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Biomedical subjects

C He

Publications and source records attributed to C He.

At least 73 records · Page 4Linked to original sources
PubMed1999

Activation of inwardly rectifying K+ channels by distinct PtdIns(4,5)P2 interactions.

Direct interactions of phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) with inwardly rectifying potassium channels are stronger with channels rendered constitutively active by binding to PtdIns(4,5)P2, such as IRK1, than with G-protein-gated channels (GIRKs). As a result, PtdIns(4,5)P2 alone can activate IRK1 but not GIRKs, which require extra gating molecules such as the beta gamma subunits of G proteins or sodium ions. Here we identify two conserved residues near the inner-membrane interface of these channels that are critical in interactions with PtdIns(4,5)P2. Between these two arginines, a conservative change of isoleucine residue 229 in GIRK4 to the corresponding leucine found in IRK1 strengthens GIRK4-PtdIns(4,5)P2 interactions, eliminating the need for extra gating molecules. A negatively charged GIRK4 residue, two positions away from the most strongly interacting arginine, mediates stimulation of channel activity by sodium by strengthening channel-PtdIns(4,5)P2 interactions. Our results provide a mechanistic framework for understanding how distinct gating mechanisms of inwardly rectifying potassium channels allow these channels to subserve their physiological roles.

Amino Acid Sequence↗
PubMed1999

Transfusion-transmitted virus infection in China: prevalence in blood donors and in patients with liver diseases.

BACKGROUND: Prevalence of transfusion-transmitted virus (TTV) infection among blood donors and in patients with liver diseases in China was studied. METHODS: DNA was extracted from serum and amplified by seminested polymerase chain reaction with reported primer sets from a conserved region of the TTV genome. RESULTS: TT Virus DNA was detected in 55 of 196 blood donors (28%); 31% (40 of 127) in the north and 22% (15 of 69) in the south. TT Virus DNA was also detected in 14 of 31 patients (45%) with non-A-non-G fulminant hepatitis and in eight of 25 patients (32%) with non-A-non-G chronic hepatitis. The rate of TTV viraemia in these patients with liver disease was comparable to that in blood donors. TT Virus DNA sequencing of 12 isolates showed that the prevalence of genotype 2 was significantly higher than that reported in Japan (66.7 vs 2.6%, P < 0.001). Furthermore, genotyping assays based on restriction fragment length polymorphism were carried out on all 88 TTV DNA-positive samples. It was found that 42 isolates (47.7%) belonged to genotype 1 and 40 (45.5%) to genotype 2. It was of particular interest that the prevalence of genotype 1 in patients with non-A-non-G fulminant hepatitis was significantly higher than that in blood donors (10/14 vs 22/55, P < 0.05). CONCLUSIONS: The data indicate that TTV infection is common in China and that the pathogenic potential of TTV toward the liver (if any) may differ between genotypes.

Adult↗
PubMed1999

BWMK1, a novel MAP kinase induced by fungal infection and mechanical wounding in rice.

The activation of the mitogen-activated protein (MAP) kinases by different environmental stresses has been previously observed in several dicot plant species. Here, we report the isolation of a novel MAP kinase in rice that is induced during infection by the blast fungus Magnaporthe grisea or upon mechanical wounding. The gene is designated as BWMK1 for blast- and wound-induced MAP kinase. The cDNA of BWMK1 was isolated from rice leaves challenged by the blast pathogen. Transcripts of the corresponding gene accumulated in rice leaves 4 h after blast inoculation and 30 min after mechanical wounding. This gene encodes a 506 amino acid protein that contains a new dual-phosphorylation activation motif TDY and about 150 unique amino acids on its C terminus. In-gel kinase activity and immunoprecipitation assays confirmed that BWMK1 is a functional MAP kinase. These results show that BWMK1 is a new member of the plant MAP kinase family and may mediate both defense and wound signaling in rice.

Amino Acid Sequence↗
PubMed1999

Pretransitional behavior above the nematic-isotropic phase transition of an auxetic trimer liquid crystal.

Static light scattering and electric field-induced Kerr measurements were performed above the nematic-isotropic phase transition of a terminal-lateral-lateral-terminal negative Poisson ratio trimer. For both measurements the inverse susceptibility was observed to be nearly linear with temperature, a result inconsistent with our previously reported Kerr data [Phys. Rev. E 58, 2041 (1998)].

Journal Article↗
PubMed1999

Dietary glycotoxins: inhibition of reactive products by aminoguanidine facilitates renal clearance and reduces tissue sequestration.

Evidence indicates that the metabolic turnover of food-derived reactive orally absorbed advanced glycation end products (AGEs) or glycotoxins (GTs) is delayed, possibly contributing to the tissue damage induced by endogenous AGEs, especially in patients with diabetes and kidney disease. The aim of this study was to explore whether pharmacologic inhibition of dietary AGE bioreactivity by aminoguanidine (AG) can improve turnover and renal excretion of these substances. Normal Sprague-Dawley rats were fed single-labeled [14C]AGE-ovalbumin, double-labeled [14C-125I]AGE-ovalbumin, or control 125I-labeled ovalbumin diet plus free [14C]glucose, with or without AG (0.2% in water). [14C]AGE- and 125I-labeled peptide-associated radioactivity (RA) were compared with AGE immunoreactivity (by enzyme-linked immunosorbent assay) in tissues, serum, and 72-h urine samples. The effect of AG on dietary AGE bioreactivity was assessed by monitoring the inhibition of covalent complex formation between fibronectin (FN) peptide fragments and serum components, after a meal of labeled dietary AGE with or without AG. The radiolabeled AGE diet produced serum absorption and urinary excretion peaks kinetically distinct from those of free [14C]glucose or [125I]ovalbumin. Some 26% of the orally absorbed AGE-ovalbumin was excreted in the urine, whereas after AG treatment, urinary excre-tion of dietary AGEs increased markedly (to >50% of absorbed). More than 60% of tissue-bound RA was found covalently deposited in kidneys and liver, whereas after treatment with AG, tissue AGE deposits were reduced to <15% of the amount found in untreated AGE-fed controls. Sera enriched for dietary GTs formed covalently linked complexes with FN, a process completely inhibitable by AG cotreatment. Amelioration of dietary GT bioreactivity by AG improves renal elimination and prevents tissue deposition of food GTs. This may afford a novel and potentially protective use of AG against excessive tissue AGE toxicity in diabetic patients with renal disease.

Animals↗
PubMed1999

[Ciliary neurotrophic factor prevents NO mediated cytotoxicity in cultured hippocampal neurons].

The effects of ciliary neurotrophic factor on nitric oxide (NO)-induced cytotoxicity were examined in primary cultures of rat hippocampal neurons. The neurotoxicity was induced by NO donors, such as sodium nitroprusside (SNP), s-nitroso-N-acetylpenicillamine (SNAP), NOS substrate, L-arginine (L-Arg) and ionomycin (a calcium ionophore). Preincubation of the cultures with ciliary neurotrophic factor (CNTF) for 24 h promoted neuronal survival and decreased the LDH efflux and the level of NO induced by ionomycin. The protective effects of CNTF against NO cytotoxicity were concentration-dependent. The above findings suggest that CNTF promotes the survival of neurons in the hippocampus by preventing NO mediated neurotoxicity.

Animals↗
PubMed1999

[Effects of NGF and CNTF on NO level in brain of burn rats].

OBJECTIVE: To investigate the injurious effects of NO to the brain and protective effect of NGF and CNTF following burn injury in rats. METHODS: Following intubation of the lateral cerebroventricle, the rats were divided into four groups:sham burn, burn, burn + NGF, burn + CNTF. The contents of NO in various parts of brain in rats with 30% TBSA third degree scald were measured. RESULTS: The contents of NO were increased in burned rats. NGF and CNTF could lower the contents of NO. CONCLUSION: The brain injury caused by burns may be associated with increase of NO. The protective effect of NGF and CNTF on the brain of burn rats may be related to lowering of NO.

Animals↗
PubMed1999

Allele loss on chromosome 9q22.2-22.3 in sporadic basal cell carcinoma in Chinese.

OBJECTIVE: To investigate the role of allele loss on chromosome 9 in the pathogenesis of basal cell carcinoma (BCC) by examining the loss of heterozygosity in sporadic basal cell carcinoma and other cutaneous tumors. METHODS: DNA samples were isolated from the tumors, the matched adjacent normal skin and the blood of patients with sporadic basal cell carcinoma (14), squamous cell carcinoma (25) and Bowen's disease (5) by phenol-chloroform extraction. In our study, we used two microsatellite markers on chromosome 9, one was locus D9S319 (9p21), and the other was D9S299 (9q22.2-22.3). After PCR was performed, the samples were electrophoresed through 5% denatured polyacrylamide gels which were dried and exposed to Fuji XR films. RESULTS: Loss of heterozygosity with D9S319 (9p21) marker was not observed in the 10 informative cases of sporadic basal cell carcinoma, 19 squamous cell carcinoma and 4 Bowen's disease. Allelic deletion of D9S299 was not seen in the 21 informative cases of squamous cell carcinoma and 4 Bowen's disease. D9S299 (9q22.2-22.3) allele loss occurred in 2 of the 10 informative cases of sporadic basal cell carcinoma, indicating that there might be a susceptible tumor suppressor gene on chromosome 9, and loss of this allele might play an important role in the development of basal cell carcinoma. Inactivation of Drosophila patch (PTCH) (MSSE gene ESS1) in BCC might be necessary, if not sufficient, for BCC carcinogenesis. CONCLUSION: Chromosome 9q22.2-22.3 may contain a putative tumor suppressor gene, and the loss of this gene may play an important role in the development of sporadic basal cell carcinoma.

Basal Cell Carcinoma↗
PubMed1999

[Lymphoscintigraphy: evaluating lymphatic spread of rectal cancer].

OBJECTIVE: To investigate lymphatic drainage of rectal and lymphatic spread of rectal cancer. METHODS: Rectal endoscopic lymphoscintigraphy was performed in 37 volunteers and 16 patients. One millilitre dextran marked with (99m)Tc was injected bilaterally into submucosa of the rectum through rectal endoscopy. 1, 2, 3 hours after the injection, rectal lymphoscintigraphy was registered with a computerized gamma camera (TOSHIBA GCA901A). RESULTS: Lymphoscintigraphy in control subjects showed upward epirectal and pararectal nodes. The average number of the nodes was 12 three hours after the injection. Compared with histological node examination in all patients operated upon for rectal cancer, rectal endoscopic lymphoscintigraphy showed a sensitivity of 97.1%, a specificity of 75.0%, an overall accuracy of 87.5%, a false positivity of 25.0%, and false negativity of 8.3%. CONCLUSION: The method is better for evaluating lymphatic spread of rectal cancer before operation.

Adult↗
PubMed1999

[Immunocyte reaction in stage III nasopharyngeal carcinoma in relation to biological findings and prognosis].

OBJECTIVE: To study the relationship between macrophages (MP), Langerhans cells (LC), T and B lymphocytes, biological behavior and prognosis of stage III nasopharyngeal carcinoma (NPC) patients. METHODS: 43 cases with stage III NPC were studied by immunohistochemical SP staining methods. RESULTS: The positive expression rates of infiltrating LC and/or MP in NPC were 41%, 65% (CD68+), 46% (lysozyme+), and were related to prognosis, but not to age, sex, metastasis to cervical lymph nodes and basi-cranial destruction and/or cranial nerve damage. In addition, infiltrating T or B cells in NPC were not related to the prognosis or biological behavior. However, when both infiltrating T lymphocytes and LC and/or MP were marked, the prognosis of these cases were better than that of those cases whose infiltrating LC and/or MP were marked but T cell infiltration was scarce. CONCLUSION: The prognosis of stage III NPC is related to LC or MP, survival is especially longer in those with marked T cell infiltration.

Adult↗
PubMed1999

[A probe in good agricultural practice for traditional Chinese drugs].

OBJECTIVE: To provide some scientific reference for the good agricultural practice (GAP) for traditional Chinese drugs (TCDs). METHOD: Based on an integrated analysis of the factors bearing on the output and quality of TCD along with a study on the possible pollution sources of TCDs, some initial idea concerning the research and scope of GAP has been outlined. RESULT AND CONCLUSION: GAP for TCDs should be designed to incorporate large-scale production bases, standardization of drug varieties, optimization of planting techniques, rationalization of harvesting and processing, establishment of famous brands for quality TCDs, pollution-free production and circulation, efficient coordination of production, supply and marketing, etc.

Drugs, Chinese Herbal↗
PubMed1999

[Ciliary neurotrophic factor in the regeneration of facial nerve].

OBJECTIVE: To study the role of CNTF in regeneration of facial nerve. METHOD: SD Rat facial nerves in temporal bones were transected and then combined end to end. In ciliary neurotrophic factor group (n = 30), lesions were covered by gelatin sponge soaked with CNTF. In control group (n = 18), lesions were covered by gelatin sponge soaked with normal saline. 2, 4, 12 weeks after the operation, both CNTF group and SAL group undergone electrophysiology test and histopathology as well as quantity analysis. RESULT: Two weeks later, both CNTF and SAL group failed in eliciting muscular excitement by stimulating facial nerve; T-test showed significant difference between the two groups(P < 0.05) about the average of myelinated axons 4 weeks later, the latency of facial muscular excitement was 7.650 +/- 2.702 ms in CNTF group and 16.080 +/- 0.162 ms in SAL group. The average number of myelinated axons was 1614 +/- 411 in experimental group and 1094 +/- 343 in control group. T-test showed significant difference between them (P < 0.05). 12 weeks later, latency of facial muscle excitement was 2.016 +/- 0.122 ms in CNTF group and 2.060 +/- 0.162 ms in SAL group. The average number of myelinated axons was 1909 +/- 332 in experimental group and 1847 +/- 422 in control group. T-test showed no significant difference between the two groups (P > 0.05). CONCLUSION: CNTF enhance facial nerve regeneration in adult SD rats.

Administration, Topical↗
PubMed1999

[Determination of 10-HDA in honeybee body by HPLC].

In the present work we found that in the honeybee body there exists an unsaturated fatty acid, trans-10-hydroxy-2-decenoic acid (10-HDA), which was known only to be present in royal jelly. We established the analytical method of 10-HDA in honeybee body by HPLC and simplified the extraction method of 10-HDA. In the optimum conditions the linear range of detection was 10-1,000 ng, the correlation coefficient was 0.9998, the recovery was 96.5%-99.2% and the detectable limit was 0.53 microgram/g.

Animals↗
PubMed1999

[Changes of biomechanical properties in goats at different times after ovariectomy].

This paper presents the changes of biomechanical properties in goats at different times after ovariectomy. 14 goats were randomly divided into three groups. These goats were ovariectomized and sacrificed at 180 days (n = 4), 360 days (n = 5) and 540 days (n = 5) after the operation. The right femur, tibia and metatarsus were taken out. The structure mechanical properties of femora were measured with the three-point bending method and those of metatarsus were measured with the compressing method. The material mechanical properties of flexure, compress and tensile strength in the compact bone specimens of femora and tibiae taken from broken ends were also measured. The results showed that the one-year group, compared with the half-year group, had all the bone geometric parameters decreased, but not statistically significant (P > 0.05); the elastic modulus of three-point bending of femora decreased by 23.27% and the others had no significant difference (P > 0.05); all the material parameters of flexurel, compress and tensile strength in compact bone specimens decreased, but only the ultimate strength of tibiae of flexure, compress and tensile strength decreased obviously (P < 0.05). The one and a half year group, compared with the one year group, had the bone density of femora and tibiae decreased, but not statistically significant (P > 0.05). All the bone geometric parameters of tibiae and the thickness of bone of femora increased (P < 0.05). The break load of three-point bending of femora increased (P < 0.05). Probably, it was related to the increase of the body weight in the one and a half year group. The elastic modulus and the ultimate strength decreased, but not statistically significant (P > 0.05). When compact bone specimens were used, the ultimate strength and elastic modulus of femora and tibiae in compress and the elastic module of tibiae in flexure decreased obviously (P < 0.05); and the others had no significant changes (P > 0.05). This study indicated that the degree of osteoporosis in ovariectomized goats increased at half a year, one year, and one and a half year postoperation, and hence suggested that the ovariectomized goat be a pretty useful big animal model of osteoporosis.

Animals↗
PubMed1998

Delayed involution of the mammary epithelium in BALB/c-p53null mice.

In mammals, weaning of neonates and subsequent milk stasis initiates removal of the secretory epithelium of the mammary gland by apoptosis. The p53 tumor suppressor gene is induced rapidly following weaning of neonates, but its role in the process of involution has not been defined. Therefore, experiments were performed to identify the cell types in which the p53 gene is expressed during involution and determine the consequences of its absence in BALB/c-p53null mice. Both p53 mRNA and protein were detected in the mammary epithelium within 48 h following weaning and resulted in an eightfold increase in levels of p21WAF1 mRNA. Induction of p21WAF1 mRNA was absent in BALB/c-p53null mice, and therefore, was shown to be p53-dependent. The BALB/c-p53null mice exhibited delayed involution of the mammary epithelium, as measured by 60% greater epithelial area compared to BALB/c-p53(wt) mice through 5 days post-weaning. The delay was transient with no differences being apparent at 7 days post-weaning. Expression of the stromal protease stromelysin-1 was unaffected by the absence of p53 suggesting that stromal responses were intact. These data demonstrate that p53 participates in the first stage of involution initiated by the epithelium itself, but does not affect the second phase during which stromal proteases are induced.

Animals↗
PubMed1998

Transgenic mice overexpressing the complement inhibitor crry as a soluble protein are protected from antibody-induced glomerular injury.

Complement receptor 1-related gene/protein y (Crry) is a potent murine membrane complement regulator that inhibits classical and alternative pathway C3 convertases. In nephrotoxic serum (NTS) nephritis, injected antibodies (Abs) bind to glomeruli, leading to complement activation and subsequent glomerular injury and albuminuria. To study the phenotypic effects of continuous complement pathway blockade, transgenic mice were created that express recombinant soluble (rs) Crry directed by the broadly active and heavy metal-inducible metallothionein-I promoter. One transgenic line expressing high levels of rsCrry was propagated. Serum rsCrry levels were 18.7 +/- 2.7 microg/ml (n = 5) at basal level and increased to 118.1 +/- 20.6 microg/ml 4 d after addition of zinc to the drinking water. By reverse transcription polymerase chain reaction (RT-PCR), transgene messenger (m)RNA was present in liver, kidney, brain, lung, and spleen, but not in heart. By in situ RT-PCR analysis of kidneys, transgene mRNA was widely expressed both in renal glomeruli and tubules. Urinary excretion of rsCrry was 113.4 +/- 22.4 microg/ml with a fractional excretion relative to creatinine of 13.2 +/- 2.7%, consistent with local renal production of rsCrry and secretion into urine. The founder and all transgene positive adult animals have remained healthy with no mortality or apparent phenotypic abnormalities, including infection or immune complex disease. To determine whether rsCrry blocked complement-mediated injury, NTS nephritis was induced by injection of NTS immunoglobulin (Ig)G, followed by an 18-h urine collection to quantitate the excretion of albumin as a measure of glomerular injury. In transgene-negative littermates (n = 15), transgene-positive animals (n = 10), and transgene-positive animals fed zinc (n = 10), albuminuria was 4,393 +/- 948, 1,783 +/- 454, and 1,057 +/- 277 microg/mg creatinine, respectively (P < 0.01 by ANOVA). Glomerular C3 was evident by immunofluorescence staining in 12/15 transgene-negative animals, but in none of the transgene-positive animals fed zinc. Thus, we have produced the first transgenic animals that overexpress a soluble C3 convertase inhibitor. rsCrry expression markedly ameliorates an Ab-induced disease model in vivo. These results support the hypothesis that continuous complement inhibition at the C3 convertase step is feasible and effective in complement-mediated injury states.

Animals↗
PubMed1998

Inhibition of complement regulation is key to the pathogenesis of active Heymann nephritis.

Crry (complement receptor 1-related protein/gene y) is a key cellular complement regulator in rodents. It is also present in Fx1A, the renal tubular preparation used to immunize rats to induce active Heymann nephritis (HN), a model of membranous nephropathy. We hypothesized that rats immunized with anti-Fx1A develop autoantibodies (auto-Abs) to Crry as well as to the megalin-containing HN antigenic complex, and that anti-Crry Abs promote the development of injury in HN by neutralizing the complement regulatory activity of Crry. Rats immunized with Fx1A lacking Crry remained free of proteinuria and glomerular deposits of C3 during a 10-wk follow-up despite typical granular immunoglobulin (Ig)G deposits in glomeruli. Anti-Fx1A auto-Abs were present in their sera at levels that were not different from sera pooled from proteinuric rats with HN induced with nephritogenic Fx1A. Passive administration of sheep anti-Crry Abs to rats immunized with Crry-deficient Fx1A led to proteinuria and glomerular C3 deposition, which were not seen in such rats injected with preimmune IgG, nor in rats with collagen-induced arthritis injected with anti-Crry IgG. To directly examine the role of Crry in HN, rats were immunized with Crry-deficient Fx1A reconstituted with rCrry. This led to typical HN, with 8 out of 15 rats developing proteinuria within 14 wk. Moreover, the extent of glomerular C3 deposition correlated with proteinuria, and anti-Crry Abs were present in glomerular eluates. Thus, Crry is a key nephritogenic immunogen in Fx1A. Formation of neutralizing auto-Abs to Crry impairs its function, leading to unrestricted complement activation by Abs reactive with the HN antigenic complex on the epithelial cell surface.

Animals↗