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PubMedDate not supplied

[The role of changes in vascular permeability, interstitial relaxation and surface tension forces in the alveoli in disordered filtration-absorption equilibrium in pulmonary edema].

Changes of fluid filtration and reabsorption in application and removal of hydrodynamic loads were studied on isolated lungs of dogs. Some models of transcapillary filtration in the lungs were studied on basis of the obtained data. According to the theoretical predictions of these models, the following factors influence the non-linearity of the filtration and reabsorption processes most essentially: interstitial relaxation in the stage of interstitial edema and the appearance of surface tension forces in the alveoli. The hypothesis of the significance of disturbed permeability of the capillary wall is confirmed to a very small measure with such an approach. The described phenomena allow the processes of fluid accumulation in pulmonary edema to be represented on a mathematical model.

Absorption↗
PubMed1988

The use of bioerodible polymers and 5-fluorouracil in glaucoma filtration surgery.

A study was performed to examine the effect of a localized and sustained delivery of 5-fluorouracil (5-FU) on the success of glaucoma filtration surgery in 18 rabbits in a prospective, randomized, double-masked and placebo-controlled fashion. A bioerodible polyanhydride composed of bis (p-carboxyphenoxy) propane and sebacic acid was used as the drug carrier. The polymer and 5-FU (20% by weight) were compressed into 3 mm diameter discs, 1 mm thick. The polymer with the 5-FU was randomized to one eye and the fellow eye received the blank polymer. The results showed that intraocular pressures (IOP) were lower in the experimental eyes during the 5th through 17th postoperative days, but eventually both experimental and control eyes returned to preoperative levels. Filtration blebs lasted longer in experimental eyes when compared to control eyes. Implant disappearance occurred after IOP elevations and bleb failure. Eventually, the filtration surgery failed in both the experimental and control rabbit eyes.

Animals↗
PubMed1978

Binding of colony stimulating factor by sterile filtration membranes.

Loss of serum-free L-cell colony stimulating factor (CSF) activity was noted when non-sterile or ethylene oxide sterilized Millipore filters were employed; autoclaved membranes showed no inactivation. The reduction in CSF did not appear to be due to release of inhibitory or inactivating substances as extensive rinsing with various solvents did not prevent loss of CSF activity. In addition, these filtrates did not inhibit the activity of standard CSF. Less pure sources of CSF, including standard serum containing L-cell CSF and human urinary concentrate, did not lose activity upon filtration. Moreover, the addition of bovine serum albumin to serum-free CSF completely prevented membrane filtration loss. The CSF loss could be prevented by treatment of the membranes with buffers contraining 0.05% polyethylene glycol (PEG). These findings show that Millipore membranes can bind significant quantities of partially purified CSF. It is important in purification studies to recognize that CSF loss can be prevented by addition of PEG to all buffer systems.

Colony-Stimulating Factors↗
PubMedDate not supplied

Couette membrane filtration with constant shear stress.

Recent developments in the field of blood component separation have revealed the usefulness of membrane filtration using couette type configurations and Taylor vortices as an efficient and effective method. The authors have analyzed in detail the physical and chemical effects on whole blood separated into protein rich plasma, and concentrated red blood cell suspensions, using this technique. The authors also have calculated and demonstrated the technical specifications required to provide laminar flow with Taylor Vortex formation throughout the device, as well as those required to retain constant shear stress on the blood components as viscosity changes. By maintaining constant shear stress below a critical level, it is possible to avoid shear induced hemolysis and to maintain maximal separation efficiency throughout the procedure. The device has further been designed to alter the filtration velocity along the membrane so that the critical filtration velocity is nowhere exceeded, i.e., concentration polarization effects are prevented.

Blood Component Removal↗
PubMed1987

Performance evaluation of cascade filtration with high flow rate recirculating plasma on the secondary filter.

Cascade filtration (CF) has been performed in 67 on-line procedures in 9 normolipidemic patients with paraproteinemic disorders. A modified dead-end technique has been employed, with high flow rate recirculating plasma on the plasma fractionation filter (QD recycled CF), and an albumin-rich, globulin-poor filtrate was reinfused into the patient. Postprocedure recoveries were 81 +/- 15% for albumin, 55 +/- 23% for IgM and 48% for cryocrit, with an increase in A/G ratio from 1.8 to 2.1. An improvement was observed also in antiatherogenic/atherogenic lipoproteins ratio, suggesting a possible use of this technique in the treatment of familial hypercholesterolemia. Plasma primary separation was obtained by centrifugation or by filtration, and no significant differences were observed on subsequent protein fractionation process. An albumin priming of the plasmafractionation circuit accounted for an additional 13% saving in postprocedure level. Different surface area secondary filters have been employed: with larger surfaces, larger volumes were processed without any increase in the waste volume and with reduced need for washouts, but with an additional loss of small molecules possibly due to entrapping onto the membrane.

Blood↗
PubMed1987

[Cascade use of plasmapheresis and plasma filtration in the treatment of rheumatoid arthritis].

The effect of incorporation of cascade plasmapheresis and plasma filtration in multimodality therapy was studied in 4 patients with rheumatoid arthritis (RA). The result was estimated as "excellent" (complete disappearance of clinical symptoms of the articular syndrome and normalization of the activity laboratory indices) in one patient; "good" (the reduction of clinicolaboratory activity) in 2 patients and "satisfactory" (the reduction of symptoms of the articular syndrome without changes of a degree of general activity of disease) in one patient. Cascade plasmapheresis and plasma filtration significantly improved clinical and many laboratory indices of RA activity and humoral immunity indices during treatment. A long period of observation is required to assess long-term results of the effect of this method. A great advantage of the method is a possibility of decreasing substitution protein solutions without negative effects with relation to the blood total protein level. The absence of a necessity of catheterization of central vessels, more complete blood separation into plasma and erythrocytes make cascade plasmapheresis and plasma filtration more preferable. Good tolerance of the procedure, fast improvement, a chance to avoid side-effects of drug therapy, a lower risk of allergic reactions to plasma substitutes as compared to those in plasmapheresis and lymphocytoplasmapheresis make the method promising for RA treatment.

Aged↗
PubMed1986

[Filtration-absorption functions of the lungs during changes in respiratory volume].

In anesthetized cats, within the range of intermittent transpulmonary pressure (from -8 to +8 mm Hg) no significant shifts of the filtration-absorption balance were revealed. At the transpulmonary pressure +14 mm Hg the capillary hydrostatic pressure increased by 30% and filtration prevailed over absorption. Similar changes could occur at +8 mm Hg in case the tone of the lung vessels was reduced with papaverin. Mechanisms of effect of the respiratory volume changes on the filtration-absorption balance in the lungs, are discussed.

Animals↗
PubMed1986

[Changes in the filtration-absorption equilibrium in the lungs in response to electrolyte hemodilution].

I. v. administration of lactasole increased the capillary filtration coefficient, precapillary resistance and the pressure in the lung artery in anesthetized cats, the capillary hydrostatic pressure and the blood flow diminishing in these conditions. I. v. administration of the Ringer solution increased the capillary filtration coefficient and postcapillary resistance; no shifts of the capillary hydrostatic pressure, precapillary resistance, blood flow or arterial pressure, were found. Possible mechanisms of effects of the hemodilution with above solutions on the filtration-absorption balance in the lungs, are discussed.

Animals↗
PubMed1986

Selective removal of pathogenetic macromolecules directly from whole blood by double filtration technique.

Double filtration plasmapheresis (DFPP) is a technique devised in an attempt to selectively remove pathogenetic macromolecules such as antibodies, immune complexes or viscosity-increasing substances directly from blood. In order to realize the differential filtration principle, two filters, one for separation of plasma and another for fractionation of plasma components, are installed in an extracorporeal circulation line. Selective separation of the plasma components is dependent on the filtration property of the two filters. Clinical experiences evidence the usefulness of this technique in regard to conservation of human blood products for supplementation.

Blood↗
PubMed1986

[Ultrastructural changes in the microcirculatory bed and filtration-reabsorption barrier of the kidney during temporary ischemia after unilateral nephrectomy].

Ultrastructure of cellular elements of the microcirculatory bed and filtration-reabsorption barrier has been studied in 150 mature white rats, in which vascular fasciculus of the left kidney has been compressed for 30 min, 1-2 h with a subsequent restoration of the blood stream in the organ undergone ischemia on the 3rd, 7th, 14th, 30th, 60th, 180th, 360th days under conditions of the preliminarily right kidney nephrectomy. On the 3rd day after ischemia of the remained kidney for 30 min, structural components of the walls of the glomerular arterioles and those of the filtration-reabsorption barrier undergo certain ultrastructural changes, that with time elapsed (7, 14 days) gradually pass away, and amount of cells with hypertrophic processes increases. Ischemia for 1 h in the remained kidney with subsequent restoration of the blood stream on the 3rd, 7th days produces in the structures mentioned more pronounced destructive changes. During subsequent compensatory hypertrophy (the 30th, 60th days) of the remained kidney after its ischemia, in the microcirculatory bed elements and in the convoluted canal epitheliocytes intracellular regenerative and hyperplastic processes develop. However, ischemia for 2 h in the remained kidney produces severe destructive-necrotic phenomena in ultrastructure of the microcirculatory bed and of the filtration-reabsorption barrier.

Animals↗
PubMed1985

Genetic transformation in Streptococcus sanguis. Effects on genetic transformation by culture filtrates of Streptococcus sanguis (serogroups H and W) and streptococcus mitis (mitior) with reference to identification.

Streptococcus sanguis (serogroups H and W) strains are frequently competent in genetic transformation. In a collection of 18 strains of S. sanguis isolated from blood cultures, 12 strains were spontaneously competent in transformation by streptomycin-resistant DNA, and three strains were induced to competence by the use of culture filtrates containing competence factor (CF). Culture filtrates from spontaneously competent S. sanguis strains only induced competence in transformation of strains of the same species. In addition to the three "constitutional" types of S. sanguis with regard to specificity of transformation previously reported (originally represented by the strain Challis, 13b and NCTC 7863), a possible fourth type, (represented by strain 21452) was found. Further studies are required to ascertain the role of these types. The "constitutional" types are characterized by the range of activity of their CF's. These specificities seem useful in identification of S. sanguis and its separation from S. mitis (mitior). Tests of spontaneously competent strains with culture filtrates from other competent strains showed variable effects on the transformation frequencies in different strains.

Bacterial Proteins↗
PubMed1969

Studies of escherichia coli in gnotobiotic pigs. VI. Effects of feeding bacteria-free filtrates of broth cultures.

Nine gnotobiotic pigs derived from one gilt were fed bacteria-free filtrates prepared from: 1) cultures of an enteropathogenic strain of Escherichia coli 09:K.:NM (Strain 340), 2) cultures of a nonenteropathogenic strain of E. coli 08.K..H16 (Strain CDC-1466-56), and 3) uninoculated culture medium. Diarrhea was observed initially two to four hours after feeding the filtrate prepared from the enteropathogenic E. coli. The duration of diarrhea was five to ten hours. No diarrhea was observed after feeding filtrate prepared from uninoculated medium or cultures of nonenteropathogenic E. coli. The pH values of the feces increased with the onset of diarrhea and decreased to normal after diarrhea stopped. No histopathological lesions were found.

Animals↗
PubMed1984

[Plasma exchange by cascade filtration. Clinical and biological study].

Nineteen double-filtration plasma exchanges were performed in 8 patients selected according to the presence or absence of disease-related and/or patient-related risk factors. The haemofiltration system consists of 2 filters with different pore sizes. The first filter, called plasma separator (Asahi plasmaflo HI-05), separates plasma from whole blood; the second filter, called plasma filter (Asahi XK-60; Kuraray Eval 2A or 4A), separates high molecular weight components from plasma. The filtrate from the second filter is returned to the patient mixed with blood cells and either a 4% albumin solution or Plasmion to replace the plasma discarded (about 0.5-0.8 I for a 1-1.5 plasma mass treated). The system (a) modulates venous pressure and transmembrane pressure in each of the two filters by means of pump velocity variations; (b) recirculates and concentrates the plasma extracted, and (c) provides information on the plasma mass extracted by the second filter. In our study, antihistaminics were always infused before each plasma exchange session, and blood pressure and electrocardiogram were monitored throughout the session. The selectivity of the second filter is relatively good for low and high molecular weight components (e.g. albumin and IgM respectively), but needs to be improved for those of intermediate molecular weight, such as IgG and immune complexes. The amounts of plasma substitute utilized are about 6 times less than with conventional methods; however, transmembrane pressure in the second filter is imperfectly controlled, and this too calls for improvement. A study is in progress to evaluate the ideal plasma mass to be extracted. Clinically, and taking into account the biological results obtained, diseases with high molecular weight mediators should benefit from the double-filtration technique, but this technique needs to be perfected for the treatment of IgG-mediated diseases.

Antigen-Antibody Complex↗
PubMedDate not supplied

[Restoration of the sensitivity of cells resistant to Coxsackie B3 virus after treatment with sensitive cell filtrate].

The study was done with J-96 cell line sensitive to Coxsackie B3 virus and the subline J-41 derived from it and resistant to this virus. In order to determine the substrates responsible for the susceptibility or resistance of these cells to Coxsackie B3 virus, homogenates and filtrates of the susceptible cells were inoculated into resistant ones and vice versa. Inoculation of the resistant cell homogenates into the susceptible cells at various intervals after virus inoculation did not inhibit virus development. Inoculation of a filtrate of the susceptible cells into resistant ones followed by long-term cultivation resulted in restoration of the susceptibility. Reversion of susceptibility to Coxsackie B3 virus was gradual and accompanied by restoration in the cells of positive Homari test to alkaline phosphatase. The positive result was obtained twice in the absence of reversion in control cells not treated with the filtrate.

Antigens, Viral↗
PubMed1984

Preparation and sterilization by filtration of Renacidin irrigation.

A method for the sterilizing filtration of Renacidin, a urologic irrigating solution, was evaluated. Renacidin irrigation was prepared and sterilized by microporous membrane filtration. A sterilizing membrane filtration apparatus was challenged by inoculating a batch of irrigation solution with Escherichia coli. The sterility of both intentionally contaminated and routinely prepared batches was evaluated. The stability of the solution was monitored by pH measurement, visual examination, maintenance of a vacuum, and absorbance spectrum of a 1:100 dilution in deionized water over a wavelength range from 400 to 200 nm. The time required to prepare three one-liter units was about two hours. No microbial growth was detected in any of the samples. The predicted minimum shelf-life at 10 degrees C was six months. Because the prepared solution contains some unreacted citric acid and bicarbonates, storage at room temperature could produce excessive pressure inside the container from carbon dioxide gas evolution. Refrigerated storage is recommended. This method for the preparation and sterilization of Renacidin irrigation is reasonably expedient, economical, and reliable.

Chemical Phenomena↗
PubMed1978

[Isolation of sarcolemma acetylcholinesterase fractions by gel-filtration through Sepharose 2B].

Gel-filtration of 0,6 M NaCl and 0,6 M NaCl--0,1% Triton X-100 extracts of freshly isolated sarcolemma through Sepharose 2B (1,5 X 72 cm) has revealed one symmetric peak of acetylcholinesterase activity containing phospholipid and cholesterol, moving faster than fibrinogen and tyreoglobulin. The acetylcholinesterase fraction is substantially separated from other extract proteins. Gel-filtration of extracts from long-store, treated by ultrasound or high concentration of detergent sarcolemma has revealed some peaks of acetylcholinesterase activity, which may be suggested to be degraded forms of the complex high molecular weight structure. All species of acetylcholinesterase are converted by treatment with trypsin to a form moving upon gel-filtration with enzyme-marker catalase. The microsome extracts contain only the form moving with catalase.

Acetylcholinesterase↗
PubMed1983

Technical and clinical aspects of cascade filtration plasma exchange (CFPE).

Cascade filtration plasma exchanges (CFPE) were realized using an hemofiltration system (HFS) coupled to 2 filters with different pore sizes. The first one (F1 = plasma-separator; Asahi plasmaflo HI-05) separates plasma from whole blood, the second one (F2 = plasma filter; Asahi XK-60, Kuraray EVAL 2A or 4A) filtrates high molecular weight (MW) components from the separated plasma. F2 filtrate returns to patient mixed with blood cells and 4% Albumin solution or Plasmion R replacing plasma discarded (about 0.5-0.8 I for 1-1.5 plasma mass (PM) treated). The HFS is able i) to modulate the different pressures (venous pressure, F1 and F2 transmembrane pressures (TMp] using pumps speed variators, ii) to recirculate and concentrate extracted plasma and iii) to know F2 treated PM. Blood pressure, pulse rate and electrocardiogram were monitored during each CFPE session. Nineteen CFPE were performed for 8 patients selected among our PE indications, this selection taking into account presence or not of risk factors linked to disease e and/or to patient. Anti-histamine drugs were always infused before CFPE session. On a biological point of view, the problem lies into F2 selectivity which is relatively good for low (as Albumin) and high (as IgM) MW molecules which are returned to patient or discarded, but should be improved for the intermediate ones (as IgG). On a technical point of view, the plasma substitute quantity is reduced about six times. But the control of F2 TMp is not perfectly and the PM to be treated has to be investigated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1981

Proof for the lack of diphtheria toxin in culture filtrates of Corynebacterium ulcerans strain ATCC 9015.

Extensive efforts to identify the diphtheria toxin in culture filtrates of C. ulcerans strain ATCC 9015 was unsuccessful. The culture filtrates did contain a component (called D-antigen) which formed a precipitin line with commercial diphtheria antitoxin. This component was purified by immunosorbent techniques using immobilized preparations of diphtheria antitoxin. It was shown, that D-antigen has a molecular weight of 84000, is not toxic for guinea-pigs, and has nothing in common with purified diphtheria toxin when tested in gel-diffusion tests. The lack of diphtheria toxin in form of its fragments in culture filtrates concentrated 20-fold was proved by the highly sensitive and specific viroimmunoassay.

Animals↗