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Biomedical subjects

Hong Zheng

Publications and source records attributed to Hong Zheng.

At least 37 records · Page 2Linked to original sources
PubMed2006

Switching the recognition preference of rhodamine B spirolactam by replacing one atom: design of rhodamine B thiohydrazide for recognition of Hg(II) in aqueous solution.

A new chemosensor based on rhodamine B thiohydrazide is described. Chemosensor B was found to show a reversible dual chromo- and fluorogenic response toward Hg2+ in aqueous solution in a highly selective and sensitive manner. This was suggested to result from the coordination of Hg2+ at the N, S binding sites in B to open its spiro ring.

Binding Sites↗
PubMed2006

[Liver retransplantation: report of 80 cases].

OBJECTIVE: To sum up the clinical experience of liver retransplantation. METHODS: The clinical data of patients receiving liver retransplantation in our department between Jan. 1999 and July 2005 were retrospectively analyzed, the cause of retransplantation, timing of retransplantation, technical considerations and the causes of death. RESULTS: The most common causes of hepatic graft loss and subsequent retransplantation are biliary complications (45.0%). Patients who received retransplantation more than 30 days after their initial transplant fared better than those who received retransplants between 8 and 30 days after receiving their first one (intraoperative mortality rates 19.6% versus 70.0%). The development of sepsis (54.5%) and multiorgan failure (18.2%) accounts for the majority of deaths in retransplanted patients. CONCLUSIONS: Proper indication and optimum operation time, surgical procedure, perioperative monitoring and proper treatment post operation contribute to the increase of the survival rate of the patients receiving liver retransplantation.

Adolescent↗
PubMed2006

Alcohol-induced impairment of neuronal nitric oxide synthase (nNOS)-dependent dilation of cerebral arterioles: role of NAD(P)H oxidase.

The goal of the present study was to determine the role of NAD(P)H oxidase in alcohol consumption-induced impairment of nNOS-dependent reactivity in cerebral arterioles. Sprague-Dawley rats were fed an alcohol diet for 2-3 months. We measured the effects of acute (1 hour) and chronic (1 month) treatment with a NAD(P)H oxidase inhibitor, apocynin, on responses of parietal pial arterioles to nNOS-dependent agonists (NMDA and kainate) and an nitric oxide synthase (NOS)-independent agonist (nitroglycerin). In addition, we measured the expression of NAD(P)H oxidase subunits and superoxide production in parietal cortex. Topical application of NMDA and kainate produced dose-related dilation of pial arterioles. However, the magnitude of vasodilation to these agonists was significantly less in alcohol-fed rats. Treatment with apocynin (acute and chronic) did not alter vasodilation in nonalcohol-fed rats, but significantly improved vasodilation in alcohol-fed rats. Response of pial arterioles to nitroglycerin was similar in nonalcohol-fed and alcohol-fed rats, and was not affected by apocynin. In addition, we found an up-regulation of gp91phox and p47phox in parietal cortex of alcohol-fed rats. Finally, alcohol consumption produced an increase in superoxide production under basal conditions and in the presence of NADPH. Acute treatment with apocynin suppressed alcohol consumption-induced superoxide generation. Our findings suggest that NAD(P)H oxidase plays an important role in chronic alcohol consumption-induced impairment of nNOS-dependent dilation of cerebral arterioles.

Acetophenones↗
PubMed2006

Rapid induction and activation of Tec tyrosine kinase in liver regeneration.

BACKGROUND: Previous studies have indicated that Tec tyrosine kinase is differentially expressed in the regenerating liver. The purpose of the present study was to further investigate the potential involvement of Tec tyrosine kinase in hepatocyte proliferation and liver regeneration. METHODS: Tec kinase gene expression after partial (two-thirds) hepatectomy was examined by representational difference analysis. Tissue distribution and potential involvement of Tec kinase in liver regeneration and hepatocyte proliferation were then determined by northern blotting, reverse transcription-polymerase chain reaction (RT-PCR), and western blotting. Full-length rat Tec cDNA was cloned. RESULTS: Using this cDNA as the probe, northern blotting showed that Tec was specifically expressed in liver and kidney, the highest expression of Tec being detected in embryonic day 15-19 fetal livers. In contrast, the expression level of Tec in adult and neonatal rat livers was significantly decreased. Similar results were obtained from western blotting analyzes. It was thus hypothesized that Tec might be involved in hepatocyte proliferation. To test this hypothesis, Tec expression was examined in regenerating rat livers. An increase in Tec expression and activation of Tec kinase were observed within 1 h after partial hepatectomy. Moreover, it has been shown that hepatocyte growth factor (HGF) dramatically induces Tec expression in primary rat hepatocytes. Additionally, it was observed that Tec gene expression in serum-starved liver tumor cell line HepG2 was substantially decreased. Stimulation with 10% fetal bovine serum and insulin but not epidermal growth factor resulted in dramatic elevation of Tec expression in these cells. CONCLUSION: Tec is an inducible early response gene that might enhance hepatocyte proliferation and liver regeneration.

Animals↗
PubMed2006

Identification and preliminary characterization of two cDNAs encoding unique carbonic anhydrases from the marine alga Emiliania huxleyi.

Marine coccolithophorid algae are thought to play a significant role in carbon cycling due to their ability to incorporate dissolved inorganic carbon (DIC) into both calcite and photosynthetic products. Among coccolithophorids, Emiliania huxleyi is the most prolific, forming massive blooms that affect the global environment. In addition to its ecological importance, the elaborate calcite structures (coccoliths) are being investigated for the design of potential materials for science and biotechnological devices. To date, most of the research focus in this organism has involved the partitioning of DIC between calcification and photosynthesis, primarily using measurements of an external versus internal carbonic anhydrase (CA) activity under defined conditions. The actual genes, proteins, and pathways employed in these processes have not been identified and characterized (see the work of Quinn et al. in this issue [P. Quinn, R. M. Bowers, X. Zhang, T. M. Wahlund, M. A. Fanelli, D. Olszova, and B. A. Read, Appl. Environ. Microbiol. 72:5512-5526, 2006]). In this study, the cloning and preliminary characterization of two genetically distinct carbonic anhydrase cDNAs are described. Phylogenetic analysis indicated that these two genes belonged to the gamma (gamma-EhCA2) and delta (delta-EhCA1) classes of carbonic anhydrases. The deduced amino acid sequence of delta-EhCA1 revealed that it encodes a protein of 702 amino acids (aa) (ca. 77.3 kDa), with a transmembrane N-terminal region of 373 aa and an in-frame C-terminal open reading frame of 329 aa that defines the CA region. The gamma-EhCA2 protein was 235 aa in length (ca. 24.9 kDa) and was successfully expressed in Escherichia coli BL21(DE3) and purified as an active recombinant CA. The expression levels of each transcript from quantitative reverse transcription-PCR experiments under bicarbonate limitation and over a 24-h time course suggest that these isozymes perform different functions in E. huxleyi.

Amino Acid Sequence↗
PubMed2006

[Application of complete audiological evaluation battery in early hearing aid fitting for deaf children].

OBJECTIVE: To investigate the function of ABR and behavioral test battery in verifying the fitting of hearing aids on deaf children at early stage. METHOD: Fifty-two children of age 1 to 9 were examined with the behavioral test battery or ABR. Based on the hearing thresholds thus obtained, DSL prescriptive formula was used to verify the fitting of hearing aids. Real ear measurement and sound field test were employed to assess the benefit of hearing aid. The children were subsequently followed up on a regular basis. RESULT: There was statistic difference between ABR and behavioral test battery (P < 0.05). Forty-one deaf children demonstrated significant benefit from hearing aid fitting while 4 showed no measurable benefit. CONCLUSION: Both subjective and objective tests should be used for accurate hearing evaluation in deaf children. Hearing aid verification should be conducted accordingly. It is important to carry out early identification, intervention and rehabilitation.

Audiometry↗
PubMed2006

Liver retransplantation: report of 80 cases and review of literature.

BACKGROUND: Because the orthotopic liver transplantation (OLT) was performed widely in recent 5 years throughout China, the proportion of recipients whose graft function deteriorated to be retransplantation candidates increased gradually. This study was undertaken to analyze clinical experience of orthotopic liver retransplantation (re-OLT) at our center. METHODS: The medical records of 80 patients who had undergone liver retransplantation at our center from January 1999 to July 2005 were analyzed retrospectively, including indications and timing of retransplantation, surgical techniques, and the causes of death. RESULTS: The commonest cause leading to hepatic graft loss and subsequent retransplantation was biliary complications in 36 patients (45%). The patients underwent retransplantation more than 30 days after their primary transplant recovered better than those who underwent retransplantation within 8-30 days after primary transplantation (perioperative mortality 19.6% versus 70%). Sepsis (12 of 22 patients, 54.5%) and multiple organ failure (4 of 22 patients, 18.2%) were leading causes of re-OLT recipient deaths. CONCLUSIONS: Proper indications and optimal operative time, surgical procedures, perioperative monitoring and appropriate postoperative treatment contribute to the improvement of the survival rate of patients after liver retransplantation.

Adolescent↗
PubMed2006

[Prediction and management about perilymph gusher in cochlear implantation].

OBJECTIVE: To discuss the clinical experience of prediction and management about perilymph gusher in cochlear implantation. METHOD: Among 327 cases of cochlear implant, eleven recipients were selected by the high resolution computed tomography (HRCT) findings of cochlear malformations and bony fistula on fundus of the internal auditory canal that caused an abnormal connection between subarachnoid and perilymphatic spaces. RESULT: Perilymph gusher was found in all of these 11 recipients during cochlear implantation and was controlled with muscle tissue seal. CONCLUSION: The reason of perilymph gushers in cochlear implantation is that abnormal connection between subarachnoid and internal auditory canal. HRCT can be used to assess the possibility of perilymph gusher in surgery. The safe and rapid surgical method of gusher controlling can avoid complication.

Cerebrospinal Fluid Otorrhea↗
PubMed2006

Nucleocapsid amino acids 211 to 254, in particular, tetrad glutamines, are essential for the interaction between the nucleocapsid and membrane proteins of SARS-associated coronavirus.

GST pull-down assays were used to characterize the SARS-CoV membrane (M) and nucleocapsid (N) interaction, and it was found that the amino acids 211-254 of N protein were essential for this interaction. When tetrad glutamines (Q) were replaced with glutamic acids (E) at positions of 240-243 of the N protein, the interaction was disrupted.

Amino Acid Substitution↗
PubMed2006

[Study on the association of polymorphisms in homocysteine metabolism related enzymes with deep venous thrombosis].

OBJECTIVE: To explore the significance of gene mutation of methylenetetrahydrofolate reductase (MTHFR) C677T, methionine synthase (MS) 2756 AG and cystathionine beta-synthase (CBS) 844ins68 in the development of deep venous thrombosis. METHODS: One hundred and three cases of deep venous thrombosis (DVT group) and 250 healthy subjects (control group) were recruited in the study. The polymorphisms of MTHFR C677T, MS A2756G and CBS 844ins68 were detected by PCR-restriction fragment length polymorphism(PCR-RFLP). RESULTS: The prevalences of TT genotypes of MTHFR (C677T) between DVT group and normal control group had significant difference (27.2% vs 17.2%, P< 0.05), the prevalence of AG genotypes of MS A2756G in the DVT group was less than that in the control group (9.7% vs 19.2%, P< 0.05). The prevalence of 677T-2756A haplotype in the DVT group was higher than that in the control group (P< 0.05), the prevalence of 677C-2756A haplotype in the DVT group was less than that in the control group (P< 0.05). There were no significant differences in the prevalences of CBS 844ins68 mutation. CONCLUSION: The homozygote of MTHFR C677T (TT) may be a risk factor of DVT. MS A2756 G(AG) genotypes may reduce the development of DVT. The 677T-2756A haplotype may be a risk factor of DVT. The 677C-2756A haplotype may be a protective factor of DVT. The prevalence of gene mutation of CBS 844ins68 might vary with different ethnic group or geographic regions.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed2005

Role of NAD(P)H oxidase in alcohol-induced impairment of endothelial nitric oxide synthase-dependent dilation of cerebral arterioles.

BACKGROUND AND PURPOSE: Our goal was to determine whether NAD(P)H oxidase is involved in impaired endothelial nitric oxide synthase (eNOS)-dependent reactivity of cerebral arterioles during chronic alcohol consumption. METHODS: Sprague-Dawley rats were fed with an alcohol diet for 2 to 3 months. We determined the effects of acute and chronic treatment with an NAD(P)H oxidase inhibitor, apocynin, on responses of pial arterioles to eNOS-dependent agonists (acetylcholine and ADP) and an eNOS-independent agonist (nitroglycerin). Expression of NAD(P)H oxidase in pial arterioles was measured with the use of real-time polymerase chain reaction and Western blot analysis, and superoxide production was measured with the use of lucigenin-enhanced chemiluminescence. RESULTS: Vasodilation in response to acetylcholine and ADP, but not nitroglycerin, was significantly less in alcohol-fed rats. Treatment with apocynin did not alter vasodilation in non-alcohol-fed rats but significantly improved impaired vasodilation in alcohol-fed rats. In addition, an upregulation of p47phox in pial arterioles was found in alcohol-fed rats. Furthermore, alcohol consumption increased superoxide production under basal conditions and in the presence of ADP and NAD(P)H. CONCLUSIONS: Our findings suggest that NAD(P)H oxidase plays a role in chronic alcohol consumption-induced impairment of eNOS-dependent dilation of cerebral arterioles.

Acetophenones↗
PubMed2005

Blunted nitric oxide-mediated inhibition of sympathetic nerve activity within the paraventricular nucleus in diabetic rats.

Recent evidence suggests that a central mechanism may be contributing to the sympathetic abnormality in diabetes. Nitric oxide (NO) has been known as a neurotransmitter in the central nervous system. The goal of this study was to examine the role of the endogenous NO system of the paraventricular nucleus (PVN) in regulation of renal sympathetic nerve activity (RSNA) in streptozotocin (STZ)-induced diabetic rats. The change in number of NADPH-diaphorase-positive neurons [a marker for neuronal NO synthase (nNOS) activity] in the PVN was measured. Diabetic rats were found to have significantly fewer nNOS positive cells in the PVN than in the control group (120 +/- 11 vs. 149 +/- 13, P < 0.05). Using RT PCR, Western blotting and immunofluorescent staining, it was also found that nNOS mRNA expression and protein level in the PVN were significantly decreased in the diabetic rats. Furthermore, using an in vivo microdialysis technique, we found that there was a lower NO(x) release from the PVN perfusates in rats with diabetes compared with the control rats (142 +/- 33 nM vs. 228 +/- 29 nM, P < 0.05). In alpha-chloralose- and urethane-anesthetized rats, an inhibitor of NO synthase, l-NMMA, microinjected into the PVN produced a dose-dependent increase in RSNA, mean arterial pressure (MAP), and heart rate (HR) in both control and diabetic rats. These responses were significantly attenuated in rats with diabetes compared with control rats (RSNA: 11 +/- 3% vs. 35 +/- 3%, P < 0.05). On the other hand, an NO donor, sodium nitroprusside (SNP), microinjected into the PVN produced a dose-dependent decrease in RSNA, MAP, and HR in the control and diabetic rats. RSNA (17 +/- 3%, vs. 41 +/- 6%, P < 0.05) and MAP in response to SNP were significantly blunted in the diabetic group compared with the control group. In conclusion, these data indicate an altered NO mechanism in the PVN of diabetic rats. This altered mechanism may contribute to the increased renal sympathetic neural activity observed in diabetes.

Animals↗
PubMed2005

Modulation of androgen receptor transactivation by FoxH1. A newly identified androgen receptor corepressor.

Androgen signaling plays key roles in the development and progression of prostate cancer, and numerous ongoing studies focus on the regulation of androgen receptor (AR) transactivity to develop novel therapies for the treatment of androgen-independent prostate cancer. FoxH1, a member of the Forkhead-box (FOX) gene family of transcription factors, takes part in mediating transforming growth factor-beta/activin signaling through its interaction with the Smad2.Smad4 complex. Using a series of experiments, we found that FoxH1 repressed both ligand-dependent and -independent transactivation of the AR on androgen-induced promoters. This action of FoxH1 was independent of its transactivation capacity and activin A but relieved by Smad2.Smad4. In addition, the repression of the AR by FoxH1 did not require deacetylase activity. A protein-protein interaction was identified between the AR and FoxH1 independently of dihydrotestosterone. Furthermore, a confocal microscopic analysis of LNCaP cells revealed that the interaction between the AR and FoxH1 occurred in the nucleus and that FoxH1 specifically blocked the foci formation of dihydrotestosterone-activated AR, which has been shown to be correlated with the AR transactivation potential. Taken together, our results indicate that FoxH1 functions as a new corepressor of the AR. Our observations not only strengthen the role of FoxH1 in AR-mediated transactivation but also suggest that therapeutic interventions based on AR-coregulator interactions could be designed to block both androgen-dependent and -independent growth of prostate cancer.

Activins↗
PubMed2005

Peptide domain involved in the interaction between membrane protein and nucleocapsid protein of SARS-associated coronavirus.

Severe acute respiratory syndrome (SARS) is an emerging infectious disease associated with a novel coronavirus (CoV) that was identified and molecularly characterized in 2003. Previous studies on various coronaviruses indicate that protein-protein interactions amongst various coronavirus proteins are critical for viral assembly and morphogenesis. It is necessary to elucidate the molecular mechanism of SARS-CoV replication and rationalize the anti-SARS therapeutic intervention. In this study, we employed an in vitro GST pull-down assay to investigate the interaction between the membrane (M) and the nucleocapsid (N) proteins. Our results show that the interaction between the M and N proteins does take place in vitro. Moreover, we provide an evidence that 12 amino acids domain (194-205) in the M protein is responsible for binding to N protein. Our work will help shed light on the molecular mechanism of the virus assembly and provide valuable information pertaining to rationalization of future anti-viral strategies.

Amino Acid Sequence↗
PubMed2005

Inactivation of the invasion inhibitory gene IIp45 by alternative splicing in gliomas.

The invasion inhibitory protein 45 (IIp45) we recently identified was underexpressed in glioblastoma multiforme, the most malignant form of glioma. The IIp45 gene is located at chromosome 1p36 where frequent deletions have been reported in various types of tumors, including gliomas, raising the possibility that IIp45 may be a classic tumor suppressor gene that can be inactivated by frequent point mutations. To test this hypothesis, we sequenced the IIp45 gene in 59 diffuse glioma samples of different grades and histologic subtypes and identified a possible point mutation or a rare polymorphism in only one sample (1.7%), suggesting that IIp45 is not a classic tumor suppressor gene such as p53. Instead, reverse transcription-PCR and subsequent sequencing results revealed a tumor-specific IIp45 spliced isoform (IIp45S) in 20 of 59 (34%) gliomas examined, particularly in glioblastoma multiformes, including native tissue samples (15 of 25; 60%) and cell lines (5 of 5; 100%). The alternative splicing event is independent of 1p36 deletion, which is not common in glioblastoma multiforme. The IIp45S transcript was not detected in any of 18 normal organs, including fetal and adult brain. We determined that the IIp45S isoform results from exclusion of IIp45 exon 7 and encodes a variant protein that carries a COOH terminus different from that of IIp45 due to a frame-shift mutation. IIp45S protein was undetectable in glioma tissues, although IIp45S mRNA was prevalent. We found that IIp45S, once translated, is rapidly degraded by an ubiquitin-proteasome mechanism. Thus, the IIp45 gene is inactivated by a tumor-specific alternative splicing that generates an aberrant and unstable IIp45 isoform in infiltrative gliomas.

Alternative Splicing↗
PubMed2005

Ligustrazine attenuates acute lung injury after burn trauma.

Acute lung injury is a common complication in patients with extensive burns in which the burned area exceeds 30% of the total body surface area (TBSA). This study was undertaken to evaluate the effect of Ligustrazine on burn-induced lung injury as well as the release of interleukin-8 (IL-8) in rats to characterize the role of Ligustrazine and IL-8 in lung injury after burn trauma. Sprague-dawley rats were divided into three groups: (1) sham group, rats who underwent sham burn; (2) control group, rats given third-degree burns over 30% TBSA and lactated Ringer solution for resuscitation; and (3) Ligustrazine group, rats given burn injury and lactated Ringer's solution with Ligustrazine inside for resuscitation. Pulmonary injury was assessed at 24 h by pulmonary capillary permeability determined with fluorescein isothiocyanate-labeled albumin and lung histologic analysis, and lung myeloperoxidase (MPO) activity as well as lung wet/dry weight ratio. The IL-8 levels were measured in serum by enzyme-linked immunosorbent assay. These studies showed that burn trauma results in increased pulmonary leakage permeability and lung wet/dry ratio, elevated serum IL-8 levels and MPO activity, and worsened histologic condition. Ligustrazine inhibited these changes, prevented burn-mediated lung injury, and the production of IL-8. This will likely provide further evidence for ligustrazine as a therapeutic strategy in burn-induced lung injury.

Acute Disease↗
PubMed2005

Exercise training improves endogenous nitric oxide mechanisms within the paraventricular nucleus in rats with heart failure.

Previously, we have demonstrated that an altered endogenous nitric oxide (NO) mechanism within the paraventricular nucleus (PVN) contributes to increased renal sympathetic nerve activity (RSNA) in heart failure (HF) rats. The goal of this study was to examine the effect of exercise training (ExT) in improving the endogenous NO mechanism within the PVN involved in the regulation of RSNA in rats with HF. ExT significantly restored the decreased number of neuronal NO synthase (nNOS)-positive neurons in the PVN (129 +/- 17 vs. 99 +/- 6). nNOS mRNA expression and protein levels in the PVN were also significantly increased in HF-ExT rats compared with HF-sedentary rats. To examine the functional role of NO within the PVN, an inhibitor of NOS, N(G)-monomethyl-L-arginine, was microinjected into the PVN. Dose-dependent increases in RSNA, arterial blood pressure (BP), and heart rate (HR) were produced in all rats. There was a blunted increase in these parameters in HF rats compared with the sham-operated rats. ExT significantly augmented RSNA responses in rats with HF (33% vs. 20% at the highest dose), thus normalizing the responses. The NO donor sodium nitroprusside, microinjected into the PVN, produced dose-dependent decreases in RSNA, BP, and HR in both sham and HF rats. ExT significantly improved the blunted decrease in RSNA in HF rats (36% vs. 17% at the highest dose). In conclusion, our data indicate that ExT improves the altered NO mechanism within the PVN and restores NO-mediated changes in RSNA in rats with HF.

Animals↗