[Observation and quantification of diabetic keratopathy in type 2 diabetes patients using in vivo laser confocal microscopy].

Objective: To study the diabetic keratopathy in type 2 diabetes patients with retinopathy by in vivo laser confocal microscopy. Methods: This was a case-control study. Ninety type 2 diabetes patients were involved in this study from May 2015 to December 2019 in Qingdao Eye Hospital. According to the diabetic retinopathy clinical stage, these patients were divided into the non-proliferative diabetic retinopathy (NPDR) group (30 cases), early stage proliferative diabetic retinopathy (PDR) group (30 cases) and intermediate to late stage PDR group (30 cases). Thirty non-diabetic healthy volunteers were included in the control group. The central cornea was observed with an in vivo laser confocal microscope. The corneal nerve fiber density, nerve fiber length, nerve branch density, and nerve fiber tortuosity were compared between groups. The corneal Langerhans cells, epithelial cells, stromal cells and endothelial cells were also compared. Results: There were more nerve fibers and branches in the control group than the other three diabetic groups. The nerve fiber length in the control group, NPDR group, early stage PDR group and intermediate to late stage PDR group was (21.55±2.57), (14.73±1.56), (11.23±1.40) and (8.02±1.33) mm/mm2, respectively, and there were statistically significant differences between the groups (F=316.17, P=0.00). In the nerve fiber density, nerve branch density and curvature, there were statistically significant differences between the groups (F=345.72, 479.46, 167.00, all P=0.00). The basal cell density in the control group, NPDR group, and two PDR groups was (5 761±303), (5 336±367), (4 146±379) and (3 658±365) cells/mm2, respectively, and there were statistically significant differences between the groups (F=234.94, P=0.00). The anterior stromal cell density in the four groups was (836±30), (727±57), (544±59) and (360±47) cells/mm2, respectively, and there were statistically significant differences between the groups (F=535.08, P=0.00). The hexagonal endothelium cell rate in the four groups was 62.0%±5.5%, 51.1%±3.7%, 40.2%±4.0% and 27.8%±3.9%, respectively, and the Langerhans cell density was (1.5±0.6), (4.2±1.3), (6.8±2.1) and (10.9±2.1) cells/mm2, respectively; there were statistically significant differences between the groups (F=342.28, 179.78, all P=0.00). There was no statistically significant difference between the groups in the corneal endothelial cell density (F=1.58, P=0.20). Conclusions: In type 2 diabetes patients with diabetic retinopathy, the corneal nerve fiber and branch density can be significantly reduced, and the density of the hexagonal corneal endothelial cells, epithelial basal cells and anterior stromal cells can also decrease. Langerhans cells may be involved in the development diabetic keratopathy. (Chin J Ophthalmol, 2020, 56: 754-760).

Decomposition Kinetics of Omethoate in Blood.

OBJECTIVES: To study the decomposition kinetics of omethoate in blood. METHODS: The acetonitrile precipitated protein was added into the blood, with the chromatographic column of a Waters BEH C18 column （2.1 mm×50 mm, 1.7 µm）, the mobile phase of 5 mmol/L ammonium acetate aqueous solution-methanol, and the gradient elution with a flow rate of 0.3 mL/min and injection volume of 2 µL. With electrospray ionization （ESI） source and positive ion detection, qualitative and quantitative analyses were taken using multi-reaction monitoring mode. Omethoate standard was added into blank human blood to the mass concentrations of 0.78, 1.40, 2.30, 4.50, and 7.20 µg/mL, and each mass concentration was preserved at 3 temperatures of -20 ℃, 4 ℃, and 20 ℃, respectively. The content of omethoate was detected at different time points （0, 1, 3, 4, 7, 11, 15, 24, 32, 40, 48, 64, 80, 96, and 120 d）. RESULTS: Different concentrations of omethoate all showed a descended trend in human blood under different temperature conditions. The decomposition in storage environment of -20 ℃, 4 ℃, and 20 ℃ was fit to a one-compartment open model with a first-order kinetic process, which could be expressed as Ct=Coe-αt, with the calculated theoretical values of omethoate concentration close to the measured values. CONCLUSIONS: All concentrations of omethoate are decomposed in the blood, which vary a lot in different preservation conditions. It is suggested that blood samples should be frozen and detected timely in suspected omethoate poisoning cases.