Diabetic Erythrocytes Research Articles

Effects of low doses of gamma rays on the stability of normal and diabetic erythrocytes.

We studied the influence of low doses of γ radiation (from 0.04 to 1.8 mGy) on the stability of human red blood cells (RBC) from healthy donors and diabetic patients using absorption spectroscopy. Because of the alteration of many enzymatic pathways in diabetic RBCs resulting in strong modification of the lipid and protein membrane components one could expect that the ionizing γ-radiation should influence the stability of the healthy and diabetic cells in a different way. Indeed, distinct discontinuities and monotonic changes of hemolysis detected in the healthy and diabetic RBCs suggest that various enzymatic and chemical processes are activated in these membranes by γ radiation. Mössbauer measurements showed that only the highest applied dose of γ radiation caused modification of hemoglobin in both types of RBCs.

L-Cysteine influx in type 2 diabetic erythrocytes

Erythrocyte oxidative stress has been implicated in the pathogenesis of diabetes mellitus, and the deficiency of antioxidant defense by the glutathione (GSH) pathway is thought to be one of the factors responsible for development of complications in diabetes. Erythrocytes require L-cysteine for the synthesis of GSH and the rate of synthesis is determined only by L-cysteine availability. In the present study we have found that the L-cysteine influx in erythrocytes from type 2 diabetic patients was significantly lower compared to age-matched controls. The decreased influx may be one of the factors leading to low GSH concentration observed in type 2 diabetes. Since L-cysteine is the limiting amino acid in GSH synthesis, any strategy aimed to increase L-cysteine influx in erythrocytes may be beneficial for type 2 diabetic patients.

L-Cysteine Influx in Type 2 Diabetic Erythrocytes

Erythrocyte oxidative stress has been implicated in the pathogenesis of diabetes mellitus, and the deficiency of antioxidant defense by the glutathione (GSH) pathway is thought to be one of the factors responsible for development of complications in diabetes. Erythrocytes require L-cysteine for thesynthesis of GSH and the rate of synthesis is determined only by L-cysteine availability. In the present study we have found that the L-cysteine influx in erythrocytes from type 2 diabetic patients was significantly lower compared to age-matched controls. The decreased influx may be one of the factors leading to low GSH concentration observed in type 2 diabetes. Since L-cysteine is the limiting amino acid in GSH synthesis, any strategy aimed to increase L-cysteine influx in erythrocytes may be beneficial for type 2 diabetic patients.

The Alterations of Erythrocyte Phospholipids in Type 2 Diabetes Observed after Oral High-Fat Meal Loading: The FTIR Spectroscopic and Mass Spectrometric Studies

Little is known about the postprandial remodelling of erythrocytes phospholipids (PLs) in type 2 diabetics (T2DM). Therefore, this study aims to compare the alterations of erythrocyte PLs in T2DM to those of healthy subjects after ingestion of a high-fat meal. Eleven T2DM and ten healthy subjects underwent a high-fat meal loading. Erythrocytes were isolated from blood obtained after fasting and 4 h after the meal. Fourier Transform Infrared (FTIR) spectroscopy was initially used to screen erythrocyte PLs by monitoring C-H stretching vibrations. Phosphatidylcholine (PC) molecular species were further investigated by Liquid Chromatography-Electrospray Ionisation-Mass Spectrometry (LC-ESI-MS). For the control group, FTIR revealed postprandial changes in C-H stretching vibrations, particularly of the olefinic band. These findings were supported by LC-ESI-MS data, showing marked changes in PC molecular species, especially of the PC34:1 (where 34 and 1 mean the summed number of carbons and double bonds, respectively). However, similar changes of those were not apparent in the T2DM group. Our results reveal marked postprandial alterations of erythrocyte PC species in healthy subjects whereas only mild alterations are observed in T2DM. The discrepant effects of high-fat meal loading suggest abnormal PC remodelling in the diabetic erythrocyte that may affect its membrane fluidity and integrity.

Analysis of Retina and Erythrocyte Glycerophospholipid Alterations in a Rat Model of Type 1 Diabetes.

An automated tandem mass spectrometry based analysis employing precursor ion and neutral loss scans in a triple quadrupole mass spectrometer has been employed to identify and quantify changes in the abundances of glycerophospholipids extracted from retina and erythrocytes in a rat streptozotocin model of type 1 diabetes, 6 weeks and 36 weeks following induction of diabetes, compared to age matched nondiabetic controls. The utility of an 'internal standard' method compared to an 'internal standard free' method for quantification of differences in the abundances of specific lipid ions was evaluated in both retina and erythrocyte lipid extracts. In retina, equivalent results were obtained by using the internal standard and 'internal standard free' methods for quantification. In erythrocytes, the two methods of analysis yielded significantly different results, suggesting that factors intrinsic to particular sample types may influence the outcome of label-free lipidome quantification approaches.Overall increases (~25% to ~35%) in the abundances of major retina glycerophospholipid classes were demonstrated in rats at 6 weeks of diabetes, relative to control animals. However, at 36 weeks of diabetes, subsequent overall decreases in retina glycerophosphocholine and glycerophosphoethanolamine abundances of 16% and 33%, respectively, were observed. Additionally, retina and erythrocyte glycerophosphocholine lipids at both 6 week and 36 weeks of diabetes exhibited increased incorporation of linoleic acid((18:2n6)) and a decrease in docosahexaenoic acid (DHA((22:6n3))) content. Finally, an approximately 5-fold increase in the abundances of specific glycated glycerophosphoethanolamine (Amadori-GPEtn) lipids were observed in the retina of 36 week diabetic rats, with a corresponding 1.6 fold increase of Amadori-GPEtn lipids in diabetic erythrocytes.

Myricetin May Provide Protection against Oxidative Stress in Type 2 Diabetic Erythrocytes

Oxidative stress is believed to be a major contributing factor in the development of late complications of diabetes. Many in vitro and in vivo studies have demonstrated that several parameters of red blood cell function and integrity are negatively affected by increased oxidative stress. Plant polyphenols are reported to exert many biological effects due to their antioxidant property. The present study was undertaken to evaluate the antioxidant effect of myricetin on markers of oxidative stress in erythrocytes from type 2 diabetic patients. The study was carried out on blood samples obtained from 23 type 2 diabetic patients and 23 age-matched control subjects. Erythrocytes were subjected to in vitro oxidative stress by incubating with 10(-5) M tert-butyl hydroperoxide (t-BHP). Erythrocyte membrane lipid peroxidation and protein oxidation were measured in terms of malondialdehyde (MDA) and protein carbonyl group levels. The results showed an elevated MDA and protein carbonyl content in diabetic erythrocytes which were further increased after incubation with t-BHP. Myricetin at micromolar concentration significantly (p < 0.01) protected an t-BHP-induced increase in levels of oxidative stress parameters of diabetic erythrocytes.

Personalized Metabolic Assessment of Erythrocytes Using Microfluidic Delivery to an Array of Luminescent Wells

The metabolic syndrome is often described as a group of risk factors associated with diabetes. These risk factors include, but are not limited to, such conditions as insulin resistance, obesity, high blood pressure, and oxidant stress. Here, we report on a tool that may provide some clarity on the relationship between some of these associated risk factors, especially oxidant stress and hypertension. Specifically, we describe the ability to simultaneously monitor nicotinamide dinucleotide phosphate (NADPH), reduced glutathione (GSH), and shear-induced adenosine triphosphate (ATP) release from erythrocytes using luminescence detection on a microfabricated device. The measurements are performed by delivering erythrocyte lysate (for the NADPH and GSH measurements, two analytes indicative of oxidative stress) or whole red blood cells (RBCs) (for the determination of ATP release from the cells) to an array of wells that contain the necessary reagents to generate a luminescence emission that is proportional to analyte concentration. A fluorescence macrostereomicroscope enables whole-chip imaging of the resultant emission. The concentrations of each NADPH and GSH contained within a 0.7% erythrocyte solution were determined to be 31.06 +/- 4.12 and 22.55 +/- 2.47 microM, respectively, and the average ATP released from a nonlysed 7% erythrocyte solution was determined to be 0.54 +/- 0.04 microM. Collectively, the device represents a precursor to subsequent merging of microfluidics and microtiter-plate technology for high-throughput assessment of metabolite profiles in the diabetic erythrocyte.

Zinc-activated C-peptide resistance to the type 2 diabetic erythrocyte is associated with hyperglycemia-induced phosphatidylserine externalization and reversed by metformin

Insulin resistance can broadly be defined as the diminished ability of cells to respond to the action of insulin in transporting glucose from the bloodstream into cells and tissues. Here, we report that erythrocytes (ERYs) obtained from type 2 diabetic rats display an apparent resistance to Zn(2+)-activated C-peptide. Thus, the aims of this study were to demonstrate that Zn(2+)-activated C-peptide exerts potentially beneficial effects on healthy ERYs and that these same effects on type 2 diabetic ERYs are enhanced in the presence of metformin. Incubation of ERYs (obtained from type 2 diabetic BBZDR/Wor-rats) with Zn(2+)-activated C-peptide followed by chemiluminescence measurements of ATP resulted in a 31.2 +/- 4.0% increase in ATP release from these ERYs compared to a 78.4 +/- 4.9% increase from control ERYs. Glucose accumulation in diabetic ERYs, measured by scintillation counting of (14)C-labeled glucose, increased by 35.8 +/- 1.3% in the presence of the Zn(2+)-activated C-peptide, a value significantly lower than results obtained from control ERYs (64.3 +/- 5.1%). When Zn(2+)-activated C-peptide was exogenously added to diabetic ERYs, immunoassays revealed a 32.5 +/- 8.2% increase in C-peptide absorbance compared to a 64.4 +/- 10.3% increase in control ERYs. Phosphatidylserine (PS) externalization and metformin sensitization of Zn(2+)-activated C-peptide were examined spectrofluorometrically by measuring the binding of FITC-labeled annexin to PS. The incubation of diabetic ERYs with metformin prior to the addition of Zn(2+)-activated C-peptide resulted in values that were statistically equivalent to those of controls. Summarily, data obtained here demonstrate an apparent resistance to Zn(2+)-activated C-peptide by the ERY that is corrected by metformin.

Site-specific GlcNAcylation of human erythrocyte proteins: potential biomarker(s) for diabetes.

OBJECTIVE—O-linked N-acetylglucosamine (O-GlcNAc) is upregulated in diabetic tissues and plays a role in insulin resistance and glucose toxicity. Here, we investigated the extent of GlcNAcylation on human erythrocyte proteins and compared site-specific GlcNAcylation on erythrocyte proteins from diabetic and normal individuals.RESEARCH DESIGN AND METHODS—GlcNAcylated erythrocyte proteins or GlcNAcylated peptides were tagged and selectively enriched by a chemoenzymatic approach and identified by mass spectrometry. The enrichment approach was combined with solid-phase chemical derivatization and isotopic labeling to detect O-GlcNAc modification sites and to compare site-specific O-GlcNAc occupancy levels between normal and diabetic erythrocyte proteins.RESULTS—The enzymes that catalyze the cycling (addition and removal) of O-GlcNAc were detected in human erythrocytes. Twenty-five GlcNAcylated erythrocyte proteins were identified. Protein expression levels were compared between diabetic and normal erythrocytes. Thirty-five O-GlcNAc sites were reproducibly identified, and their site-specific O-GlcNAc occupancy ratios were calculated.CONCLUSIONS—GlcNAcylation is differentially regulated at individual sites on erythrocyte proteins in response to glycemic status. These data suggest not only that site-specific O-GlcNAc levels reflect the glycemic status of an individual but also that O-GlcNAc site occupancy on erythrocyte proteins may be eventually useful as a diagnostic tool for the early detection of diabetes.

Diabetic erythrocytes test by correlation coefficient.

Even when a healthy individual is studied, his/her erythrocytes in capillaries continually change their shape in a synchronized erratic fashion. In this work, the problem of characterizing the cell behavior is studied from the perspective of bounded correlated random walk, based on the assumption that diffractometric data involves both deterministic and stochastic components. The photometric readings are obtained by ektacytometry over several millions of shear elongated cells, using a home-made device called Erythrodeformeter. We have only a scalar signal and no governing equations; therefore the complete behavior has to be reconstructed in an artificial phase space. To analyze dynamics we used the technique of time delay coordinates suggested by Takens, May algorithm, and Fourier transform. The results suggest that on random-walk approach the samples from healthy controls exhibit significant differences from those from diabetic patients and these could allow us to claim that we have linked mathematical nonlinear tools with clinical aspects of diabetic erythrocytes’ rheological properties.

Site mapping and quantitation of O‐GlcNAcylated proteins in diabetic erythrocytes

O‐linked N‐acetylglucosamine (O‐GlcNAc) is a ubiquitous post‐translational modification found on nucleocytoplasmic proteins. This modification is very dynamic and sensitive to cellular nutrients and stress. Cycling of O‐GlcNAc on many proteins can modulate diverse events in cells. Elevated global O‐GlcNAcylation is associated with development of many diseases including neurodegenerative diseases, cancer and diabetes. In diabetic patients, prolonged exposure to high glucose may result in global changes of O‐GlcNAcylation and altered occupancy of O‐GlcNAc on certain proteins.We examined the changes of O‐GlcNAcylation in diabetic red blood cells and site‐mapped O‐GlcNAc on proteins using semi‐quantitative mass spectrometry method. We modified beta‐elimination/Michael addition detection (BEMAD)/mass spectrometry method by adding enrichment steps for O‐GlcNAcylated peptides. This step improved the efficiency of O‐GlcNAc detection. We have identified multiple O‐GlcNAc sites on erythrocytic proteins such as catalase and carbonic anhydrase I and observed site‐specific differential occupancy of O‐GlcNAc. Significant changes of O‐GlcNAcylation of certain proteins/sites will be used for further study to develop a diagnostic tool for diabetes.

Lipid Peroxidation And Erythrocyte Fragility In Poorly Controlled Type 2 Diabetes Mellitus.

Type 2 Diabetes mellitus has been recently found to have evidence of raised inflammatory markers. The chronic inflammation correlates strongly with cardiovascular morbidity markers such as coronary artery disease, stroke and peripheral arterial disease. The chronic inflammation has been linked to the generation of free radicals. The evidence is however inconclusive. Thus there is increased interest in determining the oxidative status of persons with diabetes. This study was carried out to determine if the plasma oxidative stress status is high in diabetics (especially those that are poorly controlled) and to determine the effect on erythrocyte stability. Plasma levels of thiobarbituric acid reacting substances (TBARS), an index of lipid peroxidation, and erythrocyte osmotic stability were determined. These were compared between poorly controlled type 2 diabetics and nondiabetic individuals. The plasma level of TBARS were significantly higher in the plasma of the diabetics: 0.90 +/- 0.09 micromol malondialdehyde (MDA) equivalent L(-1) vs 0.57 +/- 0.02 micromol MDA equivalent L(-1) for control subjects (p=0.002). The diabetic erythrocytes also showed significantly higher fragility: 3.99 +/- 0.37% haemolysis vs 2.11 +/- 0.27% haemolysis for controls (p=0.0004). Our data shows the occurrence of significantly higher oxidative stress level and osmotic fragility of erythrocytes in the cohort of persons with poorly controlled diabetes mellitus.

An altered oxidant defense system in red blood cells affects their ability to release nitric oxide-stimulating ATP

A novel microflow technique is used to demonstrate that a weakened oxidant defense system found in diabetic erythrocytes leads to decreased levels of deformation-induced release of adenosine triphosphate (ATP) from erythrocytes. Addition of an oxidant to rabbit erythrocytes resulted in a 63% decrease in deformation-induced ATP release before eventually recovering to a value that was statistically equivalent to the initial value. Inhibition of glucose-6-phosphate dehydrogenase prevents recovery from the oxidant attack. Finally, results indicated that the ATP release from the erythrocytes of type II diabetics (91 nM +/- 10 nM) was less than half of that measured from the erythrocytes of healthy controls (190 +/- 10 nM). These data suggest that the antioxidant status of erythrocytes is a critical determinant in the ability of these cells to release ATP, a known nitric oxide stimulus.

Protective role of tea catechins against oxidation‐induced damage of type 2 diabetic erythrocytes

1. Oxidative stress is recognized as a major contributing factor for the development of late complications of diabetes. 2. Tea contains polyphenolic compounds (catechins), which have many important biological properties, including strong anti-oxidant activity. 3. The present study was undertaken to evaluate the effect of tea catechins (epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) and epicatechin (EC)) on markers of oxidative stress (malondialdehyde (MDA), reduced glutathione (GSH) and membrane -SH group) in erythrocytes from type 2 diabetics. 4. Oxidative stress was induced in normal and type 2 diabetic erythrocytes by incubating with tert-butyl hydroperoxide (t-BHP). 5. Diabetic erythrocytes have higher MDA and decreased GSH and membrane -SH groups compared with normal erythrocytes. 6. Our results show that tea catechins protect erythrocytes from t-BHP-induced oxidative stress, the effect being more pronounced in diabetic erythrocytes. The relative effectiveness of individual catechins are in the order of EGCG>ECG>EGC>EC. 7. We hypothesise that a higher intake of catechin-rich food by diabetic patients may provide some protection against the development of long-term complications of diabetes.

Purine nucleotides and their metabolites in erythrocytes of streptozotocin diabetic rats

In the present study it was tried to obtain a complete overview of purine nucleotide metabolism in erythrocytes of streptozotocin (STZ) induced diabetes mellitus rats. Erythrocyte levels of the main nucleotides (ATP, ADP, AMP, GTP, GDP, GMP, IMP, NAD+, NADP+), nucleosides (Ado, Guo, Ino) and the base Hyp were measured using the HPLC method. The parameters that can be deduced from their concentrations: TAN, TGN and AEC, GEC expressed by the ratio of high/low energy nucleoside phosphates were calculated. The effects of streptozotocin-induced diabetes on the concentration and metabolism of rat erythrocyte purine and pyridine nucleotides and the activity of Na+, K+-ATPase as well as Ca2+-ATPase were investigated. Increased dephosphorylation of adenine nucleotides (found as the increased concentration of Ado and Hyp and the decrease in AEC value) and the decrease in ATP and TAN and the changes in the concentrations of NAD+ and NADP+ suggest serious purine and pyridine metabolism disruptions in diabetic erythrocytes and decrease in ATPases activity. The observations suggest that purine nucleotide degradation is markedly accelerated in erythrocytes of STZ diabetic rats.

The methaemoglobin forming and GSH depleting effects of dapsone and monoacetyl dapsone hydroxylamines in human diabetic and non-diabetic erythrocytes in vitro

The respective methaemoglobin forming and GSH depleting capabilities of monoacetyl dapsone hydroxylamine (MADDS–NHOH) and dapsone hydroxylamine (DDS–NHOH) were compared in human diabetic and non-diabetic erythrocytes in vitro with a view to select the most potent agent for future oxidative stress and antioxidant evaluation studies. Administration of both metabolites to non-diabetic erythrocytes over the 20 min period of the study resulted in significantly more methaemoglobin formation at all four time points compared with the diabetic erythrocytes ( P<0.0001). At all four time points, significantly more methaemoglobin was formed in response to MADDS–NHOH in non-diabetic cells compared with the effects of DDS–NHOH on diabetic erythrocytes ( P<0.0001). At the 5 and 10 min time points, significantly more methaemglobin was formed in non-diabetic cells in the presence of MADDS–NHOH compared with DDS–NHOH ( P<0.05). At the 5 min time point only, significantly more methaemoglobin was formed in the presence of MADDS–NHOH in diabetic cells compared with that of DDS–NHOH ( P<0.01). However, compared with diabetic control GSH levels, the presence of DDS–NHOH caused a significant depletion in GSH at 5, 10 and 20 min time points in diabetic cells ( P<0.001). In addition, the presence of DDS–NHOH caused a significant reduction in GSH levels in diabetic cells in comparison with those of non-diabetics at the 5, 10 and 20 min, ( P<0.005). DDS–NHOH was also associated with a significant depletion of GSH levels in diabetic cells compared with those of non-diabetic control erythrocytes ( P<0.0001). The presence of MADDS–NHOH in diabetic erythrocytes led to a significant reduction in GSH levels at the 20 min time point compared with those of non-diabetics ( P<0.001), but there were no significant differences at the 5, 10 and 15 min points. Due to its greater GSH-depleting action, DDS–NHOH will be selected for future use in the oxidative stress assessment in diabetic erythrocytes.

Membrane lipids and protein-bound carbohydrates status during the maturation of reticulocytes to erythrocytes in type 2 diabetics

Background: The reticulocyte maturation process is an ideal model for the study of biochemical alterations seen during final stage of erythropoiesis under disease conditions. In this study, determined whether type 2 diabetes has any effect on membrane lipids and protein-bound carbohydrates during the maturation of reticulocytes to erythrocytes. Subjects and methods: Lipids (cholesterol and phospholipids) and protein-bound carbohydrates (hexose, hexosamine and sialic acid) were extracted and estimated in plasma, membrane of reticulocytes and erythrocytes from 20 treated but uncontrolled type 2 diabetic volunteers and age matched controls. Results: Plasma, membranes of reticulocytes and erythrocytes of diabetics showed increase in cholesterol (35.7%, 8.7% and 16.4%); phospholipids (43.4%, 18.8% and 8.2%); hexose (34.1%, 19.3% and 8.2%) and decrease in hexosamine (11.9%, 7.3% and 14.7%); and sialic acid (34.1%, 19.3% and 32.0%) compared to controls. As reticulocytes matured to erythrocytes, cholesterol, phospholipids, hexosamine and sialic acid levels were decreased; C/P ratio and hexose levels were increased in both controls and diabetics. However, these alterations were more intensified in diabetics. Conclusion: These alterations in diabetic patients may indicate the existence of one or both of the following conditions: acceleration of maturation processes and/or decreased red blood cell life span.

電磁気泳動法による糖尿病赤血球膜糖化度測定

本研究では，電磁気泳動法による赤血球膜糖化度測定法を開発した．糖尿病患者の死因の大半は血管障害に起因するものであり，その発症予知が糖尿病治療に重要である．現行の糖尿病の日常検査は，主として早朝空腹時血糖及びグリコヘモグロビンA1c（HbA1c）測定で行われているが，これらの検査法では，糖尿患者の細胞障害及び血管障害程度を評価することはできない．本研究は，それを可能にする方法の開発を目的とした．本法の原理は，赤血球膜表面糖量に相関したホウ酸磁気ビーズが赤血球膜に結合し，赤血球膜に結合した磁気ビーズの数に比例して外部磁力の影響を強く受けるので，その電気泳動度が抑制されるというものであった．よって，赤血球のホウ酸磁気ビーズ結合体の分離は，電気泳動（駆動）と磁気引力（制動）を利用して行った．本研究では，ホウ酸磁気ビーズを自家合成して使用した．磁気ビーズ結合赤血球泳動の至適制動用外部磁力を選択するために，3種の外部磁力（0，300及び850 G）を検討した．その結果，外部磁力の強度（0，300，850 G）に応じて磁気ビーズ結合赤血球の電気泳動による泳動度は制動された．検討した外部磁力（3種）のうち，本研究の目的に適した磁気ビーズ結合赤血球の制動を示したのは，300 Gの磁力であった．赤血球の電気泳動と電磁気泳動との移動像を比較したところ2種類の赤血球（HbA1c 5.4％，11.3％）では，いずれも両極方向への移動度が電気泳動よりも電磁気泳動で減少した．この傾向はHbA1c 11.3％ の赤血球でいっそう顕著に見られた．その理由は，電気泳動法は赤血球表面電荷度の分布を表しているのに対して，電磁気泳動法では赤血球膜糖化度の分布を表しているためである．糖化度（HbA1c＝5.4，7.7，8.6，9.3 及び11.3％）の電磁気泳動への影響を検討したところ，HbA1c値増加につれて磁気ビーズ結合赤血球の両極側への移動距離が共にしだいに減少した．これは，本法は糖尿病高血糖状態に応じて赤血球膜糖付着量の増加を具現化したことを示している．よって，本研究で開発した方法は，血糖状態に応じた赤血球膜糖化度を測定できることが判明した．

The antioxidant status during maturation of reticulocytes to erythrocytes in type 2 diabetics.

Free radical-induced lipid peroxidation has been associated with numerous disease processes including diabetes mellitus. The extent of lipid peroxidation (LPO) and antioxidant defense system [i.e., levels of glutathione (GSH), glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and catalase (CAT)] were evaluated in reticulocytes and erythrocytes of type 2 diabetic males and age-matched controls. Type 2 diabetics have shown increased lipid peroxidation and decreased levels of GSH, GR, GPx, G6PDH, and GST both in reticulocytes and erythrocytes compared to controls, indicating the presence of oxidative stress and defective antioxidant systems in these patients. CAT activity is found to be enhanced in both the reticulocytes and erythrocytes of diabetics, with a greater percentage enhancement in reticulocytes. The extent of increase in lipid peroxidation is greater in erythrocytes compared to reticulocytes in these patients. Furthermore, the maturation of reticulocytes to erythrocytes resulted in decreased GSH and decreased activities of all antioxidant enzymes (except CAT) both in normals and type 2 diabetes individuals, indicating decreased scavenging capacity as reticulocytes mature to erythrocytes. These maturational alterations are further intensified in type 2 diabetics. The present study reveals that the alterations in lipid peroxidation and antioxidant system lean toward early senescence of erythrocytes in type 2 diabetic patients.

Optical bioimaging: from living tissue to a single molecule: imaging and functional analysis of blood flow in organic microcirculation.

Activity of blood cells, erythrocytes, leucocytes, and platelets, in microcirculation was observed by using an intravital microscope and confocal laser scanning microscope connected with an image processing system including fluorescence and phosphorescence emission methods. Dynamic functions of the blood flow were mainly observed in mesentery, brain, and liver tissues of rats. The results are summarized as follows: Deformability of diabetic erythrocytes was significantly lower than that of healthy controls, particularly at high shear rate. The spring constant and Young's modulus of diabetic erythrocytes obviously stiffened, making them hard to deform in the capillary. During hemorrhagic shock and thrombosis, flow velocity and oxygen partial pressure of blood decreased in the brain and liver tissues that can be visualized by using FITC stained erythrocytes and Pd-porphyrin derivative as a pO(2) probe. Platelet adhesion and thrombus formation in the micro-vessels accelerated under the photodynamic reaction; diabetic platelets showed augmented adhesion and aggregation on the vessel wall which was followed by acute thromboembolism. Active oxygen radicals take part in thrombus formation, accompanied with adhesion of the activated leucocytes. Fluorescent dye probes, rhodamine G and acridine orange, are quite useful for visualization of the flow behavior of platelets and leucocytes, respectively.