Micropore filter methods for leukocyte chemotaxis.
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Animals↗
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Examination of a rheological profile for blood using micropore filters.
Various techniques have been used to assess the flow properties of blood and blood cells in a range of clinical situations. Filtration through microfilters offers a single technique for measuring the flow properties of all cellular components of blood in one experiment but depends on an assumed ability to recognize cells that make up <10% of leucocytes. The remaining leucocytes, labelled fast leucocytes, were previously presumed to be lymphocytes and granulocytes. This study confirmed the identities of these fast leucocytes as those of lymphocytes and granulocytes in undiluted blood. The transit time for lymphocytes (1.2 s) and granulocytes (1.6 s) is close to that recorded for fast leucocytes (1.7 s). The resistance of each type of blood cell to flow through 5 microm filters was defined in this study as the product of the concentration of that cell in blood and its transit time through a pore in the filter. The total resistance to flow of healthy blood through the filter is 4.46 x 10(7) s/ml and is attributed to plasma (2.7%), red cells (25.9%), fast leucocytes (25.3%) and slow leucocytes (46.1%). In a cohort of 21 men with peripheral arterial disease the total resistance was increased to 7.82 x 10(7) s/ml and attributed to plasma (1.5%), red cells (14.5%), fast leucocytes (21.0%) and slow leucocytes (63.00%). This analysis therefore provides a single test for assessing the flow properties of all the cellular components of blood and plasma.
Blood Viscosity↗
Humic acid interference with virus recovery by electropositive microporous filters.
The effects of humic acid on poliovirus type 1 recovery from water by Zeta Plus 60S filters were investigated. The humic acid interfered by preventing virus adsorption to the filters, and the interference increased as a function of the amount of humic acid filtered. Humic acid decreased virus adsorption when filtered before the virus, but did not elute virus which had adsorbed to the filters. The effects on virus recovery were not due to alterations in virus titer or neutralizability. The addition of AlCl3, which improved virus recovery by electronegative filters in the presence of humic acid, did not aid in overall virus recovery by the Zeta Plus filters in the presence or absence of humic acid. However, the salt and humic acid in combination improved virus adsorption and concurrently reduced virus elution efficiency. The addition of NaH2PO4 had no direct effect on virus recovery and did not alter the effect of humic acid. In an attempt to identify the components of humic acid responsible for the interference, humic materials were fractionated by size by using Sephadex gel chromatography and dialysis, and the fractions were tested for interfering activity. Interference was not associated with specific size fractions of the humic materials.
Adsorption↗
The use of micropore filters in the adminstration of intravenous fluids.
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Filtration↗
Immunofluorescent F-P ratios of some B. Subtilis conjugates for use with microporous filters.
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Animals↗
[Corpuscular contaminants in solutions used in ocular microsurgery: prevention using micropore filters].
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Drug Contamination↗
[Micropore filters for preventing venous air embolism during infusions (author's transl)].
The use of automatic pumps in intensive care medicine does not preclude the risk of accidental air embolism. The repeated introduction of small air bubbles into the infusion system in the course of additional medication may have a cumulative effect resulting in the blocking of the pulmonary capillary system. The use of 0.22 micrometer filters for eliminating air prevents this complication of infusion therapy. The efficacy of the microfilter Ultipor type FAE-020 (marketed by Pall Biomedizin GmbH) in preventing the introduction of air was tested in 50 specimens with 650 single injections and 10 slow drip infusions by means of the ultrasound Doppler technique. The filters reliably stopped the introduction of air into the circulation.
Embolism, Air↗
[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↗
[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↗
Improved method for concentration of Giardia, Cryptosporidium, and poliovirus from water.
Methods for the concentration of enteric viruses and the protozoan parasites, Giardia and Cryptosporidium, from drinking water currently require the use of two different types of filters. Electropositive or electronegative microporous filters (0.2-0.45 microm nominal porosity) are used for the collection of enteroviruses, while polypropylene spun-fiber filters (1 microm porosity) and small pleated cartridge filters are used for the collection of protozoan parasites from water. Since the filter mechanically traps the protozoa by size exclusion, a microporous filter with an appropriately small nominal porosity could possibly be used for co-collection of both protozoa and enteroviruses. This study compared the concentration efficiencies of a polypropylene fiber cartridge (DPPPY) filter and two different microporous filters (Filterite and IMDS) with poliovirus (type 1), with respect to their ability to concentrate Giardia and Cryptosporidium from water. Giardia cysts and Cryptosporidium oocysts were added to 4001 of either tap water or tertiary treated wastewater and passed through the test filter. The protozoa were eluted from the polypropylene filter by hand-washing in a detergent solution. Viruses and protozoa were eluted from the microporous filter by two consecutive back-washes with a 1.5% beef extract, 0.1% Tween 80 solution. The eluent was then centrifuged to remove the parasites and the supernatant assayed for viruses. The overall efficiency was greater for the Filterite filter (40.4% for Giardia; 36.6% for Cryptosporidium) when compared to the spun fiber filter (10.1% for Giardia; 16.0% for Cryptosporidium). The Filterite filters were easier and faster to process than the polypropylene spun fiber filters. There was no significant difference in the recovery of protozoa from 1MDS and DPPPY filters. Co-collection of viruses and protozoan parasites from water onto the same filter is possible and can reduce the time and cost of routine water monitoring.
Animals↗
RBC destruction caused by a micropore blood filter.
Two infants who received whole blood filtered through commercially available woven stainless steel micropore filters experienced a sudden onset of hemoglobinuria. The plasma hemoglobin level in one child was 200 mg/dL. To investigate whether filters might lead to RBC destruction, we experimentally quantitated filter-induced hemolysis using standard conditions. Our studies in vitro show that hemolysis decreases with increased speed to transfusion. Hemolysis is particularly extensive with blood stored more than 14 days, but measurable hemolysis occurs with blood stored for as little as one day.
Blood↗
[Does an injection filter modify the cranial spread of a sensory blockade in epidural anesthesia?].
UNLABELLED: In a prospective study we compared the spread of sensory blockade in epidural anaesthesia with and without Micropore filter. MATERIALS AND METHODS: A total of 32 patients undergoing varicose vein stripping under epidural anaesthesia were randomly assigned to two groups of 16 each. Bupivacaine 0.75% and POR 8 (0.1 IU/ml) were administered by means of a constant-velocity perfusor. In group A a Micropore filter was inserted between the perfusor syringe and the epidural catheter. In group B the epidural catheter was connected to the syringe without the filter. The puncture was performed at the L3-4 interspace with the patient in a sitting position. An epidural catheter was advanced 3 cm cephalad. Using the pin-prick method, the sensory level of the blockade was tested 5, 7, 10, 15, 20 and 30 min after injection of the local anesthetic solution. Statistical evaluation was performed with the t-test for unpaired samples. RESULTS. After 10 min the spread of analgesia was 5.75 +/- 1.26 segments in group A and 8 +/- 1.89 segments in group B; after 15 min it was 7.06 +/- 1.62 segments and 9.56 +/- 1.54 segments; after 20 min, 7.87 +/- 1.62 segments and 10.62 +/- 1.45 segments; and after 30 min 8.12 +/- 1.66 segments and 11.12 +/- 1.45 segments in group A and B, respectively. At any time sensory blockade was higher in group B (without Micropore filters) than in group A. The mean difference between the two groups amounted to 2-3 segments. The differences were significant at any time (P less than 0.001). These results show that the use of a Micropore filter in epidural anaesthesia leads to a reduced spread of sensory blockade. In our own examinations we found lowering of the pressure of the local anaesthetic solution that passes through the Micropore filter compared with the pressure of the solution injected without the filter. This seems to be the reason for the reduced spread of sensory blockade. Using these filters the onset of analgesia is delayed, and a given spread of analgesia needs a larger dose of local anaesthetic and is thus accompanied by a higher toxicity.
Adult↗
Blood flow properties and walking performance in chronic arterial occlusive disease.
Recent investigations suggest an interdependence between blood fluidity and walking performance in patients with peripheral arterial occlusive disease (PAOD). Therefore, various blood fluidity variables (erythrocyte aggregation, erythrocyte flexibility, plasma viscosity, plasma proteins) were studied in groups of healthy subjects and claudicants with severe PAOD (exhausted perfusion reserve) receiving intravenous treatment with Trental (600 mg Pentoxifylline b.i.d., 21 days). Erythrocyte flexibility (expressed by filterability through micropore filters), red cell aggregation and plasma viscosity deteriorate with progression of disease especially in Stage IIb and III Fontaine classification, with walking distance below 150 m. Trental treatment resulted in patients with advanced POAD stages in improvement of red cell filterability, red cell aggregation, decrease of plasma viscosity, increase in absolute walking distance and relief from rest pain, suggesting that such patients are accessible to conservative treatment with hemorheologically active agents.
Aged↗
[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↗
[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↗
Characterization of corneal endothelium cell cultured on microporous membrane filters.
In these experiments we characterize rabbit and bovine corneal endothelia cell cultured on microporous membrane filters (0.6cm2). Cell cultured bovine or rabbit corneal endothelial cells (subcultures 1-3) were seeded onto Millicell-HA filter inserts. Electrical resistance measured across the cultured monolayers increased steadily through 14 days of culture, reaching 34.2 +/- 0.8 ohm-cm2 (mean +/- SE) for rabbit cells and 33.1 +/- 1.1 ohm-cm2 for bovine cells. Alizarin red staining of the monolayers showed a polygonal morphology comparable to that observed in situ. Transmission electron microscopy showed well developed apical junctional complexes and flaps. Exposure of the monolayers to calcium-free medium resulted in the disruption of intercellular junctions, rounding-up of the cells and a decrease in electrical resistance (to near 0). Transmonolayer fluxes of inulin and dextran correlated well to the resistance measurements. Results of this study demonstrate that corneal endothelium, both bovine and rabbit, grown on filter inserts is comparable in morphology and ultrastructure to corneal endothelium in situ. The cells cultured in this system form functional apical junctional complexes that effect a barrier function comparable to that of the endothelium in situ.
Animals↗
Evaluation of filters for recovery of Campylobacter jejuni from water.
Campylobacter jejuni has been incriminated in several large waterborne outbreaks, but it has rarely been isolated from water itself. Better methodology is needed for the isolation of C. jejuni from water. We evaluated three types of 0.45-micron microporous filters and three different pore sizes of positively charged depth filters for their ability to recover C. jejuni from seeded, sterile tap and surface water. The microporous filters tested were Millipore HA, Gelman GN6, and Zetapor. Three pore sizes of Zeta Plus depth filters (05S, 30S, and 50S) were evaluated by using an adsorption-elution technique. The overall percent recovery in both tap and surface water by microporous filters was: Zetapor, 66%; Millipore HA, 33%; and Gelman GN6, 33%. Adsorption-elution with Zeta Plus 50S allowed 89% recovery of C. jejuni. These data suggest that both the positively charged Zetapor microporous filter and the Zeta Plus 50S depth filter are effective filters for the recovery of C. jejuni from water.
Bacteriological Techniques↗
[Determination of metals in atmospheric particulates by atomic absorption spectrometric method (AAS) with CA-CN micropore membrane filters used for sampling].
A new sampling method of atmospheric particulates using 0.22 microm pore diameter micropore membrane filters was introduced. Copper, lead, zinc cadmium, manganese, iron, nickel and chromium in atmospheric particulates were determined by atomic absorption spectrometry. This sampling method has shown several advantages: easy, complete and fast digestion; low membrane blank; increased flexibility to surrounding temperature change; high elution recovery, standard addition recovery, precision and accuracy.
Metals↗