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Biomedical subjects

K Hirakawa

Publications and source records attributed to K Hirakawa.

At least 19 recordsLinked to original sources
PubMed1992

The effect of endolymphatic sac obliteration on vestibular sensory hair bundles. A high-resolution scanning electron microscopic investigation.

A tannic acid-osmium staining technique and high-resolution scanning electron microscopy were used to demonstrate changes in the glycocalyx and ciliary interconnections of the vestibular sensory cells of guinea pigs after extradural obliteration of the endolymphatic sac and duct. Three months after the obliteration, it was possible to observe degeneration in the glycocalyx and the ciliary interconnections as well as the tip links. These findings suggest that the endolymphatic hydrops causes an endolymphatic ionic imbalance which affects the glycocalyx and ciliary interconnections resulting in further morphological changes of the cilia. The tip links, which are believed to be involved in sensory cell transduction, also seem to be affected.

Animals↗
PubMed1992

Peritumoral cerebral edema in meningiomas: the role of the tumor-brain interface.

We investigated the role of the tumor-brain interface in the production of peritumoral cerebral edema in meningiomas by analysing the size, shape, histological type and location of the tumor, and radiological and operative findings. Our results suggest that changes of the boundary zone between the tumor and the brain such as the disappearance of the subarachnoid space, cortical thinning or loss, and possibly partial loss of the arachnoid membrane are the most important factors in edema production, and that multiple other factors determine the morphological changes which occur at the tumor-brain interface.

Adult↗
PubMed1992

The role of endothelin-1 in the origin of cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage.

Plasma and cerebrospinal fluid (CSF) endothelin (ET)-1-like immunoactivity in 27 patients with aneurysmal subarachnoid hemorrhage (SAH) was measured serially by radioimmunoassay for 2 weeks after SAH onset. Mean ET-1-like immunoactivity levels in plasma of patients with SAH were highly elevated during the whole study period, while the levels in CSF of the same patients were not. Plasma ET-1-like immunoactivity levels in patients with SAH classified as Fisher computerized tomography (CT) Group 3 were higher than those in patients with SAH classified as Fisher CT Groups 1 and 2. There were no significant differences in plasma ET-1-like immunoactivity levels between the patient groups stratified by Hunt and Kosnik grade. In this series, plasma ET-1-like immunoactivity levels in the 12 patients with vasospasm were higher than those in the 15 patients without vasospasm during the 1st week; CSF ET-1-like immunoactivity levels in patients with vasospasm were in the normal range on Days 0 to 3 after SAH onset, then became elevated on Days 5 to 7 and remained high until the end of the 2nd week. In contrast, CSF ET-1-like immunoactivity levels in patients without vasospasm were within the normal range during the entire period of study. The time course of the occurrence of vasospasm and that of the increase in CSF ET-1-like immunoactivity coincided precisely. The possible role of endogenous ET-1 in the pathogenesis of vasospasm due to SAH is discussed.

Adult↗
PubMed1992

[A clinical observation of cases which was suspected of congenital cholesteatoma].

Four cases which was suspected of congenital cholesteatoma were treated in the past 15 years. The age of the patients ranged from 4 to 17 years. In all cases, the cholesteatoma arose in the middle ear. In one case the cholesteatoma extended into the mastoid cavity. Tympanoplasty of colummella type III was indicated. Postoperative hearing gain was from 20 to 30dB. Although the incidence is low, otolaryngologists must be aware of congenital cholesteatoma when treating conductive hearing loss with a normal ear drum.

Adolescent↗
PubMed1991

Breath hydrogen test using water-diluted lactulose in patients with gastrointestinal amyloidosis.

To investigate small bowel motility in gastrointestinal amyloidosis, lactulose breath hydrogen tests were performed on 16 patients with histologically proven amyloidosis and 12 age- and sex-matched controls. Fasting breath hydrogen concentration (FBHC) was not significantly different between the two groups, but there was a tendency for FBHC in symptomatic amyloidosis patients (median 31.5, range 3-78 ppm) to be higher than in asymptomatic amyloidosis patients (4, 0-34 ppm, 0.05 less than P less than 0.1) and controls (6, 1-19 ppm, 0.05 less than P less than 0.1). Orocecal transit time (OCTT) was significantly delayed in the amyloidosis group (median 150, range 40-220 min) when compared to the controls (60, 20-110 min, P less than 0.01), but OCTT was not statistically different between symptomatic and asymptomatic amyloidosis patients. These data suggest an impaired motility of the stomach and small intestine in gastrointestinal amyloidosis and the possible role of small intestinal dysfunction such as bacterial overgrowth and malabsorption in the occurrence of symptoms in this disorder.

Adult↗
PubMed1991

Cochlear fistula found in a naturally healed tympanic cavity.

A cochlear fistula found in a naturally healed mastoid cavity is reported. The patient is a 53-year-old Japanese woman who was complaining of unsteadiness. She had a long history of otorrhoea in childhood. Her tympanic and mastoid cavities were widely open and were covered by thin epithelium. The posterior wall of the ear canal was missing. She had no hearing in the ear but responded to electrical promontory testing. Exploratory surgery was indicated at which fistulae of the basal turn of the cochlea and the horizontal semicircular canal were found. These fistulae were sealed by pieces of bone and muscle.

Cochlea↗
PubMed1991

Prolongation of renal allograft survival in the rat treated with amniotic fluid.

To assess the role of amniotic fluid (AMF) in the maintenance of pregnancy, immunosuppressive effects of AMF were studied in vivo, and the mechanisms of suppressor activity were analyzed immunologically in vitro in the rat. Female Lewis (LEW, RT-1l) rats mated with Brown-Norway (BN, RT-1n) rats for 14 days were sacrificed and cell-free AMF was obtained. AMF was diafiltered with PBS (PH 7.2) and reconstituted to 2 OD units measured at 280 nm. Untreated LEW hosts rejected BN renal grafts at 7.8 +/- 0.2 days (n = 10). Five days of intravenous inoculation of AMF into LEW hosts remarkably enhanced BN graft survivals (MST = 20.3 +/- 4.4 days, n = 12) compared with controls (P less than 0.01), and slightly prolonged third-party DA (RT-1a) graft survivals (MST = 9.4 +/- 0.8 days, n = 7) compared with control LEW hosts engrafted with a DA kidney (MST = 7.6 +/- 0.2 days, n = 6). Five days of intravenous inoculation of pregnant sera into LEW hosts had no effect on BN graft survival. The AMF suppressed the proliferative response of LEW lymphocytes against not only irradiated BN stimulator cells but also irradiated third-party DA stimulators. The AMF also suppressed allokiller T cell generation of normal LEW lymphocytes against BN cells by 70.1% and 51.3%, and against DA cells by 64.9% and 38.9% at concentrations of 25% and 12.5%, respectively (P less than 0.01). To dissect the immunosuppressive activity of AMF, the effect of AMF on cytokine production and interleukin 2 (IL-2) receptor expression of concanavalin A-stimulated lymphocytes were investigated. AMF suppressed interferon and IL-2 production. Interestingly, however, AMF did not suppress interleukin 3 (IL-3) and interleukin 6 (IL-6) production, as well as IL-2 receptor expression. These results demonstrated that rat AMF displayed a strong immunosuppression in vivo as well as in vitro, and that AMF might play an important role in the maintenance of pregnancy.

Amniotic Fluid↗
PubMed1991

Acquired C1 inhibitor deficiency associated with systemic lupus erythematosus affecting the central nervous system.

A 22 year old woman with systemic lupus erythematosus affecting the central nervous system had acquired C1 inhibitor deficiency. She was admitted for treatment of psychotic behaviour, but showed no signs of angioedema. The serum complement profile of the patient showed normal C3 concentration and a depletion of C4, C2, C1 inhibitor, and C1q. Her parents had normal complement profiles. An extremely reduced C4 concentration may lead to involvement of the central nervous system in systemic lupus erythematosus.

Adult↗
PubMed1991

Functional and morphological changes of the exocrine pancreas in ciclosporin-treated rats.

We have examined whether or not ciclosporin A (CsA) affects structure and function of the exocrine pancreas. Male Wistar rats were treated once a day for 7 days with intraperitoneal injections of vehicle or 5, 15, 30, or 50 mg/kg of CsA. Following the CsA treatment, incorporations of [3H]thymidine into DNA and [3H]orotic acid into RNA were found to be significantly reduced in a dose-dependent manner up to 30 and 15 mg/kg, respectively, at which doses the incorporations reached a plateau. The incorporation of [3H]-L-leucine into protein also decreased by 36% at the dose of 5 and by 53% at the dose of 50 mg/kg of CsA. The activities of amylase and lipase in the pancreas also decreased in the CsA-treated rats. Furthermore, a significant reduction in the specific binding of [3H]N-methylscopolamine to muscarinic receptor was observed following the administration of CsA. The Scatchard analysis for the [3H]N-methylscopolamine binding to the pancreatic membrane revealed a significant decrease in Bmax, but not in Kd values in the CsA-treated animals. In addition, it was found histologically that administration of CsA induced cellular atrophy, cytoplasmic vacuolization, and cellular necrosis in the exocrine pancreas. These results strongly suggest that prolonged treatment with CsA may induce the suppression of pancreatic exocrine functions by decreasing the contents of amylase and lipase as well as the number of muscarinic receptors, possibly by the inhibition of the syntheses of protein and DNA in the exocrine pancreas.

Amylases↗
PubMed1991

[Distribution of glycoconjugates in gerbil hippocampal neurons--histochemical study with lectins].

Paraffin-embedded sections of gerbil hippocampus were made and stained by use of lectins with different sugar specificities: Concanavalin A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin (RCA), Phaseolus vulgaris agglutinin (PHA-E), peanut agglutinin (PNA), soybean agglutinin (SBA), and Vicia villosa agglutinin (VVA) to investigate the distribution of glycoconjugates in this brain region. Nuclear membranes of all the neurons in the hippocampus were positively stained with Con A and PHA-E, whereas WGA revealed definite staining of cell membranes. Endothelial cells of blood vessels were intensely positive to RCA, suggesting its usefulness as a marker of endothelial cells. With SBA and VVA, a few neurons in Ammon's horn were positively stained, while no positive cells were observed in the dentate gyrus. CA2 and the medial part of the CA1 were also positive bilaterally with SBA and VVA. Some neurons in Ammon's horn and dentate gyrus were selectively stained on the surface of their cell bodies with PNA. The present results show that lectins used distinguish different subpopulations of hippocampal neurons, indicating a new possible classification of hippocampal neurons based on their differences in glycoconjugates.

Animals↗
PubMed1991

Marked growth of a cerebral arteriovenous malformation: case report and review of the literature.

A case demonstrating the marked growth of an angiographically occult arteriovenous malformation is presented. A review of 58 cases in which an increase in the size of an arteriovenous malformation occurred suggested that the patient's initial age may have had an important role in such growth and that both the age and the duration of follow-up were related to the extent of growth. Follow-up neuroradiological examinations are thought to be necessary for patients who have had an episode of intracranial hemorrhage of unknown cause during childhood, even if the initial angiograms revealed no vascular lesion.

Adolescent↗
PubMed1991

Transantral ligation of the maxillary artery for refractory epistaxis. A case report.

A case of severe arterial epistaxis treated by transantral ligation of the maxillary artery is reported. A 66-year-old woman had recurrent left sided epistaxis from the posterior nasal cavity which was difficult to control by conventional nasal packing methods. Selective angiography was performed to identify the arterial flow patterns and site of bleeding which was confirmed to be the descending palatine artery. Following radiographical examination, ligation and clipping of the maxillary artery and its branches was performed with transantral approach under general anesthesia. No further epistaxis occurred after the ligation. This surgical procedure seems to be relatively simple and highly effective in the management of refractory epistaxis.

Aged↗
PubMed1991

Endoscopic findings in carcinoid tumor of the duodenum.

The endoscopic findings in six patients with carcinoid tumor of the duodenum were analyzed. Radiographic and endoscopic examinations revealed a smooth and round elevation (measuring 5-20 mm in diameter) in the duodenal bulb. In three patients, the lesion was accompanied by an irregularly shaped erythematous depression, a characteristic endoscopic finding of this tumor. Because the endoscopic forceps biopsy technique led to an accurate diagnosis, we wish to stress the clinical value of the endoscopic modalities.

Adult↗
PubMed1990

[Thin-section computed tomography of the normal minor fissure].

The minor fissure was studied with thin computed tomographic (CT) sections (2 mm thickness, 3 mm interval) in 50 patients. It showed high density line or area in all patients. In nine patients CT sections were not obtained through the all region of the minor fissure. Of other 41 patients the fissure was complete in 12 (29%), slightly incomplete in 18 (44%), half incomplete in 7 (17%), and considerably incomplete in 4 (10%). The upper surface of the middle lobe appeared to be upwardly convex in all 50 patients. The location of the highest portion of the minor fissure was hilar in 12 (24%) of 50 patients, medial 1 (2%), anterior 0 (0%), lateral 8 (16%), posterior 3 (6%), dorsal 10 (20%), central 12 (24%), others 2 (4%), and indeterminate 2 (4%). The minor fissure was higher medially than laterally in 22 (44%) patients, and higher posteriorly than anteriorly in 40 (80%) patients. The lowest portion of the minor fissure was anterior in 20 (40%) patients, lateral in 4 (8%), and posterior 3 (6%). The anterior vein of the anterior segment of the right upper lobe (V3b) came in contact with the minor fissure in 20 (40%) patients. In 18 (90%) of these 20 patients minor fissure medial to V3b was incomplete partially. Three dimensional reconstruction image of the minor fissure improved understanding of the anatomy. Familiarity with the anatomic detail of the minor fissure and with variations in the relationships of the upper and middle lobes is useful in localization or extension of a lesion.

Adult↗
PubMed1990

Chronological evaluation of acute traumatic intracerebral haematoma.

Serial computed tomographic (CT) studies were performed in 48 patients with brain contusion. Traumatic intracerebral haematoma (TIH) had developed within 6 hours in 56% of the cases, within 12 hours in 81% and 100% within 24 hours from the onset. TIH reached its maximal size in 84% of the cases within 12 hours. The incidence of the appearance of TIH from brain contusion was 52%. The performance of frequent CT examination within 24 hours following head injury would help to lower the mortality rate of such trauma.

Brain Injuries↗