Biomedical subjects

Ping-I Chou

Publications and source records attributed to Ping-I Chou.

4 recordsLinked to original sources

PubMed2006

Glucosamine sulfate inhibits TNF-alpha and IFN-gamma-induced production of ICAM-1 in human retinal pigment epithelial cells in vitro.

PURPOSE: Glucosamine sulfate (GS) is a naturally occurring sugar that possesses some immunosuppressive effects in vitro and in vivo, but its mechanism is unknown. We investigated whether GS could modulate the proinflammatory cytokine-induced expression of the gene for intercellular adhesion molecule (ICAM)-1, an inflammatory protein in human retinal pigment epithelial (RPE) cells. METHODS: ARPE-19 cells were used as a model to determine the effects of GS on the expression of the ICAM-1 gene upregulated by TNF-alpha or IFN-gamma, by Western blot analysis and semiquantitative reverse transcription polymerase chain reaction (RT-PCR). The activation and nuclear translocation of the nuclear factors NF-kappaB and STAT1 were evaluated by immunocytochemistry, Western blot analysis, and electrophoretic mobility shift assay (EMSA). RESULTS: Both TNF-alpha and IFN-gamma increased the expression of ICAM-1 at the mRNA and protein levels in a time- and dose-dependent manner in ARPE-19 cells. GS effectively downregulated the TNF-alpha- or IFN-gamma-induced expression of ICAM-1 in the protein and mRNA level in a dose-dependent manner. GS further inhibited the nuclear translocation of p65 proteins in TNF-alpha and phosphorylated STAT1 in IFN-gamma-stimulated ARPE-19 cells. CONCLUSIONS: GS inhibits the expression of the ICAM-1 gene in ARPE-19 cell stimulated with TNF-alpha or IFN-gamma through blockade of NF-kappaB subunit p65 and nuclear translocation of STAT1. This study has demonstrated a potentially important property of GS in reducing ICAM-1 mediated inflammatory mechanisms in the eye.

Blotting, Western↗

PubMed2003

Contrast sensitivity after +Gz acceleration.

BACKGROUND: This study was designed to determine the extent and duration of contrast sensitivity (CS) loss after high sustained +Gz acceleration in a centrifuge. METHODS: The subjects were 12 healthy male flight surgeons between 20 and 22 (mean = 21.1) yr of age. The human centrifuge at the Aviation Physiology Research Laboratory in Tainan, Taiwan, was used to expose the subjects to an acceleration profile. Each subject experienced three centrifuge runs made up of one gradual onset and two rapid onset profiles. Contrast sensitivity (CS) was measured before, and at 5 min, 10 min, and 20 min for the right eye; and 7 min, 12 min, and 22 min for the left eye after the acceleration. Both eyes were measured with the right eye being tested first. RESULTS: There was a generalized depression of CS at 5-12 min for both eyes. The depression was more severe at low and medium frequencies (1.5, 3.0, 6.0 cycles per degree, cpd) than at a high spatial frequency (18.0 cpd). There was a significant decrease in CS of the right eye at 1.5 cpd (p < 0.05 between control and 5 min), and on the left eye at 3.0 cpd (p < 0.05 between control and 7 min, p < 0.05 between control and 12 min) and 6.0 cpd (p < 0.05 between control and 12 min). The CS loss was more obvious at 5-12 min for both eyes, and there was only partial recovery at 22 min after the acceleration. CONCLUSIONS: These results demonstrated that +Gz acceleration is associated with CS loss. The recovery time was greater than expected. Factors other than ocular blood flow may be involved in the prolonged CS loss.

Adult↗

PubMed2002

Inducible adeno-associated virus vector-delivered transgene expression in corneal endothelium.

PURPOSE: To investigate whether recombinant adeno-associated virus (rAAV) vector--mediated transgene expression is induced by inflammation in corneal endothelial cells in vivo. METHODS: The ocular anterior chamber of New Zealand White rabbits was injected with rAAV-LacZ (10(7) units of infection). Transient ocular anterior segment inflammation was induced by an intravitreal injection of lipopolysaccharide (LPS). The effect of inflammation on LacZ gene expression in corneal endothelial cells was evaluated by histochemical staining and reverse transcription-polymerase chain reaction (RT-PCR). The influence of rAAV on endothelial cell function was monitored by measuring corneal thickness. RESULTS: Inflammatory reaction peaked at 1 day after LPS treatment and, at the same time, most of the endothelial cells (91.3% plus minus 7.2%) showed prominent LacZ gene expression. The transgene expression gradually diminished to basal level (3.4% plus minus 2.1%) when the inflammation subsided at 15 days after LPS treatment. The diminished transgene expression was efficiently reactivated to a high level (86.1% plus minus 8.7%) by a second LPS injection 60 days later. Moreover, the transgene expression remained low for a long period (60 days) in the absence of LPS treatment, but was increased to high levels (87.3% plus minus 8.1%) 1 day after LPS treatment. Throughout the observation period, endothelial cell function remained intact. CONCLUSIONS: The rAAV vector can deliver genes into endothelial cells, and transgene expression is dramatically induced by inflammation. The rAAV-delivered transgene is stable and does not compromise endothelial cell function. Inducible rAAV-mediated transgene expression in corneal endothelial cells is a potential strategy in the treatment and prevention of ocular diseases.

Animals↗

PubMedDate not supplied

Effect of sympathetic denervation on rabbit choroidal blood flow.

In this study we demonstrate the existence of sympathetic innervation and compare the effect of unilateral or bilateral superior cervical sympathectomy on albino rabbit choroidal blood flow (CBF) during changes in perfusion pressure (PP). Forty albino rabbits weighing between 2.0 and 3.0 kg were randomly divided into three groups. The bilateral sympathectomy group (group S) included 10 rabbits (20 eyes) that received bilateral sympathectomy 1 week prior to the study. The unilateral sympathectomy group (group U) included 20 rabbits (20 eyes) that received unilateral sympathectomy 1 week prior to the study. Only the eyes ipsilateral to sympathectomy were utilized. The other 10 rabbits (20 eyes) served as controls (group N), each received the same procedure as the experimental groups except that the superior cervical ganglion (SCG) was preserved. The blood cell flux (PF), velocity (V), and concentration of moving blood cells (CMBC) were recorded simultaneously by means of a laser Doppler flowmeter (Perimed PF4001), while the intraocular pressure was increased linearly with a syringe pump. When the PP decreased steadily, the PF, V, and CMBC remained constant until PP <55 mm Hg, then decreased proportionally to the PP. When the PP decreased from 75 to 0 mm Hg, the PF, V and CMBC decreased from 100 to 6.87 +/- 0.97%, 8.44 +/- 0.92%, and 18.67 +/- 0.91% in group N, to 18.56 +/- 1.62%, 19.30 +/- 1.84%, and 38.02 +/- 9.10% in group U, and to 18.38 +/- 2.89%, 16.78 +/- 1.48%, and 34.58 +/- 4.42% in group S. The changes in PF, V, and CMBC were similar in groups S and U. Both group S and U had higher PF, V, and CMBC values than group N at comparable PPs below 55 mm Hg. These results indicate that the SCG plays a role in CBF regulation. Both unilateral and bilateral sympathectomy led to a higher PF in both groups S and U rabbits, indicating increased CBF while PP decreased gradually. This suggests that the rabbit choroid does not receive crossed innervation. The plateau response in each curve demonstrates the presence of autoregulation. This autoregulation was unchanged by either unilateral or bilateral sympathetic denervation.

Animals↗