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Biomedical subjects

Wei Hong

Publications and source records attributed to Wei Hong.

At least 37 records · Page 2Linked to original sources
PubMed2004

Neuroprotective effects of Hypericum perforatum on trauma induced by hydrogen peroxide in PC12 cells.

The standard extracts of Hypericum perforatum L. (SEHP), a well-known medicinal plant, are used for the treatment of depression, exhibited upgrading and significant protective effects on the trauma of PC12 cells induced by 200 microM H2O2 in a dose-dependent manner within 24-hour treatment. Cell viability was assessed by the MTT method, and in situ cellular hydrogen peroxide (H2O2)-induced oxidative stress was examined by measurement of reactive oxygen species (ROS) formation using CDCFH procedures. Intra- and extra-cellular ROS levels decreased significantly to 71.9% and 50.0% of the control at a moderate concentration of 20 microg/ml, respectively, suggesting that SEHP could easily enter the cells and play important roles in reducing ROS levels. Our results were proved by detection of DNA fragmentation and inspection of cell morphology of PC12 cells. SEHP can obviously block DNA fragmentation and prevent the cells from shrinking and turning round of H2O2-induced apoptosis in PC12 cells at concentrations of 10 approximately 100 microg/ml. This data suggests SEHP may be a candidate for application in neurodegenerative diseases such as Alzheimer's disease or Parkinson's disease.

Animals↗
PubMed2004

[Patch size distribution pattern and its hierarchical effect of main landscape types in the Wuyishan scenery district].

Based on the principles of landscape ecology and community ecology, the Wuyishan district was classified into 10 landscape types, and the patch size distribution of this district was characterized by six types of probability distribution, including normal, lognormal, Weibull, Gamma, Beta and negative exponential. The results showed that most of patch types could be characterized by lognormal distribution, a few of them could be characterized by Gamma or Weibull distribution. Normal distribution was not suitable to characterize the patch size distribution. For the same type of landscape, its patch size distribution was not the same under three different classifications, which meant that there was a hierarchical effect in the distribution pattern of patch size. Among the three classifications, the distribution characteristics of patch sizes could be better revealed by the second classification(b). For different types of landscape, the distribution of patch sizes were different. None of the six probability distributions could characterize the patch size distribution of all the types of landscape or the whole scenery district. The new patch collective, which was composed of the two landscape types, would keep the pattern if the two different landscape types had the same distribution pattern of patch sizes, otherwise, its distribution would change if the patch sizes distribution of the two landscape types were different.

China↗
PubMed2004

[Modification and its application of generalized Schumacher model].

Based on the concrete analysis on growth equations presented by others, a modified Schumacher growth equation was proposed as, which included Gompertz function, Schumacher equation and generalized Schumacher equation, and had stronger self-adaptability and practicality. The analytic character and adaptability of the modified Schumacher equation were analyzed. According to the genetic algorithms method, this model was used to fit the growth data of endangered plant of Tsuga longibracteata and Platycladus orientalis. The results showed that the modified Schumacher equation was not only better than Schumacher equation and generalized Schumacher equation significantly, but also better than classical Logistic model and Li's self-adaptive model. So it could be used to study the dynamics simulation for tree growth and dynamics law for population growth.

Logistic Models↗
PubMed2004

[Life table and spectral analysis of endangered plant Taxus chinensis var. mairei population].

Based on the investigation in Longxi Mountain National Nature Reserve and the theory of survival analysis, a static life table of Taxus chinensis var. mairei population was worked out, the curves of its survival rate, mortality rate and killing power were drawn, and the population dynamics was analyzed by spectral analysis. The results showed that the survival curve of the population appeared to be a type of Deevey-III, and the high mortality of seeding was one of the important reasons which caused Taxus chinensis var. mairei to be endangered. The spectral analysis of the population showed that there was a marked periodic regularity in the process of natural regeneration of Taxus chinensis var. mairei.

China↗
PubMed2004

[Gaps and their natural disturbance characteristics in mid-subtropical evergreen broad-leaved forest in Wanmulin].

Through field investigation on 96 gaps in some permanent plots of mid-subtropical evergreen broad-leaved forest in Wanmulin Natural Reserve of Fujian Province, this paper dealt with the gap characteristics and their natural disturbance. The results showed that the area percentage of expanded gap (EG) and canopy gap (CG) in the forest landscape was 50.86% and 16.66%, and the natural disturbance frequency for EG and CG was 0.85% x yr(-1) and 0.28% x yr(-1), respectively. The return interval of canopy gaps was about 357 years. The most popular manner of gap formation in the forest was stem breakage (58.04% of the total), and the second was uprooting (33.48%). Most gaps were formed by two trees, averaging 2.33 trees per gap. The size of most expanded gaps was in the range of 100 - 300m2, the gaps of 200 - 300m2 occupied the biggest percentage in area, and those of 100 - 200m2 occupied the biggest percentage in number. The size of most canopy gaps was under 100m2, and the gaps of < 50m2 had the biggest percentage in area and number. The diameter at breast height of most gap makers was 20 - 30cm.

Altitude↗
PubMed2003

Synthesis, resolution, and applications of 1,16-dihydroxytetraphenylene as a novel building block in molecular recognition and assembly.

This paper concerns the synthesis of 1,16-dihydroxytetraphenylene (DHTP) (2) by employing a novel NBS bromination route. (+/-)-DHTP 2 was successfully resolved into its optical antipodes and converted to (+/-)-1,16-bis(diphenylphosphino)tetraphenylene (BPTP) (26), whose platinum complex BPTP-PtCl(2) (27) was also obtained. As a hydrogen bond donor, racemic and optically active DHTP 2 was allowed to assemble with 4,4'-bipyridine to form single crystals of good quality. X-ray Diffraction studies of these crystals revealed that the crystallographic packing of the hydrogen bonded complex between (+/-)-2 and 4,4'-bipyridine was different from the one formed from (S)-2 and 4,4'-bipyridine. It was found that an infinite zigzag chain with alternate chirality was formed in the assembly of (+/-)-2 and 4,4'-bipyridine, while (S)-2 and 4,4'-bipyridine failed to show the same assembly pattern. The reason (+/-)-2 formed an alternate and zigzag chain with 4,4'-bipyridine was most likely due to the inherent stability of this supramolecular assembly. The chiral recognition between 2 and optically active BINAP under the direction of platinum(II) has also been examined. (1)H and (31)P NMR spectroscopic studies demonstrated that there was an obvious discrimination of 2 between the enantiomers of BINAP-PtCO(3).

Journal Article↗
PubMed2003

Stereoselective synthesis of functionalized pyrrolidines by ruthenium porphyrin-catalyzed decomposition of alpha-diazo esters and cascade azomethine ylide formation/1,3-dipolar cycloaddition reactions.

[reaction: see text] Ruthenium porphyrins catalyze three-component coupling reaction of alpha-diazo esters with a series of N-benzylidene imines and alkenes to form functionalized pyrrolidines in excellent diastereoselectivities. The reaction proceeds via a reactive ruthenium-carbene intermediate and its subsequent reaction with imine to generate azomethine ylide, which reacts with alkenes via 1,3-diploar cycloaddition.

Journal Article↗
PubMed2003

Structural studies of the interaction of S-adenosylmethionine with the [4Fe-4S] clusters in biotin synthase and pyruvate formate-lyase activating enzyme.

The diverse reactions catalyzed by the radical-SAM superfamily of enzymes are thought to proceed via a set of common mechanistic steps, key among which is the reductive cleavage of S-adenosyl-L-methionine (SAM) by a reduced [4Fe-4S] cluster to generate an intermediate deoxyadenosyl radical. A number of spectroscopic studies have provided evidence that SAM interacts directly with the [4Fe-4S] clusters in several of the radical-SAM enzymes; however, the molecular mechanism for the reductive cleavage has yet to be elucidated. Selenium X-ray absorption spectroscopy (Se-XAS) was used previously to provide evidence for a close interaction between the Se atom of selenomethionine (a cleavage product of Se-SAM) and an Fe atom of the [4Fe-4S] cluster of lysine-2,3-aminomutase (KAM). Here, we utilize the same approach to investigate the possibility of a similar interaction in pyruvate formate-lyase activating enzyme (PFL-AE) and biotin synthase (BioB), two additional members of the radical-SAM superfamily. The results show that the latter two enzymes do not exhibit the same Fe-Se interaction as was observed in KAM, indicating that the methionine product of reductive cleavage of SAM does not occupy a well-defined site close to the cluster in PFL-AE and BioB. These results are interpreted in terms of the differences among these enzymes in their use of SAM as either a cofactor or a substrate.

Acetyltransferases↗
PubMed2003

Fungal infection in organ transplant patients.

PURPOSE: To review the characteristics and evolution of the fungal spectrum, and the risk factors causing fungal infection, and to make progress in diagnosing fungal infection after organ transplantation. DATA SOURCES: An English-language literature search (MEDLINE 1990 - 2000) and bibliographic review of textbooks and review articles. STUDY SELECTION: Twenty-three articles were selected from the literature that specifically addressed the stated purpose. RESULTS: Fungal infections in organ transplant patients were generally divided into two types: (1) disseminated primary or reactivation infection with one of the geographically restricted systemic mycoses; (2) opportunistic infection by fungal species that rarely cause invasive infection in normal hosts. The risk factors of fungal infection after a transplant can be evaluated and predicted according to the organ recipient's conditions before, during and after the transplant. Progress in early diagnostic methods during the past 10 years has mainly revolved around two aspects, culture and non-culture. CONCLUSIONS: It is important to undertake a systemic evaluation on the condition of the organ recipient before, during and after a transplant; should any risk factor for fungal infection be suspected, diagnosis should be made as early as possible by employing mycological techniques including culture and non-culture methods.

Humans↗
PubMed2003

[The clinical features and prognosis of Aeromonas septicaemia in hepatic cirrhosis: a report of 50 cases].

OBJECTIVE: Aeromonas septicaemia complicating cirrhosis is not a common infectious disease. To enhance the knowledge in this aspect, we analysed the clinical features, pathogenetic factors, resistance, treatment and prognosis of Aeromonas septicaemia in 50 cases of hepatic cirrhosis. METHODS: We cultured the bacteria from infected patients with BacT/Alert120 automation instrument made in AKsu and identified the bacteria with the Vitek-AMS60 made in Biomerieux company. We then tested the susceptibility of Aeromonas to 13 antimicrobial agents. RESULTS: A total of 50 cases of Aeromonas septicaemia occurred in severe hepatic cirrhosis. The majority of them had severe complications. Aeromonas hydrophila was the most common species isolated (52.0%). Nosocomial infection was the predominant way of infection. The major clinical manifestations of Aeromonas septicaemia were fever (100%), chill (64.0%), abdominal pain (60.0%), diarrhoea (32.0%) and shock (24.0%). The susceptive rate of Aeromonas to third generation cephalosporin, quinolones and aminoglycoside antibiotics was more than 80%. The cure rate and mortality attributed to Aeromonas septicaemia after treating with third generation cephalosporin, levofloxacin and their combination were 64.3%, 75.0%, 57.1% and 28.6%, 12.5%, 35.7% respectively. CONCLUSION: Aeromonas septicaemia tends to befall patients with severe hepatic cirrhosis and causes a rapidly fatal outcome. Aeromonas should be considered an important pathogen for septicemia in patients with liver cirrhosis. It is suggested that we should emphasize the clinical features and laboratory diagnosis so as to have proper antimicrobial treatment.

Adult↗
PubMed2003

[Gap edge effect of Castanopsis kawakamii community].

This paper reported the characters of gap edge effect of Castanopsis kawakamii community in Sanming, Fujian Province. The species diversity, ecological dominance, and edge effect strength of 38 forest gaps with different development stages in different stands of Castanopsis kawakamii community were measured, and Shannon-Wiener index, Simpson index, and index of edge effect strength were calculated. The results showed that the index of the gap edge effect of Castanopsis kawakamii community was about 0.7-1.3 (according to the species diversity index) and 0.3-1.8 (according to the ecological dominance index). The gap edge effect had the trend of increasing the species diversity of forest communities. The index of gap effect was affected by the size and development stage of the gap and the related forest type. The study provided a theoretical basis for the maintenance of species diversity and the forest management in Castanopsis kawakamii community.

Conservation of Natural Resources↗
PubMed2003

[Height structures of dominant species of different subtropical evergreen broadleaved forest communities in Wanmulin Natural Reserve].

Based on the data of four subtropical evergreen broadleaved forest communities in Wanmulin Natural Reserve, whose dominant species were Tsoongiodendron odorum Chun, Cinnamomum micranthum Hayata, Castanopsis fabri Hance and Pinus massoniana, respectively, the height class and diameter class structures and the dynamics of height structure were analyzed. The results showed that the relationships between tree species, tree density, basal area at D. B. H, and height class (or diameter class) could be simulated by different equations. There was a significant positive correlation between tree species and tree density for different height class or different D. B. H. class. The structure dynamic analysis showed that the community of Tsoongiodendron odorum Chun was very unstable, and the species sharing degree in four communities was fairly lower, indicating that the dominant species were very obvious. The results could give a useful clue for the studies on endangered mechanism of rare species.

Conservation of Natural Resources↗
PubMed2003

[Changes of blood cells in patients with severe acute respiratory syndrome].

OBJECTIVE: To investigate the changes of blood corpuscles of patients with severe acute respiratory syndrome (SARS) in Beijing. METHODS: Totally 43 patients (21 male and 22 female, 19-74 years old age range) diagnosed as of probable SARS were included in this study. Their corpuscles in the peripheral blood were tested every two days, and the results were analyzed. RESULTS: Patients with SARS were more likely to develop leukocytopenia, lymphopenia and thrombocytopenia in the early period of disease than those in control group. The situation, especially lymphopenia and thrombocytopenia, could not be reversed in patients who died. Persistent low counts of lymphocytes and platelets at presentation might be associated with adverse outcomes. CONCLUSION: Low counts of leukocytes, lymphocytes and platelets were common among patients in the early stage of SARS. Persistent Lymphopenia and thrombocytopenia may be associated with the prognosis.

Adult↗
PubMed2002

An abundant erythroid protein that stabilizes free alpha-haemoglobin.

The development of red blood cells (erythrocytes) is distinguished by high-level production of the oxygen carrier, haemoglobin A (HbA), a heterotetramer of alpha- and beta-haemoglobin subunits. HbA synthesis is coordinated to minimize the accumulation of free subunits that form cytotoxic precipitates. Molecular chaperones that regulate globin subunit stability, folding or assembly have been proposed to exist but have never been identified. Here we identify a protein stabilizing free alpha-haemoglobin by using a screen for genes induced by the essential erythroid transcription factor GATA-1 (refs 4, 5). Alpha Haemoglobin Stabilizing Protein (AHSP) is an abundant, erythroid-specific protein that forms a stable complex with free alpha-haemoglobin but not with beta-haemoglobin or haemoglobin A (alpha(2)beta(2)). Moreover, AHSP specifically protects free alpha-haemoglobin from precipitation in solution and in live cells. AHSP-gene-ablated mice exhibit reticulocytosis and abnormal erythrocyte morphology with intracellular inclusion bodies that stain positively for denatured haemoglobins. Hence, AHSP is required for normal erythropoiesis, probably acting to block the deleterious effects of free alpha-haemoglobin precipitation. Accordingly, AHSP gene dosage is predicted to modulate pathological states of alpha-haemoglobin excess, such as beta-thalassaemia.

Animals↗
PubMed2002

Electron-nuclear double resonance spectroscopic evidence that S-adenosylmethionine binds in contact with the catalytically active [4Fe-4S](+) cluster of pyruvate formate-lyase activating enzyme.

Pyruvate formate-lyase activating enzyme (PFL-AE) is a representative member of an emerging family of enzymes that utilize iron-sulfur clusters and S-adenosylmethionine (AdoMet) to initiate radical catalysis. Although these enzymes have diverse functions, evidence is emerging that they operate by a common mechanism in which a [4Fe-4S](+) interacts with AdoMet to generate a 5'-deoxyadenosyl radical intermediate. To date, however, it has been unclear whether the iron-sulfur cluster is a simple electron-transfer center or whether it participates directly in the radical generation chemistry. Here we utilize electron paramagnetic resonance (EPR) and pulsed 35 GHz electron-nuclear double resonance (ENDOR) spectroscopy to address this question. EPR spectroscopy reveals a dramatic effect of AdoMet on the EPR spectrum of the [4Fe-4S](+) of PFL-AE, changing it from rhombic (g = 2.02, 1.94, 1.88) to nearly axial (g = 2.01, 1.88, 1.87). (2)H and (13)C ENDOR spectroscopy was performed on [4Fe-4S](+)-PFL-AE (S = (1)/(2)) in the presence of AdoMet labeled at the methyl position with either (2)H or (13)C (denoted [1+/AdoMet]). The observation of a substantial (2)H coupling of approximately 1 MHz ( approximately 6-7 MHz for (1)H), as well as hyperfine-split signals from the (13)C, manifestly require that AdoMet lie close to the cluster. (2)H and (13)C ENDOR data were also obtained for the interaction of AdoMet with the diamagnetic [4Fe-4S](2+) state of PFL-AE, which is visualized through cryoreduction of the frozen [4Fe-4S](2+)/AdoMet complex to form the reduced state (denoted [2+/AdoMet](red)) trapped in the structure of the oxidized state. (2)H and (13)C ENDOR spectra for [2+/AdoMet](red) are essentially identical to those obtained for the [1+/AdoMet] samples, showing that the cofactor binds in the same geometry to both the 1+ and 2+ states of PFL-AE. Analysis of 2D field-frequency (13)C ENDOR data reveals an isotropic hyperfine contribution, which requires that AdoMet lie in contact with the cluster, weakly interacting with it through an incipient bond/antibond. From the anisotropic hyperfine contributions for the (2)H and (13)C ENDOR, we have estimated the distance from the closest methyl proton of AdoMet to the closest iron of the cluster to be approximately 3.0-3.8 A, while the distance from the methyl carbon to the nearest iron is approximately 4-5 A. We have used this information to construct a model for the interaction of AdoMet with the [4Fe-4S](2+/+) cluster of PFL-AE and have proposed a mechanism for radical generation that is consistent with these results.

Acetyltransferases↗
PubMed2002

Inhibition of CBP-mediated protein acetylation by the Ets family oncoprotein PU.1.

Aberrant expression of PU.1 inhibits erythroid cell differentiation and contributes to the formation of murine erythroleukemias (MEL). The molecular mechanism by which this occurs is poorly understood. Here we show that PU.1 specifically and efficiently inhibits CBP-mediated acetylation of several nuclear proteins, including the hematopoietic transcription factors GATA-1, NF-E2, and erythroid Krüppel-like factor. In addition, PU.1 blocks acetylation of histones and interferes with acetylation-dependent transcriptional events. CBP acetyltransferase activity increases during MEL cell differentiation as PU.1 levels decline and is inhibited by sustained PU.1 expression. Finally, PU.1 inhibits the differentiation-associated increase in histone acetylation at an erythroid-specific gene locus in vivo. Together, these findings suggest that aberrant expression of PU.1 and possibly other members of the Ets family of oncoproteins subverts normal cellular differentiation in part by inhibiting the acetylation of critical nuclear factors involved in balancing cellular proliferation and maturation.

3T3 Cells↗
PubMed2002

Physical and functional interaction between the transcriptional cofactor CBP and the KH domain protein Sam68.

CBP is a multifunctional transcriptional cofactor with tumor suppressor activity. The CH3 domain of CBP binds numerous transcription factors and several viral oncoproteins. We identified the Src substrate and RNA-binding protein Sam68 as novel CH3-binding protein. Sam68 binds the CH3 domain in part through a conserved FXD/EXXXL motif that is shared among several CH3-binding proteins, including the adenoviral oncoprotein E1A and the tumor suppressor p53. Sam68 and CBP interact in vivo and colocalize in nuclear sub-domains. Sam68 has potent transcriptional repression activity that is independent of its RNA binding activity, which suggests that RNA processing and regulation of gene expression by Sam68 are separable functions. Consistent with this, CBP did not stimulate the ability of Sam68 to promote Rev response element-containing mRNA export. Interestingly, Sam68 can regulate RNA processing in the absence of a Rev response element, suggesting that Sam68 functions through a novel RNA element. Together, these findings reveal a previously unidentified function for Sam68 as a transcriptional repressor and suggest that Sam68 might link cellular signaling pathways with components of the transcriptional machinery.

3T3 Cells↗