Search PubMed⌕ Search

Biomedical subjects

K Hirose

Publications and source records attributed to K Hirose.

At least 109 records · Page 6Linked to original sources
PubMed2000

[A long-term follow-up case of multiple impacted teeth associated with large follicular cyst in maxilla].

Longitudinal record of a case of multiple impacted teeth associated with large follicular cyst in the right maxilla was presented. The patient was an 8-year-10-month-old girl whose chief complaint was delayed eruption of the right upper incisor. Clinical examination revealed a large follicular cyst in the right maxillary sinus, which greatly displaced teeth germs. Marsupialization followed by orthodontic extrusion successfully brought unerupted teeth into their positions. Greatly displaced upper right canine, which was as high as the floor of the orbit, erupted spontaneously after reduction of the lesion. During the subsequent years, the patient developed crowded dentition and reduced overbite, which needed additional orthodontic treatment with extraction of premolars. The patient was 26-years 8-months old upon completion of treatment. The surgical, orthodontic, and periodontological aspects of the case were reexamined. Marsupialization of dentigerous cysts can preserve impacted teeth, however, the outcome might be affected by several factors such as overall growth of facial bones.

Adult↗
PubMed2000

The effect of modified ultrafiltration in pediatric open heart surgery.

Since 1997 we have performed modified ultrafiltration (MUF) in pediatric open heart operations. To elucidate the clinical effects of MUF, patients under 20 kg in weight who underwent corrective open heart operation since 1997 are divided into 2 cohorts according to the enforcement of MUF (control group versus MUF group) retrospectively. Procedures, age, bodyweight, cardiopulmonary bypass (CPB) time, operation time, amount of donor blood use, postoperative inotrope dose, postoperative intubation time, and postoperative gas exchange capacity of lung expressed with respiratory index (RI) were compared between groups. Furthermore, a multiple linear regression analysis was performed to find independent correlates with postoperative RI. Finally scattergrams of intubation time and RI were drawn against several factors. In univariate analyses, the MUF group had significantly shorter intubation time and better RI. Multivariate analysis revealed that the enforcement of MUF was an independent correlate of postoperative RI. Analyses on the scattergrams revealed that the above mentioned favorable effects of MUF were prominent in the patients younger than 3 years or weighing less than 10 kg. We concluded that MUF had significant effects on pulmonary function preservation in pediatric open heart operations, especially for smaller children.

Body Weight↗
PubMed2000

[Factors in continuation of home health care for patients with intractable neurological diseases].

OBJECTIVE: This study was carried out to elucidate factors related to difficulty in continuing home health care and to investigate problems of the corresponding support system for patients with intractable neurological diseases. SUBJECTS AND METHODS: Subjects were 139 cases of amyotrophic lateral sclerosis (ALS), 376 cases of spino-cerebellar degeneration (SCD) and 1,048 cases of Parkinson's disease (PD) who were collected from the nationwide survey of health and social service needs of the patients with intractable diseases in 1995. Factors and problems related to limited activity due to diseases and necessity for medical care were analysed. The need for facilities of long-term care was also studied. RESULTS: The characteristic conditions of patients with ALS were shorter duration of the illness, higher percentage of conditions requiring medical care and disorders of swallowing or respiration and full nursing care in daily life compared with the other two diseases. The characteristics of PD were higher percentage of female and older age in both patients and their family caregivers. The proportion of cases for whom health care was judged to be prone to difficulty was 23.0% in ALS, 10.9% in PD and 7.2% in SCD, respectively. Regarding the factors related to difficulty in continuing home health care, conditions requiring medical care, the need for full nursing care in daily life, and the duration of the illness were recognized in ALS. In SCD, 5 factors, including conditions requiring medical care, the need for full nursing care in daily life, patients age greater than 65 years, the duration of the illness, and patients being nursed by their sons or daughters were detected. In PD, 4 factors, such as conditions requiring medical care, the need for full nursing care in daily life, the patients being nursed by persons other than the spouse, and the need of nursing care were found. CONCLUSION: These results suggest the necessity of social functions of medical care, nursing and family support that can be supplied at home effectively according to symptoms in progress, and the need for facilities of long-term care of patients for whom continuation of home health care may become difficult, which will work as a support system for long-term care of patients with intractable neurological diseases.

Amyotrophic Lateral Sclerosis↗
PubMed2000

[A case of lateral origin of the left internal mammary artery].

A 66 years old men, with left anterior descending coronary artery (LAD) stenosis and aortic valve stenosis, underwent coronary artery bypass grafting (CABG) to LAD with left internal mammary artery (LIMA) and aortic valve replacement. His postoperative course was uneventful. But, postoperative angiogram showed that his patent LIMA graft was originated from much lateral side of the left subclavian artery. Internal mammary artery is considered the most ideal graft for CABG, but its' anomality is not well known. We present this rare case with the anomalous origin of LIMA.

Aged↗
PubMed1999

Dynamic Ca2+ signalling in rat arterial smooth muscle cells under the control of local renin-angiotensin system.

1. We visualized the changes in intracellular Ca2+ concentration ([Ca2+]i), using fluo-3 as an indicator, in individual smooth muscle cells within intact rat tail artery preparations. 2. On average in about 45 % of the vascular smooth muscle cells we found spontaneous Ca2+ waves and oscillations ( approximately 0.13 Hz), which we refer to here as Ca2+ ripples because the peak amplitude of [Ca2+]i was about one-seventh of that of Ca2+ oscillations evoked by noradrenaline. 3. We also found another pattern of spontaneous Ca2+ transients often in groups of two to three cells. They were rarely observed and are referred to as Ca2+ flashes because their peak amplitude was nearly twice as large as that in noradrenaline-evoked responses. 4. Sympathetic nerve activity was not considered responsible for the Ca2+ ripples, and they were abolished by inhibitors of either the Ca2+ pump in the sarcoplasmic reticulum (cyclopiazonic acid) or phospholipase C (U-73122). 5. Both angiotensin antagonists ([Sar1,Ile8]-angiotensin II and losartan) and an angiotensin converting enzyme inhibitor (captopril) inhibited the Ca2+ ripples. 6. The extracellular Ca2+-dependent tension borne by unstimulated arterial rings was reduced by the angiotensin antagonist by approximately 50 %. 7. These results indicate that the Ca2+ ripples are generated via inositol 1,4, 5-trisphosphate-induced Ca2+ release from the intracellular Ca2+ stores in response to locally produced angiotensin II, which contributes to the maintenance of vascular tone.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1999

Dynamic studies of ototoxicity in mature avian auditory epithelium.

Hearing loss induced by ototoxicity is a worldwide problem despite the development of newer antibiotics and chemotherapy agents. The cellular mechanisms responsible for aminoglycoside-induced hearing loss are still poorly understood. We have developed two different methods of studying the dynamic cellular and subcellular changes in the chick auditory sensory epithelium that occur during hair cell death. The first study was performed in mature chicks after a single, high dose injection of gentamicin, which results in the rapid loss of all hair cells in the basal third of the cochlea. Chicks were sacrificed at discrete time points after drug treatment, and transmission electron microscopy was performed to study the ultrastructural changes in basal hair cells during the course of cell death. We noted various changes in the cell morphology including accumulation of cytoplasmic inclusion bodies, dispersion of the cytoplasmic polyribosomes, mitochondrial swelling, and cellular extrusion by 24 h after injection. The next two studies were performed using tissue cultures from mature avian auditory sensory epithelium. Cultured cells were labeled using vital fluorescent markers, and levels of intracellular calcium and reactive oxygen species within hair cells were studied following aminoglycoside exposure. We identified a dose-dependent increase in the levels of intracellular calcium, which was blocked by an inhibitor of voltage-gated calcium channels. We also found that levels of reactive oxygen species in hair cells greatly increased after exposure to gentamicin, and this response was blocked by two different antioxidants. These studies serve to identify key cellular and molecular changes in hair cells in response to ototoxic drugs. Further study of these processes may lead to a better understanding of how ototoxicity is induced and to potential preventative interventions.

Animals↗
PubMed1999

Three-dimensional structure of motor molecules.

Images, calculated from electron micrographs, show the three-dimensional structures of microtubules and tubulin sheets decorated stoichiometrically with motor protein molecules. Dimeric motor domains (heads) of kinesin and ncd, the kinesin-related protein that moves in the reverse direction, each appeared to bind to tubulin in the same way, by one of their two heads. The second heads show an interesting difference in position that seems to be related to the directions of movement of the two motors. X-ray crystallographic results showing the structures of kinesin and ncd to be very similar at atomic resolution, and homologous also to myosin, suggest that the two motor families may use mechanisms that have much in common. Nevertheless, myosins and kinesins differ kinetically. Also, whereas conformational changes in the myosin catalytic domain are amplified by a long lever arm that connects it to the stalk domain, kinesin and ncd do not appear to possess a structure with a similar function but may rely on biased diffusion in order to move along microtubules.

Binding Sites↗
PubMed1999

Anthropogenic radionuclides in seawater of the Far Eastern Seas.

Large quantities of radioactive wastes have been dumped in the Far Eastern Seas by the former Soviet Union and the Russian Federation, and small amounts of radioactive wastes have been dumped by Japan and the Republic of Korea. In order to investigate the concentrations of anthropogenic radionuclides in the nine dumping areas, a second expedition was conducted in 1995 by Japan, the Republic of Korea, the Russian Federation and IAEA, following the first expedition in 1994. The results show that 137Cs, 90Sr and 239 + 240Pu concentrations in surface and bottom waters at dumping areas do not significantly differ from the values observed in background areas, and from historical values. There is no clear effect of possible contamination due to radioactive waste dumping. The concentrations and water column inventories of 137Cs, 90Sr and 239 + 240Pu in the Far Eastern seas are controlled by physical oceanic processes such as horizontal transport and biogeochemical processes such as scavenging.

Cesium Radioisotopes↗
PubMed1999

Interleukin-1 receptor antagonist mRNA expression and the progression of gastric carcinoma.

Interleukin-1 receptor antagonist (IL-1ra), an endogeneous inhibitor of IL-1, plays an immunosuppressive role in vivo by blocking the proinflammatory effects of IL-1. In the present study, we examined whether IL-1ra expression in human gastric carcinoma correlates with tumor progression and/or metastatic potential. The reverse transcription-polymerase chain reaction was used to compare the expression of the secreted form of IL-1ra (sIL-1ra) and the intracellular form of IL-1ra (icIL-1ra) mRNA in tumor and corresponding benign tissue obtained from 38 patients with gastric carcinoma. The incidence of sIL-1ra mRNA expression was significantly higher in tumor (52%) than in corresponding benign tissue (18%) (P = 0.002). On the contrary, icIL-1ra mRNA was detected in all tumors and benign tissues. The expression of sIL-1ra mRNA by malignant tissue correlated positively with both lymph node metastasis (P = 0.008) and liver metastasis (P = 0.015). There was no association between tumor sIL-lra mRNA expression and other clinicopathologic factors. The degree of regional lymph node reaction, such as sinus histiocytosis, in tumors expressing sI-1ra mRNA was significantly weaker than that in tumors without sIL-1ra mRNA expression (5/20 vs. 12/18, P = 0.010). These results demonstrate that the altered expression of sIL-1ra by malignant tissue may be related to the progression of gastric carcinoma via modulating host immune response.

Adult↗
PubMed1999

Marked expression of glutathione S-transferase A4-4 detoxifying 4-hydroxy-2(E)-nonenal in the skin of rats irradiated by ultraviolet B-band light (UVB).

Enzyme, Western blot, and immunohistochemical analyses indicated that rat skin cytosol contained no detectable level of the homodimeric, alpha-class glutathione S-transferase (rGST) A4-4 which catalyzes the GSH conjugation of the toxic product, 4-hydroxy-2(E)-nonenal (HNE), nonenzymatically formed from n-6 polyunsaturated fatty acid residues of lipids by lipid peroxidation. Rats irradiated by single doses (4000-24,000 mJ/cm(2)) of ultraviolet B-band light (UVB, 200 mJ/cm(2)/min) markedly expressed rGSTA4-4 in the skin at a level one-fifth that of the liver in apparent specific activity toward HNE at a single dose of 24,000 mJ/cm(2). Skin rGSTA4-4 was isolated, purified to homogeneity, and identified with hepatic rGSTA4-4 by reverse-phase partition HPLC and by amino acid sequence analysis of its CNBr fission peptides. Immunohistochemistry with polyclonal antibody raised against rGSTA4-4 demonstrated the selective expression of rGSTA4-4 in epidermis and sebaceous glands localized in dermis after UVB irradiation.

Aldehydes↗
PubMed1999

Spatiotemporal dynamics of inositol 1,4,5-trisphosphate that underlies complex Ca2+ mobilization patterns.

Inositol 1,4,5-trisphosphate (IP3) is a second messenger that elicits complex spatiotemporal patterns of calcium ion (Ca2+) mobilization and has essential roles in the regulation of many cellular functions. In Madin-Darby canine kidney epithelial cells, green fluorescent protein-tagged pleckstrin homology domain translocated from the plasma membrane to the cytoplasm in response to increased concentration of IP3. The detection of translocation enabled monitoring of IP3 concentration changes within single cells and revealed spatiotemporal dynamics in the concentration of IP3 synchronous with Ca2+ oscillations and intracellular and intercellular IP3 waves that accompanied Ca2+ waves. Such changes in IP3 concentration may be fundamental to Ca2+ signaling.

Adenosine Triphosphate↗
PubMed1999

Inhibitory modulation of B cell receptor-mediated Ca2+ mobilization by Src homology 2 domain-containing inositol 5'-phosphatase (SHIP).

Src homology 2 domain-containing inositol 5'-phosphatase (SHIP) mediates inhibitory signals that attenuate intracellular Ca2+ mobilization in B cells upon B cell receptor (BCR) stimulation. To clarify the mechanisms affected by SHIP, we analyzed Ca2+ mobilization in the DT40 B cell line in which the SHIP gene was disrupted. In SHIP-deficient cells, Ca2+ transient elicited by BCR stimulation was more prolonged than that in control cells both in the presence and absence of extracellular Ca2+. Inositol 1,4, 5-trisphosphate production following BCR stimulation was enhanced in SHIP-deficient cells. In SHIP-deficient cells in comparison with the control cells, BCR stimulation in the absence of extracellular Ca2+ induced a greater degree of Ca2+ store depletion and the Ca2+ influx upon re-addition of extracellular Ca2+ was also greater. However, store-operated Ca2+ influx (SOC) elicited by thapsigargin-induced store depletion was not affected by SHIP. These results indicate that the primary target pathway of SHIP is the Ca2+ release from the stores, and that Ca2+ influx by the SOC mechanism is secondarily controlled by the level of Ca2+ in the stores without direct inhibition of SOC. In this way, SHIP may play an important role in ensuring the robust tuning of Ca2+ signaling in B cells.

Animals↗
PubMed1999

Influence of habitual smoking on gastric cancer by histologic subtype.

A comparative case-referent study was conducted using data from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC), with the aim of clarifying whether histologic subtypes of gastric cancer exhibit different risk-factor patterns of habitual smoking. Our study comprised 995 histologically confirmed gastric-cancer cases [460 differentiated (intestinal type), 527 non-differentiated (diffuse type) and 8 unclassified], identified via hospital cancer registry and surgical records, and 43,846 non-cancer outpatients at Aichi Cancer Center Hospital over the years 1988-1995. Odds ratios (ORs) were estimated by gender using logistic regression and adjusted for potential confounding factors. In males, a significantly increased OR of gastric cancer was observed for habitual smokers, and this was higher in the differentiated type than the non-differentiated type and in younger than in older age groups. Risk patterns were less clear in females. Our results suggest that habitual smoking is associated more likely with the differentiated type of gastric cancer, particularly in younger cases.

Adult↗
PubMed1999

Encoding of Ca2+ signals by differential expression of IP3 receptor subtypes.

Inositol 1,4,5-trisphosphate (IP3) plays a key role in Ca2+ signalling, which exhibits a variety of spatio-temporal patterns that control important cell functions. Multiple subtypes of IP3 receptors (IP3R-1, -2 and -3) are expressed in a tissue- and development-specific manner and form heterotetrameric channels through which stored Ca2+ is released, but the physiological significance of the differential expression of IP3R subtypes is not known. We have studied the Ca2+-signalling mechanism in genetically engineered B cells that express either a single or a combination of IP3R subtypes, and show that Ca2+-signalling patterns depend on the IP3R subtypes, which differ significantly in their response to agonists, i.e. IP3, Ca2+ and ATP. IP3R-2 is the most sensitive to IP3 and is required for the long lasting, regular Ca2+ oscillations that occur upon activation of B-cell receptors. IP3R-1 is highly sensitive to ATP and mediates less regular Ca2+ oscillations. IP3R-3 is the least sensitive to IP3 and Ca2+, and tends to generate monophasic Ca2+ transients. Furthermore, we show for the first time functional interactions between coexpressed subtypes. Our results demonstrate that differential expression of IP3R subtypes helps to encode IP3-mediated Ca2+ signalling.

Adenosine Triphosphate↗
PubMed1999

Characterization of the muscarinic receptor subtype that mediates the contractile response of acetylcholine in the swine myometrium.

The aim of the present study was to characterize the subtype of muscarinic receptor that mediates acetylcholine-induced contractions in the nonpregnant proestrus swine myometrium by means of mechanical, radioligand ([3H]quinuclidinyl benzilate) binding and biochemical (measurement of cyclic AMP) approaches. Acetylcholine (-logEC50, 6.12), oxotremorine-methiodide (6.47), methacholine (6.35), carbachol (6.18) and muscarine (6.33) caused contractile responses of the uterine circular muscle, with a similar maximum amplitude, but pilocarpine and McN-A-343 (4-(m-chlorophenyl-carbamoyloxy)-2-butynyltrimethylammonium) were ineffective in causing contraction. The contractile response to acetylcholine was antagonized by the following muscarinic receptor antagonists in a competitive manner (with pA2 values in parentheses): atropine (8.95), 4-diphenylacetoxy-N-methylpiperidine (4-DAMP, 8.83), tropicamide (7.07), himbacine (7.01), pirenzepine (6.42) and 11-[[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyri do[2,3 b][1,4]benzodiazepin-6-one (AF-DX116, 5.96). Electrical field stimulation (10 Hz) caused tetrodotoxin- and atropine-sensitive contractions in the circular muscle. All muscarinic receptor antagonists decreased the electrical field stimulation-induced contraction in a concentration-dependent manner. The order of inhibition (-logIC50) was 4-DAMP (8.35) > tropicamide (6.72) > himbacine (6.54) > pirenzepine (6.31)> AF-DX116 (6.13). Acetylcholine did not affect the cytoplasmic cyclic AMP level, regardless of the presence or absence of forskolin, suggesting the absence of functional muscarinic M2 and/or M4 receptors in the swine myometrium. The receptor binding study indicated that circular muscle layers of the swine myometrium contained a single class of [3H]quinuclidinyl benzilate binding site (Kd = 0.92 nM; Bmax = 126.6 fmol/mg protein). Specific binding was displaced by muscarinic receptor antagonists in the following order (with pKi value and Hill coefficient in parentheses): atropine (8.22 and 0.93) > 4-DAMP (8.18 and 0.94) > tropicamide (6.78 and 0.93) > pirenzepine (5.46 and 0.92) > AF-DX116 (5.12 and 0.94). The present results suggest that in circular muscle layers of the swine myometrium, exogenous and endogenous acetylcholine cause contraction through activation of muscarinic M3 receptors present on smooth muscle cells.

Acetylcholine↗
PubMed1999

Critical duration of intracellular Ca2+ response required for continuous translocation and activation of cytosolic phospholipase A2.

When cells are exposed to certain external stimuli, arachidonic acid (AA) is released from the membrane and serves as a precursor of various types of eicosanoids. A Ca2+-regulated cytosolic phospholipase A2 (cPLA2) plays a dominant role in the release of AA. To closely examine the relation between Ca2+ response and AA release by stimulation of G protein-coupled receptors, we established several lines of Chinese hamster ovary cells expressing platelet-activating factor receptor or leukotriene B4 receptor. Measurement of intracellular Ca2+ concentration ([Ca2+]i) demonstrated that cell lines capable of releasing AA elicited a sustained [Ca2+]i increase when stimulated by agonists. The prolonged [Ca2+]i elevation is the result of Ca2+ entry, because this elevation was blocked by EGTA treatment or in the presence of Ca2+ channel blockers (SKF 96365 and methoxyverapamil). cPLA2 fused with a green fluorescent protein (cPLA2-GFP) translocated from the cytosol to the perinuclear region in response to increases in [Ca2+]i. When EGTA was added shortly after [Ca2+]i increase, the cPLA2-GFP returned to the cytosol, without liberating AA. After a prolonged [Ca2+]i increase, even by EGTA treatment, the enzyme was not readily redistributed to the cytosol. Thus, we propose that a critical time length of [Ca2+]i elevation is required for continuous membrane localization and full activation of cPLA2.

Animals↗