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1.
BMC Med Educ ; 22(1): 152, 2022 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-35255874

RESUMEN

BACKGROUND: Bedside teaching (BST) facilitates medical education and has reduced in practice, often due to patient-related concerns. This study aimed to validate a questionnaire exploring patients attitudes towards BST. METHODS: International guidelines for questionnaire development were followed. Seven steps were included: literature review, patient interviews, development of clear and understandable items, expert validation, cognitive interviewing and pilot testing. Statistical analyses included exploratory factor analysis, internal consistency, investigation of demographic influences and discriminant validity across subscales. RESULTS: Following the literature review, 32 interviews were conducted. Potential items were developed, reviewed and adapted. Experts in medical education and statistics reviewed the draft questionnaire. Fifteen patients consented to cognitive testing and 401 consenting patients completed the final version. The median age of participants was 35 years of age (range: 18 to 70 years). Participants included women attending for antenatal (40%), postnatal (32%) and gynaecology issues (28%). Just under one third (29%) had taken part in medical student teaching previously. Statistical analyses found a two-factor solution, consisting of Educate medical professionals and Conditions for participation subscales with good internal consistency; responses did not vary by age or education. Participants who had opted-in for teaching in the ward and bedside endorsed higher levels of Educate medical professionals, suggesting discriminant validity. A majority of patients (> 92%) reported that they were happy to be involved in BST. Patients believed that they should not be asked to participate in BST should they feel stressed or unwell (68.2%). CONCLUSION: This study shows extensive patient support for BST, independent of age or education. The desire to educate is a strong motivating factor. This strong support by patients for BST is an area that medical schools and universities can potentially develop. Future versions of this questionnaire may include virtual bedside teaching, in the context of social distancing.


Asunto(s)
Educación Médica , Estudiantes de Medicina , Adolescente , Adulto , Anciano , Actitud , Análisis Factorial , Femenino , Humanos , Persona de Mediana Edad , Embarazo , Psicometría , Reproducibilidad de los Resultados , Encuestas y Cuestionarios , Enseñanza , Adulto Joven
2.
Sci Robot ; 2(6)2017 05 31.
Artículo en Inglés | MEDLINE | ID: mdl-33157872

RESUMEN

Prosthetic limb control is fundamentally constrained by the current amputation procedure. Since the U.S. Civil War, the external prosthesis has benefited from a pronounced level of innovation, but amputation technique has not significantly changed. During a standard amputation, nerves are transected without the reintroduction of proper neural targets, causing painful neuromas and rendering efferent recordings infeasible. Furthermore, the physiological agonist-antagonist muscle relationships are severed, precluding the generation of musculotendinous proprioception, an afferent feedback modality critical for joint stability, trajectory planning, and fine motor control. We establish an agonist-antagonist myoneural interface (AMI), a unique surgical paradigm for amputation. Regenerated free muscle grafts innervated with transected nerves are linked in agonist-antagonist relationships, emulating the dynamic interactions found within an intact limb. Using biomechanical, electrophysiological, and histological evaluations, we demonstrate a viable architecture for bidirectional signaling with transected motor nerves. Upon neural activation, the agonist muscle contracts, generating electromyographic signal. This contraction in the agonist creates a stretch in the mechanically linked antagonist muscle, producing afferent feedback, which is transmitted through its motor nerve. Histological results demonstrate regeneration and the presence of the spindle fibers responsible for afferent signal generation. These results suggest that the AMI will not only produce robust signals for the efferent control of an external prosthesis but also provide an amputee's central nervous system with critical musculotendinous proprioception, offering the potential for an enhanced prosthetic controllability and sensation.

3.
Mol Cell Biochem ; 427(1-2): 103-109, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27995412

RESUMEN

We have previously demonstrated that the E3 ligase Human Constitutive Photomorphogenic Protein (huCOP1) is expressed in human keratinocytes and negatively regulates p53. The MutS homolog 2 (MSH2) protein plays a central role in DNA MMR mechanism and is implicated in the cellular response to anticancer agents, such as cisplatin. Our aim was to clarify whether huCOP1 plays a role in DNA MMR by affecting MSH2 protein level in human keratinocytes. To define the role of huCOP1 in DNA mismatch repair, we determined whether huCOP1 affects MSH2 abundance. MSH2 protein level was detected by immunocytochemical staining using a keratinocyte cell line in which the expression level of huCOP1 was stably decreased (siCOP1). To investigate whether huCOP1 silencing influences cisplatin-induced cell death, control and siCOP1 keratinocyte cells were treated with increasing concentrations of cisplatin and cell viability was recorded after 48 and 96 h. Stable silencing of huCOP1 in human keratinocytes resulted in a reduced level of MSH2 protein. huCOP1 silencing also sensitized keratinocytes to the interstrand crosslinking inducer cisplatin. Our results indicate that decreased huCOP1 correlates with lower MSH2 levels. These protein level changes lead to increased sensitivity toward cisplatin treatment, implicating that huCOP1 plays a positive role in maintaining genome integrity in human keratinocytes.


Asunto(s)
Reparación del ADN , Inestabilidad Genómica/fisiología , Queratinocitos/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Línea Celular Transformada , Cisplatino/farmacología , Inestabilidad Genómica/efectos de los fármacos , Humanos , Proteína 2 Homóloga a MutS/metabolismo , Proteína p53 Supresora de Tumor/metabolismo
4.
Br J Surg ; 103(13): 1804-1814, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27642053

RESUMEN

BACKGROUND: The application of safety principles from the aviation industry to the operating room has offered hope in reducing surgical complications. This study aimed to assess the impact on major surgical complications of adding an aviation-based team training programme after checklist implementation. METHODS: A prospective parallel-group cluster trial was undertaken between September 2011 and March 2013. Operating room teams from 31 hospitals were assigned randomly to participate in a team training programme focused on major concepts of crew resource management and checklist utilization. The primary outcome measure was the occurrence of any major adverse event, including death, during the hospital stay within the first 30 days after surgery. Using a difference-in-difference approach, the ratio of the odds ratios (ROR) was estimated to compare changes in surgical outcomes between intervention and control hospitals. RESULTS: Some 22 779 patients were enrolled, including 5934 before and 16 845 after team training implementation. The risk of major adverse events fell from 8·8 to 5·5 per cent in 16 intervention hospitals (adjusted odds ratio 0·57, 95 per cent c.i. 0·48 to 0·68; P < 0·001) and from 7·9 to 5·4 per cent in 15 control hospitals (odds ratio 0·64, 0·50 to 0·81; P < 0·001), resulting in the absence of difference between arms (ROR 0·90, 95 per cent c.i. 0·67 to 1·21; P = 0·474). Outcome trends revealed significant improvements among ten institutions, equally distributed across intervention and control hospitals. CONCLUSION: Surgical outcomes improved substantially, with no difference between trial arms. Successful implementation of an aviation-based team training programme appears to require modification and adaptation of its principles in the context of the the surgical milieu. Registration number: NCT01384474 (http://www.clinicaltrials.gov).


Asunto(s)
Complicaciones Intraoperatorias/prevención & control , Grupo de Atención al Paciente , Complicaciones Posoperatorias/prevención & control , Especialidades Quirúrgicas/educación , Lista de Verificación , Análisis por Conglomerados , Femenino , Hospitales Privados , Hospitales Públicos , Humanos , Capacitación en Servicio , Complicaciones Intraoperatorias/etiología , Masculino , Persona de Mediana Edad , Quirófanos , Complicaciones Posoperatorias/etiología , Estudios Prospectivos
5.
Am J Transplant ; 15(5): 1421-31, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25777324

RESUMEN

Current immunosuppression in VCA is largely based on the experience in solid organ transplantation. It remains unclear if steroids can be reduced safely in VCA recipients. We report on five VCA recipients who were weaned off maintenance steroids after a median of 2 months (mean: 4.8 months, range 2-12 months). Patients were kept subsequently on a low dose, dual maintenance consisting of tacrolimus and mycophenolate mofetil/mycophenloic acid with a mean follow-up of 43.6 months (median = 40 months, range 34-64 months). Early and late acute rejections responded well to temporarily augmented maintenance, topical immunosuppression, and/or steroid bolus treatment. One late steroid-resistant acute rejection required treatment with thymoglobulin. All patients have been gradually weaned off steroids subsequent to the treatment of acute rejections. Low levels of tacrolimus (<5 ng/mL) appeared as a risk for acute rejections. Although further experience and a cautious approach are warranted, dual-steroid free maintenance immunosuppression appears feasible in a series of five VCA recipients.


Asunto(s)
Trasplante Facial , Trasplante de Mano , Terapia de Inmunosupresión/métodos , Inmunosupresores/uso terapéutico , Esteroides/uso terapéutico , Alotrasplante Compuesto Vascularizado , Adulto , Anciano , Suero Antilinfocítico/uso terapéutico , Femenino , Rechazo de Injerto , Humanos , Masculino , Persona de Mediana Edad , Ácido Micofenólico/administración & dosificación , Ácido Micofenólico/análogos & derivados , Tacrolimus/administración & dosificación , Factores de Tiempo , Injerto Vascular
6.
Br J Surg ; 101(12): 1491-8; discussion 1498, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25228439

RESUMEN

BACKGROUND: Calls for greater transparency with improved quality, safety and outcomes have led to performance tracking of individual surgeons. This study evaluated the methodology of studies investigating individual performance in surgery. METHODS: MEDLINE, Embase, PsycINFO, AMED and the Cochrane Database of Systematic Reviews (from their inception to July 2014) were searched. Two authors independently reviewed citations using predetermined inclusion and exclusion criteria; 91 data points per study were extracted. RESULTS: The search strategy yielded 8514 citations; 101 were eligible, comprising 1 006 037 procedures by 14 455 surgeons. Thirty-four studies were prospective and 66 were retrospective. The aim of the studies was either to assess individual performance and describe the learning curve of a procedure, to describe factors influencing performance, or to describe methods for routine performance monitoring. Some 51·5 per cent of the studies investigated 500 or fewer procedures. Most (77 of 101) were single-centre studies. Less than half of the studies (42, 41·6 per cent) employed statistical modelling or stratification to adjust performance measures. Forty studies (39·6 per cent) adjusted outcomes for case mix. Seventeen (16·8 per cent) adjusted metrics for surgeon-specific factors. Thirteen studies (12·9 per cent) considered clustering in their analyses. The most frequent outcome studied was duration of operation (59·4 per cent), followed by complication rate (45·5 per cent) and reoperation rate (29·7 per cent); 15·8 per cent of studies recorded mortality, and 4·0 per cent explored patient satisfaction. Only 48·5 per cent of studies displayed procedural learning curves using a graph. CONCLUSION: There exist substantial shortcomings in methodological quality, outcome measurements and quality improvement evaluation among current studies of individual surgical performance. Methodological guidelines should be established to ensure that assessments are valid.


Asunto(s)
Competencia Clínica/normas , Cirujanos/normas , Métodos Epidemiológicos , Humanos , Curva de Aprendizaje , Tempo Operativo , Evaluación del Resultado de la Atención al Paciente , Cirujanos/educación
7.
Brain Res ; 1402: 9-19, 2011 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-21696706

RESUMEN

Damage to major white matter tracts is a hallmark mark feature of hypoxic-ischemic (HI) brain injury in the preterm neonate. There is, however, no therapeutic intervention to treat this injury. Neuroinflammation is thought to play a prominent role in the pathogenesis of the HI-induced white matter damage but identification of the key mediators that constitute the inflammatory response remain to be fully elucidated. Cyclooxygenase enzymes (COX-1 and COX-2) are candidate neuroinflammatory mediators that may contribute to the HI-induced demise of early oligodendrocyte progenitors and myelination. We investigated whether ibuprofen, a non-steroidal anti-inflammatory drug that inhibits COX enzymes, can attenuate neuroinflammation and associated white matter damage incurred in a rodent model of preterm HI. On postnatal day 3 (P3), HI was produced (right carotid artery ligation and 30 min 6% O(2)). An initial dose of ibuprofen (100mg/kg, s.c.) was administered 2h after HI followed by a maintenance dose (50mg/kg, s.c.) every 24h for 6 days. Post-HI ibuprofen treatment significantly attenuated the P3 HI-induced increases in COX-2 protein expression as well as interleukin-1beta (IL-1ß) and tumour necrosis factor-alpha (TNF-α) levels in the brain. Ibuprofen treatment also prevented the HI-induced loss O4- and O1-positive oligodendrocyte progenitor cells and myelin basic protein (MBP)-positive myelin content one week after P3 HI. These findings suggest that a repeated, daily, ibuprofen treatment regimen administered after an HI insult may be a potential therapeutic intervention to prevent HI-induced damage to white matter progenitors and early myelination in the preterm neonate.


Asunto(s)
Encefalitis/prevención & control , Hipoxia-Isquemia Encefálica/tratamiento farmacológico , Ibuprofeno/farmacología , Fibras Nerviosas Mielínicas/efectos de los fármacos , Animales , Animales Recién Nacidos , Modelos Animales de Enfermedad , Encefalitis/patología , Encefalitis/fisiopatología , Humanos , Hipoxia-Isquemia Encefálica/patología , Hipoxia-Isquemia Encefálica/fisiopatología , Recién Nacido , Leucomalacia Periventricular/tratamiento farmacológico , Leucomalacia Periventricular/patología , Leucomalacia Periventricular/fisiopatología , Fibras Nerviosas Mielínicas/patología , Ratas , Ratas Sprague-Dawley
8.
Clin Exp Immunol ; 161(3): 397-406, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20560984

RESUMEN

Toll-like receptors (TLRs) have a central role in innate immunity as they detect conserved pathogen-associated molecular patterns (PAMPs) on a range of microbes, including viruses, leading to innate immune activation and orchestration of the adaptive immune response. To date, a large number of viruses have been shown to trigger innate immunity via TLRs, suggesting that these receptors are likely to be important in the outcome to viral infection. This suggestion is supported by the observation that many viruses have evolved mechanisms not only to evade the innate immune system, but also to subvert it for the benefit of the virus. In this review we will discuss earlier evidence, mainly from knock-out mice studies, implicating TLRs in the innate immune response to viruses, in light of more recent clinical data demonstrating that TLRs are important for anti-viral immunity in humans.


Asunto(s)
Inmunidad Innata/inmunología , Transducción de Señal/inmunología , Receptores Toll-Like/inmunología , Virosis/inmunología , Animales , Citocinas/inmunología , Citocinas/metabolismo , Humanos , Modelos Inmunológicos , Receptor Toll-Like 1/inmunología , Receptor Toll-Like 1/metabolismo , Receptor Toll-Like 2/inmunología , Receptor Toll-Like 2/metabolismo , Receptores Toll-Like/metabolismo , Virosis/metabolismo
9.
Biochem Soc Trans ; 31(Pt 1): 252-6, 2003 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-12546696

RESUMEN

The human skin cancer-prone disease xeroderma pigmentosum variant (XPV) results from a mutation in RAD30, which encodes the novel lesion bypass DNA polymerase eta. XPV cells are characterized by delayed completion of DNA replication and increased mutagenesis following UV irradiation. In cell-free extracts of XPV lymphoblasts, functional DNA polymerase eta is required for the complete replication of a double-stranded plasmid containing either a single (6-4) photoproduct or a cyclobutane pyrimidine dime(CPD), the major mutagenic UV-induced lesion. In cultured XPV cells, replication arrest activates downstream signalling pathways, leading to hyperphosphorylation of the 34-kDa subunit of the trimeric single-stranded DNA-binding protein, RPA (replication protein A). Many of the RAD30 mutations identified in XPV cells result in truncation and inactivation of DNA polymerase eta. To examine whether polymorphisms in the RAD30 gene that result in altered polymerase eta function, rather than enzyme inactivation, might contribute to individual susceptibility to skin cancer, methods to screen for sequence changes in the RAD30 gene in human genomic DNAhave been developed.


Asunto(s)
ADN Polimerasa Dirigida por ADN/fisiología , Predisposición Genética a la Enfermedad , Neoplasias/genética , Animales , ADN Polimerasa Dirigida por ADN/química , ADN Polimerasa Dirigida por ADN/genética , Humanos , Mutación , Fosforilación , Neoplasias Cutáneas/genética , Rayos Ultravioleta , Xerodermia Pigmentosa/genética
10.
Biochem Soc Trans ; 31(Pt 1): 257-62, 2003 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-12546697

RESUMEN

BRCA1 (breast-cancer susceptibility gene 1) is a tumour suppressor gene that is mutated in the germline of women with a genetic predisposition to breast and ovarian cancer. In this review, we examine the role played by BRCA1 in mediating the cellular response to stress. We review the role played by BRCA1 in detecting and signalling the presence of DNA damage, particularly double-strand DNA breaks, and look at the evidence to support a role for BRCA1 in regulating stress response pathways such as the c-Jun N-terminal kinase/stress-activated protein kinase pathway. In addition, we examine the role played by BRCA1 in mediating both cell-cycle arrest and apoptosis following different types of cellular insult, and how this may be modulated by the presence or absence of associated proteins such as p53. Finally, we explore the possibility that many of the functions associated with BRCA1 may be based on transcriptional regulation of key downstream genes that have been implicated in the regulation of these specific cellular pathways.


Asunto(s)
Proteína BRCA1/fisiología , Daño del ADN , Reparación del ADN , Genes BRCA1 , Transcripción Genética , Animales , Apoptosis , Northern Blotting , Ciclo Celular , Fase G2 , Humanos , Interferón gamma/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Mitosis , Paclitaxel/farmacología , Estrés Fisiológico , Factores de Tiempo , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/metabolismo , Rayos Ultravioleta
11.
Environ Mol Mutagen ; 38(1): 19-29, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11473384

RESUMEN

The human skin cancer-prone disease xeroderma pigmentosum variant (XPV) results from a mutation in the human RAD30 gene, which encodes the lesion bypass DNA polymerase eta. XPV cells are characterized by delayed completion of DNA replication and increased mutagenesis following UV-irradiation. Using extracts of an XPV lymphoblast cell line (GM2449C) that has a truncating mutation in the RAD30 gene, we investigated the effect of a (6-4) photoproduct and a cyclobutane pyrimidine dimer (CPD), at a unique -TT- site on either the leading or lagging strand, on plasmid DNA replication. Compared to normal cell extracts, XPV cell extracts have a reduced capacity to carry out complete replication of DNA containing either a (6-4) photoproduct or a CPD on the leading strand, whereas there is little difference between the two cell extracts in replication of DNA containing a lesion on the lagging strand. Inhibition of replication in the presence of a (6-4) photoproduct is attributed to arrest of nascent DNA strand synthesis at the lesion site; in XPV cell extracts, the proportion of arrested products is increased compared to that of normal cell extracts. These results are consistent with a requirement for functional DNA polymerase eta in the replication of a double-stranded plasmid containing either a (6-4) photoproduct or a CPD, on the leading but not the lagging strand.


Asunto(s)
Replicación del ADN/efectos de los fármacos , Plásmidos , Dímeros de Pirimidina/farmacología , Xerodermia Pigmentosa/genética , Secuencia de Bases , Extractos Celulares , ADN/efectos de los fármacos , Desoxirribonucleasas de Localización Especificada Tipo II/metabolismo , Electroforesis en Gel de Agar , Técnicas In Vitro
12.
Mutat Res ; 476(1-2): 21-8, 2001 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-11336980

RESUMEN

The ability to detect the most common type of UV-induced mutation, the C to T transition, at the previously characterized hotspot at position 99 of the supF gene has been demonstrated in a selectively irradiated reversion vector, pLS189(Rev). The supF region was amplified, irradiated with 500J/m(2) UVC or unirradiated, and ligated into the pLS189(Rev) plasmid. A portion of ligated product plasmid containing the irradiated fragment was sensitive to nicking by T4 endonuclease V, indicating the presence of the most common type of UV-induced damage, the pyrimidine dimer. Plasmid containing the irradiated or unirradiated supF gene was replicated completely in cellular extracts from either HeLa or XP-A cells in vitro. Plasmid containing the irradiated supF gene showed an inhibition of total replication to a level similar to those of previous studies with plasmid molecules exposed in their entirety to 40J/m(2). Replication of selectively irradiated plasmid resulted in an average reversion frequency of 0.071% in the two extracts; a 42-fold increase over the average spontaneous reversion frequency of unirradiated plasmid. The reversion frequencies were not significantly different between extracts prepared from HeLa and XP-A cells, indicating that neither the repair status of the cell lines nor the XPA protein itself affect the frequency of C to T transitions at position 99 of the supF gene in plasmid replicated in vitro. These data indicate that the plasmid pSL189(Rev), containing the selectively UV-irradiated supF gene, is a useful and sensitive tool to study mutagenesis at a specific site. This approach may be applicable to the investigation of other environmental DNA-damaging agents, by allowing the target gene to be selectively damaged while maintaining the ability of the plasmid to replicate completely. Such a system, amenable to biochemical manipulation, may be very valuable in elucidating the function of novel proteins in the process of mutagenesis.


Asunto(s)
Daño del ADN , Vectores Genéticos , ARN de Transferencia/genética , Secuencia de Bases , Línea Celular Transformada , Cartilla de ADN/genética , Replicación del ADN/efectos de la radiación , Genes Supresores , Células HeLa , Humanos , Técnicas In Vitro , Mutagénesis , Plásmidos/genética , Mutación Puntual , Rayos Ultravioleta/efectos adversos , Xerodermia Pigmentosa/genética
13.
Mol Biol Cell ; 12(5): 1199-213, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11359916

RESUMEN

Exposure to DNA-damaging agents triggers signal transduction pathways that are thought to play a role in maintenance of genomic stability. A key protein in the cellular processes of nucleotide excision repair, DNA recombination, and DNA double-strand break repair is the single-stranded DNA binding protein, RPA. We showed previously that the p34 subunit of RPA becomes hyperphosphorylated as a delayed response (4-8 h) to UV radiation (10-30 J/m(2)). Here we show that UV-induced RPA-p34 hyperphosphorylation depends on expression of ATM, the product of the gene mutated in the human genetic disorder ataxia telangiectasia (A-T). UV-induced RPA-p34 hyperphosphorylation was not observed in A-T cells, but this response was restored by ATM expression. Furthermore, purified ATM kinase phosphorylates the p34 subunit of RPA complex in vitro at many of the same sites that are phosphorylated in vivo after UV radiation. Induction of this DNA damage response was also dependent on DNA replication; inhibition of DNA replication by aphidicolin prevented induction of RPA-p34 hyperphosphorylation by UV radiation. We postulate that this pathway is triggered by the accumulation of aberrant DNA replication intermediates, resulting from DNA replication fork blockage by UV photoproducts. Further, we suggest that RPA-p34 is hyperphosphorylated as a participant in the recombinational postreplication repair of these replication products. Successful resolution of these replication intermediates reduces the accumulation of chromosomal aberrations that would otherwise occur as a consequence of UV radiation.


Asunto(s)
Reparación del ADN/genética , Replicación del ADN/fisiología , Proteínas de Unión al ADN/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Rayos Ultravioleta , Secuencia de Aminoácidos , Afidicolina/farmacología , Proteínas de la Ataxia Telangiectasia Mutada , Proteínas de Ciclo Celular , Fraccionamiento Celular , Línea Celular , Medio de Cultivo Libre de Suero , Daño del ADN , Replicación del ADN/genética , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/efectos de la radiación , Inhibidores Enzimáticos/farmacología , Humanos , Immunoblotting , Datos de Secuencia Molecular , Mapeo Peptídico , Fosforilación , Proteínas Serina-Treonina Quinasas/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteína de Replicación A , Proteínas Supresoras de Tumor , Xerodermia Pigmentosa/genética
14.
Environ Mol Mutagen ; 37(2): 128-40, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11246219

RESUMEN

Ataxia telangiectasia (A-T) is a human genetic disorder characterized by progressive cerebellar degeneration, hypersensitivity to ionizing radiation (IR), immunodeficiency, and high cancer risk. At the cellular level, IR sensitivity and increased frequency of spontaneous and IR-induced chromosomal breakage and rearrangements are the hallmarks of A-T. The ATM gene, mutated in this syndrome, has been cloned and codes for a protein sharing homology with DNA-PKcs, a protein kinase involved in DNA double-strand break (DSB) repair and DNA damage responses. The characteristics of the A-T cellular phenotypes and ATM gene suggest that ATM may play a role similar to that of DNA-PKcs in DSB repair and that there is a primary DNA repair defect in A-T cells. In the current study, the function of ATM in DNA DSB repair was evaluated in an in vitro system using two plasmids, carrying either an EcoRI-induced DSB within the lacZalpha gene or various endonuclease-induced DSB in the SupF suppressor tRNA gene. We found that the DSB repair efficiency in A-T nuclear extracts was comparable to, if not higher than, that in normal nuclear extracts. However, the repair fidelity in A-T nuclear extracts was decreased when repairing DSB with short 5' and 3' overhangs (<4 base pairs (bp)) or blunt ends, but not 5' 4-bp overhangs. Sequencing of the mutant plasmids revealed that deletions involving 1-6 nucleotide microhomologies were the major class of mutations in both A-T and normal extracts. However, the size of the deletions in plasmids from A-T nuclear extracts was larger than that from normal nuclear extracts. Expression of the ATM protein in A-T cells corrected the defect in DSB repair in A-T nuclear extracts. These results suggest that ATM plays a role in maintaining genomic stability by preventing the repair of DSB from an error-prone pathway.


Asunto(s)
Ataxia Telangiectasia/genética , Núcleo Celular/metabolismo , Daño del ADN , Reparación del ADN , Proteínas Serina-Treonina Quinasas/genética , Ataxia Telangiectasia/patología , Proteínas de la Ataxia Telangiectasia Mutada , Secuencia de Bases , Proteínas de Ciclo Celular , Línea Celular Transformada , ADN , Proteínas de Unión al ADN , Fibroblastos/metabolismo , Humanos , Datos de Secuencia Molecular , Proteínas Supresoras de Tumor
15.
BJOG ; 107(9): 1176-8, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11002967

RESUMEN

Haemorrhage from pelvic veins during obstetric and gynaecological surgery is a major cause of morbidity and mortality. In a recent commentary entitled The Seven Surgeons of King's: a fable by Aesop(1), surgeons from different specialties used techniques peculiar to their own practice to treat a woman with intractable haemorrhage. Could transcatheter arterial embolisation be the 'eighth surgeon'? We describe two cases where embolisation was used to control bleeding when local surgical measures had failed and discuss the use of embolisation in obstetrics and gynaecology.


Asunto(s)
Embolización Terapéutica/métodos , Hemorragia/terapia , Pelvis/irrigación sanguínea , Complicaciones Hematológicas del Embarazo/terapia , Adulto , Colposcopía/efectos adversos , Femenino , Hemorragia/diagnóstico por imagen , Humanos , Arteria Ilíaca/diagnóstico por imagen , Embarazo , Radiografía
16.
Am J Physiol Gastrointest Liver Physiol ; 278(3): G429-37, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10712263

RESUMEN

Coupling of M(2) and M(3) muscarinic receptors to activation of mitogen-activated protein (MAP) kinases and phosphorylation of caldesmon was studied in canine colonic smooth muscle strips in which M(3) receptors were selectively inactivated by N, N-dimethyl-4-piperidinyl diphenylacetate (4-DAMP) mustard (40 nM). ACh elicited activation of extracellular signal-regulated kinase (ERK) 1, ERK2, and p38 MAP kinases in control muscles and increased phosphorylation of caldesmon (Ser(789)), a putative downstream target of MAP kinases. Alkylation of M(3) receptors with 4-DAMP had only a modest inhibitory effect on ERK activation, p38 MAP kinase activation, and caldesmon phosphorylation. Subsequent treatment with 1 microM AF-DX 116 completely prevented activation of ERK and p38 MAP kinase and prevented caldesmon phosphorylation. Caldesmon phosphorylation was blocked by the MAP kinase/ERK kinase inhibitor PD-98509 but not by the p38 MAP kinase inhibitor SB-203580. These results indicate that colonic smooth muscle M(2) receptors are coupled to ERK and p38 MAP kinases. Activation of ERK, but not p38 MAP kinases, results in phosphorylation of caldesmon in vivo, which is a novel function for M(2) receptor activation in smooth muscle.


Asunto(s)
Proteínas de Unión a Calmodulina/metabolismo , Colon/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Músculo Liso/metabolismo , Receptores Muscarínicos/metabolismo , Animales , Perros , Activación Enzimática/fisiología , Femenino , Motilidad Gastrointestinal/fisiología , Masculino , Fosforilación , Receptor Muscarínico M2 , Receptor Muscarínico M3 , Receptores Muscarínicos/fisiología
17.
Am J Physiol Cell Physiol ; 278(4): C718-26, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10751321

RESUMEN

Phosphorylation of h-caldesmon has been proposed to regulate airway smooth muscle contraction. Both extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinases phosphorylate h-caldesmon in vitro. To determine whether both enzymes phosphorylate caldesmon in vivo, phosphorylation-site-selective antibodies were used to assay phosphorylation of MAP kinase consensus sites. Stimulation of cultured tracheal smooth muscle cells with ACh or platelet-derived growth factor increased caldesmon phosphorylation at Ser789 by about twofold. Inhibiting ERK MAP kinase activation with 50 microM PD-98059 blocked agonist-induced caldesmon phosphorylation completely. Inhibiting p38 MAP kinases with 25 microM SB-203580 had no effect on ACh-induced caldesmon phosphorylation. Carbachol stimulation increased caldesmon phosphorylation at Ser789 in intact tracheal smooth muscle, which was blocked by the M(2) antagonist AF-DX 116 (1 microM). AF-DX 116 inhibited carbachol-induced isometric contraction by 15 +/- 1.4%, thus dissociating caldesmon phosphorylation from contraction. Activation of M(2) receptors leads to activation of ERK MAP kinases and phosphorylation of caldesmon with little or no functional effect on isometric force. P38 MAP kinases are also activated by muscarinic agonists, but they do not phosphorylate caldesmon in vivo.


Asunto(s)
Proteínas de Unión a Calmodulina/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Músculo Liso/metabolismo , Animales , Western Blotting , Proteínas Quinasas Dependientes de Calcio-Calmodulina/antagonistas & inhibidores , Células Cultivadas , Perros , Inhibidores Enzimáticos/farmacología , Femenino , Flavonoides/farmacología , Imidazoles/farmacología , Técnicas In Vitro , Masculino , Proteínas Quinasas Activadas por Mitógenos/antagonistas & inhibidores , Músculo Liso/citología , Fosforilación/efectos de los fármacos , Isoformas de Proteínas/metabolismo , Piridinas/farmacología , Receptores Muscarínicos/metabolismo , Transducción de Señal , Tráquea/citología , Tráquea/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos
18.
Am J Physiol ; 276(4): L549-55, 1999 04.
Artículo en Inglés | MEDLINE | ID: mdl-10198352

RESUMEN

Bronchitis, asthma, and cystic fibrosis, marked by inflammation and mucus hypersecretion, can be caused or exacerbated by airway pathogens or irritants including acrolein, an aldehyde present in tobacco smoke. To determine whether acrolein and inflammatory mediators alter mucin gene expression, steady-state mRNA levels of two airway mucins, MUC5AC and MUC5B, were measured (by RT-PCR) in human lung carcinoma cells (NCI-H292). MUC5AC mRNA levels increased after >/=0.01 nM acrolein, 10 microM prostaglandin E2 or 15-hydroxyeicosatetraenoic acid, 1.0 nM tumor necrosis factor-alpha (TNF-alpha), or 10 nM phorbol 12-myristate 13-acetate (a protein kinase C activator). In contrast, MUC5B mRNA levels, although easily detected, were unaffected by these agonists, suggesting that irritants and associated inflammatory mediators increase mucin biosynthesis by inducing MUC5AC message levels, whereas MUC5B is constitutively expressed. When transcription was inhibited, TNF-alpha exposure increased MUC5AC message half-life compared with control level, suggesting that transcript stabilization is a major mechanism controlling increased MUC5AC message levels. Together, these findings imply that irritants like acrolein can directly and indirectly (via inflammatory mediators) increase airway mucin transcripts in epithelial cells.


Asunto(s)
Acroleína/farmacología , Dinoprostona/farmacología , Regulación de la Expresión Génica/fisiología , Ácidos Hidroxieicosatetraenoicos/farmacología , Mucinas/genética , Transcripción Genética , Factor de Necrosis Tumoral alfa/farmacología , Carcinoma Mucoepidermoide , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Inflamación , Cinética , Neoplasias Pulmonares , Mucina 5AC , Mucina 5B , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Acetato de Tetradecanoilforbol/farmacología , Transcripción Genética/efectos de los fármacos , Células Tumorales Cultivadas
19.
Cell Prolif ; 31(1): 17-33, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9666816

RESUMEN

Numerous extra- and intracellular factors, including UV radiation, can initiate a programme of cell death by apoptosis. While apoptosis is commonly defined morphologically, the relationships between morphology and molecular events are not well established. To investigate these relationships in HeLa cells, eight morphometric criteria for cell proliferation and damage and 10 criteria for apoptotic phenotype were examined using light microscopy, and corroborated by ultrastructure and spectral imaging. They were identified (1) during a time course after irradiation with 0, 10 or 30 J/m2 UV-C; (2) after separation of apoptotic from normal cells on a Percoll gradient; and (3) after irradiation with UV-C plus perturbation of the apoptotic pathway by treatment with inhibitors of two caspases, ICE and CPP32. The number of cells in apoptosis increased in a dose-dependent manner after UV-C treatment. Centrifugation of irradiated cells on a Percoll gradient increased the collection of apoptotic cells tenfold. The stereotypical apoptotic phenotype, in which cells have deep cytoplasmic blebbing and highly condensed DNA, comprised only a few percent of all apoptosis, and was rarely seen in groups receiving caspase inhibitors. The most common apoptotic phenotype was a rounded cell with large spherical nucleolus and associated DNA. After treatment with UV-C plus inhibitors the apoptotic index was decreased by about 30% compared to UV-C radiation alone. These apoptotic cells had dark spherical cytoplasm with small blebs, greatly increased numbers of cytoplasmic ribosomes, abundant nucleolar material with a large separate granular component, and chromatin condensed at the nuclear membrane. Using the technique of spectral imaging, it was found that the spectrum obtained from the granular component of the nucleolus, which was elevated in apoptotic cells treated with UV-C plus inhibitors, was similar to the dense accumulation of ribosomes in the apoptotic cytoplasm. The data indicate that spectral imaging may be a useful tool for identifying and characterizing variations in the apoptotic process, and that the caspase inhibitors used here do not completely abolish UV-C induced apoptosis, but rather alter its incidence and progression.


Asunto(s)
Apoptosis , Caspasas , Cisteína Endopeptidasas/metabolismo , Inhibidores de Cisteína Proteinasa/farmacología , Rayos Ultravioleta , Clorometilcetonas de Aminoácidos/farmacología , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Caspasa 1 , Caspasa 3 , División Celular , Núcleo Celular/efectos de los fármacos , Núcleo Celular/efectos de la radiación , Citoplasma/efectos de los fármacos , Citoplasma/efectos de la radiación , Células HeLa , Humanos , Oligopéptidos/farmacología , Fenotipo , Espectroscopía Infrarroja por Transformada de Fourier
20.
Thromb Haemost ; 79(4): 741-2, 1998 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9569184

RESUMEN

Superficial venous thrombotic (SVT) events are a feature of thrombophilic abnormalities, particularly those involving the protein C pathway. We have determined the incidence of SVT associated with pregnancy and the early postpartum period in a retrospective study involving 72000 deliveries. Fourty-nine cases occurring in 47 individuals were recorded, with an overall incidence of 0.68/1000 deliveries (95% CI 0.48-0.88). None had a previous history of deep vein thrombosis or pulmonary embolism. Most events occurred in the early postpartum period (0.54/1000 deliveries). Twenty-four/fourty-seven were screened for established thrombophilic abnormalities, with only 1 abnormality detected (FV(Leiden) heterozygote). Thrombophilia may play a minor role in the aetiology of SVT associated with pregnancy, although a larger study is required to confirm this.


Asunto(s)
Complicaciones Hematológicas del Embarazo/epidemiología , Trastornos Puerperales/epidemiología , Trombofilia/epidemiología , Tromboflebitis/epidemiología , Adulto , Comorbilidad , Factor V/análisis , Factor V/genética , Femenino , Humanos , Incidencia , Embarazo , Complicaciones Hematológicas del Embarazo/etiología , Proteína C/análisis , Trastornos Puerperales/etiología , Estudios Retrospectivos , Escocia/epidemiología , Trombofilia/complicaciones , Tromboflebitis/etiología
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