Biomedical subjects

Hui Zhou

Publications and source records attributed to Hui Zhou.

At least 37 records · Page 2Linked to original sources

PubMed2006

Chromatin assembly factor 1 interacts with histone H3 methylated at lysine 79 in the processes of epigenetic silencing and DNA repair.

In eukaryotic cells, chromatin is classified into euchromatin, which is active in transcription, and heterochromatin that silences transcription. Histones in these two domains contain distinct modifications. Chromatin assembly factor 1 (CAF-1) is a highly conserved protein that functions in DNA replication, DNA repair, and heterochromatin silencing. CAF-1 binds histones H3 and H4 and deposits histones onto DNA to form nucleosomes. However, modifications on H3 and H4 associated with CAF-1 are not known. Here, we have purified a complex containing CAF-1 and H3 and H4 from yeast cells and determined the modifications present on these histones using linear ion trap FT-ICR mass spectrometry. H4 that copurified with CAF-1 was a mixture of isoforms acetylated at lysines 5, 8, 12, and 16, whereas an H3 peptide methylated at lysine 79 and an H3 peptide acetylated at lysine 56 were detected. In yeast cell extracts, these two H3 modifications peaked in the late S phase with different kinetics. Moreover, the association of CAF-1 with H3 methylated at lysine 79 appeared to occur in the late S phase. Finally, cells lacking both Dot1p, the methyltransferase that methylates H3 lysine 79, and Cac1p, the large subunit of CAF-1, exhibited a dramatic loss of telomeric silencing and increased sensitivity to DNA damaging agents. Together, these data indicate that CAF-1 interacts with H3 methylated at lysine 79 during the processes of epigenetic silencing and DNA repair.

Amino Acid Sequence↗

PubMed2006

Synthesis and alkaline earth metal cation extraction by proton di-ionizable p-tert-butylcalix[4]arene-crown-5 compounds in cone, partial-cone and 1,3-alternate conformations.

Synthetic strategies for novel, proton di-ionizable p-tert-butylcalix[4]arene-crown-5 compounds in cone, partial-cone and 1,3-alternate conformations are reported. Selective linkage of the two diametrical phenolic oxygens in p-tert-butylcalix[4]arene with tetraethylene glycol ditosylate gave 1,3-bridged p-tert-butylcalix[4]arene-crown-5. The two remaining phenolic units were alkylated using NaH and KH as the bases to give the cone and partial-cone conformers, respectively. Preparation of the 1,3-alternate conformers utilized a different sequence in which O-alkylation was followed by crown ether ring formation. Structures of these new ligands were elucidated by (1)H and (13)C NMR spectroscopy. These proton-ionizable ligands were tested for their solvent extraction properties toward alkaline earth metal cations. Surprising differences in their extraction behaviors are noted compared to those reported previously for di-ionizable p-tert-butylcalix[4]arenecrown-6 analogues.

Journal Article↗

PubMed2006

Characterization of three novel imprinted snoRNAs from mouse Irm gene.

Most, if not all, of snoRNAs in mammals are intron-encoded, implying the expressional and functional relativeness between the snoRNA and their hosts. By computational analysis of an intron database extracted from 65 known mouse imprinted genes, three novel orphan box C/D snoRNAs were identified from Irm gene which is maternally expressed and related to human disorders. The snoRNAs were positively detected and found to express in all the mouse tissues except kidney. The imprinted snoRNAs exhibit stringent structures, but quite variable in locations at their host introns, suggesting their maturation probably through a splicing independent manner. We characterized Irm as a new kind of snoRNA host gene which has no protein-coding capacity and no 5'TOP structure in its mRNA. The newly identified snoRNAs appear mouse-specific, however, their function remains to be elucidated.

Animals↗

PubMed2006

Electrochemical study of photovoltaic effect of nano titanium dioxide on hemoglobin.

Nano titanium dioxide (TiO2) and hemoglobin (Hb) were co-modified on pyrolytic graphite (PG) electrode to study the photovoltaic effect of TiO2 nanoparticles (NPs) on the electron transfer reactivity and catalytic activity of the protein. By means of cyclic voltammetry (CV) and FTIR measurements, the study was characterized in both aerobic and anaerobic environments. Experimental results revealed that the factors which mainly interacted with Hb were electron/hole pairs and reactive oxygen species (ROS) generated by the photovoltaic effect when TiO2 NPs were irradiated under ultraviolet (UV) light. The electron/hole pairs generated on the surface of TiO2 would influence the structure of Hb gently, so the electron transfer reactivity and catalytic ability of the protein slightly changed. In contrast, ROS interacted with Hb intensively, which brought in much conformational change to Hb and its active centers, and even cause some damage. Consequently, the electron transfer reactivity and catalytic activity of Hb changed with a process of increasing initially and decreasing afterwards.

Adsorption↗

PubMed2006

Innate stimuli accentuate end-organ damage by nephrotoxic antibodies via Fc receptor and TLR stimulation and IL-1/TNF-alpha production.

Innate stimuli are well recognized as adjuvants of the systemic immune response. However, their role in driving end-organ disease is less well understood. Whereas the passive transfer of glomerular-targeting Abs alone elicited minimal renal disease, the concomitant delivery of innate stimuli triggered severe nephritis, characterized by proliferative glomerulonephritis with crescent formation, and tubulointerstitial disease. Specifically, stimulating TLR2, TLR3, TLR4, and TLR5 by using peptidoglycan, poly(I:C), LPS, and flagellin, respectively, all could facilitate anti-glomerular Ab-elicited nephritis. In this model, innate and immune triggers synergistically activated several cytokines and chemokines, including IL-1, IL-6, TNF-alpha, and MCP-1, some of which were demonstrated to be absolutely essential for the development of renal disease. Genetic studies revealed that, whereas the innate trigger is dependent on TLR/IL-1R-associated kinase-mediated signaling, the immune component was contingent on FcR-mediated signals. Importantly, infiltrating leukocytes as well as intrinsic glomerular cells may both serve to integrate these diverse signals. Extrapolating to spontaneous immune-mediated nephritis, although the adaptive immune system may be important in generating end-organ targeting Abs, the extent of damage inflicted by these Abs may be heavily dependent on cues from the innate immune system.

Adjuvants, Immunologic↗

PubMed2006

Primary peripancreatic lymph node gastrinoma in a woman with MEN1.

A 39-year-old woman was admitted to hospital due to perforated relapsing duodenal ulcer. Clinical, laboratory, and surgical examinations revealed a peripancreatic lymph node gastrinoma as the cause of Zollinger-Ellison syndrome. Further examinations established multiple endocrine neoplasia type 1 (MEN1) with a germline mutation at codon 1153 (T->A) in exon 7, causing an amino-acid change, from isoleucine to asparagine (Ile348Asn), in the MEN1 gene. The following findings strongly supported a diagnosis of primary lymph node gastrinoma: a rapid fall of the serum gastrin level after operation, the continuous normalization of the serum gastrin level before and after secretin stimulation, the lack of any symptoms, and the absence of another tumor for 13 years after surgical resection of the tumor-bearing lymph node. A review of similar cases in the world literature reveals that not all gastrinomas in lymph nodes are the result of metastastic spread. A long-term symptom-free follow-up after the excision of a lymphnode gastrinoma is the only reliable criterion for the diagnosis of a primary lymph node tumor. To our knowledge, this is the only well-documented case of a primary lymph node gastrinoma in a patient with MEN1. Our case supports the idea that any gastrinoma in patients with MEN1 should be surgically resected for cure if possible.

Adult↗

PubMed2006

The technical development of crystals and oscillators in China and their market situation.

In recent years the manufacture of and demand for crystals and oscillators in China have been increasing quickly because of the development of industries, communications, science, transportation, and electronic techniques. This paper introduces the manufacture, research, and characteristics of the technical development of crystals and oscillators in the last ten years in China. To meet the demand from industry, science, and other markets, the number of companies that produce and research crystals and oscillators has increased from several to more than 300 in the last 20 years. Manufacturing technology and equipment have also improved. For marketing and technical reasons, more than 75% of the companies manufacture mainly 49 micro, 49 micros, and microm crystals. Now more and more companies plan to build production lines to make cold-weld crystals and other precision crystals, and at least two companies have already built their production lines. Most of the precision crystals are AT-cut but some are SC-cut. Integrated TCXOs and DTCXOs have been made by different companies, and the frequency-temperature stability of them is from +/- 2 ppm to +/- 0.5 ppm in a wide temperature range. Specifications of some OCXOs are almost the same as those of foreign OCXOs. The main design techniques in China are experimental. However, in recent years, specially designed software has been developed for oscillator design, and advanced instrumentation and equipment are used. The market situation for crystals and oscillators has increased.

Journal Article↗

PubMed2006

The expression and significance of CATSPER1 in human testis and ejaculated spermatozoa.

AIM: To investigate the distribution of cation channel of sperm 1 (CATSPER1) protein and the presence of CATSPER1 mRNA in human testis and ejaculated spermatozoa. The influence of anti-human CATSPER1 antibody upon human sperm motility was used to evaluate the function of human CATSPER1 and to estimate its possible use as a target for immunocontraception. METHODS: Human ejaculated sperm from normozoospermic donors (n = 12) and liquid nitrogen frozen human testis were used for the study of mRNA and protein expression of CATSPER1 by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. Spermatozoa from normozoospermic donors (n = 12) were individually processed using a swim-up procedure and were then incubated with CATSPER1 antibody at final concentrations of 20, 4 and 0.8 microg/mL. After 1, 2 and 6 h incubation, progressive motility and fast progressive motility were measured by means of computer-assisted semen analysis. RESULTS: CATSPER1 transcript was detected in both human testis and each human ejaculated semen sample. CATSPER1 protein expressed in the membrane of spermatid and was localized in the principal piece of the sperm tail. The application of CATSPER1 antibody at all concentrations significantly inhibited both progressive motility and fast progressive motility after 1, 2 and 6 h incubation, and significant dose-dependent changes were observed. CONCLUSION: CATSPER1 is meiotically and post-meiotically expressed in human testis tissue. CATSPER1 mRNA in human ejaculated spermatozoa could be a more feasible target for study and infertility screening than testis biopsy. In addition, our results suggest that human CATSPER1 could be a possible target for immunocontraception.

Antibodies↗

PubMed2006

[The structure, function and recent reseach of pRNA].

In the bacteriophage phi29, a virus-encoded RNA(pRNA) is required for the packaging of its genomic DNA. Six pRNAs form a hexamer through pRNA/pRNA interaction to drive the DNA translocation motor, and ATP as the energy resource. Chimeric pRNAs can steadily combine with siRNA, ribozymes and anti-sense RNA, and then be transferred into the cancer cells and viral-infected cells by RNA nanotechnology. The continued study of pRNA will help us to understand the origin of the life and explore its possible applications.

Bacillus Phages↗

PubMed2006

Baculovirus-mediated gene expression in chicken primary cells.

A recombinant baculovirus was constructed containing an expression cassette with a reporter gene, green fluorescent protein, directed by a constitutive mammalian promoter: a human cytomegalovirus immediate early promoter/enhancer (CMV-IE). High titer virus was prepared with ultracentrifugation. Efficient gene delivery and expression were observed in the virus-treated chicken primary culture, myoblast cells, and whole embryonic fibroblast cells. It was noticed that an addition of sodium butyrate (a selective histone deacetylase inhibitor) to viral transduction medium extremely enhanced the reporter-gene expression. However, there is no effect of presence of trichostatin A observed. To maximize the reporter-gene expression, the baculoviral infection condition was optimized with both cell types. Our approaches demonstrated that recombinant baculovirus could efficiently deliver its genome DNA into chicken primary cells and that CMV-IE, a mammalian-cell-active promoter, was functional in chicken primary cells and could direct a high level of gene expression. Clearly, the recombinant baculovirus provides an alternative means for foreign gene delivery into avian cells.

Animals↗

PubMed2006

Electrochemistry of xanthine oxidase and its interaction with nitric oxide.

With the help of nanocrystalline TiO2, the direct electrochemistry of xanthine oxidase (XOD) was achieved and two pairs of redox waves were observed. The interaction between XOD and nitric oxide (NO) was also investigated. The experimental results reveal that NO can be reduced at a XOD-nano TiO2 film modified electrode. When the NO concentration was low, the reduced product, HNO, would inactivate the protein. However, when the NO concentration was high, HNO would continue to react with NO to form N2O2- and N3O3-, which would not inhibit XOD, and thus the amount of active protein did not decrease any further.

Animals↗

PubMed2006

[Effects of Tongluo recipe on experimental diabetic peripheral neuropathy in rats].

OBJECTIVE: To investigate the effects of Tongluo Recipe (TLR), a compound Chinese herbal medicine, on experimental diabetic peripheral neuropathy in rats. METHODS: Diabetes was induced by streptozocin in rats. Eight weeks later, the diabetic rats were assigned to 3 groups according to different body weights: untreated group, low-dose TLR-treated group and high-dose TLR-treated group. Eight normal rats were assigned to normal control group. Systemic and sciatic nerve intrinsic antioxidant enzyme activities, lipid peroxide levels, hemorheology and sciatic nerve conduction velocity and ultrastructure changes were evaluated. RESULTS: Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were lower, and lipid peroxide levels were higher in plasma and sciatic nerve of the untreated group than those in the normal control group (P<0.05). Blood glucose and viscosity in the untreated group were higher than those in the normal control group. Sciatic nerve showed demyelination changes and decrease of conduction velocity. Vasa nervorum expanded and erythrocyte deposited in the capillary in the untreated group. TLR obviously improved sciatic nerve conduction velocity and ameliorated morphology changes, decreased blood viscosity, improved SOD and GSH-Px activities. CONCLUSION: TLR can obviously improve sciatic nerve function and ameliorate morphology changes in rats with diabetic peripheral neuropathy, probably through depleting free radical production, improving endothelial cell function and ameliorating hemorheology changes.

Animals↗

PubMed2006

[Study on mitochondrial DNA genetic diversity of Tibetan antelope].

With noninvasive DNA genotyping technology, we investigated genetic diversity of Tibetan antelope by analyzing mitochondrial DNA variationìthose samples are collected from Hoh Xil National Nature Reserve, Qinghai province, China. A total of 444-446 bp of the mitochondrial control region was sequenced form 10 individuals. The results showed that A% + T%(61.8%) was higher than C%+G% (38.2%) obviously. Ten haplotypes were identified in the 10 samples. The result showed 48 polymorphic sites after comparisons of the 10 haplotype samples, among them, including 44 transitions, 1 transversion, 1 insertion and 2 deletions. The average genetic distance of haplotypes is 0.031. The haplotypic diversity is 1.000. The nucleotide diversity is 0.0296. The average number of nucleotide differences is 13.127. It showed that the Tibetan antelope population has high variation in mitochondrial D-loop sequence.

Animals↗

PubMed2006

[Neuroprotective effect of BDNF on hypoxia for embryonic rat cortical neurons in vitro].

OBJECTIVE: To investigate the neuroprotective function of BDNF on hypoxic- cultured neurons in vitro. METHODS: The embryonic cerebral cortical neurons of rat were cultured in vitro in hypoxic and non-hypoxic environments and were observed under transmission electron microscope. MTT colorimetry was used to detect the viability of the neurons. Both DAPI colorated measurement and TUNEL methods were used to calculate the percentages of neuron apoptosis. Three groups were designed and compared: Group A - normal control; Group B - exposed to hypoxia; Group C-BDNF intervened (with different dosages and durations) and exposed to hypoxia. RESULTS: The ultrastructural alterations of the hypoxic cultured neurons indicated that hypoxia induced necrosis, apoptosis or both. The neurons were most sensitive to hypoxia at the initial 10 hours. At six hours after hypoxic cultures, Group C had significant greater livability of neurons and less percentages of neuron apoptosis than Group B (P<0.05). CONCLUSION: Hypoxia damages embryonic cerebral cortical neurons of rat in vitro. Extrinsic BDNF plays a neuroprotective role against hypoxic-induced neurotoxicity in vitro.

Animals↗

PubMed2006

[Qualitative detection of hepatitis C virus core antigen in the serum in patients with chronic hepatitis C].

OBJECTIVE: To evaluate the clinical significance of serum hepatitis C virus (HCV) core antigen detected by enzyme linked immunosorbent assay (ELISA). METHODS: The serum HCV core antigen, which was taken from 149 patients with chronic hepatitis C, 20 patients of chronic hepatitis B and 20 health volunteers, was detected by ELISA. Meanwhile, the serum HCV RNA was detected by RT-PCR, and anti-HCV was detected by ELISA. RESULTS: The qualitative HCV core antigen in the serum, which was take from 20 patients of chronic hepatitis B and 20 health volunteers, was negative.The positive percentage of HCV core antigen was 49.66% in the 149 sera of patients with chronic hepatitis C. The coincidence of detective results of HCV RNA and HCV core antigen was 54.36%, without significant difference (P>0.05). The positive percentage of HCV RNA and HCV core antigen in the 149 anti-HCV antibody positive sera samples were 55.03% (82/149) and 49.66% (74/149), respectively, and there was no significant difference (P>0.05). CONCLUSION: The qualitative HCV core antigen detected by ELISA has a high specificity. The positive percentage of HCV core antigen in the serum of patients with chronic hepatitis C is 49.66%. HCV core antigen is related to HCV RNA. HCV core antigen may be a useful serum marker which could show HCV viraemia like HCV RNA.

Hepatitis C Antigens↗

PubMed2005

The influence of defects on the morphology of Si (111) etched in NH4F.

We have implemented a kinetic Monte Carlo (KMC) simulation to study the effects of wafer miscut and wafer defects on the morphologies of Si (111) surfaces etched in NH4F. Although a conventional KMC simulation reproduced previously published results, it failed to produce the morphologies observed in our experiments. By introducing both dopant sites and lattice defect sites into the model, we are able to simulate samples having different dopant elements and densities as well as different defect concentrations. Using the modified KMC simulation, the simulated surface morphologies agree well with the morphologies observed in our experiments. The enhanced model also gives insights to the formation mechanism for multiple level stacking pits, a notable morphology on the etched surfaces of samples with very small miscut angles.

Journal Article↗

PubMed2005

A novel experimental approach for systematic identification of box H/ACA snoRNAs from eukaryotes.

Box H/ACA snoRNAs represent an abundant group of small non-coding RNAs mainly involved in the pseudouridylation of rRNAs and/or snRNAs in eukaryotes and Archaea. In this study, we describe a novel experimental method for systematic identification of box H/ACA snoRNAs from eukaryotes. In the specialized cDNA libraries constructed by this method with total cellular RNAs from human blood cells, the high efficiency of cloning for diverse box H/ACA snoRNAs was achieved and seven novel species of this snoRNA family were identified from human for the first time. Furthermore, the novel method has been successfully applied for the identification of the box H/ACA snoRNAs from Drosophila and the fission yeast, demonstrating a powerful ability for systematic analysis of box H/ACA snoRNAs in a broad spectrum of eukaryotes.

Animals↗

PubMed2005

Spatial expression of germ cell markers during maturation of human fetal male gonads: an immunohistochemical study.

BACKGROUND: The aim of the present study was to examine fetal male germ cells for expression of proteins associated with differentiation and maturation and to compare them with morphologically defined subpopulations. METHODS: Testes of 61 fetuses from week 12 of gestation to the newborn period were selected. Immunohistochemistry was performed using antibodies to proteins associated with differentiation of germ cells (c-KIT, AP-2gamma) or pluripotency (OCT3/4), oncofetal protein M2A and spermatogonial marker MAGE-A4. RESULTS: Two subtypes of fetal germ cells were detected by quantification and immunohistochemistry. Nearly all germ cells with morphological criteria of gonocytes and intermediate cells co-expressed OCT3/4, c-KIT, M2A and AP-2gamma. Starting from week 12, their number increased up to week 18/19 and then declined continuously during further development. After week 25, pre-spermatogonia were predominant and expressed MAGE-A4 selectively. CONCLUSIONS: Fetal male germ cells are comprised of two major groups with distinct immunohistochemical phenotypes. Germ cells that are predominantly found before week 25 of gestation co-express oncofetal proteins OCT3/4, c-KIT, M2A and AP-2gamma. After week 25, most germ cells have lost their pluripotent potential and acquire a spermatogonial phenotype defined by expression of MAGE-A4.

Antigens, Neoplasm↗