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Biomedical subjects

Y Haeuchi

Publications and source records attributed to Y Haeuchi.

6 recordsLinked to original sources
PubMed1999

Immunohistochemical demonstration of neuropeptides in the articular disk of the human temporomandibular joint.

The distribution of calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY) was examined in the human temporomandibular articular disk using an indirect immunofluorescent method. All examined neuropeptides were observed in nerve fibers in the disk. These fibers were mostly located in the loose fibrous tissue of the posterior part (posterior attachment) and in the lateral region of the anterior part (anterolateral loose fibrous tissue) of the disk. The posterior attachment and anterolateral loose fibrous tissue occasionally contained isolated nerve fibers which usually showed immunoreactivity (IR) for CGRP or SP. In this tissue, perivascular fibers contained VIP or NPY, whereas isolated fibers and free nerve endings showed the IR for CGRP or SP. These neuropeptides may be involved in the regulation of blood flow and/or pain sensation in the human articular disk of the temporomandibular joint.

Aged↗
PubMed1989

[Self-setting apatite cement. VII. Barium-apatite as radio-opaque medium].

Addition of barium hydroxyapatite (BaAp) successfully bestowed clinically acceptable radioopacity to the self-setting apatite cement consisting of an equimolar mixture of tetracalcium phosphate and dicalcium phosphate dihydrate. To accelerate the setting reaction which was retarded by Ba2+ released from BaAp at a lower pH during first stage of spatulation with 20 mM phosphoric acid, calcium hydroxyapatite (CaAp) was added to the cement mixture. At about 20 wt% of BaAp and 20 wt% CaAp, the setting reaction proceeded at a neutral or weak alkaline pH, which is one of the most promising aspects of the self-setting cement and assures that this type of cement may be the least irritating of the dental cements presently available. The cement spatulated at L/P = 0.4 set within 10 minutes and its radiopacity was comparable to or more than that of tooth enamel. The wet compressive strength of the set cement stored for one day in synthetic saliva at 37 degrees C was approximately 100 kgf/cm2. Although this value is almost one fourth that of 40 wt% CaAp cement, this cement appears to be strong enough to apply as root canal filling material.

Barium↗
PubMed1988

Effect of the porosity of the filler aggregates on the setting expansion of investment material.

Twenty experimental phosphate-bonded investments were prepared by the mixing of two types of fillers (spherical glass beads and irregularly shaped silica particles) with five types of filler aggregates of different porosities, and two different ratios of MgO to NH4H2PO4. These investments were mixed with three different liquids, and their setting expansion, time until setting expansion began (induction time), and fluidity were measured under constant experimental conditions. The following results were obtained: (1) The setting expansion was significantly related to bulk porosity of filler aggregates, not to packed porosity, despite variations in type of filler, ratio of MgO to NH4H2PO4 or type of liquid; and (2) the fluidity and the time until setting expansion began were also related to the bulk porosity of the filler aggregates.

Chemical Phenomena↗