Neuroprotective mechanism of bromocriptine.
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ATP-Binding Cassette Transporters↗
Biomedical subjects
Y X Zhang
Publications and source records attributed to Y X Zhang.
Inhibition by folded isomers of L-2-(carboxycyclopropyl)glycine of glutamate uptake via the human glutamate transporter hGluT-1.
The effects of isomers of 2-(carboxycyclopropyl)glycine (CCG) on uptake of L-glutamate were investigated in COS-7 cells that expressed a cloned human glutamate transporter (hGluT-1). The (2S, 3S, 4R)-isomer (L-CCG-III) and the (2S, 3R, 4S)-isomer (L-CCG-IV) markedly inhibited glutamate uptake with a 50% inhibitory concentration of 290 nM and 1.1 microM, respectively. The (2S, 3S, 4S)-isomer (L-CCG-I) and the (2S, 3R, 4R)-isomer (L-CCG-II) did not inhibit glutamate uptake at concentrations of < or = 10 microM. Thus, hGluT-1 showed a markedly higher affinity for L-CCG-III and L-CCG-IV with a folded conformation of the glutamate skeleton, than for L-CCG-I or L-CCG-II with an extended conformation.
ATP-Binding Cassette Transporters↗
Effect of nicotine on dopamine uptake in COS cells possessing the rat dopamine transporter and in PC12 cells.
The effect of nicotine on the uptake of dopamine (DA) is not completely understood. We studied its effect on PC12 cells and on COS cells transfected with the rat DA transporter cDNA (pcDNADAT1). DA uptake by PC12 cells was inhibited by nicotine in a concentration-related fashion. Treatment of PC12 cells with nerve growth factor (NGF) increased such inhibition. This inhibitory effect was abolished by hexamethonium and mecamylamine, indicating that nicotine acted via the nicotinic acetylcholine (nACh) receptors in PC12 cells. This view is also supported by evidence that acetylcholine (ACh) reduced the uptake of DA in a hexamethonium-, but not atropine-, sensitive fashion. However, nicotine failed to inhibit DA uptake by COS cells possessing the DA transporter. These results suggest that the inhibitory effect of nicotine on DA uptake, when coupled with an nACh receptor leading to an indirect action on the transporter, may play a role in regulating extracellular concentrations of DA.
Acetylcholine↗
Identification of a protein with homology to hsp90 that binds the type 1 tumor necrosis factor receptor.
The yeast-based two hybrid has been used to identify a novel protein that binds to the intracellular domain of the type 1 receptor for tumor necrosis factor (TNFR-1IC). The TNF receptor-associated protein, TRAP-1, shows strong homology to members of the 90-kDa family of heat shock proteins. After in vitro transcription/translation and 35S labeling, TRAP-1 was precipitated using a fusion protein consisting of glutathione S-transferase and TNFR-1IC, showing that the two proteins directly interact. The ability of deletion mutants of TNFR-1 to interact with TRAP-1 was tested using the two hybrid system. This showed that the amino acid sequences that mediate binding are diffusely distributed outside of the domain in the C terminus of TNFR-1IC that signals cytotoxicity. The 2.4-kilobase TRAP-1 mRNA was variably expressed in skeletal muscle, liver, heart, brain, kidney, pancreas, lung, and placenta. TRAP-1 mRNA was also detected in each of eight different transformed cell lines. Identification of TRAP-1 may be an important step toward defining how TNFR-1, which does not contain protein tyrosine kinase activity, transmits its message to signal transduction pathways.
Amino Acid Sequence↗
Mechanisms of 4-quinolone resistance in quinolone-resistant and methicillin-resistant Staphylococcus aureus isolates from Japan and China.
Ninety-two and 33 methicillin-resistant Staphylococcus aureus (MRSA) strains were isolated in Japan and China respectively. They were categorised as ofloxacin-susceptible (MIC < 12.5 mg/L), moderately (MIC 12.5-25 mg/L) or highly (MIC > or = 50 mg/L) ofloxacin-resistant. 4-Quinolone concentrations required to inhibit purified DNA gyrase from the moderately and highly quinolone-resistant MRSA were at least 20 times higher than those required to inhibit the equivalent enzyme from quinolone-susceptible strains. Reconstitution assays demonstrated that the 4-quinolone-resistant MRSA had a mutation in subunit A of DNA gyrase. A portion of the gyrA gene from amino acids codons 40-115 was sequenced. Four moderately resistant and seven highly resistant MRSA contained a Ser-->Leu substitution at amino acid 84; one moderately and one highly resistant MRSA and one moderately resistant methicillin-susceptible S. aureus (MSSA) strain contained a Glu-->Lys substitution at amino acid 88. Eight MRSA, including one quinolone-susceptible strain and one MSSA contained a silent mutation at amino acid 86. Uptake of ofloxacin in moderately resistant strains was almost the same in the presence or absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), whereas in highly resistant strains, uptake increased when CCCP was added. Restriction fragment length analysis of the norA gene with the restriction endonuclease SfcI showed a mutation of nucleotide position 1085 in all MRSA strains tested except for one highly quinolone-resistant strain. Thus the mechanisms of 4-quinolone-resistance in these MRSA isolates involved alterations in both DNA gyrase and antimicrobial uptake and efflux.
Anti-Infective Agents↗
Protective efficacy of major outer membrane protein-specific immunoglobulin A (IgA) and IgG monoclonal antibodies in a murine model of Chlamydia trachomatis genital tract infection.
The protective efficacy of immunoglobulin A (IgA) and IgG monoclonal antibodies (MAbs) specific for the major outer membrane protein of Chlamydia trachomatis MoPn was evaluated in a murine genital tract infection model. MAbs were delivered into serum and vaginal secretions of naive mice by using the backpack hybridoma tumor system, and protective efficacy was assessed over the first 8 days following challenge by quantitative determination of chlamydial recovery from cervicovaginal swabs, histopathological evaluation of genital tract tissue, and immunohistochemical detection of chlamydial inclusions. IgA and IgG significantly reduced the incidence of infection following vaginal challenge with 5 50% infectious doses, but such protection was overwhelmed by 10- and 100-fold higher challenge doses. Both MAbs also consistently reduced vaginal shedding from infected animals with all three challenge doses compared with the negative control MAb, although the magnitude of this effect was marginal. Blinded pathological evaluation of genital tract tissues at 8 days postinfection showed a significant reduction in the severity of the inflammatory infiltrate in oviduct tissue of infected IgA- and IgG-treated animals. Immunohistochemical detection of chlamydial inclusions revealed a marked reduction in the chlamydial burden of the oviduct epithelium; this finding is consistent with the reduced pathological changes observed in this tissue. These studies indicate that the presence of IgA or IgG MAbs specific to major outer membrane proteins has a marginal effect in preventing chlamydial colonization and shedding from the genital tract but has a more pronounced effect on ascending chlamydial infection and accompanying upper genital tract pathology.
Animals↗
[Cost-benefit analysis on immunization of newborns with hepatitis B vaccine in Jinan City].
The decision tree model cost-benefit analysis method was used to analyse the strategies and economic benefits of immunization of newborns with hepatitis B vaccines in Jinan City. The results showed that all the three vaccination strategies could all produce positive benefits. Their BCR were 42.41 to 48.01. Through the decision analysis, it concluded that stress should be laid on the blocking of mother-to-infant transmission, and that if there are sufficient HB vaccines, all newborns should be vaccinated. In addition, the results of sensitivity analysis indicate that the benefits of HB vaccination are outstanding and quite stable.
China↗
The sequence of the groES and groEL genes from the mouse pneumonitis agent of Chlamydia trachomatis.
The co-transcribed structural genes, groES and groEL, of the groE stress response operon from Chlamydia trachomatis mouse pneumonitis (MoPn), were cloned and sequenced. The calculated molecular masses of the encoded heat-shock proteins (Hsp), a small Hsp (GroES) and Hsp60 (GroEL), are 11,089 and 58,367 Da, respectively. By comparison with other known chlamydial groES and groEL sequences, there is 89 and 94% nucleotide (nt) identity with C. trachomatis human strains (serovars A and L2), 77 and 82% with C. psittaci strain GPIC, and 75 and 80% with C. pneumoniae isolate AR-39. At the amino-acid level, the MoPn Hsp60 shows a 99% identity with those from C. trachomatis human strains. In a mouse model, MoPn Hsp60 could prove useful in deciphering the pathogenesis of human chlamydial diseases.
Amino Acid Sequence↗
Effects of captopril and nadolol on renal hemodynamics in patients with essential hypertension.
The randomized single-blind study was designed to compare the effects of captopril (Cap) and nadolol (Nad) on renal hemodynamics in 60 patients with essential hypertension. They were divided into two groups at random. Cap was given in dosage of 37.5-75 mg/d per os and Nad 40-80 mg/d. The results show that both drugs increase the blood volume distributed to the kidneys from cardiac output (renal blood flow/cardiac output), Cap increasing 10% (P < 0.05) and Nad 8% (P < 0.05). Renal vascular resistance (RVR) is lowered by the two drugs, 13% (P < 0.05) by Cap and 11% (P < 0.05) by Nad. These suggest that both drugs facilitate the maintenance of renal blood circulation in patients with essential hypertension, being beneficial for long-term treatment of hypertension.
Adult↗
Protective immunity induced by 67 K outer membrane protein of phase I Coxiella burnetii in mice and guinea pigs.
A 67 K outer membrane protein (OMP) isolated from phase I Coxiella burnetii QiYi strain was purified with monoclonal antibodies (MoAb) coupled to CNBr-Sepharose 4B. Chemical analyses of the 67 K protein showed that it contained seventeen kinds of amino acids and no LPS. The immunogenicity and protectivity of the 67 K protein against C. burnetii was evaluated in mice and guinea pigs by in vitro lymphocyte proliferation assay, delayed-type skin test, antibody conversion rate, and immunization and challenge tests. Intraperitoneal injection of the 67 K protein resulted in antibody production against phase I and II whole cell antigens. The anti-67 K antibody conversion rate was found to be 100% in mice and guinea pigs as well. Lymphocytes were responses in vitro to specific antigen. In addition, delayed-type hypersensitivity appeared two weeks after immunization with the 67 K protein. Moreover, 100% of mice and guinea pigs inoculated with the 67 K protein were protected against a challenge with 10(3) ID50 virulent C. burnetii. In conclusion, these results demonstrate that the 67 K OMP elicits in vivo and in vitro both B cell-mediated and T cell-mediated immunity in mice and guinea pigs. Thus the 67 K protein is a candidate for an effective subunit vaccine against Q fever.
Animals↗
[Clinical investigation of erythrocyte function in patients with lung cancer].
With a yeast-erythrocyte-SPA rosette method, the function of erythrocyte immune adherence was determined in 49 cases of lung cancer, 20 cases of benign pulmonary diseases and 60 healthy persons. By means of simple morphologic method and pyrogallol autoxication method, the function of erythrocyte enhancing neutrophils phagocytosis and the activity of RBC-CuZnSOD were measured in some of these subjects. It was found that both the function of red cell immune adherence and the effect of erythrocyte enhancing phagocytosis in the patients with lung cancer were significantly weaker than in the cases of benign pulmonary diseases and the healthy subjects. The function of erythrocyte immune adherence tended to recover after effective surgical treatment. In comparison with the healthy persons, the activity of RBC-CuZnSOD was significantly lower in the patients with lung cancer. The mechanism and clinical significance of the changes in erythrocyte function were discussed.
Adult↗
Monoclonal antibodies define genus-specific, species-specific, and cross-reactive epitopes of the chlamydial 60-kilodalton heat shock protein (hsp60): specific immunodetection and purification of chlamydial hsp60.
Ocular and urogenital tract infections with Chlamydia trachomatis can progress to chronic inflammatory diseases that produce blindness and tubal infertility. The pathophysiology of these chronic disease conditions is thought to be immunologically mediated, and the chlamydial 60-kDa heat shock protein (hsp60) has been implicated as a major target antigen that stimulates the immunopathological response. The lack of chlamydial hsp60 antibodies and purified hsp60 has severely restricted studies to define more thoroughly the role of this protein in the immunopathogenesis of chlamydial disease. We produced a panel of antichlamydial hsp60 monoclonal antibodies (MAbs) and defined their specificities by immunoblotting against lysates of C. trachomatis, C. psittaci, and six other genera of bacteria. Three patterns of anti-hsp60 immunoreactivity were observed: chlamydial species specific, chlamydial genus specific, and cross-reactive. The epitopes recognized by these MAbs were localized within the primary amino acid sequence of hsp60 by immunoblotting against recombinant amino-terminal truncated hsp60 fusion polypeptides and then precisely mapped by use of overlapping synthetic peptides. The majority of the MAbs mapped to either the amino or the carboxyl termini of hsp60. Epitopes defining all three MAb reactivities mapped within amino-terminal residues 6 to 16. Genus-specific hsp60 MAbs mapped to epitopes located within this region and to residues 17 to 28 and 177 to 189. Antichlamydial hsp60 MAbs stained inclusions as effectively as MAbs specific for the major outer membrane protein. Homogeneous preparations of full-length recombinant chlamydial hsp60 and amino-terminal truncated recombinant hsp60 polypeptides were obtained by immunoabsorption chromatography with an hsp60 MAb reactive to the carboxyl terminus of the protein. Thus, the antichlamydial MAbs described here should be extremely useful for the specific immunodetection of hsp60 in tissues from individuals having different disease manifestations and for the purification of hsp60 or truncated hsp60 polypeptides for use in serologic and lymphocyte proliferation assays. The availability of these MAbs will facilitate studies to define more precisely the role of hsp60 in the immunopathogenesis of chlamydial disease.
Amino Acid Sequence↗
[Diagnostic significance of multinuclear giant cells in lymph node fine needle aspiration].
Enlarged lymph nodes, commonly seen in inflammatory or tumorous conditions, is often suspected as Hodgkin's disease in cytologic diagnosis. Twenty cases originally diagnosed as Hodgkin's disease by fine needle aspiration of lymph nodes are reported. Eighteen of these 20 cases were checked by histopathology. It was found that only 3 had reached the correct diagnosis. The authors believe that by thorough understanding of the origin and characteristics of various types of multinuclear giant cells, differentiation from Hodgkin's disease is possible.
Biopsy, Needle↗
[Hepatitis B virus DNA in the serum of anti-HBs positive persons].
In order to investigate the significance of HBV DNA in the serum of anti-HBs positive persons, the serum of 76 anti-HBs positive persons was studied for HBV DNA by means of polymerase chain reaction (PCR). The results showed that 21 (32.2%) out of 65 cases without hepatitis B vaccination were positive for HBV DNA detected with PCR (PCR-HBV DNA), but no one was positive for PCR-HBV DNA in 11 cases inoculated against hepatitis B. It was also found that 6 cases were positive for HBsAg-Ab immunocomplex in those positive for PCR-HBV DNA and the liver tissue in 2 of the 5 cases with liver-biopsy were positive for HBVAg determined with immunohistologic ABC method. We believed that persons, who acquired anti-HBs after HBV infection were different from those who were vaccinated, might carry HBV which come from the HBsAg-Ab immunocomplex and HBVAg positive hepatocytes. In addition, the study also proved that the PCR-HBV DNA positive rate correlated significantly with the anti-HBe and or anti-HBc positive rate and with the abnormal rate of liver function in the anti-HBs positive persons. It was suggested that persistent presence of HBV DNA in the bodies should be responsible for the persistent presence of anti-HBe and anti-HBc in the serum and also for the liver damage.
Acute Disease↗
Trace elements in full-term neonate hair.
Proton Induced X-ray Emission (PIXE) was employed to measure simultaneously the concentration of 12 trace elements in the hair of 141 AGA newborn infants at term. Log-normal distributions were measured for all elements. There were no significant differences in trace elements in relation to sex, gestational age and body weight. The geometric means (mg/kg) were: Cr, 1.5 +/- 0.2; Mn, 1.5 +/- 0.1; Fe, 51 +/- 4; Ni, 1.0 +/- 0.2; Cu, 6.1 +/- 0.3; Zn, 133 +/- 3; As, 0.055 +/- 0.005; Se 0.81 +/- 0.05; Br, 1.3 +/- 0.1; Pb, 1.4 +/- 0.2; Rb, 0.22 +/- 0.03; and Sr, 1.5 +/- 0.2. Some direct and inverse partial correlations among elements were found at different levels of significance. Each element was significantly correlated with at least one other. Zinc and copper concentrations were lower compared to data in the literature. The high values of chromium and selenium concentrations were in agreement with previous findings. The manganese level was in accordance with previous data. The Zn/Cu ratio agreed very well with the data in the literature. This indicates that while concentration values may be subjected to large variations due to living conditions, correlations could be more stable and therefore offer insight on the regulatory mechanisms governing trace element metabolism in man.
Copper↗
Antioxidation activity of tetrahydrobiopterin in pheochromocytoma PC 12 cells.
Rat pheochromocytoma PC 12 cells are susceptible to the oxidative toxicity caused by H2O2, nitrofurantoin, dopamine, and xanthine/xanthine oxidase reaction. The cytotoxicities of these agents are greatly reduced by the simultaneous presence of 0.1 mM tetrahydrobiopterin (BH4), 3 units/ml horseradish peroxidase, 0.2 mM NADH, and 0.1 units/ml sheep liver dihydropteridine reductase (DHPR). Individually, BH4, NADH and DHPR have no protection against H2O2 toxicity in PC 12 cells. Peroxidase alone offers 58% of protection if cells are incubated in the medium but only 3% in Dulbecco's phosphate buffered saline. The efficiency of the BH4-mediated antioxidation system in PC 12 cells is equal to or better than ascorbic acid and catalase, depending on the source of the reactive O2 species (ROS). The reactions responsible for the BH4-antioxidation system may consist of the non-enzymatic and the peroxidase-catalyzed reduction of H2O2 to H2O by BH4 and the regeneration of BH4 by DHPR using NADH as the cofactor. The components of this defence mechanism against ROS are all normal cellular constituents and are ubiquitous in nature. This DHPR-catalyzed redox cycling of BH4 may constitute an as yet little-known antioxidation system in mammalian cells.
Adrenal Gland Neoplasms↗
In vitro activity of sparfloxacin.
Sparfloxacin, a new fluoroquinolone, inhibited the majority of members of the family Enterobacteriaceae at less than or equal to 1 microgram/ml. It was less active than ciprofloxacin but more active than ofloxacin. Against Pseudomonas aeruginosa, it was less active than ciprofloxacin but twofold more active than ofloxacin. It inhibited Staphylococcus aureus and most Streptococcus pneumoniae and Streptococcus pyogenes isolates at 0.25 micrograms/ml, whereas ciprofloxacin and ofloxacin inhibited these isolates at 2 micrograms/ml. Bacteroides fragilis was inhibited by less than or equal to 2 micrograms/ml. Sparfloxacin was less active at an acidic pH and in the presence of Mg2+. Resistance to sparfloxacin was produced by repeated exposure, although the frequency of single-step mutants was less than 10(-9).
Anti-Infective Agents↗
[Preparation of rotundine-chitosan gelled granules and their drug-release tests].
The paper described a delivery system prepared from granulation of a chitosan solution containing rotundine in a coagulating bath and examined the effects of the ratios of rotundine: chitosan, crosslinking agents and molecular weight of chitosan on the analgesic release rate. It was shown that the rotundine (56.7%)-chitosan (Mw:5.70 x 10(5) degree of deacetylation: 72.4%) gelled granules in an artificial gastroenteric juice (pH 1.0 and 7.2) have T50 of 40 and 180 min respectively, and the total release time sustained over 540 min.
Alkaloids↗