Association between dementia diagnosis at dialysis initiation and mortality in older patients with end-stage kidney disease in South Korea

Background

The prevalence of dementia is 2- to 7-fold higher among patients with end-stage kidney disease (ESKD) than among the general population; however, its clinical implications in this population remain unclear. Therefore, this study aimed to determine whether comorbid dementia increases mortality among older patients with ESKD undergoing newly initiated hemodialysis.

Methods

We analyzed data from the Korean Society of Geriatric Nephrology retrospective cohort, which included 2,736 older ESKD patients (≥70 years old) who started hemodialysis between 2010 and 2017. Kaplan-Meier survival and Cox regression analyses were used to examine all-cause mortality between the patients with and without dementia in this cohort.

Results

Of the 2,406 included patients, 8.3% had dementia at the initiation of dialysis; these patients were older (79.6 ± 6.0 years) than patients without dementia (77.7 ± 5.5 years) and included more women (male:female, 89:111). Pre-ESKD diagnosis of dementia was associated with an increased risk of overall mortality (hazard ratio, 1.503; p < 0.001), and this association remained consistent after multivariate adjustment (hazard ratio, 1.268; p = 0.009). In subgroup analysis, prevalent dementia was associated with mortality following dialysis initiation in female patients, those aged <85 years, those with no history of cerebrovascular accidents or severe behavioral disorders, those not residing in nursing facilities, and those with no or short-term hospitalization.

Conclusion

A pre-ESKD diagnosis of dementia is associated with mortality following dialysis initiation in older Korean population. In older patients with ESKD, cognitive assessment at dialysis initiation is necessary.

Efficacy and cost-effectiveness of darbepoetin alfa once every 4 weeks versus continuous erythropoietin receptor activator once every 4 weeks for anemia correction in patients with chronic kidney disease not on dialysis

Background

For anemia management in patients with chronic kidney disease not on dialysis, darbepoetin alfa (DA), which has a shorter half-life but is more inexpensive than continuous erythropoietin receptor activator (CERA), is preferred in Korea. This study evaluated the efficacy, safety, and cost-effectiveness of once-in-4-weeks DA compared with once-in-4-weeks CERA in patients with chronic kidney disease not on dialysis.

Methods

In this randomized, prospective, non-inferiority study, 40 erythropoiesis-stimulating agent-naïve patients with chronic kidney disease not on dialysis were randomized 1:1 to the DA group and CERA group. They received the study drug once in 4 weeks during 10- or 12-week correction period and 24-week efficacy evaluation period. The primary outcomes were the mean difference in the changes in hemoglobin levels between baseline and efficacy evaluation period and hemoglobin response rates during the correction period. The secondary outcomes included differences in adverse events and costs.

Results

DA was non-inferior to CERA for anemia correction; the mean difference in the change in hemoglobin levels between the groups was -0.070 g/dL (95% confidence interval, -0.730 to 0.590 g/dL). Hemoglobin response rates were 100% with DA and 94.1% with CERA. Adverse events were comparable. The mean cost of DA was approximately one-third that of CERA (34,100 ± 7,600 Korean won/4 weeks vs. 115,500 ± 23,600 Korean won/4 weeks; p < 0.001).

Conclusion

Once-in-4-weeks DA safely corrects anemia in erythropoiesis-stimulating agent-naïve patients with chronic kidney disease not on dialysis and is more cost-effective than once-in-4-weeks CERA.

Importance of dialysis specialists in early mortality in elderly hemodialysis patients: a multicenter retrospective cohort study

The early mortality rate in elderly patients undergoing hemodialysis is more than twice that in young patients, requiring more specialized healthcare. We investigated whether the number of professional dialysis specialists affected early mortality in elderly patients undergoing hemodialysis. This multicenter retrospective cohort study analyzed data from 1860 patients aged ≥ 70 years who started hemodialysis between January 2010 and December 2017. Study regions included Seoul, Gyeonggi-do, Gangwon-do, Daejeon/Chungcheong-do, Daegu/Gyeongsangbuk-do, and Busan/Ulsan/Gyeongsangnam-do. The number of patients undergoing hemodialysis per dialysis specialist was calculated using registered data from each hemodialysis center. Early mortality was defined as death within 6 months of hemodialysis initiation. Gangwon-do (28.3%) and Seoul (14.5%) showed the highest and lowest early mortality rate, respectively. Similarly, Gangwon-do (64.6) and Seoul (43.9) had the highest and lowest number of patients per dialysis specialist, respectively. Relatively consistent results were observed for the regional rankings of early mortality rate and number of patients per dialysis specialist. Multivariate Cox regression analysis-adjusted for previously known significant risk factors-revealed that the number of patients per dialysis specialist was an independent risk factor for early mortality (hazard ratio: 1.031, p < 0.001). This study underscores the growing need for dialysis specialists for elderly hemodialysis patients in Korea.

A Pragmatic Randomized clinical trial: twice-weekly vs. thrice-weekly Incident hemoDialysis in Elderly patients (PRIDE): study protocol

Background

The optimal frequency for hemodialysis in older adults with end-stage kidney disease (ESKD) has not been established. This study aims to investigate whether a twice-weekly dialysis schedule using an incremental approach can reduce hospitalization rates in the elderly with incident dialysis, compared with conventional thrice-weekly dialysis.

Methods

We have designed a pragmatic randomized controlled trial to compare the effects of twice-weekly versus thrice-weekly hemodialysis in 428 ESKD individuals (dropout rate 20%) aged 60 years or older with residual kidney function (urine output, >500 mL/ day). The trial will be conducted across 18 referral hospital-based dialysis centers in Korea. Individual participants will be randomized to either a twice-weekly (with incremental approach) or thrice-weekly dialysis group and will be followed up for 24 months. The primary outcome of the study is all-cause hospitalization rate, while secondary outcomes include dialysis-specific hospitalization rates, mortality, quality of life, frailty, and cost-effectiveness. Participants have the flexibility to transfer to other dialysis centers as needed. The decision to increase dialysis frequency will be made by the treating physicians. The study is ongoing and will be completed in May 2026.

Conclusion

This study will provide valuable insights into the benefits and risks of twice-weekly dialysis with an incremental approach in elderly with residual kidney function compared to thrice-weekly dialysis.

Effect of low-density lipoprotein level and mortality in older incident statin-naïve hemodialysis patients

BACKGROUND

This study aimed to analyze low-density lipoprotein cholesterol (LDL-C) levels and their relationship with mortality in order to identify the appropriate lipid profile for older Korean hemodialysis patients.

METHODS

We enrolled a total of 2,732 incident hemodialysis patients aged > 70 years from a retrospective cohort of the Korean Society of Geriatric Nephrology from 2010 Jan to 2017 Dec, which included 17 academic hospitals in South Korea. Of these patients, 1,709 were statin-naïve, and 1,014 were analyzed after excluding those with missing LDL-C level data. We used multivariate Cox regression analysis to select risk factors from 20 clinical variables among the LDL-C groups.

RESULTS

The mean age of the entire patient population was 78 years, with no significant differences in age between quartiles Q1 to Q4. However, the proportion of males decreased as the quartiles progressed towards Q4 (p < 0.001). The multivariate Cox regression analysis, which included all participants, showed that low LDL-C levels were associated with all-cause mortality. In the final model, compared to Q1, the hazard ratios (95% confidence interval) were 0.77 (0.620-0.972; p = 0.027), 0.85 (0.676-1.069; p = 0.166), and 0.65 (0.519-0.824; p < 0.001) for Q2, Q3, and Q4, respectively, after adjusting for covariates, such as conventional and age-specific risk factors. The final model demonstrated that all-cause mortality increased as LDL-C levels decreased, as confirmed by a restrictive cubic spline plot.

CONCLUSIONS

In older hemodialysis patients who had not previously received dyslipidemia treatment, elevated LDL-C levels were not associated with increased all-cause mortality. Intriguingly, lower LDL-C levels appear to be associated with an unfavorable effect on all-cause mortality among high-risk hemodialysis patients.

Association between physical activity and risk of renal function decline and mortality in community-dwelling older adults: a nationwide population-based cohort study

BACKGROUND

Physical activity (PA) is an important risk factor associated with health outcomes. However, the relationship between PA and kidney function decline in older adults remains unclear. We examined the influence of PA on kidney function decline and mortality in community-dwelling older adults.

METHODS

Adults aged ≥ 65 years with an estimated glomerular filtration rate (eGFR) > 60 mL/min/1.73 m² who had available health checkup data from 2009 to 2010 were included. The cohort was followed annually through December 2015 for anthropometric, sociodemographic, and medical information including outcomes and biennially for laboratory information from the health checkup. We divided these patients into three groups according to self-reported PA (Inactive group: no leisure-time PA, Active group: vigorous activity for at least 80 min/week or a sum of moderate-intensity activity and walking for at least 300 min/week, Low-active group: level of PA between the definitions of the other two groups). Associations between the intensity of PA and death, cardiovascular death, and ≥ 50% eGFR decline were investigated.

RESULTS

Among 102,353 subjects, 32,984 (32.23%), 54,267 (53.02%), and 15,102 (14.75%) were classified into the inactive, low-active, and active groups, respectively. The active group was younger, contained a higher proportion of men, and had higher frequencies of hypertension, diabetes mellitus, drinking, and smoking than the other groups. The active group had significantly lower incidence rates of mortality, cardiovascular mortality, and kidney function decline than the other groups (all p < 0.001). The active group also showed lower all-cause (hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.70-0.82) and cardiovascular mortality (HR, 0.64; 95% CI, 0.53-0.78) and protection against ≥ 50% eGFR decline (HR, 0.81; 95% CI, 0.68-0.97) compared with the inactive group in the fully adjusted Cox proportional hazards regression model.

CONCLUSIONS

High PA was an independent modifiable lifestyle factor for reducing mortality and protecting against declines in kidney function in older adults.

Prediction of Heart Function and Volume Status in End-Stage Kidney Disease Patients through N-Terminal Pro-Brain Natriuretic Peptide

Background and Objectives: N-terminal pro-brain natriuretic peptide (NT-proBNP) is a biomarker used to predict heart failure and evaluate volume status in hemodialysis (HD) patients. However, it is difficult to determine the cutoff value for NT-proBNP in HD patients. In this study, we analyzed whether NT-proBNP helps predict heart function and volume status in HD patients. Materials and Methods: This prospective observational study enrolled 96 end-stage kidney disease patients with HD. All patients underwent echocardiography and bioimpedance spectroscopy (BIS) after an HD session. Overhydration (OH) was measured by BIS. Laboratory data were obtained preHD, while serum NT-proBNP was measured after HD. Interventions for blood pressure control and dry weight control were performed, and NT-proBNP was re-assessed after a month. Results: There was an inverse correlation between NT-proBNP and ejection fraction (EF) (β = −0.34, p = 0.001). OH (β = 0.331, p = 0.001) and diastolic dysfunction (β = 0.226, p = 0.027) were associated with elevated NT-proBNP. In a subgroup analysis of diastolic dysfunction grade, NT-proBNP increased according to dysfunction grade (normal, 4177 pg/mL [2637–10,391]; grade 1, 9736 pg/mL [5471–21,110]; and grades 2–3, 26,237 pg/mL [16,975–49,465]). NT-proBNP showed a tendency toward a decrease in the ‘reduced dry weight’ group and toward an increase in the ‘increased dry weight’ group compared to the control group (ΔNT-proBNP, −210 pg/mL [−12,899 to 3142], p = 0.104; 1575 pg/mL [−113 to 6439], p = 0.118). Conclusions: We confirmed that NT-proBNP is associated with volume status as well as heart function in HD patients.

Effect of shared decision-making education on physicians' perceptions and practices of end-of-life care in Korea

Background

Evidence of the ethical appropriateness and clinical benefits of shared decision-making (SDM) are accumulating. This study aimed to not only identify physicians’ perspectives on SDM, and practices related to end-of-life care in particular, but also to gauge the effect of SDM education on physicians in Korea.

Methods

A 14-item questionnaire survey using a modified Delphi process was delivered to nephrologists and internal medicine trainees at 17 university hospitals.

Results

A total of 309 physicians completed the survey. Although respondents reported that 69.9% of their practical decisions were made using SDM, 59.9% reported that it is not being applied appropriately. Only 12.3% of respondents had received education on SDM as part of their training. The main obstacles to appropriate SDM were identified as lack of time (46.0%), educational materials and tools (29.4%), and education on SDM (24.3%). Although only a few respondents had received training on SDM, the proportion of those who thought they were using SDM appropriately in actual practice was high; the proportion of those who chose lack of time and education as factors that hindered the proper application of SDM was low.

Conclusion

The majority of respondents believed that SDM was not being implemented properly in Korea, despite its use in actual practice. To improve the effectiveness of SDM in the Korean medical system, appropriate training programs and supplemental policies that guarantee sufficient application time are required.

Myostatin/Appendicular Skeletal Muscle Mass (ASM) Ratio, Not Myostatin, Is Associated with Low Handgrip Strength in Community-Dwelling Older Women

Background/Aims: Elevated levels of serum myostatin have been proposed as a biomarker for sarcopenia. Recent studies have shown that elevated level of serum myostatin was associated with physical fitness and performance. This study aimed to examine the significance of myostatin in the association between muscle mass and physical performance in the elderly. Methods: This cross-sectional study is based on the Korean Frailty and Aging Cohort study involving 1053 people aged 70 years or over. Anthropometric, physical performance, and laboratory data were collected. Results: The mean age of the participants was 75.8 years, and 50.7% of them were female. Serum myostatin levels in men (3.7 ± 1.2 vs. 3.2 ± 1.1 ng/mL, p < 0.001) were higher compared with that in women. Serum myostatin level was associated with appendicular skeletal muscle mass (ASM) index and eGFR by cystatin C. Serum myostatin/ASM ratio was associated with handgrip strength in women. Conclusion: Higher serum myostatin levels were related with higher muscle mass and better physical performances in the elderly. Serum myostatin/ASM ratio may be a predictor for physical performance rather than myostatin.

Validation of an international prediction model including the Oxford classification in Korean patients with IgA nephropathy

BACKGROUND

Recently, a new international risk prediction model including the Oxford classification was published which was validated in a large multi-ethnic cohort. Therefore, we aimed to validate this risk prediction model in Korean patients with IgA nephropathy.

METHODS

This retrospective cohort study was conducted with 545 patients who diagnosed IgA nephropathy with renal biopsy in three medical centers. The primary outcome was defined as a reduction in estimated glomerular filtration rate (eGFR) of >50% or incident end-stage renal disease (ESRD). Continuous net reclassification improvement (cNRI) and integrated discrimination improvement (IDI) were used to validate models.

RESULTS

During the median 3.6 years of follow-up period, 53 (9.7%) renal events occurred. In multivariable Cox regression model, M1 (hazard ratio [HR], 2.22; 95% confidence interval [CI], 1.02-4.82; p = .043), T1 (HR, 2.98; 95% CI, 1.39-6.39; p = .005) and T2 (HR, 4.80; 95% CI, 2.06-11.18; p < .001) lesions were associated with increased risk of renal outcome. When applied the international prediction model, the area under curve (AUC) for 5-year risk of renal outcome was 0.69, which was lower than previous validation and internally derived models. Moreover, cNRI and IDI analyses showed that discrimination and reclassification performance of the international model was inferior to the internally derived models.

CONCLUSION

The international risk prediction model for IgA nephropathy showed not as good performance in Korean patients as previous validation in other ethnic group. Further validation of risk prediction model is needed for Korean patients with IgA nephropathy.

P0025BARIATRIC SURGERY MAY REDUCE UPREGULATED EXPRESSION OF FIBROBLAST GROWTH FACTOR 21 AND ANGIOTENSIN-CONVERTING ENZYME 2 IN OBESE PATIENTS

Background and Aims

Recent studies showed that the fibroblast growth factor 21 (FGF21) and angiotensin-converting enzyme 2 (ACE2)/Angiotensin 1-7 (Ang (1-7))/MAS axis of the renin-angiotensin system counteract to the negative role of Ang II in various disease. In this study, we examed FGF21 and ACE2/Ang (1-7) in obesity and its change after bariatric surgery.

Method

We prospectively enrolled obese patient who performed bariatric surgery and age-sex matched healthy volunteers (HV) (n=12 each). We obtained their clinical information and serum samples. Serum FGF-21, Ang II, ACE2, and Ang (1-7) levels were measured by enzyme-linked immunosorbent assay kits. We measured also FGF-21, Ang II, ACE2, and Ang (1-7) 6 months after bariatric surgery in obese patients (n=12).

Results

FGF21, Ang II, and ACE2 levels were significantly higher in obese patients compared with HV (p= 0.045, &lt; 0.001, and 0.020, respectively). FGF21, Ang II, and ACE2 levels were significantly decreased after bariatric surgery (p = 0.002, 0.005, and 0.023, respectively). There was no significant difference in Ang (1-7) levels between obese patients and HV (p = 0.887) (Figure 1). Although Ang (1-7) levels did not change after bariatric surgery (p = 0.480), changes in Ang (1-7) levels were positively correlated with changes in body mass index (BMI) (R2 = 0.580, p = 0.048) (Figure 2).

Conclusion

FGF21 and ACE2 were upregulated in obese patients and they are reduced after bariatric surgery. A decrease in BMI after bariatric surgery could lead to decrease in Ang (1-7).

P0369MINOR GLOMERULAR ABNORMALITIES ARE ASSOCIATED WITH DETERIORATION OF LONG-TERM KIDNEY FUNCTION AND MITOCHONDRIAL INJURY

Background and Aims

Minor glomerular abnormalities (MGAs) are unclassified glomerular lesions indicated by the presence of minor structural abnormalities that are insufficient for a specific pathological diagnosis. The long-term clinical outcomes and pathogenesis have not been examined. We hypothesized that MGAs would be associated with the deterioration of long-term kidney function and increased urinary mitochondrial DNA (mtDNA) copy numbers.

Method

We retrospectively enrolled patients with MGAs, age-/sex-/estimated glomerular filtration rate (eGFR)-matched patients with IgA nephropathy (IgAN), and similarly matched healthy controls (MHCs; n = 49 each). We analyzed the time×group interaction effects of the eGFR and compared mean annual eGFR decline rates between the groups. We prospectively enrolled patients with MGAs, age- and sex-matched patients with IgAN, and MHCs (n = 15 each) and compared their urinary mtDNA copy numbers.

Results

Compared to the MHC group, the MGA and IgAN groups displayed differences in the time×group effects of eGFR (Figure 1), higher mean annual rates of eGFR decline (Table), and higher urinary mtDNA copy numbers (Figure 2); however, these groups did not significantly differ from each other.

Conclusion

The results indicate that MGAs are associated with deteriorating long-term kidney function, and mitochondrial injury, despite few additional pathological changes. We suggest that clinicians conduct close long-term follow-up of patients with MGAs.

Efficacy of low-dose spironolactone on top of angiotensin receptor blockade in patients with glomerulonephritis

Background

Previous studies have shown that aldosterone antagonists have a proteinuria-lowering effect in patients with proteinuria and progressive proteinuric disease not adequately controlled by the use of angiotensin receptor blockers (ARBs). Aldosterone antagonists, in combination with ARBs, might improve proteinuria in patients with glomerulonephritis (GN).

Methods

In the present retrospective study, we evaluated the proteinuria-lowering effect and drug safety of low-dose spironolactone (12.5 mg/day) in 42 patients with GN being treated with an ARB.

Results

Proteinuria decreased from a mean total-protein-to-creatinine (TP/Cr) ratio of 592.3 ± 42.0 mg/g at baseline to 335.6 ± 43.3 mg/g after three months of treatment with spironolactone (P < 0.001). After the initial three months, the mean TP/Cr ratio increased progressively at six, nine, and 12 months; however, it was still less than the baseline value (P = 0.001, < 0.001, and < 0.001, respectively). Although serum Cr levels increased significantly at three and nine months compared with baseline (P = 0.036 and 0.026, respectively), there was no time effect of treatment (P = 0.071). Serum potassium levels tended to increase with time (P = 0.118), whereas systolic and diastolic blood pressures decreased with time (P = 0.122 and 0.044, respectively).

Conclusion

Low-dose spironolactone in combination with an ARB reduced proteinuria in patients with GN, which could represent a novel treatment option in individuals whose proteinuria is not optimally controlled by the use of ARBs alone.

Clozapine Induced Neuroleptic Malignant Syndrome

Neuroleptic malignant syndrome is a rare, but potentially life-threatening adverse event associated with the use of neuroleptic agents. We describe the case of a 47-year-old schizophrenic woman who was treated with clozapine for years. The patient developed acute renal failure with pulmonary edema, and underwent mechanical ventilation and hemodialysis.

The repair of umbilical hernia in cirrhotic patients: 18 consecutive case series in a single institute

Purpose

Traditionally, the surgical repair of umbilical hernia in cirrhotic patients with ascites is avoided because of a significant recurrence rate and perioperative morbidity/mortality. However, recent reports recommend early elective surgery in these patients because surgery-related complications can be reduced with minimally invasive surgery and development of perioperative patient care. The current study was conducted to analyze safety and feasibility of umbilical hernia repairs performed in a single institute.

Methods

A single center retrospective analysis of patients' data was conducted. Eighteen patients with umbilical hernia accompanied by liver cirrhosis underwent hernia repair in the period between 2005 and 2012. The charts of these patients were reviewed and demographic data, postoperative complications, and recurrence were recorded.

Results

Eleven males and seven females with a mean age of 62.9 years were analyzed. Two of the patients were classified as Child's class A, 11 as Child's class B, and five as Child's class C. Four patients underwent emergency surgery because of perforations in the hernia sac in two cases and incarcerated hernias in the other two cases. Of the 18 patients who underwent surgery, four (22%) experienced a recurrence, three (17%) developed edema at the surgical sites, one (5%) experienced hepatic coma, and one (5%) showed postoperative variceal hemorrhage. All of these events occurred after emergency surgery.

Conclusion

In contrast to traditional concepts, early and elective repair of umbilical hernia can be performed easily and safely in cirrhotic patients.

Do physical exercise and reading reduce the risk of Parkinson's disease? a cross-sectional study on factors associated with Parkinson's disease in elderly Chinese veterans

BACKGROUND

The purpose of this study was to investigate risk factors for and factors protecting against Parkinson's disease (PD) in elderly Chinese veterans.

METHODS

Using a database containing detailed information on the health status of the nervous system in elderly Chinese veterans, univariate and multivariate analyses of factors that may be associated with PD were performed. Univariate analysis of qualitative data was done using the Pearson Chi-square and Fisher's exact tests, and the Mann-Whitney U nonparametric test was used for univariate analysis of quantitative data. Multivariate logistic regression analysis was used to identify independent risk factors for and factors protecting against PD in elderly Chinese veterans.

RESULTS

A total of 9,676 elderly Chinese veterans were enrolled, including 228 cases with PD and 183 cases with Parkinson's syndrome, with 9,265 non-PD subjects serving as controls. Age (odds ratio [OR] 1.343, 95% confidence interval [CI] 1.028-1.755) and medical history of essential tremor (OR 1.228, 95% CI 1.081-1.396) were identified as independent risk factors for PD, with age being the most important risk factor. Physical exercise (OR 0.478, 95% CI 0.355-0.643) and reading (OR 0.513, 95% CI 0.357-0.735) were identified as independent factors protecting against PD, and physical exercise showed better protection against PD relative to reading. Smoking, alcohol use, anemia, cerebral trauma, education level, and electromagnetic field exposure showed no association with PD.

CONCLUSION

Physical exercise and reading may be independent factors that protect against PD among elderly Chinese veterans, while advancing age and medical history of essential tremor may be independent risk factors for PD. This study was cross-sectional, so further research is needed to confirm its results.

The decreased expression of peroxisome proliferator-activated receptors delta (PPARdelta) is reversed by digoxin in the heart of diabetic rats

The present study is designed to investigate the role of peroxisome proliferator-activated receptors delta (PPARdelta) in the action of digoxin in diabetic rats showing cardiac hypertrophy. We used Wistar rats to induce diabetes by injection of streptozotocin (STZ-rat) and examined the effect of digoxin on PPARdelta expression in these hyperglycemic rats (STZ-rat) at 10 weeks later. We measured the changes of body weight, water intake, and food intake in three groups of age-matched rats; the vehicle treated normal control (Wistar rats), the vehicle treated STZ-rats, and the digoxin-treated STZ-rats. Cardiac output, heart rate, and blood pressure in addition to plasma insulin or glucose level were also determined. The mRNA and protein levels of PPARdelta were measured using Northern and Western blotting, respectively. Cardiac output, heart rate, and blood pressure were markedly reduced while food intake, water intake, and blood glucose were raised in STZ-rats showing lower body weight and plasma insulin as compared with the vehicle-treated controls. After a 20-day of digoxin treatment, cardiac output was raised in STZ-rats but the diabetic parameters were not modified. The PPARdelta expressions, both mRNA and protein, were markedly elevated in the hearts of STZ-rats by digoxin treatment. The related signals with PPARdelta, such as carnitine palmitoyltransferase 1B (CPT1B), acetyl-coenzyme A, carboxylase alpha (ACC1), fatty acid synthase (FAS), and troponin I, were also raised. The increase of cardiac output by digoxin was reversed by the combined treatment with PPARdelta antagonist GSK0660. Thus, we suggest a new finding that PPARdelta is involved in digoxin induced cardiac inrotropic action.

Voxel sensitivity function description of flow-induced signal loss in MR imaging: implications for black-blood MR angiography with turbo spin-echo sequences

The conditions in which the image intensity of vessels transporting laminar flow is attenuated in black-blood MR angiography (BB-MRA) with turbo spin-echo (TSE) and conventional spin-echo (CSE) pulse sequences are investigated experimentally with a flow phantom, studied theoretically by means of a Bloch equation-voxel sensitivity function (VSF) formalism, and computer modeled. The experiments studied the effects of: a) flow velocity, b) imaging axes orientation relative to the flow direction, and c) phase encoding order of the TSE train. The formulated Bloch equation-VSF theory describes flow effects in two-dimensional (2D)- and 3D-Fourier transform magnetic resonance imaging. In this theoretical framework, the main attenuation mechanism instrumental to BB-MRA, i.e., transverse magnetization dephasing caused by flow in the presence of the imaging gradients, is described in terms of flow-induced distortions of the individual voxel sensitivity functions. The computer simulations predict that the intraluminal homogeneity and extent of flow-induced image intensity attenuation increase as a function of decreasing vessel diameter, in support of the superior image quality achieved with TSE-based BB-MRA in the brain.

Black-blood MR angiography with GRASE: measurement of flow-induced signal attenuation

We investigated the feasibility of performing black-blood MR angiography (MRA) with the gradient and spin-echo (GRASE) pulse sequence. Phantom experiments and human testing were conducted, and the results were compared with those of turbo spin-echo (TSE). We demonstrated that both techniques are able to produce signal suppression of flowing fluid to background level. With fewer radiofrequency (RF)-refocusing pulses, GRASE pulse sequences could serve as an alternative black-blood technique of reduced RF power exposure and shorter scan time. These relative advantages of GRASE may become useful when high-resolution images are taken.

T2-weighted MR imaging of the liver: optimization of hybrid-RARE sequences

The objectives of this study were to optimize T2-weighted hybrid-RARE pulse sequences for clinical MR imaging of the liver, and to compare them to the conventional spin-echo (CSE) sequence. Specifically, the ranges of the echo train length (ETL) and the effective echo time (TEeff) were investigated to optimize image quality and liver-spleen contrast, in healthy volunteers. A total of thirteen volunteers were scanned at 1.5 Tesla with an extensive array of hybrid-RARE scans. The images were analyzed quantitatively with respect to CNR (contrast-to-noise ratio of spleen vs. liver), SNR (signal to noise ratio of the spleen), SIR (signal intensity ratio of liver and spleen) and CDR (contrast difference ratio between the spleen and liver). The images were also analyzed qualitatively with respect to image sharpness, vascular artifacts, ghosting, chemical shift, and truncations. Results of quantitative analysis indicated that CDR and SIR of hybrid-RARE at higher ETL (> 13) were consistently better than both the reference CSE and the lower ETL sequences (p < 0.05) at all TEeff. SNR was slightly inferior for all hybrid-RARE sequences than for the CSE sequence. Image quality for hybrid-RARE sequences with ETL > 13 proved to be consistently better than that for the CSE (TE = 90 ms) with respect to imaging sharpness, vascular artifacts and ghosting artifacts (p < 0.05). In conclusion, the optimized hybrid-RARE sequences with ETL greater than or equal to 13 are capable of producing sharp and relatively artifact free images with the advantage of a much greater acquisition time efficiency.

Assessment of heart wall motion: modified spatial modulation of magnetization for MR imaging

This paper reports a new noninvasive method for detecting a regional myocardial infarction. The method consists of superimposing a magnetization grid onto different image planes of the human heart. In this study the spatial modulation of magnetization (SPAMM) in magnetic resonance imaging was modified to accommodate the use of a conventional clinical magnet. The percentages of circumferential shortening (PCS) and the percentages of wall thickening (PWT) during a cardiac cycle were estimated by measuring the amount of deformation of each grid from the end of the diastole to the end of the systole. A small data base was established on 10 subjects (6 normal volunteers and 4 patients). Patients with regional myocardial infarction, when monitored by the modified SPAMM investigation, showed smaller values of PCS and PWT in the areas where myocardial infarction was diagnosed by catheterization. The amount in decrement was directly proportional to the severity of the regional lesions.

Spectral analysis of radial pulse in patients with acute, uncomplicated myocardial infarction

The aim of this study was to examine the frequency spectrum of arterial pulses in 17 patients with acute, uncomplicated myocardial infarction. Recordings of right radial pulses were taken from these patients immediately after their arrival at the emergency room. This information was considered as baseline data and was monitored at the same time each day for up to 7 days. These serial recordings of radial pulses were then analyzed together with recordings from 3 control groups of patients not suffering from myocardial infarction. These included subjects who underwent coronary arteriography (n = 24), coronary angioplasty (n = 18), and mitral valvuloplasty (n = 13). The method of analysis involved a discrete Fourier transformation of radial pulses recorded from an external pulsation transducer to obtain "power spectra" for pulse waves. There was no significant change in the power spectrum for each of the 3 control groups although significant clinical and hemodynamic improvement was observed in the coronary angioplasty and mitral valvuloplasty patients. In sharp contrast, the intensity of the frequency moduli C2 and C3 in the target group fell on arrival at the emergency room and then gradually increased while the average pulse energy (frequency modulus C0) decreased simultaneously with stable recovery from the acute myocardial infarction. In order to investigate the changes in C2 and C3 in the target group, the effective renal plasma flow (ERPF) was first determined for 10 of the 17 patients using intravenous I-131 labelled iodo-ortho-hippurate. A second reading was taken a week later. Eight of the 10 patients were found to have a relatively "higher" ERPF at the onset of acute myocardial infarction with an average reading of 450.1 +/- 168.9 ml/min, compared with the data obtained a week later (374.1 +/- 130.4 ml/min, p < 0.02). An inverse correlation existed between the percentage of "initial drop" in frequency moduli C2 and C3 in the power spectra of the radial pulses and the percentage of "initially higher" ERPF (r = -0.66 and -0.70, respectively, p < 0.05). It is concluded that there was a specific change in the power spectrum of the radial pulses which were recorded and analyzed noninvasively in patients with acute, uncomplicated myocardial infarction. Changes in the ERPF may exert an influence on the frequency moduli C2 and C3 of the power spectra of the radial pulses after heart attack, suggesting that the aorta and the closely organs may cause coupled oscillation. Theoretically this structure is equivalent to a resonance circuit.

Quantitative analysis of high-frequency components of signal-averaged QRS complex in Chinese patients with acute myocardial infarction. A prospective study for prediction of ventricular tachycardia

A prospective study was undertaken of the high-frequency components of the terminal portion of the QRS complex in 38 Chinese patients with acute myocardial infarction (AMI) (mean age 62 +/- 5.6 years) within the first week after the acute event (5.5 +/- 1.2 days). Another 44 normals served as controls (mean age 57 +/- 9.6 years). The electrocardiogram was averaged at a filter band pass of 80-300 Hz. The low voltage span (LVS) of the signals less than 40 microV in the terminal portion of QRS, the root-mean-square (RMS) voltage (V) of terminal 40 msec of the QRS complex, and the total duration of signal-averaged QRS vector complex were measured in both the normal subjects and patients. The LVS was abnormally prolonged in 16 of 38 patients (42%), and in only 16% of normals (p less than 0.05). The RMS-V was abnormal (less than 25 microV) in 29 of 38 patients (76%), and in only 20% of normals (p less than 0.0005), and the signal-averaged QRS vector complex was abnormal (greater than 120 msec) in 26 of 38 patients (68%), and only 9% of normals (p less than 0.005). There was no significant correlation between any of the signal-averaged parameters, the site of AMI and total creatine kinase (CK) or CK-MB values. The signal-averaged parameters also showed no relationship to either the cardiothoracic (C/T) ratio or the left ventricular ejection fraction, determined by the Tc-99 m pertechnetate first pass blood pool technique. Holter ECG monitoring was performed twice in all AMI patients, at 7 to 18 days after the acute event (12 days average) and 3 weeks after the first recording. There were only four episodes of non-sustained ventricular tachycardia (VT), all during the second monitoring period. Three episodes (10%) occurred in patients with positive late potentials (LPs), defined by an RMS-V less than 25 microV in the terminal portion of QRS vector; one episode (11%) occurred in patients with negative LPs (9 patients). Although the incidence of LPs is significantly higher in patients with an AMI than in normal controls, the LPs detected by body surface signal-averaged ECG did not predict the occurrence of in- and out-of-hospital VTs. Thus, after AMI, Chinese patients may not be as prone to develop VTs as are Caucasians. Furthermore, the appearance of LPs is independent of cardiac size and left ventricular ejection fraction.

Posterior polar cataracts: a predisposition to intraoperative posterior capsular rupture

We performed phacoemulsification or planned extracapsular cataract extraction on posterior polar cataracts in 31 eyes of 22 patients and experienced eight cases of posterior capsular rupture (26%). Capsular rupture occurred during removal of the posterior polar opacity or during cleaning of the posterior capsule after the opacity had been removed. We believe that excessive adherence of the opacity to the posterior capsule and unusual thinness of the capsule predisposed these eyes to posterior capsular rupture.

A noninvasive pre-atrial activity recording by signal averaging using esophageal electrode

A noninvasive method employing the technique of signal averaging has been developed for recording sinoatrial (S-A) activity (pre-P wave). Recordings were obtained in man at the time of right heart catheterization. A bipolar esophageal electrode was utilized to record the prominent P waves that were used for triggering in the averaging process. After summing 150 beats, which had coefficients of correlation 0.97 or larger, deflections of small amplitude (less than 40 microV) were obtained preceding the atrial activity. Direct catheter recordings were also taken for comparison. With the new noninvasive method, the sinoatrial conduction time (SACT) estimated for patients with sick sinus syndrome (SSS) was 106 +/- 24 ms (101 +/- 20 ms for the same group measured directly). The SACT for healthy subjects used as the control group was 55 +/- 18 ms. There was good correlation between the pre-atrial activity recorded noninvasively by the esophageal electrode method and invasively from the direct catheter method. The linear correlation coefficient between these two techniques was 0.89 (P less than 0.001) in 17 patients.

GABAergic ganglion cells in the rabbit retina

The ganglion cells are the output neurons of the retina. There is, however, relatively little known about the neurotransmitters used by these cells. In the present study, ganglion cells identified with a ganglion cell-specific monoclonal antibody (AB5) are shown in separate double-label experiments to be gamma-aminobutyric acid (GABA)-like immunoreactive and to possess a high-affinity uptake mechanism for [3H]GABA accumulation. The localization of these markers of GABA activity to AB5-labelled ganglion cells provides the first definitive evidence for the presence of a classical transmitter in retinal ganglion cells and suggests that GABA may perform a role as a neurotransmitter in these cells.