Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 29
Filtrar
Más filtros

Base de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Sci Adv ; 9(17): eade2675, 2023 04 28.
Artículo en Inglés | MEDLINE | ID: mdl-37115922

RESUMEN

Glioma is a rare brain tumor with a poor prognosis. Familial glioma is a subset of glioma with a strong genetic predisposition that accounts for approximately 5% of glioma cases. We performed whole-genome sequencing on an exploratory cohort of 203 individuals from 189 families with a history of familial glioma and an additional validation cohort of 122 individuals from 115 families. We found significant enrichment of rare deleterious variants of seven genes in both cohorts, and the most significantly enriched gene was HERC2 (P = 0.0006). Furthermore, we identified rare noncoding variants in both cohorts that were predicted to affect transcription factor binding sites or cause cryptic splicing. Last, we selected a subset of discovered genes for validation by CRISPR knockdown screening and found that DMBT1, HP1BP3, and ZCH7B3 have profound impacts on proliferation. This study performs comprehensive surveillance of the genomic landscape of familial glioma.


Asunto(s)
Neoplasias Encefálicas , Glioma , Humanos , Glioma/genética , Glioma/patología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Genómica , Predisposición Genética a la Enfermedad , Secuenciación Completa del Genoma , Proteínas de Unión al Calcio/genética , Proteínas de Unión al ADN/genética , Proteínas Supresoras de Tumor/genética
2.
Eur Respir J ; 60(5)2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35728977

RESUMEN

BACKGROUND: Bronchiectasis can result from infectious, genetic, immunological and allergic causes. 60-80% of cases are idiopathic, but a well-recognised genetic cause is the motile ciliopathy, primary ciliary dyskinesia (PCD). Diagnosis of PCD has management implications including addressing comorbidities, implementing genetic and fertility counselling and future access to PCD-specific treatments. Diagnostic testing can be complex; however, PCD genetic testing is moving rapidly from research into clinical diagnostics and would confirm the cause of bronchiectasis. METHODS: This observational study used genetic data from severe bronchiectasis patients recruited to the UK 100,000 Genomes Project and patients referred for gene panel testing within a tertiary respiratory hospital. Patients referred for genetic testing due to clinical suspicion of PCD were excluded from both analyses. Data were accessed from the British Thoracic Society audit, to investigate whether motile ciliopathies are underdiagnosed in people with bronchiectasis in the UK. RESULTS: Pathogenic or likely pathogenic variants were identified in motile ciliopathy genes in 17 (12%) out of 142 individuals by whole-genome sequencing. Similarly, in a single centre with access to pathological diagnostic facilities, 5-10% of patients received a PCD diagnosis by gene panel, often linked to normal/inconclusive nasal nitric oxide and cilia functional test results. In 4898 audited patients with bronchiectasis, <2% were tested for PCD and <1% received genetic testing. CONCLUSIONS: PCD is underdiagnosed as a cause of bronchiectasis. Increased uptake of genetic testing may help to identify bronchiectasis due to motile ciliopathies and ensure appropriate management.


Asunto(s)
Bronquiectasia , Trastornos de la Motilidad Ciliar , Ciliopatías , Síndrome de Kartagener , Humanos , Mutación , Bronquiectasia/diagnóstico , Bronquiectasia/genética , Cilios , Trastornos de la Motilidad Ciliar/diagnóstico , Trastornos de la Motilidad Ciliar/genética , Ciliopatías/complicaciones , Síndrome de Kartagener/diagnóstico , Síndrome de Kartagener/genética
3.
BJS Open ; 2(4): 162-174, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30079385

RESUMEN

BACKGROUND: The clinical effectiveness of treating ipsilateral multifocal (MF) and multicentric (MC) breast cancers using breast-conserving surgery (BCS) compared with the standard of mastectomy is uncertain. Inconsistencies relate to definitions, incidence, staging and intertumoral heterogeneity. The primary aim of this systematic review was to compare clinical outcomes after BCS versus mastectomy for MF and MC cancers, collectively defined as multiple ipsilateral breast cancers (MIBC). METHODS: Comprehensive electronic searches were undertaken to identify complete papers published in English between May 1988 and July 2015, primarily comparing clinical outcomes of BCS and mastectomy for MIBC. All study designs were included, and studies were appraised critically using the Newcastle-Ottawa Scale. The characteristics and results of identified studies were summarized. RESULTS: Twenty-four retrospective studies were included in the review: 17 comparative studies and seven case series. They included 3537 women with MIBC undergoing BCS; breast cancers were defined as MF in 2677 women, MC in 292, and reported as MIBC in 568. Six studies evaluated MIBC treated by BCS or mastectomy, with locoregional recurrence (LRR) rates of 2-23 per cent after BCS at median follow-up of 59·5 (i.q.r. 56-81) months. BCS and mastectomy showed apparently equivalent rates of LRR (risk ratio 0·94, 95 per cent c.i. 0·65 to 1·36). Thirteen studies compared BCS in women with MIBC versus those with unifocal cancers, reporting LRR rates of 2-40 per cent after BCS at a median follow-up of 64 (i.q.r. 57-73) months. One high-quality study reported 10-year actuarial LRR rates of 5·5 per cent for BCS in 300 women versus 6·5 per cent for mastectomy among 887 women. CONCLUSION: The available studies were mainly of moderate quality, historical and underpowered, with limited follow-up and biased case selection favouring BCS rather than mastectomy for low-risk patients. The evidence was inconclusive, weakening support for the St Gallen consensus and supporting a future randomized trial.

4.
J Neuroendocrinol ; 28(12)2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27805753

RESUMEN

Dehydroepiandrosterone (DHEA) is a testosterone/oestrogen precursor and known modulator of vertebrate aggression. Male song sparrows (Melospiza melodia morphna) show high aggression during breeding and nonbreeding life-history stages when circulating DHEA levels are high, and low aggression during molt when DHEA levels are low. We previously showed that androgen receptor and aromatase mRNA expression are higher during breeding and/or nonbreeding in brain regions associated with reproductive and aggressive behaviour, although the potential role of DHEA in mediating these seasonal changes remained unclear. In the present study, nonbreeding male song sparrows were captured and held in the laboratory under short days (8 : 16 h light/dark cycle) and implanted with s.c. DHEA-filled or empty (control) implants for 14 days. DHEA implants increased aggression in a laboratory-based simulated territorial intrusion. Brains of DHEA-implanted birds showed higher aromatase mRNA expression in the preoptic area (POA) and higher androgen receptor mRNA expression in the periventricular nucleus of the medial striatum (pvMSt) and ventromedial nucleus of the hypothalamus. The DHEA-induced increases in aromatase expression in the POA and androgen receptor expression in the pvMSt are consistent with previously reported seasonal increases in these markers associated with naturally elevated DHEA levels. This suggests that DHEA facilitates seasonal increases in aggression in nonbreeding male song sparrows by up-regulating steroid signalling/synthesis machinery in a brain region-specific fashion.


Asunto(s)
Agresión/fisiología , Aromatasa/metabolismo , Proteínas Aviares/fisiología , Encéfalo/fisiología , Deshidroepiandrosterona/fisiología , Receptores Androgénicos/metabolismo , Gorriones/fisiología , Animales , Masculino , ARN Mensajero/metabolismo
6.
Arch Dis Child Fetal Neonatal Ed ; 96(1): F45-52, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20876595

RESUMEN

OBJECTIVES: To evaluate the effects of indomethacin or ibuprofen compared with placebo on closure, morbidity and mortality in preterm infants <37 weeks' gestation with echocardiographically and/or clinically important patent ductus arteriosus (PDA) at >24 h of life. DATA SOURCES: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL, Cochrane Library, clinicaltrials.gov, controlled-trials.com, American Pediatric and European Paediatric Research Societies and Effective Care of the Newborn Infant. REVIEW METHODS: Systematic review with network meta-analysis of randomised studies comparing intravenous indomethacin, ibuprofen or placebo for PDA in preterm infants at >24 h of life. RESULTS: Ten trials compared intravenous indomethacin versus intravenous ibuprofen, nine intravenous indomethacin versus placebo and one intravenous ibuprofen versus placebo. Both intravenous indomethacin (pooled RR 2.39 (95% CI 2.05 to 2.78)) and intravenous ibuprofen (RR 2.40 (95% CI 2.03 to 2.84)) closed a PDA more effectively than placebo. Intravenous ibuprofen was associated with approximately 30% greater risk of chronic lung disease than intravenous indomethacin (RR 1.28 (95% CI 1.03 to 1.60)) or placebo (RR 1.29 (95% CI 0.99 to 1.70)). Differences in risk or benefit were not significant between any combination of intravenous indomethacin, intravenous ibuprofen or placebo groups for intraventricular haemorrhage, necrotising enterocolitis and death. Reporting on neurological outcomes was insufficient for pooling. CONCLUSIONS: Intravenous indomethacin or ibuprofen administered to preterm infants for PDA at >24 h of life promoted ductal closure, but other short-term benefits were not seen. Treatment with intravenous ibuprofen may increase the risk of chronic lung disease. Good-quality evidence of treatment effect on morbidity, mortality and improved neurodevelopment is urgently needed.


Asunto(s)
Fármacos Cardiovasculares/uso terapéutico , Conducto Arterioso Permeable/tratamiento farmacológico , Ibuprofeno/uso terapéutico , Indometacina/uso terapéutico , Enfermedades del Prematuro/tratamiento farmacológico , Inhibidores de la Ciclooxigenasa/uso terapéutico , Femenino , Humanos , Recién Nacido , Recien Nacido Prematuro , Masculino , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del Tratamiento
7.
Cell Death Differ ; 15(11): 1752-9, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18617895

RESUMEN

Yes-associated protein (YAP) has been shown to positively regulate p53 family members and to be negatively regulated by the AKT proto-oncogene product in promoting apoptosis. On the basis of this function and its location at 11q22.2, a site of frequent loss of heterozygosity (LOH) in breast cancer, we investigated whether YAP is a tumor suppressor in breast. Examination of tumors by immunohistochemistry demonstrated significant loss of YAP protein. LOH analysis revealed that protein loss correlates with specific deletion of the YAP gene locus. Functionally, short hairpin RNA knockdown of YAP in breast cell lines suppressed anoikis, increased migration and invasiveness, inhibited the response to taxol and enhanced tumor growth in nude mice. This is the first report indicating YAP as a tumor suppressor, revealing its decreased expression in breast cancer as well as demonstrating the functional implications of YAP loss in several aspects of cancer signaling.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Mama/metabolismo , Fosfoproteínas/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Anoicis/efectos de los fármacos , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Citoprotección/efectos de los fármacos , Resistencia a Medicamentos/efectos de los fármacos , Epitelio/efectos de los fármacos , Epitelio/metabolismo , Eliminación de Gen , Silenciador del Gen/efectos de los fármacos , Humanos , Ratones , Ratones Desnudos , Invasividad Neoplásica , Paclitaxel/farmacología , Fosfoproteínas/genética , Proto-Oncogenes Mas , Factores de Transcripción , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas Señalizadoras YAP
8.
J Pathol ; 215(2): 184-94, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18393367

RESUMEN

Bladder cancer is the fifth most common malignancy in the UK. Clinically, the most important process in determining prognosis is the development of invasion, initially of the lamina propria and then beyond as these transitional cell carcinomas (TCCs) progress from stage pT1 to stages T2+. Cadherins and catenins are the main mediators of cell-cell interactions in epithelial tissues, and loss of membranous E-cadherin immunoreactivity is strongly correlated with high grade, advanced stage and poor prognosis in bladder cancer and other malignancies. However, the role of P-cadherin is yet to be fully elucidated in bladder TCC. The objectives of this study were to establish how the expression of cadherins and catenins determines clinical and in vitro behaviour in bladder TCC. Utilizing immunohistochemistry, immunofluorescence and western blotting, we demonstrated a significant reduction in the expression of E-cadherin and beta-catenin as grade and stage of bladder TCC progress, accompanied by a significant increase in P-cadherin expression (all p < 0.05, Pearson's chi2 test). Increased P-cadherin expression was also associated with a significantly worse bladder cancer-specific survival (log rank p = 0.008), with Cox regression showing P-cadherin to be an independent prognostic factor. Utilizing a variety of tissue culture models in a range of functional studies, we demonstrated that P-cadherin mediates defective cell-cell adhesion and enhances anchorage-independent growth. The results provide evidence that increased P-cadherin expression promotes a more malignant and invasive phenotype of bladder cancer, and appears to have a novel role late in the disease.


Asunto(s)
Biomarcadores de Tumor/análisis , Cadherinas/metabolismo , Carcinoma de Células Transicionales/metabolismo , Cateninas/metabolismo , Neoplasias de la Vejiga Urinaria/metabolismo , Western Blotting/métodos , Cadherinas/análisis , Carcinoma de Células Transicionales/química , Carcinoma de Células Transicionales/patología , Cateninas/análisis , Humanos , Inmunohistoquímica , Pronóstico , Modelos de Riesgos Proporcionales , Análisis de Supervivencia , Neoplasias de la Vejiga Urinaria/química , Neoplasias de la Vejiga Urinaria/patología , beta Catenina/análisis
9.
Pharmacogenomics ; 7(6): 935-42, 2006 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16981851

RESUMEN

Women of African descent have a lower incidence of breast cancer than their white counterparts; however, the overall age-adjusted breast cancer mortality rates are higher. They also present at a younger age, and have more advanced disease that exhibits poor prognostic features including significantly larger tumors of higher grade, higher rates of estrogen receptor and progesterone receptor negativity and a higher rate of p53 mutations and HRAS1 proto-oncogene expression, all of which confer a poor prognosis. While there are many possible contributory factors to the discrepancies in outcome in women of African descent, there is no satisfactory explanation as to why women of African origin tend to present at a younger age with hormone receptor-negative tumors and more adverse prognostic features.


Asunto(s)
Neoplasias de la Mama/genética , Etnicidad/genética , Negro o Afroamericano/genética , Población Negra/genética , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/metabolismo , Femenino , Genes BRCA1 , Genes BRCA2 , Genes p53 , Genes ras , Humanos , Mutación , Farmacogenética , Pronóstico , Proto-Oncogenes Mas , Receptores de Estrógenos/metabolismo , Receptores de Progesterona/metabolismo , Población Blanca/genética
10.
Ann Hum Biol ; 30(6): 678-92, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-14675909

RESUMEN

AIM: Historical accounts of the mining population in County Durham, UK, offer two persistent representations of demographic behaviour--substantial mobility and occupational endogamy--which would influence the distribution of genes in the population. The aim of this paper is to test these predictions against 19th-century demographic data, comparing miners with other contemporary occupations. SUBJECTS AND METHODS: Four parishes in County Durham yielded data on 3653 birthplace-residence distances, calculated from locations recorded in the 1851 census enumerators' books, and on occupational endogamy and exogamy for 3784 marriages recorded in the Anglican registers, 1834-76. Endogamy was analysed by log-linear models and odds ratios. RESULTS: Median migration distances were similar in the miners and other occupations, though the proportion of migrants among the miners (99.7%) was higher than agricultural (87.0%) and general labourers (91%). Endogamy in the miners (76%) was higher than in other populations (maximum 39%), but further analysis showed that the miners' tendency to marry women from the same occupational background was less than among agricultural labourers or professional men. CONCLUSION: Predictions of high migration rate and endogamy among the mining populations were upheld, but there was little evidence that the behaviour of the miners differed from other occupational groups.


Asunto(s)
Minas de Carbón/historia , Demografía , Sistema de Registros , Emigración e Inmigración/historia , Femenino , Historia del Siglo XIX , Humanos , Masculino , Matrimonio/historia , Reino Unido
11.
J Immunol Methods ; 254(1-2): 85-98, 2001 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-11406155

RESUMEN

We describe here the development and characterization of the CyQUANT cell proliferation assay, a highly sensitive, fluorescence-based microplate assay for determining numbers of cultured cells. The assay employs CyQUANT GR dye, which produces a large fluorescence enhancement upon binding to cellular nucleic acids that can be measured using standard fluorescein excitation and emission wavelengths. The fluorescence emission of the dye-nucleic acid complexes correlated linearly with cell number over a large range using a wide variety of cell types. Under the recommended assay conditions, standard curves were linear (r(2)>0.995), detecting as few as 10-50 cells and as many as 25,000-50,000 cells with a single dye concentration, depending on cell type. Increasing the dye concentration extended the linear range of the assay to 100,000-250,000 cells. Results of cell proliferation and growth inhibition studies with the assay were similar to those obtained in published studies using other standard assays. CyQUANT assay measurements of serum-stimulated cell proliferation correlated well with measurements made using [3H]-thymidine. Also, the assay was used to analyze cellular DNA or RNA content, with the addition of a nuclease digestion step to the protocol. The assay procedure is simple and convenient, with no wash steps, and is readily amenable to automation.


Asunto(s)
Recuento de Células/métodos , Colorantes Fluorescentes , Células 3T3 , Animales , División Celular , Células Cultivadas , Cianuros , ADN/análisis , Perros , Fluorescencia , Humanos , Modelos Lineales , Ratones , ARN/análisis , Sensibilidad y Especificidad , Células Tumorales Cultivadas
12.
Anal Biochem ; 293(1): 8-15, 2001 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-11373072

RESUMEN

We have developed a simple, sensitive, fluorescence microplate-based assay for tumor necrosis factor (TNF) biological activity. The assay employs SYTOX Green nucleic acid stain to detect TNF-induced cell necrosis in actinomycin D sensitized cultured cell lines. SYTOX Green stain is a cationic unsymmetrical cyanine dye that is excluded from live cells but can readily penetrate cells with compromised cell membranes. Upon binding to cellular nucleic acids, the dye exhibits a large enhancement in fluorescence, which is monitored at fluorescein wavelengths. We detected 2.5 pg/mL and quantitated 25-500 pg/mL recombinant murine (rm) and recombinant human (rh) TNF-alpha, using mouse fibroblast-derived WEHI 164, WEHI 13var, and L929 cell lines. The procedure can also be used to detect agents that modulate TNF activity. We demonstrated complete inhibition of rhTNF-alpha using monoclonal anti-human TNF-alpha antibody and determined that approximately 20 ng/mL antibody was sufficient to neutralize 50% of the biological activity of 250 pg/mL rhTNF-alpha in these cell lines. Reagents are added in a single step, followed by a 6- to 8-h incubation period, during which the cytokine exhibits its effects. There are no wash steps, and the assay is readily amenable to automation and high-throughput screening procedures.


Asunto(s)
Bioensayo/métodos , Fluorescencia , Colorantes Fluorescentes , Proteínas Recombinantes/análisis , Factor de Necrosis Tumoral alfa/análisis , Animales , Recuento de Células , Línea Celular , Medios de Cultivo , Humanos , Inmunoglobulina G , Indicadores y Reactivos , Compuestos Orgánicos , Propidio , Proteínas Recombinantes/toxicidad , Factor de Necrosis Tumoral alfa/toxicidad
13.
Cell ; 104(6): 913-22, 2001 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-11290328

RESUMEN

In the absence of an overt cytoskeleton, the external cell wall of bacteria has traditionally been assumed to be the primary determinant of cell shape. In the Gram-positive bacterium Bacillus subtilis, two related genes, mreB and mbl, were shown to be required for different aspects of cell morphogenesis. Subcellular localization of the MreB and Mbl proteins revealed that each forms a distinct kind of filamentous helical structure lying close to the cell surface. The distribution of the proteins in different species of bacteria, and the similarity of their sequence to eukaryotic actins, suggest that the MreB-like proteins have a cytoskeletal, actin-like role in bacterial cell morphogenesis.


Asunto(s)
Actinas/genética , Actinas/metabolismo , Bacillus subtilis/citología , Bacillus subtilis/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas del Citoesqueleto , Proteínas de Escherichia coli , Actinas/química , Secuencia de Aminoácidos , Animales , Bacillus subtilis/crecimiento & desarrollo , Bacterias/genética , Proteínas Bacterianas/química , Genes Bacterianos , Humanos , Datos de Secuencia Molecular , Morfogénesis , Alineación de Secuencia , Homología de Secuencia de Aminoácido
14.
Anal Biochem ; 268(2): 278-88, 1999 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-10075818

RESUMEN

The highest sensitivity nucleic acid gel stains developed to date are optimally excited using short-wavelength ultraviolet or visible light. This is a disadvantage for laboratories equipped only with 306- or 312-nm UV transilluminators. We have developed a new unsymmetrical cyanine dye that overcomes this problem. This new dye, SYBR Gold nucleic acid gel stain, has two fluorescence excitation maxima when bound to DNA, one centered at approximately 300 nm and one at approximately 495 nm. We found that when used with 300-nm transillumination and Polaroid black-and-white photography, SYBR Gold stain is more sensitive than ethidium bromide, SYBR Green I stain, and SYBR Green II stain for detecting double-stranded DNA, single-stranded DNA, and RNA. SYBR Gold stain's superior sensitivity is due to the high fluorescence quantum yield of the dye-nucleic acid complexes ( approximately 0.7), the dye's large fluorescence enhancement upon binding to nucleic acids ( approximately 1000-fold), and its capacity to more fully penetrate gels than do the SYBR Green gel stains. We found that SYBR Gold stain is as sensitive as silver staining for detecting DNA-with a single-step staining procedure. Finally, we found that staining nucleic acids with SYBR Gold stain does not interfere with subsequent molecular biology protocols.


Asunto(s)
Colorantes Fluorescentes , Ácidos Nucleicos/análisis , Compuestos Orgánicos , Coloración y Etiquetado/métodos , Animales , Benzotiazoles , Bovinos , ADN/análisis , ADN Viral/análisis , Diaminas , Etidio , Estudios de Evaluación como Asunto , Fluoresceína , Ratones , Fotograbar , Quinolinas , ARN/análisis , Sensibilidad y Especificidad , Coloración y Etiquetado/estadística & datos numéricos , Rayos Ultravioleta
15.
Anal Biochem ; 265(2): 368-74, 1998 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-9882416

RESUMEN

We describe the development of a sensitive fluorescence-based solution assay for RNA using a new dye, RiboGreen RNA quantitation reagent. RiboGreen reagent exhibits >1000-fold fluorescence enhancement and high quantum yield (0.65) upon binding nucleic acids, with excitation and emission maxima near those of fluorescein. Unbound dye is essentially nonfluorescent and has a large extinction coefficient (67,000 cm-1 M-1). The RiboGreen assay allows detection of as little as 1.0 ng/ml RNA in a standard fluorometer, filter fluorometer, or fluorescence microplate reader-surpassing the sensitivity achieved with ethidium bromide by 200-fold. The linear quantitation range for RiboGreen reagent extends over three orders of magnitude in RNA concentration. Using 750 nM RiboGreen reagent, we quantitated 20 ng/ml to 1.0 microg/ml RNA. By diluting the reagent to 75 nM, we could quantitate 1.0 to 50 ng/ml RNA. Both assay ranges exhibited linear fluorescence increases versus RNA concentration (r2 = 0.999). Assay linearity was maintained in the presence of salts, protein, urea, ethanol, chloroform, agarose, and some detergents. Several different RNA types yielded similar signal intensities and detection sensitivities. The assay is easy to use, rapid, and readily adaptable for automation.


Asunto(s)
Colorantes Fluorescentes/química , Indicadores y Reactivos/química , ARN/análisis , Artefactos , Sensibilidad y Especificidad , Espectrometría de Fluorescencia
16.
Anal Biochem ; 251(2): 144-52, 1997 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-9299009

RESUMEN

We have prepared casein conjugates of two BODIPY dyes for use as fluorogenic protease substrates in homogeneous assays. Both conjugates are labeled to such an extent that the dyes are efficiently quenched in the protein, yielding virtually nonfluorescent substrate molecules. These fluorogenic substrates release highly fluorescent BODIPY dye-labeled peptides upon protease digestion, with fluorescence increases proportional to enzyme activity. These quenched substrates are suitable for the continuous assay of enzymatic activity using standard fluorometers, filter fluorometers, or fluorescence microplate readers using either fluorescein excitation and emission wavelengths to measure BODIPY FL casein hydrolysis or Texas Red wavelengths to detect proteolysis of BODIPY TR-X casein. Most current techniques for detecting protease activity, such as the fluorescein thiocarbamoyl casein (FTC-casein) protease assay, require extensive manipulation, including separation steps, and are therefore labor intensive and error-prone. In comparison, we found the BODIPY dye-labeled casein protease assays to be simple and precise and to have greater sensitivity and a broader dynamic range of detection than the FTC-casein assay. We were able to sensitively detect the activities of a wide variety of enzymes with these new substrates, including serine, acid, sulfhydryl, and metalloproteases. We also found the assay suitable for quantitating protease inhibitor concentrations and for real-time analysis of proteolysis.


Asunto(s)
Compuestos de Boro , Caseínas/química , Endopeptidasas/análisis , Colorantes Fluorescentes , Inhibidores de Proteasas/análisis , Animales , Fluoresceína-5-Isotiocianato , Técnica del Anticuerpo Fluorescente Directa , Humanos , Hidrólisis , Espectrometría de Fluorescencia , Xantenos
17.
Anal Biochem ; 249(2): 228-38, 1997 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-9212875

RESUMEN

A sensitive assay for detecting double-stranded (ds) DNA in solution is described. This assay employs a new dye, PicoGreen dsDNA quantitation reagent, which becomes intensely fluorescent upon binding nucleic acids. The brightness of this reagent is due to its high quantum yield (approximately 0.5, bound to ds calf thymus DNA) and large molar extinction coefficient (approximately 70,000 cm-1 M-1). The fluorescence enhancement of this dye upon binding dsDNA is > 1000-fold, with excitation and emission maxima near those of fluorescein. Unlike Hoechst 33258, PicoGreen reagent fluorescence intensity was the same upon binding to poly(dA).poly(dT) and poly(dG).poly(dC) homopolymers. The PicoGreen assay allowed the detection of 25 pg/ml dsDNA, surpassing the sensitivity achieved with Hoechst 33258 by 400-fold. The linear concentration range for DNA quantitation extended over four orders of magnitude-25 pg/ml to 1 microgram/ml-with a single dye concentration. Assay linearity was maintained even in the presence of salts, proteins, poly(ethylene glycol), urea, chloroform, ethanol, and agarose; some ionic detergents and heparin interfered. Linear DNAs yielded slightly brighter signals than supercoiled plasmids. Finally, the assay showed greater dsDNA:RNA selectivity than Hoechst 33258 in low ionic strength buffer and better dsDNA:single-stranded DNA selectivity in 1 M NaCl.


Asunto(s)
ADN/análisis , Colorantes Fluorescentes/química , Animales , Sitios de Unión , Bovinos , ADN/metabolismo , ADN de Cadena Simple/metabolismo , Estabilidad de Medicamentos , Colorantes Fluorescentes/metabolismo , Fluorometría , Indicadores y Reactivos , Luz/efectos adversos , Compuestos Orgánicos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Soluciones
18.
J Histochem Cytochem ; 44(12): 1363-72, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8985128

RESUMEN

Investigation of mitochondrial morphology and function has been hampered because photostable, mitochondrion-specific stains that are retained in fixed, permeabilized cells have not been available. We found that in live cell preparations, the CMXRos and H2-CMXRos dyes were more photostable than rhodamine 123. In addition, fluorescence and morphology of mitochondria stained with the CMXRos and CMXRos-H2 dyes were preserved even after formaldehyde fixation and acetone permeabilization. Using epifluorescence microscopy, we showed that CMXRos and H2-CMXRos dye fluorescence fully co-localized with antibodies to subunit I of cytochrome c oxidase, indicating that the dyes specifically stain mitochondria. Confocal microscopy of these mitochondria yielded colored banding patterns, suggesting that these dyes and the mitochondrial enzyme localize to different suborganellar regions. Therefore, these stains provide powerful tools for detailed analysis of mitochondrial fine structure. We also used poisons that decrease mitochondrial membrane potential and an inhibitor of respiration complex II to show by flow cytometry that the fluorescence intensity of CMXRos and H2-CMXRos dye staining responds to changes in mitochondrial membrane potential and function. Hence, CMXRos has the potential to monitor changes in mitochondrial function. In addition, CMXRos staining was used in conjunction with spectrally distinct fluorescent probes for the cell nucleus and the microtubule network to concomitantly evaluate multiple features of cell morphology.


Asunto(s)
Colorantes Fluorescentes , Mitocondrias , Rodaminas , Células 3T3 , Animales , Bovinos , Membranas Intracelulares/metabolismo , Ratones , Microscopía Confocal , Mitocondrias/metabolismo , Permeabilidad , Rodamina 123
19.
Anal Biochem ; 239(2): 223-37, 1996 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-8811914

RESUMEN

We have developed two new fluorescent dyes, SYPRO Orange protein gel stain and SYPRO Red protein gel stain, to detect proteins in electrophoretic gels. Stained protein bands can be excited by ultraviolet light at approximately 300 nm, or at visible wavelengths, with excitation maxima of 472 nm for the Orange stain and 547 nm for the Red stain. Detection can be documented with sensitivity similar to that achieved with silver stain, using standard UV transilluminators and Polaroid 667 black and white film, CCD cameras, or commercially available laser scanners. Staining with these dyes is noncovalent and is accomplished using a one-step procedure. Protein gels do not require fixation steps prior to incubation with the dyes. Staining is complete 30 to 60 min following electrophoresis, with no destaining required. Staining can also be accomplished by including dye in the running buffer; in this case a brief one-step destaining procedure follows electrophoresis. The dyes appear to bind to the detergent coat surrounding proteins in sodium dodecyl sulfate (SDS) denaturing gels; thus, staining in such gels is not strongly selective for particular polypeptides. Fluorescent signals are relatively photostable, allowing multiple photographs of gels to be taken without significant signal reduction.


Asunto(s)
Electroforesis en Gel de Poliacrilamida/métodos , Colorantes Fluorescentes , Fluorometría/métodos , Proteínas/análisis , Animales , Bovinos , Pollos , Complejo IV de Transporte de Electrones/análisis , Electroforesis en Gel Bidimensional , Rayos Láser , Peso Molecular , Conejos , Tinción con Nitrato de Plata
20.
Clin Podiatr Med Surg ; 11(2): 301-9, 1994 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8205516

RESUMEN

A new technique to establish the functional subtalar joint axis in live models is presented. Previous studies had a poor reference to the body planes because they relied on cadaver bone models and were not referenced to actual live function. The lower value for the function axis is due to the response of the midtarsal joint and forefoot to loading and ground reactive forces. The techniques were applied to the clinical setting by establishing a reference line on lateral RCSP radiographs and calculating the actual axis to this reference line. The axis deviated from the reference line by a small range (4 degrees) and can be corrected by reference to the calcaneal inclination angle for high or low angular differences. This simple technique can be used clinically to determine axial changes that may be required for surgical procedures and for evaluating the effect of orthosis control.


Asunto(s)
Articulación Talocalcánea/fisiología , Adolescente , Adulto , Fenómenos Biomecánicos , Humanos , Persona de Mediana Edad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA