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Y Z Ji

Publications and source records attributed to Y Z Ji.

7 recordsLinked to original sources
PubMed1998

Human gamete fusion can bypass beta1 integrin requirement.

Since alpha6beta1 integrin has been shown to function as a sperm adhesion receptor in the mouse, we investigated the potential role of beta1 integrin in the gamete fusion process in humans. The expression of beta1 integrin was morphologically analysed by indirect immunofluorescence and confocal microscopy. A homogeneous and intense staining was detected at the plasma membrane, and in some subcortical vesicles of germinal vesicle stage oocytes (GV). Beta1 almost disappeared from oolemma and cytoplasm of metaphase I (MI) oocytes, but was re-expressed as asymmetrical patches at the plasma membrane of metaphase II stage oocytes (MII). A functional fusion assay based on Hoechst or calcein-AM dye transfer from one gamete to the other showed that maturing oocytes were able to fuse with an increasing number of spermatozoa (11-22 from GV to MII respectively), and that fused spermatozoa co-localized with beta1 integrin patches. Human gamete fusion was only partially inhibited either by RGD-containing peptide (GRGDTP), or by blocking anti-human beta1 integrin monoclonal antibody (DE9), with a maximum of 50% inhibition. Despite the combined addition of GRGDTP and blocking mouse anti-human beta1 integrin DE9 in the assay, a complete inhibition of fusion could not be achieved. A mouse polyclonal antibody raised against human oocyte membranes was more potent in inhibiting the fusion. Since beta1 integrin expression at the plasma membrane was not correlated to oocyte fusibility, and since it was only partially inhibited by DE9 and/or RGD peptide, we suggest that human gamete fusion can bypass the beta1 requirement. Beta1 integrin certainly participates in human gamete fusion by acting in co-operation with multiple integrin/disintegrin couples or another cofactor, not yet identified.

Animals↗
PubMed1997

Modifications of the human oocyte plasma membrane protein pattern during preovulatory maturation.

The plasma membrane protein pattern of human oocytes was established using a highly sensitive nonisotopic technique. Unfertilized, 2-day-old metaphase II (MII) and immature oocytes were biotinylated at 4 degrees C and zona pellucida were mechanically removed. Proteins were resolved by 7% SDS PAGE, and electrotransferred to PVDF membranes. Plasma membrane proteins were selectively detected by streptavidin-horseradish peroxidase (HRP) and enhanced chemoluminescence (ECL). Thirteen biotinylated polypeptide bands were identified in MII oocyte plasma membrane (126, 110, 98, 90, 77, 71, 64, 61, 58, 54, 50, 48, 44 kD). During maturation, the total amount of membrane proteins decreased dramatically from the germinal vesicle (GV) to the MII stage oocytes, while the relative proportion of the 71 kD band increased from 9.9% to 13.1% and 27.4% in GV, metaphase I, and MII stage oocytes, respectively. Improvement of the detection technique permitted to establish the protein profile of a single oocyte loaded per lane (n = 12). Five to ten polypeptides were identified, indicating a great polymorphism of the plasma protein pattern, even for oocytes from the same cohort. Hamster and mouse oocyte plasma membrane protein patterns were also investigated with the same technique. Both presented 15 bands, 12 of which had a molecular weight similar to those from the human oocytes. In conclusion, the protein pattern in the human plasma membrane appears qualitatively limited to 13 species, and quantitatively, their amount decreases during oocyte preovulatory maturation. A great polymorphism from one oocyte to another was detected. The protein pattern is highly conserved between human, hamster, and mouse oocytes. This very sensitive technique will allow further studies on the functional significance of this protein pattern.

Animals↗
PubMed1995

[Preimplantation diagnosis of delta F508 mutation of mucoviscidosis in transgenic mice].

OBJECTIVE: The aim of our study was to master preimplantation diagnosis in transgenic mice. METHODS: Stage 4 or 8 cells preembryos were collected from C57BL6xCBAF1 mice, three days after mating with transgenic C57BL6xSJLF1 mice homozygous for the human gene delta F508 mutation of cystic fibrosis. A single blastomere was sampled by microbiopsy and the preembryos transferred in Swiss mice foster mothers. Molecular biology for delta F508 mutation on a single blastomere was performed with a double PCR technique on a Perkin Elmer Cetus 9600. RESULTS: The success rate of biopsy on the 122 preembryos with 4 cells was 90.2%, and 93.8% on the 128 prembryos with 8 cells. The rate of in vitro hatching was 84.6% after biopsy on 52 preembryos with 4 cells (92.2% for controls without biopsy, p > 0.05), and 90.0% for 50 preembryos with 8 cells (94.4% for controls without biopsy, p > 0.05). The rate of birth after biopsy and transfer of 42 preembryos with 4 cells was 66.7% (72.5% for controls transferred without biopsy, p > 0.05) and 70.3% for 37 preembryos with 8 cells (71.9% for controls, p > 0.05). No difference was evidenced for births weight or organ weight at 3 weeks between mice born from biopsied embryos and controls. Thirty-two double PCR were performed for the diagnosis of the cystic fibrosis delta F508 mutation, 20 on a single blastomere obtained by microbiopsy and 12 for various negative controls, with 100% specificity and 100% sensitivity. CONCLUSIONS: Microbiopsy of preembryos with 4 cells or 8 cells does not alter their viability or further development. The double PCR technique on a single blastomere for the cystic fibrosis delta F508 mutation is reliable with our current methods of investigation.

Animals↗
PubMed1993

Microsurgery in the treatment of chyluria and scrotal lymphangial fistula.

Thirty-nine cases of chyluria and scrotal lymphangial fistula treated by microsurgery between April 1980 and October 1989 are presented. Several different methods were used. In males a lymphatico-venous anastomosis of the spermatic cord was performed and in females the lower inguinal lymph nodes were anastomosed to the branches of the greater saphenous vein. In patients with scrotal lymphangial fistulae, bilateral lymphatico-venous anastomosis was carried out after excision of the fistula and scrotoplasty. Thirty-seven patients were followed up for 1 to 9 years, 36 being cured by a single operation.

Adult↗
PubMed1990

Dynamic observation on thyroid function in severe head injury.

The dynamic changes of thyroid hormone levels in patients with severe head injury were observed. The results showed that the serum thyroid hormone levels changed rapidly within several hours after the injury and the mean levels of serum total T3 and T4 (TT3, TT4) decreased while high reverse triiodothyronine (rT3) increased significantly. Serum TT3, TT4 and rT3 levels returned to normal gradually in 2 to 3 weeks after the injury in the surviving group, whereas serum total T4 gradually declined and rT3 steadily increased in the fatal group. The mean levels of serum TSH remained unchanged in both groups. Therefore, the use of the levels of serum thyroid hormones as adjuvant indices can be helpful in making pertinent judgements of the severity and prognosis of severe head injuries.

Adult↗
PubMedDate not supplied

[Evolution of cytoplasmic and membrane parameters during human oocyte maturation].

Human oocyte cytometry was studied during a program of Subzonal Insemination. Oocytes with a diameter over 108 microns presented higher fusiogenic ability than others. Independently of nuclear maturational criteria, the ooplasma growth appears as an important factor of oocyte maturity. Human oocyte plasma membrane protein pattern was assessed using biotinylation technique, western Blot and chemoluminescence (ECL) on 2 days old unfertilized oocytes. The total membrane protein content decreases dramatically from germinal vesicle to metaphase 2 stage oocytes with a relative over expression of the 71 kD. It represents 30% of the total protein content of the mature oocyte membrane. The protein profile, assessed on single oocytes, showed a polymorphism including for oocytes coming from the same cohort. Its functional importance is currently investigated.

Cell Membrane↗