Pedicle screw implantation in the thoracic and lumbar spine of 1-4-year-old children: evaluating the safety and accuracy by a computer tomography follow-up.

Study Design: This was a retrospective clinical study.

Objective: To evaluate the safety and accuracy of pedicle screw placement in very young children and to observe its influence on vertebral and spinal canal growth.

Summary Of Background Data: Although widely used, it is not known if pedicle screw fixation is safe and effective in very young children.

Gene delivery by microfluidic flow-through electroporation based on constant DC and AC field.

Electroporation is one of the most widely used physical methods to deliver exogenous nucleic acids into cells with high efficiency and low toxicity. Conventional electroporation systems typically require expensive pulse generators to provide short electrical pulses at high voltage. In this work, we demonstrate a flow-through electroporation method for continuous transfection of cells based on disposable chips, a syringe pump, and a low-cost power supply that provides a constant voltage.

Droplet sorting based on the number of encapsulated particles using a solenoid valve.

Droplet microfluidics provides a high-throughput platform for screening subjects and conditions involved in biology. Droplets with encapsulated beads and cells have been increasingly used for studying molecular and cellular biology. Droplet sorting is needed to isolate and analyze the subject of interest during such screening.

Genomic DNA extraction from cells by electroporation on an integrated microfluidic platform.

The vast majority of genetic analysis of cells involves chemical lysis for release of DNA molecules. However, chemical reagents required in the lysis interfere with downstream molecular biology and often require removal after the step. Electrical lysis based on irreversible electroporation is a promising technique to prepare samples for genetic analysis due to its purely physical nature, fast speed, and simple operation.

Characterizing osmotic lysis kinetics under microfluidic hydrodynamic focusing for erythrocyte fragility studies.

The biomechanics of erythrocytes, determined by the membrane integrity and cytoskeletal structure, provides critical information on diseases such as diabetes mellitus, myocardial infarction, hypertension, and sickle cell anemia. Here we demonstrate a simple microfluidic tool for examining erythrocyte fragility based on characterizing osmotic lysis kinetics. Hydrodynamic focusing is used for generating rapid dilution of the buffer and producing lysis of erythrocytes during their flow.

Simultaneous analysis of 11 main active components in Cirsium setosum based on HPLC-ESI-MS/MS and combined with statistical methods.

A novel method based on high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry was developed for simultaneous determination of the 11 major active components including ten flavonoids and one phenolic acid in Cirsium setosum. Separation was performed on a reversed-phase C(18) column with gradient elution of methanol and 0.1‰ acetic acid (v/v).

Determination of cnidilin and its two metabolites in rat bile and stool after oral administration by HPLC/electrospray ionization tandem mass spectrometry.

A simple, fast and sensitive method for the simultaneous determination of cnidilin and its two metabolites (M1 and M2) in rat bile and stool using HPLC coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) has been developed. The sample pretreatment was simple, because methanol was the only additive used for dilution of bile and ultrasound of stool. Pimpinellin was used as internal standard (IS).

Release of intracellular proteins by electroporation with preserved cell viability.

Extraction of intracellular proteins from cells is often an important first step for conducting molecular biology and proteomics studies. Although ultrasensitive detection and analytical technology at the single molecule level is becoming routine, protein extraction techniques have not followed suit and still call for complete lysis that leads to cell death. In principle, with refined extraction techniques, intracellular proteins can potentially be extracted without killing the cell.

High-resolution manometry correlates of ineffective esophageal motility.

Objectives: There are currently no criteria for ineffective esophageal motility (IEM) and ineffective swallow (IES) in esophageal pressure topography (EPT). Our aims were to use high-resolution manometry metrics to define IEM within the Chicago Classification and to determine the distal contractile integral (DCI) threshold for IES.

Methods: The EPT of 150 patients with either dysphagia or reflux symptoms were reviewed.

Modification of the siRNA passenger strand by 5-nitroindole dramatically reduces its off-target effects.

During the formation of RNA-induced silencing complex (RISC), the passenger and guide strand of an siRNA duplex separate from each other to generate an active RISC complex. Accumulating evidence shows that an siRNA passenger strand can also assemble into a RISC complex and mediate RNA interference, thereby causing undesired off-target effects. To reduce this effect, the so-called "universal base" 5-nitroindole nucleotides were incorporated into an siRNA passenger strand.

Simultaneous determination and pharmacokinetic study of six flavonoids from Fructus Sophorae extract in rat plasma by LC-MS/MS.

In this study, a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of six flavonoids including sophoricoside, genistin, genistein, rutin, quercetin and kaempferol in rat plasma after oral administration of Fructus Sophorae extract using sulfamethalazole as internal standard (IS). The plasma samples were pretreated and extracted by liquid-liquid extraction. Chromatographic separation was accomplished on a C(18) column with a simple linear gradient elution.

Simultaneous determination of nine components in Anemarrhena asphodeloides by liquid chromatography-tandem mass spectrometry combined with chemometric techniques.

A novel quantitative method using high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry was developed for simultaneous determination of the important active constituents including four steroidal saponins, two xanthone glycosides, two isoflavonoids, and one anthraquinone in different parts of Anemarrhena asphodeloides from different habitats. Hierarchical clustering analysis and principal components analysis were performed to differentiate and classify the samples. The separation was performed on a C(18) column with acidified aqueous acetonitrile gradients.

Kinetic magnetic resonance imaging analysis of lumbar segmental mobility in patients without significant spondylosis.

Purpose: The purpose of this study was to examine lumbar segmental mobility using kinetic magnetic resonance imaging (MRI) in patients with minimal lumbar spondylosis.

Methods: Mid-sagittal images of patients who underwent weight-bearing, multi-position kinetic MRI for symptomatic low back pain or radiculopathy were reviewed. Only patients with a Pfirrmann grade of I or II, indicating minimal disc disease, in all lumbar discs from L1-2 to L5-S1 were included for further analysis.

Low-frequency ac electroporation shows strong frequency dependence and yields comparable transfection results to dc electroporation.

Conventional electroporation has been conducted by employing short direct current (dc) pulses for delivery of macromolecules such as DNA into cells. The use of alternating current (ac) field for electroporation has mostly been explored in the frequency range of 10kHz-1MHz. Based on Schwan equation, it was thought that with low ac frequencies (10Hz-10kHz), the transmembrane potential does not vary with the frequency.

Quantum dot (QD)-modified carbon tape electrodes for reproducible electrochemiluminescence (ECL) emission on a paper-based platform.

Stable and sensitive electrochemiluminescence (ECL) detection relies on successful immobilization of quantum dots (QDs) on working electrodes. Herein, we report a new technique to apply double-sided carbon adhesive tape as the working electrode to improve the stability and reproducibility of QD-based ECL emission. CdS QD-modified electrodes were prepared by dropping and drying CdS QD suspension on the carbon adhesive tape supported by indium tin oxide (ITO) glass.

Quantitative measurement of quantum dot uptake at the cell population level using microfluidic evanescent-wave-based flow cytometry.

The intracellular uptake of nanoparticles (NPs) is an important process for molecular and cellular labeling, drug/gene delivery and medical imaging. The vast majority of investigations into NP uptake have been conducted using confocal imaging that is limited to observation of a small number of cells. Such data may not yield quantitative information about the cell population due to the tiny sample size and the potential heterogeneity.

Observing single cell NF-κB dynamics under stimulant concentration gradient.

Study of cell signaling often requires examination of the cellular dynamics under variation in the stimulant concentration. Such variation has typically been conducted by dispensing cell populations in a number of chambers or wells containing discrete concentrations. Such practice adds to the complexity associated with experimental or device design and requires substantial labor for implementation.

Single-stage posterior instrumentation and anterior debridement for active tuberculosis of the thoracic and lumbar spine with kyphotic deformity.

Objective: The purpose of this study was to validate the efficacy and safety of single-stage posterior instrumentation and anterior debridement for treatment of active spinal tuberculosis with kyphotic deformity.

Method: From January 2005 to January 2009, 13 males and 24 females were enrolled in this retrospective study. All patients underwent single-stage posterior instrumentation and fusion, combined with anterior radical debridement and bone grafting.

Chemical transfection of cells in picoliter aqueous droplets in fluorocarbon oil.

The manipulation of cells inside water-in-oil droplets is essential for high-throughput screening of cell-based assays using droplet microfluidics. Cell transfection inside droplets is a critical step involved in functional genomics studies that examine in situ functions of genes using the droplet platform. Conventional water-in-hydrocarbon oil droplets are not compatible with chemical transfection due to its damage to cell viability and extraction of organic transfection reagents from the aqueous phase.

[Surgical management of vertebral sarcoidosis].

Objective: To investigate the clinical characteristics, diagnostic foundation and treatment of vertebral sarcoidosis.

Methods: The clinical data of 13 patients with vertebral sarcoidosis who received anterior debridement and instrumentation were retrospectively analyzed.

Results: The onset of progressive pain in the pathological region was common in the 13 patients.

Transfection of cells using flow-through electroporation based on constant voltage.

Electroporation is a high-efficiency and low-toxicity physical gene transfer method. Classical electroporation protocols are limited by the small volume of cell samples processed (less than 10(7) cells per reaction) and low DNA uptake due to partial permeabilization of the cell membrane. Here we describe a flow-through electroporation protocol for continuous transfection of cells, using disposable devices, a syringe pump and a low-cost power supply that provides a constant voltage.

Single-cell electrical lysis of erythrocytes detects deficiencies in the cytoskeletal protein network.

The network of erythrocyte cytoskeletal proteins significantly influences erythrocyte physical and biological properties. Here we show that the kinetics of erythrocyte lysis during exposure to an electric field is sensitively correlated with defects in the cytoskeletal network. Histograms compiled from single-cell electrical lysis data show characteristics of erythrocyte populations that are deficient in a specific cytoskeletal protein, revealing the presence of cell subpopulations.

Histone modification analysis by chromatin immunoprecipitation from a low number of cells on a microfluidic platform.

Histone modifications are important epigenetic mechanisms involved in eukaryotic gene regulation. Chromatin immunoprecipitation (ChIP) assay serves as the primary technique to characterize the genomic locations associated with histone modifications. However, traditional tube-based ChIP assays rely on large numbers of cells as well as laborious and time-consuming procedures.

Catalytic asymmetric conjugate allylation of coumarins.

A catalytic asymmetric conjugate allylation was successfully developed to synthesize potential pharmacologically active 4-allyl-2-oxochroman skeletons. A dual activation strategy was employed by using N,N'-dioxide-Yb(OTf)(3) to activate coumarins and using (CuOTf)(2)•C(7)H(8) to activate tetraallyltin via transmetalation, respectively. Good yields and enantioselectivities were obtained under mild conditions.

Surgical treatment of cervical kyphosis.

Cervical kyphosis is an uncommon but potentially debilitating and challenging condition. We reviewed the etiology, presentation, clinical and radiological evaluation, and treatment of cervical kyphosis. Based on the current controversy as to the ideal mode of surgical management, we paid particular attention to the available surgical strategies.