956 resultados para Insulin-like growth factor-binding proteins
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Objective: To analyze the vascularization of the endometrium via hysteroscopy and to assess its correlation with angiogenic factor gene expression and embryo implantation rate.Design: Cross-sectional study.Setting: Public university hospital.Patient(s): Patients undergoing hysteroscopy for supposed infertility.Intervention(s): Endometrial quality assessment according to Sakumoto-Masamoto, performed in the early secretory phase of the cycle. Collection of an endometrial tissue biopsy.Main Outcome Measure(s): RNA extraction, reverse transcription, and determination of gene expression of angiogenesis- and implantation-relevant factors using quantitative polymerase chain reaction. Retrieval of pregnancy information from the medical records.Result(s): Good quantity/quality RNA with infertility history was obtained from 63 participating women. Those with a "good" endometrium and subsequent pregnancy showed increased gene expression for placenta growth factor when compared with patients with a "bad" endometrium and who did not succeed with pregnancy to date. Nonpregnant women with a "good" endometrium presented an intermediate result. No significant differences were observed for several other genes tested, but trends in the same direction were observed.Conclusion(s): This study demonstrates for the first time that endometrial PLGF expression corresponds to the hysteroscopic appearance of the endometrium, and therefore has potential as a clinically relevant prognosticator for infertility treatment success. (Fertil Steril (R) 2011;96:663-8. (C)2011 by American Society for Reproductive Medicine.)
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Bovine growth hormone (bGH) and epidermal growth factor (EGF) increased the activity of ornithine decarboxylase (ODC) in brain cell aggregates cultured in a serum-free chemically defined medium. ODC is considered as a marker of cell growth and differentiation. The effect of bGH and EGF on myelination was investigated by measuring two myelin markers, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and myelin basic protein (MBP). EGF treatment at days 2 and 5 caused a dose-dependent increase of both myelin markers at culture day 12. This increase could still be observed at culture day 19, indicating a prolonged action of EGF. The continual presence of bGH in the culture medium produced a large accumulation of MBP at day 19. This effect was dose-dependent and required the presence of triiodothyronine (T3). In contrast, the effect of bGH on CNP activity did not require the presence of T3. This is the first report showing a direct effect of bGH on CNS myelination in vitro and of EGF on both MBP accumulation and ODC activity.
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Fibroblast growth factor 23 (FGF23) is a circulating factor secreted by osteocytes that is essential for phosphate homeostasis. In kidney proximal tubular cells FGF23 inhibits phosphate reabsorption and leads to decreased synthesis and enhanced catabolism of 1,25-dihydroxyvitamin D3 (1,25[OH]2 D3 ). Excess levels of FGF23 cause renal phosphate wasting and suppression of circulating 1,25(OH)2 D3 levels and are associated with several hereditary hypophosphatemic disorders with skeletal abnormalities, including X-linked hypophosphatemic rickets (XLH) and autosomal recessive hypophosphatemic rickets (ARHR). Currently, therapeutic approaches to these diseases are limited to treatment with activated vitamin D analogues and phosphate supplementation, often merely resulting in partial correction of the skeletal aberrations. In this study, we evaluate the use of FGFR inhibitors for the treatment of FGF23-mediated hypophosphatemic disorders using NVP-BGJ398, a novel selective, pan-specific FGFR inhibitor currently in Phase I clinical trials for cancer therapy. In two different hypophosphatemic mouse models, Hyp and Dmp1-null mice, resembling the human diseases XLH and ARHR, we find that pharmacological inhibition of FGFRs efficiently abrogates aberrant FGF23 signaling and normalizes the hypophosphatemic and hypocalcemic conditions of these mice. Correspondingly, long-term FGFR inhibition in Hyp mice leads to enhanced bone growth, increased mineralization, and reorganization of the disturbed growth plate structure. We therefore propose NVP-BGJ398 treatment as a novel approach for the therapy of FGF23-mediated hypophosphatemic diseases.
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The delivery kinetics of growth factors has been suggested to play an important role in the regeneration of peripheral nerves following axotomy. In this context, we designed a nerve conduit (NC) with adjustable release kinetics of nerve growth factor (NGF). A multi-ply system was designed where NC consisting of a polyelectrolyte alginate/chitosan complex was coated with layers of poly(lactide-co-glycolide) (PLGA) to control the release of embedded NGF. Prior to assessing the in vitro NGF release from NC, various release test media, with and without stabilizers for NGF, were evaluated to ensure adequate quantification of NGF by ELISA. Citrate (pH 5.0) and acetate (pH 5.5) buffered saline solutions containing 0.05% Tween 20 yielded the most reliable results for ELISA active NGF. The in vitro release experiments revealed that the best results in terms of reproducibility and release control were achieved when the NGF was embedded between two PLGA layers and the ends of the NC tightly sealed by the PLGA coatings. The release kinetics could be efficiently adjusted by accommodating NGF at different radial locations within the NC. A sustained release of bioactive NGF in the low nanogram per day range was obtained for at least 15days. In conclusion, the developed multi-ply NGF loaded NC is considered a suitable candidate for future implantation studies to gain insight into the relationship between local growth factor availability and nerve regeneration.
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BACKGROUND: Lapatinib is an effective anti-HER2 therapy in advanced breast cancer and docetaxel is one of the most active agents in breast cancer. Combining these agents in pre-treated patients with metastatic disease had previously proved challenging, so the primary objective of this study aimed to determine the maximum tolerated dose (MTD) in treatment-naive patients, by identifying acute dose-limiting toxicities (DLT) during cycle 1 in the first part of a phases 1-2 neoadjuvant European Organisation for Research and Treatment of Cancer (EORTC) trial. PATIENTS AND METHODS: Patients with large operable or locally-advanced HER2 positive breast cancer were treated with continuous lapatinib, and docetaxel every 21days for 4 cycles. Dose levels (DLs) were: 1000/75, 1250/75, 1000/85, 1250/85, 1000/100 and 1250/100 (mg/day)/(mg/m(2)). RESULTS: Twenty-one patients were included. Two DLTs occurred at dose level 5 (1000/100); one grade 4 neutropenia ⩾7days and one febrile neutropenia. A further 3 patients were therefore treated at the same dose with prophylactic granulocyte-colony stimulating factor (G-CSF), and 3 patients at dose level 6. No further DLTs were observed. CONCLUSIONS: Our recommended dose for phase II is lapatinib 1000mg/day and docetaxel 100mg/m(2) with G-CSF in HER2 positive non-metastatic breast cancer. The dose of lapatinib should have been 1250mg/day but we were mindful of the high rate of treatment discontinuation in GeparQuinto with lapatinib 1250mg/day combined with docetaxel. No grade 3-4 diarrhoea was observed. Pharmacodynamics analysis suggests that concomitant medications altering P-glycoprotein activity (in addition to lapatinib) can modify toxicity, including non-haematological toxicities. This needs verification in larger trials, where it may contribute to understanding the sources of variability in clinical toxicity and treatment discontinuation.
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HTPSELEX is a public database providing access to primary and derived data from high-throughput SELEX experiments aimed at characterizing the binding specificity of transcription factors. The resource is primarily intended to serve computational biologists interested in building models of transcription factor binding sites from large sets of binding sequences. The guiding principle is to make available all information that is relevant for this purpose. For each experiment, we try to provide accurate information about the protein material used, details of the wet lab protocol, an archive of sequencing trace files, assembled clone sequences (concatemers) and complete sets of in vitro selected protein-binding tags. In addition, we offer in-house derived binding sites models. HTPSELEX also offers reasonably large SELEX libraries obtained with conventional low-throughput protocols. The FTP site contains the trace archives and database flatfiles. The web server offers user-friendly interfaces for viewing individual entries and quality-controlled download of SELEX sequence libraries according to a user-defined sequencing quality threshold. HTPSELEX is available from ftp://ftp.isrec.isb-sib.ch/pub/databases/htpselex/ and http://www.isrec.isb-sib.ch/htpselex.
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The human primary auditory cortex (AI) is surrounded by several other auditory areas, which can be identified by cyto-, myelo- and chemoarchitectonic criteria. We report here on the pattern of calcium-binding protein immunoreactivity within these areas. The supratemporal regions of four normal human brains (eight hemispheres) were processed histologically, and serial sections were stained for parvalbumin, calretinin or calbindin. Each calcium-binding protein yielded a specific pattern of labelling, which differed between auditory areas. In AI, defined as area TC [see C. von Economo and L. Horn (1930) Z. Ges. Neurol. Psychiatr.,130, 678-757], parvalbumin labelling was dark in layer IV; several parvalbumin-positive multipolar neurons were distributed in layers III and IV. Calbindin yielded dark labelling in layers I-III and V; it revealed numerous multipolar and pyramidal neurons in layers II and III. Calretinin labelling was lighter than that of parvalbumin or calbindin in AI; calretinin-positive bipolar and bitufted neurons were present in supragranular layers. In non-primary auditory areas, the intensity of labelling tended to become progressively lighter while moving away from AI, with qualitative differences between the cytoarchitectonically defined areas. In analogy to non-human primates, our results suggest differences in intrinsic organization between auditory areas that are compatible with parallel and hierarchical processing of auditory information.
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Abstract Telomeres, the natural ends of chromosomes, need to be protected from chromosome end fusions, aberrant homologous recombination and degradation. In humans, chromosome ends are specified through arrays of tandemly repeated 5'-TTAGGG-3' hexamers, ending in a 3' overhang. A complex formed by the six proteins TRF1, TRF2, hRap1, TIN2, TPP1 and POT1 specifically assocìates with and protects telomeres. Telomeres are maintained by semiconservative DNA replication and by a specialized reverse transcriptase, telomerase, that carries an RNA subunit which templates new telomeric repeat synthesis. The telomeric single stranded (ss) DNA binding protein POT1 protects the telomeric 3' overhang and modulates telomerase-mediated telomere elongation. It is possible that POT1 also influences DNA synthesis during semiconservative DNA replication, which is initiated by the DNA polymerase alpha-primase complex. The heterotrimeric ss DNA-binding protein RPA plays essential roles during DNA replication. RPA binds to ss DNA with high affinity in order to stabilize ss DNA and facilitate nascent strand synthesis at the replication fork. Here we investigate how the two proteins RPA and POT1 contribute to telomere maintenance by regulating semi-conservative DNA replication and telomerase. Using chromatin immunoprecipitation experiments, we show that RPA associates with telomeres during S-phase. Analysis of telomere structure in cells shRNA-depleted for RPA and POT1 reveals that loss of RPA and POT1 causes exposure of single-stranded DNA at telomeres, suggestive of incomplete DNA replication. Biochemical experiments using purified recombinant POT1 and RPA show that saturating telomeric oligonucleotides with POT1 or RPA reduces the primase activity of the DNA polymerase alpha-primase complex and the overall activity of telomerase. POT1 and RPA also increase the primer extension by DNA polymerase alpha-primase complex and the processivity of telomerase under certain conditions, although POT1 increases the activities to a greater extent than RPA. We propose that POT1 is required for proper replication of the lagging strand of telomeres and that some phenotypes observed in POT1-depleted cells may stern from incomplete DNA replication rather than de-protection of the single-stranded overhang. Résumé Les télomères, les extrémités normales des chromosomes linéaires, doivent être protégés des fusions chromosomiques, d'événements de recombinaison homologue aberrants et de phénomènes de dégradation. Chez l'Homme, les extrémités des chromosomes sont constitués d'ADN double brin répétitif de séquence 5'-TTAGGG-3', d'une extension simple brin 3' sortante et d'un complexe protéique formé des six facteurs TRF1, TRF2, hRap1, TIN2, TPP1 et POT1 qui, s'associant à cette séquence, protègent l'ADN télomèrique. Les télomères sont maintenus par la télomérase, une transcriptase inverse capable d'allonger l'extension 3' sortante télomérique. POT1 lie l'ADN simple brin télomérique et module l'élongation des télomères par la télomérase. POT1 pourrait en théorie également influencer la réplication semi-conservative de l'ADN. L'ADN-polymérase Pal alpha-primase amorce et initie la synthèse d'ADN. Pendant la réplication, l'ADN simple brin est stabilisé par RPA, un complexe hétérotrimèrique qui lie l'ADN simple brin. RPA facilite la synthèse du brin naissant à la fourche de réplication. Ici nous avons étudié comment ces deux protéines qui lient l'ADN simple brin, RPA et POT1, régulent la réplication des télomères par la télomérase et la machinerie classique de réplication de l'ADN. Par immunoprécipitation de chromatine (ChIP), nous montrons que RPA est localisé aux télomères lors de la phase S du cycle cellulaire. De plus, l'analyse de la structure des télomeres indique que !a perte de RPA ou de POT1 conduit à l'apparition d'ADN simple brin télomérique, suggérant une réplication incomplète de l'ADN télomérique in vivo. Par une approche complémentaire biochimique utilisant les protéines POT1 et RPA recombinantes purifiées, nous montrons également que la liaison de POT1 ou de RPA à des oligonucléotides télomériques bloque l'activité primase du complexe polymérase alpha/primase et réduit l'activité télomérase sur ces substrats. En revanche, leur liaison augmente l'activité ADN-polymérase du complexe polymérase alpha/primase, ainsi que fa processivité de la télomérase dans certaines conditions, POT1 étant le plus efficace des deux facteurs. Nous proposons que POT1 est nécessaire à la réplication du brin retardé au niveau des télomères, ce qui suggère que certains phénotypes des cellules déplétés en POT1 puissent résulter d'une réplication incomplète de l'ADN télémétrique plutôt que d'une déprotection de l'extrémité sortante des télomères.
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Macrophages play a critical role in intestinal wound repair. However, the mechanisms of macrophage-assisted wound repair remain poorly understood. We aimed to characterize more clearly the repair activities of murine and human macrophages. Murine macrophages were differentiated from bone marrow cells and human macrophages from monocytes isolated from peripheral blood mononuclear cells of healthy donors (HD) or Crohn's disease (CD) patients or isolated from the intestinal mucosa of HD. In-vitro models were used to study the repair activities of macrophages. We found that murine and human macrophages were both able to promote epithelial repair in vitro. This function was mainly cell contact-independent and relied upon the production of soluble factors such as the hepatocyte growth factor (HGF). Indeed, HGF-silenced macrophages were less capable of promoting epithelial repair than control macrophages. Remarkably, macrophages from CD patients produced less HGF than their HD counterparts (HGF level: 84âeuro0/00±âeuro0/0027âeuro0/00pg/mg of protein and 45âeuro0/00±âeuro0/0034âeuro0/00pg/mg of protein, respectively, for HD and CD macrophages, Pâeuro0/00<âeuro0/000·009) and were deficient in promoting epithelial repair (repairing activity: 90·1âeuro0/00±âeuro0/004·6 and 75·8âeuro0/00±âeuro0/008·3, respectively, for HD and CD macrophages, Pâeuro0/00<âeuro0/000·0005). In conclusion, we provide evidence that macrophages act on wounded epithelial cells to promote epithelial repair through the secretion of HGF. The deficiency of CD macrophages to secrete HGF and to promote epithelial repair might contribute to the impaired intestinal mucosal healing in CD patients.
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Transforming growth factor alpha (TGF alpha) is a polypeptide, which binds to the epidermal growth factor receptor to carry out its function related to cell proliferation and differentiation. The ultrastructural localisation of TGF alpha was studied in both the proximal and the distal colon. The columnar cells, lining the surface epithelium of the proximal colon, showed a strong immunoreactivity in the polyribosomes and in the interdigitations of the lateral membrane. The columnar cells of the crypts and the goblet cells in both the proximal and the distal colon showed the immunostaining in the cis and trans cisternae of the Golgi apparatus. TGF alpha seems to be processed differently in the surface columnar cells and in the crypt columnar cells and goblet cells. Moreover, it probably has different roles in proliferation and differentiation.
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Background and aims: The extent and molecular mechanisms governing plasma extravasation and formation of ascites in cirrhosis are unknown. Vascular endothelial growth factor-A (VEGF-A) and angiopoietin-2 (Ang-2) are endogenous substances with powerful vascular permeability effects. We assessed regional blood flow, vascular leakage, mRNA and tissular expression of VEGF-A and Ang-2 and vascular permeability following VEGF receptor 2 blockade in control and cirrhotic rats to define the vascular territories showing altered vascular permeability in cirrhosis and to determine whether VEGF-A and Ang-2 are involved in this phenomenon. Methods: Arterial blood flow was analysed with the coloured microsphere method. Vascular leakage was measured and visualised with the dye Evan¿s Blue and colloidal carbon techniques, respectively. VEGF-A and Ang-2 expression were determined by real-time polymerase chain reaction (RT-PCR), immunohistochemistry and western blot. The effect on vascular permeability induced by VEGFR2 blockade was assessed by administration of the receptor inhibitor SU11248. Results: Arterial blood flow was increased in the mesentery, pancreas and small intestine but not in the kidney and spleen of cirrhotic rats as compared to controls. Increased vascular leakage was observed in the mesentery and liver, where colloidal carbon spread from microvessels to the adjacent fibrotic tracts. Increased hepatic and mesenteric expression of VEGF-A and Ang-2 was found in cirrhotic rats as compared to controls. Blockade of VEGFR2 markedly reduced hepatic and mesenteric vascular leakage in cirrhotic rats. Conclusions: Enhanced endothelial permeability is restricted to the hepatic and mesenteric vascular beds in cirrhotic rats with ascites and VEGF-A and Ang-2 are key factors in the signalling pathways regulating this dysfunction.
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The subdivisions of human inferior colliculus are currently based on Golgi and Nissl-stained preparations. We have investigated the distribution of calcium-binding protein immunoreactivity in the human inferior colliculus and found complementary or mutually exclusive localisations of parvalbumin versus calbindin D-28k and calretinin staining. The central nucleus of the inferior colliculus but not the surrounding regions contained parvalbumin-positive neuronal somata and fibres. Calbindin-positive neurons and fibres were concentrated in the dorsal aspect of the central nucleus and in structures surrounding it: the dorsal cortex, the lateral lemniscus, the ventrolateral nucleus, and the intercollicular region. In the dorsal cortex, labelling of calbindin and calretinin revealed four distinct layers.Thus, calcium-binding protein reactivity reveals in the human inferior colliculus distinct neuronal populations that are anatomically segregated. The different calcium-binding protein-defined subdivisions may belong to parallel auditory pathways that were previously demonstrated in non-human primates, and they may constitute a first indication of parallel processing in human subcortical auditory structures.