Biomedical subjects

Ping Zheng

Publications and source records attributed to Ping Zheng.

At least 55 records · Page 3Linked to original sources

PubMed2005

Nitrogen removal from sludge dewatering effluent through anaerobic ammonia oxidation process.

Anaerobic ammonia oxidation(Anammox) process is a novel and promising wastewater nitrogen removal process. The feasibility of transition of Anammox from denitrification and the performance of lab-scale Anammox biofilm reactor were investigated with sludge dewatering effluent. The results showed that Anammox process could be successfully started up after cultivation of denitrification biofilm and using it as inoculum. The transition of Anammox from denitrification was accomplished within 85 d. Anammox process was found suitable to remove ammonia from sludge dewatering effluent. The effluent ammonia concentration was detected to be 23.11 mgN/L at HRT of 28 h when influent ammonia concentration was fed 245 mgN/L, which was less than that for the national discharge standard II (25 mgN/L) of China. Volumetric total nitrogen loading rate was up to 584.99 mg TN/(L x d) at HRT of 17 h, while influent concentrations were kept 243.25 mg NH4(+) -N/L and 288.31 mg NO2(-) -N/L.

Ammonia↗

PubMed2004

Effects of follicle size and oocyte maturation conditions on maternal messenger RNA regulation and gene expression in rhesus monkey oocytes and embryos.

The relationship between alterations in gene expression and differences in developmental potential in primate oocytes and embryos was examined. Oocytes from 3 sources were used for these studies: 1) in vivo-matured oocytes from monkeys stimulated with FSH and hCG, 2) in vitro-matured oocytes from large follicles of monkeys primed with FSH, and 3) in vitro-matured oocytes from small follicles from nonstimulated (NS) monkeys. Following in vitro fertilization, embryos from these oocytes displayed high, moderate, and low developmental competence, respectively. Oocytes from NS females displayed aberrant accumulation of a number of maternal mRNAs, followed by precocious loss of many maternal mRNAs by the 2-cell stage. Embryos from NS oocytes displayed alterations in expression of key transcription factors after the 8-cell stage. Oocytes and embryos from FSH-stimulated females also displayed alterations in gene expression relative to hCG-stimulated females, but these alterations were much less severe than those observed for NS oocytes and embryos. Our data are consistent with the hypothesis that continued development and maturation of the oocyte within the ovarian follicle in vivo facilitates the production of oocytes of the highest developmental potential, and that in vitro conditions may not support this process as effectively due to differences in the extracellular milieu. These observations are relevant to understanding the role of the in vivo environment on oocyte maturation, and the potential effects of in vitro maturation on human assisted reproduction methods.

Animals↗

PubMed2004

The primate embryo gene expression resource: a novel resource to facilitate rapid analysis of gene expression patterns in non-human primate oocytes and preimplantation stage embryos.

Detailed molecular studies of preimplantation stage development in a suitable nonhuman primate model organism have been inhibited due to the cost and scarcity of embryos. To circumvent these limitations, we have created a new resource for the research community, designated as the Primate Embryo Gene Expression Resource (PREGER). The PREGER sample collection currently contains over 160 informative samples of oocytes, obtained from various sized antral follicles, and embryos obtained through a variety of different protocols. The PREGER makes it possible to undertake quantitative gene-expression studies in rhesus monkey oocytes and embryos through simple and cost-effective hybridization-based methods. The PREGER also makes available other molecular tools to facilitate nonhuman primate embryology. We used PREGER here to compare the temporal expression patterns of five housekeeping mRNAs and three transcription factor mRNAs between mouse and rhesus monkey. We observed noticeable differences in temporal expression patterns between species for some mRNAs, but clear similarities for others. Our results also provide new information related to genome activation and the effects of embryo culture conditions on gene expression in primate embryos. These results provide one illustration of how the PREGER can be employed to obtain novel insight into primate embryogenesis.

Animals↗

PubMed2004

Expression of genes encoding chromatin regulatory factors in developing rhesus monkey oocytes and preimplantation stage embryos: possible roles in genome activation.

One of the most critical events of preimplantation development is the successful activation of gene transcription. Both the timing and the array of genes activated must be controlled. The ability to regulate gene transcription appears to be reduced just prior to the time of the major genome activation event, and changes in chromatin structure appear essential for establishing this ability. Major molecules that modulate chromatin structure are the linker and core histones, enzymes that modify histones, and a wide variety of other factors that associate with DNA and mediate either repressive or activating changes. Among the latter are chromatin accessibility complexes, SWI/SNF complexes, and the YY1 protein and its associated factors. Detailed information about the expression and regulation of these factors in preimplantation stage embryos has not been published for any species. In order to ascertain which of these factors may participate in chromatin remodeling, genome activation, and DNA replication during early primate embryogenesis, we determined the temporal expression patterns of mRNA encoding these factors. Our data identify the predominant members of these different functional classes of factors expressed in oocytes and embryos, and reveal patterns of expression distinct from those patterns seen in somatic cells. Among each of four classes of mRNAs examined, some mRNAs were expressed predominantly in the oocyte, with these largely giving way to others expressed stage specifically in the embryo. This transition may be part of a global mechanism underlying the transition from maternal to embryonic control of development, wherein the oocyte program is silenced and an embryonic pattern of gene expression becomes established. Possible roles for these mRNAs in chromatin remodeling, genome activation, DNA replication, cell lineage determination, and nuclear reprogramming are discussed.

Acetylation↗

PubMed2004

Identification of a novel enhancer of brain expression near the apoE gene cluster by comparative genomics.

Comparative analysis of the human and mouse genomic sequences downstream of the apolipoprotein E gene (APOE) revealed a highly conserved element with previously undefined function. In reporter gene transfection studies, this element which is located approximately 42 kb distal to APOE was found to have silencer activity in a subset of cell lines examined. Analysis of transgenic mice containing a fusion construct linking this distal 631 bp conserved element to a reporter gene comprised of the human APOE gene with its proximal promoter resulted in robust brain expression of the transgenic human apoE mRNA in three independent transgenic lines, supporting the identification of a novel brain controlling region (BCR). Further studies using immunohistochemistry revealed widespread human apoE localization throughout the brains of the BCR-apoE transgenic mice with prominent expression in the cortex and diencephalon. In addition, double-label immunofluorescence performed on brain sections and cultures of primary cortical cells localized human apoE protein to cortical neurons and microglia. These studies demonstrate that comparative sequence analysis is a successful strategy to predict candidate regulatory regions in vivo, although they do not imply that this element controls apoE expression physiologically.

Animals↗

PubMed2004

Effect of glycerol and dimethyl sulfoxide on cryopreservation of rhesus monkey (Macaca mulatta) sperm.

Glycerol and dimethyl sulfoxide (DMSO) are widely used as penetrating cryoprotectants in the freezing of sperm, and various concentrations are applied in different species and laboratories. The present study aimed to examine the effect of these two cryoprotectants at different concentrations (2%, 5%, 10%, and 15% glycerol or DMSO) on rhesus monkey sperm cryopreservation. The results showed that the highest recovery of post-thaw sperm motility, and plasma membrane and acrosome integrity was achieved when the sperm was frozen with 5% glycerol. Spermatozoa cryopreserved with 15% DMSO showed the lowest post-thaw sperm motility, and spermatozoa cryopreserved with 15% glycerol and 15% DMSO showed the lowest plasma membrane integrity among the eight groups. The results achieved with 5% glycerol were significantly better for all parameters than those obtained with 5% DMSO. The functional cryosurvival of sperm frozen with 5% glycerol was further assessed by in vitro fertilization (IVF). Overall, 85.7% of the oocytes were successfully fertilized, and 51.4% and 5.7% of the resulting zygotes developed into morulae and blastocysts, respectively. The results indicate that the type and concentration of the penetrating cryoprotectant used can greatly affect the survival of rhesus monkey sperm after it is frozen and thawed. The suitable glycerol level for rhesus monkey sperm freezing is 5%, and DMSO is not suitable for rhesus monkey sperm cryopreservation.

Animals↗

PubMed2004

Progesterone inhibition of dopamine-induced increase in frequency of spontaneous excitatory postsynaptic currents in rat prelimbic cortical neurons.

We examined the effects of progesterone on frequency of miniature excitatory postsynaptic currents (mEPSCs) and spontaneous excitatory postsynaptic currents (sEPSCs), and dopamine-induced increase in the frequency of sEPSCs in pyramidal cells of layers V-VI of the rat prelimbic cortex using whole-cell patch-clamp techniques in slices. The results showed that progesterone 100 microM had no effects on the frequency of mEPSCs and sEPSCs, but significantly inhibited dopamine-induced increase in frequency of sEPSCs. This was in contrast to the effect of progesterone on the effect of 5-HT, which showed no changes after progesterone. When studying the mechanism of the progesterone effect, we observed that GABA(A) receptor antagonist and progesterone receptor antagonist did not influence the effect of progesterone; progesterone had no effects on D1 receptor agonist, protein kinase A and protein kinase C activator-induced increase in the frequency of sEPSCs. Interestingly, sigma(1) receptor antagonist could inhibit the effect of dopamine and sigma(1) receptor agonist had a synergistic effect on the effect of D1 receptor agonist. These results suggest that progesterone may inhibit dopamine-induced increase in frequency of sEPSCs in rat prelimbic cortical neurons via inhibition of sigma(1)/D1 receptor synergism because progesterone has been known to be an antagonist of sigma(1) receptor.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed2004

A lipid transfer protein gene BG-14 is differentially regulated by abiotic stress, ABA, anisomycin, and sphingosine in bromegrass (Bromus inermis).

The objective was to investigate the expression of a lipid transfer protein gene (LTP) both in bromegrass (Bromus inermis) cells and seedlings after exposure to abiotic stresses, abscisic acid (ABA), anisomycin, and sphingosine. A full-length cDNA clone BG-14 isolated from bromegrass suspension cell culture encodes a polypeptide of 124 amino acids with typical LTP characteristics, such as a conserved arrangement of cysteine residues. During active stages of cold acclimation LTP expression was up-regulated, whereas at the final stage of cold acclimation LTP transcript level declined to pre-acclimation level. A severe drought stress induced the LTP gene; yet, LTP expression doubled 3 d after re-hydration. Both temperature and heat shock duration influence LTP induction; however temperature is the primary factor. Treatment with NaCl stimulated accumulation of LTP mRNA within 15 min and the transcripts remained at elevated levels for the duration of the salinity stress. Most interestingly, Northern blots showed LTP was rapidly induced not only by ABA, but also by anisomycin and sphingosine in suspension cell cultures. Of the three chemicals, ABA induced the most rapid and highest response in LTP expression as well as highest freezing tolerance, whereas sphingosine was the least active for both LTP expression and freezing tolerance.

Abscisic Acid↗

PubMed2004

Melatonin inhibits outward delayed rectifier potassium currents in hippocampal CA1 pyramidal neuron via intracellular indole-related domains.

In the present study, we investigated the effect of melatonin on the outward delayed rectifier potassium currents (IK) in CA1 pyramidal neurons of rat hippocampal slices using patch-clamp technique in whole-cell configuration. In a concentration-dependent manner, melatonin caused a reduction of IK with a half-maximal inhibitory concentration (IC50) of 3.75 mm. The inhibitory effect had rapid onset and was readily reversible. Melatonin shifted steady-state inactivation of IK in hyperpolarizing direction but did not alter its steady-state activation. Neither luzindole, an MT1/MT2 receptor antagonist, nor prazosin, an MT3 receptor antagonist, blocked melatonin-induced current reduction. The results indicate that melatonin-induced IK inhibition was not via activation of its own membrane receptors. 5-Hydroxytryptamine (5-HT), a melatonin precursor and an agonist of serotonin receptors, when it was given in pipette internal solution but not bath solution, produced a similar inhibitory effect to that of melatonin. Moreover, indole, a major component of melatonin, reversibly and dose dependently inhibited IK with an IC50 of 3.44 mm. Present results suggest that melatonin inhibits IK in hippocampal CA1 pyramidal neurons probably through its interaction with the intracellular indole-related domains of potassium channels.

Animals↗

PubMed2004

Start-up of anaerobic ammonia oxidation bioreactor with nitrifying activated sludge.

The anaerobic ammonia oxidation(Anammox) bioreactor was successfully started up with the nitrifying activated sludge. After anaerobically operated for 105 d, the bioreactor reached a good performance with removal percentage of both ammonia and nitrite higher than 95% and volumetric total nitrogen removal as high as 149.55 mmol/( L.d). The soft padding made an important contribution to the high efficiency and stability because it held a large amount of biomass in the bioreactor.

Ammonia↗

PubMed2004

Performance of Anammox granular sludge bed reactor started up with nitrifying granular sludge.

The anaerobic ammonia oxidation (Anammox) granular sludge bed reactor was started up successfully with nitrifying granular sludge. During the operation, the nitrifying granular sludge was gradually converted into Anammox granular sludge with good settling property and high conversion activity. The Anammox reactor worked well with the shortest HRT of 2.43 h. Under the condition that HRT was 6.39 h and influent concentration of ammonia and nitrite was 10 mmol/L, the removal of ammonia and nitrite was 97.17% and 100.00%, respectively. Corresponding volumetric total nitrogen loading rate and volumetric total nitrogen conversion rate were 100.83 mmol/(L x d) and 98.95 mmol/(L x d). The performance of Anammox reactor was efficient and stable.

Ammonia↗

PubMed2004

[Inhibitory effect of hDAF displayed on yeast cells on deposition of complement on the yeast cells].

AIM: To investigate whether the hDAF displayed on the surface of yeast cells can inhibit the deposition of C5b-9. METHODS: After treatment with normal human serum, deposition of human complement C5b-9 and DAF expression on yeast cells EBY100 were analyzed by flow cytometry. RESULTS: Yeast cells EBY100 could activate the complement molecules in human serum and lead to the deposition of C5b-9, while the deposition of C5b-9 on the surface of yeast cells with hDAF could significantly reduce the deposition of C5b-9. CONCLUSION: hDAF displayed on the surface of yeast cells can fold correctly and exhibit activity of complement's inhibition.

CD55 Antigens↗

PubMed2004

[Management of major cervical vessel injury: clinical experience].

PURPOSE: To review the diagnosis and management of injury of the major cervical vessels. METHODS: The clinical data of 12 cases with injury of the major cervical vessels were analyzed retrospectively. The causes of injury, emergency management, outcomes and complications were investigated. RESULTS: Among 12 cases, no death and no severe complications developed through appropriate management. CONCLUSIONS: For patients with cervical injury, the possibility of vascular injury should be considered. The key to salvage on spot is hemostasis by local compression with rapid filling. Complete exposure of the vessels is the key to success of surgical salvage. Anti-shock measures, endotracheal intubation general anesthesia and immediate operation are mandatory to improvement of treatment outcomes.

Adult↗

PubMed2004

[Profile on circadian blood pressure and the influencing factors in essential hypertensive patients after treatment].

OBJECTIVE: To explore the circadian blood pressure (BP) profile and its influencing factors in essential hypertensive patients after treatment. METHODS: Cross-sectional surveillance was carried out in essential hypertensive subjects after treatment whose clinic blood pressure had been under control as 140/90 mm Hg (1 mm Hg = 0.133 kPa) for at least one month. All patients underwent a twenty-four-hour ambulatory blood pressure monitoring device (spacelabs 90207). The nocturnal fall of blood pressure (BP) was calculated from (daytime mean BP-night-time mean BP)/daytime BP, while 'daytime' values were recorded between 6 h and 22 h and 'night-time' values between 22 h and 6 h. Non-dippers were defined as those whose nocturnal decrease in mean systolic BP and/or mean diastolic BP was < 10% of the daytime BP. Binary logistic regression analysis was used to evaluate the correlation between circadian blood pressure profile and factors as gender, age, height, body mass index (BMI), family history of premature cardiovascular disease, women under age 65 or men under age 55, smoking habits, grade of hypertension, and strategy of antihypertensive drugs. RESULTS: 208 treated essential hypertensive patients were enrolled in the study. 79 individuals were dippers and 129 were non-dippers. Data from logistic regression analysis showed that four factors as age, premature family history of cardiovascular disease, overweight or obesity, and strategy of antihypertensive drugs were significantly influencing the circadian blood pressure profile in treated hypertensive patients. The incidence of non-dippers in patients of 70 years of age or older and those between 60 and 69 were 3.3 and 2.3 times of those with less than 60 (P = 0.009 and 0.031, respectively). The prevalence of non-dippers in patients with a premature family history of cardiovascular disease was 3.7 times greater than those in subjects without a premature history of cardiovascular disease (P = 0.029). Similarly, the incidence of non-dippers in patients of overweight (24 </= BMI < 28) and obesity (BMI >/= 28) were 3.0 and 4.8 times of those in subjects of normal weight (P = 0.003 and 0.009, respectively). Compared with patients treated with long-acting calcium channel blockers (CCBs), patients treated with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) alone had less prevalence of nondippers (OR = 0.139, P = 0.010). Patients treated with joint antihypertensive scheme including ACE inhibitors or ARBs(but not including diuretics) had the tendency of lower incidence of abnormal circadian blood pressure rhythm (OR = 0.453, P = 0.118). Patients treated with joint antihypertensive scheme including diuretics (not including ACE inhibitors or ARBs) and with joint antihypertensive strategy including diuretics and ACE inhibitors or ARBs had lower incidence of nondippers (OR = 0.378 and 0.273, respectively; P = 0.030 and 0.011, respectively). CONCLUSIONS: Approximately 2/3 treated essential hypertensive patients had a non-dipper blood pressure profile. Age, premature family history of cardiovascular disease, overweight/obesity, and antihypertensive drugs strategy were correlated with circadian blood pressure profile. Compared with long-acting CCBs, diuretics, ACE inhibitors or ARBs might be helpful in keeping the circadian blood pressure rhythm at normal range.

Adult↗

PubMed2004

[Construction of C3b(AN42) and OVA(257-264) fusion gene and functional analysis of the fusion protein].

AIM: To explore the role of complement system in the T cell activation. METHODS: OVA(257-264) CTL epitope and C3b(AN42) encoding genes were synthesized and cloned into expression vector pEGFP-N1. COS-7 cells were transfected with the recombinant plasmid pEGFP-N1. The expression of the fusion protein was determined by FACS. Twenty-four hours after transfection, cultural supernatants of the transfected cells were collected and added to Ana-1 cell culture. Laser confocal microscopy was used to detect the binding and presentation of the fusion protein by Ana-1 cells. RESULTS: C3b(AN42)-OVA(257-264) fusion protein was expressed in COS-7 cells. The fusion protein could bind to Ana-1 cells and OVA(257-264) CTL epitope was cross-presented on the surface of Ana-1 cells. CONCLUSION: The C3b(AN42)-OVA(257-264) fusion protein can express in COS-7 cells and possesses natural biological activity.

Animals↗

PubMed2004

Anammox transited from denitrification in upflow biofilm reactor.

Anammox was successfully transited from heterotrophic denitrification and autotrophic denitrification in two upflow biofilm reactors, respectively. The results showed that the volumetric loading rate and nitrogen removal efficiency in the reactor transited from heterotrophic denitrification were higher than that in its counterpart. When the hydraulic retention time was 12 h or so, the total nitrogen loading rate was about 0.609 kg N/(m3 x d), and the effluent ammonia and nitrite concentrations were less than 8.5 mg/L and 2.5 mg/L, respectively. The upflow anammox biofilm reactor was capable of keeping and accumulating the slow-growing bacteria efficiently. During operation of the reactor, the biomass color was gradually turned from brownish to red, and the ratio of ammonia consumption, nitrite consumption and nitrate production approached the theoretical one. These changes could be used as an indicator for working state of the reactor.

Biofilms↗

PubMed2004

[Research on critical aerating flux of internal-loop granular sludge bed nitrifying reactor].

The internal-loop granular sludge bed nitrifying reactor is a new type of aerobic nitrifying equipment and has taken on a good potential for nitrification. The critical aerating flux for liquid loop and critical aerating flux for fluidization of granular sludge are two important parameters for its operation. The relationship between liquid superficial velocity in riser (U1r) and aerating flux(Ugr) was studied, the model parameters were measured by experiment, and the relational expression was established. According to the model, the critical aerating flux for liquid loop and the critical aerating flux for fluidization of granular sludge were calculated as 1.017cm/min and 2.662cm/min, respectively. The experimental data from reactor operation showed that the two calculated critical aerating fluxes near the practical values. So they could be used to direct the design and operating optimization for the internal-loop granular sludge bed nitrifying reactor.

Bacteria, Aerobic↗

PubMed2003

17Beta-estradiol and progesterone improve in-vitro cytoplasmic maturation of oocytes from unstimulated prepubertal and adult rhesus monkeys.

BACKGROUND: Effects of 17beta-estradiol and progesterone on rhesus monkey oocyte maturation in vitro were evaluated by embryo development subsequent to IVF. METHODS AND RESULTS: In experiment 1, immature cumulus-oocyte complexes collected from unstimulated adult females during the non-breeding season were matured in modified medium CMRL-1066 containing various combinations of gonadotrophins (FSH + LH), estradiol and/or progesterone. Formation of morulae and blastocysts was greatest in oocytes matured in medium containing estradiol and/or progesterone, with or without gonadotrophins (morula 38-46%, blastocyst 14-20%) than in control oocytes matured without estradiol or progesterone (morula 14%, blastocyst 0%). In experiment 2, cumulus-oocyte complexes from unstimulated prepubertal female monkeys were matured in medium with gonadotrophins, estradiol or progesterone. The best development to the morula stage was obtained with oocytes matured with gonadotrophins and estradiol or gonadotrophins and progesterone (43 and 25 morulae, respectively), while control oocytes matured with gonadotrophins but without steroid hormones gave the poorest morula developmental response (12%). However, there was no difference in blastocyst development across all groups (0-3%). CONCLUSIONS: These results demonstrate that during rhesus monkey oocyte maturation in vitro: (i) estradiol or progesterone can improve oocyte developmental competence; (ii) immature oocytes from prepubertal versus adult females have differential responses to challenge with estradiol or progesterone.

Aging↗