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At least 991 records · Page 55Linked to original sources
PubMed1992

Comparison of standard and radionuclide methods for measurement of glomerular filtration rate and effective renal blood flow in female horses.

Comparison of standard and radionuclide methods for measuring glomerular filtration rate (GFR) and effective renal blood flow (ERBF) was performed in 8 healthy female horses. Inulin and p-aminohippurate solutions were administered IV as a bolus, followed by sustained administration. Urine and plasma inulin and p-aminohippurate concentrations and urine volume were measured. Glomerular filtration rate and ERBF were calculated on the basis of these measurements. Glomerular filtration rate and ERBF were measured on the basis of plasma clearance of the radiopharmaceuticals, 99mTc-labeled diethylene-triaminepentaacetic acid (99mTc-DTPA) and [131I]-o-iodohippuric acid (131I-OIH), respectively. Mean +/- SEM GFR, using inulin, was 1.83 +/- 0.21 ml/min/kg of body weight. Mean GFR, using 99mTc-DTPA was 1.79 +/- 0.18 ml/min/kg. Mean ERBF, using p-aminohippurate, was 15.13 +/- 1.28 ml/min/kg. Mean ERBF, using 131I-OIH, was 18.42 +/- 1.57 ml/min/kg. Analysis of variance indicated no significant difference between mean values for GFR and ERBF. Radionuclide measurement of GFR and ERBF compared well with standard methods and is an alternative technique to the cumbersome standard methods for determination of GFR and ERBF in horses.

Animals↗
PubMed2003

Direct filtration with preozonation for small water treatment systems.

The possibility of applying preozonation followed by direct filtration without the use of a coagulant is investigated. Filtration experiments have been carried out using four different water sources within Istanbul. A 1 m deep bed of 0.8-1.2 mm silica sand was used as the filter medium. The filter was operated at a rate of 11.5 m/hr. Raw water turbidities ranged from 2.3 NTU to 10.0 NTU. Effluent turbidity and particle count values were monitored using an on-line turbidimeter and an on-line particle counter. With all the waters studied in this work, preozonation improved particle removal in direct filtration. With three of the mentioned waters, it was possible to achieve turbidity values below 1.0 NTU without a coagulant by applying ozone at a rate between 1.7-1.8 mg/L. It was not possible to reduce the turbidity of one of the waters to below 2.7 NTU even with very high ozone dosages. The need for pilot testing before deciding if this treatment method is applicable to a given water is underlined.

Filtration↗
PubMed2004

The fundamentals of wastewater sludge characterization and filtration.

The move to greater emphasis on the disposal of wastewater sludges through routes such as incineration and the added cost of landfill emplacement puts high demands on dewatering technology for these sludges. A clear problem in this area is that wastewater sludges are slow and difficult to dewater and traditional methods of laboratory measurement for prediction of filtration performance are inadequate. This is highly problematic for the design and operational optimisation of centrifuges, filters and settling devices in the wastewater industry. The behaviour is assessed as being due to non-linear behaviour of these sludges which negates the use of classical approaches. These approaches utilise the linear portion of a t versus V2 plot (where t is the time to filtration and V is the specific filtrate volume) to extract a simple Darcian permeability. Without this parameter, a predictive capacity for dewatering using current theory is negated.

Biophysical Phenomena↗
PubMed2004

Clinical practice guidelines for chronic kidney disease in adults: Part II. Glomerular filtration rate, proteinuria, and other markers.

The Kidney Disease Outcome Quality Initiative of the National Kidney Foundation published clinical practice guidelines on chronic kidney disease in February 2002. Of the 15 guidelines, the first six are of greatest relevance to family physicians. Part II of this two-part review covers guidelines 4, 5, and 6. Glomerular filtration rate is the best overall indicator of kidney function. It is superior to the serum creatinine level, which varies with age, sex, and race and often does not reflect kidney function accurately. The glomerular filtration rate can be estimated using prediction equations that take into account the serum creatinine level and some or all of specific variables (age, sex, race, body size). In many patients, estimates of the glomerular filtration rate can replace 24-hour urine collections for creatinine clearance measurements. Urine dipsticks generally are acceptable for detecting proteinuria. To quantify proteinuria, the ratio of protein or albumin to creatinine in an untimed (spot) urine sample is an accurate alternative to measurement of protein excretion in a 24-hour urine collection. Patients with persistent proteinuria have chronic kidney disease. Other techniques for evaluating patients with chronic kidney disease include examination of urinary sediment, urine dipstick testing for red and white blood cells, and imaging studies of the kidneys (especially ultrasonography). These techniques also can help determine the underlying cause of chronic kidney disease. Family physicians should weigh the value of the National Kidney Foundation guidelines for their clinical practice based on the strength of evidence and perceived cost-effectiveness until additional evidence becomes available on the usefulness of the recommended quality indicators.

Adult↗
PubMed2004

Bank filtration: a suitable process for the removal of iodinated X-ray contrast media?

After bank filtration, effluent influenced surface waters are often used as raw drinking water. It is known that high concentrations of iodinated X-ray contrast media are detectable in such surface waters and thus, more knowledge about the behaviour of the contrast media during bank filtration is necessary and the subject of investigations in this study. The adsorbable organic iodine (AOI), four widely used iodinated X-ray contrast media and four possible transformation products were quantified in an influenced lake, five groundwater wells and a drinking water well. Under anoxic conditions the AOI as well as the concentration of the contrast media are decreased by bank filtration, whereby the AOI is decreased by 64% and the contrast media concentration can be reduced up to 95%, depending on the compound. In the raw drinking water the following average concentrations were determined: lopromid < 20 ng/L, Diatrizote 166 ng/L, lopamidol 166 ng/L and lohexol 34 ng/L. Instationary conditions during the sampling period indicate that, at least under anoxic conditions, a large part of the contrast media and transformation products, which are still iodinated, may be associated to colloids and/or humic material.

Colloids↗
PubMed2004

Sludge thickening performance of mesh filtration process.

Small-scale wastewater treatment facilities play an important role in improving the aquatic environment in many countries. Although sludge treatment is essential for overall wastewater treatment, it is difficult for small-scale facilities to use mechanical equipment or other facilities. As the first step of the sludge treatment, it is important to develop a convenient sludge thickening process for small-scale facilities. In this work, we examined the sludge thickening performance of a mesh filtration system: the mesh opening sizes of 100-500 microm, and the sludge (3,000-9,000 mg-SS/L) was obtained from a domestic wastewater treatment facility. The filtration was carried out only under the hydraulic pressure between the water level and the effluent port connected to the mesh filter module. The sludge reduction rates were in the range of 85-95% for 6-7 h; the initial filtration rate was very high, but the rate decreased with a decrease in hydraulic pressure due to the reduction of the water level in the vessel. In addition, the effluents (passed through the mesh) contained very low SS and could be directly discharged into the environment.

Facility Design and Construction↗
PubMed2004

Pattern of glomerular filtration rate abnormalities in type 2 diabetes mellitus in Jos, Nigeria.

BACKGROUND: Diabetes mellitus is one of the leading causes of end- stage renal disease in Nigeria. OBJECTIVES: To describe the pattern of glomerular filtration rate abnormalities and its clinical correlates in Nigerians with type 2 diabetes mellitus. METHODS: Glomerular filtration rate as determined by the endogenous creatinine clearance was measured in 90 patients with type 2 diabetes mellitus and 60 controls at the Jos University Teaching Hospital, Jos. RESULTS: Twelve subjects (13.3% ) in the diabetic group had hyperfiltration (GFR > 125 ml/min) compared to 3 (5% ) in the control group, although the mean glomerular filtration rates were similar in the two groups (96.19 +/- 29.14 ml/min and 88.38 +/- 24.13 ml/min respectively, p > 0.05). All the subjects with hyperfiltration had been diabetic for less than 5 years. Only one of the diabetics had renal insufficiency (GFR < 50 ml/min). CONCLUSIONS: This study demonstrates that hyperfiltration is common in patients with type 2 diabetes mellitus and that it occurs early in the course of the disease.

Adult↗
PubMed2001

[Cystatin C in estimates of glomerular filtration in patients with renal disease--initial experience].

Cystatin is reported in the literature with increasing frequency as a new reliable parameter for estimates of glomerular filtration. The authors examined cystatin C by the PET method of DAKO Co. in 151 patients from the nephrological out-patient clinic. 91 patients had normal renal functions, 60 suffered from renal insufficiency of different severity. Between cystatin C and glomerular filtration assessed by creatinine clearance was a close correlation, R = -0.787 according to Pearson. The authors evaluated separately a group of 36 patients with glomerulonephritis, 34 diabetic patients with diabetic nephropathy, 38 patients with tubulointerstitial nephritis and 43 subjects with other kidney diseases. The groups did not differ significantly when compared with the whole group nor mutually (p = n.s.). The authors of the study confirmed that a good correlation of cystatin with creatinine filtration is not influenced by the type of basic nephrological disease. The effect of administration of insulin, antihypertensive drugs, cyclosporin A and glucocorticoids was not proved in the investigated group. The published method is accurate, not demanding from the technical aspect. The examined subject is not restricted by conditions ensuring the accuracy of assessment and seems thus useful and perspective for nephrological patients.

Adult↗
PubMedDate not supplied

[Role of filtration in localization of the evoked potential dipoles in the human brain: experiment and simulation].

3D dipole tracing with 1 ms step of visual evoked potentials recorded from 40 electrodes was performed under exposition of crosses in 5 healthy human subjects. The data on dipole displacement were compared with prediction of the simulation study on distortion of dipole localization by the signal filtration in the low-frequency band. These predictions were experimentally confirmed: the effect depends on the degree of filtration (0.1 or 0.5 Hz) and on the latency of EP waves. Localization and strength of P1 dipoles were not changed under filtration, while for later components--N2 and especially P3--they changed significantly. For the improvement of these distortions time constant of the amplification tract must be some times longer than the time of the dipole activity.

Brain↗
PubMedDate not supplied

[Purification of lake water using a combined ozonization, filtration and chlorine dioxide treatments. Experience with the water of Garda lake].

The hygienic characteristics of the freshwater from Garda Lake used for the water supply of Sirmione were evaluated before and during the various phases of treatment. The samples were taken at the moment of entry, after ozonization, after filtration and after the addition of chlorine dioxide. The coliforms and Escherichia coli, occasionally detected in the incoming water, were reduced by ozone and eliminated by filtration. Enterococci were always absent. The overall reduction in the total bacteria count was satifactory, considering the low initial levels (96.0% and 83.0% respectively for the Heterotrophic plate count at 22 degrees and the Heterotrophic plate count at 36 degrees). The chemical and physical indicators that underwent the greatest reductions were the sulphates, iron, manganese, ammonia and the turbidity. Several species of unicellular algae belonging to Chlorophyta, Cyanophyta and Bacillariophyta were identified in the water at entry and after ozonization, but were completely eliminated during the subsequent phase of filtration. deliver of high quality services.

Chlorine Compounds↗
PubMed2006

[Comparison of sludge filtration characteristics between a membrane bioreactor and a conventional activated sludge process].

According to the filtration characteristics of sludge, a comparison between a membrane bioreactor (MBR) and a conventional activated sludge process(CAS) was carried out under similar conditions. Experiment results show that the filtration resistance in MBR was 2 to approximately 3 times of that in CAS. The contribution of supernatant resistance to filtration resistance was about 90% both in CAS and in MBR. The test on resistance distribution showed the cake resistance made up 87.30% and 94.18% of total resistance in CAS and MBR, respectively.

Biodegradation, Environmental↗
PubMed1991

Somatostatin analogue, octreotide, reduces increased glomerular filtration rate and kidney size in insulin-dependent diabetes.

To determine whether treatment with a somatostatin analogue can reduce kidney hyperfiltration and hypertrophy in insulin-dependent diabetes mellitus, we studied 11 patients with insulin-dependent diabetes mellitus and glomerular hyperfiltration. The patients were assigned randomly to receive continuous subcutaneous infusion of either octreotide, 300 micrograms/24 h (five patients) or placebo (six patients) for 12 weeks. At baseline, mean glomerular filtration rate and mean total kidney volume were not significantly different in the two groups. However, after 12 weeks of treatment, the mean glomerular filtration rate was significantly lower in the octreotide group (136 mL/min per 1.73 m2; range, 91 to 158 mL/min per 1.73 m2) than in the placebo group (157 mL/min per 1.73 m2; range, 138 to 184 mL/min per 1.73 m2). Furthermore, the mean total kidney volume was significantly lower after treatment in the octreotide group (379 mL/1.73 m2; range, 307 to 454 mL/1.73 m2) than in the placebo group (389 mL/1.73 m2; range, 347 to 465 mL/1.73 m2). Glycemic control did not change significantly in either group. We conclude that subcutaneous infusion of octreotide for 12 weeks reduces increased glomerular filtration rate and kidney size in patients with insulin-dependent diabetes mellitus despite the fact that glycemic control remains unchanged.

Adult↗
PubMed1991

[Characterization of erythrocyte deformability by filtration technics. 5. The effect of leukocytes on the filterability of erythrocytes].

Filterability measurements have been used widely in medical research and clinical practice to characterize erythrocyte deformability. In the present paper the influence of white blood cells (WBC) on the of filterability indices is investigated and discussed. We found for two gravity filtration systems using cellulose filters and concentrated erythrocyte suspensions sensitivities of their filterability indices of 1% per 100 WBC/microliters (initial) filtration rate measurement) and 3% per 100 WBC/microliters (hemofiltrometer). The necessity, advantages and disadvantages of additional methods for WBC removal are discussed in comparison to nuclepore filtration systems with sensitivities of 5-12% per 100 WBC/microliters. The standardization of residual WBC-count in limits of 500 +/- 300 WBC/microliters at a hematocrit of 60% is proposed.

Erythrocyte Deformability↗
PubMed1990

Mechanisms of amphotericin B-induced reduction of the glomerular filtration rate: a micropuncture study.

Amphotericin B infusions cause acute reductions in renal plasma flow and glomerular filtration rate. The exact mechanism by which these changes occur has not been identified fully, nor have the effects of the drug on the renal microcirculation been studied adequately. In this study, we examined the effect of intrarenal amphotericin B infusions (0.05 mg/kg/min) on glomerular hemodynamics in the anesthetized rat. Amphotericin B did not affect systemic blood pressure and slightly increased hematocrit (5%), but significantly decreased renal blood flow and glomerular filtration rate by 40 and 35%, respectively. Glomerular micropuncture revealed decreases in single nephron plasma flow and glomerular filtration rate (from 142 +/- 12 to 89 +/- 14 and from 35.3 +/- 2.2 to 22.8 +/- 2.8 nl/min, respectively). These changes were due to significant increases in pre- and postglomerular resistances (from 1.91 +/- 0.17 to 3.95 +/- 0.38 and from 1.30 +/- 0.10 to 2.08 +/- 0.12 10(10) dyn.sec.cm-5, respectively), and to a significant decrease in the glomerular capillary ultrafiltration coefficient which fell from 0.043 +/- 0.008 to 0.032 +/- 0.009 nl/(sec.mm Hg). These results provide further insight into the mechanisms of the acute renal effects of amphotericin B, and suggest possible mediators that may be involved in these effects.

Amphotericin B↗
PubMed1989

Stability of pibenzimol hydrochloride in commonly used infusion solutions and after filtration.

The stability of pibenzimol hydrochloride was evaluated after reconstitution, after addition to several intravenous fluids, and after filtration. Vials containing pibenzimol hydrochloride 50 mg were reconstituted with 2.5 mL of 0.9% sodium chloride injection to 20 mg/mL. For determination of drug stability in intravenous fluids, vial contents were further diluted to 0.15 mg/mL by injection into glass containers and polyvinyl chloride (PVC) bags containing 250 mL of 5% dextrose injection, 0.9% sodium chloride injection, or lactated Ringer's injection. Pibenzimol concentrations were determined immediately after preparation and at various intervals after storage at 4-6 degrees C or 25 degrees C by means of a stability-indicating, high-performance liquid chromatographic technique. Vial contents were inspected visually for color changes, and pH was measured. Determinations were also made of the stability of pibenzimol 0.15 mg/mL in 0.9% sodium chloride injection after simulated infusions using a 0.22-micron filter set at 25 degrees C. All study solutions and admixtures retained more than 90% of the initial pibenzimol concentration. The greatest loss of drug (6-7%) occurred after 24 hours in lactated Ringer's injection in both glass and PVC containers and in 0.9% sodium chloride injection in PVC bags. No drug loss occurred as a result of filtration. Reconstituted pibenzimol hydrochloride and admixtures of pibenzimol in 5% dextrose injection, 0.9% sodium chloride injection, or lactated Ringer's injection in glass or PVC containers are stable for at least 24 hours at 25 degrees C. Filtration has no effect on stability.

Benzimidazoles↗
PubMed1989

[Effects of hypophysin and desoxycorticosterone-21-acetate on renal function in calves in the neonatal period. I. Diuresis volume, glomerular filtration rate and urinary excretion of endogenous creatinine].

Experiments concerning the influence of hypophysin (0.1 vol. unit/kg) and desoxycorticosterone-21-acetate (0.1 mg/kg) on the size of diuresis, urine condensation and the glomerular filtration process have been carried out on 12 bulls at the age of 2-5 weeks of life. It has been stated that already 2-week old kidneys are able to condensate urine, and kidney water saving under the influence of hypophysin is the result of glomerular filtration decrease and tubular resorption increase. Water and electrolytes stopping under the desoxycorticosterone-21-acetate influence was caused by lowered glomal leaking and intensified process of adsorption in tubules. The lack of higher acidification of urine after acetate injection suggests that kidneys at neonatal period show low activity "re serve" within acid-alkaline balance regulation. It has been pointed out that because of intensive tubular secretion the clearance of endogenous creatinine cannot be the measure of glomerular filtration size.

Animals↗
PubMed1989

[The effect of glass wool filtration on human spermatozoa--a comparison with the swim-up technic].

20 fresh human ejaculates (6X normozoospermia, 7X oligozoospermia and 7X asthenozoospermia) were prepared either with the swim-up-method as with the glass wool filtration. After both techniques the motility of the spermatozoa improved markedly. In cases of asthenozoospermia and oligozoospermia the motility increased significantly compared with the value of the ejaculate. From the motile spermatozoa of the ejaculate 45-60% were detectable in the filtrat after glass wool filtration or in the upper fluid after swim-up-procedure.

Female↗
PubMed1989

Air filtration: protection against respirable dust.

The principal health hazard associated with airborne dust is attributable to particles with aerodynamic diameters of a few micrometers or less, and filtration is, in principle, a good way of obtaining protection against such small particles. The elements of filtration theory can be deduced from simple arguments, which illustrate that it is difficult to remove particles that are 1 or 2 microns in diameter from air by filtration using a filter made from ordinary textile fibres. Either much finer or electrically charged fibres must be used and, in general, the latter solution is preferable. A number of different electrically charged filter materials exist, examples of which are materials that are charged triboelectrically, by corona, or by induction. The mechanism of action of these materials is described, along with conditions necessary for their successful use.

Air Pollution↗