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Biomedical subjects

L Page

Publications and source records attributed to L Page.

At least 55 records · Page 3Linked to original sources
PubMed1986

The catabolism of plasmenylcholine in the guinea pig heart.

The hydrolysis of the alkenyl bonds of plasmenylcholine and plasmenylethanolamine by plasmalogenase, followed by hydrolysis of the resultant lysophospholipid by lysophospholipase, has been postulated as the major pathway for the catabolism of these plasmalogens. However, the postulation was based solely on the presence of plasmalogenase activity towards plasmenylethanolamine and plasmenylcholine in the brain. In this study we have demonstrated the absence of plasmalogenase activity for plasmenylcholine in the guinea pig heart under a wide range of experimental conditions. Plasmenylcholine was hydrolysed by phospolipase A2 activities in cardiac microsomal, mitochondrial and cytosolic fractions. Phospholipase A2 activities in these fractions had an alkaline pH optimum and were enhanced by Ca2+. The enzymes also displayed high specificity for plasmenylcholine with linoleoyl or oleoyl at the C-2 position. Lysoplasmalogenase activity for lysoplasmenycholine was also detected and characterized in the microsomal and mitochondrial fractions. Since the cardiac plasmalogenase is only active towards plasmenylethanolamine but not plasmenylcholine, the catabolism of these two plasmalogens must be different from each other. We postulate that the major pathway for the catabolism of plasmenycholine involves the hydrolysis of the C-2 fatty acid by phospholipase A2, and hydrolysis of the vinyl ether group of the resultant lysoplasmenylcholine by lysoplasmalogenase.

Animals↗
PubMed1986

Spinal cord tumors presenting with neural tube defects.

Two primary lumbosacral tumors arising at the site of neural tube defects are presented. One was a teratoma diagnosed in an infant with myelomeningocele. The other was an ependymoma that developed in an adult with meningocele. It is postulated that these cases represent a neoplastic transformation of heterotopic primordial elements that have been incorporated within the defect, supporting the view that overgrowth of neural tissue may be the result rather than the cause of neural tube deformity. Such rare occurrences may be due to interaction between intrauterine teratogenic factors and familial predisposition in affected patients.

Adult↗
PubMed1985

Normal values for trabecular and cortical bone in the radius measured by computed tomography.

Quantities related to the amount of trabecular bone in the distal radius and cortical bone in the radius mid-shaft have been measured in 262 normal adults of both sexes aged 21-89 years by computed tomography (CT). A special-purpose CT system (ISOTOM) which incorporated a source of 125I (29 keV) was used to make the measurements. The relationships between these quantities and age, weight, height and surface area have been evaluated, and the results have been used to draw conclusions on the significance of values measured in female patients with osteoporosis, Colles' fracture of the wrist and generalised osteoarthritis.

Absorption↗
PubMed1984

Decreased radial bone mass in Colles' fracture.

Computed tomography measurements on the radii of 18 women with Colles' fracture of the radius have shown that compared to normal women of the same age they tended to have a smaller bone cross-sectional area in the radius midshaft, a small deficit of cortical bone, and a substantial deficit of trabecular bone in the distal radius.

Age Factors↗
PubMed1983

Cytologic and molecular analysis of 46,XXq- cells to identify a DNA segment that might serve as a probe for a putative human X chromosome inactivation center.

Cloned human X chromosome-specific DNA segments, derived from a recombinant phage library enriched for the human X and previously localized to different regions of the X, were used as probes in Southern blots to confirm the nature of a deletion of the long arm of the X chromosome as del(X)(q13) in a patient with some features of Turner's syndrome and suspected from cytologic studies to have a 46,XXq- karyotype. Two dimensional scanning densitometry of autoradiograms of the Southern blots was used to quantitate hybridization of the 32P-labeled probes, reinforcing visual analysis and permitting distinction between sequences present at one or two copies per diploid genome. Once thus characterized, DNA from the patient's cells was used in quantitatively analyzed Southern blots to refine the location of an additional DNA segment, previously mapped to somewhere in the proximal part of the long arm of the X chromosome, to the juxtacentromeric region of Xq, which has been hypothesized to be critical for X-inactivation. Cloned DNA probes such as that localized to the juxtacentromeric region of Xq should be useful for evaluating this hypothesis.

Absorptiometry, Photon↗
PubMed1977

Nutritive content of college meals. III. Mineral elements.

Two samples, each consisting of two breakfasts, two lunches, and two dinners as offered to college students, were collected for seven consecutive days from each fifty colleges. The composited meals for each college were analyzed for five major mineral elements--calcium, phosphorus, magnesium, sodium, and potassium--and five trace mineral elements--iron, chromium, copper, manganese, and zinc. On a per-person-per-day basis, the meals met or exceeded the recommended dietary allowances for nineteen-to-twenty-two-year-old men and women for calcium and phosphorus. Meals from most of the colleges were below the allowance for magnesium, over nine-tenths were short in zinc, and about three-fifths were below the allowance for iron for females but in only one college for males. Average ratios for mineral element to mineral element are reported.

Adolescent↗
PubMed1976

Nutritive content of college meals. II. Lipids.

Two samples, each consisting of two breakfasts, two lunches, and two dinners as offered to college students, were collected for seven consecutive days from each of fifty colleges. Two samples of the composited meals from each college were analyzed for fat and fatty acids. The fat content of the meals averaged 125.58 gm., with a range of 96.96 to 163.74 gm. This provided an average of 42.33 per cent of total calories, (range, 36.68 to 47.67 per cent). No college served meals with as little as 35 per cent of calories derived from fat. The meals contained an average of 46.3 gm. saturated fatty acids; 48.98 gm. mono-unsaturated fatty acids, of which 48.19 gm. were oleic acid; and 18.25 gm. polyunsaturated fatty acids, of which 17.22 gm. were linoleic acid. Four fatty acids--palmitic (C-16); stearic (C-18); oleic (C-18:1); and linoleic (C-18:2)--contributed approximately 92 per cent of the total fatty acids. The average ratio of polyunsaturated fatty acids to saturated fatty acids was 0.39 (range, 0.22 to 0.69). Six colleges served meals with a P:S ratio of 0.30 or below; five colleges had a P:S ratio of 0.50 or above.

Diet↗
PubMed1975

Nutritive content of college meals. Proximate composition and vitamins.

Two samples, each consisting of menus of two breakfasts, lunches, and dinners, as offered to college students, were collected for seven consecutive days from each of fifty colleges. The composited meals were analyzed to determine proximate composition and content of vitamin A, vitamin D, thiamin, riboflavin, niacin, folacin, vitamin B6, and vitamin B12. On a per-person-per-day basis, the meals met or exceeded the Recommended Dietary Allowances for nineteen-to-twenty-two-year-old men and women for protein, vitamin A, riboflavin, and niacin. About a third of the meals were below the allowances for vitamin D, three-fifths were short in thiamin, and three-fourths were short in folacin and vitamin B6. A number of colleges offered meals that were short on calories.

Adolescent↗