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Q Li

Publications and source records attributed to Q Li.

At least 757 records · Page 42Linked to original sources
PubMed1996

Compound 48/80-induced conjunctivitis in the mouse: kinetics, susceptibility, and mechanism.

A mouse model of conjunctivitis has been developed by topical application of compound 48/80 (C48/80), an agent that triggers mast cell degranulation. We examined the responsiveness of C57BL/6, C3H/HeN, and ASW/J mouse strains to C48/80 stimulation, and of a mutant strain with mast cell depletion (WBB6F1/J and its sham control). Conjunctivae were collected and examined histopathologically at 15 min and 1,6,24,48 and 72 h after topical C48/80 administration. Conjunctival inflammation developed in all strains, although the severity varied. The conjunctivitis was characterized clinically by irritation, discharge, erythema, and chemosis. Pathology showed conjunctival infiltration with neutrophils, macrophages, CD4+ T lymphocytes, and a few eosinophils. Degranulation of mast cells and evacuation of goblet cells were also observed. Late-phase inflammatory reactions peaked 6-24 h after C48/80 administration and resolved by 48-72 h. WBB6F1/J mice had much less inflammation than their sham controls. In conclusion, topical C48/80 induced a conjunctival inflammatory response similar to allergen-induced conjunctivitis. The depletion of mast cells significantly reduced the inflammation. This model which consistently mimics the clinical signs and histopathological processes of allergic conjunctivitis in humans, is practical and reliable for the evaluation of new anti-allergic medications and for the investigation of conjunctival cellular responses in the allergic inflammatory cascade.

Animals↗
PubMed1996

Determinants of maternal mortality in rural China.

A case-control study of maternal mortality was conducted in selected rural areas of two provinces in China: Henan province, which has a relatively lower socio-economic status and higher maternal mortality rates, and Jiangsu province with higher socio-economic status and lower maternal mortality rates. The major cause of maternal mortality in the two provinces was postpartum hemorrhage and the largest proportion of deaths occurred on the road between the women's home and the health care facility. Results indicate that the expectant mother's socio-economic status, knowledge of maternal care, and the nature and level of maternal care provided all influence rural maternal death rates. However, socio-economic factors were only significant predictors of mortality in the poorer province. Implications for health policy and future research are discussed.

Age Factors↗
PubMed1996

Gamma interferon induced increases in intracellular cathepsin B activity in PMA primed THP-1 cells are blocked by inhibitors of protein kinase C.

Macrophage proteinases including cathepsin B (CB) are implicated in the tissue injury of inflammatory lesions. We have previously shown that interferon-gamma (IFN-gamma) increases intracellular levels of the lysosomal proteinase, CB, in THP-1 cell primed with phorbol 12-myristate 13-acetate (PMA). We have now examined the role of protein kinase C (PKC) in this effect. Following activation with PMA, the intracellular CB activity was significantly increased in the presence of 500 U/ml IFN-gamma. With the addition of protein kinase C (PKC) inhibitors bisindolylmaleimide, staurosporine, H-7, or phloretin a reversal of the effect of IFN-gamma was noted whereas the addition of the cyclic nucleotide-dependent protein kinase inhibitors HA 1004, H-8, H-89, or cAMP-Dependent Protein Kinase (PKA) Inhibitor did not block the effect. Although diacylglycerol (DAG) did not replace PMA in the study. Diacylglycerol Kinase Inhibitor induced a more pronounced augmentation and PKC depletion inhibited the effect. This suggests that a PKC-dependent pathway is involved in the response of CB in PMA primed THP-1 cells to IFN-gamma.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1996

A novel synthetic inhibitor of endopeptidase-24.15.

A novel synthetic inhibitor of endopeptidase-24.15 (EP-24.15, EC 3.4.24.15), N-[(2R,4R)-2-(2-hydroxyphenyl)-3-(3-mercaptopropionyl)-4-thiazolidine carbonyl] -L-phenylalanine (SA898) is described. This compound inhibited rat EP-24.15 competitively with an IC50 of 23 nM and Ki of 9.1 nM. These values were, respectively, 9.6 times and 6.3 times smaller than those for N-(1-carboxy-3-phenylpropyl)-alanyl-alanyl-phenylalanyl-p-aminobenzoate (cFP-AAF-pAB), which was one of the most potent inhibitors thus far reported. The inhibitory effect of SA898 on other endopeptidases, angiotensin converting enzyme (ACE, EC 3.4.15.1) and endopeptidase-24.11 (EP-24.11, EC 3.4.24.11) was also studied. SA898 inhibited ACE significantly, but the potency was about 20-fold lower than that for EP-24.15 in terms of the Ki value. The inhibitory effect of SA898 on EP-24.11 was almost negligible (Ki = 28 microM). In addition, the inhibitory activities of several SA898-related compounds were examined. Based on these data, the structure-activity relationships for EP-24.15 inhibitors are discussed.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Erythropoietin-like activity in vivo of the fusion protein rhIL-6/IL-2 (CH925).

CH925 is a novel cytokine of a fusion protein interleukin-6 (IL-6)/IL-2 exhibiting erythropoietin (Epo)-like effects in vivo and ex vivo, in addition to its enhanced effects compared to IL-2 and IL-6 reported by us previously, which indicates its potential clinical use. Our present study was undertaken to determine the Epo-like activity of CH925 in vivo. The reticulocyte response was observed in transfusion-induced polycythemic mice by using flow cytometry with pyronin Y staining. On day 2 after injection of CH925, the average number of reticulocytes was 2.11% in the group given 250 micrograms/kg/d and 1.01% for 100 micrograms/kg/d. The mean fluorescence intensity (MFI) also significantly increased. Longitudinal studies of CH925 were performed on days 2, 4, and 10, and reticulocyte counts increased up to a peak on day 4. Activity of CH925 (100 micrograms/kg/d) corresponds to 1 U of standard rhEpo in our study.

Animals↗
PubMed1996

Hepatocyte growth factor and hepatocyte growth factor receptor in the lacrimal gland, tears, and cornea.

PURPOSE: The purpose of this study was to characterize the expression of hepatocyte growth factor (HGF) and HGF receptor proteins in lacrimal gland, tears, and cornea. METHODS: The reverse transcription-polymerase chain reaction method was used to detect HGF and HGF receptor messenger RNA in human lacrimal gland tissue. HGF and HGF (c-met) receptor monoclonal antibody specificity was demonstrated with fluorescent antibody sorting of cells engineered to express HGF or HGF receptor compared with control cell lines, enzyme-linked immunoadsorbent assay (ELISA), immunoprecipitation, and immunohistology with preabsorption. Immunohistochemistry was applied to study the distribution of HGF and HGF receptor expression in rabbit lacrimal gland tissue and in wounded and unwounded rabbit cornea. An ELISA was used to detect HGF in pooled samples of human tears and individual aliquots of tears collected from patients 1 day after anterior segment surgery. RESULTS: Amplification products of the expected size for HGF and HGF receptor mRNAs were detected in lacrimal tissue and were confirmed to be specific by hot blotting and nucleic acid sequencing. Hepatocyte growth factor protein was detected in interalveolar and interlobular connective tissue cells adjacent to glandular alveolar (acinar) cells and associated with the cells lining the interlobular ducts. Hepatocyte growth factor receptor protein was expressed in the glandular alveolar and interlobular ductal cells in the lacrimal gland and all three cell types of the cornea. It was detected in keratocyte and endothelial cells, and expression was increased in keratocytes after epithelial wounding. Hepatocyte growth factor was not present in corneal epithelial cells, but in the unwounded cornea a strong signal was associated with the epithelial cell surface. It was detected by ELISA in pooled normal tears at levels 186 to 290 pg/ml and in individual postoperative tear samples at 453 to 619 pg/ml. In some tear samples, HGF levels were below the sensitivity of the assay (97.5 pg/ml). CONCLUSIONS: The distribution of HGF receptor protein expression in the lacrimal gland suggests that HGF secreted by interalveolar connective tissue cells traverses the acinar cells and modulates functions in acinar and ductal epithelial cells. Hepatocyte growth factor likely collects within the interlobular ducts and becomes a component in normal tears. Thus, lacrimal gland HGF probably modulates corneal epithelial cell proliferation, motility, and differentiation. Its expression in keratocytes is upregulated after corneal epithelial wounding and probably contributes to the epithelial wound healing process.

Animals↗
PubMed1996

Adeno-associated virus 2-mediated transduction and erythroid cell-specific expression of a human beta-globin gene.

Recombinant adeno-associated virus 2 (AAV) virions were constructed that contained the genomic copy of a normal human beta-globin gene marked with a 4-bp Clal linker, and the herpesvirus thymidine kinase (TK) promoter-driven bacterial gene for resistance to neomycin (v beta m-globin), as well as those containing the DNase l-hypersensitive site 2 (HS-2) from the locus control region (LCR) of the human beta-globin gene cluster (vHS2-beta m-globin). These recombinant virions were used to infect a human erythroleukemia cell line which normally does not express the beta-globin gene (K562), or a human nasopharyngeal carcinoma cell line (KB). Cell populations resistant to G418, a neomycin analogue, were obtained following infections with the recombinant virions, indicating high-efficiency transduction of the chimeric gene as well as functional activity of the transduced neo gene in both cell types. Southern blot analysis using a human beta-globin DNA probe substantiated stable integration of the exogenous beta-globin allele in these cells. There was no expression of the transduced beta-globin gene in K562 or KB cells infected with the v beta m-globin virus. High-level expression of the transduced beta-globin gene occurred only in the vHS2-beta m-globin virus-infected K562 cells, but not in KB cells, as determined by Northern blot as well as RNase protection analyses. Expression of the human beta-globin protein could also be detected in approximately 10-20% of the vHS2-beta m-globin virus-infected K562 cells. These studies suggest that the AAV-based vector system may prove useful for high-efficiency globin gene transfer in human hematopoietic cells.

Dependovirus↗
PubMed1996

Catecholamine secretion induced by nicotine is due to Ca++ channel but not Na+ channel activation in porcine adrenal chromaffin cells.

Secretion induced by nicotinic agonists in adrenal chromaffin cells depends on membrane depolarization produced by the opening of nicotinic receptor channels. It is generally believed that membrane depolarization activates voltage-gated Na+ channels, leading to the generation of action potentials and the subsequent activation of voltage-gated Ca++ channels. However, our results indicate that, in cultured porcine chromaffin cells, Na+ channels and action potentials play little role in nicotine-induced secretion. Although removal of extracellular Na+ blocked secretion produced by nicotine, tetrodotoxin, which abolished voltage-activated Na+ currents, had no effect on nicotine-induced secretion, even at low nicotine concentrations. The blocking effect of Na+ removal on nicotine-induced secretion could be reversed by adding excess extracellular Ca++ (20 mM), a reversal which was inhibited by the dihydropyridine Ca++ channel blocker, nimodipine (2 microM). Nimodipine also blocked nicotine-induced secretion under normal ionic conditions, but had little effect on nicotine-induced depolarization. When measured using a perforated patch (nystatin), current clamp technique, nicotine produced a rapid and sustained depolarization which included an initial volley of 1 to 15 action potentials. In contrast, when measured using a standard whole-cell, current clamp configuration, nicotine produced a slower depolarization and numerous action potentials. These results suggest that voltage-gated Ca++ channels in porcine chromaffin cells are activated directly by persistent depolarization produced by Na+ entry through the nicotinic receptor channel under normal ionic conditions, and by Ca++ entry through the nicotinic receptor channel in the absence of Na+, but the presence of high extracellular Ca++.

Animals↗
PubMed1996

The Fas-Fas ligand system and other modulators of apoptosis in the cornea.

PURPOSE: Previous studies have suggested that the disappearance of anterior keratocytes after injury to the overlying epithelium is mediated by apoptosis. The authors examined the expression of the apoptosis-related modulators, Fas (receptor), Fas ligand, Bax, Bcl-2, Bcl-XL, and interleukin-1 beta converting enzyme (ICE) in corneal cells as candidate mediators of this response and tested the effect of Fas receptor-stimulating antibody on corneal stromal fibroblast cells in vitro. METHODS: Reverse-transcription-polymerase chain reaction was used to detect FAS, FAS ligand, Bax, Bcl-2, Bcl-XL, and ICE mRNA expression in primary cultures of human corneal epithelial, stromal fibroblast, and endothelial cells. Immunohistochemistry was applied to detect Fas and Fas ligand proteins in fresh-frozen sections of normal human cornea. The effect of FAS-stimulating monoclonal antibody on first-passage stromal fibroblasts was studied using a DNA fragmentation assay, the live-dead assay with fluorescent microscopy, toluidene blue staining with light microscopy, and electron microscopy. RESULTS: FAS, Fas ligand, Bax, Bcl-2, Bcl-XL, and ICE mRNAs are expressed in all three major cell types of the cornea. Fas protein is expressed in corneal epithelial, keratocyte, and endothelial cells in fresh-frozen human cornea. Fas ligand protein, however, was detected in corneal epithelial and endothelial, but not keratocyte, cells. Fas-stimulating antibody induced first-passage stromal fibroblast cell death with morphologic changes and DNA fragmentation consistent with apoptosis. CONCLUSIONS: The Fas system (Fas and Fas ligand) modulators and final common pathway mediators of apoptosis are expressed in corneal cells. The distribution of Fas (epithelial, keratocyte, and endothelial cells) and Fas ligand (epithelial and endothelial cells) protein expression in fresh-frozen corneal tissue suggests that Fas ligand expressed in corneal epithelial and endothelial cells modulates functions in keratocyte cells and, possibly, autocrine-juxtacrine functions in epithelium and endothelium. The Fas-Fas ligand system is expressed in the cornea and could have important functions in normal corneal physiology and in the pathophysiology of corneal disease, including modulation of keratocyte apoptosis after epithelial injury.

Amino Acid Sequence↗
PubMed1996

Uridine nucleotide selectivity of three phospholipase C-activating P2 receptors: identification of a UDP-selective, a UTP-selective, and an ATP- and UTP-specific receptor.

Observation that the G protein-coupled P2U receptor (P2Y2 receptor) is activated by UTP as well as ATP provided the first indication that a class of uridine nucleotide-responsive receptors might exist. This hypothesis was confirmed by our identification of a uridine nucleotide-specific receptor on C6-2B rat glioma cells and by the recent cloning of two uridine nucleotide-responsive receptors, the P2Y6 receptor [J. Biol. Chem. 270:26152-26158 (1995)] and the P2Y4 receptor [J. Biol. Chem. 270:30849-30852 (1995) and J. Biol. Chem. 270:30845-30848 (1995)]. The relative nucleotide selectivities of these uridine nucleotide-activated receptors have not been established. Therefore, we cloned and expressed the P2Y6 and P2Y4 receptors in 1321N1 human astrocytoma cells and compared their relative selectivities for UDP, UTP, and other uridine and adenine nucleotides with that of the P2Y2 receptor expressed in the same cells. These comparisons were made by measuring inositol phosphate accumulation under conditions in which the initial purity and stability of agonists were rigidly ensured and quantitatively assessed. The data indicate that the P2Y2 receptor is activated with similar potencies by ATP and UTP but not by ADP or UDP; the P2Y6 receptor is activated most potently by UDP but weakly by UTP, ATP, and ADP; and the P2Y4 receptor is activated most potently by UTP, less potently by ATP, and not at all by nucleotide diphosphates. Furthermore, the P2Y6 receptor, which displays a uridine nucleotide selectivity essentially identical to that of the uridine nucleotide-specific receptor in C6-2B cells, was shown to be natively expressed in C6-2B cells and to account for the uridine nucleotide responses originally identified in these cells. These results define the uridine nucleotide selectivity of three phospholipase C-linked receptors: a receptor that is selectively activated by UDP (P2Y6 receptor), selectively activated by UTP (P2Y4 receptor), and activated by UTP and ATP but not by diphosphate nucleotides (P2Y2 receptor).

Adenosine Triphosphate↗
PubMed1996

Aggregation of phospholipid vesicles induced by the ribosome inactivating protein saporin.

Saporin-S6(SO-6) is a single chain ribosome inactivating protein, which can inhibit protein synthesis by inactivating eukaryotic ribosomes. The interaction of SO-6 with phospholipid model systems was described. SO-6 can specifically interact with negatively-charged phospholipid vesicles and it induces the aggregation of the lipid vesicles. The kinetics of the vesicle aggregation induced by SO-6 was studied. The saturating protein/lipid molar ratio was determined to be 1:100 based on titration experiments. The aggregation is dependent on the temperature in a range that was many times higher than the phase transition temperature of the phospholipid. The effect of pH on the aggregation of the vesicles can not be explained by simple deprotonation of side chain amino groups of the protein, and may be related to conformational changes of the protein. The maintenance of physiological ionic strength was required for the aggregation of SO-6 with vesicles. Finally, the interaction was prompted by Ca2+ ions, and was totally inhibited by EDTA, which suggests that SO-6 may interact with phospholipid vesicles in a Ca(2+)-dependent manner.

Calcium↗
PubMed1996

Expression and secretion of rabbit plasma cholesteryl ester transfer protein by Pichia pastoris.

The rabbit cholesteryl ester transfer protein (CETP) was expressed in the methylotrophic yeast Pichia pastoris by introducing the CETP cDNA under the control of the methanol-inducible alcohol oxidase promoter. The cDNA was cloned from in vitro amplified cDNA of rabbit liver mRNA. The nucleotide sequence of the cloned cDNA differed slightly from the previously published sequence that changed the amino acid sequence in six residues. Interestingly, five of these replacements are identical to the corresponding residues in human CEPT. In addition, the encoded mature N-terminal sequence was changed from Cys- to Arg-Glu-Phe- to link the CETP sequence to the yeast acid phosphatase signal peptide. The culture medium of the transformed cells induced with 1% methanol contained both cholesteryl ester and triglyceride transfer activity comparable to that of rabbit plasma. Like rabbit plasma, the lipid transfer activity in the medium could be inhibited by monoclonal antibodies that block CE/TG transfer or TG transfer alone. Immunoblot analysis of M(r) = 80 K and minor species of M(r) = 60-100 K. In spite of these differences, the specific transfer activity of the recombinant CETP was indistinguishable from that of rabbit plasma CETP of M(r) = 74 K. N-Glycosidase F treatment converted both the recombinant and plasma CETP to a single species of M(r) = 55 K. Both the plasma and recombinant CETP lost their activity after removal of N-linked carbohydrate and sialic acid. A single 55 K component was found in the cell-lysates. The intracellular form of the recombinant CETP was not modified by N-glycosidase F treatment. In conclusion, the recombinant CETP is synthesized as an inactive polypeptide that is processed and secreted as a functional glycoprotein. In addition, the N-terminal Cys residue of the plasma CETP is not required for its activity.

Amidohydrolases↗
PubMed1996

[Detection of bacterial vaginosis in gram stained vaginal smears and papanicolaou stained cervical smears].

OBJECTIVE: To determine the sensitivity and specificity of diagnosis of bacterial vaginosis (BV) by papanicolaou (PAP)-stained cervical smears and gram-stained vaginal smears according to clinical criteria. METHODS: In the prospective study of 196 non-pregnant women of child-bearing age, 94 were clinically diagnosed to have BV. Gram-stained vaginal smears and PAP-stained cervical smears were collected from all enrolled patients. RESULTS: In comparison with clinical diagnosis of BV, the sensitivity and specificity of gram-stained vaginal smears and PAP-stained cervical smears were 94.7% (89/94), 98.0% (100/102) 85.1% (80/94), and 95.1% (97/102). The characteristics of BV in gram-stained vaginal smears and PAP-stained cervical smears included small bacteria of Gardnerella and bacteroides morphotypes and curved gram variable rods and absence of bacteria of Lactobacillus morphotypes. CONCLUSION: It is possible to screen and manage BV according to Gram-stained vaginal smears or PAP-stained cervical smears.

Adult↗
PubMed1996

[Study on the geographic distribution and serological typing of HFRS in Hebei Province].

Surveillance on the HFRS had been carried out during the period of 1986-1993. Rodent density ranged from 4.6%-12.2% with R.norvegicus exceeding 60% in all kinds of rodents. HV antigen carrier rate of R.norvegicus was 1.3%-7.5%, much higher than that among other rodents. A significantly positive correlation had been observed between the HFRS morbidity and the R.norvegicus density. Of 129 specimens from HFRS patients, 89% belonged to the type of SEOV. In the eastern and centre Parts of Hebei plain, HTNV occupied 1.6%. A total number of 9,609 HFRS patients had been identified during the period of 1980-1993. The plain area in Hebei province was recognized as the major epidemic area. The key measure for decreasing the HFRS morbidity was deratizationin in the residential area in January and February and immunization with HFRS inactivated vaccine.

Animals↗
PubMed1996

[Ultrastructural and immunohistochemical localization of endothelin-1 in nonneoplastic, hyperplastic and neoplastic adrenal gland].

OBJECTIVE: To determine the ET-1 immunoreactivity in human nonneoplastic, hyperplastic and neoplastic adrenal gland ultrastructurally and histologically. METHODS: Sensitive immunohistochemical technique was used. RESULTS: The ET-1 immunoreactivity was found in non-neoplastic (100%), adrenal cortical adenoma (100%) and cortical carcinoma (3/10). ET-1 immunoreactivity was regularly seen in the cortex, especially in zona fasciculata and to a varying extent also in the other two zones, but not in the medulla. The immunoreactive material in the cytoplasm was mostly in vacuolar or grain-like structures. Focally, cell membrane also showed immunoreactive staining. Most cortical adenomas displayed numerous immunoreactive cells. The immunoreactivity in the tumor tissue was in the same forms as in normal cortex, but the reactive products were generally few. No obvious differences in immunostaining were seen between the aldosterone- and cortisol-producing adenomas or the non-functioning ones. Three of the ten carcinomas contained immunoreactive cells, but they were few and appeared focally. The ET-1 immunoreactive structures were seen as "dust-like" material. Electronmicroscopical investigation revealed ET-1 immunoreactive products adjacent to the outer surface of the membrane of lipid bodies, in mitochondria, rough endoplasmic reticulum and focally on the cell membrane, but no immunolabelling was seen in the medulla. CONCLUSIONS: The localization of ET-1 in the endoplasmic reticulum indicates that this peptide is synthesized in the cortical cells. The localization in the membrane of the lipid bodies and in the mitochondria indicates that it may take part in steroid synthesis. The focally immunolabelled cell membranes may depend on ET-1 bond to ET receptors. The difference in immunoreactivity between the benign and the malignant cortical neoplasms may be of diagnostic value.

Adrenal Cortex Neoplasms↗
PubMed1996

[Inhibition of genomic HDV ribozyme activity by antisense oligodeoxynucleotides].

OBJECTIVE: To study inhibitory effect of antisense oligodeoxynucleotides (asODNs) on genomic HDV ribozyme activity. METHODS: Plasmid pHDVrz277 used to transcribe a 112 nucleotides (nt) genomic HDV ribozyme constructed earlier in our laboratory. It had genomic and antigenomic HDV ribozyme sequences from 665-941nt. The inhibitory effect of five asODNs on genomic HDV ribozyme activity was studied to select the potential effective sequences in vitro. RESULTS: The results showed that asODN, being complementary to 683-703nt (stem I and self-cleavage site), completely blocked the activity of a 112nt genomic HDV ribozyme transcription in vitro. The inhibition rate of asODNs against 756-770nt (SSrB) and 721-735nt (SSrA) were 69.36% and 48.64% respectively. However, two asODNs covered the 736-750nt (stem IV) and 704-720nt (SSrC) showed almost no inhibitory effect on genomic HDV ribozyme. Fine sequence specificity testing at region 683-703nt revealed that asODN as small as 13 nt flanking the self-cleavage site (683-695nt) retained a high inhibition rate (> 90%). CONCLUSION: The results suggested that stem I and SSrB may play an important role in genomic HDV ribozyme and asODNs can block genomic HDV ribozyme activity almost completely.

Genome, Viral↗