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Biomedical subjects

J Israeli

Publications and source records attributed to J Israeli.

At least 19 recordsLinked to original sources
PubMed1994

Organ-localized hypothalamic-stimulated vasculature changes in the cat.

Stimulation of specific lateral hypothalamic targets in a cat model induces vascular and/or cardiac changes. Evidence is presented that these may consist of discretely localized sympathetically mediated changes taking place in just one or two organs. Moreover, following stimulation of either one of two adjacent lateral hypothalamus sites, pressor effects are induced that superficially look similar, but prove to be mediated by different pathways. To investigate possible synapsing at sympathetic ganglia, e.g. in superior cervical or stellate ganglia, 50 micrograms atropine methyl nitrate, a ganglionic blocker, was applied directly to the ganglia. This was shown to potentiate the pressor effects, in some cases when applied to the superior cervical ganglia, in others to stellate ganglia, presumably by blockade of a ganglionic attenuating mechanism. The contributions made by different sympathetic nerves to the lateral hypothalamus-induced pressor effect were analysed. Stimulation of one of the lateral hypothalamus sites (TAR.I) in eight cats induced a pressor effect that was abolished by severing a nerve branch, from the superior cervical ganglia laterally, shown to innervate neck muscle vasculature. In another group of nine cats stimulation of TAR.II induced a pressor effect abolished by cutting a branch from the superior cervical ganglia medially, shown to be destined to the vasculature of pharyngeal muscles and possibly lower respiratory tract. The hypothesis that central control via the sympathetic nervous system is responsible for differential organ specific regulation of blood flow to individual organs is discussed.

Animals↗
PubMed1989

Depressor effects of muscarinic and non-muscarinic mediation induced by lateral hypothalamic stimulation in the cat.

Transient sympathetically-mediated depressor effects were induced by stimulation of a small locus in the lateral hypothalamic peri-fornical region, medial to the fields of Forel. The ganglionic blocking agent, atropine methyl nitrate (ATMN), was used to show that muscarinic as well as non-muscarinic sympathetic ganglion receptor neurotransmission was involved. Evidence is presented that stimulation of this LH site co-activates a number of mechanisms and that depending on which of these are activated, the ganglionic blocking agent ATMN may either block, reverse or potentiate the depressor effect.

Animals↗
PubMed1987

Sympatho-inhibitory mechanisms acting at sympathetic ganglia to attenuate hypothalamic-induced pressor effect in the cat.

Pressor and tachycardic effects induced in the cat by stimulation of a lateral hypothalamic (LH) site, are shown to be mediated by sympathetic ganglia nicotinic receptor, and potentiated under atropine methyl nitrate sympathetic ganglia blockage. It is postulated that a sympatho-inhibitory pathway muscarinic ganglionic mechanism, co-activated by the LH stimulation, attenuates the pressor and tachycardic effects, the potentiation presumably being a manifestation of blockage of that mechanism.

Animals↗
PubMed1983

Oxytocin antagonism of hypothalamic-induced angina-like ECG changes and pressor effects in the cat.

Electrical stimulation of a specific site in the lateral hypothalamus of the cat, in a region posterior to Hess' defense area, results in pressor effects and angina-like ECG changes which consist either of T-wave inversion and ST-segment prolongation or in the appearance of tall T-waves. Oxytocin (10 U, i.v.) administered 15 min prior to stimulation, prevents the former ECG changes and BP rise in 90%, and the latter ECG changes and BP rise in 50% of the animals.

Angina Pectoris↗
PubMed1983

A pharmacological analysis of autonomic pathways mediating myocardial disturbances originating in a lateral hypothalamic area of the cat.

A study was made of the mechanisms mediating autonomic changes resulting from stimulation of a site in the lateral hypothalamic area (LHA). This site, when stimulated, induced angina-like ECG disturbances similar to those observed in some cases of brain traumas. These ECG changes were often associated with other autonomic changes, such as pressor response, tachycardia (in some cases bradycardia), nictitating membrane (NM) contraction and pupillary dilatation. Most symptoms were sympathetic: they were largely abolished by spinal cord section between C1 and C2, but were not affected by vagotomy, except that bradycardia was converted to tachycardia. Adrenal catecholamines were not involved since adrenal vein ligation was without effect. Hexamethonium (5-10 mg/kg) prevented pressor response and tachycardia in most cats but only partly protected against ECG changes and NM contractions. Atropine methyl nitrate (0.2 mg/kg) abolished the remaining ECG abnormalities and NM tension. The beta-receptor antagonists, propranolol and practolol (50 micrograms/kg) completely prevented the ECG changes induced either by isoprenaline or LHA stimulation. It is concluded that the symptoms induced by LHA stimulation result from noradrenaline release in the target organs.

Angina Pectoris↗
PubMed1983

Multicentric gliomas of brain and spinal cord.

The clinical and histopathological findings in a child suffering from both cerebral and spinal gliomas of differing histological types are described. There was a family history of von Recklinghausen's neurofibromatosis. The possibility of overlooking the symptoms and signs pointing to a spinal cord lesion in the presence of a known intracranial tumour is stressed.

Brain Neoplasms↗
PubMed1983

Stereotaxic head restraint for chronic and semi-chronic marmoset and macaque monkeys.

A device allowing head holding and stereotaxic manipulations in both small-sized Marmoset and in relatively large Macaca monkeys is described. Its design permits free access to most targets in the visual system and optimizes presentation of visual stimuli in awake-chronic and anaesthetized semi-chronic preparations. Extra-aural attachments to temporal bone are implanted stereotaxically, under anaesthesia, on both sides of the skull. This provides means for stereotaxic head-holding which minimizes discomfort to the animal. Maintenance of stereotaxic precision over long periods of time, possibility of realignment and use of one device for various monkey species are special features of the method.

Animals↗
PubMed1983

Successful removal of an acute brain stem hematoma in a young child.

Several days after receiving a blow to the occipital region, a 5-year-old boy presented with acute symptoms and signs of a space-occupying-lesion in the posterior fossa. A CAT scan revealed a mass with increased density in the region of the fourth ventricle. A suboccipital craniectomy disclosed a subependymal hematoma bulging into the fourth ventricle. The hematoma was evacuated, and the child subsequently made a complete recovery. It is stressed that surgical intervention should be considered in all such cases and particularly in young patients who show progressive neurological deficits.

Brain Stem↗
PubMed1982

Angina-like cardiac disturbances of hypothalamic etiology in cat, monkey, and man.

Angina-like phenomena of CNS etiology were studied. Data were collected and analyzed from clinical cases of cerebral hematoma, concussion, and tumors in which cardiological disturbances were observed consequent to compressive brain lesions or surgical brain manipulations. The cases in which the disturbances were largely angina-like and without ectopic beats or arrhythmias were chosen for study. The brain region most significantly related to this phenomenon seemed to be the hypothalamus. Experiments conducted in cats and monkeys showed that stimulation of specific sites in the hypothalamus resulted in angina-like manifestations with no other cardiac changes. These data support our working hypothesis that a cerebrally induced syndrome that is conspicuously angina-like must be related to hypothalamic involvement. In the awake monkey hypothalamic stimulation caused angina-like ECG changes and behavior suggestive of referred pain. In some cases, repetitions of the stimulations or irritations in all of the species resulted in permanent pathological myocardial changes, mostly bleeding into the myocardium. In some animals there were minute hemorrhagic necroses that were subepicardial in distribution. It is significant that the most severe or permanent pathological changes were found in cases in which the angina-like ECG alterations were persistent. There were also cases, however, with persistent angina-like ECG changes that showed no such pathology.

Adolescent↗
PubMed1981

Surgical treatment of spinal meningiomas.

A review is presented of 44 cases of spinal meningioma. Analyses of the data collected indicated that early diagnosis may prevent irreversible neurological deficit and enhances the chance for full recovery after operation. The results obtained in elderly patients were very encouraging. The difficulties involved in making a correct early diagnosis are stressed. The finding of scoliosis in 40 per cent of the patients is noteworthy.

Adult↗
PubMed1976

Malignant optic glioma in a 70-year-old patient.

In a 70-year-old man with glioma of the optic nerves and tracts, the initial symptom was a unilateral loss of vision that progressed rapidly and was followed by amaurosis of both eyes. All diagnostic radiological procedures were negative. Four months after the onset of the disease, the patient developed hemiplegia, became comatose, and died. Post-mortem examination revealed a glioblastoma multiforme of both optic nerves, chiasma, and optic tracts that extended posteriorly into the left thalamus and medial geniculate body. The tumoral thickening of the optic nerves was absent in the intracanalicular part, a finding that concurred with the normal radiological appearance of the optic foramen. Glioblastoma multiforme of the optic pathways should be included in the differential diagnosis of acute visual failure in elderly people, even though the final diagnosis may be possible only at postmortem examination.

Aged↗