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1.
Eur J Radiol ; 142: 109859, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34284232

RESUMEN

Portal vein thrombosis is a pathological condition characterized by the lumen occlusion of the portal vein and its intrahepatic branches, commonly associated to chronic liver diseases. Portal vein thrombosis is often asymptomatic and discovered as an incidental finding in the follow-up of chronic hepatopathy. Imaging plays a pivotal role in the detection and characterization of portal vein thrombosis in patients with hepatocellular carcinoma. Ultrasound and Color-Doppler ultrasound are usually the first-line imaging modalities for its detection, but they have limits related to operator-experience, patient size, meteorism and the restrained field-of view. Unenhanced cross-sectional imaging doesn't provide specific signs of portal vein thrombosis except under certain specific circumstances. Conventional contrast-enhanced imaging can depict portal vein thrombosis as an endoluminal filling defect best detected in venous phase and can differentiate between non-neoplastic and neoplastic thrombus based on the contrast enhanced uptake, but not always rule-out the malignant nature. Functional and quantitative imaging techniques and software seem to be more accurate. The purpose of this work is to provide the reader with an accurate overview focused on the main imaging features of portal vein thrombosis.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Trombosis , Trombosis de la Vena , Carcinoma Hepatocelular/complicaciones , Carcinoma Hepatocelular/diagnóstico por imagen , Humanos , Neoplasias Hepáticas/complicaciones , Neoplasias Hepáticas/diagnóstico por imagen , Vena Porta/diagnóstico por imagen , Trombosis de la Vena/diagnóstico por imagen
2.
Eur Rev Med Pharmacol Sci ; 24(7): 3849-3875, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32329861

RESUMEN

The increasing incidence of chronic pathologies and especially non-AIDS defining cancers, such as lung cancer, hepatocellular carcinoma, breast cancer, colorectal cancer, prostate cancer, and Hodgkin's lymphoma after the introduction of combined antiretroviral therapy requires the infectious diseases specialist to know how and when to suspect and diagnose cancer in people living with HIV. The aim of this review is to provide updated studies and information about non-AIDS defining cancers and their management in PLWH sheading a light on possible futures scenarios.


Asunto(s)
Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Neoplasias/diagnóstico , Neoplasias/terapia , Humanos , Neoplasias/complicaciones
3.
Radiologe ; 56(7): 612-21, 2016 Jul.
Artículo en Alemán | MEDLINE | ID: mdl-27364727

RESUMEN

CLINICAL/METHODICAL ISSUE: Magnetic resonance imaging (MRI) of the breast is an indispensable tool in breast imaging for many indications. Several functional parameters with MRI and positron emission tomography (PET) have been assessed for imaging of breast tumors and their combined application is defined as multiparametric imaging. Available data suggest that multiparametric imaging using different functional MRI and PET parameters can provide detailed information about the hallmarks of cancer and may provide additional specificity. STANDARD RADIOLOGICAL METHODS: Multiparametric and molecular imaging of the breast comprises established MRI parameters, such as dynamic contrast-enhanced MRI, diffusion-weighted imaging (DWI), MR proton spectroscopy ((1)H-MRSI) as well as combinations of radiological and MRI techniques (e. g. PET/CT and PET/MRI) using radiotracers, such as fluorodeoxyglucose (FDG). METHODICAL INNOVATIONS: Multiparametric and molecular imaging of the breast can be performed at different field-strengths (range 1.5-7 T). Emerging parameters comprise novel promising techniques, such as sodium imaging ((23)Na MRI), phosphorus spectroscopy ((31)P-MRSI), chemical exchange saturation transfer (CEST) imaging, blood oxygen level-dependent (BOLD) and hyperpolarized MRI as well as various specific radiotracers. ACHIEVEMENTS: Multiparametric and molecular imaging has multiple applications in breast imaging. Multiparametric and molecular imaging of the breast is an evolving field that will enable improved detection, characterization, staging and monitoring for personalized medicine in breast cancer.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/metabolismo , Imagen por Resonancia Magnética/métodos , Imagen Molecular/métodos , Imagen Multimodal/métodos , Tomografía de Emisión de Positrones/métodos , Radiofármacos/farmacocinética , Biomarcadores/metabolismo , Diagnóstico Diferencial , Femenino , Humanos , Masculino
4.
Neurocase ; 20(2): 225-9, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23548099

RESUMEN

Our objective was to assess the role of Intrathecal Baclofen Therapy (ITB) in the cortical reorganization in a patient affected by multiple sclerosis (MS) undergoing physical therapy. We reported a case of a woman affected by MS and severe spasticity, who performed an fMRI examination, before and after the ITB implantation. The subject showed controlateral motor cortex activation after motor task. After a month of ITB implantation, patient showed ipsilateral and controlateral motor cortex activation although with a broader extension. fMRI examination supported the hypothesis of a central influence in patients who undergo physiotherapy and therapy with ITB.


Asunto(s)
Baclofeno/uso terapéutico , Encéfalo/efectos de los fármacos , Agonistas de Receptores GABA-B/uso terapéutico , Corteza Motora/efectos de los fármacos , Esclerosis Múltiple/tratamiento farmacológico , Encéfalo/fisiopatología , Mapeo Encefálico , Femenino , Humanos , Inyecciones Espinales , Imagen por Resonancia Magnética , Persona de Mediana Edad , Actividad Motora/efectos de los fármacos , Corteza Motora/fisiopatología
5.
Funct Neurol ; 28(2): 73-82, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24125556

RESUMEN

Magnetic resonance imaging (MRI) provides an in vivo assessment of cortical and subcortical regions affected in Parkinson's disease (PD). This review summarizes the most important conventional and non-conventional MRI techniques applied in this field. Standard neuroimaging techniques have played a marginal role in the diagnosis and follow-up of PD, essentially being used only to discriminate atypical syndromes from PD, to exclude secondary causes such as vascular lesions, and to confirm the absence of specific imaging features found in atypical parkinsonisms. However, non-conventional MRI techniques, i.e. new neuroimaging approaches such as magnetic resonance spectroscopy, diffusion tensor imaging, and functional MRI, may allow the detection of structural, functional and metabolic changes useful not only for differential diagnosis, but also for early diagnosis and outcome and treatment monitoring in PD. In addition, we illustrate the advantages of high-field MRI over lower magnetic fields, highlighting the great potential of advanced neuroimaging techniques.


Asunto(s)
Imagen de Difusión Tensora/métodos , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética/métodos , Enfermedad de Parkinson/diagnóstico , Diagnóstico Precoz , Humanos
6.
Pregnancy Hypertens ; 2(3): 203, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26105262

RESUMEN

INTRODUCTION: Early onset placenta Preeclampsia (ePE) with Intrauterine Growth Restriction (IUGR) is associated with insufficient placental function, leading to decreased nutrient and oxygen (O2) availability for the fetus [1]. Mitochondria (mt) are the cell energy producers. Mt dysfunctions could be involved in altered placental metabolism leading to ePE and IUGR. We previously demonstrated higher levels of mtDNA in human IUGR placentas [2]. OBJECTIVES: Here we investigate mtDNA levels in ePE and PE without IUGR placentas, and we present an innovative technique, High Resolution Respirometry (HRR), on cytotrophoblast cells (CTC) from PE, IUGR and control placentas (C), measuring cell O2 consumption which represents respiratory chain efficiency. METHODS: mtDNA was measured by Real-Time PCR in 20 PE placentas, with (n=14) or without (n=6) IUGR, and 45 C. CTC were isolated from 4 PE, 4 IUGR and 6 C and characterized by flow cytometry, staining samples with anti-cytokeratin-7 and anti-vimentin antibodies. Cells were located in chambers with atmospheric O2levels; 2 different protocols were used, with or without digitonin permeabilization, allowing to measure the O2 consumption of the respiratory chain complexes singularly or all together. Substrates and inhibitors of different respiratory chain complexes were sequentially administered (succinate, ADP, oligomycin, FCCP, rotenone, antimycin A, glutamate, malate, myxothiazol, TMPD, ascorbate, pyruvate, cytochrome C, differently combined depending on the protocol) and O2 consumption levels were recorded. Data were normalized by Citrate Synthase (CS) activity and CTC mtDNA content. RESULTS: PE placentas: mtDNA content was significantly increased in ePE+IUGR (p=0.02) vs C; opposite to this, mtDNA was decreased in PE without IUGR (p=0.03). CTC: single mt O2 consumption (obtained by normalizing data both by CS activity and mtDNA) was slightly increased both in PE and IUGR. The global cell respiration was increased, though not significantly. The trend towards higher O2 consumption studied on permeabilized cells  was confirmed for all the respiratory chain complexes. CONCLUSION: Our study showed that mtDNA is increased also in ePE with IUGR and added the novel observation that mtDNA is decreased in PE without IUGR. In both conditions placental mitochondria present an altered respiratory chain activity, with a trend to a higher respiratory capacity. This could lead to higher ATP production likely as an attempt to compensate for other aspects of placental disease due to small or inefficient exchange capabilities. Further data are needed to confirm these preliminary results, together with specific enzymatic assays to asses the respiratory chain complexes functionality. Supported by Fondazione Giorgio Pardi, Associazione Studio Malformazion(ASM) and by a Grant COFIN (Italian Ministry of Research) on: New markers for preterm deliveries.

7.
Eur Ann Allergy Clin Immunol ; 38(1): 15-9, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16544583

RESUMEN

OBJECTIVE: Chronic Idiopathic Urticaria (CIU), conventionally defined as the occurrence of widespread itchy weals lasting for at least six weeks, has a significant place among the dermatoses related to psychological factors. Emotions that cannot be expressed or elaborated, may be important in the etiology. The objective of this study was to evaluate the characteristics of patients with CIU and compare them in terms of alexithymia. METHODS: Forty consecutive subjects with chronic urticaria were recruited from an outpatient allergologic clinic. All of the subjects completed Toronto Alexithymia Scale, Rorschach Inkblot Test according with Comprehensive System modified by Maurizio Cuffaro administration rules and the Family Drawing Test by Corman. RESULTS: CIU patients had higher alexithymia levels (p < .05) on comparison to the normal population. There was also a positive correlation between CIU patients and the presence of depressant characteristics as evaluated by Rorschach Inkblot Test and Family Drawing Test. DISCUSSION: CIU, a severe and chronic dermatological problem, may be related to affect-regulation, particularly alexithymia. Individuals with CIU might benefit from learning how to regulate their emotions other than by medical treatments.


Asunto(s)
Síntomas Afectivos/complicaciones , Urticaria/complicaciones , Urticaria/psicología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prueba de Rorschach
8.
Medifam (Madr.) ; 12(8): 523-525, ago. 2002.
Artículo en Es | IBECS | ID: ibc-16567

RESUMEN

El ciprofloxacino es una fluoroquinolona con una amplia variedad de indicaciones terapéuticas. Las fluoroquinolonas pueden inducir reacciones adversas neurológicas en aproximadamente un 1 -4 per cent de los pacientes. Se describen dos pacientes con reacciones adversas sobre el sistema nervioso central asociadas a tratamiento con ciprofloxacino oral. Un paciente presentó un cuadro de agitación psicomotriz y otro un cuadro de temblor de reposo, que se resolvieron tras la suspensión del ciprofloxacino (AU)


Asunto(s)
Anciano , Femenino , Masculino , Humanos , Ciprofloxacina/efectos adversos , Sistema Nervioso Central , Antiinfecciosos/efectos adversos , Atención Primaria de Salud
9.
Forensic Sci Int ; 119(1): 87-96, 2001 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-11348798

RESUMEN

Reliable amplification of short tandem repeat (STR) DNA markers with the polymerase chain reaction (PCR) is dependent on high quality PCR primers. The particular primer combinations and concentrations are especially important with multiplex amplification reactions where multiple STR loci are simultaneously copied. Commercially available kits are now widely used for STR amplification and subsequent DNA typing. We present here the use of high performance liquid chromatography (HPLC) and time-of-flight mass spectrometry (TOF-MS) methods for characterization of commercially available STR kits.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Cartilla de ADN/normas , Medicina Legal/métodos , Espectrometría de Masas/métodos , Repeticiones de Minisatélite/genética , Técnicas de Amplificación de Ácido Nucleico/métodos , Reacción en Cadena de la Polimerasa/métodos , Análisis Discriminante , Humanos , Control de Calidad , Factores de Tiempo
12.
Anal Chem ; 73(3): 620-4, 2001 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-11217771

RESUMEN

Currently, a major focus of human genetics is the utilization of single-nucleotide polymorphisms for clinical diagnostics, whole-genome linkage disequilibrium screens to identify common disease genes such as Alzheimer disease, determination of the recent evolutionary history of a species, and the process of speciation. We have examined single-nucleotide extension coupled with high-performance liquid chromatography as a method to simultaneously genotype two SNPs occurring in the coding region of the HFE gene that produce clinical effects. This assay allows concurrent genotyping of the C282Y and H63D mutations in 11 min and is 100% concordant with current testing methods for both of these mutations.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Antígenos HLA/genética , Hemocromatosis/genética , Antígenos de Histocompatibilidad Clase I/genética , Proteínas de la Membrana , Mutación , Secuencia de Bases , Cartilla de ADN , Genotipo , Proteína de la Hemocromatosis , Humanos , Reacción en Cadena de la Polimerasa
13.
Genet Test ; 4(2): 125-9, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10953951

RESUMEN

We describe a novel molecular screening technique for hereditary hemochromatosis through which HFE genotypes at codon positions 282 and 63 are simultaneously detected. The technique combines multiplex PCR and denaturing high-performance liquid chromatography (DHPLC) and allows automated high-throughput analysis. We used this method to genotype 43 previously characterized anonymous DNA specimens in blinded fashion and found multiplex PCR/DHPLC 100% accurate when compared with PCR/restriction enzyme digestion, yet far more efficient.


Asunto(s)
Antígenos HLA/genética , Hemocromatosis/genética , Antígenos de Histocompatibilidad Clase I/genética , Proteínas de la Membrana , Mutación , Secuencia de Bases , Cromatografía Líquida de Alta Presión/métodos , Codón , Cartilla de ADN , Tamización de Portadores Genéticos , Hemocromatosis/diagnóstico , Proteína de la Hemocromatosis , Humanos , Reacción en Cadena de la Polimerasa/métodos
14.
Am J Hum Genet ; 67(2): 432-43, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10873789

RESUMEN

A population study of heteroplasmy in the hypervariable region 1 (HV1) portion of the human mtDNA control region was performed. Blood samples from 253 randomly chosen individuals were examined using a sensitive denaturing gradient-gel electrophoresis (DGGE) system. This method is capable of detecting heteroplasmic proportions as low as 1% and virtually all heteroplasmy where the minor component is > or = 5%. Heteroplasmy was observed in 35 individuals (13.8%; 95% confidence interval [CI] 9.6-18.0). Of these individuals, 33 were heteroplasmic at one nucleotide position, whereas 2 were heteroplasmic at two different positions (a condition known as "triplasmy"). Although heteroplasmy occurred at a total of 16 different positions throughout HV1, it was most frequently observed at positions 16093 (n=13) and 16129 (n=6). In addition, the majority of heteroplasmic variants occurred at low proportions and could not be detected by direct sequencing of PCR products. This study indicates that low-level heteroplasmy in HV1 is relatively common and that it occurs at a broad spectrum of sites. Our results corroborate those of other recent reports indicating that heteroplasmy in the control region is more common than was previously believed-a finding that is of potential importance to evolutionary studies and forensic applications that are based on mtDNA variation.


Asunto(s)
Citoplasma/genética , ADN Mitocondrial/genética , Variación Genética/genética , Ácidos Nucleicos Heterodúplex/genética , Secuencias Reguladoras de Ácidos Nucleicos/genética , Secuencia de Bases , Análisis Mutacional de ADN/métodos , Electroforesis en Gel de Agar , Etnicidad/genética , Evolución Molecular , Humanos , Análisis de los Mínimos Cuadrados , Mitocondrias/genética , Mutación/genética , Desnaturalización de Ácido Nucleico/genética , Filogenia , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad
15.
Anal Chem ; 72(4): 858-64, 2000 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-10701274

RESUMEN

Genotyping based on short tandem repeat (STR) regions is used in human identification and parentage testing, gene mapping studies, cancer diagnostics, and diagnosis of hereditary diseases. Analysis of STR systems using slab gel electrophoresis requires lengthy and labor-intensive procedures. Therefore, alternative methods such as capillary electrophoresis or ion-pair reversed-phase high-performance liquid chromatography (IPRP HPLC) have been used to analyze DNA. IPRP HPLC offers an attractive substitute to gel electrophoresis for STR analysis because of the reduced analysis time, and there is no need for the waste disposal associated with radioisotopic, enzyme-linked, or fluorescence detection systems. We evaluated the use of IPRP HPLC for the sizing and typing of STR alleles from the HUMTHO1 locus. The IPRP HPLC conditions (column temperature, flow rate, percent organic modifier per minute) were optimized for the separation of PCR products. Using the optimized separation conditions, the alleles of the HUMTHO1 system were sized in their native state (double standard) with the use of internal markers. The typing results correlated 100% to accepted methods of DNA typing. The analysis time for the HUMTHO1 locus was less than 14 min, and the alleles could be peak captured for further examination following such as sequencing.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , ADN/genética , Repeticiones de Microsatélite , Alelos , ADN/análisis , ADN/sangre , Marcadores Genéticos/genética , Humanos , Reacción en Cadena de la Polimerasa
16.
J Chromatogr B Biomed Sci Appl ; 732(2): 365-74, 1999 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-10517359

RESUMEN

DNA analysis using capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection requires that polymerase chain reaction products either be prepared using primers with fluorescent molecules covalently bonded to them, or stained with a fluorescent intercalation dye following amplification. The intercalation technique has the advantage of allowing fluorescence detection of any double-stranded DNA (dsDNA) product regardless of the amplification primers used. The increased sensitivity of LIF detection is sometimes compromised by the intercalation dye changing the mass to charge ratio of the DNA. The purpose of this study was to evaluate the changes of migration rate, resolution and fluorescent intensity of dye-DNA complexes during electrophoretic separations, and to establish the optimal parameters for short tandem repeats alleles profiling. The alleles of three STR loci THO1, F13A01 and vWFA31 were intercalated with the monomeric dyes TOPRO-1 and YOPRO-1, and their corresponding dimers, TOTO-1 and YOYO-1 (Molecular Probes, Eugene, OR, USA). Alleles intercalated before injection onto the CE column resulted in loss of resolution and sensitivity when compared to the on-column labeling technique. The results of this experimentation were then applied to a STR typing assay using a commercially available polymer and buffer matrix. This assay included development of a unique internal standard used for migration time normalization assignment of alleles. Consequently, the 9 allele and the 9.3 microvariant of the THOI locus were separated and typed correctly with a resolution of 0.49 in less than 20 min, and the only sample preparation necessary after amplification was a dilution step.


Asunto(s)
Benzoxazoles/análisis , ADN/análisis , Electroforesis Capilar/métodos , Sustancias Intercalantes/análisis , Compuestos de Quinolinio/análisis , Espectrometría de Fluorescencia/métodos , Alelos , Genotipo , Rayos Láser , Estándares de Referencia , Secuencias Repetidas en Tándem/genética
17.
Ground Water ; 37(5): 649-59, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-19125917

RESUMEN

A modeling approach is developed to evaluate the potential for artificial recharge on alluvial fans in the Salinas Valley, California, using limited data of soil texture, soil hydraulic properties, and interwell stratigraphy. Promising areas for surface recharge are identified and mapped on a broad-scale using soil surveys, geologic investigations, permeability tests, and seasonal ground water response to rainfall and runoff. Two-dimensional representations of the vadose zone at selected sites are then constructed from drillers'logs and soil material types are estimated. Next, hydraulic properties are assigned to each soil material type by comparing them to laboratory-tested cores of similar soils taken from one site. Finally, water flow through the vadose zone is modeled in two dimensions at seven sites using a transient, finite-difference, variably saturated flow model. Average infiltration rates range from 0.84 to 1.54 cm/hr and recharge efficiency, the percentage of infiltrated water that reaches the water table, varies from 51% to 79%. Infiltration rates and recharge efficiency are found to be relatively insensitive to recharge basin ponding depth due to the thickness of the vadose zones modeled (31 to 84 m). The impact of artificial recharge on the Salinas Valley ground water basin is investigated by simulating the regional ground water response to surface spreading and streamflow augmentation with a recently calibrated, finite-element, ground water-surface water model for the basin. It was determined that a combined approach of surface recharge and streamflow augmentation significantly reduces the state of ground water overdraft and, to a lesser extent, reduces the rate of sea water intrusion.

18.
Anal Chem ; 70(21): 4514-9, 1998 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-9823710

RESUMEN

Short tandem repeat (STR) alleles are popular for use as forensic markers due to their highly polymorphic nature. Commonly they are separated by gel electrophoresis and visualized using intercalation dyes. The purpose of this study was to determine the changes in absorbance and fluorescence of DNA-intercalation dye complexes as a function of base pair (bp)-to-dye ratio. The DNA samples consisted of STR alleles from loci THO1, F13A01, and vWFA31. The alleles were PCR amplified and HPLC purified to ensure that only the desired DNA fragment was present in each sample. Alleles ranged in size from 151 bp for locus vWFA (allele 17) to 199 bp for the locus F13A01 (allele 8). The adenine and thymine (AT) content varied from 48% for the THO1 locus to 69% for F13A01 and vWFA31 loci. The homozygous alleles of each locus were mixed individually with the bis-intercalators TOTO-1 and YOYO-1 and their corresponding monomeric dyes TOPRO-1 and YOPRO-1. The absorbance of the DNA-dye complex at 260 nm increased with addition of each intercalation dye. Subtraction of the dye absorbance rendered the DNA absorbance constant at 260 nm. Fluorescence emission increased dramatically upon intercalation of both the monomeric and dimeric dyes into the DNA helix. A plateau of fluorescence intensity was observed at base pair-to-dye ratios of 10/1 for the bis-intercalator TOTO-1 and 5/1 for YOYO-1 for all three loci. The greatest fluorescence intensity response was obtained with the intercalator YOYO-1 using allele 8 of the F13A01 locus, which had the greatest AT concentration.


Asunto(s)
Alelos , Colorantes Fluorescentes/química , Sustancias Intercalantes/química , Secuencias Repetidas en Tándem , Adenina/análisis , Emparejamiento Base , Homocigoto , Humanos , Reacción en Cadena de la Polimerasa , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta , Timina/análisis
19.
Electrophoresis ; 19(1): 108-18, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9511871

RESUMEN

Polymerase chain reaction (PCR) amplified alleles need to be isolated and purified before carrying out additional analysis to confirm sequence, number of repeats and microvariants within a short tandem repeat (STR) locus. Also, PCR amplification of tetranucleotide repeat loci, used in DNA typing assays, often result in heteroduplex formation, adding to the complexity of analysis. Sequencing reactions require single specific target DNA for reliable sequencing analysis. Alkylated poly(styrene-divinylbenzene) columns at elevated temperature and gradient elution conditions increase the efficiency of separation to allow for the purification of PCR products. Using the separation technique of ion-pairing reverse-phase (IPRP) high performance liquid chromatography (HPLC), molecular biologists can separate and purify DNA fragments without alteration to the double-stranded DNA sequencing properties. In this study, the IP-RP chromatography technique has been demonstrated by separation of alleles of the short tandem repeat loci of TH01, vWA31, F13A01 and FES/ FPS. Alleles differing in size range of 12 to 4 base pairs were separated by IPRP/HPLC and individual alleles were peak-captured, then cycle-sequenced. These HPLC fractions required no additional steps prior to cycle sequencing. Capillary electrophoresis (CE) was used to sequence the alleles. Furthermore, CE offers advantages over traditional slab methods via automation and higher applied voltages. Interestingly, unlike traditional gel electrophoresis, samples were introduced into the sieving matrix by electrokinetic injection, which allows for multiple injections from a single sample, a key feature for method development. Applied voltage was 320 V per centimeter using a nonderivatized fused silica capillary with an interior diameter of 50 microm and a total length of 47 centimeters. The total analysis time including capillary filling and pre-electrophoresis was less than 30 min for a 220-bp fragment. A sequencing rate of 530 bp/h was achieved using these conditions. By combining the techniques of HPLC separation and CE sequencing, the results confirmed the sequence and number of nucleotide repeats for each STR loci. An average sequencing efficiency of 97% was achieved. Additionally, this method defined the absence of a 9.3 microvariant for a TH01 heterozygous individual previously typed as a 9, 9.3/10 using slab gel electrophoresis. The techniques described can be applied to other DNA purification and isolation problems.


Asunto(s)
Alelos , Cromatografía Líquida de Alta Presión/métodos , Electroforesis Capilar/métodos , Secuencias Repetitivas de Ácidos Nucleicos , Secuencia de Bases , ADN/aislamiento & purificación , Datos de Secuencia Molecular
20.
Electrophoresis ; 17(9): 1499-504, 1996 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8905267

RESUMEN

Polymerase chain reaction (PCR)-based DNA typing is routinely used in forensics for identity testing. Those assays that distinguish single nucleotide polymorphisms (SNPs) require other biochemical reactions in addition to PCR to identify the sequence polymorphisms. Low-stringency sequence-specific PCR (LSSP-PCR) is an example of a recent method that does not require additional biochemical treatments. The analysis of LSSP-PCR by capillary electrophoresis (CE) to discriminate the highly polymorphic mitochondrial DNA (mtDNA) D-loop region is described. The DNA from five individuals were amplified (first step) using sequence-specific primers to produce 1021 bp fragments containing the D-loop region. Each fragment was isolated by electroelution using CE and UV detection, and subjected to a second amplification (second step) using a single primer annealed under low stringency conditions. This generated a range or profile of PCR products for each sample, which were resolved and analyzed by CE with the intercalator TOTO-1 and laser-induced fluorescence (LIF) detection. The LSSP-PCR profiles were unique for each individual, indicating that this technique may be applicable for forensic identity testing.


Asunto(s)
ADN Mitocondrial/genética , Electroforesis Capilar , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Cartilla de ADN , ADN Mitocondrial/química , Electroforesis Capilar/métodos , Colorantes Fluorescentes , Humanos , Sustancias Intercalantes , Rayos Láser , Reacción en Cadena de la Polimerasa/métodos , Tiazoles
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