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Biomedical subjects

L Yang

Publications and source records attributed to L Yang.

At least 649 records · Page 36Linked to original sources
PubMed1995

[Mental status and personality of infertile women].

Mental status and personality were investigated in 130 infertile women from November 1992 to May 1993 in the infertility clinic of The Second Hospital of Hunan Medical University. Causes of their infertility attributed to female (n = 65), male (n = 53), unexplained infertility (n = 12). Fifty four fertile women were recruited as normal control. A women consulting questionnaire, Eysenck personality questionnaire (EPQ), symptom checklist-90 (SCL-90), self-rating anxiety scale (SAS) and Hamilton depressive scale (HDS) were used in this study. The result showed that any level of mental pressure were found in 83.8% of infertile women, and moderate and severe in 52%. In comparison with the control, the prevalence of psychiatric symptoms were significantly higher in infertile than fertile women (P < 0.01). Infertile women were more likely to suffer from severe depression and anxiety. Their mental status were more unstable than fertile women and correlated with their personality traits. Authors emphasized that not only the somatic treatment, but also the psychological consultation and mental support should be provided in the program of the infertility management.

Adult↗
PubMed1995

The measurement and application of TSH-IRMA levels among different age groups in areas with iodine deficiency disorders.

Using immunoradiometric TSH assay (TSH-IRMA) to measure whole blood TSH levels spotted onto filter paper, we compared TSH levels among different age groups (neonates, < 1 yr infants, schoolchildren aged 7 to 14 yrs, adults, pregnant women and reproductive-age women) in Guiyang, where iodine deficiency has long been a problem. The results showed: 1) The percentage of subjects with TSH levels equal to or greater than 5 mIU/L in the neonate group was 38.9% while the percentages in the other groups were 0-3.3% (P < 0.01); 2) The TSH levels of the neonates were inversely related to the urinary iodine values of their mothers (pregnant women). (r = -0.5, P < 0.01); 3) 97.6% of the inhabitants in Guiyang ingested salt with less than 20 mg/kg iodine. The results indicate that iodine deficiency remains a problem in Guiyang. Neonates are the only ideal population for monitoring iodine deficiency.

Adolescent↗
PubMed1995

[Detection of the apoptosis-suppressing oncoprotein bcl-2 in ameloblastomas].

The product of apoptosis-suppressing oncoprotein bcl-2 can block apoptosis and result in the development of tumors. In this study, the expression of bcl-2 was observed in 40 cases of ameloblastomas by immunohistochemical staining. The results showed that the epithelium and reduced enamel epithelium of the enamel organ, the odontoblasts, basal cells of odontogenic cysts, normal oral epithelium and 90% (36/40) of ameloblastomas were positive for bcl-2, indicating that the expression of bcl-2 in odontogenic epithelium may be related to the degree of differentiation and proliferation of cells, the overexpression of bcl-2 may be associated with the development of ameloblastoma.

Ameloblastoma↗
PubMed1995

Calcitonin gene-related peptide release in endotoxicosis may be mediated by prostaglandins.

Three cyclo-oxygenase inhibitors (ibuprofen, indomethacin, and high dose aspirin) and two inhibitors of thromboxane biosynthesis (imidazole and low dose aspirin) were used to evaluate the role of prostaglandins and thromboxane in the release of calcitonin gene-related peptide (CGRP) during endotoxicosis. Endotoxin (lipopolysaccharide B from Salmonella Enteritidis, 5 mg/kg, intravenously) was administered to rats lightly anesthetized with ether during injection. After 3 h, endotoxin significantly elevated plasma CGRP levels by 3-fold. Ibuprofen (50 mg/kg, subcutaneously), indomethacin (10 mg/kg, subcutaneously) and high dose aspirin (100 mg/kg, intraperitoneally (i.p.)), but not imidazole (30 mg/kg, i.p.) or low dose aspirin (15 mg/kg, i.p.), significantly blocked endotoxin-induced CGRP elevations, suggesting that a prostaglandin, but not thromboxane, served as a mediator of CGRP release during endotoxicosis. Because endotoxin-induced production of prostaglandins is greatly diminished in endotoxin-tolerant rats (following multiple exposures to low dose endotoxin), we tested whether endotoxin-induced CGRP release also becomes diminished in tolerant rats. Accumulation of plasma CGRP was greatly diminished in endotoxin-tolerant rats exposed to endotoxin (5 mg/kg, intravenously), consistent with a mediator role for prostaglandins in the CGRP release during endotoxicosis.

Animals↗
PubMed1995

cDNA cloning and sequencing of 54kDa fragment of the 75kDa readthrough protein gene from beet necrotic yellow vein virus.

With viral RNA extracted from purified beet necrotic yellow vein virus (BNYVV) isolated from Inner Mongolia, the first strand of cDNA encoding a 54kDa fragment of the 75kDa readthrough protein on the RNA2 was synthesized by reverse transcription. A double-strand cDNA fragment of 1.5 kb was obtained after 30 cycles of PCR amplification. The fragment was ligated into and mapped on pGEM-7Zf(+). The result of sequence analysis shows that the 54kDa readthrough domain is 1509 nucleotides (nt). Compared with F13 isolate, the fragment shares 94.97% identity in terms of nucleotides with 3 nt deletion and 96.42% identity of deduced amino acids.

Amino Acid Sequence↗
PubMed1995

The inductive effect of bone morphogenetic protein (BMP) on human periodontal fibroblast-like cells in vitro.

Bone morphogenetic protein (BMP) has the capability of 1) inducing bone formation in non-bone tissue such as muscle, 2) promoting proliferation and differentiation of human dental pulpal cells, and 3) inducing early formation of both osteodentin and regular tubular dentin. In addition, when BMP is implanted in periodontal defects, it stimulates regeneration of periodontal tissues. In the present study, we sought to explore the mechanisms by which BMP induces these effects, using immunohistochemical methods to investigate periodontal fibroblast-like cells in vitro. Cellular production of fibronectin, endogenous BMP and alkaline phosphatase were measured using image analysis of immunohistochemical reactivity. Periodontal fibroblast-like cells incubated with exogenous BMP showed decreased alkaline phosphatase activity, unchanged fibronectin production, but increased expression of endogenous BMP compared with control specimens incubated without BMP. These data suggest that regenerative as well as inductive effects of BMP on undifferentiated periodontal mesenchymal cells may be mediated through its ability to modulate cellular expression of these substances.

Alkaline Phosphatase↗
PubMed1995

Induction of reparative dentin formation in dogs by bovine bone morphogenetic protein bound to ceramic dentin.

Bone morphogenetic protein (BMP) refers to a group of bone-inducing growth factors used to enhance experimental osseous repair. Previous studies have indicated that BMP promotes the proliferation and differentiation of fibroblasts from human dental pulp both in vitro and in vivo. Furthermore, when BMP is used as a pulp capping agent, it has ability to induce the formation of both osteodentin and tubular dentin. In this study, we sought to explore whether or not BMP, complexed to ceramic dentin (BMP/CD), would constitute a more effective pulp capping agent than BMP alone. Experimental pulp exposures were created in dogs, and BMP/CD was placed on the surface of the exposed dental pulp. The inductive effect of such stimulation on reparative dentin formation was observed morphologically. Results showed that two weeks after exposure, some osteodentinal matrix was formed in the space surrounding the implanted BMP/CD particles while the remainder of the space was occupied by proliferating fibroblasts. At 4 weeks postoperatively, the dential bridge was complete. When ceramic dentin without BMP was used, there was minimal bone-like matrix formed even at 4 weeks postoperatively. These results suggest that the BMP/CD complex is effective as a stimulant of reparative dentin formation and shows potential as a therapeutically useful pulp-capping agent in a clinical setting.

Animals↗
PubMed1994

Regulation of interleukin (IL)-11 gene expression in IL-1 induced primate bone marrow stromal cells.

Interleukin (IL)-1 alpha treatment of a primate bone marrow stromal cell line, PU-34, transiently increased the steady state level of IL-11 mRNA. Nuclear run-on experiments showed that the transcription rate of the IL-11 gene was not affected appreciably by IL-1 alpha induction, but changes in the half-life of the IL-11 mRNA corresponded well with the changes in the steady state level of the IL-11 mRNA during the induction. Although transient transfection of PU-34 cells with IL-11 promoter constructs failed to respond to IL-1 alpha, a 10-base pair promoter region and JunD.AP-1 complex were found to be responsible for the basal level transcription of the IL-11 gene. The tyrosine kinase inhibitor genistein accelerated the degradation of the IL-11 mRNA without affecting the transcription rate of the IL-11 gene in IL-1 alpha stimulated cells. The insertion of DNA sequences corresponding to the 3'-untranslated region of the IL-11 gene into a rabbit beta-globin gene resulted in destabilization of the chimeric mRNA which failed to be induced by IL-1 alpha. Exogenous IL-11 expression generated from transient transfection with plasmid pCMV-IL-11, however, can be stabilized by IL-1 alpha. In contrast to the hypothesis that AUUUA motifs in the 3'-untranslated region are sufficient to regulate cytokine mRNA stability, our results suggest that IL-1 alpha induced stabilization of the IL-11 mRNA requires participation of RNA sequences from different regions of the IL-11 message.

Animals↗
PubMed1994

Evidence that rapamycin inhibits interleukin-12-induced proliferation of activated T lymphocytes.

Interleukin 12 is a heterodimeric cytokine involved in the regulation of natural killer cell and T lymphocyte responses. In previous studies, we found that IL-12 induces proliferation of T cells only after co-stimulation with lectin, alloantigen, or anti-CD3 antibody. The IL-2-mediated proliferation of long-term T cell lines generated in this fashion is typically insensitive to the immunosuppressive agent, cyclosporine but sensitive to rapamycin. In this study, we examined the effect of cyclosporine and rapamycin on T cells responsive to IL-12. For long-term cultured T cell lines stimulated with phytohemagglutinin, alloantigen, or solid-phase anti-CD3 antibody, rapamycin blocked IL-12-induced proliferation to background levels. Culture in cyclosporine produced minimal inhibition of IL-12-induced T cell proliferation. Freshly isolated CD3+ cells did not proliferate in response to IL-12, nor did culture of these cells in IL-12 lead to upregulation of IL-2 receptor. These data suggest that the effect of IL-12, an important growth regulator for activated T lymphocytes, may involve late cellular activation events.

Antibodies↗
PubMed1994

The cellular DNA polymerase alpha-primase is required for papillomavirus DNA replication and associates with the viral E1 helicase.

Persistent infection by papillomaviruses involves the maintenance of viral DNA as a nuclear plasmid, the replication of which requires host DNA polymerases. The role of the cellular DNA polymerase alpha-primase holoenzyme was probed by using soluble extracts from rodent cells that replicate bovine papilloma virus 1 and human papilloma virus 6b DNA in the presence of the viral E1 helicase and the E2 transcription factor. Monoclonal antibodies directed against the catalytic 180-kDa subunit of polymerase alpha inhibit DNA synthesis in this system. Addition of purified human polymerase alpha-primase holoenzyme to neutralized extracts restores their DNA synthetic activity. The amino-terminal 424 amino acids of E1 forms a specific protein complex with the p180 polymerase subunit. Immune complexes can be isolated with antibodies directed against E1 that contain a DNA polymerase activity. Moreover, this polymerase activity can be neutralized by anti-polymerase alpha antibodies. Permissivity barriers were not encountered in this in vitro system, as bovine E1 can interface with the murine and human replication apparatus. Although the large tumor antigens encoded by simian virus 40 and polyoma share limited primary sequence homology with the papillomavirus E1 proteins, the organization of functional motifs at the level of primary protein structure is remarkably similar. In addition to their origin-specific DNA-binding activity, each of these helicases may function to help recruit the cellular polymerase alpha-primase complex to the viral replication origin.

Animals↗
PubMed1994

Beta 2-microglobulin-independent MHC class Ib molecule expressed by human intestinal epithelium.

A major histocompatibility complex class Ib protein, CD1d, is expressed by human intestinal epithelial cells (IECs) and is a ligand for CD8+ T cells. CD1d was found to be expressed on the surface of human IECs as a 37-kilodalton protein that was beta 2-microglobulin (beta 2M) independent with no N-linked carbohydrate. Transfection into a beta 2M- cell line confirmed that CD1d could be expressed at the cell surface in the absence of beta 2M. These data indicate that IECs use a specialized pathway for CD1d synthesis and that a beta 2M-independent class Ib protein may be the normal ligand for some intestinal T cells.

Antigens, CD↗
PubMed1994

Identification of cDNAs encoding bovine cyclin B and Cdk1/Cdc2.

cDNA sequences encoding homologs of cyclin B and Cdk1/Cdc2 were isolated from bovine blastocyst-stage embryos produced in vitro. The bovine CycB sequence is 1548 nucleotides (nt) in length and contains the conserved motif 'FLRRXSK', characteristic for known cyclin B proteins. The deduced protein contains 427 amino acids (aa) and has an estimated mass of 47,653 Da. The bovine cdk1/cdc2 sequence is 1275 nt in length and contains the highly conserved motif 'EGVPSTAIREISLLKE'. The deduced protein contains 297 aa (33,931 Da).

Amino Acid Sequence↗
PubMed1994

Fabrication and characterization of low-loss, sol-gel planar waveguides.

Applications of planar integrated optical waveguide (IOW) technology to problems in surface spectroscopy and optical chemical sensing have been partly limited by the difficulty of producing high-quality glass IOWs. The fabrication of IOWs by the sol-gel method from methyltriethoxysilane and titanium tetrabutoxide precursors is described here. The physical, chemical, and optical properties of the films during and after high-temperature annealing were studied using a variety of analytical techniques. The results show that the catalyst used to accelerate the sol-gel reaction strongly influenced the optical quality of the IOW. HCl catalysis produced waveguides with propagation losses of approximately 1 dB/cm, whereas in the case of SiCl4 catalysis, propagation losses were < 0.2 dB/cm, a value significantly less than any previously reported for sol-gel-derived IOWs. An examination of film surface structure and morphology by scanning electron microscopy and atomic force microscopy showed that the SiCl4-catalyzed IOWs were significantly smoother and more homogeneous on a submicrometer scale than the HCl-catalyzed IOWs. The use of SiCl4 is thought to retard formation of a microheterogeneous network containing Si-rich and Ti-rich domains, which is favored with HCl catalysis and contributes to the higher observed losses.

Fiber Optic Technology↗
PubMed1994

G protein coupling to the thrombin receptor in Chinese hamster lung fibroblasts.

The specific involvement of G proteins in thrombin receptor-mediated Ca2+ mobilization and DNA synthesis has been studied in single Chinese hamster lung fibroblasts (CCL39 cells) activated by the hexapeptide SFLLRN. Immunoblots performed with antibodies directed against the COOH terminus of G protein alpha subunits revealed that alpha q, alpha i, and alpha o were each present in CCL39 cells. The Ca2+ response to SFLLRN was measured after microinjection of anti-alpha q or anti-alpha o antibodies, which produced a total blockade in 71 and 46% of cells, respectively. A partial inhibition of the SFLLRN-induced Ca2+ response was observed in the remaining cells. The lag time between exposure of the cells to SFLLRN and the onset of Ca2+ mobilization was significantly longer (20-24 s) in cells microinjected with anti-alpha q- or anti-alpha o-antibodies than in control cells microinjected with preimmune serum (9 +/- 1 s). Moreover, the peak height of the Ca2+ response to SFLLRN was decreased by 36 and 73%, respectively in cells microinjected with anti-alpha q or anti-alpha o antibodies. SFLLRN-induced DNA synthesis in growth-arrested CCL39 cells was also inhibited (44-78%) by prior microinjection of anti-alpha q or anti-alpha o antibodies. Anti-alpha 1 antibodies had no effect on the SFLLRN-induced Ca2+ response or on DNA synthesis. These results provide direct evidence that the thrombin receptor in CCL39 cells is coupled to two different types of G proteins, Gq and Go, both causing Ca2+ mobilization and mitogenesis.

Amino Acid Sequence↗
PubMed1994

Inhibition of germinal vesicle breakdown in bovine oocytes by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB).

5,6-Dichloro-1-beta-D-ribofuranosyl-benzimidazole (DRB) is an analog of the nucleoside adenosine that has been used to inhibit transcription in a variety of cell types. The present studies were designed to evaluate the ability of DRB to block germinal vesicle breakdown (GVBD) in bovine oocytes matured in vitro and to characterize culture conditions required for DRB-mediated arrest of meiosis. Administration of DRB (60-90 microM) at 2-3 h intervals during culture of COC blocked GVBD in approximately 70 percent of oocytes. The inhibitory effect of DRB was reversible and required the presence of cumulus cells. Treatment with DRB was associated with a 57% decrease in 3H-uridine incorporation into total COC RNA and a 90.8% decrease into mRNA but did not affect the incorporation of 3H-leucine into COC proteins. The ability of DRB to arrest meiosis was significantly compromised if supplemental gonadotropin preparations were absent from the maturation media. Gonadotropin-induced GVBD as well as cumulus cell expansion was blocked by treatment with DRB but not with adenosine. GVBD in cultured bovine COC was initially inhibited and then stimulated when supplemental gonadotropin preparations were included in the culture media. DRB treatment in the presence of gonadotropin supplementation blocked the stimulatory effect of gonadotropins on GVBD. In conclusion, DRB can be used to arrest GVBD in bovine COC in a specific and reversible manner. The data support the hypothesis that gene transcription is required for the stimulatory phase of gonadotropin-mediated GVBD in cultured bovine COC.

Animals↗
PubMed1994

Release of [3H]5-hydroxytryptamine from the intermediate area of rat thoracic spinal cord is modulated by presynaptic autoreceptors.

Serotonin (5-HT) nerve terminals innervate sympathetic preganglionic neurons of the intermediolateral cell column (IML); however, neither the depolarization-induced release of 5-HT nor the presence of presynaptic modulatory autoreceptors have been directly studied in this system. We used in vitro superfusion of the microdissected intermediate area (including the intermediolateral cell column, intercalated nucleus, and central autonomic nucleus) of the rat thoracic spinal cord to measure basal and stimulated release of preloaded [3H]5-HT. Elevated K+ evoked a concentration- and Ca(2+)-dependent release of [3H]5-HT. Exogenous 5-HT and the 5-HT1B agonist, CGS-12066B, both decreased the K(+)-stimulated release of [3H]5-HT. A 5-HT1B antagonist (methiothepin) blocked the 5-HT- and the CGS-12066B-induced inhibition of K(+)-evoked release of [3H]5-HT. A 5-HT1A antagonist (NAN-190) did not alter the inhibitory actions of exogenous 5-HT. Moreover, a 5-HT1A agonist (8-OH-DPAT), a 5-HT2A/2C agonist [(+/-)-DOI hydrochloride), and a 5-HT3 agonist (2-methyl-5-HT) did not alter the K(+)-evoked release of [3H]5-HT. These data demonstrate that 5-HT is released from the intermediate area of the rat thoracic spinal cord. The 5-HT receptor subtype involved in the inhibition of the evoked release of [3H]5-HT is of the 5-HT1B subtype. These findings may help clarify the complex role of 5-HT in spinal regulation of the sympathetic nervous system.

Animals↗