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At least 811 records · Page 45Linked to original sources
PubMed1992

A new central supply system as alternative source for bicarbonate dialysate.

Bicarbonate dialysis is mandatory for high efficiency treatment. In most cases bicarbonate is delivered either as prepacked powder or as a stable liquid concentrate in 6-10 I plastic containers. With a newly designed central supply system (CSS) using 800 I tanks of custom-made sterile and pyrogen free concentrates, we investigated the risk of bacterial contamination of dialysate in a 30-bed dialysis unit. During three months, samples of reverse osmosis (RO) water, concentrates and dialysate were taken every two weeks. Colony forming units (CFU) were counted after 48 h incubation. Further samples were taken during nine months of continuous use of the CSS without further intermittent disinfection. None of the samples had greater than 10/ml CFU. Pseudomonas, corynebacteria and enterobacter were the predominant species. In summary, this CSS proved reliable in providing bacteriologically safe bicarbonate dialysate as defined by international standards (CFU less than 200/ml). It significantly reduces costs, workload and environmental pollution by plastic waste.

Bacteria↗
PubMed2005

[Biological effects of rare earth elements and their action mechanisms].

This paper reviewed the effects of rare earth elements on plant root development, biomass, quality, and resistance against stress. Applying appropriate amount of rare earth elements could not only promote seed germination and root development, increase plant biomass, but also improve harvest quality and plant resistance against stress. The plant uptake characteristics of rare earth elements, as well as their contents, distribution, existing forms, and cytolocalization in plants were discussed, with the focus on the effects of rare earth elements on photosynthesis and chlorophyll formation, nutrient uptake, relationships between rare earth elements and calcium, and action mechanisms of rare earth elements on cell membrane and enzymes. Rare earth elements could enhance chlorophyll content and improve photosynthetic rate, and thus, could increase plant biomass. When an appropriate amount of rare earth elements was applied, the uptake of nutrients by plant and their transformation and utilization were promoted. Rare earth elements could replace calcium ion to participate in enzymatic reactions, maintain the osmosis and stability of cell membrane, promote the protection function of cell membrane, and enhance the plant resistance capability against stress. In the end, further researches on rare earth elements were suggested.

Biomass↗
PubMed2006

Astroglial swelling for removed rat brain enlargement incubated in deoxygenated mock cerebrospinal fluid.

The source and target of edema fluid for ischemic brain swelling clinically often observed in "malignant infarction" was examined in ex vivo. Wister rat brain hemispheres were removed and incubated air-tightly in a deoxygenated artificial cerebrospinal fluid at 37 degrees for 30 min. Ionic movement into the brain tissue was calculated from their concentration changes in the incubation fluid. We found a weight increase by 11.3+/-2.5% (p<0.01) and a decrease in Na+ from 148.0 to 139.0 +/- 8.2 mEq/l (p<0.01) and an increase in K+ from 4.3 to 11.2 +/- 1.2 mEq/l. Video tape recording revealed that the brain swelling started immediately upon the incubation, and the electronmicroscopical investigation of the swollen cortical tissue revealed that the fluid moved mainly into astroglial cells. The astroglial swelling was quite similar to that of specimen taken from clinical cases at autopsy. The driving force of the water shift can be explained by discharge of thermodynamic potential, i.e., a coupled transport of water with Na+ across the cell membrane (anomalous osmosis). The swelling was not affected by addition of aquaporin blocker, mercuric chloride. It is concluded that cerebrospinal fluid bathing the brain in situ can be the source of edema fluid for ischemic brain swelling.

Animals↗
PubMed2006

CLS meets the aquaporin family: clinical cases involving aquaporin systems.

Virtually all human cells incorporate aquaporins, or water channel proteins, into their cell membrane. Indeed, many cells produce several aquaporins, each adapted for a specific physiologic function. Thus, it is not surprising that aquaporin malfunctions are associated with numerous important clinical conditions. This article describes the clinical aspects of malfunctions in aquaporins or their regulation. Although water can diffuse across biological membranes (osmosis) without the aid of a transport system, researchers had predicted for decades that rapid reabsorption by renal tubule cells must be aided by a channel or pore. Yet, not until the 1990s were the first members of the aquaporin (AQP) family identified. Led by Dr. Peter Agre, recipient of the 2003 Nobel Prize in Chemistry, researchers have since amassed an astounding amount of information about AQPs and their function. For example, the flow rate of water through AQP1 is an extraordinary three billion water molecules per second per aquaporin channel, while a relative trickle of water crosses the hydrophobic lipid bilayer of cell membranes devoid of AQPs. Our understanding of renal physiology and pathophysiology has advanced greatly as we account for the subtle implications of various AQP systems. For example, nephrogenic diabetes insipidus (NDI), the inability to produce concentrated urine, can result from several different malfunctions in the hormonally controlled AQP2 system. The list of diseases known to involve AQPs now includes: early onset of cataracts, Sjogren's syndrome, cerebral and pulmonary edemas, cirrhotic liver development of ascites, and congestive heart failure (CHF).

Aquaporin 2↗
PubMed2005

The new approaches to preservation of graft cell integrity in preservation for transplantation.

Restoration of cell plasma membrane integrity after injury is essential for the survival of animal cells. In case of graft preservation or during chemotherapy in cancer, cell membrane integrity and the process of its repair are disrupted. Cytoprotective substances are important in such cases, as well as in other diseases, for example in myocardial infarction, acute insults and in chronic neurodegenerative diseases. Hyperosmolarity is a condition in which cell membrane stability may be damaged in vivo but preserved in the in vitro conditions. Hypertonicity causes water leaving from cells by osmosis, decreasing cell volume and increasing of intracellular ionic strength. High intracellular ionic strength perturbs cellular function by decreasing the rates of biochemical reaction. We review the new experimentally studied cytoprotective substances and their application in cell membrane protection. Moreover, we present our data on the effects of hyperosmolarity and its protective effect on cell internal structure.

Animals↗
PubMed1977

Home peritoneal dialysis: 3 years' experience in Toronto.

From November 1972 to November 1975, 52 males and 39 females aged 11 to 71 years were trained for home peritoneal dialysis. Dialysis was performed through a permanent catheter 4 nights a week. The first 11 patients used the manual system, exchanging 2 / of dialysate solution every 50 to 60 minutes. Subsequently 73 patients used the automatic cycler and commercially available dialysate and 7 patients used Tenckhoff's reverse osmosis peritoneal dialysis machine. The average duration of training was 15, 11.6 and 15 dialysis days, respectively, for the three methods. For the 83 patients followed up, the average duration of home dialysis was 8.3 months (range, 0.5 to 33 months); the total number of dialyses at home was 10 571. Ten received a transplant, 20 were transferred to hospital peritoneal dialysis or hemodialysis, 8 died and 48 continued with home dialysis. Twenty-three patients had a total of 33 episodes of peritonitis, an incidence of 27.7% among the patients in the program for up to 3 years or 0.3% among all the dialyses. By November 1975, 46 patients had returned to their predialysis lifestyle, 18 were working part-time, 10 were able to work but were not doing so, and 9 were unable to work or care for themselves.

Adolescent↗
PubMedDate not supplied

Mechanism and control of fluid secretion.

Fluid secretion and reabsorption by a variety of plant and animal tissues appear to be accomplished by osmotic coupling between solute transport and water movement. The local osmosis model suggests that active accumulation of solutes within narrow folds at the cell surface may produce the local gradients that generate water flow. Both micropuncture techniques and electron-probe X-ray microanalysis have established that local osmotic gradients occur in absorptive epithelia, but they have not as yet been detected in secretory tissues.Hormonal control of secretion involves stimulation of solute pumps and adjustments of permeability to non-transported solutes. Since hormone receptors and pumps are often located on opposite surfaces of the cell, intracellular second messengers convey the secretory signal through cytoplasm. Much has been learned by study of insect tissues that are anatomically simple and that function for long periods in vitro. Aspects of hormone-receptor interaction have been explored, including the action of halluninogenic molecules. In insect salivary glands cyclic AMP appears to stimulate cation transport, while calcium increases anion permeability. The various second messengers probably interact with each other in complex feedback loops that stabilize the system and make it quickly responsive to hormone. Cyclic AMP may stimulate release of calcium from mitochondria. Unresolved is the way second messengers alter properties of the cell surface.

Animals↗
PubMedDate not supplied

[Spectrophotometric study of the physico-chemical properties of lysosomes isolated from rat liver].

Physico-chemical properties of intact lysosomes isolated from rat liver tissue were studied using spectrophotometric methods. The lysosomal suspension did not show specific maximal peaks in spectra of light passing through, scattering and absorbance. Stability of the suspension was most suitably evaluated at 520 nm. The rate of lysosomes lysis was distinctly increased at temperature above 37 degrees at pH below 3.0 and above 7.0 as well as in osmotic pressure (pi) exceeding 0.75 MPa. The temperature of phase conversion at 12.5 degrees and 38.5 degrees was calculated from Arrhenius plot. Activating energy of the lysosomes thermolysis was equal to 50, 2 and 18 kcal/mol for solid, mixed and liquid phases of lysosomal membranes, respectively. Additional incubation of the initial lysosomal suspension at 0-4 degrees within 24 hrs led to an increase in osmosis- and acid-stability within all the ranges of pi and pH values studies as well as to decrease of its sensitivity to hypothermia (10-30 degrees) but not to hyperthermia (above 37 degrees). Cadaverine at final concentration 1.0 and 0.1 mM protected lysosomes from thermolysis. Osmotic-resistance, acid-stability and thermotolerance may be used as available dynamic parameters of the particles structure state as well as in evaluation of deteriorating effects of various physicochemical factors in vivo and in vitro.

Animals↗
PubMed1990

[Retinal degeneration after intravitreal injection of ornithine. 1. Early change after administration].

Retinal damage 1 to 7 days after intravitreal injection of 1-ornithine hydrochloride solution into monkey eyes was investigated. Clinically the retinal pigment epithelium (RPE) showed edema, and hyperfluorescence on fluoroangiograms, predominantly in the equatorial region at 3 to 7 days. No retinal changes were seen at the posterior pole. Histopathologically, RPE in the equatorial region showed severe damage 24 hours after injection, becoming liquefactively necrotic and degenerated at 3 to 7 days. Early changes in RPE consisted of an increase in the number of secondary lysosomes, disappearance of basal infolding, destruction of most of the smooth endoplasmic reticulum, shortening of microvilli, and marked swelling of mitochondria. These RPE changes were seen slightly in the posterior pole. There were slight changes in the inner retina including photoreceptors. In eyes injected intravitreally by hi-osmosis of 3.5% NaCl solution, with equivalent osmolarity to ornithine solution, mild changes of microvilli and mitochondria were seen, but not necrotic changes. Our experiment showed that intravitreal injection of a small amount of 1-ornithine hydrochloride induced severe RPE damage. Selective toxicity of ornithine to RPE appeared mainly in the equatorial region.

Animals↗
PubMed1990

Newcastle bone disease in Hong Kong: a study of aluminum associated osteomalacia.

We measured serum aluminum concentrations in 104 haemodialysis patients from 3 centres in Hong Kong. We found that the 52 patients dialyzed in unit A had much higher mean aluminium levels (100 micrograms/L) than those from the other two units (61 and 39 micrograms/L respectively). In unit A, where water treatment by reverse osmosis had been introduced only recently, 30.8% of patients had fractures/looser zones, 46.2% had rugger-jersey spine and 28.8% had skeletal erosions. When these patients were divided into two groups according to whether their serum aluminium concentration was below or above 100 micrograms/l, the latter patients had significantly lower alkaline phosphatase, serum phosphate, and higher total prescribed dose of aluminium hydroxide. It was concluded that both dialysate aluminium and oral aluminium intake seemed to have contributed to the high incidence of osteomalacic fractures among Unit A patients. In eight of these patients serum aluminium increased by more than 150 micrograms/L after four weeks of receiving 1.5 g desferrioxamine twice weekly. Serial X-rays showed that the mean time after dialysis for the appearance of fractures/Looser zones was 72 months. Three patients developed fractures/Looser zones after successful renal transplantation; and it was postulated that the prompt excretion of aluminium permitted increased osteoclastic activity, resulting in fractures in these patients.

Adult↗
PubMed1990

[Extrarenal elimination procedures in acute kidney failure].

In spite of continuous progress in intensive care during the past two decades, there is no definite proof that the prognosis of critically ill patients with acute renal failure has actually improved. Nevertheless, the development of hemofiltration and hemodiafiltration and of the continuous methods has extended the therapeutic spectrum and allows therapy to be adapted to the specific cardiovascular and metabolic situation of the individual patient. Detoxification is carried out intracorporeally in peritoneal dialysis or extracorporeally by means of filters and membranes with different filtration properties. Peritoneal dialysis is seldom indicated in operative patients, because of its low efficiency and the hypercatabolism that is often observed, except in situations where continuous abdominal lavage is desired, as in peritonitis or necrotizing pancreatitis. The standard detoxification method is hemodialysis in which the filter is perfused in the opposite direction to blood flow. Solute transport is the result of diffusion, osmosis and, to a minor extent, convection, and the elimination of small molecules is favored. As huge amounts of dialysate have to be used, a central water regeneration unit is the technical prerequisite for hemodialysis. In critically ill patients bicarbonate dialysis should be preferred, because it is hemodynamically better tolerated. Hemofiltration relies on convection rather than diffusion through a membrane with a cut-off between 20,000 and 50,000 daltons. The ultrafiltrate largely resembles plasma water. Fluid loss is substituted by appropriate electrolyte solutions allowing space for negative balances and hypercaloric parenteral nutrition. Hemofiltration is better tolerated than hemodialysis and was introduced to improve the elimination of toxic middle molecules. In intensive care units without access to hemodialysis or intermittent hemofiltration continuous arteriovenous hemofiltration (CAVH), first proposed by P. Kramer, has become an alternative, mainly because of its simplicity and the absence of hemodynamic side effects. The drawback of this method is its limited efficiency. In hypercatabolic patients daily ultrafiltration rates of 10-15 l will not reduce blood urea sufficiently. The same holds true for severe hyperkalemia. One attempt to increase efficiency is predilution, which involves adding part of the substitution fluid before the filter, to enhance blood flow and to increase the effective filtration pressure by lowering the oncotic pressure of the plasma. Predilution will increase the net urea clearance by some 20%. Another way to enhance filtration is to apply negative pressure to the membrane with the aid of an infusion pump at the filtrate side. The development of better filters with smaller resistances may further increase filtration rates.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Kidney Injury↗
PubMed1990

Electrokinetic energy conversion by aqueous oxalic acid, citric acid, ascorbic acid, hippuric acid, and acetyl salicylic acid across urinary bladder membranes.

Efficiency of energy conversion for electro-osmosis and streaming potential and the degree of coupling of acids across urinary bladder membranes of goat have been computed using non-equilibrium thermodynamic theory. The energy conversion maxima and degree of coupling for acids responsible for the formation of urinary calculi are found to be much low as compared to urea and urine.

Animals↗
PubMed1986

[Changes in axonal transport induced by ischemia].

Effect of ischemia, resulted from ligation of the abdominal part of the aorta, on the rate of anterograde and retrograde transport in the nervous pathways of the posterior roots has been studied in the canine spinal nerves. The anterograde transport rate is studied after injection of labelled 14C-leucine into spinal ganglia. An increased rate from 365 mm/day to 487 mm/day is revealed. The retrograde transport rate, that is estimated by means of horseradish peroxidase injected into the spinal cord, increases after the ischemia from 141 mm/day to 200 mm/day. A suggestion is made that the increase in the rate is caused by certain changes in ionic balance and osmosis produced by ischemia.

Adenosine Triphosphate↗
PubMed1989

Can low-dosage aluminium hydroxide control the plasma phosphate without bone toxicity?

Sixteen patients treated exclusively by haemodialysis using reverse osmosis water treatment for up to 7 years (mean 49.3 +/- 17 months) were assessed for evidence of bone aluminium accumulation and toxicity. All patients were treated with aluminium hydroxide phosphate binders for the duration of dialysis but the dosage was restricted to a maximum of 2.85 g daily (mean daily dose 2.6 +/- 0.8 g). The mean plasma phosphate over the 12 months prior to the study was 1.68 +/- 0.42 mmol/l and in only three patients was adequate control of the plasma phosphate not achieved. No patient had evidence of fracturing bone disease. Bone aluminium staining was present in only two patients but was seen at the calcification front in only one of these. Three patients had histological evidence of osteomalacia, but in none was aluminium staining present. Mean bone aluminium was moderately high at 36.67 +/- 31 micrograms/g and in only three patients exceeded 40 micrograms/g. This study indicates that adequate control of the plasma phosphate can be achieved with low dosage of aluminium hydroxide, and in the medium term is not associated with evidence of bone aluminium toxicity.

Aged↗
PubMedDate not supplied

National surveillance of dialysis-associated diseases in the United States, 1987.

The Centers for Disease Control surveyed 1,630 chronic hemodialysis centers in the United States in 1987 in conjunction with the annual facility survey done by the Health Care Financing Administration. Information was obtained on the following diseases and practices: 1) hepatitis B virus (HBV) infection in patients and staff members; 2) infection control procedures for hepatitis B surface antigen (HBsAg)-positive patients; 3) frequency of HBsAg serologic screening; 4) use of hepatitis B vaccine; 5) non-A, non-B hepatitis in patients and staff members; 6) pyrogenic reactions and septicemia; 7) dialysis dementia; 8) new dialyzer syndrome; 9) high flux dialysis; 10) reuse of dialyzers, dialyzer caps, bloodlines, transducer filters; 11) cleaning and disinfection procedures; and 12) human immunodeficiency virus (HIV) infection. The response rate to a mailed questionnaire was 91%. These 1,486 centers represented 97,225 patients and 27,123 staff members. During the last 12 years, the incidence of HBV infection decreased from 3.0% to 0.2% among patients and from 2.6% to 0.1% among staff members. Over the same time, the prevalence of HBsAg-positivity declined from 7.8% to 1.7% among patients and from 0.9% to 0.4% among staff members. Hepatitis B vaccine was given by 88% of the centers. By the end of 1987, 14% of susceptible patients and 49% of susceptible staff members had received all three doses of hepatitis B vaccine. From 1982 to 1987, as a result of receiving vaccine, the prevalence of antibody to HBsAg (anti-HBs) increased from 12% to 18% among patients and from 18% to 50% among staff. The incidence of non-A, non-B hepatitis in 1987 was reported to be 1.2% among patients and 0.2% among staff members. Fourteen percent of the centers reported pyrogenic reactions among their patients, and 46% reported septicemia in the absence of pyrogenic reactions. Pyrogenic reactions were significantly more likely to be reported by centers that practiced high flux dialysis. The reported incidence of dialysis dementia among hemodialysis patients was 0.2%, with a case fatality rate of 29%. Among patients developing dialysis dementia, the case fatality rate was higher in those centers that used deionization (DI) without reverse osmosis (RO) (47%) compared with centers that used RO (28%) (not significant, p greater than 0.05). In 1987, 64% of centers reported that they reused disposable dialyzers. These centers treated 70% of the dialysis patient population.(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Effects of sealing of dentinal tubules of root canal wall with Ag (NH3)2F (3.8%) solution].

In this study, in order to determine a method for obtaining a good reaction, the reactive products of 3.8% Ag (NH3)2F, using formalin as a reducing agent, were studied. Saforide RC was used as the 3.8% Ag (NH3)2F solution and 10% neutral formalinsolution was used as a reducing agent. The silver mirror test and reaction products on the root canal wall were investigated under the scanning electron microscope, along with observation of dye penetration using a stereoscopic microscope. Reaction of periapical tissue to the materials was studied histologically in dogs. In the natural reduction group, less amounts of reactive products were seen, and sealing of the dentinal tubules of the root canal wall was inadequate. In the formalin reduction group, large amounts of reactive products were found, and the dentinal tubules of the root canal wall were sealed. CaF2, Ag3PO4, Ag2O and Ag were identified as reactive products. In the natural production groups, obstruction was present but incomplete. In Formalin groups, dye osmosis obstruction was recognized. No harmful action of the solution on the surrounding tissue of the dog's tooth was recognized.

Ammonium Compounds↗
PubMed1989

[Clinical analysis of bone diseases in patients under chronic hemopurification].

UNLABELLED: In this article are summed up the x-ray changes of bones, laboratory data and clinical manifestations of 62 patients treated by hemodialysis (HD), hemofiltration (HF) and HD plus HF alternately from 1978 to 1987. RESULTS: The incidence of bone disease reached 79% without significant difference between the three groups. The values of serum calcium, phosphate, alkaline phosphatase and carbon dioxide combining power (CO2CP) in these three groups were obviously abnormal. Three cases of bone necropsy showed aluminium deposits in bone tissues. We insist that to prevent the occurrence and worsening of bone disease during chronic hemopurification, reverse osmosis water should be used to prepare dialysates and substitution fluids. It is not advisable to use aluminum containing phosphate binder. The use of active VitD3 in the early stage, modulation of calcium content in dialysates, control of the intake of phosphates from foods, and giving desferrioxamine intravenously when necessary are helpful.

Adult↗
PubMed1988

[Significance of fluorides in chronic hemodialysis with reference to fluoridation of drinking water].

The metabolism of fluorides in impaired renal function is described. The use of fluoridized drinking-water in the production of dialysis fluid is discussed controversial. In patients treated by chronic hemodialysis the plasma fluoride level rises at a content of 1 mg fluoride per liter dialysis fluid. A relevant effect on the state of health is not certain established today. Therefore, it will be advised to the use of fluoride-free dialysis water. Its production should be made by use of a reverse-osmosis unit.

Fluoridation↗