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N Tsuru

Publications and source records attributed to N Tsuru.

48 records · Page 3Linked to original sources
PubMed1979

Frontal kindling in rabbits and its influence on visual and auditory evoked response.

Frontal kindling in rabbits, prolongation of the duration of afterdischarge concomitant and clinical manifestations and the epileptic foci (primary and independent secondary foci) were revealed. Auditory and visual evoked responses were recorded after completion of the kindling phenomenon. 1. Electrical stimulations, 300 microA, 60 Hz. 1 msec in duration, 2 sec train, were applied once a day. Clinical manifestations were divided into five stages: 1) the arrest of behavior or no response, 2) the adversive movement with a tonic and/or clonic convulsion of left paw, 3) the adversive movement following mastication, facial spasms and postictal stupor, 4) falling down abruptly and generalized convulsive seizure, and 5) generalized seizure followed by rotatory movement, vocalization and myoclonus. The appearance of five generalized convulsions was defined as a completion of the kindling phenomenon. 2. The duration of afterdischarge increased stepwisely from 2--3 sec to more than 400 sec. However, there was no constant duration of AD even though the animal showed generalized convulsion after completion of the kindling phenomenon. 3. Visual and auditory evoked responses were recorded after completion of kindling. There was a change in the auditory evoked response but not in the visual. A shortening of the latency of P2 component (73.3 msec in peak latency), N2 component (146.7 msec in peak latency) and amplification of the amplitude of N2 component were noticed. Thus, the intermittent weak electrical stimulation on the frontal cortex in rabbits induced generalized convulsion and produced primary and independent secondary epileptic focus on EEG, and the change of auditory evoked response was recognized in kindled animals.

Animals↗
PubMed1976

Kindling in the frog: development of spontaneous epileptiform activity.

The present report is the first demonstration of the kindling phenomenon in a non-mammalian, poikilothermic species. Brief (2 sec) localized electrical stimulation was delivered to the hippocampal cortex of one hemisphere of the partially paralyzed bullfrog, Rana catesbeiana, at current levels just sufficient to elicit brief after-discharge (AD) on first application. Succeeding stimulations, once per hour, gave rise to more and more prolonged AD involving first the side stimulated (1 degree focus) and secondly the opposite hemisphere (2 degree focus). In addition to these stimulus-dependent alterations, after several hours spontaneous, paroxysmal discharges occurred in interstimulus intervals. They appeared first in the stimulated hemisphere, then as evoked spikes in the secondary hemisphere, and finally independently on the two sides. The waveshape of the spontaneous epileptiform potentials exhibited an extraordinary constancy from complex to complex which was specific to each animal. Such wave-shape coherence implies a constancy to both the anatomical substrate and the sequency of synaptic engagement each time spontaneous paroxysmal activity invades the network. The model is especially suitable for analysis of temperature-dependent biochemical events responsible for this functional transformation.

Animals↗
PubMed1975

Secondary epileptogenesis in frog forebrain: effect of inhibition of protein synthesis.

Secondary epileptogenesis was induced in the hippocampal cortex of the paralyzed bullfrog by means of localized, unilateral, intermittent electrical stimulation (kindling). Stimuli were designed to yield a brief but definite after-discharge. In control animals a progressive increase in after-discharge duration occurred at the 1 degree (stimulated) site and then at the 2 degrees site (contralateral hippocampus). Spontaneous epileptiform potentials (SEP's) occurred between stimuli, eventually independently on both sides. Cycloheximide (50 mg/kg) caused 88-99% reduction in protein synthesis, measured by 14C-leucine incorporation into brain protein. Cycloheximide-treated animals revealed no evidence of progressive prolongation of after-discharge duration when subjected to the kindling procedure (p = 0.1205 X 10(-7)). SEP's were reduced in the cycloheximide-treated animals, and confined to 1 degree hemisphere (p = 0.6 X 10(-10)). Since cycloheximide did not disturb normal electrogenesis or disrupt the after-discharges, this experiment distinguishes processes dependent upon electrical events from those requiring macromolecular synthesis. Protein synthesis seems critical to the emergence of spontaneous and autonomous epileptiform behavior of neural aggregates.

Animals↗
PubMedDate not supplied

Neuronal firing pattern following amygdaloid kindling in unrestrained rats.

Chronic recordings of amygdaloid neurons were performed on freely moving rats following kindling. Satisfactory recordings were obtained from 22 amygdaloid neurons of the contralateral amygdala before, during, and after unilateral kindling. Kindling stimulations were given once per hour. Seven cells disappeared during kindling. Seven cells were recorded during the full course of kindling. These units showed (a) an increase in spontaneous firing, (b) a development of high-frequency bursts (the peak interval of the interval histogram decreased from 18 to 2 ms), and (c) high-frequency firings during spontaneous activity that were similar to the firings recording during afterdischarge.

Amygdala↗
PubMedDate not supplied

Effect of unilateral dentate nucleus lesions on amygdaloid kindling in rats.

Amygdala kindling is used to investigate cerebellar dentate nucleus participation in the neuronal plasticity of the cerebrum. We studied the behavioral change, the occurrence of epileptiform events, and the duration of afterdischarge during amygdaloid kindling under control conditions and after a dentate lesion of the contralateral cerebellum. Our results indicate that the dentate lesion induced the facilitation of the behavioral development of the amygdaloid kindling, whereas there was only a slight increase in the duration of afterdischarge and the spontaneous epileptiform potential of the amygdala. There was a discrepancy between the behavioral kindling and the electroencephalographic epileptic activity. Therefore the dentate lesion must play a role in controlling the generalization mechanism of epilepsy. We also found that on a right amygdala that had been influenced by a left dentate lesion there were few spikes, while on the left amygdala there were frequent spikes. These results suggest that the dentate nucleus plays an important role in amygdaloid kindling as well as in the neuronal plasticity of the amygdala.

Amygdala↗
PubMedDate not supplied

Nephropathy of nail-patella syndrome.

Ultrastructural renal lesions of a sporadic case of nail-patella syndrome are described. Although the patient, an 8-year-old Japanese boy, had no clinical renal syndrome, electron microscopy disclosed the presence of collagen fibrils and electron lucent areas within glomerular basement membrane. Comparative observation of glomeruli in sections stained by uranyl-acetate and lead-citrate and those by PTAH-uranyl revealed evidence of many collagen fibrils in mesangial matrix, as well as glomerular basement membrane. At the follow-up study 3 years after the biopsy, he still showed normal urinalysis and no renal dysfunction. Characteristic ultrastructure of glomerulus of this disease can be present even in cases without any apparent clinical renal involvement. It is concluded that the glomerular lesions in nail-patella syndrome may be caused by abnormal metabolic processes of collagen in glomeruli rather than entrapment of circulating collagen precursors.

Basement Membrane↗
PubMedDate not supplied

Recognition and management of aluminum intoxication in children.

The awareness of aluminum as a potential toxic risk in patients, especially infants and children with chronic renal insufficiency, is beginning to be widely appreciated. This paper will review the clinical features of aluminum intoxication, potential sources of aluminum, risk factors in pediatrics, and treatment of aluminum intoxication. It is hoped that this review provides the nephrologist with useful information concerning recognition and management of aluminum intoxication.

Aluminum↗
PubMedDate not supplied

Chronic renal failure in children.

It is important to appreciate that the recent advances in nutritional management over the past two decades (19-22) have added to the longevity and the "joie de vivre" of children with chronic renal failure. The significant advances in vitamin D therapy and new treatment of complications in long-term maintenance dialysis have provided the pediatric nephrologist with new avenues of management.

Adolescent↗