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Biomedical subjects

A Gutman

Publications and source records attributed to A Gutman.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Ring 18 chromosome with mental retardation, hemidysmorphism, and mitochondrial encephalomyopathy.

A 2 1/2-year-old female is reported with ring 18 chromosome syndrome. The chromosomal abnormality was found in all examined leukocytes and cultured skin fibroblasts. Besides the usual clinical characteristics of this syndrome, two additional features are described that have not been reported previously: right hemidysmorphism, including hypertrophy of the tongue and lower extremity; coloboma of the lower right side of the gums; atretic external right ear canal; and hypotonia with mitochondrial encephalomyopathy associated with excessive ketonemia during normal food intake and a large increase after overnight fast.

Brain Diseases↗
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Infantile idiopathic myopathic carnitine deficiency: treatment with L-carnitine.

A series of 9 infants, ranging in age from 3 months to 5 years (average: 2 years), suffered from idiopathic myopathic carnitine deficiency presenting as hypotonia and motor delay. Secondary carnitine deficiency was eliminated by appropriate tests. Muscle carnitine concentration ranged from 2.3-7.1 nmol/mg non-collagen protein (NCP; average: 4.87 nmol/mg NCP; normal: 22 +/- 6 nmol/mg NCP). Lipid accumulation in muscle was observed in 2 of 8 patients. Therapy with L-carnitine (100 mg/kg/day in most patients) was given with clinical and laboratory follow-up 6 months later. In 7 of 9 patients, muscle tone and motor function improved. Muscle carnitine concentration increased to a range of 2.7-23.4 nmol/mg (average: 12.27 nmol/mg). In some patients the muscle carnitine content multiplied by a factor of 3-4, but carnitine concentration reached the normal range in only 2 patients. Most infants with idiopathic carnitine deficiency did benefit from 6 months of therapy; however, in order to achieve full recovery the duration of therapy should probably continue for longer periods, with a dose of not less than 100 mg/kg/day.

Adolescent↗
PubMedDate not supplied

Total parenteral nutrition with intralipid in premature infants receiving TPN with heparin: effect on plasma lipolytic enzymes, lipids, and glucose.

Plasma lipolytic activity (lipoprotein lipase and hepatic lipase), free fatty acids (FFA), triglycerides, cholesterol, and glucose levels were measured in 21 premature infants [gestational age 26-37 weeks (mean +/- SEM 30.4 +/- 0.63 weeks), aged 1-8 days (mean +/- SEM 3.00 +/- 0.35 days)]. All infants were maintained on total parenteral nutrition with heparin (1 U/ml) and were given Intralipid, 1, 2, and 3 g/kg/day, over 15 h on days 1, 2, and 3, respectively. Blood samples were drawn before and at the end of Intralipid administration. Baseline plasma lipolytic activity, before the start of lipid infusion, was 1.54 +/- 0.24 U/ml (1 U = 1 mumol [3H]oleic acid released from tri[3H]olein/h). Lipolytic activity increased after lipid infusion to 4.04 +/- 0.96, 4.32 +/- 0.63, and 6.09 +/- 1.00 U/ml on days 1, 2, and 3 of the study. Hepatic lipase amounted to 38-47% of total lipolytic activity. During the 3 days of lipid infusion, there were dose-dependent increases in plasma FFA, triglyceride, and cholesterol. Whereas FFA and triglyceride concentrations returned to prelipid infusion levels 9 h after stopping the infusion of Intralipid, 1, 2, or 3 g/kg, there was a cumulative increase in plasma cholesterol and glucose concentrations. The close correlation between FFA concentrations and plasma lipolytic activity (r = 0.655, p less than 0.001) suggests considerable intravascular lipolysis. The positive correlation between plasma FFA and triglycerides (r = 0.632, p less than 0.001) and FFA and cholesterol (r = 0.582, p less than 0.001) indicate, however, that intravascular lipolysis does not prevent the lipemia associated with Intralipid infusion to low birth weight infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
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Phenotype and genotype variation in primary carnitine deficiency.

PURPOSE: Primary carnitine deficiency is an autosomal recessive disorder of fatty acid oxidation resulting from defective carnitine transport. This disease is caused by mutations in the carnitine transporter gene SLC22A5. The objective of this study was to extend mutational analysis to four additional families with this disorder and determine whether recurrent mutations could be found. METHODS: The SLC22A5 gene encoding the OCTN2 carnitine transporter was sequenced, and the missense mutations identified were expressed in Chinese hamster ovary (CHO) cells. RESULTS: DNA sequencing revealed four novel mutations (Y4X; dup 254-264, 133X; R19P; R399Q). Alleles introducing premature STOP codons reduced the levels of OCTN2 mRNA. Carnitine transport in CHO cells expressing the R19P and R399Q mutations was reduced to < 5% of normal. The 133X mutation was found in two unrelated European families. Two patients within the same family, both homozygous for the same mutation (R399Q) had completely different clinical presentation. CONCLUSIONS: Heterogeneous mutations in the SLC22A5 gene cause primary carnitine deficiency. Different presentations are observed even in children with identical mutations.

Animals↗
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[Theory of the EEG potential in models of the leptomeninges of the brain. IV. Radial dipoles and their double layers in the depths and on the surface of the brain].

The estimaiton of ECoG-potentials is fulfilled by means of a simple model of the isolated sphere, which is exact enough, as it was proved earlier [1]. A simple limit formula for the qualitative estimation of ECoG-potentials of a source situated in the cerebral cortex is obtained. The EEG as in [2] is obtained using the transformation of the first 20 spheric harmonics. The experimental facts of registration of the evoked potentials of comparatively little subcortical sources were explained theoretically. Numerical results of the model are used to estimate the intensity of the field induced in the brain by two electrodes placed on the scalp.

Brain↗
PubMedDate not supplied

[Adiabatic solution of the Ohmic cable equation. General theory, homogeneous cylindrical fiber].

An adiabatic solution of the Ohmic cable equation is suggested, which reduces the non-stationary equation to a stationary form. The adiabatic length constant of the stationary equation is time-dependent. The adiabatic solutions for the boundary conditions that change in time linearly and exponentially were studied. In the latter case, the adiabatic length constant does not depend on time though it differs from the usual length constant. The cable input characteristics of exact and adiabatic solutions were compared in the cases of the voltage- and current-clamp, and electric field stimulation. The adiabatic and exact solutions are identical for the rising exponential stimuli. For the falling exponential stimuli, the adiabatic solution determines the exact asymptotic solution if the stimulus decays slower than the relaxation of initial conditions. It is propose to use linear and exponential ramp stimulation in electrotonic measurements.

Models, Theoretical↗
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[Adiabatic solution for the Ohmic cable equation. An homogeneous cell, prospects for electronic measurements].

Exact and adiabatic electrotonic solutions [1] were calculated for reconstructed motoneurone and hippocampal interneurone in case of linear and exponential ramp stimulation by the fixed current, potential or homogenous electric field. For the rising exponential ramp the solutions are identical. In case of the decaying exponent the adiabatic solution becomes an asymptote for the exact one if the stimulus decays slower than relaxation of the initial conditions in the cell. If the stimulus decays faster, the asymptote is the current or potential axis, depending on the stimulation mode. For electrotonically short cell, the exact solution approaches the asymptote faster. The solution for the exponentially rising field does not depend on the dendritic tree configuration and depends only on the effective electrotonic length of the neurone. It could be useful to apply ramp stimulation, especially exponential ramp of the electric field, to estimate electrotonic parameters of cells.

Electricity↗
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[The branching structure of the bistable dendrite].

A branching structure consisting of three bistable cylindrical branches was considered. Both stable and unstable solutions for the voltage distribution in such a structure, were obtained using the method developed in our laboratory. This made it possible to calculate the input current-voltage characteristic of the bistable branching structure, including unstable segments of this characteristic. Possible stable states of the structure when its proximal end is loaded by a resistance were determined. It is shown that the binary exclusive-OR could be accomplished by the elementary branching structure of a bistable dendrite. A model with overexcitation carried out by Ca-dependent K channels was developed. It is shown that the model parameters do not fall outside the physiological range of values.

Calcium Channels↗
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[Criteria of bistability of the cylindrical dendrite with the variable negative slope of the N-shaped current-voltage membrane characteristic].

The criteria for hystheresis in the input current-voltage relation of a cylindrical dendrite, i.e. cable bistability, were studied earlier in case of the constant negative slope of the N-shaped membrane current-voltage characteristic. For a membrane with a variable negative slope of the current-voltage characteristic, only sufficient conditions of dendritic bistability were formulated: [equation: see text], where df/dV/h is the negative slope of the membrane current-voltage characteristic at zero current point, h; X is the electrotonic length of the dendrite. We propose to use as the necessary condition of bistability the above equation but with the maximal value of the negative slope df/dV/max instead of df/dV/h. Calculations illustrate that this necessary condition, with acceptable accuracy, can be used as the necessary and sufficient condition of the cable bistability when the N-shaped current-voltage characteristic of the membrane is arbitrary.

Algorithms↗
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[EEG potential theory in a model with thin brain integuments. I. Multilayer spherical cable model].

The problem of finding EEG potentials is solved assuming that integuments of the brain are regarded as infinitely thin spheres. The potential is not changed along the radius in the layers with high conductivity, and the current in the resistive layers is only radial. It is shown that the EEG potentials could be described exactly enough supposing the lower bone plate to be an ideal isolator. The potentials of EEG are obtainable from ECoG by means of a comparatively simple algebraic procedure.

Electroencephalography↗
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[Relation between the excitatory synaptic currents and clamped somatic potential in the model of neuron with nonlinear dendrites].

The influence of the clamped somatic potential on the excitatory synaptic current (EPSC) was studied in the model of the dendrite with N-shaped instantaneous stationary current--voltage curve. Proximal EPSC diminish and become narrower with decreasing hyperpolarization or modest depolarization, distal EPSC increase and become wider, intermediately distant EPSC change insignificantly. Under increasing depolarization all the EPSC become significantly wider and larger. EPSC facilitate stable depolarization of the dendrites. When the dendrite is stable depolarized EPSC becomes very small and narrow, but it becomes larger and wider as the soma is hyperpolarized. EPSC becomes especially large and wide when the soma is hyperpolarized just to terminate the stable depolarization of the dendrite branch where the active synapses are located. The model explains certain phenomena which are difficult to understand by the theory of ohmic dendrites. New phenomena are predicted.

Dendrites↗
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[The theory of current fields induced by scalp electrodes].

In order to solve the problem of electrostimulation with the help of scalp electrodes the simplified general theory was developed. The analysis was carried out in a framework of multilayer sphere-cable. The formuli of potential on the surface of scalp and in the volume of brains were worked out. The theory was concretized for traditional bipolar and new differential ways of fixing of the stimulating electrodes. The goal is to use the obtained theory for numerical estimation of electrical parameters of brain envelopments and for calculation of the values of electrical field in the volume of brains.

Brain↗
PubMedDate not supplied

[Shape and amplitude of stimulating postsynaptic potentials in a neuronal model with an N-shaped volt-ampere characteristic of the dendritic membrane].

We developed a model of a neuron with N-shaped current--voltage characteristic of dendritic membrane and studied the change of shape and amplitude of excitatory postsynaptic potentials (EPSP) when changing the place of synapses on dendrites. Local EPSP can activate slow inward current. Consequently, the EPSP amplitude does not always diminish when the rise- and decay-time increases. In some cases the rise- and decay-time of a more distant synapse may become shorter than that of the more approximate one. The common method of judging about the location of synapses by means of the shape of EPSPs may be wrong.

Cell Membrane↗
PubMedDate not supplied

Glycogen storage disease type II in Israel.

Eighteen patients with alpha-glucosidase deficiency have been diagnosed in Israel during the last 15 years. All patients were Palestinian Arabs, with the exception of two siblings from a Jewish Iraqi family. Clinically all patients had the infantile type (Pompe's disease), except one who had the juvenile type. Muscle glycogen content varied from 4 to 17% wet weight. Muscle alpha-glucosidase activity was zero in 10 of 17 patients examined. Among the seven patients in whom residual activity was present, the highest value was 18% of normal. Leukocyte alpha-glucosidase activity was highly variable, making this tissue unfit for enzymatic diagnosis of the disease. A marked heterogeneity was found in pH profiles of muscle and leukocyte alpha-glucosidase activity. A high prevalence of the disease in the Arab population was noted. In spite of a high rate of consanguinity, only a small number of autosomal recessively inherited diseases have been shown to be unusually prevalent in the Arab population. In view of the serious prognosis of this disease, prenatal diagnosis should be offered to affected families.

Ethnicity↗