Biomedical subjects

X Hu

Publications and source records attributed to X Hu.

At least 91 records · Page 5Linked to original sources

PubMed2001

Upregulation of cellular retinoic acid-binding protein I expression by ethanol.

Acute and chronic ethanol ingestion cause embryopathy similar to that of hyper- or hypovitaminosis A. Experimental data have suggested interaction between vitamin A and alcohol signaling pathways at the level of metabolic interference, which ultimately affects the concentration of retinoic acid (RA) in animals. The present study was set up to examine the possible effects of alcohol on cellular RA binding protein I (CRABP-I) expression during embryonic development by using transgenic mouse embryos and P19 embryonal carcinoma cells as experimental models. It was found that expression of the mouse CRABP-I gene was elevated in developing embryos at mid-gestation stages as a result of ethanol consumption by the mothers. Specific elevation of this gene was detected in the limb bud and the gut. In the P19 model, the CRABP-I gene was directly upregulated by ethanol, which was not blocked by a protein synthesis inhibitor. Furthermore, the regulation of the CRABP-I gene by ethanol was mediated by the 5' upstream regulatory region of the CRABP-I gene promoter. A potential interaction of vitamin A and ethanol at the level of CRABP-I gene expression is discussed.

Animals↗

PubMed2001

Interleukin-10 inhibits ischemic and cisplatin-induced acute renal injury.

BACKGROUND: Acute renal failure (ARF) is caused by ischemic and nephrotoxic insults acting alone or in combination. Anti-inflammatory agents have been shown to decrease renal ischemia-reperfusion and cisplatin-induced injury and leukocyte infiltration. Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine that inhibits inflammatory and cytotoxic pathways implicated in acute renal injury. Therefore, we sought to determine if IL-10 inhibits acute renal injury. METHODS: The effects of IL-10 were studied in mice following cisplatin administration and bilateral renal ischemia-reperfusion, in a rat model of renal transplantation, and in cultured mouse cortical tubule cells. RESULTS: IL-10 significantly decreased renal injury following cisplatin administration and following renal ischemia/reperfusion. Delay of IL-10 treatment for one hour after cisplatin also significantly inhibited renal damage. IL-10 and alpha-melanocyte stimulating hormone (alpha-MSH) increased recovery following transplantation of a kidney subjected to warm ischemia. To explore the mechanism of action of IL-10, its effects were measured on mediators of leukocyte trafficking and inducible nitric oxide synthase (NOS-II). IL-10 inhibited cisplatin and ischemia-induced increases in mRNA for tumor necrosis factor-alpha (TNF-alpha), intercellular adhesion molecule-1 (ICAM-1), and NOS-II. IL-10 also inhibited staining for markers of apoptosis and cell cycle activity following cisplatin administration, and nitric oxide production in cultured mouse cortical tubules. CONCLUSIONS: IL-10 protects against renal ischemic and cisplatin-induced injury. IL-10 may act, in part, by inhibiting the maladaptive activation of genes that cause leukocyte activation and adhesion, and induction of iNOS.

Animals↗

PubMed2001

HPV-related cancer susceptibility and p53 codon 72 polymorphism.

Conflicting results regarding the association of a polymorphism at codon 72 of the p53 tumour suppressor gene and susceptibility to develop human papilloma virus (HPV)-associated cervical cancer have been published over the last year, implicating differences in ethnic background, sample origin, sample size and/or detection assay. The material for this study was collected in the identical geographical region as for 2 previous reports with contradictory results regarding the association of codon 72 genotype with squamous cell cancer (SCC). We have used an alternative detection assay, based on pyrosequencing technology, that interrogates the variable position by the accuracy of DNA polymerase. In addition to cervical clinical specimens from SCC, HPV16- and HPV18-infected adenocarcinoma cases as well as cervical intraepithelial neoplasia (CIN) were investigated. No significant association was found between p53 codon 72 genotype and the risk to develop adenocarcinoma, SCC or CIN in the Swedish population.

Adenocarcinoma↗

PubMed2001

HveC (nectin-1) is expressed at high levels in sensory neurons, but not in motor neurons, of the rat peripheral nervous system.

The entry of herpes simplex virus (HSV)-1 into cells is a complex process mediated in part by the binding of the HSV glycoprotein D (gD) to a specific cellular receptor identified as HveC, or nectin-1. We examined the distribution of HveC in sensory and motor neurons of the peripheral nervous system (PNS) by immunocytochemistry. HveC is expressed at high levels in sensory neurons of dorsal root ganglion and their peripheral axons, at lower levels in motor neurons of spinal cord, and without detectable expression in motor nerve terminals at the neuromuscular junction. These results have implications regarding the tropism of HSV to specific neuronal populations, and for the construction of HSV-based vectors for the peripheral nervous system.

Animals↗

PubMed2001

Transforming growth factor: signal transduction pathways, cell cycle mediation, and effects on hematopoiesis.

Transforming growth factor-beta (TGF-beta) is a potent growth inhibitor of various cell types including hematopoietic cells. Two receptors, TGFbetaRI and TGFbetaRII, govern the interaction between the cell and the TGF-beta ligand. Primary binding of the ligand occurs with the RII receptor, promoting formation of a heterodimer with RI and activation of signaling. This induces transient association of Smad proteins with the receptors. Smad 3 and 4 may be involved in the TGF-beta-induced G(1) arrest. TGF-beta(1) down-regulates G(1) and G(2) cyclin-dependent kinases (cdks) and cyclins in terms of both kinase activity and protein amount. TGF- beta (1) also inhibits phosphorylation of the product of the retinoblastoma tumor suppressor gene (pRb) at multiple serine and threonine residues in human myeloid leukemia cells. The underphosphorylated pRb associates with transcription factor E2F-4 in G(1) phase, whereas the phosphorylated pRb mainly binds to E2F-1 and E2F-3. Because TGF-beta(1) up-regulates p130(pRb family member)/E2F-4 complex formation and down-regulates p107(pRb family member)/E2F-4 complex formation, with E2F-4 levels remaining constant, these results suggest that E2F-4 is switched from p107 to pRb and p130 when cells exit from the cell cycle and arrest in G(1) by the action of TGF-beta(1). The "cdk inhibitor" p27 is both a positive and a negative regulator of TGF-beta(1)-mediated cell cycle control. Although TGF-beta(1) has been reported to be a selected inhibitor of normal primitive hematopoietic stem cells, TGF-beta inhibits both primitive and more differentiated myeloid leukemia cell lines.

Cell Cycle↗

PubMed2001

Apoptosis induced in rats by 4-vinylcyclohexene diepoxide is associated with activation of the caspase cascades.

Previous studies have shown that ovotoxicity induced in rats by dosing with 4-vinylcyclohexene diepoxide (VCD) is likely via acceleration of the normal rate of atresia (apoptosis). The present study was designed to investigate the apoptosis-related caspase cascades as a component of this phenomenon in isolated ovarian small follicles. Female F344 rats were given a single dose of VCD (80 mg/kg, i.p., on Day 1; a time when ovotoxicity has not been initiated), or dosed daily for 15 days (80 mg/kg, i.p., on Day 15; a time when significant ovotoxicity is underway). Ovaries were collected after the final dose. Small preantral follicles (25-100 microm in diameter) were isolated, cellular fractions were prepared, and cleavage activity or protein expression levels of caspases-3, -8, and -9 were measured. Cytosolic caspase-3 activity was increased in small follicles (P < 0.01) by VCD treatment (Day 1, 2.86 +/- 0.23; Day 15, 3.25 +/- 0.64, VCD/control, n = 3). This activation was not seen in large or antral follicles (not targeted by VCD). Procaspase-3 protein was increased(P < 0.05) by VCD treatment 212% over controls in small ovarian follicles in Day 15, but not Day 1-dosed rats. Immunofluorescence staining intensity was evaluated by confocal microscopy. Caspase-3 protein, located in the cytosolic compartment of oocytes and granulosa cells of preantral follicles in various stages of development, was selectively increased (P < 0.05) in primordial and small primary follicles from Day 15 VCD-dosed rats. Caspase-8 activity was increased in small follicles in Day 15, but not in Day 1-treated rats; whereas caspase-9 activity was increased by VCD on Day 1 in the mitochondrial fraction. Thus, these data provide evidence that accelerated atresia induced in small ovarian follicles in rats by VCD is associated with activation of a caspase-mediated cascade.

Animals↗

PubMed2001

Expression and redistribution of cellular Bad, Bax, and Bcl-X(L) protein is associated with VCD-induced ovotoxicity in rats.

Previous studies have shown that 4-vinylcyclohexene diepoxide (VCD)-induced ovotoxicity in rats is likely caused by acceleration of the normal rate of atresia (apoptosis). VCD-induced ovotoxicity is specific for small preantral follicles and is associated with increased activity of caspase cascades. The present study was designed to investigate the alteration of expression and distribution of several Bcl-2 family member proteins induced by dosing of VCD in rat small ovarian follicles. Female F344 rats were given a single dose of VCD (80 mg/kg, i.p., 1 day; a time when ovotoxicity is not initiated), or dosed daily for 15 days (80 mg/kg, i.p., 15 days; a time when significant ovotoxicity is underway). Four hours following the final dose, livers and ovaries were collected. Ovarian small (25-100 microm) and large (100-250 microm) preantral follicles were isolated, and subcellular fractions (cytosolic and mitochondrial) were prepared. Compared with controls, levels of the proapoptotic protein, Bad, were greater in both cytosolic and mitochondrial fractions of small preantral follicles collected from 15-day VCD-treated rats (cytosol, 1.97 +/- 0.16; mitochondria, 2.20 +/- 0.24, VCD/control, P < 0.05). After 15 days of daily VCD dosing, total cellular antiapoptotic Bcl-x(L) protein levels were unaffected in small preantral follicles, but its distribution in mitochondrial and cytosolic components was altered (mitochondria, 0.635 +/- 0.08; cytosol, 1.39 +/- 0.14, VCD/control, P < 0.05). Likewise, VCD did not affect protein levels of proapoptotic Bax in small follicles on Day 15. However, consistent with a Bax-mediated mechanism of apoptosis, the relative ratio of Bax/Bcl-x(L) in the mitochondrial fraction of small preantral follicles was significantly increased by VCD dosing (1.62 +/- 0.21, VCD/control, P < 0.05). Immunofluorescence staining intensity evaluated by confocal microscopy visualized cytochrome c protein in the cytosolic compartment in granulosa cells of preantral follicles in various stages of development. Relative to controls, within the population of small preantral follicles, staining intensity was less (P < 0.05) and presumably more diffuse, specifically in stage 1 primary follicles from VCD-treated animals (15 days). VCD caused none of these effects in large preantral follicles or liver (not targeted by VCD). These data provide evidence that the apoptosis induced by VCD in ovarian small preantral follicles of rats is associated with increased expression of Bad protein, redistribution of Bcl-x(L) protein and cytochrome c from the mitochondria to the cytosolic compartment, and an increase in the Bax/Bcl-x(L) ratio in the mitochondria. These observations are consistent with the involvement of Bcl-2 gene family members in VCD-induced acceleration of atresia.

Animals↗

PubMed2001

The effect of hypothermia on isoflurane MAC in children.

BACKGROUND: Hypothermia has been shown to decrease the requirement for inhaled anesthetics in animals, but information in humans is limited. METHODS: Thirty-three unpremedicated children with congenital left-to-right shunt heart diseases undergoing open heart surgeries were assigned to one of three groups, with nasopharyngeal temperatures at the time of skin incision of 37, 34, or 31 degrees C. Anesthesia was induced and maintained with isoflurane in oxygen. End-tidal isoflurane concentration and nasopharyngeal temperature were kept at stable levels for at least 15 min before the skin incision. Isoflurane minimum alveolar concentration was determined by using the Dixon up-and-down approach. RESULTS: Isoflurane minimum alveolar concentration values were 1.69 +/- 0.14%, 1.47 +/- 0.10%, and 1.22 +/- 0.15% (mean +/- SD) at 37, 34, and 31 degrees C, respectively. CONCLUSIONS: Hypothermia decreases the isoflurane requirement in children by 5.1 degrees C.

Anesthesia, Inhalation↗

PubMed2001

Trans-(DL-isoleucinato-N,O)[tris(2-aminoethyl)amine-kappa(4)N]cobalt(III)diperchlorate..

The racemic title compound, trans-[N,N-bis(2-aminoethyl)-1,2-ethanediamine-kappa(4)N](DL-isoleucinato-N,O)cobalt(III) diperchlorate, [Co(C(6)H(18)N(4))(C(6)H(12)NO(2))](ClO(4))(2), crystallizes in the enantiomorphous space group P2(1)2(1)2(1) with Z = 12 (Z' = 3). Each of the three cations in the asymmetric unit represents a different chirality of the isoleucine ligand; two of them are R (or D) and the third is the S (or L) enantiomer. The mixture crystallizes in a so-called unbalanced crystallization, in which the cations adopt a chiral array of composition RRS or SSR, depending on the crystal selected for data collection.

Journal Article↗

PubMed2001

Structures of three cis-beta1 and three cis-beta2 isomers of [Co(trien)(aminoacidato)]2+ complexes.

The crystal structures and absolute configurations of three cis-beta(1) and three cis-beta(2) isomers of [Co(trien)(L-aminoacidato)](2+), namely beta(1)-Lambda(SSS)(lambdalambdadelta)/(lambdadeltadelta)-[Co(trien)(L-isoleucinato)](ClO(4))(2), L-isoleucinato(triethylenetetramine)cobalt(III) diperchlorate (1), beta(1)-Lambda(SRS)(lambdadeltalambda)-[Co(trien)(L-valinato)](ClO(4))(2), L-valinato(triethylenetetramine)cobalt(III) diperchlorate (2), beta(1)-Delta(RSS)(deltalambdadelta)-[Co(trien)(L-pyroglutamato)]ClO(4), L-pyroglutamato(triethylenetetramine)cobalt(III) perchlorate (3), beta(2)-Delta(RRS)(deltadeltalambda)-[Co(trien)(L-isoleucinato)]I(2).H(2)O, L-isoleucinato(triethylenetetramine)cobalt(III) diiodide monohydrate (4), beta(2)-Delta(RRS)(deltadeltalambda)-[Co(trien)(L-isoleucinato)](ClO(4))(2).2H(2)O, L-isoleucinato(triethylenetetramine)cobalt(III) diperchlorate dihydrate (5), and beta(2)-Lambda(SSS)(deltalambdalambda)[Co(trien)(L-leucinato)](ClO(4))(2).2H(2)O, L-leucinato(triethylenetetramine)cobalt(III) diperchlorate dihydrate (6), have been determined. Both beta(1) and beta(2) isomers form inter-cation hydrogen-bonding interactions through double or triple hydrogen bonds which link the cations into helices. However, the motifs of the interactions are different in beta(1) and beta(2) isomers, resulting in different packing structures. A localized hydrophobic area is observed in the packing structure of (1), a unique feature amongst these six structures. This work describes the first synthesis of the beta(1) isomer by direct reaction between amino acids and cis-alpha-[Co(trien)Cl(2)]Cl in mildly basic solution.

Journal Article↗

PubMed2001

Anisotropic 2-D and 3-D averaging of fMRI signals.

A novel method for denoising functional magnetic resonance imaging temporal signals is presented in this note. The method is based on progressively enhancing the temporal signal by means of adaptive anisotropic spatial averaging. This average is based on a new metric for comparing temporal signals corresponding to active fMRI regions. Examples are presented both for simulated and real two and three-dimensional data. The software implementing the proposed technique is publicly available for the research community.

Algorithms↗

PubMed2001

Determinants of CoRNR-dependent repression complex assembly on nuclear hormone receptors.

Ligand-dependent exchange of coactivators and corepressors is the fundamental regulator of nuclear hormone receptor (NHR) function. The interaction surfaces of coactivators and corepressors are similar but distinct enough to allow the ligand to function as a switch. Multiple NHRs share features that allow corepressor binding, and each of two distinct corepressors (N-CoR and SMRT) contains two similar CoRNR motifs that interact with NHRs. Here we report that the specificity of corepressor-NHR interaction is determined by the individual NHR interacting with specific CoRNR boxes within a preferred corepressor. First, receptors have distinct preferences for CoRNR1 versus CoRNR2. For example, the retinoic acid receptor binds CoRNR1, while RXR interacts almost exclusively with CoRNR2. Second, the NHR preference for N-CoR or SMRT is due to differences in CoRNR1 but not CoRNR2. Moreover, within a single corepressor, affinity for different NHRs is determined by distinct regions flanking CoRNR1. The highly specific determinants of NHR-corepressor interaction and preference suggest that repression is regulated by the permissibility of selected receptor-CoRNR-corepressor combinations. Interestingly, different NHR surfaces contribute to binding of CoRNR1 and CoRNR2, suggesting a model to explain corepressor binding to NHR heterodimers.

Amino Acid Sequence↗

PubMed2001

Hepatitis C virus infection and morphologic study in B lymphocytes of patient with hepatitis C.

OBJECTIVE: To study hepatitis C virus (HCV) infection in B lymphocytes of patients with hepatitis C and to establish a B cell line with HCV infection and observe the hepatitis C virus like particles. METHODS: A B lymphoblastoid cell line was established by Epstein-Barr virus induced transformation directly from peripheral blood mononuclear cells of a patient with hepatitis C. The HCV antigen and HCV RNA were detected by immunohistochemical technique. Reverse transcription-polymerase chain reaction(RT-PCR) and in situ hybridization and HCV particle were detected by electron microscopy. RESULTS: Positive HCV RNA was found in supernatants of B cell line. HCV Ag and HCV RNA were also showed positive. Electron microscopy observed HCV spherical virus like particles with a diameter of approximately 65 nm and 110 nm and the "bud mutation" of HCV in the cytoplasmic vesicles of B lymphocytes. CONCLUSIONS: HCV could infect B lymphocytes and replicate in the cell line. HCV particles are formed by "bud mutation" of HCV in the cytoplasmic vesicles of B-lymphocytes.

B-Lymphocytes↗

PubMed2001

[Characterisation of transient outward potassium current (Ito1) in hypertrophied right ventricular myocytes from children with tetralogy of Fallot].

OBJECTIVE: To investigate whether a transient outward potassium current exists in children hypertrophy ventricular myocytes and to characterize its basic electrophysiological properties. METHODS: Currents were recorded using whole-cell patch-clamp technique from enzymatically isolated ventricualr myocytes obtained from hearts of 10 patients aged 0.4-5 with tetralogy of Fallot (F4) ranging in age 0.4-5 years. RESULTS: In almost all cells studied, a Ito1 could be recorded on depolarization to between -20(-)+60 mV under conditions in which Ca2+ current was blocked. The current density is 4.7 PA/PF +/- 0.6 PA/PF at 60 mV. Its inactivation time constants under tested potential 0, 20, 40, 60 mV were 123 ms +/- 6 ms, 131 ms +/- 11 ms, 122 ms +/- 6 ms, 122 ms +/- 6 ms Half-maximal activation occurred at 4.1 mV +/- 2.8 mV. Half-maximal steady-state inactivation was -41 mV +/- 4 mV. Recovery from inactivation was voltage-dependent and the time course was 83 ms +/- 4 ms. CONCLUSION: A moderate Ca(2+)-independent transient outward K+ current is present in hypertrophied human ventricular myocytes from children with tetralogy of Fallot, its basic characteritics are similar to Ito1 observed in other species and human atria.

Child, Preschool↗

PubMed2001

[Clinical research of pasinizid on retreated sputum positive pulmonary tuberculosis in senilities].

OBJECTIVE: To observe and evaluate the effect and safety of pasinizid on treatment of the senile pulmonary tuberculosis with bacteriological positive. METHODS: 115 cases of the senile pulmonary tuberculosis with bacteriological positive were divided into therapy group(group A) and control group(group B1 and B2) randomly. Chemotherapy regimen: group A were treated by 3DZL2E/5DL2E mainly composed of pasinizid; group B1 were treated by 3HPZL2/5HL2E(abbreviated HP regimen); group B2 were treated by 3DZL2E/5DL2E(abbreviated SH regimen). RESULTS: When the chemotherapy was over, the sputum negative conversion rates were 92%, 72%, 71% in group A, group B1 and group B2 respectively. The conversion rate in group A was significantly higher than that in group B1 and group B2 (P < 0.05); focal absorption rates were 75%, 50%, 50% respectively, while the vanishing rates of cavity were 85%, 46%, 50% respectively. The rate in group A was significantly higher than that in group B1 and B2(P < 0.05); Rates of side effects were 17%, 58%, 18% respectively. The rates in group A and group B2 were apparently lower than that in group B1(P < 0.01). Bacteriological relapse rate of 2 years were 5%, 19%, 18%, respectively. The rate in group A was lower than that in group B1 and B2 (P < 0.01). CONCLUSIONS: The effect of pasinizid on senile retreated sputum positive pulmonary tuberculosis was better than HP and SH regimen. Due to its lower rates of side effects, it is recommended for clinical usage.

Aminosalicylic Acid↗

PubMed2001

[Characteristics of nitrogen and phosphorus pollution in the middle and small creeks, suburban Shanghai].

1. The middle and small creeks in suburban Shanghai were under heavy eutropic condition, with high loadings of nitrogen, phosphorus and organic pollutants. KN, TP and CODCr of the surface water of them were several times greater than the critical values of Types V, the worst level of water. 2. Spatial variations of N and P pollution were observed, as the creeks in different places accepted different types and amounts of pollutants. Affected by domestic sewage, the creeks nearby residential areas were often heavily polluted by NH4+ and P. The creeks in agricultural fields were more easily polluted by NO3- than by NH4+ and phosphorus. The creeks nearby livestock farms often witnessed sudden soaring of NH4+ and P. 3. N and P loadings of the creeks were also affected by the seasonal evolvement of ecological environment. With the increase of temperature and biomass, NH4+ and NO3- in the surface water were largely consumed and decreased as a result; while organic N and particle P increased as the enhancement of suspending biological particles. NO2- in the surface water increased with temperature as nitrifying bacteria became active. Total P and water soluble P also showed the trend of enhancement with the intensification of biological activities, however, they were also controlled by the condition of pH and DO in the water. 4. At the height of the summer, the surface and bottom water of the creeks differed in N and P loadings. NH4+, soluble P and total reactive P in the bottom water were higher than those in the surface; while NO3- and NO2- in the surface were higher than those in the bottom. Such water-quality stratification inevitably resulted from the enhancement of phytoplankton in the surface water and intensified release of NH4+ and P from the sediments. In the autumn, as-the temperature decrease, such phenomenon declined gradually.

China↗

PubMed2001

[A research of infant refraction in Kunming Municipality].

OBJECTIVE: To study the infant refraction, detect ametropia in mass screening refraction and correct the ametropia properly for the treatment and prevention of amblyopia and strabismus as early as possible. METHODS: The refraction status of 1 146 children (2 291 eyes, aged 1 month -3 years) were determined with retinoscopy after tropicamide cycloplegia. RESULTS: The results of statistics showed that 89 eyes (3.88%) had emmetropia, 2 139 eyes (93.37%) hypermetropia, 38 eyes (1.66%) myopia, 560 eyes (24.44%) astigmatism and 25 eyes (1.09%) mixed astigmatism. In cases with ametropia, most of them were mild, and 97 eyes (4.23%) were moderate and severe. Anisometropia occurred in 34 infants (2.97%), and 7 infants (11 eyes, 0.48%) had strabismus. The degree of hypermetropia decreased with the increase of age. The percentage of astigmatism decreased with the age increase (chi(2) = 7.46, P<0.01), and the degree of astigmatism also decreased with the age increase (chi(2) = 26.1l, P < 0.01). Myopia increased with the age increase (chi(2) = 4.06, P < 0.05). CONCLUSIONS: The prevention of amblyopia and strabismus in children should begin at the infant period, and the cases with moderate and severe ametropia should wear eye glasses as early as possible.

Amblyopia↗

PubMed2001

[Reconstruction of corneal stroma using tissue engineering technique].

OBJECTIVE: To reconstruct new corneal stroma in order to provide a basis for future studies on the reconstruction of cornea. METHODS: The cultured corneal stromal cell-PGA complex was grafted to the subdermis of a female balb/c nude mouse. Six weeks after grafting, the new reformed tissue was fixed for histologic examination and transmission electron microscopy (TEM). At the same time, the new deposited collagen fibril diameter was measured. RESULTS: The reconstructed corneal stromal layer was formed in a waved, crossed-web structure, which was similar to the normal corneal stroma. Cell deposited collagen fibrils were similar in diameter to those seen in normal corneal stroma. CONCLUSIONS: The corneal stroma can be reconstructed by using tissue engineering technique. The reconstructed tissue which is similar to the normal cornea in key characteristics, including morphology and histologic structure provides an ideal experimental model for corneal physiological, pathologic, toxic and drug efficient testing and for future development of the tissue for implantation.

Animals↗