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Biomedical subjects

Jun Zhong

Publications and source records attributed to Jun Zhong.

16 recordsLinked to original sources
PubMed2006

Dendritic mRNAs encode diversified functionalities in hippocampal pyramidal neurons.

BACKGROUND: Targeted transport of messenger RNA and local protein synthesis near the synapse are important for synaptic plasticity. In order to gain an overview of the composition of the dendritic mRNA pool, we dissected out stratum radiatum (dendritic lamina) from rat hippocampal CA1 region and compared its mRNA content with that of stratum pyramidale (cell body layer) using a set of cDNA microarrays. RNAs that have over-representation in the dendritic fraction were annotated and sorted into function groups. RESULTS: We have identified 154 dendritic mRNA candidates, which can be arranged into the categories of receptors and channels, signaling molecules, cytoskeleton and adhesion molecules, and factors that are involved in membrane trafficking, in protein synthesis, in posttranslational protein modification, and in protein degradation. Previously known dendritic mRNAs such as MAP2, calmodulin, and G protein gamma subunit were identified from our screening, as were mRNAs that encode proteins known to be important for synaptic plasticity and memory, such as spinophilin, Pumilio, eEF1A, and MHC class I molecules. Furthermore, mRNAs coding for ribosomal proteins were also found in dendrites. CONCLUSION: Our results suggest that neurons transport a variety of mRNAs to dendrites, not only those directly involved in modulating synaptic plasticity, but also others that play more common roles in cellular metabolism.

Animals↗
PubMed2006

Human fibrinogen adsorption onto single-walled carbon nanotube films.

The adsorption behavior of human fibrinogen (Hfg) on single-walled carbon nanotube (SWNT) films was investigated using scanning electron microscopy (SEM) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. It was shown in the SEM images that fibrinogen was adsorbed strongly on the surface of SWNT when the samples were incubated in the Hfg solutions for 10 min. The dependence of adsorption on the concentration of fibrinogen was also investigated and it was found that adsorption increased with increasing concentration. In order to further explore the adsorption of fibrinogen on SWNT surface, NEXAFS spectra were obtained at the N K-edge and the C K-edge. The results confirmed the conclusion regarding the dependence of adsorption on fibrinogen concentration. It is demonstrated that, due to its high sensitivity to the surface elements, NEXAFS spectroscopy is a powerful tool to investigate the adsorption of fibrinogen on SWNT films.

Adsorption↗
PubMed2006

ERK1/2 and p38 MAP kinase control MMP-2, MT1-MMP, and TIMP action and affect cell migration: a comparison between mesothelioma and mesothelial cells.

Pleural malignant mesothelioma is a locally aggressive tumor of mesothelial cell origin. In other tumor types high expression of matrix metalloproteinase (MMP)-2, together with membrane-type1-MMP (MT1-MMP), and low levels of the tissue inhibitor of MMP (TIMP)-2 have been correlated with aggressive tumor progression and low survival rates. Therefore, we compared the expression and activation of these three factors and their regulation by two mesothelioma associated growth factors, platelet-derived growth factor (PDGF)-BB, and transforming growth factor (TGF)-beta1 in six human mesothelioma and one mesothelial cell line. Polymerase chain reaction (PCR), immunoblotting, zymography, and small inhibitory RNAs (siRNA) were used to study gene expression, protein activation, and signal transduction. To proof the relevance of our in vitro data immunohistochemistry was performed in tissue sections. PDGF-BB induced, while TGF-beta1 inhibited cell proliferation. PDGF-BB was a chemoattractant for mesothelial cells, and its effect was increased in the presence of TGF-beta1. TGF-beta1 stimulated the de novo synthesis of pro-MMP-2 in both cell types. Pro-MMP-2 synthesis involved p38 MAP kinase. In cell culture and tissue sections only mesothelial cells expressed MT1-MMP. Migration of mesothelioma cells was dependent on the presence of MT1-MMP. Migration, but not proliferation of mesothelioma cells was inhibited by oleoyl-N-hydroxylamide, TIMP-2, and siRNA for MT1-MMP. Our data suggest that in mesothelioma cells the phosphorylation of p38 MAP kinase is deregulated and is involved in pro-MMP-2 expression. Mesothelioma progression depends on an interaction with mesothelial cells that provide MT1-MMP necessary to activate pro-MMP-2 to facilitate migration through an extracellular matrix (ECM) layer.

Becaplermin↗
PubMed2006

Analysis of the human protein interactome and comparison with yeast, worm and fly interaction datasets.

We present the first analysis of the human proteome with regard to interactions between proteins. We also compare the human interactome with the available interaction datasets from yeast (Saccharomyces cerevisiae), worm (Caenorhabditis elegans) and fly (Drosophila melanogaster). Of >70,000 binary interactions, only 42 were common to human, worm and fly, and only 16 were common to all four datasets. An additional 36 interactions were common to fly and worm but were not observed in humans, although a coimmunoprecipitation assay showed that 9 of the interactions do occur in humans. A re-examination of the connectivity of essential genes in yeast and humans indicated that the available data do not support the presumption that the number of interaction partners can accurately predict whether a gene is essential. Finally, we found that proteins encoded by genes mutated in inherited genetic disorders are likely to interact with proteins known to cause similar disorders, suggesting the existence of disease subnetworks. The human interaction map constructed from our analysis should facilitate an integrative systems biology approach to elucidating the cellular networks that contribute to health and disease states.

Animals↗
PubMed2005

Genome annotation of Anopheles gambiae using mass spectrometry-derived data.

BACKGROUND: A large number of animal and plant genomes have been completely sequenced over the last decade and are now publicly available. Although genomes can be rapidly sequenced, identifying protein-coding genes still remains a problematic task. Availability of protein sequence data allows direct confirmation of protein-coding genes. Mass spectrometry has recently emerged as a powerful tool for proteomic studies. Protein identification using mass spectrometry is usually carried out by searching against databases of known proteins or transcripts. This approach generally does not allow identification of proteins that have not yet been predicted or whose transcripts have not been identified. RESULTS: We searched 3,967 mass spectra from 16 LC-MS/MS runs of Anopheles gambiae salivary gland homogenates against the Anopheles gambiae genome database. This allowed us to validate 23 known transcripts and 50 novel transcripts. In addition, a novel gene was identified on the basis of peptides that matched a genomic region where no gene was known and no transcript had been predicted. The amino termini of proteins encoded by two predicted transcripts were confirmed based on N-terminally acetylated peptides sequenced by tandem mass spectrometry. Finally, six sequence polymorphisms could be annotated based on experimentally obtained peptide sequences. CONCLUSION: The peptide sequences from this study were mapped onto the genomic sequence using the distributed annotation system available at Ensembl and can be visualized in the context of all other existing annotations. The strategy described in this paper can be used to correct and confirm genome annotations and permit discovery of novel proteins in a high-throughput manner by mass spectrometry.

Animals↗
PubMed2005

A proteomic analysis of salivary glands of female Anopheles gambiae mosquito.

Understanding the development of the malaria parasite within the mosquito vector at the molecular level should provide novel targets for interrupting parasitic life cycle and subsequent transmission. Availability of the complete genomic sequence of the major African malaria vector, Anopheles gambiae, allows discovery of such targets through experimental as well as computational methods. In the female mosquito, the salivary gland tissue plays an important role in the maturation of the infective form of the malaria parasite. Therefore, we carried out a proteomic analysis of salivary glands from female An. gambiae mosquitoes. Salivary gland extracts were digested with trypsin using two complementary approaches and analyzed by LC-MS/MS. This led to identification of 69 unique proteins, 57 of which were novel. We carried out a functional annotation of all proteins identified in this study through a detailed bioinformatics analysis. Even though a number of cDNA and Edman degradation-based approaches to catalog transcripts and proteins from salivary glands of mosquitoes have been published previously, this is the first report describing the application of MS for characterization of the salivary gland proteome. Our approach should prove valuable for characterizing proteomes of parasites and vectors with sequenced genomes as well as those whose genomes are yet to be fully sequenced.

Animals↗
PubMed2004

Effect of silver nanoparticles on the electron transfer reactivity and the catalytic activity of myoglobin.

Silver nanoparticles (11+/-1.5 nm) could greatly enhance the electron-transfer reactivity of myoglobin (Mb) and its catalytic ability toward hydrogen peroxide (H2O2). Direct fast electron transfer between Mb and a pyrolytic graphite (PG) electrode was achieved, and a pair of well-defined, quasi-reversible redox peaks was obtained. The cathodic and anodic peaks were located at -329 and -281 mV, respectively. Meanwhile, the catalytic ability of the protein toward the reduction of H2O2 was also studied, and a H2O2 biosensor was subsequently fabricated. Its detection limit was 1.0 x 10(-6) M with a sensitivity of 0.0205 microA per microM of H2O2. The apparent Michaelis-Menten constant was calculated to be 1303 muM. Flocculation assay showed that the protein maintained plasmon layers surrounding the surface of silver nanoparticles and avoided silver-nanoparticle aggregation. On the other hand, UV-visible spectroscopy studies revealed that silver nanoparticles could induce a small change of the heme-group environment of the protein; this contributed to the enhancement of the electron-transfer reactivity and the catalytic activity.

Biosensing Techniques↗
PubMed2003

Direct electrochemical characterization of Vitreoscilla sp. hemoglobin entrapped in organic films.

The redox properties of a prokaryotic, Vitreoscilla sp. hemoglobin (VHb) in fuzzy organic films are studied with electrochemistry. This VHb exhibits irreversible electrochemical response at bare pyrolytic graphite (PG) electrode surfaces. However, upon being entrapped in organic films, the heterogeneous electron transfer rate of VHb will be sufficiently high to produce a quasi-reversible electrochemical response. The observation of electrocatalysis (reduction of O2) by hemes suggests that the protein can retain its biological activity under these conditions.

Bacterial Proteins↗
PubMed2003

[Treatment of acute ruptured aneurysm with Guglielmi detachable coil embolization].

OBJECTIVE: To investigate the curative effect of Guglielmi detachable coil (GDC) on acute ruptured intracranial aneurysms. METHODS: The clinical data of 34 patients with acute rupture of intracranial aneurysms treated with early GDC embolization within 6 days after the rupture, 6 being of grade I, 23 of grade II, 4 of grade III and 1 of grade IV according to Hunt-Hess grading, were analyzed retrospectively. Fourteen patients were treated within 3 days, and 20 patients were treated in the 4th to 6th days after the rupture. Two cases of wide-neck aneurysm were embolized with Medtronic AVE stent supported GDC. Angiography was used to observe the effects. RESULTS: Angiography showed complete occlusion in 28 cases and 90% occlusion in 4 cases. One aneurysm was ruptured during the procedure. The caudal tip of GDC protruded to the parent vessel in 2 cases. Two cases failed to be embolized due to severe cerebrovascular spasm. There were no mortality and complications. No re-rupture occurred in the follow-up. CONCLUSION: Less invasive and with less risk and complication, early GDC embolization is one of the ideal therapeutic methods to manage acute ruptured aneurysms.

Adult↗
PubMed2003

Evaluating brain tolerability to carotid artery occlusion.

An objective and practicable method to evaluate the brain tolerance to unilateral carotid artery occlusion was attempted. Ten consecutive cases were studied. Endovascular trial balloon occlusion of the unilateral carotid artery in conjunction with single-photon emission computed tomography (SPECT) as well as digital subtraction angiography (DSA) and clinical neurological evaluation was routinely performed for those patients who might undergo permanent occlusion of the internal (ICA) and/or common carotid artery (CCA). The result of SPECT was analyzed semi-quantitatively and compared with the baseline data as well as the data from contralateral side. The relative symmetry index (rS) of side-to-side radioactivity counts relevant to the baseline was calculated. One subject failed the balloon occlusion test (BOT), even though an angiographically adequate collateral circulation was observed. The rS of the patient was 74.5%. The remaining patients passed the 45-min BOT without any neurological deficiency induced. Their value of rS was 97.8% +/- 4.4%. Based the BOT results, the left ICA, CCA and external carotid artery were excised in one patient, CCA-ICA reconstructions after carotid occlusions were performed in three. The carotid arteries were saved in five. For one patient, the ICA was occluded spontaneously during the BOT. There were no neurological impairments developed after the surgery. With this BOT technique, clinically silent areas of decreased perfusion might be detected. We suggest it be a routine preparatory to carotid manipulations.

Adult↗
PubMed2003

Advances in ICP monitoring techniques.

With the advent of newer devices for measuring intracranial pressure (ICP) and cerebral metabolism, more alternatives continue to rise aiming to control ICP. This manuscript presents a proposed analysis of different ICP monitoring devices in order to make appropriate selection of them in our clinical setting including general and pediatric applications. A systematic review of the literature was made analyzing the technical advances in ICP monitoring. The recent in vitro and in vivo tests as well as mathematical/computer models were reviewed. Practical applications of principles were discussed and compared based on the mode of pressure transformation. A ventricular catheter connected to an external strain gauge transducer or catheter tip pressure transducer device is considered to be the most accurate method of monitoring ICP and enables therapeutic CSF drainage. The significant infections or hemorrhage associated with ICP devices causing patients morbidity are clinically rare and should not deter the decision to monitor ICP. Parenchymal catheter tip pressure transducer devices are advantageous when ventricular ICP cannot be obtained or if there is an obstruction in the fluid couple, though they have the potential for significant measurement differences and drift due to the inability to recalibrate. Subarachnoid or subdural fluid-coupled devices and epidural ICP devices are currently less accurate. With an increasing miniaturization of the transducers, fiberoptic systems have been developed, however, there is a problem of measurement accuracy during the period of patient monitoring and external calibration should be performed frequently to ensure constant accuracy. Ventriculostomies continue to have a pivotal role in ICP control. With a rational understanding of the applications and limitations of the different ICP monitoring devices, the outcome for critically ill neurological patients is optimized.

Animals↗
PubMed2003

Omental transposition to the brain as a surgical method for treating Alzheimer's disease.

The purpose of this study was to learn the effect of omental transposition to the brain of patients who exhibited the most serious effects of long-standing Alzheimer's disease. Ten patients who had extremely low Mini Mental-State Examination scores of 2-14 underwent placement of their elongated pedicled omentum onto their left parietal-temporal cerebral cortex. Patients underwent pre- and post-operative MRI and SPECT scans in addition to long-term neurological and neuropsychological testing. All were followed up to one year. In spite of the patients' severe cognitive and functional disability, several of the patients demonstrated subjective and objective improvement, especially in terms of their functional status.

Activities of Daily Living↗
PubMed2003

Brain retraction injury.

This paper reviews the literature of the brain retraction injury during the last century. The review focused on the instrument characteristic as well as the physiopathological and histopathological damage of the brain induced by brain retraction. It was found that lesions were induced by cerebral ischemia. We conclude that a better monitoring system needs to be developed to avoid brain injury.

Animals↗
PubMed2003

Sensing phenothiazine drugs at a gold electrode co-modified with DNA and gold nanoparticles.

DNA and gold nanoparticles are co-immobilized at a gold electrode through elaborate self-assembly processes. This configuration has proven to be useful as a sensor for phenothiazine drugs, taking advantage of the well-known, relatively large surface area of gold nanoparticles and the strong intercalation between dsDNA and phenothiazine drugs. This modified electrode has demonstrated good sensitivity and stability towards the oxidation of two model phenothiazine drugs: promethazine and chlorpromazine. A linear dependence between the concentration of phenothiazine drugs and the peak current is observed, with a concentration range of 2.0 x 10(-5)-1.6 x 10(-4) M and 1.0 x 10(-5)-1.2 x 10(-4) M, and a detection limit of 1.0 x 10(-5) M and 7.0 x 10(-6) M, for promethazine and chlorpromazine, respectively.

Animals↗
PubMedDate not supplied

Phosphoproteome analysis of HeLa cells using stable isotope labeling with amino acids in cell culture (SILAC).

Identification of phosphorylated proteins remains a difficult task despite technological advances in protein purification methods and mass spectrometry. Here, we report identification of tyrosine-phosphorylated proteins by coupling stable isotope labeling with amino acids in cell culture (SILAC) to mass spectrometry. We labeled HeLa cells with stable isotopes of tyrosine, or, a combination of arginine and lysine to identify tyrosine phosphorylated proteins. This allowed identification of 118 proteins, of which only 45 proteins were previously described as tyrosine-phosphorylated proteins. A total of 42 in vivo tyrosine phosphorylation sites were mapped, including 34 novel ones. We validated the phosphorylation status of a subset of novel proteins including cytoskeleton associated protein 1, breast cancer anti-estrogen resistance 3, chromosome 3 open reading frame 6, WW binding protein 2, Nice-4 and RNA binding motif protein 4. Our strategy can be used to identify potential kinase substrates without prior knowledge of the signaling pathways and can also be applied to profiling to specific kinases in cells. Because of its sensitivity and general applicability, our approach will be useful for investigating signaling pathways in a global fashion and for using phosphoproteomics for functional annotation of genomes.

Amino Acid Sequence↗