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Biomedical subjects

C Song

Publications and source records attributed to C Song.

At least 109 records · Page 6Linked to original sources
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↗
PubMed1997

Wound modulation via sclerotherapy and tissue adhesion. Observations and discussion.

Fluid accumulation in a 'dead space' after surgery or trauma predisposes the area involved to delayed healing. The fluid may promote inflammatory mediators and other wound-modulating factors, which encourages the continued existence of the dead space. Tissue adhesion by means of agents such as tetracyclines has long been described. With this concept, tissue adhesion has been accomplished with varying success in diverse clinical situations involving non-healing wounds and prophylactically in seroma-prone areas. A total of 69 patients were treated and monitored. The most impressive response to tetracycline tissue adhesion in this study was seen in intra-oral sites, with rapid closure of wounds. More complex wounds such as orocutaneous fistulas or wounds of a more chronic nature such as pressure sores did respond but took longer to resolve. The lateral thigh was found to be the most difficult and unresponsive area to treat (particularly after delayed presentation). Successful prophylactic use of tetracycline in seroma-prone areas (latissimus dorsi/parascapular flaps, etc.) is also described.

Anti-Bacterial Agents↗
PubMed1997

RNA promoters located on (-)-strands of a subviral RNA associated with turnip crinkle virus.

Satellite (sat-) RNA C, one of the nonessential subviral RNAs of turnip crinkle virus (TCV), is dependent on the TCV-encoded RNA-dependent RNA polymerase (RdRp) for its replication. Earlier work showed that a stem-loop structure at the 3' end of (+)-strand sat-RNA C is required for synthesis of (-)-strands in vitro using a partially purified, template-specific TCV RdRp (Song C, Simon AE, 1995, J Mol Biol 254:6-14). Cis-sequences on (-)-strands of sat-RNA C that can serve as separate promoters in vitro have now been defined. Two promoter sequences are located on (-)-strand sat-RNA C, one comprising 11 bases located near the 3' end, and the other consisting of 14 bases located 41 bases from the 5' end. Both promoter sequences contain multiple consecutive C residues followed by multiple consecutive purines and have no obvious secondary structure, suggesting that, along with hairpin structures, specific primary sequences can be recognized by the TCV RdRp. The 3'-proximal promoter sequence directed synthesis from the 3' terminus using (-)-strand templates with the natural sat-RNA 3' end (AUCCC-3'). When plasmid-derived bases were present at the 3' ends of the templates, both promoter sequences could direct the RdRp to initiate transcription internally at the multiple consecutive C residues within the promoters. This result suggests that multiple consecutive C residues are important for transcription initiation and that natural 3'-end sequences, when located at 3' termini, help the RdRp to initiate at the 3' end of the molecule.

Carmovirus↗
PubMed1996

Local intraluminal infusion of biodegradable polymeric nanoparticles. A novel approach for prolonged drug delivery after balloon angioplasty.

BACKGROUND: Several perfusion balloon catheters are under investigation for local drug delivery; however, sustained tissue drug levels are difficult to achieve with these techniques. To overcome this problem, sustained-release, biodegradable nanoparticles represent a potential alternative for prolonged local delivery. METHODS AND RESULTS: A biodegradable polylactic-polyglycolic acid (PLGA) copolymer was used to formulate nanoparticles. Fluorescent-labeled nanoparticles were intraluminally administered in a single, 180-second infusion after balloon injury in the rat carotid model. Localization and retention at different time points and biocompatibility of nanoparticles were evaluated. To evaluate the potential of the system in the prevention of neointimal formation, dexamethasone was incorporated into the particles and delivered locally as above. Nanoparticles were seen in the three layers of the artery at 3 hours and 24 hours. At 3 days, they were mainly present in the adventitial layer, decreasing at 7 days, with no fluorescent activity at 14 days. The PLGA nanoparticles appeared to be fully biocompatible. In the dexamethasone nanoparticle study, a significant amount of dexamethasone was present in the treated segment for up to 14 days after a single infusion, with no plasma levels detected after the first 3 hours. There was a 31% reduction in intima-media ratio in animals treated with local dexamethasone nanoparticles compared with control. CONCLUSIONS: Nanoparticles successfully penetrated into the vessel wall and persisted for up to 14 days after a short, single intraluminal infusion. Local administration of nanoparticles with incorporated dexamethasone significantly decreased neointimal formation. This methodology appears to have important potential for clinical applications in local drug delivery.

Angioplasty, Balloon, Coronary↗
PubMed1996

The effects of central administration of neuropeptide Y on behavior, neurotransmitter, and immune functions in the olfactory bulbectomized rat model of depression.

The effects of subchronicly administered neuropeptide Y (NPY) intracerebroventricularly on behavioral, neurochemical, and immunological parameters were examined in sham operated and olfactory bulbectomized (OB) rats. In the untreated OB rats, an increase in ambulation, rearing, grooming, and defecation scores was found in the novel stressful environment of an "open field." Following 7 days of NPY administration, these behaviors were largely attenuated. In the elevated plus-maze apparatus, OB rats showed an increase in the number of entries into the open arms and time spent on the open arms compared with sham operated animals; NPY had no significant effect on the behavior of either sham operated or OB animals in this test. A decrease in the NA concentration was found in the amygdloid cortex of OB rats. NPY infusion significantly increased the NA concentration in amygdala, reduced 5-HIAA but increased 5-HT concentrations in the hypothalamus, and increased the dopamine level in the hippocampus. NPY administration also reversed the suppression of lymphocyte proliferation in the OB rat. However, the changes in the differential white blood cell count and the elevated phytohemagglutinin-induced chemiluminescence of mononuclear cells in the OB were not altered by NPY. These results suggest that NPY may have a modulatory effect on some behavioral, neurotransmitter, and immune aspects of the OB rat model of depression.

Animals↗
PubMed1996

Stress and the immune system in the etiology of anxiety and depression.

There is clinical and experimental evidence that various aspects of the immune and endocrine systems are severely compromised in chronic stress and depression. For example, it has been shown that a reduced lymphocyte response occurs to mitogens in depressed patients, effects that are not reversed by chronic antidepressant treatment. By contrast, monocyte phagocytosis is increased, while neutrophil phagocytosis is decreased in depressed patients. Such changes are normalized by effective antidepressant treatment. The results of such studies and others that demonstrate alterations in noncellular immune processed in depression indicate that the changes in immune function correlate with the severity and duration of the external and/or internal stressful stimuli. There is evidence that some of the immune changes are a reflection of increased plasma glucocorticoids that characterize both stress and depression. However, it is also apparent that the cytokines, prostaglandins, and corticotrophic releasing factor (CRF) also play an important role in initiating the behavioral and pathophysiological changes that are characteristic of both depression and chronic stress. This review attempts to critically assess the interplay between CRF, the immune and neurotransmitter systems, and behavior in chronic stress and depression.

Animals↗
PubMed1996

Behavioural and immunological effects of the antihistamine terfenadine in olfactory bulbectomized rats.

The effects of chronic treatment with the non-sedative histamine H1 receptor antagonist terfenadine (5 mg/kg, i.p.) for 16 days on some behavioural and immunological parameters were studied in the olfactory bulbectomized (OB) rat model of depression. In the open field apparatus, OB rats showed a significant increase in ambulation and rearing scores. Following terfenadine treatment, this hyperactivity was significantly attenuated. In untreated OB rats, neutrophils phagocytosis and lymphocyte proliferation were significantly suppressed. Terfenadine administration markedly reversed the suppression of these immunological parameters in the treated OB animals, but did not reverse the abnormalities in the differential white blood cell count caused by bulbectomy. These results suggest that the histamine H1 receptor antagonist terfenadine may have antidepressant properties and that terfenadine is effective in reversing some of behavioural and immune changes in the olfactory bulbectomized rat model of depression.

Animals↗
PubMed1996

Human immunodeficiency virus infection in an emergency hand service.

A study prompted by the high number of human immunodeficiency virus (HIV) patients in the South African population was performed to evaluate the incidence of HIV in patients attending our Emergency Hand Service. Over a 6-month period, more than 500 consecutive emergency patients were tested for HIV. In our series, 24 patients tested HIV-positive. Of these, 14 presented with hand sepsis and 10 with hand injuries. Bacteriology was performed on all patients with sepsis to document bacteria type and sensitivity. CD4 counts (T4 lymphocyte counts) were done on 12 patients to assess immunocompetence. Other factors examined included hospital stay, number of operations, postoperative morbidity, and mechanism of injury. Results indicate that septic HIV patients spent more time in the hospital and required more operations than septic non-HIV patients. Furthermore, of all of the population of emergency hand patients, a larger percentage of HIV-positive persons than HIV-negative persons was likely to be seen for infection.

Adult↗