Investigation of SARS-CoV-2 lineages and mutations circulating in a university-affiliated hospital in South Korea analyzed using Oxford Nanopore MinION sequencing.

OBJECTIVES: Despite the introduction of vaccines, treatments, and massive diagnostic testing, the evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has continued to overcome barriers that had slowed its previous spread. As the virus evolves towards increasing fitness, it is critical to continue monitoring the occurrence of new mutations that could evade human efforts to control them. METHODS: We performed whole-genome sequencing using Oxford Nanopore MinION sequencing on 58 SARS-CoV-2 isolates collected during the ongoing coronavirus disease 2019 pandemic at a tertiary hospital in South Korea and tracked the emergence of mutations responsible for massive spikes in South Korea. RESULTS: The differences among lineages were more pronounced in the spike gene, especially in the receptor-binding domain (RBD), than in other genes. Those RBD mutations could compromise neutralization by antibodies elicited by vaccination or previous infections. We also reported multiple incidences of Omicron variants carrying mutations that could impair the diagnostic sensitivity of reverse transcription-polymerase chain reaction-based testing. CONCLUSION: These results provide an understanding of the temporal changes of variants and mutations that have been circulating in South Korea and their potential impacts on antigenicity, therapeutics, and diagnostic escape of the virus. We also showed that the utilization of the nanopore sequencing platform and the ARTIC workf low can provide convenient and accurate SARS-CoV-2 genomic surveillance even at a single hospital.

Genotypes of Staphylococcus aureus Clinical Isolates Are Associated with Phenol-Soluble Modulin (PSM) Production.

Phenol-soluble modulins (PSMs) are important S. aureus virulence factors that cause cytolysis, mast cell degranulation, and stimulate inflammatory responses. In this study, PSM production by S. aureus clinical isolates was measured by liquid chromatography/mass spectrometry (LC-MS) and correlated with staphylococcal protein A (spa) type and staphylococcal cassette chromosome mec (SCCmec) type. Of 106 S. aureus clinical isolates, 50 (47.2%) corresponded to methicillin-susceptible S. aureus (MSSA) and 56 (52.8%) to methicillin-resistant S. aureus (MRSA). LC-MS analysis revealed no significant difference in average PSMα3, PSMα4, PSMß2, and δ-toxin production between MSSA and MRSA isolates, but PSMα1, PSMα2, and PSMß1 production were higher in MSSA than MRSA. This study demonstrated that average PSMα1-α4, PSMß1-ß2, and δ-toxin production by SCCmec type II strains was significantly lower than the IV, IVA, and V strains. Most of the SCCmec type II strains (n = 17/25; 68.0%) did not produce δ-toxin, suggesting a dysfunctional Agr system. The spa type t111 (except one strain) and t2460 (except one strain producing PSM α1-α4) did not produce PSMα1-α4 and δ-toxin, while average PSM production was higher among the t126 and t1784 strains. This study showed that the genotype of S. aureus, specifically the spa and SCCmec types, is important in characterizing the production of PSMs.

Thymol Reduces agr-Mediated Virulence Factor Phenol-Soluble Modulin Production in Staphylococcus aureus.

Staphylococcus aureus is a major human bacterial pathogen that carries a large number of virulence factors. Many virulence factors of S. aureus are regulated by the accessory gene regulator (agr) quorum-sensing system. Phenol-soluble modulins (PSMs) are one of the agr-mediated virulence determinants known to play a significant role in S. aureus pathogenesis. In the present study, the efficacy of thymol to inhibit PSM production including δ-toxin in S. aureus was explored. We employed liquid chromatography-mass spectrometry (LC-MS) to quantify the PSMsα1-PSMα4, PSMß1 and PSMß2, and δ-toxin production from culture supernatants. We found that thymol at 0.5 MIC (128 µg/mL) significantly reduced the PSMα and δ-toxin production in S. aureus WKZ-1, WKZ-2, LAC USA300, and ATCC29213. Downregulation in transcription by quantitative real-time (qRT) PCR analysis of response regulator agrA and receptor histidine kinase agrC upon 0.5 MIC thymol treatment affirmed the results of LC-MS quantification of PSMs. In silico molecular docking analysis demonstrated the binding affinity of thymol with receptors AgrA and AgrC. Transmission electron microscopy images revealed no ultrastructural alterations (cell wall and membrane) in thymol-treated WKZ-1 and WKZ-2 S. aureus strains. Here, we demonstrated that thymol reduces various PSM production in S. aureus clinical isolates and reference strains with mass spectrometry.

Comparison of peaks in the matrix-assisted laser desorption ionization time-of-flight mass spectrometry spectra of Staphylococcus aureus grown on various blood agar plates.

Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) is routinely used for bacterial identification in clinical laboratories. Bacterial protein expression may differ according to their growth conditions, especially the culture medium composition. We aimed to study the peak variations of Staphylococcus aureus grown on various blood agar plates (BAP), especially phenol-soluble modulin-mec (PSM-mec) peak (m/z 2409) associated with mecA gene conferring methicillin resistance. Methicillin-resistant S. aureus (MRSA) ATCC 43300 and eight clinical MRSA isolates were cultured on various commercial BAPs including tryptic soy agar-based BAPs, Columbia agar-based BAP and in-house BAPs with the addition of yeast extract. Analysis of the MALDI-TOF peaks of S. aureus, cultured on various BAPs, revealed the peak intensities of low-molecular weight proteins to vary depending on the composition of BAPs, especially the presence or absence of yeast extract. Especially, the PSM-mec and delta-toxin peaks showed low intensity for S. aureus ATCC 43300 and clinical isolates. No significant differences were found in the number of peaks, but some peaks had lower intensity, corresponding to the medium containing yeast extract, in low-mass region (< m/z 4000). BAPs based on tryptic soy agar rather than Columbia agar seems to be appropriate for the detection of PSM-mec, a methicillin resistance marker of S. aureus and delta-toxin, an agr function indicator.

Comparative evaluation of Nanopore polishing tools for microbial genome assembly and polishing strategies for downstream analysis.

Assembling high-quality microbial genomes using only cost-effective Nanopore long-read systems such as Flongle is important to accelerate research on the microbial genome and the most critical point for this is the polishing process. In this study, we performed an evaluation based on BUSCO and Prokka gene prediction in terms of microbial genome assembly for eight state-of-the-art Nanopore polishing tools and combinations available. In the evaluation of individual tools, Homopolish, PEPPER, and Medaka demonstrated better results than others. In combination polishing, the second round Homopolish, and the PEPPER × medaka combination also showed better results than others. However, individual tools and combinations have specific limitations on usage and results. Depending on the target organism and the purpose of the downstream research, it is confirmed that there remain some difficulties in perfectly replacing the hybrid polishing carried out by the addition of a short-read. Nevertheless, through continuous improvement of the protein pores, related base-calling algorithms, and polishing tools based on improved error models, a high-quality microbial genome can be achieved using only Nanopore reads without the production of additional short-read data. The polishing strategy proposed in this study is expected to provide useful information for assembling the microbial genome using only Nanopore reads depending on the target microorganism and the purpose of the research.

Long-Range Order Self-Assembly of Conjugated Block Copolymers at Inclined Air-Liquid Interfaces.

Here, we report that long-range order, direction-controlled, ultrathin conjugated polymer films can be formed by the self-assembly of conjugated block copolymers (i.e., poly(3-hexylthiophene)-block-poly(ethylene glycol)) at inclined air-water interfaces. Structure analyses revealed well-aligned nanowire arrays of poly(3-hexylthiophene) with a dramatically increased ordered domain size compared to the polymer films formed on a flat water surface. The improved degree of order was attributed to the flow field created by the enhanced solvent evaporation at the top of the water contact line. Note that it is challenging to prepare such well-ordered and molecularly thin films of conjugated polymers by conventional fabrication methods. The long-range order polymer film showed hole mobility an order of magnitude higher than polymer films formed on a flat interface when implemented as an active layer of field-effect transistor devices. This study demonstrates that a simple interface modification can significantly impact the self-assembly process, structure, and function of polymer films formed at the air-liquid interface.

Rapid Discrimination of Methicillin-Resistant Staphylococcus aureus by MALDI-TOF MS.

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious pathogen in clinical settings and early detection is critical. Here, we investigated the MRSA discrimination potential of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) using 320 clinical S. aureus isolates obtained in 2005-2014 and 181 isolates obtained in 2018. We conducted polymerase chain reactions (PCR) for staphylococcal cassette chromosome mec (SCCmec) typing and MALDI-TOF MS to find specific markers for methicillin resistance. We identified 21 peaks with significant differences between MRSA and methicillin-susceptible S. aureus (MSSA), as determined by mecA and SCCmec types. Each specific peak was sufficient to discriminate MRSA. We developed two methods for simple discrimination according to these peaks. First, a decision tree for MRSA based on six MRSA-specific peaks, three MSSA-specific peaks, and two SCCmec type IV peaks showed a sensitivity of 96.5%. Second, simple discrimination based on four MRSA-specific peaks and one MSSA peak had a maximum sensitivity of 88.3%. The decision tree applied to 181 S. aureus isolates from 2018 had a sensitivity of 87.6%. In conclusion, we used specific peaks to develop sensitive MRSA identification methods. This rapid and easy MALDI-TOF MS approach can improve patient management.

Biofilm Formation by Staphylococcus aureus Clinical Isolates is Differentially Affected by Glucose and Sodium Chloride Supplemented Culture Media.

Staphylococcus aureus (S. aureus) causes persistent biofilm-related infections. Biofilm formation by S. aureus is affected by the culture conditions and is associated with certain genotypic characteristics. Here, we show that glucose and sodium chloride (NaCl) supplementation of culture media, a common practice in studies of biofilms in vitro, influences both biofilm formation by 40 S. aureus clinical isolates (methicillin-resistant and methicillin-sensitive S. aureus) and causes variations in biofilm quantification. Methicillin-resistant strains formed more robust biofilms than methicillin-sensitive strains in tryptic soy broth (TSB). However, glucose supplementation in TSB greatly promoted and stabilized biofilm formation of all strains, while additional NaCl was less efficient in this respect and resulted in significant variation in biofilm measurements. In addition, we observed that the ST239-SCCmec (Staphylococcal Cassette Chromosome mec) type III lineage formed strong biofilms in TSB supplemented with glucose and NaCl. Links between biofilm formation and accessory gene regulator (agr) status, as assessed by δ-toxin production, and with mannitol fermentation were not found. Our results show that TSB supplemented with 1.0% glucose supports robust biofilm production and reproducible quantification of S. aureus biofilm formation in vitro, whereas additional NaCl results in major variations in measurements of biofilm formation.

Binary Self-Assembly of Conjugated Block Copolymers and Quantum Dots at the Air-Liquid Interface into Ordered Functional Nanoarrays.

Controlling the nanoscale morphology of conducting polymer/nanoparticle hybrid films is a highly desired but challenging task. Here, we report that such functional hybrid films with unprecedented structural order can be formed through the self-assembly of conjugated block copolymers and CdSe quantum dots at the air-water interface. The one-step assembly of quantum dots and block copolymers composed of polythiophene and polyethylene glycol (P3HT-b-PEG) at the fluidic interface generated a highly ordered assembly structure of P3HT nanowires and one-dimensional quantum dot arrays. Structure analyses revealed a unique self-assembly behavior and size dependency, which are distinct from the conventional self-assembly of coil-type polymers on solid substrates. Interestingly, hydrophobic quantum dots reside at the interface between P3HT and PEG domains without disrupting the P3HT packing structure, which is advantageous for the optoelectronic properties. Furthermore, large particles bridge the P3HT nanowires at both ends, while small particles decorate each P3HT/PEG interfaces, thus forming tight p-n junctions for a broad size range of nanoparticles. The nanoparticle-incorporated hybrid films showed more than an order of magnitude higher photocurrent and light sensitivity compared to polymer-only films, consistent with the assembly structure with close contact between the organic and inorganic semiconductors.

High blood glucose independent of pre-existing diabetic status predicts mortality in patients initiating peritoneal dialysis therapy.

PURPOSE: Poor glycemic control associates with increased mortality in diabetic (DM) dialysis patients, but it is less well established whether high blood glucose (BG) independent of pre-existing diabetic status associates with mortality in dialysis patients. We assessed factors affecting BG at the start of peritoneal dialysis (PD) and its mortality-predictive impact in Korean PD patients. METHODS: In 174 PD patients (55 % males, 56 % DM), BG, nutritional status, comorbidity (CMD), and residual renal function (RRF) were assessed in conjunction with dialysis initiation. Determinants of BG and its association with mortality after a mean follow-up period of 30 ± 24 months were analyzed. RESULTS: On Cox proportional hazards analysis comprising all patients, old age, high CMD score, presence of protein energy wasting, and low serum albumin (Salb) concentration were independent predictors of mortality but not a high-BG level, while in patients without pre-existing diabetic status, high BG, together with old age and high CMD score, was an independent predictor of mortality. After adjustment for age, CMD score, and Salb, the risk ratio for mortality increased by 12 % per 1 mg/dL increase in BG in the non-DM patients. Patient survival in patients without pre-existing diabetic status with high BG did not differ from DM patients, but the survival of patients with high BG was significantly lower than in patients with low BG. In patients without pre-existing diabetic status, in multiple regression analysis, high BG at initiation of PD associated with high age, high body mass index, and low RRF. CONCLUSIONS: High blood glucose at initiation of PD associated with an increased mortality risk in PD patients without pre-existing diabetic status suggesting that blood glucose monitoring and surveillance of factors contributing to poor glycemic control are warranted in patients initiating PD therapy.

The microfluidic chip module for the detection of murine norovirus in oysters using charge switchable micro-bead beating.

Sample preparation has recently been an issue in the detection of food poisoning pathogens, particularly viruses such as norovirus (NoV), in food because of the complexity of foods and raw fresh materials. Here, we demonstrate a total analytical microfluidic chip module to automatically perform a series of essential processes (cell concentration, lysis (RNA extraction), nucleic acid amplification, and detection) for the fast but sensitive detection of norovirus in oysters. The murine NoV spiked oyster was stomached using a standard method. The supernatant was first loaded into a shape switchable sample preparation chamber consisting of charge switchable micro-beads. Murine NoV, which was adsorbed on microbeads by electrostatic physisorption, was lysed using bead beating. The extracted RNA was transferred to the detection chamber to be amplified using Nucleic Acid Sequence Based Amplification (NASBA). The optimal surface functionality, size, and number of microbeads were achieved for the virus concentration and the stable RNA extraction in the shape-switchable micro-channel. As a result, murine NoV in a single oyster was successfully detected within 4h by the microfluidic chip developed here, and could be directly applied to the large volume environmental sample as well as the food sample.

Mortality predictive role of serum uric acid in diabetic hemodialysis patients.

OBJECTIVES: It is controversial to what extent serum uric acid (SUA) is associated with mortality in patients with chronic kidney disease undergoing hemodialysis (HD). We analyzed the predictive role of SUA in the mortality of diabetic and nondiabetic chronic kidney disease patients starting on maintenance HD therapy. DESIGN AND SUBJECTS: SUA was measured at the initiation of HD therapy in 319 patients (137 females and 193 diabetic patients) with mean age of 60 ± 14 years and mean estimated glomerular filtration rate of 7.5 ± 3.8 mL/min/1.73 m(2). The patients were divided into 2 groups, hyperuricemia (HUA; n = 165) and non-HUA (n = 154) groups based on laboratory limit for normal SUA. Mortality was recorded during 31.5 ± 24.8 months. RESULTS: Among the 193 diabetic patients, but not among the whole group of 319 patients, survival was significantly lower in HUA than in non-HUA patients. Among diabetic patients 2-year patient survival was worse in patients with HUA and cardiovascular disease (CVD; 52.3%; n = 30) than in non-HUA patients with CVD (81.1%; n = 36), HUA without CVD (88.6%; n = 62), and non-HUA without CVD (93.9%; n = 65). Cox analysis in all 319 patients showed that, old age, CVD, other comorbidity, and low serum albumin but not high SUA predicted mortality. Among diabetic patients, predictors of increased mortality risk were old age, CVD, other comorbidity but also high SUA with adjusted hazard ratio of 1.12 (95% confidence interval 1.02-1.22) per 1 mg/dL increase in SUA. In diabetic patients with HUA and CVD, adjusted hazard ratio for mortality was 5.98 times that of diabetic non-HUA patients without CVD. CONCLUSIONS: High SUA is associated with poor survival in diabetic patients undergoing HD but not in nondiabetic patients undergoing HD. High SUA was found to be a risk marker especially in diabetic HD patients with concurrent CVD.

Effect of preoperative warming during cesarean section under spinal anesthesia.

BACKGROUND: Postoperative hypothermia and shivering is a frequent event in patients during cesarean section under spinal anesthesia. We assessed the effect of preoperative warming during cesarean delivery under spinal anesthesia for prevention of hypothermia and shivering. METHODS: Forty five patients undergoing elective cesarean section were randomly assigned to three groups. Group F received warmed intravenous fluid (40℃). Group A patients were actively warmed by forced air-warming. Group C was the control group. Forced air-warming and warmed fluid was maintained for the 15 min preceding spinal anesthesia. Core temperature (tympanic membrane) and the skin temperature of arm and thigh were measured and shivering was graded simultaneously. RESULTS: The core temperature at 45 min decreased less in Groups F and A than Group C (-0.5℃ ± 0.3℃ vs -0.6℃ ± 0.4℃ vs -0.9℃ ± 0.4℃, respectively; P = 0.004). The arm temperature at 15 min and 30 min exhibited a greater increase in Group A than Group F and Group C (P = 0.001 and P = 0.012, respectively). Leg temperature increased similarly among the three groups. The incidence of shivering was significantly less in Group A and Group F than Group C (20%, 13.3%, and 53.3%, respectively; P = 0.035). CONCLUSIONS: Preoperative forced air-warming and warmed fluid prevents hypothermia and shivering in patients undergoing elective cesarean delivery with spinal anesthesia.

Nano barcoding cell-based biosensor using fluorophor-embedded silica nanotubes.

A simple and reliable drug screening method was developed using peptide hydrogel cell beads coded by quantum dot-embedded silica nanotubes. Very long silica nanotubes were fabricated upon a nanoporous alumina template using sol-gel techniques. The physical shapes of the nanotubes were measured by TEM (Transmission Electron Microscope). Green and red quantum dots embedded in silica nanotubes were applied to peptide hydrogel cell beads as coding materials. This was confirmed by confocal microscopy that examined fluorescence levels and quantum dot shapes. The peptide hydrogel cell beads coded with silica nanotubes were loaded into a PDMS single chamber in order to assess the effect of doxorubicin on HMEC and MCF-7 cells, which was measured in hydrogel cell beads by live and dead cell staining using coding materials. As a result, MCF-7 cancer cells were more affected by doxorubicin than HMEC; however, doxorubicin induced HMEC cell death at a relatively high concentration (> 5 microg/ml).

Causes of poor appetite in patients on peritoneal dialysis.

Anorexia is common in patients with chronic kidney disease and is a main contributor to the high prevalence of protein-energy wasting in them. The peritoneal dialysis (PD) procedure may further impair appetite by causing abdominal discomfort and also through the absorption of the osmotic agent and other factors. An increased peritoneal solute transport rate has been linked to protein-energy wasting and also to the malnutrition, inflammation, and atherosclerosis syndrome, which has been associated to poor appetite and plays a role in most premature deaths in these patients. The pathogenesis of these associations is unclear. In this review, we discuss the effect of PD, in particular, PD solutions, inflammation, and increased peritoneal solute transport rate, on appetite. We also describe strategies to increase appetite in PD patients.

The relationship between symphysis-fundal height and intravenous ephedrine dose in spinal anesthesia for elective cesarean section.

BACKGROUND: A decreased lumbosacral subarachnoidal space volume is a major factor in the cephalad intrathecal spread of local anesthetics in term parturients and their subarachnoidal space is decreased due to the compressive effect of huge uteri. Therefore, they show a higher level of sensory block and hypotensive episodes. The purpose of this study is to investigate whether the symphysis-fundal height (SFH) correlates with the highest sensory level and the amount of ephedrine administered under spinal anesthesia. METHODS: Fifty-two uncomplicated parturients who consented to spinal anesthesia for elective cesarean section were studied. The SFH of all parturients had been measured just before the spinal anesthesia administered by one person. Hyperbaric bupivacaine with fentanyl 20 µg, was administered for spinal anesthesia. The amount of 0.5% bupivacaine was adjusted according to the patient's height and weight. The level of sensory block and the amounts of ephedrine to treat hypotension, nausea and vomiting were assessed. Linear regression and correlation analysis were applied to analyze the data. RESULTS: According to the results of correlation analysis, there was no significant correlation between the level of sensory block and SFH. There were statistically significant positive correlations between the amount of ephedrine administered due to hypotension and SFH. CONCLUSIONS: In term parturients choosing elective cesarean section, the SFH is not correlated with the sensory level of spinal anesthesia, but is correlated with the amount of ephedrine administered during spinal anesthesia.

Risk factors for mortality in diabetic peritoneal dialysis patients.

BACKGROUND: It is well established that the survival rate of diabetic end-stage renal disease patients remains the lowest among all primary diagnoses probably because of higher prevalence of cardiovascular diseases (CVD) associated with diabetes. This study was designed to evaluate the impact of CVD and other risk factors individually or in combination on mortality in diabetic peritoneal dialysis (PD) patients. METHODS: In a retrospective study, 213 incident PD patients [118 had diabetes mellitus (DM), 94 were female, mean age 55 ± 13 years] underwent initial assessment of nutritional status, comorbid disease (CMD) survey, residual renal function (RRF), dialysis adequacy and peritoneal transport characteristics at a mean of 9 days (range, 3-24 days) after start of PD and were then followed for 30 ± 24 months (range, 3-115 months). Of 213 patients, 154 patients were reassessed after a mean of 11 months (range, 6-19 months). Nutritional status was assessed by subjective global assessment and other methods. CMD was graded by Davies index and included DM, CVD, liver disease and respiratory disease. RESULTS: On Kaplan-Meier analysis, patient survival was significantly lower in female DM patients compared to other groups. The 3-year patient survival rate was 46, 70, 82 and 83% for female DM, male DM, male non-DM and female non-DM, respectively (P = 0.003). On Cox proportional hazards multivariate analysis including all patients, old age, presence of CVD or protein-energy wasting (PEW), low serum albumin concentration and low RRF were independent predictors of mortality but not DM per se or female gender. In DM patients, old age, female gender, presence of CVD or PEW and low RRF were independent predictors of mortality while old age was the only risk factor in non-DM patients. After adjustment for age, gender and RRF, DM patients with both CVD and PEW had a risk of mortality that was 3.3 times that of DM patients without CVD and PEW. In DM patients without CVD and PEW, patient survival was not different from that of non-DM patients without CVD and PEW. CONCLUSIONS: DM per se was not a risk factor for mortality in this group of PD patients. Instead, the higher mortality rate in diabetic PD patients, in particular among female patients, was mainly attributable to concurrent morbidity such as CVD and PEW, together with low RRF.

Morphological investigations of cells that adhered to the irregular patterned polydimethylsiloxane (PDMS) surface without reagents.

Polydimethylsiloxane (PDMS) surface consisting irregular pattern was investigated to develop cell-based biochip using PDMS. PDMS surface was modified with nano- and micro-combined patterns using surface deformation technology. Hydrophobicity of nano-patterned PDMS surface was sustained. Nevertheless it has irregular patterns consisting of micro- and nano-patterns. According to atomic force microscopy (AFM), scanning electron microscopy (SEM) and confocal microscopy results by immunostaining method, human mammary epithelial cells (HMEC) adhered well on irregularly patterned surface without any reagents such as gelatin and collagen, compared to commercial culture dish. It implies PDMS material can be utilized as template for cell-based biochip without any reagents.

Optimal use of peritoneal dialysis in patients with diabetes.

The survival of patients with end-stage renal disease (ESRD) resulting from diabetes continues to improve, but the survival rate among diabetic ESRD patients remains the lowest among all primary diagnoses probably because of the higher prevalence of cardiovascular comorbidity associated with diabetes. Diabetes, age, and comorbidity all significantly modify the effect of treatment modality on patient survival. As compared with hemodialysis (HD), peritoneal dialysis (PD) offers an equal or lower risk of death across all subgroups during the first 1-2 years of dialysis. The association of PD with better outcomes than are seen with HD is probably a result of a lower prevalence of infections and congestive heart failure and better preservation of residual renal function (RRF) in PD patients. Use of angiotensin converting-enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) helps to preserve RRF in ESRD patients and to maintain peritoneal membrane integrity longer in PD patients. Antioxidants can also support preservation of peritoneal membrane function. Peritoneal dialysis should be the initial modality of dialysis in all ESRD patients. Older patients (age > or = 45 years) with diabetes and patients without diabetes may switch to HD or receive a kidney graft in 1-2 years' time; younger patients (age < 45 years) with diabetes may stay on PD longer. Use of ACEI and ARB or antioxidants can help to maintain peritoneal membrane function longer.

Impact of incremental risk factors on peritoneal dialysis patient survival: proposal of a simplified clinical mortality risk score.

BACKGROUND/AIM: Peritoneal dialysis (PD) patient survival is influenced by many factors and there is no consensus on the relative importance of these predictors, independently or combined. This study was designed to evaluate how these independent factors, alone or in various combinations, may influence PD patient survival. METHODS: A peritoneal equilibration test, subjective global assessment (SGA), and comorbid diseases (CMD) were assessed. RESULTS: On multivariate analysis, age (>60 years), CMD, malnutrition, and low RRF (