Correlation between peripheral venous and arterial blood gas measurements in patients admitted to the intensive care unit: A single-center study

Background

The objective of this study was to examine the correlation between arterial blood gas (ABG) and peripheral venous blood gas (VBG) samples for all commonly used parameters in patients admitted to a medical intensive care unit (ICU).

Methods

A single-center, prospective trial was carried out in a medical ICU in order to determine the level of correlation of ABG and peripheral VBG measurements. A maximum of five paired ABG–VBG samples were obtained per patient to prevent a single patient from dominating the data set.

Results

Regression equations were derived to predict arterial values from venous values as follows: arterial pH=−1.108+1.145×venous pH+0.008×PCO₂−0.012×venous HCO₃+0.002×venous total CO₂ (R²=0.655), arterial PCO₂=88.6−10.888×venous pH+0.150×PCO₂+0.812×venous HCO₃+0.124×venous total CO₂ (R²=0.609), arterial HCO₃=−89.266+12.677×venous pH+0.042×PCO₂+0.675×venous HCO₃+0.185×venous total CO₂ (R²=0.782). The mean ABG minus peripheral VBG differences for pH, PCO₂, and bicarbonates were not clinically important for between–person heterogeneity.

Conclusion

Peripheral venous pH, PCO₂, bicarbonates, and total CO₂ may be used as alternatives to their arterial equivalents in many clinical contexts encountered in the ICU.

Treatment results of post-operative radiotherapy in patients with salivary duct carcinoma of the major salivary glands

OBJECTIVE

Salivary duct carcinoma (SDC) is a rare malignancy of high-grade pathological type. We evaluated clinical outcomes and prognostic factors in 35 patients with SDC treated post-operatively with adjuvant radiation.

METHODS

We retrospectively assessed overall survival, locoregional control and disease-free survival in 35 patients with SDC of the major salivary glands who underwent surgery and were subsequently treated with radiotherapy. The evaluated prognostic factors included gender, age, symptom duration, tumour site, tumour size, TNM classification, and the following pathological features: perineural invasion, lymphovascular invasion, extraparenchymal invasion and resection-margin status.

RESULTS

Of the 35 patients, 30 (85.7%) were male. Median age at initial diagnosis was 62 years (range 38-75 years). The parotid gland was the main site affected in 22 patients (62.9%). 18 patients (51.5%) had pathological T3/T4 tumours, and 26 (74.3%) showed pathological nodal involvement. Actuarial 5-year locoregional control, disease-free survival and overall survival rates were 63.3%, 47.4% and 55.1%, respectively. The cause-specific death rate was 31.4% (n=11). Pathological nodal involvement was correlated with distant metastasis (p=0.011). Lymphovascular invasion was significantly prognostic for distant metastasis-free survival (p=0.049), locoregional control (p=0.012) and overall survival (p=0.003) in a Cox proportional hazard model, whereas perineural invasion was only significantly prognostic for overall survival (p=0.005).

CONCLUSIONS

Surgery and post-operative radiotherapy were effective for locoregional control. Lymphovascular invasion and perineural invasion were significant prognostic factors in patients with SDC.

Outcomes of patients with end-stage renal disease (ESRD) under chronic hemodialysis requiring continuous renal replacement therapy (CRRT) and patients without ESRD in acute kidney injury requiring CRRT: a single-center study

In most continuous renal replacement therapy (CRRT) studies, end-stage renal disease (ESRD) patients were excluded and the outcomes of patients with ESRD treated with chronic hemodialysis (HD) were unknown. The purposes of this study were to (1) evaluate short-term patient survival and (2) compare the survival of conventional HD patients needing CRRT with the survival of non-ESRD patients in acute kidney injury (AKI) requiring CRRT. We evaluated adults (>18 years) requiring CRRT who were treated in the intensive care unit (ICU) at Kosin University Gospel Hospital from January 1, 2009 to December 31, 2010. A total of 100 (24 ESRD, 76 non-ESRD) patients underwent CRRT during the study period. Patients were divided into two major groups: patients with ESRD requiring chronic dialysis and patients without ESRD (non-ESRD) with AKI. We compared the survival of conventional HD patients requiring CRRT with the survival of non-ESRD patients in AKI requiring CRRT. For non-ESRD patients, the 90-day survival rate was 41.6%. For ESRD patients, the 90-day survival rate was 55.3%. Multivariate Cox proportional hazards analyses demonstrated that conventional HD was not a significant predictor of mortality (hazard ratio [HR]: 0.334, 95% confidence interval [CI]: 0.063-1.763, P = 0.196), after adjustment for age, gender, presence of sepsis, APACHE score, use of vasoactive drugs, number of organ failures, ultrafiltration rate, and arterial pH. The survival rates of non-ESRD and ESRD patients requiring CRRT did not differ; ESRD with conventional HD patients may be not a significant predictor of mortality.

Coexistence of fibrillary glomerulonephritis in a patient with multiple myeloma

A 71-year-old man was admitted to our hospital for two weeks due to edema in both legs. A bone marrow aspiration test confirmed a diagnosis of multiple myeloma. The result of the patient's renal biopsy showed fibrillary glomerulonephritis (FGN). FGN is a rare form of glomerulopathy that is diagnosed using electron microscopy when deposits of amyloid-like fibrils are observed on the mesangium and microvascular wall. These fibrils do not respond to Congo red staining and are generally 12-30 nm in diameter. This is a report of an unusual case of fibrillary glomerulonephritis in a patient with multiple myeloma.

Effects of silver nanoparticles on biological nitrogen removal processes

The effects of silver (Ag) nanoparticles (NPs) on activated sludge in a biological nitrogen removal (BNR) process were investigated under aerobic and anoxic conditions. We show that nitrification was more vulnerable to Ag NPs exposure than denitrification at the same Ag NPs concentration. In continuous operation of the BNR process, a higher inhibitory effect on nitrification was attributed to a smaller size of Ag NPs. About 70-90% of the Ag NPs supplied were embedded in the sludge matrix but 10-30% of the Ag NPs remained in the supernatant. This indicates that significant amounts of Ag NPs could be discharged from wastewater treatment plants and potentially impact on aquatic ecosystems.

Relationship of serum bilirubin concentration to kidney function and 24-hour urine protein in Korean adults

Background

The relationships among serum bilirubin concentration, kidney function and proteinuria have yet to be fully elucidated, nor have these relationships been investigated in Korean adults.

Method

We retrospectively reviewed the medical records of Korean adults who were evaluated at Kosin University Gospel Hospital (Busan, Republic of Korea) during a five-year period from January 2005 to December 2009. We evaluated the relationships among serum bilirubin concentration, estimated glomerular filtration rate (eGFR) and 24-hour urinary protein excretion in a sample of 1363 Korean adults aged 18 years or older.

Results

The values of eGFR <60 mL/min/1.73 m² and 24-hour urine albumin ≥150 mg/day were observed in 26.1% (n = 356) and 40.5% (n = 553) of subjects, respectively. Fasting glucose levels ≥126 mg/dL were observed in 44.9% (n = 612) of the total sample. After adjustment for potential confounding factors including demographic characteristics, comorbidities and other laboratory measures, total serum bilirubin was positively associated with eGFR and negatively associated with proteinuria both in the whole cohort and in a subgroup of diabetic individuals.

Conclusions

To our knowledge, this is the first hospital-based study specifically aimed at examining the relationships among serum total bilirubin concentration, 24-hour urine protein and kidney function in Korean adults. We demonstrated that serum total bilirubin concentration was negatively correlated with 24-hour urine protein and positively correlated with eGFR in Korean non-diabetic and diabetic adults.

The influence of chronic renal failure on the spectrum and antimicrobial susceptibility of uropathogens in community-acquired acute pyelonephritis presenting as a positive urine culture

Background

The role of chronic renal failure (CRF) in the antimicrobial resistance of uropathogens in patients with community-acquired acute pyelonephritis (APN) remains poorly understood.

Method

We performed a retrospective analysis of 502 adults (54 men, 448 women; mean age 61.7 ± 16.0 years, range 18-98 years) who were treated for community-acquired APN at Kosin University Gospel Hospital (Busan, Republic of Korea) during a ten-year period (January 2000 to December 2009). We evaluated the spectra and antimicrobial susceptibility profiles of uropathogens in CRF and non-CRF patients with community-acquired APN that presented as a positive urine culture.

Results

The 502 adult subjects were classified as either non-CRF APN patients (336 patients, 66.9%) or CRF APN patients (166 patients, 33.1%) according to their estimated glomerular filtration rate. No significant differences in the sensitivity of E. coli to a third cephalosporin, aminoglycoside (except gentamycin), or ciprofloxacin were observed between non-CRF and CRF patients.

Conclusions

In our series of patients with community-acquired APN that initially presented as a positive urine culture, CRF did not influence the isolation rates of different uropathogens or their patterns of susceptibility to antimicrobials.

Application of PTFE membrane for ammonia removal in a membrane contactor

The feasibility of a membrane contactor system for ammonia removal was studied. The mass transfer coefficient was used to quantitatively compare the effect of various operation conditions on ammonia removal efficiency. Effective removal of ammonia was possible with a Polytetrafluoroethylene (PTFE) membrane contactor system at all tested conditions. Among the various operation parameters, contact time and solution pH showed significant effect on the ammonia removal mechanism. The overall ammonia removal rate was not affected by influent suspended solution concentration unlike other pressure driven membrane filtration processes. Also the osmotic distillation phenomena which deteriorate the mass transfer efficiency can be minimized by preheating of influent wastewater. A membrane contactor system can be a possible alternative to treat high strength nitrogen wastewater by optimizing operation conditions such as stripping solution flow rate, influent wastewater temperature, and influent pH.

Fate of nitrogen species in nitrate reduction by nanoscale zero valent iron and characterization of the reaction kinetics

This study investigates the fate of nitrogen species during nitrate reduction by nanoscale zero valent iron (NZVI) as well as the related kinetics. The NZVI used for the experiments was prepared by chemical reduction without a stabilizing agent. The pseudo first order kinetic constant of nitrate reduction at 30 degrees C with an NZVI/nitrate ratio of 1.25:1, which were the reference conditions of this study, was 4.08 h(-1) (R(2)=0.955). A nitrogen mass balance was established by quantitative analysis of aqueous-phase and gas-phase nitrogen species. The results confirm that the nitrate was converted to ammonium ion, that ammonia stripping subsequently occurred under a strong alkaline condition, and that the total amount of aqueous nitrogen was consequently reduced. The nitrate reduction rate also increased with a lower pH and a higher temperature when microscale ZVI was used. However, in contrast to the reaction by microscale ZVI, the nitrate reduction rate by NZVI was higher for an unbuffered condition, possibly due to the abundance of surface atoms and the smaller size.

Measurement of kidney volume with multi-detector computed tomography scanning in young Korean

PURPOSE

Kidney volume is regarded as the most precise indicator of kidney size. However, it is not widely used clinically, because its measurement is difficult due to the complex kidney shape. We attempted to evaluate the normal kidney volume in young Korean men by using multi-detector computed tomography (MDCT).

MATERIALS AND METHODS

We retrospectively reviewed MDCT data of young Korean men (113 patients). After data processing, we measured the volume and length of the kidneys. Body parameters (height, body weight, body-surface area, and total body water) and laboratory data were collected. Glomerular filtration rate (GFR) was calculated using Cockcroft-Gault (CG) equation.

RESULTS

The mean kidney volume was 205.29 +/- 36.81 cm(3); and mean kidney length was 10.80 +/- 0.69 cm. The former correlated significantly with height, body weight, body-surface area, and total body water (p < 0.05, correlation coefficient : gamma = 0.328, 0.649, 0.640, and 0.638, respectively). The latter also correlated significantly with all body indexes, however the correlation was weaker, except with height (p < 0.05, correlation coefficient : gamma = 0.457, 0.473, 0.505, and 0.503, respectively). Only kidney volume significantly predicted estimated GFR (adjusted R(2) = 0.431, F = 85.90 and p < 0.05).

CONCLUSION

The kidney volume measured with MDCT is correlated well with body parameters, and is useful to predict renal function.

Conversion of single-crystalline C60 nanodisks and nanorods into graphitic nanostructures via hydrogen thermal annealing

We have developed a process to convert C(60) nanostructures into graphitic nanostructures. Disk-shaped and wire-shaped C(60) nanostructures synthesized by the liquid-liquid interfacial precipitation method, the vapor-solid process, and solvent evaporation were successfully converted into graphitic structures by thermal annealing in hydrogen at 900 degrees C. Scanning electron and tunneling electron microscopic studies confirmed that the converted nanostructures were composed of multi-graphitic structures such as multi-walled carbon nanotubes, carbon nanofibers, and carbon onions. Fourier transform Raman spectroscopy and conductance measurements were carried out to further confirm the successful formation of graphitic layers. In the Raman spectra, the nanostructures converted from C(60) disks showed signature D, G, and G(') bands of graphitic structures, while the A(g) mode (1469 cm(-1)) of the original C(60) molecule disappeared. C(60) nanowire devices fabricated for the conductance measurements of the converted structures showed dramatically decreased resistance (R approximately 100 kOmega) compared to the pristine C(60) wire (R>100 MOmega). Further manipulation of the reaction environment, including the gas and the annealing temperature, may reveal a new way to attain diverse graphitic nanostructures economically.

Interaction of nitric oxide and renin angiotensin system in pulmonary arterial circulation of RHR

We investigated the interaction between nitric oxide and the renin angiotensin system in regulating isolated pulmonary arterial tension and pulmonary arterial pressure (PAP) in renal hypertensive rats (RHR) made by complete ligation of left renal artery. Losartan induced a depressor response that was smaller in RHR than in normotensive rats (NR) (3.3 and 7.0 mmHg, respectively, at 3.0 mg/kg, p<0.05), and the response was significantly reduced by N(G)-nitro-L-arginine methyl ester (L-NAME). Angiotensin II elevated the PAP (7.6 and 10.8 mmHg at 0.1 mug/kg; 20.3 and 23.6 mmHg at 1.0 mug/kg, respectively) and contracted the isolated pulmonary artery (pD(2): 8.79 and 8.71, respectively) from both NR and RHR with similar magnitude, and these effects were significantly enhanced by L-NAME in NR, but not in HRR. Acetylcholine lowered the PAP slightly less effectively in RHR than in NR (3.8 and 6.0 mmHg at 10 mug/kg, respectively) and relaxed the pulmonary artery precontracted with norepinephrine in both rats with similar magnitude (E(max): 60.8 and 63.6%, respectively), and the effect being completely abolished after pretreatment with L-NAME or removal of endothelial cells. These results suggest that nitric oxide interacts with renin angiotensin system to control the pulmonary vascular tension and pulmonary arterial circulation of RHR.

Enzymatic Hydrolysis of Heated Whey: Iron-Binding Ability of Peptides and Antigenic Protein Fractions

This study evaluated the influence of various enzymes on the hydrolysis of whey protein concentrate (WPC) to reduce its antigenic fractions and to quantify the peptides having iron-binding ability in its hydrolysates. Heated (for 10 min at 100 degrees C) WPC (2% protein solution) was incubated with 2% each of Alcalase, Flavourzyme, papain, and trypsin for 30, 60, 90, 120, 150, 180, and 240 min at 50 degrees C. The highest hydrolysis of WPC was observed after 240 min of incubation with Alcalase (12.4%), followed by Flavourzyme (12.0%), trypsin (10.4%), and papain (8.53%). The nonprotein nitrogen contents of WPC hydrolysate followed the hydrolytic pattern of whey. The major antigenic fractions (beta-lactoglobulin) in WPC were degraded within 60 min of its incubation with Alcalase, Flavourzyme, or papain. Chromatograms of enzymatic hydrolysates of heated WPC also indicated complete degradation of beta-lactoglobulin, alpha-lactalbumin, and BSA. The highest iron solubility was noticed in hydrolysates derived with Alcalase (95%), followed by those produced with trypsin (90%), papain (87%), and Flavourzyme (81%). Eluted fraction 1 (F-1) and fraction 2 (F-2) were the respective peaks for the 0.25 and 0.5 M NaCl chromatographic step gradient for analysis of hydrolysates. Iron-binding ability was noticeably higher in F-1 than in F-2 of all hydrolysates of WPC. The highest iron contents in F-1 were observed in WPC hydrolysates derived with Alcalase (0.2 mg/kg), followed by hydrolysates derived with Flavourzyme (0.14 mg/kg), trypsin (0.14 mg/kg), and papain (0.08 mg/kg). Iron concentrations in the F-2 fraction of all enzymatic hydrolysates of WPC were low and ranged from 0.03 to 0.05 mg/kg. Fraction 1 may describe a new class of iron chelates based on the reaction of FeSO4 x 7 H2O with a mixture of peptides obtained by the enzymatic hydrolysis of WPC. The chromatogram of Alcalase F-1 indicated numerous small peaks of shorter wavelengths, which probably indicated a variety of new peptides with greater ability to bind with iron. Alcalase F-1 had higher Ala (18.38%), Lys (17.97%), and Phe (16.58%) concentrations, whereas the presence of Pro, Gly, and Tyr was not detected. Alcalase was more effective than other enzymes at producing a hydrolysate for the separation of iron-binding peptides derived from WPC.

Taste and odour issues in South Korea's drinking water industry

This paper reviews taste and odour (T&O) issues of South Korea's water industry. For this purpose, an overview of the water supply systems and drinking water standards is presented and some results from citizen surveys for customer satisfaction are included. A case study is presented in which the water intake was shifted from inside a main reservoir to a downstream location due to T&O problems. It is true that the South Korean water industry has long relied on the tolerance of consumers for periodic T&O events. Recently the South Korean water industry has become aware that the T&O problems are at the centre of consumers' concerns and has taken several positive approaches. These include monitoring T&O events using sensory and instrumental methods, installation of a baffled-channel PAC contactor and application of advanced water treatment processes.

Effect of condensate of food waste (CFW) on nutrient removal and behaviours of intercellular materials in a vertical submerged membrane bioreactor (VSMBR)

The main objective of this study was to investigate the effect of condensate of food waste (CFW) on nutrient removal in a pilot-scale vertical submerged membrane bioreactor (VSMBR) treating municipal wastewater having total-chemical oxygen demand to total-nitrogen ratio (T-COD/T-N) of 5.5. In this reactor, the average removal efficiencies of T-COD, T-N, and T-P (total-phosphorus) were 96%, 74%, and 78%, respectively at 8-h hydraulic retention time (HRT), 60-day sludge retention time (SRT), and internal recycle rate of 400%. As the CFW was supplemented with 0.86% of the influent flow rate, the T-N and T-P removal efficiencies increased to 81% and 91%, respectively. Accordingly, in batch tests, it was concluded that the supply of CFW improved enhanced biological phosphorus removal (EBPR) activity of microorganisms resulting in improvement of nutrient removal efficiency. Under this condition, several kinds of poly-hydroxyalkanoates (PHAs) were detected inside the cells.

Development of an innovative vertical submerged membrane bioreactor (VSMBR) for simultaneous removal of organic matter and nutrients

A novel vertical submerged membrane bioreactor (VSMBR) composed of anoxic and oxic zones in one reactor was developed in an attempt to reduce the problems concerning effective removal of pollutants from synthetic wastewater including glucose as a sole carbon source as well as membrane fouling. The optimal volume ratio of anoxic zone/oxic zone was found as 0.6. The desirable internal recycle rate and hydraulic retention time (HRT) for effective nutrient removal were 400% and 8h, respectively. Under these conditions, the average removal efficiencies of total nitrogen (T-N) and total phosphorus (T-P) were 75% and 71%, respectively, at the total chemical oxygen demand (T-COD)/T-N ratio of 10. In addition, the VSMBR showed high specific removal rates of nitrogen and phosphorus while the biomass growth yield from the reactor was about 20% of the conventional activated sludge process.

Simultaneous treatment of sewage sludge and food waste by the unified high-rate anaerobic digestion system

This study aimed to evaluate the performance of the unified high-rate anaerobic digestion (UHAD) system treating co-substrate of sewage sludge and food waste. A 24-hr operating sequence consisted of four steps including fill, react, settle, and draw. The effects of co-substrate and organic loading rate (OLR) on the performance were investigated to verify the system applicability. In each OLR, the UHAD system showed higher CH4 recovery (> 70%), CH4 yield (0.3 L CH4/g VSadded) and CH4 production rate (0.6 L CH4/L/d) than the control system. In the specific methanogenic activity (SMA) tests on thermophilic biomass of the UHAD system, the average SMA of acetate (102 mL CH4/gVSS/d) was much higher than those of butyrate (85 mL CH4/g SS/d) and propionate (42 mL CH4/gVSS/d). It was demonstrated that the UHAD system for co-digestion resulted in higher methane yield and methane production rate due to sequencing batch operation, thermophilic digestion, and co-digestion. The enhanced performance could be attributed to longer retention time of active biomass, faster hydrolysis, higher CH4 conversion rate, and balanced nutrient conditions of co-substrate in the UHAD system. Consequently, this optimized unification could be a viable option for the simultaneous treatment of two types of OFMSW with high stability.