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Biomedical subjects

X Peng

Publications and source records attributed to X Peng.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Intestinal blood perfusion improved by early enteral feeding in burned rat].

OBJECTIVE: To explore the mechanism of intestinal blood perfusion improved by early enteral feeding after burn injury. METHODS: Wistar rats were inflicted with 30% total body surface area full thickness flame burn and randomly divided into three groups: burned control (B), burned and early feeding (EF), and normal control (C). The content of endothelin (ET), nitric oxide (NO), vasoactive intestinal peptide (VIP), and intestine mucosal blood flow (IMBF) were determined at postburn 0, 3, 6, 12, 24, 48 hours. RESULTS: The content of ET, NO, VIP in small intestine as well as the ratio of ET/NO, ET/VIP were increased significantly and the IMBF was decreased markedly postburn. In EF group, ET, ET/NO and ET/VIP were significantly lower (P < 0.05, P < 0.01), and NO, VIP as well as IMBF were higher than those in B group (P < 0.05, P < 0.01). There were negative correlation between ET/NO, ET/VIP and IMBF (r(1) = -0.95, P < 0.01; r(2) = -0.87, P < 0.01). CONCLUSIONS: The mechanism of intestinal blood perfusion improved by early enteral feeding may be correlated with increased NO, VIP and decreased ET induced by foods stimulating intestinal nerve.

Animals↗
PubMed1999

[Antihypertensive study of xingnao qingxuan recipe].

OBJECTIVE: To observe the effect of decreasing blood pressure of Xingnao Qingxuan Casuples. METHOD: The blood pressure in normal and anesthetised cats was examined with direct method, the blood pressure in the conscious SHR was obtained by indirect method. RESULTS: Duodenuos administration(id) of XQC of 2.8 g/kg produced a decrease of blood pressure in normal cats; XQC of 1.4, 2.8 and 5.6 g/kg once a day for 14 days produced a dose-dependent reduction of blood pressure in SHR, 3-4 days after administration the blood pressure returned to the level before but the change was not significant. With gastric administration of XQC of 2.8 and 5.6 g/kg for 3 times, the incubation period of eyeball tremor induced by chloroform by dropping into the ear was prolonged by 14.4% and 13.0%, and the keeping time shortened by about 33.3% and 23.3% respectively. Brain basic arterial spasm induced by KCl or 5-HT in dog was relaxed obviously by XQC in vitro experiment. CONCLUSION: XQC has the effect of reducing blood pressure resisting dizziness, which is related to the diastole of brain blood vessel.

Animals↗
PubMed1999

[Effection of children airway foreign bodies on blood acid-base disturbances].

OBJECTIVE: To explore the effects of children airway foreign bodies on blood acid-base disturbances. METHOD: To detect the blood-gas and electrolyte of 50 cases by children airway foreign bodies (test group), they were compared with 50 cases normal children (control group). To calculate anion gap (AG), to determine types of acidbase disturbances. RESULT: The blood-gas and K+ were significant difference between that two groups. In the test group, there were 25 simple and 19 mixed acid-base disturbances; 6 acid-base balances. There were 31 high AG, 18 normal AG, one low AG. CONCLUSION: Children airway foreign bodies can cause acid-base disturbances. It was major in simple metabolic acidosis and mixed metabolic acidosis with respiratory alkalosis, it was more in high AG-metabobic acidosis.

Acid-Base Imbalance↗
PubMed1999

[Epidemiological survey on orchard pollinosis].

OBJECTIVE: To investigate the prevalence of Orchard Pollinosis in China. METHOD: From 1995 to 1998, an epidemiological survey on orchard pollinosis was carried on among 1,660 primary and middle school students and 2,167 university students, including questionnaire investigation, nasal inspection and scratch test. From April to June of 1998, a clinical investigation of orchard pollinosis was adopted among 30 patients of allergic rhinitis including scratch test and nasal mucosa test. RESULT: 1. The total positive rate of orchard pollen scratch test was 6.7%, and the prevalence of orchard pollinosis was 0.37%. 2. 5 cases (16.7%) were hypersensitive to orchard pollen clinically in allergen test. CONCLUSION: Orchard pollinosis is one kind of important pollinosis and should be paid high attention to.

Adolescent↗
PubMed1999

[A study on ovariectomized goat osteoblast culture in vitro].

Osteoblasts were isolated from the frontal parietal bone of ovariectomized goat and were confirmed by testing for multiple biological features. The results showed that the goat osteoblasts cultured had the typical morphological feature of osteoblasts, the activity of alkaline phosphatase, and the ability of calcification in vitro. Also, the results proved that these goat osteoblasts in vitro had the same function and features as those in vivo. The experimental techniques in this study have provided a useful system for researches in bone metabolism.

Alkaline Phosphatase↗
PubMed1999

[The hydrogen bond between 5-(2-carboxyphenyl)-10, 15, 20-triphenylporphyrin and amino acid ester--study with UV-Vis titration and 1H-NMR].

The hydrogen bonds between the hydrogen of pyrrols in 5-(2-carboxyphenyl)-10,15,20-triphenylporphyrin and the oxygen of the carboxyl group of amino acid ester were confirmed by UV-Vis spectroscopic titration method and 1H-NMR. When amino acid ester was added to o-TPPCO2H solution in CHCl3, the Soret and Q and red-shifted dramatically and several isobestic points could be observed in UV-Vis spectra. In 1H-NMR, the signal of the hydrogen atoms of pyrrole in o-TPPCO2H (-2.78 ppm) decreased and a new signal in 0.260 ppm emerged, when o-TPPCO2H mixed with L-PheOEt at 1 : 1 (mol/mol).

Amino Acids↗
PubMed1998

Identification of a membrane-associated inhibitor(s) of epidermal growth factor-induced signal transducer and activator of transcription activation.

Many growth factors, including epidermal growth factor (EGF), can activate the signal transducer and activator of transcription (STAT) signaling pathway. Here, we demonstrate that STAT activation by EGF treatment is conditional. EGF activates STAT1 and STAT3 in A431 but not in HeLa and PC12 cells. Using a reconstituted in vitro STAT activation system, we have identified and partially purified a potential inhibitor (s) that is membrane-associated and can block STAT activation induced by EGF in vitro. However, this inhibitor has no effect on STAT complexes after they are formed. We have further shown that this inhibitor(s) also exists in many other cancer cell lines, suggesting that blocking the STAT activation during growth factor signal transduction may play a significant role in the development of many kinds of cancers.

Animals↗
PubMed1998

Pertussis toxin-sensitive G proteins influence nitric oxide synthase III activity and protein levels in rat heart.

Inhibitory G protein activity (Gi) and nitric oxide (NO) modulate muscarinic-cholinergic (MC) inhibition of cardiac beta-adrenergic inotropic responses. We hypothesized that Gi mediates MC-NO synthase (NOS) signal transduction. Isoproterenol (0.2-0.8 microg/min) and acetylcholine (1 microM) were administered to isolated perfused rat hearts pretreated with saline (controls; n = 8) or pertussis toxin (PT; 30 microg/kg intraperitoneally 3 d before study; n = 20). PT abrogated in vitro ADP-ribosylation of Gi protein alpha subunit(s) indicating near-total decrease in Gi protein function. Isoproterenol increased peak +dP/dt in both control (peak isoproterenol effect: +2, 589+/-293 mmHg/s, P < 0.0001) and PT hearts (+3,879+/-474 mmHg/s, P < 0.0001). Acetylcholine reversed isoproterenol inotropy in controls (108+/-21% reduction of +dP/dt response, P = 0.001), but had no effect in PT hearts. In controls, NG-monomethyl-L-arginine (100 microM) reduced basal +dP/dt, augmented isoproterenol +dP/dt (peak effect: +4,634+/-690 mmHg/s, P < 0.0001), and reduced the MC inhibitory effect to 69+/-8% (P < 0.03 vs. baseline). L-arginine (100 M) had no effect in controls but in PT hearts decreased basal +dP/dt by 1, 426+/-456 mmHg/s (P < 0.005), downward-shifted the isoproterenol concentration-effect curve, and produced a small MC inhibitory effect (27+/-4% reduction, P < 0.05). This enhanced response to NO substrate was associated with increased NOS III protein abundance, and a three- to fivefold increase in in vitro calcium-dependent NOS activity. Neomycin (1 microM) inhibition of phospholipase C did not reverse L-arginine enhancement of MC inhibitory effects. These data support a primary role for Gi in MC receptor signal transduction with NOS in rat heart, and demonstrate regulatory linkage between Gi and NOS III protein levels.

Acetylcholine↗
PubMed1998

IL-12 up-regulates CD40 ligand (CD154) expression on human T cells.

IL-12 is a heterodimeric cytokine produced by APC that promotes the development of CD4+ Th1 cells and their IFN-gamma production after TCR/CD3 triggering. We here investigated the capacity of IL-12 to modify the expression on T cells of CD40 ligand (CD40L or CD154), a molecule transiently expressed on activated T cells and known to be of utmost importance for cognate interaction with B cells and for activation of dendritic cells and macrophages. Our data demonstrate that IL-12 up-regulates CD40L expression on anti-CD3-activated human peripheral blood T cells. For optimal induction of CD40L, IL-12 synergizes with IL-2 as well as with other costimulatory interactions, such as B7/CD28. The effect of IL-12 was observed at both the protein and the mRNA level. T cells costimulated by IL-12 provided more efficient help for IL-4-dependent B cell proliferation and for IgG production than when activated in the absence of IL-12. This helper activity was blocked by an mAb against CD40L, indicating that the effect of IL-12 on B cells is mediated indirectly through CD40L. The data thus suggest that the effects of IL-12 on cellular and humoral immune responses are partly mediated through CD40L induction.

3T3 Cells↗
PubMed1998

Cyclosporin A increases IFN-gamma production by T cells when co-stimulated through CD28.

Despite its calcineurin-inhibiting properties, cyclosporin A (CsA) can not inhibit IL-2 production when T cells are co-stimulated by CD80/CD86 on the antigen-presenting cells. We studied the in vitro effect of CsA on IFN-gamma production. Anti-CD3 monoclonal antibody (mAb) was used as the primary stimulus for activation of purified human T cells. A stimulating anti-CD28 mAb, or CD80 or CD86 on stably transfected P815 cells, provided the co-stimulatory signal. IL-2 production was hardly affected by CsA under these stimulating conditions, while IFN-gamma (at the protein and mRNA level) was markedly stimulated by CsA. The use of anti-CD3 or phorbol 12-myristate 13-acetate with ionomycin as the primary stimulus, together with costimulation through either CD28 or CD2 using transfectants with the appropriate ligands, allowed us to demonstrate that the resistance of IFN-gamma production to inhibition by CsA required both CD3 and CD28 triggering. Inhibition of IL-10 production, and to a lesser degree of IL-4 production, by CD4+ cells was responsible for the enhancement of IFN-gamma production in the presence of CsA. In conclusion, IFN-gamma production by CD28-co-stimulated CD4+ T cells is resistant to inhibition by CsA and can even be facilitated by CsA as a result of removing a negative regulatory signal which is mainly IL-10 mediated. This finding might have implications for immunosuppressive strategies based upon the use of CsA.

Adjuvants, Immunologic↗
PubMed1998

Smoking and the development of Warthin's tumour of the parotid gland.

The smoking history was surveyed in 160 consecutive patients with Warthin's tumour of the parotid gland in order to investigate the relationship between smoking and the development of this tumour. Two hundred cases of middle-aged or elderly normal persons and 163 consecutive patients with pleomorphic adenoma in the parotid gland served as controls. The percentage of smoking in patients with Warthin's tumour (96.3%) was much higher than that of middle-aged or elderly normal persons (25.5%) and in patients with pleomorphic adenoma (26.4%). Moreover, the amount of smoking was greater and the smoking history was longer in patients with Warthin's tumour. When the male and female patients were analysed respectively, the same result was shown. This case-control study suggests that smoking may be one of the aetiologic factors associated with the development of Warthin's tumour.

Adenolymphoma↗
PubMed1998

Effects of anti-IL-4 receptor monoclonal antibody on in vitro T cell cytokine levels: IL-4 production by T cells from non-atopic donors.

IL-4 is a pleiotropic cytokine which is involved in the development of atopic diseases. Only limited data exist on IL-4 production in humans, and the relative contribution to atopy of either unbalanced IL-4 production, or increased IL-4-responsiveness of target cells, is still unknown. The use of a MoAb to the IL-4 receptor alpha-chain (IL-4Ralpha) enabled us to demonstrate that IL-4 production in vitro is usually underestimated, due to in vitro consumption, even in cultures of purified T cells. When IL-4 consumption was blocked, it became evident that CD80 and CD86 both provide effective costimulatory signals for high IL-4 production. Moreover, we found that even stimulation with a soluble antigen (tetanus toxoid) induces IL-4 production by T cells from healthy non-atopic donors. Both sets of data imply that IL-4 is not required for IL-4 production by memory and/or effector T cells. Our data further show that endogenous IL-4 activity modulates IL-10 and interferon-gamma production by T cells in opposite directions. The use of this receptor-blocking antibody will thus be helpful for in vitro studies on IL-4 regulation. Consumption of IL-4 by different cell types during in vitro cultures might have interfered with previous attempts to quantify IL-4 production by human T cells.

Adult↗
PubMed1998

Cloning of a Sphingomonas paucimobilis SYK-6 gene encoding a novel oxygenase that cleaves lignin-related biphenyl and characterization of the enzyme.

Sphingomonas paucimobilis SYK-6 transforms 2,2'-dihydroxy-3,3'-dimethoxy-5,5'-dicarboxybiphenyl (DDVA), a lignin-related biphenyl compound, to 5-carboxyvanillic acid via 2,2',3-trihydroxy-3'-methoxy-5,5'-dicarboxybiphenyl (OH-DDVA) as an intermediate (15). The ring fission of OH-DDVA is an essential step in the DDVA degradative pathway. A 15-kb EcoRI fragment isolated from the cosmid library complemented the growth deficiency of a mutant on OH-DDVA. Subcloning and deletion analysis showed that a 1.4-kb DNA fragment included the gene responsible for the ring fission of OH-DDVA. An open reading frame encoding 334 amino acids was identified and designated ligZ. The deduced amino acid sequence of LigZ had 18 to 21% identity with the class III extradiol dioxygenase family, including the beta subunit (LigB) of protocatechuate 4,5-dioxygenase of SYK-6 (Y. Noda, S. Nishikawa, K.-I. Shiozuka, H. Kadokura, H. Nakajima, K. Yano, Y. Katayama, N. Morohoshi, T. Haraguchi, and M. Yamasaki, J. Bacteriol. 172:2704-2709, 1990), catechol 2,3-dioxygenase I (MpcI) of Alcaligenes eutrophus JMP222 (M. Kabisch and P. Fortnagel, Nucleic Acids Res. 18:3405-3406, 1990), the catalytic subunit of the meta-cleavage enzyme (CarBb) for 2'-aminobiphenyl-2,3-diol from Pseudomonas sp. strain CA10 (S. I. Sato, N. Ouchiyama, T. Kimura, H. Nojiri, H. Yamane, and T. Omori, J. Bacteriol. 179:4841-4849, 1997), and 2,3-dihydroxyphenylpropionate 1,2-dioxygenase (MhpB) of Escherichia coli (E. L. Spence, M. Kawamukai, J. Sanvoisin, H. Braven, and T. D. H. Bugg, J. Bacteriol. 178:5249-5256, 1996). The ring fission product formed from OH-DDVA by LigZ developed a yellow color with an absorption maximum at 455 nm, suggesting meta cleavage. Thus, LigZ was concluded to be a ring cleavage extradiol dioxygenase. LigZ activity was detected only for OH-DDVA and 2,2',3,3'-tetrahydroxy-5,5'-dicarboxybiphenyl and was dependent on the ferrous ion.

Amino Acid Sequence↗
PubMed1998

Detection and sequence analysis of borna disease virus p24 RNA from peripheral blood mononuclear cells of patients with mood disorders or schizophrenia and of blood donors.

Borna disease virus (BDV) p24 RNA was detected in the peripheral blood mononuclear cells (PBMCs) of psychiatric patients and blood donors by nested reverse transcriptase PCR (RT-PCR). The prevalences of BDV p24 RNA in patients with mood disorders (4%) and schizophrenia (4%) were not significantly different from that in blood donors (2%). This finding was inconsistent with previous reports that showed either a high prevalence or absence of BDV p24 RNA in patients with psychiatric disorders. The differences in BDV p24 RNA prevalence in these studies may be due to differences in the criteria for positivity, the number of PBMCs used for RNA extraction, or the amount of RNA tested for nested RT-PCR or to laboratory contamination. Sequence analysis of BDV p24 RNA from the PBMCs of patients and blood donors showed a high nucleotide sequence conservation but definite nucleotide mutations compared with horse BDV p24 RNA sequences. In comparison with human BDV p24 RNA sequences previously reported from Japan and Germany, there were several positions with silent nucleotide mutations among these clones.

Adult↗
PubMed1998

Factors regulating SCC antigen expression in squamous cell carcinoma of the uterine cervix.

Expression of squamous cell carcinoma (SCC) antigen emerged concurrently with squamous formation of the uterine cervix and increased during the neoplastic transformation of the cervical squamous epithelium. SCC antigen expression differed considerably among the histomorphologic cell types of cervical carcinoma. Large cell nonkeratinizing carcinoma contained high levels of the antigen. In contrast, no appreciable expression of SCC antigen was observed in small cell nonkeratinizing carcinoma. The pattern of SCC antigen expression closely coincided with EGF receptor (EGF-R) expression in cervical squamous neoplasia. This suggests that the expression of SCC and EGF-R in cervical carcinoma is related to the differentiation or dedifferentiation processes of the tumor cells. SCC production by CaSki cervical epidermoid carcinoma cells was stimulated by EGF. It seems likely that an autocrine system, in which EGF serves as the signal, may exist in cervical squamous carcinoma. 17beta-estradiol and L-triiodothyronine were found to upregulate EGF-R expression, proliferative potential and SCC production in the CaSki cervical carcinoma cells.

Antigens, Neoplasm↗
PubMed1998

Serum deprivation-induced apoptosis in cultured porcine granulosa cells is characterized by increased expression of p53 protein, Fas antigen and Fas ligand and by decreased expression of PCNA.

Although serum deprivation induces apoptosis in several cell lines, biochemical characterization of the apoptosis in primary granulosa cells (GCs) induced by serum deprivation has rarely been reported. In the present study, GCs from small follicles of porcine ovaries were precultured under a serum-containing condition for seven days, then stepped down to a serum-free condition and cultured for the subsequent two days. GCs were subjected to DNA fragmentation and immunoblot analyses. Data indicated that serum deprivation induced GC apoptosis characterized by DNA laddering, which was associated with decreased expression of proliferating cell nuclear antigen (PCNA) and increased expression of p53 protein, Fas antigen and Fas ligand. Serum deprivation also resulted in an increase in a 115 kDa protein expression despite no detectable expression of a 66 kDa c-myc protein. This suggests that serum removal from primary GCs may activate multiple apoptotic pathways such as a p53-associated pathway and a Fas-Fas ligand pathway.

Animals↗