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1.
Trials ; 21(1): 543, 2020 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-32552907

RESUMEN

BACKGROUND: Trial oversight is important for trial governance and conduct. Patients and/or lay members of the public are increasingly included in trial oversight committees, influenced by international patient and public involvement (PPI) initiatives to improve the quality and relevance of research. However, there is a lack of guidance on how to undertake PPI in trial oversight and tokenistic PPI remains an issue. This paper explores how PPI functions in existing trial oversight committees and provides recommendations to optimise PPI in future trials. This was part of a larger study investigating the role and function of oversight committees in trials facing challenges. METHODS: Using an ethnographic study design, we observed oversight meetings of eight UK trials and conducted semi-structured interviews with members of their trial steering committees (TSCs) and trial management groups (TMGs) including public contributors, trial sponsors and funders. Thematic analysis of data was undertaken, with findings integrated to provide a multi-perspective account of how PPI functions in trial oversight. RESULTS: Eight TSC and six TMG meetings from eight trials were observed, and 66 semi-structured interviews conducted with 52 purposively sampled oversight group members, including three public contributors. PPI was reported as beneficial in trial oversight, with public members contributing a patient voice and fulfilling a patient advocacy role. However, public contributors were not always active at oversight meetings and were sometimes felt to have a tokenistic role, with trialists reporting a lack of understanding of how to undertake PPI in trial oversight. To optimise PPI in trial oversight, the following areas were highlighted: the importance of planning effective strategies to recruit public contributors; considering the level of oversight and stage(s) of trial to include PPI; support for public contributors by the trial team between and during oversight meetings. CONCLUSIONS: We present evidence-based recommendations to inform future PPI in trial oversight. Consideration should be given at trial design stage on how to recruit and involve public contributors within trial oversight, as well as support and mentorship for both public contributors and trialists (in how to undertake PPI effectively). Findings from this study further strengthen the evidence base on facilitating meaningful PPI within clinical trials.


Asunto(s)
Antropología Cultural , Participación del Paciente , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos , Proyectos de Investigación , Comités de Monitoreo de Datos de Ensayos Clínicos , Comunicación , Estudios Transversales , Humanos , Colaboración Intersectorial , Entrevistas como Asunto
2.
Cell Death Dis ; 4: e937, 2013 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-24287698

RESUMEN

Livin is a member of the inhibitor of apoptosis proteins (IAP) family of intracellular antiapoptotic proteins that act by binding and inhibiting caspases. Upon strong apoptotic stimuli, it is then specifically cleaved by caspases to produce a truncated protein (tLivin) with a paradoxical proapoptotic activity. Intriguingly, we have detected robust protein levels of Livin in normal mature bone marrow megakaryocyte (MK) and platelets. To evaluate the potential role of Livin in thrombopoiesis, we used the human BCR-ABL+ cell line, LAMA-84, and cord blood CD34+ cells to induce differentiation toward MKs. Upon differentiation, induced by phorbol myristate acetate and concurrent with increase in Livin protein expression, LAMA-84 cells formed functional platelet-like particles. Livin overexpression in CD34+ progenitor cells induced higher endoreplication in the MKs generated. Furthermore, overexpression of Livin increased the ability of both primary MKs and differentiated LAMA-84 cells to produce functional platelets. In the differentiated LAMA-84 cells, we observed accumulation of proapoptotic tLivin concomitant with increased caspase-3 activity. Downregulation of Livin with small interfering RNA in both leukemic and primary MK cells decreased their ability to produce functional platelets. We suggest that Livin has a role in thrombopoiesis by regulating the apoptotic and antiapoptotic balance in MK endoreplication and platelet production.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Plaquetas/citología , Plaquetas/metabolismo , Proteínas Inhibidoras de la Apoptosis/metabolismo , Megacariocitos/citología , Proteínas de Neoplasias/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Antígenos CD34/metabolismo , Apoptosis/genética , Apoptosis/fisiología , Diferenciación Celular/genética , Diferenciación Celular/fisiología , Línea Celular Tumoral , Humanos , Proteínas Inhibidoras de la Apoptosis/genética , Proteínas de Neoplasias/genética , ARN Interferente Pequeño/genética
3.
J Cell Mol Med ; 12(2): 479-95, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18194455

RESUMEN

Changes in protein subdomains through alternative splicing often modify protein-protein interactions, altering biological processes. A relevant example is that of the stress-induced up-regulation of the acetylcholinesterase (AChE-R) splice variant, a common response in various tissues. In germ cells of male transgenic TgR mice, AChE-R excess associates with reduced sperm differentiation and sperm counts. To explore the mechanism(s) by which AChE-R up-regulation affects spermatogenesis, we identified AChE-R's protein partners through a yeast two-hybrid screen. In meiotic spermatocytes from TgR mice, we detected AChE-R interaction with the scaffold protein RACK1 and elevated apoptosis. This correlated with reduced scavenging by RACK1 of the pro-apoptotic TAp73, an outcome compatible with the increased apoptosis. In contrast, at later stages in sperm development, AChE-R's interaction with the glycolytic enzyme enolase-alpha elevates enolase activity. In transfected cells, enforced AChE-R excess increased glucose uptake and adenosine tri-phosphate (ATP) levels. Correspondingly, TgR sperm cells display elevated ATP levels, mitochondrial hyperactivity and increased motility. In human donors' sperm, we found direct association of sperm motility with AChE-R expression. Interchanging interactions with RACK1 and enolase-alpha may hence enable AChE-R to affect both sperm differentiation and function by participating in independent cellular pathways.


Asunto(s)
Acetilcolinesterasa/metabolismo , Apoptosis , Motilidad Espermática , Espermatozoides/enzimología , Espermatozoides/fisiología , Acetilcolinesterasa/genética , Empalme Alternativo , Animales , Apoptosis/genética , Biopsia , Humanos , Inmunohistoquímica , Masculino , Ratones , Ratones Transgénicos , Modelos Biológicos , Motilidad Espermática/genética , Espermatozoides/citología , Testículo/citología , Testículo/enzimología , Testículo/metabolismo , Testículo/fisiología , Testículo/cirugía
4.
Leukemia ; 21(7): 1472-80, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17476278

RESUMEN

Hematological changes induced by various stress stimuli are accompanied by replacement of the primary acetylcholinesterase (AChE) 3' splice variant acetylcholinesterase-S (AChE-S) with the myelopoietic acetylcholinesterase-R (AChE-R) variant. To search for putative acetylcholinesterase-S interactions with hematopoietic pathways, we employed a yeast two-hybrid screen. The transcriptional co-repressor C-terminal binding protein (CtBP) was identified as a protein partner of the AChE-S C terminus. In erythroleukemic K562 cells, AChE-S displayed nuclear colocalization and physical interaction with CtBP. Furthermore, co-transfected AChE-S reduced the co-repressive effect of CtBP over the hematopoietic transcription factor, Ikaros. In transgenic mice, overexpressed human (h) AChE-S mRNA induced selective bone marrow upregulation of Ikaros while suppressing FOG, another transcriptional partner of CtBP. Transgenic bone marrow cells showed a correspondingly elevated potential for producing progenitor colonies, compared with controls, while peripheral blood showed increased erythrocyte counts as opposed to reduced platelets, granulocytes and T lymphocytes. AChE's 3' alternative splicing, and the corresponding changes in AChE-S/CtBP interactions, thus emerge as being actively involved in controlling hematopoiesis and the potential for modulating immune functions, supporting reports on malfunctioning immune reactions under impaired splice site selection.


Asunto(s)
Acetilcolinesterasa/metabolismo , Oxidorreductasas de Alcohol/metabolismo , Proteínas de Unión al ADN/metabolismo , Factor de Transcripción Ikaros/fisiología , Linfopenia/etiología , Acetilcolinesterasa/genética , Acetilcolinesterasa/fisiología , Oxidorreductasas de Alcohol/fisiología , Empalme Alternativo/fisiología , Animales , Células de la Médula Ósea , Células Cultivadas , Proteínas de Unión al ADN/fisiología , Hematopoyesis/genética , Humanos , Isoenzimas/metabolismo , Isoenzimas/fisiología , Ratones , Ratones Transgénicos , Unión Proteica , Linfocitos T
6.
Mol Med ; 7(2): 93-105, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11471550

RESUMEN

BACKGROUND: Psychological stress induces rapid and long-lasting changes in blood cell composition, implying the existence of stress-induced factors that modulate hematopoiesis. Here we report the involvement of the stress-associated "readthrough" acetylcholinesterase (AChE-R) variant, and its 26 amino acid C-terminal domain (ARP) in hematopoietic stress responses. MATERIALS AND METHODS: We studied the effects of stress, cortisol, antisense oligonucleotides to AChE, and synthetic ARP on peripheral blood cell composition and clonogenic progenitor status in mice under normal and stress conditions, and on purified CD34 cells of human origin. We employed in situ hybridization and immunocytochemical staining to monitor gene expression, and 5-bromo-2-deoxyuridine (BrdU), primary liquid cultures, and clonogenic progenitor assays to correlate AChE-R and ARP with proliferation and differentiation of hematopoietic progenitors. RESULTS: We identified two putative glucocorticoid response elements in the human ACHE gene encoding AChE. In human CD34+ hematopoietic progenitor cells, cortisol elevated AChE-R mRNA levels and promoted hematopoietic expansion. In mice, a small peptide crossreacting with anti-ARP antiserum appeared in serum following forced swim stress. Ex vivo, ARP was more effective than cortisol and equally as effective as stem cell factor in promoting expansion and differentiation of early hematopoietic progenitor cells into myeloid and megakaryocyte lineages. CONCLUSIONS: Our findings attribute a role to AChE-R and ARP in hematopoietic homeostasis following stress, and suggest the use of ARP in clinical settings where ex vivo expansion of progenitor cells is required.


Asunto(s)
Acetilcolinesterasa/química , Células Madre Hematopoyéticas/metabolismo , Péptidos/química , Animales , Antígenos CD34/biosíntesis , Bromodesoxiuridina/metabolismo , Diferenciación Celular , División Celular , Relación Dosis-Respuesta a Droga , Sangre Fetal/metabolismo , Citometría de Flujo , Humanos , Hidrocortisona/metabolismo , Hidrocortisona/farmacología , Inmunohistoquímica , Hibridación in Situ , Ratones , Oligonucleótidos Antisentido/metabolismo , Oligonucleótidos Antisentido/farmacología , Estructura Terciaria de Proteína , Regulación hacia Arriba
7.
Diabet Med ; 18(3): 242-5, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11318847

RESUMEN

AIMS: Enormous advances have been made in medical care but more people are still using herbal or alternative remedies. In chronic conditions such as diabetes patients may turn to alternative remedies that have been purported to improve glycaemic control. This study surveyed diabetic and control subjects about their use of all prescribed medication, over-the-counter supplements, and alternative medications. METHODS: Subjects were prospectively contacted in person or by telephone. Five hundred and two diabetic subjects and 201 control subjects were asked to provide details about themselves, their diabetes (for the diabetic subjects) and their use of prescribed medication, over-the-counter supplements and alternative medications. Subjects were asked to rank their assessment of the effectiveness of each medication. Costs were calculated on a per month basis from average prices obtained from five alternative health stores and five chemist shops. RESULTS: Of the diabetic subjects, 78% were taking prescribed medication for their diabetes, 44% were taking over-the-counter supplements and 31% were taking alternative medications. Of the control subjects, 63% were taking prescribed medication, 51% were taking over-the-counter supplements, and 37% were taking alternative medications. Multivitamins, vitamin E, vitamin C, calcium and aspirin were the most commonly used over the counter supplements. Garlic, echinacea, herbal mixtures, glucosamine were the most commonly used alternative medications. Chromium was used only by diabetic subjects and then only rarely. Subjects rated the effectiveness of the alternative medications significantly lower than for prescribed medications but still thought them efficacious. Alternative medications purported to have some hypoglycaemic effect were little used by diabetic subjects. Diabetic subjects spent almost as much money on over-the-counter supplements and alternative medications together as they did on their diabetic medications. CONCLUSIONS: One-third of diabetic patients are taking alternative medications that they consider efficacious but this is no more than in the control group. The money spent on alternative and non-prescription supplements nearly equals that spent on prescription medications. In view of the money spent in this area the time is past due to evaluate these remedies and to establish what merit they have.


Asunto(s)
Terapias Complementarias , Diabetes Mellitus/terapia , Alberta , Estudios de Casos y Controles , Cromo , Costos y Análisis de Costo , Diabetes Mellitus/economía , Prescripciones de Medicamentos , Femenino , Ajo , Glucosamina/uso terapéutico , Encuestas de Atención de la Salud , Humanos , Entrevistas como Asunto , Magnoliopsida , Masculino , Persona de Mediana Edad , Medicamentos sin Prescripción , Fitoterapia , Plantas Medicinales , Valores de Referencia , Teléfono , Vitaminas
8.
Int J Cancer ; 92(1): 123-9, 2001 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-11279615

RESUMEN

Acquired resistance to antineoplastic agents is a frequent obstacle in tumor therapy. Malignant melanoma cells are particularly well known for their unresponsiveness to chemotherapy; only about 30% of tumors exhibit a transient clinical response to treatment. In our study, we investigated the molecular mechanism of acquired resistance of melanoma cells (MeWo) to the chloroethylating drug fotemustine. Determination of O(6)-methylguanine-DNA methyltransferase (MGMT) activity showed that MeWo cells that acquired resistance to fotemustine upon repeated treatment with the drug display high MGMT activity, whereas the parental cell line had no detectable MGMT. The resistant cell lines exhibit cross-resistance to other O(6)-alkylating agents, such as N-methyl-N'-nitro-N-nitrosoguanidine. Acquired resistance to fotemustine was alleviated by treatment with the MGMT inhibitor O(6)-benzylguanine demonstrating that reactivation of MGMT is the main underlying cause of acquired alkylating drug resistance. As compared with control cells, both MGMT mRNA and MGMT protein were expressed at a high level in fotemustine resistant cells. Southern blot analysis proved that the MGMT gene was not amplified. There was also only an insignificant difference in the CpG methylation pattern of the MGMT promoter whereas a clear hypermethylation in the body of the gene was observed in fotemustine resistant cells. The conclusion that hypermethylation is responsible for reactivation of the MGMT gene gained support by the finding that MGMT activity significantly declined and cells reverted (partially) to the parental sensitive phenotype upon treatment with 5-azacytidine. This is the first report of acquired resistance to a chloroethylating antineoplastic drug of melanoma cells due to gene hypermethylation.


Asunto(s)
Antineoplásicos/uso terapéutico , Reparación del ADN/genética , Resistencia a Antineoplásicos , Guanina/análogos & derivados , Melanoma/tratamiento farmacológico , Melanoma/genética , Compuestos de Nitrosourea/uso terapéutico , O(6)-Metilguanina-ADN Metiltransferasa/genética , Compuestos Organofosforados/uso terapéutico , Azacitidina/farmacología , Southern Blotting , Metilación de ADN/efectos de los fármacos , Activación Enzimática , Inhibidores Enzimáticos/farmacología , Reactivadores Enzimáticos , Amplificación de Genes , Expresión Génica , Guanina/farmacología , Humanos , O(6)-Metilguanina-ADN Metiltransferasa/antagonistas & inhibidores , O(6)-Metilguanina-ADN Metiltransferasa/metabolismo , Regiones Promotoras Genéticas , Células Tumorales Cultivadas
9.
J Rheumatol ; 27(4): 949-52, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10782821

RESUMEN

OBJECTIVE: It is not well appreciated that the clinical presentation of amyloid myopathy can mimic that of polymyositis. By retrospective clinicopathologic analysis we determined distinctive features of amyloid myopathy that differentiate the 2 diseases. METHODS: Two patients with clinical and histologic evidence of an inflammatory myopathy had fatal outcomes despite appropriate treatment for polymyositis. Their clinical course and original pathologic specimens were reviewed. In addition, original tissue samples were obtained and analyzed using Congo red staining and immunoperoxidase. RESULTS: The initial diagnosis of polymyositis was supported in both cases by muscle biopsies showing inflammatory infiltrates and elevations of creatine phosphokinase and by classic electromyography. Retrospective evaluation of the initial muscle biopsies disclosed subtle but incontrovertible evidence of vascular amyloid. Further analysis of the original specimens confirmed the presence of immunoglobin light chain (AL) amyloid. CONCLUSION: Amyloid myopathy can mimic polymyositis. Both can have similar clinical symptoms, as well as inflammatory infiltrates on muscle biopsy. Failure to recognize amyloid myopathy deprives patients of potentially life prolonging treatment. Congo red staining and immunohistochemical analysis of tissue could prevent misdiagnosis.


Asunto(s)
Amiloidosis/patología , Polimiositis/patología , Anciano , Biopsia , Diagnóstico Diferencial , Femenino , Humanos , Persona de Mediana Edad , Mieloma Múltiple/patología , Músculo Esquelético/patología , Miofibrillas/patología
11.
Astrophys J ; 528(1): L49-L51, 2000 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-10587493

RESUMEN

We present observational imaging evidence for the existence of metric radio bursts closely associated with the front edge of coronal mass ejections (CMEs). These radio bursts drift in frequency similarly to type II bursts. They are weak and usually go undetected on spectrograph data. We find the same measured projected velocity for the displacement of, respectively, the radio source (when observed at two or more frequencies) and the CME leading edge. The position of the emitting source coincides with the CME leading edge. Among the events analyzed, the fastest of them, with a velocity over 1400 km s-1, was associated with interplanetary type II bursts.

12.
Dtsch Tierarztl Wochenschr ; 106(4): 179-82, 1999 Apr.
Artículo en Alemán | MEDLINE | ID: mdl-10354652

RESUMEN

After a brief introduction to the most important aspects of the current sport of horse-racing the equipment and tack will be described with respect to the horses wellbeing: bridles, tonguestrap, blinkers, saddle and girth. With reference to incorrect equipment for the rider, the wip and its misuse will be discussed. Problems with saddling and at the starting gate are often indicators of the incorrect application of aids. Then the misuse of the automatic horse trainer, treadmills and swimmingpools will be explained. Finally, the three most important requirements for improving the protection of racehorse are summarized: the racing regulations should conform to animal welfare laws and the application of these laws should be in the hands of an independent veterinary surgeon, who has the authority to enforce its requirement.


Asunto(s)
Caballos , Condicionamiento Físico Animal/instrumentación , Condicionamiento Físico Animal/métodos , Carrera , Bienestar del Animal/normas , Animales , Deportes
13.
Am J Obstet Gynecol ; 180(5): 1240-3, 1999 May.
Artículo en Inglés | MEDLINE | ID: mdl-10329884

RESUMEN

OBJECTIVE: Our purpose was to increase the number of the progenitor cells in umbilical cord blood collected for transplantation. STUDY DESIGN: We randomly assessed the effect of "upper" and "lower" positions of the newborn on the volume and progenitor cell (CD34(+)) content of the umbilical cord blood collected from 49 healthy, vaginally delivered, term neonates. RESULTS: Twenty-two collections were performed in the "upper" and 27 in the "lower" position. The volume of umbilical cord blood obtained in the "upper" position was 108.1 +/- 19.1 mL compared with 42.6 +/- 19.5 mL in the "lower" position (P <.0001). Mononuclear cell separation revealed significantly higher numbers of cells in umbilical cord blood obtained in the "upper" group (P <.01). Although the percentage of CD34(+) cells was comparable, the absolute number of CD34(+) cells was significantly higher in the "upper" group because of the larger volume collected (P <.02). At 24 hours after delivery the hemoglobin levels were not significantly different between newborns of the 2 groups. CONCLUSIONS: Placing the newborn on the maternal abdomen after delivery and before cord clamping may significantly increase the volume of umbilical cord blood collected and therefore the CD34(+) counts that improve transplantation success without placing the mother or the newborn at risk.


Asunto(s)
Antígenos CD34/análisis , Parto Obstétrico , Sangre Fetal/citología , Células Madre Hematopoyéticas/citología , Recién Nacido/fisiología , Postura , Volumen Sanguíneo , Recuento de Células , Separación Celular , Femenino , Células Madre Hematopoyéticas/inmunología , Humanos , Masculino , Embarazo , Cordón Umbilical
14.
Int J Cancer ; 80(5): 744-50, 1999 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-10048977

RESUMEN

Malignant melanoma is well known for its primary unresponsiveness to chemotherapy. The mechanisms conferring this intrinsic resistance are unclear. In this study, we investigated the role of genes involved in DNA repair in a panel of human melanoma cell variants exhibiting low and high levels of resistance to 4 commonly used drugs in melanoma treatment, i.e., vindesine, etoposide, fotemustine and cisplatin. We show that in melanoma cells exhibiting resistance to cisplatin, etoposide and vindesine, the nuclear content of each of the DNA mismatch repair (MMR) proteins hMLH1, hMSH2 and hMSH6 was reduced by 30-70%. A decreased expression level of up to 80% of mRNAs encoding hMLH1 and hMSH2 was observed in drug-resistant melanoma cells selected for cisplatin, etoposide and fotemustine, while vindesine-selected cells showed only moderate reduction. In melanoma cells that acquired resistance to fotemustine, the amount of nuclear MMR proteins was nearly unaltered, whereas the activity of O6-methylguanine-DNA methyltransferase (MGMT) was considerably enhanced. Activity of N-methylpurine-DNA glycosylase (MPG) was not significantly altered in any of the drug-resistant melanoma cells. Our data indicate that modulation of both MMR components and MGMT expression level may contribute to the drug-resistant phenotype of melanoma cells.


Asunto(s)
Antineoplásicos/toxicidad , ADN Glicosilasas , Reparación del ADN , Proteínas de Unión al ADN/genética , Resistencia a Múltiples Medicamentos , N-Glicosil Hidrolasas/genética , Proteínas de Neoplasias/genética , O(6)-Metilguanina-ADN Metiltransferasa/genética , Proteínas Proto-Oncogénicas/genética , Transcripción Genética , Proteínas Adaptadoras Transductoras de Señales , Proteínas Portadoras , Cisplatino/toxicidad , Etopósido/toxicidad , Humanos , Melanoma , Homólogo 1 de la Proteína MutL , Proteína 2 Homóloga a MutS , Compuestos de Nitrosourea/toxicidad , Proteínas Nucleares , Compuestos Organofosforados/toxicidad , Regiones Promotoras Genéticas , ARN Mensajero/genética , Vindesina/toxicidad
15.
Br J Haematol ; 103(3): 639-50, 1998 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9858211

RESUMEN

Cord blood (CB) transplantation is primarily performed in children, rather than in adults, due to the low number of haemopoietic progenitor cells obtained from the small volume of a single CB collection. Prolonged thrombocytopenia is a major problem following CB transplantation. Efforts are currently underway to expand the number of CB progenitor cells ex vivo, in order to enable transplantation in adults and to decrease the period of thrombocytopenia. In this study we investigated different techniques for enrichment and expansion of megakaryocyte (Mk) progenitor cells and haemopoietic stem cells from CB. CBs from 20 normal deliveries were depleted of red blood cells (RBC) by dividing each sample and testing cell separation on 3% gelatin, Hespan, Ficoll-Paque or a two-step 3% gelatin followed by Ficoll-Paque separation. The two-step procedure was found to be superior to the other methods in enrichment of the Mk progenitor cells (CFU-Mk) (34.3-fold), while at the same time retaining the number of myeloid and erythroid progenitors, CD34+ and CD41+ cells. In short-term (14d) liquid culture of non-adherent nucleated cells isolated by gelatin and Ficoll-Paque, a 40-fold expansion of clonable Mk progenitor cells was obtained in the presence of thrombopoietin (r-hu-TPO) and stem cell factor (r-hu-sCF. In similar cultures of isolated CD34+ cells, a 100-fold clonable Mk progenitor was obtained at day 14. Therefore this new technique may facilitate the ex vivo expansion of Mk progenitor cells and be adopted for future use in CB transplantation.


Asunto(s)
Separación Celular/métodos , Sangre Fetal/citología , Trasplante de Células Madre Hematopoyéticas/métodos , Células Madre Hematopoyéticas/fisiología , Megacariocitos/fisiología , Adulto , Antígenos CD34 , Ensayo de Unidades Formadoras de Colonias , Células Precursoras Eritroides/fisiología , Movilización de Célula Madre Hematopoyética/métodos , Humanos , Separación Inmunomagnética/métodos , Fenotipo , Trombopoyetina/uso terapéutico
17.
Br J Haematol ; 98(1): 51-6, 1997 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9233563

RESUMEN

Several clinical and laboratory findings suggest the presence of a chronic hypercoagulable state in patients with beta-thalassaemia major (TM). We have previously shown that isolated TM red blood cells (RBC) strongly enhance prothrombin activation, suggesting an increased membrane exposure of procoagulant phospholipids (i.e. phosphatidylserine). In this study we quantitated the procoagulant activity of RBC in TM and thalassaemia intermedia (TI) patients. We also determined the fraction of activated platelets expressing p-selectin (CD62p) or CD63 in these subjects. Both assays were performed by dual-colour flow cytometry. A significantly (P < 0.01) higher fraction of FITC-annexin V-labelled RBC was found in TM and TI patients, compared to the controls. A highly significant correlation (P < 0.001) was found in TM patients between the number of RBC-bound annexin V molecules and the fraction of CD62p (p-selectin) or CD63-positive platelets. This association between annexin V binding to TM RBC and the expression of platelet activation markers was also found in individual TM patients over time. Thus, the procoagulant surface of TM RBC may accelerate thrombin generation in vivo which, in turn, triggers platelet activation.


Asunto(s)
Anexina A5/metabolismo , Antígenos CD/metabolismo , Selectina-P/metabolismo , Activación Plaquetaria/fisiología , Glicoproteínas de Membrana Plaquetaria/metabolismo , Talasemia beta/sangre , Adolescente , Adulto , Trastornos de la Coagulación Sanguínea/sangre , Trastornos de la Coagulación Sanguínea/etiología , Niño , Eritrocitos/metabolismo , Femenino , Humanos , Masculino , Tetraspanina 30
18.
J Am Diet Assoc ; 96(12): 1254-61, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8948386

RESUMEN

OBJECTIVE: To evaluate the long-term effects oat bran concentrate bread products in the diet of free-living subjects with non-insulin-dependent diabetes (NIDDM) via dietary, clinical, and biochemical methods. DESIGN: A 24-week crossover study consisting of two 12-week periods. SUBJECTS/SETTING: Eight men with NIDDM (mean age = 45 years) who lived in the community. Glucose and insulin profiles were conducted in a clinical investigation unit. INTERVENTION: Palatable, high-fiber, oat bran concentrate (soluble fiber [beta-glucan] content = 22.8%) bread products were developed. Four randomly chosen subjects ate oat bran concentrate breads first; the other subjects ate control white bread first. MAIN OUTCOME MEASURES: Dietary intake (four 48-hour dietary recalls per period) was assessed. Blood glucose and insulin (8-hour profiles) and lipid parameters after fasting were measured (at 0, 12, and 24 weeks). STATISTICAL ANALYSES PERFORMED: Analysis of variance and repeated-measures analysis of variance. RESULTS: Total energy and macronutrient intakes were similar in both periods. Mean total dietary fiber intake was 19 g/day in the white bread period and 34 g/day (9 g soluble fiber per day from oat bran concentrate) in the oat bran concentrate period. Body weight remained stable. Mean glycemic and insulin response areas (area under the curve) were lower (P < or = .05 and not significant, respectively) for the oat bran concentrate period than the white bread period. After breakfast, area under the curve for the oat bran concentrate period was lower for glucose (P < or = .01) and insulin (P < or = .05); insulin peak was reached earlier (P < or = .05) than in the white bread period. Dietary fiber intake was correlated negatively with insulin area under the curve (P < or = .05). Mean total plasma cholesterol and low-density lipoprotein cholesterol levels were lower (P < or = .01) in the oat bran concentrate period than in the white bread period. In the oat bran concentrate period, the mean ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol was reduced by 24% (P < or = .05). CONCLUSIONS: The well-accepted oat bran concentrate bread products improved glycemic, insulinemic, and lipidemic responses.


Asunto(s)
Avena , Pan , Diabetes Mellitus Tipo 2/dietoterapia , Fibras de la Dieta/uso terapéutico , Adulto , Área Bajo la Curva , Glucemia/análisis , Colesterol/sangre , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Estudios Cruzados , Fibras de la Dieta/administración & dosificación , Ingestión de Alimentos , Humanos , Insulina/sangre , Masculino , Persona de Mediana Edad , Proyectos Piloto
19.
Haemostasis ; 26 Suppl 4: 37-45, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8979110

RESUMEN

Endothelial injury caused by viruses usually involves viral replication or transformation. We report a novel mechanism of endothelial damage by a toxic viral protein. We have isolated a new retrovirus from hemangiosarcomas which appeared among layer hens. The isolated avian hemangiosarcoma virus (AHV) is capable of inducing hemangiomas in hens in-vivo and causes a cytopathic effect (CPE) and loss of thromboresistance in cultured bovine aortic endothelial cells (BAEC). These effects do not require viral replication and can be induced by purified AHV envelop glycoprotein (gp85). AHV causes CPE in BAEC through a typical programmed cell death (apoptosis). Quiescent G0/G1-BAEC are much more sensitive to AHV induced apoptosis than actively dividing cells. These experiments demonstrate the capacity of viral proteins to affect the integrity and functionality of vascular endothelial cells.


Asunto(s)
Apoptosis , Virus del Sarcoma Aviar/patogenicidad , Pollos/virología , Endotelio Vascular/lesiones , Hemangiosarcoma/veterinaria , Enfermedades de las Aves de Corral/virología , Sarcoma Aviar/virología , Trombosis/etiología , Proteínas del Envoltorio Viral/farmacología , Animales , Aorta/citología , Virus del Sarcoma Aviar/aislamiento & purificación , Bovinos , Ciclo Celular , Células Cultivadas , Efecto Citopatogénico Viral , Endotelio Vascular/patología , Endotelio Vascular/virología , Matriz Extracelular/metabolismo , Hemangiosarcoma/complicaciones , Hemangiosarcoma/virología , Inmunidad Innata , Sarcoma Aviar/complicaciones , Tromboxano A2/biosíntesis
20.
Virology ; 223(1): 233-7, 1996 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-8806557

RESUMEN

Hemangiomas are localized tumors of vascular cells which appear frequently in humans and animals, and their mode of induction is unknown. Recently, a new field strain of avian retrovirus, avian hemangioma virus (AHV), was isolated from spontaneous hemangiomas in layer hens. Sequence analysis of the AHV genome revealed the presence of three prototypic retroviral genes, gag, pol, and env, but no oncogenes. AHV was capable of inducing hemangiomas in hens in vivo, but it induced a strong cytopathic effect in cultured endothelial cells. The AHV envelope glycoprotein, gp85, was found to be responsible for the cell-killing effect. Four independent lines of experimental evidence indicated that AHV induces a cytopathic effect through a typical programmed cell death, apoptosis: (i) morphological changes in cells visualized by light microscopy, (ii) nuclear condensation and fragmentation indicated by 4',6-diamidino-2- phenylindole staining, (iii) intranucleosomal degradation of DNA demonstrated by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling staining, and (iv) flow cytometry analysis of the DNA content of the infected cells. Quiescent endothelial G0/G1 cells were much more sensitive to AHV-induced apoptosis than actively dividing cells, suggesting that the AHV ability to induce apoptosis is dependent on the proliferative state of the infected cells.


Asunto(s)
Apoptosis , Endotelio Vascular/virología , Hemangioma/virología , Retroviridae/patogenicidad , Animales , Bovinos , Células Cultivadas , Efecto Citopatogénico Viral , Fragmentación del ADN , Endotelio Vascular/patología , Proteínas del Envoltorio Viral/metabolismo
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