Geriatric Nutritional Risk Index as a Prognostic Factor for Renal Progression in Patients with Type 2 Diabetes Mellitus

The aim of this study was to evaluate whether the geriatric nutritional risk index (GNRI) is associated with chronic kidney disease (CKD) progression in patients with type 2 diabetes mellitus (DM). In total, 1100 patients with type 2 DM with a follow-up duration > 1 year were included in this longitudinal study. The risk of CKD progression was assessed according to GNRI quartiles. Patients in the lowest GNRI quartile exhibited a significantly lower estimated glomerular filtration rate (eGFR), compared with those in quartile four. Moreover, these patients had poorer glycemic control and lower hemoglobin levels, body mass index, and albumin levels. Additionally, they exhibited a greater annual decline in eGFR. Multivariate logistic regression analysis showed that old age (>60 years), baseline eGFR, the presence of proteinuria, the use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and low GNRI were significantly associated with CKD progression. GNRI may serve as a valuable predictive tool for identifying the risk of adverse renal outcomes in patients with type 2 DM. It may potentially serve as a more feasible measure for assessing the nutritional status of these patients, as well as for predicting their clinical outcomes.

Risk factors for overcorrection of severe hyponatremia: a post hoc analysis of the SALSA trial

Background

Hyponatremia overcorrection can result in irreversible neurologic impairment such as osmotic demyelination syndrome. Few prospective studies have identified patients undergoing hypertonic saline treatment with a high risk of hyponatremia overcorrection.

Methods

We conducted a post hoc analysis of a multicenter, prospective randomized controlled study, the SALSA trial, in 178 patients aged above 18 years with symptomatic hyponatremia (mean age, 73.1 years; mean serum sodium level, 118.2 mEq/L). Overcorrection was defined as an increase in serum sodium levels by >12 or 18 mEq/L within 24 or 48 hours, respectively.

Results

Among the 178 patients, 37 experienced hyponatremia overcorrection (20.8%), which was independently associated with initial serum sodium level (≤110, 110–115, 115–120, and 120–125 mEq/L with 7, 4, 2, and 0 points, respectively), chronic alcoholism (7 points), severe symptoms of hyponatremia (3 points), and initial potassium level (<3.0 mEq/L, 3 points). The NASK (hypoNatremia, Alcoholism, Severe symptoms, and hypoKalemia) score was derived from four risk factors for hyponatremia overcorrection and was significantly associated with overcorrection (odds ratio, 1.41; 95% confidence interval, 1.24–1.61; p < 0.01) with good discrimination (area under the receiver-operating characteristic [AUROC] curve, 0.76; 95% CI, 0.66–0.85; p < 0.01). The AUROC curve of the NASK score was statistically better compared with those of each risk factor.

Conclusion

In treating patients with symptomatic hyponatremia, individuals with high hyponatremia overcorrection risks were predictable using a novel risk score summarizing baseline information.

Effects of the route of erythropoietin administration on hemoglobin variability and cardiovascular events in hemodialysis patients

Introduction

Despite of the routine use of erythropoietin in hemodialysis patients to correct anemia, its administration route's effects on hemoglobin variability and cardiovascular events remain elusive. Herein, we determined different erythropoietin administration routes' effects on hemoglobin variability in hemodialysis patients and the associated factors of hemoglobin variability and cardiovascular events.

Methods

This is a post hoc analysis of a prospective, controlled, randomized, unblinded study with 78 Korean hemodialysis patients receiving intravenous (n = 40) or subcutaneous (n = 38) erythropoietin therapy. We evaluated hemoglobin variability by calculating the frequency of hemoglobin measurements outside the target range during all visits. The high-frequency group was defined by those with hemoglobin variability over the median value (25%) while the low-frequency group was defined by those with hemoglobin variability of <25%.

Results

In this analysis, 37 patients (51.1%) were males, and the mean age was 50.6 ± 12.5 years. The frequency of the value being outside the target hemoglobin range was higher in the subcutaneous group compared to the intravenous group (p = 0.03). The low-frequency group required significantly lower erythropoietin doses compared to the high-frequency group. In the adjusted Cox analysis, the parameter high group was a significant independent risk factor for cardiovascular events (p = 0.03).

Conclusion

The risk out of the target hemoglobin range increased with subcutaneous administration compared with intravenous erythropoietin administration in hemodialysis patients. An increased frequency of the value being outside the target hemoglobin range was also associated with an increased risk of cardiovascular events.

Association between copeptin levels and treatment responses to hypertonic saline infusion in patients with symptomatic hyponatremia: a prospective cohort study

Background

Copeptin is secreted in equimolar amounts as arginine vasopressin, main hormone regulating body fluid homeostasis. A recent study reported a copeptin-based classification of osmoregulatory defects in syndromes of inappropriate antidiuresis that may aid in prediction of therapeutic success. We investigated usefulness of copeptin for differentiating etiologies of hyponatremia and predicting efficacy and safety of hypertonic saline treatment in hyponatremic patients.

Methods

We performed a multicenter, prospective cohort study of 100 inpatients with symptomatic hyponatremia (corrected serum sodium [sNa] ≤ 125 mmol/L) treated with hypertonic saline. Copeptin levels were measured at baseline and 24 hours after treatment initiation, and patients were classified as being below or above median of copeptin at baseline or at 24 hours, respectively. Correlations between target, under correction, and overcorrection rates of sNa within 24 hours/24–48 hours and copeptin levels at baseline/24 hours were analyzed.

Results

Mean sNa and median copeptin levels were 117.9 and 16.9 pmol/L, respectively. Ratio of copeptin-to-urine sodium allowed for an improved differentiation among some (insufficient effective circulatory volume), but not all hyponatremia etiologic subgroups. Patients with below-median copeptin levels at baseline achieved a higher target correction rate in 6/24 hours (odds ratio [OR], 2.97; p = 0.02/OR, 6.21; p = 0.006). Patients with below-median copeptin levels 24 hours after treatment showed a higher overcorrection rate in next 24 hours (OR, 18.00, p = 0.02).

Conclusion

There is a limited diagnostic utility of copeptin for differential diagnosis of hyponatremia. However, copeptin might be useful for predicting responses to hypertonic saline treatment in hyponatremic patients.

Changes in duplex ultrasound parameters during maturation according to arteriovenous access types in incident hemodialysis patients

BACKGROUND

Little is known about the changes in hemodynamic parameters during arteriovenous (AV) access maturation using duplex ultrasound according to radiocephalic fistula (RCF), brachiocephalic fistula (BCF), and AV graft (AVG) in incident hemodialysis (HD) patient. The objective of this study was to evaluate changes and differences in brachial artery flow rate (BAFR) and related parameters affecting maturation by duplex ultrasound in incident HD patients according to access type.

METHODS

This study was an observational study conducted from March 2019 to October 2020. During the study period, 109 incident patients underwent new AV access creation, of which 100 were included in the study. The duplex ultrasound was performed on the day prior to access creation, further, day 1, 2 weeks, and 4 weeks later after access creation in incident HD patients.

RESULTS

Among all the patients, 38 (38%) received BCF, while 26 (26%) underwent RCF. Of the patients with AVG, 18 (50%) had a forearm loop AVG. The overall mean age was 62.2 ± 13.8 years (range, 32-89). The BAFR increased about 6.9 times in the RCF, 17.4 times in the BCF, and 19.5 times in the AVG at day 1. The median BAFR measured on day 1 was 580.4 mL/min for RC, 1029.0 mL/min for BC, and 1133.0 mL/min for AVG. Relative to the values measured in week 4, the BAFR on day 1 was 69.5% in RCF, 90.6% in BCF, and 93.9% in AVG. The acceleration decreased most significantly on day 1(p < 0.05). The acceleration time increased significantly on day 1 (p < 0.05) and beyond during maturation in the RCF and BCF. The BAFR of the RCF had a significantly negative correlation with the pulsatility index. The BAFR of the BCF showed a significantly positive correlation with the systolic and diastolic blood pressure but negatively correlated with pulse rate. The BAFR of the AVG showed a significant positive correlation with the diameter of the outflow vein.

CONCLUSIONS

There were differences in the clinical and duplex parameters during maturation according to access type. The most dramatic changes of duplex parameters were on the day after AV access creation regardless of AV access types. Though RCF had a lower BAFR rate compared to BCF and AVG, it already had a sufficient BAFR required for adequate HD treatment the day after creation. The BAFR of BCF was not different from that of AVG.

Effects of aspirin resistance and mean platelet volume on vascular access failure in hemodialysis patients

BACKGROUND/AIMS

Maintaining the patency of vascular access (VA) in hemodialysis (HD) patients is important and can be life-saving. We investigated the effects of aspirin resistance and mean platelet volume (MPV) on VA failure in HD patients.

METHODS

We enrolled 163 patients on maintenance HD. VA failure was defined as thrombosis or a decrease of > 50% of the normal vessel diameter, as revealed by angiography.

RESULTS

Aspirin resistance was observed in 17 of 109 patients in whom this parameter was measured, and was not significantly associated with VA failure (p = 0.051). The mean MPV was 9.15 ± 0.05 fL. The 163 patients were grouped by the median MPV value (9.08 fL) at baseline; patients with higher MPVs (n = 82) had lower platelet counts (p = 0.002) and albumin levels (p = 0.009). During 34 months of follow-up, 65 VA failures (39.9%) occurred. The Kaplan-Meier curve revealed significant differences between the two groups in terms of cumulative VA failure (54.1% vs. 35.3%, p = 0.018). On multivariate analysis, the MPV (hazard ratio [HR], 1.794; 95% confidence interval [CI], 1.066 to 3.020; p = 0.028), platelet count (HR, 1.003; 95% CI, 1.001 to 1.006; p = 0.01), and smoking status (HR, 1.894; 95% CI, 1.019 to 3.519; p = 0.043) independently predicted VA failure.

CONCLUSION

A high MPV was associated with an increased risk of VA failure, whereas aspirin resistance showed only a weak association. The MPV may predict VA survival in HD patients.

Seropositive rate of the anti-hepatitis A immunoglobulin G antibody in maintenance hemodialysis subjects from two hospitals in Korea

BACKGROUND/AIMS

Hepatitis A virus (HAV) is a self-limiting infectious disease, but 1% of subjects develop fulminant hepatitis. The prevalence of the anti-HAV immunoglobulin G (IgG) antibody in hemodialysis subjects in Korea remains unknown. The purpose of this study was to describe and compare the seropositive rate of anti-HAV antibody among hemodialysis subjects in two hospitals according to age group.

METHODS

A total of 170 hemodialysis subjects were evaluated for the seropositive rate of the anti-HAV IgG antibody and its titer.

RESULTS

Of the 170 maintenance hemodialysis subjects in two hospitals (Kangnam 92 vs. Chuncheon 78), 79 (46.5%) were male. The mean age was 53.2 years old, and 94.1% of the subjects were over 40 years old. The median vintage of hemodialysis was 29.0 months. Anti-HAV antibody was found in 163 subjects (95.9%), with no significant difference between the two areas (Kangnam 97.8% [n = 90] vs. Chuncheon 93.6% [n = 73]). Subjects younger than 40 years old showed a seropositive rate of 50%, while the seropositive rate increased with age for subjects aged 40 or older (p for trend < 0.001). Seropositive subjects from Kangnam showed a higher anti-HAV antibody titer than those from Chuncheon (median: Kangnam 14.2 vs. Chuncheon 11.7). Only age influenced seropositivity. The only factor that influenced the antibody level was the location of hospital (p < 0.001).

CONCLUSION

The seropositive rate of the anti-HAV antibody in hemodialysis subjects was 95%, which is similar to findings in the general population. Active immunization against hepatitis A is strongly recommended for hemodialysis subjects under 40 years of age after anti-HAV testing.

Malnutrition, inflammation, progression of vascular calcification and survival: Inter-relationships in hemodialysis patients

Background and aims

Malnutrition and inflammation are closely linked to vascular calcification (VC), the severity of which correlate with adverse outcome. However, there were few studies on the interplay between malnutrition, inflammation and VC progression, rather than VC presence per se. We aimed to determine the relationship of malnutrition, inflammation, abdominal aortic calcification (AAC) progression with survival in hemodialysis (HD) patients.

Methods

Malnutrition and inflammation were defined as low serum albumin (< 40 g/L) and high hs-CRP (≥ 28.57 nmol/L), respectively. We defined AAC progression as an increase in AAC score using lateral lumbar radiography at both baseline and one year later. Patients were followed up to investigate the impact of AAC progression on all-cause and cardiovascular mortality.

Results

AAC progressed in 54.6% of 97 patients (mean age 58.2±11.7 years, 41.2% men) at 1-year follow-up. Hypoalbuminemia (Odds ratio 3.296; 95% confidence interval 1.178–9.222), hs-CRP (1.561; 1.038–2.348), low LDL-cholesterol (0.976; 0.955–0.996), and the presence of baseline AAC (10.136; 3.173–32.386) were significant risk factors for AAC progression. During the mean follow-up period of 5.9 years, 38(39.2%) patients died and 27(71.0%) of them died of cardiovascular disease. Multivariate Cox regression analysis adjusted for old age, diabetes, cardiovascular history, and hypoalbuminemia determined that AAC progression was an independent predictor of all-cause mortality (2.294; 1.054–4.994).

Conclusions

Malnutrition and inflammation were significantly associated with AAC progression. AAC progression is more informative than AAC presence at a given time-point as a predictor of all-cause mortality in patients on maintenance HD.

Extracellular Fluid/Intracellular Fluid Volume Ratio as a Novel Risk Indicator for All-Cause Mortality and Cardiovascular Disease in Hemodialysis Patients

Background

In hemodialysis patients, fluid overload and malnutrition are accompanied by extracellular fluid (ECF) expansion and intracellular fluid (ICF) depletion, respectively. We investigated the relationship between ECF/ICF ratio (as an integrated marker reflecting both fluid overload and malnutrition) and survival and cardiovascular disease (CVD) in the context of malnutrition-inflammation-arteriosclerosis (MIA) complex.

Methods

Seventy-seven patients from a single hemodialysis unit were prospectively enrolled. The ECF/ICF volume was measured by segmental multi-frequency bioimpedance analysis. MIA and volume status were measured by serum albumin, C-reactive protein (CRP), pulse wave velocity (PWV) and plasma B-type natriuretic peptide (BNP), respectively.

Results

The mean ECF/ICF ratio was 0.56±0.06 and the cut-off value for maximum discrimination of survival was 0.57. Compared with the low ECF/ICF group, the high ECF/ICF group (ratio≥0.57, 42%) had higher all-cause mortality, CVD, CRP, PWV, and BNP, but lower serum albumin. During the 5-year follow-up, 24 all-cause mortality and 38 CVD occurred (18 and 24, respectively, in the high ECF/ICF group versus 6 and 14 respectively in the low ECF/ICF group, P<0.001). In the adjusted Cox analysis, the ECF/ICF ratio nullifies the effects of the MIA and volume status on survival and CVD and was an independent predictor of all-cause mortality and CVD: hazard ratio (95% confidence interval); 1.12 (1.01–1.25) and 1.09 (1.01–1.18) for a 0.01 increase in the ECF/ICF ratio. The degree of malnutrition (albumin), inflammation (CRP), arteriosclerosis (PWV), and fluid overload (BNP) were correlated well with the ECF/ICF ratio.

Conclusions

Hemodialysis patients with high ECF/ICF ratio are not only fluid overloaded, but malnourished and have stiff artery with more inflammation. The ECF/ICF ratio is highly related to the MIA complex, and is a major risk indicator for all-cause mortality and CVD.

Effect of post-voiding urine volume on progression of renal function decline in patients with type 2 diabetes

Diabetic bladder dysfunction (DBD) is a common complication of type 2 diabetes mellitus (T2DM). The association between DBD and progression of diabetic nephropathy has not been clarified. In this study, we investigated the relationship between post-voiding residual urine (PVR) with decline in renal function in patients with type 2 diabetes. This retrospective study included 164 patients at a single center. We collected medical histories and laboratory findings of patients undergoing uroflowmetry from January 1, 2008 to October 30, 2013. Renal function was assessed by calculating the estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) study equation. We evaluated whether greater PVR was a risk factor for faster decline of GFR during a 1-year follow-up. The subjects' mean age was 65±12 years, duration of diabetes 12.8±8.8 years, baseline serum creatinine level 106.1±53.0 μmol/L, and eGFR was 64.6±25.2 mL/min/1.73 m(2). Mean PVR was 69.8±96.3 mL and in 17.7% of subjects, PVR>100 mL. In linear regression analysis, PVR was independently associated with GFR decrease (standardized β coefficient=0.2, P=0.009). Multiple logistic analysis showed that subjects with PVR>100 mL had a 2.8-fold higher risk of an eGFR change during 1 year higher than the median value of all subjects (95% confidence interval, 1.1-6.8; P=0.03). Increased PVR was independently associated with a more rapid decline in renal function in patients with type 2 diabetes.

The association between an abnormal post-voiding urine volume and a lower estimated glomerular filtration rate in patients with type 2 diabetes with no voiding symptoms

BACKGROUND/AIMS

Diabetic cystopathy is a frequent complication of diabetes mellitus. This study assessed the association between the post-voiding residual (PVR) urine volume and diabetic nephropathy in type 2 diabetics with no voiding symptoms.

METHODS

This study investigated 42 patients with type 2 diabetes who were followed regularly at our outpatient clinic between July 1, 2008 and June 30, 2009. No patient had voiding problems or International Prostate Symptom Scores (IPSSs) ≥ 12. An urologist performed the urological evaluations and the PVR was measured using a bladder scan. A PVR > 50 mL on two consecutive voids was considered abnormal, which was the primary study outcome.

RESULTS

The mean patient age was 60 ± 10 years; the IPSS score was 3.7 ± 3.3; and the diabetes duration was 11.9 ± 7.8 years. Seven of the 42 patients (16.7%) had a PVR > 50 mL. The presence of overt proteinuria or microalbuminuria was associated with an increased risk of a PVR > 50 mL (p < 0.01). Patients with a PVR > 50 mL had a significantly lower estimated glomerular filtration rate (eGFR) compared with those with a PVR ≤ 50 mL (59.2 ± 27.1 mL/min/1.73 m(2) vs. 28.7 ± 23.3 mL/min/1.73 m(2); p < 0.001). Multivariate logistic analysis revealed that a lower eGFR (odds ratio, 0.94; 95% confidence interval, 0.88 to 0.99; p = 0.04) was a significant risk factor for a PVR > 50 mL.

CONCLUSIONS

Patients with diabetic nephropathy had a significantly higher PVR and a lower eGFR was associated with an abnormal PVR.

The prevention of contrast-induced nephropathy by simultaneous hemofiltration during coronary angiographic procedures: a comparison with periprocedural hemofiltration

BACKGROUND

Periprocedural (6 h pre- and 24 h post-angiography) hemofiltration appears to effectively prevent contrast-induced nephropathy (CIN) in chronic kidney disease (CKD) patients undergoing coronary angiography. However, this procedure over-uses medical resources, and the cessation of hemofiltration during coronary angiography results in persistent renal injury. In comparison, simultaneous hemofiltration performed only during coronary angiography requires fewer medical resources and can provide instantaneous protection against CIN.

METHODS

Sixty-eight CKD patients (serum creatinine, 2.51±1.15 mg/dL) undergoing coronary angiography were randomized in a 1:2 ratio to receive either periprocedural (n=23) or simultaneous (n=45) hemofiltration. The expected CIN rate was similar for the two groups (41.3% versus 40.0%, p=0.769).

RESULTS

On day 3 after contrast exposure, four and seven patients in the periprocedural and simultaneous groups, respectively experienced CIN (17.4% versus 15.6%, p=0.846). On days 5-30, seven and three patients in the periprocedural and simultaneous groups, respectively experienced CIN (30.4% versus 6.7%, p=0.009). The serum creatinine levels of patients in the periprocedural group transiently decreased on day 1 and persistently increased during days 5-30 compared with the simultaneous group. This difference between the two groups in terms of creatinine levels over time was statistically significant (F statistic=6.830; p=0.001, by ANCOVA). The cost of hemofiltration was doubled in the periprocedural group ($1066±83 versus $504±40, p<0.001).

CONCLUSIONS

Simultaneous hemofiltration provide equal early (day 3) and better late-stage (days 5-30) renal protection against CIN at a significantly lower cost compared with periprocedural hemofiltration.

The effect of a charge control layer on the electroluminescent characteristic of blue and white organic light-emitting diodes

We investigated blue fluorescent organic light-emitting diode (OLED) with a charge control layer (CCL) to produce high efficiency and improve the half-decay lifetime. Three types of devices (device A, B, and C) were fabricated following the number of CCLs within the emitting layer (EML), maintaining the thickness of whole EML. The CCL and host material, 2-methyl-9,10-di(2-naphthyl)anthracene, which has a bipolar property, was able to control the carrier movement with ease inside the EML. Device B demonstrated a maximum luminous efficiency (LE) and external quantum efficiency (EQE) of 9.19 cd/A and 5.78%, respectively. It also showed that the enhancement of the half-decay lifetime, measured at an initial luminance of 1,000 cd/m2, was 1.5 times longer than that of the conventional structure. A hybrid white OLED (WOLED) was also fabricated using a phosphorescent red emitter, bis(2-phenylquinoline)-acetylacetonate iridium III doped in 4,4'-N,N'-dicarbazolyl-biphenyl. The property of the hybrid WOLED with CCL showed a maximum LE and an EQE of 13.46 cd/A and 8.32%, respectively. It also showed white emission with Commission International de L'Éclairage coordinates of (x = 0.41, y = 0.33) at 10 V.

Effect of an organic buffer layer on the stability of zinc oxide thin-film transistors

Compared with other materials, zinc oxide (ZnO) exhibits stability in air, high-electron mobility, transparency and low light sensitivity. We investigated these properties in ZnO thin-film transistors (TFTs) containing a cross-linked poly(vinyl alcohol) (C-PVA) (1:3) buffer layer stacked between the semiconductor and gate dielectric. We measured the impact of this C-PVA layer on gate bias stress. We measured the transfer characteristics of the saturation region to determine the threshold voltage and the field-effect mobility of the transistors. We recorded a threshold voltage of 11.53 V in the ZnO TFTs with the C-PVA buffer layer, the field-effect mobility was 0.2 cm2/Vs. There was a positive shift in the threshold voltage of deltaV(TH) approximately 10 V in response to the application of a gate bias stress of 20 V. The positive shift in the threshold voltage was lower than that in pristine ZnO TFTs. This finding suggests that the shift in threshold voltage was due to reduced charge trapping at the semiconductor-gate dielectric interface. Our report indicates that the organic buffer layer enhanced the stability of ZnO TFTs.

Rhabdomyolysis and acute kidney injury associated with hypothyroidism and statin therapy

Rhabdomyolysis is a syndrome involving the breakdown of skeletal muscle that causes myoglobin and other intracellular proteins to leak into the circulatory system, resulting in organ injury including acute kidney injury. We report a case of statin-induced rhabdomyolysis and acute kidney injury that developed in a 63-year-old woman with previously undiagnosed hypothyroidism. Untreated hypothyroidism may have caused her hypercholesterolemia requiring statin treatment, and it is postulated that statin-induced muscle injury was aggravated by hypothyroidism resulting in her full-blown rhabdomyolysis. Although this patient was successfully treated with continuous venovenous hemofiltration and L-thyroxin replacement, rhabdomyolysis with acute kidney injury is a potentially life-threatening disorder. Physicians must pay special attention to the possible presence of subclinical hypothyroidism when administering statins in patients with hypercholesterolemia.

Semi-transparent a-IGZO thin-film transistors with polymeric gate dielectric

We report the fabrication of semi-transparent a-IGZO-based thin-film transistors (TFTs) with crosslinked poly-4-vinylphenol (PVP) gate dielectric layers on PET substrate and thermally-evaporated Al/Ag/Al source and drain (S&D) electrodes, which showed a transmittance of 64% at a 500-nm wavelength and sheet resistance of 16.8 omega/square. The semi-transparent a-IGZO TFTs with a PVP layer exhibited decent saturation mobilities (maximum approximately 5.8 cm2Ns) and on/off current ratios of approximately 10(6).

Flexible bottom-emitting white organic light-emitting diodes with semitransparent Ni/Ag/Ni anode

We fabricated a flexible bottom-emitting white organic light-emitting diode (BEWOLED) with a structure of PET/Ni/Ag/Ni (3/6/3 nm)/ NPB (50 nm)/mCP (10 nm)/7% FIrpic:mCP (10 nm)/3% Ir(pq)(2) acac:TPBi (5 nm)/7% FIrpic:TPBi (5 nm)/TPBi (10 nm)/Liq (2 nm)/ Al (100 nm). To improve the performance of the BEWOLED, a multilayered metal stack anode of Ni/Ag/Ni treated with oxygen plasma for 60 sec was introduced into the OLED devices. The Ni/Ag/Ni anode effectively enhanced the probability of hole-electron recombination due to an efficient hole injection into and charge balance in an emitting layer. By comparing with a reference WOLED using ITO on glass, it is verified that the flexible BEWOLED showed a similar or better electroluminescence (EL) performance.

Flexible top-emitting organic light-emitting diodes using semi-transparent multi-metal layers

In this paper, the improved device performance of top-emitting organic light-emitting diodes (TEOLEDs) with a thin multi-metal layer stack of nickel/silver/nickel (Ni/Ag/Ni) and aluminum/silver/aluminum (Al/Ag/Al) that were used as the anode and cathode on a flexible substrate is discussed. In particular, Indium-Tin-Oxide (ITO) as an anode electrode has been used recently even though it has some problems for flexible devices. Therefore we suggested that a thin multi-metal layer electrode as a new anode is fabricated instead of ITO anode. It was verified that the ITO-free TEOLEDs showed an enhanced probability of the recombination of the electrons and holes through an improved electron/hole charge balance. We also analyzed the optical and electrical characteristics using the current density, luminance, luminance efficiency, external quantum efficiency (EQE), CIE x, y coordinates, and EL spectra of flexible TEOLED devices were characterized. ITO-free, flexible, green-emitting OLEDs with a low cost and a simple process were demonstrated.

Efficient organic photovoltaic devices by using PEDOT:PSSs with excellent hole extraction ability

We have demonstrated the poly(3-hexyl-thiophene-1,5-diyl) (P3HT):[6,6]-phenyl C61-butyric acid methyl ester (PCBM) bulk heterojunction (BHJ) organic photovoltaic (OPV) devices on various poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) (PEDOT:PSSs). The device with PEDOT:PSS of PH 500 adding 1% dimethyl sulfoxide (DMSO) showed the best performances in term of the fill factor and power conversion efficiency (PCE) than others. The hole extraction ability of PEDOT:PSS is very important to balance between holes and electrons mobility because the carrier mobility of PCBM (approximately 10(-4) cm2/Vs) is higher than that of P3HT (approximately 10(-6) cm2/Vs) in P3HT:PCBM BHJ structure. The optimized BHJ OPV with PEDOT:PSS of PH 500 adding 1% DMSO showed a short-circuit current density of 8.92 mA/cm2 and a PCE of 2.97%, which was nearly increased to 2.5 times than that of control device with PEDOT:PSS of P VP Al 4083.

Bias stress effects on different dielectric surfaces of pentacene thin-film transistors

In this paper, it was demonstrated that pentacene thin-film transistors (TFTs) were fabricated with an organic adhesion layer between an organic semiconductor and a gate insulator. In order to form polymeric film as an adhesion layer, a vapor deposition polymerization (VDP) process was introduced to substitute for the usual spin-coating process. Field effect mobility, threshold voltage, and on/off current ratio in pentacene TFTs with a 15 nm thick organic adhesion layer were about 0.4 cm2/Vs, -1 V, and 10(6), respectively. We also demonstrated that threshold voltage strongly depends on the stress time when a gate voltage has been applied for bias stress test. We suggest that a polyimide adhesion layer fabricated by the VDP method can be applied to realize organic TFTs with long-term stability because of lower threshold voltage shifts due to reduced charge trapping at the interface between the pentacene semiconductor and the polyimide layer.

Effect of expression of genes in the sphingolipid synthesis pathway on the biosynthesis of ceramide in Saccharomyces cerevisiae

Ceramide is important not only for the maintenance of the barrier function of the skin but also for the water-binding capacity of the stratum corneum. Although the exact role of ceramide in the human skin is not fully understood, ceramide has become a widely used ingredient in cosmetic and pharmaceutical industries. Compared to other microorganisms, yeast is more suitable for the production of ceramide because yeast grows fast and is non-toxic. However, production of ceramide from yeast has not been widely studied and most work in this area has been carried out using Saccharomyces cerevisiae. Regulating the genes that are involved in sphingolipd synthesis is necessary to increase ceramide production. In this study, we investigated the effect of the genes involved in the synthesis of ceramide, lcb1, lcb2, tsc10, lac1, lag1, and sur2 on ceramide production levels. The genes were cloned into pYES2 high copy number vectors. S. cerevisiae was cultivated on YPDG medium at 30 degrees Celsius. Ceramide was purified from the cell extracts by solvent extraction and the ceramide content was analyzed by HPLC using ELSD. The maximum production of ceramide (9.8 mg ceramide/g cell) was obtained when the tsc10 gene was amplified by the pYES2 vector. Real time PCR analysis showed that the increase in ceramide content was proportional to the increase in the tsc10 gene expression level, which was 4.56 times higher than that of the control strain.

Impedance spectroscopy of a molecular memory cell with a redox-active component

We report the frequency dependent impedance spectroscopy of an Al/Al2O3/ASA-15 monolayer/Ti/Al molecular memory cell. As a result of comparing the memory cell with a control device that does not contain ASA-15 molecules, we confirmed that its impedance properties were originated from the ASA-15 monolayer. By examining the Cole-Cole plot for the fabricated memory cell, we also found that the response of the memory cell can be explained in terms of an equivalent circuit model with a contact resistance R(s) in series with an impedance Z(ox) at the Al oxide layer and an impedance Z(LB) at the ASA-15 monolayer.

Polymorphism in the promoter region of the klotho gene (G-395A) is associated with early dysfunction in vascular access in hemodialysis patients

BACKGROUND/AIMS

Vascular access dysfunction is an important cause of morbidity and mortality in hemodialysis (HD) patients. Recent studies have shown that a klotho gene mutation is related to endothelial dysfunction, thrombosis, and arteriosclerosis, which are regarded as causes of vascular access dysfunction. We investigated the relationship between the klotho G-395A polymorphism and early dysfunction in vascular access in HD patients.

METHODS

Patients who underwent vascular access operations between 1999 and 2002 were enrolled (n=126). Genotyping was performed by allelic discrimination using a 5'-nuclease polymerase chain reaction assay. Clinical data that could be relevant to access dysfunction were obtained from medical records. Early dysfunction of vascular access was defined as the need for any angioplastic or surgical intervention to correct or replace a poorly or nonfunctioning vascular access within 1 year and at least 8 weeks after initial access placement.

RESULTS

Of the 126 patients, the genotype frequency of G-395A was 72.2% for GG (n=91), 24.6% for GA (n=31), and 3.2% for AA (n=4), and the frequency of minor allele was 0.155. Clinical data were similar between the two groups, divided according to the status of the A allele. Early dysfunction occurred in 34 (27.0%) of patients, but it occurred at a significantly higher rate in A allele carriers (45.7%, 16/35) than in noncarriers (19.8%, 18/91; p=0.003).

CONCLUSIONS

Our results suggest that the klotho G-395A polymorphism could be a risk factor for early dysfunction of vascular access in HD patients.

High-fidelity formation of a molecular-junction device using a thickness-controlled bilayer architecture

The device yield of molecular junctions has become a major issue for the practical application of molecular electronics based on a crossbar system of a metal-molecule-metal (MMM) junction. As the thickness of self-assembled monolayers (SAMs) is typically 1-2 nm, it is difficult to avoid electrical shorts due to the penetration of top metal particles into the SAMs. A simple and effective strategy for the creation of a reliable molecular junction using a thickness-controlled bilayer with a bifunctional heterostructure is presented. In the MMM device, the Au adlayer on the molecular layer is spontaneously formed with deposition of the top Au metals and the sandwiched molecular layer maintains the quality of the SAMs. This method greatly reduces electrical shorts by preventing the diffusion of the top metal electrode and offsetting the surface roughness of the bottom metal electrode, resulting in a device yield of more than 90%.

Erosion of embolization coils and guidewires from the kidney to the colon: delayed complication from coil and guidewire occlusion of renal arteriovenous malformation

Percutaneous transarterial embolization is a useful, nondrastic, valuable, and commonly used therapeutic option for the treatment of renal arteriovenous malformation (AVM). Compared with partial or total nephrectomy, transarterial embolization is more conservative and preserves renal function. However, it has some limitations and complications that could cause renal infarction and progression of hypertension, renal insufficiency, and pulmonary embolism. Large-sized AVM and multiplicity of abnormal vessels also limit the use of the embolization technique. The authors experienced erosion of the coils and guidewires that were used for embolization of renal AVM from kidney to descending colon. Coil embolization is practiced extensively, but a complication such as this does not appear to have been described.

Treatment of Depression and Effect of Antidepression Treatment on Nutritional Status in Chronic Hemodialysis Patients

BACKGROUND

Depression, which is the most common psychological complication in patients with end-stage renal disease (ESRD), has an impact on the clinical outcome and is associated with malnutrition in chronic hemodialysis patients. This study evaluated the effect of antidepression treatment on nutritional status in depressed chronic hemodialysis patients.

METHODS

Sixty-two ESRD patients who underwent dialysis for more than 6 months were interviewed and completed a Beck Depression Inventory assessment. Thirty-four patients who had scores greater than 18 on the Beck Depression Inventory score and met Diagnostic and Statistical Manual of Mental Disorders, 4th Edition criteria for major depressive disorder were selected to receive paroxetine 10 mg/day and psychotherapy for 8 weeks. The remaining 28 patients were assigned to the control group. Change in the severity of depressive symptoms was ascertained by administering the Hamilton Depression Rating Scale. Nutritional status was evaluated by normalized protein catabolic rate, serum albumin and blood urea nitrogen level.

RESULTS

All patients successfully completed 8 weeks of antidepression treatment. Antidepression treatment decreased the severity of depressive symptoms (Hamilton Depression Rating Scale score: 16.6 +/- 7.0 versus 15.1 +/- 6.6, P < 0.01) and increased normalized protein catabolic rate (1.04 +/- 0.24 versus 1.17 +/- 0.29 g/kg/day, P < 0.05), serum albumin (37.3 +/- 2.0 versus 38.7 +/- 3.2 g/l, P < 0.005), and prehemodialysis blood urea nitrogen level (24.3 +/- 5.6 versus 30.2 +/- 7.9 mmol/L, P < 0.001). In the control group, no change was noted during the study period.

CONCLUSION

This study suggests that antidepressant medication with supportive psychotherapy can successfully treat depression and improve nutritional status in chronic hemodialysis patients with depression.

The effects of antidepressant treatment on serum cytokines and nutritional status in hemodialysis patients

The aim of this study was to investigate the effects of antidepressant treatment on serum cytokines and nutritional status in hemodialysis patients. Twenty-eight hemodialysis patients with a depressed mood were given 20 mg of fluoxetine for 8 weeks. The degree of depressive symptoms, the serum levels of interleukin-1beta, interleukin-2, interleukin-6, tumor necrosis factor-alpha, c-reactive protein, and markers of nutritional status were assessed at baseline and after treatment. The outcome was assessed in terms of response to treatment (>50% reduction in the score of the Hamilton depression rating scale). Antidepressant treatment decreased the serum level of interleukin-beta1 in both response and nonresponse groups, and increased the serum level of interleukin-6 only in the response group. At baseline, the level of interleukin-6 in the response group was lower than in the nonresponse group. Antidepressant treatment also increased fat distribution significantly in the response group which might have slightly improved the nutritional status. This study suggests that antidepressant treatment improve depressive symptoms and may affect immunological functions and nutritional status in chronic hemodialysis patients with depression.

Association of depression with malnutrition in chronic hemodialysis patients

BACKGROUND

Depression is the most common psychological complication and may increase mortality in chronic hemodialysis patients. Because depression could be associated with poor oral intake and activation of proinflammatory cytokines that could further increase mortality by malnutrition, we investigated the relation between depression and nutritional status in chronic hemodialysis patients.

METHODS

Sixty-two Korean patients completed the Beck Depression Inventory (BDI) questionnaire, and the diagnosis of depression was confirmed by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for major depressive disorder. Nutritional status was evaluated using serum albumin level, normalized protein catabolic rate, subjective global assessment (SGA), and anthropometric measurement.

RESULTS

Mean BDI score was 22.7 +/- 11.4, and 35 patients (56.5%) had a BDI score greater than 21, which is the suggested cutoff score for the diagnosis of depression for the Korean population. Of 40 patients who had a score higher than 18 on the BDI, 34 patients met DSM-IV criteria for major depressive disorder. BDI score correlated negatively with a variety of nutritional parameters: serum albumin level (r = -0.47; P < 0.001), normalized protein catabolic rate (r = -0.32; P < 0.05), SGA (r = -0.47; P < 0.01), triceps skinfold thickness (r = -0.40; P < 0.05), midarm muscle circumference (r = -0.57; P < 0.01), and body mass index (r = -0.28; P < 0.05). Multiple regression analysis also identified BDI score as an independent determinant for all kinds of nutritional parameters.

CONCLUSION

In patients on chronic hemodialysis therapy, depression is related closely to nutritional status and could be an independent risk factor for malnutrition.

Effects of diabetes, insulin and antioxidants on NO synthase abundance and NO interaction with reactive oxygen species

BACKGROUND

Earlier studies have provided evidence for increased production of reactive oxygen species (ROS) and altered nitric oxide (NO) metabolism in diabetes. This study was intended to explore the effect of type I diabetes and its treatment with insulin alone or insulin plus antioxidant-fortified diet on expression of NOS isoforms and ROS interactions with lipids, glucose and NO.

METHODS

Rats with streptozotocin-induced diabetes were divided into once-daily insulin (ultralente)-treated, insulin plus antioxidant (vitamin E and vitamin C)-treated and untreated groups. After four weeks, plasma malondialdehyde (MDA) and tissue endothelial (eNOS), neuronal (nNOS) NO synthases, carboxymethyllysine (CML) and nitrotyrosine were determined.

RESULTS

The untreated diabetic animals exhibited severe hyperglycemia, elevated blood pressure, increased plasma MDA, high tissue CML and reduced tissue nitrotyrosine denoting enhanced lipid, glucose and protein oxidation but reduced NO oxidation by ROS. This was coupled with significant reduction of eNOS and nNOS expression in renal cortex and eNOS in the left ventricle. Insulin therapy partially lowered blood pressure, tissue CML, plasma glucose and MDA, but significantly raised eNOS expression and nitrotyrosine abundance to supranormal levels. Combined insulin and antioxidant therapies resulted in normalization of blood pressure, plasma MDA, tissue CML and nitrotyrosine without affecting glucose level or NOS expression.

CONCLUSION

Oxidative stress in untreated diabetes is associated with down-regulation of NOS isoforms and increased ROS-mediated oxidation of lipid and glucose, but not NO. Amelioration of hyperglycemia with once-daily insulin administration alone results in up-regulation of NOS isoforms, reduction of lipid and glucose oxidation and increased NO oxidation. However, insulin plus antioxidant supplementation can normalize all three parameters.

Antioxidant therapy potentiates antihypertensive action of insulin in diabetic rats

BACKGROUND

Poorly controlled longstanding diabetes frequently results in sustained hypertension (HTN) which plays a major role in the pathogenesis of diabetic nephropathy. In addition, hyperglycemia, per se, causes a reversible rise in blood pressure (BP) and increases production of reactive oxygen species (ROS). Increased ROS activity may raise BP by promoting inactivation of nitric oxide (NO) and/or nonenzymatic generation of vasoconstrictive prostaglandins from peroxidation of arachidonic acid. Therefore, we hypothesized that antioxidant therapy may enhance the BP-lowering effect of glycemia control with insulin replacement in diabetes.

METHODS

Male Sprague-Dawley rats were rendered diabetic by streptozotocin administration and randomized to untreated, antioxidant-treated (vitamin E-fortified food, tocopherol 5000 U/kg chow and vitamin C-fortified H2O, 1000 mg/L), insulin-treated and insulin plus antioxidant-treated groups. Normal rats fed a regular diet or antioxidant-fortified diet served as controls and monitored for 4 weeks.

RESULTS

The diabetic animals showed marked hyperglycemia, HTN, proteinuria, depressed tissue glutathione level and elevated plasma lipid peroxidation product, malondialdehyde (MDA) denoting increased ROS activity. Insulin therapy alone resulted in significant, but incomplete reduction in BP and plasma MDA but not proteinuria. Antioxidant therapy alone had no effect on the measured parameters in either the diabetic or control animals. However, combined insulin and antioxidant therapies normalized BP, plasma MDA and urinary protein in the diabetic animals. As expected, uncontrolled diabetes resulted in glomerular hyperfiltration which was partially reversed by insulin therapy, but was unaffected by antioxidant therapy.

CONCLUSION

Uncontrolled hyperglycemia in the early phase of diabetes was associated with elevated plasma MDA, HTN and proteinuria. Insulin therapy alone resulted in significant but incomplete reduction of plasma MDA and BP. Antioxidant therapy which was ineffective when given alone, normalized plasma MDA, BP and reduced urinary protein excretion when combined with insulin treatment.

Failure of continuous venovenous hemofiltration to prevent death in paraquat poisoning

Paraquat poisoning is characterized by multiorgan failure and pulmonary fibrosis with respiratory failure. Multiorgan failure with circulatory collapse is a major cause of early death within 3 days of paraquat ingestion. Recent studies suggested that continuous venovenous hemofiltration (CVVH) had a role in the treatment of multiorgan failure by promoting hemodynamic stability. We therefore evaluated the effect of prophylactic CVVH in 80 patients with paraquat poisoning (August 1996 to February 1999). The amount ingested was 2.1 +/- 1.0 mouthfuls (as 20% concentrate). All patients were treated with hemoperfusion (HP; duration, 6.4 +/- 3.0 hours) within 24 hours of ingestion and then randomly assigned to the HP-alone or HP-CVVH group. Forty-four patients underwent HP only, and 36 patients underwent CVVH (duration, 57.4 +/- 31.3 hours; ultrafiltration volume, 40.2 +/- 4.8 L/d) after HP. Although time to death after ingestion was significantly longer in the HP-CVVH than HP group (5.0 +/- 5.0 versus 2.5 +/- 2.1 days; P < 0.05), there was no difference in mortality rates between the two groups (66.7% versus 63.6%; P = 0.82). In the HP group, early circulatory collapse was a major cause of death compared with the HP-CVVH group, in which late respiratory failure was a major cause of death. In conclusion, prophylactic CVVH after HP prevented early death caused by circulatory collapse and prolonged survival time. However, it could not prevent late death caused by respiratory failure and did not provide a survival benefit in acute paraquat poisoning.

Th1/Th2 predominance and proinflammatory cytokines determine the clinicopathological severity of IgA nephropathy

BACKGROUND

IgA nephropathy is one of the most common forms of primary glomerulonephritis in adults. Its pathogenesis is complex. The nature of infiltrating and proliferating cells and of cellular mediators could contribute to the progression of IgA nephropathy towards end-stage renal failure.

METHODS

To evaluate this hypothesis, we attempted to quantify the magnitude of intrarenal gene expression of various cytokines (IL-1 beta, TNF-alpha, IL-6, IL-15, IL-2, IFN-gamma, IL-10) and chemokines (IL-8, RANTES, MCP-1) in 48 renal core biopsy specimens, diagnosed as IgA nephropathy by immunofluorescence microscopy. Semi-quantitative reverse-transcriptase polymerase chain reaction using internal competitors was used for the quantification of gene transcripts.

RESULTS

The expression of intrarenal gene transcripts of various cytokines and chemokines was closely interrelated, but not associated with the pathological grading system. The IFN-gamma/IL-10 ratio was higher in patients with renal dysfunction than in those with normal renal function (P=0.0483). Gene transcript levels of proinflammatory cytokines were related to the amount of proteinuria. In patients with severe glomerular sclerosis, the ratio of IFN-gamma/IL-10 gene transcripts was high (P=0.04). IL-10 gene transcript level was related to the severity of tubulointerstitial damage. The levels of gene expression of IL-10 (P=0.009), IFN-gamma (P=0.03), and TNF-alpha (P=0.005) were related to the degree of mesangial matrix expansion and the extent of intrarenal arteriolar changes correlated with the expression of the IL-8 gene transcript (r=0.43, P=0.004).

CONCLUSIONS

We propose that Th1/Th2 predominance and the level of proinflammatory cytokines could determine the pathogenetic processes and the severity of the clinical manifestations of IgA nephropathy.

The relationship between plasma leptin and nutritional status in chronic hemodialysis patients

Leptin serves an important role in suppressing appetite in mice and is known to be elevated in chronic renal failure (CRF) patients. But clinical significance of leptin as an appetite-reducing uremic toxin, remains to be determined. So we studied the relationship between plasma leptin and nutritional status in 46 chronic hemodialysis (HD) patients. Pre HD leptin was measured and divided by body mass index (BMI) to give adjusted leptin levels. KT/Vurea (K, dialyzer urea clearance; T, duration of HD; V, volume of distribution of urea), C-reactive protein (CRP), plasma insulin and nutritional parameters such as serum albumin, normalized protein catabolic rate (nPCR), subjective global assessment (SGA), BMI and mid-arm muscle circumference (MAMC) were also measured. Mean plasma leptin levels were 8.13+/-2.91 ng/mL (male 3.15+/-0.70; female 14.07+/-6.14, p<0.05). Adjusted leptin levels were positively correlated with nPCR (male r=0.47, p<0.05; female r=0.46, p<0.05), SGA (male r=0.43, p<0.05; female r=0.51, p<0.05) and MAMC (male r=0.60, p<0.005; female r=0.61, p<0.05). They did not correlate with KT/Vurea, serum albumin, hematocrit, bicarbonate, insulin and CRP. Presence of DM and erythropoietin therapy had no effect on leptin levels. These results suggest that leptin is a marker of good nutritional status rather than a cause of protein energy malnutrition in chronic HD patients.