The zona pellucida in folliculogenesis, fertilization and early development.
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Animals↗
Biomedical subjects
Ming Zhao
Publications and source records attributed to Ming Zhao.
Activation of the p38 MAP kinase pathway is required for foam cell formation from macrophages exposed to oxidized LDL.
Endocytosis of oxidized low density lipoproteins (oxLDL) by macrophages, mediated by scavenger receptors, is thought to play a central role in foam cell formation and, thus, in the pathogenesis of atherosclerosis. OxLDL activates several MAP kinases, including the ERK, JNK and p38 MAP kinases, but the role of these activations in oxLDL uptake has not been studied. In the present investigation, we find that SB203580, a specific inhibitor of p38, blocks oxLDL-exposed J774 cells from becoming foam cells. Inhibition of foam cell formation by blockade of the p38 pathway is, at least in part, due to inhibition of oxLDL-induced up-regulation of the scavenger receptor CD36. Using pharmaceutical inhibitors and dominant active MAP kinase kinases, we demonstrated that activation of the p38 pathway, but not the ERK or JNK pathways, is necessary and sufficient to transactivate PPARgamma, a nuclear receptor that has recently been shown to play a pivotal role in oxLDL-induced CD36 expression. Our results for the first time demonstrate a regulation of CD36 by p38, and the importance of the p38 pathway in regulation of foam cell formation.
Animals↗
Effect of synthetic oligopeptides on osteoporosis.
The objective of this study was to establish the solution method of GHRPS, the synthetic oligopeptides Tyr-Gly-Gly-Phe-Met-NH2, Tyr-Gly-Gly-Phe-Met-OH, Tyr-Gly-Gly-Phe-Leu-NH2, Tyr-Gly-Gly-Phe-Leu-OH, Tyr-Gly-Gly-Phe-Gly-NH2, and Tyr-Gly-Gly-Phe-Gly-OH, to verify their effect on osteoporosis. Male ICR mice (20+/-2 g) were used. The intramuscular injection dose of 6.3 mg/kg prednisone induced a significant decrease of body and femur weight of the animals. The subcutaneous injection dose of 18 microg/kg synthetic peptide was not effective to prevent the decrease of body and femur weight of the animals. The subcutaneous injection dose of 6.3 mg/kg prednisone elicited a decrease in content of femur calcium and in the level of serum calcium of the animals. The subcutaneous injection dose of 18 microg/kg Tyr-Gly-Gly-Phe-Leu-NH2, or Tyr-Gly-Gly-Phe-Leu-OH, or Tyr-Gly-Gly-Phe-Gly-NH2 significantly increased the content of femur calcium and decreased the level of serum calcium of the animals. It was also observed that the subcutaneous injection dose of 18 microg/kg Tyr-Gly-Gly-Phe-Gly-OH, Tyr-Gly-Gly-Phe-Leu-OH, Tyr-Gly-Gly-Phe-Met-OH, Tyr-Gly-Gly-Phe-Met-NH2 significantly increased the content of femur phosphorous and decreased the activity of ALP of the animals.
Animals↗
Synthesis of RGD containing peptides and their bioactivities.
RGDS, RGDV, and RGDF were used for the structural modification of YIGSR and YIGSK, the sequences involved in the development of metastasis disease. By use of a solution method, YIGSRRGDS, YIGSRRGDV, YIGSRRGDF, YIGSKRGDS, YIGSKRGDV, YIGSKRGDF, YIGSRYIGSK, and YIGSKYIGSR were prepared in good yield. The results of bioassay in vitro indicated that the target property of RGDS, RGDV, and RGDF to high affinity-receptors may be responsible for the enhanced anti-aggregation, anti-adhesion, and anti-invasion potency.
Blood Platelets↗
Conserved furin cleavage site not essential for secretion and integration of ZP3 into the extracellular egg coat of transgenic mice.
The extracellular zona pellucida surrounding mammalian eggs is formed by interactions of the ZP1, ZP2, and ZP3 glycoproteins. Female mice lacking ZP2 or ZP3 do not form a stable zona matrix and are sterile. The three zona proteins are synthesized in growing oocytes and secreted prior to incorporation into the zona pellucida. A well-conserved furin site upstream of a transmembrane domain near the carboxyl terminus of each has been implicated in the release of the zona ectodomains from oocytes. However, mutation of the furin site (RNRR --> ANAA) does not affect the intracellular trafficking or secretion of an enhanced green fluorescent protein (EGFP)-ZP3 fusion protein in heterologous somatic cells. After transient expression in growing oocytes, normal EGFP-ZP3 and mutant EGFP-ZP3 associate with the inner aspect of the zona pellucida, which is distinct from the plasma membrane. These in vitro results are confirmed in transgenic mice expressing EGFP-ZP3 with or without the mutant furin site. In each case, EGFP-ZP3 is incorporated throughout the width of the zona pellucida and the transgenic mice are fertile. These results indicate that the zona matrix accrues from the inside out and, unexpectedly, suggest that cleavage at the furin site is not required for formation of the extracellular zona pellucida surrounding mouse eggs.
Amino Acid Sequence↗
Bone morphogenetic protein 2 induces dental follicle cells to differentiate toward a cementoblast/osteoblast phenotype.
When triggered appropriately, dental follicle cells are considered to be able to differentiate toward a cementoblast/osteoblast phenotype. However, factors and mechanisms regulating follicle cell differentiation remain undefined. This study focused on determining the ability of bone morphogenetic protein (BMP) 2 to promote the differentiation of follicle cells and periodontal ligament (PDL) cells along a cementoblast/ osteoblast pathway. Follicle cells and PDL cells were isolated from the first molar region of CD-1 mice and immortalized with SV40. Both cell types expressed BMP-4 and BMP receptors (BMPR) IA and II, but only follicle cells expressed BMP-2 mRNA. Cells were exposed to recombinant human BMP (rhBMP)-2 (0-100 ng/ml) and Northern blots were used to determine the expression of mineral-associated markers. BMP-2, in a dose- and time-dependent manner, induced cementoblast/osteoblast differentiation of follicle cells, as reflected by enhanced core binding factor alpha (Cbfal), bone sialoprotein (BSP), and osteocalcin (OCN) mRNA expression and enhanced mineral formation. U0126, a specific inhibitor of MEK-1/2 members of the MAPK family, abolished BMP-2-mediated expression of BSP and OCN. In contrast, exposure of PDL cells to BMP-2 resulted in modest expression of OCN and minimal promotion of mineralization. These results suggest that BMP-2 triggers follicle cells to differentiate toward a cementoblast/osteoblast phenotype and that the MAPK pathway is involved.
Animals↗
[16S approximately 23S rDNA internal transcribed spacer sequence analysis and its application in mycobacterial identification].
OBJECTIVE: To study the applicability of the 16S approximately 23S rDNA internal transcribed spacer (ITS) sequences in mycobacterial identification. METHODS: The 16S approximately 23S rDNA ITS sequences of 22 mycobacterial species (30 reference strains and 16 clinical isolates) were determined by PCR-direct sequencing. The sequences determined by this study and those reported in Genbank were analysed by Clustal program (MegAlign Package [Windows Version 4.01]; DNASTAR, Madison, Wis). The percentage similarity of sequence pairs was calculated and a cluster analysis dendrogram was constructed by PHYLIP package. RESULTS: The 16S approximately 23S rDNA ITS sequences among mycobacterial species had highly polymorphism except that Mycobacterium tuberculosis complex (MTC) sequences were highly consistent. The similarity between sequence pairs was 30.4% to 86.5%. Mycobacterial species could be isolated by cluster analysis dendrogram. The results showed that sequence analysis of the 16S approximately 23S rDNA ITS can differentiate MTC from nontuberculous mycobacteria (NTM) and identify NTM at species level. CONCLUSION: 16S approximately 23S rDNA ITS sequences can be used as target genes in mycobacterial identification.
DNA, Bacterial↗
[The value of spiral multi phase scans in the diagnosis of the inflammatory pseudotumor of liver].
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Adult↗
[Discussion of correlative factors and risk in patients with diabetic erectile dysfunction].
OBJECTIVES: To probe into the pathogenesis, prevention and treatment way of diabetic erectile dysfunction (DED). METHODS: The age, course, blood pressure, history of drink and smoke, relationship with DED were investigated in 126 DED patients of 320 diabetes mellitus. RESULTS: The prevalence of DED in male diabetic patients was 39.4% (126/320). It was found by the analysis of Logistic regression that the values of OR rise to 1.8467, 1.2614, 1.4508, 1.3212, 1.2065, 5.3464 (P < 0.01), along with adding of 5 years in course, 10 years in ages, 2% in HbA1C, 4 kPa in systolic blood pressure, positive history of smoking and drinking respectively. CONCLUSIONS: Drinking is the most dangerous factor among all risk factors for occurrence of DED. It is very important to control blood pressure well, and to give up tobacco and drink in preventing occurrence of DED.
Adult↗
Signal Transduction in TNF-alpha-induced c-jun Gene Expression.
Our previous studies demonstrated that p38 mitogen-activated protein (MAP) kinase regulated the c-jun protein expression through phosphorylation of transcription factors of myocyte enhancer factors 2 (MEF2) family. There was a MEF2 binding site in the promoter of c-jun gene. Members of the MEF2 family of trans-cription factors bound as homo- and heterodimers to this MEF2 binding site. Here the potential role of the p38 and BMK1 MAP kinases in the regulation of c-jun expression induced by TNF-alpha was examined. It was shown that p38 MAP kinase up-regulated the transcription activity of MEF2A, while BMK1 MAP kinase up-regulated not only the transcription activity of MEF2A, but also MEF2D. The p38 and BMK1 MAP kinases had coordinated effect on the regulation of c-jun transcription. TNF-alpha induced the formation of MEF2A/MEF2D hete-rodimer. Over-expression of homodimer of MEF2 proteins inhibited c-jun transcription induced by TNF-alpha, while over-expression of heterodimer MEF2A/MEF2D enhanced c-jun transcription induced by TNF-alpha. Phosphorylation of MEF2A and MEF2D by p38 and BMK1 respectively appeared very important in TNF-alpha induced MEF2A/MEF2D heterodimer formation to enhance c-jun gene expression.
Journal Article↗
Strain Energies in Homoatomic Nitrogen Clusters N(4), N(6), and N(8).
Strain energies and resonance energies can be obtained as the energy changes for appropriate homodesmotic reactions using ab initio calculated total energies as the energies of the reactants and products involved. Homodesmotic reactions conserve bond types and preserve valence environments at all atoms, requirements that favor the cancellation of basis set and electron correlation errors in the ab initio energies. In this paper we calculate strain energies and resonance energies for N(4), N(6), and N(8) clusters in a number of chemically significant but, for nitrogen, hypothetical structural forms. The nitrogen cluster strain energies are generally of the same order of magnitude as those of isostructural hydrocarbon clusters, and individual differences can be explained by using the ring strain additivity rule and recognizing the effect of the presence of lone pairs of electrons on nitrogen clusters but not on the hydrocarbons. Resonance energies of the nitrogen clusters are much smaller than those of the comparable aromatic hydrocarbons. The differences can be rationalized by considering the relative strengths of CC and NN single and double bonds. Strain and resonance energies of nitrogen clusters are compared with those previously reported for homoatomic clusters of phosphorus and arsenic. Trends through the series are remarkably similar, but strain energies for clusters from lower periods are progressively smaller. Strain and resonance have been important organizing concepts in organic chemistry for many years. Estimates of corresponding parameters for inorganic analogs are only now becoming available.
Journal Article↗
Three-Dimensional Hückel Theory for closo-Carboranes.
We have recently developed a 3-dimensional Hückel method for cluster compounds. The method uses a set of approximations for Coulomb, resonance, and overlap integrals very similar to those employed in the familiar 2-dimensional Hückel theory for the pi electrons of planar conjugated hydrocarbons. The method can be adapted to heteroatomic clusters by introducing heteroatomic Coulomb integrals, alpha(Y) = alpha(X) + hbeta, whereh is a parameter for heteroatom Y. In this paper, we use the 3-dimensional Hückel method to study the properties of the closo-carboranes, C(2)B(n)()(-)(2)H(n)(). We calibrate the method by choosing a value of the heteroatomic parameter h that distinguishes positional isomers by energy and gives them relative energies in rough agreement with those established by observation and ab initio calculations. We obtain modest improvement in matching ab initio relative energies of isomers by means of a three-parameter, first-order perturbation treatment. We use the calibrated method to evaluate various mechanisms proposed for the isomerizations of C(2)B(4)H(6), C(2)B(5)H(7), and C(2)B(6)H(8), all of which have been observed to undergo intramolecular isomerizations. Rearrangements of C(2)B(6)H(8) have been satisfactorily explained by a single-DSD (diamond-square-diamond) process. Those for C(2)B(5)H(7) require at least two DSD processes, concerted, consecutive, or overlapping. Several different mechanisms have been proposed for the rearrangement of C(2)B(4)H(6). In evaluating intermediate and transition state structures, the 3-dimensional Hückel method gives higher energies to those structures with a larger number of nontriangular faces, a plausible conclusion except that occasionally it is wrong. In comparison with ab initio results, the 3-dimensional Hückel method fails to give low energies for classical structures.
Journal Article↗
The Pellucida Glycoprotein ZP 3-Binding Protein of the Boar Spermatozoa.
Four protein components have been isolated from the CHAPS extract of boar spermatozoa by chromatography on PSL-Sepharose affinity column and cellulose CM-52 ion exchange column sequentially. Both boar sperm protein SP1and SP2 exhibited binding activity with the zona pellucida glycoprotein ZP3 by immobilized zona pellucida glycoprotein binding assay (IZPGBA), and SP2 also showed hemagglutinating activity. The protein SP1 obviously inhibited sperm-oocyte binding when it was preincubated with oocytes. The inhibitory activity of SP1 was related to its concentration. By using Western blot technique and biotinylated ZP3, a Zp3-binding spermatozoa protein with molecular weight of 68 kD was identified, which may be a protein involved in sperm-oocyte binding.
Journal Article↗
Simultaneous determination of steroid composition of human testicular fluid using liquid chromatography tandem mass spectrometry.
A rapid, sensitive, and specific method using liquid chromatography tandem mass spectrometry (LC/MS/MS) has been developed for simultaneous determination of testosterone (T), dihydrotestosterone (DHT), estradiol (E2), and 5alpha-androstan-3alpha, -17beta-diol (3alpha-Diol) within human testicular fluid. Sample pretreatment involved a one-step extraction with diethyl ether. The analytes were separated on a Waters X-Terra C18 (150 mm x 2.1 mm i.d., 3.5 microm) analytical column with acetonitrile/water mobile phase (70:30, v/v) containing 0.1% formic acid using isocratic flow at 0.15 ml/min for 8 min. The column effluent was monitored by tandem mass spectrometry with electrospray positive ionization. Linear calibration curves were generated over the range of 0.1-50 ng/ml for T, 0.02-1 ng/ml for DHT, 0.05-2 ng/ml for E2, and 0.2-10 ng/ml for 3alpha-Diol, with values for the coefficient of determination of >0.99. The overall extraction efficiency was greater than 86% for T, 75% for DHT, 66% for E2, and 60% for 3alpha-Diol. The values for within-day and between-day precision and accuracy were <15%. We measured each of the four steroids in testicular sample volumes of only 20 microl, obtained by percutaneous testicular aspiration. The mean intratesticular testosterone concentration found by LC/MS/MS, 572 +/- 102 ng/ml, was similar to that previously obtained by radioimmunoassay (RIA). The mean intratesticular estradiol concentration was 15.7 +/- 2.3 ng/ml, which also correlated well with RIA measurement. Both DHT and 3alpha-Diol were below the limits of detection by RIA, but could be measured accurately by LC/MS/MS. In conclusion, LC/MS/MS represents a sensitive and accurate means by which to measure four separate steroids within small volume samples of testicular fluid.
Androstane-3,17-diol↗
Differential conjugation of tat peptide to superparamagnetic nanoparticles and its effect on cellular uptake.
Surface modification of superparamagnetic contrast agents with HIV-1 tat peptide has emerged as a promising means for intracellular magnetic labeling and noninvasive tracking of a large number of cell types with MRI. To achieve efficient intracellular delivery of the nanoparticles, we investigated the effect on cellular uptake of superparamagnetic iron oxide particles by varying the number of attached tat peptides. First, we report here a modified P2T method in measuring the numbers of surface attachments per particle through disulfide linkage. The method was shown to have desirable simplicity and reproducibility. With the P2T method as a tool, conjugates with progressively higher ratios of peptide-to-particle were synthesized. We were able to demonstrate that higher numbers of tat peptide facilitate the cellular uptake of iron oxide nanoparticles in a nonlinear fashion. Cells labeled with these optimized preparations were readily detectable by MR imaging. The increase in sensitivity could allow in vivo tracking of 100-fold lower cell concentration than currently described.
Animals↗
Two-dose basiliximab compared with two-dose daclizumab in renal transplantation: a clinical study.
BACKGROUND: Addition of the interleukin-2 receptor (IL-2R) antagonists basiliximab or daclizumab to a calcineurin inhibitor-based regimen significantly reduces risk of acute rejection with a tolerability profile similar to a placebo. Use of a truncated two-dose regimen of daclizumab has been reported, but till date, there has been no controlled study of two-dose daclizumab vs. two-dose basiliximab. METHODS: Deceased-donor renal transplant recipients were randomized to basiliximab (20 mg on days 0 and 4) or daclizumab (50 mg on days 1 and 14) with cyclosporine, mycophenolate mofetil and corticosteroids. Flow cytometry was used to calculate the proportion of CD25(+) T cells in peripheral blood. RESULTS: Thirty patients were randomized to basiliximab and 28 to daclizumab. There was one patient death in each group, with no other graft losses. By six months, the incidence of biopsy-proven acute rejection was 0% with basiliximab vs. 21.4% with daclizumab (p < 0.05). Three patients in the daclizumab group required OKT3 for steroid-resistant rejection. There were no between-group differences in the incidence of infection. The proportion of CD25(+) T cells declined markedly during the first two wk in both groups, but was significantly lower in the basiliximab group during weeks six to eight. CONCLUSION: Two doses of basiliximab are more effective than two 1 mg/kg doses of daclizumab in preventing acute rejection in de novo renal transplant patients receiving cyclosporine, mycophenolate mofetil and corticosteroid maintenance therapy. In patients receiving relatively low-level immunosuppression in order to minimize toxicity, basiliximab may be preferable to a truncated daclizumab regimen.
Adult↗