Foam Sponge Research Articles

Analyses of T-cell differentiation from hemopoietic stem cells in the G0 phase by an in vitro method.

Using differential radiation sensitivity of components of mouse embryonal thymus, an in vitro method for studying T-cell differentiation from hemopoietic stem cells (HSCs) in the G0 phase was established. Intrathymic T-cell precursors present in embryonal thymus were found to be quite radioresistant (up to 20 Gy), and consequently 25-Gy-irradiated embryonal thymic lobes were used. Thymic lobes (25-Gy irradiated) taken from mouse fetuses (gestation day 15) were placed in Millipore-HA culture plates supported on squares of gelatin foam sponge in 24-well culture plates in which neonatal thymus stromal cells were cultured. HSCs (10(5) cells per well) in the G0 phase were added to these thymic lobes and cocultured at 37 degrees C in a 5% CO2/95% air incubator. Half the culture medium was changed every week. After 3 weeks, a large number of colonies had formed. Immunohistochemical studies and fluorescence-activated cell sorter analyses revealed that the colonizing cells regularly develop and exhibit surface markers characteristic of T cells (Thy-1, IL-2R, L3T4, Lyt-2, etc.). In situ hybridization analyses revealed that mRNA expression for T-cell receptor (TCR) beta chains occurred within colonizing cells. Using a monoclonal antibody (F23.1), expression of TCR beta-chain variable domain (V beta 8) on the surface of these developing T cells was demonstrated. These cells responded to interleukin 2 and/or anti-CD3 monoclonal antibody, indicating functional T cells. This method will be useful in studying T-cell differentiation pathways from pluripotent HSCs and in clarifying the mechanisms involved in negative and positive selection of T cells within the thymus.

The extraction of uranium from acidic solutions by Adogen impregnated open cell polyurethane foam sponge

Open cell polyurethane foam coated with long chain tertiary amines (Adogen) has been shown to be an effective extractant for uranium in acidic solutions (3>pH>1). With dodecyl alcohol present uranium extraction at pH<1 is effective. The coated foam allowed column flow extraction at high flow rates but capacity studies indicated that only a fraction (about 1/3 to 1/2) of the amine was available for the complexation of the uranium. Interference of some common metal cations indicated that only Co(II) showed a significant adverse effect on the uranium extraction.

Suppression of reverberation artifact by subtraction imaging

Reverberations in ultrasound pulse-echo signals are the result of parallel specular reflectors that are perpendicular to the incident sound beam. The multiple reflections within the space between the reflectors cause a decaying pulse train of echoes to be superimposed on the returned echoes due to other structures. In a medical ultrasound B-scan, these reverberant signals obscure detail in the underlying tissue. One method to suppress these reverberation artifacts may be to subtract the images obtained at two different frequencies. This approach was tested in a water bath on a phantom of two parallel thin plastic plates in front of a foam sponge. A 5- and a 7.5-MHz transducer with similar beam profiles in the region of interest were used to create the B-mode images. The results showed that subtraction imaging resulted in a significant decrease in the reverberation artifact. Application of this method to the phantom without the sponge indicate a 7- to 13-dB decrease in the reverberant signal level.

Extraction of uranyl nitrate from aqueous nitrate solutions by open cell polyurethane foam sponge (OCPUFS)

The extraction of uranyl nitrate into open cell polyurethane foam sponge (OCPUFS) from aqueous solution, in the presence of salting agents, has been examined. The extraction efficiency was observed to depend on the concentration of uranyl and nitrate ions. The charge of the cation was also found to influence the distribution ratio. The effect of the change in temperature and pH was also studied. The results are interpreted in terms of OCPUFS acting as a viscous organic ether of moderate dielectric constant.

The 'Altered States' Foreign Body

Sir.—Young children continue to explore their environment by placing representative samples of it in their mouths. The nature of the ingested foreign body often reflects society's current technology, such as ballpoint pen clips and aluminum pop tops from beverage cans. We report a new state-of-the-art foreign body—a spongelike miniature animal within a capsule that undergoes a dramatic transformation of size and shape when placed in a liquid medium, be it bath water, as intended by the manufacturer, or gastric juice, as chosen by the patient described in this report. Patient Report.—A 2-year-old male child was suspected of swallowing an encapsulated foam sponge toy while bathing. The child showed no abnormal symptoms or signs on physical examination despite a careful search for upper airway obstruction, dysphagia, or abdominal pain. Despite the normal clinical examination, the parents insisted on further study; thus, a plain abdominal roentgenogram and an upper gastrointestinal

Foam Sponge For Cell Block Preparations in Paraffin Sections

Foam Sponge For Cell Block Preparations in Paraffin Sections

Nonprescription Contraceptives: Increasing in Popularity

The nonprescription forms of birth control now receive much attention due to the ongoing controversy about the prescription contraceptive methods. Condoms, 1 of these nonprescription methods, are the most effective nonprescription contraceptives available and among the most widely used. They are simple to use, inexpensive, and not associated with any major adverse effects. Condoms are unique in that they are a reliable contraceptive for males. It is estimated that 1 of 3 people who use contraception worldwide will rely on a male method. In the US this figure is somewhat lower, 18%. In other countries, such as Japan, condoms are the chief contraceptive method. If properly used, the failure rate for condoms is quite low; the lowest observed failure rate is 2%. In contrast, with typical users, the failure rate approaches 10%. The industry has taken several quality control measures to produce a safe and reliable condom. The principal material tested is usually either of the 2 ingredients used to make them, latex or collagenous tissue taken from the lamb cecum. Condoms definitely can protect against sexually transmitted diseases, simply because they prevent the infecting organisms from being transferred across the condom wall. The contraceptive efficacy of the condom is greatly enhanced when a spermicide is used at the same time. In terms of effectiveness, of 100 users that start the year using foams, creams, jellies, or vaginal suppositories containing nonoxynol 9 and used them consistently, the lowest observed rate of failure has been 3-5%. In actual use, the pregnancy rate is probably closer to 18%. Few side effects have been reported with spermicides. The most common of these is a burning sensation. The foaming suppository has been widely promoted as an effective vaginal contraceptive. It does not really offer any advantage over any of the other dosage forms except for convenience. It is the combination of foam and condom that pharmacists need to pay particular attention to because it is these 2 nonprescription methods that, used concurrently and correctly, can rival the efficacy of oral contraceptives. 1 of the newest dosage forms for a vaginal spermicide is a disposable polyurethane foam sponge which is impregnated with nonoxynol 9, but vaginal irritation has been reported frequently as an adverse effect.

High rate anaerobic digestion of piggery manure with polyurethane sponges as support material

The use of polyurethane foam sponges to colonize methanogenic associations for the digestion of piggery manure has been investigated. Fermentors containing polyurethane pads as colonization matrix reached a biogas production rate of ca. 2.0 litres per litre reactor per day (30–33°C), hydraulic retention time 7.5 daysl and a biogas yield of 16 litres per litre piggery manure (7–9% TS). Corresponding control fermentors containing no pads reached a gas production rate of 1.3 litres per litre reactor per day and only about 10 litres biogas per litre piggery manure.

Extraction of tin by the use of polyurethane foam

Three types of polyurethane foam were tested for the extraction of tin by static and flow systems. The amount of tin extracted varied with the type of foam, acid strength, and chloride and metal-ion concentrations. Quantitative extraction and recovery could be achieved. Open-cell polyurethane foam sponge is thought to act as a “solid solvent-extractant” for tin from aqueous solution. Distribution coefficients up to 5.6 × 10 3 were obtained and the capacity of the foam was up to 8% tin by weight.

Rat C-6 glioma cells maintained in an organ culture system: a study of kinetic parameters.

Rat C-6 glioma cells were grown on a sponge foam matrix in an organ culture system and the cell cycle parameters, including the growth fraction (GF), were assessed after autoradiography. The zones of growth consisted of a compact upper layer (UL) at the gaseous interface, a central necrotic layer and a deeper lower layer (LL) which invaded the matrix. The fraction of continuously labeled mitoses (FCLM) was similar in both the UL and LL cells. The derivatives of the FCLM curves obtained in three experiments gave an average modal TG2 of 5 hr. A mathematical model relating GF, TG2, TC and labeling index as a function of time, LI(t), was devised for cells in a steady state exposed continuously to tritiated thymidine and was applied to data obtained from UL cells. A mean GF of 9% (range: 8-10%) and a mean cell cycle time (TC') of 27 hr (range: 13-47 hr) were obtained. The mean TS was calculated to be 11 hr (range: 8-16 hr) by the method of grain counts per mitotic figure or grain index (GI). Knowledge of TS permitted alternative calculation of the cell cycle time from the equation Ts/TC = LI(0)/GF:this gave a mean cell cycle time (TC") of 29 hr (range: 20-45hr). Except for the GF, the cell kinetics were comparable to those of the same cell line grown in monolayer culture. The GF in the in vitro system described is in the lower range reported in some human malignant gliomas in vivo.

Control of postlaminectomy scar formation: an experimental and clinical study.

Scar formation after laminectomy was evaluated in dogs treated with hemostatic agents, antiinflammatory drugs, or mechanical barriers. Microfibrillar collagen was found to be superior to gelatin foam. The antiinflammatory drugs delayed healing and frequently resulted in abscess formation, and eventually scar filled the defect. The fat grafts formed a viable mechanical barrier. Gelatin foam sponge was compared with microfibrillar collagen for hemostasis with free fat grafts in a clinical series of 50 patients. The latter technique was clearly superior.

GFA expression in aggregation cultures of rat C6 glioma.

Few C6 glioma cells synthesize the astroglia-specific GFA protein in monolayer culture. A uniform population of GFA-positive cells was obtained by aggregation C6 cells in suspension culture, as previously reported for C6 glioma maintained on sponge foam matrices. These results strongly suggest that cell-to-cell interactions promote GFA expression.

The solvent extraction of Fe(III) from acidic chloride solutions by open cell polyurethane foam sponge (OCPUFS)

The extraction of Fe(III) by open cell polyurethane foam sponge was studied as a function of acid, chloride, and iron concentration in the aqueous phase. The results indicate a mixed extraction of FeCl3 and HFeCl4. The results also show a dependence of the metal distribution coefficient on [Fe(III)]aq and indicate a dissociation (in the foam) of the extracted HFeCl4 species. The solid polyurethane is equated to a liquid extractant of a moderate dielectric constant.

Transport of metal complex chlorides through plastic film membrane

THE acid–metal–chloro complexes of gallium and iron have been shown to be transported through polyurethane membranes by virtue of an acid or chloride gradient. Vofsi and co-workers1–3 have reported on transport of uranium using complexing plasticisers in thin plastic films. More recently, the transport of sodium across a liquid membrane was described4. Recent work5 has demonstrated that open cell polyurethane foam sponge with surface areas of less than 0.1 m2 g−1 can dissolve gallium or iron as the HMC14 complex to as much as 10% of the foam by weight. In this note, we investigate the transport of metal complexes, such as HMX4 of gallium and iron, across polyurethane plastic films. We believe that the acid-chloro complex could dissolve in the film and so pass through such membranes.

Gap junctions between astrocytes during growth and differentiation in organ culture systems.

Fetal rat neocortex maintained in organ culture systems with the use of sponge foam matrices and millipore filter platforms undergoes growth and cytodifferentiation along classical neuronal and glial lines up to 36 days in vitro (DIV). Astrocytic differentiation is characterized by accumulation of 80-90 A glial filaments in the cell bodies and processes of astrocytes. Gap or nexus junctions closely resembling those formed in mammalian brain in situ are identified by 15 DIV. By 36 DIV, interastrocytic gap junctions are numerous and frequently join extensive lengths of adjacent glial plasma membranes. The results suggest that these organ culture systems may provide a favorable environment for the study of cellular structure and function of coupled neuroglia.

IN VITRO CHARACTERISTICS OF A FOURTH VENTRICLE EPENDYMOMA MAINTAINED IN ORGAN CULTURE SYSTEMS: LIGHT AND ELECTRON MICROSCOPY OBSERVATIONS

Explants of a well‐differentiated fourth ventricle ependymoma were grown on collagen‐coated coverslips and in organ culture systems using gelatin sponge foam matrices and Millipore filter platforms. Viable explants were maintained on Millipore filter platforms up to 44 days and on sponge foam matrices up to 86 days. The structure of ependymal rosettes was well maintained throughout the period of study. By electron microscopy, additional features of differentiation were seen after 3 weeks, consisting of an increase in size and complexity of microrosettes, to which large numbers of cellular apical profiles contributed. Cilia with variable internal configurations were present. After 4 weeks there was frequent ependymal differentiation along the surface of the explants at their interface with the supporting matrix. Increased gliofibrillogenesis and glycogen rosettes were also evident after 3 weeks in culture. The explants were intensely positive when tested by immunofluorescence for the antigen of the glial fibrillary acidic protein. After 3 weeks in vitro, dense bands of basement membrane material forming complex intercellular finger‐like projections became prominent.

Open-Cell Polyurethane Foam Sponge as a “Solvent Extractor” for Gallium and Iron

Abstract Open-cell polyurethane foam has been shown to be effective in separating gallium and iron from aluminum in acid chloride solutions. Evidence is presented which indicates that the solid organic polymer acts as a “solvent extractor” for complex acid chlorides of gallium and iron.

Gap junctions between human meningioma cells maintained in organ culture

Intercellular junctions were commonly observed in a human syncitial meningioma maintained in organ culture for up to 44 days in vitro (DIV) using gelatin sponge foam matrices. The junctions were identified as one of three types: desmosomes; tight junctions; or gap junctions. Of the three types, gap junctions were frequently encountered and showed preservation of their characteristic ladder-like substructure. The results suggest that organ culture provides an environment that may facilitate correlation of the structure and function of gap junctions between coupled human meningioma cells.

Silicone foam sponge for pilonidal sinus: a new technique for dressing open granulating wounds.

A silicone foam sponge has been used to replace the daily packing of deep granulating wounds with moist sterile gauze. In the treatment of pilonidal sinus use of the sponge demands less nursing time and is more comfortable for the patient than the excision and open granulation technique. Patients can usually return to work soon after operation. The method has many applications in surgery, and widespread application of the technique to the management of granulating wounds could result in considerable savings to the NHS in money and skilled nursing time.

Cerebellar capillary hemangioblastoma: Its histogenesis studied by organ culture and electron microscopy

A capillary hemangioblastoma from the vermis of a 21-year-old man with von Hippel-Lindau's disease was successfully maintained in organ culture systems on Millipore filter platforms and gelatin sponge foam matrices up to 48 days. Three cell types--endothelial cells, pericytes, and stromal cells--identified by their fine structural features and their architectural relationships to vascular lumens and to the extracellular space were recognized in the original tumor. By light microscopy the explants showed, in the late stages, increased lipid droplets in the stromal cells and perivascular hyaline thickening. By electron microscopy, endothelial cells, pericytes, and stromal cells remained distinguishable as cell types. However, the stromal cells demonstrated, in addition to an increase of their normal complement of microfilaments and lipid droplets, features that were more characteristic of the two other cell types, i.e. micropinocytotic vesicles and the formation of zonula occludens junctions and hemidesmosomes. Basement membranes also became more apparent around the stromal cells. With increasing time in vitro, there was a striking increase in mature collagen fibers in the extracellular space. The roles of the different cell types in capillary hemangioblastoma and the histogenesis of the stromal cells are discussed in light of these observations. It is concluded that the capillary hemangioblastoma consists of multiple cell lines--endothelial cells, pericytes, stromal cells and, occasionally, hematopoietic cells--all of which are neoplastic and replicate in parallel with one another. Stromal cells may be regarded as an aberrant monopotential cell type which shares with the endothelial cell and pericyte a common mesenchymal, presumably angiogenic, ancestry, and may, on occasion, display morphological features, such as increased basement membrane formation and the formation of zonula occludens junctions, which recall its angiogenic lineage. However, interconvertibility between endothelial cells and stromal cells does not appear to occur in vivo or in vitro.