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Biomedical subjects

M Mintz

Publications and source records attributed to M Mintz.

At least 73 records · Page 4Linked to original sources
PubMed1986

Endogenous dopaminergic asymmetry affects development of seizures kindled in the rat amygdala.

Cerebral dominance in 56 rats was determined by observing the direction of their turning behavior in response to injection of d-amphetamine (1.5 mg/kg, i.p.). Rats subsequently subjected to kindling of the amygdala developed full epileptic seizures after significantly fewer kindling sessions if the kindling electrodes were in the amygdala of the nondominant, rather than the dominant hemisphere. Kindling rate also showed a significant negative correlation with the total amount of turning after amphetamine. Rats kindled through electrodes in the ventral mesencephalon generally failed to develop full convulsive seizures, and did not show interhemispheric differences in the rate at which they developed preictal behaviors. As the dominant hemisphere of the rat, identified by rotational preference, contains a higher concentration of dopamine, we conclude that even small differences in dopaminergic activity, within the normal physiologic range, can affect the relative susceptibility of the two hemispheres to the development of kindled epilepsy.

Amphetamine↗
PubMed1986

Exposure to amphetamine after substantia nigra lesion interferes with the process of behavioral recovery.

Recovery from unilateral substantia nigra lesion may be indicated by re-emergence of circling in the pre-lesion preferred direction. Following 6-OHDA-induced lesion of the dominant SN, we examined: (a) The effect of the delay from lesioning on amphetamine-induced rotation asymmetry, and (b) The effect of early post-lesion exposure to amphetamine on later rotation asymmetry. d-Amphetamine was initially injected either 7, 14, 21, or 30 days after lesioning. Transient circling in pre-lesion preferred direction (contralateral to lesioned side) was more frequently encountered on days 7 and 30 after lesioning, as compared to days 14 and 21. The contralateral rotation observed on day 7 is attributed to degeneration-induced DA release, whereas contralateral rotation noted on day 30 is believed to reflect the operation of post-lesion compensatory processes within the spared DA neurons. In response to subsequent amphetamine administration 30 days after lesioning, rats with previous exposure to the drug circled ipsilaterally, whereas most rats given amphetamine for the first time in that session rotated contralaterally to the lesion. These findings suggest that post-lesion administration of amphetamine interferes with the process of recovery.

Animals↗
PubMed1986

Psychiatric inpatient treatment of childhood schizoaffective disorder.

Psychiatric inpatient treatment of a child with multiple life-threatening symptoms, including suicidal behavior and food refusal, is described. Changes in symptomatology were monitored by applying research scales and research interview methods during the course of intervention. The process that led to the diagnosis of childhood schizoaffective disorder is discussed.

Anger↗
PubMed1986

Sonographic assessment of the endometrium in patients undergoing in vitro fertilization.

Sonography has an important role in the care of infertile patients undergoing in vitro fertilization. Unlike the ovarian follicle, sonographic changes in the endometrium during induction have not been extensively investigated. To determine whether changes in endometrial thickness or changes in endometrial texture would predict subsequent pregnancy, a randomized, double-blind review of 320 studies was performed. None of the endometrial patterns nor any particular change from one pattern to another during induction was predictive of subsequent pregnancy. Although differences in endometrial thickness between non-pregnant and subsequently pregnant patients were noted, on an individual basis, endometrial thickness was not a useful predictor.

Double-Blind Method↗
PubMed1985

Kindling of dopaminergic pathways modifies the effect of substantia nigra lesions on rotational behaviour.

Recent studies in rats have implicated a crossed nigrostriatal (NS) pathway in the behavioural recovery that may follow unilateral lesions of the substantia nigra pars compacta (SNc). In the present study, cerebral dominance was determined from the rat's preferred direction of amphetamine-induced rotation. The ventral mesencephalic area giving rise to the crossed nigrostriatal pathway was then kindled either in the dominant hemisphere (in half of the rats), or in the non-dominant hemisphere (in the rest). All rats were then given 6-hydroxydopamine lesions in the lateral portion of the SNc on the dominant side. In control groups, the kindling procedure or electrode implantation was omitted. Neither kindling alone nor the lesion alone was found to alter the direction of amphetamine-induced rotation. In combination, however, kindling in the dominant hemisphere followed by lesioning of the lateral SNc in the dominant hemisphere caused a significant shift in the direction of rotation. This finding can be interpreted in terms of a long-term potentiation of the crossed nigrostriatal pathway after kindling. It is suggested that partial deafferentation of the neostriatum in the dominant hemisphere, combined with enhanced cross-innervation of the contralateral system, led to a shift of cerebral dominance to the intact side.

Animals↗
PubMed1985

Pattern-reversal visual evoked potentials in rabbits are resistant to occlusion of the carotid artery.

Contrast (pattern-reversal) visual evoked potentials (VEPs) were examined in the awake rabbit to test the possibility that carotid occlusion would disrupt sensory transmission in the visual pathways. Rabbits were operated to ligate one carotid and to chronically transplant another one into a skin flap. VEPs to checkerboard stimuli reversing with a rate of 2/s were recorded from the visual cortex. No significant changes in latency, amplitude and waveshape of VEPs were noted after 3-30 min of carotid occlusion. Apparently, blood flow from the basilar system can be easily shunted via the circle of Willis to the territory of the internal carotid.

Animals↗
PubMed1985

Hemispheric disconnection and rotational behaviour.

Several studies have demonstrated the existence of crossed pathways interconnecting the bilateral extrapyramidal system. The present study has evaluated the role of the thalamus in the interhemispheric control of nigrostriatal function by observing the effect of midsagittal thalamic transection on amphetamine-induced rotation in rats. The effect of thalamic transection on net rotational asymmetry did not differ from the effects of sham operations. Also, the transection did not affect the rotational asymmetry induced by subsequent lesioning of the dominant hemisphere substantia nigra. The failure to affect the rotation asymmetry by the transection suggests either that the inter-hemispheric pathway does not control extrapyramidal asymmetry or that the crossing takes place outside the thalamus. In an additional group of rats, thalamic transection did not interrupt retrograde labeling of somata in the substantia nigra and ventral tegmental area by horseradish peroxidase injected in the contralateral caudate. Thus, the crossed nigrostriatal projection does not decussate via the thalamus. It is suggested that this pathway decussates in the ventral mesencephalon.

Amphetamine↗
PubMed1985

The human tail: a benign stigma. Case report.

Thirty-three cases of true human tails have been reported in the modern English literature. A new case is described and its radiological and pathological features are presented. A review of the literature and analysis of the pathological characteristics of this interesting lumbosacral stigma indicate that the true human tail is a benign condition not associated with any underlying cord malformation.

Humans↗
PubMed1984

CT imaging of the unusually shaped bladder.

In the CT evaluation of a cystic pelvic mass it is important to identify the urinary bladder and assess its relationship to the mass. Although this is generally an easy task, we have encountered cases where delayed opacification of the bladder created diagnostic difficulties. Following intravenous contrast medium infusion, patients with normal renal function may have unopacified bladders due to (a) delayed transit from kidney to bladder and (b) rapid CT imaging of the bladder before opacification can occur. If one is aware of these problems, diagnostic dilemmas may be reduced by obtaining delayed scans of the pelvis or by obtaining postvoid films. Two cases are presented to illustrate these points.

Aged↗
PubMed1984

MR imaging of cerebral abnormalities in utero.

In view of the lack of ionizing radiation, ability to image in a variety of planes, and high contrast resolution, magnetic resonance (MR) imaging may have a role in obstetrical management. Three fetuses with severe cerebral abnormalities were studied by MR in utero. The findings were correlated with ultrasound examinations and with autopsy results. Ventricular dilatation and progression of hydrocephalus were detected by MR. Although fetal motion may affect image quality, diagnostically useful images were obtained with imaging times of 2.5 min.

Autopsy↗
PubMed1983

Amygdala kindling in the classical conditioning paradigm.

The hypothesis was tested that epileptiform alterations of brain excitability may be elicited by a conditioning stimulus (CS) in a classical conditioning paradigm. Fifteen male albino rats were chronically implanted with electrodes in the amygdala and over the visual cortex. A train of six stroboscopic flashes served as the CS and the unconditioned stimulus was the amygdaloid electrical stimulation, delivered together with the sixth flash in the course of the kindling procedure. Rats were randomly assigned to two groups. Rats in Group 1 were exposed to one or two kindling sessions per day, and those in Group 2 were exposed to 10 such sessions every day. All rats in Group 1 showed fully mature seizures within 15 +/- 5.5 sessions, whereas none of those in Group 2 displayed kindled seizures. There was no evidence of amygdaloid afterdischarges or enhanced spiking as a response to the CS. A gradual selective suppression of the visual evoked potentials (VEP) secondary components, i.e., slow negative wave and sensory afterdischarge, paralleled kindling in Group 1. This effect was weak in Group 2. There was no change in the primary response of VEPs in either group. No recovery of VEPs followed the extinction of conditioning.

Amygdala↗
PubMed1982

Left hemisphere hyperactivity in schizophrenia: abnormality inherent to psychosis or neuroleptic side-effects?

Studies measuring reflective lateral eye movements (LEM) in schizophrenic patients revealed predominance of rightward LEMS, which was interpreted as suggesting left hemisphere overactivation in schizophrenia. In the present study LEM behaviour of medicated schizophrenics was compared to that of non-medicated patients. Rightward LEMs were predominant in a group of patients treated with phenothiazines with piperazine side chains, whereas among schizophrenics treated with non-piperazine drugs leftward LEMs were more predominant. This finding suggests that previous reports on LEM directionality in schizophrenia may have been confounded by neuroleptic medication. The possible effect of piperazine derivatives on hemispheric balance is discussed.

Adult↗
PubMed1982

Unilateral dopamine deficit and lateral eeg asymmetry: sleep abnormalities in hemi-Parkinson's patients.

The hypothesis was tested that unilateral dopamine deficiency leading to the contralateral extrapyramidal syndrome (hemi-parkinsonism) would cause distinctly asymmetric EEG sleep patterns. In 7 hemi-Parkinson's patients 2 nights of sleep were monitored along with pre-sleep waking periods. No medication was given prior to the first night. The second night followed at least 2 months of L-DOPA medication. Although in all patients sleep architecture was disturbed, no statistically significant asymmetries of sleep patterns were obtained. L-DOPA medication improved the quality of sleep. Delta sleep was most visibly improved. Also, post-treatment enhancement of the mean delta power over the parkinsonian hemisphere was supported statistically. The role of dopamine in slow wave sleep control and mechanisms of contralateral hemisphere involvement are discussed.

Aged↗
PubMed1982

A comparison of levodopa treatment and task demands on visual evoked potentials in hemi-parkinsonism.

In patients with hemi-Parkinsonism the amplitude of visual evoked potential (EP) components was relatively reduced over the hemisphere contralateral to Parkinsonian symptomatology. Chronic levodopa treatment tended to reverse this lateral asymmetry. Before levodopa treatment, participation in a simple attentional task brought about similar EP changes. After levodopa treatment, only patients with left symptomatology responded to the attention task with an enlargement of EP components, largely in the noninvolved hemisphere. These findings suggest that task demands cause changes in the sensory system which are similar to those contributing to "paradoxical kinesia."

Adult↗
PubMed1982

Neuroleptic-induced lateral asymmetry of visual evoked potentials in schizophrenia.

Electrophysiological studies have shown asymmetric brain reactivity in schizophrenia, supporting the hypothesis of left hemisphere hyperarousal in this disease. It may be assumed, therefore, that neuroleptic treatment restores hemispheric balance in schizophrenic patients by selectively suppressing the hyperactive left hemisphere. This hypothesis was tested in the present study which compared bilaterally recorded visual evoked potentials (VEP) in 9 non-medicated patients and 29 schizophrenics treated with various neuroleptic drugs, as well as in 34 normal controls. In medicated patients later VEP components showed enhancement over the right hemisphere as a function of the overall dose (chlorpromazine equivalent) of neuroleptics. Reversed asymmetry was seen in drug-free patients. In view of this result, some amendments of the concept of left hemisphere hyperactivity in schizophrenia are proposed.

Adolescent↗