. Systemic plasminaemia occurs as shown by a decrease in alpha 2-antiplasmin and fibrinogen and an increase in fibrinogen degradation products. Thrombin-antithrombin complex formation indicated activation of the clotting system. Saruplase is eliminated rapidly from plasma in AMI patients.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Fibrinolíticos/farmacología , Hemostasis/efectos de los fármacos , Infarto del Miocardio/tratamiento farmacológico , Activador de Plasminógeno de Tipo Uroquinasa/efectos de los fármacos , Activador de Plasminógeno de Tipo Uroquinasa/farmacología , Adulto , Anciano , Antitrombina III/metabolismo , Productos de Degradación de Fibrina-Fibrinógeno/metabolismo , Fibrinógeno/metabolismo , Fibrinolisina/metabolismo , Fibrinolíticos/farmacocinética , Glicosilación , Humanos , Persona de Mediana Edad , Infarto del Miocardio/sangre , Péptido Hidrolasas/metabolismo , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/farmacología , Activador de Plasminógeno de Tipo Uroquinasa/farmacocinética , alfa 2-Antiplasmina/metabolismo
18.
Thromb Haemost ; 78(3): 1015-20, 1997 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9308746

RESUMEN

BACKGROUND: The recombinant unglycosylated single chain urokinase-type plasminogen activator saruplase is cleared for a large part by the liver. A large interindividual variation in saruplase concentration is found in acute myocardial infarction (AMI) patients. The variable cardiac performance after an infarct may induce differences in liver blood flow that could explain the concentration diversity. This study was performed to investigate the relation between hepatic blood flow and the pharmacokinetic and pharmacodynamic properties of saruplase. METHODS AND RESULTS: Thirteen AMI patients were enrolled in this open label study. Patients received a bolus injection of 20 mg saruplase followed by a one-hour infusion of 60 mg saruplase. Concurrently 36 mg intravenous indocyanine green (ICG) was given over 1 h to measure hepatic blood flow. Blood samples were taken at regular time intervals to measure plasma levels of urokinase-type plasminogen activator (u-PA) antigen and activity, the two-chain form (tcu-PA) activity, indocyanine green, fibrinogen, fibrin and fibrin degradation products, alpha2-antiplasmin and thrombin antithrombin III complex. A correlation was seen between the clearance of ICG and both those of u-PA antigen (r = 0.62; p <0.05) and u-PA activity (r = 0.57; p <0.05). A negative correlation was seen between the area under the curve of tcu-PA activity and the areas under the effect curves of both fibrinogen and alpha2-antiplasmin (r = -0.84; p <0.01 and r = -0.65; p <0.05). CONCLUSIONS: Liver blood flow is an important determinant of the clearance of u-PA antigen and activity and reduction of flow in patients with heart failure will lead to an increase in plasma concentrations. High plasma concentrations of tcu-PA activity lead to increased systemic fibrinogenolysis. These results may be used to optimize saruplase treatment in patients with impaired cardiac function or after co-medication with drugs that affect liver blood flow.


Asunto(s)
Fibrinolíticos/uso terapéutico , Circulación Hepática , Hígado/irrigación sanguínea , Infarto del Miocardio/tratamiento farmacológico , Activador de Plasminógeno de Tipo Uroquinasa/farmacocinética , Anciano , Femenino , Fibrinólisis , Humanos , Verde de Indocianina/farmacocinética , Masculino , Persona de Mediana Edad , Infarto del Miocardio/metabolismo , Proteínas Recombinantes/farmacocinética , Flujo Sanguíneo Regional , Activador de Plasminógeno de Tipo Uroquinasa/sangre
19.
Placenta ; 24(10): 929-40, 2003 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-14580375

RESUMEN

During the first trimester of pregnancy extravillous trophoblast cells (EVT) invade the maternal decidua. Invasion normally is reduced from the second trimester onwards and stops in the inner third of the myometrium. By contrast, in extrauterine tubal pregnancy, trophoblast invasion may even penetrate the tubal wall, which ultimately leads to the rupture of the fallopian tube. Induction of apoptosis of EVT cells, by maternal immune competent cells, may be an important mechanism to limit EVT invasion in uterine pregnancy. Tissue specimens from first and second trimester uterine pregnancy and first trimester tubal pregnancy were analyzed for apoptosis by TUNEL- and M30-staining. By immunohistochemical double labelling, maternal leukocyte subtypes were co-localized to apoptotic cells and in this context, the number of CD56(+)NK cells was analyzed. Our data show that apoptosis is confined to the decidua basalis. Most apoptotic cells are single cytokeratin-positive epithelial cells residing in the stromal compartment. Consequently these cells can only be EVT cells. Maternal leukocytes are not apoptotic. They are located in close contact to apoptotic cells. The number of apoptotic cells in the second trimester (1.8+/-0.7 per cent) is reduced compared to first trimester (5.6+/-0.7 per cent) of uterine pregnancy. In parallel, the number of NK cells declines from first (24.4+/-2.9) to second (12.4+/-1.8) trimester. Furthermore, apoptosis is significantly reduced in ectopic (0.9+/-0.3 per cent) compared to eutopic first trimester pregnancies. Consequently, we suggest that in first trimester uterine pregnancy, induction of EVT cell apoptosis by the maternal immune system is one mechanism to limit EVT invasion. During the second trimester, in parallel to declining numbers of NK cells, the mechanism changes. However, in tubal pregnancy due to differing immunological microenvironments at the ectopic implantation site, apoptosis induction fails, which deleteriously may result in uncontrolled invasion and penetration of the tubal wall.


Asunto(s)
Apoptosis , Implantación del Embrión , Embarazo/inmunología , Trofoblastos/citología , Útero/citología , Antígeno CD56/inmunología , Decidua/citología , Femenino , Humanos , Células Asesinas Naturales/inmunología , Antígenos Comunes de Leucocito/inmunología , Leucocitos/inmunología , Macrófagos/inmunología , Primer Trimestre del Embarazo , Embarazo Tubario/patología , Trofoblastos/patología , Trofoblastos/fisiología , Útero/metabolismo , Útero/patología
20.
Mol Cell Endocrinol ; 25(2): 183-91, 1982 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-7056434

RESUMEN

In an attempt to understand the mechanism of the antiprogestational action of estrogens during early pseudopregnancy we determined the cytosolic and nuclear concentrations of progesterone receptors in the endometrium of rabbits treated with hCG followed by various combinations of estradiol and progesterone. The progestational response of the endometrium was followed by quantitation of the uteroglobin content in the uterine lumen. In rabbits treated with hCG alone there was a clear progestational response (40% relative uteroglobin content), but only 16% of the progesterone receptors were located in the nucleus. After additional treatment with progesterone the progestational response remained high (45% relative uteroglobin content), the total cellular content of progesterone receptor increased, and 5% of the complexes were found in the nucleus. These findings suggest that a consumption of nuclear progesterone receptor is required for progestational action. Treatment of pseudopregnant rabbits with estradiol resulted in a marked increase not only of the total cellular progesterone receptor but also of the percentage of it located in the nucleus (35%). Concomitantly, the progestational response was markedly inhibited (5% relative uteroglobin content). These results confirm the relevance of nuclear consumption of progesterone receptor for progestational action, and suggest that some antiprogestational effects of estrogens may be due to their interference with the mechanism of progesterone receptor processing.


Asunto(s)
Endometrio/análisis , Receptores de Progesterona/análisis , Animales , Núcleo Celular/análisis , Citosol/análisis , Estradiol/sangre , Estradiol/farmacología , Femenino , Progesterona/sangre , Progesterona/farmacología , Seudoembarazo/metabolismo , Conejos , Receptores de Progesterona/efectos de los fármacos , Uteroglobina/biosíntesis
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