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Biomedical subjects

C Song

Publications and source records attributed to C Song.

At least 91 records · Page 5Linked to original sources
PubMed1998

An assessment of the effects of central interleukin-1beta, -2, -6, and tumor necrosis factor-alpha administration on some behavioural, neurochemical, endocrine and immune parameters in the rat.

Despite a vast amount of research into the actions of cytokines within the central nervous system, the pharmacological role and/or physiological function of the various cytokines within the central nervous system is still not fully understood. The present study evaluated the effects of intracerebroventricular administration of interleukin-1beta, -2, -6 (20 ng) and tumour necrosis factor-alpha (40 ng) on elevated plus maze behaviour, monoamine levels in the hypothalamus, hippocampus and amygdala, plasma corticosterone and catecholamine concentrations and Concanavalin A-induced splenic lymphocyte proliferation in the rat. Both interleukin-1beta and tumour necrosis factor-alpha induced "anxiogenic-like" effects on the elevated plus maze, whereas interleukin-2 and interleukin-6 did not. However only interleukin-1beta led to endocrine variations often associated with stress and anxiety. Cytokine specific alterations in monoamine levels were evident in the hypothalamus and hippocampus, while neurotransmitter concentrations in the amygdala were not significantly altered by cytokine treatment. In addition, interleukin-1beta reduced Concanavalin A-induced lymphocyte proliferation, whereas the other cytokine treatments failed to significantly alter this response. These results demonstrate that in some, but not all, respects interleukin-1beta administration produced "stress like" effects on behaviour, monoamine neurotransmitters, hypothalamic pituitary adrenal axis activity and immune function, while the other cytokines produced less consistent effects on these parameters. It is noteworthy that although interleukin-1beta and tumour necrosis factor-alpha provoked an anxiogenic response in the elevated plus maze test of anxiety, neither cytokine significantly altered amygdaloid noradrenergic or serotonergic activity, as many previous studies have implicated increased amygdaloid noradrenergic and/or serotonergic activity in the pathophysiology of anxiety.

Animals↗
PubMed1998

The influence of psychological stress on total serum protein and patterns obtained in serum protein electrophoresis.

BACKGROUND: Significant alterations in total serum protein (TSP) patterns obtained in serum protein electrophoresis and serum proteins have been reported in patients with major depression and in subjects submitted to a combination of psychological and physical stress. The aim of the present study was to examine the effects of academic examination stress, on TSP and patterns obtained in serum protein electrophoresis. METHODS: TSP and the concentrations and percentages of the major electrophoretically separated serum proteins were measured in 41 healthy biomedical students the day before a difficult academic examination (i.e. the stressful condition), as well as a few weeks before and after the stressful condition (i.e. two baseline conditions). RESULTS: Academic examination stress increased TSP and the alpha 1, alpha 2, beta and gamma concentrations in stress-reactors, but not in stress non-reactors (as defined by changes in the Perceived Stress Scale). Academic examination stress reduced the percentage of albumin in the stress-reactors, but not in stress non-reactors. There were significant positive relationships between the stress-induced changes in TSP and serum alpha 2, beta and gamma concentrations and the stress-induced changes in the Perceived Stress Scale. CONCLUSIONS: The results show that even mild psychological stress of short duration can lead to measurable changes in TSP and in patterns obtained in serum protein electrophoresis.

Acute-Phase Proteins↗
PubMed1998

Arterial uptake of biodegradable nanoparticles: effect of surface modifications.

Restenosis is the reobstruction of an artery following interventional procedures such as balloon angioplasty or stenting. Local pharmacotherapeutic approaches using controlled release systems are under investigation to inhibit the regional pathophysiologic process of restenosis. We have been investigating biodegradable nanoparticles (100 +/- 39 nm in diameter, mean +/- sd) for the local intra-arterial drug delivery. The purpose of this study was to investigate nanoparticle surface modifications (see Table 1) to enhance their arterial uptake. The PLGA (polylactic polyglycolic acid copolymer) nanoparticles were formulated by an oil-in-water emulsion solvent evaporation technique using a 2-aminochromone (U-86983, Upjohn and Pharmacia) (U-86) as a model antiproliferative agent. The various formulations of nanoparticles were evaluated for the arterial wall uptake by using an ex-vivo dog femoral artery model. The selected formulations were then tested in vivo in acute dog femoral artery and pig coronary artery models. The nanoparticles surface modified with a cationic compound, didodecyldimethylammonium bromide (DMAB), demonstrated 7-10-fold greater arterial U-86 levels compared to the unmodified nanoparticles in different ex-vivo and in-vivo studies. The mean U-86 levels were 10.7 +/- 1.7 microg/10 mg (dog) and 6.6 +/- 0.6 microg/10 mg (pig) in the artery segments ( approximately 2 cm) which were infused with the nanoparticles. The pig coronary studies further demonstrated that the infusion of nanoparticles with higher U-86 loading reduced the arterial U-86 levels, whereas increasing the nanoparticle concentration in the infusion solutions increased the arterial U-86 levels. The biodistribution studies in pigs following coronary arterial administration of nanoparticles demonstrated disposition of U-86 in the myocardium and distally in the liver and the lung. The mechanism of enhanced arterial uptake of the DMAB surface modified nanoparticles seems to be due to the alteration in the nanoparticle surface charge. The unmodified nanoparticles had a zeta potential of -27.8 +/- 0.5 mV (mean +/- sem, n = 5), whereas the DMAB modified nanoparticles demonstrated a zeta potential of +22.1 +/- 3.2 mV (mean +/- sem, n = 5). The adsorption of DMAB to the nanoparticle surface followed the Freundlich isotherm with binding capacity k = 28.1 microg/mg and affinity constant p = 2. 33. In conclusion, surface modified nanoparticles have potential applications for intra-arterial drug delivery to localize therapeutic agents in the arterial wall to inhibit restenosis.

Animals↗
PubMed1998

Characterization of CB1 cannabinoid receptors using receptor peptide fragments and site-directed antibodies.

The mechanism by which CB1 cannabinoid receptors are coupled to the Gi/Go class of G proteins was studied. A peptide representing the juxtamembrane carboxyl terminus robustly stimulated guanosine-5'-O-(3-thio)triphosphate binding. Peptides simulating subdomains of the third intracellular loop (IL3) activated minimally when present alone but produced additive effects when present in combination. Peptides representing the amino-side IL3 and the juxtamembrane carboxyl terminus autonomously inhibited adenylate cyclase, and this response was not significantly augmented or inhibited by peptides representing other intracellular domains. Site-directed antipeptide antibodies developed against the domains of the amino terminus, first extracellular loop, amino-side IL3, and juxtamembrane carboxyl terminus of CB1 receptors failed to influence binding of [3H]CP-55940. However, IgG raised against the amino-side IL3 diminished the agonist-dependent inhibition of adenylate cyclase. These experiments suggest that the juxtamembrane carboxyl terminus is critical for G protein activation by CB1 cannabinoid receptors and that the amino-side IL3 also may interact with Gi proteins leading to inhibition of adenylate cyclase.

Adenylyl Cyclase Inhibitors↗
PubMed1998

Studies on chemical constituents and immunological function activity of hairy root of Astragalus membranaceus.

Using a large-scale culture technique, the hairy roots of Astragalus membranaceus were produced with a yield reaching 10 g/L. The results from RP-HPLC detection showed that the contents of crude saponin and astragaloside i.v. in the hairy roots were 5.81% and 0.14%, respectively. Six isoflavonoid compounds were also determined. Polysaccharide analysis showed that the total polysaccharide content in the hairy roots was 22.97%; of this content, acidic 8.29% and soluble 14.88%. In comparison with the dry roots, the hairy roots contained higher crude saponin and soluble polysaccharide contents, similar astragaloside i.v. content and lower contents of 6 isoflavonoids, total and acidic polysaccharides, showing that the quality of both types of roots was similar. Regaining the immunity function of rats with low immunity after feeding the aqueous extract of the hairy roots produced by large-scale culture showed that its capacity was similar to the dry roots of A. membranaceus in increasing the immunity function. The results in this paper give evidence that the hairy roots may be a new source of A. membranaceus.

Animals↗
PubMed1998

[Glucose-6-phosphate dehydrogenase mutations among Cantonese revealed by polymerase chain reaction using dried blood spots].

OBJECTIVE: To analyze G6PD gene mutation in 168 Cantonese G6PD deficient male infants. METHODS: PCR products were amplified directly from dried blood spots on filter paper using 7 pairs of special primers followed by digestion with a restriction enzyme. RESULTS: Of the 168 samples, 72(42.8%) were G6PD 1376 G-->T mutation, 35 (20.8%) were G6PD 1388 G-->A, 30(17.9%) were G6PD 95 AG, 6(3.6%) were G6PD 392 G-->T, and 3(1.8%) were G6PD 1024 C-->T. No G6PD 493 A-->G and 487 G-->A mutation were found, and 22(13.1%) were not defined. CONCLUSION: 1. The three G6PD mutations at 1376, 1388 and 95 were common in Cantonese. 2. Dried blood spots collected on filter paper provide an easy way of sample collection, storage and transport for the epidemiological study of inherited disease.

Adult↗
PubMed1998

[Deletion polymorphism in the angiotensin converting enzyme gene associated with essential hypertension in Hans Chinese population].

OBJECTIVE: To investigate whether the polymorphism of the angiotensin-converting enzyme(ACE) gene is associated with essential hypertension in Chinese. METHODS: A case-control study was carried out using 134 hypertensive (HT) and 165 normotensive (NT) subjects. The insertion/deletion (I/D) polymorphism of ACE gene was detected by polymerase chain reaction (PCR). RESULTS: The difference of genotype and derived allele frequencies for deletion of ACE gene between hypertensive and normotensive subjects were statistically significant(i.e. 51.9% vs 15.7 and 0.69 vs 0.31 for hypertensive and normotensive respectively, P < 0.05). CONCLUSIONS: The possession of D/D homozygote genotype of the ACE gene might be a marker for genetic susceptibility to Hans hypertension in Chinese.

Adult↗
PubMed1998

[Determination of 6 isoflavonoids in the hairy root cultures of Astragalus membranaceus by HPLC].

An accurate RP-HPLC method for the determination of 10-hydroxy-3, 9-dimethoxypeterocarpan, (3R) 8,2'-dihydroxy-7,4'-dimethoxyisoflavan, formonenetin (7-hydroxy-4'-methoxyisoflavone), 8, 3'-dihydroxy-7, 4'-dimethoxy-isoflavone, 2'-hydroxy-3', 4'-dimethoxyisoflavan-7-O-glucopyranoside and alycosin (7,3'-dihydroxy-4'-methoxyisoflavone) in the hairy root cultures of Astragalus membranaceus was developed. Among them, 10-hydroxy-3, 9-dimethoxypeterocarpan, (3R) 8,2'-dihydroxy-7,4'-dimethoxyisoflavan and 8,3'-dihydroxy-7,4'-dimethoxyisoflavone were new compounds in Astragalus membranaceus. The analytical column was Nucleosil C18. The mobile phases were methanol-water = 3:2 and 1:1 (v/v). The detection wavelengths were 254 nm and 280 nm. Calibration graphs were rectilinear between 2.5 micrograms and 12.5 micrograms. The recoveries were between 96.47% and 103.33%. The relative standard deviations (RSDs) of measurement precision test were 2.57%-6.52%. The flavonoid contents in the hairy root cultures were between 0.0005% and 0.0065% (dry weight).

Astragalus propinquus↗
PubMed1998

[Increase in pulmonary vascular permeability caused by increased adhesiveness of polymorphonuclear leukocytes and superoxide].

We report that mechanical stimulation of human neutrophils results in their accumulation in isolated rat lungs and in an increase in pulmonary vascular permeability. To determine whether reactive oxygen species were involved in this increase and, if so, whether it is mediate by xanthine oxidase metabolites, we assessed the effect of stimulated and unstimulated neutrophils, and of a superoxide scavenger, superoxide dismutase (SOD), and a xanthine oxidase inhibitor, allopurinol (ALLO) on pulmonary vascular permeability in isolated perfused lungs from Sprague-Dawley rats. Pulmonary vascular permeability in isolated rat lungs was assessed using a filtration coefficient determined by gravimetry. To quantify neutrophil accumulation in the lung, we measured myeloperoxydase (MPO). Neutrophils were stimulated by gentle agitation in a glass container for 10 s and Mac-1 was subsequently upregulated on the surface of the neutrophils. In lungs that received stimulated neutrophils, the pulmonary vascular filtration coefficient was about 5 times higher than in lungs that received unstimulated neutrophils. An increase in filtration coefficient was almost completely blocked by pretreatment with SOD or ALLO. However, the accumulation of stimulated neutrophils was not, or only partly, blocked by SOD or ALLO, respectively. We conclude that the increase in pulmonary vascular permeability caused by mechanically stimulated neutrophils was partly mediated by reactive oxygen species generated via the xanthine oxidase system.

Animals↗
PubMed1997

Influence of psychogenic and neurogenic stressors on endocrine and immune activity: differential effects in fast and slow seizing rat strains.

Variations of plasma ACTH and corticosterone, as well as splenic macrophage activity and mitogen-induced cell proliferation, were determined in rats following 15 min of either the neurogenic stressor of restraint or by a purely psychogenic stressor consisting of exposure to a ferret. The effects of these stressors were assessed in two strains of rats that were selectively bred for either Fast or Slow kindling epileptogenesis triggered in response to amygdala stimulation. The stressors differentially influenced behavioral responses, endocrine activity, and immune functioning, and these effects varied with the strain of rat. In response to restraint the Fast rats exhibited protracted struggling, while the Slow rats tended to be immobile. In contrast, upon ferret exposure the Fast rats showed greater immobility than the Slow rats. The stressors also induced marked elevations of plasma ACTH and corticosterone. Whereas the ACTH and corticosterone increases were more pronounced in response to the ferret in the Slow rats, restraint resulted in a markedly greater rise of plasma ACTH in the Fast strain. Proliferation of splenic lymphocytes in response to Con A and LPS were elevated in Fast seizing rats, while macrophage activity, as determined by oxygen burst following addition of PMA and luminol to splenic mononuclear cells, was greater in the Slow seizing strain. While neither stressor influenced cell proliferation in either the Fast or Slow rats, macrophage activity was greatly suppressed by ferret exposure only in the Slow rats. Taken together, it appears that while stressors influence behavior and immune and endocrine functioning, these effects may vary as a function of the interaction of the strain of rat and the specific type of stressor employed.

Adrenocorticotropic Hormone↗
PubMed1997

Effect of chronic treatment with piracetam and tacrine on some changes caused by thymectomy in the rat brain.

Thymectomized rats, 5 weeks after surgery, showed a significant impairment in learning and memory as shown by deficits in passive avoidance and in the Morris water maze test. The behaviour of the thymectomized rats in the "open field" apparatus was largely unchanged. Following treatment for 20 days with either piracetam (500 mg/kg) or tacrine (3.0 mg/kg), the deficit in passive avoidance learning was largely reversed. Chronic treatment with tacrine also reversed the deficit in the behaviour of the thymectomized rats in the Morris water maze. The effects of thymectomy on the biogenic amines and some of their metabolites in the amygdaloid cortex, hypothalamus, striatum and olfactory bulbs were also determined. Relative to the sham-operated controls, thymectomy resulted in a reduction in the noradrenaline concentration in the amygdala, hypothalamus, and olfactory bulbs. This effect was reversed by chronic piracetam and tacrine treatments. The concentration of dopamine was also reduced in the olfactory bulbs after thymectomy whereas in the striatum the concentration of 5-hydroxytryptamine (5-HT; serotonin) was increased. The concentration of gamma amino butyric acid (GABA) was determined in amygdaloid cortex and hippocampus only. The only significant change occurred following chronic treatment of thymectomized rats with tacrine, when a significant elevation of GABA was found. Neither piracetam nor tacrine produced any change in the amines of their metabolites in the sham-operated controls. Tacrine, however, elevated the dopamine and reduced the 5-HT content of the hypothalamus and increased the 3,4-dihydroxylphenylacetic acid concentration of the striatum of thymectomized rats. Examination of the differential white blood cell count of the thymectomized rats showed that the percentage of lymphocytes was decreased, and the percentage of neutrophils increased, relative to the sham-operated controls. Chronic lacrine, but not piracetam, treatment reversed the lesion-induced changes.

Animals↗
PubMed1997

Effect of chronic pretreatment with the sigma ligand JO 1784 on CRF-induced changes in behaviour, neurotransmitter and immunological function in the rat.

The effects of the chronic administration of the sigma ligand JO 1784 (igmesine) CRF-induced changes in some behavioural, immune, endocrine and neurotransmitter parameters were studied. In the elevated plus maze, CRF (1.0 microgram i.c.v. daily x 5 days) induced a reduction in the number of entries and time spent on the open arms was significantly attenuated by the sigma ligand JO 1784 (3 mg/kg x 21 days) treatment. In the open field apparatus, the CRF-induced increase in the locomotor activity was also reduced by JO 1784 administration. JO 1784 treatment did not alter the concentration of the biogenic amine transmitters in the hypothalamus, nor reverse the increase in the turnover of serotonin and dopamine caused by CRF. JO 1784 treatment also failed to reverse a CRF-induced increase in the serum corticosterone, but it did reverse the reduction in phytohaemagglutinin and concanavalin A-induced lymphocyte proliferation caused by CRF but not the changes in the lymphocyte and neutrophil numbers caused by the peptide. These results demonstrate that JO 1784 has some antistress properties in CRF-treated rats.

Animals↗
PubMed1997

[The role of periaqueductal gray neurotensin in electroacupuncture analgesia].

The effect of periaqueductal gray (PAG) injection of neurotensin (NT), anti-NT serum (ANTS), and naloxone (Nx) on both the pain threshold and electroacupuncture (EA) analgesia in rat was investigated in this study. The potassium iontophoresis-induced tail-flick was used to measure the pain threshold. NT administration induced an increase in pain threshold and enhanced EA analgesia. Injection of ANTS reduced the pain threshold significantly and diminished the effect of EA analgesia. Furthermore, pre-injection of Nx into PAG could weaken analgesia effect of NT and NT-EA analgesia. These results indicate that NT in PAG is involved in pain modulation and plays a role in EA analgesia. The effect of NT may be partly conducted by endogenous opiate peptides.

Acupuncture Analgesia↗
PubMed1997

[Somatostatin in NRM plays roles in inducing analgesia and enhancing electroacupuncture analgesia].

The effects of microinjection of somatostatin (SS), somatostatin depletor cysteamine (CS) and anti-somatostatin serum (ASSS) on the pain threshold (PT) and electroacupuncture (EA) analgesia were investigated in the rat. The potassium iontophoresis induced tail-flick was used to measure the pain threshold. The "Zusanli" were stimulated with EA. The results indicated that microinjection of SS into necleus raphe magnus (NRM), could elevate PT and enhance EA analgesia. PT and EA analgesia were decreased when SS in NRM was depleted by CS or neutralized by ASSS. These data revealed that SS in NRM plays important roles in inducing analgesia and enhancing electroacupuncture analgesia.

Acupuncture Analgesia↗
PubMed1997

[Ocular socket plasty with orbital implant of hydroxyapatite].

OBJECTIVE: To evaluate the clinical effect of a new surgical procedure to reconstruct socket with sclera-encapsulated hydroxyapatite after enucleation and evisceration. METHODS: Hydroxyapatite spheres were implanted primarily into auto-sclera capsule in 41 cases. Secondary implantation was performed with heterosclera-encapsulated ones in 9 cases. RESULTS: No inflammation, implant extrusion and implant dislocation occurred in 7-23 months (mean = 15.6 months) of follow-up. CONCLUSION: Satisfactory prothetic motility was obtained in all cases.

Adolescent↗
PubMed1997

[Role of leukotriene B4 in monocrotaline-induced pulmonary hypertension].

Monocrotaline (MCT) causes lung inflammation and chronic pulmonary hypertension associated with lung vascular thickening in rats. We hypothesized that leukotriene B4 (LTB4) and LTB4-induced accumulation of leukocytes in the lung play a role in MCT-induced lung disease, and therefore measured LTB4 and myeloperoxidase (MPO) levels in lung tissue of MCT-treated rats. Next, we examined the effect of an orally active LTB4 receptor antagonist (ONO4057) on MPO levels in lung tissue, on pulmonary hypertension, and on pulmonary vascular remodeling induced by MCT. Lung LTB4 and MPO levels had increased by 3 days after MCT injection. In the ONO4057-treated MCT rats, lung MPO levels were significantly lower than in the rats given MCT but not ONO4057. By the third week after injection. MCT had caused increases in mean pulmonary arterial pressure, in the ratio of right ventricular weight to left ventricle+septum weight (RV/[VS + S]), and in media wall thickness of the muscular arteries of the lung. Treatment with ONO4057, either for 3 weeks or during the first week after MCT injection, significantly reduced pulmonary hypertension, right ventricular hypertrophy, and lung vascular thickening induced by MCT. These results indicate that ONO4057 reduces both the accumulation of leukocytes in lung tissue and the chronic pulmonary hypertension induced by MCT, and they suggest a role for LTB4 in the inflammatory process that contributes to pulmonary hypertension and lung vascular remodeling induced by MCT in rats.

Animals↗
PubMed1997

[Increase in pulmonary vascular permeability caused by increased expression of Mac-1 on the surface of polymorphonuclear leukocytes].

We studied the expression of adhesion molecules on the surface of human polymorphonuclear leukocytes (PMNs). The effects of mechanical stimulation were measured with a flow cytometer and pulmonary vascular injury due to accumulation of PMNs in the lungs was assessed by a gravimetric method. The accumulation of PMNs in the lungs was studied by measuring the amount of myeloperoxidase. PMNs were stimulated by gentle agitation in a glass container for 10 s. Mac-1 (CD11b/CD18) was upregulated on the surface of PMNs that were mechanically stimulated. When unstimulated PMNs were exposed to isolated rat lungs, the filtration coefficient did not change from that under baseline conditions. However, when mechanically stimulated PMNs were exposed to isolated rat lungs, the filtration coefficient was about 5 times higher than that measured at baseline. When mechanically stimulated PMNs treated with anti-CD18 antibody were used, the increase in the filtration coefficient was completely blocked. The assay of myeloperoxidase revealed that PMNs stuck to isolated rat lungs only after stimulated PMNs were added. We conclude that when the adhesiveness of PMNs is increased by mechanical stimulation, these cells adhere to pulmonary vessels and increase pulmonary vascular permeability.

Animals↗