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At least 19 recordsLinked to original sources
PubMedDate not supplied

The effects of barium sulfate on the polymerization temperature and shear strength of surgical simplex P.

Barium sulfate additive, in amounts ranging from 5% to 60%, causes a progressive reduction in polymerization temperature of the cement without appreciably altering the polymerization time. Concurrently, the mechanical strength of the cement, as determined in shear, decreases with increasing concentration of barium additive. Although inclusion of barium sulfate in acrylic bone cement is primarily used for radiographic contrast purposes, its possible effects on release of monomer and other local mechanisms seem not to have been measured.

Barium Sulfate↗
PubMed1977

[Clinical-radiological evaluation of barium sulfate suspension in double contrast examination (author's transl)].

In four selected, commercial barium sulfate preparations, viscosity, surface tension and particle size were measured; examined were agglomeration, sedimentation and homogeneity in vitro. For the clinical-radiological examination, an evaluation scheme has been developed containing the following criteria: uniformity and thickness of contrast medium layer, demonstration of the areae gastricae, clearness of gastric contour, and vesiculation. A blind study, encompassing about 100 double contrast examinations of each preparation, ascertained the usability of this scheme. Significant differences could be detected among the four contrast media. The barium sulfate suspension which was rated the highest lay within a viscosity range of 50-90 cP, had a particle diameter of 0.2-1.6 micrometer and showed the least degree of agglomeration. Results of the in vitro examinations, when compared to the clinical tests, lead to the conclusion that both, gastric mucous and contrast medium additives, may exert considerable influence on the pictorial quality of the above defined criteria.

Barium Sulfate↗
PubMed1977

Stimulation of sugar uptake and thymidine incorporation in mouse 3T3 cells by calcium phosphate and other extracellular particles.

Evidence is presented that the marked stimulation of sugar uptake and thymidine incorporation by addition of extra Ca2+ to stationary phase mouse 3T3 cells in culture is phosphate dependent and due to the action of the calcium phosphate precipitate formed in the medium. The cells are similarly stimulated by a variety of particulate materials, including calcium pyrophosphate, barium sulfate, kaolin, and polystrene beads. The precipitate effects on sugar uptake are of the same magnitude as those seen with certain hormones (insulin, epidermal growth factor) or with fresh 10% calf serum. The effect of barium sulfate on thymidine incorporation is also of the same magnitude as seen with these hormones, but much less than half that found with fresh calf serum. The stimulation by barium sulfate or hormones of thymidine incorporation is not phosphate dependent.

Barium Sulfate↗
PubMed1977

A comparative double-blind study of esophageal barium pastes.

To demonstrate esophageal varices barium sulfate suspensions must coat the lower esophagus for as long as 5 to 10 minutes. This study compared the ability of five barium sulfate preparations to resist disappearance by inadvertent swallowing. Three of the special preparations for esophageal examination, Esophatrast, Barosperse Esophageal Paste, and HD-5000 performed satisfactorily. Examiner skill, persistence, and careful technique are the most important factors in examining the lower esophagus. The authors' procedure for examination of the esophagus for varices is described. It takes into account position, time, phase of respiration, occasional use of drugs, and procedures to insure good coating and relaxation of the lower esophagus.

Barium Sulfate↗
PubMed1977

Evaluation of intracytoplasmic particles in histiocytes after endodontic therapy with a hydrophilic plastic.

The presence of granules within the cytoplasm of periapical tissue histiocytes had been observed in teeth which had a root canal overfilled with a hydrophilic plastic polymer. SEM examinations revealed these granules to be barium sulfate, which was added to the polymer for radiopacity. X-ray spectra revealed strong calcium peaks in bone adjacent to the histiocytes, which showed strong barium peaks. In addition, between the histiocytes and the bone a greater concentration of calcium was seen. Because the histiocytes and not the plastic polymer contained barium sulfate, the evidence for this material's biocompatibility is greatly enhanced.

Animals↗
PubMedDate not supplied

Microangiography in the perfusion-fixed rabbit kidney: a single injection technique for the study of the nephron.

Through the modification of a technique developed by Beeuwkes, microangiography, using barium sulfate, was performed on rabbit kidneys following perfusion fixation with gluteraldehyde. Gluteraldehyde is a rapid fixative which preserves tissues while creating few artifacts on the electron microscopic level. The vessels and tubules are preserved in an open-lumen state with sufficient hardness to resist the artifacts caused by high pressure renal artery injections. By injecting barium sulfate at high pressure through the renal artery it is postulated that microruptures are created in the glomerular tuft. This leads to opacification of the tubules and the demonstration of various anatomic configurations. Low pressure injections were used to selectively demonstrate the vascular anatomy. This method allows the demonstration of the vascular and tubular anatomy without specialized techniques. The mechanism of failure of opacification of the renal vein on conventional microangiography are discussed.

Angiography↗
PubMed1975

Pulmonary pressure- volume relationships after corticotropin (ACTH) and salin injections in fetal rabbits.

ACTH mixed with barium sulfate injected into fetal rabbits on day 24 of a 31-day gestation was associated with increased lung maturity compared with lungs of noninjected controls when assessed by deflation pressure-volume curves and lung weight to body weight ratios measured on day 27. Fetuses injected with saline and barium sulfate also had accelerated (although somewhat less) lung maturation, perhaps from an ACTH-mediated response to stress. The ACTH group LA) maintained the largest lung volumes on deflation, followed by the saline group (B), the ACTH controls (C), and the saline controls (D). Volumes (percentage of total lung capacity) between the two injected groups and their controls (A versus C; B versus D) were significantly different at transthoracic pressures of 15, 10, 7, 4, 0, and -2 cm water (p less than 0.05). Volumes (percentage of total lung capacity) between the ACTH group and the saline group (A versus B) and between the two controls groups (C versus D) were not significantly different. Wet lung weight to body weight ratios were significantly different between the injected groups and their respective controls, between the two injected groups, and between the two control groups.

Adrenocorticotropic Hormone↗
PubMed1979

Simple metallic compounds as pulp-capping agents.

A study is described in which six metallic compounds identified in a previous pilot experiment were tested as pulp-capping agents using the exposed rat molar. Barium sulfate, calcium carbonate, cupric oxide, ferric oxide, and heavy magnesium oxide gave poor results. Stannic oxide gave more favorable results and is being studied further.

Animals↗
PubMed1977

The structure of mononuclear phagocytes differentiating in vivo. III. The effect of particulate foreign substances.

The response of mononuclear phagocytes to three inert particles--barium sulfate, talc, and thorium dioxide--was studied by correlated light and electron microscopy. All three particles induced maturation of the mononuclear phagocytes, which proceeded to the stage of the mature macrophage and required 7 to 9 days. Once established, maturation persisted as long as 45 days, as did the inert particles. The resultant lesions, dense aggregates of mature macrophages, were termed mature granulomas. The resultant maturation differed from that produced by digestible bacteria in tempo and extent but not in pattern.

Animals↗
PubMed1979

Purification and partial characterization of an alpha-chymotrypsin-like protease of rat peritoneal mast cells.

An alpha-chymotrypsin-like enzyme was isolated from mast cells of the rat peritoneal cavity by extraction with 0.8 M potassium phosphate, 2 per cent protamine sulfate followed by affinity chromatography on hen ovoinhibitor-agarose and adsorption on barium sulfate. This procedure yielded over 9 mg of protease from the peritoneal lavage fluid of 100 rats, equivalent to 44 per cent of the initial activity. The purified protein was homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, analytical isoelectric focusing, and amino-terminal sequence analysis. The protease contains no covalently bound carbohydrate and has a molecular weight of approximately 26,000. The enzyme molecule is a single polypeptide chain with an amino-terminal sequence homologous to that of the B chain of bovine alpha-chymotrypsin. The kinetic parameters, Km and kcat, for the hydrolysis of N-benzoyl-L-tyrosine ethyl ester were determined at pH 8.0 and 25 degrees C as 1.1 X 10(-3) M and 84 sec-1, respectively. The value of the second-order rate constant for inactivation of mast cell protease by diisopropylphosphofluoridate was 300 times lower than for bovine alpha-chymotrypsin.

Amino Acid Sequence↗
PubMed1978

Purification and properties of the phenprocoumon-induced decarboxyfactor X from bovine plasma. A comparison to normal factor X.

1. By a procedure involving adsorption to barium sulfate, chromatography on DEAE-Sephadex and QAE-Sephadex and preparative polyacrylamide gel electrophoresis, decarboxyfactor X was purified from plasma of phenprocoumon-treated cows. No contaminants could be detected in the final preparation by polyacrylamide gel electrophoresis and zone-electrophoresis. 2. The molecular weight of decarboxyfactor X, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis is approximately 55 000, which is equal to that of factor X. The protein consists of two polypeptide chains with molecular weights of 44 000 and 17 000. 3. Decarboxyfactor X has antigenic determinants in common with normal factor X. 4. The amino acid composition and aminoterminal amino acids of normal factor X and decarboxyfactor X are identical. 5. Less than one residue of gamma-carboxyglutamate could be detected per mole of decarboxyfactor X. 6. In the absence of Ca2+, normal factor X has a slightly higher electrophoretic mobility than decarboxyfactor X. In the presence of Ca2+ the mobility of factor X decreases considerably while the mobility of decarboxyfactor X remains unaltered.

4-Hydroxycoumarins↗
PubMed1977

Simple metallic compounds as pulp-capping agents. A pilot study.

A pilot study is described in which the exposed pulps of molar teeth of normal laboratory rats were capped with various metallic compounds in general medical usage. There appeared to be no relationship between the response obtained and the pH of the compounds studied. Aluminum powder, aluminum hydroxide, Aludrox, aluminum oxide, light magnesium oxide, magnesium hydroxide, and titanium dioxide gave poor results. Barium sulfate, calcium carbonate, cupric oxide, ferric oxide, heavy magnesium oxide, and stannic oxide merited more detailed study.

Animals↗
PubMed1978

A microangiographic study of vascular changes in replanted and autotransplanted teeth of young dogs.

The purpose of the present investigation was to study the revascularization process of the pulp of replanted and autotransplanted teeth with incomplete root development in dogs. A barium-sulfate injection method combined with contact microradiography was used. Ingrowth of apparently new vessels was seen during the first postoperative days. After 10 days, visible vessels were seen in the apical half of the pulp, and after 30 days, in the whole pulp. Branches and apparently also anastomoses between pulpal vessels were seen after 10 days but were especially numerous after 30 days. One hundred eighty days postoperatively, only one of fifteen teeth was devoid of visible vessels, indicating pulpal necrosis. Thirteen of the remaining fourteen teeth exhibited visible vessels throughout the entire length of the pulp. It seems, therefore, that replanted and autotransplanted teeth with open apices have a high potential for repair. The revascularization of the pulp appeared to occur mainly by ingrowth of new vessels. In some instances, however, anastomoses seemed to form to pre-existing vessels in the pulp.

Animals↗
PubMed1979

Carbon-13-enriched carbohydrates: preparation of triose, tetrose, and pentose phosphates.

Three-, four-, and five-carbon aldononitrile phosphates were prepared, purified, and catalyticlly reduced with palladium--barium sulfate (5%) to the corresponding aldose phosphates in high yields at pH 1.7 +/- 0.1 and atmopsheric pressure. DL-Glyceraldehyde 3-phosphate and the tetrose 4-phosphates were prepared with carbon-13 enrichment at C-1, while the pentose 5-phosphates were prepared with enrichment at C-1 and C-2. Preparations of glycolaldehyde phosphate and d-glyceraldehyde 3-phosphate by lead tetra-acetate oxidation of glycerol phosphate and fructose 6-phosphate, respectively, are described. The proportions of cyclic hemiacetals and linear gem-diol forms of the two- to five-carbon aldose phosphates in aqueous solution are reported. Carbon-13 chemical shifts and carbon--phosphorus and carbon--hydrogen coupling constants for the furanose phosphate ring and linear gem-diol phosphates are reported and discussed. d-[2(-13)C]Ribulose 1,5-bisphosphate and L-[3,4(-13)C]sorbose 1,6-bisphosphate were prepared enzymatically from D-[2(-13)C]ribose 5-phosphate and dl-[1(-13)C]glyceraldehyde 3-phosphate, respectively.

Carbohydrate Epimerases↗