Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
1.
Knee Surg Sports Traumatol Arthrosc ; 29(2): 540-545, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32274549

RESUMEN

PURPOSE: The effect of a distal femur varization osteotomy on patellofemoral biomechanics in genu valgum is unknown. The purpose of this study was to quantify the influence of frontal leg axis correction on the Q-angle with a novel three-dimensional (3-D) measurement method. METHODS: 3-D surface models of ten lower extremities were generated using patient computed tomography (CT) data. The preoperative 3-D Q-angle was measured using a novel defined and validated 3-D measurement method. Biplanar supracondylar osteotomies were simulated with different degrees of varus correction (from 1° to 15°) in one-degree steps beginning from the preoperative valgus deformity, resulting in a total of 150 simulations. Additionally, mechanical leg axis and 3-D Q-angle measurements were performed on 3-D surface models of the postoperative CT scans of the same individuals. Further, pre- and postoperative TT-TG distance was measured. RESULTS: Mean preoperative Q-angle was 15.8 ± 3.9° (range 10°-21.4°) with a mean preoperative mechanical leg axis of 6.5° ± 2.4 valgus (range 3.8°-11.6° valgus). The Q-angle changed linearly 0.9 ± 0° per 1° of varization. No difference was detected between simulated 3-D Q-angles and effectively corrected postoperative values (n.s.). TT-TG distance changed irregularly and minimally, and with no correlation to the degree of varization. CONCLUSION: Distal femur varization osteotomy has a linear effect on the Q-angle with a change of 1° per 1° of varization. The difference in TT-TG distance was mainly due to an unintentional rotational component implemented during surgery.


Asunto(s)
Fémur/diagnóstico por imagen , Fémur/cirugía , Genu Valgum/cirugía , Osteotomía/métodos , Adulto , Fenómenos Biomecánicos , Simulación por Computador , Fémur/fisiopatología , Genu Valgum/diagnóstico por imagen , Genu Valgum/fisiopatología , Historia del Siglo XVI , Humanos , Imagenología Tridimensional , Extremidad Inferior/fisiopatología , Extremidad Inferior/cirugía , Persona de Mediana Edad , Periodo Posoperatorio , Tomografía Computarizada por Rayos X
2.
Knee Surg Sports Traumatol Arthrosc ; 29(6): 1760-1768, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32785758

RESUMEN

PURPOSE: The role of increased femoral antetorsion (femAT) as a contributor to patellofemoral (PF) osteoarthritis (OA) is unknown. The purpose of this study was to investigate whether increased femAT was associated with advanced cartilage degeneration in the lateral PF joint. METHODS: Patients who underwent complete radiographic workup for surgical intervention due to OA in any knee joint compartment were included. Cartilage morphology according to the International Cartilage Repair Society (ICRS) cartilage lesion classification system in the PF joint, femoral and tibial torsion, frontal leg axis, and tibial tuberosity-trochlear groove (TT-TG) distance were assessed. Increased femAT was defined as > 20° according to previous reports. RESULTS: A total of 144 patients were included. Ninety-seven patients had a femAT of < 20° and 45 of > 20°. A significant odds ratio (OR) was found for lateral retropatellar (OR 3.5; p = 0.02) ICRS grade 3 and 4 cartilage degeneration and increased femAT ≥ 20°. In the medial PF compartment, increased femAT had an inverse effect (OR 0.16; p = 0.01). No significant ORs were found for TT-TG distance, tibial torsion, or leg axis. The lateral retropatellar ICRS grade showed a linear correlation to increased femAT values. In valgus knees, isolated lateral PF OA had an even more pronounced correlation to increased femAT (p = 0.004). CONCLUSION: Increased femAT showed higher grades of lateral retropatellar cartilage degeneration, which was even more pronounced in valgus knees. LEVEL OF EVIDENCE: Cohort study: Level III.


Asunto(s)
Enfermedades de los Cartílagos/epidemiología , Fémur/patología , Genu Valgum/epidemiología , Osteoartritis de la Rodilla/epidemiología , Articulación Patelofemoral/patología , Adulto , Anciano , Anciano de 80 o más Años , Cartílago/patología , Estudios de Cohortes , Femenino , Humanos , Articulación de la Rodilla/patología , Modelos Logísticos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Tibia/patología
3.
Knee Surg Sports Traumatol Arthrosc ; 29(10): 3254-3261, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32607816

RESUMEN

PURPOSE: The purpose of the present study was to compare total (TKA) and unicondylar (UKA) knee arthroplasty for spontaneous osteonecrosis of the knee (SONK), and to investigate potential correlations to radiographic parameters. METHODS: All consecutive patients with a magnetic resonance imaging (MRI) proven SONK treated with either TKA or UKA between 2002 and 2018 were analysed. The primary outcomes were postoperative complications and failure rates. Functional assessment included Knee Society Score (KSS), WOMAC Score, and range of motion. A novel three-dimensional measurement method was established to determine the size of the osteonecrotic lesion. All outcome parameters were correlated to the size of the necrotic lesion using Spearman's rank correlation. RESULTS: The two treatment groups (34 TKAs, 37 UKAs) did not differ regarding age, body mass index, and ratio of the volume of the necrotic lesion to the volume of the femoral condyle (n.s.). At a mean follow-up of 6.6 years, patients with UKA had better functional outcomes compared to patients with a TKA (WOMAC Score 1.0 vs. 1.6, p = 0.04; KSS pain 86 vs. 83, n.s), with a similar complication rate. No correlation was found between necrotic lesion size and failure rate (n.s.). CONCLUSION: UKA is a valuable treatment option for SONK leading to good functional results and a low failure rate. In case of a surgeon's concern regarding implant anchorage, TKA represents an equivalent solution. The MR-tomographic size of the osteonecrotic lesions seems to have no influence on the results. LEVEL OF EVIDENCE: III.


Asunto(s)
Artroplastia de Reemplazo de Rodilla , Osteoartritis de la Rodilla , Osteonecrosis , Humanos , Articulación de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/cirugía , Osteoartritis de la Rodilla/cirugía , Osteonecrosis/cirugía , Resultado del Tratamiento
4.
Eur J Neurosci ; 44(6): 2369-74, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27422569

RESUMEN

Although a direct relationship between numerical allocation and spatial attention has been proposed, recent research suggests that these processes are not directly coupled. In keeping with this, spatial attention shifts induced either via visual or vestibular motion can modulate numerical allocation in some circumstances but not in others. In addition to shifting spatial attention, visual or vestibular motion paradigms also (i) elicit compensatory eye movements which themselves can influence numerical processing and (ii) alter the perceptual state of 'self', inducing changes in bodily self-consciousness impacting upon cognitive mechanisms. Thus, the precise mechanism by which motion modulates numerical allocation remains unknown. We sought to investigate the influence that different perceptual experiences of motion have upon numerical magnitude allocation while controlling for both eye movements and task-related effects. We first used optokinetic visual motion stimulation (OKS) to elicit the perceptual experience of either 'visual world' or 'self'-motion during which eye movements were identical. In a second experiment, we used a vestibular protocol examining the effects of perceived and subliminal angular rotations in darkness, which also provoked identical eye movements. We observed that during the perceptual experience of 'visual world' motion, rightward OKS-biased judgments towards smaller numbers, whereas leftward OKS-biased judgments towards larger numbers. During the perceptual experience of 'self-motion', judgments were biased towards larger numbers irrespective of the OKS direction. Contrastingly, vestibular motion perception was found not to modulate numerical magnitude allocation, nor was there any differential modulation when comparing 'perceived' vs. 'subliminal' rotations. We provide a novel demonstration that numerical magnitude allocation can be differentially modulated by the perceptual state of self during visual but not vestibular mediated motion.


Asunto(s)
Atención/fisiología , Movimientos Oculares/fisiología , Percepción de Movimiento/fisiología , Movimiento (Física) , Percepción Espacial/fisiología , Femenino , Humanos , Masculino , Modelos Neurológicos , Orientación/fisiología , Estimulación Luminosa/métodos , Desempeño Psicomotor/fisiología , Vestíbulo del Laberinto/fisiología , Adulto Joven
5.
Biochim Biophys Acta ; 1207(1): 102-8, 1994 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-8043598

RESUMEN

The membrane-bound enzyme 3 beta-hydroxysteroid dehydrogenase delta 5-4 isomerase (3 beta-HSD) catalyzes the formation of delta 4-3-ketosteroids from delta 5-3 beta-hydroxysteroids in placental, adrenal, testicular and ovarian tissues. In the present study was investigated the transverse-plane topography of 3 beta-HSD within the human placental microsome membranes employing immune-replica analysis in combination with surface specific proteolysis. The crucial domains of the enzyme for the dehydrogenase and isomerase reactions are inactivated by proteinase treatments under conditions where latency of hexose-6-phosphate dehydrogenase was 95%. The data indicate that these crucial domains face the cytosolic side of the endoplasmic reticulum membrane. Incubation of the intact microsomes with trypsin produces several immune reactive fragments ranging from 29 to 11 kDa in addition to 42 kDa native enzyme, one of them being shielded by the membrane structure and/or by other intrinsic and peripheral membrane proteins. Carboxypeptidase Y degraded the C terminus of the 42 kDa native 3 beta-HSD in intact and detergent-disrupted microsomes, preserving partially a fragment of 31 kDa. The results from the carboxypeptidase Y digestion indicate that the carboxy terminal end of the 3 beta-HSD enzyme is located on the cytoplasmic surface of the endoplasmic reticulum and that only a small fragment of approx. 11 kDa could be removed easily without affecting the enzyme activity. From these data and the predicted hydropathy analysis from the literature, we tried to assign a transmembrane arrangement to the human placental 3 beta-HSD. Our results support a topology model in which practically all the structural 3 beta-HSD enzyme is exposed to the cytoplasmic side of the membrane with one NH2-terminal-anchoring segment and all the 3 beta-HSD enzyme activity facing to the cytoplasmic side within the 31 kDa NH2-terminal peptide.


Asunto(s)
Complejos Multienzimáticos/química , Placenta/enzimología , Progesterona Reductasa/química , Esteroide Isomerasas/química , Carboxipeptidasas , Citoplasma/enzimología , Endopeptidasa K , Humanos , Immunoblotting , Membranas Intracelulares/enzimología , Microsomas/enzimología , Estructura Molecular , Serina Endopeptidasas , Tripsina
6.
J Clin Endocrinol Metab ; 76(1): 108-11, 1993 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8421073

RESUMEN

The complete hydatidiform mole (CHM) is characterized by the presence of aberrant placenta, with hyperplasia of cyto- and syncytiotrophoblasts and the absence of maternal genetic information. Steroidogenesis in this condition is, thus, of special interest. In this study we investigated the kinetic parameters of aromatase in microsomes from CHM compared with those in normal early placenta (NEP). The enzyme activity was determined by measuring the conversion of [3H] testosterone to [3H]estradiol plus [3H]estrone. The Km value for testosterone was 33 nmol/L in CHM and 17 nmol/L in NEP of similar gestational ages. Aminoglutethimide, a nonsteroidal inhibitor, decreased in a dose-dependent manner and with the same potency the aromatization of testosterone in both tissues (ID50, 2 vs. 1 mumol/L in CHM and NEP, respectively). These results suggest that the enzymes from the two sources are kinetically similar. However, the enzyme efficiency, expressed as the maximum velocity/Km ratio, was 17-fold lower in CHM than in NEP tissue (1.22/33 vs. 10.68/17 min/mg.mL). These findings suggest that in molar pregnancy the decreased capacity of trophoblast tissue for the formation of estrogen could increase the testosterone concentration inside the molar vesicle, which, in turn, as we previously reported, inhibits progesterone formation. All of these data could provide an explanation for the low circulating level of progesterone, which may directly or indirectly affect the spontaneous expulsion of this aberrant tissue in the second trimester of pregnancy.


Asunto(s)
Aromatasa/metabolismo , Mola Hidatiforme/enzimología , Microsomas/enzimología , Placenta/enzimología , Neoplasias Uterinas/enzimología , Aborto Terapéutico , Aminoglutetimida/farmacología , Femenino , Humanos , Cinética , Embarazo , Valores de Referencia , Especificidad por Sustrato
7.
Gene ; 105(1): 43-9, 1991 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-1657714

RESUMEN

The structural gene (hsd) of the Pseudomonas testosteroni encoding the 17 beta-hydroxysteroid dehydrogenase has been cloned using the cosmid vector pVK102. Escherichia coli carrying recombinant clones of hsd, isolated by immunological screening, were able to express the biologically active enzyme, as measured by the conversion of testosterone into androstenedione. Subcloning experiments, restriction and deletion analysis, and site-directed insertion mutagenesis showed that the hsd gene is located within a 1.3-kb HindIII-PstI restriction fragment. A 26.5-kDa protein encoded by a recombinant plasmid containing this Ps. testosteroni DNA restriction fragment was detected by SDS-PAGE analysis of in vitro [35S]methionine-labeled polypeptides.


Asunto(s)
17-Hidroxiesteroide Deshidrogenasas/genética , Proteínas Bacterianas/genética , Pseudomonas/enzimología , Clonación Molecular , Cósmidos/genética , Electroforesis en Gel de Poliacrilamida , Escherichia coli/metabolismo , Expresión Génica/fisiología , Biblioteca Genómica , Immunoblotting , Mutagénesis Sitio-Dirigida , Pseudomonas/genética , Proteínas Recombinantes/biosíntesis , Mapeo Restrictivo , Testosterona/metabolismo
8.
FEBS Lett ; 409(3): 396-400, 1997 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-9224697

RESUMEN

A group of eleven sesquiterpene lactones isolated from different Asteraceae species from north-western Argentina were investigated for their inhibitory action on the estrogen biosynthesis. Seven of them, of different skeleton types, were found to inhibit the aromatase enzyme activity in human placental microsomes, showing IC50 values ranging from 7 to 110 microM. The most active were the guaianolides 10-epi-8-deoxycumambrin B (compound 1), dehydroleucodin (compound 2) and ludartin (compound 3). These compounds were competitive inhibitors with an apparent Ki = 4 microM, Ki = 21 microM and Ki = 23 microM, respectively. Compounds 1 and 2 acted as type II ligands to the heme iron present in the active site of aromatase cytochrome P450 (P450arom). Besides, all of them failed to affect the cholesterol side-chain cleavage enzyme activity on human placental mitochondrias. This is the first report on the aromatase inhibitory activity of this group of natural compounds.


Asunto(s)
Inhibidores de la Aromatasa , Lactonas/farmacología , Sesquiterpenos/farmacología , Antiulcerosos/farmacología , Enzima de Desdoblamiento de la Cadena Lateral del Colesterol/antagonistas & inhibidores , Relación Dosis-Respuesta a Droga , Humanos , Cinética , Lactonas/química , Microsomas/efectos de los fármacos , Microsomas/enzimología , Proteínas Gestacionales/antagonistas & inhibidores , Sesquiterpenos/química , Relación Estructura-Actividad
9.
Placenta ; 22(2-3): 220-6, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11170827

RESUMEN

To assess the molecular basis of phenotypic alterations present in the gestational trophoblastic diseases (GTDs) and to identify genes whose expression is specifically associated with these placental proliferative disorders we performed differential display (DD) techniques. This strategy resulted in the isolation of four mitochondrial transcripts downregulated in benign, as well as in malignant, trophoblastic diseases encoding the cytochrome oxidase subunit I (COX I), the ATPase subunit 6, the 12S ribosomal RNA (12S rRNA) and the transfer RNA for phenylalanine (tRNA(Phe)). This expression pattern was confirmed by Northern blot in normal early placenta (NEP), complete hydatidiform mole (CHM), persistent gestational trophoblastic disease (PGTD) and the human choriocarcinoma derived cell line JEG-3. Quantification of mitochondrial DNA by dot blot indicated that these changes in expression were not associated with a significant alteration in the number of mitochondrial genome. In addition, a reduction in the mitochondrial transcription factor A (mtTFA) mRNA level was observed in benign as well as in malignant trophoblastic diseases in correlation with the decrease in the mitochondrial transcript levels. Furthermore, Western blot analysis for COX-I showed a close parallelism with the expression level of the cognate RNA. Taken together, these data demonstrate that a significant change in mitochondrial transcription is associated with the phenotypic alteration present in GTDs.


Asunto(s)
Coriocarcinoma/genética , ADN Mitocondrial/genética , Expresión Génica , Mola Hidatiforme/genética , Prostaglandina-Endoperóxido Sintasas , Neoplasias Trofoblásticas/genética , Neoplasias Uterinas/genética , Adenosina Trifosfatasas/genética , Secuencia de Bases , Northern Blotting , Western Blotting , Clonación Molecular , ADN Mitocondrial/química , Complejo IV de Transporte de Electrones/genética , Femenino , Humanos , Isoenzimas , Proteínas de la Membrana , Datos de Secuencia Molecular , Embarazo , ARN Mensajero/análisis , ARN de Transferencia de Fenilalanina/genética , Análisis de Secuencia de ADN , Homología de Secuencia , Células Tumorales Cultivadas
10.
Int J Oncol ; 19(6): 1161-7, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11713585

RESUMEN

Gestational trophoblastic diseases, like the complete hydatidiform mole (CHM), are a group of human interrelated neoplasms whose etiology and progression is poorly understood at the molecular level. We have previously reported the cloning and expression of a new tumor necrosis factor receptor (TNF-R) related transcript, named CHMS-1 that encodes a potential death domain. Here we show that ectopic expression of the putative CHMS-1 death domain specifically induced apoptosis in a dose-dependent manner, in trophoblastic (JEG-3) and non-trophoblastic (COS-7) cells. We also investigated the expression of apoptosis-related molecules such as Bcl-2 and p53 and demonstrated that Bcl-2 is repressed in CHM while p53 is overexpressed in CHM compared with persistent gestational trophoblastic tumors. Altogether, these data indicate that the CHMS-1 death domain is able to trigger apoptosis, thus suggesting that this new entity might be an important inducer of molar regression mechanisms in women.


Asunto(s)
Apoptosis , Proteínas de Neoplasias/metabolismo , Receptores del Factor de Necrosis Tumoral/metabolismo , Trofoblastos/metabolismo , Animales , Northern Blotting , Femenino , Citometría de Flujo , Expresión Génica , Proteínas Fluorescentes Verdes , Humanos , Técnicas para Inmunoenzimas , Proteínas Luminiscentes/metabolismo , Proteínas de Neoplasias/genética , Embarazo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , ARN Mensajero/metabolismo , Receptores del Factor de Necrosis Tumoral/genética , Proteínas Recombinantes de Fusión/metabolismo , Transfección , Trofoblastos/patología , Células Tumorales Cultivadas/metabolismo , Células Tumorales Cultivadas/patología , Proteína p53 Supresora de Tumor/metabolismo
11.
Steroids ; 41(4): 467-74, 1983 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-6658884

RESUMEN

The effect of different doses of estradiol-17 beta (E2) on the metabolic pregnenolone to progesterone pathway in fragments of human term placenta incubated in vitro was studied. Doses considered as being physiological of 0.09 and 0.9 microM had a stimulatory effect on the conversion (p less than 0.008 to 0.016). However, a supraphysiological dose of 45 microM showed an inhibitory activity related to the maximal stimulation (p less than 0.03). A dose of 0.9 microM E2 favoured the accumulation of (3H)-progesterone in the tissue (p less than 0.05). These results suggest that E2 may regulate the synthesis of progesterone in human term placenta.


Asunto(s)
Estradiol/farmacología , Placenta/metabolismo , Pregnenolona/metabolismo , Progesterona/biosíntesis , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Técnicas In Vitro , Cinética , Placenta/efectos de los fármacos , Embarazo , Tritio
13.
ALTEX ; 16(4): 267-270, 1999.
Artículo en Alemán | MEDLINE | ID: mdl-11107326

RESUMEN

In the contemporary controversy about the legitimacy of vivisection a few basic assumptions are shared by nearly all participants of the discussion. (I) Pure Research in the service of medicine is of great value for humankind. It contributes to prolonging human life and the alleviation and prevention of human suffering. (II) Brain surgery for the sole purpose of pure research is morally unacceptable in the case of any human being. (III) Primates are sensitive beings which lead a rich social life and are endowed with remarkable intellectual capacities. (IV) Primates have a moral standing, possibly to a lesser degree compared with human beings, certain acts are therefore an injustice toward them. The controversy then is about the question whether premise (I) outweighs (IV), i.e. whether the benefit of the pure research is from a moral point of view more important than the suffering of innocent primates. I shall present four arguments against such a conclusion. 1) According to premise (I) brain surgery on human beings for the sole purpose of pure research is morally unacceptable. Since this prohibition is meant to include all human beings it cannot rest on the exclusive human possession of reason because e.g. some mentally handicapped human beings lack this faculty. All other properties which may be named as basis for the ascription of a moral status which forbids brain surgery for pure research, are possessed also by some animals, especially primates; therefore it is impossible to deny them the same moral status. 2) Brain surgery on primates is confronted with an insoluble dilemma: If the characteristics of the primate brain are very similar to that of human beings, the scientific benefit is obvious, but the procedure appears to be morally unacceptable exactly because of this similarity. If, on the other hand, the characteristics differ significantly, brain surgery may seem legitimate but the scientific benefit becomes doubtful at best. 3) We could quite easily save hundreds of human lives if e.g. speed limits would be reduced (say) by half. Most of us, however, are unwilling to accept such a loss of quality of life in order to save a certain number of human lives. Since we are no prepared to pay this comparatively modest price, we have, in my eyes, no moral right to impose considerable pain and suffering on a primate to save human lives. 4) Pure research in the service of human medicine is from a moral point of view of great importance. Since most of the work in this area is done or financed by private corporations and not by state institutions, from a economical point of view the aim consists in making profit. Since the latter aspect has gained more and more weight in the last years the moral worth of pure research cannot rule out any other moral concern.

14.
Mol Biol Rep ; 9(3): 203-8, 1983 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-6633522

RESUMEN

Human term placenta RNA and polyadenylated mRNA were prepared using guanidine HCl and oligo (dT)-cellulose affinity chromatography. Both fractions translated in a wheat germ cell-free system showed, under optimal condition of K+ and Mg++ ions and spermidine, about 9 times activity for RNA and 15-25 times for poly(A+) mRNA greater than the control. Homogenization of the tissue at high speed compared to that at low speed improved 4-fold activity. Analysis of tritiated products by SDS-Polyacrylamide gel electrophoresis and detected by fluorography showed more than ten different intensity bands ranging between 12 and 66 kD. According to the results obtained, guanidine HCl is an advantageous procedure for the extraction of RNA from this nuclease-rich tissue compared with that obtained with phenol extraction, in both activity and in larger translation products.


Asunto(s)
Placenta/análisis , Biosíntesis de Proteínas , ARN Mensajero/metabolismo , Animales , Sistema Libre de Células , Femenino , Guanidina , Guanidinas , Humanos , Hígado/análisis , Embarazo , Ratas
15.
J Reprod Fertil ; 45(3): 509-12, 1975 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1206648

RESUMEN

The secretion in vitro of HCG and proteins was studied in fragments of placenta from women in the first trimester of pregnancy by a pulse-chase system. A 10-min pulse with [3H]leucine was used. It was concluded that the approximate half-time of release of HCG was 150 min. Proteins precipitable with trichloroacetic acid had a bi-exponential pattern, the half-times of release being 100 and 270 min. These rates of release indicate that the HCG produced by the early placenta was rapidly passed into the circulation rather than stored.


Asunto(s)
Gonadotropina Coriónica/metabolismo , Placenta/metabolismo , Femenino , Humanos , Técnicas In Vitro , Leucina/metabolismo , Embarazo , Primer Trimestre del Embarazo , Biosíntesis de Proteínas , Factores de Tiempo , Ácido Tricloroacético
16.
Mol Biol Rep ; 13(1): 45-51, 1988.
Artículo en Inglés | MEDLINE | ID: mdl-3262195

RESUMEN

Cell-free translation of polyadenylated mRNA from human term placenta in a wheat germ extract, after immunoprecipitation with antibodies directed against purified pregnant serum SP1, yielded a single polypeptide of 31 kDa. Addition of dog pancreatic microsomal vesicles to the translation system resulted in the appearance of two polypeptides, one of them of 46 kDa and the other of 28 kDa. Both polypeptides were protected from limited proteolysis and when the assay was performed with lytic detergent concentrations in addition to proteases, this protection was abolished indicating that the polypeptides were segregated into the microsomal vesicles. The cleavage of a signal peptide of 3 kDa from the 31 kDa primary translation product gives rise to 28 kDa and accounts for the slight increase in electrophoretic mobility. The treatment of the immunoprecipitated products with Endoglycosidase H and alpha-mannosidase, suggested that only the 46 kDa polypeptide is a glycoprotein. From the results obtained we conclude that SP1 is synthesized and processed to a glycoprotein of 46 kDa which would be a protomeric form of the oligomers reported in pregnant serum by other authors.


Asunto(s)
Placenta/metabolismo , Poli A/genética , Proteínas Gestacionales/genética , Glicoproteínas beta 1 Específicas del Embarazo/genética , Biosíntesis de Proteínas , ARN Mensajero/genética , Sistema Libre de Células , Cromatografía de Afinidad , Femenino , Humanos , Membranas Intracelulares/metabolismo , Microsomas/metabolismo , Embarazo
17.
J Steroid Biochem ; 32(3): 413-20, 1989 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2523011

RESUMEN

The effects of 50 microM of progesterone (P4), estradiol (E2), estrone (E1), estriol (E3), dehydroepiandrosterone (DHIA), androstenedione (delta 4) and testosterone (T) on the bioconversion of [3H]pregnenolone (6 nM) to [3H]P4 were investigated by incubating 200 mg of tissue fragments as well as equivalent aliquots of microsomes from human term placenta during 30 min. All the steroids assayed, except E3, significantly inhibited the [3H]P4 formation in a microsome incubation system with respect to the control assay (P less than 0.001). Conversely in a tissue incubation system. P4, E1 as well as E3 had no effect on [3H]pregnenolone bioconversion while E2 slightly decreased the [3H]P4 formation (P less than 0.05) compared with the control. A significant inhibition was observed in this system with the other steroids (P less than 0.001). To investigate these apparent different results of inhibition-noninhibition of the same steroids irrespective of the system of incubation used, the effects of P4, E2 and T on 3 beta-hydroxysteroid dehydrogenase/isomerase (3 beta-HSD) activity were studied in tissue fragments and microsomes in kinetic terms. The results found indicate that these steroids inhibited in a competitive fashion the 3 beta-HSD activity in both systems. The different Ki values found in tissue fragments and microsomes respectively for P4 (1.8 microM vs 0.5 microM), E2 (2.3 microM vs 0.6 microM) and T (0.25 microM vs 0.3 microM) explain the bioconversion results obtained in presence of 50 microM of the same steroids. These results include inhibition of [3H]P4 formation by T in tissue fragments as well as in microsomes whereas P4 and E2 inhibited the [3H]P4 formation only in microsomes. Furthermore, the comparison of these Ki values with the available data of intraplacental and circulating concentrations of the same steroids in human term pregnancy suggest that only P4 would be expected to cause marked 3 beta-HSD inhibition in physiological conditions.


Asunto(s)
3-Hidroxiesteroide Deshidrogenasas/metabolismo , Hormonas Esteroides Gonadales/farmacología , Microsomas/enzimología , Placenta/enzimología , Progesterona/farmacología , 3-Hidroxiesteroide Deshidrogenasas/antagonistas & inhibidores , Androstenodiona/farmacología , Unión Competitiva , Deshidroepiandrosterona/farmacología , Estradiol/farmacología , Estriol/farmacología , Estrona/farmacología , Femenino , Humanos , Cinética , Placenta/ultraestructura , Embarazo , Pregnenolona/metabolismo , Progesterona/biosíntesis , Testosterona/farmacología
18.
Biochem Int ; 18(5): 999-1008, 1989 May.
Artículo en Inglés | MEDLINE | ID: mdl-2528957

RESUMEN

Transcriptional studies of the placental protein Pregnancy Specific beta 1-Glycoprotein (SP1 or PS beta G) gene with a cDNA probe in Northern blot analysis showed 15-20 folds mRNA increase in term placenta compared with early placenta and hydatiform mole. This value parallels the SP1 amount translated in wheat germ cell-free system. We conclude that SP1 biosynthesis is regulated at transcriptional level during placental development and a similar mechanism would occur in hydatiform mole which is a hyperplastic trophoblast tumor.


Asunto(s)
Regulación de la Expresión Génica , Mola Hidatiforme/genética , Placenta , Proteínas Gestacionales/genética , Glicoproteínas beta 1 Específicas del Embarazo/genética , Bacteriófago lambda/genética , Northern Blotting , Femenino , Humanos , Hibridación de Ácido Nucleico , Embarazo , Biosíntesis de Proteínas , ARN Mensajero/aislamiento & purificación , Transcripción Genética
19.
Mol Biol Rep ; 12(1): 55-9, 1987.
Artículo en Inglés | MEDLINE | ID: mdl-2888015

RESUMEN

Poly (A+)-mRNA obtained from human term placenta using guanidine HCl and oligo (dT) cellulose chromatography was translated in a wheat germ cell-free system. SDS-polyacrylamide gel electrophoresis analysis of the translation products revealed the presence of several polypeptides with molecular weights ranging from 10 KD to 70 KD. A single protein band representing around 1% of the total radioactive proteins synthesized in the presence of 2.5 micrograms of mRNA was isolated by immunoprecipitation, using specific antiserum against either the native 'Pregnancy-specific beta 1-glycoprotein' or a reduced and carboxymethylated derivative. The molecular weight of 31-2 KD of this translation product corresponding to the nonprocessed precursor could account for the 43 KD value assigned to the protein purified form human pregnant serum.


Asunto(s)
Placenta/análisis , Plantas/metabolismo , Proteínas Gestacionales/biosíntesis , Glicoproteínas beta 1 Específicas del Embarazo/biosíntesis , ARN Mensajero/metabolismo , Sistema Libre de Células , Electroforesis en Gel de Poliacrilamida , Femenino , Humanos , Peso Molecular , Poli A/metabolismo , Embarazo , Biosíntesis de Proteínas , Triticum
20.
Mol Biol Rep ; 16(4): 255-62, 1992 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1454058

RESUMEN

The pregnancy-specific beta 1 glycoprotein (PSG) genes encode a group of heterogeneous proteins produced in large amounts by the human syncytiotrophoblast. Their expression seems to be regulated at the transcriptional level during normal pregnancy. In the present work, we isolated from a human placental library a 17 kb genomic fragment corresponding to a member of the PSG multigene family. DNA sequence analysis of 1190 nucleotides upstream of the translational start and of the first intron, revealed the presence of several putative regulatory sequences. In a transient chloramphenicol acetyltransferase expression assay, 5' flanking sequences within 123 nucleotides upstream to the first major transcription initiation site, functioned as a strong promoter in COS-7 cells. Meanwhile, sequences 5' further upstream had the ability to abolish this promoter activity. The sequence analyzed did not contain any obvious TATA-like boxes or G+C-rich regions, suggesting the existence of unique promoter elements implicated in transcription initiation and regulation of this PSG gene family member.


Asunto(s)
Familia de Multigenes , Glicoproteínas beta 1 Específicas del Embarazo/genética , Regiones Promotoras Genéticas , Secuencia de Aminoácidos , Secuencia de Bases , Línea Celular , Clonación Molecular , ADN , Humanos , Datos de Secuencia Molecular , Secuencias Reguladoras de Ácidos Nucleicos , Mapeo Restrictivo
SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda