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At least 721 records · Page 40Linked to original sources
PubMed2006

Effects of storage temperature on the contents of sugars and free amino acids in tubers from different potato cultivars and acrylamide in chips.

To clarify the effects of storage temperature on potato components and acrylamide in chips, tubers from five cultivars were stored at various temperatures (2, 6, 8, 10, and 18 degrees C) for 18 weeks, and the contents of sugars, free amino acids in tubers, and acrylamide in chips after frying were analyzed. At temperatures lower than 8 degrees C, the contents of reducing sugars increased markedly in all cultivars, with similar increases in the acrylamide level and dark brown chip color. Free amino acids showed little change at the storage temperatures tested and varied within certain ranges characteristic of each cultivar. The contents of reducing sugars correlated well with the acrylamide level when the fructose/asparagine molar ratio in the tubers was <2. When the fructose/asparagine ratio was >2 by low-temperature storage, the asparagine content, rather than the reducing sugar content, was found to be the limiting factor for acrylamide formation.

Acrylamide↗
PubMed2005

High-performance optical code generation and recognition by use of a 511-chip, 640-Gchip/s phase-shifted superstructured fiber Bragg grating.

The generation and recognition of a record-length 511-chip optical code is experimentally demonstrated by use of a superstructured fiber Bragg grating (SSFBG) with a chip rate of 640 Gchips/s. Very high reflectivity (92%) is achieved with high-quality correlation properties. The temperature deviation tolerance is approximately +/- 0.3 degrees C, which is within the package's temperature stability range (+/- 0.1 degrees C). Experimental results show good agreement with the theory. They indicate the SSFBG's potential for processing a long optical code with an ultrahigh chip rate, which could significantly improve the system's performance.

Journal Article↗
PubMed2005

Clinically related protein-peptide interactions monitored in real time on novel peptide chips by surface plasmon resonance imaging.

BACKGROUND: Developing rapid, high-throughput assays for detecting and characterizing protein-protein interactions is a great challenge in the postgenomic era. We have developed a new method that allows parallel analysis of multiple analytes in biological fluids and is suitable for biological and medical studies. METHODS: This technology for studying peptide-antibody interactions is based on polypyrrole-peptide chips and surface plasmon resonance imaging (SPRi). We generated a chip bearing a large panel of peptide probes by successive electro-directed copolymerizations of pyrrole-peptide conjugates on a gold surface. RESULTS: We provide evidence that (a) the signal produced by antibody binding is highly specific; (b) the detected signal specifically reflects the antibody concentration of the tested solution in a dose-dependent manner; (c) this technique is appropriate for analyzing complex media such as undiluted sera, a novelty with respect to previous techniques; and (d) correlation between classic ELISA results and the SPRi signal is good (P = 0.008). We also validated this system in a medical model by detecting anti-hepatitis C antibodies in patient-derived sera. CONCLUSION: Because of its characteristics (easy preparation of the peptide chip; high-throughput, label-free, real-time detection; high specificity; and low background), this technology is suitable for screening biological samples and for large-scale studies.

Binding Sites, Antibody↗
PubMed2006

Chip electrophoresis as a method for quantifying total microalbuminuria.

BACKGROUND: Microalbuminuria is an important prognostic marker in diabetic nephropathy and cardiovascular disease. Initially, most commercial assays used immunoreactivity to quantify microalbuminuria; however, size-exclusion HPLC demonstrated the existence of nonimmunoreactive forms of albumin that may not be detected by immunoassay. Recent liquid chromatography tandem mass spectrometry analyses suggested that size-exclusion HPLC gave higher results attributable to other urine proteins coeluting with albumin. We describe an assay that measures total microalbuminuria (immunoreactive and nonimmunoreactive) without any discernable interference from other common urine proteins. METHODS: We used an automated chip electrophoresis system that utilized microfluidic separation technology and fluorescent sample detection. Each albumin specimen was mixed with the manufacturer's sample buffer in addition to a chicken albumin internal calibrator and then electrophoresed without additional reducing agents. RESULTS: With variable concentrations of bovine serum albumin normalized to a chicken albumin internal calibrator, the electrophoresis system was best fit with a polynomial (R2=0.9997; concentration range, 5-300 mg/L). The lower limit of detection was 5 mg/L. Interchip and intrachip variation studies conducted on patient urine demonstrated CVs of 3%-13%. The introduction of potentially interfering agents (i.e., molecular analytes, nonalbumin proteins) did not alter precision. Compared with immunoassay, the chip electrophoresis identified higher microalbuminuria concentrations in all urine samples. The method also clearly resolved the albumin peak from interfering proteins. CONCLUSIONS: Unlike immunoassay, chip electrophoresis can detect both immunoreactive and nonimmunoreactive forms of albumin. This system is a simple, robust method to quantify microalbuminuria with good sensitivity, precision, and accuracy.

Albuminuria↗
PubMed2001

Cambridge Healthtech Institute's Third Annual Conference on Lab-on-a-Chip and Microarrays. 22-24 January 2001, Zurich, Switzerland.

Cambridge Healthtech Institute's Third Annual Conference on Lab-on-a-Chip and Microarray technology covered the latest advances in this technology and applications in life sciences. Highlights of the meetings are reported briefly with emphasis on applications in genomics, drug discovery and molecular diagnostics. There was an emphasis on microfluidics because of the wide applications in laboratory and drug discovery. The lab-on-a-chip provides the facilities of a complete laboratory in a hand-held miniature device. Several microarray systems have been used for hybridisation and detection techniques. Oligonucleotide scanning arrays provide a versatile tool for the analysis of nucleic acid interactions and provide a platform for improving the array-based methods for investigation of antisense therapeutics. A method for analysing combinatorial DNA arrays using oligonucleotide-modified gold nanoparticle probes and a conventional scanner has considerable potential in molecular diagnostics. Various applications of microarray technology for high-throughput screening in drug discovery and single nucleotide polymorphisms (SNP) analysis were discussed. Protein chips have important applications in proteomics. With the considerable amount of data generated by the different technologies using microarrays, it is obvious that the reading of the information and its interpretation and management through the use of bioinformatics is essential. Various techniques for data analysis were presented. Biochip and microarray technology has an essential role to play in the evolving trends in healthcare, which integrate diagnosis with prevention/treatment and emphasise personalised medicines.

Computational Biology↗
PubMed2005

Automated chip-based device for simple and fast nucleic acid amplification.

A chip-based PCR device is presented that is capable of rapid temperature ramping and handling sample volumes in the microliter range. The PCR chip comprises a microchannel thermally connected to three temperature zones. Inside this microchannel, the PCR sample plug is driven and precisely positioned by a ferrofluidic actuator for more than 40 cycles within 5 min. Computer simulations predict that the sample plugs are thermally equilibrated on a time scale of some 10 ms when transported to a different temperature zone. Hence, the thermal limitations on the cycle speed of the system are considerably reduced compared with conventional cyclers. The system was developed on a modular platform suitable for handling further microfluidic tasks such as DNA extraction and preparation of the PCR mix. Thus, the aspired chip-based platform represents not only a PCR system but a complete analysis system, from the injection of a patient's blood sample to its final appraisal.

Automation↗
PubMed2002

The effect of subgingival controlled-release delivery of chlorhexidine chip on clinical parameters and matrix metalloproteinase-8 levels in gingival crevicular fluid.

BACKGROUND: The present study evaluated the efficacy of controlled-release delivery of chlorhexidine gluconate (CHX) on clinical parameters and on gingival crevicular fluid (GCF) matrix metalloproteinase (MMP)-8 levels in chronic periodontitis patients. METHODS: Twenty patients with chronic periodontitis were screened for 6 months. Two interproximal sites were selected from mesial surfaces of anterior teeth with probing depths of 6 to 8 mm that bled on probing in each patient. There were at least 2 teeth between the selected sites. CHX chip was inserted into a randomly selected site following scaling and root planing (SRP+CHX), while the other selected site received only SRP in each patient. Probing depth (PD), clinical attachment level (CAL), plaque index (PI), and papilla bleeding index (PBI) were recorded at baseline and at 1, 3, and 6 months. GCF MMP-8 levels were analyzed at baseline; 2 and 10 days; and at 1, 3, and 6 months by immunofluorometric assay (IFMA). RESULTS: At baseline, there were no statistically significant differences in the mean PD, CAL, PBI, and PI scores between SRP+CHX and SRP alone groups. At 1, 3, and 6 months, all clinical parameters in each group significantly decreased (P <0.0167) when compared to baseline. The reduction of PD and improvement in CAL were higher in the SRP+CHX group compared to SRP alone at 3 and 6 months. However, the differences between the 2 groups were not statistically significant. PBI and PI scores were not significantly different between SRP+CHX and SRP alone groups at any visit. GCF MMP-8 levels were similar in both groups at baseline. Intragroup analysis showed significant decreases in the GCF MMP-8 level for the SRP+CHX group between baseline and 1, 3, and 6 months (P<0.01). Intergroup analysis demonstrated significantly lower mean levels of GCF MMP-8 at 1 month in the SRP+CHX group compared to the SRP alone group (P <0.05). CONCLUSIONS: These data suggest that CHX chip application following SRP is beneficial in improving periodontal parameters and reducing GCF MMP-8 levels for 6 months' duration. The use of a chairside MMP-8 dipstick periodontitis test might be a useful adjunctive diagnostic tool when monitoring the course of CHX chip treatment.

Adult↗
PubMed2004

An application of plastic microchannel-microheater chips to a thermal synthetic reaction.

Polystyrol microchannel-microheater chips were fabricated on the basis of imprinting and photolithography techniques. The solution (i.e., methanol) temperature in the vicinity of the microheater (width = 100 or 200 microm and length = 100 microm) integrated in the channel (width = 100 microm and depth = 20 microm) was evaluated on the basis of the temperature-dependent fluorescence lifetime of Rhodamine B as a function of a flow rate and the voltage applied to the heater. The study demonstrated that the fabricated chip acted certainly as a microheater. The chip was then applied to the thermal reaction between benzaldehyde and malononitrile in methanol. Under optimum conditions, benzilidenemalononitrile as the product of the reaction was obtained in a 96% yield with the reaction time of 84 s.

Journal Article↗
PubMed2001

Protein chips based on recombinant antibody fragments: a highly sensitive approach as detected by mass spectrometry.

With the human genome in a first sequence draft and several other genomes being finished this year, the existing information gap between genomics and proteomics is becoming increasingly evident. The analysis of the proteome is, however, much more complicated because the synthesis and structural requirements of functional proteins are different from the easily handled oligonucleotides, for which a first analytical breakthrough already has come in the use of DNA chips. In comparison with the DNA microarrays, the protein arrays, or protein chips, offer the distinct possibility of developing a rapid global analysis of the entire proteome. Thus, the concept of comparing proteomic maps of healthy and diseased cells may allow us to understand cell signaling and metabolic pathways and will form a novel base for pharmaceutical companies to develop future therapeutics much more rapidly. This report demonstrates the possibilities of designing protein chips based on specially constructed, small recombinant antibody fragments using nano-structure surfaces with biocompatible characteristics, resulting in sensitive detection in the 600-amol range. The assay readout allows the determination of single or multiple antigen-antibody interactions. Mass identity of the antigens, currently with a resolution of 8000, enables the detection of structural modifications of single proteins.

Antibodies↗
PubMed2004

In vivo analysis of DNA methylation patterns recognized by specific proteins: coupling CHIP and bisulfite analysis.

The three-way connection between DNA methylation, chromatin configuration, and transcriptional regulation is under increasing attention, but the fine rules governing the epigenetic control are still poorly understood. In several studies, the authors have concluded that the methylation status of CpG sites could be critical for the binding of factors to DNA and, consequently, for chromatin conformation. We tested the possibility that a novel technical approach combining chromatin immunoprecipitation and bisulfite genomic sequencing analysis (ChIP-BA) could provide useful information on the role of specific CpG methylation patterns in driving the association in vivo of proteins to given genomic regions. Our results show that ChIP-BA permits the establishment in vivo of the methylation patterns required for the binding of a methyl-CpG binding protein and, in addition, can potentially identify methylation patterns that do not allow a protein to bind specific genomic regions. Possible fields of application are discussed. We believe that wide use of ChIP-BA could make possible the exploration of a novel aspect of the intricate epigenetic web.

Base Sequence↗
PubMed2006

Novel probes for protein chip applications.

Protein microarrays (protein chips), due to their high throughput, have great potential to reduce the cycle time of drug discovery and to improve the efficiency of medical diagnostics. A great deal of effort has been made to facilitate the development of protein chips, such as the antibody microarrays. High-throughput fabrication of purified high-affinity probes is now one of the bottlenecks for protein microarrays. We discuss here three novel strategies to fabricate probes, namely, single chain antibodies displayed by phage, protein-oligonucleotide conjugates, and aptamers, which are promising in the protein chip technology.

Antibodies↗
PubMed2001

[Impact of DNA chips on haematological oncology]

As the Human Genome Project hurtles towards completion, DNA microarray technology offers the potential to open wide new windows into the study of genome complexity. DNA chips can be used for many different purposes, most prominently to measure levels of gene expression (messenger RNA abundance) for tens of thousands of genes simultaneously. But how much of this data is useful and is some superfluous? Can array data be used to identify a handful of critical genes that will lead to a more detailed taxonomy of haematological malignancies and can this or similar array data be used to predict clinical outcome? It is still too early to predict what the ultimate impact of DNA chips will be on our understanding of cancer biology. There are many critically important questions about this new field that are yet unaddressed. By the publication of this article, it is hoped that the technology of DNA chips will be opened up and demystified, and that additional opportunities for creative exploration will be catalysed.

Journal Article↗
PubMedDate not supplied

Combinatorial materials synthesis and high-throughput screening: an integrated materials chip approach to mapping phase diagrams and discovery and optimization of functional materials.

Combinatorial materials synthesis methods and high-throughput evaluation techniques have been developed to accelerate the process of materials discovery and optimization and phase-diagram mapping. Analogous to integrated circuit chips, integrated materials chips containing thousands of discrete different compositions or continuous phase diagrams, often in the form of high-quality epitaxial thin films, can be fabricated and screened for interesting properties. Microspot x-ray method, various optical measurement techniques, and a novel evanescent microwave microscope have been used to characterize the structural, optical, magnetic, and electrical properties of samples on the materials chips. These techniques are routinely used to discover/optimize and map phase diagrams of ferroelectric, dielectric, optical, magnetic, and superconducting materials.

Combinatorial Chemistry Techniques↗
PubMedDate not supplied

Application of modified CHIP-AE in a vocational high school.

Adolescent health behaviors tend to cluster and vary by such factors as grade, age, and racial/ethnic background. A population-based instrument was needed to assess health behaviors of the students in a vocational high school in the City of Chicago. To reduce respondent burden, Child Health and Illness Profile--Adolescent Edition (CHIP-AE) was modified by omitting seven subdomains. Ninety-three boys and 245 girls voluntarily participated in the study. Pearson correlation coefficients, MANOVA, and ANOVA were used in data analysis. Modified CHIP-AE was found to have acceptable reliability and detect the expected differences of adolescent health behaviors by gender and age. Modified CHIP-AE can be used to assess adolescent health behaviors in an urban vocational high school. It can also be used to target the subgroups of students with specific needs for health services.

Adolescent↗
PubMed2001

K-ras mutation detection by hybridization to a polypyrrole DNA chip.

BACKGROUND: Detection of mutations in cancer-related genes is of major importance for both basic knowledge and clinical practice. Several strategies have been developed to diagnose these alterations. We describe a method based on polypyrrole DNA chip technology to detect K-ras gene mutations in tumors. METHODS: An oligodeoxynucleotide array was constructed on a silicon device by copolymerization of 5'-pyrrole-labeled oligodeoxynucleotides and pyrrole. The samples to be analyzed were then amplified by PCR, and the single-stranded biotin-labeled amplified DNA was specifically hybridized to the addressed probes. Perfectly matched duplexes were detected by fluorescence microscopy using R-phycoerythrin as the detection label. The developed methodology was applied to genotype assignment of K-ras in human samples. The genotypes of 75 DNA genomic samples from colorectal cancer patients were analyzed side by side using direct DNA sequencing and a polypyrrole DNA chip. RESULTS: The chip method unequivocally defined all of the genotypes. Mutations present at <10% of the wild-type DNA concentration could be distinguished. CONCLUSIONS: This probe array assay is a rapid and reliable procedure that may be used to detect mutations.

Colorectal Neoplasms↗
PubMedDate not supplied

[Use of the technology of the genetic chip to study of the nitric oxide synthase].

INTRODUCTION: The end of our century has been characterized by a quick scientific and technological growth. Among other, the brain, the human genome project and the computer science, they are some of the numerous fields that characterize this revolution. DEVELOPMENT: In the following work, we will show as these three fields of the knowledge have converged in a new area of the science denominated technology of the gene chip or microarrays. Although this methodology would allow the study of thousands of genes in one chip, in the following work we will center ourselves in its potential application for the study of the enzyme nitric oxide synthase (NOS), which is responsible for the production of the nitric oxide (NO). The technical base of this system is to be able to synthesize chains of DNA in a chip, which will be hybridized with the sample of interest that in turn are usually marked with fluorescent nucleotides. The results are analyzed using a sophisticated image analysis system. The relative estimate of the quantity of existent messenger in each sample will come determined by the intensity of the fluorescence, and for its comparison with internal controls. The discovery of at least three genes that are coded for NOS, as well as that of numerous allelic variations will allow a more exhaustive study of this molecule, which has been recognized by their vital importance. CONCLUSION: In this review we will put in perspective the utility of this technology in the genetic study of the enzyme NOS, and its utility for the understanding of the pathophysiology of some neurological illnesses.

Brain↗
PubMed2001

[The efficacy of the chlorhexidine chip following scaling and root planing (SRP) and compared to SRP alone].

OBJECTIVE: To evaluate the clinical efficacy and safety of the adjunctive use of Chlorhexidine Chip (CHX; commercial name, Perio Chip) following scaling and root planing (SRP) in periodontitis. METHODS: One center, blinded, randomized, split-mouth and active control study was designed. Sixty-five adult periodontitis patients were enrolled into the baseline after SRP. Each subject had at least one tooth with pocket depth of 5 mm or more and bleeding on probing (BOP) in each side of the mouth. Then the tooth was selected as a target and its parameters of probing depth (PD), attachment loss (AL), BOP, gingival index (GI), plaque index (PI) and staining index (SI) were recorded. Each side of mouth was randomly assigned to one of two treatments--drug placement after SRP or SRP alone. All the adverse events and parameters were recorded at time of 3-month, 6-month and meanwhile the patients received oral hygiene instruction and scaling. The same was conducted at 6-week, 4.5-month except for recording of parameters and scaling of the target teeth. RESULTS: Reduction of PD and gain of attachment at 6-month in group of SRP plus CHX (1.32 mm, 0.94 mm) were significantly higher than those in group of SRP alone (0.77 mm, 0.40 mm) (P < 0.001). Forty-four point six percent (44.6%) of patients reflected adverse reactions related to drug placement. Toothaches, the main reactions, were mild to moderate in nature and spontaneously resolved within 2-4 days. CONCLUSIONS: The chlorhexidine chip is indeed a safe and effective control-delivered drug for topical use when patient in his supportive periodontal therapy.

Adult↗
PubMed2000

DNA Microarray Chips Made on Surface of Ceramic Slides.

As a novel technology, DNA microarray chips are being used in gene detections. To make DNA chips capable of multiple probing, ceramic slides, instead of silicon wafer or glass slides, were used as the substrate upon which DNA microarray are deposited. Our study indicates that the ceramic DNA microarray chips can be applied to multiple hybridization and detection procedures, showing high specificity. The advantages in using ceramic substrates are discussed.

Journal Article↗