Biomedical subjects

Zhenping Zhang

Publications and source records attributed to Zhenping Zhang.

8 recordsLinked to original sources

PubMed2004

Pre-B cell leukemia transcription factor (PBX) proteins are important mediators for retinoic acid-dependent endodermal and neuronal differentiation of mouse embryonal carcinoma P19 cells.

Pre-B cell leukemia transcription factors (PBXs) act as cofactors in the transcriptional regulation mediated by Homeobox proteins during embryonic development and cellular differentition. PBX1 protein is expressed throughout murine embryonic development, and its deletion in mice disrupts chondrogenesis. PBX protein levels are also increased in mouse embryonal carcinoma P19 cells during retinoic acid (RA)-induced differentiation. To elucidate the role of PBX proteins in this process, we stably overexpressed PBX1b antisense mRNA in P19 cells (PBX1b-AS cells). PBX1b-AS cells did not differentiate to neuronal or endodermal cells following treatment with RA suggesting PBX proteins are required for both processes. Furthermore we demonstrated that PBX proteins regulate the RA-dependent induction in the mRNA levels of bone morphogenetic protein 4 (BMP4) and Decorin (DCN) in P19 cells using both PBX1b-AS cells and PBX1 small interfering RNA. Chromatin immunoprecipitation assays further demonstrated that PBX proteins directly bind to the promoter of Bmp4 and Dcn in vivo in a RA-dependent fashion. In addition, type I and type II BMP receptor mRNA levels were also increased in P19 cells following RA treatment; however, this was PBX-independent. Taken together these data demonstrate that PBX proteins are required for RA-induced differentiation of P19 cells and that PBX proteins regulate the expression of BMP4 and DCN during this differentiation process.

Animals↗

PubMed2002

[Tear film changes after phacoemulsification].

OBJECTIVE: To evaluate tear film changes after phacoemulsification. METHODS: This prospective randomized study involved 68 consecutive patients with age-related cataract (79 eyes) who underwent phacoemulsification. Tear break-up time, Schirmer I test (S I t) value, corneal fluorescein staining, tear film pattern by DR-1 tear interfermetry and the height of tear meniscus were measured preoperatively and 1 day and 2, 7, 14, 30, 180 days postoperatively. RESULTS: At 1 day and 2 days postoperatively, the mean tear break-up time reduced greatly, and the number of patients who showed III to V tear film pattern, the mean S I t value, the height of tear meniscus and fluorescein staining scores increased significantly (P < 0.001 for day 1, P < 0.005 for day 2). S I t value at 7 days postoperatively (P = 0.831) and the height of tear meniscus at 14 days returned to their preoperative values (P = 1.000). The tear break-up time, corneal fluorescein staining scores and the grades of tear film pattern all recovered at 30 days postoperatively (P > 0.05). At 30 days postoperatively, 19.3% of patients showed shorter tear break-up time and less S I t value than that of preoperative day. In addition, 1/9 of the patients with normal preoperative tear film experienced dry eye at 30 days postoperatively. The cases with tear break-up time < 10 seconds compared to patients with tear break-up time >/= 10 seconds were more easily to show tear instability postoperatively (relative risk 13.5, 8.25, 20.0, 39.0, 8.6, 3.9 at 1 day and 2, 7, 14, 30, 180 postoperative days, respectively). CONCLUSION: Phacoemulsification significantly alters the tear break-up time, S I t value, corneal fluorescein staining, tear film pattern and the height of tear meniscus. Some patients with normal tear film may experience dry eye after surgery. Patients with preexisting tear break-up time < 10 seconds are easily at risk of experiencing the tear film instability postoperatively.

Aged↗

PubMed2002

Detection of EP1 and FP receptor mRNAs in the iris-ciliary body using in situ hybridization.

OBJECTIVE: To determine the expression of E-prostanoid1 (EP(1)) and F-prostanoid (FP) receptor mRNAs in iris-ciliary bodies of the human eye using in situ hybridization. METHODS: EP(1) and FP receptor mRNAs were detected by riboprobes labeled with digoxigenin on paraffin sections of the iris-ciliary body tissue of the human eye using in situ hybridization. RESULTS: EP(1) and FP receptor mRNAs were highly expressed in blood vessels, muscles and the endothelia of the iris. EP(1) receptor hybridization signals were present in all muscle fibers of the ciliary body. Hybridization signal corresponding to FP receptor mRNA transcript was predominantly expressed in the circular muscle and in the collagenous connective tissues of the ciliary body. FP receptor mRNA was not detected in radial and longitudinal muscles. CONCLUSIONS: EP(1) and FP receptor mRNAs in human ocular tissues appear to be widely localized in the functional sites of the respective receptor agonists. Selective localization of EP(1) and FP receptor mRNAs in the circular muscles and collagenous connective tissues of the ciliary body suggests that EP(1) and FP receptors play an important role in enhancing uveoscleral outflow of aqueous humor.

Ciliary Body↗

PubMed2002

Late postoperative complication of the foldable lens implantation: opacification of the intraocular lenses.

OBJECTIVE: To analyze the cause of the late postoperative opacification of the lens optic of implanted intraocular lens (IOL). METHODS: Twenty-two foldable hydrophilic acrylic lenses with opacification of their optics in 19 patients were taken out of the eye by surgery and examined by gross examination and microscopy. The lenses were stained with alizarin red and von Kossa method (special stains for calcium). Some were submitted for energy dispersive X-ray spectroscopy and scanning electron microscopy. The same kind of transparent IOLs were examined as the control group. RESULTS: Granular deposits of variable sizes were revealed on the surface and within the lens optics. The deposits that were stained positive with alizarin red and von Kossa method showed the presence of calcium. Energy dispersive X-ray spectroscopy demonstrated the calcium and the phosphate present in the deposits. The distribution of the granules was dense in the central part of the optic and sparse at its periphery. There were negative findings in the haptics of the lenses taken out and the control lenses. CONCLUSION: The cause of the opacification of the foldable lens optics is the deposits that consist of calcium and phosphate occurring inside and on the surface of the optics.

Device Removal↗

PubMed2002

[A clinical study of posterior capsular opacification after implantation of foldable intraocular lenses with different edges of optics].

OBJECTIVE: To study the influence of intraocular lens (IOL) optics with a square truncated edge on the incidence of posterior capsular opacification (PCO). METHODS: This consecutive series of 140 eyes (140 cases) underwent phacoemulsification with implantation of a foldable IOL with a square truncated edges (n = 90) or a foldable IOL with a round tapered edges (n = 50). We evaluated visual acuity, overall incidence of PCO and the incidence of PCO under different continuous curvilinear capsulorrhexis (CCC) conditions after surgeries. The mean postoperative follow-up was (14 +/- 8) months (range, 6 to 48 months) and (18 +/- 8) months (range, 6 to 48 months) respectively. RESULTS: Posterior capsular opacification occurred in 8.9% (8/90 eyes) of eyes in the square truncated edge designed group and 38.0% (19/50 eyes) of eyes in the round tapered edge designed group. The difference between the 2 groups was statistically significant (P < 0.01). Moderate CCC with the diameter slightly smaller than that of the IOL optic was achieved in 76 eyes in the square truncated edge group and no PCO was found. In the round tapered edge group, moderate CCC was achieved in 41 eyes in which 10 eyes developed PCO. Amonhad a large or decentered CCC, 8 out of 14 eyes (57.1%) in the square truncated group developed PCO, and 9 out of 9 eyes (100.0%) in the round tapered group developed PCO. The difference is also significant (P < 0.05). Nd: YAG laser capsulotomy rate was lower in the square truncated edge group (1.1%) than that in the round tapered edge group (10.0%) (P < 0.05). CONCLUSION: Moderate CCC and IOL optic design with a square truncated edge are the two important factors for prevention of posterior capsular opacification.

Adult↗

PubMed2002

Effect of intracameral lidocaine anesthesia on the anterior segment of rabbit eyes.

PURPOSE: To evaluate the effect of intracameral anesthesia on the anterior segment of rabbit eyes using chinese-made lidocaine. METHOD: The study comprised eight eyes of four white rabbits which were divided into three groups according to the concentration of the lidocaine given. They are 0.5%, 1%, 2% lidocaine groups and balanced salt solution (BSS) control group. Each group contained two eyes. After 0.5 ml of the anesthetic agent was injected into the anterior chamber and retained there for ten minutes, the rabbits were executed and the eye balls were enucleated. Pathological examinations of the anterior segment, including cornea, iris and ciliary body, were carried out immediately. RESULT: The pathological study revealed no abnormal findings in lidocaine 0.5% and 1% groups compared with the control group, where as in the lidocaine 2% group, much abnormal pathological change was found, including the shrinkage of corneal endothelium, stroma edema of iris and ciliary body. CONCLUSION: Using intracameral anesthesia of high concentration of chinese-made lidocaine would run a risk of damaging the anterior segment of rabbit eye. But at the low concentration usually used in cataract surgery, no adverse effect was found.

Anesthetics, Local↗

PubMed2002

Clinical application of the sapphire unfolder lens injection system.

PURPOSE: To summarize the clinical experience of 300 cases using the Sapphire unfloder intraocular lens (IOL) injection system. METHODS: After the standard phacoemulsification, an AR40e IOL was implanted using the Sapphire Unfolder. The involved problems during and after the operation were observed and analyzed. RESULTS: The complications occurred during the operation including the crack at the haptic-optic junction in 2 cases, slight kink in the haptic in 5 cases, IOL clamp into the cartridge in 2 cases, posterior capsular rupture in 2 cases and endothelium damage in the central small area in 4 cases. All the patients recovered successfully with IOLs in good CONCLUSION: IOL implantation with the Sapphire Unfolder led to no serious complications and got the satisfactory results.

Aged↗

PubMed2002

Morphometry of axons in optic nerves of Siamese's twins.

PURPOSE: To observe the development of optic nerve, we examined four optic nerves from Siameses Twins by absolute counts of axons. METHODS: Mean axon diameter, mean axon density, totally axonal population and optic nerve area were noted for each optic nerve. The mean axon diameter and the mean axon density were compared between paraxial (inner sectors) and cortical(outer sectors) areas of the nerves. RESULTS: More myelinated axons were seen in the inner sectors as compared to the outer sectors (average 11 axons/1000 microm2 in inner sectors and 34 axons/1000 microm2 in outer sectors (P = 0.036). The myelinated fibers were also smaller (63 microns) in the outer sectors as compared to the inner sectors (72 microns) (P = 0.001). The average cross sectors area for the four 40 week stage optical nerves of Siamese Twins was 3.32 x 103 as compared to 1 million axons for 32-week-old normals. CONCLUSION: Our finding of fewer axonal number and small myelinated fibers in the Siamese Twins suggests hypoplasia. Myelination was more abnormal in the paraxial optic nerve than that in the peripheral sectors, suggesting anomalous development of optic nerve peripherally and delayed developnent centrally. Axonal density is higher in inner sectors than that in outer sectors, suggesting delayed development of the outer nerve sector.

Anthropometry↗