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Biomedical subjects

J Deng

Publications and source records attributed to J Deng.

At least 91 records · Page 5Linked to original sources
PubMed1999

A novel pineal night-specific ATPase encoded by the Wilson disease gene.

We have identified a pineal night-specific ATPase (PINA), a novel splice variant of the ATP7B gene disrupted in Wilson disease (WD). PINA expression exhibits a dramatic diurnal rhythm in both pineal gland and retina with 100-fold greater expression at night than at day. PINA is expressed in pinealocytes and a subset of photoreceptors in adult rats and is transiently expressed in the retinal pigment epithelium and the ciliary body during retinal development. Nocturnal pineal expression of PINA is under the control of a suprachiasmatic nucleus clock mediated by superior cervical ganglion innervation of the pineal. In vitro, PINA expression in pineal cells can be stimulated by agents activating the cAMP signal transduction pathway. PINA is able to restore copper transport activity in Saccharomyces cerevisiae deficient in the homologous copper-transporting ATPase CCC2, suggesting that this protein may function as a copper transporter in rat pinealocytes. These studies suggest a potential role of rhythmic copper metabolism in pineal and/or retina circadian function.

Adenosine Triphosphatases↗
PubMed1999

Fast reversible electron transfer for photosynthetic reaction center from wild type Rhodobacter sphaeroides re-constituted in polycation sandwiched monolayer film.

Direct reversible electron transfer for photosynthetic reaction center from wild type Rhodobacter sphaeroides re-constituted in polycation sandwiched monolayer film was observed in this work. The redox potential E0' = 0.46 V vs. NHE for first primary donor redox couple P/P+ was accurately measured from reversible CV or SWV peaks, which were quite close to those obtained from optic redox titration method. Reaction center (RC) in film was found re-constituted in such an ordered way that the orientation of RC favored the electron transfer in film. Thus, the protein electroactivity seems to be turned on in this artificial biomimic thin film. Furthermore, RC in the film features a photo-induced redox-peak fluctuation, suggesting an intact and functional state for RC in such film. Redox peaks were also found dependent of pH, implying a proton-coupled electron transfer occurring in film. Charge recombination was observed accompanied with change of electrochemical driving force. Electrochemical model assuming several classes of electroactive sites in the films on the electrode with a dispersion of standard potentials successfully fits SWV experimental data at different pulse height and frequency.

Electrochemistry↗
PubMed1999

Interactions of Alzheimer amyloid-beta peptides with glycosaminoglycans effects on fibril nucleation and growth.

Proteoglycans and their constituent glycosaminoglycans are associated with all amyloid deposits and may be involved in the amyloidogenic pathway. In Alzheimer's disease, plaques are composed of the amyloid-beta peptide and are associated with at least four different proteoglycans. Using CD spectroscopy, fluorescence spectroscopy and electron microscopy, we examined glycosaminoglycan interaction with the amyloid-beta peptides 1-40 (Abeta40) and 1-42 (Abeta42) to determine the effects on peptide conformation and fibril formation. Monomeric amyloid-beta peptides in trifluoroethanol, when diluted in aqueous buffer, undergo a slow random to amyloidogenic beta sheet transition. In the presence of heparin, heparan sulfate, keratan sulfate or chondroitin sulfates, this transition was accelerated with Abeta42 rapidly adopting a beta-sheet conformation. This was accompanied by the appearance of well-defined amyloid fibrils indicating an enhanced nucleation of Abeta42. Incubation of preformed Abeta42 fibrils with glycosaminoglycans resulted in extensive lateral aggregation and precipitation of the fibrils. The glycosaminoglycans differed in their relative activities with the chondroitin sulfates producing the most pronounced effects. The less amyloidogenic Abeta40 isoform did not show an immediate structural transition that was dependent upon the shielding effect by the phosphate counter ion. Removal or substitution of phosphate resulted in similar glycosaminoglycan-induced conformational and aggregation changes. These findings clearly demonstrate that glycosaminoglycans act at the earliest stage of fibril formation, namely amyloid-beta nucleation, and are not simply involved in the lateral aggregation of preformed fibrils or nonspecific adhesion to plaques. The identification of a structure-activity relationship between amyloid-beta and the different glycosaminoglycans, as well as the condition dependence for glycosaminoglycan binding, are important for the successful development and evaluation of glycosaminoglycan-specific therapeutic interventions.

Alzheimer Disease↗
PubMed1999

Hippocampal Cajal-Retzius cells project to the entorhinal cortex: retrograde tracing and intracellular labelling studies.

Cajal-Retzius (CR) cells are characteristic horizontally orientated, early-generated transient neurons in the marginal zones of the neocortex and hippocampus that synthesize the extracellular matrix protein reelin. They have been implicated in the pathfinding of entorhino-hippocampal axons, but their role in this process remained unclear. Here we have studied the axonal projection of hippocampal CR cells. Following injection of the carbocyanine dye DiI into the entorhinal cortex of aldehyde-fixed rat embryos and young postnatal rats, neurons in the outer molecular layer of the dentate gyrus and stratum lacunosum-moleculare of the hippocampus proper with morphological characteristics of CR cells were retrogradely labelled. In a time course analysis, the first retrogradely labelled CR cells were observed on embryonic day 17. This projection of hippocampal CR cells to the entorhinal cortex was confirmed by retrograde tracing with Fast Blue in new-born rats and by intracellular biocytin filling of CR cells in acute slices from young postnatal rat hippocampus/entorhinal cortex and in entorhino-hippocampal slice cocultures using infrared videomicroscopy in combination with the patch-clamp technique. In double-labelling experiments CR cells were identified by their immunocytochemical staining for reelin or calretinin, and their interaction with entorhino-hippocampal axons labelled by anterograde tracers was analysed. Future studies need to investigate whether this early transient projection of hippocampal CR cells to the entorhinal cortex is used as a template by the entorhinal axons growing to their target layers in the hippocampus.

Amidines↗
PubMed1999

Three-dimensional morphometry in ultrasound.

The clinical use of three-dimensional (3D) ultrasound has rapidly spread to many specialities over the last ten years. The reason is easy to see, namely that single two-dimensional (2D) scans are often difficult to interpret and the mental correlation of multiple 2D scans to form a 3D image of anatomical morphology is taxing and uncertain. The rapid development of techniques for the realtime tracking of the spatial position and orientation of ultrasound probes and the development of computer graphics techniques for the presentation of anatomical images have made 3D ultrasound a realistic diagnostic tool. The authors describe the range of methods of data acquisition and display and provide illustrations of some current clinical applications.

Adult↗
PubMed1999

[Construction and expression of HLA-DRalpha, DRB1*0401 transgenic mice model].

OBJECTIVE: To construct transgenic mice model on DR alpha and DRB1*0401 of human MHC-II molecules. METHODS: By microinjection techniques on germ nucleus of zygotes, DRalpha and DRB1*0401 genes were injected into zygotes of C57BL/6 x DBA/1 hybrid mice and transplanted into the oviducts of pseudopregnancy female mice. The integration and expression of exogenous genes in offspring were detected by PCR, Southern blot and Northern blot, RT-PCR analysis. RESULTS: There were 5 founders of all injected mice, which had steadily inherited to the fifth generation. It was found that 95 mice were positive by PCR and 68 mice were integrated exogenous gene by Southern blot analysis. DRalpha and DRB1*0401 genes were expressed on spleen and kidney of transgenic mice. CONCLUSION: This experiment on the construction of DRalpha and DRB1*0401 transgenic mice model is a success.

Animals↗
PubMed1999

Construction of La-tPA vector and expression in the mammary gland of transgenic mice.

Expression vectors of long acting human tissue plasminogen activator (La-tPa) in the mammary gland was constructed using the promoters of sheep beta-lactoglobulin gene (BLG, 5 kb) containing the first and the second introns obtained by PCR. Transgenic mice were established by microinjection. 540 fertilized eggs were injected and 6 transgenic mice were screened out from the offspring by PCR and Southern Blot analysis. The foreign gene integrating rate was 32%. The expression of La-tPA in mammary glands of transgenic mice was confirmed by milk assay and Northern blot analysis. Expression level of La-tPA reached 6 ug/ml in milk of transgenic mice.

Animals↗
PubMed1999

[A scanning method for detecting colorectal tumors].

OBJECTIVE: To develop a method for survey of colorectal tumors. METHODS: Mucus obtained by digital rectal examination was smeared on a slice to react with peanut agglutinin labeled by Horseradish-peroxidase. RESULTS: Brown color was noted in positive reaction. In detecting colorectal tumors, the sensitivity and specificity of the method was 88.2% and 92.5% respectively. CONCLUSION: The method is effective in detecting colorectal tumors in humans.

Adult↗
PubMed1999

[Improvements on radical neck dissection].

OBJECTIVE: To improve the surgery of radical neck dissection for a better curative effect. METHOD: Some improvements on incision, path to exploration and manipulation of operation were made in 65 patients with head and neck tumors while radical neck dissection were done. RESULT: The average surgical time was 110 minutes and the average amount of bleeding was 120 ml in the patients when radical neck dissection had been completed. The complications decreased to 1.54%. The surviual rates of 2 and 3 years are 86.2% (56/65) and 81.6 (31/38) respectively. CONCLUSION: With these improvements on radical neck dissection, the curative effect in the near future is improved.

Adolescent↗
PubMed1999

[Cloning and sequencing of cDNA from G protein gene of subgroup B respiratory syncytial virus strain isolated in China].

The nucleotide sequence of the G protein gene of respiratory syncytial virus (RSV) CC169 strain isolated from China that has been identified as subgroup B with monoclonal antibodies, was determined from cDNA that had been amplified by RT-PCR and cloned into pTZ18R plasmid vector. The homology of nucleotide was 94% as compared with G protein cDNA of a RSV prototype strain (CH18537). Deduced amino acid identity of G protein was 89.4%. The amino acid changes were only in the extracellular part of the protein where there were two extensive divergent domains with a highly conserved region in between; whereas the cytoplasmic and transmembrane domains were conserved. This study demonstrates the sequence diversity of the G protein of subgroup B RSV between a Chinese isolate and the prototype strain CH18537.

Amino Acid Sequence↗
PubMed1999

Elevated vascular endothelial growth factor levels in the vitreous of patients with proliferative diabetic retinopathy.

OBJECTIVE: To detect the levels of vascular endothelial growth factor (VEGF) in the vitreous of patients with proliferative diabetic retinopathy (PDR) and to investigate the possible role of VEGF in the development of neovascularization in PDR. METHODS: Undiluted vitreous samples and fasting venous blood samples were obtained from 27 patients with PDR and 14 subjects with idiopathic macular hole who underwent pars plana vitrectomy. The concentration of VEGF was determined by quantitative enzyme-linked immunosorbent assay (ELISA). RESULTS: The level of vitreous VEGF in patients with PDR (median 0.41 ng/ml, range 0.09-11.56 ng/ml) was significantly elevated when compared with that in control subjects (median 0.017 ng/ml, range 0.008-0.04 ng/ml) (P < 0.001). The median of PDR patients' serum VEGF concentration was 0.19 ng/ml (0.090.46 ng/ml) which was far lower than vitreous VEGF concentration (P < 0.05). Vitreous VEGF concentration was higher in PDR patients with retinal detachment than that in patient without retinal detachment (P < 0.05). CONCLUSIONS: Vitreous levels of VEGF were remarkably elevated in eyes with PDR, and they were not influenced by its serum concentrations. VEGF played an important role in neovascularization of PDR.

Adult↗
PubMed1998

Viscoelastic flow in the lower crust after the 1992 landers, california, earthquake

Space geodesy showed that broad-scale postseismic deformation occurred after the 1992 Landers earthquake. Three-dimensional modeling shows that afterslip can only explain one horizontal component of the postseismic deformation, whereas viscoelastic flow can explain the horizontal and near-vertical displacements. The viscosity of a weak, about 10-km-thick layer, in the lower crust beneath the rupture zone that controls the rebound is about 10(18) pascal seconds. The viscoelastic behavior of the lower crust may help to explain the extensional structures observed in the Basin and Range province and it may be used for the analysis of earthquake hazard.

Journal Article↗
PubMed1998

Adenovirus 5 E1A-mediated tumor suppression associated with E1A-mediated apoptosis in vivo.

Disruption of apoptotic pathways is a major factor in the multistep process of tumorigenesis, whereas induction of apoptosis can be important for tumor suppression and cancer therapy. The adenovirus type 5 E1A gene provides a useful tool to study the function of tumor suppression and apoptosis. E1A has been shown to induce apoptosis in different systems in vitro. However, this activity has not been well characterized in vivo. Therefore, the effect of this activity and the link to the in vivo biological function are not clear. To answer these questions, we introduced E1A into murine melanoma cells and characterized the biological features both in vitro and in vivo. Expression of the E1A gene does not affect the proliferation rate of tumor cells in vitro, but inhibits tumor growth in vivo. The in vitro analysis indicated that the E1A-expressing tumor cells are sensitive to serum depletion-induced apoptosis. Importantly, E1A-mediated apoptosis was also identified in vivo, suggesting this activity contributed to the tumor suppressive function. The in vivo apoptotic pattern was unique: most of the apoptotic cells were around the periphery of the tumors, implicating the interaction of these cells with stress stimuli in vivo. In addition, E1A also rendered the tumor cells susceptible to the cytotoxicity of other anticancer agents, a feature useful for improving the efficacy of cancer therapy. The results provide a functional link between in vitro activity and in vivo effects.

Adenovirus E1A Proteins↗
PubMed1998

Multiple isoforms of DNA methyltransferase are encoded by the vertebrate cytosine DNA methyltransferase gene.

This manuscript tests the hypothesis that multiple forms of cytosine-DNA methyltransferase (MeTase) are expressed in vertebrates in vivo. Vertebrate genomes are distinguished by tissue- and gene-specific DNA methylation patterns. Specific methylation patterns are believed to encode epigenetic information. In distinction from the remarkable diversity of DNA methylation patterns, only one functional DNA MeTase cDNA has been identified to date in different vertebrate organisms. Using reverse transcription-polymerase chain reaction and RNase protection analyses, we show that the methyltransferase domain of the rat DNA MeTase is alternatively spliced in vivo, generating different in-frame variants of DNA MeTase in specific tissues. This process is developmentally regulated and is induced in PC12 cells by a known inducer of neuronal differentiation, nerve growth factor. The data presented here point toward a new mechanism for generating diversity of DNA MeTases and possibly diverse DNA methylation patterns.

Alternative Splicing↗
PubMed1998

Involvement of Ras in Bruton's tyrosine kinase-mediated JNK activation.

Defects in Bruton's tyrosine kinase (Btk) result in B cell immunodeficiencies in humans and mice. Recent studies showed that Btk is required for maximal activation of JNK, a family of stress-activated protein kinases, induced by several extracellular stimuli including interleukin (IL)-3. On the other hand, IL-3-induced JNK activation is dependent on Ras. In the present study we have investigated whether Ras is involved in Btk-mediated JNK activation in BaF3 mouse pro-B cells. Overexpression of wild-type Btk protein in these cells enhanced JNK activation upon IL-3 stimulation, whereas expression of kinase-dead Btk partially suppressed JNK activation. Induced expression of the dominant negative Ras(N17) in the cells overexpressing wild-type Btk suppressed JNK activation. Importantly, overexpression of Btk enhanced the level of the GTP-bound, active form of Ras in response to IL-3 stimulation. Btk overexpression also increased the Shc-Grb2 association induced by IL-3 stimulation. Expression of either N17Ras or V12Ras did not impose any effects on Btk kinase activity. These data collectively indicate that Ras plays a role of an intermediary signaling protein in Btk-mediated JNK activation induced by the IL-3 signaling pathway.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Selective uptake of low density lipoprotein-cholesteryl ester is enhanced by inducible apolipoprotein E expression in cultured mouse adrenocortical cells.

Apolipoprotein (apo) E is expressed at high levels by steroidogenic cells of the adrenal gland, ovary, and testis. The cell surface location of apoE in adrenocortical cells suggests that apoE may facilitate the uptake of lipoprotein cholesterol by either the endocytic or the selective uptake pathways, or both. To examine these possibilities, the human apoE gene was expressed in murine Y1 adrenocortical cells under control of an inducible tetracycline-regulated promoter. The results show that induction of apoE yielded a 2-2.5-fold increase in the uptake of low density lipoprotein-cholesteryl ester (LDL-CE) but had little effect on high density lipoprotein-CE uptake. Analysis of lipoprotein uptake pathways showed that apoE increased LDL-CE uptake by both endocytic and selective uptake pathways. In terms of cholesterol delivery to the adrenal cell, the apoE-mediated enhancement of LDL-CE selective uptake was quantitatively more important. Furthermore, the predominant effect of apoE expression was on the low affinity component of LDL-CE selective uptake. LDL particles incubated with apoE-expressing cells contained 0.92 +/- 0.11 apoE molecules/apoB after gel filtration chromatography, indicating stable complex formation between apoE and LDL. ApoE expression by Y1 cells was necessary for enhanced LDL-CE selective uptake. This result may indicate an interaction between apoE-containing LDL and cell surface apoE. These data suggest that apoE produced locally by steroidogenic cells facilitates cholesterol acquisition by the LDL selective uptake pathway.

Adrenal Cortex↗
PubMed1998

A small proline-rich protein, spr1: specific marker for squamous lung carcinoma.

We have identified a small proline-rich protein, spr1, which is a sensitive and specific marker for distinguishing squamous cancer from the other cell types of lung carcinoma. A rabbit antiserum against a 15-amino-acid peptide of the C-terminus of spr1 was prepared. The specificity of this antiserum was demonstrated in normal squamous tissues by Western blotting and immunohistochemical analysis. Expression of spr1 in 63 cases of formalin-fixed and paraffin-embedded human bronchogenic carcinoma was studied by immunohistochemical staining. For these 63 cases of bronchogenic carcinoma previously diagnosed by hematoxylin/eosin (H/E) staining, the number of spr1-positive cases/total number of H/E cases of each cell type of lung cancer were as follows: 20/20 of squamous carcinoma, 2/18 of adenocarcinoma, 4/14 of large-cell carcinoma, and 0/11 of small-cell lung carcinoma. Squamous differentiation evidenced by spr1 expression was substantiated by the presence of squamous features observed under transmission electron microscopy (TEM). We conclude that spr1 is a sensitive and specific marker for squamous bronchogenic carcinoma.

Biomarkers, Tumor↗