Biomedical subjects

C H Chiang

Publications and source records attributed to C H Chiang.

At least 19 recordsLinked to original sources

PubMed2005

Pulmonary inflammation caused by chitosan microparticles.

Chitosan is a cationic biopolymer derived from chitin with potential therapeutic applications such as controlled drug delivery to mucosal-epithelial surfaces in the body. Inhaled chitosan microparticles (CM), for example, are of potential interest in pulmonary pharmacotherapy. In this context, we examine some basic reactions of lung tissue to CM. Inhaled CM (2-10 mg/kg of particles) induce dose-dependent proinflammatory effects in rat lungs; these effects are documented in increases in bronchoalveolar lavage fluid protein (BALF-P) and lactate dehydrogenase activity (BALF-LDH) and increases in lung tissue myeloperoxidase (MPO) activity and leukocyte migration. Overall, the biochemical parameters (i.e., average of BALF-P, BALF-DH, and MPO) indicate that the inflammation response is 1.8-fold greater than controls without CM; the same inflammation parameters, however, are 1.9-fold lower with CM compared with the proinflammatory effects of lipopolysaccharide (LPS). Cytological examination of BALF shows a large infiltration of polymorphonuclear neutrophils to lung tissue: more than a sixfold increase in this population of inflammatory cells, after inhalation of CM relative to air inhalation controls. Thus, the results indicate that inhaled CM can have significant proinflammatory effects on lung tissues; these effects are mild relative to LPS but need to be considered in the context of therapeutic applications via pulmonary delivery if such concentrations of CM are used.

Animals↗

PubMed2004

The influence of image magnification in first-trimester screening for Down syndrome by fetal nuchal translucency in Asians.

OBJECTIVE: The aim of this prospective study was to evaluate the impact of image magnification in the measurements of crown-rump length (CRL) and nuchal translucency (NT) thickness for first-trimester Down syndrome screening in Asians. METHODS: Ultrasound measurements of NT and CRL were performed in 561 consecutive Taiwanese unaffected fetuses and 11 cases of Down syndrome fetuses between 12 and 14 weeks of gestation. All sonographic images were measured by one qualified examiner to prospectively undergo first-trimester NT screening for Down syndrome. Fetal CRL and NT thickness were measured on three separated images including the original image, regular image, and the magnified image. RESULTS: A significant mean difference (0.59 +/- 4.24 mm) of CRL was found between measurements on the original and regular image (p < 0.001). There was a significant mean difference of NT thickness measurements between the regular and magnified image (0.12 +/- 0.25 mm, p < 0.001). Seven out of the 11 cases (63.6%) of Down syndrome with NT thickness > or =2.5 mm was measured on three separated images. A significantly reduced incidence of NT thickness > or =2.5 mm on the magnified image was noted than those of the original and regular image measurements in unaffected cases (p < 0.001). Either using the assessing method by the 95th centile cutoff value of NT thickness or combined risk, our results could achieve observed detection rate of 63.6% measured on three separated images. CONCLUSIONS: Our data indicate that the image magnification could reduce the false-positive rate by using a fixed cutoff value of NT thickness, but would have no influence on the results when using the assessing method either by the 95th centile cutoff value of NT thickness or the combined risk. In order to place the caliper more accurately, a magnified image should be recommended as a standard image in the measurements of the NT thickness.

Adult↗

PubMed2004

In vivo and in vitro characteristics for insulin-loaded PLA microparticles prepared by w/o/w solvent evaporation method with electrolytes in the continuous phase.

Insulin-loaded poly(lactide) (PLA) microparticles were successfully prepared by 6% w/v PLA in the organic phase, 10% w/v PVP and varied types of 5%w/v electrolytes in the continuous phase, by using a water-in-oil-in-water emulsion/ solvent extraction technique. Addition of electrolytes such as NaCl, CaCl2 into the external phase significantly improved insulin entrapment efficiency compared to the case of no additives. NaCl was the most effective for obtaining high entrapment efficiency, with microparticle yield 81.2%, trapping efficiencies 49%, insulin-loading level 5.5% w/w and mean particle size 14.8 microm. The distribution (%) of insulin on the PLA microparticles surface, outer layer and core were 8, 37 and 43%, respectively. The cumulative release of insulin had an upper limit of approximately 24% of the insulin load at 24 days. A steady release rate was 0.5 microg insulin/mg microparticles/day of insulin release maintained for 24 days. Total protein-leaking amount was reduced after addition of electrolytes in the continuous aqueous phase. Rabbit glucose levels were evaluated after subcutaneous 20 mg insulin-loaded PLA microparticles or PLA blank microparticles. Study results show that the insulin-loaded PLA microparticles significantly reduced the glucose level than PLA blank microparticles. The insulin-loaded PLA microparticles, physicochemical characterization data and the animal result obtained in this study may be relevant in optimizing the PLA microparticle formulation incorporation and delivery insulin carriers.

Animals↗

PubMed2004

The mechanism of surface-indented protein-loaded PLGA microparticle formation: the effects of salt (NaCl) on the solidification process.

The purpose of this study was to evaluate ovalbumin (OVA) leakage pathways and to explore the mechanism of the surface-indented microparticle formation in the preparation of OVA-loaded microparticles. OVA-loaded poly (D,L-lactic-co-glycolic acid) (PLGA) microparticles were prepared by a water-in oil-in water (w/o/w) solvent evaporation method associated with varied NaCl (NaCl) concentrations and adjusted with urea at 1240mOsm kg(-1) in the external aqueous phase. To evaluate dichloromethane (DCM)-related OVA leakage, three stirring rates, 600, 800, 1000rpm at 25 degrees C were carried out during the solvent evaporation stage. Both DCM and OVA levels in the external phase medium and total dispersion were sampled and measured. The time course of particle characteristics was evaluated by microscopy or SEM photography. The surface adsorptive capacities of the prepared microparticles were measured by using bovine serum albumin conjugated with fluorescein isothiocyanate (FITC-BSA). The findings were that the DCM-related OVA leakage accounted for approximately 34%, of the total leakage. By combining NaCl in the external phase, a faster solidifying crust-like structure was formed as a barrier to remarkably reduce OVA loss and improve OVA content from 40.1 to 72.8 microg mg(-1). The yield and OVA content for formulations containing NaCl were much improved by the ionic effect, in addition to the osmotic effect. The total entrapment efficiency was also highly increased from 43 to 72%. The formations of the crust-like surface structure of the microparticle were affected by entrapped drugs, salt content in the external phase and aqueous volume in the inner phase. A scheme was proposed to interpret the formation mechanism of the surface-indented microparticles. In comparison to the surface-smooth microparticles, the surface adsorptive capacities of the surface-indented microparticles were highly improved from 26.6 to 87.0%, determined by the adsorption of FITC-BSA.

Adsorption↗

PubMed2001

In vitro and in vivo evaluation of an ocular delivery system of 5-fluorouracil microspheres.

Solvent evaporation technique with O/O (oil/oil) emulsion was used to prepare 5-FU (5-fluorouracil) biodegradable microspheres with a polymer of poly(dl-lactide-co-glycolide) combining lecithin as an emulsifier. In vitro drug release was conducted in phosphate buffer with pH 7.4 at 37 degrees C. For in vivo studies, 10 mg of 5-FU microspheres (containing 1 mg of 5-FU) were implanted in the conjunctival area of the rabbit eye. Rabbits were sacrificed at certain time intervals within 7 days after drug application. Samples of aqueous humor and sclera were prepared and analyzed by the high performance liquid chromatography (HPLC) method. The tested 5-FU microsphere contained 10% drug with a mean particle size of 4.4 +/- 0.6 microm. The microsphere had a burst release initially (64.9 +/- 1.5%), followed by a sustained release; the cumulative release at time points of 1, 10 and 21 days were 71.9 +/- 1.9%, 80.1 +/- 2.1% and 89.8 +/- 2.3%, respectively. For in vivo studies, aqueous humor levels showed a peak at the first sampling point (2 hr), then maintained low levels of 5-FU with a range 0.2-1 microg/mL. Scleral levels were 20-80 microg/mL during a 7-day study. Our results indicate that the prepared 5-FU microsphere provided a long-term release for more than 1 week. The preparation showed no irritation and low toxicity (< 100 microg/mL). For application to the eye, it might be potentially useful as a complement drug system in glaucoma filtration surgery.

Animals↗

PubMed2001

Protective effect of lipophilic antioxidants on phorbol-induced acute lung injury in rats.

OBJECTIVE: To determine whether the lipophilic antioxidant U-74389G can ameliorate the acute lung injury induced by phorbol myristate acetate (PMA) in our isolated lung model in rats, and to compare its activity with the intracellular enzymes superoxide dismutase (SOD) or catalase. DESIGN: Randomized, controlled study. SETTING: Animal-care facility procedure room. SUBJECTS: Forty-two adult male Sprague-Dawley rats each weighing 250-350 g. INTERVENTIONS: Typical acute lung injury was induced successfully by PMA during 60 mins of observation. PMA (2 microg/kg) elicited a significant increase in microvascular permeability (measured by using the capillary filtration coefficient Kfc), lung weight gain, the lung weight/body weight ratio, pulmonary arterial pressure, and the protein concentration of the bronchoalveolar lavage fluid. MEASUREMENTS AND MAIN RESULTS: Pretreatment with 1 mg of U-74389G significantly attenuated the acute lung injury induced by PMA, all parameters having decreased significantly (p <.001). The protective effect of U-74389G was dose dependent, but SOD (6,000 U/kg) or catalase (50,000 U/kg) exhibited no protective effect. CONCLUSIONS: U-74389G significantly ameliorates acute lung injury induced by PMA in rats.

Animals↗

PubMed2001

Comparison of effectiveness of intracellular and extracellular preservation solution on attenuation in ischemic-reperfusion lung injury in rats.

BACKGROUND: Human lung allografts can only be preserved for 6 hours. Experimental interventions that reduce ischemia-reperfusion (I/R) lung injury can be used to improve the properties of the preservation solution. The best solution for lung preservation is still a matter of controversy. The purpose of this study was to compare the protective effects of various solutions on I/R lung injury in Sprague-Dawley rats. METHODS: The following solutions were compared: a physiological salt solution; an intracellular preservation solution (the University of Wisconsin Solution, UW); an extracellular preservation solution (EP3); and the extracellular preservation solution with the addition of various protective agents--EP3 plus dexamethasone (Dex) (EP3-a), plus glutathione (GLU) and allopurinol (ALL) (EP3-b), and EP3 plus GLU, ALL, lactobionate (LACT), and raffinose (RAF) (EP3-c). I/R lung injury was induced by ischemia for either 45 or 60 minutes, followed by reperfusion for 60 minutes. Hemodynamic changes, lung weight gain (LWG), and capillary filtration coefficients were measured. RESULTS: Both EP3 and UW preservation solutions had partial attenuation effects on I/R lung injury, but UW produced a better attenuation effect than EP3. Use of modified EP3 solutions containing either protective agents (GLU, ALL, or Dex) or impermeants (LACT and RAF) improved the ability of EP3 to reduce I/R lung injury. The LWG using the modified EP3-c solution was the lowest among all groups. UW induced pulmonary hypertension. After I/R challenge, pulmonary arterial pressure with EP3-c was lower than with UW. Based on a lower LWG and the changes in hemodynamics, EP3-c is a better lung preservation solution than UW and EP3. CONCLUSIONS: Based on the attenuation of I/R injury, we conclude that there is no significant difference between intracellular UW and extracellular (EP3-a, EP3-b) preservation solutions in this rat model, but the addition of protective agents and impermeants to the solution are important. The findings suggest that EP3-c might be a better lung preservation solution than UW.

Adenosine↗

PubMed2001

Cytokine up-regulation in ischaemic/reperfused lungs perfused with University of Wisconsin solution and normal saline.

Ischaemia/reperfusion (I/R) lung injury using University of Wisconsin solution (UW) as perfusate has not been well studied. Isolated rat lungs were challenged with various periods of ischaemia and/or reperfusion. Haemodynamics, lung weight gain (LWG), capillary filtration coefficient (K(fc)), tissue pathology, the concentrations of cytokines in the perfusate, and mRNAs for the various cytokines in the lung tissues were measured. I/R induced a permeability type of pulmonary oedema, as reflected by increases in LWG and K(fc). LWG and K(fc) in the I(45)R(60)(UW) group (45 min of ischaemia followed by 60 min of reperfusion with UW) were only 2% and 5% respectively of those in the I(45)R(60)(NS) group (where NS is normal saline). LWG and K(fc) in the UW group had both increased by 180 min, to values similar to those in the I(45)R(60)(NS) group. However, these findings show that UW was remarkably effective at preventing LWG after 60 min of reperfusion, and was more than 3-fold more effective than NS in delaying LWG. For longer ischaemic times only, or the same period of ischaemia followed by longer reperfusion periods, greater lung injury occurred. I/R lung injury also induced increased concentrations of tumour necrosis factor-alpha (TNF-alpha), interleukin 1 and interleukin 6 in the perfusate, and increased the mRNAs for these cytokines in lung tissue. A significant correlation was obtained between TNF-alpha concentration and LWG. TNF-alpha production in the I(45)R(60)(UW) group was only 7% of that in the I(45)R(60)(NS) group. However, TNF-alpha mRNA expression in the I(45)R(60)(UW) group was 80% of that in the I(45)R(60)(NS) group. This indicates that transcription/translation do not correlate well with cytokine production, and also suggests that one reason for the effectiveness of UW in delaying LWG may be because it delays TNF-alpha production. In summary, ischaemia or I/R caused a permeability-type pulmonary oedema that was associated with leucocyte infiltration and the up-regulation of various cytokines, regardless of the perfusion fluid. Except for pulmonary hypertension, less severe I/R lung injury and delayed cytokine production in lungs perfused with UW, the pattern of injury associated with I/R challenge was similar to that in lungs perfused with NS. We propose that more or long-acting protective agents are required as additives in order to modify UW to produce an optimal preservation solution.

Adenosine↗

PubMed2001

Psychometric assessment of the Chinese language version of the St. George's Respiratory Questionnaire in Taiwanese patients with bronchial asthma.

BACKGROUND AND PURPOSE: The St. George's Respiratory Questionnaire (SGRQ) is a disease-specific quality-of-life instrument. It was designed to measure quality of life in obstructive pulmonary disease, and its reliability and validity have been demonstrated in different language versions. The purpose of this study was to determine the psychometric properties of a Chinese language version of the SGRQ in Taiwanese asthma patients. METHODS: A convenient sample of 124 asthma patients were recruited from the outpatient asthma clinic of a teaching hospital in the Taipei area. The inclusion criteria were outpatient, coherent, and a clinical diagnosis of asthma. Patients with additional medical conditions considered to impact the quality of life were excluded. Three component scores (symptoms, activity, and impacts) and a total score were calculated to assess the SGRQ's psychometric characteristics. Data including demographic characteristics, history of emergency visits and hospital admissions, asthma severity, and quality of life were collected by questionnaires. Cronbach's formula for the alpha-coefficient was used to estimate the internal consistency and reliability of the SGRQ. Pearson's product-moment correlation was used to estimate the concurrent validity of the SGRQ. The discriminating validity of the SGRQ was determined by the t-test for independent samples. RESULTS: Results showed that the SGRQ was internally consistent, and had good content and face validity. The SGRQ total score was significantly correlated with both the Health Index and the RAND 36-item Health Survey (p < 0.05). The SGRQ discriminated patients with respect to asthma severity (p < 0.001), history of prior emergency visits (p < 0.05), and history of prior hospital admissions (p < 0.05). CONCLUSIONS: This study demonstrated that the Chinese language version of the SGRQ has internal consistency and validity with strong evidence of content, concurrent, and discriminating validity in Taiwanese asthma patients. These findings suggest that it is a useful measure of quality of life in Taiwanese asthma patients.

Adolescent↗

PubMed2000

Acyclovir-containing liposomes for potential ocular delivery. Corneal penetration and absorption.

The in vitro corneal penetration and in vivo corneal absorption of acyclovir from an acyclovir-containing liposome system were investigated. Results of in vitro corneal penetration demonstrated that positively charged liposomes resulted in a penetration rate lower than those of negatively charged liposomes and free acyclovir in solution. An in vivo study indicated that the extent of acyclovir absorption from positively charged liposomes was higher that those from negatively charged liposomes and free acyclovir. The acyclovir concentration in the cornea after administration of positively charged liposomes showed that an acyclovir deposition in the cornea was greater than those of negatively charged liposomes and free acyclovir. From morphological observation of the cornea surface treated with liposomes, it was suggested that positively charged liposomes formed a completely coated layer on the cornea surface. These liposomes would bind intimately on the cornea surface, leading to an increase of residence time. Therefore, positively charged liposomes resulted in an increase of acyclovir (ACV) absorption.

Absorption↗

PubMed2000

Development of perceptual asymmetry for free viewing of chimeric stimuli.

Free-viewing chimeric stimuli tasks have been used in a number of studies to assess perceptual asymmetries and draw inferences about hemispheric lateralization in children and adults. In order to determine whether perceptual asymmetries for nonverbal information are present in children, a free-viewing chimeric stimuli task was used in 63 normally developing 6- through 16-year-old children. Stimuli included affect (happy faces), gender, quantity, and shape. An overall left hemispace (LHS) advantage was present by 6 years of age. This LHS preference was more prominent by age 10 and then plateaued. No preference for shape was detected at any of the age ranges studied. These results suggest that perceptual asymmetries for visual stimuli develop during childhood and appear to reach a plateau by age 10. The observed specificity for certain types of nonverbal stimuli should be taken into account in future studies of perceptual asymmetry in both normal and neurologically impaired children.

Adolescent↗

PubMed2000

Spleen laceration, a rare complication of laparoscopy.

A 31-year-old woman had secondary infertility of 4 years' duration. Hysterosalpingography revealed bilateral distal tubal occlusion with bilateral hydrosalpinx-like appearance. At laparoscopy, both oviducts were occluded with marked hydropic change. Salpingoplasty was performed to correct bilateral hydrosalpinges and reform the fimbriated tubal ends. The procedure was performed uneventfully by an experienced surgeon in 45 minutes. Nine hours after the operation an emergency exploratory laparotomy was performed due to massive intraabdominal bleeding. The cause was a small tear, 3 cm long and 1 cm deep, with active bleeding in the inferior splenic tail. The laceration was repaired successfully with 1-0 chromic suture. The etiology of splenic laceration during laparoscopic surgery is uncertain. Many complications of laparoscopy are physiologic, and this one might have occurred while establishing pneumoperitoneum. Distortion and stretching of small vascular adhesions of the spleen with the abdominal wall also may have played a role. Gynecologists must be aware of the physiologic insult to patients during laparoscopy.

Adult↗

PubMed2000

Prediction of pregnancy rate of in vitro fertilization and embryo transfer in women aged 40 and over with basal uterine artery pulsatility index.

PURPOSE: The purpose was to determine the effect of basal uterine perfusion on the pregnancy rates of in vitro fertilization and embryo transfer (IVF-ET) in women aged 40 and above. METHODS: A total of 47 patient aged 40 and over underwent IVF-ET. The conception cycles and the nonconception cycles were compared. RESULTS: Of the 47 patients, 4 patients were pregnant (8.5%). The mean age, basal follicle stimulating hormone (FSH), basal estradiol (E2) level, antral follicle count (AFC), number of ampoules of gonadotropin used, E2 levels and endometrial thickness on the day of human chorionic gonadotropin (hCG) administration, number of retrieved and fertilized oocytes, and number of transferred embryos were not statistically significant between the conception and nonconception cycles. However, the basal uterine artery pulsatility index (UA PI) was significantly lower in the conception cycles (P < 0.001). The receiver operating characteristics (ROC) curve analysis for basal FSH, AFC, and basal UA PI in predicting the pregnancy rate of IVF in patients aged > or = 40 were demonstrated. The best prediction rate was achieved by a pulsatility index cutoff of < 2.0 for a receptive uterus. CONCLUSIONS: Increased uterine perfusion in the early follicular phase enhanced the pregnancy rate of IVF in women aged 40 and above. It is therefore essential that patients aged > or = 40 with poor basal uterine perfusion should be identified early in the early follicular phase of the menstrual cycle to apply appropriate intervention to improve the uterine circulation for the subsequent chance of pregnancy.

Adult↗

PubMed2000

Anaerobic stability of aqueous physostigmine solution.

The anaerobic stability of physostigmine was studied in this report. Physostigmine and two important degradants, eseroline and rubreserine, were identified by a high-performance liquid chromatography (HPLC) system using a photodiode array detector and a UV detector at the retention times of 12.4, 9.2, and 7.9 min. Under anaerobic treatment, the minimum degradation rate constant was found at pH 3.4, evaluating from pH-rate profiles at 45 degrees C, 55 degrees C, and 70 degrees C with the pH range 2.4-6.8. The degradation of physostigmine was suggested as specific acid-base catalysis. Anaerobic activation energies of KH, K(OH), and Kobs were 9.4, 8.3, and 17.9 kcal/mol, respectively. The ratios of observed aerobic and anaerobic rate constants were 2-33 at 88 degrees C, which had a trend to increase ratios as pH increased in the range 2.4-5.2. The shelf life of physostigmine solution was estimated to be 4 years at room temperature under anaerobic conditions at pH 3.4.

Anaerobiosis↗

PubMed2000

The application of water drinking test on the evaluation of trabeculectomy patency.

The water drinking test (WDT) was once frequently used as a diagnostic tool for glaucoma, but not so often nowadays. In this study, we investigated the potential use of the WDT on the evaluation of trabeculectomy patency. Twenty age-matched volunteers and thirty-six glaucoma patients who were to receive trabeculectomy procedure were enrolled in this study. The WDT was given to the volunteers once and to all glaucoma patients before undergoing trabeculectomy and at certain intervals after the procedure. The WDT was performed in a standard manner. We defined four parameters after performing the WDT: Initial Pressure [IP, intraocular pressure (IOP) level before the WDT]; Slope of Ascending Trend (SOAT, the slope between baseline IOP and the highest IOP level); Peak Pressure (PP, the highest IOP level during the WDT); and End Pressure (EP, the IOP level after the WDT). It was found that the results of the WDT and trabeculectomy patency were strongly correlated. The four parameters in success and failure cases were significantly different at the last follow up: IP: (15.2 +/- 3.6 vs. 25.3 +/- 6.4, p<0.01); SOAT: (0.9 +/- 0.3 vs. 1.8 +/- 1.2, p<0.01); PP: (19.2 +/- 6.4 vs. 39.5 +/- 12.2, p<0.01); EP: (15.5 +/- 4.8 vs. 29.4 +/- 8.2, p<0.01). Thus, it was observed in this study that WDT was not only easy and safe to perform, but also valuable in evaluating the patency of trabeculectomy.

Adult↗

PubMed2000

Aqueous humor nitric oxide levels differ in patients with different types of glaucoma.

Nitric oxide (NO) has effects on the regulation of aqueous humor dynamics, but the exact mechanism is not yet established. To investigate the possible roles of NO in glaucoma, we determined NO levels in aqueous humor and plasma in glaucoma patients and a control group, cataract patients. The study is an open trial with purposed sampling. One hundred fifty-two patients, including 87 glaucoma patients and 65 cataract patients from two medical centers, were recruited. NO levels in the samples were measured by a chemiluminescence assay. We found that, although the mean aqueous humor NO level (mean +/- SEM) was higher in the glaucoma patients than in the cataract patients (39.7 +/- 1.5 microM vs. 35.5 +/- 1.3 microM, p < 0.05), NO levels varied significantly in different types of glaucoma. The juvenile glaucoma patients had the lowest mean NO level (8.4 +/- 0.9 microM), while the acute angle-closure glaucoma and neovascular glaucoma patients had the highest mean NO levels (64.8 +/- 7.6 microM, 67.3 +/- 8.2 microM). In comparison, the mean plasma NO level in the glaucoma patients was not statistically different from that in the cataract patients (14.1 +/- 1.2 microM vs. 13.9 +/- 1.1 microM, p = 0.91). Our data may provide information for applying NO-mimicking nitrovasodilators in the treatment of glaucoma.

Aged↗

PubMed2000

Wound modulation after trabeculectomy by different formulations of antimetabolites in rabbits.

A prospective, randomized study was performed to examine the effects of subconjunctival retention of 5-fluorouracil (5-FU) microparticles or 5-FU microparticles combined with mitomycin-C (MMC) on the success of trabeculectomy procedure in 32 New Zealand white rabbits. Drug-loaded microparticles were prepared using a biodegradable polymer, 50:50 ploy (D,L-lactide-co-glycolide) (50:50, PLG, MW 9000), by an oil-in-oil emulsification/solvent extraction technique. Each rabbit underwent trabeculectomy on both eyes, then one of the 5-FU and/or MMC preparations was placed at the site of the filtering surgery intraoperatively in the right eye, while the left eye was used as a control. The rabbits were randomly allocated to one of four treatment groups: group 1 rabbits received 5% 5-FU microparticles 10 mg; group 2 rabbits received 10% 5-FU microparticles 10 mg; group 3 rabbits received 10% 5-FU microparticles 5 mg and MMC 0.01 mg (5-FU/MMC); and group 4 rabbits received MMC 0.02 mg. Postoperatively, intraocularpressure (IOP), bleb survival, complications and IOP dynamics were compared during a follow-up period of 42 days. The results showed that IOPs were significantly lower in the eyes that received groups 3 and 4 treatments, while the eyes that received low concentrations of 5-FU microparticles resulted in no difference in IOPs as compared with those of controls. At 42 days, blebs were present in 100% of the eyes treated with 5-FU/MMC and MMC, but 0% of the eyes treated with 5-FU microparticles. The blebs in the eyes treated with MMC 0.02 mg were thinner, and significant complications (endophthalmitis, transient corneal opacification and neovascularization) occurred. In addition, the IOP dynamics study revealed that the eyes treated with 5-FU/MMC and MMC resulted in less IOP spikings after intravenous infusion of 0.9% NaCl solution. Our study suggested that the use of 5-FU microparticles in promoting the success of trabeculectomy in rabbits is dose-dependent, and its effect is less potent than a single intraoperative application of MMC.

Animals↗

PubMed2000

Hormonal regulation of estrogen receptor alpha and beta gene expression in human granulosa-luteal cells in vitro.

Estrogen is one of the major sex steroid hormones that is produced from the human ovary, and its actions are established to be a receptor-mediated process. Despite the demonstration of estrogen receptor (ER) expression, little is known regarding the regulation of ER in the human ovary. In the present study we investigated the expression and hormonal regulation of ERalpha and ERbeta in human granulosa-luteal cells (hGLCs). Using RT-PCR amplification, both ERalpha and ERbeta messenger ribonucleic acid (mRNA) were detected from hGLCs. Northern blot analysis revealed that ERalpha is expressed at a relatively lower level than ERbeta. Basal expression studies indicated that ERalpha mRNA levels remain unchanged, whereas ERbeta mRNA levels increased with time in culture in vitro, suggesting that ERbeta is likely to play a dynamic role in mediating estrogen action in hGLCs. The regulation of ERalpha and ERbeta expression by hCG was examined. hCG treatment (10 IU/mL) significantly attenuated the ERalpha (45%; P < 0.01) and ERbeta (40%; P < 0.01) mRNA levels. The hCG-induced decrease in ERalpha and ERbeta expression was mimicked by 8-bromo-cAMP (1 mmol/L) and forskolin (10 micromol/L) treatment. Additional studies using a specific protein kinase A (PKA) inhibitor (adenosine 3',5'-cyclic monophosphorothioate, Rp-isomer, triethylammonium salt) and an adenylate cyclase inhibitor (SQ 22536) further implicated the involvement of the cAMP/PKA signaling pathway in hCG action in these cells. The hCG-induced decrease in ERalpha and ERbeta mRNA levels was prevented in the presence of these inhibitors. Next, the effect of GnRH on ER expression was studied. Sixty-eight percent (P < 0.001) and 60% (P < 0.001) decreases in ERalpha and ERbeta mRNA levels, respectively, were observed after treatment with 0.1 micromol/L GnRH agonist (GnRHa). Pretreatment of the cells with a protein kinase C (PKC) inhibitor (GF109203X) completely reversed the GnRHa-induced down-regulation of ERalpha and ERbeta expression, suggesting the involvement of PKC in GnRH signal transduction in hGLCs. In agreement with the semiquantitative RT-PCR results, Western blot analysis detected a decrease in ERalpha and ERbeta proteins levels in hGLCs after treatment with hCG (10 IU/mL), GnRH (0.1 micromol/L), 8-bromo-cAMP (1 mmol/L), forskolin (10 micromol/L), or phorbol 12-myristate 13 acetate (10 micromol/L). Functionally, we demonstrated an inhibition of progesterone production in hGLCs in vitro by 17beta-estradiol, and this inhibitory effect was eliminated by pretreatment of 10 IU/mL hCG or 0.1 micromol/L GnRHa for 24 h before 17beta-estradiol administration. In summary, we observed a differential expression of ERalpha and ERbeta mRNA in hGLCs in vitro. The demonstration of hCG- and GnRHa-induced down-regulation of ERalpha and ERbeta gene expression suggests that hCG and GnRH may contribute to the control of granulosa-luteal cell function. Furthermore, our data suggest that the effects of hCG and GnRH on ERalpha and ERbeta expression in hGLCs are mediated in part by activation of PKA and PKC signaling pathways, respectively.

8-Bromo Cyclic Adenosine Monophosphate↗