Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 84
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Anaesthesia ; 76(11): 1482-1491, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-33881774

RESUMEN

Significant sleep disturbance can occur following major abdominal surgery. We aimed to evaluate the effectiveness of earplugs and eye masks in improving sleep quality and patient satisfaction, reducing nursing demands and in the incidence of delirium in patients after major abdominal surgery. We conducted a randomised controlled trial in 100 patients undergoing major abdominal surgery. We randomly allocated participants to sleep with or without earplugs and eye masks on postoperative days 1-3. The primary outcome measure was sleep quality as measured by the Richards-Campbell Sleep Questionnaire. Secondary outcomes were patient satisfaction, frequency of nursing demand and incidence of delirium measured by the Neelon and Champagne Confusion Scale. Median (IQR [range]) sleep scores were 64 (38-74 [0-100] and 60 (44-82 [18-100]) for the control and intervention groups, respectively (p = 0.310). Age and Pittsburgh Sleep Quality Index scores were found to be significant factors affecting sleep quality. There were no differences in patient satisfaction, reduction in frequency of nursing demands or incidence of delirium on postoperative days 1-3 after major abdominal surgery. The compliance rate in the intervention group was 60-65%. This study has demonstrated that the use of earplugs and eye masks did not contribute to improvements in sleep quality. Of note, sleep quality was moderate, with higher age and worse baseline sleep quality contributing to worse sleep scores. More studies are needed to investigate interventions to improve sleep quality after major abdominal surgery.


Asunto(s)
Abdomen/cirugía , Dispositivos de Protección de los Oídos , Dispositivos de Protección de los Ojos , Sueño/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Humanos , Unidades de Cuidados Intensivos , Masculino , Persona de Mediana Edad , Satisfacción del Paciente , Periodo Posoperatorio , Estudios Prospectivos , Método Simple Ciego , Encuestas y Cuestionarios
2.
Eur J Neurol ; 27(6): 959-966, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32124496

RESUMEN

BACKGROUND AND PURPOSE: This study quantified the total brain and periventricular white matter hyperintensity (WMH) burdens in patients with early Parkinson's disease (PD) and explored their associations with cardiovascular risk factors and cognitive performance. METHODS: A total of 175 non-demented patients with early PD who had undergone baseline brain magnetic resonance imaging were included. Comprehensive neurocognitive testing was conducted to identify PD with mild cognitive impairment (PD-MCI) and to evaluate performances in individual cognitive domains. Cardiovascular risk was expressed as a modified Framingham 10-year cardiovascular risk score (mFRS). RESULTS: A total of 53.7% of this early PD cohort fulfilled the diagnostic criteria for PD-MCI. An increase in mFRS was significantly associated with increases in the total brain WMH (P = 0.015) and periventricular WMH (P = 0.040) burden, independent of age and gender. The periventricular WMH burden was significantly associated with PD-MCI (P = 0.046) in early PD, independent of cardiovascular risk factors. Patients in the 5th quintile of periventricular WMH burden were 8.6 times more likely to have PD-MCI compared with patients in the 1st quintile of periventricular WMH burden (P = 0.004). However, total brain WMH burden was not associated with PD-MCI (P = 0.158). In individual cognitive domains, heavier periventricular WMH burden was associated with worse executive function and visuospatial function independent of cardiovascular risk factors. CONCLUSION: Periventricular WMHs are a useful imaging biomarker for cognitive impairment in early PD. Cardiovascular risk factors, although associated with periventricular WMHs, were unable to fully explain the association between periventricular WMHs and cognitive impairment in early PD.


Asunto(s)
Disfunción Cognitiva , Enfermedad de Parkinson , Sustancia Blanca , Disfunción Cognitiva/epidemiología , Disfunción Cognitiva/etiología , Función Ejecutiva , Humanos , Imagen por Resonancia Magnética , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/diagnóstico por imagen , Enfermedad de Parkinson/epidemiología , Sustancia Blanca/diagnóstico por imagen
3.
Eur J Neurol ; 26(3): 400-406, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30175887

RESUMEN

BACKGROUND AND PURPOSE: The aim of this study was to examine non-motor symptoms in different Parkinson's disease (PD) motor subtypes and their associations with quality of life (QoL). METHODS: A total of 132 patients with early PD with comprehensive motor examinations and non-motor symptom assessments were included. Motor subtypes were classified based on Stebbins' method. Non-motor symptoms were assessed by the Non-Motor Symptom Scale (NMSS) and validated by more comprehensive instruments, including the Pittsburgh Sleep Quality Index (PSQI) and Fatigue Severity Scale (FSS). QoL was measured by the Parkinson's Disease Questionnaire-8. RESULTS: We identified 66 patients (50%) with tremor-dominant (TD) subtype, 47 (35.6%) with postural instability and gait disorder (PIGD) subtype and 19 (14.4%) with Intermediate subtype. By comparing NMSS scores, patients with the PIGD subtype had more severe sleep impairment and fatigue (domain 2 score: 5.64 vs. 2.52, P < 0.001), urinary symptoms (domain 7 score: 6.96 vs. 3.48, P = 0.005) and overall more severe non-motor symptoms (NMSS total score: 25.89 vs. 17.27, P = 0.031), compared with patients with the TD subtype. Validation using the PSQI and FSS again suggested that patients with the PIGD subtype had independently and significantly more severe sleep impairment (PSQI score: 5.57 vs. 4.29, P = 0.020) and fatigue (FSS score: 34.81 vs. 25.85, P = 0.003) compared with patients with the TD subtype. Several non-motor symptoms had significant associations with QoL, among which sleep impairment and fatigue (P < 0.0001, partial r2 = 0.273) explained the largest proportion of QoL variability in patients with PD. CONCLUSIONS: Patients with the PIGD subtype had more severe sleep impairment, fatigue and urinary disturbance compared with patients with the TD subtype. Sleep impairment and fatigue were the most important factors affecting QoL independent of motor subtypes. Prompt identification and treatment of these non-motor symptoms may improve patients' QoL.


Asunto(s)
Fatiga , Enfermedad de Parkinson , Calidad de Vida , Trastornos del Sueño-Vigilia , Anciano , Fatiga/etiología , Fatiga/fisiopatología , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/clasificación , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/fisiopatología , Trastornos del Sueño-Vigilia/etiología , Trastornos del Sueño-Vigilia/fisiopatología
4.
Diabet Med ; 33(8): 1052-9, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-26479063

RESUMEN

AIM: Obesity is a well-established risk factor for developing Type 2 diabetes. Evidence suggests that sarcopenia, the age-related decline in muscle mass and strength, may exacerbate diabetes risk in obese individuals. The aim of this study was to determine the combined effect of obesity and low muscle strength, dynapenia, on the risk of incident Type 2 diabetes in older adults. METHODS: Participants were 5953 (1670 obese) men and women from the English Longitudinal Study of Ageing without known Type 2 diabetes at baseline and for whom handgrip strength, biochemical and other clinical data were collected. A diagnosis of Type 2 diabetes was recorded from self-reported physician diagnosis over 6 years. RESULTS: For each unit increase in grip strength, there was a reduction in diabetes risk (age-, sex- and BMI adjusted HR; 0.98; 95% CI 0.96-0.99). The risk of Type 2 diabetes was elevated in all obese participants, but was greatest in those with low handgrip strength (HR = 4.93, 95% CI 2.85, 8.53) compared with non-obese individuals with high handgrip strength. Eleven per cent of the sample met the threshold for weakness (handgrip strength: men < 26 kg; women < 16 kg) that was associated with elevated Type 2 diabetes risk in obese (HR = 3.57, 95% CI 2.04, 6.24) but not in non-obese (HR = 0.86, 95% CI, 0.44, 1.68) compared with normal/non-obese participants. CONCLUSION: Dynapenic obesity, determined by high BMI and low handgrip strength, is associated with increased risk of incident Type 2 diabetes in older people.


Asunto(s)
Diabetes Mellitus Tipo 2/epidemiología , Fuerza de la Mano , Debilidad Muscular/epidemiología , Obesidad/epidemiología , Anciano , Inglaterra/epidemiología , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Fuerza Muscular
5.
Med J Malaysia ; 70(6): 367-8, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26988214

RESUMEN

Temporal bone squamous cell carcinoma (TBSCC) is rare and poses difficulties in diagnosing, staging and management. We describe a case series with six patients who were diagnosed TBSCC, from January 2009 to June 2014, with median age of 62 years old. All patients presented with blood-stain discharge and external auditory canal mass, showing that these findings should highly alert the diagnosis of TBSCC. Three patients staged T3 and another three with T4 disease. High-resolution CT (HRCT) temporal findings were noted to be different from intraoperative findings and therefore we conclude that MRI should be done to look for middle ear involvement or other soft tissue invasion for more accurate staging. Lateral temporal bone resection (LTBR) and parotidectomy was done for four patients with or without neck dissection. Patients with positive margin, perineural invasion or parotid and glenoid involvement carry poorer prognosis and postoperative radiotherapy may improve the survival rate. One patient had successful tumor resection via piecemeal removal approach in contrast with the recommended en bloc resection shows that with negative margin achieved, piecemeal removal approach can be a good option for patients with T2-3 disease. In general, T4 tumor has dismal outcome regardless of surgery or radiotherapy given.

6.
Br J Cancer ; 110(12): 2829-36, 2014 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-24867688

RESUMEN

BACKGROUND: Screening for prostate cancer continues to generate controversy because of concerns about over-diagnosis and unnecessary treatment. We describe the rationale, design and recruitment of the Cluster randomised triAl of PSA testing for Prostate cancer (CAP) trial, a UK-wide cluster randomised controlled trial investigating the effectiveness and cost-effectiveness of prostate-specific antigen (PSA) testing. METHODS: Seven hundred and eighty-five general practitioner (GP) practices in England and Wales were randomised to a population-based PSA testing or standard care and then approached for consent to participate. In the intervention arm, men aged 50-69 years were invited to undergo PSA testing, and those diagnosed with localised prostate cancer were invited into a treatment trial. Control arm practices undertook standard UK management. All men were flagged with the Health and Social Care Information Centre for deaths and cancer registrations. The primary outcome is prostate cancer mortality at a median 10-year-follow-up. RESULTS: Among randomised practices, 271 (68%) in the intervention arm (198,114 men) and 302 (78%) in the control arm (221,929 men) consented to participate, meeting pre-specified power requirements. There was little evidence of differences between trial arms in measured baseline characteristics of the consenting GP practices (or men within those practices). CONCLUSIONS: The CAP trial successfully met its recruitment targets and will make an important contribution to international understanding of PSA-based prostate cancer screening.


Asunto(s)
Detección Precoz del Cáncer/economía , Detección Precoz del Cáncer/métodos , Selección de Paciente , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/diagnóstico , Anciano , Análisis Costo-Beneficio , Inglaterra , Médicos Generales , Humanos , Masculino , Tamizaje Masivo/economía , Tamizaje Masivo/métodos , Persona de Mediana Edad , Neoplasias de la Próstata/mortalidad , Proyectos de Investigación , Gales
7.
Med J Malaysia ; 69(6): 252-6, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25934954

RESUMEN

No abstract available.

8.
Radiography (Lond) ; 29(1): 139-144, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36370639

RESUMEN

INTRODUCTION: A service improvement project involving the vetting and protocoling of Computed Tomography (CT) scan requests by qualified CT radiographers was initiated in 2018. AIM: This study provides a comprehensive evaluation of how a radiographer-led initiative aims to ensure that the CT scan requests received by the Radiology department are clinically appropriate, which in turn will reduce interruptions to the interpretation and reporting of imaging examinations by radiologists, who might otherwise be required to attend to clinically inappropriate and wrongly protocolled CT scan requests. METHOD: Outpatient CT scan requests received from July to October 2021 were vetted and protocolled by a qualified CT-trained radiographer for parameters which included the appropriateness of the clinical indication, adequacy of patient preparation for the scan, as well as the suitability of the requested examination protocol pertaining to the need for contrast media, multiple contrast-enhanced imaging phases, and the appropriateness of the scan range. RESULTS: Poor patient preparation and insufficient or inaccurate clinical indications were the most common findings during the vetting process (71%). Out of the 64 CT scan requests with protocol errors, 77% were attributed to contrast media type errors. The odds of incorrect CT scan requests increased with the requesting clinician's rank, while there was no such significant correlation with the clinical specialty of the requesting clinician or the CT scan type. CONCLUSION: The meticulous vetting of imaging requests helps to ensure that limited imaging hardware resources are allocated to more clinically appropriate cases, correct protocols are applied to requested imaging scans, and that patients undergoing imaging are adequately prepared, thereby enhancing overall patient care. IMPLICATIONS FOR PRACTICE: Vetting of imaging requests by radiographers, who are capable to make appropriate clinical decisions related to their enhanced level of practice ensures patient safety and optimisation of Radiology resources.


Asunto(s)
Medios de Contraste , Tomografía Computarizada por Rayos X , Humanos , Singapur , Radiografía , Atención a la Salud
9.
Epidemiol Infect ; 140(3): 535-8, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21733253

RESUMEN

This study was performed to determine the prevalence, distribution of specimen sources, and antimicrobial susceptibility of the Acinetobacter calcoaceticus-Acinetobacter baumannii (Acb) species complex in Singapore. One hundred and ninety-three non-replicate Acb species complex clinical isolates were collected from six hospitals over a 1-month period in 2006. Of these, 152 (78·7%) were identified as A. baumannii, 18 (9·3%) as 'Acinetobacter pittii' [genomic species (gen. sp.) 3], and 23 (11·9%) as 'Acinetobacter nosocomialis' (gen. sp. 13TU). Carbapenem resistance was highest in A. baumannii (72·4%), followed by A. pittii (38·9%), and A. nosocomialis (34·8%). Most carbapenem-resistant A. baumannii and A. nosocomialis possessed the bla(OXA-23-like) gene whereas carbapenem-resistant A. pittii possessed the bla(OXA-58-like) gene. Two imipenem-resistant strains (A. baumannii and A. pittii) had the bla(IMP-like) gene. Representatives of carbapenem-resistant A. baumannii were related to European clones I and II.


Asunto(s)
Infecciones por Acinetobacter/epidemiología , Acinetobacter baumannii/aislamiento & purificación , Acinetobacter calcoaceticus/aislamiento & purificación , Infección Hospitalaria/epidemiología , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter calcoaceticus/efectos de los fármacos , Carbapenémicos/farmacología , Análisis por Conglomerados , Infección Hospitalaria/microbiología , Hospitales , Humanos , Tipificación Molecular , Prevalencia , Singapur/epidemiología , Resistencia betalactámica , beta-Lactamasas/genética
10.
J Cell Biol ; 141(5): 1243-53, 1998 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-9606215

RESUMEN

The death-effector domain (DED) is a critical protein interaction domain that recruits caspases into complexes with members of the TNF-receptor superfamily. Apoptosis can also be induced by expressing certain DED-containing proteins without surface receptor cross-linking. Using Green Fluorescent Protein to examine DED-containing proteins in living cells, we show that these proteins cause apoptosis by forming novel cytoplasmic filaments that recruit and activate pro-caspase zymogens. Formation of these filaments, which we term death-effector filaments, was blocked by coexpression of viral antiapoptotic DED-containing proteins, but not by bcl-2 family proteins. Thus, formation of death-effector filaments allows a regulated intracellular assembly of apoptosis-signaling complexes that can initiate or amplify apoptotic stimuli independently of receptors at the plasma membrane.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Apoptosis , Caspasas , Cisteína Endopeptidasas/metabolismo , Sitios de Unión , Proteínas Portadoras/metabolismo , Caspasa 8 , Caspasa 9 , Línea Celular , Citoplasma , Citoesqueleto , Precursores Enzimáticos/metabolismo , Proteína de Dominio de Muerte Asociada a Fas , Células HeLa , Humanos , Mitocondrias , Proteínas Recombinantes de Fusión/metabolismo , Solubilidad , Receptor fas/metabolismo
11.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 1998-2002, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31946292

RESUMEN

In radiology practices, the ultrasound-guided breast biopsy is among the most commonly performed minimally invasive procedures. However, many radiology residents in their graduate residencies are found with little or no hands-on experience with ultrasound-guided breast procedures. To enhance safety, the problem can be solved by the use of anthropomorphic training phantoms which can provide the resident with realistic ultrasound imaging and needle insertion haptic feedback. Stiffness and acoustic properties of breast tissues vary between different people. The training breast phantom should be able to possess different acoustic and mechanical properties which conform the inconsistencies found in real tissues among people. Therefore, this paper investigates the tunability of acoustic and mechanical behaviors in breast tissue mimicking materials (TMMs). Experiments of central composite design (CCD) with a center point, four corner points, and an additional four axis points were used to fit the non-linear regression model of the speed of sound. The same design of experiment approach was then used to fit the second-order response surface of the attenuation coefficient. Suitable series of tissue mimicking materials for the glandular tissue and malignant lesion were suggested. Latin hypercube design method was conducted to evaluate the main factors that affected the mechanical property (Young's modulus) of tissue mimicking materials. The results showed that the recipe of tissue mimicking materials could be customized to possess different acoustic and mechanical properties which conform the inconsistencies found in real breast tissues.


Asunto(s)
Acústica , Mama , Modelos Anatómicos , Ultrasonografía Intervencional , Mama/diagnóstico por imagen , Educación Médica , Módulo de Elasticidad , Femenino , Humanos , Fantasmas de Imagen , Ultrasonografía , Ultrasonografía Intervencional/métodos
12.
J Med Microbiol ; 67(7): 1012-1016, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29846154

RESUMEN

Our aim was to prospectively manage 22 Brucella-exposed individuals and identify the lapses in laboratory practices that lead to the exposure. The exposed individuals were risk-stratified, assessed for post-exposure prophylaxis (PEP), counselled to self-monitor symptoms and followed-up with three serology tests. Staff laboratory practices were recorded. Ten out of 13 high-risk individuals received PEP within 48 h of exposure. Compliance with PEP and serology monitoring was 90 and 96 %, respectively. No brucellosis cases were documented. A single handler manipulated the Brucella isolate on the open bench. Movement of the isolate was tracked in detail, highlighting various points of laboratory non-conformance. Early PEP intervention is effective in preventing acquired brucellosis. Our pragmatic post-exposure management achieved high PEP and serology compliance. We experience first-hand how regular staff engagement motivated PEP adherence and interval blood sampling attendance. The enforcement of practical strategies and safety practices was also implemented without compromising our laboratory processing times.


Asunto(s)
Accidentes de Trabajo , Brucella melitensis/aislamiento & purificación , Brucelosis/prevención & control , Exposición Profesional , Profilaxis Posexposición/métodos , Anciano , Brucelosis/diagnóstico , Femenino , Adhesión a Directriz , Humanos , Control de Infecciones/métodos
13.
Clin Microbiol Infect ; 13(5): 541-4, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17371537

RESUMEN

In total, 172 isolates of Enterobacteriaceae, Acinetobacter spp., Pseudomonas aeruginosa and Stenotrophomonas maltophilia were tested for susceptibility to colistin by agar dilution, Etest and the Vitek 2 system. Isolates with a colistin MIC < or =2 mg/L were considered to be susceptible. Fifty-four (31%) Gram-negative isolates were resistant to colistin. Categorical agreement between agar dilution and Etest was 87%, and between agar dilution and Vitek 2 was 82%. Based on the data obtained, the Vitek 2 system was unreliable for detecting colistin resistance, and results obtained by Etest may require confirmation by a standard MIC susceptibility testing method.


Asunto(s)
Antibacterianos/farmacología , Colistina/farmacología , Pruebas de Sensibilidad Microbiana/instrumentación , Pruebas de Sensibilidad Microbiana/métodos , Recuento de Colonia Microbiana , Enterobacteriaceae/efectos de los fármacos , Bacilos y Cocos Aerobios Gramnegativos/efectos de los fármacos , Humanos
14.
Mol Cell Biol ; 8(4): 1790-4, 1988 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-3380097

RESUMEN

HuT-14T is a highly tumorigenic fibroblast cell line which exhibits a reduced steady-state level of beta-actin due to coding mutations in one of two beta-actin alleles. The normal rate of total actin synthesis could be restored in some clones of cells following transfection of the functional beta-actin gene but not following transfection of the functional gamma-actin gene. In gamma-actin gene-transfected substrains that have increased rates of gamma-actin synthesis, beta-actin synthesis is further reduced in a manner consistent with an autoregulatory mechanism, resulting in abnormal ratios of actin isoforms. Thus, both beta- and gamma-actin proteins can apparently regulate the synthesis of their coexpressed isoforms. In addition, decreased synthesis of normal beta-actin seems to correlate with a concomitant down-regulation of tropomyosin isoforms.


Asunto(s)
Actinas/genética , Citoesqueleto/metabolismo , Genes , Proteínas de Microfilamentos/genética , Transfección , Actinas/biosíntesis , Línea Celular , Regulación de la Expresión Génica , Humanos , Proteínas de Microfilamentos/biosíntesis , Mutación , Tropomiosina/biosíntesis , Tropomiosina/genética
15.
Mol Cell Biol ; 7(7): 2457-66, 1987 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-3614198

RESUMEN

Two different mutant human beta-actin genes have been introduced into normal diploid human (KD) fibroblasts and their immortalized derivative cell line, HuT-12, to assess the impact of an abnormal cytoskeletal protein on cellular phenotypes such as morphology, growth characteristics, and properties relating to the neoplastic phenotype. A mutant beta-actin containing a single mutation (Gly-244----Asp-244) was stable and was incorporated into cytoskeletal stress fibers. Transfected KD cells which expressed the stable mutant beta-actin in excess of normal beta-actin were morphologically altered. In contrast, a second mutant beta-actin gene containing two additional mutations (Gly-36----Glu-36 and Glu-83----Asp-83, as well as Gly-244----Asp-244) did not alter cell morphology when expressed at high levels in transfected cells, but the protein was labile and did not accumulate in stress fibers. In both KD and HuT-12 cells, endogenous beta- and gamma-actin decreased in response to high-level expression of the stable mutant beta-actin, in a manner consistent with autoregulatory feedback of actin concentrations. Since the percent decreases in the endogenous beta- and gamma-actins were equal, the ratio of net beta-actin (mutant plus normal) to gamma-actin was significantly increased in the transfected cells. Antisera capable of distinguishing the mutant from the normal epitope revealed that the mutant beta-actin accumulated in stress fibers but did not participate in the formation of the actin filament-rich perinuclear network. These observations suggest that different intracellular locations differentially incorporate actin into cytoskeletal microfilaments. The dramatic impact on cell morphology and on beta-actin/gamma-actin ratios in the transfected diploid KD cells may be related to the acquisition of some of the characteristics of cells that underwent the neoplastic transformation event that originally led to the appearance of the beta-actin mutations.


Asunto(s)
Actinas/genética , Mutación , Actinas/metabolismo , Alelos , División Celular , Línea Celular , Citoesqueleto/metabolismo , Citoesqueleto/ultraestructura , Regulación de la Expresión Génica , Genes , Homeostasis , Humanos , Fenotipo , Transfección
16.
Mol Cell Biol ; 7(7): 2467-76, 1987 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-3614199

RESUMEN

Mutant human beta-actin genes were introduced into normal human (KD) fibroblasts and the derivative cell line HuT-12, which is immortalized but nontumorigenic, to test their ability to promote conversion to the tumorigenic state. Transfected substrains of HuT-12 fibroblasts that expressed abundant levels of mutant beta-actin (Gly-244----Asp-244) produced subcutaneous tumors in athymic mice after long latent periods (1.5 to 3 months). However, transfected substrains of KD fibroblasts retained their normal finite life span in culture and consequently were incapable of producing tumors. Substrains of HuT-12 cells transfected with the wild-type beta-actin gene and some transfected strains that expressed low or undetectable levels of mutant beta-actin did not produce tumors. Cell lines derived from transfectant cell tumors always exhibited elevated synthesis of the mutant beta-actin, ranging from 145 to 476% of the level expressed by the transfected cells that were inoculated to form the tumor. In general, primary transfectant cells that expressed the highest levels of mutant beta-actin were more tumorigenic than strains that expressed lower levels. The tumor-derived strains were stable in tumorigenicity and produced tumors with shortened latent periods of only 2 to 4 weeks. These findings imply that the primary transfectant strains develop subpopulations of cells that are selected to form tumors because of their elevated rate of exogenous mutant beta-actin synthesis. Actin synthesis and accumulation of gamma-actin mRNA from the endogenous beta- and gamma-actin genes were diminished in tumor-derived strains, apparently to compensate for elevated mutant beta-actin synthesis and maintain the normal cellular concentration of actin. Synthesis of the transformation-sensitive tropomyosin isoforms was decreased along with mutant beta-actin expression. Such modulations in tropomyosin synthesis are characteristically seen in transformation of avian, rodent, and human fibroblasts. Our results suggest that this mutant beta-actin contributes to the neoplastic phenotype of immortalized human fibroblasts by imposing a cytoarchitectural defect and inducing abnormal expression of cytoskeletal tropomyosins.


Asunto(s)
Actinas/genética , Transformación Celular Neoplásica , Mutación , Actinas/metabolismo , Animales , Línea Celular , Regulación de la Expresión Génica , Homeostasis , Humanos , Ratones , Ratones Desnudos , Neoplasias Experimentales/genética , Oncogenes , Fenotipo , Transfección , Tropomiosina/metabolismo
17.
Mol Cell Biol ; 4(10): 1961-9, 1984 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-6095033

RESUMEN

There are more than 20 beta-actin-specific sequences in the human genome, many of which are pseudogenes. To facilitate the isolation of potentially functional beta-actin genes, we used the new method of B. Seed (Nucleic Acids Res. 11:2427-2446, 1983) for selecting genomic clones by homologous recombination. A derivative of the pi VX miniplasmid, pi AN7 beta 1, was constructed by insertion of the 600-base-pair 3' untranslated region of the beta-actin mRNA expressed in human fibroblasts. Five clones containing beta-actin sequences were selected from an amplified human fetal gene library by homologous recombination between library phage and the miniplasmid. One of these clones contained a complete beta-actin gene with a coding sequence identical to that determined for the mRNA of human fibroblasts. A DNA fragment consisting of mostly intervening sequences from this gene was then used to identify 13 independent recombinant copies of the analogous gene from two specially constructed gene libraries, each containing one of the two types of mutant beta-actin genes found in a line of neoplastic human fibroblasts. The amino acid and nucleotide sequences encoded by the unmutated gene predict that a guanine-to-adenine transition is responsible for the glycine-to-aspartic acid mutation at codon 244 and would also result in the loss of a HaeIII site. Detection of this HaeIII polymorphism among the fibroblast-derived clones verified the identity of the beta-actin gene expressed in human fibroblasts.


Asunto(s)
Actinas/genética , Clonación Molecular , Mutación , Alelos , ADN/análisis , ADN/aislamiento & purificación , Enzimas de Restricción del ADN/metabolismo , Desoxirribonucleasa EcoRI , Electroforesis en Gel de Poliacrilamida , Escherichia coli , Humanos , Hibridación de Ácido Nucleico , Plásmidos , Polimorfismo Genético , Recombinación Genética
18.
Mol Cell Biol ; 5(10): 2720-32, 1985 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3837182

RESUMEN

We have assigned six members of the human beta-actin multigene family to specific human chromosomes. The functional gene, ACTB, is located on human chromosome 7, and the other assigned beta-actin-related sequences are dispersed over at least four different chromosomes including one locus assigned to the X chromosome. Using intervening sequence probes, we showed that the functional gene is single copy and that all of the other beta-actin related sequences are recently generated in evolution and are probably processed pseudogenes. The entire nucleotide sequence of the functional gene has been determined and is identical to cDNA clones in the coding and 5' untranslated regions. We have previously reported that the 3' untranslated region is well conserved between humans and rats (Ponte et al., Nucleic Acids Res. 12:1687-1696, 1984). Now we report that four additional noncoding regions are evolutionarily conserved, including segments of the 5' flanking region, 5' untranslated region, and, surprisingly, intervening sequences I and III. These conserved sequences, especially those found in the introns, suggest a role for internal sequences in the regulation of beta-actin gene expression.


Asunto(s)
Actinas/genética , Animales , Secuencia de Bases , Pollos , Mapeo Cromosómico , ADN/genética , Elementos de Facilitación Genéticos , Genes , Humanos , Conformación de Ácido Nucleico , Regiones Promotoras Genéticas , ARN Mensajero/genética , Homología de Secuencia de Ácido Nucleico
19.
Mol Cell Biol ; 15(7): 3654-63, 1995 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-7791772

RESUMEN

Ectopic overexpression of v-H-Ras protein in NIH 3T3 cells resulted in cellular transformation and an acceleration of G1 progression of these cells. A shortened G1 phase was found to be associated with an increased level of cyclin D1 but not cyclin E protein. Using an antisense blocking method, reduced synthesis of cyclin D1 in v-H-Ras transformants resulted in a slower G1 progression rate of these cells. Although constitutive overexpression of cyclin D1 in NIH 3T3 cells accelerated G1 progression, cells remained untransformed. Furthermore, inhibition of cyclin D1 synthesis greatly impaired the soft-agar cloning efficiency of v-H-Ras transformants. These results suggest that increased expression of cyclin D1 is necessary but not sufficient for the transforming activity of v-H-Ras. Similar effect on cell cycle progression was also observed in Raf-transformed cells. In addition to cyclin D1, cyclin E protein was found to be elevated in Src transformants. This may account for the further shortening of the G1 phase of these cells. Activation of an additional Ras-independent pathway was suggested to be responsible for the further acceleration of the G1 phase in Src transformants.


Asunto(s)
Transformación Celular Neoplásica , Ciclinas/biosíntesis , Interfase/fisiología , Proteínas Oncogénicas/biosíntesis , Proteínas Proto-Oncogénicas p21(ras)/biosíntesis , Células 3T3 , Animales , Northern Blotting , Células Clonales , Ciclina D1 , Ciclinas/genética , Citometría de Flujo , Fase G1/fisiología , Immunoblotting , Ratones , Proteína Oncogénica pp60(v-src)/biosíntesis , Proteína Oncogénica pp60(v-src)/genética , Proteínas Oncogénicas/genética , Proteínas Oncogénicas v-raf , Proteínas Proto-Oncogénicas p21(ras)/genética , ARN Mensajero/análisis , Proteínas Oncogénicas de Retroviridae/biosíntesis , Proteínas Oncogénicas de Retroviridae/genética , Fase S/fisiología , Factores de Tiempo , Transformación Genética
20.
Int J Oral Maxillofac Surg ; 35(4): 324-31, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16356683

RESUMEN

Tumour thickness and the status of resection margins are of prognostic significance in the treatment of oral cancer. In a single blind prospective study, 14 patients with biopsy proven oral squamous cell carcinoma had intraoral ultrasound imaging done preoperatively to measure tumour thickness, and intraoperatively to measure the deep surgical margin half way during resection. The cut surface was demonstrated on ultrasound by placing a metal, ultrasound-reflective, retractor into the surgical cut. The ultrasound measurements were compared to the subsequent histological measurements. Using the threshold of 5mm as indicator of margin clearance, there was agreement in 10 out of 14 cases between ultrasound and histology. Ultrasound detection of close surgical margins had a sensitivity of 83% and a specificity of 63%. For preoperative tumour thickness measurement, ultrasound imaging showed a high degree of correlation with histology (Pearson correlation coefficient=0.95, P<0.01). This original paper demonstrates that high resolution ultrasound imaging applied intraorally is a reliable tool in objectively assessing both the tumour thickness and the surgical margin clearance at the time of surgery.


Asunto(s)
Carcinoma de Células Escamosas/diagnóstico por imagen , Neoplasias de la Boca/diagnóstico por imagen , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/cirugía , Métodos Epidemiológicos , Humanos , Neoplasias de la Boca/patología , Neoplasias de la Boca/cirugía , Ultrasonografía
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA