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Biomedical subjects

Y Cai

Publications and source records attributed to Y Cai.

At least 253 records · Page 14Linked to original sources
PubMed1995

Artificial neural network method for discriminating coding regions of eukaryotic genes.

This paper describes the application of artificial neural networks to discriminating the coding system of eukaryotic genes. We choose > 300 genes from eight eukaryotic organisms: human, mouse, rat, horse, ox, sheep, soybean and rabbit, from which we build up different discrimination models relevant to their promoter regions, poly(A) signals, splice site locations of introns and noose structures. The results shows that as long as the coding length is definite, the only correct coding region can be chosen from the large number of possible solutions discriminated by neural networks.

Animals↗
PubMed1995

Opposite actions of transforming growth factor-beta 1 on the gene expression of atrial natriuretic peptide biological and clearance receptors in a murine thymic stromal cell line.

The regulation of the gene expression of the atrial natriuretic peptide receptor (ANPR) subtypes, ANPR-A, ANPR-B, and ANPR-C, was investigated in a murine thymic stromal cell line, MRL 104.8a. When MRL 104.8a cells were cultured with transforming growth factor (TGF)-beta1, [125I]ANP binding sites increased with increasing dose of TGF-beta1. These binding sites were identified as ANPR-C by a displacement experiment with ANPR-C-specific ligand, C-ANF, and by the affinity cross-linking of the [125I]ANP binding sites with a chemical cross-linker to determine the molecular weight of the ANPR. This augmentation of the ANPR-C expression was elucidated to occur at the transcriptional level by Northern blot experiment, comparison of the relative amounts of mRNA by reverse transcription (RT)-PCR, and in vitro nuclear transcription assay. Conversely, the expression of the ANP biological receptors, ANPR-A and ANPR-B, was shown to be down-regulated by TGF-beta1. These data suggest that TGF-beta1 regulates the gene expression of ANPRs in the thymic stromal cells and that ANP and TGF-beta1 might affect the thymic stromal cell functions.

Animals↗
PubMed1995

Assignments of the genes for rat pituitary adenylate cyclase activating polypeptide (Adcyap1) and its receptor subtypes (Adcyap1r1, Adcyap1r2, and Adcyap1r3).

Chromosomal assignments of the genes for rat pituitary adenylate cyclase activating polypeptide (Adcyap1) and all of its receptor subtypes (Adcyap1r1, Adcyap1r2, and Adcyap1r3) were performed by PCR analysis of somatic cell hybrid DNAs. Adcyap1r1, Adcyap1r2, and Adcyap1r3 were localized to rat chromosomes 9, 4, 8, and 4, respectively.

Animals↗
PubMed1995

Endothelin-induced interleukin-6 production by rat aortic endothelial cells.

Endothelin (ET) produced by endothelial cells has recently been found to be a potent vasoconstricting hormone. In this paper, ET isopeptides, both ET-1 and ET-3, were shown to be potent stimulators of interleukin (IL)-6 production by a rat aortic endothelial cell clone, WAE-1. Semi-quantitative polymerase chain reaction analysis indicated that augmentation of IL-6 production is due to an increase in IL-6 messenger RNA level. Ligand binding assay indicated that most of the [125I]ET-1 binding sites correspond to ET receptor type A (ETAR). However, ET receptor type B (ETBR) was shown to be also present on this cell line by reverse transcription polymerase chain reaction using ETBR-specific primers and by ligand binding assay using [125I]ET-3, although the protein receptor level is much lower than that of ETAR. ET-1, but not ET-3, induced inositol 1,4,5-triphosphate production and an increase in intracellular Ca2+ concentration with similar dose response. These data suggest that ET-1 stimulates IL-6 production through ETAR-phospholipase C activation axis, whereas ET-3 stimulates IL-6 production through different signaling pathway. The results shown in this paper raise the possibility that ET plays a role in inducing inflammation in endothelium.

Animals↗
PubMed1995

Deodorization of laboratory animal facilities by ozone.

Deodorizing effect of ozone was investigated comparing two types of compact ozonizing apparatus made on an experimental basis. The concentrations of ammonia and trimethylamine were examined as an indicator for deodorizing effect of ozone in animal rooms of rats and guinea pigs at laboratory animal facilities of three different universities. Both of the ozonizing apparatus were able to remove ammonia and trimethylamine in animal rooms, with no significant difference in the performance of the two apparatus.

Ammonia↗
PubMed1995

Blood urea and amino acid concentrations in pigs of two breed combinations as affected by energy intakes.

Forty-eight barrows (61 kg), 24 Yorkshire x Landrace (YL) and 24 YL x Duroc x Hampshire (YLDH), were used to evaluate the effect of six dietary ME levels on concentrations of plasma urea nitrogen (PUN) and free amino acids. All pigs consumed equal amounts of each nutrient, except for energy. As energy intakes increased from 12.42 to 35.01 MJ/d of ME (34 to 97% of NRC recommendations), ADG increased linearly (P < .001) and concentrations of PUN decreased linearly (P < .01) and quadratically (P < .05). There was a tendency (P = .09) for an interaction of breed combinations and energy intakes on ADG. In general, increasing energy intake decreased plasma concentrations of essential amino acids and increased plasma concentrations of nonessential amino acids. Exceptions were a lack of change in plasma lysine and glutamic acid, an increase in histidine, and decreases in tyrosine and aspartic acid. Concentrations of most plasma amino acids were similar between the two breed combinations, but 9 of 27 amino acids that were measured were different (P < .05) between the breed combinations. The linear response of ADG was probably attained through a relatively constant lean-to-fat deposition ratio in the body over the levels of ME intakes. The curvilinear decline of PUN to increasing energy intakes was probably because at low energy intakes, amino acids were oxidized to furnish energy for maintenance and at increasing energy intakes there was increasing accretion of body proteins.

Amino Acids↗
PubMed1995

A nitro analogue of staurosporine and other minor metabolites produced by a Streptomyces longisporoflavus strain.

From the staurosporine-producing strain Streptomyces longisporoflavus R-19 various minor metabolites were isolated: They include a new compound with a nitro function in C-4' and other metabolites related to staurosporine. The new structures were elucidated by spectroscopic methods, mainly 1H NMR and 13C NMR and by comparison with TAN-1030A. The new compounds inhibited protein kinase C with IC50 values in the nanomolar range.

Alkaloids↗
PubMed1995

[Tolerance of reconstructive flaps to postoperative irradiation in oral and maxillofacial regions].

Eighty-three reconstructive flaps in oral and maxillofacial regions irradiated with a dose of 4000 to 7200 cGy were observed for a 2 year follow-up period. It was found that the rates of acute side effects including redswelling erosion and ulceration in the flaps were lower significantly than in neighbor oral mucosa (P < 0.01-0.05). The late radiation side effects of the flaps were uncommon also. The result showed that free flaps were well tolerated to postoperative irradiation of routine dose. Our studies indicate that the preoperative irradiation deficiency of blood supply or purulency were main reasons of the late radiation side effects, e.g. atrophy of epithelia, cicatrization or necrosis of the flap. Base on the results we have designed preventive measures.

Adult↗
PubMed1995

[Quantitative analysis of gamma-schizandrin in manganbao granules, a complex prescription of Chinese medicine].

This paper deals with a HPLC method for determining the content of gamma-schizandrin in Manganbao granules. Samples are extracted with haxane, re-dissolved in MeOH, chromatographed on HPLC (Column, Spheri-5 RP-18, 220 mm x 4. 6mm, mobile phase, 75% MeOH) and the main components can be easily isolated. Six samples were analyzed by calibration curve method. The results have shown that the quantitative analysis of gamma-schizandrin conducted in this way is convenient, fast and highly reproducible.

Antiviral Agents↗
PubMed1995

The rat homologue of the Wilson's disease gene was partially deleted at the 3' end of its protein-coding region in Long-Evans Cinnamon mutant rats.

LEC mutant rats exhibit an abnormal hepatic copper accumulation, due to the defection of the rat homologue of the Wilson's disease gene. In this study, we found a definitive evidence that the rat Wilson's disease gene of LEC rats was partially deleted at the 3' end of its protein-coding region, by performing Southern blot analysis. Furthermore, in Northern blot analysis, we confirmed that expression of the rat Wilson's disease gene was deficient in the liver of LEC rats. The partial deletion of the rat Wilson's disease gene should be responsible for the deficient expression of that gene in LEC rats.

Animals↗
PubMed1995

[Induction of differentiation by all-trans-retinoic acid in a human lung adenocarcinoma cell line].

All-trans-retinoic acid (RA) is a powerful differentiation-inducing reagent. We examined the effect of RA on malignant phenotype of human lung adenocarcinoma cell line GLC-82 in vitro. Treatment of GLC-82 cell with 10(-5)mol/L. RA for 1-7 days resulted in suppression of cell proliferation (33-55%), inhibition of colony formation in soft agar (97.5%), and a decrease of 3H-TdR incorporation (30-60%). Cytokinetic studies demonstrated that the cells arrested in G1/G0 phase increased from 36.0% to 72.4%, which is typical for cell differentiation. Human endothelial cell transglytaminase (TGase) was expressed persistently during RA treatment. Treatment of GLC-82 cell with RA gave rise to senescence and apoptosis gradually. The results indicated that induction of differentiation and modulation of gene expression can be achieved by RA treatment in human lung adenocarcinoma cell line GLC-82.

Adenocarcinoma↗
PubMed1995

[Conservative surgery and radiotherapy for early breast cancer].

Thirty-six patients with early stage breast cancer were treated by quadrantectomy, axillary dissection and radiotherapy (CSRT) between October 1987 and May 1990. The median follow-up was 48 months. Overall survival was 100%. 2 had local recurrence in the breast, both patients were stage IIB (T2N1), the number of positive node were 6/12 and 3/11, respectively. The cosmetic results of the breast are excellent and good in 91%. We concluded that CSRT provides good cosmetic results and better local tumor control for early breast cancer patients, but good results depend on strict adherence to indication of treatment, fair surgical techniques and radiotherapeutic measures.

Adult↗
PubMed1995

[Effects of dynorphin A (1-8) on cell cycle and total cellular protein during neuronal aging in vitro].

Serum-free culture of mouse neuroblastoma cells was used as the experimental model for the study of neuronal aging, with flow cytometry of cell cycle, DNA and total cellular protein as the indices of neuronal aging. After addition of dynorphin A (1-8) 10(-7) mol.L-1 into the culture medium, the following general tendencies were obtained: (1) The number of S and G2 + M phase cells was increased and the number of G1 phase cells decreased. (2) The total cellular protein in aged experimental neural cells decreased. The results implies that Dyn A (1-8) Produced effects on cell cycle, DNA and total cellular protein in the direction of delaying neuronal aging. The relation between Dyn A (1-8) and neuronal aging merits further investigation.

Animals↗
PubMed1995

[Study on the effect of endothelin and nitric oxide on DNA synthesis of pulmonary artery smooth muscle cells and modulation of hypoxia].

Increasing vasoconstriction and vascular remodeling of pulmonary vasculature are main characteristics of hypoxic pulmonary hypertension (HPH). Basal pulmonary circulatory tone is maintained by a dynamic balance of vasoconstrictors and vasodilators acting on the pulmonary vascular smooth muscle cells. Endothelin-1 (ET-1) and nitric oxide (NO) are the most important endothelium-derived vasoconstrictor (EDCF) and vasodilator (EDRF). In this report, we studied the effect of ET-1 and NO on hypoxic pulmonary vascular remodeling. We observed that ET-1 dose dependently increased DNA synthesis of pulmonary artery smooth muscle cells (PASMC), SNP, a NO generating drug, inhibited DNA synthesis of PASMC and its inhibitory effect was mediated by cGMP. Hypoxia increased the proliferative response of PASMS to ET-1 by stimulating autocrine of PASMC and decreased the inhibitory effect of SNP by reducing the activity of intra-cellular soluble guanylate cyclase. Based on the result, it is suggested that the balance of ET-1 and NO and regulation of hypoxia play important roles in hypoxic pulmonary vascular remodeling.

Animals↗
PubMed1995

[Structural changes of extra pulmonary artery and pulmonary arterioles of rats during chronic hypoxia and their significance].

The structural changes of extra pulmonary artery (PA) and pulmonary arterioles and their effects on the pulmonary arterial pressure (PAP) under chronically hypobaric hypoxia (5000 m) were studied. The results showed that (1) The endothelial edema of extra PA and pulmonary arterioles gradually reduced and the endothelial proliferation took place along with the prolongation of hypoxic exposure followed by the recovery of endothelium-dependent relaxation evoked by Ach from depression. This result suggested that the release of E-DRFs from endothelium increased with the structural changes of endothelium in the course of hypoxic exposure, which may be a reason why PAP did not increase any more after 21 to 40 of days exposure. However, the strengthened contraction of PA, the proliferation of cells on the vascular wall, and the muscularity of pulmonary arterioles being related to the hypoxic endothelium may produce a negative effect on decrease of PAP, resulting in persistently higher PAP. (2) The structural changes of pulmonary arteriole endothelium were more severe than those of extra PA endothelium, indicating that pulmonary arterioles might be more sensitive to the stimulation of hypoxia.

Altitude Sickness↗
PubMed1994

Carbon tetrachloride hepatotoxicity as a function of age in female Fischer 344 rats.

Severity of liver damage 24 h after intraperitoneal administration of carbon tetrachloride (0.2 ml/kg) was evaluated in female Fischer 344 rats aged 5, 14 and 28 months, i.e. in young adulthood, middle age and old age. Carbon tetrachloride-induced hepatotoxicity, as judged by the leakage of hepatic enzymes into the bloodstream and the disappearance of hepatic microsomal cytochrome P450, was much less severe in old rats than in young-adult rats. For example, serum sorbitol dehydrogenase (SDH) activity following carbon tetrachloride administration was 680 mumol/min/l in old rats compared with 1710 mumol/min/l in young-adult rats, and the loss of hepatic cytochrome P450 was 25% of the total amount in old rats compared with 50% of the total in young-adult rats. Spin trapping and electron spin resonance (ESR) spectroscopy were utilized to measure the conversion of carbon tetrachloride to trichloromethyl radicals in vivo. This primary bioactivation step occurred at similar rates in female rats aged 5, 14 and 28 months. In addition, the total nonheme iron contents in livers of rats in the three age groups were similar. Thus, the age associated attenuation of carbon tetrachloride-induced hepatotoxicity was not explained on the basis of decreased bioactivation to reactive species or decreased availability of iron for promotion of lipid peroxidation. The results suggest that other factors are important determinants of age-associated changes in sensitivity to toxic chemicals.

Aging↗
PubMed1994

Stimulation of interleukin-6 production by endothelin in rat bone marrow-derived stromal cells.

Endothelin (ET) produced by endothelial cells has recently been found to be a potent vasoconstricting hormone. In this report, ET is shown to be a potent stimulator of interleukin-6 (IL-6) production by rat bone marrow (BM)-derived stromal cells. It was also shown that ET increased the level of mRNA for IL-6 in these cells. The two types of ET receptor (R), ETAR and ETBR, were shown to be expressed on both BM-derived stromal cells in culture and ex vivo in BM tissue, suggesting that ET works as a physiologic stimulator of IL-6 production in the BM. It was shown that ETAR is coupled to phospholipase C activation, leading to the production of inositol 1,4,5-trisphosphate (IP3) and 1,2-diacylglycerol (DAG) as second messengers in BM-derived stromal cells. This was corroborated by data showing that IL-6 production in these cells was induced by combined stimulation with ionomycin and phorbol myristate acetate, thereby bypassing the effects of IP3 and DAG, respectively. This is the first report on the hormonal regulation of IL-6 production by BM stromal cells, indicating that hematopoiesis is subject to endocrinologic regulation under physiologic conditions. ET has recently been reported to be produced by macrophages in response to bacterial lipopolysaccharide and human immunodeficiency virus-1 glycoprotein 120. These facts, taken together with our findings, raise the possibility that ET shares the same role of IL-1 as a local cytokine, mediating an intercellular signal between macrophages and BM stromal cells in response to bacterial or viral stimulation.

Animals↗