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Biomedical subjects

K Nagae

Publications and source records attributed to K Nagae.

At least 19 recordsLinked to original sources
PubMed2001

[Pulmonary hypertension associated with refractory hyperthyroidism: a case report].

A 25-year-old woman was admitted to our hospital with goiter. The diagnosis was Grave's disease. Diagnostic transthoracic echocardiography revealed a hyperdynamic stage of the heart with right ventricular dilation. Doppler echocardiography showed mild to moderate tricuspid regurgitation and elevated systolic right ventricular pressure. Right heart catheterization revealed high cardiac output (9.49 l/min) and pulmonary hypertension (57 mmHg) with increased pulmonary vascular resistance and total pulmonary resistance. No intracardiac shunts were detected. Since neither thiomazole nor propylthiouracil was effective and both caused side effects, she underwent subtotal thyroidectomy. After the surgery, pulmonary hypertension improved and cardiac output normalized, but without normalization of pulmonary vascular resistance and total pulmonary resistance. Reversible pulmonary hypertension may occur in patients with hyperthyroidism. Increased pulmonary blood flow and sustained high pulmonary artery resistance were suspected as the causes of pulmonary hypertension. In addition, pulmonary endothelial dysfunction as a result of sustained increased pulmonary blood flow could be another cause of pulmonary hypertension.

Adult↗
PubMed1994

Change in blood levels of vitamin B-6 derivatives in pregnant and lactating rats.

By using an HPLC method which we have developed, concentration changes of vitamin B-6 derivatives in blood of pregnant and lactating rats were studied. PLP and PL were the main derivatives in plasma and erythrocytes, and occasionally, PMP was found in the plasma of rats fed a normal solid diet which contained 8.3 mg PN.HCl/kg diet. Upon pregnancy, the plasma PLP concentration decreased significantly (p < 0.01), whereas plasma PL tended to increase (p < 0.05). PLP concentration in erythrocytes tended to increase upon pregnancy. These results suggest that metabolism or utilization of vitamin B-6 is altered upon pregnancy and that plasma PLP concentrations alone may not be a good indicator of nutritional status. Further confirmation was needed for so from erythrocyte samples under our analytical conditions was not so from erythrocyte samples under our analytical conditions was not converted to PIC-P via PLP, after the sample was treated with glyoxylic acid and then with KCN.

Animals↗
PubMed1991

Effect of the infraorbital nerve transection on the sensory input subsystem in the masticatory system of newborn mice.

To confirm a hypothetical idea that the masticatory system will play a fundamental function in the postnatal growth of the body, the centripetal mastication-related information flowing in the system was interrupted by cutting the infraorbital nerve on the newborn mice. The sham- and axotomy-operation mice were returned to their mother. 20 days after the operation the sensory input unit was studied in the serial frontal section histologically. On the other hand the body weight was measured every 5 days after the operation and the significant level was examined statistically. The results obtained are as follows: 1) The sensory input units (primary and secondary sensory neurons) have completely reduced to disappear in situ. 2) The significant differences between both groups were seen at the level of P less than 0.001 from the period of 20-day after the operation. In comparison with that of the sham-operation mice, the axotomy-operation mice have decreased about 20 to 30% in the body weight and so reduced in shape, characterized by the smaller head, a shorter trunk and limbs and a shorter, thinner tail. The experimental data suggest that the centripetal mastication-related information plays an important role in the postnatal growth of the masticatory system and the other functional systems of the body.

Animals↗
PubMed1989

Histological properties and biological significance of pouch in red kangaroo, Macropus rufus.

2 embryos, 4 youngs, 4 older youngs and the pouch of 2 mothers of the red kangaroos were examined. The results obtained are as follows: 1. The initial muscle spindles are already observed light microscopically in the vertebral, dorsal neck and forelimb muscles of the newborn baby and a little bit later in the masticatory muscles of the young of 68 mm in craniorump length and 28 g in body weight. 2. In the skin with less hair lining the inner surface of the pouch, abundant apocrine large sweat glands are observed, especially surrounding the basal region of the nipple and in the pleat formation of the skin. 3. The lactiferous mammary gland is enlarged, the lobules being divided by the interlobular muscle fiber tissue and enwrapped by the muscular capsule. The milk is squirted automatically by the muscle fiber contraction from the gland to the nipple, to which the baby attaches itself. 4. The musculature of the pouch wall is developed to form the sphincter muscle in the pouch orifice. The sphincter muscle plays an important role in conditioning the optimum temperature for the naked baby inside the pouch. 5. The apocrine perfume plays an important role in guiding the baby on the journey to the pouch after birth and the apocrine products also in maintaining the optimum humidity of the pouch to accomodate the baby. 6. During the long period of stay in the pouch, the masticatory and locomotive systems and their neuromuscular mechanism related to the herbivorous mastication become fully established and then the young leaves the pouch to feed on the animal's proper diet.

Abdominal Muscles↗
PubMed1988

Morphological studies of the neuromuscular mechanism shifting from sucking to biting of mice.

In order to give a neuroanatomical evidence to the mechanism of shifting from sucking to biting, we investigated in prenatal, newborn and postnatal mice whether there is a time difference in the neurogenesis of the neurons relative to sucking and biting or in the histogenesis of their peripheral effector organs by the HRP labeling technique and electron microscopy. The results obtained are as follows. (1) At birth the facial motoneurons exceed the trigeminal motoneurons in cell area and development. (2) After birth, the trigeminal motoneurons grow rapidly and outstrip the growth of the facial motoneurons at the age of 6 days. (3) Thereafter, the cell area of both neuron types continues to increase gradually. (4) The initial sign of the alpha motor end plates is found in the orbicularis oris muscle innervated by the facial nerve in 17-day-old fetuses, while that of the trigeminal nerve is delayed in the masseter muscle of 18-day-old fetuses. (5) The initial sign of the muscle spindle appears with the sensory terminals in the masseter muscle of 17-day-old fetuses and the fundamental structure of the muscle spindle is formed in 4-day-old youngs. (6) Myelination of the facial nerve begins in 3-day-old youngs, while that of the trigeminal nerve becomes apparent in 4- or 5-day-old youngs. From these bases, it is obvious that the facial nerve elements related to sucking are firstly developed at birth and that the differentiation of the trigeminal nerve elements related to biting is rapidly accelerated after birth.

Animals↗
PubMed1988

Origin of lingual proprioceptive afferents in Japanese monkey, M. fuscata fuscata. Studied by HRP-labeling technique.

The peripheral course of the axon of the lingual proprioceptive neurons in 5 Japanese monkeys was studied by injecting HRP into the distal part of the hypoglossal nerve through the proximal stump. The present authors confirmed that the HRP-labeled cell bodies appeared ipsilaterally in the C2, C3 and C4 spinal ganglia. The afferents to the C2, C3 and C4 ganglia pass through the ansa hypoglossi and direct neuronal anastomosis existing between the first cervical nerve and the hypoglossal nerve. It was confirmed that in the Japanese monkey, having abundant muscle spindles in the tongue, the lingual proprioceptive neuron soma exist in the C2, C3 and C4 spinal ganglia, their peripheral axons passing through the ansa hypoglossi and the direct neuronal anastomosis.

Animals↗
PubMed1988

Degeneration of the primary snout sensory afferents in the cervical spinal cords following the infraorbital nerve transection in some mammals.

To obtain the neuroanatomical information on the role of the snout sensory input in mastication, the present study was conducted on young and adult mice, young Wistar rats and adult Japanese shrew-moles. The animals were subjected to unilateral and bilateral infraorbital nerve transection. Transganglionic degeneration was studied by the Nauta method and electron microscopy including HRP application to the neck muscles. Transganglionic degeneration was found in every experimental case. 1. Transganglionic degeneration of the fibers was found not only in the main sensory nucleus and spinal tract nucleus of the trigeminal nerve but throughout the cervical and the upper part of the thoracic spinal cord. 2. These transganglionically degenerated fibers descended bilaterally through the cuneate nucleus and then caudally through the posterior funiculus at the obex level. They then entered the dorsal and ventral horns to make a synaptic contact with the degenerated synapses on the dorsal horn cells and with the multipolar cells in the ventral horns. This neuroanatomical information suggests: 1) that the trigemino-neck muscle reflex will be generated monosynaptically by the primary neurons arising from the snout sensory organs and 2) that these primary neurons may play a large role as a neuronal bridge in connecting the masticatory reflex system and the cranio-neck reflex system.

Animals↗
PubMed1988

Degenerative changes of the primary trigeminal axons and neurons following infraorbital nerve transection.

The sensory input of the Vth cranial nerve might play a great role in the feeding activity of the mammals, especially of the Japanese shrew-moles. After the transection of the pure sensory infraorbital nerve, a drastic structural disorder was observed in the rat masseter muscle. In order to give anatomical evidence as to whether the interference of the sensory input affects the peripheral effector, electron microscopic investigations were performed on the primary axons and neurons of the Japanese shrew-moles. The results obtained are as follows: The preganglionic part of the transected nerves showed drastic degenerative changes of the myelinated fibers, characterized by a prominent decrease in the large- and medium-sized myelinated axon fibers, a gradual numerical increase of the clustered or isolated unmyelinated axons, and the frequent appearance of macrophages. The ganglion cells exhibited displacement of the nucleus with infolding of the nuclear membrane, the appearance of a large amount of lipofuscin granules, and an increase of neurofilaments and reduced Nissl bodies. The transganglionic part of the sensory root exhibited mainly a predominant axonal destruction, accompanied by myelinated disintegration.

Animals↗
PubMed1988

Localization of proprioceptive neurons innervating the muscle spindles of pig extraocular muscles studied by horseradish peroxidase labelling.

Each muscle of the extraocular muscles, containing abundant muscle spindles, was exposed to horseradish peroxidase (HRP) on 8 young pigs (2-month-old, 20-30 kg in body weight, both sexes). The results obtained are follows: The HRP-labelled neurons innervating the superior rectus muscle were always found in a crescent ventro-medio-dorsal fashion in the most medial position of the contralateral oculomotor nucleus. The HRP-labelled cells for the medial rectus muscle appeared close to the superior rectus group in the ipsilateral nucleus. The labelled cells for the inferior rectus muscle appeared in the ventrolateral position of the ipsilateral nucleus and those for the inferior oblique muscle in the area between the medial rectus and inferior rectus muscle groups. The labelled cells for the superior oblique muscle were found in the contralateral trochlear nucleus and those for the lateral rectus muscle bilaterally in the abducens nuclei, predominantly on the ipsilateral side and poorly on the contralateral side. The HRP-labelled cells were composed of large (alpha) and small (gamma) multipolar cells and of bipolar, oval or round (proprioceptive) cells, all intermingled together within the nucleus. The bipolar cells have been also identified in the 3 nuclei by means of Nissl staining technique. On this basis, they should be considered as the proprioceptive neurons. In the shrew-moles, the cell bodies of the proprioceptive neurons innervating the snout muscle spindles have been found close to the ipsilateral glossopharyngeal ganglion and those of the somatic sensory neurons in the ipsilateral trigeminal ganglion. In the pigs, no HRP-labelled cells were found in the trigeminal mesencephalic tract nucleus, but the HRP-labelled cells were found in the ipsilateral trigeminal and the superior cervical sympathetic ganglia. From the results, it could be emphasized that the proprioceptive neurons innervating the pig extraocular muscle spindles are located within the nuclei of the IIIrd, IVth and VIth cranial nerves.

Animals↗
PubMed1988

Degenerative changes of primary neurons following tooth extraction.

In summarizing the present experimental results of tooth extraction, it can be emphasized that the disturbance of the sensory input units from the teeth resulted in a definite degeneration of the primary neurons. On this ground, it is suggested that the lesion of the sensory input units in the masticatory computer system, according to the individual age affected, may become a large factor in impeding the masticatory activity and accelerating the aging of the masticatory function.

Animals↗
PubMed1988

Central projection of proprioceptive afferents arising from maxillo-facial regions in some animals studied by HRP-labeling technique.

20 ICR mice (adult females) were used for analyzing the axonal projection of the trigeminal mesencephalic tract neurons and 10 Japanese shrew-moles for analyzing that of the snout proprioceptive neurons. The HRP-labeled axons were found to be ipsilaterally terminated in the trigeminal motor nucleus, supratrigeminal nucleus and trigeminal main and spinal tract nuclei, lateral pontine-medullary reticular formation, vagal dorsal motor and hypoglossal nuclei and the lamina V of the C2 spinal cord segments. No HRP-labeled axons were found in the facial and solitary nuclei and the cerebellum. Also, the functional localization of the trigeminal mesencephalic tract neurons was analyzed with the retrograde tracers of fluorescent compounds injected into the jaw-closing muscles having spindles. The fluorescent-labeled neurons were found to be intermingled throughout the nucleus and clustered at the caudal level of the nucleus. Also, double or triple fluorescent-labeled neurons were not observed in the nucleus. The HRP-labeled axon bundle of the facial proprioceptive neurons are divided rostro-caudally into the shorter ascending and the longer descending roots, both running closely dorsal to the trigeminal spinal tract nucleus. The ascending root lies adjacently dorsal to the spinal tract nucleus, giving off the terminal fibers to it, to the wider area of the dorso-medial pontine nuclei and finally to the cerebellar nuclei. At the level of the facial inner genu, it turns medially to meet the facial nerve root, giving off the terminal fibers to the facial motor nucleus and to the raphe nuclei and to the opposite nuclei bilaterally. The HRP-labeled descending root takes the course caudally at least down to the C3 segment of the spinal cord, giving off the terminal fibers to the spinal tract nucleus, the nuclei of the IXth, Xth and XIIth cranial nerves and the pontine-medullary reticular formation. In the spinal cord, it descends bilaterally through the posterior fascicles, giving off the terminal fibers to the dorsal and ventral horns.

Afferent Pathways↗
PubMed1985

Ultrastructural changes of neuromuscular receptor organs in the masseter muscles following unilateral transection of the rat infraorbital nerve.

Definite ultrastructural changes of the neuromuscular receptor organs were demonstrated in the young and adult rat masseter muscles either on the operated or unoperated side following the unilateral transection of the infraorbital nerve. The grade of the degeneration was intensive but quite similar in having no relation to the age of the rat when the operation was performed, while it increased drastically with time after the operation. On this base, it may be suggested that the sensory input coming from the various kinds of sensory receptors in the snout field do rather affect bilaterally the minor reflexive movements of the jaw. In other words, it can be said that the minor reflexive movements of the jaw might have been controlled by the sensory inputs coming from the snout sensory receptor organs. The definitely degenerated changes of the neuromuscular receptor organs in the masseter muscles should be regarded as disuse atrophy following the interception of the snout sensory input.

Animals↗
PubMed1985

Experimental morphological studies on the functional role of the pulpal nerves in dentinogenesis.

The role of the pulpal nerves in the dentinogenesis of the rat dentition was studied experimentally by means of a time marker of lead acetate and by electron microscope after the individual dissection of the trigeminal and cervical sympathetic nerves or both. Following trigeminectomy, the longitudinal growth of the denervated incisor decreased. Contrary to this, following cervical sympathectomy, the longitudinal growth of the denervated incisor and molar increased 10-5%, and the collagen fibers increased predominantly in the pulpal tissue. The sympathetic nerves seem to play an important part in controlling the differentiation of the odontoblasts, inhibiting the maturation of the growth center of the apical pulp in the continuously developing teeth.

Animals↗
PubMed1985

Structural and functional adaptation of the pulpal nerve fibers in the rat incisor.

Special fine structure of the pulpal nerve fibers adapted to the continuously growing incisor was studied on 20 rats (25-d-old-males) electron microscopically and was compared with that of the molars of limited growth. The incisal pulp was innervated by 2 kinds of the nerve fibers derived from the cervical sympathetic and the trigeminal ganglia: polyaxonal unmyelinated and monoaxonal myelinated. In the apical pulp, however, the pulpal nerve fibers were unmyelinated, showing 3 different profiles in the fine structure: 1. polyaxonal, 2. polyaxonal with dial plate-like profile and 3. monoaxonal. The monoaxonal unmyelinated fiber reflected the transverse profile of the unmyelinated part of the myelinated axon derived from the trigeminal ganglion. It can be concluded that the pulpal nerve fibers derived from the trigeminal ganglion maintain the immatured nature in the apical proliferating pulp to adapt to the continuous growth of the incisor.

Animals↗
PubMed1984

Mirror movement: application of movement-related cortical potentials.

In a patient with Kallmann's syndrome (hypogonadotropic hypogonadism and anosmia) manifesting mirror movement, cortical potentials associated with unilateral and bilateral simultaneous voluntary middle finger extensions were studied. Premovement negative slope, which has been shown to reflect preparatory excitation of motor cortex corresponding to the voluntary movement, was recorded bilaterally in this patient in spite of intended unilateral hand movement. It is suggested that mirror movement in this particular patient is generated by unintended excitation of the opposite motor cortex.

Adult↗