Acute glycemic changes in brain and subcutaneous tissue measured by continuous glucose monitoring system in hereditary hypertriglyceridemic rat.

Parallel glucose measurements in blood and other different tissues give us knowledge about dynamics of glycemia changes, which depend on vascularization, distribution space and local utilization by tissues. Such information is important for the understanding of glucose homeostasis and regulation. The aim of our study was to determine the time-lag between blood, brain, and adipose tissue during rapid glucose changes in a male hHTG rat (n=15). The CGMS sensor Guardian RT (Minimed/Medtronic, USA) was inserted into the brain and into the abdominal subcutaneous tissue. Fixed insulin and variable rate of glucose infusion was used to maintain euglycemia during sensor calibration period. At 0 min, 0.5 g/kg of bolus of glucose was administered, and at 50 min, 5 IU/kg of bolus of insulin was administered. Further glucose and insulin infusion was stopped at this time. The experiment was finished at 130 min and animals were euthanized. The time-shift between glycemia changes in blood, brain, and subcutaneous tissue was calculated by identification of the ideal correlation function. Moreover, the time to achieve 90 % of the maximum glucose excursion after intervention (T90) was measured to compare our data with the literature. The time-lag blood vs. brain and blood vs. subcutaneous tissue was 10 (10; 15) min and 15 (15; 25) min, respectively. The difference was statistically significant (P=0.01). T90 after glucose bolus in brain and subcutaneous tissue was 10 min (8.75; 15) and 15 min (13.75; 21.25), respectively. T90 after insulin bolus in brain and subcutaneous tissue was 10 min (10; 15) and 20 min (20; 27.5), respectively. To the contrary, with literature, our results showed earlier glucose level changes in brain in comparison with subcutaneous tissue after glucose and insulin boluses. Our results suggest that glucose dynamics is different within monitored tissues under rapid changing glucose level and we can expect similar behavior in humans. Improved knowledge about glucose distribution and dynamics is important for avoiding hypoglycemia.

[Surgical Treatment for Idiopathic Epiretinal Membrane]. / Chirurgická liecba idiopatických epiretinálnych membrán.

AIM: To assess effectiveness of surgical treatment for idiopathic epiretinal membrane. MATERIAL AND METHODS: Retrospective study included on 44 eyes out of 46 patients operated for idiopathic ERM in OFTAL Zvolen with a 20G PPV (32 patients) and posterior vitreous membrane ablation and 23G PPV (14 patients) from August 2008 to December 2014. After the extraction of epiretinal membrane, a peeling of ILM has been implemented following its Blue Membrane identification. Mean follow-up time was 18 months. RESULTS: Best corrected visual acuity (BCVA) before the surgery was 0.37 (SD 0.15) whereas post-surgery indicated 0.63 (SD 0.25). In 35 eyes (76.1%) was BCVA after the surgery 0,5 and better and in 2 eyes (4.3%) was BCVA 0,16 and worse. 29 eyes (63.0%) acquired 2 and more rows. BCVA improved in 40 eyes (87.0%) and remained the same in 3 eyes (6.5%). Degeneration of BCVA in 3 eyes (6.5%) was due to retinal detachment in one case, to retinal pigment epithelium (RPE) atrophy in the second case and to ischemic optic nerve head atrophy in the last case. According to OCT, the average mean of foveal thickness before the surgery was 496 (SD 88) µm and decreased to 356 (SD 59) µm after the surgery (thus average reduction of 140 µm). In 30 eyes (65.2%), we achieved a reduced foveal thickness of more than 100 µm, in comparison to 15 eyes (32.6%) of less than 100 µm. In no case after the surgery did retinal thickness increase comparing to finding before the surgery. Foveal contour restitution was present in 14 eyes (30.4%). There were no preoperative/ intraoperative complications. In 3 eyes (10.3%) a combined cataract surgery with PPV was performed. Cataract progression was seen in 20 phakic eyes (76.9%) out of 26 where all of them were treated surgically at an average time 13 (3-34) months after the PPV. As postoperative complication shows, a retinal detachment occurred in one eye (2.2%) 5 months after the surgery and in 1 eye (2.2%) a cystoid macular edema turned out as the reason of residual posterior vitreous adhesion. CONCLUSION: PPV with membranectomy and internal limiting membrane peeling is a safe and effective method in idiopathic epiretinal membrane treatment. It leads to a function improvement and foveal thickness reduction in most of the patients diagnosed with IEM. Because phakic eyes conduce cataract progression (76.9%), on older patients with no transparent lens we now perform a combination of surgical operations--pars plana vitrectomy and cataract extraction.

[New possibilities screening of refractive errors among children]. / Nové moznosti screeningu refrakcných porúch v detskom veku.

PURPOSE: To establish early detection of refractive errors among children in Slovakia. Different screening methods have been evaluated and compared in this work. MATERIALS AND METHODS: we have been working on a prospective study. Pre-school children in kindergardens in Central Slovakia were checked up between years 2009-2011. Effectiveness of various screening methods was compared within 2 groups, using test-type and Plusoptix Vision Screener. Parentes of children positive to refractive errors were recommended to consult a paediatrician ophthalmologist. RESULTS: 3982 children were examined. As a result, 13-14.1% of children who have not been examinated by the specialist, were positive. 53.3% of them went to see the doctor afterwards. CONCLUSION: establishment of early refractive errors screening is an important method how to prevent strabismus and amblyopia. It is very important to improve parentes knowledge about the risk of refractive errors and also to improve screening methods with collaboration with kindergarten teachers.

The relationship between glycemia, insulin and oxidative stress in hereditary hypertriglyceridemic rat.

The aim of this study was to determine the effects of insulin infusion on oxidative stress induced by acute changes in glycemia in non-stressed hereditary hypertriglyceridemic rats (hHTG) and Wistar (control) rats. Rats were treated with glucose and either insulin or normal saline infusion for 3 hours followed by 90 min of hyperglycemic (12 mmol/l) and 90 min of euglycemic (6 mmol/l) clamp. Levels of total glutathione (GSH), oxidized glutathione (GSSG) and total antioxidant capacity (AOC) were determined to assess oxidative stress. In steady states of each clamp, glucose infusion rate (GIR) was calculated for evaluation of insulin sensitivity. GIR (mg.kg(-1).min(-1)) was significantly lower in hHTG in comparison with Wistar rats; 25.46 (23.41 - 28.45) vs. 36.30 (27.49 - 50.42) on glycemia 6 mmol/l and 57.18 (50.78 - 60.63) vs. 68.00 (63.61 - 85.92) on glycemia 12 mmol/l. GSH/GSSG ratios were significantly higher in hHTG rats at basal conditions. Further results showed that, unlike in Wistar rats, insulin infusion significantly increases GSH/GSSG ratios in hHTG rats: 10.02 (9.90 - 11.42) vs. 6.01 (5.83 - 6.43) on glycemia 6 mmol/l and 7.42 (7.15 - 7.89) vs. 6.16 (5.74 - 7.05) on glycemia 12 mmol/l. Insulin infusion thus positively influences GSH/GSSG ratio and that way reduces intracellular oxidative stress in insulin-resistant animals.

Hyperinsulinemia and oxidative stress.

The aim of the study was to compare the effect of short-term hyperglycemia and short-term hyperinsulinemia on parameters of oxidative stress in Wistar rats. Twenty male rats (aged 3 months, average weight 325 g) were tested by hyperinsulinemic clamp (100 IU/l) at two different glycemia levels (6 and 12 mmol/l). Further 20 rats were used as a control group infused with normal saline (instead of insulin) and 30 % glucose simultaneously. Measured parameters of oxidative stress were malondialdehyd (MDA), reduced glutathion (GSH) and total antioxidant capacity (AOC). AOC remained unchanged during hyperglycemia and hyperinsulinemia. Malondialdehyde (as a marker of lipid peroxidation) decreased significantly (p<0.05) during the euglycemic hyperinsulinemic clamp, and increased significantly during isolated hyperglycemia without hyperinsulinemia. Reduced glutathion decreased significantly (p<0.05) during hyperglycemia without hyperinsulinemia. These results suggest that the short-term exogenous hyperinsulinemia reduced the production of reactive oxygen species (ROS) during hyperglycemia in an animal model compared with the control group.

[Metformin in the treatment of type 1 diabetics--a placebo controlled study]. / Metformin v lécbe diabetiku 1. typu--placebem kontrolovaná studie.

BACKGROUND: Metformin is popular for it's complex mechanism of action in treatment of the type 2. diabetes. The effect in type 1. diabetes is studied less frequently. The aim of our open, prospective, placebo controlled study was to assess the effect of metformin in poorly controlled diabetic patients type 1 with high insulin requirements. METHODS AND RESULTS: In the group comprised of 19 type 1 diabetic patients the insulin resistance was assessed by hyperinsulinemic euglycemic clamp and indirect calorimetry at the beginning of the study (B), 3 months later when metformin in the dose of 2 x 850 mg was added to existing insulin therapy (M) and after 3 months of placebo therapy (P). In the same time-intervals the other parameters were measured. Wilcoxon test was used for statistic analysis. All results are given in arithmetic average +/- SD. Weight (78.6 +/- 17.9; 75.7 +/- 17.8; 76.8 +/- 19.1 kg), Dauly insulin dose (65.4 +/- 15.1; 54.4 +/- 11.2; 54.8 +/- 9.3 IU), HbA1c (8.8 +/- 1.8; 8.2 +/- 1.1; 10.1 +/- 2.8%). Utilisation of glucose (3.5 +/- 1.6; 4.2 +/- 1.7; 4.4 +/- 1.8 mg/kg/min), triglycerides (1.2 +/- 0.5; 1.1 +/- 0.4; 1.3 +/- 0.7 mmol/l), cholesterol (5.1 +/- 0.7; 4.9 +/- 0.7; 5.2 +/- 0.8 mmol/l). CONCLUSIONS: The combination of metformin and the intensive insulin therapy in type 1 diabetic patients led, in contrast to placebo, to the significant reduction in weight (p < 0.001), to the reduction in insulin requirements (p < 0.05), to the improved control of glycaemia (p < 0.01) and to the decrease of FFA during clamp (p < 0.01).

[Short-term and long-term effect of metformin in type 1 diabetics]. / Krátkodobý a dlouhodobý úcinek metforminu u diabetiku 1. typu.

UNLABELLED: The objective of the investigation was to evaluate the effect of metformin added to the usual insulin treatment on insulin resistance, on the dose of substituted insulin and on the compensation of type 1 diabetes. METHOD: The first part of the study lasted 3 months, it was an open prospective study. The group was formed by 22 type 1 diabetics, average age 38.9 +/- 8.93 (min. 21, max. 55), with duration of diabetes of 13.8 +/- 6.43 years (min. 4, max. 29). Insulin resistance was assessed by means of a hyperinsular euglycaemic clamp (insulinaemia 100 mlU/l) at the onset of the study (B), after three months of metformin treatment which was added to the insulin regimen in a dose of 2 x 850 mg (M). After the same intervals the other investigasted parameters were assessed (body weight, daily insulin dose, glycated haemoglobin, triacylglycerols and cholesterol). The second part of the study was implemented after three years in the same group. The check-up examination (K) was attended by 21 diabetics who were divided into two groups: those who steadily used combined treatment (X, 8 patients) or were treated only with insulin (Y, 13 patients). The authors followed up the development of metabolic parameters in groups X and Y and the differences between them. RESULTS: After three months combined treatment reduction of body weight was recorded, on average by 2.23 kg (by 2.9 %, p < 0.001) and reduction of the daily insulin dose on average by 12.7 IU (by 20 %, p < 0.001). The decline of insulin resistance and glycated haemoglobin did not reach statistical significance. The lipaemia levels did not change. After three years the positive effect of combined treatment (group X vs. Y) wss preserved only as regards maintenance of body weight (p < 0.005). CONCLUSION: After adding metformin to the insulin regimen of type 2 diabetics after three months a statistically significant drop of body weight and the daily insulin dose occurred. Glycated haemoglobin and resistzance declined insignificantly. After follow up of the combined regime three years later only a positive effect on maintensance of the reduced body weight was recorded in group X vs. Y (p < 0.05).the other parameters in both groups did not differ statistically after three years.