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Biomedical subjects

A Feldman

Publications and source records attributed to A Feldman.

At least 91 records · Page 5Linked to original sources
PubMed1979

The effect of active versus passive exploration on memory for spatial location in children.

The effect of active exploration upon memory for spatial location of an event was assessed for children at 2 age levels. Each child took a walk through the same unfamiliar hallway in search of a hidden object which he was later asked to relocate. Half the children were accompanied by an adult holding their hand (passive condition), while the other half proceeded on their own with an adult following behind (active condition). An age x condition interaction revealed that active exploration significantly improved performance of the 3- and 4-year-old group while not affecting the performance of the 9- and 10-year-olds. The 3- and 4-year-olds in the active condition, however, were still significantly less accurate than the older children, despite their experience of self-directed exploration. The results are interpreted as supporting the hypothesis that self-directed activity serves to increase attention of preoperational children to relevant topological cues in the environment, whereas concrete operational children, due to their knowledge of projective and Euclidean space, demonstrate increased capacity to efficiently encode spatial information regardless of the mode of exploration.

Child↗
PubMed1978

The family practitioner as psychiatrist.

The author describes attitudes held by nonpsychiatric physicians that are responsible for poor psychological handling of patients, including low interest in psychosocial aspects of illness, judgment of and disinterest in hypochondriasis or conversion reaction, avoidance of psychotic or terminally ill patients, and anger toward patients with unpleasant characteristics. He discusses reasons for these attitudes and suggests that medical schools increase psychological education and psychiatry departments increase the relevance of their teaching.

Attitude of Health Personnel↗
PubMed1977

[Moschowitz's disease: efficacy of anti-platelet aggregation agents].

In November 1976, a 52 year old woman presented with a Moschowitz syndrome with clinical manifestations of continuous fever at 39 degrees and a transient Wernicke type aphasia. Laboratory findings included schizocytosis, a peripheral thrombocytopaenia and functional renal insufficiency. The ethanol tests was positive but there was no frank defibrination syndrome. After corticosteroid therapy failed, the patient was treated with Dipyridamole 400 mg/24 hours IV and acetylsalicylic acid 4 g/24 hours IV. Fever disappeared on the same day and the thrombocytopaenia was corrected in 48 hours. The patient was considered to be cured 15 days later. No precise aetiology to explain the Moschowitz syndrome was discovered apart from the recent ingestion of oestrogens. The authors emphasise the considerable progress which this use of a combination of Dipyridamole and aspirin represents, resulting in the cure of Moschowitz syndrome, a condition considered to be fatal up until a few years ago.

Adrenocorticotropic Hormone↗
PubMed1977

SI prefixes.

Explore the source record for details and available documents.

Documentation↗
PubMed1976

Effect of prolactin on maintenance of prelactating human mammary gland in vitro.

Human mammary tissue from a female at the end of the second trimester of pregnancy was studied in organ culture in a chemically defined medium. Sampling was carried out at 1, 2 and 3 weeks. Without hormones, there was nearly total lobuloalveolar degeneration in all specimens at all times. Addition of insulin, hydrocortisone and ovine prolactin, in combination at a concentration of 5 mug per ml each, did not affect the extent of degeneration. Raising the concentration of prolactin to 50 mug per ml resulted in greatly improved lobulo-alveolar maintenance in all specimens and continued epithelial cell DNA synthesis for up to 3 weeks in vitro.

Breast↗
PubMed1975

In vivo electron spin resonance in rats.

In vivo ESR studies have been made on Wistar and Sprague-Dawley rats using travelling wave helices implanted in the left lobe of the liver. Tissue regenerates completely around the Teflon-enclosed turns of the coil and histological studies have shown that it is composed of liver cells and connective tissue. Electron spin resonance studies of this tissue in vitro reported by Commoner and Ternberg in 1961 have demonstrated that it exhibits the 'tissue radical' signal. The implanted coils have detected, in vivo, a three-line spectrum due to a strong concentration of 4-hydroxy- 2,2,6,6-tetramethylpiperidine-1-oxyl free radical ('tempol'), a nitroxide spin label, injected either intramuscularly, intraperitoneally or intravenously into the experimental animal immediately prior to the measurement. They have also detected, in vivo, a similar three-line spectrum due to 'spin-labelled chlorpromazine', a tranquillizing drug to which this nitroxide spin label has been attached, injected intramuscularly or intraperitoneally into the animal immediately prior o the measurement. Work is currently in progress to increase the in vivo sensitivity of the implanted helices by menas of improved coupling techniques and the use of a time-averaging computer.

Animals↗
PubMed1975

The role of the middle ear in acoustic trauma from impulses.

Exposure to high intensity impulse noise may produce a wide range of audiometric and histological effects in experimental animals. The objective of this study was to assess the changes in the middle ear mechanism after impulse noise exposure and to relate these changes to the audiometric and histological effects. Nine monaural chinchilla were exposed to either 161 or 166 db peak SPL impulses of 1 msec "A" duration, presented at a rate of 1 per minute for 50 minutes. The conductive mechanism of the chinchilla was assessed using standard clinical measures of static and dynamic impedance before and after the noise exposure. Auditory thresholds were measured before and after noise exposure using the average evoked response (AER) technique. At 30 days post-exposure, the animals were sacrificed for histology. Pre-exposure tympanometry showed that: 1. the total mean impedance of the chinchilla ear is considerably lower than that of man; 2. a method related hysterisis effect is present in both the susceptance and conductance tympanograms; and 3. sedation has a significant effect on the total impedance of the ear and on the shape of the tympanograms. After exposure to high level impulse noise: 1. tympanograms become irregular and double peaked, indicating tympanic membrane stress; 2. for the given exposure, 166 db is the impulse intensity needed to rupture consistently the tympanic membrane; and 3. audiometric and histological data correlate with the tympanometric findings and demonstrate a protective effect of a tympanic membrane rupture on the cochlea.

Animals↗
PubMed1975

[Chronic pulmonary artery thrombosis. Therapeutic modality. Apropos of 6 cases].

Six cases of post-embolic chronic cor pulmonale are presented. All six were treated with thrombolytic agents (4 with streptokinase, 2 with urokinase), and in only one case was improvement maintained at the end of one year. Two patients underwent a disobliterative procedure of the pulmonary artery, together with ligation of the inferior vena cava. One of these operations was unsuccessful, and the other had a successful outcome, as confirmed by objective assessment with angiography, scintigraphy and haemodynamic studies. The literature is reviewed at this stage. It was found that the fibrinolytic agents had some chance of working only if the condition was less than a few months old. One major drawback to surgical disobliteration that cannot be foreseen before operation is the presence of thromboses at the arteriolar level in subjects whose main arteries are already blocked proximally. Nervertheless it is possible to obtain good results by surgery, and the operation is worth attempting in young subjects, given the poor prognosis of the untreated condition.

Adult↗
PubMed1974

Reversion of a Chinese hamster cell auxotrophic mutant.

A mutant cell strain derived from a Chinese hamster line by mutagenesis with ethylmethane sulfonate requires glycine for growth. In the wild type, glycine synthesis is catalyzed by serine hydroxymethyltransferase (EC 2.1.2.1). Cell fractionation by differential centrifugation and isopycnic sucrose gradient analysis reveals that the enzyme activity is found in both the mitochondrial and cytosol fractions. The specific activity in the mitochondrial fraction is about 20 times higher than in the cytosol, and is much more stable to thermal inactivation. The glycine-requiring mutant has lost all of the mitochondrial enzyme activity, while retaining the cytosol activity. The mutant is very stable but can be induced to revert by several chemical mutagens. One glycine-independent revertant induced by ethyl methane sulfonate was studied in detail. Serine hydroxymethyltransferase activity is again present in the mitochondrial fraction, at about [unk] of the wild-type level. However, the revertant mitochondrial enzyme exhibits an altered thermal sensitivity, with a half-life at 45 degrees of 55 min as compared to 180 min in the wild type. The half-life for the cytosol enzyme in all three strains is 7 min. Mixing experiments demonstrate that the heat lability of the revertant enzyme is not due to a dissociable factor in the extract. The data are consistent with the idea that the original mutation occurred in the structural gene for one isozyme of the enzyme and that the revertant has undergone a second mutation in this gene, partially restoring enzyme activity.

Acid Phosphatase↗