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Hong Gao

Publications and source records attributed to Hong Gao.

98 records · Page 6Linked to original sources
PubMed2002

IgA Fc receptor (FcalphaR) cross-linking recruits tyrosine kinases, phosphoinositide kinases and serine/threonine kinases to glycolipid rafts.

The human IgA Fc receptor (FcalphaR, CD89) triggers several important physiological functions, including phagocytosis, NADPH oxidase activation and antigen presentation. Efforts are underway to delineate FcalphaR signal-transduction pathways that control these functions. In a previous study, we demonstrated that cross-linking of FcalphaR increased its partitioning into membrane glycolipid rafts and was accompanied by gamma-chain-dependent recruitment and phosphorylation of the tyrosine kinases Lck/Yes-related novel protein tyrosine kinase (Lyn) and Bruton's tyrosine kinase (Btk). Here we have performed a more extensive characterization of signalling effectors recruited to rafts on FcalphaR cross-linking. We demonstrate that in addition to tyrosine kinases Lyn and Btk, FcalphaR cross-linking also recruits B-lymphocyte kinase (Blk) and spleen tyrosine kinase (Syk) to rafts. We show recruitment of phosphoinositide kinases, including 3-phosphoinositide 3-kinase and phospholipase Cgamma2, and serine/threonine kinases such as protein kinase C (PKC) alpha, PKCepsilon, and protein kinase B (PKB) alpha. This suggests that lipid rafts serve as sites for FcalphaR-triggered recruitment of multiple classes of signalling effectors. We further demonstrate that tyrosine kinases and PKCalpha have a sustained association with rafts, whereas phosphoinositide 3-kinase and its downstream effectors have a transient association with rafts. This is consistent with temporally regulated divergence of FcalphaR signalling pathways in rafts. Furthermore, we suggest the spatial separation of signalling effectors by transport of phosphoinositide 3-kinase, phosphoinositide-dependent kinase 1, PKBalpha and PKCepsilon to endocytic compartments containing internalized FcalphaR.

1-Phosphatidylinositol 4-Kinase↗
PubMed2002

Experimental observation of short-pulse upshifted frequency microwaves from a laser-created overdense plasma.

A short and frequency upshifted from a source microwave pulse is experimentally generated by the overdense plasma that is rapidly created by a laser. The source wave, whose frequency is 9 GHz, is propagating in the waveguide filled with tetrakis-dimethyl-amino-ethylene gas, which is to be converted to the overdense plasma by the laser. The detected frequency of the pulse is over 31.4 GHz and its duration is 10 ns. This technique has the potential for the generation of a tunable frequency source.

Journal Article↗
PubMed2002

PTH-dependent adenylyl cyclase activation in SaOS-2 cells: passage dependent effects on G protein interactions.

Parathyroid hormone (PTH) sensitive adenylyl cyclase activity (ACA) in SaOS-2 cells varies as a function of cell passage. In early passage (EP) cells (< 6), ACA in response to PTH and forskolin (FOR) was relatively low and equivalent, whereas in late passage (LP) cells (> 22), PTH exceeded FOR dependent ACA. Potential biochemical mechanisms for this passage dependent change in ACA were considered. In EP, prolonged exposure to pertussis toxin (PT) markedly enhanced ACA activity in response to PTH, Isoproterenol and Gpp(NH)p, whereas ACA in response to FOR was decreased. In contrast, the identical treatment of LP with PT diminished all ACA in response to PTH, Gpp(NH)p, and FOR. The dose dependent effects of PT on subsequent [(32)P]ADP-ribosylation of its substrates, GTPase activity, as well as FOR-dependent ACA, were equivalent in EP and LP. The relative amounts of G(alpha)i and G(alpha)s proteins, as determined both by Western blot, PT and cholera toxin (CT) dependent [(32)P]ADP-ribosylation, were quantitatively similar in EP and LP. Western blot levels of G(alpha)s and G(alpha)i proteins were not influenced by prior exposure to PT. Both PT and CT dependent [(32)P]ADP-ribosylation were dose-dependently decreased following exposure to PT. However, the PT-dependent decline in CT-dependent [(32)P]ADP-ribosylation occurred with enhanced sensitivity in LP. The protein synthesis inhibitor cycloheximide partially reversed the PT associated decrease in FOR dependent ACA in EP. In contrast, cycloheximide completely reversed the PT associated decrease in FOR and as well as PTH dependent ACA in LP. G(alpha)s activity, revealed by cyc(-) reconstitution, was not altered either by cell passage or exposure to PT. The results suggest that the coupling between the components of the complex may be pivotally important in the differential responsiveness of early and late passage SaOS-2 cells to PTH.

Adenylate Cyclase Toxin↗
PubMed2002

[Levels and clinical significance of CD44 (intron 9) and CD44v6 in malignant cerebroma].

OBJECTIVE: To investigate the expression of CD44 (intron 9) and CD44v6 in brain neoplasm. METHODS: CD44 (intron 9) and CD44v6 were detected in malignant meningoma, encephalic glioma, and normal encephalic tissues around the brain noeplasm respectively by using RT-PCR. RESULTS: The positive expression rate of CD44v6 was 92.86% (26/28) in malignant meningoma and 88.0% (22/25) in encephalic glioma. They were significantly higher than 5.0% (1/20) in normal encephalic tissues (P < 0.01). Mass values of malignant meningoma and encephalic glioma were higher than that of normal encephalic tissues (P < 0.01). The expression of CD44 (intron 9) was higher in malignant meningoma and encephalic glioma than in normal encephalic tissues (P < 0.01). CONCLUSIONS: Detection of CD44 (intron 9) and CD44v6 might be helpful to the diagnosis of malignant cerebroma.

Adolescent↗
PubMed2002

[Clinical and pathological characteristics of primary biliary cirrhosis].

OBJECTIVE: In order to improve the cognition and early diagnosis of primary biliary cirrhosis (PBC), we investigated clinical and pathological characteristics of PBC. METHODS: Clinical data of 37 PBC patients together with pathological findings of 20 PBC patients were reviewed. RESULTS: Among the 37 patients, 35 were women and the mean age at diagnosis was (53.4 8.9) years. The most frequent clinical presentations were jaundice (70.3%), fatigue (70.3%), and pruritus (56.8%). Serum glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP) levels were markedly elevated in all patients (P50 was 467.50 U/L and 424.00 U/L, respectively). Among the 37 cases, 35 (94.6%) had total bile acids elevation, 32 (86.5%) had serum cholesterol elevation and 32 (86.5%) serum IgM elevation, 34 (91.9%) were positive for anti-mitochondrial antibody (AMA) and/or AMA-M2. Liver biopsy in 20 PBC patients mainly found: fibrosis in 17 cases (85%), interlobular bile duct lesions in 13 (65%), lobular mononuclear inflammation in 13 (65%), lymphocytic hepatocellular piecemeal necrosis in 10 (50%), and bile pigment accumulation in 9 (45%). The results of nonparametric test showed that GGT was related with pathological stage (P=0.002) and interlobular bile duct lesions (P=0.01). CONCLUSIONS: PBC is mostly found in middle-aged women. Accurate and prompt diagnosis of PBC should be based on the clinical presentation, biochemical and immunological indexes, and hepatic pathological changes. The level of GGT may partly reflect the severity of the histological lesions

Bile Acids and Salts↗
PubMed2002

[Effects of plant foliar litter diversity on the growth of Chinese fir seedling and the absorption of (15NH4)2SO4].

Effects of plant foliar litter species composition on the growth of the potted Chinese fir seedling and the absorption of (15NH4)2SO4 was studied. The result showed that there were significant growth responses to foliar litter treatments. A very noticeable trend was that as the tree species of foliar litter placed on pots increases, the growth of Chinese fir seedlings increases steadily. Seedling growth in four-species mixed foliar litter were the largest and that in Cunninghamia lanceolata + Michelia macclurei + Kalooanax septemlobus foliar litter mixture were the second. The others were in order of seedlings in C. lanceolata + M. macclurei + Castanopsis carlesii foliar litter mixture > C. lanceolata + K. septemlobus foliar litter mixture > C. lanceolata + C. carlesii > control (no foliar litter) > C. lanceolata + M. macclurei foliar litter mixture > Chinese fir foliar litter treatment. The recovery of (15NH4)2SO4 by Chinese fir seedlings in no foliar litter treatment was maximum, and seedlings grown in four foliar litter mixture was the second, then it was in order of C. lanceolata + C. carlesii + K. septemlobus = C. lanceolata + C. carlesii + M. macclurei > C. lanceolata + K. septemlobus > C. lanceolata + C. carlesii > C. lanceolata + M. macclurei > C. lanceolata foliar litter treatment. In addition, the residue of (15NH4)2SO4 was greater in soil with foliar litter treatment than in no foliar litter soil. Both of the residual amount of (15NH4)2SO4 in soil and the total recovery of (15NH4)2SO4 increased with the increasing tree species of applied foliar litter.

Absorption↗
PubMed2002

[The theoretical calculation for optimal doping content of blood compatible titanium oxide films].

The quantitative theory of optimal doping content of transparent conductive films is introduced in this paper. In this theory, the relationship among the physical properties and crystal structure, preparation method and doping content is set up. The parabola equation that can be fixed to test curve and that has the reliable physical meaning is given. The extreme value of this equation confirms the quantitative relationship between the optimal doping content, the crystal structure and the preparation method. This an expression of the optimal doping content is obtained. The experimental results of doping modified for blood compatibility of titanium oxide films are analyzed. Using this expression to calculate the Ta5+ optimal doping content in blood compatibility of titanium oxide films.

Biocompatible Materials↗