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Biomedical subjects

M Mintz

Publications and source records attributed to M Mintz.

At least 91 records · Page 5Linked to original sources
PubMed1981

Ketamine: convulsant or anti-convulsant?

Ketamine hydrochloride in doses producing narcotic-cataleptic effects (50--100 mg/kg, IP) reduced the intensity of picrotoxin convulsions and eliminated seizures caused by metrazol administration. Subcataleptic doses (5--20 mg/kg) increased the duration of mitigated convulsive symptoms (abortive grand mal fits, jerks) especially those evoked by picrotoxin. Narcotic-cateleptic doses of ketamine considerably increased the duration of the period of single and multiple jerks produced by picrotoxin administration. Both convulsants transformed 1--2 Hz "ketamine complexes" into 2--4 Hz Wave spike discharges which appeared in a quasi-periodic fashion alternating with periods of relatively suppressed electrocortical activity. Electroencephalographic grand mal patterns were typically dissociated from behavioral manifestations under 50--100 mg/kg of ketamine, followed by a short period of postictal depression and a rapid recovery of preseizure electrographic patterns. Findings suggest that mechanisms involved in seizure alleviation may be responsible for sustaining mitigated convulsive phenomena. Neuro-chemical processes underlying antiepileptic ketamine potency remain unknown.

Animals↗
PubMed1981

Pharmacologic analysis of the postictal immobility syndrome in the rat.

Postictal immobility (IP) following chemically (pictrotoxin, metrazol) and electrically-induced (maximal electroshock, MES) convulsions has behavioral features close to neuroleptic-type catalepsy. EEG, monitored postictally, showed that catalepsy is accompanied by a variety of EEG patterns. Cataleptic behavior extended beyond the period of "postictal EEG depression". During PI rats had vivid righting and corneal reflexes. Like haloperidol-pretreated rats they were able to maintain uncomfortable postures on the vertical grid or horizontal bar; although signs of rigidity were noticed, the rats would fail to remain self-supporting when placed across metal bookends ("bridge" test). All rats reacted to the tail-pinch immediately when the seizure would halt. However, 10-15 min later when PI was minimal or not detectable, animals became totally unresponsive to pressure applied to the tail ("delayed analgesia"). Examination of VEP recovery after MES showed that the secondary slow negativity and sensory after discharge were well developed irrespective of the score of the tail-pinch test. Pharmacological profile of PI suggests that the endogenous opiate system might contribute to this syndrome. Similar to morphine-induced catalepsy/catatonia: (1) PI is insensitive to atropine and scopolamine; (2) neither haloperidol nor alpha-methyl-p-tyrosine was able to potentiate it; (3) PI is reduced by apomorphine, naloxone, and physostigmine. Also, drugs acting via GABA system (gamma-vinyl GABA, diazepam, sodium valproate) reduce PI intensity. It is hypothesized that PI system (1) is controlled by GABA carrying fibers and (2) uses neuropeptide with neuroleptic properties.

Animals↗
PubMed1981

Convulsant-specific architecture of the postictal behavior syndrome in the rat.

The postictal immobility syndrome was examined in five experimental grand mal epilepsy models in an attempt to analyze separately the behavioral and underlying neurochemical aspects of the rigid-catatonic and flaccid-cataleptic states. Catalepsy and analgesia were found in varying degrees after maximal electroshock (MES), metrazol, picrotoxin, and Ro 5-3663 activated seizures. Signs of rigidity were noticed after the MES and picrotoxin seizures. Kindled seizures were followed by explosive behavior without signs of rigidity, catalepsy, and analgesia. Naloxone reduced the duration but not the score (intensity) of catalepsy and failed to selectively antagonize analgesia. The relative representation of the tonic stage of convulsions seemed to be the major determinant of the development of catatonic-cataleptic symptomatology. It is suggested that more than a single neurotransmitter system is involved in the postictal immobility syndrome and each epilepsy model has its unique neurochemical profile.

Animals↗
PubMed1981

Smooth pursuit pattern in schizophrenic patients during cognitive task.

Asymmetries in saccadic pursuit were studied, using EOG, ion 20 schizophrenic patients, as well as in two groups of normal subjects, screened for their patterns of lateral eye movements (LEM). Tracking performance was also examined while subjects were concurrently engaged in performing a cognitive task. Saccadic pursuit among schizophrenic patients was replicated in the present study. No asymmetry was observed in the quality of leftward as compared to rightward tracking. However, solving syllogisms while tracking resulted in further deterioration in tracking performance of the patients, with significantly more saccades and arrests in tracking occurring when following the target to the left as compared to rightward following. Similar asymmetry was observed in one group of controls who are believed to rely more on their left hemisphere on the LEM test, whereas no asymmetry was observed in the performance of the second control group. These results are interpreted as supporting the hypothesis of left hemispheric hyperactivity in schizophrenia. Saccadic pursuit in one subgroup of the normal sample is considered as suggesting that these individuals belong to the high-risk group.

Adolescent↗
PubMed1980

Electroencephalographic and behavioural effects of sodium valproate in patients with photosensitive epilepsy. A single dose trial.

A single oral dose of Sodium valproate (VPA) given as Epilim (10 mg/kg) inhibited photoconvulsive responses, especially to 15--30 Hz frequency flicker, in seven out of ten patients with photosensitive epilepsy. In addition, in all patients (with an exception of one) the amplitude of the secondary slow negative wave of the visual evoked potentials was reduced 4--5 h after drug administration. However, in five of these patients the normalization of electrocortical reactions to a single flash and flickering light was accompanied by somnolence and fatigue, moderate slowing of EEG background, development of 3 Hz spike-wave activity and (in three patients) augmented response to hyperventilation. In two patients the EEG photoconvulsive discharge was exaggerated by VPA. There VPA effects suggest that photosensitivity and the underlying epileptic condition have overlapping albeit different pathophysiology. The data offer no support for the conclusion that reduced photosensitivity produced by VPA is associated with the therapeutic potency of the drug.

Adolescent↗
PubMed1980

Diagnostic and prognostic value of retinal hemorrhages in the neonate.

Ocular fundi of 410 newborns were examined for retinal hemorrhages within 24 hours after delivery. The purpose of this study was to investigate whether the course of pregnancy and management of delivery influence the incidence of neonatal retinal hemorrhage (RH) and whether this incidence could be reduced by electronic monitoring of delivery. To assess the prognostic value of neonatal RH for future development of the child, the physical, motor, and psychologic states of 252 infants were examined 6 to 18 months following delivery. The incidence of RH was 37.3% and was not influenced by maternal age, parity, gestational age, course of pregnancy, birth weight, or electronic monitoring of delivery. The mode of delivery did influence the incidence of RH. Gesell developmental schedule showed no correlation between ocular findings and later development of the child.

Delivery, Obstetric↗
PubMed1980

Hemisphere laterality and smooth pursuit in normal individuals.

34 right-handed women of college age who consistently responded with leftward ("left-movers") or rightward ("right-movers") reflective lateral eye movements were tested on spatial and non-spatial syllogisms while engaged in an eye-tracking task. Contrary to expectation, no interaction between tracking direction and syllogism type was observed. Left-movers performed better on all tasks. The results are discussed in relation to hemispheric asymmetry.

Adult↗
PubMed1979

Reactive gaze laterality in schizophrenic patients.

Reflective lateral eye movements (LEMs) in response to questions of different categories are indicative of differential hemispheric reactivity. These LEMs were studied in schizophrenic patients and normal subjects, in response to 24 questions (12 visual-emotional and 12 verbal-neutral). Two categories of saccades were observed: short-latency LEMs (S-LEMs) and long-latency LEMs (L-LEMs). S-LEMs are believed to be associated with orienting response mechanism. L-LEMs are considered to be related to decision-making or formulating hemispheric-activity-dependent response strategy. In the present study, a general trend of leftward LEMs was found among normals regardless of the question's category, whereas schizophrenics tended to show predominantly rightward LEMs. This suggests that individual cognitive style, rather than task variables, affects LEM direction. The two types of LEM's and their different involvement in hemispheric activity are discussed.

Adult↗