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Biomedical subjects

B S Zaret

Publications and source records attributed to B S Zaret.

8 recordsLinked to original sources
PubMed1991

Circumscribed midline EEG activity in neurologically normal neonates.

Activity occurring predominantly at or circumscribed to the midline electrodes Fz, Cz and Pz was examined in 18 neurologically normal neonates of 27-42 weeks conceptional age (CA). Admixtures of delta and beta activity, which sometimes resembled delta brushes and rhythmical theta activity, of less than three seconds duration were seen during the suppressed portions of tracé alternant or discontinue quiet sleep in 27-32 week CA neonates. Single sharp midline waves, or entrained 4-8 Hz midline activity of 3 seconds or less duration, were found in preterm neonates (33-36.5 weeks CA) only in quiet sleep, whereas these phenomena were also present in active sleep in term (38.5-42 weeks CA) infants. Midline alpha activity with a duration less than or equal to 3 seconds was found initially in quiet sleep in the 33-36.5 week CA infants and then exclusively in active sleep in the term infants. These data consolidate and refine the existing literature on normal neonatal midline activity through the identification of the temporal and topographical characteristics of a spectrum of normal activity in infants of 32 weeks CA and older.

Electroencephalography↗
PubMed1988

Hepatic and renal contributions to valproic acid-induced hyperammonemia.

Valproic acid (VPA) consistently and reproducibly elevates arterial ammonia in rats injected with an amino acid load. The extent of the hyperammonemia is dependent on the dose of VPA injected or VPA plasma concentration and the amino acid dose. Bilaterally nephrectomized rats injected with VPA and an amino acid load also develop hyperammonemia, which overall approximates 75% of that achieved in non-nephrectomized animals. In non-nephrectomized animals injected with an amino acid load, valproic acid produces a marked reduction in baseline and activated hepatic mitochondrial carbamyl phosphate synthetase I activity. Our results suggest that VPA-induced hyperammonemia after an amino acid load results from inhibition of hepatic intramitochondrial citrullinogenesis with only a limited contribution from the kidneys.

Amino Acids↗
PubMed1985

Prognostic and neurophysiological implications of concurrent burst suppression and alpha patterns in the EEG of post-anoxic coma.

Concurrent burst suppression and alpha pattern coma developed in the EEG of a 2-year-old child who suffered a cardiac arrest secondary to hypoxemia from Haemophilus influenza epiglottis. The neurophysiological implications of this association are discussed and the literature pertaining to the role of barbiturates in the production of post-anoxic coma with an alpha pattern and experimental post-resuscitative alpha frequencies is reviewed.

Airway Obstruction↗
PubMed1985

Lightning streaks of Moore: a cause of recurrent stereotypic visual disturbance.

Lightning streaks of Moore are recurrent stereotypic vertical visual phenomena that must be distinguished from similar symptoms due to retinal ischemia, optic disk abnormalities, or mechanical retinal or optic nerve stimulation. These brief flashes are oriented vertically and are perceived in the temporal visual field after eye movement. Senescent posterior vitreous changes induce collapse and detachment with persistent vitreoretinal adhesions through which mechanical forces exert traction on the macula and retina, inducing photopsias. Clinical recognition of these symptoms avoids unnecessary diagnostic interventions.

Aged↗
PubMed1982

Sodium valproate-induced hyperammonemia without clinical hepatic dysfunction.

Three adults on unrestricted protein diets receiving valproic aci (VPA) developed gastrointestinal symptoms with encephalopathy and/or deteriorating seizure control associated with arterial hyperammonemia and normal liver function tests. The signs and symptoms did not directly correlate with VPA dosage and the arterial ammonium levels did not correlate with serum VPA concentrations. Two of the three patients had phenobarbital concentrations above the therapeutic range, but remission of neurologic or gastrointestinal symptoms was dependent on a reduction of the VPA concentration. In one case, rechallenge with VPA reproduced hyperammonemia.

Adult↗
PubMedDate not supplied

Reversible valproic acid-induced dementia: a case report.

Reversible valproic acid-induced dementia was documented in a 21-year-old man with epilepsy who had a 3-year history of insidious progressive decline in global cognitive abilities documented by serial neuropsychological studies. Repeat neuropsychological testing 7 weeks after discontinuation of the drug revealed dramatic improvement in IQ, memory, naming, and other tasks commensurate with clinical recovery in his intellectual capacity. Possible pathophysiological mechanisms which may have been operative in this case include: a direct central nervous system (CNS) toxic effect of valproic acid; a paradoxical epileptogenic effect secondary to the drug; and an indirect CNS toxic effect mediated through valproic acid-induced hyperammonemia.

Adult↗