Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ChIP”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed2006

Functionalized magnetic micro- and nanoparticles: optimization and application to micro-chip tryptic digestion.

The preparation of an easily replaceable protease microreactor for micro-chip application is described. Magnetic particles coated with poly(N-isopropylacrylamide), polystyrene, poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate), poly(glycidyl methacrylate), [(2-amino-ethyl)hydroxymethylen]biphosphonic acid, or alginic acid with immobilized trypsin were utilized for heterogeneous digestion. The properties were optimized, with the constraint of allowing immobilization in a microchannel by a magnetic field gradient. To obtain the highest digestion efficiency, sub-micrometer spheres were organized by an inhomogeneous external magnetic field perpendicularly to the direction of the channel. Kinetic parameters of the enzyme reactor immobilized in micro-chip capillary (micro-chip immobilized magnetic enzyme reactor (IMER)) were determined. The capability of the proteolytic reactor was demonstrated by five model (glyco)proteins ranging in molecular mass from 4.3 to 150 kDa. Digestion efficiency of proteins in various conformations was investigated using SDS-PAGE, HPCE, RP-HPLC, and MS. The compatibility of the micro-chip IMER system with total and limited proteolysis of high-molecular-weight (glyco)proteins was confirmed. It opens the route to automated, high-throughput proteomic micro-chip devices.

Amyloid beta-Peptides↗
PubMed2006

Do-it-yourself microelectrophoresis chips with integrated sample recovery.

We present a microelectrophoresis chip that is simple to fabricate using the microfluidic tectonics (microFT) platform (Beebe, D. J. et al., Proc. Natl. Acad. Sci. USA 2000, 97, 13488-13493; Agarwal, A. K. et al.,. J. Micromech. Microeng. 2006, 16, 332-340). The device contains a removable capillary insert (RCI) for easy sample collection after separation (Atencia, J. et al.,. Lab Chip 2006, DOI: 10. 1039/b514068d). Device construction is accomplished in less than 20 min without specialized equipment traditionally associated with microelectrophoresis chip construction. microFT was used to build a PAGE device utilizing two orthogonal microchannels. One channel performs standard separations, while the second channel serves as an access point to remove bands of interest from the chip via the RCI. The RCI contains an integrated electrode that facilitates the removal of bands using electrokinetic techniques. The device was characterized using prestained proteins (Pierce BlueRanger and TriChromRanger). Samples were loaded into the microelectrophoresis device via a standard micropipette. An electrical field of 40 V/cm was used to separate and collect the proteins. The microPAGE device is simple to fabricate, benefits from microscale analysis, and includes an on-chip collection scheme that interfaces the macroworld with the microworld.

Electrophoresis, Microchip↗
PubMed2003

Multiorgan transplantation with a new organ-chip technique in mice: preliminary histological data.

A simple model was developed for multiorgan liver-kidney-spleen-intestine transplantation on 108 inbred mice. Donor operations included hepatectomy, nephrectomy, splenectomy, and jejunum segment resection. Following removal of the organ, small slices or abdominal organ "chips" were prepared. During multiorgan recipient operations, chips from each of these organs were transplanted into the omentum; in the control single-organ groups, only 1 organ was transplanted. All animals survived. Biopsies were taken for histology after 6 weeks. All organs were found to have developed a blood supply. In the liver chips, hypertrophied cells could be detected. In the margin of the kidney tissue, both the glomeruli and tubules were preserved. Lymphoid zone and red pulp were intact in spleen chips. All layers of the intestinal chips were identifiable and contained intraluminal mucinous substances. This model is a simple surgical intervention with the possibility of the investigation of 4 organs.

Animals↗
PubMed1983

Pharmacokinetics of cis-dichloro-trans-dihydroxy-bis-isopropylamine platinum IV (CHIP) in patients with advanced cancer.

The pharmacokinetics of a second-generation platinum (Pt) analog cis-dichloro-trans-dihydroxy-bis-isopropylamine platinum IV (CHIP) have been studied in 12 patients at doses from 20 to 350 mg/m2. Three Pt species have been measured: total Pt and non-protein-bound Pt by atomic absorption spectrophotometry, and unchanged CHIP by separation on high-performance liquid chromatography followed by atomic absorption spectrophotometry. Plasma decay of total Pt was biexponential at all doses with a beta-phase half-life of 32.1-124 h. Plasma decay of filterable Pt was monoexponential at low doses but biexponential at high doses, with a terminal-phase half-life of 17.8-54.6 h. Plasma decay of unchanged CHIP was monoexponential at all doses, with a half-life of 0.64-1.27 h. Excretion of Pt after CHIP was rapid up to 10 h after the end of infusion and then slow. The total recovery of Pt was 15%-61% of the dose at 24 h in 19 patients. The data indicated that essentially all plasma Pt after 12 h is in the form of metabolites, most of which are protein-bound. The most striking difference between CHIP and reported data for cisplatin is the biexponential decay of non-protein-bound Pt.

Antineoplastic Agents↗
PubMed1993

Glycaemic effect and satiating capacity of potato chips and milk chocolate bar as snacks in teenagers with diabetes.

In 14 adolescents with diabetes, the postprandial blood glucose, after ingestion of two popular snacks, milk chocolate bar and potato chips, was compared to a prescribed mid-afternoon snack that was isocaloric with the comparison snacks. The prescribed diabetes snack consisted of wholemeal wheat bread, margarine, cheese and apple (1533 kJ/365 kcal): 14% protein, 32% fat and 54% carbohydrate. The milk chocolate bar and the potato chips contained 4% protein, 55% fat and 41% carbohydrate. The mean blood glucose peak was 4.7 (+/- 0.8) mmol/l after the regular diabetes snack, after the milk chocolate bar 2.9 (+/- 0.6) mmol/l, and 3.2 (+/- 0.6) mmol/l after the potato chips (P > 0.05). The mean incremental area under the blood glucose curve was 450.3 (+/- 105.5) mmol/l x 180 min for the regular diabetes snack, 269.5 (+/- 96.7) mmol/l x 180 min for the milk chocolate bar and 191.7 (+/- 95.0) mmol/l x 180 min for the potato chips (P > 0.05). We conclude that an occasional exchange of a regular diabetes afternoon snack for an isocaloric amount of milk chocolate bar or potato chips has no negative impact on the postprandial blood glucose.

Adolescent↗
PubMed2005

Chip devices for miniaturized biotechnology.

Chip devices were introduced in chemistry and molecular biology to improve the read-out of information from molecular systems by efficient analytical procedures and to organize automated experiments. Biochips and chip reactor systems are of interest for cellular processes, too, and can be regarded as components in interfaces for the information exchange between living nature and digital electronic systems. In this minireview, different types of chip reactors for biotechnological applications like nanotiterplates, chip thermocyclers and devices for segmented flow operations are discussed. Finally, an outlook is given on the application of chip reactor systems, which are promising tools for automated experiments with highly parallelized screening procedures, for artificial microcompartmentation, cell analogue systems, micro-ecological studies, investigations on modulated morphogenesis, and for a bioanalogue molecular nanotechnology.

Animals↗
PubMed2001

Interfacing a silicon chip to pairs of snail neurons connected by electrical synapses.

Future hybrid neuron-semiconductor chips will consist of complex neural networks that are directly interfaced to electronic integrated circuits. They will help us to understand the dynamics of neuronal networks and may lead to novel computational facilities. Here we report on an elementary step towards such neurochips. We designed and fabricated a silicon chip for multiple two-way interfacing, and cultured on it pairs of neurons from the pedal ganglia of the snail Lymnaea stagnalis. These neurons were joined to each other by an electrical synapse, and to the chip by a capacitive stimulator and a recording transistor. We obtained a set of neuroelectronic units with sequential and parallel signal transmission through the neuron-silicon interface and the synapse, with a bidirectionally interfaced neuron-pair and with a signal path from the chip through a synaptically connected neuron pair back to the chip. The prospects for assembling more involved hybrid networks on the basis of these neuroelectronic units are considered.

Animals↗
PubMed2005

Cross-talk problem on a fluorescence multi-channel microfluidic chip system.

Development of a compact fluorescence-based detection system for use in a micro-analytical system, such as a point-of-care diagnostic system, often requires a multi-channel microfluidic chip system. Since the materials used for microfluidic chips usually are transparent in the visible region and have a refractive indices higher than that of air or the surrounding environment, the fluorescence emission and scattered excitation light can propagate through the chip. We observed that such propagation can cause cross-talk between adjacent channels, and may become the major source of noise in the system and/or photo bleach the fluorescent samples in the adjacent channels, particularly for the small distances between the channels found in microfluidic chips, usually in order of several micro m. We monitored this cross-talk using fluorescein as a fluorescent sample and Mylar sheeting as a microfluidic chip material. We then discuss how this cross-talk can be avoided using a simple, inexpensive and effective method.

Artifacts↗
PubMed2005

Micro flow-through PCR in a PMMA chip fabricated by KrF excimer laser.

As the third PCR technology, micro flow-through PCR chip can amplify DNA specifically in an exponential fashion in vitro. Nowadays many academies in the world have successfully amplified DNA using their own-made flow-through PCR chip. In this paper, the ablation principle of PMMA at 248 nm excimer laser was studied, then a PMMA based flow-through PCR chip with 20 cycles was fabricated by excimer laser at 19 kv and 18 mm/min. The chip was bonded together with another cover chip at 105( composite function)C, 160 N and 20 minutes. In the end, it was integrated with electrical thermal thin films and Pt 100 temperature sensors. The temperature controllers was built standard PID digital temperature controller, the temperature control precision was +/- 0.2( composite function)C. The temperature grads between the three temperature zones were 16.5 and 22.2( composite function)C respectively, the gaps between the temperature zones could realize heat insulation.

Equipment Design↗
PubMed2007

Manufacturing monodisperse chitosan microparticles containing ampicillin using a microchannel chip.

The purpose of this study was using a developed microfluidic chip to prepare size-controlled monodisperse chitosan microparticles encapsulating ampicillin. Our strategy is that a chitosan aqueous solution (the disperse phase) is fed into the microfluidic chip equipped with a cross-junction microchannel, and is sheared by the viscous oil flows (the continuous phase) to form monodisperse semi-product, chitosan emulsions. These fine emulsions are then gelled into stability upon gelation by injection of copper sulfate solution at the terminal microchannel of the microfluidic chip, and finally the uniform chitosan microparticles are formed in an efficient manner. The proposed chip is fabricated by a CO(2) laser machine on a conventional poly methyl methacrylate (PMMA) substrate. This microfluidic chip has four inlet ports, one cross-channel and one outlet port. We have demonstrated that one can control the size of chitosan microparticles from 100 to 800 microm in diameter (with a variation less than 5%) by altering the relative sheath/sample flow rate ratio. Experimental data showed that when given a steady continuous phase (oil flow), the emulsion size increases with the increase in average velocity of the dispersed phase flow (sample flow). In addition, the release of the model drug (ampicillin) from these microspheres is proved to be once-daily for clinical application. We also revealed that appropriate particle sizes for different release patterns are predictable, enabling better applications of chitosan as a drug carrier.

Ampicillin↗
PubMed1994

Sequence and functional expression of an amphibian water channel, FA-CHIP: a new member of the MIP family.

A new member of the family of water channel proteins (aquaporin-CHIP) related to the major intrinsic protein (MIP) family is described. The cDNA coding for this amphibian CHIP was cloned from frog (Rana esculenta) urinary bladder, a model for the kidney collecting duct, using a RT-PCR cloning strategy. The encoded protein, designated FA-CHIP (frog aquaporin-CHIP), shows 77.4%, 42.4% and 35.6% identity with the three proteins now referred to as the aquaporins of the MIP family, i.e., human CHIP28, WCH-CD and gamma-TIP, respectively. Xenopus leavis injected with FA-CHIP cRNA exhibited a marked increase of the osmotic water permeability.

Amino Acid Sequence↗
PubMed1978

Tissue reactions following apical plugging of the root canal with dentin chips in monkey teeth subjected to pulpectomy.

The tissue reaction following apical plugging of the root canal with dentin chips in monkey teeth subjected to pulpectomy was studied. The reaction was characterized by formation of a cementum-like tissue onto the chips, often walling off the root canal as well as accessory and lateral canals. Twenty-two of twenty-four teeth were rated as successful 95 days after pulpectomy. In the control groups, in which apical plugging of the canal with dentin chips was not attempted, ten of twenty-one teeth were rated as successful at this observation time. In six of the ten successfully treated teeth in these groups a dentin chip plug had been made, although care had been taken to avoid this. It is suggested that a plug of dentin chips is well tolerated by the tissues and may present an effective barrier in the apical part of the root canal, facilitating the accomplishment of a well-condensed, tightly sealing root filling.

Animals↗
PubMed2005

Mass spectrometric analysis of affinity-captured proteins on a dendrimer-based immunosensing surface: investigation of on-chip proteolytic digestion.

The monolayer of fourth-generation poly(amidoamine) dendrimers was adopted to construct the immunoaffinity surface of an antibody layer. The antibody layer as a bait on the dendrimer monolayer was found to result in high binding capacity of antigenic proteins and a reliable detection. The affinity-captured protein at the immunosensing surface was subjected to direct on-chip tryptic digestion, and the resulting proteolytic peptides were analyzed by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The performance of the on-chip digestion procedure was investigated with respect to the ratio of trypsin to protein, digestion time, composition of a reaction buffer, and the amount of affinity-captured protein on a surface. Addition of a water-miscible organic solvent to a reaction buffer had no significant effect on the digestion efficiency under the optimized digestion conditions. The on-chip digestion method identified the affinity-captured bovine serum albumin (BSA), lysozyme, and ferritin at the level of around 100 fmol. Interestingly, the detected number of peptide hits through the on-chip digestion was almost similar regardless of the amount of captured protein ranging from low- to high-femtomole levels, whereas the efficiency of in-solution digestion decreased significantly as the amount of protein decreased to low-femtomole levels. The structural alignment of the peptide fragments from on-chip-digested BSA revealed that the limited exterior of the captured protein is subjected to attack by trypsin. The established detection procedures enabled the identification of BSA in the biological mixtures at the level of 0.1 ng/mL. The use of antibodies against the proteins involved in the metabolic pathway of L-threonine in Escherichia coli also led to discrimination of the respective target proteins from cell lysates.

Amino Acid Sequence↗
PubMed2006

Polymerase chain reaction of 2-kb cyanobacterial gene and human anti-alpha1-chymotrypsin gene from genomic DNA on the In-Check single-use microfabricated silicon chip.

The microfabricated chip is a promising format for automating and miniaturizing the multiple steps of genotyping. We tested an innovative silicon biochip (In-Check Lab-on-Chip; STMicroelectronics, Agrate Brianza, Italy) designed for polymerase chain reaction (PCR) analysis of complex biological samples. The chip is mounted on a 1x3-in(2). plastic slide that provides the necessary mechanical, thermal, electrical, and fluidic connections. A temperature control system drives the chip to the desired temperatures, and a graphical user interface allows experimenters to define cycling conditions and monitor reactions in real time. During thermal cycling, we recorded a cooling rate of 3.2 degrees C/s and a heating rate of 11 degrees C/s. The temperature maintained at each thermal plateau was within 0.13 degrees C of the programmed temperature at three sensors. From 0.5 ng/microl genomic DNA, the In-Check device successfully amplified the 2060-bp cyanobacterial 16S rRNA gene and the 330-bp human anti-alpha(1)-chymotrypsin gene. The shortest PCR protocol that produced an amplicon by capillary electrophoresis comprised 30 cycles and was 22.5 min long. These thermal cycling characteristics suggest that the In-Check device will permit future development of a genotyping lab-on-a-chip device, yielding results in a short time from a limited amount of biological starting material.

Cyanobacteria↗
PubMed2004

Co-chaperone CHIP associates with mutant Cu/Zn-superoxide dismutase proteins linked to familial amyotrophic lateral sclerosis and promotes their degradation by proteasomes.

Although the ubiquitin-proteasome system and the molecular chaperones are implicated to play an important role in pathogenesis of familial amyotrophic lateral sclerosis (FALS) caused by mutations in Cu/Zn-superoxide dismutase (SOD1), the mechanism underlying the causes of this fatal disease is still poorly understood. Here we found that co-chaperone CHIP (carboxyl terminus of Hsc70-interacting protein), together with molecular chaperones Hsc70/Hsp70 and Hsp90, associates with FALS-linked mutant SOD1 proteins in cultured human cells. S5a subunit of 26S proteasomes, which recognizes polyubiquitylated proteins, also interacts with mutant SOD1 proteins. Over-expression of CHIP leads to the reduction in cellular levels of mutant SOD1 as well as the suppression of cytotoxicity induced by mutant SOD1. Unusually, rather than increasing the level of poly-ubiquitylated SOD1, over-expressed CHIP alters the ubiquitylation pattern of mutant SOD1 proteins. Both down-regulation and ubiquitylation of mutant SOD1 are greatly reduced by a mutant CHIP protein lacking U-box domain. Taken together, these results suggest that co-chaperone CHIP, possibly with another E3 ligase(s), modulates the ubiquitylation of mutant SOD1 and renders them more susceptible for proteasomal degradation.

Amyotrophic Lateral Sclerosis↗
PubMed2004

Immobilization of metallothionein as a sensitive biosensor chip for the detection of metal ions by surface plasmon resonance.

A biosensor based on mammalian metallothionein (MT) for the detection of metal ions was developed and characterized. MT was immobilized onto a carboxymethylated dextran matrix as a biosensor for the detection of metal ions by surface plasmon resonance (SPR). The optimal pH for the immobilization step was determined to be 4. The temperature for the analysis was also defined, and the highest interaction was observed at 30 degrees C. The MT sensor chip binds cadmium (Cd), zinc (Zn) or nickel (Ni), but not magnesium (Mg), manganese (Mn) and calcium (Ca). Calibration curves for the quantification of metal ions showed excellent linearity. The sensitivity for metal detection is at the micromolar level. The interaction between the metal ions and the sensor chip is influenced significantly by the presence of NaCl, Tween 20 and the pH of the reaction buffer. By decreasing the NaCl in the reaction buffer to 1 mM, the MT chip effectively differentiates cadmium from zinc and nickel. Kinetic parameters of the metal-MT interactions were also determined by using this chip. The binding affinity between the metal ions and the immobilized MT follows the order of cadmium > zinc > nickel, which is the same as that determined for MT in solution. Thus, the MT chip can be an effective biosensor for the detection and measurement of several metal ions.

Adsorption↗
PubMed2005

Fabrication and characteristics of MOSFET protein chip for detection of ribosomal protein.

A metal oxide silicon field effect transistor (MOSFET) protein chip for the easy detection of protein was fabricated and its characteristics were investigated. Generally, the drain current of the MOSFET is varied by the gate potential. It is expected that the formation of an antibody-antigen complex on the gate of MOSFET would lead to a detectable change in the charge distribution and thus, directly modulate the drain current of MOSFET. As such, the drain current of the MOSFET protein chip can be varied by ribosomal proteins absorbed by the self-assembled monolayer (SAM) immobilized on the gate (Au) surface, as ribosomal protein has positive charge, and these current variations then used as the response of the protein chip. The gate of MOSFET protein chip is not directly biased by an external voltage source, so called open gate or floating gate MOSFET, but rather chemically modified by immobilized molecular receptors called self-assembled monolayer (SAM). In our experiments, the current variation in the proposed protein chip was about 8% with a protein concentration of 0.7 mM. As the protein concentration increased, the drain current also gradually increased. In addition, there were some drift of the drain current in the device. It is considered that these drift might be caused by the drift from the MOSFET itself or protein absorption procedures that are relied on the facile attachment of thiol (-S) ligands to the gate (Au) surface. We verified the formation of SAM on the gold surface and the absorption of protein through the surface plasmon resonance (SPR) measurement.

Biosensing Techniques↗
PubMed2006

Integration of a surface acoustic wave biosensor in a microfluidic polymer chip.

SAW devices based on horizontally polarized surface shear waves (HPSSW) enable label-free, sensitive and cost-effective detection of biomolecules in real time. It is known that small sampling volumes with low inner surface areas and minimal mechanical stress arising from sealing elements of miniaturized sampling chambers are important in this field. Here, we present a new approach to integrate SAW devices with sampling chamber. The sensor device is encapsulated within a polymer chip containing fluid channel and contact points for fluidic and electric connections. The chip volume is only 0.9 microl. The polymeric encapsulation was performed tailor-made by Rapid Micro Product Development 3Dimensional Chip-Size-Packaging (RMPD 3D-CSP), a 3D photopolymerisation process. The polymer housing serves as tight and durable package for HPSSW biosensors and allows the use of the complete chips as disposables. Preliminary experiments with these microfluidic chips are shown to characterise the performance for their future applications as generic bioanalytical micro devices.

Acoustics↗