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López-Fernández MF, López-Berges C, Martín R, Pardo A, Ramos FJ, Batlle J. Abnormal Structure of von Willebrand Factor in Myeloproliferative Syndrome Is Associated to Either Thrombotic or Bleeding Diathesis. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1645964] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryThe multimeric and subunit patterns of plasma von Willebrand factor (vWF) were analyzed in eight patients with myeloproliferative syndrome (MS) in order to investigate the possible existence of heterogeneity in the “in vivo” proteolytic cleavage of the protein, previously observed in this entity. Six patients lacked large vWF multimers, five of them having normal bleeding times (BT) and clinically documented episodes of thrombotic origin, whereas one patient had long BT and bleeding symptoms. Seven patients showed a relative increase in the 176 kDa subunit fragment while the 189 kDa polypeptide was increased in only one. In addition, another patient (and prior to any therapy) showed the presence of a new fragment of approximately 95 kDa which disappeared after Busulfan therapy. The collection of blood from these patients with proteinase inhibitors did not correct the abnormalities.The infusion of DDAVP to two patients with abnormal vWF was accompanied by: the appearance of larger vWF multimers which disappeared rapidly from plasma; an increase in the relative proportion of the satellite bands of each multimer and a further increase of the 176 kDa fragment. These data point to some heterogeneity in the vWF abnormality present in MS which may be related in part to a variable degree of proteolysis of vWF occurring “in vivo” rather than “in vitro”, and which may be associated to either a thrombotic or a bleeding diathesis. They also suggest that despite the presence of abnormal, already proteolyzed vWF, DDAVP-enhanced proteolysis occurs in MS to a similar extent to what is described in normal individuals.
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Affiliation(s)
- M F López-Fernández
- The Department of Hematology, Hospital Clínico, Universidad de Salamanca, Spain
| | - C López-Berges
- The Department of Hematology, Hospital Clínico, Universidad de Salamanca, Spain
| | - R Martín
- The Department of Hematology, Hospital Clínico, Universidad de Salamanca, Spain
| | - A Pardo
- The Department of Hematology, Hospital Ramon y Cajal, Madrid, Spain
| | - F J Ramos
- The Department of Hematology, Hospital Clínico, Universidad de Salamanca, Spain
| | - J Batlle
- The Department of Hematology, Hospital Clínico, Universidad de Salamanca, Spain
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2
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Parenti I, Gervasini C, Pozojevic J, Wendt KS, Watrin E, Azzollini J, Braunholz D, Buiting K, Cereda A, Engels H, Garavelli L, Glazar R, Graffmann B, Larizza L, Lüdecke HJ, Mariani M, Masciadri M, Pié J, Ramos FJ, Russo S, Selicorni A, Stefanova M, Strom TM, Werner R, Wierzba J, Zampino G, Gillessen-Kaesbach G, Wieczorek D, Kaiser FJ. Expanding the clinical spectrum of the 'HDAC8-phenotype' - implications for molecular diagnostics, counseling and risk prediction. Clin Genet 2016; 89:564-73. [PMID: 26671848 DOI: 10.1111/cge.12717] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/30/2015] [Accepted: 12/12/2015] [Indexed: 01/25/2023]
Abstract
Cornelia de Lange syndrome (CdLS) is a clinically heterogeneous disorder characterized by typical facial dysmorphism, cognitive impairment and multiple congenital anomalies. Approximately 75% of patients carry a variant in one of the five cohesin-related genes NIPBL, SMC1A, SMC3, RAD21 and HDAC8. Herein we report on the clinical and molecular characterization of 11 patients carrying 10 distinct variants in HDAC8. Given the high number of variants identified so far, we advise sequencing of HDAC8 as an indispensable part of the routine molecular diagnostic for patients with CdLS or CdLS-overlapping features. The phenotype of our patients is very broad, whereas males tend to be more severely affected than females, who instead often present with less canonical CdLS features. The extensive clinical variability observed in the heterozygous females might be at least partially associated with a completely skewed X-inactivation, observed in seven out of eight female patients. Our cohort also includes two affected siblings whose unaffected mother was found to be mosaic for the causative mutation inherited to both affected children. This further supports the urgent need for an integration of highly sensitive sequencing technology to allow an appropriate molecular diagnostic, genetic counseling and risk prediction.
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Affiliation(s)
- I Parenti
- Sektion für Funktionelle Genetik am Institut für Humangenetik Lübeck, Universität zu Lübeck, Lübeck, Germany.,Medical Genetics, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - C Gervasini
- Medical Genetics, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - J Pozojevic
- Sektion für Funktionelle Genetik am Institut für Humangenetik Lübeck, Universität zu Lübeck, Lübeck, Germany
| | - K S Wendt
- Department of Cell Biology, Erasmus MC, Rotterdam, The Netherlands
| | - E Watrin
- Faculté de Médecine, Institut de Génétique et Développement de Rennes, UMR6290-CNRS, Rennes, France
| | - J Azzollini
- Medical Genetics, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - D Braunholz
- Sektion für Funktionelle Genetik am Institut für Humangenetik Lübeck, Universität zu Lübeck, Lübeck, Germany
| | - K Buiting
- Institut für Humangenetik, Universitätsklinikum Düsseldorf, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - A Cereda
- U.O.S. Genetica Clinica Pediatrica, Clinica Pediatrica Fondazione MBBM, A.O. S.Gerardo, Monza, Italy
| | - H Engels
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - L Garavelli
- Clinical Genetics Unit, Department of Obstetrics and Pediatrics, IRCCS S. Maria Nuova Hospital, Reggio Emilia, Italy
| | - R Glazar
- The Center for Medical Genetics GENESIS Poznan, Poland
| | - B Graffmann
- Department of Pediatrics, University Hospital Linköping, Linköping, Sweden
| | - L Larizza
- Laboratory of Medical Cytogenetics and Molecular Genetics, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - H J Lüdecke
- Institut für Humangenetik, Universitätsklinikum Düsseldorf, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - M Mariani
- U.O.S. Genetica Clinica Pediatrica, Clinica Pediatrica Fondazione MBBM, A.O. S.Gerardo, Monza, Italy
| | - M Masciadri
- Laboratory of Medical Cytogenetics and Molecular Genetics, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - J Pié
- Unit of Clinical Genetics and Functional Genomics, Departments of Pharmacology-Physiology and Pediatrics, Medical School, University of Zaragoza, CIBERER-GCV and ISS-Aragon, Zaragoza, Spain
| | - F J Ramos
- Unit of Clinical Genetics and Functional Genomics, Departments of Pharmacology-Physiology and Pediatrics, Medical School, University of Zaragoza, CIBERER-GCV and ISS-Aragon, Zaragoza, Spain.,Unidad de Genetica Clınica, Servicio de Pediatrıa, Hospital Clınico Universitario "Lozano Blesa", CIBERER-GCV and ISS-Aragon, Zaragoza, Spain
| | - S Russo
- Laboratory of Medical Cytogenetics and Molecular Genetics, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - A Selicorni
- U.O.S. Genetica Clinica Pediatrica, Clinica Pediatrica Fondazione MBBM, A.O. S.Gerardo, Monza, Italy
| | - M Stefanova
- Department of Clinical Genetics, University Hospital Linköping, Linköping, Sweden
| | - T M Strom
- Institute of Human Genetics, Technische Universität München, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - R Werner
- Division of Experimental Paediatric Endocrinology and Diabetes, Department of Paediatrics and Adolescent Medicine, University of Lübeck, Lübeck, Germany
| | - J Wierzba
- Department and Clinic of Pediatrics, Hematooncology, Oncology and Endocrinology, Medical University of Gdańsk, Gdańsk, Poland.,Department of General Nursing, Medical University of Gdańsk, Gdańsk, Poland
| | - G Zampino
- Birth Defects Unit, Department of Pediatrics, Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - D Wieczorek
- Institut für Humangenetik, Universitätsklinikum Düsseldorf, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - F J Kaiser
- Sektion für Funktionelle Genetik am Institut für Humangenetik Lübeck, Universität zu Lübeck, Lübeck, Germany
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3
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Leiser SF, Miller H, Rossner R, Fletcher M, Leonard A, Primitivo M, Rintala N, Ramos FJ, Miller DL, Kaeberlein M. Cell nonautonomous activation of flavin-containing monooxygenase promotes longevity and health span. Science 2015; 350:1375-1378. [PMID: 26586189 DOI: 10.1126/science.aac9257] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/03/2015] [Indexed: 12/28/2022]
Abstract
Stabilization of the hypoxia-inducible factor 1 (HIF-1) increases life span and health span in nematodes through an unknown mechanism. We report that neuronal stabilization of HIF-1 mediates these effects in Caenorhabditis elegans through a cell nonautonomous signal to the intestine, which results in activation of the xenobiotic detoxification enzyme flavin-containing monooxygenase-2 (FMO-2). This prolongevity signal requires the serotonin biosynthetic enzyme TPH-1 in neurons and the serotonin receptor SER-7 in the intestine. Intestinal FMO-2 is also activated by dietary restriction (DR) and is necessary for DR-mediated life-span extension, which suggests that this enzyme represents a point of convergence for two distinct longevity pathways. FMOs are conserved in eukaryotes and induced by multiple life span-extending interventions in mice, which suggests that these enzymes may play a critical role in promoting health and longevity across phyla.
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Affiliation(s)
- Scott F Leiser
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Hillary Miller
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Ryan Rossner
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Marissa Fletcher
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Alison Leonard
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Melissa Primitivo
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Nicholas Rintala
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Fresnida J Ramos
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Dana L Miller
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
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Huemer M, Bürer C, Ješina P, Kožich V, Landolt MA, Suormala T, Fowler B, Augoustides-Savvopoulou P, Blair E, Brennerova K, Broomfield A, De Meirleir L, Gökcay G, Hennermann J, Jardine P, Koch J, Lorenzl S, Lotz-Havla AS, Noss J, Parini R, Peters H, Plecko B, Ramos FJ, Schlune A, Tsiakas K, Zerjav Tansek M, Baumgartner MR. Clinical onset and course, response to treatment and outcome in 24 patients with the cblE or cblG remethylation defect complemented by genetic and in vitro enzyme study data. J Inherit Metab Dis 2015; 38:957-67. [PMID: 25526710 DOI: 10.1007/s10545-014-9803-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 12/01/2014] [Accepted: 12/02/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND The cobalamin E (cblE) (MTRR, methionine synthase reductase) and cobalamin G (cblG) (MTR, methionine synthase) defects are rare inborn errors of cobalamin metabolism leading to impairment of the remethylation of homocysteine to methionine. METHODS Information on clinical and laboratory data at initial full assessment and during the course of the disease, treatment, outcome and quality of life was obtained in a survey-based, retrospective study from physicians caring for patients with the CblE or CblG defect. In addition, data on enzyme studies in cultured skin fibroblasts and mutations in the MTRR and MTR gene were analysed. RESULTS In 11 cblE and 13 cblG patients, failure to thrive, feeding problems, delayed milestones, muscular hypotonia, cognitive impairment and macrocytic anaemia were the most frequent symptoms. Delay in diagnosis depended on age at first symptom and clinical pattern at presentation and correlated significantly with impaired communication abilities at follow-up. Eighteen/22 patients presented with brain atrophy or white matter disease. Biochemical response to treatment with variable combinations of betaine, cobalamin, folate was significant. The overall course was considered improving (n = 8) or stable (n = 15) in 96% of patients, however the average number of CNS symptoms per patient increased significantly over time and 16 of 23 patients were classified as developmentally delayed or severely handicapped. In vitro enzyme analysis data showed no correlation with outcome. Predominantly private mutations were detected and no genotype- phenotype correlations evident. CONCLUSIONS The majority of patients with the cblE and cblG defect show limited clinical response to treatment and have neurocognitive impairment.
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Affiliation(s)
- M Huemer
- Division of Metabolic Diseases and Children's Research Center, University Children's Hospital Zürich, Steinwiesstr. 75, Zurich, Switzerland,
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Baquero-Montoya C, Gil-Rodríguez MC, Teresa-Rodrigo ME, Hernández-Marcos M, Bueno-Lozano G, Bueno-Martínez I, Remeseiro S, Fernández-Hernández R, Bassecourt-Serra M, Rodríguez de Alba M, Queralt E, Losada A, Puisac B, Ramos FJ, Pié J. Could a patient with SMC1A duplication be classified as a human cohesinopathy? Clin Genet 2014; 85:446-51. [PMID: 23683030 DOI: 10.1111/cge.12194] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 05/15/2013] [Accepted: 05/15/2013] [Indexed: 01/23/2023]
Abstract
The disorders caused by mutations in genes encoding subunits and accessory proteins of cohesin complex are collectively termed as cohesinopathies. The best known cohesinopathy is Cornelia de Lange Syndrome (CdLS), which is a multisystem developmental disorder characterized by facial dysmorphism, limb malformations, growth and cognitive impairment. Mutations in five genes, encoding subunits of the cohesin complex (SMC1A, SMC3, RAD21) and its regulators (NIPBL, HDAC8), are responsible for ∼ 70% of CdLS cases. We describe a 16-year-old boy with facial dysmorphism, growth retardation, intellectual disability, hirsutism and small hands, who has a small Supernumerary Marker Chromosome (sSMC) present in mosaic form. sSMC is composed of two duplicated segments encompassing 17 genes including SMC1A gene, at the regions Xp11.22 and Xp11.21q11.1. Clinical comparison between our patient with a previously reported individual with a SMC1A duplication and four male carriers of similar sSMC reported in databases, suggest that they all share clinical features related to cohesinopathies. Although our patient does not have the classical CdLS craniofacial phenotype, he has pre and postnatal growth retardation, intellectual disability and mild musculoskeletal anomalies, features commonly seen in patients with cohesinopathies.
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Affiliation(s)
- C Baquero-Montoya
- Unit of Clinical Genetics and Functional Genomics, Departments of Pharmacology-Physiology and Pediatrics, Medical School, University of Zaragoza, Zaragoza, Spain; Service of Pediatrics, Hospital Clínico Universitario "Lozano Blesa", Zaragoza, Spain
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6
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Baquero-Montoya C, Gil-Rodríguez MC, Braunholz D, Teresa-Rodrigo ME, Obieglo C, Gener B, Schwarzmayr T, Strom TM, Gómez-Puertas P, Puisac B, Gillessen-Kaesbach G, Musio A, Ramos FJ, Kaiser FJ, Pié J. Somatic mosaicism in a Cornelia de Lange syndrome patient with NIPBL mutation identified by different next generation sequencing approaches. Clin Genet 2014; 86:595-7. [PMID: 24635725 DOI: 10.1111/cge.12333] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/29/2013] [Accepted: 12/16/2013] [Indexed: 01/24/2023]
Affiliation(s)
- C Baquero-Montoya
- Unit of Clinical Genetics and Functional Genomics, Departments of Pharmacology, Physiology and Pediatrics, Medical School, University of Zaragoza, Zaragoza, Spain
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7
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Johnson SC, Yanos ME, Kayser EB, Quintana A, Sangesland M, Castanza A, Uhde L, Hui J, Wall VZ, Gagnidze A, Oh K, Wasko BM, Ramos FJ, Palmiter RD, Rabinovitch PS, Morgan PG, Sedensky MM, Kaeberlein M. mTOR inhibition alleviates mitochondrial disease in a mouse model of Leigh syndrome. Science 2013; 342:1524-8. [PMID: 24231806 PMCID: PMC4055856 DOI: 10.1126/science.1244360] [Citation(s) in RCA: 382] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Mitochondrial dysfunction contributes to numerous health problems, including neurological and muscular degeneration, cardiomyopathies, cancer, diabetes, and pathologies of aging. Severe mitochondrial defects can result in childhood disorders such as Leigh syndrome, for which there are no effective therapies. We found that rapamycin, a specific inhibitor of the mechanistic target of rapamycin (mTOR) signaling pathway, robustly enhances survival and attenuates disease progression in a mouse model of Leigh syndrome. Administration of rapamycin to these mice, which are deficient in the mitochondrial respiratory chain subunit Ndufs4 [NADH dehydrogenase (ubiquinone) Fe-S protein 4], delays onset of neurological symptoms, reduces neuroinflammation, and prevents brain lesions. Although the precise mechanism of rescue remains to be determined, rapamycin induces a metabolic shift toward amino acid catabolism and away from glycolysis, alleviating the buildup of glycolytic intermediates. This therapeutic strategy may prove relevant for a broad range of mitochondrial diseases.
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Affiliation(s)
- Simon C. Johnson
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Melana E. Yanos
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
- Department of Psychology, University of Washington, Seattle, WA 98195, USA
| | - Ernst-Bernhard Kayser
- Anesthesiology and Pain Medicine, Seattle Children’s Hospital, Seattle, WA 98105, USA
| | - Albert Quintana
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Maya Sangesland
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Anthony Castanza
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Lauren Uhde
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Jessica Hui
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Valerie Z. Wall
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Arni Gagnidze
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Kelly Oh
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Brian M. Wasko
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Fresnida J. Ramos
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Richard D. Palmiter
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | | | - Philip G. Morgan
- Anesthesiology and Pain Medicine, Seattle Children’s Hospital, Seattle, WA 98105, USA
| | - Margaret M. Sedensky
- Anesthesiology and Pain Medicine, Seattle Children’s Hospital, Seattle, WA 98105, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
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Roy AC, Park SR, Cunningham D, Kang YK, Chao Y, Chen LT, Rees C, Lim HY, Tabernero J, Ramos FJ, Kujundzic M, Cardic MB, Yeh CG, de Gramont A. A randomized phase II study of PEP02 (MM-398), irinotecan or docetaxel as a second-line therapy in patients with locally advanced or metastatic gastric or gastro-oesophageal junction adenocarcinoma. Ann Oncol 2013; 24:1567-73. [PMID: 23406728 DOI: 10.1093/annonc/mdt002] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND PEP02 is a novel highly stable liposomal nanocarrier formulation of irinotecan. This randomized phase II study evaluated the efficacy and safety of single agent PEP02 compared with irinotecan or docetaxel in the second-line treatment of advanced oesophago-gastric (OG) cancer. PATIENTS AND METHODS Patients with locally advanced/metastatic disease who had failed one prior chemotherapy regimen were randomly assigned to PEP02 120 mg/m(2), irinotecan 300 mg/m(2) or docetaxel (Taxotere) 75 mg/m(2) every 3 weeks. The primary end point was objective response rate (ORR). Simon's two-stage design was used and the ORR of interest was 20% (α = 0.05, type II error β = 0.10, null hypothesis of ORR was 5%). RESULTS Forty-four patients per arm received treatment, and 124 were assessable for response. The ORR statistical threshold for the first stage was reached in all arms. In the intent-to-treat (ITT) population, ORRs were 13.6% (6/44), 6.8% (3/44) and 15.9% (7/44) in the PEP02, irinotecan and docetaxel arms, respectively. The median progression-free survival (PFS) and overall survival were similar between the trial arms. Commonest grade 3-4 adverse event reported was diarrhoea in the PEP02 and irinotecan groups (27.3% versus 18.2%). CONCLUSION The ORR associated with PEP02 was comparable with docetaxel and numerically greater than that of irinotecan. PEP02 warrants further evaluation in the advanced gastric cancer setting.
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Affiliation(s)
- A C Roy
- Department of Medicine, The Royal Marsden Hospital, Sutton, UK
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9
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Ramos FJ, Chen SC, Garelick MG, Dai DF, Liao CY, Schreiber KH, MacKay VL, An EH, Strong R, Ladiges WC, Rabinovitch PS, Kaeberlein M, Kennedy BK. Rapamycin reverses elevated mTORC1 signaling in lamin A/C-deficient mice, rescues cardiac and skeletal muscle function, and extends survival. Sci Transl Med 2012; 4:144ra103. [PMID: 22837538 DOI: 10.1126/scitranslmed.3003802] [Citation(s) in RCA: 253] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mutations in LMNA, the gene that encodes A-type lamins, cause multiple diseases including dystrophies of the skeletal muscle and fat, dilated cardiomyopathy, and progeria-like syndromes (collectively termed laminopathies). Reduced A-type lamin function, however, is most commonly associated with skeletal muscle dystrophy and dilated cardiomyopathy rather than lipodystrophy or progeria. The mechanisms underlying these diseases are only beginning to be unraveled. We report that mice deficient in Lmna, which corresponds to the human gene LMNA, have enhanced mTORC1 (mammalian target of rapamycin complex 1) signaling specifically in tissues linked to pathology, namely, cardiac and skeletal muscle. Pharmacologic reversal of elevated mTORC1 signaling by rapamycin improves cardiac and skeletal muscle function and enhances survival in mice lacking A-type lamins. At the cellular level, rapamycin decreases the number of myocytes with abnormal desmin accumulation and decreases the amount of desmin in both muscle and cardiac tissue of Lmna(-/-) mice. In addition, inhibition of mTORC1 signaling with rapamycin improves defective autophagic-mediated degradation in Lmna(-/-) mice. Together, these findings point to aberrant mTORC1 signaling as a mechanistic component of laminopathies associated with reduced A-type lamin function and offer a potential therapeutic approach, namely, the use of rapamycin-related mTORC1 inhibitors.
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Affiliation(s)
- Fresnida J Ramos
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
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10
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Abstract
A-type lamins, generated from the LMNA gene by differential splicing, are type V intermediate filament proteins that polymerize to form part of the nuclear lamina, and are of considerable medical interest because missense mutations in LMNA give rise to a wide range of dystrophic and progeroid syndromes. Among these are dilated cardiomyopathy and two forms of muscular dystrophy (limb-girdle and Emery-Dreifuss), which are modeled in lmna (-/-) mice and mice engineered to express human disease mutations. Our recent study demonstrates that cardiac and skeletal muscle pathology in lmna (-/-) mice can be attributed to elevated MTORC1 signaling leading to impairment of autophagic flux. An accompanying paper from another laboratory shows similar impairments in mice engineered to express the LMNA H222P associated with dilated cardiomyopathy in humans and also in left ventricular tissue from human subjects. MTORC1 inhibition with rapalogs restores autophagic flux and improves cardiac function in both mouse models, and extends survival in the lmna (-/-) mice. These findings elaborate a potential treatment option for dilated cardiomyopathy and muscular dystrophy associated with LMNA mutation and supplement growing evidence linking impaired autophagy to human disease.
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Affiliation(s)
- Fresnida J Ramos
- Department of Pathology, University of Washington, Seattle, WA, USA
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11
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Starling N, Vázquez-Mazón F, Cunningham D, Chau I, Tabernero J, Ramos FJ, Iveson TJ, Saunders MP, Aranda E, Countouriotis AM, Ruiz-Garcia A, Wei G, Tursi JM, Guillen-Ponce C, Carrato A. A phase I study of sunitinib in combination with FOLFIRI in patients with untreated metastatic colorectal cancer. Ann Oncol 2012; 23:119-127. [PMID: 21447616 DOI: 10.1093/annonc/mdr046] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND This study evaluated the maximum tolerated dose (MTD) of sunitinib, a multitargeted tyrosine kinase inhibitor, combined with FOLFIRI (irinotecan 180 mg/m2 given over 90 min i.v. and l-leucovorin 200 mg/m2 given over 120 min on day 1, followed by 5-FU 400 mg/m2 bolus and then 2400 mg/m2 infused over 46 h) in untreated metastatic colorectal cancer (mCRC). PATIENTS AND METHODS In this multicentre, phase I, open-label, dose-finding trial, FOLFIRI was administered every 2 weeks. Two sunitinib regimens were explored: Schedule 4/2 (4 weeks on, 2 weeks off; 37.5 and 50 mg/day) and continuous daily dosing (CDD; 37.5 and 25 mg/day). Dose-limiting toxic toxicities (DLTs) were evaluated during weeks 1-6. Efficacy was a secondary objective. RESULTS Thirty-seven patients were enrolled. The 37.5 mg/day Schedule 4/2 cohort had zero of six DLTs, was expanded by 15 patients and declared the MTD. The MTD was exceeded at all other sunitinib doses and schedules; DLTs included febrile neutropenia (n=1), grade 4 neutropenia (n=4) and grade 3 deep vein thrombosis with grade 4 neutropenia (n=1). At the MTD, non-haematologic grade 3/4 adverse events with a frequency of >10% were diarrhoea, vomiting and lethargy, and the objective response rate was 57.9% (95% confidence interval 33.5-79.7). CONCLUSIONS The MTD of sunitinib combined with FOLFIRI in chemotherapy-naive mCRC was 37.5 mg/day on Schedule 4/2. CDD of sunitinib at 37.5 or 25 mg/day plus FOLFIRI was not feasible.
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Affiliation(s)
- N Starling
- Department of Medicine, Royal Marsden Hospital, NHS Foundation Trust, London and Sutton, UK
| | - F Vázquez-Mazón
- Medical Oncology Department, Elche University Hospital, Elche
| | - D Cunningham
- Department of Medicine, Royal Marsden Hospital, NHS Foundation Trust, London and Sutton, UK.
| | - I Chau
- Department of Medicine, Royal Marsden Hospital, NHS Foundation Trust, London and Sutton, UK
| | - J Tabernero
- Department of Medical Oncology, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - F J Ramos
- Department of Medical Oncology, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - T J Iveson
- Department of Medical Oncology, Southampton Oncology Centre, Southampton General Hospital, Southampton
| | - M P Saunders
- Department of Radiotherapy and Clinical Oncology, Christie Hospital, Manchester, UK
| | - E Aranda
- Department of Medical Oncology, Hospital Universitario Reina Sofia, Cordoba, Spain
| | | | | | - G Wei
- Pfizer Oncology, Oncology Statistics, La Jolla, USA
| | - J M Tursi
- Pfizer Italia Srl, Clinical Development Oncology, Milan, Italy
| | - C Guillen-Ponce
- Medical Oncology Department, Ramon y Cajal University Hospital, Madrid, Spain
| | - A Carrato
- Medical Oncology Department, Ramon y Cajal University Hospital, Madrid, Spain
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Mehta R, Chandler-Brown D, Ramos FJ, Shamieh LS, Kaeberlein M. Regulation of mRNA translation as a conserved mechanism of longevity control. Adv Exp Med Biol 2010; 694:14-29. [PMID: 20886753 DOI: 10.1007/978-1-4419-7002-2_2] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Appropriate regulation of mRNA translation is essential for growth and survival and the pathways that regulate mRNA translation have been highly conserved throughout eukaryotic evolution. Translation is controlled by a complex set of mechanisms acting at multiple levels, ranging from global protein synthesis to individual mRNAs. Recently, several mutations that perturb regulation of mRNA translation have also been found to increase longevity in three model organisms: the buddingyeast Saccharomyces cerevisiae, the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster. Many of these translation control factors can be mapped to a single pathway downstream of the nutrient responsive target of rapamycin (TOR) kinase. In this chapter, we will review the data suggesting that mRNA translation is an evolutionarily conserved modifier of longevity and discuss potential mechanisms by which mRNA translation could influence aging and age-associated disease in different species.
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Affiliation(s)
- Ranjana Mehta
- Department of Pathology, University of Washington, Seattle, Washington, USA
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13
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Wang C, Xin X, Xiang R, Ramos FJ, Liu M, Lee HJ, Chen H, Mao X, Kikani CK, Liu F, Dong LQ. Yin-Yang regulation of adiponectin signaling by APPL isoforms in muscle cells. J Biol Chem 2009; 284:31608-15. [PMID: 19661063 DOI: 10.1074/jbc.m109.010355] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
APPL1 is a newly identified adiponectin receptor-binding protein that positively mediates adiponectin signaling in cells. Here we report that APPL2, an isoform of APPL1 that forms a dimer with APPL1, can interacts with both AdipoR1 and AdipoR2 and acts as a negative regulator of adiponectin signaling in muscle cells. Overexpression of APPL2 inhibits the interaction between APPL1 and AdipoR1, leading to down-regulation of adiponectin signaling in C2C12 myotubes. In contrast, suppressing APPL2 expression by RNAi significantly enhances adiponectin-stimulated glucose uptake and fatty acid oxidation. In addition to targeting directly to and competing with APPL1 in binding with the adiponectin receptors, APPL2 also suppresses adiponectin and insulin signaling by sequestrating APPL1 from these two pathways. In addition to adiponectin, metformin also induces APPL1-APPL2 dissociation. Taken together, our results reveal that APPL isoforms function as an integrated Yin-Yang regulator of adiponectin signaling and mediate the cross-talk between adiponectin and insulin signaling pathways in muscle cells.
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Affiliation(s)
- Changhua Wang
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA
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Mehta R, Steinkraus KA, Sutphin GL, Ramos FJ, Shamieh LS, Huh A, Davis C, Chandler-Brown D, Kaeberlein M. Proteasomal regulation of the hypoxic response modulates aging in C. elegans. Science 2009; 324:1196-8. [PMID: 19372390 PMCID: PMC2737476 DOI: 10.1126/science.1173507] [Citation(s) in RCA: 185] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Caenorhabditis elegans von Hippel-Lindau tumor suppressor homolog VHL-1 is a cullin E3 ubiquitin ligase that negatively regulates the hypoxic response by promoting ubiquitination and degradation of the hypoxic response transcription factor HIF-1. Here, we report that loss of VHL-1 significantly increased life span and enhanced resistance to polyglutamine and beta-amyloid toxicity. Deletion of HIF-1 was epistatic to VHL-1, indicating that HIF-1 acts downstream of VHL-1 to modulate aging and proteotoxicity. VHL-1 and HIF-1 control longevity by a mechanism distinct from both dietary restriction and insulin-like signaling. These findings define VHL-1 and the hypoxic response as an alternative longevity and protein homeostasis pathway.
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Affiliation(s)
- Ranjana Mehta
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
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15
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Wang L, Balas B, Christ-Roberts CY, Kim RY, Ramos FJ, Kikani CK, Li C, Deng C, Reyna S, Musi N, Dong LQ, DeFronzo RA, Liu F. Peripheral disruption of the Grb10 gene enhances insulin signaling and sensitivity in vivo. Mol Cell Biol 2007; 27:6497-505. [PMID: 17620412 PMCID: PMC2099625 DOI: 10.1128/mcb.00679-07] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Grb10 is a pleckstrin homology and Src homology 2 domain-containing protein that interacts with a number of phosphorylated receptor tyrosine kinases, including the insulin receptor. In mice, Grb10 gene expression is imprinted with maternal expression in all tissues except the brain. While the interaction between Grb10 and the insulin receptor has been extensively investigated in cultured cells, whether this adaptor protein plays a positive or negative role in insulin signaling and action remains controversial. In order to investigate the in vivo role of Grb10 in insulin signaling and action in the periphery, we generated Grb10 knockout mice by the gene trap technique and analyzed mice with maternal inheritance of the knockout allele. Disruption of Grb10 gene expression in peripheral tissues had no significant effect on fasting glucose and insulin levels. On the other hand, peripheral-tissue-specific knockout of Grb10 led to significant overgrowth of the mice, consistent with a role for endogenous Grb10 as a growth suppressor. Loss of Grb10 expression in insulin target tissues, such as skeletal muscle and fat, resulted in enhanced insulin-stimulated Akt and mitogen-activated protein kinase phosphorylation. Hyperinsulinemic-euglycemic clamp studies revealed that disruption of Grb10 gene expression in peripheral tissues led to increased insulin sensitivity. Taken together, our results provide strong evidence that Grb10 is a negative regulator of insulin signaling and action in vivo.
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Affiliation(s)
- Lixin Wang
- Department of Pharmacology, UTHSCSA, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Olivares JL, Bueno I, Gallati S, Ramos FJ. Late-onset treatment in Menkes disease: is there a correlation between genotype and response to therapy? Clin Genet 2006; 69:363-6. [PMID: 16630173 DOI: 10.1111/j.1399-0004.2006.00596.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Ramos FJ, Langlais PR, Hu D, Dong LQ, Liu F. Grb10 mediates insulin-stimulated degradation of the insulin receptor: a mechanism of negative regulation. Am J Physiol Endocrinol Metab 2006; 290:E1262-6. [PMID: 16434550 DOI: 10.1152/ajpendo.00609.2005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Growth factor receptor-bound protein 10 (Grb10) is an adapter protein that interacts with a number of tyrosine-phosphorylated growth factor receptors, including the insulin receptor (IR). To investigate the role of Grb10 in insulin signaling, we generated cell lines in which the expression levels of Grb10 are either overexpressed by stable transfection or suppressed by RNA interference. We found that suppressing endogenous Grb10 expression led to increased IR protein levels, whereas overexpression of Grb10 led to reduced IR protein levels. Altering Grb10 expression levels had no effect on the mRNA levels of IR, suggesting that the modulation occurs at the protein level. Reduced IR levels were also observed in cells with prolonged insulin treatment, and this reduction was inhibited in Grb10-deficient cells. The insulin-induced IR reduction was greatly reversed by MG-132, a proteasomal inhibitor, but not by chloroquine, a lysosomal inhibitor. IR underwent insulin-stimulated ubiquitination in cells, and this ubiquitination was inhibited in the Grb10-suppressed cell line. Together, our results suggest that, in addition to inhibiting IR kinase activity by directly binding to the IR, Grb10 also negatively regulates insulin signaling by mediating insulin-stimulated degradation of the receptor.
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Affiliation(s)
- Fresnida J Ramos
- Dept. of Pharmacology, UTHSCSA, 7703 Floyd Curl Dr., San Antonio, TX 78229, USA
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18
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Mao X, Kikani CK, Riojas RA, Langlais P, Wang L, Ramos FJ, Fang Q, Christ-Roberts CY, Hong JY, Kim RY, Liu F, Dong LQ. APPL1 binds to adiponectin receptors and mediates adiponectin signalling and function. Nat Cell Biol 2006; 8:516-23. [PMID: 16622416 DOI: 10.1038/ncb1404] [Citation(s) in RCA: 503] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Accepted: 03/17/2006] [Indexed: 02/06/2023]
Abstract
Adiponectin, also known as Acrp30, is an adipose tissue-derived hormone with anti-atherogenic, anti-diabetic and insulin sensitizing properties. Two seven-transmembrane domain-containing proteins, AdipoR1 and AdipoR2, have recently been identified as adiponectin receptors, yet signalling events downstream of these receptors remain poorly defined. By using the cytoplasmic domain of AdipoR1 as bait, we screened a yeast two-hybrid cDNA library derived from human fetal brain. This screening led to the identification of a phosphotyrosine binding domain and a pleckstrin homology domain-containing adaptor protein, APPL1 (adaptor protein containing pleckstrin homology domain, phosphotyrosine binding (PTB) domain and leucine zipper motif). APPL1 interacts with adiponectin receptors in mammalian cells and the interaction is stimulated by adiponectin. Overexpression of APPL1 increases, and suppression of APPL1 level reduces, adiponectin signalling and adiponectin-mediated downstream events (such as lipid oxidation, glucose uptake and the membrane translocation of glucose transport 4 (GLUT4)). Adiponectin stimulates the interaction between APPL1 and Rab5 (a small GTPase) interaction, leading to increased GLUT4 membrane translocation. APPL1 also acts as a critical regulator of the crosstalk between adiponectin signalling and insulin signalling pathways. These results demonstrate a key function for APPL1 in adiponectin signalling and provide a molecular mechanism for the insulin sensitizing function of adiponectin.
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Affiliation(s)
- Xuming Mao
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
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Abstract
Esophageal cancer (EC) and gastric cancer (GC) constitute a major cause of cancer deaths worldwide. Recent improvements in both surgical techniques and adjuvant/neoadjuvant radiotherapy and chemotherapy approaches have increased the survival of patients with loco-regional disease. However, most of the patients with GC or EC have advanced disease either at diagnosis or at follow-up. Despite recent advances in the treatment of advanced disease, these patients still do poorly. An emerging understanding of the molecular pathways that characterize cell growth, cell cycle, apoptosis, angiogenesis and invasion has provided novel targets in cancer therapy. In this review we describe the current status of targeted therapies in the treatment of EC and GC. These therapeutic strategies include EGFR inhibitors, antiangiogenic agents, cell cycle inhibitors, apoptosis promoters and matrix metalloproteinases inhibitors. The emerging data from the clinical development of these compounds has provided novel opportunities in the treatment of EC and GC that will probably translate into efficacy advantage in the treatment of these common malignancies.
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Affiliation(s)
- J Tabernero
- Medical Oncology Department, Vall d'Hebron University Hospital, Barcelona, Spain.
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20
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Langlais P, Dong LQ, Ramos FJ, Hu D, Li Y, Quon MJ, Liu F. Negative regulation of insulin-stimulated mitogen-activated protein kinase signaling by Grb10. Mol Endocrinol 2003; 18:350-8. [PMID: 14615605 DOI: 10.1210/me.2003-0117] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Grb10 is a Pleckstrin homology and Src homology 2 (SH2) domain-containing protein that binds to the tyrosine-phosphorylated insulin receptor in response to insulin stimulation. Loss of Grb10 function in mice results in fetal and placental overgrowth; however, the molecular mechanism remains unknown. In the present study, we show that overexpression of Grb10 in Chinese hamster ovary cells expressing the insulin receptor or in 3T3-L1 adipocytes reduced insulin-stimulated phosphorylation of MAPK. Overexpression of Grb10 in rat primary adipocytes also inhibited insulin-stimulated phosphorylation of the MAPK downstream substrate Elk1. To determine the mechanism by which Grb10 inhibited insulin-stimulated MAPK signaling, we examined whether Grb10 affects the phosphorylation of MAPK upstream signaling components. We found that overexpression of Grb10 inhibited the insulin-stimulated phosphorylation of Shc, a positive regulator of the MAPK signaling pathway. The inhibitory effect was diminished when the SH2 domain of Grb10 was deleted. The negative role of Grb10 in insulin signaling was established by suppression of endogenous Grb10 by RNA interference in HeLa cells overexpressing the insulin receptor, which enhanced insulin-stimulated phosphorylation of MAPK, Shc, and Akt. Taken together, our findings suggest that Grb10 functions as a negative regulator in the insulin-stimulated MAPK signaling pathway. In addition, the inhibitory effect of Grb10 on the MAPK pathway is most likely due to a direct block of insulin-stimulated Shc tyrosine phosphorylation.
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Affiliation(s)
- Paul Langlais
- Department of Biochemistry, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, Texas 78229, USA
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21
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Wick MJ, Ramos FJ, Chen H, Quon MJ, Dong LQ, Liu F. Mouse 3-phosphoinositide-dependent protein kinase-1 undergoes dimerization and trans-phosphorylation in the activation loop. J Biol Chem 2003; 278:42913-9. [PMID: 12923190 DOI: 10.1074/jbc.m304172200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of mouse 3-phosphoinositide-dependent protein kinase-1 (mPDK1) requires phosphorylation at a conserved serine residue, Ser244, in the activation loop. However, the mechanism by which mPDK1 is phosphorylated at this site remains unclear. We have found that kinase-defective mPDK1 (mPDK1KD), but not a kinase-defective mPDK1 in which Ser244 was replaced with alanine (mPDK1KD/S244A), is significantly phosphorylated in intact cells and is a direct substrate of wild-type mPDK1 fused to the yellow fluorescence protein. Phosphoamino acid analysis and phosphopeptide mapping studies revealed that mPDK1 trans-autophosphorylation occurred mainly on Ser244. On the other hand, Ser399 and Thr516, two recently identified autophosphorylation sites of mPDK1, are phosphorylated primarily through a cis mechanism. In vivo labeling studies revealed that insulin stimulated both mPDK1KD and mPDK1KD/S244A phosphorylation in Chinese hamster ovary cells overexpressing the insulin receptor. However, Western blot analysis using a phosphospecific antibody revealed no increase in insulin-stimulated phosphorylation of Ser244 in these cells overexpressing mPDK1. mPDK1 undergoes dimerization in cells and this self-association is enhanced by kinase inactivation. Deletion of the extreme C terminus disrupts mPDK1 dimerization and Ser244 trans-phosphorylation, suggesting that dimerization is important for mPDK1 trans-phosphorylation. Taken together, our results show that mPDK1 autophosphorylation occurs at multiple sites through both cis and trans mechanisms and suggest that dimerization and trans-phosphorylation may serve as mechanisms to regulate PDK1 activity in cells.
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Affiliation(s)
- Michael J Wick
- Departments of Pharmacology, Biochemistry, and Cellular & Structural Biology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA
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Wick KR, Werner ED, Langlais P, Ramos FJ, Dong LQ, Shoelson SE, Liu F. Grb10 inhibits insulin-stimulated insulin receptor substrate (IRS)-phosphatidylinositol 3-kinase/Akt signaling pathway by disrupting the association of IRS-1/IRS-2 with the insulin receptor. J Biol Chem 2003; 278:8460-7. [PMID: 12493740 DOI: 10.1074/jbc.m208518200] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Grb10 has been proposed to inhibit or activate insulin signaling, depending on cellular context. We have investigated the mechanism by which full-length hGrb10gamma inhibits signaling through the insulin receptor substrate (IRS) proteins. Overexpression of hGrb10gamma in CHO/IR cells and in differentiated adipocytes significantly reduced insulin-stimulated tyrosine phosphorylation of IRS-1 and IRS-2. Inhibition occurred rapidly and was sustained for 60 min during insulin stimulation. In agreement with inhibited signaling through the IRS/PI 3-kinase pathway, we found hGrb10gamma to both delay and reduce phosphorylation of Akt at Thr(308) and Ser(473) in response to insulin stimulation. Decreased phosphorylation of IRS-1/2 may arise from impaired catalytic activity of the receptor, since hGrb10gamma directly associates with the IR kinase regulatory loop. However, yeast tri-hybrid studies indicated that full-length Grb10 blocks association between IRS proteins and IR, and that this requires the SH2 domain of Grb10. In cells, hGrb10gamma inhibited insulin-stimulated IRS-1 tyrosine phosphorylation in a dose-dependent manner, but did not affect IR catalytic activity toward Tyr(972) in the juxtamembrane region and Tyr(1158/1162/1163) in the regulatory domain. We conclude that binding of hGrb10gamma to IR decreases signaling through the IRS/PI 3-kinase/AKT pathway by physically blocking IRS access to IR.
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Affiliation(s)
- KeriLyn R Wick
- Department of Pharmacology, The University of Texas Health Science Center, San Antonio 78229, USA
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Dong LQ, Ramos FJ, Wick MJ, Lim MA, Guo Z, Strong R, Richardson A, Liu F. Cloning and characterization of a testis and brain-specific isoform of mouse 3'-phosphoinositide-dependent protein kinase-1, mPDK-1 beta. Biochem Biophys Res Commun 2002; 294:136-44. [PMID: 12054753 DOI: 10.1016/s0006-291x(02)00449-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
3'-Phosphoinositide-dependent protein kinase-1 (PDK-1) phosphorylates and activates members of the protein kinase AGC family and plays a key role in receptor tyrosine kinase signaling. Here we report the cloning and characterization of a splice variant of mouse PDK-1, mPDK-1 beta. The cDNA encoding mPDK-1 beta contains two alternative start codons and translation from these start codons generates proteins that are, respectively, 27 or 51 amino acid residues shorter at the amino-terminus than the previously identified PDK-1 isolated from mouse liver (now renamed mPDK-1 alpha) [J. Biol. Chem. 274 (1999) 8117]. Analysis of mouse tissues shows that mPDK-1 beta is highly expressed in the testis and various functional regions of the brain. Expression of this isoform is increased in the brain of aged mice. Both mPDK-1 alpha and mPDK-1 beta are autophosphorylated at both serine and threonine residues in vitro and showed similar levels of tyrosine phosphorylation when co-expressed with either constitutively active Src or Fyn tyrosine kinases in cells. However, the mPDK-1 isoforms showed significant differences in their response to pervanadate- or insulin plus vanadate-stimulated tyrosine phosphorylation. Taken together, our findings suggest that the two PDK-1 isoforms may be differentially regulated in cells. The specific expression of mPDK-1 beta in mouse testis and brains of aged mice also suggests potential involvement of this kinase in regulating animal spermatogenesis and aging.
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Affiliation(s)
- Lily Q Dong
- Department of Pharmacology, The University of Texas Health Science Center, San Antonio, TX 78229, USA.
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Balemans W, Ebeling M, Patel N, Van Hul E, Olson P, Dioszegi M, Lacza C, Wuyts W, Van Den Ende J, Willems P, Paes-Alves AF, Hill S, Bueno M, Ramos FJ, Tacconi P, Dikkers FG, Stratakis C, Lindpaintner K, Vickery B, Foernzler D, Van Hul W. Increased bone density in sclerosteosis is due to the deficiency of a novel secreted protein (SOST). Hum Mol Genet 2001; 10:537-43. [PMID: 11181578 DOI: 10.1093/hmg/10.5.537] [Citation(s) in RCA: 805] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sclerosteosis is a progressive sclerosing bone dysplasia with an autosomal recessive mode of inheritance. Radiologically, it is characterized by a generalized hyperostosis and sclerosis leading to a markedly thickened and sclerotic skull, with mandible, ribs, clavicles and all long bones also being affected. Due to narrowing of the foramina of the cranial nerves, facial nerve palsy, hearing loss and atrophy of the optic nerves can occur. Sclerosteosis is clinically and radiologically very similar to van Buchem disease, mainly differentiated by hand malformations and a large stature in sclerosteosis patients. By linkage analysis in one extended van Buchem family and two consanguineous sclerosteosis families we previously mapped both disease genes to the same chromosomal 17q12-q21 region, supporting the hypothesis that both conditions are caused by mutations in the same gene. After reducing the disease critical region to approximately 1 Mb, we used the positional cloning strategy to identify the SOST gene, which is mutated in sclerosteosis patients. This new gene encodes a protein with a signal peptide for secretion and a cysteine-knot motif. Two nonsense mutations and one splice site mutation were identified in sclerosteosis patients, but no mutations were found in a fourth sclerosteosis patient nor in the patients from the van Buchem family. As the three disease-causing mutations lead to loss of function of the SOST protein resulting in the formation of massive amounts of normal bone throughout life, the physiological role of SOST is most likely the suppression of bone formation. Therefore, this gene might become an important tool in the development of therapeutic strategies for osteoporosis.
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Affiliation(s)
- W Balemans
- Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
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Wick MJ, Dong LQ, Riojas RA, Ramos FJ, Liu F. Mechanism of phosphorylation of protein kinase B/Akt by a constitutively active 3-phosphoinositide-dependent protein kinase-1. J Biol Chem 2000; 275:40400-6. [PMID: 11006271 DOI: 10.1074/jbc.m003937200] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphorylation of Thr(308) in the activation loop and Ser(473) at the carboxyl terminus is essential for protein kinase B (PKB/Akt) activation. However, the biochemical mechanism of the phosphorylation remains to be characterized. Here we show that expression of a constitutively active mutant of mouse 3-phosphoinositide-dependent protein kinase-1 (PDK1(A280V)) in Chinese hamster ovary cells overexpressing the insulin receptor was sufficient to induce PKB phosphorylation at Thr(308) to approximately the same extent as insulin stimulation. Phosphorylation of PKB by PDK1(A280V) was not affected by treatment of cells with inhibitors of phosphatidylinositol 3-kinase or by deletion of the pleckstrin homology (PH) domain of PKB. C(2)-ceramide, a cell-permeable, indirect inhibitor of PKB phosphorylation, did not inhibit PDK1(A280V)-catalyzed PKB phosphorylation in cells and had no effect on PDK1 activity in vitro. On the other hand, co-expression of full-length protein kinase C-related kinase-1 (PRK1/PKN) or 2 (PRK2) inhibited PDK1(A280V)-mediated PKB phosphorylation. Replacing alanine at position 280 with valine or deletion of the PH domain enhanced PDK1 autophosphorylation in vitro. However, deletion of the PH domain of PDK1(A280V) significantly reduced PDK1(A280V)-mediated phosphorylation of PKB in cells. In resting cells, PDK1(A280V) localized in the cytosol and at the plasma membrane. However, PDK1(A280V) lacking the PH domain localized predominantly in the cytosol. Taken together, our findings suggest that the wild-type PDK1 may not be constitutively active in cells. In addition, activation of PDK1 is sufficient to phosphorylate PKB at Thr(308) in the cytosol. Furthermore, the PH domain of PDK1 may play both positive and negative roles in regulating the in vivo function of the enzyme. Finally, unlike the carboxyl-terminal fragment of PRK2, which has been shown to bind PDK1 and allow the enzyme to phosphorylate PKB at both Thr(308) and Ser(473), full-length PRK2 and its related kinase PRK1/PKN may both play negative roles in PKB-mediated downstream biological events.
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Affiliation(s)
- M J Wick
- Departments of Pharmacology and Biochemistry, The University of Texas Health Science Center, San Antonio, Texas 78229, USA
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Olivares JL, Ramos FJ, Carapeto FJ, Bueno M. Epidermal naevus syndrome and hypophosphataemic rickets: description of a patient with central nervous system anomalies and review of the literature. Eur J Pediatr 1999; 158:103-7. [PMID: 10048604 DOI: 10.1007/s004310051027] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The epidermal naevus syndrome (ENS) is a rare dermatological condition consisting of congenital epidermal nevi associated with anomalies in the central nervous system, bones, eyes, hear or genito-urinary system. We report a new case of ENS associated with hypophosphataemic rickets. The girl was born with a mixed-type epidermal naevus and skeletal anomalies. Hypophosphataemic rickets was diagnosed at the age of 2.5 years. At 14 years of age. MRI of the head demonstrated right brain hypotrophy, a left temporal arachnoid cyst and asymmetric lateral ventricles. We reviewed the literature and found 13 reported cases of ENS associated with hypophosphataemic rickets. Conclusion We report a further patient with epidermal naevus syndrome and hypophosphataemic rickets, followed from birth to the age of 15 years, who had structural central nervous system anomalies with normal intellectual functioning. A comprehensive neurological work up is recommended in patients with epidermal naevus syndrome.
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Affiliation(s)
- J L Olivares
- Departamento de Pediatría, Facultad de Medicina, Universidad de Zaragoza, Spain.
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28
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Abstract
Osteopathia striata with cranial sclerosis (OS-CS) is a bone dysplasia characterized by longitudinal striations of the long bones and sclerosis of the craniofacial bones. Affected patients show macrocephaly, ocular hypertelorism, frontal bossing, broad nasal bridge and abnormalities of the palate. Anomalies such as hearing loss, congenital heart defect, vertebral anomalies and mental impairment have also been reported. Pedigree analysis has suggested an autosomal dominant inheritance, but a recent report of a family with significantly more affected males than females suggested the possibility of X-linked inheritance. Here we describe a new family with OS-CS (the twelfth in the literature) with four affected individuals (two males and two females) spanning three generations. The affected male in the third generation was stillborn with multiple congenital anomalies, whereas the other three affected individuals had mild features. This family may represent another example of X-linked OS-CS where the mutated gene(s) is more severe in males.
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Affiliation(s)
- A L Bueno
- Servicio de Traumatología y Cirugía Ortopédica, Hospital Clínico Universitario Lozano Blesa, Universidad de Zaragoza, Spain
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Ramos FJ, Kaplan BS, Bellah RD, Zackai EH, Kaplan P. Further evidence that the Hajdu-Cheney syndrome and the "serpentine fibula-polycystic kidney syndrome" are a single entity. Am J Med Genet 1998; 78:474-81. [PMID: 9714016 DOI: 10.1002/(sici)1096-8628(19980806)78:5<474::aid-ajmg14>3.0.co;2-c] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Hajdu-Cheney syndrome (HCS) is a rare autosomal dominant disorder. It comprises a coarse face, short neck, hirsutism, joint laxity, and normal intelligence. Bone dysplasias, include acro-osteolysis, bathrocephaly, and vertebral anomalies. In 1988, Exner [1988: Eur J Pediatr 147:544-546] coined the term "serpentine fibula-polycystic kidney syndrome" (SFPKS) when he reported on a girl with short stature, unusual facial appearance, polycystic kidneys, and elongated curved fibulae. He postulated that it was a new entity different from the Melnick-Needles syndrome. Since his report, five similar cases have been published. Similarities between both HCS and SFPKS were noticed first by us and then by other authors. In this report we show that many clinical and radiological characteristics are shared by the HCS and the SFPKS and hypothesize that they represent a single entity with a variable degree of expression.
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Affiliation(s)
- F J Ramos
- Sección de Genética, Departamento de Pediatría, Facultad de Medicina, Universidad de Zaragoza, Spain.
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30
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Clavel A, Olivares JL, Fleta J, Castillo J, Varea M, Ramos FJ, Arnal AC, Quílez J. Seasonality of cryptosporidiosis in children. Eur J Clin Microbiol Infect Dis 1996; 15:77-9. [PMID: 8641309 DOI: 10.1007/bf01586190] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The seasonal distribution of cryptosporidiosis in children in Aragón, a region in northeastern Spain, was determined. Over a period of six years (October 1988 to September 1994), 10,034 stool samples from 4,508 children with gastrointestinal symptoms were analyzed for this purpose. The age of the patients ranged from 1 month to 14 years. Cryptosporidium oocysts were identified in 87 (1.93%) patients. Prevalence was highest (6.20%) in children aged 1 to 3 years old. The prevalence was significantly higher in the autumn-winter period (October to March) than in the spring-summer period (April to September) in the whole population (2.41% vs. 1.35%, p = 0.010) and in the 1- to 3-year-old age group (8.44% vs. 3.20%, p = 0.002), but not in the other age groups. A possible relationship of this pattern to attendance at child care centres is suggested.
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Affiliation(s)
- A Clavel
- Departamento de Microbiología, Medicina Preventiva y Salud Pública, Hospital Clínico Universitario, Facultad de Medicina, Universidad de Zaragoza, Spain
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31
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Ramos FJ, del Cañizo MC, Nieto MJ, Corral M. [Current clinical use of hematopoietic growth factors]. Sangre (Barc) 1995; 40:311-25. [PMID: 7482121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- F J Ramos
- Servicio de Hematología. Hospital de León
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Bueno M, Oliván G, Jiménez A, Garagorri JM, Sarría A, Bueno AL, Bueno M, Ramos FJ. Sclerosteosis in a Spanish male: first report in a person of Mediterranean origin. J Med Genet 1994; 31:976-7. [PMID: 7891385 PMCID: PMC1016704 DOI: 10.1136/jmg.31.12.976] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We report the first observation of sclerosteosis in Spain. To the best of our knowledge, this is the first case of sclerosteosis in a person of Mediterranean origin with no known Dutch ancestors. He has the characteristic phenotype of the disease with right facial nerve palsy and syndactyly and the typical radiological features, including generalised bone sclerosis and cortical widening of the tubular bones.
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Affiliation(s)
- M Bueno
- Departmento de Traumatología, Facultad de Medicina, Hospital Clínico Universitario, Lozano Blesa, Universidad de Zaragoza, Spain
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Ramos FJ, Sandoval V, Rodríguez JA, Moro MJ. [The paradox of G-CSF]. Med Clin (Barc) 1994; 102:718-9. [PMID: 7518024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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34
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Ramos FJ, Eunpu DL, Finucane B, Pfendner EG. Direct DNA testing for fragile X syndrome. Am J Dis Child 1993; 147:1231-5. [PMID: 7901988 DOI: 10.1001/archpedi.1993.02160350105016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The recent identification of an abnormally amplified trinucleotide (cytosine guanine guanine) repeat in the fragile X gene (FMR-1) of males with fragile X syndrome and their carrier mothers allows the study of the mutation in individuals at risk. In this report, data on 396 patients and 35 normal controls are reported. Included in this sample are patients with no known family history of fragile X syndrome or mental retardation for whom the risks of fragile X syndrome are unclear. All 39 cytogenetically positive affected males and six females had the full mutation, as represented by a restriction fragment size increase (delta) of 500 base pairs (bp) or more within the cytosine guanine guanine repeat-bearing fragment of the FMR-1 gene; and all 16 of the normal obligate carrier females bore the premutation, as demonstrated by a delta of 100 to 500 bp. Of 124 patients (62 males and 62 females) with a family history of fragile X syndrome, five (8%) of the males and 25 (40%) of the females had the premutation. Five (2.2%) of the 231 mentally impaired patients with no confirmed family history of fragile X syndrome were found to have the full mutation. Twelve (33%) of 36 mentally impaired males and one (20%) of five females with unknown family history were found to carry an amplified cytosine guanine guanine repeat. Using this technique, we also reevaluated risk assessments previously generated by linkage analysis and unambiguously determined the carrier status of individual family members.
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Affiliation(s)
- F J Ramos
- Department of Pediatrics, Albert Einstein Medical Center, Philadelphia, PA
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Reid CS, McMorrow LE, McDonald-McGinn DM, Grace KJ, Ramos FJ, Zackai EH, Cohen MM, Jabs EW. Saethre-Chotzen syndrome with familial translocation at chromosome 7p22. Am J Med Genet 1993; 47:637-9. [PMID: 8266989 DOI: 10.1002/ajmg.1320470511] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Chromosome analysis of a male infant and his mother with Saethre-Chotzen syndrome demonstrated an apparently balanced translocation, t(2;7)(p23;p22). This association lends support to localization of the gene for Saethre-Chotzen syndrome to the 7p2 region and supports further involvement of gene(s) in the 7p22 region.
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Affiliation(s)
- C S Reid
- Division of Pediatric Genetics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Camden
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36
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Ramos FJ, McDonald-McGinn DM, Emanuel BS, Zackai EH. Tricho-rhino-phalangeal syndrome type II (Langer-Giedion) with persistent cloaca and prune belly sequence in a girl with 8q interstitial deletion. Am J Med Genet 1992; 44:790-4. [PMID: 1481848 DOI: 10.1002/ajmg.1320440614] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A patient with the diagnosis of Langer-Giedion syndrome (tricho-rhino-phalangeal syndrome type II) and interstitial 8q deletion was also noted to have persistent cloaca and prune belly sequence. This is the first report of this association. If it postulated that these latter embryonic defects may be due to the chromosome abnormality, supporting the definition of contiguous gene syndrome.
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Affiliation(s)
- F J Ramos
- Division of Clinical Genetics, Children's Hospital of Philadelphia, Pennsylvania 19104
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Riggins GJ, Sherman SL, Oostra BA, Sutcliffe JS, Feitell D, Nelson DL, van Oost BA, Smits AP, Ramos FJ, Pfendner E. Characterization of a highly polymorphic dinucleotide repeat 150 KB proximal to the fragile X site. Am J Med Genet 1992; 43:237-43. [PMID: 1605197 DOI: 10.1002/ajmg.1320430138] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Fragile X [fra (X)] syndrome is a frequently encountered form of mental retardation and is inherited as an X-linked semi-dominant trait with reduced penetrance. We report here the characterization of a highly polymorphic dinucleotide repeat, DXS 548, which is approximately 150 kb proximal to the fra(X) site and the associated FMR-1 gene. DXS 548 is tightly linked to the fra (X) syndrome locus (FRAXA) without recombination (LOD = 9.07 with q of 0) in selected families with crossovers between FRAXA and very closely linked flanking markers. This dinucleotide repeat could be useful in determining the parental origin of a new fra (X) mutations and evaluating the role of FMR-1 in X-linked non-specific mental retardation.
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Affiliation(s)
- G J Riggins
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
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38
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Ramos FJ, Emanuel BS, Spinner NB. Frequency of the common fragile site at Xq27.2 under conditions of thymidylate stress: implications for cytogenetic diagnosis of the fragile-X syndrome. Am J Med Genet 1992; 42:835-8. [PMID: 1532475 DOI: 10.1002/ajmg.1320420618] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The distal long arm of the X chromosome contains at least 2 fragile sites, the well known rare site at Xq27.3 (FRAXA), associated with the fragile-X syndrome, and a common fragile site at Xq27.2 (FRAXD), inducible by high doses of aphidicolin. Lesions at Xq26 have also been reported in lymphocytes of mentally retarded individuals cultured under folate deprivation or thymidylate stress. This study determines the frequency of the fragile site at Xq27.2 and lesions at Xq26 in individuals referred to our laboratory to rule out the fragile-X syndrome and in control individuals using our routine culture system for the diagnosis of the syndrome. FRAXD was expressed in 1/20 (5%) individuals in each of the study groups, in 1-2% of cells. Lesions at Xq26 were found in 1-2% of the lymphocytes of 5/166 (3%) patients referred for fragile-X analysis who were FRAXA negative, and in 1% of cells of 1/20 (5%) control individuals. We conclude (1) the fragile site at Xq27.2 can be demonstrated in normal individuals under conditions of thymidylate stress routinely used for cytogenetic diagnosis of the fragile-X syndrome, (2) this fragile site is present at low levels (1-2%) in all individuals who express it and, therefore, its expression is unlikely to cause false positive diagnoses of the syndrome, (3) lesions at Xq26 are also seen at low levels in lymphocytes of individuals without the syndrome, and (4) accurate differentiation of the rare site at Xq27.3 from other distal Xq fragile sites or lesions will lead to avoidance of unnecessary repeat studies.
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Affiliation(s)
- F J Ramos
- Department of Human Genetics and Molecular Biology, Children's Hospital of Philadelphia, Pennsylvania 19104
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Ramos FJ, Gomez-Martino JR, Fernandez-Rojo FP, Suarez D. Proteinaceous lymphadenopathy and the kidney. Arch Pathol Lab Med 1992; 116:8-9. [PMID: 1734837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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40
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Affiliation(s)
- F J Ramos
- Hospital General Rio Carrión, Palencia, Spain
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Ramos FJ. [Fragile X syndrome: what do we know today?]. An Esp Pediatr 1989; 31:417-9. [PMID: 2575879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- F J Ramos
- Department of Pediatric, Albert Einstein Medical Center, Philadelphia
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Fleta J, Sarria A, Villagrasa J, Usón A, Ramos FJ, Bueno M, Calatayud V. Computed tomography in the diagnosis of brain hydatidosis in children. Acta Paediatr Scand 1987; 76:835-6. [PMID: 3661187 DOI: 10.1111/j.1651-2227.1987.tb10573.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- J Fleta
- Departamento de Pediatría, Facultad de Medicina, Hospital Clínico Universitario, Zaragoza, Spain
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López-Fernández MF, López-Berges C, Martín R, Pardo A, Ramos FJ, Batlle J. Abnormal structure of von Willebrand factor in myeloproliferative syndrome is associated to either thrombotic or bleeding diathesis. Thromb Haemost 1987; 58:753-7. [PMID: 3499682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The multimeric and subunit patterns of plasma von Willebrand factor (vWF) were analyzed in eight patients with myeloproliferative syndrome (MS) in order to investigate the possible existence of heterogeneity in the "in vivo" proteolytic cleavage of the protein, previously observed in this entity. Six patients lacked large vWF multimers, five of them having normal bleeding times (BT) and clinically documented episodes of thrombotic origin, whereas one patient had long BT and bleeding symptoms. Seven patients showed a relative increase in the 176 kDa subunit fragment while the 189 kDa polypeptide was increased in only one. In addition, another patient (and prior to any therapy) showed the presence of a new fragment of approximately 95 kDa which disappeared after Busulfan therapy. The collection of blood from these patients with proteinase inhibitors did not correct the abnormalities. The infusion of DDAVP to two patients with abnormal vWF was accompanied by: the appearance of larger vWF multimers which disappeared rapidly from plasma; an increase in the relative proportion of the satellite bands of each multimer and a further increase of the 176 kDa fragment. These data point to some heterogeneity in the vWF abnormality present in MS which may be related in part to a variable degree of proteolysis of vWF occurring "in vivo" rather than "in vitro", and which may be associated to either a thrombotic or a bleeding diathesis. They also suggest that despite the presence of abnormal, already proteolyzed vWF, DDAVP-enhanced proteolysis occurs in MS to a similar extent to what is described in normal individuals.
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Soto UL, Amador SM, Ramos FJ, Baca BE. Resistance of Pseudomonas aeruginosa to beta-lactam antibiotics. Folia Microbiol (Praha) 1987; 32:290-6. [PMID: 3117650 DOI: 10.1007/bf02877216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A series of experiments were performed with P. aeruginosa to demonstrate which of the biochemical mechanisms are responsible for the resistance to the beta-lactam antibiotics. The constitutive beta-lactamase was isolated and characterized for the strain used as type OXA whose pI was 7.1, with a molar mass of 49 kg/mol. The strain was also submitted to a series of treatments with Tris and Tris-EDTA to disrupt the outer membrane. The treated cells demonstrated a ten-fold reduction in the MIC with cloxacillin, six-fold with penicillin, and five-fold with oxacillin. At least two different biochemical mechanisms were responsible for the resistance to the beta-lactams studied which could be important in the prevalence of P. aeruginosa in nosocomial infections.
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Affiliation(s)
- U L Soto
- Departamento de Investigaciones Microbiológicas, Universidad Autónoma de Puebla, Pue., México
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Ramos FJ, Sala A, del Campo F, Nieto F, Sierra B, Adán E, Martín-Luengo C, López-Borrasca A. [The problem of multiple blood extractions]. Med Clin (Barc) 1987; 88:625-7. [PMID: 3600066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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47
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Olivares JL, Clavel A, Ramos FJ, Bueno G, Alvira A, López MJ, Lázaro A. [Cryptosporidiosis in childhood]. An Esp Pediatr 1987; 26:258-62. [PMID: 3605875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Recent application of resisting acid-fast staining techniques for parasitologic investigation has allowed cryptosporidiosis to acquire an apparent interest, mainly caused by its apparition in immunosuppressed patients, specially when they have AIDS. More recently cryptosporidiosis has been reported in immunocompetent persons whose illness, stated as acute diarrhea, is mild and self-limited. In this article we report a prospective study of a series of 36 children with cryptosporidiosis. Most of them had acute diarrhea and six were asymptomatic. Other microorganisms were found associated with Cryptosporidium in 9 cases (6 had Giardia lamblia). Period of elimination of parasite was greatly uncertain. Symptomatic treatment was performed in patients with pure cryptosporidiosis. Favourable evolution was assessed in all cases.
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Scharpf LG, Ramos FJ, Hill ID. Influence of nitrilotriacetate (NTA) on the toxicity, excretion and distribution of cadmium in female rats. Toxicol Appl Pharmacol 1972; 22:186-92. [PMID: 5048048 DOI: 10.1016/0041-008x(72)90167-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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