Search PubMed⌕ Search

Biomedical subjects

K Arita

Publications and source records attributed to K Arita.

At least 181 records · Page 10Linked to original sources
PubMed1989

[Studies on factors causing tooth resorption. 2. Dose-response effects of indomethacin on resorption of deciduous teeth in rabbits].

The aim of the present study was to confirm whether prostaglandin (PGs) had any connection with physiological root resorption. 16 young rabbits aged 7 days which had been in utero for 32 days were used and were divided into 4 groups. The control group was injected with normal saline solution, and the experimental groups were injected with indomethacin, a specific inhibitor of PGs synthetase, in doses of 0.1 mg/kg, 1.0 mg/kg, 10.0 mg/kg every 12 hours for 5 days, respectively. All animals were sacricfied at 11 days postnatal. Their maxillary deciduous incisors were embedded in paraffin and sectioned serially in 7 mus thickness. The number of odontoclasts appearing on the root surface were counted, and the volume of the maxillary deciduous incisor was measured. The results were as follows: 1. The readings of the odontoclasts appearing in the control group was 260.3 +/- 60.1, and those of the experimental groups injected with 0.1 mg/kg, 1.0 mg/kg, 10.0 mg/kg indomethacin were 249.0 +/- 32.2, 199.5 +/- 15.1 (P less than 0.05 one sided test) and 163.8 +/- 40.0 (P less than 0.01), respectively. The number of odontoclasts was reduced linearly as the logarithmic dose of indomethacin increased. 2. As far as the volumes of the maxillary deciduous incisors were concerned, that of the group with 10.0 mg/kg was significantly greater than that of the group with 0.1 mg/kg (P less than 0.05). In comparison with the control and the experimental group, the volume of the 10.0 mg/kg group was greater than the others, but statistical differences were not found.

Animals↗
PubMed1989

[Histological study on root resorption of upper permanent incisor].

In the permanent tooth, physiological root resorption does not occur, but inflammatory resorption occurs due to the orthodontic force, ectopic eruption of neighboring tooth and others. In this study, the morphological and histological investigation of the root resorption of the upper permanent incisors caused by the ectopic eruption of the canine was carried out. The left central incisor and lateral incisor from a 12-year-old female were examined. The roots were resorbed almost completely, and in part the resorption extended into the enamel. The results were as follows: 1. In the resorbed dentine, two types of resorption lacuna were observed. One was in direct contact with resorption tissue and the other was repaired with cementum-like tissue. 2. In the resorption lacuna, no odontoclast was recognized. 3. The pulp tissue was normal and the internal resorption was not seen. 4. On the wall of the root canal connected with root resorption, a large amount of hard tissue was formed, and on the external surface of the root, secondary cementum was formed on the primary cementum. 5. Under the scanning electron microscope, the clear dentine tubules in the resorption lacuna, the shallow, unclear resorption lacuna with deposition of the hard tissue and the various steps between them were observed.

Child↗
PubMed1989

[Severe root resorption of maxillary incisors and ectopic eruption of maxillary canine].

A 12-year-old female with severe root resorption in the maxillary left central and lateral incisors (Case 1) and a 27-years-old female with the maxillary left canine erupted in the position of the central incisor (Case 2) were examined and treated. The findings and treatment procedures were as follows: 1. In Case 1, severe root resorption was caused by the ectopic eruption of the canine. On the lingual surface, the resorption had proceeded to a part of enamel. 2. In the Case 1, after the central and lateral incisors were extracted, the canine was carefully guided into the position of the lateral incisor. 3. In Case 2, treatment was not performed, because the chief compliant was carious lesions and the patient did not mind the malposition of the canine. 4. In both Case 1 and 2, the main reason of ectopic eruption of canines was presumably not a discrepancy between the tooth material and the basal arch length but the malposition of the tooth germ and/or abnormal eruption process of the canine.

Adolescent↗
PubMed1989

[Effects of mastication and submandibular gland ectomy on the growth ability of isoproterenol-stimulated parotid gland and other tissues in male mice].

In a previous article we reported that mastication played an important role in the development of submandibular glands in male mice. Submandibular glands contain epidermal growth factor (EGF) which stimulates the proliferation of various cells in developing animals. In this study, the effects of the hypotrophy of submandibular glands caused by reduction of mastication and the removal of the glands on the growth ability of isoproterenol (IPR)-stimulated parotid glands and other tissues were investigated. The animals in the experiment were male mice and they divided into three groups, a control group fed a solid diet, a group fed a paste diet and a group with removed submandibular glands fed a solid diet. In comparison with the group fed a solid diet, in the group fed a paste diet a small decrease was found, and in the group with the ectomized submandibular gland a significant decrease in the rise of ornithine decarboxylase (ODC) activity, S-adenosylmethionine decarboxylase (SAMDC) activity and DNA synthesis of parotid glands caused by IPR stimulation were found. The DNA synthesis of the heart tissue of mice with ectomized submandibular glands was lower than that of the control group, but in liver, lung, stomach and testis tissue no decrease of DNA synthesis was found. These results suggest that mastication and the submandibular glands have an effect of the growth of the tissues in male mice.

Animals↗
PubMed1989

[Dentigerous cysts of children treated by cyst wall enucleation. Report of eleven cases].

The present paper describes ten children with eleven cases of dentigerous cysts which were treated by extraction of the primary teeth, cyst wall enucleation and lingual-arch spacemaintainer. The patients were seven boys and three girls, with a mean age of nine years two months, in Hellman's Dental Age IIIA and IIIB. In eight of the cases, the mandibular second premolar was involved, and of the remainder, two cases involved the first premolar, and one case, a maxillary lateral incisor. In eight out of the eleven cases, the pulp of the primary tooth had been treated. Radiographically, nine cases exhibited a pericoronal space of 15 mm-35 mm and two cases 50 mm-55 mm. The material for histological examination, typically, gave the appearance of a stratified squamous epithelium showing chronic inflammation. Healing took place more rapidly than routine marsupialization. In eight cases the successor erupted in the normal position without orthodontic treatment, in two cases with light orthodontic power. In one case the behavior of the permanent tooth was kept under observation. From the above, this approach to treatment by cyst wall enucleation and lingual-arch spacemaintainer would appear to be very useful for the young child.

Child↗
PubMed1989

[Effect of epidermal growth factor (EGF) on proliferation of the cells derived from the root resorbing tissue of human deciduous teeth].

The resorption of the roots of deciduous teeth is a physiological phenomenon. Many morphological and histological investigations of the root resorption have been reported. However little biochemical data concerning systemic factors in it are available. In this study, cell culture derived from the root resorbing tissue of human deciduous teeth was tried and the effect of EGF on that cell was examined. The dissected root resorbing tissue from human deciduous teeth was cultured in a medium containing 10% fetal calf serum in a humidified incubator at an atmosphere of 5% CO2 in air at 37 degrees C. The outgrowing cells from root resorbing tissue were a mixed population of mesenchymal cells and epithelial cells during the early stage of cultivation, but at the later stage they changed to morphologically single population. The mesenchymal cells seemed to be derived from the dental sac and the epithelial cells from the enamel organ or the oral mucoepithelium. These cells seemed to be useful for analysis of the systemic factors in the root resorption. The effect of EGF on the proliferation of cells obtained as stated above was examined. EGF markedly stimulated DNA synthesis about by a factor of 6.9 for the mesenchymal cells and by a factor of 3.4 for the epithelial cells. These results suggested that EGF participates in the root resorption of human deciduous teeth.

Epidermal Growth Factor↗
PubMed1989

[A case of jugular foramen meningioma in a child].

The common tumors originating in the jugular foramen are chemodectoma and schwannoma. Jugular foramen meningioma is extremely rare. Review of the literature revealed only seven reported cases of this tumor. The authors present a child case of jugular foramen meningioma with intra and extracranial extension. A 9-year-old boy was admitted to the Department of Neurosurgery, Hiroshima University School of Medicine on March 20, 1985. Since the age of 3, the patient had hoarseness and was found to tilt his neck when he shouted. Since the age of 6, he was found to nod when he swallowed. At the age of 8, he developed swallowing difficulties. On admission, his general condition was unremarkable except for his lean build (126 cm in height and 23 kg in weight). An elastic hard and immobile mass was palpable in the left upper neck deep in the atrophic sternocleidomastoid muscle. Neurological examination revealed involvement of the ninth, tenth, eleventh, and twelfth cranial nerves. A plain skull roentgenogram and laminogram revealed hyperostosis around the left jugular foramen, and narrowing of the canal. CT with contrast enhancement revealed a high density mass in the left cerebellopontine angle extending through the jugular foramen to the left parapharyngeal space. Cerebral angiography did not show any abnormal findings except for complete blockage of the left sigmoid sinus. On April 4, 1985, subtotal removal of the intracranial tumor was performed using suboccipital craniotomy. Then, on July 3, 1985, the left parapharyngeal tumor was excised through a cervicofacial incision. Finally the residual tumor in the jugular foramen was excised using suboccipital approach on August 18, 1986.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Neoplasms↗
PubMed1988

A case of large prolactinoma supposed to be cured by bromocriptine therapy.

The authors reported a patient with a large prolactinoma (PRL 1,716 ng/ml) who was treated with bromocriptine for two years and followed up for a subsequent 36 months. After the start of the therapy, the tumor size was dramatically reduced, and finally the disappearance of the tumor was confirmed by high resolution coronal CT. The serum prolactin level and pituitary function were normalized. The tumor has not regrown and the blood prolactin level has remained normal for 36 months since the discontinuation of bromocriptine administration. This is a very rare case report on the eradicative effect of bromocriptine on such a large prolactinoma. Another characteristic of this case was that the prolactin reserve was maintained not only before the therapy but also during the early stage of the therapy.

Adult↗
PubMed1988

[Hypothalamic pituitary function in brain death patients--from blood pituitary hormones and hypothalamic hormones].

According to the report of the Health and Welfare Ministry's research committee on brain death (1985), "brain death is defined as an irreversible cessation of the total brain function including brain stem." However, in brain death patients, whether the hypothalamic function which belongs to the brain stem function has completely ceased or not is unknown. In order to evaluate the hypothalamic function in brain death patients, the blood levels of the pituitary hormones and hypothalamic hormones were measured, and anterior pituitary stimulation test with triple bolus injection (TRH 500 micrograms, LH-RH 100 micrograms, regular insulin 0.3-0.7 unit/kg) was performed. The subjects were 13 brain death patients whose clinical states fully satisfied the criteria proposed by the committee. 1) The average blood levels of anterior pituitary hormones in these brain death patients were within normal range, and that of growth hormone was more than the twice of the normal level. 2) The blood anterior pituitary hormones were detectable in almost all cases even several days after the diagnosis of the brain death. 3) LH reserve was maintained in three cases. FSH reserve was maintained in three cases. Prolactin reserve was maintained in two cases. TSH reserve was maintained in one case. 4) Blood ADH (antidiuretic hormones) were detectable in 7 cases out of 9 cases. The blood ADH level of one case, in particular, was rather high (above 10 pg/ml). 5) Histopathologically anterior pituitaries were examined in three autopsy cases. The central necrotic areas were observed in all cases, but normal pituitary tissues existed peripherally. And all anterior pituitary hormones could be recognized immunohistochemically. 6) The blood levels of the hypothalamic hormones (GRF, CRF, LH-RH) were measured in four cases. The hypothalamic hormones were detectable in all cases. In one case, the levels of GRF were within normal range even 9 or 15 days after the diagnosis of brain death.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Ossified prolactinoma: case report.

The authors report a case of ossified prolactinoma that was identified as a calcified nodule on the roentgenograms. Histologically, the ossified tissues were diffuse, and the osteoid was mineralized in various degrees, subsequently forming bones. Adenoma cells were sparse among the ossified tissues. This is probably the first report of ossified pituitary adenoma associated with osteoid metaplasia. The pathogenesis of osteoid metaplasia in pituitary adenomas is possibly due to proliferative connective tissue resulting from degeneration of the pituitary adenoma; this connective tissue may possess osteogenic potency.

Adult↗