Biomedical subjects

C Shi

Publications and source records attributed to C Shi.

At least 19 recordsLinked to original sources

PubMed2006

Ca(v)3.1 splice variant expression during neuronal differentiation of Y-79 retinoblastoma cells.

A decrease in transient-type calcium channel current, Ca(v)3.1 protein and the mRNA encoding these channels has been reported during differentiation of human retinoblastoma cells. In this study, we examined splice variants of Ca(v)3.1 before and after neuronal differentiation of the Y-79 retinoblastoma cell line to investigate the potential contribution of Ca(v)3.1 to Y-79 differentiation. In Ca(v)3.1, alternative splicing induces variations in three cytoplasmic regions, e.g. the link between domains II and III (producing isoforms e+ and e-), the link between domains III and IV (producing isoforms a, b, ac and bc) and the carboxy terminal region (producing isoforms f and d). Our results demonstrate that Ca(v)3.1e was not expressed in either undifferentiated or differentiated retinoblastoma cells. Splice variants Ca(v)3.1ac; Ca(v)3.1bc and Ca(v)3.1b were all identified in undifferentiated retinoblastoma cells, while expression of these variants in differentiated cells was restricted to the Ca(v)3.1bc isoform. The carboxy terminal variant Ca(v)3.1f is expressed independently of the differentiation status of retinoblastoma cells with or without Ca(v)3.1d. Examination of the functional contribution of Ca(v)3.1 protein to Y-79 cell differentiation revealed that in Y-79 cells transfected with Ca(v)3.1 antisense oligodeoxynucleotides, knockdown of Ca(v)3.1 did not alter the time-course of differentiation or neuritogenesis. The changes in Ca(v)3.1 splice variants were not required for the initiation of differentiation but may be associated with tissue-specific expression or localized alterations in Ca(2+) signaling that are essential for establishment of the mature differentiated phenotype.

Alternative Splicing↗

PubMed2006

Study on energy metabolism in perioperative infants.

OBJECTIVES: To evaluate resting energy expenditure (REE) in surgical infants and define the effects of the degree of stress on its level. SUBJECTS AND METHODS: Between June 1999 and June 2003 forty-five infants awaiting surgery (boys/girls: 32/13) from the Department of Pediatric Surgery were entered in the study. Indirect calorimetry was used to measure the REE of all the patients before operation and 1 - 7 days after operation. Clinical data were collected, including age, weight, height, diagnosis, operative method, site and duration, and first day postoperative C-reactive protein (CRP) levels. RESULTS: The REE before operation did not differ significantly from the postoperative values (paired t-test, p > 0.05). The predicted REE was significantly higher than the measured REE even before and after the operation (p < 0.01). REE values in the first three postoperative days were lower in the mild stress group than in the severe surgical stress group. CONCLUSIONS: REE variation among the patients is relatively large. Changes in REE may be related to the degree of stress. Predicted REE values may be not a good reflection of measured REE.

Calorimetry↗

PubMed2004

Evaluation of coastal zone sustainability: an integrated approach applied in Shanghai Municipality and Chong Ming Island.

A systems approach has been applied to the examination of sustainable development in the coastal zone. This complex system is envisaged as comprising three sub-systems: environment and resources, economic development and society. A sustainability indicator system based on these three sub-systems has been set up to evaluate the nature of development in the coastal zone. The administrative regions of the Municipality of Shanghai and Chong Ming Island (in the Yangtze Estuary) have been selected as two coastal zones in which to demonstrate the feasibility and effectiveness of the approach. The approach indicated that the development process in Shanghai is one of weak sustainability with relatively rapid social and economic development at the cost of environment and resource degradation. In contrast, social and economic development in Chong Ming County has been limited to protect the regional environment and resources indicating a more sustainable approach to development.

Algorithms↗

PubMed2004

Identification of hematopoietic cell populations from the dermal papillae of human hair follicles.

Hematopoietic stem cell (HSC) activity has been identified from the hair follicles (HFs) in mice; however, it has not been identified in human HFs. We used immunohistochemistry and flow cytometry to identify cultured dermal papilla (DP) cells expressing CD45 to test for hematopoietic activity in colony-forming assays of granulocyte/macrophage hematopoietic progenitors (CFU-GM). Occasional CD45-positive cells were detected in cultured DP cells. After in vitro stimulation with IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) for 7 days, about 1% of the cells were CD45-positive by flow cytometry analysis, an fifty-fold expansion in cell numbers. We further examined whether mesenchymal stem/progenitor cells reside in human dermal papillae. Cultured DP papilla cells incubated with monoclonal antibodies to remove the CD45 positive cells were induced into multilineage differentiation with the formation of CFU-GM. Our findings preliminarily indicate that human dermal papilla contain at least a CD45-positive hematopoietic cell population and a mesenchymal stem/progenitor cell population.

Adult↗

PubMed2003

Characterization of a novel ranavirus isolated from grouper Epinephelus tauvina.

A large icosahedral virus was isolated from diseased grouper Epinephelus tauvina. The virus grew well in several cultured fish cell lines, with stable and high infectivity after serial passages in grouper cell line (GP). The virus was sensitive to both acid and heat treatments. Virus replication was inhibited by 5-iodo-2-deoxyuridine (IUDR), indicative of a DNA-containing genome. The virus infectivity was reduced with ether treatment, suggesting that the virus was lipid-enveloped. Electron micrographs showed abundant cytoplasmic icosahedral virons in the virus-infected GP cells. The size of the intracellular nucleocapsid was 154 nm between the opposite sides, or 176 nm between the opposite vertices with an inner electron-dense core of 93 nm. Virus particles were released through budding from plasma membranes with a size of 200 nm in diameter. SDS-PAGE of purified virus revealed 20 structural protein bands and a major capsid protein (MCP) of 49 kDa. A DNA fragment of approximately 500 nucleotides was successfully amplified by polymerase chain reaction (PCR) using the primers from conserved regions of the MCP gene of frog virus 3 (FV3), the type species of Ranavirus. Subsequent multiple alignment and phylogenetic analysis showed that the newly isolated grouper virus was closely related to largemouth bass virus (LMBV), FV3 and Regina ranavirus (RRV). Our data suggests that the virus isolate is a novel member of genus Ranavirus, family Iridoviridae. We tentatively name the virus as Singapore grouper iridovirus (SGIV). SGIV was able to cause serious systemic disease capable of killing 96% of grouper fry.

Amino Acid Sequence↗

PubMed2003

Development of sustainability indicators by communities in China: a case study of Chongming County, Shanghai.

Public participation as a means of identifying sustainability indicators for Chongming County, Shanghai, China was evaluated by an international group drawing on established best practice. An initial 'long list' of 86 sustainability indicators, based on previous indicator systems developed in China, was identified. This 'long list' was reduced via consultations with local academics and local-government officers from Shanghai City and Chongming County to a 'short list' of 17 indicators. This short-list was subjected to further community consultation involving 159 local-government officers, teachers, students (aged 12-14 years), farmers and workers. Data from the consultations indicated differences in the understanding of sustainable development among the different sectors. By combining the data from the different sectors it was possible to identify a consensus around 4 core and 7 additional indicators. These are proposed as indicators which could be used to steer local activities directed towards sustainable development. The list of indicators produced by the people of Chongming Island was compared to local indicator systems in Europe. In comparison with European lists the Chongming list was found to have a greater emphasis on economic development but a similar level of concern for environmental matters. This study has special significance as it reports on the implementation of a process involving local resident participation in the process of sustainable development in China.

Adolescent↗

PubMed2002

In vivo functional proteomics: mammalian genome annotation using CD-tagging.

A self-inactivating CD-tagging retroviral vector was used to introduce epitope and GFP tags into genes and proteins in NIH 3T3 cells. Several hundred cell clones, each expressing GFP fluorescence in a distinctive pattern, were isolated. Molecular analysis showed that a wide variety of genes and proteins, some known and some newly discovered, had been tagged. The analysis also revealed that, in the great majority of instances, the abundance and cellular location of the tagged protein mirrored that of its untagged counterpart. This approach provides a systematic means for the functional annotation of mammalian genomes and proteomes in living cells.

3T3 Cells↗

PubMed2001

Visual pathways involved in fear conditioning measured with fear-potentiated startle: behavioral and anatomic studies.

Visual pathways to the amygdala, a brain structure critical for classical fear conditioning, were investigated. Conditioned fear was measured in rats as increased acoustic startle amplitude in the presence versus absence of a light or an odor paired previously with foot shock (fear-potentiated startle). Post-training lesions of both the lateral geniculate body (LG) and lateral posterior nucleus (LP) of the thalamus together, but not lesions of LG or LP alone, completely blocked the expression of fear-potentiated startle to a visual conditioned stimulus (CS) but not to an olfactory CS. These lesions also did not block contextual fear conditioning using startle or freezing as measures. Local infusion of 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f] quinoxaline-7-sulfonamide disodium, an AMPA antagonist, into the visual thalamus immediately before testing also blocked fear-potentiated startle to a visual CS, suggesting that the lesion effects were not attributable to damage of fibers of passage. Iontophoretic injections into the LP of the anterograde tracer biotinylated dextran amine resulted in heavy anterograde labeling in two amygdala-fugal cortical areas: area TE2 and dorsal perirhinal cortex (PR), and moderate labeling in the lateral amygdaloid nucleus (L). These results suggest that, during classical fear conditioning, a visual stimulus can be transmitted to the amygdala via either lemniscal (i.e., LG --> V1, V2 --> TE2/PR) or non-lemniscal (i.e., LP --> V2, TE2/PR) thalamo-cortico-amygdala pathways, or direct thalamo-amygdala (i.e., LP --> L) projections.

Amygdala↗

PubMed2001

Leukocyte integrin Mac-1 recruits toll/interleukin-1 receptor superfamily signaling intermediates to modulate NF-kappaB activity.

The leukocyte integrin Mac-1 (alphaMbeta2, CD11b/CD18) regulates important cell functions in inflammation, including adhesion, phagocytosis, and oxidative burst. Deficiency of Mac-1 reduces vessel wall inflammation and neointimal thickening after murine carotid artery injury. Although Mac-1 has been implicated in modulating AP-1 and NF-kappaB activity, the signal transduction pathways involved are undefined. cDNA array analysis of Mac-1-clustered compared with -nonclustered monocytic THP-1 cells showed increased expression of the signal transducer TRAF6 (TNF receptor-associated factor 6), leading us to consider the possibility that Mac-1 used a Toll/IL-1 receptor family-like signaling pathway. Mac-1-dependent activation of NF-kappaB was potentiated by wild-type, and attenuated by dominant negative, TRAF6- and TGF-beta-activated kinase (TAK1) constructs. IRAK1 (IL-1 receptor associated kinase), a kinase immediately upstream of TRAF6, coimmunoprecipitated with Mac-1. Taken together, these observations indicate that Mac-1 recruits a Toll/IL-1 receptor family-like cascade to modulate NF-kappaB activity. This represents a new pathway for integrin-dependent modulation of gene expression.

Adaptor Proteins, Signal Transducing↗

PubMed2001

HIV gp120 V(1)/V(2) and C(2)-V(3) domains glycoprotein compatibility is required for viral replication.

The envelope gene, especially the V(3) region, of HIV-1 has been shown to be a principal determinant of cell tropism, replication and cytopathogenicity of the virus. In addition, the V(1)/V(2) region of the envelope gene has been found to be an important factor in cell tropism. We examined the compatibility between the V(1)/V(2) and C(2)-V(3) domains of HIV-1 gp120 in different combinations on viral replication by using envelope recombinants between ME1 and ME46, two infectious molecular clones with diverse biologic activity longitudinally isolated from one seropositive subject. Our data demonstrate that a proper interaction between the regions of V(1)/V(2)and C(2) is essential for viral infection and hence replication. Sequence analysis and subsequent site directed mutagenesis study indicate that the pattern of potential envelope N-glycosylation in the V(1)/V(2) and C(2)-V(3) regions may be the determining factor in such interaction between these two regions. It is possible that improper N-glycosylation sites while not affecting virus assembly, can influence through steric hindrance the conformational change of the V(3) region that is required for the co-receptor attachment and hence the viral infectivity.

Binding Sites↗

PubMed2001

Catalysis of the electro-oxidation of carbon monoxide by cobalt octaethylporphyrin.

The electro-oxidation of cobalt (II) octaethylporphyrin adsorbed on graphite electrodes, Co(II)(OEP)(ads') to Co(III)(OEP)(ads)(+), in the presence of aqueous solutions of CO leads to catalytic oxidation of CO to CO(2). No such oxidation occurs with Co(II)(OEP) and CO dissolved in nonaqueous solvents. Coordination of the CO to Co(III)(OEP)(+) is the first step in the catalytic mechanism. Nucleophilic attack on the coordinated CO by H(2)O is the probable rate-limiting step in the catalytic oxidation. A pseudo first-order rate constant of 0.3 s(-1) was estimated for this reaction.

Journal Article↗

PubMed2001

Long-term memory is facilitated by cAMP response element-binding protein overexpression in the amygdala.

At least two temporally and mechanistically distinct forms of memory are conserved across many species: short-term memory that persists minutes to hours after training and long-term memory (LTM) that persists days or longer. In general, repeated training trials presented with intervening rest intervals (spaced training) is more effective than massed training (the same number of training trials presented with no or short intervening rest intervals) in producing LTM. LTM requires de novo protein synthesis, and cAMP response element-binding protein (CREB) may be one of the transcription factors regulating the synthesis of new proteins necessary for the formation of LTM. Here we show that rats given massed fear conditioning training show no or weak LTM, as measured by fear-potentiated startle, compared with rats given the same amount of training but presented in a spaced manner. Increasing CREB levels specifically in the basolateral amygdala via viral vector-mediated gene transfer significantly increases LTM after massed fear training. The enhancing effect of CREB overexpression on LTM formation is shown to be specific in terms of biochemistry, anatomy, time course, and the training procedure used. These results suggest that CREB activity in the amygdala serves as a molecular switch for the formation of LTM in fear conditioning.

Amygdala↗

PubMed2001

Monoaminergic innervation of the macaque extended amygdala.

The extended amygdala is a group of structures including the central and medial amygdaloid nuclei, bed nucleus of the stria terminalis, and sublenticular substantia innominata. This group of structures is thought to be important in a variety of psychiatric disorders, many of which are linked in one way or another to monoamines and their transporters. However, not much is known about the distribution of these molecules in the primate extended amygdala. Thus, we mapped the distribution of fibers immunoreactive for tyrosine hydroxylase, dopamine beta-hydroxylase, serotonin, dopamine transporter, and serotonin transporter in the brains of macaque monkeys. Tyrosine hydroxylase-, serotonin-, and serotonin transporter-immunoreactive fibers were found in highest concentrations in the lateral division of the central nucleus and lateral dorsal part of the bed nucleus of the stria terminalis. Dopamine beta-hydroxylase-immunoreactive fibers were found in the highest concentration in the lateral ventral bed nucleus of the stria terminalis. Dopamine transporter-immunoreactive fibers were found in the highest concentrations in the lateral juxtacapsular and lateral dorsal capsular subnuclei of the bed nucleus and lateral capsular subnucleus of the central amygdaloid nucleus, though in much lower amounts than was present in the striatum. These results suggest prominent roles for these transmitters, particularly in the lateral dorsal bed nucleus and lateral part of the central nucleus. The relative absence of dopamine transporter in the extended amygdala suggests that this transmitter acts more through volume transmission while serotonin, which is generally accompanied by proportionate amounts of transporter, may act more like a classical neurotransmitter. In addition, the finding of heavy concentrations of dopamine- and serotonin-immunoreactive fibers in the lateral central nucleus and lateral dorsal bed nucleus lends further support to the idea of these areas as parallels in some respects to the striatum.

Acetylcholine↗

PubMed2001

The interaction of azide with polyphenol oxidase II from tobacco.

Spectroscopy studies of absorption and circular dichroism of native PPO II and azide PPO II complex demonstrate two new absorptions at 375 nm and 500 nm after azide's binding with PPO II, which are assigned as the terminal azide to copper charge transfer transitions II(o)nb-to-copper and II(v)nb-to-copper charge transfer transitions respectively. FT-IR spectra also demonstrate that the azide binds in terminal geometry with one of type-3 coppers. The interaction between azide and PPO II is discussed. One terminal azide's binding with one type-3 copper improves the activity of PPO II and the other three azides' further binding in terminal geometry with the type-3 coppers decreases the activity. We theorize that steric hindrance of azides makes oxygen difficult to bind in the active site.

Azides↗

PubMed2001

Photodynamic therapy with motexafin lutetium induces redox-sensitive apoptosis of vascular cells.

Motexafin lutetium is a photosensitizer that accumulates in atherosclerotic plaque and, after activation by far-red light, produces cytotoxic singlet oxygen. The combination of photosensitizer and illumination, known as photodynamic therapy (PDT), has been shown to reduce atheroma formation in animal models and is under clinical investigation. However, the effects of PDT with motexafin lutetium on isolated vascular cells are unknown. This study was designed to characterize the effects of PDT on vascular cell viability and to define the cell-death pathway for this agent. Fluorescence microscopy of RAW macrophages and human vascular smooth muscle cells revealed time-dependent uptake of motexafin lutetium. Illumination of motexafin lutetium-loaded cells with 732-nm light (2 J/cm(2)) impaired cellular viability and growth (IC(50) 5 to 20 micromol/L). Depletion of intracellular glutathione potentiated (P=0.035) and the addition of antioxidant N-acetylcysteine attenuated (P=0.002) cell death, suggesting that the intracellular redox state influences motexafin lutetium action. PDT was associated with the loss of mitochondrial membrane potential, mitochondrial release of cytochrome c, and caspase activation. PDT promoted phosphatidylserine externalization and induced apoptotic DNA fragmentation, with the number of apoptotic cells increasing from 7+/-2% to 34+/-3% of total cells. Reducing plaque cellularity by the induction of apoptosis may be one mechanism by which PDT reduces plaque burden, possibly modulates plaque vulnerability, and inhibits restenosis in vivo.

Animals↗

PubMed2001

[Gene dispersal risk of transgenic plants].

Gene flow is a key problem and top topic in risk assessment and management of transgenic plants. Five major study areas of gene dispersal in transgenic plants were reviewed in this paper, which include gene flow from transgenic plant to its wild species, characteristics of gene flow based on pollen, methods of doing experiment and risk assessment for gene flow, safety standards of risk assessment of transgenic plants, and long-term ecological impact of gene flow in the future. Some areas needed to be studied further were also proposed.

Ecosystem↗

PubMed2001

Hemodynamics and the focal origin of atherosclerosis: a spatial approach to endothelial structure, gene expression, and function.

Atherosclerosis originates at predictable focal and regional sites that are associated with complex flow disturbances and flow separations in large arteries. The spatial relationships associated with hemodynamic shear stress forces acting on the endothelial monolayer are considered in experiments that model regions susceptible to atherosclerosis (flow disturbance) and resistant to atherosclerosis (undisturbed flow). Flow disturbance in vitro induced differential expression at the single gene level as illustrated for the intercellular communication gene and protein, connexin 43. Transcription profiles of individual endothelial cells isolated from both disturbed and undisturbed flow regions exhibited more expression heterogeneity in disturbed than in undisturbed flow. We propose that within highly heterogeneous populations of endothelial cells located in disturbed flow regions, proatherosclerotic gene expression may occur within the range of expression profiles induced by the local hemodynamics. These may be sites of initiation of focal atherosclerosis. Mechanisms are proposed to account for heterogeneous endothelial responses to shear stress by reference to the decentralized model of endothelial mechanotransduction. Length scales ranging from centimeters to nanometers are useful in describing regional, single cell, and intracellular mechanotransduction mechanisms.

Arteriosclerosis↗

PubMed2001

[Clinical study on the efficacy of tranexamic acid in reducing postpartum blood lose: a randomized, comparative, multicenter trial].

OBJECTIVE: To study the efficacy and safety of Transamin (tranexamic acid) in reducing postpartum blood loss. METHODS: Four hundred primipara with term singleton pregnancy, vertex presentation, spontaneous delivery were enrolled. Ten U Oxytocin was injected intravenously immediately after the delivery of fetal shoulders in the second stage of labor. Then all the puerperants were randomly assigned to 4 groups. Group I (n = 94): Transamin 1.0 g was injected i.v.; Group lI (n = 92): Transamin 0.5 g i.v.; Group III (n = 92): aminomethylbenzoic acid 0.5 g i.v. was given; Group IV (n = 87): no treatment. Vaginal bleeding was precisely collected, and examined immediately after the expulsion of placenta and from placenta expulsion till 2 hours after delivery. The amount of blood loss was measured by both methods of weight and volume. RESULTS: There were no significant differences of blood loss immediately after the expulsion of placenta among the 4 groups (P > 0.05). For the average blood loss at 2 hour postpartum, it was 129.7 ml, 133.9 ml, 168.5 ml and 178.2 ml for group I, II, II and IV respectively, while the total blood loss for the 4 groups was 243.3 ml, 242.9 ml, 308.1 ml, and 314.8 ml respectively. The average blood loss of group I and II was significantly less than group III and IV (P < 0.01), however, there was no significant difference between group I and group II (P > 0.05). The occurrences of postpartum hemorrhage (blood lose > or = 400 ml) were 6.4%, 13.3%, 20.7% and 25.3% for group I, II, III and IV respectively. There was no major adverse effects appeared. CONCLUSIONS: Transamin is efficient and safe in reducing the postpartum blood loss. 1.0 g of Transamin has the best efficacy, and 0.5 g of Transamin followed.

Antifibrinolytic Agents↗