Biomedical subjects

Z Y He

Publications and source records attributed to Z Y He.

At least 19 recordsLinked to original sources

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

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

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↗

PubMed1995

Effects of antioxidants on fiber mutagenesis.

Recent studies from this laboratory have shown that asbestos fibers are mutagenic in cultured mammalian cells when assayed using a system that can detect multilocus deletions. Southern analysis of the induced mutants shows that the majority contain large deletions ranging in size from a few thousand to several million basepairs. In the present study, the effects of free radical scavenging enzymes on the cytotoxic and mutagenic potential of chrysotile fibers were examined using the human-hamster hybrid (AL) cells. Exponentially growing cells were treated with graded doses of fibers for a 24 h period either in the presence or absence of catalase, superoxide dismutase (SOD) or Tempol. Fiber-exposed cells were treated with the various enzymes either concurrently with the fiber or extended through the entire expression period. While the survival of AL cells treated with graded doses of chrysotile fibers with or without a concurrent treatment with SOD and catalase was not significantly different, the mutation yield at the S1 locus was significantly reduced in cells treated with these antioxidant enzymes. Furthermore, cells treated with the enzymes for a prolonged period were not better protected than those treated only during fiber treatment. The SOD mimic nitroxide, Tempol, had no effect on either the survival or mutagenic yield of chrysotile fibers. While SOD and catalase reduced the mutagenic potency of asbestos fibers in AL cells, they did not alter the molecular spectrum of fiber-induced mutagenesis. Our results indicate that antioxidant enzymes can protect cells against the genotoxic damages induced by chrysotile fibers, and are highly suggestive of the roles of oxyradicals in the fibrogenic and carcinogenic mechanisms of asbestos fibers.

Animals↗

PubMed1995

Effects of toquipidine on ionic channels of cultured embryonic Xenopus laevis myoblasts and neurons.

AIM: To study the effects of toquipidine (1-p-methyl-phenyl-2-(alpha-piperidinoacetyl)-1, 2, 3, 4-tetrahydroisoquinoline hydrochloride, Toq), a new anti-arrhythmic agent first synthesized in China, on ionic channels. METHODS: Ionic channel currents were recorded by whole-cell patch clamp technique in cultured embryonic Xenopus laevis myoblasts and neurons. RESULTS: Toq (0.1, 1, 10, and 100 mumol L-1) caused a concentration-dependent inhibition of the Na+ currents with IC50 7.2 mumol L-1 (5.3-9.8 mumol L-1). Toq (10 mumol L-1) also suppressed the high-voltage-activated Ca2+ currents in neurons. But the steady-state outward K+ currents in myoblasts were activated by Toq (10 mumol L-1). CONCLUSION: Toq blocked the Na+ and Ca2+ channels and opened the steady-state outward K+ channels.

Animals↗

PubMed1994

Time-varying adaptive filters for evoked potential estimation.

Adaptive implementation of an optimal time-varying filter (TVF) for evoked potential (EP) estimation is addressed in this paper. A data-adaptive scheme is used, which converges asymptotically to the optimal TVF solution. Two basic adaptive TVF's (ATVF's) are first introduced, namely least mean square (LMS) ATVF and recursive least-squares (RLS) ATVF. The latter converges much faster than the former. Since the basic ATVF's usually require a relatively large set of response trials to get a meaningful solution, a reduced-order ATVF is further presented and the corresponding LMS and RLS (including a fast RLS) adaptive algorithms are developed. To save memory, a truncated Fourier expansion is suggested to express approximately the time-sequenced weight-vectors of the ATVF's, resulting in a simplified reduced-order ATVF. Finally, extensive simulations are provided to confirm the superior performance of the ATVF's. The present ATVF's can be used as prefilters for latency-corrected average (LCA) processing to obtain more informative estimates of EP signals.

Adult↗

PubMed1994

Peak component latency-corrected average method for evoked potential waveform estimation.

A peak component latency-corrected average (PC-LCA) method consisting of three steps is presented for estimating the evoked potentials (EP) in the human brain. The present PC-LCA is essentially an alternative version of the original LCA method developed by McGillem et al. It first uses a time-varying adaptive filter as a preprocessor to suppress the ongoing EEG and to enhance the EP. Then, the statistics of mean latencies and amplitudes of the EP peak components are estimated by a peak detection and alignment procedure. The final waveform estimate is obtained by superimposing the estimated mean peak components on background information and subsequently fitting a truncated Fourier series using the fast Fourier transform (FFT). Consistent estimates of the EP peak component information are established based on asymptotic analysis of the PC-LCA. Finally, real-time implementation of the PC-LCA is considered, and the superior performance of the PC-LCA method is confirmed by detailed numerical results.

Electroencephalography↗

PubMed1993

The relationship between cytosolic free [Ca2+]i concentration and intracellular cAMP of platelet at various stages of experimental atherosclerosis in rabbits.

The relationship between cytosolic free [Ca2+]i and intracellular cAMP of platelet at various stages of experimental atherosclerosis in rabbits was studied. The results showed that the increase of [Ca2+]i was negatively correlated with the level of cAMP in cholesterol-fed rabbits (r = -0.667, P < 0.001) for 2, 4, 8 and 12 weeks. The viscosity of the whole blood at shear rates of 230.4/s and 5.76/s increased only in rabbits fed with cholesterol for 2 weeks, but the plasma viscosity increased in those fed for 2 and 4 weeks.

Animals↗

PubMed1992

Chrysotile fiber is a strong mutagen in mammalian cells.

Although chrysotile asbestos is a proven human carcinogen, several studies have concluded that these fibers are not mutagenic to cultured mammalian cells. We show here, on the other hand, that when tested using the AL cell system that detects both intragenic and multilocus mutations, chrysotile is indeed mutagenic and comparable in strength to that of gamma-rays. Southern analysis of the induced mutants shows that the majority contains large deletions ranging in size from a few thousand to several million base pairs. Results of our study demonstrate that, while chrysotile may be less durable in vivo than the amphibole fibers such as crocidolites and amosites, it can effectively create genetic damage involved in the cancer process.

Animals↗

PubMed1992

Mechanism of oncogenicity for bioreductive drugs.

The oncogenic transforming potential of a series of bifunctional bioreductive drugs were examined under either aerated or hypoxic conditions to assess the contribution of side chains or nitroreduced products toward their carcinogenic mechanisms. Both the cytotoxicity and transforming effects of these drugs increased as a function of dose under hypoxia. In air and at doses that resulted in comparable cell killing, RSU-1069 and RB-88716 were substantially more oncogenic than RSU-1164 or SR-4233. In nitrogen, the oncogenicity of SR-4233 as a function of survival increased, whereas the transforming effect for the aziridine-containing drugs, RSU-1969 and RB-88716, decreased. These data suggest that, among the drugs examined, the transforming moiety in air is largely a function of the alkylating aziridine group. In hypoxia, the reduction of the nitro-moiety to the corresponding active metabolites may be responsible for much of the transformation observed.

Animals↗

PubMed1990

Ultrastructural circadian variation of mast cells in the pinna of the mouse.

It has been found previously under the light microscope that there was a circadian variation in mast cell number in the pinna of mice. The mast cell number was increased at 18.00 h and decreased at 06.00 h. In the current study, 5 mice of each group were synchronized for 4 weeks with a standard lighting regimen (light: 06.00-20.00 h; dark: 20.00-06.00 h). Both pinnas of every mouse of each group were removed at 06.00, 12.00, 18.00 and 24.00 h, respectively. Under the electron microscope, it was observed that more degranulated mast cells were found at 06.00 h and more intact mast cells were visible at 18.00 h. It appeared that the mast cell numbers, decreased and increased under the light microscope, were due to mast cell degradation and regranulation. This finding suggests that a functional circadian variation exists in the mast cell under physiological conditions.

Animals↗

PubMed1990

Studies with bifunctional bioreductive drugs. I. In vitro oncogenic transforming potential.

The oncogenic transforming potential of a series of bioreductive drugs including RSU-1069 and its various alkyl-substituted derivatives, RB-7040, RB-88716, RSU-1164, and RB-88712, has been compared using the C3H 10T1/2 cell system. While the aziridine moiety at the terminal end of the side chain confers greater cytotoxicity to both the 2-nitroimidazole (RSU-1069) and the 5-nitrofuran (RB-88716), it also increases the oncogenic transforming potential of the drugs correspondingly. By substituting the aziridine ring with methyl groups, the cytotoxicity and oncogenicity of these bioreductive drugs decrease in a way that is proportional to the degree of methylation. A clear structure-activity relationship can be demonstrated from these methyl-substituted derivatives such that a tetramethyl-substituent (RB-7040) is much less cytotoxic and oncogenic than a dimethyl-substituent (RSU-1164). RB-7040, which has in vitro and in vivo sensitizing efficiency comparable to the parental compound RSU-1069, is roughly tenfold less cytotoxic and, at concentrations that achieve an in vitro enhancement ratio of 2.9, induces a transforming frequency that is indistinguishable from the spontaneous rate.

Animals↗

PubMed1989

Quantitative study of circadian variations in mast cell number in different regions of the mouse.

The tongue, pinna and dorsal skin of adult male C-1 mice were removed at 03.00, 06.00, 09.00, 12.00, 15.00, 18.00, 21.00 and 24.00 h, fixed in basic lead acetate and stained with Alcian blue-safranin or 0.5% toluidine blue. The mast cell numbers of these regions were counted and analyzed statistically by analysis of variance. It was found that there were circadian variations in the mast cell number in the tongue, pinna and dorsal skin. The difference between the minimum and maximum of circadian variation in mast cell number in all three regions was highly significant (p less than 0.01). Furthermore, the time points of the maximum and minimum of mast cell number varied between the different regions. The time point of the minimum in the tongue and pinna was at 06.00 h, whereas it was at 09.00 h in the dorsal skin. The time point of the maximum in the tongue and dorsal skin was at 21.00 h, but in the pinna it was at 18.00 h.

Animals↗