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At least 19 recordsLinked to original sources
PubMed1979

Concentration of poliovirus from tap water using positively charged microporous filters.

Microporous filters that are more electropositive than the negatively charged filters currently used for virus concentrations from water by filter adsorption-elution methods were evaluated for poliovirus recovery from tap water. Zeta Plus filters composed of diatomaceous earth-cellulose-"charge-modified" resin mixtures and having a net positive charge of up to pH 5 to 6 efficiently adsorbed poliovirus from tap water at ambient pH levels 7.0 to 7.5 without added multivalent cation salts. The adsorbed virus were eluted with glycine-NaOH, pH 9.5 to 11.5. Electropositive asbestos-cellulose filters efficiently adsorbed poliovirus from tap water without added multivalent cation salts between pH 3.5 and 9.0, and the absorbed viruses could be eluted with 3% beef extract, pH 9, but not with pH 9.5 to 11.5 glycine-NaOH. Under water quality conditions in which poliovirus recoveries from large volumes of water were less than 5% with conventional negatively charged filters and standard methods, recoveries with Zeta Plus filters averaged 64 and 22.5% for one- and two-stage concentration procedures, respectively. Electropositive filters appear to offer distinct advantages over conventional negatively charged filters for concentrating enteric viruses from water, and their behavior tends to confirm the importance of electrostatic forces in virus recovery from water by microporous filter adsorption-elution methods.

Adsorption↗
PubMed1979

A rapid, semi-automated procedure for the evaluation of leukocyte locomotion in the micropore filter assay.

A commerically available bacterial colony counter has been modified to allow rapid, accurate, semi-automated evaluation of cell numbers in the micropore filter assay for chemotaxis. The method is valuable for objective, rapid evaluation of cell counts at various levels through the filter, as well as counts on the distal surface of the filter. Coupled with a programmable calculator, this instrument had made feasible a new method of assessing random migration by the regression line analysis, which discriminates between migration rate and mass migration of cells. This combination of equipment may thus serve as a considerable time saving accessory to laboratories engaged in cell locomotion research, but also will allow more rigorous assessment of differences among specific populations of cells.

Analysis of Variance↗
PubMed1975

Comparative study of four microporous filters for concentrating viruses from drinking water.

Four microporous virus-absorbent filter media for recovering low levels of virus from 380 liters of drinking water were compared. In addition two of the filter media were compared with 1,900 liters of drinking water. The filter media evaluated were MF nitrocellulose membranes (293 mm), AA Cox M-780 epoxy-fiberglass-asbestos disks (267 mm), K-27 yarn-wound fiberglass cartridges + AA Cox M-780 disks (127 mm), and Balston epoxy-fiberglass tubes (24.5 by 63.5 mm). The filters were used to concentrate seeded poliovirus from 380 liters of finished drinking water. Sodium thiosulfate was added to the drinking water to neutralize chlorine, and hydrochloric acid was added to adjust the pH to 3.5. Virus was eluted from the filters with glycine-NaOH buffer at pH 11.5. In terms of virus recovery efficiency, the filter media ranked Balston greater than Cox 267-mm greater than MF 293-mm congruent to K-27 + Cox 127-mm, but differences were slight. The Balston filters and holders were also superior to the other systems in terms of size, weight, cost, and handling factors. Experiments with 2- and 8-mum porosity Balston filters showed no statistically significant difference in virus recovery. Virus was readily detected by the Balston and the MF 293-mm systems at input levels of 12 to 22 PFU/1,900 liters. Preliminary experiments indicated that an elution pH lower than 11.5 may be satisfactory.

Asbestos↗
PubMed1977

[Is there an indication for the use of "micropore-blood filters"? (AUTHOR'S TRANSL)].

Recently "micropore" blood transfusion sets have been advocated to replace the traditional transfusion sets. Because of the higher cost it is important to review critically the data which would justify their clinical use. The filters eliminate microaggregates as they occur during blood storage. The question is wether micropore filters are able to reduce the incidence of posttraumatic or postoperative respiratory insufficiency. We have analysed all controlled in vivo studies. We found only one clinical study where in massively transfused polytrauma patients a decrease in the number of cases of respiratory insufficiency was documented. However, due to the small number of patients investigated, a significant difference in favour of the micropore filters could not be demonstrated. Animal experiments reveal more: Exchange transfusions carried out in dogs through micropore filters do not lead to functional or morphological pulmonary changes. Using traditional transfusion sets, a significant increase in pulmonary artery pressure and resistance was found together with a decrease in arterial pO2, pH and oxygen consumption. All these results correlate well with morphological changes in the lung. On the basis of our literature review, we conclude that there are no clear data which would make it mandatory to use micropore filters in clinical practice. On the other hand, there are several indirect hints than large amounts of microaggregates are not ideal for pulmonary function. The expensive micropore filters could therefore perhaps be used with advantage in massive tranfusions.

Animals↗
PubMed1977

[The effectiveness of various micropore blood filters (author's transl)].

Recently so-called micropore blood transfusion filters have been introduced. They should decrease the number of microemboli produced by blood transfusion and thus decrease the incidence of postoperative and posttraumatic pulmonary insufficiency. Since these filters are rather expensive and several types and models are offered, it seemed to us important to review their properties and the results obtained with the most commonly used models (Pall, fenwal, Swank and Bentley). The efficacy of the various filters is apparently quite different. Depending on the indication, the use of different filters is possible. There is no filter which fulfils all prerequisites which must be made for an ideal micropore filter. On the basis of our literature review we conclude that filters made of Dacron wool are best suited for all purposes. There are no good reasons to use these micropore filters routinely for all blood transfusions. However, when large amounts of blood must be given rapidly and pulmonary function is already reduced, the use of micropore filters routinely for all blood transfusions. However, when large amounts of blood must be given rapidly and pulmonary function is already reduced, the use of micropore filters seems reasonable.

Blood↗
PubMed1977

[Determination of antimony from environmental air in the working area using flameless atomic absorption with a graphite furnace].

Particulates of antimony present in area of plants producing a catalyst containing iron an antimony have been determined. The environmental aereosol, filtered through micropore filters, is analyzed in the form of stabilized aqueous suspension by atomic adsorption flameless graphite furnace. The limit of air revealability permitted by the method is 0.2 mcg/m3. With the above mentioned revealability limit it is possible to perform very rapid drawings of environmental air, so that noxiouslity of even very short-time processing can be controlled.

Air Pollutants↗
PubMed1977

[Atmospheric concentration of mercury in chlorinated sodium carbonate plants and their vicinity].

The mercury control in the chloroalkali plants is a "routine method". The air is above all sampled in the chloroalkali electrolysis rooms and in the rooms under them. Already in a previous paper we had pointed out a method for the sampling and determination of the metallic mercury in these work rooms. Atmospheric samples are passed through a small glass tube containing fine spongy particles of metallic gold. As far as particle mercury sampling and analysis are concerned, environmental air is filtered by micropore filters placed on the top of the small tube filled with the gold sponge (on the same sampling line). The present work has been made with the purpose of verifying the percentage of metallic and particle mercury of the chloroalkali plants and nearby the industrial perimeter of these plants. The results have been obtained from data of two plants with different capacity, different topographic location and different microclimatic conditions. It has been noticed that the air concentration of mercury in the surrounds of the plants is higher than the basal values in incontaminated areas and the ratio between metallic mercury and particle mercury in the surroundings of chloroalkali plants is casual. The obtained data have been explained at the light of the microclimatic observations and exactly: speed and direction of winds, temperature, humidity and rainy precipitations.

Air Pollutants↗
PubMed1978

An ultrasonic analysis of the comparative efficiency of various cardiotomy reservoirs and micropore blood filters.

The ability of 12 commercially available cardiotomy reservoirs to remove bubbles from aspirated blood was investigated by means of a simulated cardiopulmonary bypass circuit and an ultrasonic microbubble detector. Performance varied considerably. The number of gaseous microemboli remaining after passage of blood through the reservoir was reduced by (a) holding the blood in the reservoir, (b) reducing the volume of air mixed with the aspirated blood, and (c) using a reservoir that did not induce turbulence and that contained integral micropore filtration material. Further micropore filtration of the blood after passage through the cardiotomy reservoir was beneficial, and significantly more bubbles were extracted when the microfilter was sited below the reservoir than when it was placed in the arterial line.

Cardiopulmonary Bypass↗
PubMed1975

Defective mononuclear leukocyte chemotaxis in the Chediak-Higashi syndrome of humans, mink, and cattle.

Chemotaxis of mononuclear leukocytes from humans, mink, and cattle was evaluated in vitro using a morphologic Boyden chamber technique and a new 51-Cr-labeled mononuclear radioassay with a double micropore filter system. Significantly decreased mononuclear leukocyte chemotactic response were noted when human, mink, or cattle Chediak-Higashi cells were tested using autologous serum or endotoxin-activated autolotous serum. A similar Chediak-Higashi mononuclear leukocyte defect was noted in humans when kallikrein or dialyzable transfer factor were used as the chemotactic stimulus. Studies using smaller pore filters in the chemotactic chamber exaggerated the chemotactic defect. Serum from Chediak-Higashi subjects had normal chemotactic activity. Additional studies on the spontaneous (random) locomotion of Chediak-Higashi mononuclear leukocytes revealed normal results when a capillary tube assay system was used, but abnormal results were obtained when a Boyden chamber micropore filter assay was used, demonstrating fundamental differences in these two assays of random locomotion. It is clear from these studies that defective mononuclear leukocyte chemotaxis is another feature of the imparied host defenses in the Chediak-Higashi syndrome that may contribute to the marked susceptibility to pyogenic infections so characteristic of this dease.

Animals↗
PubMed1992

Mastoparan activates apical chloride and potassium conductances, decreases cell volume, and increases permeability of cultured epithelial cell monolayers.

Mastoparan is a tetradecapeptide. Mastoparan added to the apical surface of monolayers of Madin-Darby canine kidney (MDCK) epithelial cells, cultured on micropore filters, activated ion transport and increased the permeability of the paracellular pathway across the monolayers. In monolayers of similar MDCK cells in which the basolateral membrane was permeabilized with Staphylococcus aureus alpha toxin (Staph. alpha toxin), the effects of mastoparan on apical membrane ion conductances were dependent on the presence of guanosine triphosphate (GTP). Mastoparan and GTP increased apical membrane chloride conductance more than potassium conductance, with very little change in sodium conductance. In intact monolayers, addition of barium to the apical bath prevented mastoparan activation of ion transport and the increase in paracellular permeability. Increasing bath potassium to 130 mM also reduced ion transport and prevented the increase in paracellular permeability. We hypothesized that these observations could be linked by mastoparan activation of apical chloride and potassium conductances, with consequent decreases in cell volume and resultant increases in paracellular permeability. Addition of 270 mM mannitol to isosmotic media to decrease cell volume decreased MDCK monolayer transepithelial resistance. Addition of mastoparan to monolayers of MDCK cells grown on micropore filters decreased cell volume to the same extent as addition of 270 mM mannitol to isosmotic media. Addition of the potassium channel inhibitor, barium, prevented the decrease in cell volume in response to mastoparan. Mastoparan activates apical membrane chloride and potassium conductances in MDCK cells. The loss of these ions from the cells decreases cell volume, and the decrease in cell volume increases the permeability of the paracellular pathway.

Animals↗
PubMed1978

Concentration-time profile of phenytoin after admixture with small volumes of intravenous fluids.

A study was designed to determine if admixtures with small volumes of four intravenous fluids (0.45% sodium chloride, 0.9% sodium chloride, 5% dextrose in water and lactated Ringer's) maintain their phenytoin concentrations over a suitable period of time to allow intravenous infusion of the drug. Three phenytoin concentrations (4.6 mg/ml, 9.2 mg/ml and 18.4 mg/ml) were prepared by adding a sufficient volume of an i.v. fluid to the appropriate volume (10.0, 20.0 and 40.0 ml) of phenytoin sodium injection (46 mg of phenytoin acid/ml) to produce a total volume of 100 ml. Each admixture was visually inspected for crystallization, the pH of each solution was determined, and the solutions were filtered through a 0.22-micrometer micropore filter. Unfiltered and filtered aliquots of all solutions were collected at 0, 0.25, 0.5, 1, 4, 8 and 24 hours following admixture. Phenytoin concentrations did not decline systematically during this period nor was there a significant difference (p greater than 0.05) between unfiltered and filtered aliquots in any of the solutions studied, except for the 9.2 mg/ml concentration of 5% dextrose in water. The phenytoin concentrations in the 5% dextrose in water and lactated Ringer's solutions showed the greatest variability over the 24-hour period. The pH for all solutions ranged from 10.15 to 11.50. One-half normal saline and normal saline in small volumes appear to be suitable vehicles for intravenous infusion of phenytoin.

Chromatography, Gas↗
PubMed1979

Effect of micropore filtration on pulmonary function after massive transfusion.

1. This study demonstrates a positive correlation between the number and size of infused microaggregates and the subsequent abnormality in pulmonary function as measured by oxygenation and dead space. 2. No such correlation between the severity of injury and the altered pulmonary function or transfusion volume was demonstrated. 3. We were unable to demonstrate an advantage to the use of a 40 mu micropore filter in preventing the adult respiratory distress syndrome (ARDS) or in improving pulmonary function in our patients. 4. One explanation for the failure to demonstrate such an advantage is the low efficiency of the filter used.

Adolescent↗
PubMed1979

Filtration characteristics of the polyester fiber micropore blood transfusion filter.

The filtration characteristics of a new polyester fiber (Fenwal II) micropore blood transfusion filter were investigated. Filtration of stored human whole blood and packed cells resulted in return of screen filtration pressure (SFP) of the blood to normal. Increased filter weights verified removal of large amounts of debris and microaggregates from the blood. Filtration of large quantities of blood accomplished at very high flow rates did not adversely affect the composition of the filtered blood. We conclude that the polyester fiber (Fenwal II) micropore blood transfusion filter is effective in removing microaggregates from stored whole blood and packed cells. It has a high volume capacity, allows rapid flow, and is reliable during pressure transfusion.

Blood Banks↗
PubMedDate not supplied

Cytology of cerebrospinal fluid: technical and diagnosis considerations.

The usefulness of cerebrospinal fluid cytology in the diagnosis of malignancy has been enhanced in recent years by the development of new techniques for increasing cellular yield. Micropore filters and a specially adapted cytocentrifuge have been used for this purpose with a resulting increase in cell concentration and in diagnostic accuracy. Cerbrospinal fluid examination has been found to be of particular value in the diagnosis of metastatic carcinoma, lymphomatous and leukemic involvement of the meninges and certain primary central nervous system tumors. Cytologic criteria for the differential diagnosis of the principal types of tumors encountered in cerebrospinal fluid are discussed.

Astrocytoma↗
PubMed1976

Elaboration of toxic oxygen by-products by neutrophils in a model of immune complex disease.

Contact between human neutrophils and aggregated immunoglobulin G bound to micropore filters has been studied as a model of the pathogenesis of tissue damage in immune complex disease. Contact with this surface, as well as with plain filters and polystyrene petri dishes, induced neutrophils to elaborate superoxide anion and hydrogen peroxide and to generate chemiluminescence, which has been attributed to singlet oxygen. Pretreatment of the cells with cytochalasin B decreased these activities but increased release of lysosomal beta-glucuronidase, suggesting that degranulation and the burst of oxygen metabolism that characterizes phagocytes are independently regulated functions. Toxic oxygen metabolites released from neutrophils are highly reactive and could mediate tissue injury at sites of inflammation.

Anions↗
PubMed1977

Polyurethane foam (Bentley) micropore blood transfusion filter: filtration characteristics.

Stored human blood of varying age was passed through polyurethane foam (Bentley) micropore blood transfusion filters. Passage through these filters resulted in decreased screen filtration pressure (SFP) of the blood and increased filter weights. Numerous microaggregates were removed and SFP returned to normal after filtration. Occlusion of the filter occurred after passage of only 2 units of whole blood. On the basis of this research, we conclude that polyurethane foam (Bentley) micropore blood transfusion filters are effective in removal of microaggregates from stored human blood. Because the filtering capacity is not great, it is recommended that when these filters are used during transfusion a new filter be used for each unit of blood administered.

Blood Preservation↗