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At least 1,567 records · Page 87Linked to original sources
PubMed1978

[Studies on dental casting ferromagnetic alloys (author's transl)].

We previously reported successful applications of rare earth-cobalt magnets to dental prostheses. In order to use magnets more effectively, ferromagnetic materials with a high magnetic permeability and a high saturation flux density should be used as prosthetic materials. This type of material will form a good magnetic path, and consequently tighten the magnetic attracting force by preventing the magnetic flux from leaking into the mouth tissue. A few alloys were newly prepared by using Pd, Co and Cr, the usual dental metals, and tested. It was found that: (1) These alloys have suitable magnetic properties. (2) The corrosion resistances of the Pd-Co and Pd-Co-Cr alloys are as good as those of dental casting Ag and Ni-Cr alloys, respectively. (3) The physical and mechanical constants of the alloys are similar to those of the usual dental casting alloys. (4) These alloys can be used as dental casting ferromagnetic alloys. (5) The Pd-Co alloy can also be used as a porcelain bonding alloy.

Cobalt↗
PubMed1987

[The collector system of the kidney. Applied anatomy based on the analysis of 3-dimensional casts].

The kidney collector system were studied in 120 three-dimensional casts obtained by the injection-corrosion method. To the procurement of the first hundred casts, we made use of a polyester resin; however on the preparation of the last twenty we made use of a mixture containing latex and radiographic contrast as we intended to obtain, besides the casts, the roentgenograms. Two anatomic details, which have a great importance for endourology, were observed: a. the calices' cross draining the meso-renal region and the consequent inter-pelvis-calice (space (IPC) formation which is seen in the roentgenograms, b. a smaller calice which penetrates perpendicularly the surface of the renal pelvis or into the surface of a great calice. The urologists must appreciate these two anatomic structures, before the surgical procedures on the collector system.

Humans↗
PubMed1986

Scanning electron microscopic studies on microvascular architecture of human coronary vessels by corrosion casts: normal and focal necrosis.

Microvascular architecture of the normal human heart and myocardial focal necrosis were studied by scanning electron microscopy of corrosion casts. Casts macroscopically identical in form to the left ventricular posterior wall were prepared. The following results were obtained in the normal human heart. Most of the arterioles communicated with capillary plexuses smoothly and straightforwardly in the left ventricular posterior free wall. Arterioles which branched from the arteries ran in various directions and continued into capillaries either at right angles or obliquely in the trabeculae carneae. Capillaries running parallel with the cardiac muscle fibers ran in different directions to cross over with each other in different layers of myocardium. Capillaries in the myocardium formed a continuous and coarse net-like architecture with many bifurcations and anastomoses. Capillaries were about 5-7 micron in diameter. Some veins gathering capillaries in the epicardium ran into the myocardium and the others ran in the epicardium. Veins connecting with capillaries in the myocardium ran in the myocardial layer and communicated with larger veins. An arterio-venous anastomosis and two different types of venous-venous anastomoses were observed in the left ventricular posterior wall. At the site of focal necrosis, cross sections of dilated vessels were observed in large numbers by light microscopy and scanning electron microscopy. At the site of focal necrosis, dilated capillaries running with tortuosity were seen in large numbers by scanning electron microscopy of corrosion casts. When compared with vessels in the normal myocardium, small arterial branches were dilated and run tortuously. These dilated capillary plexuses were observed in the area which communicated with twigs branching off at the right angle from the arterial branch.

Capillaries↗
PubMed1986

Corrosion cast technique applied in lymphatic pathways.

The paper deals with methods and results of the microcorrosion cast technique in lymph angiology. For the representation of the special organization of the lymph vascular system including the initial vascular structures, intranodal pathways, bigger collectors, and lymph trunks, the application of various injection techniques is necessary. The interstitial injection of Mercox proves to be suitable to show the initial lymphatics and prelymphatic spaces. Similarly, the intranodal injection makes visible the system of the lymph sinuses and the spaces of the reticular tissue in this organ. Casts of bigger collecting vessels, lymph trunks, and thoracic duct can be obtained by direct injection of the resin into the vascular lumen. Thus, these techniques enable to make visible the structural details of the cast preparations of all parts of the lymphatic system.

Animals↗
PubMedDate not supplied

[Environmental and biological monitoring of subjects occupationally exposed to precious metals (gold lost-wax casting)].

Environmental monitoring during lost wax casting in jewelry handicrafts was performed for gold, silver, zinc and copper by means of personal samplers and ICP-AAS techniques were used for determining airborne metals. Personal sampling was prolonged for a working week by continuous monitoring during 8 hours shifts, replacing the membrane filter every 2 hours, in 6 workers; in the same workers urine samples were collected during the week and levels of Au, Ag, Zn and Cu were measured by ETA-AAS. During casting process Ag air concentrations ranged 0.27-0.6 mg/m3 while mean levels of Au, Cu, and Zn were 0.028 0.030 and 0.056 mg/m3 respectively. Urinary excretion of Ag (I) determined by solvent extraction and separation by liquid anion exchanger proved very high, after 24-36 h from the casting processes.

Adult↗
PubMed1985

Effect of simulated hyperemia on the flow field in a mildly atherosclerotic coronary artery casting of man.

The purpose of this investigation was to determine changes in the flow field due to mild atherosclerosis using a main coronary artery casting of man with maximum obstruction of about 50% by area. Local pressure changes were measured using six pressure tap holes drilled flush to the wall along the casting. The test fluid used was a 33% sugar-water solution to simulate the viscosity of blood. Flow visualization results were obtained by injecting blue dye slowly through the pressure tap holes. The local pressure measurements clearly demonstrated a significant Reynolds number effect. At physiological Reynolds numbers of 80-710, a local pressure rise was observed downstream of the mild atherosclerotic constriction of 50% because of momentum changes. The flow visualization study indicated that the critical Reynolds number for flow separation to occur in the divergent region of this coronary casting was about 330. Flow separation has been implicated in the genesis of atherosclerosis but there is little information on the extent of flow separations in vivo in arteries of man. These results are believed to be important in obtaining a quantitative relation between coronary morphology and the fluid dynamic consequences of mild diffuse disease especially under conditions of maximum cardiac demand i.e., higher coronary flow rates, and thus Reynolds numbers associated with space and/or atmospheric flight.

Blood Flow Velocity↗
PubMed1985

Hair casts. A clinical and morphologic study.

Idiopathic hair casts are described in two girls aged 5 and 7 years. A 0.025% tretinoin lotion seemed effective in removing the casts. Investigations, including light microscopy and transmission electron microscopy, suggest an infrainfundibular origin for these lesions, because both inner and outer root sheath components were observed in the transverse sections of the casts. A comprehensive review of the literature enabled us to classify the patients into two distinct groups: group 1 consisted of patients with idiopathic disease, showing a diffuse pattern of involvement, and group 2 consisted of patients with disease secondary to a variety of inflammatory scalp disorders.

Bezoars↗
PubMed1985

Use of polymer casts or metal particle infusion of ducts to study antigen uptake in the guinea pig mammary gland.

Microcorrosion casts were made of the duct system of guinea pig mammary glands by intramammary infusion of Mercox polyester resin following involution of the glands after the first lactation. The acinar configuration of the involuted gland was apparent on examination of the casts by scanning electron microscopy (SEM). Surface features, which were readily identified as those of imprints of ductal epithelium, were visible at higher magnifications. The morphology of these casts corresponded to the patterns observed by SEM of ethanol cryofractured specimens of mammary tissue. Cryofractured specimens of guinea pig mammary glands were also examined by SEM following intramammary infusion of tantalum. Tantalum particles were observed within the lumina of many ducts. Large phagocytic cells within the lumina were shown to contain tantalum by using back scatter imaging in conjunction with secondary imaging.

Animals↗
PubMed1984

Scanning electron microscopy of vascular casts in experimental ocular vasoproliferation.

Scanning electron microscopy of vascular casts was used to investigate three experimental models of neovascularization. In each experimental situation, the casts provided a valuable three dimensional representation of the newly formed blood vessels and permitted subclassification of the vessels within normal and proliferating vascular networks. They defined also the predominant origin of new vessels from venules and capillaries, and enabled the evolution of proliferating vessels into arterioles and venules to be documented. Although vascular casts must be interpreted with caution in light of the possibility of incomplete filling and other artifacts, they are a valuable tool in the study of ocular vasoproliferation.

Animals↗
PubMed1981

Tamm-Horsfall uromucoprotein and the pathogenesis of casts, reflux nephropathy, and nephritides.

This chapter is an attempt to organize and summarize a diverse literature concerning Tamm-Horsfall uromucoprotein. Importance of examination of urine sediment for casts and diagnostic classification of casts have been discussed. Despite a lack of understanding of its biologic function, clinicopathologic study of T-HM has implicated it as a component of a variety of disease states. It binds a number of proteins, including those on surfaces of bacteria and viruses. It inactivates enzymes of those organisms, possibly by reacting with ionic cofactors, such as divalent metals. Ionic binding of monovalent cations (e.g., Na+) and repulsion of anions, such as Cl-, suggest a role for T-HM in renal salt and water balance. The combination of T-HM with ions, including H+, and other materials that enhance gel formation may indicate an ion-exchange function. Gel (cast) formation in the lower nephron, however, may produce obstruction, which, following calcification, infection, or inflammation, could go on to produce stones, increase scarring, and augment reflux nephropathy. Pathogenetic roles in autoimmunity and disorders of mucus metabolism have also been speculated on.

Adult↗
PubMed1978

Red blood cell casts in acute interstitial nephritis.

A 45-year-old woman receiving hydralazine and hydrochlorothiazide therapy was found to have a reduced glomerular filtration rate, a positive antinuclear antibody reaction, and RBC casts in the urinary sediment. Glomeruli with normal morphology (light, immunofluorescence, electron microscopy) were found on renal biopsy; however, a mild interstitial nephritis was observed that predominantly involved the distal tubules. The etiology of this inflammatory process is unknown. Changes in distal tubular function correlated with the morphology: acidification was impaired whereas concentrating ability was normal. Although RBC casts have been thought to be diagnostic of glomerular diseases, the present case demonstrates that tubulointerstitial disease can be responsible for RBC cast formation.

Acute Disease↗
PubMed1980

Location of the allergenic monomer in warm-polymerized acrylic dentures. Part I: Causes of denture sore mouth, incidence of allergy, different allergens and test methods on suspicion of allergy to denture material - a survey of the literature. Case report, allergenic analysis of denture and test casting.

In the literature dealing with causes of denture sore mouth (D.S.M.) a review is given of some possible allergenic factors in acrylic dentures and of testing procedures, as well as of the incidence of allergy. A report is presented of a patient with D.S.M., the cause of which was allergy to the denture material. Skin tests showed that the surface of the upper denture in contact with the hard palate was allergenic, but not the vestibular surface in contact with the cheeks. The lingual surfaces of the lower denture were not allergenic (the other surfaces were not investigated at this sitting). It could not be ruled out that the resin might be inhomogeneous as regards the allergenic factor. The allergenic properties were verified with test castings in the form of discs made under similar conditions to those for the palatal surface. A test casting made in the same way as the vestibular side of the upper denture showed allergenic properties before polishing. The absence of allergenic properties at this point of the denture could be explained by means of another experiment with a test casting in which the allergenic properties disappeared after polishing of the surface of the resin. The working theory was set up that both the palatal and vestibular surfaces of the denture are allergenic, but that this is eliminated by polishing of the latter. The theory was tested in Part III. It was ruled out that the impression material and insulating material could be allergenic. This study is continued in Parts II and III.

Acrylic Resins↗
PubMed1981

[Studies on Pd-Co-Ni dental casting ferromagnetic alloys. (Part II) (author's transl)].

In the previous paper, the effect of added metals such as Au, Cu, Cr, Si, etc., on the 43 Pd-27 Co-30 Ni alloy was reported. In this paper, the magnetic properties, mechanical properties, corrosion resistance and casting accuracy of the Pd-Co-Ni alloys containing Au, Zn and Si were studied. Results were as follows: 1) Mechanical properties and corrosion resistance of these alloys satisfied the standards for the dental casting alloys. 2) The corrosion resistance of the alloy containing 10 wt% Au was excellent in comparison with other specimens. 3) Casting accuracy was improved by addition of 10 wt% Au-0.1 wt% Si or 10 wt% Au-1 wt% Zn to the base 43 Pd-27 Co-30 Ni alloy.

Chemical Phenomena↗
PubMed1980

SEM of micro-corrosion casts.

The production of micro-corrosion casts suitable for scanning electron microscopy (SEM) is described in this tutorial. The casts are produced by filling an internal luminal system or space with a liquid medium which becomes solid in situ. The surrounding tissue is then removed (corroded) and the resulting replica is dried, rendered conductive, and examined in the SEM. An historical review describes the evolution of the technique and provides perspective for the SEM applications. The criteria which should be fulfilled by the injection medium are listed, and the procedures used for those media which have proven successful, together with their inherent artefacts are described in detail. The two groups of media most commonly used are the rubber compounds and the polymer resins. The latter so faithfully replicate luminal surfaces that a distinction between arteries and veins can be made on the basis of endothelial cell impressions on the surface of the replica. A review of currently used non-SEM techniques provides a comprehensive analysis of the methods used to determine success with SEM micro-corrosion casting, as well as complementary methods for the visualization of vascular and alveolar systems. The paper is illustrated mainly with material from the rat brain vascular system.

Animals↗
PubMed1982

The effects of horizontal body casting on blood volume, drug responsiveness, and +Gz tolerance in the Rhesus monkey.

To simulate the weightless condition, eight rhesus monkeys, instrumented with solid-state pressure transducers, were horizontally restrained in body casts for 28 d. Blood volume decreased an average of 13% after 14 d of restraint, due mainly to a drop in plasma volume. Aortic pressure and heart rate responses to norepinephrine and phenylephrine decreased after 14 d of restraint. The monkeys did not show a statistically significant decreased tolerance to a 90 degree sudden upright tilt after horizontal restraint. During the fifth week of casting, four animals were subjected to +Gz acceleration tests on a centrifuge. The acceleration tolerance of the casted monkeys was significantly reduced compared to four similarly instrumented control animals. These findings indicate that the cardiovascular deconditioning associated with simulated weightlessness results from an inability to maintain central blood volume during orthostatic stress.

Acceleration↗
PubMed1980

Abnormal chest roentgenogram induced by bronchial involvement. --Bronchial cast shadow.

We found rod-like shadows suggesting bronchial involvement in bronchial atresia, allergic bronchopulmonary aspergillosis, bronchiectasis, bronchial stenosis, bronchogenic carcinoma and mucoviscidosis. Typical cases are presented. Various nomenclatures of bronchial involvement based on radiological features or pathological states, such as gloved-finger, tooth-paste shadow, bronchial mucocele and mucoid impaction, are clinically used. We propose "bronchial cast shadow" as an unified term for the roentgenologic diagnosis of these various conditions. The purpose of this paper is; 1) From the radiologic diagnostic stand of view, mucoid impaction of bronchial mucocele is inappropriate, because the same radiologic appearance is not necessarily caused by impacted mucus. In some disorders, the contents of the bronchial lumen might be pus, blood or cells. Initially the abnormal shadow should be described according to the radiologic features, then the pathology of the shadow should be considered. 2) Several different terms are currently used for the same condition. The use of an unified terminology would be convenient for roentgen diagnosis. 3) The recognition of bronchial cast shadow is useful for differential diagnosis of abnormal shadows in the lungs and understanding of abnormal findings. When the bronchial cast shadow is recognized, the underlying cause of it must be determined.

Aspergillosis, Allergic Bronchopulmonary↗
PubMed1994

Reproducibility of occlusal contacts relative to mounting cast variables.

This study evaluated the accuracy of occlusal contacts relative to the mode in which casts are mounted. Specifically, the direct effect on occlusal contacts was assessed with respect to: (a) the type of mounting stone used; (b) the amount of material used relative to the distance between the mounting plate and the cast base; and (c) the presence or absence of a restriction of the articulator's vertical opening. A 3 x 2 x 2 factorial analysis of variance and a Dunn's Multiple Comparison Procedure (P < .05) showed that one of the three mounting stones was statistically significantly less accurate in reproducing occlusal contacts when a distance of 19 mm existed between the cast and the articulator, regardless of the existance of articulator restriction.

Analysis of Variance↗