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Biomedical subjects

Z Kassarjian

Publications and source records attributed to Z Kassarjian.

5 recordsLinked to original sources
PubMed1991

Calcium absorption in elderly subjects on high- and low-fiber diets: effect of gastric acidity.

In vitro studies suggest that the effect of fiber in inhibiting calcium absorption is pH dependent. In nine normal, elderly control subjects and eight elderly subjects with achlorhydria, 47Ca was ingested with three test meals: a low-fiber meal (0.5 g dietary fiber), a high-fiber meal (10.5 g), and a high-fiber meal with 120 mL of 0.1 mol HC/L. In control subjects calcium retention, measured in a whole-body counter, was 25.7 +/- 4.0% (mean +/- SD) with the low-fiber meal, 19.1 +/- 1.9% with the high-fiber meal (P less than 0.002 vs low fiber), and 18.9 +/- 3.3% with the high-fiber-plus-acid meal (P less than 0.002 vs low fiber, NS vs high fiber). Calcium absorption in achlorhydric subjects was not different from control subjects: 26.2 +/- 8.0% with low fiber, 19.6 +/- 4.1% with high fiber (P less than 0.04 vs low fiber), and 21.0 +/- 5.8% with high fiber plus acid (P less than 0.04 vs low fiber, NS vs high fiber). We conclude that, in humans, the reduction in calcium absorption with high fiber intake is unaffected by gastric pH.

Absorption↗
PubMed1989

Effect of age on tests of intestinal and hepatic function in healthy humans.

We studied intestinal function and hepatic microsomal phase I monooxygenase function in healthy, free-living subjects, aged 19-91 yr. In subjects (n = 114) given a diet including 100 g/day of fat, fecal fat in a 72-h collection did not increase with advancing age. D-Xylose excretion (n = 54) following a 25-g oral load significantly declined with increasing age, but a concomitant decline in creatinine clearance suggested a decrease in renal function rather than an absorptive defect. Furthermore, there was no evidence for an age-associated increase in bile salt deconjugation by intestinal bacteria as shown by the glycocholate breath test (n = 60). Finally, there was no evidence for a decrease in hepatic microsomal function with advancing age as measured by the aminopyrine breath test (n = 60). We conclude that digestive/absorptive and hepatic microsomal phase I monooxygenase function are well preserved in healthy humans throughout life.

Adult↗
PubMed1988

Quantitation of the enterohepatic circulation of retinol in the rat.

Studies were done to determine whether vitamin A is reabsorbed in the enterohepatic circulation in forms that can be reutilized by the body for vision and reproduction. Micelles containing [11,12(n)-3H]retinol were administered orally to mesenteric lymph duct-cannulated rats. Lymph containing [3H]retinyl esters and small amounts of [3H]retinol and [3H]retinaldehyde was collected from these rats and an aliquot was injected into the jugular vein of a second group of mesenteric lymph duct-cannulated rats. The total radioactivity recovered in 24-h lymph collections from recipient rats was only 1.6% of that injected, and the [3H]retinyl esters, [3H]retinol and [3H]retinaldehyde recovered was only 0.9% of that injected. Thus, the amount of vitamin A recovered in the enterohepatic route in forms that can be reutilized by the body for vision and reproduction appears to be very small. Notable differences were observed in the composition of mesenteric lymph containing newly absorbed vitamin A and mesenteric lymph containing recycled vitamin A. In the former, 87% of the total lymph radioactivity was associated with retinyl esters, 5% with retinol, 3% with retinaldehyde and 5% with unidentified mostly nonpolar compounds. In the latter, only 41% of the total lymph radioactivity was associated with retinyl esters, 12% with retinol, 3% with retinaldehyde and 44% with unidentified mostly polar compounds.

Absorption↗
PubMed1988

Enterohepatic circulation of newly administered alpha-tocopherol in the rat.

We have measured the magnitude of the enterohepatic circulation of newly administered [3H]-alpha-tocopherol in rats. One group of animals (day-1 rats) was used to prepare [3H]-alpha-tocopherol-containing lymph. Another set of animals (day-2 rats) was divided into control and vitamin E supplemented (+E) groups, which were used to study the enterohepatic circulation of [3H]-alpha-tocopherol from day-1 rat lymph administered into the jugular vein of day-2 rats. Mesenteric lymph duct and common bile duct cannulations were performed. The enterohepatic circulation in day-2 rats of intrajugularly administered [3H]-alpha-tocopherol in chylomicrons was found to be 1.78 +/- 0.23% for control and 0.98 +/- 0.08% for +E rats (p less than 0.01). A considerable quantity (13.3 +/- 4.3% in control vs 19.2 +/- 4.7% in +E) of [3H]-radioactivity was recovered in bile over 24 h, of which pure [3H]-alpha-tocopherol was 3.17% in control and 1.04% in +E bile. More than 95% of [3H]-radioactivity recovered in day-2 control and +E bile was more polar than alpha-tocopherol shown by high performance liquid chromatography (HPLC). In contrast, more than 95% of [3H]-radioactivity appearing in day-2 lymph was unchanged alpha-tocopherol. Thus, the magnitude of enterohepatic circulation of alpha-tocopherol is very small in rats. Quantitation of the enterohepatic circulation of vitamin E under different physiological conditions remains to be investigated.

Animals↗