Biomedical subjects
Publications and source records attributed to J Feldman.
Neural retina aggregation and adhesion assays, shown to be sensitive to the presence of small number of malignant cells, were differentially inhibited by cells or medium from B16 mouse melanoma sublines with higher metastatic characterizations, which suggests a correlation between inhibition of adhesion and aggregation and metastatic potential.
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A new operant conditioning program, based upon principles of errorless discrimination learning, was used to assess stereopsis in 24-35 months old children. Results indicated that this program was more successful in generating responding to stereograms than standard contour or random dot tests of stereopsis. It was concluded that the most effective procedure for evaluating subjective visual findings in pre-verbal patients is one that recognizes the importance of programmed discrimination learning and operant motivational techniques.
Monocular visual acuities in a binocular field of view, field of view under binocular conditions, and retinal correspondence were investigated in five intermittent exotropes of the divergence excess type. Results indicated that all five intermittent exotropes demonstrated (1) normal visual acuity in the deviating eye without suppressing the fixating eye, (2) a lateral extension of the temporal field of view (panoramic viewing), (3) anomalous retinal correspondence.
Flows measured from maximal expiratory flow-volume (MEFV) curves were used to evaluate the efficacy of postural drainage in improving ventilatory function acutely. Maximal expiratory flow-volume curves were obtained for 9 cystic fibrosis subjects and 10 subjects with chronic bronchitis before and 5, 15, and 45 min after a 30-min session of postural drainage with percussion, vibration, and coughing. Forced vital capacity (FVC) was significantly increased 45 min after drainage for the combining group. Flows at high lung volumes were different for the 2 subgroups. Subjects with cystic fibrosis demonstrated a significant increase in peak expiratory flow rates 45 min after drainage and an increase in forced expiratory volume in one sec at all time intervals. The subjects with chronic bronchitis had a decreased peak expiratory flow rate 5 min after drainage, but by 45 min, it had returned to baseline. There was no significant change in one-sec forced expiratory volume at any time interval for the chronic bronchitis subgroup. Changes in flows at low lung volumes were similar for the 2 subgroups. Forty-five min after drainage there was an increase in flow rates near 50 per cent of FVC. Flows near 25 per cent of FVC were increased 15 and 45 min after drainage. This study demonstrated that postural drainage with coughing resulted in significant improvement in flows at low lung volumes. Changes in flows at high lung volumes were less consistent.
The authors describe an adult mental health service within a health maintenance organization and present information on the department's setting, staffing patterns, programs, and philosophy. They believe that the emphasis on brief focal psychotherapy, the staff of mental health care providers who are committed to this type of setting, and the thorough integration of the program into the larger HMO system all contribute to the provision of high-quality services at a reasonable cost.
A new random dot stereoscopic test, the Frisby Stereo Test, was evaluated to determine whether monocular information may be used in making correct responses. The performance of 34 optometry students was assessed under both monocular and binocular viewing conditions. Results indicated that one student was able to pass the test upon the initial monocular presentation. Two additional students were able to pass the test monocularly following binocular exposure. It was concluded that the Frisby Stereo test is about as effective as any other commercially available RDS test when used with adults. However, it may have potential deficiencies when used with children.
The stereo acuities of 112 children between 3 and 11 years of age were assessed using the Titmus, TNO, and Randot stereo acuity tests. Results indicated that stereo acuity test scores improved with age and that performance variability decreased with age. Normal adult findings were achieved by age 7. Generally the Randot Stereo test yielded the best stereo acuity performances. It was concluded that the Randot stereo test is a better clinical test for use with children than either the Titmus or TNO stereo tests.
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Stereposis was assessed in 94 children ages 2--5 yr using random-dot stereograms (RDSs) and operant conditioning. After five traditional screening tests of stereopsis, all children were trained to perform a match-to-sample discrimination task involving RDSs with and without lateral disparity. An added feature of the operant RDS task was the availability of monocular cue-fading for children who failed initial RDS testing. The operant RDS test facilitated stereopsis-based responding more than the traditional clinical tests did. This finding is interpreted as indicating the importance of such factors as attention, motivation, and language ability in the assessment of stereopsis in young children.
Stereopsis performance was assessed in 88 optometric patients using an operant match-to-sample discrimination task involving random dot stereograms (RDSs). All normals passed the RDS test, and all constant strabismics without amblyopia, microtropes, and amblyopic strabismics failed. Only a portion of anisometropic amblyopes, intermittent strabismics, and ocular-pathology patients passed. The findings were interpreted as indicating that stereopsis with a RDS may be better predicted and explained in terms of binocular fusion and bifoveal alignment than by visual acuity.
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Muscimol, a rigid analogue of GABA has been injected in the CNS of urethane anesthetized, normotensive cats. Injected either intracisternally (1 or 2 microgram/kg, 0.05 ml) or directly by microinjection in a restricted ventrolateral region of the brain stem (0.5 or 1 microgram/kg, 0.5 microliter), muscimol induced hypotension and bradycardia. These central cardiovascular effects of muscimol were antagonized by bicuculline, a "specific" GABA antagonist agent. These data emphasize the involvement of gabergic mechanisms in the central cardiovascular control, at least in the ventrolateral part of the medulla oblongata.
The connections between the areas 'S' which have been previously described as the ventromedullary sites of the action of clonidine and the posterior hypothalamus have been investigated. Superficial electrocoagulation of the left area 'S' suppresses the pressor response to electrical stimulation of the homolateral part of the posterior hypothalamus. Although such medullary lesions cause a significant reduction of the mean arterial pressure, the contralateral hypothalamic stimulation can still increase blood pressure. Clonidine it self applied topically (8 micrograms/kg) to the ventral face of the brain stem decreases the blood pressure response to liminal hypothalamic stimulation. It is concluded that efferent pathways, which are involved in vasomotor regulation, originate in the posterior hypothalamus and run through the ventrolateral part of the brain stem. The mechanism of the blocking effect of clonidine on these pathways is discussed.
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Serum antibodies to cow milk proteins and ovalbumin were measured quantitatively. Food hypersensitivity of the immediate type was determined to be present or absent by skin tests and double-blind food challenges. Elevated levels of antibodies to milk proteins in sera characteristic of infants fed cow milk were found to decline with age, so that sera from children who were 6 to 15 years of age (inclusive), not hypersensitive to food, had significantly lower levels than the infants. In contrast, sera from age-matched children, who were shown to have hypersensitivity to some food, were found to have levels of antibodies to milk proteins as elevated as in infancy. Hypersensitivity was not necessarily to milk but often to some other food. This persistence of greater antibody production to milk throughout childhood in those hypersensitive to some food indicates a fundamental difference from those without hypersensitivity to food, either in permeability, in immunological reactivity of the gut or in development of immunological unresponsiveness. Implications for pathogenesis of clinical disorders are discussed.