Hollow Fiber Devices Research Articles

A Hollow Fiber Device for Separating Water Vapor from Organic Vapors

A Hollow Fiber Device for Separating Water Vapor from Organic Vapors

An improved culture system for secondary palatal elevation.

An organ culture system devised for studying the development of the secondary palate was modified so that it retained high partial pressures of oxygen and supported total anterior and posterior palatal elevation. The cultured tissues appeared healthy as judged by histological examination. Medium was continuously recirculated through the culture system in which Day 13 embryonic mouse heads, with the brain and tongue removed, were totally submerged and suspended. The medium was constantly gassed via hollow fiber devices. A motor-driven stirrer, run at a low rate, agitated the medium so that the boundary layer surrounding the tissue was dispersed. Embryonic mouse heads were cultured in each of four media: Eagle's basal medium, Ham's F-12 medium, Fitton-Jackson's modified BGJb medium, and Waymouth's MB 752/1 medium. Elevation of the palate in both anterior and posterior regions with excellent tissue viability was achieved in all heads grown in BGJb medium.

Concentration and partial purification of lipase fromPseudomonas fluorescens

During ultrafiltration in a hollow fiber device 105 liters of lipase frort Pseudomonas fluorescens was concentrated to 4 liters with a yield of 56% of total initial activity. The concentrated lipase solution was lyophilized and purified on a DEAE-cellulose anion exchanger column. The partly purified lipase was found to probably contain carbohydrates.

Local tetracycline delivery using hollow fiber devices in periodontal therapy

Abstract. The present investigation was performed to assess the effect of tetracycline, locally administered via hollow fiber devices, on the microflora of periodontal pockets in humans and on various clinical parameters describing periodontitis. Five patients with advanced periodontal disease were used in the study. Each patient had at least four pairs of contralateral teeth where approximally located pockets could be probed to 6 mm or more. The amount of supragingival plaque present on the tooth surface adjacent to the eight diseased sites was determined as well as the degree of gingival inflammation. Probing depths were recorded with a graduated probe. The clinical measurements were repeated 7, 14, 28, and 37 days following the start of treatment. From the eight pockets bacterial samples were collected from deep subgingival sites. The bacteria were examined in a dark‐field microscope and categorized into the following groups: cocci and non‐motile rods, filaments and fusiforms, motile and curved rods and spirochetes. The percentage distribution of the various forms was calculated. Following the initial examination the patients were given detailed instruction in proper oral hygiene techniques. Three of the diseased sites were treated by scaling and three by tetracycline application using the hollow fiber device. One pair of sites was used as untreated controls. On day 28 the three initially mechanically debrided sites were scaled anew and active fiber material inserted in the three contralateral sites.The experiments showed that it is possible by the use of tetracycline‐filled hollow fiber devices to markedly change the composition of the subgingival flora of initially diseased periodontal sites. Locally delivered tetracycline proved effective in reducing or eliminating clinical symptoms of periodontal pathology.

Isolation of a hibernation inducing trigger(s) from the plasma of hibernating woodchucks.

Plasma from hibernating woodchucks was desalted utilizing a hollow fiber device having a M. W. cut-off of 5,000. This preparation was fractionated by isoelectric focusing (IEF) in a pH gradient extending from 3.5 to 10.0 resulting in protein components having isoelectric points (pIs) of 4.5, 5.2, 5.5, 6.3, and 7.0. Fraction I (comprised of proteins having pIs of 4.5 and 5.2) induced hibernation within 2 to 6 days in 8 out of 10 summer-active ground squirrels. Fraction II (pI 5.5) and Fraction III (pI 6.3 and 7.0) failed to induce any summer hibernation in 10 animal test groups at identical sample concentrations. Polyacrylamide gel electrophoresis of Fraction I indicated that albumin was a major constituent of this still heterogeneous preparation. Thus, in order to more clearly define the plasma locus of this hibernation inducing trigger(s) (HIT) molecule, whole plasma and/or Fraction I was fractionated by 3 distinct resolving techniques. These included sub-fractionation of Fraction I by isoelectric focusing utilizing a narrower pH gradient extending from 3.5 to 6.0, isotachophoresis of whole plasma and affinity chromatography of Fraction I and whole plasma. A total of 40 summer-active ground squirrels were injected and assayed for HIT activity with fractionated preparations derived by the three previously cited separation techniques. A total of 18 of these summer-active ground squirrels hibernated. However, a much more impressive figure is that 16 out of 21 animals hibernated when injected with resolved hibernating plasma fractions in which albumin was the predominant plasma protein. A total of 8 control animals were injected with vehicle and none of these hibernated.

Partial Purification of Human Lymphocyte-Activating Factor (LAF) by Ultrafiltration and Electrophoretic Techniques

Lymphocyte-activating factor (LAF) has been produced by culturing human peripheral blood leukocytes in the presence of lipopolysaccharide and autologous human serum. The major LAF activity, identifiable by Sephadex chromatography (m.w. 13,000) was separated from most serum proteins in the culture medium by ultrafiltration with a hollow fiber device. Sucrose gradient isoelectric focusing of the concentrated ultrafiltrate yielded a single peak of LAF activity with an average isoelectric point of pH 6.8. Semi-preparative polyacrylamide gel electrophoresis of the isoelectric focusing sample resulted in separation of the LAF activity from detectable amounts of serum proteins. The recovered LAF activity was estimated to be purified more than 16,000-fold and is judged to be active in submicrogram amounts.

Studies on new process procedures in plasma fractionation on an industrial scale. II. Experiments in concentrating dilute albumin solutions using hollow fiber ultrafiltration.

Ultrafiltration with a hollow fiber device was studied as an alternative method to the lyophilization or thin-layer distillation techniques in the production of salt-poor, concentrated human albumin preparations for clinical use. A number of process parameters are discussed. Combination of gel filtration and ultrafiltration provides an interesting alternative to the currently used systems.

Studies on New Process Procedures in Plasma Fractionation on an Industrial Scale

Ultrafiltration with a hollow fiber device was studied as an alternative method to the lyophilization or thin-layer distillation techniques in the production of salt-poor, concentrated human albumin preparations for clinical use. A number of process parameters are discussed. Combination of gel filtration and ultrafiltration provides an interesting alternative to the currently used systems.