Biomedical subjects

T Ning

Publications and source records attributed to T Ning.

12 recordsLinked to original sources

PubMed2000

Intestinal inflammation observed in IL-2R/IL-2 mutant mice is associated with impaired intestinal T lymphopoiesis.

BACKGROUND & AIMS: Although interleukin (IL)-2(-/-) and IL-2Ralpha(-/-) mice develop inflammatory bowel disease, IL-2Rbeta(-/-) animals are apparently free of gut pathology. Intraintestinal T lymphopoiesis is reported to be impaired in IL-2Rbeta(-/-) mice; we have determined whether this characteristic correlated with the apparent resistance of this mutant strain to intestinal inflammation. This led us to reassess intraintestinal T lymphopoiesis in these 3 mutant strains. METHODS: Intestinal histology and intraintestinal T lymphopoiesis were analyzed in unmanipulated mutant mice and in athymic and euthymic radiation chimeras reconstituted with bone marrow derived from IL-2(-/-), IL-2Ralpha(-/-), and IL-2Rbeta(-/-) donors. RESULTS: Intraintestinal T lymphopoiesis was ablated in the 3 mutant strains and was associated with cryptopatch abnormalities. The intestinal mucosa of mice reconstituted with lymphocytes from IL-2Rbeta(-/-) mice exhibited lesions of both the small and large bowel similar to those observed in the early stages of human gluten enteropathy and acute ulcerative colitis, respectively. Analysis of euthymic and athymic bone marrow radiation chimeras indicated that T cells located in the intestinal mucosa of unmanipulated IL-2(-/-), IL-2Ralpha(-/-), and IL-2Rbeta(-/-) mice are of thymic origin. CONCLUSIONS: Null mutations at IL-2/IL-2Ralpha and beta loci differentially affect intraintestinal and intrathymic T lymphopoiesis. These conditions are associated with lesions of intestinal inflammation that are mediated by thymus-derived T cells.

Animals↗

PubMed1998

[Studies of microsatellite instability in Chinese gastric cancer tissues].

OBJECTIVE: To identify the microsatellite instability(MSI) rates in Chinese gastric cancer samples. METHODS: 29 microsatellite markers were selected to examine 42 paired gastric cancer tissues for MSI on all chromosomes except Y. RESULTS: The total frequency of MSI in all 42 gastric cancers was 33.9% with higher rates at loci of D3S1577, D3S1067,D8S279,D9S257, D1S248, D7S520 and D2S147,and the highest rate at D3S1577 and D3S1067(51.35%). MSI varied with different pathological types. The frequencies of MSI were signi- ficantly higher in poorly differentiated tumors and signet cell types, compared with well differentiated tumors(P=0.0026 and 0.0013 by chi-square test),and no difference was noted between poorly differentiated and signet cell types. CONCLUSION: MSI may play an important role in Chinese gastric cancer, particularly the poorly differentiated adenocarcinomas. The data presented here further support the previous hypothesis that pathologically distinct subtypes of gastric cancer undergo different genetic pathways during tumorigenesis.

Adult↗

PubMed1996

[Micronucleus effect induced by Helicobacter pylori on human gastric mucous epithelial membrane].

A large number of data from epidemiologic and statistical studies showed there was a relationship between infection of Helicobacter pylori (Hp) and gastric carcinogenesis, but its mechanism was unclear. Micronucleus test in vitro, one of cytogenotoxic studies, was carried out to study mutagenicity of Hp. Results showed micronucleus formation in gastric mucous epithelial membrane cell GES-1 treated with ultra-sonicated Hp for 72 hours was significantly greater than in the negative controls. There existed a dose-response relationship between them when concentration of Hp reached a range of 0.3-1.7 mg/L. As concentration of Hp reached 1.7 mg/L, percentage of micronucleus formation was five times higher than that of controls. When concentration of Hp increased to 4.3 to 10.7 mg/L, micronucleus formation did not increase but it was still over two times higher than that in controls. It suggests that there exists a direct cytogenotoxic effect of Hp on human gastric mucous epithelial membrane.

Epithelium↗

PubMed1996

[Glucocorticoid-induced apoptosis of human gastric epithelial cells transfected with p53 genes].

To investigate the apoptosis-inducing effect of glucocorticoid on gastric epithelial cell expressing different p53 genes, a human gastric epithelial cell line-GES-1 was transfected with either wild type or mutant p53 cDNA in vitro. The cells were treated with hydrocortisone in a concentration range of 0.2-0.8 g/L. Apoptotic cells were found in those transfectants. The apoptotic response of the wild-type p53-transfected GES-1 cells was much more marked than that of the mutant p53 transfected ones. It can be inferred that the glucocorticoid secreted not only suppress the immunological response during inflammation, but induce gastric epithelial cell apoptosis as well. If the gastric epithelial cell contains mutant p53 genes, the glucocorticoid confer a selective growth advantage which advance the malignant process.

Apoptosis↗

PubMed1995

Chloride is required for receptor-mediated divalent cation entry in mesangial cells.

Agonists which stimulate the inositol 1,4,5 trisphosphate ([1,4,5]-IP3)-dependent mobilization of Ca2+ from intracellular stores also stimulate entry of divalent cations across the cell membrane. Under appropriate experimental conditions, divalent cation entry across the cell membrane can be monitored as the rate at which the intracellular fluorescence of divalent cation indicators is quenched by the addition of Mn2+ to the extracellular medium. We report that addition of vasopressin to fura-2-loaded glomerular mesangial cells in culture markedly accelerated the rate at which Mn2+ quenched fura-2 fluorescence at its Ca(2+)-insensitive wavelength in the presence of extracellular NaCl, but that this quench response was attenuated when Cl- was removed from the extracellular medium by equimolar substitution with impermeant anions (gluconate, methanesulfonate, acetate, lactate). Similarly, loss of agonist-induced quench also occurred when Cl- was substituted with gluconate in K(+)-containing media. Addition of the Cl- channel inhibitor, 5-nitro-2-(3-phenylpropylaminobenzoic acid) (NPPB), also inhibited Mn(2+)-induced quench of fura-2 fluorescence following vasopressin addition. In contrast, in the presence of gramicidin to provide an alternate conductance pathway to accompany divalent cation entry, agonist-dependent Mn2+ quench occurred even in the absence of extracellular Cl-, indicating that the requirement for Cl- was not the result of cotransport on a common transporter nor the result of Cl- serving as a necessary cofactor for divalent cation entry. A similar dependence on extracellular Cl- was observed for other Ca(2+)-mobilizing agonists such as endothelin, as well as the intracellular Ca2+ ATPase inhibitor, thapsigargin. Extracellular Cl- dependence for agonist-induced divalent cation entry was also reflected in a corresponding extracellular Cl- dependence for agonist-induced mesangial cell contraction. It has been previously shown by ourselves (Kremer et al., 1992a, Am. J. Physiol., 262:F668-F678) and others that agonist-stimulated calcium mobilization in mesangial cells is accompanied by inhibition of K+ conductance and increased Cl- conductance. Accordingly, we conclude that the current findings suggest that activation of Cl- conductance provides regulated charge compensation for receptor-mediated divalent cation entry in response to Ca(2+)-mobilizing vasoconstrictor agonists in mesangial cells.

Animals↗

PubMed1994

Effects of sterigmatocystin and T-2 toxin on the induction of unscheduled DNA synthesis in primary cultures of human gastric epithelial cells.

Primary cultures of human gastric epithelial cells were tested for induction of unscheduled DNA synthesis (UDS) by sterigmatocystin (ST) and T-2 toxin. Autoradiographic results indicated that ST (10(-6)-10(-4)M) induced UDS in the presence of S9 activation system. The repair rates were 24-91% (net grains > or = 3) and 2-71% (net grains > or = 5). T-2 toxin did not induce UDS in this study.

Animals↗

PubMed1994

[Establishment and characterization of a SV40 transformed human fetal gastric epithelial cell line-GES-1].

9 month human fetal gastric epithelial cells were primarily cultured and infected with SV40 virus. About 3 weeks after infection the transformed-like cells showed up and were isolated when most of the normal cells senesced. One transformed clone named GES-1 were analyzed biologically. The results indicated integration of the SV40 T gene and its expression in the cell nuclei and the cells became hyperploid in chromosomes. This cells also maintained a normal cytoskeleton, positive in PAS reaction and were non-tumorigenic in nude mice. The established cell line may be served as an important model system in study of human gastric carcinogenesis.

Animals↗

PubMed1993

Nonlinear analysis of the hippocampal subfields of CA1 and the dentate gyrus.

The paper discusses the use of nonlinear bispectral analysis in examining the hippocampal EEG collected at subfields of CA1 and the dentate gyrus during the vigilance state of REM sleep. The cross-bispectrum and its unique capabilities of detecting and quantifying quadratic nonlinear interactions occurring between these two hippocampal subfields are explained and demonstrated with simulation examples and EEG data. It was found in this study that quadratic nonlinear interactions exist between CA1 and the dentate gyrus in the 6-8 frequency band which dominates the theta (theta) rhythm observed in the hippocampal EEG during REM sleep. As a result, energy components around the frequency band of the second-order harmonics of theta rhythm are not totally spontaneous, but generated largely due to quadratic nonlinear interactions.

Analog-Digital Conversion↗

PubMed1990

[Effects of alcohol extract from Polygonatum odoratum (Mill.) Druce and Cuscuta australis R. Br. on immunological function of mice injured by burns].

This paper shows that the alcoholic extract from Polygonatum odoratum and Cuscuta australis increases the percentage of phagocytosis and the index of phagocytosis of macrophages as well as hemolysin and proliferation of lymphocytes up to normal level in mice with II+ burn injury covering 5% body surface. It follows that both Polygonatum odoratum and Cuscuta australis may serve as a kind of immunopotentiator for mammals.

Adjuvants, Immunologic↗

PubMed1987

Advanced signal-processing method for the detection, localization, and quantification of acute myocardial ischemia.

In this study of a canine heart model of localized reversible ischemia, a computer-based single-processing method is developed to detect and localize the epicardial projections of ischemic myocardial electrocardiograms (ECGs) during the cardiac activation, rather than the repolarization, phase. This is done by transforming ECG signals from an epicardial sensor array into the multichannel spectral domain and identifying three decision variables: (1) the frequency in hertz of the spectral peak (f0), its frequency band width 50% below the peak value (w0), and the maximum eigenvalue difference of the ECG signal's autocorrelation matrix (e0). With use of the histograms of the f0, w0, and e0 parameters of 3256 ECGs from normal and 957 from ischemic areas of myocardium obtained from 12 dogs, it was possible to predict ischemia in a new test group of nine animals from a Neyman-Pearson (NP) test in which the threshold probabilities of detecting ischemia for each decision variable are compared with those of detecting normality. Quantification of each sensor area by the NP tests revealed that, compared with the control, ECG spectra with decreased F0 and w0 and increased e0 relative to their respective thresholds had increased myocardial lactate (p less than 0.01), decreased adenosine triphosphate (ATP) (p less than 0.05), and reduced creatine phosphate (p less than 0.01). Prediction of f0 (p less than 0.0006) as a continuous variable could be obtained from the regression of the myocardial levels of ATP plus creatine phosphate, which demonstrated that this decision variable appears to directly reflect myocardial energetics. It appears that an advanced signal-processing method for ECG array data can be used to detect, localize, and quantify reversible myocardial ischemia.

Adenosine Triphosphate↗

PubMedDate not supplied

The efficacy of intramuscular ketorolac in combination with intravenous PCA morphine for postoperative pain relief.

STUDY OBJECTIVE: To examine the efficacy of intramuscular (IM) ketorolac used in combination with intravenous (IV) patient-controlled analgesia (PCA) morphine for postoperative pain relief following intra-abdominal gynecologic surgery. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Patient care unit at a university medical center. PATIENTS: Thirty-five healthy women undergoing intra-abdominal gynecologic surgery who requested postoperative PCA. INTERVENTIONS: Postoperatively, all patients received IV PCA morphine, with the PCA device programmed to deliver a maximum of 1 mg every 6 minutes (maximum of 30 mg over 4 hours). In addition, patients received one of three regimens: (1) IM saline every 6 hours; (2) IM ketorolac 30 mg while in the postanesthesia care unit (PACU), followed by 15 mg every 6 hours; or (3) IM ketorolac 60 mg while in the PACU, followed by 30 mg every 6 hours. MEASUREMENTS AND MAIN RESULTS: Patients were assessed at regular intervals. Visual analog scale (VAS) scores were used to assess analgesia and patient satisfaction with therapy. Data on morphine usage were obtained from the PCA device, and the frequency and severity of adverse effects were assessed for the presence or absence of side effects. Cumulative morphine dosages were lower (p less than 0.05) in both ketorolac groups at 12, 18, and 24 hours. VAS scores and the frequency of side effects did not differ significantly among groups. CONCLUSIONS: IM ketorolac significantly decreased PCA morphine requirements. The analgesic effects of the two drugs appear to be additive.

Adult↗

PubMedDate not supplied

Quadratic phase coupling as a quantitative measure for the developing hippocampal formation.

This paper presents the bispectral analysis of the ontogeny of the hippocampal EEG recorded from the dentate gyrus and CA1, the primary sites that generate theta (theta) rhythm. The hippocampal EEG was collected during the vigilance state of rapid eye movement (REM) sleep of freely moving rats at 15, 30 and 90 days of age. In previous studies we demonstrated through bispectral analysis that significant quadratic phase coupling (QPC) of the EEG exists in the hippocampal formation of CA1 and the dentate gyrus during REM sleep, primarily in the theta (4-11 Hz) frequency range. In the present study we have examined whether QPC can be used as an effective measure of development, i.e., maturation of the hippocampal subfields CA1 and the dentate gyrus. We found that as animals mature from the age of 15 to 90 days, the occurrence of nonlinear QPC activities moves from (6.25 Hz, 6 Hz) to (7 Hz, 7 Hz) at CA1 and (6 Hz, 6 Hz) to (7.5 Hz, 7.5 Hz) at the dentate gyrus, respectively. The results indicate that bispectral analysis provides an additional and important description of the frequency characteristics of the hippocampal EEG and that the QPC measure is also a useful index to quantify the shift in the hippocampal theta frequency as animals mature.

Animals↗