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Biomedical subjects

L Friedman

Publications and source records attributed to L Friedman.

At least 271 records · Page 15Linked to original sources
PubMed1980

The barren prospect of a representation world.

This is a criticism of the view that the term "representation" has a peculiarly tangible clinical referent, a unique phenomeriological meaning, and a special power to reveal subjective reality undistorted by theoretical constructs. Such a view is illegitimately encouraged by a tendency to think of "image" when we say "representation", even though we mean something more like "understanding", and by a tendency to treat understanding as though they were discrete experiences of the subject, rather than abstractions made by the observer. Because the reliance on representational terms mixed method with data, its covert principles of abstraction cannot be used to learn from new data.

Freudian Theory↗
PubMed1980

Kohut: a book review essay.

Kohut's homeostatic account of mental events in terms of their self-preservative function may be a compromise between a theory of affective markers of psychic differentiation and a theory of self-esteem drives. Similarly, an appreciative style of treatment, designed to keep the analyst available for the exercise of growth needs, is supplemented by the interpretive task of integrating incongruent tendencies. Kohut's work raises interesting questions about theoretical circularity, freedom from a single set of conceptual principles, the value of en bloc histories of affective constellations, and the consequences of a treatment at once exculpatory and judgmental.

Adult↗
PubMed1980

In vivo and in vitro metabolism of [14C]penicillic acid.

In vivo and in vitro studies of the metabolism of [14C]penicillic acid showed a significant uptake of penicillic acid by red blood cells and a significant increase in radioactivity associated with the membrane fraction with time (1-4 hr); however, the majority of the red blood cell activity was intracellular. The 14C-radioactivity concentration in liver fractions (1.5 percent of the administered dose 2 hr following administration) was high in the RNA-DNA and protein fractions. The level of the 14C activity associated with these fractions increased with time (24 hr). Preliminary studies of the in vivo metabolism of [14C]penicillic acid by rats showed that a significant amount of radioactivity was excreted in the urine (82 percent of the administered dose after 7 days), of which strongly acidic urinary metabolites accounted for 23 percent; weakly to moderately acidic, 60 percent; strongly basic, 2 percent; and neutral, 15 percent. Isolation and identification studies of the neutral urinary fraction indicated that the major metabolites are non-ionic macromolecules (Mr < 5000). Biliary metabolites (10 percent of the administered dose 2 hr following administration) were 28 percent strongly acidic and 72 percent weakly to moderately acidic.

Absorption↗
PubMed1979

Mass-spectral identification and purification of phycoerythrobilin and phycocyanobilin.

The bile-pigment chromophores of C-phycoerythrin (phycoerythrobilin) and C-phycocyanin (phycocyanobilin) were cleaved from their respective proteins with boiling methanol or butan-1-ol. They were purified as dicarboxylic acids by preparative reverse-phase liquid chromatography. Each pigment existed in two principal forms, which were characterized by using 20 pmol samples by proton-transfer chemical-ionization mass spectroscopy. These two principal forms were isomeric species, and all had protonated parent molecular ions with m/e 587, corresponding to a molecular weight of 586.

Chemical Phenomena↗
PubMed1979

Effects of sleep deprivation on sleepiness, sleep intensity, and subsequent sleep in the rat.

The effects of 24 hr of sleep deprivation on cortical EEG and ventral hippocampus EEG recordings, ventral hippocampus spike rates, sleep stages percentages, and bout length measures were studied in rats. Two groups, differing only in the rate and distance they were forced to walk during deprivation by the water wheel method, were recorded continuously (23 hr per day) for one baseline, one deprivation, and two recovery days. During deprivation, microsleeps, increased hippocampal spike rates, and increased amplitude of the EEG recordings all suggested the intrusion of sleep processes. Nonetheless, there was no evidence to support the idea that these animals were not substantially deprived of sleep. No important differences were found in the recovery data of the two groups, even though one group walked three times as far as the other during deprivation. This supports the idea that, in conjunction with large amounts of sleep deprivation, changes in exercise and energy depletion may have little effect on sleep measures. During recovery, increased hippocampal spike rates and bout lengths, as well as increases in EEG amplitude, were interpreted in terms of increased sleep "intensity." High amplitude NREM sleep rebounded first, followed by rebounds in both paradoxical sleep and low amplitude NREM sleep. This pattern was compared to patterns previously reported for humans, cats, and rats. Finally, the tendency for some measures to fall below their baseline levels after an initial rebound was discussed in terms of "sleep inhibition" and servomechanism theory.

Animals↗
PubMed1979

Approaches to the formulation of standards for carcinogenic substances in the environment.

After having agreed that standards are necessary for carcinogens that cannot be completely eliminated from the environment, two exchange groups in the U.S.S.R.-U.S. Cooperative present their different approaches to the problem. The Russian groups has recommended a benzypyrene standard of 0.1 microgram/100m3 of atmospheric air over populated regions and gives its experimental basis and theoretical rationale in the first part of this joint paper. Lifetime experiments in adult rats over a wide range of dose levels permit the determination of a largest ineffective dose level with respect the theoretical time of first tumor as well as incidence. The standard is set by extrapolation based on body weight and uses a safety factor of 10 to account for the additional susceptibility in embryogenesis and childhood. The U. S. group presents a mathematical model of time-to-tumor occurrence which permits the prediction of population incidence and life span shortening from time-to-tumor data in animals or man. It assumes the distribution of mortality-corrected time to tumor is lognormal with the nth power of time inversely proportional to dose and with dose independence of the variability of the logarithm of time to tumor. The prediction is made by combining this distribution, fitted to the data, with population mortality tables. Both groups emphasize that substantial research efforts are necessary to improve the scientific basis for setting standards.

Animals↗
PubMed1978

Factors influencing the incidence of neonatal jaundice.

A retrospective study of 12 461 single births confirmed an association between maternal oxytocin infusion and neonatal jaundice. The effect of oxytocin on jaundice was independent of gestational age at birth, sex, race, epidural anaesthesia, method of delivery, and birth weight, each of which was significantly associated with neonatal jaundice. The effect of oxytocin was, however, small, producing a calculated mean increase in peak plasma bilirubin concentration of 8.6 mumol/1 (0.5 mg/100 ml); this excess was independent of sex and less than the effect of the baby being born one week earlier.

Bilirubin↗
PubMed1978

Natural 13C/12C ratio variations in human populations.

Baseline data on the naturally occurring 13C/12C ratios of human tissue samples from several modern human populations are presented. Isotope ratios were determined for endogenous tissue samples (brain, liver and lung) from 20 routine unselected autopsy cases of residents of Long Island, New York. Comparable data were obtained from tissue samples from Bergen, Norway and Lucerne, Switzerland. Average values of 13C ratios reported in units of delta13C(0/00) relative to the PDB carbonate standard were -20.6 +/- 1.0 for 49 tissue samples from Switzerland, -20.7 +/- 1.0 for 21 tissue samples from Bergen, Norway and -16.2 +/- 1.0 for 89 tissue samples from Long Island, New York. These variations are discussed in terms of the isotopic carbon inventory in the respective diets of the populations sampled and also in terms of their implications for biomedical investigation.

Autopsy↗
PubMed1978

The 13C/12C ratio in black pulmonary pigment: a mass spectrometric study.

Ratios of the two stable isotopes of carbon, 13C and 12C, were measured in black pulmonary pigment and in several endogenous tissues removed during 20 autopsies on Long Island, New York. The mass spectrometer used for carbon isotope ratio analyses has a precision of +/- 1 13C atom per million carbon atoms. The 13C/12C ratio was found to be distinctly lower in black pulmonary pigment than in endogenous tissues, the mean difference amounting to 65 13C atoms per million carbon atoms. The results demonstrate that the elemental carbon fraction of black pulmonary pigment is exogenous and constitutes roughly 30 per cent of the weight of the pigmented material. It was also observed that 13C/12C ratios in endogenous tissues from individual autopsy cases were not quite identical, tending to be slightly greater in corpus callosum than in liver or peripheral lung.

Aged↗