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Biomedical subjects

F Ito

Publications and source records attributed to F Ito.

At least 361 records · Page 20Linked to original sources
PubMed1966

Properties of stretch receptors in cat extraocular muscles.

1. The properties of fifty-two stretch receptors in the extraocular muscles were studied in thirty cats. Between ten and twenty-eight receptors were observed in each preparation.2. In four preparations, spontaneously discharging receptors were observed, with afferent fibre conduction velocities ranging from 16.9 to 41.1 m/sec.3. In the remaining twenty-six cats, the minimal threshold receptors ranged from 3 to 130 g, with a peak distribution between 10 and 20 g, and afferent fibre conduction velocities ranging from 6.5 to 52.0 m/sec, the peak being between 10 and 15 m/sec. Of these receptors, nineteen were quickly adapting and seven were slowly adapting.4. The dynamic and static indexes of all the receptors were essentially similar; they both increased markedly on increasing the initial length. This suggests that the receptors do not lie in contact with regions of reduced viscosity on the muscle fibres comparable to the equatorial region of the intrafusal muscle fibres.5. All of the receptors were located in the muscle; none was located in the tendon. Forty-seven of forty-nine receptors were in parallel and two receptors were in series with the contractile elements.6. The properties of all the receptors studied appeared to be similar, suggesting that a single type of stretch receptor is located in the inferior oblique muscle of cats.

Animals↗
PubMedDate not supplied

Selective blockage of the sensory terminal activites by micro-application of tetrodotoxin in the frog muscle spindle.

Micro-application of tetrodotoxin to the sensory nerve terminal of the frog muscle spindle made a semi-blocked condition, in which propagated spikes were blocked selectively but reversibly, while abortive spikes survived. In the semi-blocked condition an antidromic spike was often followed by an abortive spike without a significant pause, in contrast with the normal condition in which the antidromic spike was always followed by an abortive spike or a propagated spike with a pause more than 50-100 msec. An analysis of the spike train as a stochastic point process suggests that the abortive spikes originate at the places which the antidromic spike can scarcely invade in the semi-blocked condition.

Animals↗
PubMedDate not supplied

Miniature end-plate potentials in the frog muscle spindle.

Spontaneous miniature end-plate potentials (m.e.p.p.s) were recorded from the intrafusal muscle fibers in the muscle spindles isolated from the frog sartorius and semitendinosus muscles by means of microelectrode (intracellularly) and across a vaseline gap made transversely on the intrafusal bundle (extracellularly). The latter method was available to record simultaneously the m.e.p.p.s and the afferent terminal activities, of which the latter was easily distinguishable from the former by concomitant occurrence with the axonal responses. Simple type spindles in the sartorius muscle have a restricted end-plate region along the intrafusal bundle on either side of the capsule, while complex type spindles in the semitendinosus muscle are innervated by plural regions which are found on both sides of the capsule in most preparations. Application of 2X hypertonic Ringer's solutions with NaCl or sucrose induced an increase in the rate of the m.e.p.p.s preceding a decrease in the rate of afferent discharges from the spindle.

Afferent Pathways↗
PubMedDate not supplied

Post-infectious leukoencephalopathy as a complication of Mycoplasma pneumoniae infection.

We report a 9-year-old girl with leukoencephalopathy who demonstrated serologic evidence of a Mycoplasma pneumoniae infection. She had a mild upper respiratory tract illness 10 days prior to admission and developed walking difficulty and somnolence. The neurologic symptoms progressed to semicoma and spastic paraplegia over a few days but began to improve on the fourth day. Cranial computed tomography on the eleventh day revealed an area of diffuse low density in the white matter. Cerebrospinal fluid examination was normal. The patient recovered with minimal motor deficits. Cranial computed tomography was normal. She was diagnosed as having leukoencephalopathy complicated by a Mycoplasma pneumoniae infection. The pathogenesis of this infection is believed to be an allergic reaction to Mycoplasma pneumonia of the central nervous system as well as an acute disseminated encephalomyelitis.

Child↗
PubMedDate not supplied

Aicardi syndrome: postmortem findings.

A 2-month-old infant with the typical clinical features of Aicardi syndrome (i.e., infantile spasms, chorioretinal lacunae, and agenesis of the corpus callosum) is reported. At 5 years of age, pathologic examination revealed cortical heterotopias, rostral agenesis of the corpus callosum, hypoplasia of the unilateral optic nerve, and bilateral cerebellar hemispheres. Cavum septum pellucidum was present. A literature review of 5 autopsied patients with this syndrome is included.

Agenesis of Corpus Callosum↗
PubMedDate not supplied

Cerebral metastases of alveolar rhabdomyosarcoma in an infant with multiple skin nodules.

PURPOSE: This report describes extremely rare cases of infantile rhabdomyosarcoma with multiple skin nodules. They are of interest not only for their anatomic sites, but also for subsequent cerebral metastases with sudden cranial hypertension. PATIENTS: Two infants had multiple skin nodules and excisional biopsy revealed alveolar type rhabdomyosarcomas. The patients were treated with tumor resection and combined chemotherapy without any clinical progression for 9 and 16 months, respectively. RESULTS: Evidence of cerebral metastases developed with sudden vomiting and convulsion as the first manifestation. In one patient, urgent radiographic examinations failed to reveal lesions except for dilated cerebral ventricles. Seven weeks after the onset of the neurologic symptoms, only Gd-DPTA-enhanced magnetic resonance imaging (MRI) revealed multiple punctate metastatic lesions hyperintense to the surrounding cerebral tissue. Despite appropriate chemotherapy, both patients had disease progression and died of central nervous system metastases. CONCLUSIONS: The authors emphasize the need to recognize the multiple cutaneous presentation of infantile rhabdomyosarcoma and the association of cerebral metastases as a potential and fatal complication. The diagnosis is facilitated by Gd-DPTA-enhanced MRI, particularly when cerebral computed tomography scans fail to disclose metastatic lesions.

Biopsy↗