Morphological and cytological changes of meibomian glands in patients with type 2 diabetes mellitus.

AIM: To observe the changes of microcellular structure of meibomian glands (MGs) in type 2 diabetes mellitus (DM), and to explore its correlation with the duration of diabetes. METHODS: The study assessed 132 eyes of 132 patients with type 2 diabetes mellitus (DM group) and 100 eyes of 100 non-diabetic participants (NDM group). All patients underwent the examination of the Keratograph 5M system to obtain the meibography which were used to evaluate the structure dropout of the MGs. And then laser scanning confocal microscopy (LSCM) was performed for observing the acinar cells and ducts of the MGs to obtain the following parameters: the MG acinar unit density (MGAUD), MG acinar longest diameter (MGALD) and MG acinar shortest diameter (MGASD). The examination results of the right eye were selected for analysis. RESULTS: Compared with that in NDM group, the meiboscore was significantly higher (Z=-4.057, P<0.001), and there were more MGs dropout in DM group. With the prolongation of the course of diabetes, the absence of MGs aggravated and the MGs dropout score increased (r=0.596; P<0.001). LSCM showed that there were various cytological alterations in acinar cells of MGs with the progress of diabetes duration, such as expansion, atrophy or fibrosis of MG acinar units, decreased density of MG acinar units, deposition of lipid substances, infiltration of inflammatory cells, proliferation of fibrous tissues, etc. And the opening of the glandular duct changed from smooth at the beginning to narrow, blocked, fibrotic and so on. Compared with that in NDM group, the MGAUD in DM group was significantly lower (Z=-9.713; P<0.001), the MGALD and MGASD were significantly larger (Z=-9.751, -6.416; P<0.001). With the duration of diabetes, the MGAUD reduced, the MGASD increased (r=0.860, 0.364, P<0.001); but the MGALD had no correlation with diabetic duration (r=0.133, P=0.151). CONCLUSION: With the progress of diabetes, the meibomian glandular acinar cells of diabetic patients show various manifestations. Those changes may result in the dysfuction of the MGs, tear film instability and dry eye symptoms in patients with type 2 DM.

Phacoemulsification in the anterior chamber: An alternative surgical technique in post-vitrectomy cataract.

OBJECTIVE: To evaluate the characteristics, safety and effectiveness of a modified technique of phacoemulsification in post-vitrectomy cataracts. METHODS: This retrospective clinical trial comprised 31 patients (31 eyes) with post-vitrectomy cataract, who had undergone phacoemulsification combined with intraocular lens implantation. An alternative surgical technique known as phacoemulsification in the anterior chamber was used for nucleus management in those cases. The following parameters were evaluated: best corrected visual acuity (BCVA), ocular inflammation, intraocular pressure, endothelial cell count and surgical complications. RESULTS: Three months after surgery, the BCVA improved significantly compared with that before surgery (Z=-10.547; p<0.05). There were no significant differences in IOP before and after surgery (Z=-0.474; p>0.05). There was a statistically significant postoperative decrease in endothelial cell densities (Z=-3.916; p<0.05). The mean endothelial cell loss was -8.71%. A little inflammatory response in the anterior chamber in 11 eyes and mild corneal edema in 8 eyes were observed on the first day after surgery, which subsided after a week. The posterior capsular opacification were observed in three eyes, two of which were denser, and the YAG laser was performed for posterior capsular incision. No obvious surgical complications occurred. CONCLUSION: The modified technique of phacoemulsification, with phacoemulsification in the anterior chamber, is safe and effective to deal with post-vitrectomy cataracts.

GABAAα1 and GABAAρ1 subunits are expressed in cultured human RPE cells and GABAA receptor agents modify the intracellular calcium concentration.

PURPOSE: Gamma-aminobutyric acid A (GABAA) receptors (GABAARs), which are ionotropic receptors involving chloride channels, have been identified in various neural (e.g., mouse retinal ganglion cells) and nonneural cells (e.g., mouse lens epithelial cells) regulating the intracellular calcium concentration ([Ca(2+)]i). GABAAR ß-subunit protein has been isolated in the cultured human and rat RPE, and GABAAα1 and GABAAρ1 mRNAs and proteins are present in the chick RPE. The purpose of this study was to investigate the expression of GABAAα1 and GABAAρ1, two important subunits in forming functional GABAARs, in the cultured human RPE, and further to explore whether altering receptor activation modifies [Ca(2+)]i. METHODS: Human RPE cells were separately cultured from five donor eye cups. Real-time PCR, western blots, and immunofluorescence were used to test for GABAAα1 and GABAAρ1 mRNAs and proteins. The effects of the GABAAR agonist muscimol, antagonist picrotoxin, or the specific GABAAρ antagonist 1,2,5,6-tetrahydropyridin-4-yl) methylphosphinic acid (TPMPA) on [Ca(2+)]i in cultured human RPE were demonstrated using Fluo3-AM. RESULTS: Both GABAAα1 and GABAAρ1 mRNAs and proteins were identified in cultured human RPE cells; antibody staining was mainly localized to the cell membrane and was also present in the cytoplasm but not in the nucleus. Muscimol (100 µM) caused a transient increase of the [Ca(2+)]i in RPE cells regardless of whether Ca(2+) was added to the buffer. Muscimol-induced increases in the [Ca(2+)]i were inhibited by pretreatment with picrotoxin (300 µM) or TPMPA (500 µM). CONCLUSIONS: GABAAα1 and GABAAρ1 are expressed in cultured human RPE cells, and GABAA agents can modify [Ca(2+)]i.

GABAB receptor antagonist CGP46381 inhibits form-deprivation myopia development in guinea pigs.

The aim was to investigate the effects of the GABAB receptor antagonist, CGP46381, on form-deprivation myopia (FDM) in guinea pigs. Twenty-four guinea pigs had monocular visual deprivation induced using a diffuser for 11 days (day 14 to 25). The deprived eyes were treated with daily subconjunctival injections (100 µl) of either 2% CGP46381, 0.2% CGP46381, or saline or received no injection. The fellow eyes were left untreated. Another six animals received no treatment. At the start and end of the treatment period, ocular refractions were measured using retinoscopy and vitreous chamber depth (VCD) and axial length (AL) using A-scan ultrasound. All of the deprived eyes developed relative myopia (treated versus untreated eyes, P < 0.05). The amount of myopia was significantly affected by the drug treatment (one-way ANOVA, P < 0.0001). The highest dose tested, 2% CGP46381, significantly inhibited myopia development compared to saline (2% CGP46381: -1.08 ± 0.40 D, saline: -4.33 ± 0.67 D, P < 0.01). The majority of these effects were due to less AL (2% CGP46381: 0.03 ± 0.01 mm, saline: 0.13 ± 0.02 mm, P < 0.01) and VCD (2% CGP46381: 0.02 ± 0.01 mm, saline: 0.08 ± 0.01 mm, P < 0.01) elongation. The lower dose tested, 0.2% CGP46381, did not significantly inhibit FDM (P > 0.05). Subconjunctival injections of CGP46381 inhibit FDM development in guinea pigs in a dose-dependent manner.

Inhibition of form-deprivation myopia by a GABAAOr receptor antagonist, (1,2,5,6-tetrahydropyridin-4-yl) methylphosphinic acid (TPMPA), in guinea pigs.

PURPOSE: To investigate the effects of the relatively selective GABAAOr receptor antagonist (1,2,5,6-tetrahydropyridin-4-yl) methylphosphinic acid (TPMPA) on form-deprivation myopia (FDM) in guinea pigs. METHODS: A diffuser was applied monocularly to 30 guinea pigs from day 10 to 21. The animals were randomized to one of five treatment groups. The deprived eye received daily sub-conjunctival injections of 100 µl TPMPA at a concentration of (i) 0.03 %, ( ii) 0.3 %, or (iii) 1 %, a fourth group (iv) received saline injections, and another (v) no injections. The fellow eye was left untreated. An additional group received no treatment to either eye. Prior to and at the end of the treatment period, refraction and ocular biometry were performed. RESULTS: Visual deprivation produced relative myopia in all groups (treated versus untreated eyes, P < 0.05). The amount of myopia was significantly affected by the drug treatment (one-way ANOVA, P < 0.0001); myopia was less in deprived eyes receiving either 0.3 % or 1 % TPMPA (saline = -4.38 ± 0.57D, 0.3 % TPMPA = -3.00 ± 0.48D, P < 0.01; 1 % TPMPA = -0.88 ± 0.51D, P < 0.001). The degree of axial elongation was correspondingly less (saline = 0.13 ± 0.02 mm, 0.3 % TPMPA = 0.09 ± 0.01 mm, P < 0.01, 1 % TPMPA = 0.02 ± 0.01 mm, P < 0.001) as was the VC elongation (saline = 0.08 ± 0.01 mm, 0.3 % TPMPA = 0.05 ± 0.01 mm, P < 0.01, 1 % TPMPA = 0.01 ± 0.01 mm; P < 0.001). ACD and LT were not affected (one-way ANOVA, P > 0.05). One percent TPMPA was more effective at inhibiting myopia than 0.3 % (P < 0.01), and 0.03 % did not appreciably inhibit the myopia (0.03 % TPMPA versus saline, P > 0.05). CONCLUSIONS: Sub-conjunctival injections of TPMPA inhibit FDM in guinea pig models in a dose-dependent manner.

Identification of impurities and statistical classification of methamphetamine hydrochloride drugs seized in China.

A total of 48 methamphetamine hydrochloride samples from eight seizures were analyzed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography with a flame ionization detector (GC-FID). Major impurities detected include 1,2-dimethyl-3-phenylaziridine, ephedrine/pseudoephedrine, 1,3-dimethyl-2-phenylnaphthalene, 1-benzyl-3-methylnaphthalene. These data are suggestive of ephedrine/pseudoephedrine as the main precursor of the methamphetamine hydrochloride samples seized during 2006-2007. Additionally the presence of 1,3-dimethyl-2-phenylnaphthalene, 1-benzyl-3-methylnaphthalene is indicative that six seizures were synthesized via the more specific ephedrine/hydriodic acid/red phosphorus method. In addition, five impurities were found for the first time in methamphetamine hydrochloride samples. Seventeen impurity peaks were selected from the GC-FID chromatograms. The peak areas of the selected peaks were then grouped for cluster analysis.