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PubMedDate not supplied

Comparison between swim-up and glass wool column filtration of human semen in a gamete intrafallopian transfer program.

This study compared swim-up and glass wool filtration in both pregnancy outcome and fertilization of excess oocytes in patients undergoing gamete intrafallopian transfer. Gamete intrafallopian transfer patients were retrospectively included in the study group (n = 52). The criteria for inclusion were as follows: Semen had to have been prepared by means of glass wool filtration and at least 2 metaphase II oocytes had to have been transferred. Each patient from this group was then carefully matched with another patient according to specific criteria (number of metaphase II oocytes aspirated and transferred, normal sperm morphology, wife's age, the absence of anti-sperm antibodies, semen preparation by means of the swim-up procedure). Fourteen patients were matched with themselves (groups A1 and A2) and 38 patients were matched with another patient (groups B and C). The results indicate that there was no significant difference in the fertilization and pregnancy probabilities of sperm prepared by means of glass wool filtration or swim-up procedure. The comparative pregnancy rates for the groups were A1 (7.1%) versus A2 (7.1%) and B (28.9%) versus C (31.6%). Factors other than fertilization and pregnancy potential may have a greater influence on choosing the optimum sperm preparation procedure.

Female↗
PubMed1981

Connection between the changes in tubular reabsorption and in glomerular filtration rate induced by replacement of plasma sodium and chloride by isotonic mannitol.

Glomerular filtration and tubular reabsorption have been investigated comparatively in isolated blood-perfused dog kidneys, after addition to the blood of equal volumes of isotonic sodium chloride or isotonic mannitol. In the absence of antidiuretic hormone activity, the urine output showed no significant difference, while the glomerular filtration rate was lower in the presence of the mannitol load. The inhibition of fluid reabsorption was compensated by the decrease of filtration; a quantitative tubulo-glomerular equilibrium was evidenced. The fractional sodium excretion was decreased following the dilution by the mannitol load of plasma sodium and -chloride; this difference disappeared when the reabsorption in the diluting segment was inhibited by furosemide, suggesting that it depended on the rate of chloride reabsorption in this part of the tubule.

Animals↗
PubMed1989

A new red blood cell filtration device with improved time resolution and its application to the impaired RBC deformability in the diabetic ob/ob mouse.

A new filtration device and blood handling technique for the assessment of RBC deformability in small blood samples is described and used to study RBC deformability in adult obese-hyperglycemic ob/ob-mice and normoglycemic controls. The new filtration device was designed to improve the time resolution during RBC incubation. Test and control RBC suspensions were directly filtered from two identical incubation chambers under a constant pressure of 1200 Pa. Nuclepore filters (3 microns) were mounted on top of several standard test tubes into which the filtrate was subsequently collected and weighed. Because the RBCs were resuspended to a very low (0.01%) hematocrit, the average number of RBCs passing each pore was less than 10. Therefore, any detectable difference must reflect the physical properties of RBCs, e.g. shape or viscoelasticity, whereas the role of white blood cells is negligible. When ob/ob-mouse RBCs were studied with the new technique they showed impaired filtrability as compared with control RBCs, both when incubated without glucose and with glucose present at the same concentration as that recorded in the RBC donating mouse.

Animals↗
PubMed1982

Laboratory and field evaluation of a direct filtration technique for recovery of schistosome cercariae.

The use of cercariometry in epidemiological studies has been limited by turbidity, difficulty of recovering cercariae at low concentrations in natural waters, and by complex apparatus that requires a power source. The technique of differential filtration developed by Theron has been modified and tested in the laboratory and in the field in Upper Egypt for detection of Schistosoma haematobium cercariae. A recovery filter with a pore size of 30 micrometer was found to give the best results. The recovery rate in the laboratory was 51% on filtration of 5-liter samples of formalin-treated water, and 19-30% with 10- and 20-liter samples. This moderate efficiency is offset by simplicity of the technique, rapid filtration, and ease of reading the recovery filter, permitting sampling of large volumes of water in the field by persons with little training. Average densities of 0.024 cercariae per liter of water were found at the Nile and 0.029 cercariae per liter in the irrigation canals. Most cercariae were recovered between 0.700 and 0900 hours.

Animals↗
PubMed2000

Antimicrobial properties of pepsin-digested lactoferrin added to carrot juice and filtrates of carrot juice.

The objective of this study was to determine the antimicrobial activity of pepsin-digested lactoferrin added to carrot juice and filtrates prepared from carrot juice. Lactoferrin isolated from raw skim milk was digested by pepsin for 4 h at pH 3. The digest of lactoferrin was lyophilized, and the antimicrobial activity of the digests was determined in peptone-yeast-glucose broth, carrot juice, permeate from carrot juice, and the dialysate of carrot juice permeate using Escherichia coli (American Type Culture Collection strain 35343) as the test organism. Growth of E. coli and the inhibitory effect of the peptide were greater in peptone-yeast-glucose broth at pH 7 than at pH 4. The peptic digest of lactoferrin did not have antimicrobial properties in carrot juice at concentrations of less than 10 mg/ml of juice. Carrot juice was filtered through a membrane with a molecular weight rejection of 10,000 or 500 Da, and the permeate was dialyzed against distilled water. Growth of E. coli was delayed in the filtrate by 5 mg but not by 1 mg of the peptic digest of lactoferrin per ml of filtrate. Bacterial counts of the control and experimental samples were not significantly different after 24 h of incubation. The peptic digest of lactoferrin at a concentration of 5 mg of digest per ml of dialysate was bacteriostatic toward E. coli after 24 h of incubation at 23 degrees C. Dialysis of permeate caused a percentage reduction in cation concentration in the permeate ranging from 69.23% (Co) to 99.32% (Na). The antimicrobial activity of lactoferrin added to carrot juice was probably inhibited by cations.

Animals↗
PubMed2001

Quantitative microbiologic study of blood salvaged by intraoperative membrane filtration.

OBJECTIVE: To evaluate the sterility of blood salvaged intraoperatively by a new membrane filtration system for transfusion. DESIGN: Quantitative microbiologic cultures were prospectively collected from units of blood acquired by intraoperative membrane filtration from 18 patients undergoing elective spinal surgery. Medical records were reviewed for adverse events. SETTING: A 204-bed, medical school-affiliated community hospital. RESULTS: Quantitative blood cultures were sterile in 12 of 31 units of recovered blood. Of the 19 positive units, 17 units grew only 1 colony-forming unit (CFU)/mL, 1 unit grew 2 CFU/mL, and 1 unit grew 5 CFU/mL. The only organisms isolated were diphtheroids, coagulase-negative staphylococci, and micrococci. No patient experienced postoperative sepsis. CONCLUSIONS: Blood recovered by intraoperative membrane filtration is microbiologically equivalent to blood salvaged by continuous flow. Because no perfusionist and no expensive capital equipment are required, the technique is amenable to small and medium-sized hospitals that otherwise might financially be unable to provide intraoperative blood salvage.

Adult↗
PubMed1999

[Measurement of glomerular filtration rate in connection with 99Tc-DTPA renography].

Glomerular filtration rate (GFR) was measured in two groups of cancer patients. In 20 patients, glomerular filtration rate was measured simultaneously with 51Cr-EDTA, 99mTc-DTPA and the X-ray contrast agent iohexol as markers, and with a complete set of eight blood samples during 24 hours. In a second group of 120 patients, we used 99mTc-DTPA only and tested various simplified methods, based on one or two blood samples. Glomerular filtration rate was also calculated from serum creatinine. There was excellent agreement between the values measured with the three markers, and, in the same group of patients, very good agreement with the results of simplified methods. The larger study carried out with 99mTc-DTPA on the second group of patients, confirmed a very good agreement between methods based on the slope of the plasma curve and a method based on one blood sample only. The correlation was worse between the values obtained by any of the radionuclide methods and those calculated from serum creatinine. The latter method should therefore not be used for determination of renal function.

Chromium Radioisotopes↗
PubMedDate not supplied

Effect of diabetes mellitus on glomerular filtration rate in an urban hospital diabetic population.

Glomerular filtration rate (GFR) as assessed by endogenous creatinine clearance was studied in 46 male and 38 female patients with diabetes mellitus (DM). Of these, 44 patients had uncomplicated DM (Group I) whilst 40 patients had complicated DM (Group II). There were 20 insulin-dependent diabetes mellitus (IDDM) patients in Group I and 5 in Group II, and 24 non-insulin dependent diabetes mellitus (NIDDM) patients in Group I and 35 in Group II. In Group I, 6 IDDM and 4 NIDDM patients had supranormal glomerular filtration rate (creatinine clearance 125 ml/min) and in Group II 1 IDDM and 6 NIDDM patients had supranormal GFR. The presence of diabetic complications and the mode of therapy of the diabetic state did not significantly affect the glomerular filtration rate. This concludes that glomerular hyperfiltration occurred in both IDDM and NIDDM Nigerian patients.

Adolescent↗
PubMedDate not supplied

The effects of water filtration systems on fluoride: Washington, D.C. metropolitan area.

According to the U.S. Environmental Protection Agency (EPA), approximately one in eight Americans is exposed to potentially harmful microbes, pesticides, lead, or radioactive radon whenever they drink a glass of tap water or take a shower. One reason for this exposure is that the water plants are aging or ill equipped to process the huge amounts of raw sewage and agricultural pollutants that are still being discharged into our drinking-water sources. Other compounds such as fluoride and chloride have been added to the community water supplies for health benefits. Water filtration systems are becoming more popular as people become concerned with pollutants in the public water supply and questions are being raised as to whether fluoride is affected by these filters. The aim of this pilot study was to assess the efficacy of three types of water filtration systems and to determine their impact on fluoride content of the water in the Washington, D.C. metropolitan area. One sample of water was collected daily for fourteen days, from one location. The sample was divided to use as a control and the test samples which were processed through various filter systems. With the use of a fluoride ion specific electrode, the fluoride concentration level was tested in all samples in order to determine the percentage of fluoride removed. This study was intended to prove that the water filtration systems did not affect the advantage offered by optimum water fluoride levels. The experimental samples were ascertained and compared to the control group, resulting in three of the four carbon filters showing statistically significant amounts of fluoride removed from the water. Both Reverse Osmosis and Distillation, as expected, removed the fluoride at a high rate.

District of Columbia↗
PubMed1975

[Determination of the filtration characteristics of the fermentation broths of antibiotic producers].

Main filtration characteristics of the fermentation broths are necessary for estimation of the filtration equipment, rational choice of the filtering apparatus, determination of the optimal conditions for their exploitation. In this connection studies were carried out with a purpose of determining the specific resistance and the content of the solid phase in the fermentation broths of the main antibiotics. It was shown that the above characteristics were closely connected with the biosynthetic conditions and medium composition. It was noted that the specific resistance of the precipitates of the fermentation broths of various antibiotic-producing organisms significantly differed, sometimes by several orders. Preliminary treatment of the fermentation broths before filtration provided a marked decrease in the resistance of the precipitate.

Actinomycetales↗
PubMed2001

Direct influent filtration as a pretreatment step for more sustainable wastewater treatment systems.

Within the scope of a research programme into wastewater treatment scenarios based on physical-chemical pretreatment, the application of direct influent filtration (DIF) as a first treatment step in a wastewater treatment system was investigated. The aim of the experimental research was to investigate the feasibility of DIF as a pretreatment step for advanced particle removal. With a large scale pilot-plant filter at WWTP Leiden-Noord, The Netherlands the removal characteristics for suspended and colloidal material were investigated as well as operational conditions of eight different filter configurations. From the experimental research it was concluded that filtration of raw wastewater is possible, notwithstanding the relatively short run-times due to clogging. In general, the filters produced a filtrate with a constant quality with low concentrations of solids and low turbidity. Without addition of chemicals hardly any colloids and solubles were retained, but only suspended particulates were removed. After dosage of iron or polymer, it was possible to remove more suspended matter and a high proportion of colloidal material. Finally it was concluded that DIF could be applied as a compact treatment system to produce a high quality primary effluent with a constant composition, but for practical application further research has to be done.

Conservation of Natural Resources↗
PubMed2001

Electron beam computerized tomography assessment of in vivo single kidney glomerular filtration rate and tubular dynamics during chronic partial unilateral ureteral obstruction in the pig.

PURPOSE: The assessment of hydronephrosis due to chronic partial ureteral obstruction is controversial. We determined whether a new radiographic technique for assessing kidney function, electron beam computerized tomography (CT), can detect altered renal physiology due to chronic partial ureteral obstruction. We also compared and contrasted electron beam CT with standard well tempered diuretic mercaptoacetyltriglycine (MAG-3) urography. MATERIALS ANDS METHODS: Six pigs underwent creation of unilateral partial ureteral occlusion or sham operation. Three weeks after surgery diuretic enhanced MAG-3 renal scan was done and 48 hours later contrast enhanced electron beam CT was performed. RESULTS: Mean differential function plus or minus standard error of mean of the obstructed kidney was 5.6% +/- 2.4% on MAG-3 renography. In contrast, electron beam CT revealed significantly preserved mean renal function at 24.5% +/- 2.7% (p <0.01). Electron beam CT analysis of tubular function revealed persistent glomerular filtration and filtrate flow through the proximal tubules and loop of Henle with a selective decrease in distal tubular flow, which were findings suggestive of proximal tubular sparing that were not demonstrated by nuclear renography. CONCLUSIONS: Renal function on MAG-3 renography is primarily determined by measuring kidney perfusion and tubular secretion of the isotope. In contrast, electron beam CT determines renal function via quantifying the in vivo single kidney glomerular filtration rate and by assessing renal tubular function. This study documents that electron beam CT of differential renal function is significantly different from that of MAG-3 renography. To our knowledge which of these 2 radiographic studies is most clinically applicable is unknown to date.

Animals↗
PubMed2001

Effect of particle size on the performance of batchwise centrifugal filtration.

The effect of particle size distribution on the performance of batchwise centrifugal filtration is studied. By analyzing the velocity of particles in a filter, a numerical program is designed for simulating the migration and deposition of particles. The particle size distributions and the average specific filtration resistances of cake are then estimated under various rotating speeds of the centrifuge. A large deviation of particle concentration profiles in the filter chamber will occur if the particle size distribution is not taken into consideration. A more heterogeneous cake will form under a lower rotating speed due to the sedimentation effect of particles. The predicted results of particle size distribution and average specific filtration resistance of cake agree well with the available experimental data.

Centrifugation↗
PubMed1975

[Effect of the degree of dilution of the antibiotic fermentation broths on the filtration indices].

Dilution of the fermentation broths with water before the mycelium separation lowered the specific cake resistance. The effect of the dilution on the filtration duration was different and depended on the fermentation broth type. As for the erythromycin fermentation broth, the time of its filtration decreased after the dilution, while the filtration time of the fermentation broths of the other 2 antibiotic-producing organisms increased after the dilution.

Anti-Bacterial Agents↗
PubMed2002

[The value and adaptability of glomerular filtration rate and reserve test (review of the literature)].

In normal conditions only 75% of kidney function capability are in use. Resting part of kidney function is called renal functional reserve. It is a very important indicator for prediction of renal insufficiency in chronic renal diseases, morphological changes or reduced mass of kidney parenchyma. More common test to estimate renal functional reserve is a method of measurement of glomerular filtration rate (clearance) before and after provocation of renal filtration by acute peroral protein load. The value and the possibilities to put in practice this test as well the factors influencing the results of glomerular filtration rate were estimated in this review.

Circadian Rhythm↗
PubMed2003

Removal of microbes from municipal wastewater effluent by rapid sand filtration and subsequent UV irradiation.

The elimination of wastewater microbes is often necessary when effluent receiving waters are reused for different purposes e.g. for irrigation or as a raw water source of drinking water. In the present study, rapid sand filtration (SF) combined with the use of polyaluminium chloride coagulation was used as a pre-treatment to improve the quality of wastewater effluent before further treatment with UV irradiation. Pilot-scale experiments were run in four treatment plants in Finland. Treatment performance was followed by measuring physical and microbial parameters. Rapid sand filtration reduced suspended solids, turbidity and colour of effluents by about 90%, 70-80% and 20-50% respectively. It also improved the UV transmittance of water by up to 20%. Microbes and phosphorus were reduced by 90-99% and to 0.05 mg/L respectively. UV irradiation further reduced the number of microbes up to 99.9%. The efficiency of UV doses in pilot UV reactors was confirmed with collimated-beam device determinations and with added FRNA phages. More than 99.9% reduction of MS2 was achieved with the dose of 140mWs/cm2 in pilot UV reactors. Rapid sand filtration and the subsequent UV irradiation reduced the number of all the tested microbes to a low level, often below the detection limit. Suspended solids and the water turbidity were reduced to 1-2 mg/L and approximately 1 NTU respectively.

Agriculture↗
PubMed2003

[Filtration capability of the bio-dynamic membrane].

The filter modules made of common mesh material were submerged in to a bioreactor to form a dynamic-membrane bioreactor. This paper studied the filtration capability of the dynamic bio-membrane forming on 100-micron Dacron mesh material. The outstanding solid-liquid separation capability of the dynamic bio-membrane was mainly contributed to the gel-layer attaching on the mesh material. The dynamic bio-membrane could checked 30%-60% TOC of various molecule weights ranging < 3000 to > 10(5), whereas its separation accuracy was not high enough to intercept all the organics of molecules weights larger than 10(5). The tap water filtration resistance of the dynamic bio-membrane sheet with gel-layer attaching on was about 1.9 x 10(9) m-1, which almost equaled to that of the untapped sheet. The resistance caused by cake-layer contributed about 70% to the total filtration resistance of the dynamic bio-membrane on working. The untapped dynamic bio-membrane sheet showed an initial resistance to tap water permeation, but the one with gel-layer attaching on had little initial resistance. The reason might be that the gel-layer eliminated the hydrophobicity of the mesh material.

Bioreactors↗
PubMed1992

[Nephrotoxic effect of gentamicin on the function of the proximal tubules of the nephron and glomerular filtration].

The purpose of the study was assessment of gentamicin nephrotoxicity with reference to proximal tubule function and glomerular filtration. The study was carried out in 20 patients with nephrolithiasis and chronic pyelonephritis, and 33 patients with respiratory and bile tract infections treated with gentamicin in doses of 2-3 mg/kg/2 h. In 3 patients with nephrolithiasis and chronic pyelonephritis signs of increased nephrotoxicity of gentamicin (according to Schentag criteria) were found. Similar signs were demonstrated in 3 patients with non-urinary tract infections. The abnormalities included increased excretion of low-molecular protein and beta-2-microglobulin (B2m), reduction of B2m reabsorption and lower glomerular filtration. Beta-2-microglobulinuria increase precede by 4-5 days the fall of the glomerular filtration rate which suggests that beta-2-microglobulinuria assessment is an early sign of gentamicin neurotoxicity.

Adult↗