Black Yeasts-Like Fungi Isolated from Dialysis Water in Hemodialysis Units

Hemodialysis in patients with chronic renal failure promotes the removal of toxic substances, water, and minerals from the body and often takes place in specialized clinics. Microbial contamination of dialysis fluid is a serious problem in therapy. One of the sources of contamination is the water used to prepare the dialysate. In Brazil, legislation regulating the microbiological quality of water for dialysis does not cover waterborne microbes such as Pseudomonas, mycobacteria, and fungi. The aim of the present study was to quantify, isolate, and identify fungi present in water systems in six hemodialysis units in Curitiba, Paraná state, Brazil. Fungi were analyzed by surface plating and membrane filtration. Isolates were identified by morphology, while the dematiaceous fungi were identified by sequencing the rDNA ITS region. It was found that 66 % of the samples presented fungi, while black fungi were present in 46 % of all samples. Twenty-eight isolates from treated water for dialysis and dialysate were identified by sequencing and were found to be Exophiala pisciphila, E. cancerae, E. equina, and Rhinocladiella similis. The presence of dematiaceous fungi may pose a risk for debilitated hospitalized patients.     

Pyrexial Reactions during Haemodialysis

The characteristics, circumstances, and treatment of 450 pyrexial reactions occurring in 468 patient-months over a period of two and a half years, using a warm single-pass Kiil system, were studied. There is a wide variation in severity of symptoms and morbidity. The incidence of pyrexial reactions has an epidemic pattern within the hospital unit. Patients on dialysis at home have reactions much less often than patients in hospital.Blood cultures taken from patients during each of the 450 reactions showed a growth on 38 occasions, but this was not significantly different from the incidence of positive cultures taken simultaneously from control patients during haemodialysis. Reactions were not correlated with bacterial growth from the blood compartment of the kidney before dialysis. There was no difference in incidence of reactions when using different types of equipment which were either a central tank distribution system with bedside monitors or chemically- or heat-sterilized individual proportioning pump systems. Reactions were also noted with the disposable coil kidney and recirculating single-pass (R.S.P.) system, but presented different features from those of the Kiil kidney.The incidence of reactions was not related to the albuminoid nitrogen content of the water supply. Reactions were not abolished by deionization of the tap-water.     

Intermittent Hemodialysis in Terminal Chronic Renal Failure

Seven patients with chronic renal failure underwent intermittent hemodialysis for five to 37 months (111 patient-months on a twice-weekly basis) employing arteriovenous Teflon-Silastic cannulas and the modified two-layer Kiil hemodialyzer. A single-pass 37° C. dialysate system has been used. One patient died of an indirectly related cause. All other patients have been successfully rehabilitated and now carry on normal activity of moderate sedentary type. Complications included recurring infection and clotting of arteriovenous cannulas. Hypertension and anemia were common complications requiring careful control. Peripheral neuropathy was noted in five of the seven patients but was of clinical significance in only one patient. Metastatic calcification, osteoporosis and urolithiasis also occurred in this patient. Peptic ulcers with hemorrhage developed in two patients. The degree of rehabilitation and psychological adjustment achieved by this group of patients strongly indicates the need for expansion of dialysis facilities and further research into the medical and economic aspects of dialysis.     

Selenium,Lead, and Cadmium Levels in Renal Failure Patients in China

Whole blood and serum samples of Chinese stable chronic renal failure (CRF) patients (n = 81), hemodialysis patients (n = 135), posttransplant patients (n = 60), and subjects with normal renal function (NRF; N = 42) were collected, as well as water and dialysate samples from five dialysis centers. The concentration of selenium (Se), lead (Pb), and cadmium (Cd) was measured by atomic absorption spectrometry. The mean serum Se levels in patients with different degrees of renal failure were significantly lower than those of subjects with NRF (p < 0.01). Pb levels were not increased in renal failure patients, while the Cd levels in patients with various degrees of renal failure were higher than in subjects with NRF (p < 0.05). After correcting the results of Pb and Cd for hematocrit (Hct) however, Pb levels of dialysis patients were also increased. In the dialysis population under study, blood Pb and Cd levels were closely related to the time on dialysis, while contamination of the final dialysate may also contribute to the increased blood Cd and to a less extent Pb levels. Correction for Hct may be recommended to accurately compare blood Pb and Cd levels in dialysis patients and CRF patients with varying degrees of anemia to those of subjects with NRF.     

Prevalence of nontuberculous mycobacteria in water supplies of hemodialysis centers

Infection of hemodialysis patients with nontuberculous mycobacteria (NTM) has been associated with water used in reprocessing hemodialyzers. This study was conducted to determine the prevalence of NTM and other bacteria in water samples collected over a 13-week period from 115 randomly selected dialysis centers in the United States. Total viable counts were determined by membrane filter assays; increased recovery of NTM was obtained by dosing a portion of each water sample with 1% formaldehyde (HCHO) before filtering. NTM were widely distributed and occurred with a high frequency in water supplies in dialysis centers. NTM were detected in water from 95 centers (83%), and 50% of all samples examined contained NTM. The results of this study support recommendations to use 4% HCHO or a chemical germicidal equivalent for disinfecting dialyzers that are to be reused.     

Prevalence of nontuberculous mycobacteria in water supplies of hemodialysis centers.

Infection of hemodialysis patients with nontuberculous mycobacteria (NTM) has been associated with water used in reprocessing hemodialyzers. This study was conducted to determine the prevalence of NTM and other bacteria in water samples collected over a 13-week period from 115 randomly selected dialysis centers in the United States. Total viable counts were determined by membrane filter assays; increased recovery of NTM was obtained by dosing a portion of each water sample with 1% formaldehyde (HCHO) before filtering. NTM were widely distributed and occurred with a high frequency in water supplies in dialysis centers. NTM were detected in water from 95 centers (83%), and 50% of all samples examined contained NTM. The results of this study support recommendations to use 4% HCHO or a chemical germicidal equivalent for disinfecting dialyzers that are to be reused.     

Liver failure: basis of benefit of therapy with the molecular adsorbents recirculating system

Accumulation of albumin-bound toxins is known to occur in liver failure, and to variable extents is responsible for the associated end-organ dysfunctions (kidney, circulation, brain). The toxin-binding and scavenging functions of albumin are exploited in albumin dialysis for removal of these toxins. The extracorporeal liver support device known as molecular adsorbents recirculating system (MARS) is based on dialysis across an albumin-impregnated membrane, using 20% albumin as dialysate. Charcoal and anion exchange resin columns in the circuit help cleanse and regenerate the dialysate. Clinical studies over the last few years have demonstrated proven reduction in hyperbilirubinaemia, along with an improvement in encephalopathy, systemic haemodynamics and renal function in liver failure patients, as well as apparent improvement in survival. The results of larger controlled clinical trials, as well as studies investigating the pathophysiological basis of its effect, are awaited.     

平衡型氨基酸透析液对维持性血液透析患者血浆游离氨基酸含量的影响

目的:研究一种平衡型氨基酸透析液,探讨其对维持性血透患者血游离氨基酸含量的影响。方法:实验采用自身对照设计,应用蛋白水解法测定、分析应用氨基酸透析液血透前后患者血浆氨基酸含量,并同时测定应用碳酸盐透析液患者及健康人血浆游离氨基酸作为比较。结果:经碳酸盐透析后,患者血浆大多数游离氨基酸和总氨基酸含量显著降低。给予平衡氨基酸透析液能不同程度改善患者血浆游离氨基酸的含量。结论:平衡型氨基酸透析液能减少血中部分氨基酸的丢失。     

Hollow fiber countercurrent dialysis for continuous buffer exchange of high-value biotherapeutics

Buffer exchange, desalting, and formulation of high-value biotherapeutics are currently performed using batch diafiltration (DF); however, this type of tangential flow filtration process may be difficult to implement as part of a fully continuous biomanufacturing process. The objective of this study was to explore the potential of using countercurrent dialysis for continuous protein formulation and buffer exchange. Experiments were performed using concentrated solutions of immunoglobuin G (IgG) with commercially available hollow fiber dialyzers having 1.5 and 1.8 m² membrane surface area. More than 99.9% buffer exchange was obtained over a range of conditions, as determined from the removal of a model impurity (vitamin B₁₂). The dialyzers were able to process more than 0.5 kg of IgG per day in an easily scalable low-cost process. In addition, buffer requirements were less than 0.02 L of buffer per gram IgG, which is several times less than that used in current batch DF processes. These results clearly demonstrate the potential of using low-cost hollow fiber dialyzers for buffer exchange and product formulation in continuous bioprocessing. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2763, 2019.     

Exchangeable Potassium Study in Patients Undergoing Chronic Haemodialysis

Seven patients with chronic renal failure treated with haemodialysis for 4 to 24 months were found to have low exchangeable potassium levels. Before dialysis the plasma potassium was normal or somewhat raised (possibly owing to acidosis), though the exchangeable potassium was low. Acidosis was corrected during dialysis; plasma potassium levels fell, but clinical and electrocardiographic changes of hypokalaemia were absent. The level of 1 mEq/litre in the dialysate fluid may be too low for use in prolonged haemodialysis.     

Dialysate dihydroxyphenylglycol as a window for in situ axoplasmic norepinephrine disposition

To examine basal axoplasmic norepinephrine (NE) kinetics at the in situ cardiac sympathetic nerve ending, we applied a dialysis technique to the heart of anesthetized cats and performed the dialysate sampling with local administration of a pharmacological tool through a dialysis probe. The dialysis probe was implanted in the left ventricular wall, and dihydroxyphenylglycol (DHPG, an index of axoplasmic NE) levels were measured by liquid chromatogram-electrochemical detection. Control dialysate DHPG levels were 161+/-19 pg/ml. Pargyline (monoamine oxidase inhibitor, 1 mM) decreased the dialysate DHPG levels to 38+/-10 pg/ml. Further alpha-methyl-para-tyrosine, omega-conotoxin GVIA, desipramine (NE synthesis, release and uptake blockers) decreased the dialysate DHPG levels to 64+/-19, 106+/-15, 110+/-22 pg/ml, respectively. In contrast, reserpine (vesicle NE transport inhibitor, 10 microM) increased the dialysate DHPG levels to 690+/-42 pg/ml. Thus, NE synthesis, metabolism and recycling (release, uptake and vesicle transport) affected basal intraneuronal NE disposition at the nerve endings. Measurement of DHPG levels through a dialysis probe provides information about basal intraneuronal NE disposition at the cardiac sympathetic nerve endings. Yohimbine (alpha(2)-adrenoreceptor blocker, 10 microM) and U-521 (catechol-O-methyltransferase blocker, 100 microM) did not alter the dialysate DHPG levels. Furthermore, there were no significant differences in the reserpine induced DHPG increment between the presence and absence of desipramine (10 microM) or alpha-methyl-para-tyrosine (100 mg/kg i.p.). These results may be explained by the presence of two axoplasmic pools of NE, filled by NE taken up and synthesized, and by NE overflow from vesicle. The latter pool of NE may be closed to the monoamine oxidase system in the axoplasma.     

Contamination of pear concentrate by Alicyclobacillus from recirculating flume water during fruit concentrate production

Alicyclobacillus and viable aerobic counts were monitored at nine different production stages of pear concentrate, with the functioning of either a recirculating or a one-pass flume water system. Significantly (P < 0.05) higher levels of Alicyclobacillus were detected in the final pasteurized product (102–104°C for 90 s) when the recirculating flume water system was operational. An average of 1.19 Log₁₀ c.f.u. ml⁻¹ vegetative cells and 1.35 Log₁₀ c.f.u. ml⁻¹ endospores were recovered, whereas 0 c.f.u. ml⁻¹ vegetative cells and endospores were detected when the one-pass flume water system was operational. Alicyclobacillus levels did not differ significantly (P > 0.05) in condensate water during the functioning of the two flume water systems, with 1.81 Log₁₀ c.f.u. ml⁻¹ vegetative cells and 1.01 Log₁₀ c.f.u. ml⁻¹ endospores (recirculating system) and 0.78 Log₁₀ c.f.u. ml⁻¹ vegetative cells and 0.42 Log₁₀ c.f.u. ml⁻¹ endospores (one-pass system) recovered, respectively. As a result, water treatment protocols should be established if untreated recirculating flume or condensate water is to be used in order to prevent Alicyclobacillus contamination and accumulation in the processing environment.     

Glycosylated Hemoglobin and Albumin-Corrected Fructosamine Are Good Indicators for Glycemic Control in Peritoneal Dialysis Patients

Purpose

Diabetes mellitus (DM) is the most common cause of end-stage renal disease and is an important risk factor for morbidity and mortality after dialysis. However, glycemic control among such patients is difficult to assess. The present study examined glycemic control parameters and observed glucose variation after refilling different kinds of fresh dialysate in peritoneal dialysis (PD) patients.

Methods

A total of 25 DM PD patients were recruited, and continuous glucose monitoring system (CGMS) was applied to measure interstitial fluid (ISF) glucose levels at 5-min intervals for 3 days. Patients filled out diet and PD fluid exchange diaries. The records measured with CGMS were analyzed and correlated with other glycemic control parameters such as fructosamine, albumin-corrected fructosamine (AlbF), glycosylated hemoglobin (HbA1c), and glycated albumin levels.

Results

There were significant correlations between mean ISF glucose and fructosamine (r = 0.45, P<0.05), AlbF (r = 0.54, P<0.01), and HbA1c (r = 0.51, P<0.01). The ISF glucose levels in glucose-containing dialysate increased from approximately 7–8 mg/dL within 1 hour of exchange in contrast to icodextrin dialysate which kept ISF glucose levels unchanged.

Conclusion

HbA1c and AlbF significantly correlated with the mean ISF glucose levels, indicating that they are reliable indices of glycemic control in DM PD patients. Icodextrin dialysate seems to have a favorable glycemic control effect when compared to the other glucose-containing dialysates.     

An experimental, non-uremic rabbit model of peritoneal dialysis

Peritoneal dialysis (PD) is a well established method of depuration in uremic patients. Standard dialysis solutions currently in use are not biocompatible with the peritoneal membrane. Studying effects of dialysate on peritoneal membrane in humans is still a challenge. There is no consensus on the ideal experimental model so far. We, therefore, wanted to develop a new experimental non-uremic rabbit model of peritoneal dialysis, which would be practical, easy to conduct, not too costly, and convenient to investigate the long-term effect of dialysis fluids. The study was done on 17 healthy Chinchilla male and female rabbits, anesthetized with Thiopental in a dose of 0.5 mg/kg body mass. A catheter, specially made from Tro-soluset (Troge Medical GMBH, Hamburg, Germany) infusion system, was then surgically inserted and tunneled from animals' abdomen to their neck. The planned experimental procedure was 4 weeks of peritoneal dialysate instillation. The presented non-uremic rabbit model of peritoneal dialysis is relatively inexpensive, does not require sophisticated technology and was well tolerated by the animals. Complications such as peritonitis, dialysis fluid leakage, constipation and catheter obstruction were negligible. This model is reproducible and can be used to analyze the effects of different dialysis solutions on the rabbit peritoneal membrane.     

Scope and limitations of in vivo brain dialysis: a comparison of its application to various neurotransmitter systems

Brain dialysis is rapidly becoming a routine research method with a wide range of applications. Since 1982 this sampling technique is frequently used as a method to study the in vivo release of endogenous neurotransmitters such as dopamine, noradrenaline, serotonin, acetylcholine and certain amino acids. In this review most of the studies that have appeared in this field, are evaluated. Special attention was given to the question whether the neurotransmitter content in the dialysate is related to neurotransmission. Criteria such as the presence of a high tissue/dialysate concentration ratio, the sensitivity of the transmitters to membrane active compounds and the occurrence of receptor-mediated effects, are discussed. It is concluded that dopamine, noradrenaline and acetylcholine found in the dialysate are directly derived from neurotransmission, whereas the overflow of excitatory amino acid neurotransmitters is related to neurogenic as well as to metabolic events.     

Serotonin-mediated increases in the extracellular levels of beta-endorphin in the arcuate nucleus and nucleus accumbens: a microdialysis study

Although the involvement of both endogenous opioid and serotonergic systems in modulation of pain and emotion was suggested, the neurochemical interaction between these systems in the brain has not previously been studied directly. Herein, the effects of the local application of serotonin (5-HT) and fluoxetine (a 5-HT reuptake inhibitor) on extracellular levels of beta-endorphin in the arcuate nucleus and nucleus accumbens were assessed in freely moving rats using in vivo microdialysis. The mean basal concentrations of beta-endorphin in dialysates obtained from the arcuate nucleus and nucleus accumbens were 259.9 and 143.3 pM, respectively. Specific lesion of the serotonergic system by 5,7-dihydroxytryptamine (5,7-DHT) caused a significant decrease in these dialysate beta-endorphin levels. When 5-HT (0.25-5 microM) was added to the perfusion solution, the levels of beta-endorphin in the dialysate from the arcuate nucleus increased (186-296% of baseline), in a concentration-dependent manner. In the nucleus accumbens, 0.5 and 2 microM 5-HT in the perfusion fluid did not affect the levels of beta-endorphin in the dialysate, whereas 5 and 10 microM 5-HT caused an increase of approximately 190% of baseline. When fluoxetine (250 microM) was present in the perfusing solution, the levels of beta-endorphin in the dialysates from the arcuate nucleus and nucleus accumbens increased two- to threefold. This effect was not obtained in the 5,7-DHT-lesioned rats. Thus, 5-HT, either endogenously or exogenously delivered, appears to facilitate the release of beta-endorphin in the arcuate nucleus and nucleus accumbens. This indication of an interaction between serotonergic and endorphinic systems may be relevant for assessing pain and mood disorder circuits and the mode of action of antidepressant drugs.     

Detection of Trp-P-1 and Trp-P-2, carcinogenic tryptophan pyrolysis products, in dialysis fluid of patients with uremia

In order to estimate the exposure levels of mutagenic and carcinogenic heterocyclic amines in humans, we developed a high-performance liquid chromatography method to detect 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) in dialysis fluid of patients with uremia. Using this methods, dialysis fluid of 12 patients who had received hemodialysis treatment or continuous ambulatory peritoneal dialysis was examined. Trp-P-1 was detected in dialysate of all uremic patients (727 +/- 282 pmoles, n = 12). In patients who had been treated with continuous ambulatory peritoneal dialysis, the average amount of Trp-P-1 found in whole dialysate (6 l) per day was 710 +/- 203 pmoles (mean +/- S.D., n = 8). Moreover, Trp-P-2 could be detected in 5 out of 12 patients (206 +/- 85 pmoles, n = 5). These results indicate that patients with uremia are actually exposed to carcinogenic tryptophan pyrolysis products. The average exposure level of Trp-P-1 in uremic patients apparently exceeded 710 pmoles (150 ng) per day.     

Peritoneal dialysis in infants.

A commercially available closed dialysis system and a new peritoneal cannula with potential advantages for infants have been developed. The dialysis set includes three dialysate bags that may be connected to the filling burette; the warming coil of the set is placed in a thermostatically controlled water bath. The peritoneal catheter comprises a flexible tube with side holes and a sharp short bevelled needle with obturator. Advantages of the new equipment over previously available equipment are that the cannula is easier to insert; there is less risk of contaminating the dialysate since the tubing set is unbroken from supply to cannula; the mix of the dialysate may be changed easily without interrupting dialysis; and the equipment may be assembled easily by unskilled staff.     

Orphanin FQ/Nociceptin Modulation of Mesolimbic Dopamine Transmission Determined by Microdialysis

Orphanin FQ has been reported to suppress extracellular dopamine levels in the nucleus accumbens after intracerebroventricular administration. This study sought to provide evidence for an intra-ventral tegmental site of action for this effect using a dual-probe microdialysis experimental design. Orphanin FQ was applied to the ventral tegmental area of anesthetized rats by reverse dialysis while extracellular dopamine was sampled with a second dialysis probe in the nucleus accumbens. Orphanin FQ at a probe concentration of 1 mM (but not at 0.1 mM) significantly reduced nucleus accumbens dialysate dopamine levels. The receptor-inactive analogue, des-Phe1-orphanin FQ (1 mM), produced a small but significant increase in nucleus accumbens dialysate dopamine levels. Simultaneous measurement of ventral tegmental area dialysate amino acid content revealed significant increases in both GABA and glutamate during infusion of orphanin FQ (1 mM). To determine if increased GABA overflow mediates the action of orphanin FQ on mesolimbic neurons, orphanin FQ (10 nmol) was microinjected directly into the ventral tegmental area in the presence or absence of the GABA(A) receptor antagonist, bicuculline (1 nmol). Bicuculline transiently blocked the suppressive action of orphanin FQ on accumbens dialysate dopamine levels. These data indicate that orphanin FQ decreases dopamine transmission in the nucleus accumbens by inhibiting dopamine neuronal activity in the ventral tegmental area through a mechanism that may involve an increased overflow of GABA.     

Bacterial colonization and endotoxin content of a new renal dialysis water system composed of acrylonitrile butadiene styrene.

We measured endotoxin and bacterial levels in tap water, in water purified by reverse osmosis, and in dialysate samples over a 4-month period in a new 10-bed renal dialysis unit. Water treated by reverse osmosis is conducted to the 10 stations through 111 m of piping composed of acrylonitrile butadiene styrene (ABS). All determinations were made prior to the opening of the unit and after the system was purged for 35 h with all bedside station taps open. Formaldehyde disinfection of the piping system was attempted with a recommended protocol after 11 weeks by feeding 2.5 liters of 37% formaldehyde (0.85%, vol/vol) into the delivery system. Prior to water purging, 24 ng of endotoxin per ml was detected. This level decreased to 2.0 ng of endotoxin after the purging. Levels of endotoxin remained below 1.0 ng of endotoxin per ml throughout the duration of the study. In contrast, the level of viable microorganisms recovered from the treated water was approximately 3.5 X 10(4) CFU/100 ml. Even after disinfection of the system, there was no significant decrease in culturable bacteria from the water even though endotoxin levels were lower. Species isolated from the renal dialysis system were predominately pseudomonads, whereas species isolated from the tap water were Bacillus and Flavobacterium species. ABS provides a surface suitable for long-term colonization and growth of bacteria. Currently recommended decontamination protocols are ineffective in removing potentially pathogenic bacteria from ABS pipes and thus constitute an increased risk to patients undergoing dialysis.