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Biomedical subjects

J Baron

Publications and source records attributed to J Baron.

At least 217 records · Page 12Linked to original sources
PubMed1981

Individual differences in the classification of stimuli by dimensions.

In two experiments, adults differing in general mental abilities ("intelligence") were given multidimensional classification tasks: aural and visual free-classification tasks that allowed grouping of triads or trends by conflicting criteria of dimensional identity or overall similarity, and a speeded classification task that required the filtering of variation in an irrelevant dimension. Four principal results are reported: (a) Individual differences in the tendency to use similarity criteria in free classification were systematic across modalities and stimulus dimensions; (b) filtering performance, measured as the effect of irrelevant variation on speeded classification, did not correlate with free-classification performance (percent similarity responses); (c) the tendency to use similarity criteria in free classification was not correlated with intelligence; and (d) the amount of interference in speeded classification was correlated negatively with intelligence. The results taken together suggest that there are two dimensions of individual differences in perceptual analysis, one having to do with ability and the other with style or preference. This suggestion was supported by an additional analysis. The results also raise questions about the convergence of measures of multidimensional stimulus processing.

Discrimination Learning↗
PubMed1981

Postsplenectomy splenic activity.

Evidence of recurring activity of splenic tissue was investigated in patients who had undergone splenectomies. Methods included technetium 99m sulfur colloid scan, serum tuftsin assay, serum immunoglobulin concentration, blood cell counts, and search for Howell-Jolly bodies. Positive scans were observed together with normal levels of tuftsin in 54% of the patients. In 46% of the patients, no splenic activity was detected by scanning and low levels of tuftsin were noticed. The difference in tuftsin levels between the two groups was statistically significant. Howell-Jolly bodies and decreased serum levels of IgM featured all patients. The possible application of combined splenic scan and tuftsin assessment for screening recurring splenic activity in the postsplenectomy population at great risk is suggested.

Adolescent↗
PubMed1981

[Hypothalamic amenorrhoea, following deficient nutrition (author's transl)].

Clinical and hormonal examinations were applied to 30 patients with secondary amenorrhoea, following loss of weight, and to another 24 women with nervous anorexia. Low age, secondary amenorrhoea, and unambiguous loss of weight were typical of all patients. In patients with hypothalamic syndrome, following loss of weight, both psychic condition and appetite were found to be normal, whereas psychogenic aversion against appetite was recordable from patients with nervous anorexia. Oestrogens were slightly reduced in patients with hypothalamic syndrome, following loss of weight, but they were strongly down in the presence of nervous anorexia. Gonadotrophin values were normal or low in patients with hypothalamic syndrome, following loss of weight, but they were clearly reduced in the second group. The LH-RH test usually was normal in patients with hypothalamic syndrome, following loss of weight, but it was pathological in almost all cases of nervous anorexia, depending on the amount of weight loss.

Adolescent↗
PubMed1980

Overcoming Stroop interference: the effects of practice on distractor potency.

With practice, do distracting stimuli lose their ability to distract? In a series of experiments, subjects practiced counting digits, a task subject to Stroop-type interference, and then were tested in a variety of transfer conditions. The results indicate that digits do lose their ability to distract as a result of practice but that this loss is highly specific; practice in ignoring one pair of distractors (2 and 4) does not improve later performance when ignoring a different pair (1 and 3). However, this practice effect does transfer to distractor stimuli having the same meaning as the stimuli ignored in practice (TWO and FOUR, but not TO and FOR). The results can be explained either in terms of active learning to suppress distraction or in terms of habituation of competing responses.

Attention↗
PubMed1980

[Radio-immunological determination of testosterone and of sexual hormone binding globulin in plasma of women with hirsutism (author's transl)].

Plasma-borne testosterone was determined in 176 women with hirsutism, and in 47 patients sexual hormone binding globulin was determined as well. The highest average testostercne values were recorded from cases with congenital AGS. In cases of postnatal AGS values were much lower, but they were clearly in excess of those recordable from Stein-Leventhal syndrome. Plasmaborne testosterone in cases of hirustism came very close to testosterone levels established in the context of Stein-Leventhal syndrome. Testosterone levels dropped with significance, following AGS treatment, using cortisol derivatives, and following wedge-shaped ovariectomy. Sexual hormone binding globulin was found to be strongly reduced in almost all women with hirsutism. Such reduction seemed to suggest the presence of increased amounts of free active testosterone in the blood of those patients. Determination of plasma-borne testosterone in cases of hirsutism is considered to be essential to both diagnosis of the endocrinological syndromes and monitoring of therapy.

Adrenal Hyperplasia, Congenital↗
PubMed1980

Exposure to radioiodine in the preconception and conception periods. A case report.

A case of radiation exposure shortly before conception is presented. The patient refused abortion and was delivered of a healthy infant. On reconsideration of the case, it was decided that the recommendation to terminate the pregnancy on the grounds of excessive exposure to radiation was unjustified. We feel that physicians should be aware that abortion in such cases is not always necessary.

Abortion, Therapeutic↗
PubMed1979

Immunohistochemical studies on electron transport proteins associated with cytochromes P-450 in steroidogenic tissues. II. Microsomal NADPH-cytochrome c reductase in the rat adrenal.

NADPH-cytochrome c reductase (NADPH : ferricytochrome oxido-reductase, EC 1.6.2.4), the flavoprotein which mediates the NADPH-dependent reduction of cytochromes P-450 in adrenocortical microsomes, has been localized immunohistochemically at the light microscopic level in rat adrenal glands. Localization was achieved through the use of sheep antiserum produced against purified, trypsin-solubilized rat hepatic microsomal NADPH-cytochrome c reductase in both an unlabeled antibody peroxidase-antiperoxidase technique and an indirect fluorescent antibody method. The sheep antibody to rat hepatic microsomal NADPH-cytochrome c reductase concomitantly inhibited the NADPH-cytochrome c reductase and progesterone 21-hydroxylase activities catalyzed by isolated rat adrenal microsomes. When sections of rat adrenal glands were exposed to the reductase antiserum in both immunohistochemical procedures, positive staining for NADPH-cytochrome c reductase was observed in parenchymal cells of the three cortical zones but not in medullary chromaffin cells. The intensity of staining, however, was found to differ among the three cortical zones, with the most intense staining being found in the zona fasciculata and the least in the zona glomerulosa. The intensity of staining was also found to differ among cells within the zona fasciculata. These immunohistochemical observations demonstrate that microsomal NADPH-cytochrome c reductase is not distributed uniformly throughout the rat adrenal cortex.

Adrenal Cortex↗
PubMed1979

Radionuclide assessment of aortocoronary bypass surgery.

Rest and exercise thallium 201 myocardial scintigraphy and multiple gated radionuclide angiography were correlated with the results of clinical status, exercise electrocardiography, coronary arteriography, and contrast left ventriculography in a series of 12 prospectively studied consecutive patients before and after aortocoronary bypass operation. Patients were divided into two groups based on a comparison between preoperative and postoperative 201T1 scintigrams. Group 1 (6 patients) demonstrated improved or normal postoperative perfusion scintigrams and excellent correlation between the site of a patent graft and the improvement in myocardial perfusion on the postoperative exercise scintigrams. Regional wall motion remained normal in 3 patients and improved in 3. In Group 2 (6 patients) the postoperative 201T1 scintigrams were unchanged or worse. Each patient demonstrated graft occlusion, graft stenosis, distal disease, or a perioperative myocardial infarction. No improvement in regional wall motion occurred in 4 of these 6 patients. Neither the symptomatic response to aortocoronary bypass operation nor the response to exercise testing successfully predicted graft patency.

Adult↗