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Biomedical subjects

K Ono

Publications and source records attributed to K Ono.

At least 19 recordsLinked to original sources
PubMed1992

Histochemical study of the lumbar colonic nerve supply to the internal anal sphincter and its physiological role in dogs.

The sympathetic innervation of the internal and sphincter (IAS) and its physiological role in maintaining sphincter tone were histochemically and mechanically studied in dogs anesthetized with pentobarbital sodium. Numerous catecholamine-fluorescent nerve fibers with varicosities were identified in the IAS of normal dogs. Such fibers were markedly reduced at one week and one month after resection of the hypogastric nerves (HGNs) or the lumbar colonic nerve (LCN), and disappeared after combined HGN and LCN resection. IAS tone decreased to 37.2% of baseline at 1 h after LCN resection and to 69.9% after HGN resection. It returned to the preoperative level at one week and one month after resection. The restored IAS tone was decreased again by acute transection of the previously intact HGNs or LCN. Combined LCN and HGN resection also caused a marked reduction of IAS tone (36.9%) at 1 h after the procedure, and was then restored to the preoperative level with time. The restored tone was not decreased by phentolamine administration. These findings confirmed that both the LCN and the HGN innervate the IAS and play a physiological role in the development of resting tone. The restoration of IAS tone after denervation may be due to intrinsic myogenic properties of the sphincter.

Acetylcholine↗
PubMed1992

Magnocellular neurosecretory neurons with ferritin-like immunoreactivity in the hypothalamic supraoptic and paraventricular nuclei of the rat.

Immunohistochemistry for rat liver ferritin (FRT) revealed an intensive labeling in some structures of the rat brain. In the supraoptic (SON) and paraventricular (PVN) hypothalamic nuclei, almost all neurosecretory neurons with vasopressin (AVP)-like immunoreactivity were immunostained with FRT. After water deprivation, a marked enlargement of cell body and an immunoreactivity to transferrin receptors were found in AVP-, FRT- and double (AVP+FRT)-labeled neurons in the SON and PVN.

Animals↗
PubMed1992

Additional binding sites for the pyruvate dehydrogenase kinase but not for protein X in the assembled core of the mammalian pyruvate dehydrogenase complex: binding region for the kinase.

A standard resolution of the bovine kidney pyruvate dehydrogenase complex yields a subcomplex composed of approximately 60 dihydrolipoyl transacetylase (E2) subunits, approximately 6 protein X subunits, and approximately 2 pyruvate dehydrogenase kinase heterodimers (KcKb). Using a preparation of resolved kinase in which Kc much greater than Kb, E2-X-KcKb subcomplex additionally bound at least 15 catalytic subunits of the kinase (Kc) and a much lower level of Kb. The binding of Kc to E2 greatly enhanced kinase activity even at high levels of bound kinase. Free protein X, functional in binding the E3 component, did not bind to E2-X-KcKb subcomplex. This pattern of binding Kc but not protein X was unchanged either with a preparation of E2 oligomer greatly reduced in protein X or with subcomplex from which the lipoyl domain of protein X was selectively removed. The bound inner domain of protein X associated with the latter subcomplex did not exchange with free protein X. These data support the conclusion that E2 subunits bind the Kc subunit of the kinase and suggest that the binding of the inner domain of protein X to the inner domain of the transacetylase occurs during the assembly of the oligomeric core. Selective release of a fragment of E2 subunits that contain the lipoyl domains (E2L fragment) releases the kinase (M. Rahmatullah et al., 1990, J. Biol. Chem. 265, 14,512-14,517). Sucrose gradient centrifugation yielded an E2L-kinase fraction with an increased ratio of the kinase to E2L fragment. A monoclonal antibody specific for E2L was attached to a gel matrix. Binding of E2L fragment also led to specific binding of the kinase. Extensive washing did not reduce the level of bound kinase. Thus, the kinase is tightly bound by the lipoyl domain region of E2.

Acetyltransferases↗
PubMed1992

Collagen gene expression during chondrogenesis from chick periosteum-derived cells.

Chick periosteum-derived cells, which do not enter the chondrogenic cell lineage during normal bone development and growth, exhibit chondrogenic potential in high cell density culture conditions. In such cultures, collagen gene expression was temporally analyzed at the mRNA level by a reverse transcription PCR (RT-PCR) procedure, which showed that alpha 1(II) and alpha 1(IX) collagen mRNAs are coordinately increased, coincident with the onset of overt chondrogenesis, and subsequently decreased as chondrocytes exhibited hypertrophic characteristics. alpha 1(X) collagen mRNA was detected well before the onset of chondrogenesis and markedly increased along with the hypertrophic change. For alpha 2(I) collagen, both the bone/tendon form and the cartilage form of mRNA were detected throughout the culture period. This culture system provides an experimental vehicle capable of investigating the molecular events involved in the full range of chondrogenic differentiation starting from uncommitted periosteum-derived mesenchymal stem cells.

Animals↗
PubMed1992

Site-specific DNA cleavage by mammalian DNA topoisomerase II induced by novel flavone and catechin derivatives.

Four naturally occurring flavones (baicalein, quercetin, quercetagetin and myricetin) and two novel catechins [(-)-epicatechin gallate and (-)-epigallocatechin gallate, from the tea plant Camellia sinensis], which are known inhibitors of reverse transcriptase, were shown to induce mammalian topoisomerase II-dependent DNA-cleavage in vitro. The flavones differed from the catechins in causing unwinding of duplex DNA, but both classes of compound induced enzymic DNA breakage at the same sites on DNA. Moreover, the cleavage specificity was the same as that for the known intercalator 4'-(acridin-9-ylamino)methanesulphon-m-anisidide, suggesting that these agents trap the same cleavable complex. Analysis of some 30 flavonoid compounds allowed elucidation of the structure-function relationships for topoisomerase II-mediated DNA cleavage. For flavonoid inhibitors an unsaturated double bond between positions 2 and 3 of the pyrone ring and hydroxy groups at the 5, 7, 3' and 4' positions favoured efficient cleavage. Hydroxy substitutions could be tolerated at the 3, 6 and 5' positions. Indeed, the absence of substituents at the 3', 4' and 5' positions could be compensated by a hydroxy group at position 6 (baicalein). Similar requirements have been reported for flavonoid inhibitors of protein kinase C that act competitively with ATP, suggesting interaction with a conserved protein feature. Formation of the cleavable complex is a cytotoxic lesion that may contribute to the growth-inhibitory properties of flavones observed for three human tumour cell lines. These results are discussed in regard to the selectivity of antiviral agents.

Animals↗
PubMed1992

Abnormal expression of embryonic neural cell adhesion molecule (N-CAM) in the developing mouse cerebellum after neonatal administration of cytosine arabinoside.

We have previously found that neonatal administration of cytosine arabinoside (Ara-C) induces cerebellar malformation, including arrest of granule cell migration and destruction of glial palisade. In the present study, the expression of neural cell adhesion molecule (N-CAM) and its distribution were examined in the mouse malformed cerebellum induced by neonatal Ara-C administration. Western blot analysis demonstrated that, in the control group, the embryonic form of N-CAM (E-N-CAM) was expressed in the 7-day-old mouse (P7) cerebellum, but not in the P14 cerebellum which exhibited only the adult form of N-CAM (A-N-CAM). On the other hand, E-N-CAM was expressed in the Ara-C treated cerebellum not only at P7 but also at P14. Immunohistochemical studies revealed that E-N-CAM was observed in the area below the external granular layer (EGL) of the P7 cerebellum in both the control and Ara-C treated mice. In contrast, E-N-CAM immunoreactivity was found in the arrested EGL cells in the Ara-C treated cerebellum of P14 mice but not in the age-matched controls. Therefore, E-N-CAM was aberrantly expressed in the arrested EGL at P14. From the present and previous findings, it was speculated that the aberrant expression of E-N-CAM in the arrested EGL cells is attributed to abnormal cellular interactions, probably arrested EGL cell-to-Bergmann glia.

Animals↗
PubMed1992

Bone marrow changes in adjuvant-induced and collagen-induced arthritis. Interleukin-1 and interleukin-6 activity and abnormal myelopoiesis.

OBJECTIVE: To investigate the role of bone marrow in arthritis. METHODS: Bone marrow changes over time were investigated in rats with adjuvant-induced and collagen-induced arthritis, using bioassay techniques and histologic analysis. RESULTS: In both animal models, bone marrow interleukin-1 and interleukin-6 activity began to rise before the onset of arthritis and increased in relation to the progression of arthritis. Enhanced myelopoiesis in the bone marrow was noted in conjunction with the increased cytokine activity. CONCLUSION: Bone marrow changes such as those demonstrated in this study may be common to various models of induced arthritis and may have an important role in the pathogenesis of this disease.

Animals↗
PubMed1992

Bone mineral density in the proximal femur and hip fracture type in the elderly.

Bone mineral density (BMD) in the contralateral proximal femur in 100 female elderly patients with hip fracture and the 35 controls without hip fracture were investigated using dual-photon absorptiometry. The hip fracture patients were divided into intracapsular fracture (n = 53) and extracapsular fracture (n = 47) groups, and these two groups were further divided into five subgroups according to fracture site: intracapsular fracture type 1 (transcervical fracture, n = 29) and type 2 (subcapital fracture, n = 24); extracapsular fracture type 1 (intertrochanteric line fracture, n = 13), type 2 (pertrochanteric fracture, n = 28), and type 3 (combined type of pertrochanteric and subtrochanteric fracture, n = 6). The intracapsular fracture group showed BMD values similar to those of controls; the extracapsular fracture group showed significantly lower BMD values than controls. When these two were subclassified into five subgroups, different results were seen in terms of BMD value in the proximal femur and fracture types; intracapsular fracture type 1 showed BMD values equivalent to those of controls; on the other hand, type 2 showed significantly lower BMD value than controls, and the BMD distribution in the proximal femur among the extracapsular fracture subgroups 1-3 differed, although all of them showed significantly lower BMD values than controls. The degree of trauma causing the fractures was also assessed according to available anamnestic data, but no significant difference was found in trauma tendency between the intra- and the extracapsular fracture group or among the subgroups in each group.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1992

Slow release of anticancer drugs from porous calcium hydroxyapatite ceramic.

We have developed a new delivery system for sustained release of an anticancer drug (cis-platinum) by enclosure into blocks of porous calcium hydroxyapatite ceramic. The slow release of this drug from this system was confirmed in in vitro experiments. When this system was implanted into normal back muscle, or the tibia, sustained release of cis-platinum was observed during a 12-week period after implantation. The diffusion rate of cis-platinum into blood and other organs (liver, kidney, brain) was less than 10% of that at the implanted site. This delivery system placed into experimental tumors of mice also showed a uniform release of anticancer drug for more than 3 months. Inhibition of tumor growth was more marked after local implantation of this system than after intraperitoneal administration of cis-platinum. These results indicate that this new approach to a drug delivery system may well have an important role in cancer chemotherapy. In bone tumors it is attractive because the mechanical strength of calcium hydroxyapatite ceramic permits partial surgical excision and replacement of the bone defect at the same time.

Animals↗
PubMed1992

Bethanechol and a G-protein activator, NaF/AlCl3, induce secretory response in Paneth cells of mouse intestine.

Paneth cells located at the bottom of intestinal crypts may play a role in controlling the bacterial milieu of the intestine. Using morphometry to clarify the secretory mechanism of the Paneth cells, we studied the ultrastructural changes in mouse Paneth cells produced following intra-arterial perfusion with Hanks' balanced salt solution containing a cholinergic muscarinic secretagogue (bethanechol), a neuroblocking agent (tetrodotoxin), or a G-protein activator (NAF/AlCl3). Bethanechol (2 x 10(-4) mol/l) induced Paneth-cell secretion. Many Paneth cells massively exocytosed their secretory material into the crypt lumen; the enhanced secretion caused degranulation and vacuole formation. However, tetrodotoxin (2 x 10(-6) mol/l) did not prevent the bethanechol-enhanced secretion by the Paneth cells. NaF (1 x 10(-2) mol/l) and AlCl3 (1 x 10(-5) mol/l) induced massive exocytosis of the Paneth cells; the exocytotic figures were similar to those observed in mice stimulated by bethanechol. G-protein activation was followed by a sequence of intracellular events, resulting in exocytosis.

Aluminum↗
PubMed1992

Alumina ceramic prostheses for bone tumor surgery.

Between 1979 and 1990 reconstruction using a ceramic prosthesis with a polycrystal alumina segment and a monocrystal alumina stem was carried out in 65 patients after the resection of malignant or benign aggressive bone tumors. Resection of 18 osteosarcomas, 5 chondrosarcomas, 9 other sarcomas, 10 giant cell tumors, 20 metastatic bone tumors, and 3 other bone tumors was followed by replacement of 17 proximal femurs, 12 distal femurs, 12 proximal tibia, 11 proximal humeri, 3 distal radii, 5 midshafts of the long bone, 2 pelvises, and 3 other parts. Results were rated excellent in 4 cases, good in 43, fair in 13, and poor in 4. In the cases with benignly aggressive or low-grade malignant tumors and those with tumors of the proximal femur, proximal tibia, or midshaft, satisfactory results can be obtained. Four skin ulcers, three dislocations, three loosenings, two infections, and two breaks were noted. Close interfacing between the ceramic prosthesis and the bone was observed radiologically in all cases with cementless fixation except in cases with high-grade malignancies in the knee joint. These results demonstrate that the ceramic prosthesis can be beneficial for the management of patients with benignly aggressive or low-grade malignant bone tumors who have retained adequate muscle strength around the joint even after tumor resection.

Adolescent↗
PubMed1992

Effects of reactive oxygen intermediate scavengers on the antitoxoplasmic activity of activated macrophages.

Obioactin, Lonomycin A, muramyl dipeptide, and scavengers of hydrogen radicals and of singlet oxygen were used to study the participation of.OH and 1O2 in the killing of Toxoplasma in cultures of glycogen-induced peritoneal macrophages. Both the scavengers of OH (diazabicyclooctane and histidine) and those of 1O2 (mannitol and sodium benzoate) failed to inhibit the multiplication of Toxoplasma in macrophages that were incubated with either Obioactin, Lonomycin A, or MDP. The results of these experiments demonstrate the apparent lack of an inhibitory effect of.OH and 1O2 on the multiplication of Toxoplasma, whereas the scavengers alone inhibited the growth of the parasites.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1992

Personal computer system for ECG ST-segment recognition based on neural networks.

A personal computer system for electrocardiogram (ECG) ST-segment recognition is developed based on neural networks. The system consists of a preprocessor, neural networks and a recogniser. The adaptive resonance theory (ART) is employed to implement the neural networks in the system, which self-organise in response to the input ECG. Competitive and co-operative interaction among neurons in the neural networks makes the system robust to noise. The preprocessor detects the R points and divides the ECG into cardiac cycles. Each cardiac cycle is fed into the neural networks. The neural networks then address the approximate locations of the J point and the onset of the T-wave (T(on)). The recogniser determines the respective ranges in which the J and T(on) points lie, based on the locations addressed. Within those ranges, the recogniser finds the exact locations of the J and T(on) points either by a change in the sign of the slope of the ECG, a zero slope or a significant change in the slope. The ST-segment is thus recognised as the portion of the ECG between the J and T(on) points. Finally, the appropriateness of the length of the ST-segment is evaluated by an evaluation rule. As the process goes on, the neural networks self-organise and learn the characteristics of the ECG patterns which vary with each patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Systems↗
PubMed1992

Gradient expression of neural cell adhesion molecule (NCAM) in the pontine migratory stream of fetal rats.

Immunohistochemical localization of a neural cell adhesion molecule (NCAM) was examined in the subpial pontine migratory stream of the fetal rat with a monoclonal antibody specific for the rat NCAM, MAb-AF11. Although the pontine cell strand showed weaker expression of NCAM than the parenchymal areas of the brainstem, within the cell strand, NCAM-immunoreactivity was somewhat greater in the anterior part of the stream near the neurons' destination than the caudal part. The weak NCAM gradient in the pontine migratory stream may contribute to formation of the pontine cell strand and the basal pontine gray.

Animals↗
PubMed1992

Immunolocalization of alkaline phosphatase in osteoblasts and matrix vesicles of human fetal bone.

A monoclonal antibody raised against alkaline phosphatase (ALP) of human osteosarcoma was used to localize this enzyme in human fetal bone tissue. For light microscopy, the presence of alkaline phosphatase in osteoblasts and osteocytes was demonstrated by use of an avidin-biotin immunoperoxidase procedure. Electron microscopic immunolocalization was accomplished with an indirect immunoperoxidase method which revealed a concentration of the enzyme on matrix vesicle and osteoblast plasma membranes. In addition, many vesicular protrusions arising from areas of plasma membrane on the lateral surfaces of adjacent osteoblasts were strongly immunolabeled. Immunostaining for ALP was absent in vesicles which contained fine crystallites. Alkaline-phosphatase-rich matrix vesicles may play a significant role in the mineralization of the extracellular matrix.

Alkaline Phosphatase↗
PubMed1992

Potentially lethal damage repair by quiescent cells in murine solid tumors.

We investigated potentially lethal damage repair by quiescent tumor cells in vivo. SCC VII tumor-bearing C3H/He mice were irradiated after being given 10 injections of 5-bromo-2'-deoxyuridine (BUdR) to label all the proliferating cells in their tumors, and the tumors were then excised and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (Cyt-B, a cytokinesis blocker), and the micronucleus frequency in cells without BUdR labelling was determined using immunofluorescence staining to BUdR. The micronucleus frequency was then used to determine the surviving fraction of unlabelled cells on the basis of the regression line obtained for the micronucleus frequency and the surviving fraction of all tumor cells not labeled by BUdR, which can be regarded as the quiescent cells in a tumor for all practical purposes. Assessment performed 0, 3, 6, 9, and 24 hr after irradiation showed that quiescent cells had more potentially lethal damage repair capacity than the tumor cell population as a whole. Assays were also performed immediately after irradiation alone, 24 hr after the injection of cis-diamminedichloroplatinum(II) (CDDP), mitomycin C (MMC), or misonidazole [1-(2-nitro-1-imidazolyl)-3-methoxy-2-propanol] (MISO) following irradiation, and 24 hr after irradiation alone. It was found that CDDP and MISO (especially the latter) inhibited potentially lethal damage repair more strongly in quiescent cells than in the tumor cell population as a whole. This assay method thus appears to be quite useful for detecting the responses of quiescent tumor cells to various chemical agents.

Animals↗
PubMed1992

Hepatocyte response to continuous low dose-rate radiation in radioimmunotherapy assessed by micronucleus assay.

The response of hepatocytes to low dose-rate irradiation was examined in mice following the injection of radiolabelled monoclonal antibody. Mice were injected intravenously with an 131I-labelled monoclonal antibody 196-14 which recognizes CA125 antigen, and the effect of continuous low dose-rate irradiation on hepatocytes was assessed using the micronucleus assay. The frequency of micronuclei increased in a dose-dependent fashion, but it was lower than the frequency induced by conventional external X-rays which was determined immediately after the irradiation. A linear quadratic model (micronucleus frequency = aD+bD2+c) showed that the value of b decreased with low dose-rate irradiation from the radiolabelled antibody. It is concluded that the micronucleus assay is useful for the evaluation of the response of hepatocytes to irradiation in radioimmunotherapy.

Animals↗