Showing papers by "Xuzhou Medical College published in 2002"

Cardiac preconditioning with 4-h, 17°C ischemia reduces [Ca2+]i load and damage in part via KATP channel opening

Abstract: Brief ischemia before normothermic ischemia protects hearts against reperfusion injury (ischemic preconditioning, IPC), but it is unclear whether it protects against long-term moderate hypothermic ischemia. We explored in isolated guinea pig hearts1) the influence of two 2-min periods of normothermic ischemia before 4 h, 17°C hypothermic ischemia on cardiac cytosolic [Ca2+], mechanical and metabolic function, and infarct size, and 2) the potential role of KATP channels in eliciting cardioprotection. We found that IPC before 4 h moderate hypothermia improved myocardial perfusion, contractility, and relaxation during normothermic reperfusion. Protection was associated with markedly reduced diastolic [Ca2+] loading throughout both hypothermic storage and reperfusion. Global infarct size was markedly reduced from 36 ± 2 (SE)% to 15 ± 1% with IPC. Bracketing ischemic pulses with 200 μM 5-hydroxydecanoic acid or 10 μM glibenclamide increased infarct size to 28 ± 3% and 26 ± 4%, respectively. These results sugge...

M2 muscarinic receptor of spinal cord mediated increase of nNOS expression in locus coeruleus during morphine withdrawal.

Abstract: AIM: To investigate the effects of different muscarinic receptor (M) subtypes in the spinal cord on the scores of naloxone-precipitated morphine-withdrawal symptoms and the changes of nNOS expression in locus coeruleus (LC). METHODS: nNOS immunohistochemistry, intrathecal injection (it), and antisense oligonucleotides (AS-ONs) techniques were used. RESULTS: Intrathecal injection of M2-antisense oligonucleotides (M2-AS) decreased the scores of morphine withdrawal symptoms. M1-AS attenuated morphine-withdrawal symptoms, but the effect was less than that of M2-AS. The expression of nNOS positive neurons in the LC increased in morphine-dependent rats and increased to a greater extent during morphine withdrawal. Intrathecal injection of M2-AS inhibited the increase of nNOS expression in LC during morphine-withdrawal, but there was no effect in case of M1-AS. CONCLUSION: M2 muscarinic receptor of spinal cord mediated the increase of nNOS expression in LC during morphine withdrawal.

Pretreatment with midazolam suppresses morphine withdrawal response in mice and rats

Abstract: AIM: To investigate the roles of pretreatment with midazolam on morphine withdrawal in mice and rats. METHODS: Acute and chronic morphine dependence and naloxone-precipitated withdrawal models were employed in the present study. Cyclic adenosine monophosphate (AMP) content and Fos protein expression were measured by radioimmunoassay and immunocytochemistry, respectively. RESULTS: Coadministration of midazolam (2 mg/kg, ip) and morphine prevented the development of both acute and chronic morphine dependence in mice. Compared to saline-morphine group (3.0, 95 % confidence limits: 1.9-4.3 mg/kg), ED50 of naloxone-precipitated withdrawal jumping increased significantly in midazolam-morphine group (10.4, 95 % confidence limits: 8.5-12.3 mg/kg) in acute morphine-dependent mice (P<0.01). Pretreatment with midazolam lowered the number and incidence of naloxone-precipitated withdrawal jumping and prevented loss in body weight in chronic morphine-dependent mice (P<0.01). Midazolam-pretreatment inhibited the increase of Fos protein expression, not cyclic AMP content, in rat spinal cord during morphine withdrawal. CONCLUSION: Midazolam suppresses morphine withdrawal response by inhibiting hypersensitization of the spinal cord neurons, and this effect may not be mediated by cAMP pathway.

[Protective effects of paraventricular nucleus stimulation and vasopressin on gastric ischemia-reperfusion injury in rats].

Abstract: The effects of paraventricular nucleus (PVN) stimulation and vasopressin on gastric ischemia-reperfusion injury (GI-RI) were investigated in male SD rats of which the celiac artery was clamped for 30 min and reperfused for 1 h by removal of the clamp. The results were as follows. Both electrical and chemical stimulation of the PVN obviously attenuated the GI-RI. Bilateral electrolytic lesion of the nucleus tractus solitarius (NTS) or microinjection of AVP-V(1) receptor antagonist into the NTS could eliminate the protective effect of electrical stimulation of the PVN on GI-RI. Hypophysectomy did not influence the effect of electrical stimulation of the PVN. Both vagotomy and sympathectomy could increase the effect of stimulating PVN on GI-RI. Microinjection of arginine-vasopressin (AVP) into the PVN also attenuated the effect on GI-RI. These results suggest that the PVN and AVP participate in the regulation of GI-RI and play an important role in protection against GI-RI. This protective effect of PVN on GI-RI might be mediated by activation of AVP-ergic neurons in the PVN, which release AVP from the descending projection fibers and activate the AVP-V(1) receptors on the NTS neurons. The vagus and sympathetic nerves are involved in the efferent pathway exerting their effects on GI-RI. Hypophysis does not seem to be involved in the protective effect of PVN stimulation.

[The protective effects of melatonin on global cerebral ischemia-reperfusion injury in gerbils].

Abstract: AIM To investigate the effects of melatonin (MT) on histology and behavioral tests during global cerebral ischemia reperfusion in gerbils. METHODS Global cerebral ischemia was induced by occluding the bilateral common carotid arteries for 10 min in gerbils. Three doses of MT were administrated intraperitoneally 30 min prior to the onset of ischemia. Locomotor activity was measured by using the open field method 3 and 7 days after the ischemic episode. T maze test was carried out 4, 5 and 6 days after ischemia to assess the working memory of gerbils. Neuronal damage was assessed in CA1 pyramidal layer of gerbil hippocampus and evaluated 7 days after ischemia. RESULTS MT significantly reversed the locomotor activity increases, ameliorated learning and working memory deficit, and reduced the extent of CA1 hippocampal pyramidal cells injury after transient global cerebral ischemia in the Mongolian gerbil. CONCLUSION MT provides significantly protective effect against both histological and behavioral consequences of global cerebral ischemia reperfusion injury in gerbils.

Effects of ropivacaine on sodium, calcium, and potassium currents in guinea pig ventricular myocytes.

Abstract: AIM: To study the effects of ropivacaine (Rop) on sodium current (INa), L-type calcium current (ICa-L), inward rectifier potassium current (IK1), and delayed rectifier potassium current (IK) in isolated guinea pig ventricular myocytes. METHODS: Whole cell patch-clamp techniques were used in our experiment. RESULTS: At potential of -40 mV, Rop 10, 50, and 100 micromol/L decreased sodium current by 8.3 %, 33.3 %, and 62.5 %, respectively and prolonged the time constant of INa inactivation by 8.2 %, 24.7 %, and 64.4 %, respectively (n = 5 cells from 3 animals, P 0.05), respectively. CONCLUSION: Rop depressed INa and ICa-L, which may be related to its cardiotoxic effect.

[Effects of electrical stimulation of lateral hypothalamic area on gastric ischemia-reperfusion injury in rats].

Abstract: The effects of electrical and chemical stimulation and electrolytic lesion of lateral hypothalamic area (LHA) on gastric ischemia reperfusion injury (GI RI) were investigated in rats whose celiac arteries were clamped for 30 min and reperfused for 60 min by removal of the clamp The results are as follows (1) Electrical stimulation of LHA could aggravate GI RI in an intensity dependent manner by using 0 2, 0 4 or 0 6 mA current respectively Microinjection of L glutamic acid into LHA resulted in a similar effect to that of electrical stimulation of LHA on GI RI After electrolytic lesion of bilateral LHA, the area of gastric mucosal injury induced by gastric ischemia reperfusion (GI R) was smaller than that by electrical stimulation of LHA plus GI R (2) Dorsal vagal complex (DVC) lesion or vagotomy could eliminate the effect of electrical stimulation of LHA on GI RI (3) Electrical stimulation of LHA increased the content of malondialdehyde (MDA) but decreased the activity of superoxide dismutase (SOD) of ischemia reperfusion (I R) gastric mucosa (4) Electrical stimulation of LHA plus gastric I R increased gastric juice volume and total acid output, but there were no significant changes in acidity, pepsin activity and gastric barrier mucus These results indicate that the LHA is an area in the CNS exerting aggravative effects on GI RI The DVC and vagus may be involved in the regulative effects of LHA on GI RI These effects are associated with increases in gastric mucosal MDA content, gastric juice volume, and total acid output, and a decrease in SOD activityAcidity, pepsin activity and gastric barrier mucus do not seem to play an important role

Vascular endothelial growth factor gene transfer improves host endothelialization of xenogeneic biologic heart valve in vivo.

Abstract: Objective To investigate the feasibility of endothelialization of bioprosthesis by transfer of vascular endothelial growth factor (VEGF) gene. Methods Bovine pericardium treated with glutaraldehyde and L-glutamic acid waspositioned into the pig right atrium. pcD 2 /hVEGF 1 2 1 gene (1 mg) was transferred into the right ventricular myocardium using surgical sutures. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to evaluate the expression of myocardial VEGF mRNA. The determination of concentrations of VEGF protein in blood from both the right atrium and peripheral vein, and histological and ultrastructural analysis of implanted bovine pericardium were completed simultaneously. Results The concentration of VEGF derived from the right atrium in pcD 2 /hVEGF 1 2 1 group was significantly higher than that in the pcD 2 group 10 days after VEGF gene transfer (P<0.01). The expression of myocardial VEGF mRNA in pcD 2 /hVEGF 1 2 1 group was much higher in comparison with that in the pcD 2 group. The morphological analysis demonstrated that the coverage rate of host endothelium in the pcD 2 /hVEGF 1 2 1 group was 2.6 times as fast as that in the pcD2 group at 16 days after VEGF 1 2 1 gene transfer ( P< 0.01). Entire endothelialization occurred at 30 days after VEGF gene transfer. In addition, higher expression of myocardial VEGF mRNA was still available. Conclusions VEGF gene transfer by surgical suture can remarkably accelerate endothelialization of bioprosthesis, which may provide a new approach for inhibiting biological valve calcification and improve biocompatibility and long-term durability of the bioprosthesis.

Mechanism of immune escape in renal cell carcinoma

Abstract: OBJECTIVE To investigate the mechanism of immune escape in renal cell carcinoma(RCC). METHODS Fas and FasL expressions were examined by immunohistochemical technique in 44 RCC patients, with the Ki67 expression and apoptosis of tumor infiltrating lymphocytes(TIL) monitored simultaneously. Cytokines including IL2 and IFN alpha were used to induce the expression of the renal carcinoma cell lines 786-0 cells. Combination treatment of 786-0 with cytokines and Anti-Fas monoclonal antibody (FasAb) was used to induce apoptosis. FasL function was assessed by in vitro co-culture assays using renal cancer cells 786-0 and Fas-sensitive Jurkat T-cells. RESULTS (1) Fas expression rate in RCC(22.8%) was lower than that in the controlled normal kidney tissues(53.8%, P < 0.01). FasL expression rate in RCC (46.5%) was higher than that in the controlled normal kidney tissues (23.2%, P < 0.01). That of Ki67 was 32.8%, with the expressions of Fas and Ki67 showing a negative correlation (r = -0.62, P < 0.05). In contrast, the expressions of FasL and Ki67 showed a positive correlation. (r = 0.93, P < 0.01). The Fas expression of stage I was significantly higher than that of stages III and IV. The expression rate of FasL in RCC was significantly increased with RCC stage (P < 0.01). (2) The apoptotic rate of TIL in RCC (33.9%) was significantly higher than that of the normal kidney tissues (3.5%, P < 0.01). The expression of FasL and the apoptotic rate of TIL in RCC gave a positive correlation (r = 0.96, P < 0.01). (3) Fas expression rate in 786-0 cells was 13.7%. The apoptotic rate mediated by FAsAb was 9.6%. IFN alpha was able to up-regulate the Fas expression and subsequently augment the FasAb-mediated apoptosis in 786-0 cells. But IL2 did not show similar effects. (4) The FasL expression rate of 786-0 was 18.6%. FasL expressed by 786-0 cells was able to induce apoptosis of Jurkat T-cells in co-culture assays and the apoptosis of Jurkat T-cells was significantly lowered after blocking the effect of FasL with Fas-neutralizing antibody NOK-2, giving the apoptotic rates of 14.9% and 2.0%, respectively, the difference therein is statistically significant (P < 0.01). CONCLUSION Down-regulation of Fas expression and up-regulation of FasL-expression are the mechanisms through which the RCC cells escape from immune attack.

[Propofol depresses c -fos expression of NOS neurons in the spinal cord of rats with inflammatory pain].

Abstract: In formalin pain model, the effect of propofol on Fos expression in the spinal cord was examined by means of c -fos oncogene immunohistochemistry and NADPH-d histochemistry. Fos-like immunoreactive (FLI) neurons were mainly found in the ipsilateral dorsal horn after injection of formalin, some of which were FLI/NOS double-labeled neurons. Most of the FLI or FLI/NOS double-labeled neurons were observed in the medial part of lamina and the outer lamina . Before or after injection of formain, i.p. injection of propofol significantly decreased the number of FLI and FLI/NOS double-labeled neurons in all laminae (P<0.05 or P<0.01). By single i.p. injection of propofol or normal saline, few FLI neurons were found in the spinal cord. The results suggest that the antinociceptive function of propofol is possibly involved in the depression of the NOS neurons in the spinal cord.

Detection of micrometastases of lung cancer by using lunx mRNA specific reverse transcription-polymerase chain reaction

Abstract: Objective: To detect of lung cancer micrometastases in peripheral blood and regional lymphatic nodes by using lunx mRNA specific reverse transcription-polymerase chain reaction (RT-PCR). Methods: RT-PCR was used to detect lunx mRNA in peripheral blood of 26 patients with lung cancer. We also detected 44 regional lymphatic nodes obtained from 25 patients with lung cancer who underwent curative lobectomy. All the 44 regional lymphatic nodes were also examined by histopathology. Micrometastatic tumor cells in the peripheral blood and regional lymphatic nodes were semiquantitatively determined with the ratio of lunx band intensity to the glyceraldehydes-3-phosphate dehydrogenase band intensity. Results: The positive detection rate of lunx mRNA in peripheral blood for non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) patients were 60% (12/20) and 67% (4/6) respectively. 16 (36.4%) of regional lymphatic nodes from 44 lung cancer patients were positive by RT-PCR while 6 (13.6%) were positive by histopathology (x2=6.06, P=0.014). However, no blood samples and lymphatic nodes from patients with benign pulmonary diseases or normal volunteers were positive for lunx mRNA. The positive detection rate of lunx mRNA in bone marrow of NSCLC amd SCLC patients were 65% (13/20) and 67% (4/6) respectively. Conclusion: RT-PCR amplification of lunx mRNA is an sensitive and specific means to detect early haematogenous and regional lymphatic nodes dissemination of cancer cells for patients with lung cancer.

[Site-directed mutagenesis of the cysteines of human IL-18 and its effect on IL-18 activity].

Abstract: To study the structure-function relationships of human IL-18(hIL-18), site-directed mutagenesis was used to generate four hIL-18 cysteine mutants, C 74S, C 104S, C 112S and C 163S. The cDNAs of the four cysteine mutants were inserted into prokaryotic expression vector pJW2 and expressed as inclusion bodies in E.coli. The inclusion bodies were washed with 2 mol/L urea, dissolved in 8 mol/L urea, and purified by chromatography on Sephadex G-100 column. The purity of the purified mutants were greater than 90% as judged by SDS-PAGE. The activity of rhIL-18 C 74S, C 104S, C 112S and C 163S accounted for 5%, 81%, 58% and 11% of wild type, respectively. These results suggest that Cys 74 and Cys 163 play important roles in inducing IFN-γ production in human peripheral blood mononuclear cells.