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Biomedical subjects

K Hosaka

Publications and source records attributed to K Hosaka.

At least 91 records · Page 5Linked to original sources
PubMed1989

Endogenous digoxin-like activity of mammalian-lignans and their derivatives.

A comparative study was made on the endogenous digoxin-like activity of sixteen mammalian-type lignan derivatives including enterolactone and enterodiol. Cross-reactivity to antidigoxin antibody, inhibition of dog kidney Na+,K+-ATPase, and ouabain displacing activity against [3H]ouabain binding to human erythrocytes on the part of these derivatives were examined and compared in all cases with that of ouabain. meso-2,3-Dibenzylbutane-1,4-diol (meso-HA-1) was found to possess the most potent cross-reactivity to antidigoxin antibody. Several lignans, particularly HA-1 (either meso or dl), dl-2,3-bis(3-methoxybenzyl)butane-1,4-diol(HA-4), dl-2,3-bis(3,4-dimethoxybenzyl)butane-1,4-diol(HA-10), dl-2,3-bis(3,4-dimethoxybenzyl)-1,4-dimethoxybutane(HA-11), and trans-2,3-bis(3,4-dimethoxybenzyl)-gamma-butyrolactone(HA-14) were capable of inhibiting Na+,K+-ATPase activity with IC50 at a concentration less than 5 x 10(-4) M. Meso-HA-1, HA-11 and HA-14 also showed [3H]ouabain displacement activity with IC50 at a concentration of 10(-4)-10(-3) M. These determinations of activity were made at doses 100-1000 times those of ouabain. The synthetic lignans are considered to derive in vivo from plant material usually present in fibrous food. Based on the data obtained, some lignans may possibly be endogenous digitalis-like substances.

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↗
PubMed1987

Isolation and characterization of a yeast mutant defective in cholinephosphotransferase.

A yeast mutant defective in cholinephosphotransferase (cpt) was isolated as a revertant from a choline-sensitive mutant, which exhibited lowered phosphatidylinositol synthesis. A block at the cholinephosphotransferase step in the mutant was indicated by the enzyme defect and the accumulation of CDP-choline in the cells with a decrease in phosphatidylcholine synthesis. The defect was due to a single recessive mutation in a nuclear gene. The residual activity in the mutant showed an increased apparent Km for CDP-choline and an altered sensitivity to Tween 20. Thus the structural gene may be affected in the mutant. The occurrence of an intact ethanolaminephosphotransferase in the mutant indicates the distinctness of the genes encoding cholinephosphotransferase and ethanolaminephosphotransferase in yeast. The present selection method was also effective for isolating mutants defective in the other steps of the CDP-choline pathway and choline transport.

Choline↗
PubMed1985

A colorimetric method for the determination of hydroxamic acid by iodine oxidation.

A new colorimetric method for the determination of hydroxamic acid is described. Hydroxamic acid was oxidized quantitatively by iodine to produce nitrous acid, which was thereafter determined according to the diazocoupling reaction. This method is sensitive to as little as 5 nmol of hydroxamic acid, and the calibration curve is linear up to 50 nmol. Using this method, acyl-CoAs were determined after conversion to hydroxamic acid by the addition of hydroxylamine. The present method is applicable to the determination of free fatty acids which are activated by acyl-CoA synthetase.

Chemical Phenomena↗
PubMed1985

Incompetent urethral sphincter in a girl with a unilateral single ectopic ureter.

A rare case of an incompetent urethral sphincter associated with a unilateral single ectopic ureter is reported. Urinary incontinence persisted even after removal of a dysplastic kidney draining into the vagina. No neurological defect was found. Manual compression of the bladder elicited urine leakage from the urethra, and the urethral closure pressure was markedly low. Cystometry and voiding cystourethrography were normal. Continence was restored completely by a urethral sling operation.

Child↗
PubMed1985

Ileal conduit diversion from a bivalved kidney.

We report 2 successful cases of ileal conduit diversion from a bivalved kidney. Both patients had a single kidney and were in chronic renal failure. Cutaneous diversion had malfunctioned because of intrarenal obstruction of tuberculous origin. The kidney was bivalved and anastomosed to an isolated ileal segment. The lower end of the ileal segment was brought to the abdominal skin as a stoma. Postoperatively, renal function was aggravated temporarily. During the followup periods of 2 years and 1 year 6 months neither patient had evidence of renal deterioration. This type of urinary diversion seems acceptable for relieving infundibular stricture with chronic renal failure.

Adult↗
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↗