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PubMed1981

Proteolysis and recycling of Mycobacterium tuberculosis culture filtrate tuberculoproteins.

The culture filtrate of Mycobacterium tuberculosis H37Ra has proteolytic enzyme activity which can hydrolyse extracellular tuberculoproteins. Some of the released products are transported into the cells and are incorporated into cell protein, and finally reappear in the culture filtrate as constituents of secondary tuberculoproteins. Continued extracellular proteolysis and utilization of the resultant products could produce a cyclic source of culture filtrate tuberculoproteins.

Bacterial Proteins↗
PubMed1981

Studies of antitumor activity of the culture filtrate of Hohenbuehelia geogenius (D.C. ex Fr.) Sing (basidiomycete).

The antitumor activity of the culture filtrate of the fungus Hohenbuehelia geogenius (basidiomycete) was investigated on two rapidly growing grafted tumors: Ehrlich's ascites carcinoma and L1210 lymphoid leukemia and also on a slow growing spontaneous mammary tumor in PS strain mice. The mycelial culture filtrate inhibited the growth of these three tumors. An active substance was isolated from the mycelial culture filtrate by solid-liquid extraction and column chromatography. Its chemical structure was elucidated with ultraviolet and infrared spectra, mass spectrum, nuclear magnetic resonance, and X-ray diffraction.

Agaricales↗
PubMed1980

New approach for studying macromolecular-ligand binding. Determination of the dissociation constant for macromolecule-bound ligand by gel filtration.

A graph is presented which permits facile determination of the dissociation constant constant for a macromolecule . ligand complex from gel filtration results; it can be used without a detailed understanding of the remainder of the text. When a solution of macromolecules and radioactive ligand is subjected to gel filtrations, the amount of ligand associated with the eluted macromolecule is easily measured. This quantity is then used for obtaining the corresponding dissociation constant from the graph. Values given in the graph had been determined from an equation, which is presented in the text, by means of a program which is run on a programmable calculator (Texas Instruments SR-52). It is also demonstrated how the validity of dissociation constants so obtained can be checked independently by means of a second calculation. A modification of these procedures permits determination of the dissociation constant for those situations where there is moderate dilution of the eluted sample relative to that applied to the gel filtration column, and the graph incorporates results from such calculations. The successful application of the present approach to the determination of the dissociation constants for a tubulin . [3H]GDP complex is described. Also, the potential importance of the present approach relative to other techniques for dissociation constant determination is discussed.

Chromatography, Gel↗
PubMed1980

Toxicity of cecal filtrates from guinea pigs with penicillin-associated colitis.

Lethal enterocolitis was induced in guinea pigs by intramuscular injection of penicillin. The presence of filterable toxic substance in the cecal contents of penicillin-treated guinea pigs was demonstrated. The toxin was heat-labile and produced enterosorption activity in rabbit intestinal loops and morphologic changes in Y-1 adrenal cell cultures. The cecal filtrates were lethal for mice when injected intraperitoneally and lethal for guinea pigs when injected intraperitoneally or intracecally. Cecal filtrates from saline-treated guinea pigs were not lethal to experimental animals. Filtrates prepared from broth cultures of cecal contents from penicillin or saline-treated guinea pigs also showed the presence of a lethal toxic substance. The study demonstrated that bacteremia is minimal, nonspecific and probably a terminal event in penicillin-associated deaths in guinea pigs.

Animals↗
PubMed1995

Toxigenicity of culture filtrates of Salmonella enteritidis isolates on three mammalian cell lines.

Culture filtrates of 28 Salmonella enteritidis isolates were tested for toxicity on Vero-, CHO-, and human foreskin fibroblast (HFF) cells. Cytopathic effects on HFF cells were extensive, and were observed even with some filtrates diluted 1:256. Vero cells showed effects with filtrates diluted up to 1:16, and CHO cells gave weak or no reaction. All isolates produced iron-binding siderophores as determined by reactions on chrome-azurol-S medium.

Animals↗
PubMed1994

Enhanced filtration using flat membranes and standing vortex waves.

The performance of membrane filters is limited by concentration polarisation and membrane fouling. High shear rates reduce these effects but can damage delicate cells and proteins in biological fluids. Secondary flows to promote fluid mixing, and hence enhance filtration, can be highly effective, but usually carry the penalty of complexity. Oscillatory flow over furrowed or dimpled membrane surfaces (vortex mixing) has been shown to be very efficient in the microfiltration and oxygenation of blood, but carries the added complexity of oscillatory flow and the need to thermoform the membranes. To allow the use of asymmetric or rigid membranes, a new form of vortex mixing has been studied, in which the membranes are flat and form parallel channels. Feed flow is oscillatory and passes back-and-forth across ladder-like flow deflectors to generate standing vortex waves. Flow visualisation studies and numerical calculations of standing vortex waves (SVW) were undertaken to help optimise flow parameters and flow deflector geometry. Flat plate membrane ultrafilters were built and evaluated for different geometries of flow deflector, using solutions of bovine serum albumin (BSA) as the test fluid. Very high filtration rates were measured with BSA concentrations ranging from 1 to 24%. A SVW ultrafilter was compared with a Millipore Pellicon ultrafilter using BSA as the test fluid. Filtration flux was similar at low concentrations of BSA, but was greater by a factor of 4.5 in the SVW device at high concentrations of BSA.

Chemical Engineering↗
PubMed1994

[A pathological analysis of the causes of failure of filtration operation in 25 glaucomatous eyes].

Histopathological investigations were carried out in 25 glaucomatous eyes of 25 cases which had been enucleated because of the failure of the filtration operations. Among them, 3 cases with malignant melanoma of either choroid or anterior uvea were misdiagnosed pre-operatively, post-operative rupture of filtering blebs leading to acute suppurative endophthalmitis or chronic endophthalmitis occurred in 5 cases and fibrous proliferation or incarcerations of iris, ciliary body or lens material were found in the filtration incisions in some cases. The causes of the failure of the filtration operations in these cases were discussed.

Eye Enucleation↗
PubMedDate not supplied

Effects of postoperative mitomycin C on glaucoma filtration surgery in rabbits treated preoperatively with antiglaucoma medications.

In a rabbit model, we evaluated the effects of topically applied postoperative mitomycin C (MMC) on the success rate of glaucoma filtration surgery in animals treated preoperatively with pilocarpine hydrochloride 4% and levobunolol hydrochloride (Betagan) for 16 weeks. Full-thickness filtration surgery was performed with a single 5-minute intraoperative exposure to a sponge soaked with 0.4 mg/mL MMC of one eye in nine rabbits in one group (group A) and to both eyes in 13 rabbits in a second group (group B). In addition, one eye of each rabbit in group B received a daily drop of 0.4 mg/mL MMC for 13 days after the operation. All of the eyes were then followed for 80 days. The intraoperatively applied MMC enhanced the success rate of the filtration surgery in the group A eyes. However, the eyes that also received postoperative drops of MMC (group B) had longer periods of reduced intraocular pressure (IOP) (P [chi-squared = 5.94] < .025), fewer bleb failures (P [chi-squared = 8.09] < .005), and more complications than the eyes that received only intraoperative MMC.

Administration, Topical↗
PubMed1994

Effect of 20 days bed rest upon peripheral capillary filtration rate, venous compliance and blood flow in arms and legs.

Capillary filtration rate, venous compliance and blood flow in arms and legs were measured during bed rest by strain gauge plethysmography using a liquid metal alloy in silastic tubes. Furthermore orthostatic tolerance to lower body suction was recorded. Six young healthy males and three young healthy females participated in the 20 days bed rest study. Neither arm nor leg blood flow was changed by bed rest. Arm blood flow varied between 2.18 +/- 0.30 and 3.03 +/- 0.35 vol%.min-1 and leg blood flow between 1.42 +/- 0.12 and 1.76 +/- 0.40 vol%.min-1. The capillary filtration rate tended to decrease in the arms from 0.27 +/- 0.07 vol%.min-1 at day 0 to 0.17 +/- 0.03 vol%.min-1 at day 3 and a tendency to an increase in filtration rate in the legs from 0.16 +/- 0.06 at day 0 to 0.56 +/- 0.21 vol%.min-1 at day 3 but both of these changes had recovered from day 10 on. There was a steady state in venous compliance of the forearm between 1.31 +/- 0.20 and 1.50 +/- 1.13 vol% during the first two weeks of the bed rest period but the values tended to increase to 1.75 +/- 0.16 and 1.89 +/- 0.22 vol% at days 16 and 19, respectively, while leg venous compliance showed a transient tendency to increase at day 3 (from 0.83 +/- 0.08 at day 0 to 1.30 +/- 0.32 vol% at day 3) to attain control values from day 5. Orthostatic intolerance measured during lower body suction decreased in the present subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Glaucoma filtration surgery in nonhuman primates using taxol and etoposide in polyanhydride carriers.

PURPOSE: To determine the effect of taxol and etoposide, hydrophobic drugs with antifibrosis activity, on the outcome of filtration surgery in glaucomatous monkeys. METHODS: Elevated intraocular pressure was produced bilaterally in eight cynomolgus monkeys by laser treatment of the trabecular meshwork. Four animals subconjunctivally received a polyanhydride disk containing 1 mg etoposide at the time of posterior lip sclerectomy in one eye; the other eye received an identical disk without drug. Similarly, four animals received a disk containing 50 micrograms of taxol in one eye and a blank disk in the other. RESULTS: Eyes treated with taxol had lower intraocular pressures than control eyes from 20 days after surgery until death. Eyes with satisfactory filtration bleb appearance and patent fistulae on histologic examination had lower intraocular pressures. The intraocular pressure was lower and the duration of success longer in the etoposide-treated eyes (mean, 16 days) compared to that of the fellow eyes (mean, 10 days), but the difference was not statistically significant. CONCLUSIONS: Use of polyanhydride disks containing taxol, but not etoposide, had a marked beneficial effect on intraocular pressure and bleb appearance after experimental filtration surgery in monkeys. The difference between the two agents may result from the greater antiproliferative potency of taxol and its greater duration of release from the polymer.

Animals↗
PubMed1993

[The dynamics of blood composition changes in leukocyte filtration during cardiopulmonary bypass. Preliminary results].

Activation of leukocytes (especially neutrophils) during cardiopulmonary bypass (CPB) causes a reperfusion injury through the release of oxygen free radicals and formation of microvascular occlusions. Leukocyte filtration during CPB could solve these drawbacks. We investigated the selectivity of leukocyte filtration by fifteen patients undergoing coronary artery bypass surgery. Leukocyte depleted patients (n = 8) had a leukocyte filter incorporated in the bypass circuit. We evaluated the number of lymphocytes, neutrophils and platelets as well as hematocrit values at following time points: a) before CPB, b) 15 min after the start of CPB, c) before the administration of protamin and d) 3 hours after the CPB. No statistically significant changes of hematocrit values, lymphocyte or platelet counts between control and leukocyte depleted group of patients were observed. However, the use of leukocyte filter caused significant decrease in number of circulating neutrophils at 15 min after begin of CPB (1.20 +/- 0.17 x 10(9)/l for leukocyte depleted patients and 1.90 +/- 0.42 x 10(9)/l for control group of patients, p < 0.05). Our temporary results indicate the selectivity of leukocyte filtration during the cardiopulmonary bypass.

Adult↗
PubMed1993

Intraoperative 5-fluorouracil for filtration surgery in the rabbit.

PURPOSE: Postoperative subconjunctival injections of 5-fluorouracil (5-FU) improve the success rate of filtration surgery, but there is still a 20% or greater failure rate at 1 year in pseudophakic and repeat trabeculectomy cases. The injections are inconvenient to give and may produce corneal epithelial toxicity and other side effects. An alternative method for administration of 5-FU is investigated. METHODS: A masked, randomized, prospective study was undertaken to compare bleb survival and complications in a rabbit model, after either a single intraoperative exposure to 5-FU (50 mg/ml concentration for 5 minutes) or five postoperative injections of 5-FU (5 mg injection on postoperative days 1, 3, 5, 7, and 9), or a combination of both, with controls that received only a 5-minute exposure to distilled water, intraoperatively. RESULTS: For the control eyes, all blebs were "flat" to masked grading, and intraocular pressure returned to preoperative levels by postoperative day 11. In the group receiving postoperative injections of 5-FU only, blebs were flat and the pressure normalized by postoperative day 14. Rabbits receiving intraoperative 5-FU only, or combined intraoperative and postoperative 5-FU, had consistently higher blebs than the former two groups, and some blebs survived until postoperative day 25. The mean intraocular pressure remained depressed in these groups until postoperative day 21 (P < 0.05 for days 5 through 18). A combination of intraoperative and postoperative 5-FU produced significantly higher blebs than intraoperative 5-FU alone on days 7 to 14. CONCLUSIONS: Intraoperative application of high-dose 5-FU to the filtration site either as a single 5-minute treatment, or in conjunction with postoperative injections of 5-FU greatly prolongs bleb function after filtration surgery in the rabbit.

Animals↗
PubMedDate not supplied

A subcutaneous capillary filtrate collector for measurement of blood chemistries.

The capillary filtrate collector (CFC) contains 30,000 molecular weight cut-off, hollow fiber ultrafiltration membranes that are placed below the skin. A transcutaneous tube leads to an evacuated glass tube that provides a vacuum to pull ultrafiltrate at 40-60 microliters/hr from blood, through the fibers, and past a sampling port to the glass tube. Long-term (1-6 months) animal and clinical studies have shown that the ultrafiltrate concentration of chemicals such as glucose and a variety of drugs is exactly the same as that of the blood plasma water when the ultrafiltrate is created. In this study, the device was placed in six home monitored diabetics and four in-center hemodialysis diabetic patients. Over the following month, blood glucose concentrations were compared to CFC glucose concentrations. In spite of difficulties in diluting and assaying small samples of filtrate, there was a good correlation between blood and CFC glucose levels. A flow-through enzymatic glucose sensor has been tested and shown to accurately measure glucose in CFC filtrate. When placed in the transcutaneous tubing near the skin, this should allow a small external device to continuously monitor glucose levels in brittle or out of control diabetes with high accuracy and little risk, discomfort, or cost.

Blood Chemical Analysis↗
PubMed1993

The relationship of increased capillary filtration and bone formation.

The effect of functional activity on bone formation and interstitial fluid space in a standardized tibial defect was measured in 19 dogs with one hind limb elevated and the other weight bearing and in 15 dogs bearing weight on all four legs. The interstitial fluid space (V(isf)) of the woven bone of the weight-bearing defect was larger than that in the elevated legs at seven and 14 days. By 28 days, this difference disappeared. In a third group of six dogs, medullary canal pressure was measured in the immobilized and weight-bearing tibias. The pressures were higher in the weight-bearing tibiae at two, three, four, and five days. Because the increase in V(isf) in the weight-bearing defects coincided with the onset of woven bone formation in the defects and an increase in medullary canal pressure, an increase in venous pressure could increase capillary pressure and capillary filtration. Such an increase in filtration might cause the larger V(isf) in the weight-bearing defects and better capillary perfusion of precursor cells of the osteoblast. A hypothesis is that increased fluid flow from increased capillary filtration might produce streaming potentials, a possible signal for increased cellular activity.

Animals↗
PubMedDate not supplied

[Effect of the administration of intralipid on liquid filtration rate and pressure of the pulmonary artery in isolated lung of rabbits].

INTRODUCTION: We study the effect on Intralipid on pulmonary circulation. METHODS: A 10% infusion of Intralipid was administered at a dose of 0.5/kg in 14 isolated rabbit lungs in which constant blood flow infusion was carried out principally in zone 3. The liquid filtration rate (LFR) and the mean pressure of the pulmonary artery were measured. RESULTS: A constant increase of mean pressure of the pulmonary artery was observed following the infusion (from 12.32 +/- 3.66 cm of H2O to 39.92 +/- 07.68 cmH2O (p < 0.01) which was associated to a significant increase in the rate of liquid filtration (from 0.018 +/- 0.01 g/min to 0.198 +/- 0.04 g/min; p < 0.01). CONCLUSIONS: The administration of Intralipid produces a statistically significant increase of mean pressure of the pulmonary artery and the rate of liquid filtration. This is probably caused by vasoconstriction due to metabolic changes produced by Intralipid on pulmonary circulation.

Animals↗
PubMed1993

Wound healing modulation in glaucoma filtration surgery.

In some cases, modulation of wound healing, in association with glaucoma filtration surgery, results in lower postoperative intraocular pressures than would occur without such therapy. Treatments affecting wound healing increase the likelihood of achieving long-term filtration, especially in eyes with a poor surgical prognosis. After summarizing the wound-healing process following filtration procedures, we review the mechanism of action, the effectiveness, and the complications associated with some of the most commonly used wound healing inhibitors and then discuss new alternatives currently under investigation. Although much progress has been made, the challenge remains to develop new drugs or combinations of drugs that are less toxic and can yield more predictable results.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1995

[The change of filtration-index of erythrocyte malonyldialdehyde and superoxide dismutase in patients with pregnancy induced hypertension].

OBJECTIVE: To observe the relationship between the filtration-index of erythrocytes and concentration of erythrocytic superoxide dismutase (SOD), plasma malonyldialdehyde (MDA) in cases of pregnancy induced hypertension (PIH). METHODS: We have measured the level of MDA and filtration-index, SOD content of erythrocytes in maternal and cord blood of 31 cases with PIH (group A) and 25 cases of normal pregnancy (group B) using TBA method, nucleopore membraned cell deformability meter and pyrogallol self-oxidizing method. RESULTS: The mean filtration-index level and erythrocytic SOD were significantly higher in group A than those of group B (P < 0.01 and P < 0.05). The mean content of plasmatic MDA in group A increased markedly (P < 0.01) compared to that of group B. There was no difference of these parameters in cord blood between group A and group B. CONCLUSION: The decrease of red cell deformability due to the increase of plasma MDA level may be the underlying mechanism of PIH.

Adult↗
PubMed1996

Use of oversized bandage soft contact lenses in the management of early hypotony following filtration surgery.

BACKGROUND AND OBJECTIVE: Initial overdrainage following filtration surgery can be frustrating to manage. The authors reviewed the records of 10 patients with early postoperative hypotony following filtration surgery who were treated with application of an oversized 17.0-mm bandage soft contact lens (BSCL). PATIENTS AND METHODS: Nine eyes had undergone trabeculectomy with either mitomycin-C or 5-fluorouracil intraoperative application, and one eye had undergone tenonectomy 4 years following trabeculectomy. On postoperative day 1, seven eyes were hypotonous, and three other eyes became hypotonous following suture removal or lysis. An oversized 17.0-mm BSCL was placed immediately following the diagnosis of hypotony on all eyes except one, which had the BSCL applied after 24 hours of observation. RESULTS: In 9 of 10 cases intraocular pressure rose 5 to 12 mm Hg following placement of the BSCL. During a 6- to 18-months follow-up, all successfully treated eyes had final intraocular pressures of 5 to 11 mm Hg, with extensive low to moderate height blebs. CONCLUSION: Oversized BSCLs can be a useful tool in the management of early hypotony following filtration surgery.

Aged↗