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Biomedical subjects

L Friedman

Publications and source records attributed to L Friedman.

At least 217 records · Page 12Linked to original sources
PubMed1988

Comparative study of the abuse liability of alprazolam, lorazepam, diazepam, methaqualone, and placebo.

Subjective effects of two benzodiazepines--alprazolam and lorazepam--were compared with two drugs of known abuse potential--diazepam and methaqualone--and placebo. This double-blind, crossover trial tested 30 casual recreational sedative users in a seminaturalistic setting. Methaqualone was more euphoriant and less sedative than the benzodiazepines. Diazepam and lorazepam were more euphoriant than placebo; alprazolam's euphoriant effect did not differ from these treatments. On other measures of abuse liability the benzodiazepines rated similarly, diazepam rating highest.

Adolescent↗
PubMed1988

The 30 degree cephalad anteroposterior tilt view to stage avascular necrosis of the femoral head.

A 30 degree cephalad anteroposterior tilt view of the femoral head was used, in addition to standard radiographic projections, in 55 patients having, or suspected of having, avascular necrosis of the femoral head. This method was then compared with standard views. Five patients with questionable findings on standard projections showed definite avascular necrosis, and 10 thought on standard views to have grade 2 disease were found to be grade 3, all from use of the additional projection. This projection should form part of the evaluation of suspected avascular necrosis of the femoral head.

Femur Head Necrosis↗
PubMed1988

The clinical popularity of object relations concepts.

Object relations theory has the effect of supporting the psychoanalyst when he feels that the patient's effort is strongly opposed to his own. The current popularity of object relations theory may be related to the gradual disappearance from Freudian theory of a simple, clear image of an obligatory insistence by the patient that is useful even though it is unreflective. Object relations theory offers the practitioner a way of fortifying himself against blind demand, while newer Freudian theorists cope with the problem by orienting themselves more stringently toward the original paradigm of optional choice.

Freudian Theory↗
PubMed1987

The toxicity of MPTP to dopamine neurons in culture is reduced at high concentrations.

The toxicity of MPTP to dopamine (DA) neurons was studied in dissociated cell cultures from rat embryo mesencephalon. The cultures were exposed to MPTP (from 0.1 to 200 microM) for 7 days and were analyzed by catecholamine histofluorescence after incubation with alpha-methylnorepinephrine, by tyrosine hydroxylase (T-OH) immunocytochemistry and by [3H]DA uptake. Treatment with MPTP at the lower range of concentrations (between 0.1 and 5 microM) resulted in a dose-dependent reduction of the uptake of [3H]DA, which had a maximum effect at 5 microM. Further increase in the concentration of MPTP (from 10 to 200 microM) resulted in progressive attenuation of the toxic effect. Exposure to 200 microM MPTP did not produce significant reduction in the uptake of [3H]DA. Increased survival of DA neurons at the higher concentrations of MPTP, was documented by catecholamine histofluorescence and by T-OH immunocytochemistry in cultures treated with 10 and 100 microM MPTP. MPTP was shown to be a potent inhibitor of MPP+ uptake by DA neurons in culture. In the presence of 100 or 200 microM MPTP, the uptake of MPP+ was reduced to less than 20% of control levels. Therefore, the reduction of MPTP toxicity at the high concentrations can be explained, at least in part, by the inhibition of the uptake of MPP+ (the toxic metabolite of MPTP oxidation) in the presence of high concentrations of MPTP.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1987

Effects of puromycin on rat embryos in vitro.

Somite-staged rat embryos were exposed to varying concentrations of puromycin for 48 h in vitro. Medium concentrations below 0.92 microM had no significant effects, while concentrations above 1.84 microM were lethal. Between these extremes, there were concentration dependent increases in the incidence of malformations in a close relationship to growth retardation.

Abnormalities, Drug-Induced↗
PubMed1987

Methionine and iron as growth factors for rat embryos cultured in canine serum.

Development of headfold-staged rat embryos cultured in canine serum containing various supplements was compared with development in rat serum to seek suitable alternatives to rat serum in rodent embryo culture and to identify nutritional factors for cultured rodent embryos that may have relevance for normal mammalian embryonic growth and development. Supplementation of canine serum with glucose, methionine, and a lipophilic iron chelate allowed growth and development of cultured rat embryos, approximating those obtained with rat serum. These findings suggest that properly supplemented canine serum can serve as a suitable rodent embryo culture medium and that glucose, iron, and methionine may be important nutrients in mammalian embryonic development.

Animals↗
PubMed1987

Brain computed tomography in morbid obesity before and after gastric restriction surgery: a prospective quantitative study.

Linear brain parameters were measured by CT in 19 patients with morbid obesity (mean weight 126.4 +/- 20.5 kg) and 20 age and sex matched normal weight subjects (mean weight 62.6 +/- 14.9 kg). Ventricular parameters were slightly smaller and cortical parameters were slightly larger in the preoperative obese than in control subjects. However, only the four cortical sulci ratio was significantly different in the two groups (P = 0.02). After gastric restriction surgery and drastic weight loss (mean postoperative weight 82.9 +/- 27.4 kg), all the ventricular and cortical parameters increased, with significant change in the frontal interhemispheric fissure ratio (P less than 0.05). Obese patients followed for 23 months after surgery had less striking changes than those followed for 6 months. Morbidly obese subjects have altered brain CT dimensions which are partly reversible after weight correction.

Adult↗
PubMed1987

"Cluster-ion" bombardment of biological macromolecules: Morphological evidence for disassembly of single tobacco mosaic virus particles.

Cluster ions containing 50, 100, or 200 water molecules and one proton are accelerated to over 275 kV and impacted on thin carbon films on which tobacco mosaic virus has been dispersed. After bombardment the films are examined with a transmission electron microscope to study induced morphological alterations with respect to the energy transfer processes that take place during and after single cluster-ion impact. Observations on tobacco mosaic virus indicate that a single cluster impact results in the removal of a cylindrical segment of the virus. No fragments from the excised TMV segment were observed on the carbon foil. We speculate that cluster-ion bombardment may become a useful analytical technique for structural studies of large biological macromolecular complexes.

Journal Article↗