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Biomedical subjects

C Song

Publications and source records attributed to C Song.

At least 145 records · Page 8Linked to original sources
PubMed1995

[Rapid determination of the value-determining components in sausage products by near-infrared transmission spectroscopy].

A rapid method for the simultaneous determination of water, fat, crude protein, connective-tissue-protein and connective-tissue-protein free meat protein in sausage products with the help of near-infrared transmission spectroscopy (NIT) is presented. The calibrations for the each constituent were achieved with the chemometric method "partial least squares" (PLS) and validated with the added samples. Correlation coefficients between the reference methods and NIT were > or = 0.95 for water, fat, crude protein and connective-tissue-protein frei meat protein, and > or = 0.86 for connective-tissue-protein. The precision of NIT was comparable with the reference methods.

Animals↗
PubMed1995

Rat brain cannabinoid receptors are N-linked glycosylated proteins.

To study the N-linked glycosylation properties of the CB1 receptor, rat brain membranes were treated with exo- and endoglycosidases. For visualizing CB1 receptors, an antipeptide antibody was raised against the N-terminal 14 amino acids and used to specifically detect the protein by Western blotting. We found that the apparent molecular weight of mature CB1 receptors was 64 kDa. Treatment of membranes with endoglycosidase F shifted the 64 kDa band to the 59 kDa and 53 kDa bands. The latter is consistent with the calculated molecular weight of deglycosylated CB1 receptors. Treatment of membranes with endoglycosidase H and alpha-mannosidase partially shifted the 64 kDa band to 53 kDa band, indicating a portion of the oligosaccharides was of the high mannose type. These data confirmed that the CB1 receptors in brain are N-linked glycoproteins with heterogeneous carbohydrate composition. Among three potential N-linked glycosylation sites on the N-terminus of the CB1 receptor, only two sites are actually glycosylated.

Animals↗
PubMed1995

Superantigenic exotoxin production by isolates of Staphylococcus aureus from the Kawasaki syndrome patients and age-matched control children.

Nineteen strains of Staphylococcus aureus were isolated from the throat or the tooth surfaces of 19 cases amongst 127 patients with Kawasaki syndrome (KS) during the acute phases and 11 S. aureus isolates were obtained from five of 17 diseased controls and six healthy controls. The production of exotoxins, particularly superantigenic toxic shock syndrome toxin-1 (TSST-1), coagulase serotype, pigment production, haemolytic activity and tryptophan auxotrophy of these isolates were compared. Among 10 KS S. aureus strains isolated in 1990-1991, five (50%) secreted TSST-1, a higher frequency than two (18%) of 11 control isolates. In contrast, none of the nine KS strains collected in 1984 produced TSST-1. Four of five TSST-1-secreting KS strains produced white or white to golden pigmentation, whereas the two control strains capable of TSST-1 production formed golden colonies. There were no noticeable differences between S. aureus strains from KS patients and control children in the production of staphylococcal exotoxins A-E, coagulase serotype, haemolysis of sheep erythrocytes and tryptophan auxotrophy. The pathological or aetiological role of a new TSST-1-secreting S. aureus clone in patients with KS was not confirmed.

Bacterial Toxins↗
PubMed1995

Synthesis of novel products in vitro by an RNA-dependent RNA polymerase.

RNA-dependent RNA polymerase from turnip crinkle virus-infected turnip transcribes both strands of a virus-associated satellite RNA, sat-RNA C (356 bases), in vitro. While both plus- and minus-strand sat-RNA C can direct the synthesis of full-length complementary-strand products, transcription of minus-strand RNA also generates two non-template-sized products, L-RNA and S-RNA (C. Song and A. E. Simon, Proc. Natl. Acad. Sci. USA 91:8792-8796, 1994). Here we report that synthesis of L-RNA and S-RNA results from terminal elongation of the 3' end of the template. L-RNA has a panhandle structure and is composed of minus-strand template covalently linked to newly synthesized RNA complementary to its 5' 190 bases. S-RNA is composed of template covalently linked to its full-length complementary strand. All minus-strand templates tested yielded S-RNA. However, synthesis of L-RNA was affected by deletion of the 3' end of the minus-strand template or several internal regions and base alterations near the 5' end or in an internal sequence immediately upstream from the template-product junction that could potentially form a heteroduplex with the 3' end. Furthermore, mutations that disrupted or restored a stem-loop involved in RNA recombination in vivo affected the level of L-RNA produced in vitro, suggesting that the mechanisms for intramolecular formation of panhandle RNAs and intermolecular RNA recombination involve similar features.

Base Sequence↗
PubMed1995

[Effects of prostaglandin E1 (PGE1) on pulmonary hypertension and lung vascular remodeling in a rat monocrotaline model of human pulmonary hypertension].

Prostaglandin E1 (PGE1) has been shown to be a potent pulmonary vasodilator in humans and in many animals. The effects of PGE1 on the development of pulmonary hypertension and on pulmonary vascular remodeling were studied in a rat monocrotaline (MCT) model of human pulmonary hypertension. By 3 weeks after injection, MCT (80 mg/kg S.C.) had resulted in high values of mean pulmonary arterial pressure and of the ratio of right ventricular weight to left ventricle+septum weight (RV/LV+S). PGE1 inhibited the development of pulmonary hypertension (300 micrograms/kg) and right ventricular hypertrophy (300 and 100 micrograms/kg) induced by MCT. Three weeks after the injection, the media walls of pulmonary arteries in lungs from rats given MCT were significantly thicker than those from lungs of control rats. PGE1 (300, 100, and 30 micrograms/kg) resulted in significantly less of this morphologic change, in a dose-dependent manner. These results indicate that PGE1 inhibits the development of pulmonary hypertension associated with lung vascular thickening induced by MCT. PGE1 may be useful for the treatment of pulmonary hypertension in humans.

Alprostadil↗
PubMed1995

[An experimental study on the integrated effects of heat-cleaning and detoxifying drugs and fire-purging drugs used in combination].

Heat-cleaning and detoxifying drugs and fire-purging drugs used in combination have been proved able to restore the endotoxin-induced deviant of HCT, blood viscositites, PTT and fibrinolytic activity, and reduce the blood content of both endotoxin and PGE2 in rabbits. In addition, the combination can also decrease the pes swelling percentage in rats as well as evans blue extravasation volume in mice. In practice, however, it should be noted that the bitter and cold qualities of these two kinds of drugs may be harmful to health.

Albumins↗
PubMed1995

[Analysis of HLA-DRB1 alleles in patients with IDDM].

HLA-DR association with IDDM in local population in Beijing was studied by PCR/SSP typing. The frequency of HLA-DR9 was significantly higher in diabetic patients (30.3% [45/148] vs 17.92% [38/212], chi 2 = 6.97, P < 8.3 x 10(-3)). DR3 was higher in diabetic patients in this study (7.0% [10/148] vs 2.36% [5/212], chi 2 = 3.19, P > 0.05) and DR2 was lower in patients with IDDM (7.4% [11/148] vs 19.8% [42/212], chi 2 = 9.67, P < 1.9 x 10(-3)). These results suggest that DR9 and DR3 both were positively associated with IDDM, but DR2 was negatively associated with IDDM.

Adolescent↗
PubMed1995

[The effect of intrathecal injection of neurotensin on acupuncture analgesia in rats].

The influence of intrathecal injection of Neurotensin (NT) and Anti-NT serum (ANTS) on pain threshold, and electroacupuncture (EA) analgesia in the rat was investigated. The tail-flick induced by potassium iontophoresis was used to measure the pain threshold. The increase of pain threshold was observed within 100 min, after NT injection (2 micrograms), and it was more effective than that of the ACSF injection (P < 0.01). The NT administration could also enhance the EA analgesia. On the contrary, the pain threshold was decreased in ANTS group as compared with that of ACSF control group. The ANTS administration could decreased the role of EA analgesia. Our data show that NT in spinal cord may play an important role in the EA analgesia.

Acupuncture Analgesia↗
PubMed1994

Ubiquitous receptor: a receptor that modulates gene activation by retinoic acid and thyroid hormone receptors.

The cDNA for a member of the nuclear receptor family was cloned and named ubiquitous receptor (UR), since UR protein and mRNA are detected in many cell types. Rat UR/human retinoid X receptor alpha (hRXR alpha) heterodimers bound preferentially to double-stranded oligonucleotide direct repeats having the consensus half-site sequence AGGTCA and 4-nt spacing (DR-4). Coexpression of UR in COS-1 cells inhibited the stimulation of chloramphenicol acetyltransferase (CAT) reporter gene expression by hRXR alpha and human retinoic acid receptor alpha in the presence of all-trans-retinoic acid when DR-4 (but not DR-5) was present upstream of the promoter of a CAT reporter gene (DR-4-CAT). UR expression also inhibited the activation of a DR-4-CAT reporter gene by hRXR alpha and 9-cis-retinoic acid or by thyroid hormone receptor beta in the presence of thyroid hormone. However, in the absence of 9-cis-retinoic acid, UR in combination with hRXR alpha stimulation DR-4-CAT expression. Coexpression of thyroid hormone receptor markedly reduced this stimulation in the absence of thyroid hormone. UR may play an important role in normal growth and differentiation by modulating gene activation in retinoic acid and thyroid hormone signaling pathways.

Amino Acid Sequence↗
PubMed1994

RNA-dependent RNA polymerase from plants infected with turnip crinkle virus can transcribe (+)- and (-)-strands of virus-associated RNAs.

RNA-dependent RNA polymerase (RdRp) was solubilized from membranes of turnip infected with turnip crinkle virus (TCV), a single-stranded, monopartite RNA virus. The RdRp activity could be separated into three peaks by Sephacryl S500HR chromatography. RdRp from peak I, which contained substantial amounts of endogenous TCV genomic RNA, and peak II were template-specific, synthesizing full-length complementary strands of exogenous TCV subviral RNAs but not control RNA templates. Peak III RdRp was nonspecific, synthesizing full-sized products for all added RNA templates. Peak II RdRp transcribed several different TCV satellite (sat) and defective interfering RNA templates in both (+)- and (-)-sense orientations but did not transcribe (+)-strands of satellite RNAs associated with unrelated viruses. Monomeric-length sat-RNA C was synthesized from a template containing as many as 220 nonsatellite bases at the 3' ends of either (+)- or (-)-strands, indicating that the RdRp was able to recognize 3'-end sequences in an internal location. Deletion of 95-242 bases from the 3' end of (+)-strand sat-RNA C abolished the synthesis of template-length product. However, transcription of template-length products was not affected by the deletion of at least 257 bases from the 3' end of (-)-strand sat-RNA C template (leaving only the 100 5'-terminal residues), implying that different mechanisms exist for synthesis of (+)-and (-)-strand satellite RNA in vitro.

Plant Viruses↗
PubMed1994

Kainic acid stimulates uptake of divalent cations in postnatal cochlear neurons.

Excitatory amino acids were tested for their ability to induce cobalt uptake in cochlear explants of spiral ganglion neurons. Explants were taken from postnatal day 5 hamsters. Compared with NMDA and quisqualate, kainic acid (KA) stimulated the greatest amount of Co2+ uptake within spiral ganglion neurons as indicated by precipitation of the Co2+ accumulation and relative optical density measurements. Both L-glutamate and KA stimulation were blocked by non-NMDA receptor antagonists kynurenate and DNQX. Nifedipine, a dihydropyridine-sensitive calcium channel blocker, also partially inhibited Co2+ uptake. These data suggest that a mixed population of NMDA and non-NMDA receptors are present. Additionally non-NMDA receptors may have a role in cochlear synaptic maturation.

Animals↗
PubMed1994

Central sympathetic control of spinal endothelin release in the rat.

Endothelin and its receptors have been identified in the spinal cord. Intrathecal administration of endothelin-3 produces hypotension in anesthetized rats. The present study was designed to identify whether endothelin-3 is released upon changes in sympathetic nervous activity. Endothelin-3-like immunoreactivity in spinal superfusates was directly correlated with resting arterial pressure. Endothelin-3 levels were enhanced by hypothalamic stimulation and by hemorrhage-induced hypotension and reduced by nitroprusside-induced hypotension. These findings suggest that sympathetic activation enhances endothelin-3 release but that nitroprusside may act directly to suppress release. We propose that endothelin-3 plays a role in spinal regulation of sympathetic outflow.

Anesthesia↗