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Biomedical subjects

Q Fang

Publications and source records attributed to Q Fang.

At least 73 records · Page 4Linked to original sources
PubMed1997

Targeted disruption of the melanocortin-4 receptor results in obesity in mice.

The melanocortin-4 receptor (MC4-R) is a G protein-coupled, seven-transmembrane receptor expressed in the brain. Inactivation of this receptor by gene targeting results in mice that develop a maturity onset obesity syndrome associated with hyperphagia, hyperinsulinemia, and hyperglycemia. This syndrome recapitulates several of the characteristic features of the agouti obesity syndrome, which results from ectopic expression of agouti protein, a pigmentation factor normally expressed in the skin. Our data identify a novel signaling pathway in the mouse for body weight regulation and support a model in which the primary mechanism by which agouti induces obesity is chronic antagonism of the MC4-R.

Animals↗
PubMed1997

[Optimal high-yield agronomic measures for Curcuma longa L].

Regression method of orthogonal conic substitution with factors was employed to build up a tuber yield simulation model. Three main measures (sowing time, plant population, application rate of fertilizer) affecting the tuber yield were analyzed by the mathematical model of three unknown second order orthogonal rotative regression. The optimal agronomic measures were obtained. The results indicate that sowing time and plant population play a important role in raising the tuber yield. Sowing time is clearly interrelated with plant population, and likewise, plant population application rate of fertilizer.

Fertilizers↗
PubMed1997

[Effects of cigarette smoke extract on proliferation and ET-1 release of airway smooth muscle cells].

OBJECTIVE: To investigate whether the effect of smoking on airway smooth muscle cells (ASMC) is mediated by the autocrine action of endothelin-1 (ET-1). METHODS: Abbit ASMC was cultured exposed to cigarette smoke extract (CSE), we examined the mitogenic effect CSE on ASMC in vitro and whether the ETA receptor antagonist JKC-301 can inhibit this effect. RESULTS: The exposure of ASMC to 10% and 30% CSE resulted in obvious cytotoxity. The viability of ASMC was decreased, the lipid peroxides (MDA) formation was increased, and the release of lactate dehydrogenase (LDH) into supernatant was enhanced. 5% CSE significantly enhanced the cultured ASMC[3H]-thymidine (3H-TdR) incorporation by 59.9% (P < 0.01) over control. The ASMC proliferative response to 5% CSE was dose-dependently inhibited by JKC-301. Moreover, 5% CSE evoked time-dependent release of endogenous ET-1 from ASMC. CONCLUSION: These data demonstrate that 5% CSE mediates ASMC proliferation via release and autocrine mitogenic action ET-1.

Administration, Inhalation↗
PubMed1997

[The secretion and receptor gene of insulin-like growth factor-I quantitative expression in ovarian stroma in polycystic ovarian syndrome patients].

OBJECTIVE: To explore varying different degrees of the action of insulin-like growth factor-I (IGF-I) and its receptor gene quantitative expression in the ovarian stroma of women with obese and nonobese polycystic ovarian syndrome (PCOS). METHOD: The expression of IGF-I receptor gene in the ovarian stroma from 35 cases of PCOS (obese: 15 cases; nonobese: 20 cases) and 20 cases of control were quantitatively determined by reverse transcript polymerase chain reaction (RT-PCR) combined with beta(2) micro globlin (beta(2) MG) gene as inner-control to amplificate sychronously. The grey value ratio of them were determined. The PCR-amplified cDNA fragments were put in restriction analysis (DdeI). RESULTS: The expression of IGF-I receptor in PCOS ovary stroma was significantly greater than in the control group (P < 0.001). The nonobese group presents more enhancement than obese group in IGF-I receptor gene expression. The restrictive fragments were same between the PCOS and the control group. CONCLUSIONS: The expression of IGF-I receptor in PCOS ovarian stroma is abnormally excessive and the nonobese PCOS have more potential action of IGF-I system in ovary stroma.

Adult↗
PubMed1996

Differential central projections of vestibular afferents in pigeons.

The question of whether a differential distribution of vestibular afferent information to central nuclear neurons is present in pigeons was studied using neural tracer compounds. Discrete tracing of afferent fibers innervating the individual semicircular canal and otolith organs was produced by sectioning individual branches of the vestibular nerve that innervate the different receptor organs and applying crystals of horseradish peroxidase, or a horseradish peroxidase/cholera toxin mixture, or a biocytin compound for neuronal uptake and transport. Afferent fibers and their terminal distributions within the brainstem and cerebellum were visualized subsequently. Discrete areas in the pigeon central nervous system that receive primary vestibular input include the superior, dorsal lateral, ventral lateral, medial, descending, and tangential vestibular nuclei; the A and B groups; the intermediate, medial, and lateral cerebellar nuclei; and the nodulus, the uvula, and the paraflocculus. Generally, the vertical canal afferents projected heavily to medial regions in the superior and descending vestibular nuclei as well as the A group. Vertical canal projections to the medial and lateral vestibular nuclei were observed but were less prominent. Horizontal canal projections to the superior and descending vestibular nuclei were much more centrally located than those of the vertical canals. A more substantial projection to the medial and lateral vestibular nuclei was seen with horizontal canal afferents compared to vertical canal fibers. Afferents innervating the utricle and saccule terminated generally in the lateral regions of all vestibular nuclei in areas that were separate from the projections of the semicircular canals. In addition, utricular fibers projected to regions in the vestibular nuclei that overlapped with the horizontal semicircular canal terminal fields, whereas saccular afferents projected to regions that received vertical canal fiber terminations. Lagenar afferents projected throughout the cochlear nuclei, to the dorsolateral regions of the cerebellar nuclei, and to lateral regions of the superior, lateral, medial, and descending vestibular nuclei.

Animals↗
PubMed1996

[A study on cAMP and Ca-CaM of the epithelium in human normal and cataractous lenses].

OBJECTIVE: The study was designed to study the relationship between calcium-calmodulin (Ca-CaM) and cyclic adenosine monophosphate (cAMP) systems and their possible cataractogenic effects. METHODS: We measured cAMP, Ca and Ca-CaM in the epithelium of human normal and cataractous lenses by enzymic and radioimmunoassay methods. RESULTS: The levels of Ca-CaM in the epithelium of senile cataractous lens were higher, while of cAMP were lower than that in the normal lens. CONCLUSION: The results imply that the low level of cAMP might cause the high level of calcium in the lens which is possibly a cataractogenic factor. The dangerous role of calcium is amplified by the elevation of Ca-CaM.

Adolescent↗
PubMed1995

VH and VL gene usage by anti-beta-amyloid autoantibodies in Alzheimer's disease: detection of highly mutated V regions in both heavy and light chains.

In a previous study, four human IgM kappa monoclonal antibodies (mAbs) secreted by Epstein-Barr-virus-transformed B cell lines independently derived from the peripheral blood of a patient with Alzheimer's disease (AD) were found to react with a conformational epitope of beta-amyloid protein and to stain amyloid plaques in AD brain. Three of these mAbs were studied further. They did not react with an additional panel of antigens and autoantigens. By a competitive inhibition ELISA, the Kd was determined to be 5.7 x 10(-8) M. The VH and V kappa of these mAbs were sequenced at the cDNA level and found to be identical. The corresponding VH and V kappa germline counterpart genes hsigghvm148 and hsiggkvm148 were identified to be analogous to the previous reported VH3 germline gene humighvf1/dp53 and the V kappa IV germline gene hsigk18. DA1/4 and JH4b were used by the heavy chain and J kappa 4 was used by the light chain. Multiple nucleotide substitutions were seen in both VH and V kappa when their sequences were compared to the germline sequences. High replacement/silent ratios in the CDR regions of both VH and V kappa indicate positive-selective pressure. Of a total of 22 amino acid replacements in VH and V kappa, 12 were nonconservative replacements. Furthermore, 7 of these 12 resulted in charge changes. The monoreactivity, the moderately high affinity constant, the clonal expansion evident by identical VH and VL used by these B cells secreting antibodies of interest, and the excessive replacement mutations in both VH and VL segments lead to the conclusion that these antibodies have been generated due to an antigen-driven process.

Alzheimer Disease↗
PubMed1995

Detection of T cell receptors in early rheumatoid arthritis synovial tissue.

Synovial tissue is rarely available from patients with early synovitis, with the exception of synovial biopsies. However, T cell populations early in the development of synovitis may be enriched in antigen-specific cells and critical to disease pathogenesis. To investigate the T cell repertoire in early synovitis, we utilized a PCR protocol for detection of T cell receptor (TCR) transcripts present in small amounts of synovial tissue. To expand the substrate for PCR, preamplification of cDNA was performed with a 3' constant region primer plus either a mixture of variable region primers or random hexanucleotides. Utilizing this method improved the sensitivity of detection. This technique is applied here to the analysis of TCR transcripts in synovial biopsies from individuals with early rheumatoid arthritis (RA) and non-RA synovitis. TCR alpha-chain transcripts were detectable in 5/5 RA and 4/4 non-RA specimens evaluated, with beta-chain transcripts detected in 4/5 early RA and 4/4 non-RA specimens evaluated. Confirmation of transcripts by sequencing of cloned PCR products verified the specificity of amplification. The most frequently expressed TCR V region families in early RA synovitis were V alpha 11, V alpha 14, V alpha 28, V beta 7, V beta 9 and V beta 17. Several of these V regions have previously been implicated in studies of chronic RA synovitis. J alpha and J beta region usage was similar to that seen in chronic RA, and conserved N region motifs were apparent. We conclude that it is possible to detect TCR transcripts in small synovial biopsies from individuals with early arthritis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Clinical use of selective reduction in multifetal pregnancies].

Selective reduction under ultrasound guidance was carried out in 12 multifetal pregnancies with over 3 fetuses during 8 to 14 gestational weeks. It was performed transabdominally in 9 women but in other 3, tansvaginal approach was used. Ten women have already delivered 19 viable infants, but the remaining 2 aborted after amniotic rupture during the second trimester. Selective reduction is a safe, feasible method for management of multifetal pregnancies with over 3 fetuses.

Female↗
PubMed1995

The analysis of disparity evoked potentials by a new form of static random-dot stereograms.

PURPOSE: A new form of static random-dot stereograms free of monocular clues was designed as stimulus to elicit disparity evoked potentials. METHODS: Disparity evoked potentials were recorded in 40 stereo-normal subjects. The stimulator was a white-black static random-dot stereograms generated by a computer and had no monocular clues. Every subject was tested in disparity stimulus, zero disparity stimulus, monocular stimulus and wearing prism condition. RESULTS: A characteristic wide positive wave at about 250 ms was consistently recorded in disparity stimulus, which may be regarded as evidence of the presence of stereopsis. In contrast, recordings for zero disparity stimulus, monocular vision, stimulus and wearing prism condition all demonstrated a markedly difference from recording for disparity stimulus.

Adolescent↗
PubMed1994

Human rheumatoid factors with restrictive specificity for rabbit immunoglobulin G: auto- and multi-reactivity, diverse VH gene segment usage and preferential usage of V lambda IIIb.

To determine the molecular and functional properties of human rheumatoid factors (RF), we established stable hybridomas and Epstein-Barr virus-transformed B cell lines from the synovial fluid or peripheral blood of three patients with rheumatoid arthritis and one patient with systemic lupus erythematosus. 17 cell lines were obtained that produced high-titer immunoglobulin M (IgM) RF that reacted exclusively with rabbit but not human IgG or IgG of other mammalian species. Certain anti-rabbit IgG RF also had specificity for other mammalian antigens (Ag), including cytoskeletal proteins and intracellular proteins found in HeLa cells, as well as for Ag present in an extract prepared from the cell wall of group A streptococci. 13 of the 17 RF contained lambda-type light (L) chains, of which 12 were classified serologically as members of the lambda-L chain variable region (V lambda) subgroup, designated V lambda III. The heavy chain V region (VH) and V lambda sequences of nine of these IgM lambda RF were determined at the cDNA level. Five VH genes in three VH families were used by these antibodies (Ab), including VH1 (dp21/1-4b and dp10 [51p1]/hv1051), VH3 (dp38/3-15 and dp77/13-21), and VH4 (dp70/4-4b). The deduced V gene-encoded amino acid sequences of the lambda chains of these IgM lambda RF confirmed their serological classification as lambda III, and they were further classified as members of the relatively uncommon V lambda III subgroup, designated V lambda IIIb. Based on cDNA analyses, nine were the product of three different V lambda III b germline genes. Two such genes, designated hsiggll150 and hsiggll295, were cloned and sequenced from genomic DNA. Unique combinations of these VH and V lambda III b genes could be related to distinctive patterns of reactivity among the IgM lambda RF. Although the VH and V lambda regions of these Abs were expressed primarily as germline-encoded sequences, four of nine multireactive Abs had extensive V region mutation, indicative of an Ag-driven process. The finding that lambda IIIb L chains are preferentially found among anti-rabbit IgG RF, and that some of these Ab have specificity for other protein, cellular, and bacterial Ag, provides new insight into the pathogenesis of RA and related diseases.

Animals↗
PubMed1994

Immunotherapeutic strategies targeting rheumatoid synovial T-cell receptors by DNA inoculation.

Immunotherapy against autoreactive T-cell receptors (TCRs) has been reported to have promise in several animal models of autoimmune diseases. Facilitated DNA inoculation has many potential advantages as a modality for development of specific immune responses. Specifically, this technology is able to deliver exogenous antigens for processing via both the endogenous pathway, with subsequent presentation by class-I major histocompatibility (MHC) antigens, and the exogenous pathway, with subsequent presentation by class-II MHC antigens. This allows for induction of both arms of the cellular immune system. These cellular immune responses may be particularly important in targeting and controlling pathogenic cell populations. The application of this technology to the treatment of human autoimmune diseases depends on the availability of readily manipulated systems for the evaluation of specific interventions. Here we report the full length cloning and expression of TCRs from rheumatoid arthritis synovial tissue. These were developed by recombinant polymerase chain reaction, cloning and retroviral transduction into a TCR-alpha/beta-negative murine T-cell hybridoma. Reconstitution of CD3 expression was confirmed by flow cytometry. Similar constructs have been developed for TCR-based immunotherapy by facilitated inoculation of DNA intramuscularly. Preliminary analysis of immune responses in mice indicates that these constructs elicit anti-TCR responses. These studies indicate the ability to reconstitute expression of potentially autoreactive human TCRs in a model system wherein specific immune responses elicited against these TCRs by various immunogens can be evaluated.

Amino Acid Sequence↗