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Z Y He

Publications and source records attributed to Z Y He.

At least 19 recordsLinked to original sources
PubMed2005

Growth mechanism and ultraviolet-light emission of the self-assembled complex of MgO nanostructures.

Bulk-quantity net-like nanodendrites and four-fold hierarchical nanostructures were synthesized by direct thermal evaporation and oxidation of metallic Mg powder. Their formation mechanism is explained using the self-catalytic vapor-liquid-solid mechanism together with dendritic-crystal epitaxial growth mechanism. Four-branch and eight-branch nanodendrites were also detected. The photoluminescence spectrum reveals that the peak with the maximum intensity is centered at about 3.16 eV (392 nm). Through Gaussian fitting, a strong and narrow ultraviolet-light emission peak centered at 3.16 eV (392 nm) and a relatively weak but broad blue-light emission band centered at 2.74 eV (453 nm) were observed in the photoluminescence emission spectrum, which are respectively attributed to the recombination luminescence of the F+ and F centers (belonging to oxygen-vacancy related defect levels) in the MgO nanostructures. In addition, another very weak and broad red-infrared emission band can also be detected, which is probably due to the relaxation luminescence of impurity levels in the MgO nanostructures.

Crystallization↗
PubMed2001

[Identification of the existence of luteinizing hormone in pituitary vacuoles of rats].

It is generally believed that glycoprotein hormone exists in granules of the gonadotrophin (GTH) cells, and recent studies on the formation and secretion of glycoprotein hormones also concern much on the changes in the pituitary granules. In our previous studies, it was found that the secretion of luteinizing hormone (LH) was closely related to the morphological changes in pituitary vacuoles of rats, and the morphology of GTH cells was also closely related to the changes in vacuolar morphology. Therefore, it appears that there exists an inseparable relationship between the storage and secretion of LH and pituitary vacuoles. In order to examine whether the pituitary vacuoles contain LH in rats, and to further explore if LH is stored and released by the pituitary vacuoles, the vacuoles were separated and purified from pituitary, cortex and liver tissues by density gradient centrifugation. The vacuolar protein components, LH and glycoproteins were determined by the methods of SDS-PAGE, Western immunoblot and Con A/HRP, respectively. The results showed that (1) abundant protein components with various molecular masses were present in the vacuoles of the pituitary, cortex and liver in male, female and ovariectomized rats, and some of the protein components were similar in the molecular mass; (2) both pituitary tissues and vacuoles contained LH, and their LH levels had no significant difference by quantitative analysis of extracted protein samples; and (3) glycoproteins of various molecular masses were found in the vacuoles of the pituitary, cortex and liver, but the same position of stained glycoprotein band and LH molecular mass was only observed in the pituitary vacuoles. From the results given above, it can be concluded that LH specifically exists in the pituitary vacuoles, although there are some similar protein components in various cellular vacuoles. The possibility was further demonstrated at the molecular level that the pituitary vacuoles may have the function of storing and releasing LH due to the pituitary vacuoles containing LH with assembled glycone.

Animals↗
PubMed2001

[Inositol 1,4,5-triphosphate receptors (IP(3)Rs) in myocardial nuclei involved in pressure overload-induced hypertrophy of rat heart].

In order to clarify the importance of nuclear IP(3)Rs in the development of myocardial hypertrophy, a hypertensive rat model was established by abdominal aortic constriction, and velocity and isopyknic gradient centrifugation was employed to fractionate the cardiac nuclei. The maximal number of binding sites (B(max)) and dissociation constant (Kd) of IP(3) to the nuclear envelopes were measured by [(3)H] IP(3) binding assay. The existence of IP(3)Rs on myocardial nuclear envelope was confirmed. [Ca(2+)] inhibited [(3)H] IP(3) binding to its receptors in cardiac nuclear envelopes in a concentration-dependent way. Phosphorylation by CaM and endogenous PKC decreased B(max) of nuclear IP(3) receptors. B(max) and Kd of nuclear IP(3)Rs were increased by 1.217 (P<0.01) and by 2.149-fold (P<0.01) respectively in hypertrophic myocardium as compared with those of the control. The above results suggest that IP(3)Rs exist in myocardial nuclei and are down regulated by CaM, PMA and free Ca(2+). The increase of the binding sites of IP(3)Rs in the nuclear envelopes and the decrease of their affinity might play importment roles in the development of overload induction of cardiac hypertrophy.

Animals↗
PubMed2000

Human glial cell-line-derived neurotrophic factor: a structure-function analysis.

Glial cell-line-derived neurotrophic factor (GDNF) is a protein known to enhance the survival of dopaminergic and motor neurons. It has been shown to have therapeutic potential in the treatment of Parkinson's disease and other neurodegenerative diseases. GDNF gene was modified by deletion and insertion mutagenesis using PCR methods. The various mutants were all highly expressed in Escherichia coli. The recombinant proteins were purified and their survival-promoting activities were determined by motor neurons. The result showed that the C-terminus was critical for structure stability of GDNF, and the alpha-helix, finger1 and finger2 regions were involved in receptor binding, while the N-terminus was not essential for the biological functions of GDNF.

Animals↗
PubMed2000

Expression of apoptosis-related genes in human oocytes and embryos.

PURPOSE: The objective was to study whether apoptosis occurs in human embryogenesis. METHODS: Human viable, arrested, and nonviable embryos and immature, and nonfertilized oocytes donated by our patients were used to detect apoptosis by Tunel labeling, annexin staining, and single-cell reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: DNA fragmentation and phosphotidylserine translocation, the two markers for apoptosis, were detected frequently in fragmented human embryos derived from in vitro fertilization-embryo transfer (IVF-ET). Using RT-PCR, apoptotic genes also were detected in these embryos. The frequencies of gene expression in viable embryos, arrested embryos, nonviable embryos, immature oocytes, and non-fertilized oocytes were: 7/8, 5/5, 5/6, 0/6, 0/3, for Bax; 8/8, 5/5, 7/7, 0/4, 0/5 for Fas; 2/8, 0/2, 0/3, 0/5, 0/3 for BCL-2; 0/8, 1/3, 0/2, 0/3, 0/2 for Fas-ligand; and 8/8, 17/17, 21/21, 24/24, 15/15 for actin, respectively. CONCLUSIONS: Our preliminary data did not show a significant difference in the expression frequency of all studied genes between viable embryos and nonviable or arrested embryos. However, the expression of Bax and Fas was noticeably higher in nonviable embryos than in viable embryos as judged by the intensities of amplicons visualized after ethidium bromide staining. In addition, BCL-2 was only detected in viable embryos. Whether embryos quality is related to the regulation of BCL-2, Bax, and Fas expressions requires further study.

Actins↗
PubMed2000

[Cloning of the zot gene of Vibrio cholerae and its expression in Escherichia coli].

The zot gene encoding Zonula occludens toxin was amplified from classic Vibrio cholerae genomic DNA by PCR. The result of sequencing indicated that zot gene encodes 399 amino acid residues. The sequence of zot gene was a little bit different from that of reported including 14 nucleotides and four amino acid residues. The expression plasmid pET-ZOT was constructed by inserting zot gene into plasmid pET-28a(+) containing the T7 promoter. The expression plasmid was induced into E. coli BL21 (DE3) and expression strain BLZOT was selected. SDS-PAGE analysis revealed that the ZOT protein was expressed and accumulated up to above 15% of bacterial soluble protein after induced by IPTG. A protein of 47 kD was expressed as including body. Western blot analysis revealed that the expressed protein was ZOT.

Base Sequence↗
PubMed2000

[Relation between myocardial cAMP and renin-angiotensin system activation after acute pressure overload].

In order to investigate the relationship between cAMP and myocardial renin-angiotensin system activation after acute pressure overload, an animal model of acute pressure overload was established by constriction of abdominal aorta. It was found that angiotensin converting enzyme (ACE) mRNA and protein expression were increased markedly, ACE activity and angiotensin II content were also elevated significantly in rat heart 1 h after acute pressure overload, and the increases were kept at high level. Meanwhile the myocardial cAMP concentration was increased significantly at 0.5 h, reached the peak at day 5, and returned to normal at day 30 after operation. Then cardiomyocytes were cultured to observe whether ACE gene expression can be induced by cAMP. The results showed that elevation of cAMP content in cultured cardiomyocytes stimulated by isoproterenol (ISO, 0.01 micromol/L) increased ACE mRNA and protein expression, and also increased ACE activity and Ang II content in cultural medium. These results suggest that cAMP plays a role in the mechanism of activation of myocardial renin-angiotensin system induced by pressure overload.

Animals↗
PubMed1999

Human endometrial stromal cells improve embryo quality by enhancing the expression of insulin-like growth factors and their receptors in cocultured human preimplantation embryos.

OBJECTIVE: To demonstrate the mechanism by which human endometrial stromal cells improve embryo quality in coculture. DESIGN: Randomized study. SETTING: Academic research center. PATIENT(S): Patients undergoing IVF-ET. INTERVENTION(S): Donated human embryos were cultured randomly either alone (group A) or with human endometrial stromal cells (group B), and the embryonic expression of insulin-like growth factors (IGFs) and their receptors was detected by reverse transcriptase polymerase chain reaction after culture. MAIN OUTCOME MEASURE(S): The embryo frequency distribution of groups A and B before and after culture and the embryonic transcripts of the IGF family genes of the two study groups after culture were compared. RESULT(S): The embryo frequency distribution of the day 3 embryonic stages in groups A and B was not different. However, after culture, a statistically significant difference in blastocyst formation was observed between groups A and B. A significant increase in the expression of IGF-1, IGF-2, the IGF-1 receptor, and the insulin-receptor also was noted. Among the embryos that reached the blastocyst stage, the expression of IGF-1 and the IGF-1 receptor also was significantly different in the two study groups. CONCLUSION(S): Human endometrial stromal cells enhanced the expression of IGFs and their receptors in cocultured human embryos, which may be essential for improving embryo quality.

Blastocyst↗
PubMed1999

Recycling of a single human blastomere fixed on a microscopic slide for sexing and diagnosis of specific mutations by various types of polymerase chain reaction.

OBJECTIVE: To investigate the suitability of recycling single blastomeres to assess multiple genetic variables for preimplantation genetic diagnosis. DESIGN: Prospective randomized study. SETTING: An academic medical center. PATIENT(S): Patients undergoing IVF-ET. INTERVENTION(S): Blastomeres were disaggregated from donated embryos obtained from patients. MAIN OUTCOME MEASURE(S): Polymerase chain reaction (PCR) amplification products. RESULT(S): Fifty-eight blastomeres individually fixed on slides were separated into four groups. Sequential PCRs (group I, n = 30), primed in situ labeling (PRINS) before five sequential PCRs (group II, n = 10), staining with hematoxylin before performing five sequential PCRs (group III, n = 11) and preamplification of whole DNAs by degenerate oligonucleotide primer (DOP) before performing PCR were executed. The amplification efficiencies of five sequential PCRs were 100%, 100%, 96.6%, 83.3%, 56.7% for group I; 100% 100%, 100%, 80%, 40% for group II; 54.5%, 36.4%, 18.2%, 9.1% for group III; and 100%, 100%, 100%, 100%, 100% for group IV. CONCLUSION(S): Blastomeres fixed for PRINS can be recycled for PCR to obtain more genetic information. Hematoxylin staining appears to increase the incidence of failed amplification. Preamplification of whole genomic DNAs by DOP-PCR appears to facilitate diagnosis with high efficiency.

Blastomeres↗
PubMed1999

Expression of inhibin/activin subunits and their receptors and binding proteins in human preimplantation embryos.

PURPOSE: Our purpose was to study the role of inhibin/activin during embryogenesis. METHODS: Transcripts of inhibin/activin subunits (alpha, beta A, beta B), activin receptors (types I and II), and follistatin were detected by a reverse transcriptase-polymerase chain reaction in human reproductive cells and preembryos cultured alone or co-cultured with human endometrial cells. RESULTS: Transcripts of alpha, beta A, beta B subunits were all detected in granulosa luteal cells, but only beta A units were detected in endometrial stromal and decidualized cells. In human preimplantation embryos, none of these subunits were detected in embryos from the four-cell to the morula stage and only beta A subunits were detectable in blastocyst embryos. Activin receptors were detectable in all of the studied embryos and cells. Transcripts of beta A, activin receptors, and follistatin were differentially expressed in human preimplantation embryos cultured in vitro and their expressions were significantly enhanced with the presence of endometrial stromal cells. CONCLUSIONS: Our data suggest that there is a possible endometrium-embryo interaction via endometrial activins and preimplantation embryo receptors and that the embryonic expressions of these activins, their receptors, and binding proteins are dependent on embryonic stage.

Activin Receptors↗
PubMed1999

Expression of the insulin-like growth factor-1 gene and its receptor in preimplantation mouse embryos; is it a marker of embryo viability?

Recent studies have demonstrated the importance of insulin-like growth factors (IGF) in mouse preimplantation development. We examined IGF-1 and IGF-1 receptor (IGF-1R) gene expression in a single blastomere of an early mouse embryo and compared it with subsequent embryo development in culture. Fertilized eggs and 2-cell embryos were obtained by tubal flushing in superovulated and mated female mice. Single cells were removed from embryos at cleavage stage between 3 and 8 cells using the standard embryo biopsy techniques. Individual blastomeres from each embryo were then assayed for the presence of IGF-1 and IGF-1R mRNA using reverse transcription-polymerase chain reaction. The biopsied embryos were washed in medium and placed in co-culture with murine endometrial cells. Embryonic development in culture was assessed and blastocyst grading was performed. IGF-1 gene expression was then examined for an association with in-vitro development. Eighty-seven embryos were biopsied. IGF-1R gene expression was detected in the majority of embryos tested and IGF-1 gene expression was detected in 34 of 81 (42%) embryos. A significant association between IGF-1 expression and blastocyst formation in vitro was found (P < 0.01). There was no association between IGF-1R expression and subsequent embryo development. We conclude that IGF-1 gene expression could potentially be used as a marker of embryo quality.

Actins↗
PubMed1999

Tuberculosis versus lymphomas in the abdominal lymph nodes: evaluation with contrast-enhanced CT.

OBJECTIVE: Tuberculosis in the abdominal lymph nodes may be difficult to distinguish from lymphomas. This study evaluated specific CT imaging criteria for differentiating these entities. MATERIALS AND METHODS: We retrospectively reviewed the anatomic distribution and CT enhancement patterns of disease in 69 patients, 26 (38%) with tuberculosis and 43 (62%) with untreated lymphomas involving abdominal lymph nodes. Of the patients with tuberculosis, five (19%) had disseminated disease and 21 (81%) had nondisseminated disease. Of the patients with lymphomas, 16 (37%) had Hodgkin's disease and 27 (63%) had non-Hodgkin's lymphoma. RESULTS: Disseminated and nondisseminated tuberculosis involved predominantly lesser omental, mesenteric, anterior pararenal, and upper paraaortic lymph nodes. Lower paraaortic lymph nodes were involved more often in Hodgkin's disease (15 patients [94%]), non-Hodgkin's lymphoma (24 patients [89%]), and disseminated tuberculosis (five patients [100%]) than in nondisseminated tuberculosis (one patient [5%]). Mesenteric lymph nodes were involved more often in disseminated tuberculosis (four patients [80%]) and nondisseminated tuberculosis (11 patients [52%]) than in Hodgkin's disease (one patient [6%]) (p < .01). Anatomic distribution was not different between disseminated tuberculosis and non-Hodgkin's lymphoma. Tuberculous lymphadenopathy commonly showed peripheral enhancement, frequently with a multilocular appearance, whereas lymphomatous adenopathy characteristically showed homogeneous attenuation (14 patients [87.5%] with Hodgkin's disease and 19 patients [70%] with non-Hodgkin's lymphoma [p < .01]). CONCLUSION: Our findings indicate that the anatomic distribution and specific enhancement patterns of lymphadenopathy seen on contrast-enhanced CT can be useful in differentiating between tuberculosis and untreated lymphomas of the abdominal lymph nodes.

Abdomen↗
PubMed1997

Simultaneous detection of multiple gene expression in mouse and human individual preimplantation embryos.

OBJECTIVE: To detect simultaneously multiple gene expression in mouse and human individual embryos by reverse transcriptase-polymerase chain reaction. DESIGN: Transcripts involved in the insulin-like growth factor (IGF) system were detected in mouse and human preimplantation embryos. SETTING: An academic teaching hospital. MAIN OUTCOME MEASURE(S): Transcripts of the IGF family genes. RESULT(S): In the mouse, genes are expressed differentially and messenger RNA transcripts of maternal origin in nonfertilized ova decline gradually until the initiation of the embryonic genome transcription. Insulin-like growth factor-binding protein-2 (IGFBP)-2, -3, -4, and beta-actin transcripts appear to be initiated at the two- to four-cell stage, whereas IGFBP-1, -5, and -6 transcripts are initiated at later stages. Transcription, once initiated, appears to continue through to the blastocyst stage. In humans, almost all genes of the IGF system were expressed in preimplantation embryos. This is the first report of the assessment of IGF family transcripts in individual embryos, and introduces a novel method for research and clinical diagnosis of preimplantation embryos.

Actins↗
PubMed1997

Hormonal regulation of expression of messenger RNA encoding insulin-like growth factor binding proteins in human endometrial stromal cells cultured in vitro.

To investigate the presence of messenger RNA (mRNA) encoding insulin-like growth factor binding proteins (IGFBP) in human secretory endometrial stromal cells cultured in vitro, total cellular mRNA and protein extracted from cells treated with various hormones were detected and identified by Northern and Western blotting techniques respectively. Northern blot analysis detected 1.4 and 2.5 kilobase (kb) mRNA transcripts for IGFBP-2 and IGFBP-3 respectively, in both control and progestin-treated human endometrial stromal cells in vitro. However, the 1.5 kb mRNA transcript of IGFBP-1 was detected only in progestin-treated cells but not in the controls. Progestin alone markedly stimulated cellular BP-1 protein and mRNA, but only moderately stimulated cellular IGFBP-2 and IGFBP-3 protein mRNA in a dose-dependent fashion. Adding relaxin at the same time as progestin further enhanced the stimulatory effects of progesterone. Oestradiol had a stimulatory effect on cellular IGFBP-2 mRNA, but had an inhibitory effect on protein and mRNA of IGFBP-3, also in a dose-dependent fashion. In general, for each specific binding protein, the amount of cellular mRNA correlated well with the amount of cellular protein. Therefore, IGFBP protein and mRNA transcript in human secretory endometrial stromal cells appears to be under hormonal influence. These hormones may control the synthesis of IGFBPs at the transcription rather than the translation level.

Cells, Cultured↗
PubMed1997

Expression of IGFs and their receptors is a potential marker for embryo quality.

PROBLEM: Insulin-like growth factors (IGFs) and insulin have been demonstrated to stimulate oocyte maturation and embryo development. Therefore, the expression of IGFs and their receptors may be an important intrinsic factor for embryo growth and may be a potential marker for embryo quality. METHOD OF STUDY: Thirty donated day 3 embryos were cultured in vitro for an additional 3 days to observe their developmental potential and were semiquantitatively analyzed for the expression of IGF-I, IGF-II, IGF-IR, IGF-IIR, and insulin-R. RESULTS: Our results show that the activity of these gene expressions correlates well with the morphological assessment and that high and more gene expressions were often associated with embryos of high growth potential. CONCLUSION: The IGF system may indeed play an important role in human embryogenesis; IGF gene expressions can be a good indicator of embryonic developmental stage and/or growth potential; finally, the IGF system can serve as a marker for embryo quality.

Base Sequence↗
PubMed1997

[An image analysis of the morphological changes of LH cells during LH release peak induced by LHRH in male rats].

The relationship between the peak of LH release induced by exogenous LHRH and morphological change of LH cells in male rats was investigated by ABC Affinity histochemistry and qualitatively characterized by Medical Image Processing System-I. The serum LH concentration was determined by RIA. During the period of basal secretion of LH (3.76 +/- 0.39 ng/ml), the LH cells might be assigned at a storage state. Most of such cells (56.7%) are round and large, and their cross sectional areas are larger then 340 micron 2, usually containing large vacuoles, while the smaller cells of X-sectional area less then 190 micron 2 counted only 2% of the total population. Thirty minutes after injection of LHRH the serum LH level increased significantly (6.46 +/- 1.6 ng/ml, P < 0.01), there appeared a lot of small angular cells, the average cross sectional areas of LH cells decreased significantly (P < 0.0001). When LHRH was injected at sixty minutes, the LH level reached a peak (18.78 +/- 0.79 ng/ml), the number of the large cells decreased to only 4%, while the small cells increased to 66%, vacuoles were almost disapperanced and a large part of cells (52.6%) became irregular. Thereafter, the LH serum gradually subsided to its original basal level with attendant resumption of the morphology of the LH cells at storage state. It appears that the morphological changes, such as size, shape, vacuoles and so on, of the LH cells may serve as an important index for showing the effect of LHRH on LH secretion.

Animals↗
PubMed1996

[Effect of shenmai injection on local defence mechanism in peritoneal dialysis rats].

The local defence mechanism of peritoneal cavity plays an important role in preventing peritonitis during peritoneal dialysis. In this experiment, the effect of Shenmai injection (SI) on the defence mechanism was studied in the remnant kidney model. The results showed that the SI which was added into dialysate could significantly increase the concentration of IgG, C3 in peritoneal cavity (P < 0.05). There was insignificant change in the number of peritoneal macrophages, but the index and the percentage of phagocytosis had the tendency to increase (P > 0.05). SI also relieved the injury of peritoneal mesothelia cells. All these results suggested that the SI had the ability to augment the peritoneal local defence mechanism.

Animals↗