Overexpression of Protein Phosphatase 2 Regulatory Subunit B"Alpha Promotes Glycolysis by Regulating Hexokinase 1 in Hepatocellular Carcinoma / 生物医学与环境科学（英文）

Objective@#To investigate the regulatory relationship of Protein Phosphatase 2 Regulatory Subunit B"Alpha ( PPP2R3A) and hexokinase 1 ( HK1) in glycolysis of hepatocellular carcinoma (HCC).@*Methods@#In HepG2 and Huh7 cells, PPP2R3A expression was silenced by small interfering RNA (siRNA) and overexpression by plasmid transfection. The PPP2R3A-related genes were searched by RNA sequencing. Glycolysis levels were measured by glucose uptake and lactate production. QRT-PCR, ELISA, western blot and immunofluorescence assay were performed to detect the changes of PPP2R3A and HK1. Cell proliferation, migration and invasion assay were used to study the roles of HK1 regulation by PPP2R3A.@*Results@#RNA sequencing data revealed that PPP2R3A siRNA significantly downregulated the expression of HK1. PPP2R3A gene overexpression promotes, while gene silencing suppresses, the level of HK1 and glycolysis in HCC cells. In HCC tissue samples, PPP2R3A and HK1 were colocalized in the cytoplasm, and their expression showed a positive correlation. HK1 inhibition abrogated the promotion of glycolysis, proliferation, migration and invasion by PPP2R3A overexpression in liver cancer cells.@*Conclusion@#Our findings showed the correlation of PPP2R3A and HK1 in the glycolysis of HCC, which reveals a new mechanism for the oncogenic roles of PPP2R3A in cancer.

Toxicity and metabolism of 3-bromopyruvate in Caenorhabditis elegans / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

In this study, we aimed to evaluate the toxic effects, changes in life span, and expression of various metabolism-related genes in Caenorhabditis elegans, using RNA interference (RNAi) and mutant strains, after 3-bromopyruvate (3-BrPA) treatment. C. elegans was treated with various concentrations of 3-BrPA on nematode growth medium (NGM) plates, and their survival was monitored every 24 h. The expression of genes related to metabolism was measured by the real-time fluorescent quantitative polymerase chain reaction (qPCR). Nematode survival in the presence of 3-BrPA was also studied after silencing three hexokinase (HK) genes. The average life span of C. elegans cultured on NGM with 3-BrPA was shortened to 5.7 d compared with 7.7 d in the control group. hxk-1, hxk-2, and hxk-3 were overexpressed after the treatment with 3-BrPA. After successfully interfering hxk-1, hxk-2, and hxk-3, the 50% lethal concentration (LC50) of all mutant nematodes decreased with 3-BrPA treatment for 24 h compared with that of the control. All the cyp35 genes tested were overexpressed, except cyp-35B3. The induction of cyp-35A1 expression was most obvious. The LC50 values of the mutant strains cyp-35A1, cyp-35A2, cyp-35A4, cyp-35B3, and cyp-35C1 were lower than that of the control. Thus, the toxicity of 3-BrPA is closely related to its effect on hexokinase metabolism in nematodes, and the cyp-35 family plays a key role in the metabolism of 3-BrPA.

Alteration in plasma chemokine profile in a high-fat diet-induced obesity mouse model / 한국영양학회지

PURPOSE: Obesity is associated with a dysregulation of metabolic balance and is regarded as a low grade chronic inflammation. Western-style diet and physical inactivity are leading causes of obesity. This study examined the profiles of forty plasma cytokines and chemokines at the same time in the early stages of high-fat diet-induced obesity using a mouse model. METHODS: A total of 30 male CD1 mice, 12 ~ 14 weeks of age, were enrolled. The mice were fed a high-fat diet for 6 weeks to induce obesity. The plasma glucose and triglyceride concentrations were measured using a hexokinase colorimetric assay kit and a serum triglyceride determination kit, respectively. The relative levels of multiple cytokines and chemokines in the plasma were determined using a mouse cytokine array kit. RESULTS: The mice exhibited significant weight gain after 6 weeks of a high-fat diet. The genital fat depot was enlarged along with an increase in the number and the mean size of white adipocytes as early as 4 weeks after a high-fat diet. In addition, the plasma glucose and triglyceride levels increased significantly after 4 weeks of a high-fat diet. Cytokine array analysis revealed a remarkable increase in the expression of both CXCL12 and CXCL13, whereas the proinflammatory cytokines remained low after 4 weeks of a high-fat diet. CONCLUSION: A significant increase in plasma levels of CXCL12 and CXCL13 was observed after 4 weeks of a high-fat diet, which might induce the migration of B lymphocytes, T lymphocytes, and monocytes from the blood to expanding adipose tissue or fat associated lymphoid clusters, playing a key role in adipose tissue remodeling and local immunity during the early stages of high-fat diet-induced obesity.

mRNA Expression of SLC5A5 and SLC2A Family Genes in Papillary Thyroid Cancer: An Analysis of The Cancer Genome Atlas

PURPOSE: The present study investigated the dynamics and prognostic role of messenger RNA (mRNA) expression responsible for 18F-fluorodeoxyglucose (FDG) uptake in FDG positron emission tomography (PET) and radioactive iodine (131I) uptake in whole-body radioactive iodine scans (WBS) in papillary thyroid cancer (PTC) patients. MATERIALS AND METHODS: The primary and processed data were downloaded from the Genomic Data Commons Data Portal. Expression data for sodium/iodide symporter (solute carrier family 5 member 5, SLC5A5), hexokinase (HK1–3), glucose-6-phosphate dehydrogenase (G6PD), and glucose transporter (solute carrier family 2, SLC2A1–4) mRNA were collected. RESULTS: Expression of SLC5A5 mRNA were negatively correlated with SLC2A1 mRNA and positively correlated with SLC2A4 mRNA. In PTC with BRAF mutations, expressions of SLC2A1, SLC2A3, HK2, and HK3 mRNA were higher than those in PTC without BRAF mutations. Expression of SLC5A5, SLC2A4, HK1, and G6PD mRNA was lower in PTC without BRAF mutation. PTCs with higher expression of SLC5A5 mRNA had more favorable disease-free survival, but no association with overall survival. CONCLUSION: Expression of SLC5A5 mRNA was negatively correlated with SLC2A1 mRNA. This finding provides a molecular basis for the management of PTC with negative WBS using 18F-FDG PET scans. In addition, higher expression of SLC5A5 mRNA was associated with less PTC recurrence, but not with deaths.

Usefulness of Dipstick Test for Vitreous Glucose in Autopsy Practice / 대한법의학회지

The concentration of glucose in the vitreous humor serves as an important diagnostic marker for diabetic mellitus in post-mortem examinations, as the vitreous humor can be easily collected and the glucose test using vitreous humor is not significantly affected by cell autolysis and hemolysis. For a quick and effective glucose test, we suggest a dipstick test of the vitreous humor during autopsy. The results were evaluated and compared with other methods for significance testing. In this study, vitreous humor was analyzed from 257 autopsy cases. Qualitative concordance rate of the dipstick test for glucose and the hexokinase test was 98.7%, positive prediction rate was 89.6%, and negative prediction rate was 100%. However, there was no significant correlation between the dipstick glucose test and the hexokinase test. We conclude that the dipstick glucose test is effective and useful for post-mortem glucose screening testing and for additional post-mortem diabetes testing. Recently, the importance of post-mortem glucose testing has increased with the increase in deaths from diabetes complications. The use of the dipstick glucose test in autopsy practice can improve forensic medicine in Korea.

Poly(ADP-ribose) polymerase regulates glycolytic activity in kidney proximal tubule epithelial cells / 대한해부학회지

After renal injury, selective damage occurs in the proximal tubules as a result of inhibition of glycolysis. The molecular mechanism of damage is not known. Poly(ADP-ribose) polymerase (PARP) activation plays a critical role of proximal tubular cell death in several renal disorders. Here, we studied the role of PARP on glycolytic flux in pig kidney proximal tubule epithelial LLC-PK1 cells using XFp extracellular flux analysis. Poly(ADP-ribosyl)ation by PARP activation was increased approximately 2-fold by incubation of the cells in 10 mM glucose for 30 minutes, but treatment with the PARP inhibitor 3-aminobenzamide (3-AB) does-dependently prevented the glucose-induced PARP activation (approximately 14.4% decrease in 0.1 mM 3-AB-treated group and 36.7% decrease in 1 mM 3-AB-treated group). Treatment with 1 mM 3-AB significantly enhanced the glucose-mediated increase in the extracellular acidification rate (61.1±4.3 mpH/min vs. 126.8±6.2 mpH/min or approximately 2-fold) compared with treatment with vehicle, indicating that PARP inhibition increases only glycolytic activity during glycolytic flux including basal glycolysis, glycolytic activity, and glycolytic capacity in kidney proximal tubule epithelial cells. Glucose increased the activities of glycolytic enzymes including hexokinase, phosphoglucose isomerase, phosphofructokinase-1, glyceraldehyde-3-phosphate dehydrogenase, enolase, and pyruvate kinase in LLC-PK1 cells. Furthermore, PARP inhibition selectively augmented the activities of hexokinase (approximately 1.4-fold over vehicle group), phosphofructokinase-1 (approximately 1.6-fold over vehicle group), and glyceraldehyde-3-phosphate dehydrogenase (approximately 2.2-fold over vehicle group). In conclusion, these data suggest that PARP activation may regulate glycolytic activity via poly(ADP-ribosyl)ation of hexokinase, phosphofructokinase-1, and glyceraldehyde-3-phosphate dehydrogenase in kidney proximal tubule epithelial cells.

miR-181c inhibits glycolysis by targeting hexokinase 2 in cancer-associated fibroblasts / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of miR-181c in glycolysis of cancer-associated fibroblasts (CAFs) and explore the mechanism.</p><p><b>METHODS</b>Human lung CAFs and normal fibroblasts (NFs), isolated from fresh human lung adenocarcinoma tissue specimens by primary culture of tissue explants, were transfected with a miR -181c mimics, a miR-181c inhibitor, a siRNA siRNA-HK2 or the vector HK2-vector via Lipofectamine(TM) 2000. Quantitative real-time PCR was used to analyze the changes in miR-125b expression in the transfected cells; hexokinase-2 (HK2) protein expression in the cells was detected using Western blotting, and the cellular glucose uptake was assessed with 2-NBDG. Lactate production in the cells was examined and expression of HK2 mRNA was detected with dual luciferase reporter gene assay.</p><p><b>RESULTS</b>No obvious difference was found in the cell morphology between CAFs and NFs. Compared with the NFs, the CAFs showed obviously increased glucose uptake, lactate production and HK2 protein expression with decreased expressions of the miR-181 family (P<0.05). Transfection with the miR-181 inhibito- rsignificantly increased glucose uptake, lactate production and HK2 protein expression in the NFs. In CAFs, transfection with the miR-181 mimics caused significantly lowered glucose uptake, lactate production and HK2 protein expression of. Knockdown of endogenous HK2 by siRNA abolished miR-181 mimics-mediated decrease of glucose uptake and lactate production in CAFs, while transfection with miR-181 mimics suppressed HK2 overexpression-induced enhancement of glucose uptake and lactate production in NFs.</p><p><b>CONCLUSION</b>Transfection with miR-181 mimics can suppress glycolysis in CAFs by inhibiting HK2 expression.</p>

Suppression of miR-181 a attenuates H2O2-induced death of mesenchymal stem cells by maintaining hexokinase II expression

BACKGROUND: Low survival rate of transplanted cells compromises the efficacy of cell therapy. Hexokinase II (HKII) is known to have anti-apoptotic activity through its interaction with mitochondria. The objective was to identify miRNAs targeting HKII and investigate whether miRNA-mediated modulation of HKII could improve the survival of mesenchymal stem cells (MSCs) exposed to H2O2. The expression of HKII in MSCs exposed to H2O2 was evaluated, and HKII-targeting miRNA was screened based on miRNA-target prediction databases. The effect of H2O2 on the expression of the selected HKII-targeting miRNA was examined and the effect of modulation of the selected HKII-targeting miRNA using anti-miRNA on H2O2-induced apoptosis of MSC was evaluated. RESULTS: H2O2 (600 µM) induced cell death of MSCs and decreased mitochondrial HKII expression. We have identified miR-181a as a HKII-targeting miRNA and H2O2 increased the expression of miR-181a in MSCs. Delivery of anti-miR-181a, which neutralizes endogenous miR-181a, significantly attenuated H2O2-induced decrease of HKII expression and disruption of mitochondrial membrane potential, improving the survival of MSCs exposed to H2O2. CONCLUSIONS: These findings suggest that H2O2-induced up-regulation of miR-181a contributes to the cell death of MSCs by down-regulating HKII. Neutralizing miR-181a can be an effective way to prime MSCs for transplantation into ischemic tissues.

Yeast HXK2 gene reverts glucose regulation mutation of penicillin biosynthesis in P. chrysogenum

The mutant Penicillium chrysogenum strain dogR5, derived from strain AS-P-78, does not respond to glucose regulation of penicillin biosynthesis and β-galactosidase, and is partially deficient in D-glucose phosphorilating activity. We have transformed strain dogR5 with the (hexokinase) hxk2 gene from Saccharomyces cerevisiae. Transformants recovered glucose control of penicillin biosynthesis in different degrees, and acquired a hexokinase (fructose phosphorylating) activity absent in strains AS- P-78 and dogR5. Interestingly, they also recovered glucose regulation of β-galactosidase. On the other hand, glucokinase activity was affected in different ways in the transformants; one of which showed a lower activity than the parental dogR5, but normal glucose regulation of penicillin biosynthesis. Our results show that Penicillium chrysogenum AS-P-78 and dogR5 strains lack hexokinase, and suggest that an enzyme with glucokinase activity is involved in glucose regulation of penicillin biosynthesis and β-galactosidase, thus signaling glucose in both primary and secondary metabolism; however, catalytic and signaling activities seem to be independent.

Safety and outcome of treatment of metastatic melanoma using 3-bromopyruvate: a concise literature review and case study / 癌症

3-Bromopyruvate (3BP) is a new, promising anticancer alkylating agent with several notable functions. In addition to inhibiting key glycolysis enzymes including hexokinase II and lactate dehydrogenase (LDH), 3BP also selectively inhibits mitochondrial oxidative phosphorylation, angiogenesis, and energy production in cancer cells. Moreover, 3BP induces hydrogen peroxide generation in cancer cells (oxidative stress effect) and competes with the LDH substrates pyruvate and lactate. There is only one published human clinical study showing that 3BP was effective in treating fibrolamellar hepatocellular carcinoma. LDH is a good measure for tumor evaluation and predicts the outcome of treatment better than the presence of a residual tumor mass. According to the Warburg effect, LDH is responsible for lactate synthesis, which facilitates cancer cell survival, progression, aggressiveness, metastasis, and angiogenesis. Lactate produced through LDH activity fuels aerobic cell populations inside tumors via metabolic symbiosis. In melanoma, the most deadly skin cancer, 3BP induced necrotic cell death in sensitive cells, whereas high glutathione (GSH) content made other melanoma cells resistant to 3BP. Concurrent use of a GSH depletor with 3BP killed resistant melanoma cells. Survival of melanoma patients was inversely associated with high serum LDH levels, which was reported to be highly predictive of melanoma treatment in randomized clinical trials. Here, we report a 28-year-old man presented with stage IV metastatic melanoma affecting the back, left pleura, and lung. The disease caused total destruction of the left lung and a high serum LDH level (4,283 U/L). After ethics committee approval and written patient consent, the patient received 3BP intravenous infusions (1-2.2 mg/kg), but the anticancer effect was minimal as indicated by a high serum LDH level. This may have been due to high tumor GSH content. On combining oral paracetamol, which depletes tumor GSH, with 3BP treatment, serum LDH level dropped maximally. Although a slow intravenous infusion of 3BP appeared to have minimal cytotoxicity, its anticancer efficacy via this delivery method was low. This was possibly due to high tumor GSH content, which was increased after concurrent use of the GSH depletor paracetamol. If the anticancer effectiveness of 3BP is less than expected, the combination with paracetamol may be needed to sensitize cancer cells to 3BP-induced effects.

Pharmacological evaluation of hyperin for antihyperglycemic activity and effect on lipid profile in diabetic rats.

Antihyperglycemic potential of hyperin at 25 and 50 mg/kg doses for 30 days to streptozotocin induced diabetic rats has been reported. In oral glucose tolerance test, hyperin treated rats showed a significant reduction in blood glucose level after 120 min. It was found that hyperin exhibited dose dependent and significant antihyperglycemic activity in streptozotocin induced diabetic rats which were nearly similar with standard drug glybenclamide. Activities of glucose-6-phosphatase, fructose-1,6-bisphosphatase, glycogen phosphorylase, glycosylated haemoglobin and level of serum urea and creatinine were significantly decreased in hyperin supplemented diabetic rats, dose dependently. Activities of hexokinase and glycogen synthase were increased with augmentation in liver glycogen, insulin and haemoglobin content in hyperin treated diabetic rats. General hematological parameters did not show any significant change in hyperin treated diabetic rats hence it is safe at these doses. Histopathological studies showed significant morphological changes in pancreatic β-cells of streptozotocin induced diabetic rats. A decreased number of secretory granules of β- cells were observed in diabetic rats and these pathological abnormalities were normalized after treatment with hyperin and standard drug glybenclamide. Further, hyperin decreases significant in serum total cholesterol, triglyceride, low density lipoprotein, very low density lipoprotein levels coupled with elevation of high density lipoprotein in diabetic rats. These results suggest that hyperin has a pivotal role in blood glucose level in streptozotocin induced hyperglycemia by improving the function of pancreatic islets and increasing glycolysis and decreasing gluconeogenesis.

Prosapogenin A inhibits cell growth of MCF7 via downregulating STAT3 and glycometabolism-related gene / 药学学报

This study is to investigate the inhibitory effect and mechanism of prosapogenin A (PSA) on MCF7. MTT assay was performed to determine the inhibitory effect of PSA on MCF7 cells. PI/Hoechst 33342 double staining was used to detect cell apoptosis. RT-PCR was used to test the mRNA levels of STAT3, GLUT1, HK and PFKL. Western blotting was performed to determine the expression of STAT3 and pSTAT3 protein in MCF7 cells. The results showed that PSA could dose-dependently inhibit cell growth of MCF7 followed by IC50 of 9.65 micrmol x L(-1) and promote cell apoptosis of MCF7. Reduced mRNA levels of STAT3, HK and PFKL were observed in MCF7 cells treated with 5 micromol x L(-1) of PSA. PSA also decreased the level of pSTAT3 protein. STAT3 siRNA caused decrease of mRNA of GLUT1, HK and PFKL which indicated STAT3 could regulate the expressions of GLUT1, HK and PFKL. The results suggested that PSA could inhibit cell growth and promote cell apoptosis of MCF7 via inhibition of STAT3 and glycometabolism-related gene.

Trueness Assessment for Serum Glucose Measurement Using Commercial Systems through the Preparation of Commutable Reference Materials

BACKGROUND: Commutable reference materials (RMs) are suitable for end-users for evaluating the metrological traceability of values obtained using routine measurement systems. We assessed the performance of 6 routine measurement systems with validated secondary RMs. METHODS: We tested the homogeneity, stability, and commutability of 5 minimally processed human serum pools according to the standard guidelines. The serum pools were assigned values as per the reference procedure of the United States Centers for Disease Control and were used to evaluate the trueness of results from 6 commercial measurement systems based on enzymatic methods: 3 glucose oxidase (GOD) and 3 hexokinase (HK) methods. RESULTS: The prepared RMs were validated to be sufficiently homogenous, stable, and commutable with the patient samples. Method bias varied for different systems: GOD01, -0.17 to 2.88%; GOD02, 1.66 to 4.58%; GOD03, -0.17 to 3.14%; HK01, -3.48 to -0.85%; HK02, -3.83 to -0.11%, and HK03, -1.82 to -0.27%. CONCLUSIONS: We observed that the prepared serum glucose RMs were qualified for trueness assessment. Most of the measurement systems met the minimal quality specifications.

Platelet enzyme abnormalities in leukemias.

Aim of the Study: The aim of this study was to evaluate platelet enzyme activity in cases of leukemia. Materials and Methods: Platelet enzymes glucose-6-phosphate dehydrogenase (G6PD), pyruvate kinase (PK) and hexokinase (HK) were studied in 47 patients of acute and chronic leukemia patients, 16 patients with acute myeloid leukemia (AML)(13 relapse, three in remission), 12 patients with acute lymphocytic leukemia (ALL) (five in relapse, seven in remission), 19 patients with chronic myeloid leukemia (CML). Results: The platelet G6PD activity was significantly low in cases of AML, ALL and also in CML. G6PD activity was normalized during AML remission. G6PD activity, although persistently low during ALL remission, increased significantly to near-normal during remission (P < 0.05) as compared with relapse (P < 0.01). Platelet PK activity was high during AML relapse (P < 0.05), which was normalized during remission. Platelet HK however was found to be decreased during all remission (P < 0.05). There was a significant positive correlation between G6PD and PK in cases of AML (P < 0.001) but not in ALL and CML. G6PD activity did not correlate with HK activity in any of the leukemic groups. A significant positive correlation was however seen between PK and HK activity in cases of ALL remission (P < 0.01) and CML (P < 0.05). Conclusions: Both red cell and platelet enzymes were studied in 36 leukemic patients and there was no statistically significant correlation between red cell and platelet enzymes. Platelet enzyme defect in leukemias suggests the inherent abnormality in megakaryopoiesis and would explain the functional platelet defects in leukemias.

Pre- and post-treatment of streptozocin administered rats with melatonin: effects on some hepatic enzymes of carbohydrate metabolism

Melatonin, found in high concentrations in the pineal gland, organs within the digestive system and in some plants and fungi, acts as an antioxidant which decreases reactive oxygen species in streptozocin-induced diabetic rats, raises insulin secretion by the pancreatic [3-cells and increases the number of insulin receptors on hepatocyte membranes. The protective and therapeutic effects of melatonin feeding in streptozocin-induced diabetic rats were studied. Streptozocin administered rats were gavaged with melatonin, pre- and post-treatment, at a level of 5 mg/kg body weight daily for a period of 15 days. Levels of plasma glucose, cholesterol, triacylglycerol, oral glucose tolerance test, and some hepatic enzymes of carbohydrate metabolism including insulin inducible glucokinase, hexokinase and glucose 6-P dehydrogenase were measured using standard methods and compared with the values in normoglycemic and diabetic control groups. Both pre- and post-treatment of the Streptozocin administered rats with melatonin normalized plasma glucose, cholesterol, and triacylglycerol, improved oral glucose tolerance test and increased hepatic glucokinase, hexokinase and glucose 6-P dehydrogenase specific activities to the levels seen in normal rats. Melatonin pre-treatment prevents the injurious effects of Streptozocin in rats. In Streptozocin induced diabetic animals, post-treatment with this antioxidant normalizes both blood and liver constituents which were ameliorated by Streptozocin

Impact of distillage recycling on the glycolysis key enzymes, stress response metabolites and intracelluler components of the self-flocculating yeast / 生物工程学报

This research aimed to study the effect of distillage recycling on ethanol fermentation, the key glycolytic enzymes and cell composition of the self-flocculating yeast. With the self-flocculating yeast SPSC01 and medium composed of 220 g/L glucose, 8 g/L yeast extract and 6 g/L peptone, continuous ethanol fermentation was carried out at the dilution rate of 0.04 h(-1) with a 1.5 L tank bioreactor. Fermentation broth was collected every 3 days, and ethanol and other volatile byproducts were removed by distillation, but the stillage with high boiling byproducts was recycled to prepare the medium instead of fresh water. The system was run for 20 days, during which ethanol and biomass concentrations in the effluent decreased continuously, indicating the significant inhibition of the high boiling byproducts accumulated within the system. Thus, the activities of the key enzymes of the glycolytic pathway: hexokinase, 6-phosphofructose kinase, and pyruvate kinase were analyzed, and it was observed that all of them were inhibited. Furthermore, the biosynthesis of the stress response metabolites glycerol and trehalose was investigated, and it was found that glycerol production that can protect yeast cells against osmotic pressure stress was enhanced, but trehalose biosynthesis that can protect yeast cells against ethanol inhibition was not improved, correspondingly. And in the meantime, the biosynthesis of the major intracellular components proteins and hydrocarbons was adjusted, correspondingly.

The Correlation and Accuracy of Glucose Levels between Interstitial Fluid and Venous Plasma by Continuous Glucose Monitoring System / 당뇨병

BACKGROUND: Clinical experience with the continuous glucose monitoring systems (CGMS) is limited in Korea. The objective of this study is to evaluate the accuracy of the CGMS and the correlation between interstitial fluid and venous plasma glucose level in Korean healthy male subjects. METHODS: Thirty-two subjects were served with glucose solution contained same amount of test food's carbohydrate and test foods after separate overnight fasts. CGMS was performed over 3 days during hopitalization for each subjects. Venous plasma glucose measurements were carried out during 4 hours (0, 0.25, 0.5, 0.75, 1, 2, 4 hours) just before and after glucose solution and test food load. The performance of the CGMS was evaluated by comparing its readings to those obtained at the same time by the hexokinase method using the auto biochemistry machine (Hitachi 7600-110). Also, correlations between glucose recorded with CGMS and venous plasma glucose value were examined. RESULTS: CGMS slightly underestimated the glucose value as compared with the venous plasma glucose level (16.3 +/- 22.2 mg/dL). Correlation between CGMS and venous plasma glucose values throughout sensor lifetime is 0.73 (regression analysis: slope = 1.08, intercept = 8.38 mg/dL). Sensor sensitivity can deteriorate over time, with correlations between venous blood glucose and CGMS values dropping from 0.77 during 1st day to 0.65 during 2nd and 3rd day. CONCLUSION: The accuracy of data provided by CGMS may be less than expected. CGMS sensor sensitivity is decreased with the passage of time. But, from this study, CGMS can be used for glucose variability tendency monitoring conveniently to the Korean.

Evaluation of CareSens(R) N Glucometer Glucose Monitoring System / 임상검사와정도관리

BACKGROUND: Point-of-care testing (POCT) glucometers are widely being used for management of diabetes. We examined the analytical performance of the recently developed glucometer CareSens(R) N Glucometer (i-SENS Inc., Korea). METHODS: CareSens N was evaluated for linearity, precision, and the effect of hematocrit. Method comparison using the laboratory reference method, hexokinase method by Hitachi 7600 (Hitachi Co., Japan) was also performed. Other glucometers, Accu-Chek(R) inform (Roche Diagnostics LTD., Germany) and Onetouch(R) ultra(TM) (Lifescan Inc., USA) were evaluated for the same categories according to CLSI guidelines. RESULTS: CareSens N Glucometer showed a good linearity and precision. The linearity was r=0.9965. The coefficients of variations (CVs) of within-run precision were 0.73-1.98% and CVs of total precision were 1.65-2.71%. A high correlation (glucose by CareSens N = 0.9767 x glucose by Hitachi 7600 + 4.1734, r=0.9614) was also shown between the CareSens N glucometer and Hitachi 7600 in the central laboratory. Other glucometers showed a good linearity. The within-run and total-run CVs of other glucometers were within 10%. Although differences with the reference method were within allowable ranges, all glucometers showed variable bias compared with the reference method. Overestimation or underestimation of glucose values were observed by change of hematocrit in range of 31.1 to 51.2%. CONCLUSIONS: CareSens N showed good linearity, precision, and correlation with reference method. CareSens N provided reliable result of blood glucose and seems appropriate for clinical use in the management of diabetic patients.