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Biomedical subjects

M Hadani

Publications and source records attributed to M Hadani.

At least 55 records · Page 3Linked to original sources
PubMed1991

Vasospasm due to massive subarachnoid haemorrhage--a rat model.

Although the pathophysiology of chronic cerebral vasospasm following subarachnoid haemorrhage (SAH) is still unclear, it is certain that the amount of subarachnoid blood is predictive of the severity of cerebral vasospasm. Accordingly, massive subarachnoid haemorrhage (greater than 0.5 ml) was induced in adult rats via direct injection into the cisterna magna. Compared to other previously published models of experimental SAH in rats a much larger amount of blood was injected. The basilar artery was exposed 72 hours post subarachnoid haemorrhage and photographed under controlled conditions. The diameter of the artery was assessed by an image analyzer. A 50% reduction in diameter was found in 25 rats subjected to SAH as compared to 9 control rats and 4 rats with intracisternal saline injection. We conclude that when massive subarachnoid haemorrhage is induced, and direct measurements of the basilar artery are made, the rat can be used as a reliable model for investigation of SAH induced arterial vasospasm.

Animals↗
PubMed1991

Magnesium sulfate reverses experimental delayed cerebral vasospasm after subarachnoid hemorrhage in rats.

We induced experimental delayed cerebral vasospasm by the intracisternal injection of greater than 0.5 ml blood in 30 rats. Seventy-two hours later the basilar artery was exposed via the transclival approach and photographed at high-power magnification through an operating microscope. We then evaluated the effect of topical (n = 30) and intravenous (n = 20) magnesium sulfate on the spastic artery by computerized image analysis. A greater than 50% reduction in baseline diameter of the basilar artery was observed in the rats subjected to subarachnoid hemorrhage compared with the 10 controls (p less than 0.0001). Intravenous magnesium sulfate dilated the spastic artery to approximately 75% of the baseline diameter in control rats (p less than 0.0001). Topical magnesium sulfate caused dramatic dilation of the basilar artery in both the control and the subarachnoid hemorrhage groups to near 150% of the baseline diameter in the controls (p less than 0.001). All rats receiving intravenous magnesium sulfate reached therapeutic plasma levels of the ion. Hemodynamic effects were mild and immediately reversible upon cessation of magnesium sulfate administration. We suggest that magnesium has a role in the treatment of subarachnoid hemorrhage-induced vasospasm in humans.

Animals↗
PubMed1989

Intratumoural cyst formation in pituitary macroadenomas.

Twenty-one patients with various types of pituitary macroadenomas underwent hypophysectomy at the Chaim Sheba Medical Centre between 1985 to 1987. Intraoperative fine needle aspiration of the tumoural content was attempted prior to tumour excision. Although none of the patients had a history compatible with pituitary apoplexy, intratumoural fluid suggestive of a cyst within the tumour was found in 57% of the patients. Analysis of the hormones in the aspirated fluid revealed variable elevations in hormone levels, some reaching 3,000 times the equivalent plasma levels. Concomitant elevated levels of other pituitary hormones found in the cyst fluid support the concept of mixed secretory potential of pituitary adenomas, including the apparently non-functioning tumours. Six out of seven patients (86%) who received preoperative treatment with bromocriptine had an intratumoural cyst while only seven out of fourteen patients (50%) who were not treated with this drug prior to surgery had a cyst within the tumour. The implications of these observations on current theories concerning the pathophysiology of pituitary adenomas are discussed.

Adenoma↗
PubMed1989

Upward transtentorial herniation: a complication of postoperative edema at the cervicomedullary junction.

Local edema at the operative bed developed a few hours after uneventful subtotal removal of a lesion occupying the lower medulla and upper cervical cord. The patient experienced apnea, quadriplegia, and circulatory collapse followed by acute respiratory insufficiency. Hydrocephalus secondary to aqueductal occlusion occurred on the 3rd postoperative day. A computerized tomographic scan was compatible with upward transtentorial herniation. The association of this phenomenon with an intra-axial lesion at the cervicomedullary junction has not been previously documented. The pathophysiological mechanisms implicated in this complication are discussed.

Adult↗
PubMed1989

Delayed postoperative neurological deterioration from prolonged sodium nitroprusside administration. Case report.

Sodium nitroprusside is commonly used for the induction of hypotension during neurosurgical procedures. Its toxicity stems from hemodynamic compromise as well as from its metabolites, especially the formation of cyanide. A patient is described who underwent craniotomy for hypertensive intracerebral hemorrhage. He gradually recovered following the operation, but needed continued administration of sodium nitroprusside for control of hypertension. On the 7th postoperative day, he deteriorated into coma with evidence of severe edema and herniation on the computerized tomography scan. Cessation of sodium nitroprusside and treatment for cyanide poisoning resulted in resolution of his symptoms within hours. The potential toxicity of sodium nitroprusside, measures to prevent toxicity, and therapeutic steps are discussed.

Brain Edema↗
PubMed1989

Delayed nonhemorrhagic encephalopathy following mild head trauma. Case report.

Delayed nonhemorrhagic encephalopathy following mild head trauma is a rare condition with an unknown etiology. The few cases reported in the literature are in young adults, all of them in the era before computerized tomography (CT) became available, and all had a devastating clinical course with multifocal ischemia or necrotic lesions found at autopsy. A case is presented of a young man with this syndrome who survived the acute encephalopathic phase with severe residual neurological deficits. Repeat CT scans during and following the acute phase as well as magnetic resonance imaging showed diffuse multifocal lesions compatible with ischemic changes and demyelination in the "watershed" areas of the brain.

Adult↗
PubMed1988

Nicardipine reduces calcium accumulation and electrolyte derangements in regional cerebral ischemia in rats.

We studied the effects of the calcium channel blocker nicardipine on regional tissue Ca2+, Na+, K+, and water shifts in the brains of seven Sprague-Dawley rats after permanent occlusions of the middle cerebral artery. We also assessed the entry of [14C]nicardipine into the brains of five rats; the highest concentrations of [14C]nicardipine were in the infarcted area. Nicardipine treatment significantly reduced Ca2+ accumulation in the middle cerebral artery territory by 60% compared with six untreated rats 6 hours after arterial occlusion. Eight 125-micrograms/kg boluses of nicardipine given every 30 minutes starting 5 minutes after arterial occlusion also significantly reduced the Na+ and K+ shifts in the middle cerebral artery territory by 40% and 50%, respectively, 6 hours after arterial occlusion. Nicardipine appears to reduce Ca2+ accumulation more than it reduces Na+ and water accumulation and K+ loss. Our results suggest that a calcium channel blocker can protect brain tissues in a model of focal cerebral infarction by directly reducing Ca2+ entry into ischemic cells.

Animals↗
PubMed1986

Tissue Na, K, and Ca changes in regional cerebral ischemia: their measurement and interpretation.

A simple and reliable method of quantifying tissue damage is described. This method, based on atomic absorption spectroscopic determinations of Na, K, and Ca concentrations in small brain samples, was applied to the rat middle cerebral artery occlusion model (MCAo). At the infarct site by 24 hours, Na concentration more than doubled, Ca concentration increased by greater than 70%, and K concentration fell nearly 80%; these changes are consistent with a greater than 80% disruption of cells. A remarkable acceleration of ionic shifts occurred between 4 and 6 hours after MCAo. At 4 hours, only 20-30% of the ionic shifts found at 24 hours had occurred; by 6 hours, 80-100% of the ionic shifts found at 24 hours had taken place. Since the measurements reflect ionic movement into and out of the tissue, they are likely to represent irreversible tissue damage. Although blood brain barrier breakdown may have contributed to an increased rate of ionic shifts, large ionic gradients must have been present between the extracellular space and the vascular compartment at 4-6 hours to drive the ionic shifts. Our results suggest an upper time limit of 4 hours for treatments of acute ischemic tissue damage in the rat MCAo model. The methods and analytical approach described may be useful for determining the time window for therapeutic intervention in acute CNS injuries, as well as for evaluating treatment effects.

Acute Disease↗
PubMed1986

Entrapped lumbar nerve root in pseudomeningocele after laminectomy: report of three cases.

The authors report three patients with symptomatic postlaminectomy pseudomeningocele. At operation a loop of a nerve root was found to be trapped within the dural defect. All three patients exhibited a delayed onset of radicular symptoms and signs after disc surgery. The pseudomeningocele was demonstrated computed tomography and myelography, but the entrapped root could be identified only at operation.

Adult↗
PubMed1985

Regenerating fish optic nerves and a regeneration-like response in injured optic nerves of adult rabbits.

Regeneration of fish optic nerve (representing regenerative central nervous system) was accompanied by increased activity of regeneration-triggering factors produced by nonneuronal cells. A graft of regenerating fish optic nerve, or a "wrap-around" implant containing medium conditioned by it, induced a response associated with regeneration in injured optic nerves of adult rabbits (representing a nonregenerative central nervous system). This response was manifested by an increase of general protein synthesis and of selective polypeptides in the retinas and by the ability of the retina to sprout in culture.

Animals↗
PubMed1985

A new transorbital surgical approach to the rabbit's optic nerve.

This work describes a surgical approach which establishes the rabbit's visual system as an experimental model for studying CNS regeneration. Using this model, the optic nerve, its cell bodies, and the axons, are easily accessible through an orbital approach, without the need for craniotomy and brain retraction. This surgical approach allows transplantation and 'wrap around' implantations of nerve segments from xenogeneic and syngeneic systems and diffusible substances derived from them, respectively. Furthermore, it enables studies aimed at determining deficiencies in mammalian CNS and investigating methods of augmentating mammalian CNS regeneration.

Animals↗
PubMed1985

Spinal intradural ependymal cyst: a case report and review of the literature.

Spinal intradural ependymal cysts are extremely rare. The case presented is the sixth reported in the literature. The symptoms are consistent clinically and radiologically with a spinal intradural space-occupying lesion. The cyst wall is lined with both ciliated and nonciliated cells, resting directly on connective tissue. The exact embryonal origin of these cysts is obscure.

Child↗
PubMed1985

Unusual delayed onset of diabetes insipidus following closed head trauma. Case report.

A case of delayed onset of diabetes insipidus (DI), which developed 27 days after a closed head injury, is reported. The patient sustained only a minor neurological deficit and, except for antidiuretic hormone (ADH) insufficiency, hypothalamic function was intact. This selective damage of posterior pituitary function was total and permanent. Ischemia due to vascular injury may be the most likely etiology. Once the diagnosis of delayed posttraumatic DI is confirmed, the treatment of choice is DDAVP (desmopressin acetate). In contradistinction to DI immediately following minor head injury, most patients with a delayed onset of DI after trauma have permanent ADH deficiency.

Adolescent↗
PubMed1984

Substances originating from the optic nerve of neonatal rabbit induce regeneration-associated response in the injured optic nerve of adult rabbit.

We have recently shown that cell bodies of an injured optic nerve of adult rabbit can be induced to express regeneration-associated response by external signals derived from nonneuronal cells of regenerating nerves of lower vertebrates. In this study it is shown that even substances derived from a nonregenerating mammalian system also can trigger such a regenerative response. Thus, substances derived from intact nerves of neonatal rabbits and of adult rabbits, to a lesser extent, were active in triggering a regeneration-associated response, whereas substances derived from injured nerves of adult rabbit were not. However, if subsequent to the injury the nerve was implanted with silicone tube containing medium conditioned by neonatal optic nerves, the substances derived from the implanted injured nerve were active. Thus, it appears that the ability of a periaxonal environment to provide triggering substances correlates with axonal growth. Therefore, we named these substances "growth-associated triggering factors" (GATFs). It is suggested that mammalian cells are unable to express a regenerative response after an injury due to the failure of their nonneuronal cells to produce regeneration-triggering substances. This disability may be circumvented by an appropriate implantation procedure.

Aging↗
PubMed1983

Long-term barbiturate infusion to reduce intracranial pressure.

We report two cases of children, 7 and 14 yr old, in whom prolonged infusion of thiopental sodium (TS) was used to control intracranial hypertension previously unresponsive to conventional therapy. Intracranial hypertension followed removal of a large tumor in 1 case, and trauma in the other. TS was administered at a rate of up to 7 mg/kg . h for 8 days in 1 patient, and up to 12 mg/kg . h for 10 days in the other. Both children regained consciousness and made significant recovery of neurological function. The advantage and the side-effects of the prolonged use of TS for intracranial hypertension are discussed.

Adolescent↗