Showing papers on "Blisters published in 1978"

Freeze-fracture studies of the developing cell surface. II. Particle-free membrane blisters on glutaraldehyde-fixed corneal fibroblasts are artefacts.

Abstract: We describe, in sections and by freeze-fracture, four classes of intramembrane particle (IMP)-free membrane blebs or "blisters" associated with glutaraldehyde-fixed embryonic corneal fibroblasts: (a) Single blisters attached to the cell membrane; (b) free (detached) vesicles; (c) myelin figures; (d) multivesicular protrusions which resemble the "mounds" described by others on nerve growth cones. The IMP-free, membrane-bounded blisters contain no ground cytoplasm or organelles, in contrast to blebs on trypsin-isolated fibroblasts, which we show here do contain cytoplasm and IMP-rich membranes. That the IMP-free membrane blisters in embryonic corneas are artefacts of fixation is demonstrated by (a) their absence in replicas of fibroblasts frozen and fractured without prior aldehyde fixation and (b) their absence in sections of fibroblasts fixed in a combination of glutaraldehyde and osmium tetroxide. We suggest that the addition of osmium prevents postfixation movement of membrane lipids, especially the negatively charged "fluid" lipids which others have shown are capable of considerable mobility after aldehyde fixation alone. Recent literature has implicated membrane blistering in secretory processes and in growth of nerves, but before the functional significance of such IMP-free blisters is assessed, membrane mobility of the type shown here should be taken into consideration.

The extension of hydrogen blister-crack array in linepipe steels

Abstract: Hydrogen induced fracture in linepipe steels is characterized by the formation of internal blisters caused by hydrogen precipitation at an inclusion-matrix interface, followed by the formation of blister-crack array by cracking the region connecting the blisters through the action of internal hydrogen pressure and external stress. The manner of extension of the hydrogen induced fracture of this type is considerably influenced by the presence of external stress: in the absence of the external stress fracture develops by linking the blisters which are formed in stacked arrays out of a plane approximately perpendicular to the external stress axis. Shear stress distribution induced around the blister is sensi-tively influenced by the external stress applied parallel to the blister plane; therefore, it is expected that the manner of extension of the blister-crack array should be influenced by the external stress. In the present paper the above mentioned influence of the external stress on the manner of extension of the hydrogen induced fracture is explained based on stress analysis around a hydrogen gas pressurized crack-like cavity under stress.

Transfer of penicillin G and ampicillin into human skin blisters induced by suction.

Abstract: The antibiotic concentrations in untreated and endotoxin-treated suction blisters was studied in 15 healthy adults. In a pilot study, 2 mega units of penicillin G were given as an intravenous bolus injection to two subjects. For further studies, a single dose of 800 mg bacampicillin was given orally to 13 individuals. The penicillin G concentrations in the blister fluid were highest approximately 15 minutes after the dose, and exceeded that of serum after 1.5 hours. With ampicillin the blister fluid concentration reached maximum levels after approximately 2 hours, were equal to serum levels after 3 hours, and were later persistently in excess of serum levels. The ampicillin half-life was 136 and 100 minutes in the two types of blister fluid, as compared to 65 minutes for serum. A marked differences between the antibiotic concentrations in inflammatory and non-inflammatory blisters was seen in the pilot study with penicillin G. However, in the experiments with bacampicillin, no significant difference was demonstrated. This suction blister technique appears to be a useful method for studies on extravascular antimicrobial activity in man.

Suction blister fluid as a model for interstitial fluid in rats

Abstract: 1. Suction blisters on the skin of rats, obtained with a negative pressure of 150 mm Hg, show a close similarity to human suction blisters, based on histological, electrolyte and protein findings. 2. Pharmacokinetic experiments with inulin and antipyrine have proved that the movement of these low protein binding drugs between blister fluid and serum follows the laws of diffusion. 3. The investigations suggest that blister fluid resembles interstitial fluid and can therefore serve as a model for the estimation of drug concentrations in interstitial fluid.

Membrane blisters: A fixation artifact a study in fixation for scanning electron microscopy

Abstract: It is been shown by scanning electron microscopy that fixation in glutaraldehyde followed by fixation in osmium tetroxide results in the presence of membrane blisters on the surface of a variety of cells. Fixation in glutaraldehyde alone or osmium tetroxide alone does not result in such extensive artifacts. The blisters, usually 0.2–0.6 μm in diameter, are seen by transmission electron microscopy to be membrane-bound, virtually empty vesicles. It is concluded that the optimum preservation of the cell surface for scanning electron microscopy is provided by fixation in glutaraldehyde alone.

Correlation of blister diameter and blister skin thickness for helium‐bombarded V

Abstract: A correlation of the most probable blister diameter Dmp and mean blister skin thickness t for helium‐ion‐irradiated annealed polycrystalline and monocrystalline V (100) surfaces yields a relationship Dmp∝t0.89. This relationship is different from the relationship Dmp∝t1.5 suggested by other authors for vanadium. The relationship observed in the present studies does not support the lateral stress model for blister formation, which predicts Dmp∝t1.5. Evidence is presented for blister formation by internal gas pressure, as suggested earlier by the present authors.

Acid hydrolases in blister fluid. 4. Influence of ultraviolet radiation.

Abstract: Large, dose-related increases have been demonstrated in the activity of lysosomal hydrolases in the fluid of experimental suction blisters raised on skin previously irradiated with UVR-B. These increases appear after a latent period of 11--18 h, and the pattern of changes shows an extremely good correlation with the hydrolase profile of epidermis. These observations offer strong support for the concept that lysosomes participated in the sequence of events following UV irradiation, but seem to rule out the lysosome as the initial target for UVR.

Blistering effects in argon‐bombarded silicon

Abstract: Blistering of silicon due to argon bombardment has been observed at implantation energies above about 100 keV. Above about 200 keV rupture of blisters becomes the predominant surface damage phenomenon. Blistering effects are most obvious upon first appearance. Further bombardment causes the occurrence of new generations of blisters accompanied by oscillations in argon content of the silicon backing. The effects are interpreted in terms of argon agglomeration, build‐up of critical argon pressures, argon release from near‐surface regions, and sputtering.

Temperature dependence of helium blistering in nickel monocrystals

Abstract: The (110) and (111) planes of monocrystalline nickel targets have been bombarded with 500‐keV 4He+ ions under channeling conditions for a total dose of 6×1018 ions/cm2 and for target temperatures ranging from room temperature to 950 °C. The results indicate a decrease in average blister diameter with increase in target temperature. Large‐scale exfoliation of blister skin occurs at 300 °C, and, above 850 °C, holes are observed on the surface.

Helium Blistering in Metals

Abstract: In a fusion reactor, various parts will be exposed to an important flux of helium atoms. Under certain conditions this will cause blistering resulting in surface erosion and plasma contamination. Measurements of the following blister parameters: blister skin structure and thickness, helium depth distribution, and swelling are discussed. These data refer mainly to 10 to 20 keV He blistering of Nb and Cu where the blister skin is apparently two times thicker than in the ''gas pressure'' model. The observation of a depletion at the center of the helium distribution, of bubbles in the skin, and of approximately 40 percent swelling allow us to conclude that this model is still valid.

The induction of axial blisters in the chick embryo by trypan blue

Abstract: The hemorrhage, blister formation, and rumplessness observed in the chick embryo following treatment with trypan blue may be due to (1) increased ventricular blood pressure or (2) to necrosis and edema in the caudal region of the embryo by inhibiting nutrient utilization. To test the role of increased ventricular blood pressure in the induction of caudal blisters, primitive streak to 7-somite chick embryos were cut in half, separating the upper presumptive heart region from the lower presumptive trunk and tail regions. Each half was then explanted on media containing trypan blue for 24 hours. In intact embryos treated with 0.04 mM trypan blue the frequency of blisters in the posterior region was 80.8%. The blisters usually appeared on both sides of the neural tube, below or in the region of the last few somites. In transected embryos treated with trypan blue, the frequency of blisters in the posterior halves which had beating hearts was 2.6%. However, the frequency of blisters in the posterior halves which were not connected to beating hearts was 47.8%. In some cases the blisters were found in posterior halves in which the rump was not well developed or present at all. Thus, we may conclude that: (1) direct connection between the heart and the rump is not necessary for the induction of caudal blisters. (2) The presence of a well-differentiated rump is also not necessary for blister formation. We suggest that trypan blue acts directly on organs or structures found in the caudal region of the chick embryos.

Surface blistering of molybdenum irradiated with 75–350‐keV helium ions

Abstract: Polycrystalline molybedenum samples have been irradiated at room temperature with helium ions of energy from 75 to 350 keV in high vacuum. Irradiation parameters such as ion energy, total dose, and dose rate were varied and surfaces were examined in a scanning electron microscope. The average blister diameter increases with increasing ion energy and the blister number density increases with increasing total dose of helium. The critical dose for blister formation is independent of the beam flux in the range of 6.7×1013 to 2×1015 ions cm−2 s−1. However, the average blister diameter changes with the change of flux. When the molybdenum surface is successively bombarded with varying ion energies, both the diameter and the number density of the blisters is significantly reduced as compared to monoenergetic helium bombardment.

[Physical forces in blister formation. II. Examination of total osmolality in blister fluid of suction blisters, "naturally" developed blisters and in serum (author's transl)].

Abstract: Total osmotic pressure does not differ significantly in suction blister fluid or in serum of healthy persons from blister fluid, suction blister fluid or serum of patients with dermatitis herpetiformis, bullous contact dermatitis and pemphigus vulgaris. The average values reach about 293 mOsmol/kg. This results from direct measurement of total osmolality with an electronic semimicroosmometer based on the principle of freezing point reduction. In opposite to colloid osmotic pressure the total osmotic pressure does not take part in blister formation of human skin in spite of the different concentrations of the single electrolytes in the fluids of various blisters.

Localized corrosion of aluminum- blister formation as a precursor of pitting

Abstract: Blisters have been observed in the oxide film of aluminum in aqueous chloride solutions. They can be initiated by short duration (⪝ 1 msec), low voltage pulses. Such blisters grow only if the steady‐state potential of the specimen is above the pitting potential. The growth proceeds laterally along the oxide‐metal interface. Upon breaking, as a result of gas pressure from within, pitting corrosion begins. Thus, in this instance, blisters are experimentally demonstrable precursors of pits.

Prevention of blisters in coating film

Abstract: PURPOSE:On the baked primer or intercoating film are applied, in layers, two wet finish coatings each containing an ultraviolet light absorber in different amount to ensure blister prevention for long periods.