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Biomedical subjects

M Novak

Publications and source records attributed to M Novak.

At least 145 records · Page 8Linked to original sources
PubMed1983

Natural abundance 13C nuclear magnetic resonance studies of live cestodes.

1. Natural abundance carbon-13 nmr spectra of several intact cestodes have been obtained. 2. All spectra show peaks assignable to triglycerides and the N(CH3)3 carbons of the choline moiety. 3. The olefinic region of the 13C nmr spectra indicated that the cestode larvae Mesocestoides corti and Echinococcus multilocularis have a larger concentration of polyunsaturated fatty acids than Hymenolepis adults. 4. Mobile fragments of glycogen were detected in all species studied, but its apparent concentration in individual cestodes was highly variable.

Alkenes↗
PubMed1983

Discovering a good age.

In the past, gerontologists often used sick or institutionalized people in their research. As a result, aging came to be seen as a time of decline filled with problems. Even today some of the best research dwells on the problems that come with age. To balance this view, in a recent study I spoke with over sixty of the "best" older people I could find. These were people who exemplified a good age--they were healthy, happy, active, involved and eager to tell about their lives. From their comments, it appears that a good age does not happen by accident. It is something people work for and discover for themselves; a process described in this paper.

Adaptation, Psychological↗
PubMed1981

Carnitine in the perinatal metabolism of lipids. I. Relationship between maternal and fetal plasma levels of carnitine and acylcarnitines.

Since premature infants have a limited capacity for fatty acid oxidation, supplementation with carnitine may improve their utilization of fat. Documentation of the source and extent of fetal carnitine reserves should explain the possible need for exogenous carnitine in the neonate. Correlation between free carnitine concentration in maternal and umbilical arterial plasma at birth (r = .45, P less than .01) indicates that the initial concentration of free carnitine in the newborn depends on the maternal level. Thin-layer chromatography shows more gamma-butyrobetaine in maternal than umbilical arterial plasma indicating higher availability of the precursor of carnitine biosynthesis. Elevated fatty acid oxidation in maternal tissues seems to be reflected by larger amounts of long-chain acylcarnitines in maternal plasma. Short-chain acylcarnitines, mainly acetylcarnitine, are higher in the umbilical vein than in maternal plasma (P less than .01) indicating that the conceptus (the placenta or fetus) is either producing more or utilizing less acetylcarnitine. Plasma levels of carnitine rapidly decrease in premature newborns during the first three days after birth if no exogenous carnitine is given (P less than .001), while no significant changes of total carnitine were detected in adult patients on total parenteral alimentation for one week. This difference indicates lower carnitine depots or limited capacity for carnitine biosynthesis in neonates. The possibility still requires further investigation that the development of the optimal rate of fatty acid oxidation in human newborns, as well as in other newborn mammals, may depend on the supply of exogenous carnitine.

Carnitine↗
PubMed1981

Labeling of preformed liposomes with Ga-67 and Tc-99m by chelation.

We have synthesized a long-chain hydrocarbon covalently coupled to diethylene-triaminepenta-acetic acid (stearylamine-DTPA) and have incorporated this compound in liposomes during their preparation. The lipophilic hydrocarbon chain anchors the molecule in the lipid bilayer, exposing the DTPA groups on the surface for chelation. Ethanolic solutions of the lipids are evaporated to dryness under nitrogen in multidose vials; the lipids are suspended in the vial by adding a small volume of distilled water followed by sonication. The liposomes are then labeled by transcomplexation in the case of Ga-67 and by conventional stannous reduction in the case of Tc-99m, by adding the activities directly to the vial. These liposomes bind 95 +/- 5% of Ga-67 and Tc-99m activity, as determined by paper chromatograph assay, eliminating the need for a purification step. The labeled liposomes release about 5% of their Ga-67 activity, and about 30% of their Tc-99m activity after 2 hr of incubation in 50% human plasma at 37 degrees C. Activity released from liposomes labeled with Ga-67 or Tc-99m oxine is much greater under the same conditions. In normal mice the labeled liposomes show biodistributions that are comparable with that obtained with liposomes labeled by conventional techniques.

Amines↗