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Biomedical subjects

R Yu

Publications and source records attributed to R Yu.

At least 181 records · Page 10Linked to original sources
PubMed1984

Thalidomide-induced peripheral neuropathy. Effect of serum factor on nerve cultures.

Sensory neuropathies developed in three of four patients with prurigo nodularis who had been treated with thalidomide. The serum samples of the patients who had neuropathy produced morphologic changes in cultured dorsal root ganglion cells. These observed changes support the postulate that thalidomide induces primary neuronal degeneration.

Adult↗
PubMed1984

Vascular studies in the preoperative evaluation of pituitary adenomas before transsphenoidal surgery.

The transsphenoidal approach is being increasingly utilized in the surgical treatment of pituitary microadenoma. Even with high-resolution and dynamic computed tomography (CT) scanning, subtle vascular anatomic variants and other vascular anomalies involving the parasellar carotid arteries cannot always be clearly defined. Five cases are described in which evaluation by digital intravenous subtraction angiography or standard carotid arteriography provided useful preoperative information before transsphenoidal surgery. The implications of these findings are discussed.

Adenoma↗
PubMed1984

Role of computed tomography in symptomatic vertebral hemangiomas.

Vertebral hemangioma, although a benign lesion, can result in neurologic deficit. Computed tomography is useful in demonstrating the extension of the hemangioma into the posterior neural arch and epidural space. Computed tomography after intravenous contrast administration is useful in evaluating the vascular nature of the lesion and is a useful technique before surgery or spinal angiography.

Female↗
PubMed1983

Cigarette staining and cleaning of a maxillofacial silicone.

In this study, a maxillofacial silicone elastomer was stained with cigarette smoke. The stain was then removed by solvent extraction using 1,1,1-trichloroethane. The cigarette smoke produced large color changes in the elastomer as measured from spectrophotometric reflectance curves. The solvent was totally effective in removing the cigarette stain without changing the color of the silicone base.

Color↗
PubMed1982

Response of patients with amyotrophic lateral sclerosis to testosterone therapy: endocrine evaluation.

Four men with amyotrophic lateral sclerosis (ALS) were treated with 200 mg of intramuscular testosterone weekly. Endocrine evaluation, using a gonadotropin-releasing hormone infusion test, indicated the expected degree of suppression of pituitary luteinizing hormone and follicle-stimulating hormone production. These data suggest that testosterone's (androgen) interaction with its receptors in the hypothalamic-pituitary axis is normal in patients with ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1982

Stain removal from a pigmented silicone maxillofacial elastomer.

The removal of environmental stains from a pigmented maxillofacial elastomer was carried out by solvent extraction under network swelling. Silastic 44210 was pigmented with 11 maxillofacial pigments prior to staining. Samples were stained with lipstick, methylene blue, and disclosing solution. These stains were then removed by solvent extraction with 1,1,1-trichloroethane. Color parameter measurements both before and after staining and after solvent extraction demonstrated the effectiveness of removing these stains by solvent extraction while causing little or no change in the color of the pigmented samples.

Color↗
PubMed1981

Reflection spectrophotometry of facial skin.

The color of human skin of 241 whites, blacks, and orientals was measured by reflection spectrophotometry. Among these groups, major differences in luminous reflectance and excitation purity, but not in dominant wavelength, were observed. The twin absorption bands of oxyhemoglobin at 540 and 580 nm were more prominent in whites (particularly females) than in orientals or blacks. Parameters determined for Source A were higher than those for Source C.

Asian People↗
PubMed1981

Translucency of human dental enamel.

Translucency of human dental enamel was determined by total transmittance of wavelengths from 400 to 700 nm. The transmission coefficient at 525 nm was 0.481 mm-1. Total transmission of light through human dental enamel increased with increasing wavelength. Human tooth enamel is more translucent at higher wavelengths. The translucency of wet human enamel and enamel after dehydration was also measured by total transmittance. The transmission coefficient at 525 nm decreased from 0.482 to 0.313 mm-1 after dehydration and was reversed on rehydration. The decrease in translucency occurred as a result of the replacement of water around the enamel prisms by air during dehydration.

Color↗
PubMed1981

Stain removal from a silicone maxillofacial elastomer.

In this study, environmental stains were removed from maxillofacial elastomers by solvent extraction. Silastic 44210, an RTV silicone with proven color and physical property stability, was stained with lipstick, disclosing solution, and methylene blue. These stains were then removed by solvent extraction with each of four chemically dissimilar solvents, namely: toluene, benzene, 1,1,1-trichloroethane, and n-hexane. An additional series of samples was prepared with 11 maxillofacial pigments, not for staining, but for evaluation of pigment stability. Results obtained from spectrophotometric measurements before and after solvent extraction demonstrated the effectiveness of solvent extraction in removing stains, while there was little or no change in the color of the pigments or the base elastomer.

Chemical Phenomena↗
PubMed1980

Properties of silicone maxillofacial elastomer processed in stone and metal.

1. The effect of mold conditions on the UTS, n, and TS at 200% and 300% elongations, and Shore A hardness was measured for Silastic 44210. 2. There was no difference in n, Shore A hardness, and TS at 200% and 300% elongation between Silastic 44210 samples whether produced in metal or coated stone molds. 3. The highest UTS for Silastic 44210 was demonstrated for samples processed in aluminum molds. The UTS was slightly reduced when coated stone molds were used, and it was considerably reduced with untreated stone molds. It is felt that the slight decrease in UTS with coated stone molds would not compromise the use of stone molds clinically, particularly when ease of processing is considered. 4. Petroleum jelly, silicone spray, and tinfoil substitute were all equally effective in improving the physical properties of the elastomer when processed in a stone mold. These results demonstrate the necessity of using a mold sealant when processing Silastic 44210 in a stone mold.

Aluminum↗
PubMed1980

Physical properties of maxillofacial elastomers under conditions of accelerated aging.

The stability of the physical properties of various commercially available maxillofacial prosthetic materials was evaluated with the use of an accelerated aging chamber. The tensile strength, maximum percent elongation, shear strength, tear energy, and Shore A hardness were determined before and after accelerated aging. Results indicate that silicone 44210, a RTV rubber, is a promising elastomer for maxillofacial application.

Chemical Phenomena↗
PubMed1980

Physical properties of a pigmented silicone maxillofacial material as a function of accelerated aging.

The effects of accelerated aging on a pigmented elastomer were evaluated by using a weathering chamber. Silastic 44210, a maxillofacial material with proven color and physical property stability, was chosen for pigmentation with 11 maxillofacial pigments. The values of ultimate tensile strength, maximum percent elongation, shear strength, Shore A hardness, and permanent deformation were determined for the pigmented elastomer before and after accelerated aging for 900 h. Results obtained indicate that the incorporation of 0.2% by weight of pigments can alter the physical and mechanical properties of the base elastomer. Accelerated aging had no effect on the physical properties of the pigment/elastomer combinations.

Chemical Phenomena↗