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At least 397 records · Page 22Linked to original sources
PubMed1985

Oxytocin and vasopressin in the rat do not readily pass from the mother to the amniotic fluid in late pregnancy.

In order to see whether the mother contributes to the vasopressin or oxytocin levels of amniotic fluid, these peptides were measured under conditions (1) in which the fetus lacks vasopressin (Brattleboro strain) and (2) where high maternal oxytocin and vasopressin plasma levels were induced by means of a controlled-delivery Accurel-collodion device. No vasopressin could be demonstrated in amniotic fluid of vasopressin-deficient fetuses present in a heterozygous (i.e., vasopressin-synthetizing mother). High peptide levels on the maternal side of Wistar rats generally failed to affect the amniotic fluid levels. The increase that was occasionally seen in amniotic vasopressin was probably due to fetal release concomitant with growth retardation. Amniotic vasopressin is derived from the fetus. Since amniotic fluid oxytocin is neither derived from the mother nor from the fetal brain, other fetal sources should be considered.

Amniotic Fluid↗
PubMed1976

Effects of ethanol on the permeability of toad urinary bladder epithelium.

Ethanol (9%) decreases the potential difference across the toad bladder when present at the mucosal surface, the short-circuit current was unchanged. The electrical resistance decreased indicating a change in ion movements across the bladder. Unidirectional 22Na and 36Cl flux measurements showed an increase in the movement of Cl, but no change in Na. The vasopressin-induced increase in Na transport (natriferic response) was also unaffected by the presence of ethanol. It is suggested that ethanol may be altering the apical tight junctions and affecting an anion selective pathway. The hydro-osmotic response of the toad bladder to vasopressin was decreased by 70% in the presence of 3% ethanol. The hydro-osmotic action of cyclic adenosine monophosphate was also inhibited by ethanol, indicating an action subsequent to the endogenous formation of this nucleotide. Tritiated water fluxes (in the absence of an osmotic gradient) were reduced by 30% in the presence of 3% ethanol. The vasopressin-induced increase in diffusional water flow was similarly reduced. Osmotic water movements across glutaraldehyde and N-ethylmaleimide-"fixed" vasopressin-stimulated bladders were also decreased in the presence of ethanol. However, 3% ethanol had no effect on osmotic water transfer across artificial collodion membranes. Ethanol, therefore, probably interacts with the bladder membrane. The Ktrans (permeability coefficient) of ethanol and water is increased by vasopressin. suggesting that their movement is through similar pathways. It is suggested that ethanol empedes the flow of water across the toad bladder by facilitating a physicochemical interaction between the membrane "pore" and the water molecules.

Animals↗
PubMedDate not supplied

[Temporal characteristics of bacteriorhodopsin as a molecular biological generator of current].

Generation of electric potential difference by bacteriorhodopsin proteoliposomes incorporated into the phospholipid-impregnated collodion film has been studied. It is shown that illumination of this film by continuous light gives rise to the generation of an electric potential difference across the film (plus on the bacteriorhodopsin-free side), which can be as high as 300 mV. Short unsaturating flash inducing single turn-over of bacteriorhodopsin generates the potential difference which is a function of the flash intensity (70 mV at 3 mjoule light). The flash-induced photoelectric response consists of four phases. (1) Very fast (tau less than 1 microsec) generation of a potential difference (minus in the bacteriorhodopsin-free compartment). The amplitude of this phase is rather small (1--5 mV). (2) Fast phase of positive charging of the bacteriorhodopsin-free compartment (tau = 25--50 microsec). (3) Slow phase of positive charging of this compartment (tau = 6--12 msec) Amplitude of the second phase is to that of the third as 1 : 2. (4) A very slow phase of discharge of the flash-induced potential difference (tau = 1 sec at 10(8) ohm X cm2 film resistance). The third phase was specifically inhibited by La3+. Both the second and the third phases are decelerated by substitution of D2O in 4.5--5 and 2 times, respectively, while the amplitude of the first phase increases. Prolonged storage of the system in the dark (tua = 20--25 min) causes the decrease in the amplitudes of the second and the third phases as if the amount of active bacteriorhodopsin molecules were increased by factor 2. Such an inhibition was reversed by 30--60 sec illumination of the system. The dark adaptation is accompanied by some increase in the first phase amplitude. Comparison of these data with results of other studies on bacteriorhodopsin suggests that (1) the first phase is due to the photoinduced change in the retinal dipole; (2) the second phase corresponds to H+ transfer from Schiff base to the water solution in the proteoliposome interior; 3) the third phase represents H+ transfer from the incubation mixture to Schiff base; (4) the dark adaptation is a result of transition of photoelectrochemically active all-trans-retinal to the inactive 13-cis-retinal.

Bacteriorhodopsins↗
PubMed1983

Effect of visual deprivation on protein and nucleic-acid content in cerebral cortex of rats after the eye-opening term.

Between postnatal days 10 and 16 the cerebral cortex of rats displayed a rise in protein content and a tendency towards RNA increase, whereas changes in DNA content (cell density) were absent. Young rats whose eyelids had been sutured and covered with black collodion at the age of 7 or 8 days exhibited some developmental retardation already by day 16. At an age of 5 weeks the brains of control, eyelid-sutured and dark-reared rats did not differ in their weight. However, dark-reared rats had a highly significantly increased RNA concentration in the occipital cortex (not differing significantly from controls) than eyelid-sutured animals (p less than 0.005). In the remainder of cortex, eyelid-sutured animals displayed an increase (p less than 0.10) of RNA concentration as compared with controls. The most pronounced intergroup differences were found on comparing RNA, DNA and protein concentrations between occipital and residual cortices within the individual animal groups. The difference was practically nil in control animals; all components were highly significantly raised (RNA: p less than 0.001; DNA: p less than 0.01; protein: p less than 0.001) in the residual cortex in eyelid-sutured animals; dark-reared animals displayed a similar tendency as eyelid-sutured animals that, nevertheless, did not reach statistical significance.

Animals↗
PubMed1980

[Preparation of samples of biological fluids for electron spin resonance (ESR) examination].

The ESR (Electron Spin Resonance) Technique, is usually used in the study of Free Radicals and Metal - Proteins, in biological fluids, but the most apt method for the preparation of the sample has still to be defined. In this work the A.A. describe and analyse the negative and positive aspects of several methods. The results of the E.S.R. spectra, obtained by means of lyophilization, that is the most used method in literature, have been compared with those obtained by means of concentration of some biological fluid (serum and synovial fluid). The A.A. demonstrated that the lyophilization does not permit the reproducibility of the spectra, for different spectra are obtained from the same lyophilized serum and synovial fluid samples. A high reproducibility of the spectra is instead obtained by the concentration of the sample means of the "collodion bag" or "Aquacide" methods. The A.A. are convinced that for on exact investigation of the E.S.R. Signals, only the concentration method is useful, and not the lyophilization method as reported in literature.

Blood Chemical Analysis↗
PubMed1984

Clinical trials with Staphylococcus aureus and protein A in the treatment of malignant disease.

Perfusion of plasma from tumor-bearing animals over Staphylococcus aureus with membrane-bound protein A has resulted in significant tumor shrinkage. Similar therapy has now been given to 16 patients by three methods. No tumor responses have been observed. Five patients were treated with perfusion over fixed and killed S. aureus Cowan I. Cardiovascular and respiratory toxicity was excessive and appeared to be related to volume and rate of plasma infused. Eight patients were treated with perfusion of autologous plasmas over protein A-collodion-charcoal. Doses of plasma ranged from 50 to 450 ml. No toxicity was noted. Three patients have been treated with perfusion over protein A-silica. Toxicity in two resembled that seen in the S. aureus trials, although it was not as severe. We conclude that the toxicity of this therapy can be life-threatening, and human trials should be undertaken with caution.

Humans↗
PubMed1984

Tumoricidal response following perfusion over immobilized protein A: identification of immunoglobulin oligomers in serum after perfusion and their partial characterization.

Previously, we showed that perfusion of plasma from hosts bearing breast adenocarcinoma over immobilized staphylococcal protein A resulted in objective tumor regressions. In the present study, sera perfused in vitro over immobilized staphylococcal protein A were analyzed by physicochemical and immunochemical methods to characterize newly formed products. Sera from normal and breast adenocarcinoma-bearing dogs showed increased levels of C1q-binding IgG after perfusion over a strain of staphylococcus that is protein A rich (Cowan I), but not protein A deficient (Woods 46). C1q binding levels were also increased in normal and tumor-bearing canine or human sera which were perfused over purified protein A immobilized in collodion charcoal (PACC), and this increase was localized in sucrose density gradient fractions ranging from 7S to 19S. Polyacrylamide gel electrophoresis analysis of the high-molecular-weight fraction in postperfusion canine sera, isolated by G-200 fractionation and immunoaffinity chromatography, showed predominantly heavy and light immunoglobulin chains of canine IgG. Furthermore, protein A was released from PACC after perfusion with serum or solutions containing IgG or albumin from humans, dogs, and chickens. After serum perfusion over PACC, protein A was identified in the effluent by additional studies as follows: (a) polyacrylamide gel electrophoresis analysis showed that eluted 125I-protein A comigrated with the protein A marker; (b) postperfusion C1q-binding complexes, isolated by gel filtration under dissociating conditions and affinity chromatography on IgG-Sepharose showed a single precipitin band with normal human (protein A reactive) but not chicken (protein A unreactive) serum. Protein A released from PACC which appeared in postperfusion sera was associated with immunoglobulins in macromolecular complexes since (a) eluted 125I-protein A was largely (NH4)2SO4 and polyethylene glycol precipitable, whereas free protein A was not, and it sedimented in sucrose density gradient fractions distributed beyond the 7S marker, compared to free protein A which localized below 7S; (b) radiolabeled protein A eluting from PACC after serum perfusion showed 8-fold greater binding to C1q-coated tubes compared to free protein A; and (c) increased C1q-binding IgG in postperfusion sucrose density gradient fractions corresponded to the appearance of protein A in parallel gradient fractions.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗
PubMed1983

The electron microprobe analysis of sprayed microdroplets of solubilized biological tissues: a useful preliminary to localization studies.

The TEM-EDS bulk-tissue analysis procedure described involves: (1) low-temperature oxygen-plasma ashing of soft tissue specimens weighing greater than 20 micrograms in aluminum-foil crucibles; (2) the solubilization of the ash in 5 microliter 0.5N HNO3 containing a known quantity of cobalt as an internal, non-interfering reference element; (3) the spraying of the solubilized ash from glass microcapillary tubes onto thin carbon-collodion films mounted on titanium grids; (4) EDS analysis of individual microdroplets approximately 3 micron in diameter; (5) the quantitation of elemental concentrations from the element: cobalt intensity ratio by the "ratio model" technique. This technique was assessed and found to yield linear curves (greater than or equal to 0.999) for elements in 'artificial tissue' standards (concentration range = 5 - 340 mM kg-1 dry weight). The overall reproducibility of the technique is therefore quite good (e.g. error of 4.7% for P and K in 25 analyses) within the range of concentrations expected for most of the major biological elements encountered in vertebrate and invertebrate soft tissues. Absolute accuracy can be improved with quantitative procedures that account for peak-overlapping and escape peak contributions etc., so that the ultimate MDL for sodium may well be of the order of 1 mM kg-1 dry weight. The usefulness of the technique for the provision of basic biochemical information (especially in invertebrate systems which have received but meagre attention) is illustrated: (a) by comparing the calcium content of male and female blood-flukes (Schistosoma mansoni) in mixed-sex and unisexual laboratory infections; and (b) by determining the changes induced by daily injections of the drug Astiban on the element composition of female Schistosoma. We conclude that the technique can represent a useful multi-element detection facility which offers certain pertinent advantages over alternative microchemical techniques, such as atomic absorption spectrophotometry.

Animals↗
PubMed1984

Histological and ultrastructural changes in breast adenocarcinoma after treatment with plasma perfused over immobilized protein A.

Administration of plasma perfused over Protein A immobilized in collodion-charcoal produced focal acute tumor necrolytic reactions in breast adenocarcinomas. With repeated procedures, objective tumor regressions were observed in four of the first five consecutive patients treated. Within 4 to 48 hr after treatments, tumors became hyperemic and edematous, often with the appearance of focal vesicles. Microscopic and ultrastructural evaluation demonstrated a spectrum of lesions in cytoplasm and nucleus of tumor cells indicative of lethal and sublethal changes. With further treatments, more pronounced degenerative changes in individual tumor cells, tumor nodules, and intervening stroma were apparent. Furthermore, increased luminal and abluminal vesiculation of endothelial cells of postcapillary venules adjacent to tumor nodules was noted. With continued treatments at intervals of 2 to 3 days, some tumor sites showed focal mononuclear cell infiltration, and at the conclusion of plasma perfusion treatments previously ulcerated tumor foci were replaced by granulation tissue. These data suggest that several cytotoxic and inflammatory mechanisms are activated simultaneously or in succession and may account for the tumoricidal effects noted following repeated plasma perfusions.

Adenocarcinoma↗
PubMed1981

[Synthesis and physico-chemical properties of lonazolac-Ca, a new antiphlogistic/antirheumatic agent].

Calcium-[3-(p-chlorophenyl)-1-phenylpyrazole-4]-acetate (Lonazolac-Ca, active principle of Irritren) is a new antiinflammatory/antirheumatic agent whose synthesis and physico-chemical properties are described. The physical parameters measured (pKa, partition coefficient P, saturation concentration Cs, surface activity, protein binding) are held against the corresponding values of indomethacin, diclofenac, and phenylbutazone. The size of the permeability coefficient PM of the passive transport through artificial phospholipid collodion membranes as well as the invasion curves calculated from PM indicate a good absorption of lonazolac in man.

Acetates↗
PubMed1982

The development of a new hemoperfusion column: the filmadsorber.

A hemoperfusion system has been developed in which very small charcoal particles (average diameter 40 micrometers) are embedded and immobilized in a collodion film (Filmadsorber). In vitro studies revealed that the absorption of bile acids by these small charcoal particles is superior to that by larger ones (size: 0.5 to 5 mm) as used in commercially available adsorbers. In vivo studies confirmed these results: dogs with ligated bile ducts were subjected to hemoperfusion through different types of charcoal adsorbers. Bile acid clearances of filmadsorbers containing less charcoal than the commercials were significantly higher.

Animals↗
PubMed1994

[Serial changes of atelectasis in acute bronchial obstruction: MR imaging pathologic correlation in experimental animal model study].

OBJECTIVE: To evaluate MR imaging (MRI) of atelectatic lungs caused by acute bronchial obstruction. SUBJECTS AND METHODS: In 12 Japanese white rabbits, sudden obstruction of one main bronchus was induced with compressed polyvinyl-alcohol sponge plugs, and three rabbits each were sacrificed at 3, 7, 14, and 21 days. Unilateral complete airway obstruction persisted in 8 of the 12 rabbits. After T1: [500/20/2 (TR/TE/excitations), 5 mm thickness, 12cm FOV] and T2: [2500/80/4,5mm thickness, 12cm FOV] weighted imaging, both lungs and heart were inflated, fixed (Heitzman's method) and embedded en bloc in collodion. MR images of the atelectatic portion were evaluated, and MRI findings of the atelectatic portion were correlated with pathologic findings. RESULTS: MRI, especially T2 weighted images showed some characteristic signal patterns in each period. Correlations of these MRI features were performed with the pathologic findings: 1) The peripheral pulmonary parenchyma, on T2 weighted images showed signal increase with time which was attributed to edematous fluid retention in pulmonary alveoli. 2) The difference between inhomogeneous and homogeneous signal intensities on T2 weighted images on the 7th day was attributed to the patchy and even distribution of inflammatory process in pulmonary parenchyma. 3) On the 21st day, hypointensity bands were observed on T1 and T2 weighted images. These hypointensity bands were attributed to fibrotic changes in bronchial walls and nearby alveolar walls. CONCLUSION: MR images well demonstrated pathological changes in atelectatic lungs caused by acute bronchial obstruction with time, suggesting the clinical usefulness of this approach.

Acute Disease↗
PubMed1994

Preliminary report on cell encapsulation in a hydrogel made of a biocompatible material, AN69, for the development of a bioartificial pancreas.

The occurrence of an inflammatory reaction represents the major obstacle to the development of any implantable system including micro and macroencapsulation. The purpose of this study was to describe an encapsulation method for cells using a membrane made of AN69, a copolymer of acrylonitrile which is considered as a reference in biocompatibility in the field of haemodialysis. The hydrogel of AN69 was obtained after a coagulation step at room temperature followed by a solvent/non-solvent (water) exchange phase. Microcapsules were obtained by co-extrusion of AN69 collodion and saline (with or without cells). The function of encapsulated cells was assessed in vitro, demonstrating cell survival after the microencapsulation procedure. These preliminary data are consistent with the potential interest for the development of the microencapsulation procedure aimed at realising a bioartificial pancreas.

Acrylic Resins↗
PubMed1995

The covering method: an improved negative staining method for ultrathin cryo-sections of tissue.

Ultrathin cryo-sections of biological tissues for electron microscopy provide numerous advantages in cytochemical and morphological studies. However, difficulties still remain in the application of negative staining to cryo-sections. This paper describes a method for negative staining of cryo-sections by covering the grid with a piece of either Collodion or Formvar film. By doing so, appropriate amount of staining solution is retained on the grid for positive effects. Also, the present method requires only a few seconds to stain the ultrathin cryo-sections while previously published methods took up to 10 min.

Animals↗
PubMed1996

[An analysis of the late results in the surgical treatment of patients with complex combined nasal deformities].

Analysis of late results showed that satisfactory and unsatisfactory results are most frequent (70%) in patients with combined deformations of the nose. The principal causes of recurring deformations after rhinoplasty are a) absence of adequate internal fixation of both the dislocated pyramid and the mobilized nasal septum; b) omitting the mobilization of the bone part of the septum in case of its deformation; c) unjustified wide use of methods of mobilization of crossing incisions on the cartilaginous part of the septum; d) no correction of thick porous skin at the end part of the nose; e) use of costal allocartilages in slight retractions of the cartilaginous part of the ridge of the nose which are contoured at the interface, dislocated, and deformed; f) use of costal allocartilages as rafters in flattened noses makes the end part of the nose thickened and little mobile; and g) use of collodion dressing does not meet the requirements of fixation, particularly so in the bone part of the ridge. Hence, analysis of late results showed that some of the routinely used methods should be revised.

Adolescent↗
PubMed1977

Temporal artery catheterization for arterial access in the high risk newborn.

The hazards of umbilical artery catheterization necessitate the adoption of an alternate arterial cannulation site for monitoring arterial pressure and oxygen tension in the critically ill newborn. A newly developed method of catheter placement in the temporal artery not only provided arterial access for substantially longer than that reported for radial artery cannulation, but more than 50% of the infants in which it was performed weighted less than 1500 grams. Close adherence to the technique of arterial cannulation and catheter fixation is essential for prolonged arterial access. The method involves (1) Doppler location of the temporal artery, (2) a 3 mm transverse incision directly over the vessel, (3) bevel-down insertion of a winged hub teflon catheter with inner needle stylet, (4) securing the catheter with suture and collodion, and (5) maintenance of catheter patency with a constant infusion of heparinized solution. Temporal artery cannulation using this technique has been performed thus far 115 times in 100 infants with severe respiratory distress. The patients weighed between 540 and 3900 grams. Catheters remained operational for an average of 6.5 days (8 hours to 23 days), with 62% of all catheters providing arterial samples for more than 5 days. The cannulas worked well for arterial pressure monitoring, and pulse contour matched that of the umbilical artery in infants with catheters in both vessels.

Blood Pressure↗
PubMed1997

Application of AN69 hydrogel to islet encapsulation. Evaluation in streptozotocin-induced diabetic rat model.

The polymer AN69 (polyacrylonitrile-sodium methallylsulfonate) is a reference in biocompatibility in the field of hemodialysis. Its use for the encapsulation of living cells has been already described, but this study is the first description of AN69 hydrogel-encapsulated islet isograft in streptozotocin (STZ) diabetic rats. The aim of this work is to evaluate the biocompatibility of the AN69 hydrogel by comparison of the efficacy of free versus encapsulated islets transplanted to balance diabetes. Pancreatic islets are isolated from adult male Lewis rats by a standard collagenase digestion and purified on Ficoll density gradients. The AN69 hollow fiber is obtained by coextrusion of an 8% AN69 collodion. The hollow fiber is filled with islets suspended in agarose at the final concentration of 10,000 islets/ml, closed with surgical clips and implanted. The recipients are rendered diabetic by intravenous injection of STZ. The experimental design includes 4 groups of 8 rats: group 1: control, group 2: diabetic rats intraperitoneally implanted with 6000 free islets, group 3: diabetic rats intraperitoneally implanted with 9000 encapsulated islets, group 4: diabetic control. Weight and fasting glycemia are evaluated twice a week, diuresis once a week. After free islet implantation, rat survival is improved with glycemia below 250 mg/dl during 22 days. Compared to group 2, the status of group 3 is better, with a glycemia below 250 mg/dl during at least 70 days. This tends to demonstrate the biocompatibility of AN69 and is the first step of the validation of the use of AN69 for living cell encapsulation.

Acrylic Resins↗