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Biomedical subjects

C Song

Publications and source records attributed to C Song.

At least 127 records · Page 7Linked to original sources
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↗
PubMed1996

[The changes of hemodynamics in ocular trauma and treatment with compound anisodine].

OBJECTIVE: To study the changes of hemodynamics in human ocular trauma and treatment with compound anisodine. METHODS: 34 cases with ocular trauma were examined by rheoophthalmography (ROG) and Doppler ultrasonography (DUSG). RESULTS: It appeared that the wave amplitudes of ROG were lower in both injured and contralateral eyes, which indicated the ocular blood flow was reduced. The speed of systolic blood flow in ophthalmic artery (OA), the value of systolic peak frequency (PK) in internal carotid artery (ICA) and common carotid artery (CCA) in DUSG were increased, indicating that there were certain degrees of blood vessel spasm in OA, ICA and CCA. CONCLUSION: Ocular trauma not only directly impairs the vasomotor function of injured eyes but also affects the vasomotor function of contralateral eyes and the function of the autonomic nervous system or cerebral cortex by consensual reaction. The treatment by compound anisodine may effectively relieve and restore the above changes and improve the visual function. ROG and DUSG are sensitive and objective to estimate the changes of hemodynamics and evaluate the therapeutic effect in ocular trauma.

Adolescent↗
PubMed1996

[Restoration of external auditory canal by filling mastoid cavity with carbon pellet].

To prevent infection of an open mastoid cavity after mastoidectomy and improve hearing, the external auditory canal had been maintained on 72 cases (73 ears) by filling mastoid cavity with carbon pellet. The average duration of dry ear after operation was 25 days with a dry ear rate being 98.6%. No phenomenon of rejection and falling out appeared within 1-7 years follow-up. Carbon pellet has advantages of chemical stability, nontoxicity, good histocompatability, anti-fatigue characteristic in body fluid, and anti-corrosive effect against acid, base and salt.

Adolescent↗
PubMed1996

[Nucleotide sequence of HLA-DQA1 promoter region (QAP) in a lung cancer patient].

The HLA-DQA1 allele and nucleotide sequence of HLA-DQA1 promoter region (QAP) in a patient with IDDM complicated lung cancer have been identified by PCR/SSCP, PCR/SSCP and PCR/sequencing. The results showed that: (1) All of the lung cancer patient and his family members carried HLA-DQA1* 0301/0501 alleles. (2) a single base substitution G-->A at position -155 and deletion CAA at position -161 to -163 occurred in the patient. These results suggest that the mutation of HLA-DQA1 promoter region may modulate HLA-DQA1 gene expression by trans-acting factors binding to variant cis-acting elements and may be responsible for pathogenesis of lung cancer.

Alleles↗
PubMed1996

[An experimental study on compound anisodine III for softening scar of mouse skin after burn].

OBJECTIVE: The aim of this study was to investigate the mechanism of compound anisodine (CA) III which can rapidly soften the cicatrized tissue in clinical practice. METHODS: 2 mol/L NaOH was applied onto the back of 36 mice for one minute to induce deep grade skin burn injury. After 1 week local cicatrization occurred. The mice were randomly divided into 3 groups: 1 ml saline was used in group I as control, hyaluronidase 150 U dissolved in 1 ml 2% procaine was used in group II and 0.005% CA 0.1 ml in 2% procaine 1 ml with hyaluronidase 150 U was used in group III. Subcutaneous injection once every other day for two weeks was the method of drug administration in all the 3 groups and then all the rats were euthanized. The burned skin was sectioned for HE and modified Masson's stains. RESULTS: Histopathology revealed there were epidermis proliferation, keratinization and fibrosis with disorderly arranged collagenous fibers invading into muscles and a large amount of inflammatory cells infiltrating the lesion in groups I and II. However, the skin was nearly normal in group III. CONCLUSIONS: CA III can inhibit the epidermic and collagenous proliferation, improve the tissue blood supply and have antiinflammatory effect to prevent scar formation and promote epidermic repair in the skin.

Animals↗
PubMed1995

Behavioral, neurochemical, and immunological responses to CRF administration. Is CRF a mediator of stress?

The effect of subacute intracerebroventricular (icv 0.1, 0.5, and 1.0 microgram) administration of corticotropin-releasing factor (CRF) for 5 days on behavior, neurotransmitter concentrations, and immune functions was studied in rats. The results showed that CRF administration produced a dose-dependent increase in locomotor activity in the "open field" test compared with controls; rearing scores were also significantly increased. In the elevated plus maze apparatus, rats given 1.0 microgram CRF spent considerably less time on the open arms when compared with controls. Following 0.5 and 1.0 microgram of CRF infusion, the concentrations of noradrenaline (NA), dopamine (DA) and 5-hydroxy indole acetic acid (5-HIAA) were significantly increased in the hypothalamus. There was no significant change in the concentrations of neurotransmitters in the other brain regions. CRF administration also produced a dose-dependent increase in the levels of corticosterone in the serum. The immunological results clearly showed that subacute icv CRF administration caused a reduction of lymphocyte proliferation, a decrease in the percentage of lymphocytes, and an increase in neutrophil percentage in the differential white blood cell (WBC) count, a decrease in neutrophil phagocytosis, and elevated leucocyte adhesiveness/aggregation (LAA) compared with control animals. These results suggest that icv subacute administration of CRF has anxiogenic effects, increases biogenic amine concentrations in the hypothalamus, and changes in some aspects of immune functions that may reflect the stress-inducing properties of the peptide. These effects are time and dose dependent.

Animals↗
PubMed1995

Requirement of a 3'-terminal stem-loop in in vitro transcription by an RNA-dependent RNA polymerase.

Partially purified RNA-dependent RNA polymerase (RdRp) isolated from plants infected with turnip crinkle virus (TCV) is capable of template-dependent synthesis of TCV-associated RNAs. To determine the cis-sequences required for the synthesis of TCV satellite (sat-) RNA C (-) strands in vitro, templates containing interior deletions were subjected to transcription using RdRp-active fractions. Results indicated that the promoter for (-)-strand synthesis was contained within the 3'-terminal 29 bases of the (+)-strand. Structural probing by enzymatic digestion and chemical modification revealed the presence of a hairpin structure within this terminal region. Compensatory exchanges of four bases in the lower stem or alterations in the sequence and size of the loop region did not affect in vitro transcription, implying that the primary sequence in the loop and lower part of the stem is not important for interaction with the viral RdRp. However, single mutations in the base of the stem or double mutations in the upper stem strongly reduced template activity in vitro, suggesting that the stability of the hairpin is an important functional consideration. Relocation of the 3'-terminal 37 bases containing this stem-loop to inactive template RNA rendered the resultant hybrid RNA competent for in vitro transcription by RdRp activity, suggesting that the promoter for (-)-strand synthesis in vitro is completely contained within the 3'-terminal region.

Base Sequence↗