Biomedical subjects

J Zhou

Publications and source records attributed to J Zhou.

At least 361 records · Page 20Linked to original sources

PubMed2000

[Result of orthokeratology for treatment of young people with myopia].

PURPOSE: To evaluate the effectiveness of orthokeratology (Ortho-K) for treatment of myopia in youngths. METHODS: 110 eyes of 56 young peoples with myopia received Ortho-K were studied. The patients were divided into 3 groups according to preoperative diopters. No. I: -1.00(-)-3.00 D, No. II: -3.25(-)-6.00 D, NO. III: -6.25(-)-7.50 D. The uncorrected visual acuities, residual diopters and corneal refractive powers at various time of three months after the operation were statistically analyzed and compared with that of preoperation. Correlation analysis and linear regression analysis were performed between the corneal refractive reduction (X) and clinical refractive reduction (Y) after 3 months of the operation. RESULTS: In 110 eyes, the uncorrected visual acuities in the first day, first week, first month, second month and third month after operation were significantly improved than that of the preoperation (P < 0.01). The mean residual diopters were significantly reduced than that of preoperation (P < 0.01). The mean refractive powers of cornea were significantly decreased than that of the preoperative (P < 0.01). There was significant correlation between the corneal refractive reduction and clinical refractive reduction. (r = 0.3181, P < 0.001). CONCLUSION: Orthokeratology is a safe and effective therapeutic method for treatment of myopia in youngths. The long term effect of Orthokeratology need further observation.

Adolescent↗

PubMed2000

[Apoptosis of chondrocytes in cartilage].

OBJECTIVE: To observe apoptosis of chondrocytes in cartilage and arthritis. METHODS: Apoptosis was detected by light and electron microscope and DNA electrophoresis, while [Ca2+]i was detected by confocal laser scanning microscope. RESULTS: Cartilage cells from osteoarthritis (OA) and rheumatoid arthritis (RA) could be seen to undergo normal differentiation after cultured for 3 days under light or electron microscope, while some chondrocytes directly isolated without culturing could give early changes of apoptosis, and normal chondrocytes in vitro after treatment with IL-1, TNF-alpha also underwent apoptosis. IL-1, TNF-alpha could induce increase of [Ca2+]i in chondrocytes. CONCLUSIONS: Our data showed that apoptosis might present in the normal cartilage as well as in OA and RA cells. IL-1, TNF-alpha could induce apoptosis of chondrocytes and [Ca2+]i increase during apoptosis.

Animals↗

PubMed2000

[Erythroid differentiation denucleation factor: a family of erythroid regulators for mammalian erythroid terminal differentiation/tumor suppression and the cloning of their related genes].

The role of regulation of erythroid differentiation denucleation factor(EDDF) on mammalian erythroid differentiation and myeloma cell malignancy as well as cloning of their stage related genes were serially studied. Through a series of cybrid and hybridization experiments between mammalian erythroid cells and erythroleukemia or non-erythroid myeloma cells, we have demonstrated a novel family of erythroid regulators(EDDFs) in the mammalian differentiating erythroblasts which with an active peak occurred concomitantly with marked decreases in DNA, RNA and the nuclear anchoring vimentin-IF, but increased in hemoglobin synthesis in cytoplasm prior to the denucleation process during terminal differentiation. The results of cell fusion experiments verified that the supplement of regulators(EDDFs) was critical to the recovery of the originally lost features of terminal differentiation and the reversion of malignant phenotype of tumor cells. Here we showed that the erythroid regulator family EDDFs were essential regulators for the sequential expression of stage related genes of erythroid terminal differentiation, and for the redifferentiation of tumor cells to express the originally inactive globe genes, repressed the oncogenes, and vimentin-IF system, thus initiated nuclear condensation and denucleation. The EDDF gene family consisted of MEDDF, HEDDF-1, HEDRF-1, HEDRF-2 and HCNBP-1 were cloned. All were novel cDNA sequences that have been searched and registered in GenBank. They expressed varying in a stage specific manner, and acted on corresponding genes of terminal differentiation.

Activins↗

PubMed2000

[Determination of palladium by ion exchange resin phase spectrophotometry].

A new method for the determination of palladium by ion exchange resin phase spectrophotometry has been established. It is based on the fixation of palladium as 1-(5-bromo-2-phridylazo)-2-naphthol-6-sulphonic acid (5-Br-PAN-S) compelled on a anion-exchange resin. The resin phase absorbances at 690 and 800 nm are measured directly and the linear range of 0-20 micrograms for palladium. The method has been applied to the determination of palladium in water samples and catalysts with satisfactory results.

Ion Exchange Resins↗

PubMed2000

[The noise-filtering of chemiluminescence spectra with wavelet multiresolution analysis].

In this paper, the wavelet multiresolution signal decomposition was successfully applied to the filtering of high-frequency noise in chemiluminescence spectra. The spectra signal-to-noise ratio was greatly improved while the noise was suppressed effectively. The effect of wavelet basis and time of decomposition are also discussed. It is shown that the wavelet analyses have many advantages in processing of discrete signals.

Algorithms↗

PubMed2000

[Photoluminescence characteristics of mixed aggregates in Langmuir-Blodgett multilayers].

Effects of the mixed aggregates of different active molecules and UV illumination on photoluminescence(PL) spectra of Langmuir-Blodgett multilayers were investigated. The strong interaction between hemicyanine and stilbazolium salt molecules in the mixed films caused a blue or red shift of the fluorescence band with respect to that of interleaving hemicyanine or stilbazolium salt/arachidic acid multilayers. UV illumination would dissociate the aggregates even more destroy the molecular structure, leading to a significant reduction of fluorescence intensity.

English Abstract↗

PubMed2000

[Experimental study of Ti-75(AlMoZrTi alloy) dental implants in dog mandible].

OBJECTIVE: The purpose of this study was to investigate the biocompatibility of Ti-75(AlMoZrTi Alloy) dental implants. METHODS: Four 6.5 to 16 kg dogs were used,after mandibular cuspids and premolar extraction, 16 implants were placed and left for six or twelve months. All of the dental implants were made of Ti-75 (AlMoZrTi Alloy) and they were manufactured in two types-nonsubmerged and submerged threaded implants. RESULTS: The survival rate of the implants was 100% (submerged implants) and 91.7% (nonsubmerged implants). Histologically,all survival implants showed some degree of intimate bone to implant contact, but one of the nonsubmerged implants showed periimplantitis. No implants were observed to be mobile. The periotest values of the dental implants were near the periotest values of the nature teeth. CONCLUSION: This study demonstrated Ti-75 is a biocompatible material and periotest is worthy of detection of osseointegration.

English Abstract↗

PubMed1999

Nerve growth factor signaling in caveolae-like domains at the plasma membrane.

Nerve growth factor (NGF) binding to its receptors TrkA and p75(NTR) enhances the survival, differentiation, and maintenance of neurons. Recent studies have suggested that NGF receptor activation may occur in caveolae or caveolae-like membranes (CLM). This is an intriguing possibility because caveolae have been shown to contain many of the signaling intermediates in the TrkA signaling cascade. To examine the membrane localization of TrkA and p75(NTR), we isolated caveolae from 3T3-TrkA-p75 cells and CLM from PC12 cells. Immunoblot analysis showed that TrkA and p75(NTR) were enriched about 13- and 25-fold, respectively, in caveolae and CLM. Binding and cross-linking studies demonstrated that the NGF binding to both TrkA and p75(NTR) was considerably enriched in CLM and that about 90% of high affinity binding to TrkA was present in CLM. When PC12 cells were treated with NGF, virtually all activated (i.e. tyrosine phosphorylated) TrkA was found in the CLM. Remarkably, in NGF-treated cells, it was only in CLM that activated TrkA was coimmunoprecipitated with phosphorylated Shc and PLCgamma. These results document a signaling role for TrkA in CLM and suggest that both TrkA and p75(NTR) signaling are initiated from these membranes.

Animals↗

PubMed1999

A novel cis-regulatory element, the PTS, mediates an anti-insulator activity in the Drosophila embryo.

The Abd-B Hox gene contains an extended 3' cis-regulatory region that is subdivided into a series of separate lab domains. The lab-7 domain activates Abd-B in parasegment 12 (ps12), whereas lab-8 controls expression in ps13. iab-7 is flanked by two insulators, Fab-7 and Fab-8, which are thought to prevent regulatory factors, such as Polycomb silencers, from influencing neighboring iab domains. This organization poses a potential paradox, since insulator DNAs can work in a dominant fashion to block enhancer-promoter interactions over long distances. Here, we present evidence for a novel cis-regulatory sequence located within lab-7, the promoter targeting sequence (PTS), which permits distal enhancers to overcome the blocking effects of Fab-8 and the heterologous su(Hw) insulator. We propose that the PTS converts dominant, long-range insulators into local regulatory elements that separate neighboring lab domains.

Animals↗

PubMed1999

Molecular cloning of six novel Krüppel-like zinc finger genes from hematopoietic cells and identification of a novel transregulatory domain KRNB.

To clone zinc finger genes expressed in hematopoietic system, we designed primers based on conserved Cys(2)/His(2) zinc finger sequences to amplify corresponding domains from mRNA of normal bone marrow and leukemia cell line NB4. DNA fragments of novel zinc finger genes were chosen and used as probe pool to screen cDNA libraries or subject to rapid amplification of cDNA ends in order to obtain full-length cDNA. Six cDNAs including whole open reading frame of zinc finger proteins, named as ZNF191, ZNF253 (BMZF-1), ZNF255 (BMZF-2), ZNF256 (BMZF-3), ZNF257 (BMZF-4), and ZNF254 (BMZF-5) were obtained. All six belong to the Krüppel-like zinc finger gene family, and typical transcriptional regulatory motifs exist in the N-terminal moiety, such as the SCAN box in ZNF191, and the KRAB domains in ZNF253, ZNF254, ZNF256, and ZNF257. A previously undefined sequence nominated as Krüppel-related novel box, which may represent a new transregulatory motif, was revealed at the N terminus of ZNF255. The transregulatory function of non-zinc finger regions of ZNF191, ZNF253, and ZNF255 were addressed in yeast and mammalian cells. The results indicated that ZNF255 might be a conditional transactivator, whereas ZNF253 and ZNF191 displayed a suppressive effect on the transcription in yeast and/or mammalian systems.

Amino Acid Sequence↗

PubMed1999

Iron reduction by psychrotrophic enrichment cultures.

Psychrotrophic (<20 degrees C) enrichment cultures from deep Pacific marine sediments and Alaskan tundra permafrost reduced ferric iron when using organic acids or H(2) as electron donors. The representative culture W3-7 from the Pacific sediments grew fastest at 10 degrees C, which was 5-fold faster than at 25 degrees C and more than 40-fold faster than at 4 degrees C. Fe(III) reduction was also the fastest at 10 degrees C, which was 2-fold faster than at 25 degrees C and 12-fold faster than at 4 degrees C. Overall, about 80% of the enrichment cultures exhibited microbial Fe(III) reduction under psychrotrophic conditions. These results indicated that microbial iron reduction is likely widespread in cold natural environments and may play important roles in cycling of iron and organic matter over geological times.

Journal Article↗

PubMed1999

Differential display and cloning of the hippocampal gene mRNas in senescence accelerated mouse.

Identification of genes that are specifically expressed in the hippocampus of senescence accelerated mouse (SAM) is important for understanding the molecular basis of the pathological changes in the brain and of the deterioration of learning and memory in SAM-prone/8 (SAMP8), a substrain of SAM. The differential display technique was applied to compare mRNAs expression between SAMP8 and SAM-resistance 1 (SAMR1), another substrain of SAM. Complementary DNA fragments corresponding to several apparently differentially expressed mRNAs were recovered and sequenced. Six differentially expressed cDNA bands were identified. Sequence analyses demonstrated that W4 and W5 cDNA fragments corresponded to unknown genes. W1 and W6 showed 66.1 and 62.3% homology to rat GTP-exchange protein (eIF-2B) and rat phospholipase D, respectively, while W2 and W3 showed 89.2 and 90.8% homology to human bullous pemphigoid antigen and human glucogen debranching enzyme isoform 1/2/3/4/6, respectively. The results suggested that these genes are closely related to the malfunction of the brain in SAM.

Aging↗

PubMed1999

The role of DOC-2/DAB2 protein phosphorylation in the inhibition of AP-1 activity. An underlying mechanism of its tumor-suppressive function in prostate cancer.

DOC-2/DAB2, a novel phosphoprotein with signal-transducing capability, inhibits human prostatic cancer cells (Tseng, C.-P., Ely, B. D., Li, Y., Pong, R.-C., and Hsieh, J.-T. (1998) Endocrinology 139, 3542-3553). However, its mechanism of action is not understood completely. This study delineates the functional significance of DOC-2/DAB2 protein phosphorylation and demonstrates that in vivo activation of protein kinase C (PKC) by 12-O-tetradecanoylphorbol-13-acetate (TPA) induces DOC-2/DAB2 phosphorylation, including a serine residue at position 24. Mutation of Ser(24) to Ala reduced DOC-2/DAB2 phosphorylation by PKC. Using a synthetic Ser(24) peptide (APS(24)KKEKKKGSEKTD) or recombinant DOC-2/DAB2 as substrates, PKCbetaII, PKCgamma, and PKCdelta (but not casein kinase II) directly phosphorylated Ser(24) in vitro. This indicates that DOC-2/DAB2 is a PKC-specific substrate. Since expression of wild-type DOC-2/DAB2, but not the S24A mutant, inhibited TPA-induced AP-1 activity in prostatic epithelial cells, phosphorylation of Ser(24) appears to play a critical role in modulating TPA-induced AP-1 activity. Taken together, these data suggest that PKC-regulated phosphorylation of DOC-2/DAB2 protein may help its growth inhibitory function.

Adaptor Proteins, Signal Transducing↗

PubMed1999

Scanning electrochemical microscopy. 38. Application of SECM to the study of charge transfer through bilayer lipid membranes.

The use of the scanning electrochemical microscope (SECM) to probe the kinetics of charge-transfer processes at bilayer lipid membranes (BLM) is presented. Analysis of the SECM tip response demonstrates that an unmodified BLM behaves as an insulator, whereas a BLM doped with iodine shows some positive feedback. The SECM technique thus allows one to probe processes at a BLM and determine the kinetics of the charge-transfer process. The SECM can also be used to determine the shape of the BLM.

Electrochemistry↗

PubMed1999

[Research on nitric oxide, oxidative and lipid peroxidative parameters in blood of diabetic patients].

Plasma nitric oxide(P-NO), vitamin C(P-VC), vitamin E(P-VE), beta-carotene (P-beta-CAR), lipoperoxides (P-LPO) contents, the activities of erythrocyte superoxide dismutase(E-SOD), catalase(E-CAT), glutathione peroxidase (E-GSH-Px) and lipoperoxides (E-LPO) in 114 diabetic patients and 100 healthy subjects were measured. Compared with the control group, the average contents of P-NO, P-LPO and E-LPO of patient, were higher (P < 0.01), while P-VC, P-VE, P-beta-CAR contents and E-SOD, E-CAT and E-GSH-Px activities were lower (P < 0.01). With the advance of disease courses, the P-NO, P-LPO and E-LPO contents of diabetic patients increased, while P-VC, P-VE, P-beta-CAR, E-SOD, E-CAT and E-GSH-Px decreased(P < 0.01). The stepwise regression showed that the correlation between disease courses and P-NO, P-VC, E-SOD, E-GSH-Px and E-LPO values was significant. The metabolism of nitric oxide in diabetic patients was abnormal, and the antioxidation, antiperoxidation and antilipoperoxidation were depressed.

Aged↗

PubMed1999

Polycystin-L is a calcium-regulated cation channel permeable to calcium ions.

Polycystic kidney diseases are genetic disorders in which the renal parenchyma is progressively replaced by fluid-filled cysts. Two members of the polycystin family (polycystin-1 and -2) are mutated in autosomal dominant polycystic kidney disease (ADPKD), and polycystin-L is deleted in mice with renal and retinal defects. Polycystins are membrane proteins that share significant sequence homology, especially polycystin-2 and -L (50% identity and 71% similarity). The functions of the polycystins remain unknown. Here we show that polycystin-L is a calcium-modulated nonselective cation channel that is permeable to sodium, potassium and calcium ions. Patch-clamp experiments revealed single-channel activity with a unitary conductance of 137 pS. Channel activity was substantially increased when either the extracellular or intracellular calcium-ion concentration was raised, indicating that polycystin-L may act as a transducer of calcium-mediated signalling in vivo. Its large single-channel conductance and regulation by calcium ions distinguish it from other structurally related cation channels.

Animals↗

PubMed1999

Structure of Tetrahymena GCN5 bound to coenzyme A and a histone H3 peptide.

Gene activation is a highly regulated process that requires the coordinated action of proteins to relieve chromatin repression and to promote transcriptional activation. Nuclear histone acetyltransferase (HAT) enzymes provide a mechanistic link between chromatin destabilization and gene activation by acetylating the epsilon-amino group of specific lysine residues within the aminoterminal tails of core histones to facilitate access to DNA by transcriptional activators. Here we report the high-resolution crystal structure of the HAT domain of Tetrahymena GCN5 (tGCN5) bound with both its physiologically relevant ligands, coenzyme A (CoA) and a histone H3 peptide, and the structures of nascent tGCN5 and a tGCN5/acetyl-CoA complex. Our structural data reveal histone-binding specificity for a random-coil structure containing a G-K-X-P recognition sequence, and show that CoA is essential for reorienting the enzyme for histone binding. Catalysis appears to involve water-mediated proton extraction from the substrate lysine by a glutamic acid general base and a backbone amide that stabilizes the transition-state reaction intermediate. Comparison with related N-acetyltransferases indicates a conserved structural framework for CoA binding and catalysis, and structural variability in regions associated with substrate-specific binding.

Acetyltransferases↗

PubMed1999

Synaptic and neurochemical features of calcitonin gene-related peptide containing neurons in the rat accessory optic nuclei.

Within the rodent visual system, calcitonin gene-related peptide (CGRP) is selectively expressed in neurons in the accessory optic nuclei (AON), including the dorsal terminal nucleus (DTN), lateral terminal nucleus (LTN) and medial terminal nucleus (MTN). To determine whether CGRP-immunoreactive neurons are involved in visual circuitry, electron microscopic preparations were analyzed from normal rats and rats with optic nerve transections. A co-localization analysis was also made because CGRP-labeled neurons had features of GABAergic neurons. Thus, sections were prepared for light microscopy to determine whether CGRP-containing neurons also had glutamate decarboxylase (GAD) and other markers for GABAergic neurons, such as calcium binding proteins: calbindin (CB), calretinin (CR) and parvalbumin (PV). Electron microscopy of the DTN and LTN showed CGRP-labeled somata and dendrites that were postsynaptic to axon terminals forming asymmetric synapses. Many of these axon terminals degenerated following optic nerve transection indicating that retinal ganglion cells form synapses with CGRP-labeled neurons in the AON. In the DTN, LTN and MTN, CGRP-labeled axon terminals formed symmetric synapses with unlabeled somata as well as dendritic shafts and spines. Consistent with this type of synapse being GABAergic were the co-localization data showing that about 90% of the CGRP-labeled neurons co-localized GAD in the AON. Many CGRP-labeled neurons showed immunostaining for CR (40%) whereas only a few had labeling for CB (5%). No CGRP-labeled neurons had PV. These data show that CGRP-containing neurons receive direct retinal input and represent a subpopulation of GABAergic neurons which differentially co-express calcium-binding proteins.

Animals↗