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S Z Liu

Publications and source records attributed to S Z Liu.

At least 19 recordsLinked to original sources
PubMed2003

Association study of neuregulin 1 gene with schizophrenia.

A number of studies have indicated that 8p22-p12 is likely to harbor schizophrenia susceptibility loci. In this region, the candidate gene of interest, neuregulin 1 (NRG1), may play a role in the pathogenesis of schizophrenia. Then in the present study, we performed the linkage disequilibrium to determine the association between three genetic variants (SNPs: rs3924999, rs2954041, SNP8NRG221533) on NRG1 gene and schizophrenia in 246 Chinese Han schizophrenic family trios using PCR-based restriction fragment length polymorphism method and denaturing high-performance liquid chromatography. The transmission disequilibrium test analysis for each variant showed a significant difference between two transmitted alleles even after Bonferroni correction (rs3924999, P=0.007752; rs2954041, P=0.0009309; SNP8NRG221533, P=0.012606). The global chi(2) test for haplotype transmission also revealed a strong association (chi(2)=46.068, df=7, P&<0.000001). Our results suggest that the NRG1 gene may play a role in conferring susceptibility to the disease.

Adult↗
PubMed2002

Quantification of glyceryl trinitrate effect through analysis of the synthesised ascending aortic pressure waveform.

OBJECTIVE: To establish through analysis of the radial pressure pulse waveform the dose dependent effects of glyceryl trinitrate (GTN) on properties of different blood vessels. DESIGN: Radial pulse waveform was measured in randomised order before, during a five hour application of a GTN patch delivering 0.104-0.625 mg/h, and for two hours after patch removal. The radial pressure waveform (Millar applanation tonometer) was convolved into an ascending aortic wave using a generalised transfer function (SphygmoCor process) enabling measurement of aortic systolic, diastolic, pulse, mean, and augmented pressure and left ventricular ejection duration in addition to standard brachial cuff pressures. SETTING: Fu Wai and Ren Ming hospitals in Beijing, China. PATIENTS: 46 recumbent hospitalised patients aged 56 (9) years, awaiting electrophysiological or other diagnostic studies, fasting, and with other treatments suspended. MAJOR OUTCOME MEASURES: Conventional brachial pressure measures and data from the synthesised aortic pulse. RESULTS: There was no consistent change in heart rate or brachial pressures except for a decrease in systolic and pulse pressures (p < 0.01) at dose > 0.416 mg/h. In contrast, there were substantial and significant (p < 0.0001) decreases in aortic systolic, pulse, and augmented pressures at all doses, mean pressure (p < 0.001) at doses > 0.416 mg/h, and ejection duration (p < 0.001) at doses > 0.208 mg/h. CONCLUSIONS: Pulse waveform analysis exposes dose dependent effects of GTN on the aortic waveform, suggesting muscular conduit arterial dilatation with reduced wave reflection at the lowest dose, arteriolar dilatation and decreased peripheral resistance at the highest dose, and venous dilatation at the intermediate dose.

Aorta↗
PubMed2001

[Analysis on three-year follow-up results of excimer laser photorefractive keratectomy in treatment for myopia and myopic astigmatism].

OBJECTIVE: To evaluate the efficacy of excimer laser photorefractive keratectomy(PRK) on myopia and myopia astigmatism. METHODS: PRK was performed with VISXC20/20 on 377 eyes of 209 patients. Treated eyes were divided into two groups, according to their conditions before operation: Group I included 238 eyes (-1.50 to -6.00 D); Group II, 139 eyes (-6.25 to -16.00 D). All patients were followed-up for more than three years. RESULTS: Percentages of uncorrected visual acuity (UCVA) > or = 10/20 and 20/20 were 99.6% and 85.3% in Group I, and 79.9% and 48.2% in Group II respectively. Percentage of diopter < +/- 1.00 in Group I was 94.5%, and 61.9% in Group II. The rate of corneal haze of grade 0 was 100% in Group I, and 98.6% in Group II, but corneal haze of grade 2 was found in 1.2% of eyes in Group II. The postoperative intraocular pressure (IOP) of all operated eyes was normal. CONCLUSION: The results suggest that excimer laser PRK is an effective method for treating myopia and myopic astigmatism, especially for low and moderate myopia.

Adolescent↗
PubMed2001

Role of CD28/B7 costimulation and IL-12/IL-10 interaction in the radiation-induced immune changes.

BACKGROUND: The present paper aims at studying the role of B7/CD28 interaction and related cytokine production in the immunological changes after exposure to different doses of ionizing radiation. RESULTS: The stimulatory effect of low dose radiation (LDR) on the proliferative response of lymphocytes to Con A was found to require the presence of APCs. The addition of APCs obtained from both low- and high-dose-irradiated mice to splenic lymphocytes separated from low-dose-irradiated mice caused stimulation of lymphocyte proliferation. B7-1/2 expression on APCs was up-regulated after both low and high doses of radiation. There was up-regulation of CD28 expression on splenic and thymic lymphocytes after LDR and its suppression after high dose radiation (HDR), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) expression showed changes in the opposite direction. IL-12 secretion by macrophages was stimulated after both low and high doses of radiation, but IL-10 synthesis by splenocytes was suppressed by low dose radiation and up-regulated by high dose radiation. CONCLUSION: The status of CD28/CTLA-4 expression on T lymphocytes in the presence of up-regulated B7 expression on APCs determined the outcome of the immune changes in response to radiation, i.e., up-regulation of CD28 after LDR resulted in immunoenhancement, and up-regulation of CTLA-4 associated with down-regulation of CD28 after HDR led to immunosuppression. Both low and high doses of radiation up-regulated B7-1/2 expression on APCs. After LDR, the stimulated proliferative effect of increased IL-12 secretion by APCs, reinforced by the suppressed secretion of IL-10, further strengthened the intracellular signaling induced by B7-CD28 interaction.

Animals↗
PubMed2001

Effects of low dose radiation on signal transduction of neurons in mouse hypothalamus.

OBJECTIVE: Effects of low dose radiation on signal transduction of neurons in mouse hypothalamus were investigated. METHODS: In the present study competitive protein binding assay, radioimmunoassay, in situ hybridization and immunohistochemistry were used to observe the effects of whole-body irradiation with 75 mGy X-rays on the contents of cAMP and cGMP and the expressions of c-fos mRNA, Fos protein and proopiomelanocortin (POMC) mRNA in the neurons of mouse hypothalamus. RESULTS: The results showed that cAMP content in mouse hypothalamus immediately increased significantly and reached the peak value in 15 min after irradiation, and then returned to near sham-irradiation level 1 h after irradiation, followed by a small fluctuation of increase and decrease; the changes of cGMP content were basically opposite to those of cAMP content, while the changes of cAMP/cGMP ratio were basically consistent with those of cAMP content. The expression of c-fos mRNA in the neurons of hypothalamus appeared 15 min after irradiation, reached its peak value within 1 h, began to abate 2 h with its total disappearance 8 h after irradiation; the expression of Fos protein reached its peak value 8 h after irradiation, and then gradually returned to sham-irradiation level 48 h after irradiation; the expression of POMC mRNA decreased significantly 1 h after irradiation and remained at a lower level in the observation period of 12 h. CONCLUSION: These findings implicate that low dose radiation may potentiate the activity of the neurons in mouse hypothalamus, expedite their signal transduction, and down-regulate the functions of hypothalamus-pituitary-adrenocortical axis.

Animals↗
PubMed2001

G1 arrest and relative protein expressions in mouse thymocytes induced by whole body X-ray irradiation.

OBJECTIVE: To investigate the molecular regulation of G1 arrest of mouse thymocytes induced by ionizing radiation. METHODS: Cell cycle was analyzed by flow cytometry (FCM) following staining of cells with propidium iodide. Fluorescent staining and flow cytometry analysis were employed for measurement of protein expression. RESULTS: It was demonstrated that G1 phase of mouse thymocytes increased significantly at 12 h after whole body irradiation (WBI) with the doses of 0.5, 1.0 and 2.0 Gy, and at 24 h following 2.0 Gy exposure, measured by FCM. In the time course experiment, it was found that G1 phase of thymocytes increased significantly at 4 h, reached a peak level at 24 h and came down toward 48 h after WBI with 2.0 Gy X-rays. The results also showed that after 2.0 Gy exposure, the expression of proteins in mouse thymocytes increased significantly from 1 h to 8 h for p53, for p21 from 4 h to 48 h, and for MDM2 at 4 h and 8 h, measured by FCM. But no change was found for GADD45 protein expression. CONCLUSION: These results suggest that G1 arrest could be induced by a single dose of 0.5 Gy, 1.0 Gy or 2.0 Gy, and its molecular control might be established through the p53-p21 pathway.

Animals↗
PubMed2000

Low-dose whole-body irradiation (LD-WBI) changes protein expression of mouse thymocytes: effect of a LD-WBI-enhanced protein RIP10 on cell proliferation and spontaneous or radiation-induced thymocyte apoptosis.

Low-dose radiation (LDR) can potentiate cellular metabolic activities or immune functions in vivo (hormesis), and can render cells resistant to DNA or chromosome damage caused by subsequent high-dose radiation (adaptive response). Protein synthesis was required for these cellular responses to LDR. In the present study, the early expression of proteins by thymocytes in response to low-dose whole-body irradiation (LD-WBI) was investigated. The expression of novel and previously existing proteins was found in the nucleus, cytoplasm, and extracellular fluid of thymocytes at 4 hours after WBI with 75-mGy X-rays. A 10 kD protein (RIP10) was seen in the cytoplasm of thymocytes after LD-WBI was further investigated. The fraction containing RIP10 separated by Sephadex G 100 gel filtration potentiated spontaneous thymocyte, and mitogen-induced splenocyte proliferation. Western blotting demonstrated that an anti-RIP10 antibody could react with a 10-kD cytoplasm protein and also with a 13-kD nuclear protein in thymocytes at 4 h after LD-WBI. Immunocytochemical staining showed the existence of RIP10 in several immune tissues including thymus, spleen, and lymph node. RIP10 expression, as determined by immunocytochemical staining and flow cytometry, was enhanced at 4-8 h after LD-WBI. Cell-cycle arrest (G(0)/G(1) block with decreased percentage of S-phase cells), and increased levels of spontaneous or radiation-induced apoptosis were observed in thymocytes incubated with RIP10 antibody in vitro for 4 h or 24 h. These results directly demonstrated the role of RIP10 in modulating cell proliferation and apoptosis. This finding is important to understand the mechanisms underlying LDR-induced hormesis and adaptive response.

Adaptation, Physiological↗
PubMed2000

Adaptive response of thymocyte apoptosis and cell cycle progression induced by low dose X-ray irradiation in mice.

The dose-effect of adaptive response of thymocyte apoptosis and cell cycle progression induced by whole-body X-ray irradiation (WBI) was studied in male Kunming mice. The inductive doses (D1) were 25, 50, 75, 100 or 200 mGy 6 h before the challenging doses (D2) of 1.0, 1.5 or 2.0 Gy. The changes in the percentages of the thymocyte apoptotic bodies (TAB) and the cells in different phases of cell cycle were measured with flow cytometry. The percentages of TAB decreased, the arrests of G1 and G2 + M phases diminished, and the cells of DNA synthesis of S phase increased when the D1 + D2 groups was compared with the D2 groups. When D1 was 200 mGy, the adaptive response of thymocyte apoptosis and cell cycle progression were no longer induced by low dose radiation (LDR). In addition, the extracellular fluid from the splenocytes were cultured with Con A for 48 h in vitro 24 h after 75 mGy WBI was placed in the murine thymocyte suspension from mice irradiated with 2.0 Gy WBI and co-incubated. The thymocyte apoptosis decreased. Especially, noteworthy was that the percentages of TAB after the incubation for 72 h were significantly lower than those in 2.0 Gy irradiated thymocytes (P < 0.05). These results indicate that when the mice were irradiated with 25-100 mGy (D1, 12.5 mGy/min) 6 h before 1.0-2.0 Gy (D2, 0.287 Gy/min) exposure, an adaptive response of thymocyte apoptosis and cell cycle progression may be induced under the condition of WBI, and LDR (75 mGy) may change the microenvironment of immune cells and decrease the thymocyte apoptosis.

Animals↗
PubMed1999

[Electrophysiological and morphological characteristics of the visceral nociceptive neurons in cortex S II area of cats].

Electrophysiological and morphological properties of the visceral nociceptive neurons (VNNs) in the secondary somatosensory cortex (SII) area of 16 cats were investigated with intracellular recording and labeling method. Electrophysiological properties of a total of 251 neurons were identified, 109 of which were induced to discharge by stimulating the greater splanchnic nerve and therefore were simply designated as VNNs. Various patterns of the response could be recorded: excitatory (38.53%), inhibitory (42.20%) and excitato-inhibitory (19.31%). Following acquisition of electrophysiological data, neurobiotin was injected into 21 cells by electrophoresis to show their morphology and distribution in the cerebral cortex. It was found that excitatory VNNs were pyramidal neurons predominantly, whereas more inhibitory VNNs were stellate neurons.

Animals↗
PubMed1996

Thymocyte apoptosis in response to low-dose radiation.

Thymocyte apoptosis was assessed by counting apoptotic bodies with flow cytometry (FCM) and measuring DNA fragmentation with fluorescence spectrophotometry (FSP). J-shaped dose-response curves were obtained after both whole-body irradiation (WBI) of mice and in vitro irradiation of EL4 cells with doses ranging from 0.025 to 4 Gy X-rays. There was a significant reduction of apoptosis rate to below control level with doses within 0.2 Gy, and a dose-dependent increase in apoptosis with doses above 0.5 Gy. When thymocytes were cultured 24 h after WBI with 75 mGy X-rays in complete RPMI 1640 medium, a reduction in apoptosis was observed in the course of incubation for 72 h, and the presence of Con A in the medium accentuated this reduction in a dose- and time-dependent manner. The implications of these observations and the possible molecular mechanisms for future studies are proposed.

Animals↗
PubMed1995

Harmful effects of MSG on function of hypothalamus-pituitary-target gland system.

It has been demonstrated that neonatal administration of monosodium glutamate (MSG) results in a clearly defined lesion of the arcuate nucleus (AN) of the hypothalamus. The present study shows that fat was accumulated in the abdomen of male rats treated with MSG; weights of the body, pituitary and testis were lower; beta-EP content in hypothalamus decreased while L.EnK content increased; serum LH, FSH, TSH, GH and TS levels all decreased in varying degrees while serum PRL level significantly increased. The cAMP content lowered in pituitary, but nor in testes; clear histological changes occurred in testicular tissue; Se-GSH-Px activity in both testis and adrenal gland lowered while LPO level significantly increased. Both Se-GSH-Px activity and LPO level in liver increased. These results indicate that MSG is harmful to the function of the hypothalamus-pituitary-target system of neonatal rats.

Adrenal Glands↗
PubMed1994

Ionizing radiation-induced IL-1 alpha, IL-6 and GM-CSF production by human lung cancer cells.

A cell line derived from human lung cancer (AOI) was employed in the present study. A panel of cytokines were quantified by ELISA technique following cellular exposure to X-irradiation. Tremendous increase in the levels of both IL-1 alpha and IL-6 were observed, GM-CSF was also detected. A comparison of time kinetics of IL-1 alpha and IL-6 production was made with that of cell cycle progression which was determined by FCM BrdU/DNA bivariate analysis. No cell cycle specific changes were found. The biological implication of radiation-induced cytokine production was discussed.

Cell Cycle↗
PubMed1994

Effect of low dose radiation on intracellular calcium and protein kinase C in lymphocytes.

It is first reported in the present paper that whole-body irradiation (WBI) with low dose X-rays could increase intracellular calcium ions ([Ca2+]i) and stimulate protein kinase C (PKC) activity of mouse lymphocytes. Following WBI of male Kunming mice with 75 mGy X-rays at a dose rate of 12.5 mGy/min the mobilization of [Ca2+]i with Con A in CD4+ and CD8+ Cells in the thymus and spleen was potentiated and the amplitude of [Ca2+]i mobilization in thymocytes in response to anti-CD3 monoclonal antibody increased with time from 4 to 24 h following low dose radiation. The PKC activity in the homogenate of spleen was markedly stimulated 12 h after WBI with 75 mGy, reaching its peak value at 24-48 h and coming down to lower than normal on day 7. However, the PKC activity in the separated T lymphocytes reached its peak value at 12 h and that in the B lymphocytes reached its peak value on day 4, both coming down to below control on day 7. The implications of this facilitation of signal transduction in T lymphocytes in the mechanism of immunoenhancement after low dose radiation were discussed.

Animals↗
PubMed1994

Changes in lymphocyte reactivity to modulatory factors following low dose ionizing radiation.

Catecholamines (CA) and corticosterone (CS) exerted modulatory effect on the proliferative activity of splenic and thymic lymphocytes in response to mitogenic stimulation in vitro. Epinephrine (E) and norepinephrine (NE) potentiated proliferation in concentrations above 1 and 10 nmol/L, respectively, while CS showed a biphasic effect, stimulating proliferation at concentrations below 0.1 nmol/L and suppressing proliferation at concentrations above 10 nmol/L. Combination of CS with E, NE or both in an ineffective concentration of each (0.1 nmol/L) showed stimulatory effect on the proliferative response of both splenic and thymic lymphocytes to Con A. Whole-body irradiation (WBI) of mice with 75 mGy increased the reactivity of splenic and thymic lymphocytes to Con A. It is reported for the first time in the present paper that the proliferative reactivity of splenic and thymic lymphocytes from low dose irradiated mice could be further increased in the presence of suboptimal concentrations of CS and E as well as suboptimal concentrations of phorbol myristate acetate (PMA) and A23187. These findings may have significance in the mechanism of immunologic stimulation after low dose WBI.

Animals↗
PubMed1994

Signal transduction in lymphocytes after low dose radiation.

Mice were given whole-body irradiation (WBI) with 75 mGy X-rays which had previously been found to stimulate immunologic functions. This low dose radiation (LDR) potentiated [Ca2+]i mobilization in thymic and splenic lymphocytes in response to Con A and anti-CD3 McAb and activated protein kinase C in T and B lymphocytes of the spleen. The expression of TCR/CD3 molecules on the thymocytes was enhanced after LDR indicating an expedited maturation and differentiation process in the thymus. The changes in TCR/CD3 expression and [Ca2+]i mobilization in response to McAb-CD3 after LDR was found to be highly correlated. Meanwhile the transcription of c-fos and c-jun genes was up-regulated beginning 3 hours after LDR. The expression of IL2R in active thymocytes was potentiated 24 hours after LDR which coincided with the previous finding of increased secretion of IL2 by splenocytes after WBI with 75 mGy X-rays. It is first reported in the present paper that LDR could stimulate immunologic functions through facilitation of the signal transduction process in the lymphocytes.

Animals↗
PubMed1994

Experimental radiotherapy and metastasis of human lung cancer xenografts in nude mice.

Using a cell line derived from human lung cancer (AOI), we successfully established human xenografts in KSN nude mice, which showed high incidence of multiple spontaneous metastases. The highest incidence of metastasis in untreated hosts was observed in the spleen followed by the lungs and lymph nodes. The rate of metastasis reached 100% in the mice bearing large sized tumors, when metastasis to any organ or tissue was counted. Experimental radiotherapy caused remarkable redistribution of metastatic foci among different organs. Lung metastasis tended to decrease, while metastasis to the liver and the kidney was increased after radiotherapy. Radiation-induced production of cytokines was speculated to be responsible for such an alteration of metastasis pattern.

Animals↗
PubMed1993

[Protective effect of panaxatriols on function of reproductive endocrine axis in radiation-injured rats].

After whole body irradiation with X-ray 5 Gy (radiation condition: 0.31 Gy.min-1, 200 kV, 10 mA, 0.5 mm Cu and 1.0 mm Al), the male rats were given ip panaxatriols 5 mg.d-1 24 h before and after irradiation for 14 d. The results showed that hypothalamic leu-enkephalin (165 +/- 12 vs 131 +/- 14 pg.mg-1), pituitary beta-endorphin (2.3 +/- 0.5 vs 1.6 +/- 0.3 ng.mg-1) contents, and serum testosterone (1.66 +/- 0.15 vs 0.82 +/- 0.23 ng.ml-1) level were decreased, while serum FSH (1.34 +/- 0.10 vs 1.99 +/- 0.10 ng.ml-1) level increased in irradiation group vs normal control. These indices approached to control levels in irradiation + panaxatriols group. These suggest that panaxatriols have protective effects on reproductive endocrine axis and promote their recovering course from the radiation injuries.

Animals↗