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Biomedical subjects

Y Ying

Publications and source records attributed to Y Ying.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effects of male accessory sex glands on deoxyribonucleic acid synthesis in the first cell cycle of golden hamster embryos.

To study the paternal effect, particularly of accessory sex gland secretions, on DNA synthesis in golden hamster zygotes, the glands were surgically removed from golden hamsters resulting in 4 groups: SH, sham-operated; AGX, bilateral excision of ampullary glands; VPX, bilateral excision of ventral prostates; and TX, excision of all accessory sex glands. Each female was mated with one male and killed at 6, 8, 10, or 12 h postcoitus (p.c.). Embryos were collected, and zygotes in S-phase were identified by immunocytochemical techniques after pulse-labeling with 50 microM 5-bromo-2'-deoxyuridine-5'-monophosphate (BrdU) in Tyrode's albumin lactate pyruvate medium for 30 min. In another experiment, embryos at 6 h p.c. were incubated in 50 microM BrdU for 6 h. Presumptive zygotes were stained with propidium iodide to visualize pronuclei. The BrdU pulse-labeling results showed that the percentages of embryos with 1 or 2 pronuclei in S-phase at 8 h p.c. in VPX (44.3 +/- 10.4) and TX (41.6 +/- 10.6) groups were significantly lower (p < 0.05) than that in the SH group (69.0 +/- 5.5). In the AGX group, although the percentage of embryos with 1 or 2 pronuclei in S-phase was not significantly different from that of the SH group, the percentage of 8-h embryos with 2 pronuclei in S-phase was 51.6 +/- 2.8, significantly lower than in the SH control (68.1 +/- 6.0, p < 0.05). When the embryos were labeled with BrdU for 6 h, the percentages of embryos with 1 or 2 pronuclei in S-phase were not different among the 4 groups. However, the percentage of embryos showing 2 pronuclei in S-phase was significantly lower in the AGX group (78.4 +/- 6.7) than in the SH group (91.8 +/- 2.9, p < 0.05). These results suggest that accessory sex glands can affect DNA synthesis in hamster zygotes and that the mechanisms by which ampullary gland and ventral prostrate secretions affect the first cell cycle are probably different. A significantly higher incidence (p < 0.001) of polyspermy was observed in embryos sired by males without ampullary glands (5.2 +/- 1.0%) compared with those sired by the SH group (0.8 +/- 0.3%).

Animals↗
PubMed1997

Platelet-derived growth factor activates mitogen-activated protein kinase in isolated caveolae.

The ability of a peptide hormone to affect many different intracellular targets is thought to be possible because of the modular organization of signal transducing molecules in the cell. Evidence for the presence of signaling modules in metazoan cells, however, is incomplete. Herein we show, with morphology and cell fractionation, that all the components of a mitogen-activated protein kinase pathway are concentrated in caveolae of unstimulated human fibroblasts. Addition of platelet-derived growth factor to either the intact cell or caveolae isolated from these cells stimulates tyrosine phosphorylation and activates mitogen-activated protein kinases in caveolae. The molecular machinery for kinase activation, therefore, is preorganized at the cell surface of quiescent cells.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1997

Tyrosine kinase receptors concentrated in caveolae-like domains from neuronal plasma membrane.

Recent evidence suggests that tyrosine kinases are highly organized in caveolae of tissue culture cells. We now report the isolation of a membrane domain from neuronal plasma membranes that has the biochemical characteristics of caveolae. A low density membrane (LDM) fraction with the same density as caveolae was highly enriched in tyrosine kinases such as insulin receptors, neurotrophin receptors, Eph family receptors, and Fyn. Grb2, Ras, heterotrimeric GTP-binding proteins, and Erk2 were also concentrated in the LDM. Incubation of the LDM fraction at 37 degrees C stimulated the phosphorylation on tyrosine of multiple, resident proteins, whereas the bulk membrane fraction was devoid of tyrosine kinase activity. The LDM, which makes up approximately 5-10% of the plasma membrane protein, appears to be organized for signal transduction.

Animals↗
PubMed1997

[The development of an computerized analysis system for the women pelvic cavity impedance rheogram].

This article introduces the components and functions of an computered analysis system for the women pelvic cavity impedance rheogram. It can sample the pelvic cavity impedance rheogram signal of the body double-side and the reference ECG signal. With help of manual intervence, it also can automatically recognize characteristic points of the pelvic cavity impedance rheogram and measure the parameters. It can correct the recognized characteristic points simultaneously and print the pelvic cavity impedance rheogram of the body double-side and 15 characteristic data parameters. After clinical applying, the analysis results of mors 100 patients make clear that: this system has remarkably clinical significance for diagnosis of the women pelvic cavity extravasated blood and evaluation of treating effect, so it has much better clinical applied expectation.

Equipment Design↗
PubMed1996

Localization of platelet-derived growth factor-stimulated phosphorylation cascade to caveolae.

Previously we showed that interleukin 1 beta stimulates the conversion of sphingomyelin to ceramide in the caveolae fraction of normal human fibroblasts. The ceramide, in turn, blocked platelet-derived growth factor (PDGF) stimulated DNA synthesis. We now present evidence that the PDGF receptor initiates signal transduction from caveolae. Cell fractionation and immunocytochemistry show caveolae to be the principal location of PDGF receptors at the cell surface. Multiple caveolae proteins acquire phosphotyrosine when PDGF binds to its receptor, but the hormone appears to have little effect on the tyrosine phosphorylation of non-caveolae membrane proteins. Five proteins known to interact with the phosphorylated receptor were found to be highly enriched in caveolae membrane. PDGF caused the concentration of three of these proteins to significantly increase in the caveolae fraction. Finally, PDGF stimulated the association of a 190-kDa phosphoprotein with the caveolae marker protein, caveolin. Therefore, ceramide may modulate PDGF receptor function directly in caveolae.

Caveolin 1↗
PubMed1996

Acylation targets emdothelial nitric-oxide synthase to plasmalemmal caveolae.

Endothelial nitric-oxide synthase (eNOS) generates the key signaling molecule nitric oxide in response to intralumenal hormonal and mechanical stimuli. We designed studies to determine whether eNOS is localized to plasmalemmal microdomains implicated in signal transduction called caveolae. Using immunoblot analysis, eNOS protein was detected in caveolar membrane fractions isolated from endothelial cell plasma membranes by a newly developed detergent-free method; eNOS protein was not found in noneaveolar plasma membrane. Similarly, NOS enzymatic activity was 9.4-fold enriched in caveolar membrane versus whole plasma membrane, whereas it was undetectable in non-caveolar plasma membrane. 51-86% of total NOS activity in postnuclear supernatant was recovered in plasma membrane, and 57-100% of activity in plasma membrane was recovered in caveolae. Immunoelectron microscopy showed that eNOS heavily decorated endothelial caveolae, whereas coated pits and smooth plasma membrane were devoid of gold particles. Furthermore, eNOS was targeted to caveolae in COS-7 cells transfected with wild-type eNOS cDNA. Studies with eNOS mutants revealed that both myristoylation and palmitoylation are required to target the enzyme to caveolae and that each acylation process enhances targeting by 10-fold. Thus, acylation targets eNOS to plasmalemmal caveolae. Localization to this microdomain is likely to optimize eNOS activation and the extracellular release of nitric oxide.

Acylation↗
PubMed1996

Biological effects of weak blast waves and safety limits for internal organ injury in the human body.

One hundred and seventeen adult sheep of both sexes, each weighing 15.2-42.4 kg, were used for this study. The purpose of this study was to investigate the relationship of the physical parameters of the waves to internal organ injury by exposing sheep to weak blast waves in TNT (trinitrotoluene) explosions, biological shock tube, and gun muzzle blasts. The results showed that the organ most sensitive to the TNT explosion was the lungs, whereas the upper respiratory tract was most sensitive to muzzle blast waves. The injury thresholds of overpressure were 29.0, 29.5, and 41.2 kPa for upper respiratory tract, lungs, and gastrointestinal tract respectively at a single exposure. Repeated exposure to 60 blasts reduced the injury threshold of the internal organs. The injury thresholds for upper respiratory tract, lungs, and gastrointestinal tract were 21.0, 18.0, and 40.4 kPa, respectively. The duration of overpressure of weak blast waves was 2.4-4.2 milliseconds, which did not significantly affect the severity of injury. The safety limits of weak blast waves to internal organ injury of human body were as follows: Ps = 37-3Ln.Tc.N/4(Tc.N < or = 1000) and Ps = 20.4(Tc.N > 1000). The results suggest that repeated exposures decrease the injury threshold of the internal organs. The safety limits proposed could protect 90% of the exposed population against internal organ injury caused by weak blast waves.

Animals↗
PubMed1996

[Effects of blastocyst deficiencies induced by aspirin treatment during preimplantation period in rats on development of embryos after implantation].

Pregnant rats were treated orally with aspirin 0.5 or 1.0 g.kg-1 on d 3 (positive vaginal smear was considered as d 0) and were sacrificed on d 4. Some blastocysts collected on d 4 were evaluated for gross morphology and cell number, and the remainings were transfered into pseudopregnant rats. Results showed that the rate of blastocysts with abnormal morphology were 23.8% and 40.8%, respectively, in 0.5 and 1.0 g.kg-1 of aspirin. These were significantly higher than 6.8% of the control group. The cell number of blastocysts also decreased in the aspirin groups. The rate of implantation and live fetuses in the case of blastocysts with normal morphology were related negatively with the aspirin doses, espesially in the group of 1.0 g.kg-1 of aspirin, the implantation rate was significantly lower (38.6%). However, the implantation rate of blastocysts with abnormal morphology in both groups of aspirin were much less than that of the control group, and all embryos after implantation were resorped. No significant malformations were observed in the live fetuses. These results suggests that the effects of blastocyst deficiencies induced by aspirin on development of embryos transfered into pseudopregnant rats mainly caused death of embryos, but not malformation of fetuses.

Animals↗
PubMed1995

[Pharmacokinetics of contragestazol (DL-111-IT), a new non-steroid antifertility agent in monkeys].

The pharmacokinetics of contragestazol, an early pregnancy temperating agent [3-(2-ethylphenyl)-5-(3-methoxyphenyl)-1H-1,2,4-triazole, DL-111-IT] was studied in Rhesus monkey. The blood concentration of DL-111-IT was determined by coupled column system HPLC method. Using an aqueous vehicle (20% cremophor EL in saline) DL-111-IT was injected intravenously to monkeys at doses of 25, 12.5 and 6.3 mg.kg-1. Blood drug concentration were measured. Using a programmable calculator the calculated pharmacokinetic parameters were as follows: alpha 1.83 h-1, 4.71 h-1 and 3.61 h-1, beta 0.15 h-1, 0.08 h-1 and 0.09 h-1; T1/2 beta 6.63 h, 10.2 h and 10.1 h; AUC 9.54 micrograms.h-1.ml-1, 3.94 micrograms.h-1.ml-1 and 3.75 micrograms.h-1.ml-1. An oil solution of DL-111-IT was injected intramuscularly in monkeys at doses of 50, 25 and 12.5 mg.kg-1. Its blood concentrations were determined at 0.08, 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 8, 12 and 24 h after administration. From the time vs concentration curve, the pharmacokinetic parameters obtained were as follows: Ka 0.98 h-1, 1.03 h-1 and 1.45 h-1; Ke 0.42 h-1, 0.37 h-1 and 0.60 h-1; T1/2Ke 1.66 h, 1.90 h and 1.16 h; T (peak) 1.52 h, 1.57 h and 1.09 h; AUC 4.86 micrograms.h-1.ml-1, 5.61 micrograms.h-1.ml-1 and 1.74 micrograms.h-1.ml-1.

Abortifacient Agents, Nonsteroidal↗
PubMed1994

Mechanism of cigarette smoke condensate induced adhesion of human monocytes to cultured endothelial cells.

Cigarette smoking is ranked among the leading risk factors in the etiology of atherosclerotic vascular disease. The mechanisms, however, that link cigarette smoking to increased incidence of atherosclerosis are not understood. The adherence of circulating monocytes to the endothelium, migration into the subendothelium, and subsequent formation of foam cells are principal initial events in the development of atherosclerosis. We therefore determined whether cigarette smoke caused increased adherence of monocytes to endothelial cells and the cellular mechanism of this increased adherence. Cigarette smoke condensate (CSC), the particulate fraction of cigarette smoke derived from 2R1 standard research cigarettes, at a concentration of 25-30 micrograms/ml (average yield of CSC is 26.1 mg/cigarette), augmented (70-90%) basal adherence of human peripheral blood monocytes to a cultured monolayer of endothelial cells derived from bovine aorta (BAEC) and human umbilical vein (HUVEC). There was a concomitant increase in the expression of CD11b ligand on the surface of monocytes as determined by flow cytometry, utilizing FITC conjugated Mab MO-1 (CD11b). However, nicotine (1-15 micrograms/ml) and cadmium sulfate (10 micrograms/ml), constituents of CSC, individually or in combination had no effect either on CD11b expression or adherence of monocytes to endothelial cells. Treatment of HUVEC with CSC for 60 min also resulted in an increased expression of ICAM-1 and ELAM-1 as determined by mean fluorescence intensity of ICAM-1 and ELAM-1 labeled cells in flow cytometric analysis. The CSC induced expression of CD11b in monocytes was optimal at 25-30 min and was inhibited by protein kinase C inhibitors, staurosporine and H-7, and also by baicalein, a lipoxygenase inhibitor. Similarly, CSC induced ICAM-1 and ELAM-1 expression in HUVEC was inhibited by protein kinase C inhibitors. CSC stimulated the adherence of human monocytes but not the monocytic cell lines HL-60, U937, and THP-1 to endothelial cells. The CSC stimulated adherence of human monocytes was inhibited (80%) by MAb to CD11b and 50% by Mab to ICAM-1 and ELAM-1. These results suggest that cigarette smoke particulate constituents activate protein kinase C, leading to increased surface expression of adhesive ligand CD11b on peripheral blood monocytes and counter receptor(s) ICAM-1 and ELAM-1 in endothelial cells. The expression of ligand and counter receptor leads to potentiated adherence of monocytes to endothelial cells, an initial event in the pathogenesis of cigarette smoke induced inflammatory response in the vessel wall.

Alkaloids↗
PubMed1994

[Study on the nootropic mechanism of ginsenoside Rb1 and Rg1--influence on mouse brain development].

Weaning mice were supplied drinking water containing Rb1 or Rg1 0.125 or 0.25 mg.ml-1 for 4 weeks. Rb1 (28.6 and 56.1 mg.kg-1) and Rg1 (27.4 and 53.9 mg.kg-1) were found to accelerate young mice body and brain development as well as facilitate memory acquisition in step down and step through avoidance response tests. With the technique of quantitative measurement synapses, we found for the first time that Rb1 and Rg1 administration for 4 weeks can increase synapse number in the hippocampal CA3 region of mice. This is the morphological basis for explaining Rb1 and Rg1 induced facilitation of learning and memory.

Animals↗
PubMed1993

The frequency of immortalization of human fibroblasts and mammary epithelial cells transfected with SV40 large T-antigen.

SV40 T-antigen-expressing human cells generally have an extension of lifespan until a period called "crisis" begins. On rare occasions a clone of cells emerges from the population in crisis and gives rise to an immortalized cell line. The present study compares the frequency of immortalization of cells from two different human lineages, lung fibroblasts and mammary epithelial cells. Most of the T-antigen-transfected clones from both cell types failed to immortalize, however, within those clones which were immortalization-competent the frequency of escape from crisis was found to be much higher (10(-5)) in mammary epithelial cells than in human fibroblasts (3 x 10(-7)). The frequency of escape from crisis in fibroblasts could be increased by chemical mutagenesis or by infection with a defective retrovirus. T-antigen-transfected fibroblasts were uniformly highly aneuploid both before and after crisis. In contrast, many SV40 T-antigen- and human papilloma virus 16 E6- or E6/E7-transfected mammary epithelial clones maintained a subpopulation of pseudodiploid cells prior to crisis, and the immortal cells that emerged following crisis were generally pseudodiploid. The higher frequency of escape from crisis in mammary epithelial cells is best explained by postulating a mutational inactivation of one allele of a critical gene followed by the elimination of the remaining wild-type alleles, with a much higher frequency of this second event in mammary epithelial cells due to their reduced ploidy compared to that in T-antigen-transfected fibroblasts. The results are discussed in terms of the regulation of telomerase activity and the M1/M2 model of cellular senescence.

Antigens, Polyomavirus Transforming↗
PubMed1993

The effect of sperm preparation methods on the fertilization rate of oocytes micro-inseminated by subzonal sperm injection.

Three methods were used to prepare spermatozoa for subzonal injection into mature oocytes. In method A, the washed sperm suspension was incubated for 18 h in modified T6 culture medium. Method B consisted of incubating the sperm suspension for 6 h in regular T6 culture medium. In method C, the sperm suspension was incubated for 6 h in regular T6 culture medium containing 20% (v/v) follicular fluid. The percentages of acrosome-free spermatozoa and fertilization rates were compared for 42 treatment cycles assigned randomly to the three sperm preparation methods. The sperm suspensions prepared by methods A and C each had significantly higher proportions of acrosome-free spermatozoa compared to suspensions prepared by method B. The fertilization rates of oocytes micro-injected with spermatozoa prepared by methods A and C were significantly higher than for method B. Eight clinical pregnancies resulted from 28 cycles in which embryo replacement occurred. We conclude that the fertilization rate following subzonal sperm injection is related directly to the percentage of acrosome-free spermatozoa in the sperm suspension used for microinjection.

Embryo Transfer↗
PubMed1993

[Effects of preimplantation treatment with aspirin and acetaminophen on blastocyst and fetus in rats].

Pregnant rats were treated with ig aspirin (Asp) and acetaminophen (Ace) on d 3 of pregnancy (positive vaginal smear = d 0). Blastocysts were collected on d 4 and evaluated for gross morphology, cell number, micronucleus, and mitotic index. Some rats were killed on d 20 and fetuses were examined for teratogenic effects. On d 4 a reduction of cell number per blastocyst was found in the rats treated with Asp 0.5, 1 g.kg-1, and Ace 1 g.kg-1, while the mitotic index, frequency of micronuclei, and frequency of blastocysts with morphological alterations were increased. The frequency of micronuclei was increased in rats exposed to Ace 0.25 and 0.5 g.kg-1. On d 20 major malformation and embryotoxicity were seen in Asp 0.5, 1, and Ace 1 g.kg-1 groups.

Acetaminophen↗
PubMed1993

[Comparison of bronchodilator effects and site of action of fenoterol and ipratropium in chronic obstructive bronchitis].

There is no lack of data in the literature reporting on the efficacy of different bronchodilators. However, the discussion concerning the superiority of one bronchodilator over another in patients with chronic bronchitis and airflow obstruction is, and remains, a controversial subject. This has been particularly so since the perfection of synthetic anticholinergics delivered by inhalation without any side-effects. The aim of the present work is to compare the bronchodilator effects of a sympathomimetic, fenoterol (Berotec), and of an anticholinergic, ipratropium bromide (Atrovent), compared to a placebo in twelve unselected chronic bronchitics who had airflow obstruction and were in a stable clinical state. The bronchodilator effect of the two drugs was judged at the same time by variations on forced expired volume (FEV1) which was taken as a reference value, and of the maximum mid-expiratory flow (MEF) measured by spirography and also the variations of pulmonary resistance (delta Rrs) measured by the forced oscillatory method. The comparison of these indices enables the site of action of these agents to be specified. The dose response curve and the duration of action over six hours was assessed for each of the three agents. These were administered in succession and at random over three days by inhalation using an inhalation chamber. All the patients who were included were capable of producing a bronchodilator response but two of them responded only to one agent. The change in the FEV1 was comparable with the two active products. The change in MEF (an index of peripheral airways) was significantly greater following ipratropium.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1992

Within-breath variations of forced oscillation resistance in healthy subjects.

Respiratory resistance (Rrs) was measured by the forced oscillation technique at 10, 20 and 30 Hz in 54 healthy subjects. The sinusoidal pressure oscillations were applied around the head, rather than at the mouth, so as to minimize transmural pressure across extrathoracic airway walls and the corresponding artefact (Peslin et al., J Appl Physiol, 1985, 59, 1790-1795). The flow (V') and volume (V) dependences of Rrs during the respiratory cycle were analysed by least square regression according to: Rrs = K1 + 2.K2.[V']#- K3.V, where K1 and K2 are Rohrer's constants, and where K3 expresses the (negative) volume dependence of Rrs. The analysis was made separately on the inspiratory and expiratory phases. A good fit was usually found between the data and the model, with a root-mean-square error averaging 15% of the mean Rrs at 10 Hz. At all frequencies K2 and K3 were substantially and significantly larger, and K1 slightly lower during expiration than during inspiration. Rrs, K1 and K3 were minimum at 20 Hz, while K2 exhibited a strong positive frequency dependence. The decrease of Rrs from 10 to 20 Hz was entirely explained by the variations of its linear component, and its increase from 20 to 30 Hz was largely due to its flow dependent component. Both the phasic variations and the frequency dependence of the coefficients suggest that the model is purely descriptive and that coefficients K2 and K3 reflect a number of phenomena, including the variations in glottic aperture during the respiratory cycle.

Adult↗
PubMed1991

Chlamydia trachomatis developmentally regulated protein is homologous to eukaryotic histone H1.

Chlamydiae are prokaryotic obligate intracellular parasites that undergo a biphasic life cycle involving an infectious, extracellular form known as elementary bodies and an intracellular, replicating form termed reticulate bodies. We have purified from Chlamydia trachomatis a very basic elementary body-specific protein with an apparent molecular mass of 18 kDa, determined its N-terminal amino acid sequence, and cloned the encoding gene. Sequence analysis of the cloned gene revealed some remarkable properties for its expressed product, including a high lysine content (29%), a correspondingly high pI, and significant homology to the H1 class of eukaryotic histones. Furthermore, a monoclonal antibody to this chlamydial histone analog, termed Hc1, displayed immunoblot and antinuclear specificity suggestive of cross-reactivity to H1 histones. The gene was expressed only during the late stages of the chlamydial life cycle concomitant with the reorganization of chlamydial reticulate bodies into elementary bodies, suggesting that the Hc1 protein plays a role in the condensation of chlamydial chromatin during intracellular differentiation.

Amino Acid Sequence↗