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Biomedical subjects

S Greenberg

Publications and source records attributed to S Greenberg.

At least 181 records · Page 10Linked to original sources
PubMed1980

Kinesthetic biofeedback: a treatment modality for elbow range of motion in hemiplegia.

Two treatment modalities for increasing active elbow extension with hemiplegic subjects were tested. Twenty subjects were randomly assigned to one of two treatment groups--an experimental treatment technique using kinesthetic biofeedback, or a control group consisting of an occupational therapy approach aimed at increasing functional use of the envolved upper extremity. The results indicate that kinesthetic biofeedback was as beneficial as conventional occupational therapy. It was also demonstrated that an individual's age, sex, or length of time beyond one-year post-CVA did not significantly affect treatment outcome. A majority of subjects in both treatment groups improved in ways not directly related to treatment, which suggests the need for long-term follow up of hemiplegic patients.

Adult↗
PubMed1980

Effect of metabolic inhibitors on 45Ca fluxes and ATP content of myelinated nerve.

The effects of metabolic inhibitors on ATP levels and on 45Ca fluxes were studied in desheathed tibial nerves of Rana pipiens. ATP levels were significantly reduced and Ca influx and efflux increased following exposure to cyanide, mersalyl, azide, dinitrophenol, iodoacetate or ethacrynic acid. The efflux changes were relatively small compared to squid axons but are not attributable to depolarization of the cell or to changes in the transmembrane Na gradient. The magnitude of the effluxes are consistent with ideas about the amount of labile Ca sequestered in energy-dependent Ca pools. The efflux stimulated by metabolic inhibitors is reduced by removing extracellular Na or Ca, indicating that a large portion of Ca efflux in the poisoned state is mediated by Na-Ca countertransport. In the nominal absence of both these cations Ca efflux can be stimulated by metabolic inhibitors, suggesting that mechanisms in addition to countertransport participate in Ca efflux.

Adenosine Triphosphate↗
PubMed1980

Sympathetic neuroeffector transmission to pulmonary vascular smooth muscle in porcine superior mesenteric arterial occlusion (SMAO) shock.

Splanchnic arterial occlusion shock results in pulmonary endothelial damage and depression of porcine intralobar pulmonary artery and vein contractility. This study evaluates the functional integrity of the adrenergic nerves innervating intralobar pulmonary arteries and veins and the changes in neurotransmission following 1) superior mesenteric artery occlusion (SMAO) shock in swine; 2) sequential inhibition of prostacyclin, thromboxane, and prostaglandin synthesis; and 3) mechanical stripping of the endothelium. Rings of porcine intralobar pulmonary arteries and veins were obtained from sham and SMAO shocked swine. They were suspended in muscle baths and stimulated transmurally at 1-32 Hz, 2 msec duration, 2 msec delay at 7.5-10V. Some experiments were performed on rings of intralobular pulmonary arteries and veins in which the endothelium was stripped with a razor blade. Appropriate inverted-reverted controls were used to account for any deleterious effects of the preparatory techniques involved in stripping. Intralobar pulmonary arteries and veins from sham swine contracted in response to 1 Hz, with maximum responses at 32 Hz. The responses to nerve stimulation were enhanced by cocaine and inhibited by phentolamine, an alpha-receptor antagonist. Inhibition of endothelial prostacyclin synthesis, as well as endothelial stripping, diminished by 30-40% the responses to nerve stimulation. The responses to nerve stimulation were depressed in both intralobar pulmonary arteries and veins in SMAO shocked swine. The data demonstrate physiologic regulation of neural control in porcine pulmonary blood vessels. Furthermore, the data suggest that prostaglandin, the vascular endothelium, and shock, may modify this process.

Animals↗
PubMed1980

Dimensions underlying a hierarchically based assessment of social problem-solving.

The dimensions underlying a procedure designed to assess nine levels of social problem-solving among EMR learners were explored in relation to IQ and MA. Principal-factor solutions followed by oblimin rotations were performed on data collected from 120 EMR children (ages 9 to 14). Results yielded three hierarchical factors, two that were moderately related to IQ and MA and one that was independent of IQ and MA. Explanation of the findings was based on a consideration of the differences between divergent and convergent production abilities.

Factor Analysis, Statistical↗
PubMed1979

Alterations in myocardial adenylate cyclase in spontaneously hypertensive rats.

Particulate fractions of myocardium taken from spontaneously hypertensive rats (SHR) contained an adenylate cyclase system that was less responsive than normotensive Wistar Kyoto rats to norepinephrine, isoproterenol (mixed beta-agonist), salbutamol (beta 2-agonist), dobutamine (beta 1-agonist), dopamine, histamine, and glucagon. Addition of 5'-guanylylimidodiphosphate to the SHR myocardial preparation again yielded a lessened sensitivity to all agents except norepinephrine, dopamine, and histamine. Chronic treatment of SHR with clonidine and a high dose of propranolol produced a cardiac enzyme that was insensitive to activation by norepinephrine. Similar treatment with a low dose of propranolol did not alter myocardial responses to norepinephrine.

Adenylyl Cyclases↗
PubMed1979

Hierarchical assessment of social competence.

Three properties associated with the Test of the Hierarchy of INductive Knowledge (THINK) were examined, namely, that the processes assessed by the measure are (a) cumulative and hierarchical, (b) developmental, and (c) related to behavioral criteria. Analyses of data collected from 120 EMR children between the ages of 9 and 14 years generally support the developmental and criterion-related features of the measure, but only partially confirm the hierarchical component. Discussion of the results was focused on the emphasis necessary in subsequent empirical work and the measure's potential for instructional applications in relation to current assessment issues in special education.

Adolescent↗
PubMed1978

Human auditory frequency-following responses to a missing fundamental.

Both a complex tone perceived as a 365-hertz "missing fundamental" and a 365-hertz pure tone evoked 365-hertz far-field frequency-following responses. Narrow-band masking noise centered at 365 hertz attenuated the responses to the pure tone but not to the complex tone. Results support the concept that perception of the missing fundamental is based on periodic neural activity.

Auditory Pathways↗
PubMed1978

Evaluation of tracheal incisions for tracheostomy.

Three standard tracheostomy incisions in dogs were compared to determine whether any were more likely associated with stomal stenosis. Each incision resulted in an average reduction in tracheal lumen of 25 per cent, with a 50 per cent maximum. The incision selected should depend on the conditions present.

Animals↗
PubMed1978

Interaction between alpha adrenergic and serotonergic activation of canine saphenous veins.

Serotonin and norepinephrine produced concentration-dependent contractions of helical strips of canine saphenous veins. The contractile responses to both agonists were inhibited by the alpha adrenergic receptor blocking agent phentolamine. Tolazoline inhibited the contractile responses of canine saphenous veins to norepinephrine but augmented those to serotonin. Blockade of adrenergic neuronal reuptake with cocaine enhanced the sensitivity of the canine saphenous vein to serotonin, but did not suppress the inhibition by phentolamine of the contractile responses to this indolealkylamine. Serotonin-mediated venoconstriction was not secondary to release of norepinephrine since it was not accompanied by an increased release of [7-3H]-norepinephrine. These findings suggest that serotonin does not contract canine saphenous veins by stimulation of typical serotonergic receptors. The binding sites for serotonin and norepinephrine in cutaneous venous smooth muscle may share part of a common receptor complex, which triggers the contractile process. Alternatively, serotonin and norepinephrine may act at two different receptors to elicit contraction of canine saphenous veins.

Animals↗
PubMed1977

Comparison of cromoglycate (cromolyn) and theophylline in controlling symptoms of chronic asthma. A collaborative study.

28 children with chronic asthma (15 in Denver and 13 in London) completed a 12 wk double-blind trial of treatment with sodium cromoglycate (cromolyn sodium), theophylline, and a combination of both. The three regimens were administered, each for 4 wk, in random sequence as part of a collaborative investigation of the relative efficacy of the two antiasthmatic agents. Cromoglycate was administered by inhalation in standard doses of 20 mg q.i.d. Theophylline dosage was individualized with the assistance of serum-theophylline measurements and averaged 6 mg/kg/dose q.i.d. (range 3-8--8-5 mg/kg/dose). Peak expiratory-flow rates measured twice daily on all patients averaged 75% of that predicted during cromoglycate administration, 79% during theophylline, and 81% during the combined-drug regimen (P less than 0.05). Patients had an average of 59% of days free of symptoms while on cromoglycate and 71% of days symptom-free when on both the theophylline and the combination regimens (P less than 0.025). None of the 13 patients whose asthmatic symptoms were previously controlled with cromoglycate was unable to complete the 4 wk trial with theophylline alone; 1 patient whose symptoms had been previously controlled with theophylline twice developed severe asthmatic symptoms while receiving cromoglycate, and he had to be withdrawn from that study period. No significant differences in adverse effects of the medication were observed during the 12 wk trial.

Adolescent↗
PubMed1976

Evidence for enhanced venous smooth muscle turnover of prostaglandin-like substance in portal veins from spontaneously hypertensive rats.

The sensitivity of portal veins from 14 to 18 week-old Okamoto-Aoki spontaneously hypertensive rats to prostaglandins A2, B2, D2 and F2alpha were enhanced whereas the sensitivity to prostaglandin E2 was diminished when compared with responses of veins from normotensive Wistar-Kyoto rats. Inhibition of prostaglandin synthesis with both eicosotetraynoic acid (ETYA) and indomethacin (INDO) abolished the observed differences in sensitivity to prostaglandins. Synthesis of prostaglandin-like substance (with arachidonic acid as precursor) was significantly enhanced in portal veins from spontaneously hypertensive rats. Metabolism of prostaglandins E2 and F2alpha, employing the oil-immersion technique of Kalsner and Nickerson, appeared to be similar in veins from normotensive and hypertensive rats. These findings suggest that prostaglandin synthesis is enhanced in venous smooth muscle from hypertensive rats. The increased concentration of endogenous prostaglandin at the venous smooth muscle cell may modify the responses to exogenously administered prostaglandins thus accounting, in part, for the altered sensitivity to these fatty acids.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1976

Studies on the nature of a prostaglandin receptor in canine and rabbit vascular smooth muscle.

The contractile response of rabbit renal arteries and canine tibial arteries to prostaglandins A2, B2, F2alpha, E1, E2, D2, and B1 was associated with a reduction in total sulfhydryl group content of smooth muscle. The total sulfhydryl content of rabbit renal and canine tibial arteries and was not affected by norepinephrine or potassium chloride. Reduction of disulfide groups with dithiothreitol (DTT) selectively inhibited contractile responses to angiotensin and prostaglandins; 5,5'-Dithiobisnitrobenzoic acid (DTNB), a sulfhydryl group-oxidizing agent, reversed the inhibitory effect of DTT on the contractile responses to prostaglandins. Alkylation of free sulfhydryl groups with ethacrynic acid did not affect the contractile response of isolated canine tibial or rabbit renal arteries to any agonist studied. Ethacrynic acid added to muscle strips exposed to DTT resulted in alkylation of sulfhydryl groups produced by reduction of disulfide bonds and irreversibly prevented DTNB-induced reversal of DTT inhibition of contractile responses to prostaglandins. However, addition of ethacrynic acid to muscle strips contracted by prostaglandins did not inhibit subsequent responses to these acidic lipids. These findings support the hypothesis that contractile responses of rabbit renal and canine tibial arteries to prostaglandins are dependent on interactions between prostaglandins and disulfide groups located in or on the vascular smooth muscle cell, and the concept that membrane disulfide groups may be integral components of vascular smooth muscle receptors for prostaglandins.

Angiotensin II↗