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Biomedical subjects

S Harel

Publications and source records attributed to S Harel.

At least 91 records · Page 5Linked to original sources
PubMed1987

Fluctuating dystonia responsive to levodopa.

Four cases of hereditary progressive dystonia with diurnal fluctuation were studied. All were sporadic; three of them mimicked spastic diplegia; and the fourth showed some similarity to torsion dystonia. Emotional or cognitive disturbance, or both, was seen in three. The correct diagnosis was suggested by fluctuating signs and symptoms, which worsened towards evening, but this was reached only after many years of handicap, hospital admissions, and invasive diagnostic procedures. Typically there was a prompt, pronounced, and sustained response to moderate doses of levodopa. Sleep recordings were obtained in three patients and showed increased body movements during rapid eye movement sleep. Several close relatives had periods of increased leg movements during sleep. It is suggested that hereditary dystonia responsive to levodopa should be considered as the diagnosis in children with fluctuating signs of motor disability syndromes, simulating torsion dystonia or spastic diplegia. Polysomnographic studies may be helpful in diagnosis and may also detect early or subclinical cases.

Child↗
PubMed1987

Desferrioxamine as an electron donor. Inhibition of membranal lipid peroxidation initiated by H2O2-activated metmyoglobin and other peroxidizing systems.

Desferrioxamine (DFO) involvement in several peroxidative systems was studied. These systems included: a) membranal lipid peroxidation initiated by H2O2-activated metmyoglobin (or methemoglobin); b) phenol-red oxidation by activated metmyoglobin or horseradish peroxidase (HRP): c) beta-carotene-linoleate couple oxidation stimulated by lipoxygenase or hemin. Desferrioxamine was found to inhibit all these systems but not ferrioxamine (FO). Phenol-red oxidation by H2O2-horseradish peroxidase was inhibited competitively with DFO. Kinetic studies using the spectra changes in the Soret region of metmyoglobin suggest a mechanism by which H2O2 reacts with the iron-heme to form an intermediate of oxy-ferryl myoglobin that subsequently reacts with DFO to return the activated compound to the resting state. These activities of DFO resemble the reaction of other electron donors.

Cell Membrane↗
PubMed1986

Muscarinic binding sites in newborn brain from intrauterine growth-retarded rabbits.

Intrauterine growth retardation (IUGR) was induced in rabbits by means of vascular ligation in utero 4-6 days prior to birth. The vascular-restricted living newborns and controls from the unligated uterine horns were killed at birth and the level of the muscarinic cholinergic receptors in cerebral and cerebellar homogenates measured using the potent antagonist 3H-QNB. No significant difference in the binding sites of the cerebellum and the cerebral cortex was found between restricted and control animals. It is speculated that the ineffectiveness of the vascular insult to affect specifically muscarinic binding sites could partially be explained by the specificity of the receptors and the timing of the ischemic insult in relation to the stage of the developing brain. Other cholinergic markers should also be assessed.

Animals↗
PubMed1985

Computed tomographic demonstration of brain changes in incontinentia pigmenti.

Incontinentia pigmenti is a rare condition, which may involve the central nervous system. Computed tomographic (CT) examination can supply important information about the dynamics and pathologic nature of this poorly understood syndrome. Two patients suffering from incontinentia pigmenti were examined by CT because of central nervous system symptoms. Large low-density areas in the brain were demonstrated in the CT examination of the first patient a few days after birth, suggesting a local edema. Diffuse brain atrophy was found two years later. Brain atrophy was also found in the second patient in a CT examination done at the age of 11 years.

Atrophy↗
PubMed1985

Cerebellar astrocytoma presenting as deterioration of handwriting in a child.

Deterioration of handwriting in an 11-year-old boy over a 2 month period was found to be caused by a cerebellar astrocytoma. The clinical picture was characterised by a lack of the classic symptoms of increased intracranial pressure. The only positive neurological findings pointed to an isolated right cerebellar symptomatology expressed by mild intention tremor and decreased tone of the right hand. Progressive deterioration of handwriting can be an ominous sign and it should be known to all professionals, as a lack of awareness can cause delay in expert referral and diagnosis.

Astrocytoma↗
PubMed1985

Lipid peroxidation and oxidation of several compounds by H2O2 activated metmyoglobin.

Activated metmyoglobin (MetMb) by H2O2 initiates oxidation of microsomal unsaturated fatty acids, beta-carotene and methional but not formate. Lipid peroxidation by activated MetMb was not inhibited by catalase. The activated species which initiates lipid peroxidation appears to be a porphyrin cation radical, PFeIV=O, and not a hydroxyl radical.

Animals↗
PubMed1985

Initiation of membranal lipid peroxidation by activated metmyoglobin and methemoglobin.

The interaction of hydrogen peroxide (H2O2) with metmyoglobin (MetMb) led very rapidly to the generation of an active species which could initiate lipid peroxidation. The activity of this prooxidant decreased rapidly during the first minutes, but 50% of its activity remained stable for more than 30 min. In this model system, it was found that small amounts of H2O2 (1-10 microM) could activate MetMb for significant lipid peroxidation. The incubation of the sarcosomal lipids with activated MetMb caused oxygen absorption. No absorption of oxygen was determined in the presence of membrane with MetMb or H2O2 alone. Methemoglobin (MetHb) was also found to be activated by H2O2 and to initiate lipid peroxidation. Membranal lipid peroxidation initiated by activated MetMb was inhibited by several reducing compounds and antioxidants. However, several hydroxyl radical scavengers and catalase failed to inhibit this reaction.

Animals↗
PubMed1985

Brain: body ratio and conceptional age in vascular-induced intrauterine growth retarded rabbits.

Vascular induced intrauterine growth retardation (IUGR) was achieved by total ligation of approximately 30% of the placental vessels to half the fetuses in the last third of gestation in pregnant rabbits. A correlation between brain weight, body weight and head circumference was established in fetuses and rabbit pups in the perinatal period. The brain:body ratio in restricted IUGR animals was significantly higher than their homologous normal controls. A cephalization index based on the brain:body ratio is proposed to assess adverse effects on brain maturity in the presence of IUGR induced by placental insufficiency.

Animals↗
PubMed1985

The cephalization index: a screening device for brain maturity and vulnerability in normal and intrauterine growth retarded newborns.

Predictive estimates of future neurological maldevelopment as a result of vascular induced intrauterine injury are based on the assumption that the body is more affected than the brain resulting in asymmetrical intrauterine growth retarded (IUGR) newborns. The higher the brain:body ratio, the more severe the IUGR process and the greater the risk for the brain to be affected. This prompted us to study in human newborns, a cephalization index based on the ratio of head circumference to body weight to express the degree of brain maturity and possible vulnerability in relation to gestational age. The newborn cephalization index was correlated with neurodevelopment. A trend could be delineated; in the later gestational age, the higher the cephalization index reflecting a greater degree of brain vulnerability, the more severe the clinical pathology; especially the likelihood of cerebral palsy and severe psychomotor retardation. The cephalization index may serve as an additional screening device for high risk intrauterine growth retarded newborns.

Body Weight↗
PubMed1985

Calcified subdural haematomas associated with arrested hydrocephalus--late sequelae of shunt operation in infancy.

Calcified chronic subdural haematomas (SDH) and features of arrested (compensated) hydrocephalus were demonstrated by skull radiography and cranial computed tomography (CT) in two children who had no neurological deficit. Ventricular surgical drainage had been performed 8 and 11 years prior to admission and the haematomas remained subsequently undetected. The following presentation will serve to illustrate the characteristic radiological features of this entity, the issue of management, and includes a review of the literature.

Adolescent↗
PubMed1985

Vascular-induced intrauterine growth retardation: relations between birth weight and the development of biochemical parameters in young rabbits.

The development of biochemical parameters (cellular DNA and protein) in relation to birth weight was studied in the rabbit, a perinatal brain developer. To induce intrauterine growth retardation and to increase the number of low-birth-weight rabbits, experimental ischemia, in half the fetuses of each doe, was achieved by total ligation of approximately 30% of uteroplacental vessels during the last third of gestation. Following natural delivery, the rabbit pups were raised until 60 days of age, at which time the brains were removed and dissected into cerebral hemispheres, cerebellum and brain stem. The amount of DNA (representing cell number) and protein (suggesting cell size) was estimated in each brain region. A significant correlation was found between low birth weight and reduced DNA in the cerebellum and reduced protein in the cerebral hemispheres. These persistent deficiencies could be related to some lasting handicaps, especially motor incoordination, as an expression of cerebellar dysfunction.

Animals↗
PubMed1983

Delayed visual maturation.

Three infants, recognised as blind during the first 4 months of life, were found to be normal on neurological and ophthalmological examinations. Visual electro-diagnostic studies showed normal retinal responses, but delayed conduction velocities and impaired visually-evoked responses over the occipital cortex. After age 6 months, normal vision developed gradually and all abnormalities disappeared.

Developmental Disabilities↗
PubMed1983

The effect of chronic anticonvulsant therapy on serum lipids and lipoproteins in epileptic children.

We measured serum lipids and lipoproteins in 33 epileptic children who were treated with phenobarbital, valproate, and carbamazepine. High-density lipoprotein cholesterol (HDL-c) was significantly higher in the epileptic children than in two control groups: healthy nonepileptic children, and epileptic children before starting anticonvulsant therapy. Our findings indicate that anticonvulsant drugs should be added to the list of substances that affect serum HDL-c.

Adolescent↗
PubMed1983

Standardization of the Denver developmental screening test for Israeli children.

The Denver Developmental Screening Test (DDST), standardized in the USA, is used for the early detection of developmental disabilities. For use in Israel, the DDST required translation into Hebrew and standardization for Israeli children in view of the test's known cultural bias. The sample included 2,248 children between the ages of 2 wk and 6.5 yr, and was stratified by demographic, ethnic and socioeconomic characteristics to approximate a representative cross-section of the Israeli population. The testers were not psychologists but they received special training. Our results revealed significant differences between the norms of the DDST and its Israeli version, mainly in the personal-social items. For 23 test items there was a difference of greater than 20% between the ages at which they were achieved by 50% of Israeli and Denver children, and for 35 items, there was a difference of greater than 20% in the 90th percentile ages in the two groups. Israeli children showed earlier development in language and personal-social items, while the Denver sample showed earlier development in fine and gross motor skills. The time range between the 25th and 90th percentile in many of the items in the Israeli sample was greater than in the Denver sample. There were sufficient differences between the findings in the two groups to justify using the Israeli version for the local population.

Age Factors↗