Biomedical subjects

Min Chen

Publications and source records attributed to Min Chen.

228 records · Page 13Linked to original sources

PubMed2002

[In vitro study of the apoptosis effect of DNR on HL-60 cells and its relationship with ROS, CER and NF-kappaB].

OBJECTIVE: To study the effect of DNR on HL-60 cells apoptosis in vitro and the related mechanism. METHODS: The apoptosis of HL-60 was observed by microscope, flow cytometry (FCM) and DNA electrophoresis and various apoptosis-associated proteins expression by immunocytochemistry (IC) and FCM assays; the changes of apoptosis in HL-60 cells treated with DNR or suppressors PDTC or FB1 were also observed. RESULTS: When treated with 0.2 approximately 2.0 micro mol/L DNR, the percentage of apoptotic HL-60 cells increased with the dose increasing and the time extending, and the typical apoptotic cells and the appearance of apoptotic DNA ladder were observed. It was shown that after treatment with 1 micro mol/L DNR, the fluorescence intensity index (FI) of both bcl-2 and c-myc in HL-60 cells decreased, the FI of Bax, caspase-3 increased at 2 h, but decreased at 5 h, the FI of NF-kappaB increased. After adding PDTC, the apoptosis percentage of HL-60 cells decreased, but FB1 didn't present these effect. CONCLUSION: It suggested from the results that at certain concentration, DNR can induce the apoptosis of HL-60 cells in vitro. The mechanism was supposed by suppressing the expression of bcl-2 and c-myc and activating the expression of Bax and caspase-3, NF-kappaB and ROS had the marked correlation with the apoptosis process, but the ceramide synthase wasn't associated with it.

Apoptosis↗

PubMed2002

[Antigens of antineutrophil cytoplasmic autoantibodies in recognizing a novel neutrophil granule antigen in lupus nephritis and its association with photosensitivity and oral ulceration].

OBJECTIVE: To investigate whether there are some unknown target antigens of antineutrophil cytoplasmic autoantibodies (ANCA) in patients with lupus nephritis (LN) and the prevalence and the clinical significance of these unknown target antigens. METHODS: Serum was collected from 72 renal-biopsy-proven lupus nephritis (LN) patients. Mixed neutrophil granules were separated from normal human peripheral neutrophils and soluble acid extracts in non-reducing conditions were used as antigens in Western-blot analysis to detect ANCA in the serum sample of LN patients. RESULTS: Serum from seme LN patients could blot a few bands. Interestingly, serum from 14/72 (19.4%) of the patients recognized a novel 69,000 protein band and that from 10/72 (13.9%) sera recognized a 55,000 protein band that might be the bactericidal/permeability-increasing protein (BPI). The 69,000 target antigen was different from the known target ANCA antigens such as cathepsin G and lactoferrin. Further study revealed that the percentages of patients with photosensitivity and oral ulcer in anti-69,000 autoantibody positive group were significantly higher than those in the anti-69,000 autoantibody negative group (57.1% vs 12.1%, P < 0.005, and 50.0% vs 17.2%, P < 0.05, respectively). CONCLUSIONS: A novel 69,000 protein in human neutrophil granules is identified as a target antigen of ANCA in LN patients. The anti-69,000 autoantibodies may be associated with photosensitivity and oral ulcer in LN patients.

Adolescent↗

PubMed2002

[Influences of diet and nutrition on obesity of pre-school children].

OBJECTIVE: To study diet and nutrition on obesity of pre-school children. METHODS: Applying food weighing and food record method, to understand the diet situation of toddler at kindergarten and plus home in a week. RESULTS: The energy intake in obese children was 1557.0 kcal that was higher than 1442.4 kcal in the control group (P < 0.001). Calculating the intake of nutrients, we found that protein, fat, and CHO in obese children were higher than in the control group. Significant difference in fat and CHO was detected between the two groups. CONCLUSION: Dietary fat intake is a risk factor for childhood obesity. To prevent childhood obesity, parents need to help children to develop good food habit.

Child↗

PubMed2002

[Genotyping of hepatitis B virus and clinical investigation].

OBJECTIVE: To investigate the distribution of HBV genotypes in Changzhou area and to clarify the genotype-related difference in the liver function, the level of HBV DNA and the long-term effect of lamivudine in the pathogenicity of HBV. METHODS: Nested PCR and sequence analysis were conducted in 14 acute hepatitis (AH), 104 chronic hepatitis (CH), and 28 liver cirrhosis or hepatocellular carcinoma (LC/HCC) patients. RESULTS: One hundred and forty six samples were positive for HBV DNA, and 51 samples were classified as genotype B (34.9%), 95 samples were classified as genotype C, serum ALT value was 383.8 +/- 335.7 IU in patients with HBV genotypes B, and 364.3 +/- 333.7 IU in genotypes C, HBV DNA value was 10(7.795 +/- 1.22) copies/ml in genotypes B and 10(7.69 +/0- 1.19) copies/ml in genotypes C, and there were 36 and 64 HBeAg positive cases in patients with genotypes B and C; there were no significant difference on the level of ALT, HBV DNA and the expression of HBeAg (P>0.05), but genotype C in LC/HCC was higher than CH (P<0.01). Twenty three genotype B and forty five genotype C patients received lamivudine treatment, after 48 weeks, 18 genotype B and 14 genotype C patients had higher ALT or HBV DNA positive. CONCLUSIONS: These results indicate that genotype B and C existing Changzhou area; genotype C is associated with the development of severe liver disease and better therapeutic effect could be obtained in the patients with genotype C.

Adult↗

PubMed2002

[Echolocation sound waves, morphological features and foraging strategies in Hipposideros pratti].

Studies on the echolocation sound waves in different states (flying and hanging), morphological features and ecological processes (foraging strategies, foraging habitat and diet type) of Hipposideros pratti showed that H. pratti had CF (constant frequency)-FM (frequency modulated) echolocation sounds. There were some differences in dominant frequency (caused by Doppler compensating effect), pulse repetition rate, pulse duration and interpulse interval between the bats at flying and hanging. The dominant frequency, FM bandwidth, pulse duration and interpulse interval were lower, while the pulse repetition rate and duty cycle were higher at flying than at hanging. All the differences indicated that H. pratti could adopt specific echolocation sounds to adapt to specific environments and conditions to detect, approach and capture their preys successfully. On the basis of echolocation sound and field observation, it was concluded that H. pratti might search the preys at flying in the period of insect fastigium, and after the period, it might search the targets at hanging. The foraging habitat was near the tree crowns, and the preys consisted mainly of relatively large insects, such as beetles.

Animals↗

PubMed2002

[Analysis of terpineol and improvement of technology process in terpineol production].

A method for the separation and determination of terpineol oil by temperature programming capillary gas chromatography has been established. An OV-1 fused silica capillary column (30 m x 0.32 mm i.d. x 0.25 microns) was used with a temperature increase rates of 1.5 degrees C/min from 70 degrees C to 100 degrees C, 5 degrees C/min from 100 degrees C to 160 degrees C, 10 degrees C/min from 160 degrees C to 220 degrees C and then hold for 2 min. The main chemical components and their relative contents of the terpineol oil, terpinene oil, red and yellow oils of middle oils in the terpineol production and natural terpineol were analyzed by capillary gas chromatography-Fourier transform infrared spectrometry (GC-FTIR) and gas chromatography-mass spectrometry (GC-MS). The typical chromatograms of these oils are given. It has offered the information of the boiling points of the chemical compounds, and it is helpful to reutilize them after their separation by rectification. The results showed that the main compounds of the heavy cut of terpineol were longifolene and beta-caryophyllene. They are from the raw material, terpinene oil. The main compounds in the natural terpineol oil were eucalyptol, trans-4-thujanol, p-isopropenyl toluene, cis-4-thujanol, linalool, camphor, borneol, 4-terpineol, alpha-terpineol and safrole. The contents of beta-terpineol and gamma-terpineol were not so high as in synthetic terpineol.

Cyclohexane Monoterpenes↗

PubMedDate not supplied

Feature aligned volume manipulation for illustration and visualization.

In this paper we describe a GPU-based technique for creating illustrative visualization through interactive manipulation of volumetric models. It is partly inspired by medical illustrations, where it is common to depict cuts and deformation in order to provide a better understanding of anatomical and biological structures or surgical processes, and partly motivated by the need for a real-time solution that supports the specification and visualization of such illustrative manipulation. We propose two new feature-aligned techniques, namely surface alignment and segment alignment, and compare them with the axis-aligned techniques which was reported in previous work on volume manipulation. We also present a mechanism for defining features using texture volumes, and methods for computing correct normals for the deformed volume in respect to different alignments. We describe a GPU-based implementation to achieve real-time performance of the techniques and a collection of manipulation operators including peelers, retractors, pliers and dilators which are adaptations of the metaphors and tools used in surgical procedures and medical illustrations. Our approach is directly applicable in medical and biological illustration, and we demonstrate how it works as an interactive tool for focus+context visualization, as well as a generic technique for volume graphics.

Algorithms↗

PubMedDate not supplied

Visual signatures in video visualization.

Video visualization is a computation process that extracts meaningful information from original video data sets and conveys the extracted information to users in appropriate visual representations. This paper presents a broad treatment of the subject, following a typical research pipeline involving concept formulation, system development, a path-finding user study, and a field trial with real application data. In particular, we have conducted a fundamental study on the visualization of motion events in videos. We have, for the first time, deployed flow visualization techniques in video visualization. We have compared the effectiveness of different abstract visual representations of videos. We have conducted a user study to examine whether users are able to learn to recognize visual signatures of motions, and to assist in the evaluation of different visualization techniques. We have applied our understanding and the developed techniques to a set of application video clips. Our study has demonstrated that video visualization is both technically feasible and cost-effective. It has provided the first set of evidence confirming that ordinary users can be accustomed to the visual features depicted in video visualizations, and can learn to recognize visual signatures of a variety of motion events.

Algorithms↗

PubMedDate not supplied

Volume splitting and its applications.

Splitting a volumetric object is a useful operation in volume graphics and its applications, but is not widely supported by existing systems for volume-based modeling and rendering. In this paper, we present an investigation into two main algorithmic approaches, namely, explicit and implicit splitting, for modeling and rendering splitting actions. We consider a generalized notion based on scalar fields, which encompasses discrete specifications (e.g., volume data sets) as well as procedural specifications (e.g., hypertextures) of volumetric objects. We examine the correctness, effectiveness, efficiency, and deficiencies of each approach in specifying and controlling a spatial and temporal specification of splitting. We propose methods for implementing these approaches and for overcoming their deficiencies. We present a modeling tool for creating specifications of splitting functions, and describe the use of volume scene graphs for facilitating direct rendering of volume splitting. We demonstrate the use of these approaches with examples of volume visualization, medical illustration, volume animation, and special effects.

Algorithms↗

PubMedDate not supplied

Angiotensin II-mediated endothelial dysfunction: role of poly(ADP-ribose) polymerase activation.

Angiotensin II (AII) contributes to the pathogenesis of many cardiovascular disorders. Oxidant-mediated activation of poly(adenosine diphosphate-ribose) polymerase (PARP) plays a role in the development of endothelial dysfunction and the pathogenesis of various cardiovascular diseases. We have investigated whether activation of the nuclear enzyme PARP contributes to the development of AII-induced endothelial dysfunction. AII in cultured endothelial cells induced DNA single-strand breakage and dose-dependently activated PARP, which was inhibited by the AII subtype 1 receptor antagonist, losartan; the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, apocynin; and the nitric oxide synthase inhibitor, N-nitro-L-arginine methyl ester. Infusion of sub-pressor doses of AII to rats for 7 to 14 d induced the development of endothelial dysfunction ex vivo. The PARP inhibitors PJ34 or INO-1001 prevented the development of the endothelial dysfunction and restored normal endothelial function. Similarly, PARP-deficient mice infused with AII for 7 d were found resistant to the AII-induced development of endothelial dysfunction, as opposed to the wild-type controls. In spontaneously hypertensive rats there was marked PARP activation in the aorta, heart, and kidney. The endothelial dysfunction, the cardiovascular alterations and the activation of PARP were prevented by the angiotensin-converting enzyme inhibitor enalapril. We conclude that AII, via AII receptor subtype 1 activation and reactive oxygen and nitrogen species generation, triggers DNA breakage, which activates PARP in the vascular endothelium, leading to the development of endothelial dysfunction in hypertension.

Acetylcholine↗

PubMedDate not supplied

[An intron-free methyl jasmonate inducible geranylgeranyl diphosphate synthase gene from Taxus media and its functional identification in yeast].

Geranylgeranyl diphosphate synthase (GGPPS, EC: 2.5.1.29) catalyzes the biosynthesis of geranylgeranyl diphosphate (GGPP), which is a key precursor for diterpenes including Taxol, one of the most potent antitumor drugs. In order to investigate the role of GGPP synthase in taxol biosynthesis, we cloned, characterized and functionally expressed the GGPP synthase gene from Taxus media. A 3743-bp genomic sequence of T. media was isolated by genome walking strategy which contained an 1182-bp open reading frame (ORF) encoding a 393-amino acid polypeptide that showed high similarity to other plant GGPPSs. Subsequently the full-length cDNA of the GGPPS gene of T. media (designated TmGGPPS) was amplified by RACE. Bioinformatic analysis showed that TmGGPPS was an intron-free gene and its deduced polypeptide contained all the five conserved domains and functional aspartate-rich motifs of the prenyltransferases. By constructing the phylogenetic tree of plant GGPPSs, it was found that plant-derived GGPPSs could be divided into two classes, angiosperm and gymnosperm classes, which might have evolved in parallel from the same ancestor. To our knowledge this was the first report that the geranylgeranyl diphosphate synthase genes were free of intron and evolved in parallel between angiosperms and gymnosperms. The coding sequence of TmGGPPS was expressed in yeast mutant (SFNY368) lacking of GGPP synthase activity through functional complementation, and the transgenic yeast showed to have activity of GGPP synthase. This was also the first time to use SFNY368 to identify the function of plant-derived GGPPSs. Furthermore, investigation of the impact of methyl jasmonate (MeJA) on the expression of TmGGPPS revealed that MeJA-treated T. media cultured cells had much higher expression of TmGGPPS than untreated cells.

Acetates↗

PubMedDate not supplied

[Oxidase gene from sweetpotato].

Polyphenol oxidase is the enzyme responsible for enzymatic browning in sweetpotato that decreases the commercial value of sweetpotato products. Here we reported the cloning and characterization of a new cDNA encoding PPO from sweetpotato, designated as IbPPO (GeneBank accession number: AY822711). The full-length cDNA of IbPPO is 1984 bp with a 1767 bp open reading frame (ORF) encoding a 588 amino acid polypeptide with calculated molecular weight of 65.7 kDa and theoretical pI of 6.28. The coding sequence of IbPPO was also directly amplified from the genomic DNA of sweetpotato that demonstrated that IbPPO was an intron-free gene. The computational comparative analysis revealed that IbPPO showed homology to other PPOs of plant origin and contained a 50 amino acid plastidial transit peptides at its N-terminal and the two conserved CuA and CuB copper-binding motifs in the catalytic region of IbPPO. A highly conserved serine-rich motif was firstly found in the transit peptides of plant PPO enzymes. Then the homology-based structural modeling of IbPPO showed that IbPPO had the typical structure of PPO: the catalytic copper center was accommodated in a central four-helix bundle located in a hydrophobic pocket close to the surface. Finally, the results of the semi-quantitative RT-PCR analysis of IbPPO in different tissues demonstrated that IbPPO could express in all the organs of sweetpotato including: mature leaves, young leaves, the stems of mature leaves (petioles), the storage roots and the veins but at different levels. The highest-level expression of IbPPO was found in veins, followed by storage roots, young leaves and mature leaves; and the lowest-level expression of IbPPO was found in petioles. The present researches will facilitate the development of anti-brown sweetpotato by genetic engineering.

Amino Acid Motifs↗