Biomedical subjects

Q Yin

Publications and source records attributed to Q Yin.

At least 37 records · Page 2Linked to original sources

PubMed2000

Convergence of redox-sensitive and mitogen-activated protein kinase signaling pathways in tumor necrosis factor-alpha-mediated monocyte chemoattractant protein-1 induction in vascular smooth muscle cells.

Monocyte chemoattractant protein-1 (MCP-1) is an important component of the inflammatory response of the vessel wall and has been shown to be regulated by cytokines, such as tumor necrosis factor-alpha (TNF-alpha). However, the precise signaling pathways leading to MCP-1 induction have not been fully elucidated in vascular smooth muscle cells (VSMCs). Cytokine signal transduction involves protein kinases as well as reactive oxygen species (ROS). The relation between these 2 factors is not clear. In this study, we show that TNF-alpha induces a parallel phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (p38MAPK) and increases MCP-1 mRNA expression in cultured VSMCs. Inhibition of ERK1/2 but not p38MAPK caused a partial attenuation of MCP-1 induction (43+/-10% inhibition). Incubation of VSMCs with multiple antioxidants (diphenylene iodonium, liposomal superoxide dismutase, catalase, N-acetylcysteine, dimethylthiourea, and pyrrolidine dithiocarbamate) had no effect on TNF-alpha-mediated MCP-1 upregulation. However, simultaneous blockade of the ERK1/2 and ROS pathways by using PD098059 combined with diphenylene iodonium or N-acetylcysteine potently enhanced the ability of MAPK kinase inhibitors to abrogate MCP-1 mRNA expression (100+/-2% inhibition). Thus, parallel ROS-dependent and ERK1/2-dependent pathways converge to regulate TNF-alpha-induced MCP-1 gene expression in VSMCs. These data unmask a complex but organized integration of ROS and protein kinases that mediates cytokine-induced vascular inflammatory gene expression.

Animals↗

PubMed1999

A rat small bowel transplant model of chronic rejection: histopathologic characteristics.

BACKGROUND: The major impediment to long-term success in solid organ transplantation is the development of chronic rejection (CR). The vascular lesion of CR, transplant vascular sclerosis (TVS) is characterized by neointimal smooth muscle cell proliferation, and is driven by both immune- and nonimmune-mediated mechanisms. Although the features of chronic heart and kidney allograft rejection have been well characterized, the more immunogenic small bowel allograft has not received similar study. METHODS: F344 small bowel (SB) was transplanted heterotopically into Lewis recipients that were treated with low-dose Cyclosporine A for 15 days. Lewis recipients of F344 or Lewis SB grafts without immunosuppression, served as controls. Grafts were assessed histologically when recipients showed clinical signs of rejection or at predetermined time points. The immunological components involved in the chronic rejection process were evaluated by immunohistochemical staining. RESULTS: All SB allografts (100%) developed histologic evidence of CR Cyclosporine A. TVS was seen in 36 of the 46 (78%) of these allografts. The median time to develop TVS was 45 days. Immunohistochemical staining of chronically rejected grafts showed infiltration predominantly by CD4+ cells and macrophages, uniform up-regulation of class II MHC molecule expression, moderate to intense ICAM-1 staining in grafts harvested at postoperative day 45, and uniform neointimal cell staining for smooth muscle cell alpha-actin in the TVS lesions. CONCLUSIONS: This F344 to Lewis SB transplant model is a useful model that reproduces significant features of CR. The highly immunogenic nature of the SB allografts allows this model to serve as a stringent test for protocols designed to prevent CR.

Animals↗

PubMed1999

Reactive oxygen species mediate the activation of Akt/protein kinase B by angiotensin II in vascular smooth muscle cells.

Angiotensin II, a hypertrophic/anti-apoptotic hormone, utilizes reactive oxygen species (ROS) as growth-related signaling molecules in vascular smooth muscle cells (VSMCs). Recently, the cell survival protein kinase Akt/protein kinase B (PKB) was proposed to be involved in protein synthesis. Here we show that angiotensin II causes rapid phosphorylation of Akt/PKB (6- +/- 0.4-fold increase). Exogenous H(2)O(2) (50-200 microM) also stimulates Akt/PKB phosphorylation (maximal 8- +/- 0.2-fold increase), suggesting that Akt/PKB activation is redox-sensitive. Both angiotensin II and H(2)O(2) stimulation of Akt/PKB are abrogated by the phosphatidylinositol 3-kinase (PI3-K) inhibitors wortmannin and LY294002 (2(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one), suggesting that PI3-K is an upstream mediator of Akt/PKB activation in VSMCs. Furthermore, diphenylene iodonium, an inhibitor of flavin-containing oxidases, or overexpression of catalase to block angiotensin II-induced intracellular H(2)O(2) production significantly inhibits angiotensin II-induced Akt/PKB phosphorylation, indicating a role for ROS in agonist-induced Akt/PKB activation. In VSMCs infected with dominant-negative Akt/PKB, angiotensin II-stimulated [(3)H]leucine incorporation is attenuated. Thus, our studies indicate that Akt/PKB is part of the remarkable spectrum of angiotensin II signaling pathways and provide insight into the highly organized signaling mechanisms coordinated by ROS, which mediate the hypertrophic response to angiotensin II in VSMCs.

Angiotensin II↗

PubMed1999

Rotating Ring (Pt)-Disc (FeS2) Electrode Behavior in Hydrochloric Solutions.

A rotating ring (Pt)-disc (FeS2) electrode was used to investigate the surface oxidation process of pyrite in the hydrochloric solutions. It is reported for the first time that the oxidation intermediates of pyrite were formed on the disc electrode and then oxidized on the ring electrode. The results indicate that at a rotation rate of 20 Hz, when the disc electrode potential was in the region of 0.43 to 0.62 V and the ring electrode potential was at 1 V vs a standard calomel electrode (SCE), approximately 50% of the reacted pyrite was oxidized to ferric and sulfate ions and the other 50% was oxidized to sulfur and ferrous ions on the disc electrode. The latter was further oxidized to ferric ions on the ring electrode. As the disc electrode potential increased to 1.22 V vs SCE, more than 90% of the reacted pyrite was oxidized to ferric and sulfate ions on the disc electrode and less than 10% formed ferrous ions, which were further oxidized to ferric ions on the ring electrode. Copyright 1999 Academic Press.

Journal Article↗

PubMed1999

Twin-tube endografts for aortic aneurysms: an experimental feasibility study.

PURPOSE: To explore feasibility of twin-tube endografts (TTEGs) for treatment of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: AAAs were created in six dogs by overdilation of Palmaz stents. TTEGs made of seven 9.5-mm-diameter Gianturco Rösch Z (GRZ) stents and covered with PTFE were deployed simultaneously from both femoral arteries through 10-F sheaths to exclude the AAA. Follow-up aortography was performed immediately and at 2, 4, and 8 weeks. Two dogs were killed at 4 weeks and four were killed at 8 weeks. Gross and histologic examinations were performed. RESULTS: AAA creation and TTEG placement were successful in all six dogs. TTEGs completely excluded AAAs in five dogs. Minor temporary perigraft leak was seen in one dog immediately after stent placement. Four dogs had TTEGs patent to termination at 8 weeks. In two dogs with oversized TTEGs, one of the twin endografts occluded at 2 weeks. At autopsy, TTEGs were formed in semicircular shape and histology did not show any significant inflammatory reaction. CONCLUSION: TTEGs show promise for treatment of AAA, with the potential of reducing the introductory sheath size. Further experimental studies, particularly with TTEGs extended into iliac arteries, are warranted.

Angiography↗

PubMed1998

Schwann cells, neurotrophic factors, and peripheral nerve regeneration.

The peripheral nervous system retains a considerable capacity for regeneration. However, functional recovery rarely returns to the preinjury level no matter how accurate the nerve repair is, and the more proximal the injury the worse the recovery. Among a variety of approaches being used to enhance peripheral nerve regeneration are the manipulation of Schwann cells and the use of neurotrophic factors. Such factors include, first, nerve growth factor (NGF) and the other recently identified members of the neurotrophin family, namely, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), neurotrophin-4/5 (NT-4/5); second, the neurokines ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF); and third, the transforming growth factors (TGFs)-beta and their distant relative, glial cell line-derived neurotrophic factor (GDNF). In this review article we focus on the roles in peripheral nerve regeneration of Schwann cells and of the neurotrophin family, CNTF and GDNF, and the relationship between these. Finally, we discuss what remains to be understood about the possible clinical use of neurotrophic factors.

Animals↗

PubMed1998

Neurotrophins, neurones and peripheral nerve regeneration.

Successful peripheral nerve regeneration requires optimal conditions both in the macro-environment and micro-environment. Many methods have been used to improve the macro-environment for the regenerating nerve. However, much less is known about the micro-environment, and in particular the complex neurochemical interactions involved. Several neurotrophic factors have been shown to play an essential trophic role in the development, maintenance and regulation of neuronal function. These include nerve growth factor (NGF) and several recently identified members of the NGF family, namely brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), neurotrophin-4/5 (NT-4/5) and neurotrophin-6 (NT-6). In this review we summarize recent studies of the effects of these neurotrophins on neurones, especially their effects on motor neurones and their axonal outgrowth. We discuss prospects for the future and point out what remains to be understood about the role of neurotrophins to enhance peripheral nerve regeneration.

Animals↗

PubMed1998

Role of NADH/NADPH oxidase-derived H2O2 in angiotensin II-induced vascular hypertrophy.

Recent evidence suggests that oxidative mechanisms may be involved in vascular smooth muscle cell (VSMC) hypertrophy. We previously showed that angiotensin II (Ang II) increases superoxide production by activating an NADH/NADPH oxidase, which contributes to hypertrophy. In this study, we determined whether Ang II stimulation of this oxidase results in H2O2 production by studying the effects of Ang II on intracellular H2O2 generation, intracellular superoxide dismutase and catalase activity, and hypertrophy. Ang II (100 nmol/L) significantly increased intracellular H2O2 levels at 4 hours. Neither superoxide dismutase activity nor catalase activity was affected by Ang II; the SOD present in VSMCs is sufficient to metabolize Ang II-stimulated superoxide to H2O2, which accumulates more rapidly than it is degraded by catalase. This increase in H2O2 was inhibited by extracellular catalase, diphenylene iodonium, an inhibitor of the NADH/NADPH oxidase, and the AT1 receptor blocker losartan. In VSMCs stably transfected with antisense p22phox, a critical component of the NADH/NADPH oxidase in which oxidase activity was markedly reduced, Ang II-induced production of H2O2 was almost completely inhibited, confirming that the source of Ang II-induced H2O2 was the NADH/NADPH oxidase. Using a novel cell line that stably overexpresses catalase, we showed that this increased H2O2 is a critical step in VSMC hypertrophy, a hallmark of many vascular diseases. Inhibition of intracellular superoxide dismutase by diethylthiocarbamate (1 mmol/L) also resulted in attenuation of Ang II-induced hypertrophy (62+/-2% inhibition). These data indicate that AT1 receptor-mediated production of superoxide generated by the NADH/NADPH oxidase is followed by an increase in intracellular H2O2, suggesting a specific role for these oxygen species and scavenging systems in modifying the intracellular redox state in vascular growth.

Angiotensin II↗

PubMed1997

[Limb salvage surgery using massive allografts in malignant bone tumors].

The advantages of segmental allografts over arthoplastics are, among others, secured biological healing, easy attachment of tendons and ligaments, and desirable long-tem results. Since 1983, the authors have performed 35 resections of malignant tumors in the extremities followed by reconstructions with implantation of segmental allografts. Five types of grafts were used for the reconstruction of the skeletal defects, intercalary hemicylinder, intercalary cylinder, partial osteoarticular, total osteoarticular, and allograft-prosthetic implant composite. All the patients underwent adjunctive chemotherapy that was considered necessary. The length of follow-up ranged from 6 months to 10 years during which time 6 patients died, 25 were disease-free, and 4 survived as tumors-carriers. Complications in 28.6% of the patients included infection, graft resorption, recurrence and nonunion. Patients undergoing intercalary grafts oblained better functional results than those having osteoarticular grafts. 4 patients had biopsies and bone scans of the grafts 2-4 years postoperation with creeping substituion being observed. Segmental allograft remains a viable approach with predictable results for reconstruction of skeletal defects after resection of malignant bone tumors.

Adolescent↗

PubMed1997

[Resistant antibiotic analysis of methicillin-resistant staphylococcus].

Methicillin-resistant staphylococcus aureus is one of the important patholonic bacteria which cause nosocomial infection. In order to investigate the resistant antibiotic circumstances of this organism and hence provide foundations of prevention and treatment, we determined the resistant rates of 88 staphylococcus strains for methicillin and for other 14 kinds of commonly used antibiotics, and we determined the engendering beta-lactamase. The results showed that the isolation rate of methicillin-resistant staphylococcus aureus (MRSA) was 56%; the rate of methicillin-resistant staphylococcus coagulase-negative (MRSCoN) was 47.6%; the resistance rate and the multi-resistant rate of methicillin-resistant staphylococcus (MRS) for the 14 kinds of antibiotics were higher as compared with those of methicillin-sensitive (MSSA). Among all the tested strains, MRSA was the highest to engender beta-lactamase (92.9%); Methicillin-sensitive staphylococcus coagulase-negative (MSSCoN) was the lowest (39.4%). MRS was sensitive to vancomycin and furantoin. These suggest that when treating this bacterium, we should select these two antibiotics first.

Anti-Bacterial Agents↗

PubMed1996

Field evaluation of the QBC technique for rapid diagnosis of vivax malaria.

The QBC (quantitative buffy coat) technique was compared with that of the Giemsa-stained thick blood film (GTF) under field conditions in Junlian and Mingshan counties, Sichuan, China, for rapid diagnosis of vivax malaria. Blood samples were collected from 364 volunteer villagers, and each sample was examined with both the QBC and GTF techniques. For each GTF sample (10 microliters of blood), as many as 300 oil-immersion fields were examined; each QBC tube was inspected for up to 5 minutes. The GTF technique resulted in 86 positive blood samples and 278 negative; the QBC technique indicated 89 positive and 275 negative samples. Relative to the results obtained with GTF, the QBC technique had a sensitivity and specificity of 87.2% and 95.0%, respectively; concordance between the tests was 93.1%. The median time-to-positive diagnosis with the QBC technique (1.12 min) was 11% of that with GTF. The distribution of different developmental stages of Plasmodium vivax parasites was also examined in the centrifuged QBC tubes: all stages except schizonts could be found in the lower part of the platelet zone (the interphase between the monocyte and platelet layers), especially ring forms.

Azure Stains↗

PubMed1993

[The role of Ach in the central nerve system on pain modulation and analgesia].

This article reviews the main results in recent years of studies on the role of central Ach in pain modulation and analgesia, including: (1) cholinergically induced analgesia (CIA). Cholinomimetic drugs raised the pain threshold or inhibited the unit discharges of hypothalamus parafascicularis nuclens in rats, and these actions were revised by atropine not by nicotine. (2) Ach and acupuncture analgesia (AA). The effect of electroacupuncture was changed by administration of HC-3, atropine, etc. (3) Ach and stress analgesia (SA). Scopolamine reduced the hind foot shock induced analgesia, and this kind of SA was probably mediated by m-receptors existed at supraspinal, rather than spinal level. Swimming and immobilization analgesia were also related to Ach. These data suggested that the central cholinergic system is very important in pain modulation and analgesia and the central Ach is essential transmitter or modulator in this analgesic pathway. But the problem is whether the mechanism of CIA is involved in opiate analgesic system or not.

Acetylcholine↗

PubMed1993

[Clinical observation of the effect of pretreatment with nifedipine in preventing oxygen free radicals in the cardiopulmonary release bypass operation].

The effect of pretreatment with nifedipine in preventing oxygen free radicals release was observed in the cardiopulmonary bypass (CPB) operation. Twenty cases were divided into two groups for comparison. Nifedipine (0.6 mg/kg) was given to the test group. MDA, XO, UA and SOD were measured. These examinations were taken at pre-aortic clamping, 15 min after aortic clamping, and 30, 60, 120, 180 min after reperfusion. The results indicated that pretreatment with nifedipine reduced oxygen free radicals release in the CPB operation.

Adolescent↗

PubMed1992

[Bacterial microcolony and its primary applications].

A new rapid and useful microcolony technique was developed by using cellulose-acetate membrane as a supporter. The bacteria were inoculated on the membrane and cultivated for 3-6h. Then the membrane was rendered, fixed and colored. The microcolonies were observed and counted under the microscope. By using this technique the microcolonies of 139 strains of bacteria were observed. 72 strains of Staphylococcus were differentiated by means of observing the characteristics of the microcolonies. The correlation rate between the microcolony method and the routine method was 90.28%. This technique was also first used to determine the bacteria numbers in urine within 6h, and the advantages of it were significant compared with the plate count method.

Colony Count, Microbial↗

PubMed1992

[Electrophysiological observation on the role of the hypothalamic paraventricular nucleus in acupuncture analgesia].

In this experiment, the role of PVN in acupuncture analgesia was further investigated with electrophysiological technique. In wistar rats the unit discharge was recorded extracellularly, Noxious stimulation was applied to sciatic nerve, and the electroacupuncture was performed on acupoints "Zusanli" and "Sanyinjiao". Totally eighty-two units were recorded successfully from PVN. 49 units of them reacted to electroacupuncture with excitatory (14), inhibitory (23) or on significant effect (12). Various types of reactions including excitation (12), inhibition (6), excito-inhibition (4) or inhibito-excitation (3) were observed on 43 units during noxious stimulation of sciatic nerve. The remainder 18 units had no significant reaction. After electroacupuncture those units reacting with excitatory effect on noxious stimulation decreased their firing rate, and those with inhibitory effect increased their firing rate. The duration of nociceptive reaction was shortened after electroacupuncture in both types of units. It was suggested that electroacupuncture could influence the activities and decrease the nociceptive reactions of PVN neurons, which might be considered as electrophysiological evidence of the involvement of PVN in acupuncture analgesia.

Acupuncture Analgesia↗

PubMed1991

[Consecutive observation of the plasma MDA, XO and UA levels and erythrocyte SOD in 10 cases of cardiopulmonary bypass].

The plasma malonaldehyde (MDA), xanthine oxidase (XO) and uric acid (UA) levels and erythrocyte superoxide dismutase (SOD) were measured in 10 cases during cardiopulmonary bypass (CPB) operation. These examinations were taken at pre-aortic clamping, 15 min after aortic clamping, 30, 60, 120 and 180 min after reperfusion respectively. The results showed that MDA, XO and UA rise but SOD decreases after reperfusion. We believe that a lot of oxygen free radicals (OFR) release during peri-operative period and the XO may be an important pathway of OFR release.

Cardiopulmonary Bypass↗

PubMed1991

Environmental determinants of lung cancer in Shenyang, China.

To investigate determinants of the high rates of lung cancer in Shenyang, an industrial city in north-eastern China, a case-control study was conducted. Interviews with 1249 lung cancer patients and 1345 population-based controls revealed that cigarette smoking was the main cause of lung cancer. Smoking accounted for 55% of the lung tumours in men and 37% in women. In addition, air pollution from coal-burning heating and cooking devices was significantly linked to lung cancer, with risks rising in proportion to duration of exposure to indoor pollutants. Measurement of benzo[a]pyrene revealed average wintertime levels in air that were nearly 60 times the recommended upper limit for US cities, with even higher concentrations indoors in traditional single-storey homes using coal-burning kang (stoves). Occupational factors were also involved, the risk being elevated by three fold among smelter workers. Soil levels of arsenic and other metals rose with increasing proximity to the Shenyang copper smelter, and elevated risks of lung cancer were found among men, but not women, living within 1 km of its central stacks. Prior nonmalignant lung disease was common and was reported more often among the lung cancer patients than among controls. The findings suggest that cigarette smoking and environmental pollutants combine to account for most of the excess risk of lung cancer in this population.

Adult↗

PubMed1991

[The role of paraventricular nucleus of hypothalamus in acupuncture analgesia in rats].

Recent evidence has indicated that vasopressin (VP) can increase the pain threshold. It is not clear whether the paraventricular nucleus (PVN) of hypothalamus, which is one of the main nuclei that secrete VP in brain, is involved in the acupuncture analgesia (AA). The present study was designed to examine the role of PVN in AA. Experiments were carried out on Wistar rats using tail stimulation vocalization test to measure the pain threshold. The acupoints "Renzhong" and "Chengjiang" were selected for electroacupuncture. Electrical stimulation of PVN could increase significantly the pain threshold and enhance the effect of AA. On the contrary, electrolytical lesion of PVN could decrease the effect of AA obviously, which could be recovered by cerebroventricular injection (ICV) of 300 ng of arginine VP. Pretreatment with AVP-antiserum (ICV) could attenuate the effect of AA. These data indicated that PVN plays an important role in pain modulation and in the effect of AA. This role might be mediated by the VP-containing neurons in PVN.

Acupuncture Analgesia↗