Biomedical subjects

C Yin

Publications and source records attributed to C Yin.

At least 19 recordsLinked to original sources

PubMed2002

[Functional analysis of SpltMNPV envelope protein SL136].

Our previous research showed that the Spodoptera litura multinucleocapsid nucleopolyhedrovirus (SpltMNPV) Sl136 product had a function to befused with membrane when expressed alone. In this study, the Sl136 and its product were characterized. RT-PCR results showed that Sl136 could be transcribed at 6 hpost infection, indicating it was an early gene. Then the antiserum against SL136 protein was generated and utilized to verify that SL136 was a BV envelope protein, by using SDS-PAGE and Western blot. Two main protein bands in SpltMNPV-infected Sl-zsu-1 cells were detected; their molecular weights were about 86 kD and 65 kD, respectively. It was found that the size of smaller band coincided with amajor band of BV envelope proteins. SL136 protein was transferred to cell surfaces both in SpltMNPV-infected Sl-zsu-1 cells and recombinant Bac-Sl136-infected Hi5 cells, as detected by cell ELISA(cell enzyme-linked immunosorbant assay, CELISA). From the bioassay results, it was found that furin cleavage of SL136 was not necessary for viral propagation, and inhibition of its glycosylation decreased the BV virulence.

Animals↗

PubMed2001

Immunolocalization and possible effect of a moth allatotropin-like substance in a fly, Phormia regina (Diptera: Calliphoridae).

Insect allatotropin upregulates the biosynthesis of juvenile hormones by the corpus allatum. We raised two rabbit antisera against the allatotropin of Manduca sexta (Mas AT) using a synthetic, multiple-antigenic-peptide that contains a branching heptalysine core and eight Mas AT molecules. Both antisera recognized specifically the same neurons in the larval brain, frontal ganglion and terminal abdominal ganglion of M. sexta as previously reported by others. Immunoassay showed reactivity specific to the Mas AT. Very low or nearly no cross-reactivity was found for two Mas AT-like peptides, a myotropin from Locusta migratoria and a Mas AT-like peptide deduced from the DNA sequence of Aedes aegypti, respectively. Immunopositive neurons also were identified in adult Phormia regina, Dacus dorsalis, Oncopeltus fasciatus, and Mythimna loreyi, and in larval M. loreyi, Bombyx mori, and Andraca bipunctata. At 20 pmol per 25 µl incubation medium (i.e. 8x10(-7) M), synthetic Mas AT significantly stimulated in vitro juvenile hormone biosynthesis by the corpus allatum of adult, sugar-fed females of P. regina to 2.64-fold that of controls. Thus, this study provides the first demonstration that at the higher end of the physiological concentration range, the Mas AT has allatotropic effect in vitro to CA of non-lepidopterans. However, in vivo functions of Mas AT and/or Mas AT-like peptide in P. regina remain to be defined.

Journal Article↗

PubMed2001

Simultaneous quantitative UV spectrophotometric determination of multicomponents of amino acids using linear neural network.

Simultaneous determination of multicomponents of six amino acids with a novel chemometric technique-a linear neural network (LNN) algorithm is reported in this study. Based on the data correlation coefficient and standard deviation method, 17 representative wavelength points are selected from the original UV spectral data (343 points) as the original input patterns for LNN to build a neural network model. The results obtained only by iterating 15 times is satisfying, with a correlation coefficient of 0.999 and a relative small standard deviation.

Algorithms↗

PubMed2001

Slow aging during insect reproductive diapause: why butterflies, grasshoppers and flies are like worms.

Diapause is a state of arrested development accompanied by physiology for somatic persistence. Diapause is common in many invertebrates and is familiar to biogerontology in the context of Caenorhabditis elegans dauer. Among insects, diapause may occur in embryos, larvae, pupae or adults. At the adult stage, reproductive diapause arrests development of oogenesis, vitellogenesis, accessory gland activity, and mating behavior. Reproductive diapause has been well studied in monarch butterflies, several grasshoppers, and several Diptera, including Drosophila and Phormia. In monarchs and in grasshoppers, reproductive diapause physiology has been experimentally induced by the surgical removal of the corpora allata, the source of adult juvenile hormone; allatectomy in each case was found to double adult longevity. Among Drosophila, the endemic D. triauraria of Japan, and D. littoralis of Finland over-winter as adults in reproductive diapause. How D. melanogaster winter is poorly understood, but reproductive diapause can be cued by cool temperature. In laboratory studies, the mortality rates of post-diapause D. melanogaster are similar to rates of newly enclosed, young flies. This implies that senescence during diapause is slow or negligible. Slow aging during the diapause period may involve elevated somatic stress resistance as well as reallocation of resources to somatic maintenance. Reproductive diapause in Drosophila is proximally controlled by down regulation of juvenile hormone, a phenotype that is also produced by mutants of the insulin-like receptor InR, homologue of C. elegans daf-2. We propose neuroendocrine control of reproductive diapause in D. melanogaster that includes phenotypic plasticity for rates of senescence.

Aging↗

PubMed2001

In vitro stimulation with a non-peptidic alkylphosphate expands cells expressing Vgamma2-Jgamma1.2/Vdelta2 T-cell receptors.

The majority of peripheral blood gammadelta T cells in healthy adult humans express the Vgamma2/Vdelta2 T-cell receptor (TCR) and generate TCR-mediated, major histocompatibility complex (MHC)-unrestricted proliferative responses to low molecular weight alkylphosphates. Vgamma2/Vdelta2 populations after antigen proliferation maintained diversity in the CDR3s of Vgamma2 mRNA, indicating that the response was polyclonal or oligoclonal, and were enriched for Vgamma2 TCR chains containing the Jgamma1.2 segment. Alkylphosphate stimulation further skewed an already biased peripheral blood gammadelta T-cell population and increased the abundance of Vgamma2-Jgamma1.2/Vdelta2 T cell receptors, suggesting similarities between the alkylphosphate response and peripheral selection mechanisms shaping this repertoire in human beings.

Amino Acid Sequence↗

PubMed2001

Selective inactivation of p53 facilitates mouse epithelial tumor progression without chromosomal instability.

We examined the selective pressure for, and the impact of, p53 inactivation during epithelial tumor evolution in a transgenic brain tumor model. In TgT(121) mice, cell-specific inactivation of the pRb pathway in brain choroid plexus epithelium initiates tumorigenesis and induces p53-dependent apoptosis. We previously showed that p53 deficiency accelerates tumor growth due to diminished apoptosis. Here we show that in a p53(+/-) background, slow-growing dysplastic tissue undergoes clonal progression to solid angiogenic tumors in all animals. p53 is inactivated in all progressed tumors, with loss of the wild-type allele occurring in 90% of tumors. Moreover, similar progression occurs in 38% of TgT(121)p53(+/+) mice, also with loss of at least one p53 allele and inactivation of p53. Thus, the selective pressure for p53 inactivation, likely based on its apoptotic function, is high. Yet, in all cases, p53 inactivation correlates with progression beyond apoptosis reduction, from dysplasia to solid vascularized tumors. Hence, p53 suppresses tumor progression in this tissue by multiple mechanisms. Previous studies of fibroblasts and hematopoietic cells show that p53 deficiency can be associated with chromosomal instability, a mechanism that may drive tumor progression. To determine whether genomic gains or losses are present in tumors that progress in the absence of p53, we performed comparative genomic hybridization analysis. Surprisingly, the only detectable chromosomal imbalance was partial or complete loss of chromosome 11, which harbors the p53 gene and is thus the selected event. Flow cytometry confirmed that the majority of tumor cells were diploid. These studies indicate that loss of p53 function is frequent under natural selective pressures and furthermore that p53 loss can facilitate epithelial tumor progression by a mechanism in addition to apoptosis reduction and distinct from chromosomal instability.

Animals↗

PubMed2001

Multipond system: a sustainable way to control diffuse phosphorus pollution.

Diffuse pollution from agricultural land is one of the main causes for lake eutrophication. Multipond systems, an ancient invention in China, are composed of many tiny ponds and ditches, scattered in agricultural fields. After a long period of research in an experimental watershed in Liuchahe, it was found that multipond systems constitute diffuse pollution control. They have a large capacity for water storage and serve to control the export of water, suspended matter, and phosphorus. Multipond systems significantly reduce runoff velocity. Sediments and phosphorus retained in the Liuchahe watershed were 14.38 x 10(6) and 7016 kg yr-1, respectively (area 691.6 ha). Irrigation provides an effective way to recycle and remove phosphorus. The use of multipond systems is a sustainable way to recycle valuable nutrients and reduce their discharge and thus pollution of downstream lakes.

Agriculture↗

PubMed2001

Effect of aloe-emodin on expression of proliferating cell nuclear antigen of vascular smooth muscle cells in culture after arterial injury.

OBJECTIVE: To observe the effect of aloe-emodin on the expression of proliferating cell nuclear antigen (PCNA) in smooth muscle cells (SMCs) after arterial injury and study the molecular mechanism of inhibition of aloe-emodin on SMC proliferation. METHODS: Deendothelialization was performed at the abdominal aorta in Japanese white rabbits using a 3F Fogarty arterial embolectomy catheter. 48 hours later, the medium of abdominal aorta was isolated and primary SMCs culture was performed. Cells were synchronized to G0 by serum starvation, then aloe-emodin at a concentration of 20 micrograms/ml was added to the culture medium containing 10% [v/v] fetal calf serum. Vehicle was also added to the medium as a control. After 18 hours, the expression of PCNA at the level of mRNA and protein were examined using techniques of RT/PCR, Western blotting and inmmunocytochemistry respectively. RESULTS: Compared with the control group, the expression of PCNA mRNA and protein was prominently decreased after addition of aloe-emodin. CONCLUSION: The inhibition of aloe-emodin on SMCs proliferation may be caused by inhibiting the expression of the PCNA gene.

Animals↗

PubMed2001

[Evaluation of treatment for retinal detachment in juveniles].

OBJECTIVE: To assess the effectiveness of different surgeries for retinal detachment in juveniles. METHODS: A retrospective analysis of the clinical therapeutic effects of various surgical treatments on 108 cases (116 eyes) in the age range of 3 - 14 years (mean, 9.6 years) was performed. RESULTS: Twenty-one eyes underwent scleral buckling procedure, and the retina was reattached in 19 eyes primarily. Fourteen eyes obtained post-operative visual acuity >or= 0.02. Ninety-seven eyes underwent vitrectomy, 58 (59.8%) eyes achieved retinal reattachment primarily and 83 eyes (85.6%) achieved retinal reattachment finally. Among them, retinal reattachment occurred in 7 of 11 gas-filled eyes, and the post-operative visual acuity >or= 0.02 in 5 eyes; and the reattachment occurred in 51 (57.3%) of 89 silicone oil-filled eyes, requiring only the primary repair. Of the silicone oil-filled eyes, 76 (85.4%) eyes achieved retinal reattachment finally. Fifty-nine (66.3%) silicone oil-treated eyes had visual acuity >or= 0.02 compared with 45.5% in long-acting-gas-treated eyes. CONCLUSIONS: Scleral buckling is a beneficial method in treatment of retinal detachment in juveniles. Vitrectomy should be considered for complicated retinal detachment. There is an advantage favoring silicone oil tamponade in achieving retinal reattachment. Retinotomy is a useful procedure for the retinal reattachment in eyes with severe proliferative vitreoretinopathy, however, it is necessary to be careful in selection of cases to undergo such a procedure.

Adolescent↗

PubMed2000

[Clinical analysis of 29 cases of hounglass spinal tumor].

We analysed retrospectively 29 cases with hounglass tumor in spinal canal from March 1990 to November 1998 in our hospital. Hounglass tumors in all patients were successfully diagnosed by CT scanning and magnetic resonance imaging(MRI). Microsurgery was carried out in 27 cases(27/29). Sixteen out of 27 cases were followed up from 8 months to 7 years. The result showed that 12 cases got complete healing, and 3 cases incomplete healing. The paper has stress discussion on the clinical features, CT, MRI examination and operation of the disease.

Adolescent↗

PubMed2000

Murine immune responses to mucosally delivered Salmonella expressing Lassa fever virus nucleoprotein.

Arenaviruses are emerging pathogens known to infect via the mucosa, however no formal attempts to make mucosal vaccines have been undertaken. Here we describe a recombinant aroA attenuated Salmonella typhimurium that expresses the nucleoprotein (NP) gene of Lassa fever virus (LAS). The complete NP gene was cloned downstream of the bacterial groEL promotor and integrated into the aroA locus of S. typhimurium. Lassa NP protein was detected in whole cell extracts from the recombinant Salmonella by immunoblot analysis with serum from Lassa-infected people. Mice were inoculated by intragastric intubation with 5 x 10(9) S. typhimurium and boosted with the same recombinant Salmonella 21 days after the primary inoculation. Both local mucosal IgA and serum immunoglobulins against Lassa NP were observed. Splenic cytotoxic T-lymphocyte responses to LAS NP were detected after the boost and they cross-reacted with target cells infected with the related arenavirus, lymphocytic choriomeningitis virus. Recombinant Salmonella elicits humoral and cell mediated immune responses against Lassa fever virus in mice and should be considered as a potential vaccine strategy in man.

Animals↗

PubMed2000

Surface integration influences depth discrimination.

Image fragments arising from partial occlusion may be perceptually unified by a surface integration process on the basis of similar color or texture. In a new objective measure pitting surface feature similarity against binocular disparity, observers discriminated whether a colored circle had either crossed or uncrossed disparity relative to a surrounding gray rectangle. Sensitivity to disparity was impaired only when (1) the configuration of the other surface fragments in the display supported the integration of a surface behind the rectangle and circle, and (2) matched the color of the central circle. Results were consistent with the hypothesis that a surface integration process integrated similarly-colored surface fragments into a smooth surface, even when those fragments were at different depths. Surface integration caused small and reliable effects on depth perception despite unambiguous disparity information. Perceived depth does not depend solely upon disparity, and may be determined after three-dimensional figural unity is established.

Color Perception↗

PubMed1999

Differences in mRNA expression patterns between patellar tendons and anterior cruciate ligaments of immature pigs.

The patellar tendon is the most commonly used graft source in reconstruction of the anterior cruciate ligament. The performance of a patellar tendon graft in such a reconstruction is largely related to the structural and functional differences between patellar tendons and anterior cruciate ligaments. From a genetic point of view, the structural and functional differences are ultimately decided by the differential patterns of gene expression between the two tissues. In the present study, the genetic differences between normal patellar tendons and normal anterior cruciate ligaments were explored by screening a large number of mRNA species to detect the species unique to each tissue. Of the approximately 1,000 mRNAs screened, 20 differentially expressed mRNA species were detected. Eight were unique to patellar tendons, and 12 were unique to anterior cruciate ligaments. Of these 20 unique mRNA species, 12 did not match any of the known sequences in gene databases and were probably novel genes. Transcriptional control is a major step in the genetic pathway; therefore, the variations found between patellar tendons and anterior cruciate ligaments at this level of gene expression indicate that the differences between the two tissues are likely more extensive than previously thought. These differences probably influence the survival of patellar tendon autografts and should be explored further.

Animals↗

PubMed1999

High major histocompatibility complex-unrestricted lysis of simian immunodeficiency virus envelope-expressing cells predisposes macaques to rapid AIDS progression.

Before the development of virus-specific immune responses, peripheral blood mononuclear cells (PBMC) from uninfected rhesus monkeys and human beings have the capacity to lyse target cells expressing simian immunodeficiency virus (SIV) or human immunodeficiency virus-1 (HIV) envelope (gp130 and gp120) antigens. Lysis by naive effector cells does not require major histocompatibility complex (MHC)-restricted antigen presentation, is equally effective for allogeneic and xenogeneic targets, and is designated MHC-unrestricted (UR) lysis. UR lysis is not sensitive to EGTA and does not require de novo RNA or protein synthesis. Several kinds of envelope-expressing targets, including cells that poorly express MHC class I antigens, can be lysed. CD4(+) effectors are responsible for most of the lytic activity. High lysis is correlated with high expression of HIV or SIV envelope, specifically, the central one-third of the gp130 molecule, and lysis is completely inhibited by a monoclonal antibody against envelope. Our work extends observations of human lymphocytes expressing HIV gp120 to the SIV/rhesus monkey model for AIDS. Additionally, we address the relevance of UR lysis in vivo. A survey of PBMC from 56 uninfected rhesus monkeys indicates that 59% of the individuals had peak UR lytic activity above 15% specific lysis. Eleven of these monkeys were subsequently infected with SIV. Animals with UR lytic activity above 15% specific lysis were predisposed to more rapid disease progression than animals with low UR lytic activity, suggesting a strong correlation between this form of innate immunity and disease progression to AIDS.

Animals↗

PubMed1999

Atm is dispensable for p53 apoptosis and tumor suppression triggered by cell cycle dysfunction.

Both p53 and ATM are checkpoint regulators with roles in genetic stabilization and cancer susceptibility. ATM appears to function in the same DNA damage checkpoint pathway as p53. However, ATM's role in p53-dependent apoptosis and tumor suppression in response to cell cycle dysregulation is unknown. In this study, we tested the role of murine ataxia telangiectasia protein (Atm) in a transgenic mouse brain tumor model in which p53-mediated apoptosis results in tumor suppression. These p53-mediated activities are induced by tissue-specific inactivation of pRb family proteins by a truncated simian virus 40 large T antigen in brain epithelium. We show that p53-dependent apoptosis, transactivation, and tumor suppression are unaffected by Atm deficiency, suggesting that signaling in the DNA damage pathway is distinct from that in the oncogene-induced pathway. In addition, we show that Atm deficiency has no overall effect on tumor growth and progression in this model.

Animals↗

PubMed1999

Dietary L-arginine attenuates expression of vascular cell adhesion molecule-1 in the aortae of hypercholesterolemic rats.

OBJECTIVE: To determine whether the antiatherogenic effect of L-arginine is due to an inhibition of vascular cell adhesion molecule-1 (VCAM-1) expression in the aortae of hypercholesterolemic rats. METHODS: Twenty-four male Wistar rats were randomized into three groups: Group NC with normal diet (NC, n = 8), Group CC with 4% cholesterol and 1% cholic acid diet (CC, n = 8), Group AC with 4% cholesterol and 1% cholic acid diet supplemented with 3% L-arginine HCl in the drinking water (AC, n = 8). Eight weeks later, the blood samples were collected for biochemical studies, and the aortae were harvested for RT-PCR and immunohistochemical studies. RESULTS: The results showed that dietary L-arginine supplementation reduced expression of VCAM-1 in protein level and mRNA level. CONCLUSION: Inhibitory effect of dietary supplementation of L-arginine on VCAM-1 expression may be one of the mechanisms of its antiatherosclerosis.

Animals↗

PubMed1998

Experimental study on the correlation of nitric oxide with portal hypertensive enteropathy.

To explore the role of nitric oxide (NO) in the pathogenesis of portal hypertensive enteropathy (PHE), cirrhotic portal hypertension was induced in Wistar rats by subcutaneous administration of carbon tetrachloride. At the end of 12th week, NADPH-diaphorase staining was performed on ice frozen sections with the sample of fresh colonic tissues. NO synthase (NOS) activities and NOS mRNA expression of colonic tissues were investigated with chemoluminescence method and reverse transcription-polymerase chain reaction (RT-PCR), respectively. After NADPH-diaphorase histochemical staining, the computer image analysis and paired t test showed that NOS staining intensities of submucosal vascular endothelial cells and nerve fibers were all significantly higher in PHE group than those in normal group (P < 0.01 and P < 0.05, respectively), but the intensities of superficial epithelial cells were significantly lower than those of controls (P < 0.01). Chemoluminescence method demonstrated that general NOS activity of colonic mucosa was significantly higher in PHE group than that in control group (P < 0.01). Moreover, the degree of iNOS activity increase was greater than that of cNOS (104% vs 35%). RT-PCR revealed that NOS mRNA expressions were dramatically higher in PHE group than those in control group (P < 0.01). The results suggested that NO, with its property of vasodilatation, may be involved in the pathogenesis of vascular lesions of PHE in cirrhotic rats, and may also has something to do with mucosal lesions of colon in PHE.

Animals↗

PubMed1998

Key roles for E2F1 in signaling p53-dependent apoptosis and in cell division within developing tumors.

Apoptosis induced by the p53 tumor suppressor can attenuate cancer growth in preclinical animal models. Inactivation of the pRb proteins in mouse brain epithelium by the T121 oncogene induces aberrant proliferation and p53-dependent apoptosis. p53 inactivation causes aggressive tumor growth due to an 85% reduction in apoptosis. Here, we show that E2F1 signals p53-dependent apoptosis since E2F1 deficiency causes an 80% apoptosis reduction. E2F1 acts upstream of p53 since transcriptional activation of p53 target genes is also impaired. Yet, E2F1 deficiency does not accelerate tumor growth. Unlike normal cells, tumor cell proliferation is impaired without E2F1, counterbalancing the effect of apoptosis reduction. These studies may explain the apparent paradox that E2F1 can act as both an oncogene and a tumor suppressor in experimental systems.

Animals↗