Biomedical subjects
Publications and source records attributed to M Sadeh.
Cogan's syndrome, nonsyphilitic interstitial keratitis with vestibuloauditory dysfunction, is an uncommon disease of young adults, probably a manifestation of vasculitis. A 32 year old woman with this syndrome developed a thalamic syndrome with amnesia and dysphasia due to lacunar infarcts.
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.
In two patients with carotid artery stenosis and anemia, neurological deficits appeared whenever the hemoglobin level fell below a critical level of 5-6 g/dl and resolved with correction of the anemia. Profound anemia should be considered as a cause of focal neurological deficit, especially if there is evidence of cerebral atherosclerosis.
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Fourteen Jewish patients from 10 families of either Iraqi or Iranian origin with congenital myasthenia had associated facial malformations which included an elongated face, mandibular prognathism with class III malocclusion and a high-arched palate. Other common features were muscle weakness restricted predominantly to ptosis, weakness of facial and masticatory muscles, and fatigable speech; mild and nonprogressive course; response to cholinesterase inhibitors; absence of antibodies to acetylcholine receptor; decremental response on repetitive stimulation at 3 Hz but no repetitive compound muscle action potential in response to a single nerve stimulus. This newly recognized form of congenital myasthenia with distinctive ethnic clustering and associated facial malformations is transmitted as an autosomal recessive disorder. The facial abnormalities may be secondary to the neuromuscular defect or may be primary and unrelated. Further studies are needed to elucidate the defect in neuromuscular transmission responsible for the pathogenesis of this syndrome.
A father and son with muscular hypertrophy, stiffness and myoedema are described. The local swelling after tapping the muscle was not accompanied by electrical activity. Histological and histochemical studies of muscle biopsy showed no abnormalities. Electron-microscopy showed multiple vacuoles to be due to T-tubule dilatation. Further studies are necessary to determine the significance of this finding in the pathogenesis of muscle sensitivity to mechanical irritation in this rare syndrome.
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Six patients with carnitine palmitoyltransferase (CPT) deficiency were diagnosed. Five were males aged 12-48 years and one was a 7-year-old girl. Severe myoglobinuria with renal shut-down led to the diagnosis in four, the main cause of myoglobinuria being prolonged exertion. Other precipitating factors included febrile illnesses, fasting and sleep deprivation. Between attacks, EMG, serum creatine kinase (CK) activity and the response of serum lactate to ischemic exercise were normal in all patients. The diagnosis of CPT deficiency was based on assay of the enzyme by the isotope exchange assay in leukocyte, muscle or cultured skin fibroblast homogenates. CPT activity assayed by the forward assay under standard conditions was normal. CPT deficiency seems to be a common cause of exercise-induced myoglobinuria. Prompt diagnosis can lead to avoidance of risk factors and prevention of rhabdomyolysis and its consequences.
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An awake patient presented with central neurogenic hyperventilation induced by a cerebral tumor. Corticosteroid therapy and brain irradiation while the patient was anesthetized and respiration controlled under pancuronium-induced respiratory paralysis were followed by tumor regression and resolution of hyperventilation. Recurrence of tumor 6 weeks later was not accompanied by recurrence of hyperventilation. Cytologic study of cerebrospinal fluid revealed B-cell lymphoma. This patient brings to 10 the number of cases recorded with tumor-induced central neurogenic hyperventilation. Five of the eight patients with known tumor histology had a primary cerebral lymphoma, a rare neoplasm that comprises only 1% of all intracranial neoplasms. The disproportionately high frequency of central neurogenic hyperventilation in patients with cerebral lymphoma has therapeutic implications that are briefly reviewed.
Recent evidence supports the concept that cerebral vasospasm is involved in the pathogenesis of eclampsia. Magnesium, which has a beneficial effect in eclampsia, may act by opposing calcium-dependent arterial constriction, thereby relieving vasospasm. Magnesium may also antagonize the increase in intracellular calcium concentration caused by ischemia and thus prevent cell damage and death. Magnesium might have a role in the treatment of cerebral vasospasm and ischemia, such as occurs in subarachnoid hemorrhage, ischemic stroke, and brain trauma.
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We describe a family in which the father had neurofibromatosis-1 and the mother neurofibromatosis-2. Their son presented at the age of 8 years with bilateral acoustic neuromas, meningioma, and numerous neurofibromas. We believe that the occurrence of the genes responsible for both forms of neurofibromatosis in the same patient had a synergistic effect on the early rapid growth of neurofibromatoses 1 and 2 neoplasms.
McArdle disease is reported in three generations of a consanguineous Druze family. The diagnosis was established on the basis of a failure of a rise in lactate in the ischemic forearm exercise test, glycogen accumulation in muscle fibers and the lack of myophosphorylase by histochemical and biochemical studies. The inheritance pattern is compatible with an autosomal recessive mode. Examination of family members revealed a marked variability in the clinical findings and functional status. This is the first reported case of the disorder in this ethnic group.
A number of amphiphilic and lipid-soluble drugs of heterogeneous pharmacological properties, when injected into rat anterior tibial muscles, induced acute muscle fibre necrosis. The myotoxic agents were: penicillin, cloxacillin, phenobarbital, haloperidol, diazepam, hydantoin, metoclopramide, pentazocine and chlorpromazine. The regenerative process, studied using the latter three medications, showed rapid regeneration, complete within 3 weeks. Injection of the water-soluble drugs aminophylline, tranexamic acid and vitamins B6 and B12 produced no tissue damage. The pathogenesis of muscle fibre necrosis is suggested to involve direct damage to cell membranes by lipid soluble drugs.
Proximal lower limb weakness and fasciculations were the only clinical manifestations of hexosaminidase A (Hex A) deficiency in a 39-year-old woman. Hex A activity in serum and leukocytes was 0 to 4% by standard heat inactivation fluorogenic substrate methods, and 5% when Hex A isoenzymes were fractionated by diethylaminoethanol cellulose chromatography. Computed tomography of the brain showed cerebellar atrophy. We suggest that Hex A activity studies be done in patients with typical as well as atypical spinal muscular atrophy.
Bupivacaine was injected into the anterior tibial muscles of 2-year-old rats. The induced degeneration - regeneration was slow, taking 3 weeks to completion (1 week in young rats). The reconstituted muscle showed small fiber size, an increased number of internal nuclei and longitudinal splitting. These findings may have implications for human muscular disorders and trauma in the aged.
A 70-year-old patient with bilateral vocal cord paralysis, accompanied by inspiratory stridor and increased snoring, is presented. Respiratory dysfunction, deteriorating over 18 months, necessitated permanent tracheostomy. Only two and a half years after the onset of symptoms the patient developed extrapyramidal signs combined with severe autonomic failure, suggesting a diagnosis of Shy-Drager syndrome. Vocal cord palsy preceding any other neurological or autonomic manifestations of that syndrome has been infrequently described. This diagnosis should be considered in cases of vocal cord palsy of undetermined etiology, especially when associated with increased snoring or episodes of sleep apnea.