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  • 1
    Electronic Resource
    Electronic Resource
    Chronological and immunohistochemical observations of cerebellar dysplasia and vermis defect in the hereditary cerebellar vermis defect (CVD) rat (1997)
    Springer
    Acta neuropathologica 94 (1997), S. 549-556 
    Details
    ISSN: 1432-0533
    Keywords: Key words Bergmann glia ; Cerebellar dysplasia ; Immunohistochemistry ; Mutant rat ; Walker’s lissencephaly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Hereditary cerebellar vermis defect (CVD) rats, a new neurological mutant, developed both cerebellar vermis defect and cerebellar dysplasia. Developmental alterations in the cerebellum of the CVD rats were studied chronologically and immunohistochemically. The earliest architectural abnormality was a maldevelopment of the inferior cerebellar peduncle from embryonic day 17 (E17), leading to an indistinct separation between the cerebellum and the pons. From E19, the CVD rats lacked vermis development and, therefore, the cerebellar hemispheres were fused. After birth, Purkinje cells and external granule cells (EGCs) penetrated into the pontine tissue, but retained their normal position until postnatal day 10. Cerebellar lamination began to be disturbed due to abnormal perivascular aggregations of the EGCs, resulting in convoluted and occasionally perivascular lamination. There were no Bergmann glia in the heterotopic cerebellum of the pons, and abnormally arranged Bergmann glia were observed in the mildly disorganized cerebellar hemispheres. Immunohistochemistry for calbindin revealed that abnormal orientation of the Purkinje cells might be related to the perivascular EGCs. Parvalbumin-immunopositive microneurons were seen only in the disarranged molecular layers, and synaptophysin-immunopositive cerebellar glomeruli were present in the afflicted internal granular layers. These findings suggest that perivascular EGCs may play an important role in cerebellar dysplasia and the developmental plasticity in the altered cerebellogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050749
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  • 2
    Electronic Resource
    Electronic Resource
    Activity of primate putamen neurons is selective to the mode of voluntary movement: visually guided, self-initiated or memory-guided (1992)
    Springer
    Experimental brain research 89 (1992), S. 473-477 
    Details
    ISSN: 1432-1106
    Keywords: Voluntary movement ; Putamen ; Context dependency ; Single-unit recording ; Trigger stimulus ; Monkey ; Basal ganglia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this report was to investigate the neural processes of movement initiation and control in which the basal ganglia play an essential role. Single-neuron activity was recorded in the putamen of monkeys performing learned arm movements initiated in three different modes: sensorially guided, internally-timed self-initiated and memory guided. There were no significant differences in the magnitude and timing of both prime mover and supporting muscle activity between the three modes of movement. Over half of the task-related neurons showed strong activity in one of the three modes of movement initiation, but were only slightly activated in the other two modes. No clear preference for a particular movement mode was evident in the population of putamen neurons as a whole. These results are consistent with the hypothesis that there are heterogeneous groups of neurons in the putamen, and that each group of neurons participates in retrieving a different kind of information required for movement based on either external sensory events or on internally stored information.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229870
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  • 3
    Electronic Resource
    Electronic Resource
    Cell wall-associated peroxidase in cultured cells of liverwort, Marchantia polymorpha L. Changes of peroxidase level and its localization in the cell wall (1985)
    Springer
    Plant cell reports 4 (1985), S. 54-57 
    Details
    ISSN: 1432-203X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Most of the peroxidase activities from cultured cells of Marchantia polymorpha L. were found in the cell wall. The activities increased markedly after the beginning of stationary growth. Cytochemical examination using an electron microscope indicated that the peroxidase was localized in the layers of the cell wall. The increase of peroxidase released from the cells into the culture medium was closely correlated with the increase of the peroxidase level in the cell wall. The release of peroxidase seemed to be caused by fragmentation of the cell wall stripped from cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269205
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  • 4
    Electronic Resource
    Electronic Resource
    Role of Gestational Age and Body Weight on Doppler Transmitral Flow Velocity Pattern in Very Low Birth Weight Infants (1996)
    Springer
    Pediatric cardiology 17 (1996), S. 242-245 
    Details
    ISSN: 1432-1971
    Keywords: Key words: Doppler echocardiography — Transmitral flow — Very low birth weight infant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Doppler transmitral flow velocity was measured in premature infants. The early diastolic peak velocity, the peak velocity of early diastole/peak velocity of atrial contraction ratio, and total flow velocity–time integral increased significantly with advancing gestational age and body weight. The peak filling rate normalized to stroke volume (NPFR) did not correlate with gestational age or body weight. Moreover, mean NPFR was not significantly different between premature and term infants. Thus NPFR demonstrates that changes in the left ventricular filling patterns with advancing gestational age and increasing body size are related to the progressive increase in loading conditions, rather than to sequential changes in myocardial properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002469900053
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  • 5
    Electronic Resource
    Electronic Resource
    Postnatal Changes in Left Ventricular Volume and Contractility in Healthy Term Infants (1997)
    Springer
    Pediatric cardiology 18 (1997), S. 91 -95 
    Details
    ISSN: 1432-1971
    Keywords: Key words: Ductus arteriosus — Left ventricular volume — Contractility — Neonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. To evaluate how the size of the ductus arteriosus affects neonatal left ventricular (LV) volume and contractility, we serially obtained two-dimensional and Doppler echocardiograms at 2, 12, 24, and 120 hours after birth in 20 healthy infants. LV volume was calculated by the biplanar Simpson's rule, and ductus arteriosus size with left-to-right shunting was measured by two-dimensional and Doppler echocardiography. At 2 hours, the ductus arteriosus was at its maximal size, and the LV end-diastolic volume was 1.2-fold higher than at the subsequent hours after birth. Additionally, there was a significant linear correlation between the end-diastolic volume and the ductal diameter. In contrast, the peripheral vascular resistance, derived from blood pressure measurements and Doppler echocardiography, was lowest at 2 hours of age. The mean normalized systolic ejection rate, an index of contractility, remained constant throughout the study period. These results suggest that alterations in the LV end-diastolic volume soon after birth depend on changes in ductal flow, which in turn is affected by ductal diameter, and that the neonatal left ventricle operates at its maximal performance with limited contractility during ductal patency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002469900123
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  • 6
    Electronic Resource
    Electronic Resource
    Postnatal Left Ventricular Contractility in Very Low Birth Weight Infants (1997)
    Springer
    Pediatric cardiology 18 (1997), S. 112 -117 
    Details
    ISSN: 1432-1971
    Keywords: Key words: Left ventricle — Contractility — Very low birth weight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The objective of the study was to evaluate postnatal changes in left ventricular (LV) contractility in very low birth weight (VLBW) infants. An echocardiographic study comparing 18 VLBW infants without significant complications and 16 normal term infants was carried out at the Neonatal Intensive Care Unit in Akita University Medical Hospital, Japan. The echocardiographic examinations were performed within 6 hours of birth and on day 5. We obtained the relations between rate-corrected mean velocity of circumferential fiber shortening (mVcfc) and end-systolic wall stress (ESS), which were calculated from two-dimensional LV short-axis views to compensate for the distorted LV shape, and we compared these relations statistically. In both VLBW and term infants there were inverse linear correlations between mVcfc and ESS for each study period (p 〈 0.05). The regression line of VLBW infants had a lower y-intercept and a steeper slope than that of term infants at 6 hours of age but almost corresponded on day 5. It is concluded that the left ventricle of VLBW infants adapts to postnatal hemodynamic alterations with low contractility but operates with a contractile state similar to that of term infants on day 5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002469900127
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  • 7
    Electronic Resource
    Electronic Resource
    Serial Pulsed Doppler Assessment of Pulmonary Artery Pressure in Very Low Birth-Weight Infants (2000)
    Springer
    Pediatric cardiology 21 (2000), S. 452-457 
    Details
    ISSN: 1432-1971
    Keywords: Key words: Very low birth-weight infant — Echocardiography — AT:RVET(c) — Pulmonary artery pressure — Chronic lung disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. We assessed pulmonary artery pressure (PAP) during the early neonatal period in very low birth-weight (VLBW) infants using serial echocardiographic measurements of the ratio of the pulmonary artery acceleration time to the right ventricular ejection time corrected by heart rate [AT:RVET(c)]. Eighty-four VLBW infants weighing less than 1500 g were examined using serial color Doppler echocardiography from 3 hours to day 7 after birth. The AT:RVET(c) of infants born after 30 weeks of gestation showed a rapid, significant increase during the early neonatal period, whereas those of the groups born at less than 30 weeks showed no significant increase before day 14. At 24 hours after birth, the AT:RVET(c) values of VLBW infants did not correlate well with either the ratio of the right preejection period to the right ventricular ejection time on M-mode echocardiography or the pressure gradient between the right ventricle and the right atrium, as estimated by tricuspid regurgitation on pulsed Doppler echocardiography. The AT:RVET(c) value for the chronic lung disease (CLD) group did not differ significantly from that for the oxygen-dependent group at any assessment point. During the early neonatal period, the AT:RVET(c) of VLBW infants, as calculated by pulsed Doppler echocardiography, differed with their gestational age and did not appear to correlate well with PAP. Our data also suggest that AT:RVET(c) values may not be a good predictor of the subsequent occurrence of CLD in VLBW infants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002460010107
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  • 8
    Electronic Resource
    Electronic Resource
    Synchronization of motor units and its simulation in parallel feedback system (1976)
    Springer
    Biological cybernetics 21 (1976), S. 107-111 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Comparison of the discharge patterns of soleus motor units with associated changes in force exerted by foot during quiet stance have already demonstrated the following facts. In the initial stage of standing, the motor units exhibited stationary and asynchronous discharges. The force showed a sporadic presence of the high frequency oscillation in the 8–10 Hz band. After five to ten minutes of standing, the firing rate of individual motor unit discharges increased to about 10 spikes/sec and discharges of each motor unit were synchronized and phase-locked to each of the accompanying force oscillation. During this transitional stage, the discharges of motor units were characterized by spike dropouts from an otherwise regular spike train. To simulate the changes in the discharge characteristics, we have proposed a parallel feedback model of the stretch reflex arc. This was made of multiple α-motoneurons, motor units and muscle spindles. And motor units interact each other through group Ia afferent signals. As a result of simulation, motor units were found to exhibit stationary and asynchronous discharges when feedback gain was kept small. With an increase of feedback gain, the firing rate of individual motor units increased and finally the discharges of them were synchronized. During this transitional stage, the spike dropouts were observed in accordance with the experimental results. The neuronal mechanism of synchronization may partly be explained by the interactions of motor neurons through the above stated parallel feedback system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01259393
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  • 9
    Electronic Resource
    Electronic Resource
    Voltage-gated Na+ current availability after step- and spike-shaped conditioning depolarizations of retinal ganglion cells (1998)
    Springer
    Pflügers Archiv 436 (1998), S. 497-508 
    Details
    ISSN: 1432-2013
    Keywords: Key words Excitability ; Partial inactivation ; Persistent Na+ current ; Retinal ganglion cell ; Sub-threshold current
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We used two conditioning voltage protocols to assess inactivation of voltage-gated Na+ current in retinal ganglion cells. The first protocol tested the possibility, raised by published activation and steady-state inactivation curves, that Na+ ions carry a ”window” current in these cells. The second protocol was used, because these cells spike repetitively in situ, to measure the Na+ current available for activation following spikes. Na+ current activated at test potentials more positive than –65 mV. At test potentials more positive than –55 mV, Na+ current peaked and then declined along a time course that could be fit by the sum of a large, rapidly decaying component, a small, slowly decaying component and a non-decaying component. Both step- and spike-shaped conditioning depolarizations reduced the amount of current available for subsequent activation, sparing the non-decaying ”persistent” component. Most of the Na+ current recovered from this inactivation along a rapid exponential time course (τ=3 ms). The remaining recovery was complete within at least 4 s (at –70 mV). Our use of step depolarizations has identified a current component not anticipated from previous measurements of steady-state inactivation in retinal ganglion cells. Our use of spike-shaped depolarizations shows that Na+ current density at 1 ms after a single spike is roughly 25% of that activated by the conditioning spike, and that recovery from inactivation is 50–90% complete within 10 ms thereafter. Na+ current amplitude declines during spikes repeated at relatively low frequencies, consistent with a slow component of full recovery from inactivation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004240050664
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  • 10
    Electronic Resource
    Electronic Resource
    3-Methylglutaconic aciduria type I: Clinical heterogeneity as a neurometabolic disease (1999)
    Springer
    Journal of inherited metabolic disease 22 (1999), S. 1-8 
    Details
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract 3-Methylglutaconic (3-MGC) aciduria with 3-methylglutaconyl-CoA hydratase deficiency (3-MGC aciduria type I) is a rare inherited metabolic disease of L-leucine catabolism. We describe a 9-month-old Japanese boy with this disorder who showed progressive neurological impairments presented as quadriplegia, athetoid movements and severe psychomotor retardation from 4 months of age. This finding indicates the existence of clinical heterogeneity in 3-MGC aciduria type I, suggesting it may present as a neurometabolic disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005421111554
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