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Biomedical subjects

D S Lin

Publications and source records attributed to D S Lin.

At least 91 records · Page 5Linked to original sources
PubMed1983

Comparative lymphatic absorption of sitosterol, stigmasterol, and fucosterol and differential inhibition of cholesterol absorption.

Studies have been conducted on the lymphatic absorption of sitosterol (24 alpha-ethyl cholesterol), stigmasterol (delta 22, 24 alpha-ethyl cholesterol), and fucosterol (24-ethylidine cholesterol) when administered intragastrically to rats. In addition, the effect of each sterol on absorption of endogenous cholesterol has been assessed by including tracer cholesterol in the administered test emulsion. Analysis of 24-h lymph collections by GLC-mass spectrometry demonstrated that all three sterols were poorly absorbed to the extent of only 3 to 4% of the administered dose of 50 mg. In contrast, cholesterol absorption under similar conditions was about 42% of the administered dose. Administration of either sitosterol or stigmasterol resulted in an equally effective inhibition of cholesterol absorption (54%). Under identical conditions fucosterol had no effect on absorption of luminal cholesterol. The data suggest that the mechanism(s) for intestinal discrimination of sterols for absorption may be independent of the mechanism for interference with efficient cholesterol uptake by the intestine.

Absorption↗
PubMed1983

"Hot" spleen on Tc-99m sulfur colloid images.

In routine Tc-99m sulfur colloid (SC) liver-spleen imaging, relatively increased splenic uptake when compared with liver uptake is frequently seen. Commonly this is due to decreased hepatic uptake secondary to liver disease, but often it is because of increased uptake in the hyperfunctioning spleen. Reported is a case of lymphoma of the tonsil, with a "hot" spleen which was free of tumor. Possible etiology of the "hot" spleen is discussed and the known causes listed according to their prevalence.

Adult↗
PubMed1983

Ga-67 cardiac uptake.

A case of positive Ga-67 image due to tuberculous pericarditis is presented. The pattern and distribution of the uptake suggested that the concentration of the activity was mainly in the inflamed pericardium. The known causes of Ga-67 cardiac uptake were reviewed, and a differential diagnosis is given.

Adult↗
PubMed1983

The origin of plant sterols in the skin surface lipids in humans: from diet to plasma to skin.

To test the hypothesis that plant sterols found in the skin surface lipids of humans originated from diet after their absorption from intestine into plasma and then transferred to skin, we studied the 24-h excretion of plant sterols and cholesterol from skin and in feces in a hyperlipoproteinemic (type IIa) patient fed formula diets providing varying quantities of plant sterols (0-30 g/day) and cholesterol (0-1000 g/day). Upon feeding a sterol-free diet, the beta-sitosterol excretion from the skin decreased progressively, from about 6 mg/day to 0.08 mg/day by 83 days and then completely disappeared. With addition of plant sterols (about 30 g/day) to the diet, beta-sitosterol reappeared in the skin surface lipids and rose to nearly 5 mg/day by 6 weeks. With feeding of the sterol-free diet, the fecal excretion of beta-sitosterol and the 2 other plant sterols decreased gradually and by week 4 disappeared completely from the feces and continued to be absent from the feces as long as the diet was free of plant sterols. The results demonstrated clearly that plant sterols which were absorbed into the plasma from the diet were excreted into the skin surface lipids after being transferred from the plasma to the skin.

Cholesterol↗
PubMed1983

Delayed renal localization of Ga-67: concise communication.

Five hundred Ga-67 images, requested for detection or follow-up of inflammatory or neoplastic diseases, were reviewed to evaluate the incidence of delayed renal localization and the clinical significance of different degrees of uptake. Renal uptake in 48- or 72-hr images was graded as follows: 0 = background activity; 1+ = greater than background but less than spine; 2+ = close to spine but less than liver; 3+ = same as liver; 4+ = greater than liver. On the 500 images, 996 kidneys were evaluated and among them 600 (60%) had 0 uptake and 340 (34%) had 1+. These 940 kidneys were all considered to be normal. Fifty-six (6%) had 2+ or more uptake, with possible causes for uptake being: infection 27, drug-induced renal damage ten, urinary stasis or slow excretion seven, collagen vascular disease six, renal failure four, acute tubular necrosis one (ATN), and indeterminate one. Cases of renal infection or failure tended to show more or less 4+ uptake, while drug damage, ATN, or urinary stasis tended to have 2+ uptake.

Adolescent↗
PubMed1983

Lipids of human atherosclerotic plaques and xanthomas: clues to the mechanism of plaque progression.

While the content of fatty streaks and fibrous plaques has been extensively studied in autopsied specimens, little is known about the lipid composition of advanced human atherosclerotic plaques requiring surgical removal. We have analyzed free cholesterol, cholesteryl ester, and the cholesteryl ester fatty acid content in 19 carotid and 7 femoral obliterative plaques obtained at endarterectomy. These were compared with values from each subject's plasma and from xanthomas removed from eight patients. The total cholesterol content was 75.1 mg/g dry weight for carotid plaques, 56.0 mg/g for femoral plaques, and 106.8 mg/g for xanthomas. The free cholesterol content was 56.6% and 50.4% of the total cholesterol for carotid and femoral plaques, respectively, while the free cholesterol of xanthomas was only 25.5%. The fatty acids of cholesteryl esters were analyzed in an attempt to identify the site of their esterification, i.e., within plasma or within plaque. This can be determined using the ratio of linoleic acid (18:2) to oleic acid (18:1) in the cholesteryl ester. The ratios were 0.36 for xanthoma, 1.62 for carotid plaque, 1.73 for femoral plaque, and 2.51 in plasma. These data emphasize two chemical changes occurring with evolution of the atherosclerotic process: 1) The cholesteryl ester fatty acid composition of the plaque becomes increasingly similar to that of plasma, and 2) there is a continuing increase in the percentage of free cholesterol. These alterations reflect a decreased metabolic efficiency within atherosclerotic lesions and may initiate events that enhance plaque progression.

Arteriosclerosis↗
PubMed1982

The effect of shellfish in the diet upon the plasma lipid levels in humans.

In order to document any hypercholesterolemic effects from the ingestion of shellfish, 6 normal men were given two diets containing different shellfish, each preceded by a low cholesterol baseline diet. Diet I contained 449 mg cholesterol per day from lobster, crab, and shrimp. Diet II contained clam, oyster, and scallop and provided 447 mg of sterols of which cholesterol constituted only 40 percent. The other sterols are uniquely characteristic of these shellfish (i.e. brassicasterol, 24-methylene cholesterol, etc.). In a second study, 2 normal men and 1 type II hypercholesterolemic woman were fed the baseline diet and shellfish diet II to provide 623 mg of sterols per day. The plasma cholesterol of the 6 subjects averaged 184 +/- 35 mg/dl during baseline, 192 +/- 35 mg/dl in shellfish diet I (p less than 0.05) and 182 +/- 24 mg/dl during shellfish diet II. In the second study, the plasma cholesterol of the 2 normal men did not change. The cholesterol of the hypercholesterolemic woman increased from 311 mg/dl (baseline) to 352 during the shellfish diet (p less than 0.05). Plasma triglyceride levels remained unchanged. Our data indicated that large quantities of lobster, crab, and shrimp were only mildly hypercholesterolemic in normals, but less so than other cholesterol-containing foods. Clams, oysters, and scallops were not hypercholesterolemic in normal subjects but were in a hypercholesterolemic patient.

Adult↗
PubMed1981

Lymphatic absorption of shellfish sterols and their effects on cholesterol absorption.

Studies have been conducted on the absorbability of individual sterols from a mixture of oyster sterols when administered intragastrically to rats with indwelling catheters in the left thoracic duct. In addition, the effect of oyster sterols on cholesterol absorption has been assessed using [4-14C] cholesterol in the mixture, and comparison against absorption of cholesterol alone. The order of absorbability (percentage absorption) of individual sterols from the mixture of oyster sterols was: cholesterol greater than or equal to 26-carbon sterols greater than or equal to dehydrocholesterol greater than 24-methylene cholesterol greater than brassicasterol greater than plant sterols. The absorption of noncholesterol sterols was 8.2 +/- 0.8% of the fed dose, or less than half of that for an equivalent level of cholesterol alone. The presence of these sterols in mixtures containing cholesterol reduced lymphatic absorption of cholesterol by 25 to 40% compared to absorption of the same amount of cholesterol administered alone, or to an amount of cholesterol equal to the total oyster sterols, respectively. These studies suggest that shellfish sterols are poorly absorbed, and, like plant sterols, effectively reduce dietary and/or endogenous cholesterol absorption from the intestine.

Absorption↗