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Biomedical subjects

A Shulman

Publications and source records attributed to A Shulman.

At least 109 records · Page 6Linked to original sources
PubMed1988

The guinea-pig isolated atrium as a model system for the central actions of selected CNS stimulant and depressant drugs. Part 2. Mechanisms involved in the actions and interactions of the convulsant bemegride and its hypnotic homologue 3-methyl-3-n-butylglutarimide.

The present study explores pharmacologically on the model spontaneously beating 3H-noradrenaline pretreated guinea-pig atrial preparation the mechanism(s) by which the representative central nervous system (CNS) stimulant drug 3-methyl-3-ethylglutarimide (bemegride, MEG) and its representative CNS depressant homologue 3-methyl-3-n-butylglutarimide (MBG) affect transmitter release and the force and rate of atrial contraction and contracture, as well as the relevance of these atrial mechanism(s) to those involved in the production of drug-evoked convulsions and hypnosis in the mammalian CNS. The process(es) involved in the interaction of MEG and MBG on the atrial preparation have also been studied to provide insight into possible CNS mechanism(s) that may be involved in the related central phenomena of drug-induced analepsis and anticonvulsant action. It would appear that the actions and interactions of MEG and MBG on the atrium and in the mouse both depend critically on glutarimide-evoked enhancement (MEG) or inhibition (MBG) of Ca2+ flux through potential-operated Ca2+ channels located primarily on the responsive atrial sarcolemmal and neuronal synaptic membranes, respectively. In addition, it seems likely that the reciprocal antagonism shown by these substances on the atrium and in the CNS is predominantly functional in nature. The pharmacological and clinical implications of these findings are discussed, with particular reference to the possible benefit of selective calcium antagonists and related drugs in the management of drug dependence and withdrawal.

Animals↗
PubMed1987

Electrical high-frequency audiometry. Preliminary medical audiologic experience.

This paper reports our clinical experiences with the electrical high frequency audiometer (EHFA)-Tonndorf, used in conjunction with conventional audiologic site of lesion testing. The EHFA is routinely used in the site of lesion hearing evaluation battery. We are reporting on the first 100 subjects, aged 6-85 years, seen in otologic/neurotologic consultation for complaint(s) of hearing loss, tinnitus, vertigo, ear blockage alone and/or in combination from 1983 to 1985. The significance of the data obtained suggests that: (1) Patient responses with EHFA are influenced by age, degree of hearing loss, degree of ear disease, site of lesion and disease, noise exposure and ototoxicity. (2) The degree of hearing loss as well as symmetry (asymmetry) of the loss affect the EHFA responses. (3) Responses to EHFA can be correlated with subject group classification. Five groups were well defined based upon degree and symmetry (asymmetry) of the hearing loss. (4) Electrical high-frequency audiograms (EHFAs) can be classified into five different patterns of response. (5) EHFA should be part of a site-of-lesion audiometry test battery.

Adolescent↗
PubMed1987

The guinea-pig isolated atrium as a model system for the central actions of selected CNS stimulant and depressant drugs. Part 1: 3,3-Diakylglutarimide homologues and related drugs.

The 3H-noradrenaline pretreated, spontaneously beating, guinea-pig atrial preparation has been used as a model system to study the presynaptic and postsynaptic actions of selected drugs with stimulant (bemegride, pentylenetetrazol, picrotoxin, strychnine and 4-methyl-4-n-propylpiperidine hydrochloride), depressant (pentobarbitone, hydroxydione, trimethadione, 3-methyl-3-n-alkylglutarimide where alkyl = butyl, amyl or hexyl, 4-methyl-4-n-propylpiperidone-2 hydrochloride, chlordiazepoxide and chlorpromazine) or dual stimulant-depressant (3-methyl-3-n-propylglutarimide and 5-ethyl-5-(1,3-dimethylbutyl) barbiturate and its (+) and (-) enantiomers) actions in the central nervous system of the mouse. 3H-Noradrenaline efflux and force and rate of atrial contraction were used as parameters of atrial function. With the exception of strychnine, picrotoxin and 4-methyl-4-n-propylpiperidine hydrochloride, which appear to act by different central mechanisms, there is good correspondence between the actions of the test drugs on the force of atrial contraction and in the CNS of the mouse. Thus, stimulant drugs increase and depressant drugs decrease the force of atrial contraction, while dual stimulant-depressant drugs in low concentrations increase, and in higher concentrations, decrease the inotropic response. A similarly good correspondence generally exists between mouse and atrium with respect to the relative stimulant and depressant potencies of the test drugs, additive stimulation or depression for pairs of like-acting drugs and 'analepsis' and 'anticonvulsant activity' for drugs with opposed central actions. No such relationships were found using tritium efflux or the chronotropic response as parameters of atrial function. Thus, the guinea-pig atrial preparation appears to be a good model system in which to demonstrate the acute CNS actions and interactions of the majority of the test drugs. Their positive and negative inotropic effects on the atrium have been explained in terms of a membrane phase distribution hypothesis of drug action, and their ability to facilitate or impede, respectively, the movement of Ca2/ across the atrial sarcolemmal membrane. It is proposed that these drugs may act by similar mechanisms at responsive sites in the brainstem reticular formation and related areas in the mouse. These may be primarily excitatory noradrenergic synapses integrated functionally with presynaptic or independent inhibitory GABAergic terminals.

Animals↗
PubMed1987

External electrical tinnitus suppression: a review.

Our experience with transcutaneous electrical stimulation for tinnitus suppression has been with the Theraband Headset from Audimax Inc. The purpose of this article is to review the highlights of the patients who exhibited tinnitus suppression and/or tinnitus control, and to provide an update of our results and techniques using external electrical stimulation with prolonged stimulation (stage IV). Patient selection is considered critical to the success of external electrical stimulation for tinnitus suppression. The key elements include the clinical finding of a peripheral site of lesion of the tinnitus; positive maskability of the symptom of tinnitus; absence of active ear disease; absence of a vestibular asymmetry; and absence or minimal evidence of dysfunction of the central auditory system. The protocol described for patient selection allows for tinnitus identification, the differentiation of clinical tinnitus types, and the clinical application of the concept of the dynamic range of electrical tinnitus suppression. External electrical tinnitus suppression is believed effective in a limited number of patients clinically identified as having a tinnitus site of lesion primarily peripheral in location and cochlear in type. The present device is not commercially available at this time. Both specific and general suggestions are proposed for the standardization of methods of reporting results of electrical tinnitus suppression and tinnitus control.

Electric Stimulation Therapy↗
PubMed1987

Tinnitus suppression.

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Electric Stimulation Therapy↗
PubMed1986

Studies on the development of physical dependence on barbitone in the rat and rat atrium.

The mechanisms underlying the development of barbitone dependence have been studied in the rat and in atrial preparations removed from dependent animals. Long-term oral administration to the rat of barbitone, alone or together with the analeptics bemegride or pentylenetetrazol, has shown that the intensity of the withdrawal syndrome generally parallels the degree of associated CNS depression. In addition, the overall relationship between the spontaneous or evoked (chemical or audiogenic) responses of representative drug-withdrawn rats and the inotropic responses of corresponding withdrawn atria to supramaximal nerve stimulation, noradrenaline or Ca2+ was reasonably good. It is proposed that the rat atrial preparation may provide a suitable model system for the study of barbitone dependence in the rat, especially in relation to Ca2+-dependent mechanisms, and that selective calcium antagonists may prove helpful in the management of barbiturate and similar types of drug dependence. The barbitone withdrawal syndrome has been described in terms of a membrane phase distribution hypothesis of drug action.

Animals↗
PubMed1984

The neurologic implications of tinnitus.

One hundred twenty-one patients with chronic tinnitus were examined for associated neurologic lesions. A routine otologic evaluation was supplemented by an extensive neurologic evaluation, which usually included computed tomography with special views of the posterior fossa. Twenty-one percent of these patients had neurologic disease that appeared to be responsible for the tinnitus. Twenty-three percent had neurologic problems associated with or evolving in concert with the tinnitus, but the auditory complaint could not be confidently ascribed to the CNS disease. Several patients had neurologic or psychiatric problems uncovered during the evaluation that were clearly unrelated to the auditory complaint. The high incidence of neurologic disease in association with tinnitus indicates that tinnitus is often an early sign of CNS disease. Chronic tinnitus justifies a rigorous neurologic evaluation of the affected person regardless of the character of the tinnitus.

Adult↗
PubMed1981

Central tinnitus--diagnosis and treatment. Observations simultaneous binaural auditory brain responses with monaural stimulation in the tinnitus patient.

Central tinnitus is defined as an abnormal sensation of sound which is perceived by the patient and established by neurotologic diagnosis to be retrocochlear and/or within the central nervous system in location. A method of diagnosis and evaluation using evoked response audiometry (ABR) is reported. A clinical test, Simultaneous Binaural Auditory Brain responses with monaural stimulation (ABR) for central location of tinnitus is presented. The use of a diagnostic approach to the selection of a tinnitus masker will be presented. Electrophysiologic indices for central tinnitus have been observed based on short latency ABR recordings. A classification has been presented. The use of lidocaine I.V. therapy with ABR recordings is presented. The concept, diagnosis, and techniques at this time, relating to central tinnitus, are presented as clinical observations. These observations are a beginning for the establishment of an electrophysiologic series of indices which can be interpreted as an electrophysiologic correlate of tinnitus to be supported by basic clinical research.

Audiometry↗
PubMed1981

Tinnitus classification: medical audiologic assessment.

Medical-audiologic assessment for tinnitus classification is essentially an attempt to objectivize the subjective complaint. An attempt is made to classify the symptom by a pattern of test results including: 1. Audiologic test findings; 2. Vestibular test findings; 3. Tinnitus description, by frequency spectrum and intensity level; 4. Residual inhibition, both its presence or absence, and its duration; 5. Masking-curve data and typing of homolateral and contralateral curves of narrow band and pure tone where applicable. The collection of these data is necessary to establish etiology in terms of the medical site of the lesion, audiological site, and tinnitus site. The audiologist and the otologist must work together to establish the proper diagnosis and develop the most effective treatment for the patient who presents tinnitus as the chief complaint.

Female↗
PubMed1978

Comparative actions of 1,10-phenanthroline nickel(II) chelates and their constituent metal ion and ligands on the guinea-pig isolated atrium.

The actions of fully co-ordinated, inert nickel(II) chelates of 1,10-phenanthroline and 3,4,7,8-tetramethyl-1,10-phenanthroline have been compared on the guinea-pig isolated atrium with those of their constituent metal ion and ligands. In general, each test substance showed distinctive actions suggesting that the effects of the metal chelates are mediated by the intact chelate cation and not by liberated metal ion or ligand. Differences in the actions of the unsubstituted and the highly methylated compounds may result from the greater capacity of the methylated chelate and ligand to induce more profound and sustained conformational changes in the responsive atrial pre- and postsynaptic membranes thereby promoting more rapid and prolonged influx of Ca2+.

Animals↗