Biomedical subjects

Hsin-Chih Yeh

Publications and source records attributed to Hsin-Chih Yeh.

6 recordsLinked to original sources

PubMed2006

A microfluidic-FCS platform for investigation on the dissociation of Sp1-DNA complex by doxorubicin.

The transcription factor (TF) Sp1 is a well-known RNA polymerase II transcription activator that binds to GC-rich recognition sites in a number of essential cellular and viral promoters. In addition, direct interference of Sp1 binding to DNA cognate sites using DNA-interacting compounds may provide promising therapies for suppression of cancer progression and viral replication. In this study, we present a rapid, sensitive and cost-effective evaluation of a GC intercalative drug, doxorubicin (DOX), in dissociating the Sp1-DNA complex using fluorescence correlation spectroscopy (FCS) in a microfluidic system. FCS allows assay miniaturization without compromising sensitivity, making it an ideal analytical method for integration of binding assays into high-throughput, microfluidic platforms. A polydimethylsiloxane (PDMS)-based microfluidic chip with a mixing network is used to achieve specific drug concentrations for drug titration experiments. Using FCS measurements, the IC50 of DOX on the dissociation of Sp1-DNA complex is estimated to be 0.55 microM, which is comparable to that measured by the electrophoretic mobility shift assay (EMSA). However, completion of one drug titration experiment on the proposed microfluidic-FCS platform is accomplished using only picograms of protein and DNA samples and less than 1 h total assay time, demonstrating vast improvements over traditional ensemble techniques.

DNA↗

PubMed2006

Homogeneous point mutation detection by quantum dot-mediated two-color fluorescence coincidence analysis.

This report describes a new genotyping method capable of detecting low-abundant point mutations in a homogeneous, separation-free format. The method is based on integration of oligonucleotide ligation with a semiconductor quantum dot (QD)-mediated two-color fluorescence coincidence detection scheme. Surface-functionalized QDs are used to capture fluorophore-labeled ligation products, forming QD-oligonucleotide nanoassemblies. The presence of such nanoassemblies and thereby the genotype of the sample is determined by detecting the simultaneous emissions of QDs and fluorophores that occurs whenever a single nanoassembly flows through the femtoliter measurement volume of a confocal fluorescence detection system. The ability of this method to detect single events enables analysis of target signals with a multiple-parameter (intensities and count rates of the digitized target signals) approach to enhance assay sensitivity and specificity. We demonstrate that this new method is capable of detecting zeptomoles of targets and achieve an allele discrimination selectivity factor >10(5).

Cell Line, Tumor↗

PubMed2006

Leiomyoma of the epididymis: a case report.

Tumors of the epididymis, both primary and secondary, and whether benign or malignant, are very rare. Adenomatoid tumors and leiomyoma are the most frequently diagnosed benign tumors of the epididymis. In a review of the American and European literature, leiomyoma was the second most common neoplasm of the epididymis, representing 6% of primary epididymal tumors. A case of leiomyoma of the epididymis in a 53-year-old patient is reported. The patient presented with a 4-year history of a painless mass in the left scrotum. There were no bother some symptoms except gradual enlargement of the tumor. On surgical exploration, the mass was found to be smooth and well-demarcated. A fresh frozen section showed a benign lesion, and conservative excision of the tumor was performed without any difficulty. The leiomyoma was definitively diagnosed by subsequent histopathologic analysis. The details of this rare case are reported herein with a review of the medical literature.

Epididymis↗

PubMed2005

Spontaneous perirenal hematoma: a case report.

Spontaneous perirenal hematoma is relatively uncommon but may be life threatening. There are some challenges in early diagnosis due to the lack of specific presentations. We report a case of spontaneous perirenal hematoma in a patient who had histories of systemic lupus erythematosus, hypertension, and uremia with hemodialysis, and initially presented with non-specific flank pain. Dizziness and unstable vital signs were noted in the emergency room. Computed tomography and abdominal ultrasonography revealed a large perirenal hematoma over the left retroperitoneal cavity. The patient received conservative treatment without surgical intervention and had an uneventful recovery.

Adult↗

PubMed2005

Single-quantum-dot-based DNA nanosensor.

Rapid and highly sensitive detection of DNA is critical in diagnosing genetic diseases. Conventional approaches often rely on cumbersome, semi-quantitative amplification of target DNA to improve detection sensitivity. In addition, most DNA detection systems (microarrays, for example), regardless of their need for target amplification, require separation of unhybridized DNA strands from hybridized stands immobilized on a solid substrate, and are thereby complicated by solution-surface binding kinetics. Here, we report an ultrasensitive nanosensor based on fluorescence resonance energy transfer (FRET) capable of detecting low concentrations of DNA in a separation-free format. This system uses quantum dots (QDs) linked to DNA probes to capture DNA targets. The target strand binds to a dye-labelled reporter strand thus forming a FRET donor-acceptor ensemble. The QD also functions as a concentrator that amplifies the target signal by confining several targets in a nanoscale domain. Unbound nanosensors produce near-zero background fluorescence, but on binding to even a small amount of target DNA (approximately 50 copies or less) they generate a very distinct FRET signal. A nanosensor-based oligonucleotide ligation assay has been demonstrated to successfully detect a point mutation typical of some ovarian tumours in clinical samples.

Animals↗

PubMed2005

Single-molecule detection and probe strategies for rapid and ultrasensitive genomic detection.

This paper reviews the current state-of-the-art development of single-molecule detection (SMD)-based methods for ultrasensitive and specific analysis of genomic sequences. We first discuss several newly devised single fluorescent probe strategies that allow separation-free detection of low-abundance DNA sequences, such as quantum dot (QD)-mediated fluorescence resonance energy transfer (FRET) technology and dual-color fluorescence coincidence and colocalization analysis. Various schemes toward single DNA sizing and sequencing in solutions or on surfaces are also reviewed. In the end, we summarize the different microfluidic approaches developed for use with SMD to facilitate rapid, low-volume and quantitative analysis, such as electrokinetic and hydrodynamic single-molecule manipulation techniques.

DNA Probes↗