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Biomedical subjects

Y M Guo

Publications and source records attributed to Y M Guo.

13 recordsLinked to original sources
PubMed2006

Dietary conjugated linoleic acid enhances spleen PPAR-gamma mRNA expression in broiler chicks.

1. The anti-inflammatory effects of dietary conjugated linoleic acid (CLA) on broilers repeatedly challenged with lipopolysaccharide (LPS) were investigated. 2. Day-old broiler chicks were allotted into three treatment groups and fed on a control diet or diets containing 5.0 or 10.0 g CLA/kg diet. Six chicks from each treatment were injected with LPS (0.25 mg/kg body weight) at 16, 18 and 20 d of age. Splenic cyclooxygenase (COX) and inducible nitric oxide synthase (iNOS) activities, and prostaglandin E(2) (PGE(2)) and nitric oxide (NO) production as well as peroxisome proliferator-activated receptor-gamma (PPAR-gamma) mRNA expression were measured at 21 d of age. 3. Chicks fed 10.0 g CLA/kg diet had lower COX activities and PGE(2) production that the controls. Dietary CLA (10.0 g/kg) did not significantly diminish LPS-induced enhancement of COS-2 activity, inhibited the subsequent increase in PGE(2) production. 4. Regulation of COX-1 activity contributed to the difference in PGE(2) production. 5. CLA did not markedly attenuate the increase of iNOS activity and NO production caused by LPS challenge. Chicks fed CLA had lower iNOS activity and NO production than the controls. 6. Dietary CLA activated splenic PPAR-gamma mRNA expression and increased PPAR-gamma mRNA expression after LPS injection. 7. These results suggest that dietary CLA has immunomodulatory effects in the spleen by restricting basal PGE(2) and NO to lower levels and enhancing PPAR-gamma mRNA expression. During the inflammatory response, dietary CLA did not alleviate the increase in COX-2 and iNOS activities but enhanced PPAT-gamma mRNA expression.

Animal Feed↗
PubMed2005

Effects of dietary coenzyme Q10 supplementation on hepatic mitochondrial function and the activities of respiratory chain-related enzymes in ascitic broiler chickens.

1. One hundred and sixty 1-d-old Arbor Acre male broiler chicks were fed with maize-soybean based diets for 6 weeks in a 2 x 2 factorial experiment. The factors were CoQ10 supplementation (0 or 40 mg/kg) and Escherichia coli lipopolysaccharide (LPS) challenge (LPS or saline). 2. CoQ10 was supplemented from d 1. From d 18, the chickens received three weekly i.p. injections of LPS (1.0 mg/kg BW) or an equivalent amount of sterile saline as control. From d 10 on, all chickens were exposed to low ambient temperature (12 to 15 degrees C) to induce ascites. 3. The blood packed cell volume and ascites heart index of broiler chickens were reduced by dietary CoQ10 supplementation. Mitochondrial State 3 and State 4 respiration, respiratory control ratio and phosphate oxygen ratio were not changed, but H+/site stoichiometry of complex II + III was elevated by dietary CoQ10 supplementation. 4. Cytochrome c oxidase and H+-ATPase activity were increased by CoQ10 supplementation, whereas NADH cytochrome c reductase and succinate cytochrome c reductase were not influenced. Mitochondrial anti-ROS capability was increased and malondialdehyde content was decreased by CoQ10 supplementation. 5. The work suggested that dietary CoQ10 supplementation could reduce broiler chickens' susceptibility to ascites, which might be the result of improving hepatic mitochondrial function, some respiratory chain-related enzymes activities and mitochondrial antioxidative capability.

Animal Feed↗
PubMed2004

Reduction of ascites mortality in broilers by coenzyme Q10.

Effects of coenzyme Q10 (CoQ10) supplementation on growth performance and ascites were studied in broilers. One hundred eighty 1-d-old Arbor Acre male broiler chicks were randomly allocated into 3 groups with 6 replicates each. From d 8, the diets were supplemented with CoQ10 at levels of 0, 20, and 40 mg/kg, respectively. From d 15 to 21, all the chicks were exposed to low ambient temperature (15 to 18 degrees C) to induce ascites. Average feed intake, BW gain, and feed conversion ratio of the broilers during 0 to 3 wk, 3 to 6 wk, and 0 to 6 wk were measured. The results showed that there were no influences observed on broilers' growth performance, but the mortality due to ascites was reduced by CoQ10 supplementation (P < or = 0.05). Erythrocyte osmotic fragility (EOF) was significantly decreased by 40 mg/kg CoQ10 compared with the control, but no significant changes were observed on blood packed cell volume (PCV) among the treatments. Pulmonary arterial diastolic pressure was significantly decreased on d 36, but no significant changes were observed on right ventricular pressure (RVP), pulmonary arterial systolic pressure, and the maximum change ratio of right intraventricular pressure (+/- dp/ dtmax). Ascites heart index (AHI) was significantly decreased by 40 mg/kg CoQ10 supplementation (P < or = 0.05). The results of this study suggested that CoQ10 has a beneficial effect in reducing ascites mortality in broilers, and 40 mg/kg CoQ10 seems to be more effective than 20 mg/ kg CoQ10.

Animal Feed↗
PubMed2001

Bis[mu-2-[(1,5-diaza-1-cyclooctyl)-methyl]phenolato-N,N',O:O]bis-[chlorozinc(II)]diacetone solvate: design of a square-pyramidal ZnN2O2Cl complex.

The title complex, [Zn(2)(C(13)H(19)N(2)O)(2)Cl(2)].2C(3)H(6)O, resides on a crystallographic inversion center. The two Zn(II) centers bridged by the phenoxo groups are in pentacoordinated distorted square-pyramidal coordination environments with an intramolecular Zn...Zn distance of 3.175 (3) A. The mesocyclic ligand takes a boat-chair conformation and an H atom from the 1,5-diazacyclooctane ring effectively blocks the axial coordination site opposite the Cl ligand to form the ZnN(2)O(2)Cl geometry. The crystal structure is stabilized by a N-H...O hydrogen bond between the amino group and an acetone molecule.

Crystallography, X-Ray↗
PubMed2001

Report of the consensus conference on diagnostic criteria of ALI/ARDS at high altitudes in Western China.

China is a mountainous country. The Qing-Zang plateau, Yun-Gui plateau, and Yellow Land plateau, which are known as the world's ridge, are located in the west of China. The highland area over 3,000 m in height occupies one-sixth of the land area of China and half the highland area of the world. About 60-80 million people live in the regions where the elevation ranges from 1,500 m to 4,000 m. In the latter half of the last century, the influence of complex environmental factors on the human body, such as low oxygen pressure, cold climate, strong radiation, high wind speed, and super-evaporation, were studied in an extensive and profound way and formed an important field of altitude medicine. For a long time, many researchers have carried out investigations related to the systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS), and multiple organ dysfunction syndrome (MODS) and its pathophysiological mechanism initiated by cytokines and mediators, regarding which many problems are still unclear. However, systematic research into the mechanism from SIRS to ARDS to MODS in the highlands remains blank. The diagnostic criteria of ALI/ARDS in the highlands are quite different from that in the plain, and thus was a central topic for discussion at this meeting.

Adaptation, Physiological↗
PubMed2000

Bis(1,5-diazacyclooctane-N,N')nickel(II) dibromide.

The crystal structure of the title complex, [Ni(C(6)H(14)N(2))(2)]Br(2), consists of discrete [Ni(C(6)H(14)N(2))(2)](2+) cations and bromide counter-anions. The Ni(II) ion is at the center of symmetry and is four-coordinated by four nitrogen donors of the mesocyclic ligand 1,5-diazacyclooctane (DACO) [Ni-N 1.935 (2)-1.937 (2) A]. The coordination geometry of Ni(II) can be considered as square planar and both DACO ligands take the boat-chair conformation. The bromide anions are hydrogen bonded with the nitrogen donors of the ligands to form a macrocycle-like ring system.

Journal Article↗
PubMed2000

Effect of TCDD on maternal toxicity and chorionic gonadotropin--bioactivity in the immediate post-implantation period of macaque.

The purpose of this experiment was to observe the alterations in bioactivity of chorionic gonadotropin (CG) associated with early fetal loss (EFL), induced by the environmental toxin TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) in the cynomolgus macaque. Ten of twelve females administered single doses of 1, 2 or 4 microg/kg TCDD on gestational day (GD) 12 had EFL from ten to twenty days later. Seven control animals treated only with the vehicle had normal pregnancies. Blood samples were repeatedly collected for hormone evaluation, from two days before treatment to thirty-one days following treatment. Immunoreactive monkey chorionic gonadotropin (mCG) was measured in serum using ELISA, and bioactive mCG was measured using a luminescence LH/CG bioassay. No change in immunoreactive mCG levels was detected as a result of TCDD, treatment, but bioactive mCG levels were significantly lower in TCDD-treated animals compared to controls. This change in bioactivity of mCG was also reflected in the ratio of mCG bioactivity to mCG immunoreactivity (B/I ratio) which began to rise in normal pregnancies by GD 20, but did not rise in TCDD treated animals. These results demonstrate that normal pregnancy in the monkey, as in humans, is characterized by a post-implantation change in the B/I ratio of CG. These findings therefore suggest that changes in the production of bioactive CG may be used as a biomarker of environmental toxicant exposures which lead to EFL.

Animals↗
PubMed2000

[Nitric oxide changes aortic function in rats with renal hypertension].

This work was undertaken to investigate the effect of nitric oxide (NO) on aortic function of two-kidney and one-clip (2K1C) rats with renal hypertension. Animals were divided into 5 groups: the sham operation, 2K1C, captopril, L-arginine and L-NAME groups. The results are as follows. At the 4th week after constriction of the left renal artery, the mean arterial pressure was significantly elevated. In isolated aortic rings, acetylcholine-induced dilation was attenuated, and phenylephrine induced contractile response was markedly enhanced. The level of aorta cGMP content was significantly lowered. These changes were abolished in 2K1C rats treated with captopril. L-arginine partially reversed the aortic vascular reactivity of 2K1C rats, and elevated aortic cGMP content. In 2K1C rats treated with nitric oxide synthase inhibitor, L-NAME, blood pressure was increased further, acetylcholine-induced aorta diastolic response was attenuated further and cGMP content reduced, while phenylephrine-induced contractile response was unaffected. These results suggest that deficiency of nitric oxide production and increase in renin-angiotensin system activity may contribute to vascular endothelial dysfunction of 2K1C rats, and these factors may be involved in development and maintenance of 2K1C renal hypertension.

Animals↗
PubMed1990

[Effects of serotonin on the electric activity of paraventricular neurons of in vitro rat hypothalamic slices].

Hypothalamic slices were prepared with a vibratome. The spontaneous discharge of 46 paraventricular neurons was recorded by glass microelectrode from 20 such slices, and effects of serotonin on spontaneous discharge were observed. After perfusing the brain slices with artificial cerebro-spinal fluid containing serotonin (10(-6) mol/L) for 3 min, discharge rate of 16 units is significantly increased with latency 1.21 +/- 1.21 (mean + SD) min, this response is blocked by serotonin antagonist, cyproheptadine. The discharges of 3 units were decreased, but 25 units non-responsive. The experimental results suggest that about 1/3 of paraventricular neurons can be activated by topical application of serotonin via the activation of 5-HT receptors.

Animals↗
PubMed1990

[Traumatic respiratory distress syndrome on plateau: diagnosis and treatment].

Twenty-seven adult patients, living at plateau, developed acute respiratory syndrome after severe trauma or major operation, were reported. Seven of them died. The clinical pictures were also of severe air-hunger, cyanosis and hypoxemia associated with diffusive interstitial edema of lungs, while the mean values of blood gases were much less compared with those of patients on plain, being P-a O2 33 mm Hg, Sat. O2 71%, PaCO2 31 mmHg, A-aDO2 426 mm Hg. The diagnostic points of ARDS of patient on plateau have been suggested and the urgent requirement of management for these patients on plateau has been emphasized and described.

Adolescent↗
PubMed1990

[Effects of noradrenaline and acetylcholine on electric activity of paraventricular neurons of rat hypothalamic slices].

The effects of noradrenaline (NA) and acetylcholine (ACh) on 90 paraventricular neurons from 31 hypothalamic slices prepared from rat were observed. After perfusing the brain slices with NA (10(-6) mol/L, 3 min), discharge rate of 14/73 (17%) nonphasic and 7/12 (58.3%) phasic neurons was significantly increased, while that of 10/73 (12%) nonphasic and 2/12 (16.6%) phasic neurons was significantly decreased, even ceased. 50/73 (64%) of the nonphasic and 3/12 (25%) of the phasic neurons were non-responsive. The effects of NA on the nonphasic neurons were completely blocked by alpha receptor blocker phentolamine. The effects of NA on phasic neurons were partly blocked by phentolamine or propranolol (beta receptor blocker). After perfusing hypothalamic slices with ACh (10(-7) mol/L, 3 min), the firing rate of 15/73 (19%) nonphasic and 6/12 (50%) phasic neurons was increased, while that of 9/73 (11%) nonphasic and 2/12 (16.6%) phasic neurons was decreased. 54/73 (69%) nonphasic and 4/12 (33.3%) phasic neurons were non-responsive. The effect of ACh on the neurons could be reversed by atropine. The effect of scopolamine (M blocker) is similar to that of atropine. The experimental results suggest that the excitatory or inhibitory effect of NA or ACh on paraventricular neurons has mediated respectively by alpha, beta or M receptors.

Acetylcholine↗