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Biomedical subjects

K Kawai

Publications and source records attributed to K Kawai.

At least 55 records · Page 3Linked to original sources
PubMed2001

Inhibition of bacterial and glucan adherence to various light-cured fluoride-releasing restorative materials.

OBJECTIVES: This study investigated the potential plaque adhesion properties of various light-cured fluoride-releasing restorative materials by measuring the amount of adhering radiolabeled bacteria and glucan. METHODS: Three resin-modified glass ionomer cements (RMGI) and two polyacid-modified resin composites (compomer) were used in this study. As a control, one light-cured resin composite was added. Disk-shaped specimens were made following the manufacturers' recommendations and the respective surfaces were finished with a 600-grit abrasive paper. Streptococcus sobrinus B13 was selected as a cariogenic bacterial strain. The amount of bacteria and glucan adhered to these specimens were measured after 3, 8 and 24h incubations with radiolabeled cariogenic bacteria and sucrose. RESULTS: After 3 and 8h incubations, the amount of adhered bacteria and glucan was small and there were no significant differences among the restorative materials except in the resin composite. Although after 24h incubation the amounts of adhered bacteria and glucan, significantly increased on the RMGIs and compomers, these were still significantly less than the resin composite except one compomer. Although at 3h no good correlation was found between the contact angles and the amount of bacteria and glucans, the correlation coefficients were high at 8 or 24h. In addition, the coefficients for bacteria were always higher than those for glucan irrespective of the incubation times. CONCLUSIONS: After 24h resin-modified glass ionomer cements and compomers showed significantly smaller amounts of adhered bacteria and glucans compared to resin composite with an exception of glucan adherence on one compomer.

Acrylic Resins↗
PubMed2001

Homogeneous epithelial gamma delta T cell repertoire of the skin is shaped through peripheral selection.

In contrast to the T cell receptor (TCR) diversity of major alpha beta T cells in lymphoid tissues, epithelial T cells of the murine skin, called dendritic epidermal T cells (DETC), express exclusively an invariant gamma delta TCR. Fetal thymic precursors of DETC immigrate to the skin before birth, and in adult mice T cells expressing the canonical gamma delta TCR identical to that of DETC are not found in other lymphoid or epithelial tissues. Here, we show that DETC precursors migrate to the gut as well as to the skin during fetal periods, but preferentially survive and expand in the skin after birth. We propose that similar to the thymic selection of the diverse alpha beta T cell repertoire, 'peripheral selection' of the homogeneous epithelial gamma delta T cell repertoire may be mediated by TCR signaling upon the recognition of the self-ligand, because the ligand for the DETC TCR was expressed only in the skin.

Animals↗
PubMed2001

Hepatocellular carcinoma with blood supply from omental branches: treatment with transcatheter arterial embolization.

PURPOSE: To evaluate the usefulness of transcatheter arterial embolization (TAE) through the omental branch in the treatment of hepatocellular carcinoma (HCC) with blood supply from the omental branch. MATERIALS AND METHODS: Fifteen patients with HCC fed by the omental branch underwent TAE. All but one had previously undergone several therapies for HCC, including TAE. Three patients had intraperitoneal hemorrhage caused by ruptured HCC fed by the omental branch, and two necessitated emergency TAE. The technical success rate, therapeutic effect, and safety of TAE via the omental branch were evaluated. RESULTS: Twenty-six omental branches that fed HCC were observed angiographically. Attenuation or occlusion of the hepatic artery was observed in 80%. Nineteen omental branches (73%) could be successfully embolized. Hepatic hemostasis was achieved in all patients with ruptured HCC. Tumor recurred in 80% of patients who underwent successful TAE of the omental branch, and additional therapy was performed in six patients. Ten patients died after 2-26 months (mean, 8 mo). Five patients were alive for 3-13 months (mean, 7 mo). Severe complications were not observed in any patient. CONCLUSION: TAE of the omental branch is safe and has become technically feasible in almost all patients, but tumors frequently recur.

Aged↗
PubMed2001

Use of a catheter with a large side hole for selective catheterization of the inferior phrenic artery.

The authors report the use of a catheter with a large side hole in the catheterization of the right inferior phrenic artery (IPA) arising from the proximal portion of the celiac trunk. A 5-F catheter with a side hole on either the top or the right side of the superior portion near the tip was used in five patients with hepatocellular carcinoma fed by the right IPA, which could not be selected by a conventional coaxial technique. In all patients, a 3-F microcatheter was successfully advanced into the right IPA through the side hole of this catheter introduced into the celiac artery or the common hepatic artery.

Aged↗
PubMed2001

In vivo evidence that protease-activated receptors 1 and 2 modulate gastrointestinal transit in the mouse.

1. Protease-activated receptors (PARs) 1 and 2 modulate the gastric and intestinal smooth muscle motility in vitro. In the present study, we examined if activation of PAR-2 and PAR-1 could alter gastrointestinal transit in mice. 2. Intraperitoneal administration of the PAR-2-activating peptide SLIGRL-NH(2), but not the inactive control LSIGRL-NH(2), at 1 - 5 micromol kg(-1), in combination with the aminopeptidase inhibitor amastatin at 2.5 micromol kg(-1), facilitated gastrointestinal transit in a dose-dependent manner. The human PAR-1-derived peptide SFLLR-NH(2) and the specific PAR-1 agonist TFLLR-NH(2), but not the inactive control FSLLR-NH(2), at 2.5 - 10 micromol kg(-1), in combination with amastatin, also promoted gastrointestinal transit. 3. The Ca2+-activated, small conductance K+ channel inhibitor apamin at 0.01 micromol kg(-1) significantly potentiated the actions of SLIGRL-NH(2) and TFLLR-NH(2) at subeffective doses. 4. The increased gastrointestinal transit exerted by either SLIGRL-NH(2) at 5 micromol kg(-1) or TFLLR-NH(2) at 10 micromol kg(-1) was completely abolished by the L-type Ca2+ channel inhibitor verapamil at 61.6 micromol kg(-1). In contrast, the tyrosine kinase inhibitor genistein at 18.5 micromol kg(-1) failed to modify the effects of the agonists for PAR-2 or PAR-1. 5. These findings demonstrate that PAR-1 and PAR-2 modulate gastrointestinal transit in mice in vivo. Our data also suggest that the PAR-1-and PAR-2-mediated effects are modulated by apamin-sensitive K+ channels and are dependent on activation of L-type Ca2+ channels, but independent of tyrosine kinase. Our study thus provides novel evidence for the physiological and/or pathophysiological roles of PARs 1 and 2 in the digestive systems, most probably during inflammation.

Amino Acid Sequence↗
PubMed2001

Lectin cytochemistry of rat cerebral and cerebellar neuronal cells.

Lectin cytochemistry of normal rat central nervous system (CNS) was performed on formalin-fixed, paraffin-embedded sections by using 14 lectins and light and electron microscopy. Hippocampal neurons reacted positively with Griffonia (Bandeiraea) simplicifolia lectin I (GSL-I), Griffonia (Bandeiraea) simplicifolia lectin II (GSL-II) and Vicia villosa agglutinin (VVA); neurons in the cornu ammonis (CA) 2 region reacted positively with GSL-I and GSL-II, and neurons in the CA2 and CA3 regions reacted with VVA. Cortical neurons reacted positively with GSL-I and VVA. Cerebellar Purkinje cells and granule cells were reactive with Phaseolus vulgaris leukoagglutinin (PHA-L). Cerebellar nucleus neurons were also reactive with PHA-L and VVA. Reactivity with GSL-I, GSL-II, VVA and PHA-L was observed only on the neuronal cell surface. The present findings demonstrate the differences between cerebral and cerebellar neurons in reacting with glycoconjugates.

Animals↗
PubMed2001

Functional analysis of RET with Hirschsprung mutations affecting its kinase domain.

BACKGROUND AND AIMS: Many missense mutations in the RET proto-oncogene were found in familial and sporadic cases of Hirschsprung disease (HSCR). The aim of this study was to make clear the mechanisms of RET dysfunction by HSCR mutations identified in its kinase domain. METHODS: Ten kinase domain HSCR mutations were introduced into wild-type RET and constitutively activated RET with a multiple endocrine neoplasia 2A mutation, and the resulting mutant complementary DNAs were transfected into SK-N-MC primitive neuroectodermal tumor cells or NIH 3T3 fibroblast cells. The levels of activation of mutant RET and representative signaling molecules were investigated in the transfectants. RESULTS: E762Q, S767R, R972G, and M980T mutations partially impaired the RET kinase activity and the representative signaling pathways. In particular, these mutations severely impaired the phospholipase C-gamma signaling pathway in SK-N-MC cells. S765P, R873Q, F893L, R897Q, and E921K mutations resulted in a complete loss of the RET kinase activity. The P973L mutation markedly decreased the expression of the RET protein with normal kinase activity. CONCLUSIONS: Hirschsprung disease can result from these distant functional classes of kinase domain mutation of RET.

Cells, Cultured↗
PubMed2001

Successful radiosurgical treatment of lesional epilepsy of mesial temporal origin.

We report a case of successful radiosurgical treatment of lesional epilepsy of mesial temporal origin. A patient presented with a 2-year history of medically intractable complex partial seizures associated with a mesial temporal angioma. Interictal scalp EEG and MEG showed focal epileptiform activity around the lesion. 99mTc-HMPAO-SPECT and 18F-FDG-PET demonstrated depressed blood flow and glucose metabolism in the corresponding temporal lobe. The patient underwent gamma knife radiosurgery for the causative lesion with a low marginal dose of 18 Gy. After treatment, the partial attack ceased without shrinkage of the lesion or peri-lesional parenchymal radiation injury.

Adult↗
PubMed2001

Plasma brain natriuretic peptide as a novel therapeutic indicator in idiopathic dilated cardiomyopathy during beta-blocker therapy: a potential of hormone-guided treatment.

BACKGROUND: Plasma brain natriuretic peptide (BNP) is a sensitive and specific marker of left ventricular (LV) function. In the treatment of heart failure, especially in idiopathic dilated cardiomyopathy (IDC), beta-blocker (BB) therapy has been established as a powerful strategy. The purpose of this study was to analyze relationships between changes in BNP level and LV function during BB therapy in patients with IDC. METHODS: In 30 patients with IDC who had already received conventional therapy, measurement for plasma BNP and norepinephrine levels and echocardiographic indices were evaluated before and 2 and 6 months after carvedilol in 21 patients and at baseline and after 6 months in 9 patients who did not receive carvedilol. RESULTS: After 6 months carvedilol treatment significantly improved LV end-diastolic dimension (LVEDD) (65 +/- 8 to 61 +/- 8 mm) and LV ejection fraction (LVEF) (34% +/- 13% to 43% +/- 12%) with intergroup differences; it significantly decreased BNP (127 +/- 113 to 69 +/- 92 pg/mL) with no intergroup difference; however, it did not decrease norepinephrine. BNP correlated strongly with LVEDD, LVEF, and LV mass index in carvedilol-treated patients. The degree of change in BNP correlated with that in LVEDD or LVEF 6 months after carvedilol. All 14 patients with decreased or unchanged BNP levels showed an increase in LVEF, and 4 of 7 with a rise in BNP had decreased or unchanged LVEF. According to receiver operating characteristic analysis, the optimal BNP levels for detecting LVEF <35% before and after carvedilol were 75.5 and 69 pg/mL, respectively. CONCLUSION: Plasma BNP levels may accurately reflect alteration in LV function and structure and can be used as a therapeutic indicator for risk stratification in patients with IDC during BB therapy.

Adrenergic beta-Antagonists↗
PubMed2001

New method for divesting cobalt-chromium alloy castings: sandblasting with a mixed abrasive powder.

STATEMENT OF PROBLEM: Because the conventional divesting method for cobalt-chromium (Co-Cr) alloys is laborious, a more convenient method is desirable. PURPOSE: This study compared sandblasting with a mixed powder composed of aluminum oxide and glass beads to sandblasting with single powders (carborundum, aluminum oxide, and glass beads) when a Co-Cr casting was removed from the investment mold. MATERIAL AND METHODS: Rectangular plates with the 2 surfaces simulating the inner and outer surfaces of a removable partial denture framework were fabricated with Co-Cr alloys. Four kinds of sandblasting powders were used to remove the remnants of investment molds. Total time (seconds) required for each procedure was measured, as was the surface roughness (Ra) of each specimen after sandblasting. SEM was used to analyze the powders themselves and the sandblasted specimen surfaces. RESULTS: Glass beads alone and the mixed powder of aluminum oxide and glass beads generated a smoother surface compared with aluminum oxide and carborundum powders. The use of the mixed powder significantly reduced the time of the sandblasting procedure. SEM revealed that glass beads generated fewer scars, followed by the mixed powder and then aluminum oxide. The surface sandblasted by carborundum powder was always the roughest. CONCLUSION: Sandblasting Co-Cr castings with the mixed powder effectively decreased treatment time and resulted in smooth, clinically acceptable casting surfaces.

Aluminum Oxide↗
PubMed2001

Formation of viable but non-culturable state (VBNC) of Aeromonas hydrophila and its virulence in goldfish, Carassius auratus.

In this study we investigated the viable but non-culturable (VBNC) state of Aeromonas hydrophila and its virulence in goldfish. Aeromonas hydrophila cultured in a 0.35% NaCl solution at pH 7.5 and at 25 degrees C for 50 days showed the VBNC state. In the VBNC state we were unable to detect viable bacteria by the plate count method but we did find 10(4) cells/ml by the direct viable count microscopical method after staining with fluorescein diacetate and ethidium bromide. The virulence comparison in goldfish showed that bacteria cultured at 25 degrees C for 1 day in a 0.35% NaCl solution were more virulent than bacteria cultured for 28 days. VBNC bacteria showed lower virulence in goldfish compared to 28-day-cultured bacteria by intraperitoneal injection. The results from the study suggest that A. hydrophila can remain in the aquatic environment for prolonged periods in the VBNC state but those cells are not pathogenic to goldfish.

Aeromonas hydrophila↗
PubMed2001

Breast reconstruction using a deepithelialized rectus abdominis musculocutaneous flap.

There are many methods for breast reconstruction. Using implants can achieve good results without conspicuous scarring, but this method has disadvantages, such as infection, exposure, and capsular contracture. The rectus abdominis musculocutaneous (RAM) flap has become a standard technique because of its safety and abundant volume, but its main problem is the lack of a color and texture match between the skin paddle and the skin around the flap. To overcome such shortcomings, the authors perform breast reconstruction using tissue expansion and a RAM flap. First a tissue expander is inserted superficially to the pectoralis major muscle at the time of or after mastectomy, and is expanded to a size larger than the contralateral breast. The expander is replaced with the deepithelialized RAM flap. Scar revision is performed if the expander is inflated satisfactorily. The authors used this technique in 11 patients and obtained good results without severe complications.

Adult↗
PubMed2001

Proliferation and functional changes of pancreatic gastrin cells in neonatal rat.

INTRODUCTION: Although gastrin cells are not found in the adult pancreas, they are found transiently in the neonatal pancreas. It has been suggested that gastrin may play a role in pancreatic development. However, cell kinetics as well as the fate and the role of gastrin cells are not clear. METHODOLOGY: Proliferation and functional changes of pancreatic gastrin cells in neonatal Wister rats were studied by immunohistochemistry and [(3)H]thymidine autoradiography. RESULTS: Numbers of pancreatic gastrin cells in neonatal rats showed a peak immediately after birth and then decreased rapidly. Gastrin cells were observed within approximately 2 weeks after birth in islets and within approximately 4 weeks after birth among exocrine cells. In contrast with the decrease of gastrin cell numbers, numbers of duodenal cholecystokinin cells increased remarkably after 7 days of age. Proliferative activity of acinar cells showed two peaks at age 2 days and 9 days. Despite a decrease in gastrin cell numbers, gastrin cells maintained a certain degree of proliferative activity. The "re-staining method" for gastrin and insulin revealed that immunoreactive cells for both gastrin and insulin were rarely found a few days after birth. CONCLUSION: These results suggest that pancreatic gastrin cells do not die off or change to another type of endocrine cell and that some gastrin cells change to insulin cells.

Aging↗
PubMed2001

Three-dimensional imaging of hormone-secreting cells and their microvessel environment in estrogen-induced prolactinoma of the rat pituitary gland by confocal laser scanning microscopy.

This study focused on the three-dimensional imaging of hormone-secreting cells and their microvascular environment in estrogen-induced prolactinoma of the rat pituitary gland. Adult female Wistar-Imamichi rats were injected with estradiol dipropionate and killed 7 weeks later. Some rats given estrogen for 7 weeks also were injected with bromocriptine before killing. To obtain a detailed three-dimensional image of microvessels, dialyzed fluorescein isothiocyanate (FITC)-conjugated gelatin was injected into the left ventricle of the rat heart. After the perfusion, the pituitary glands were resected and subjected to immunohistochemistry (IHC). To evaluate the effects of estrogen and bromocriptine, IHC was performed with antibodies against prolactin (PRL), adrenocorticotropic hormone (ACTH), and growth hormone (GH). With the combination, microvessels and cells containing PRL, ACTH, and GH could be clearly identified by confocal laser scanning microscopy (CLSM). The PRL cells increased in number and became hypertrophic after prolonged exposure to estrogen. With bromocriptine administration after estrogen treatment, however, PRL cells decreased in number and became atrophic. The current study revealed that estrogen and bromocriptine had significant effects on PRL secretion and the microvascular environment. Therefore, this technique (FITC injection and IHC) with CLSM is suitable for the three-dimensional imaging of hormone-secreting mechanisms under various conditions.

Adrenocorticotropic Hormone↗
PubMed2001

Gene expression profiles during the initial phase of salt stress in rice.

Transcript regulation in response to high salinity was investigated for salt-tolerant rice (var Pokkali) with microarrays including 1728 cDNAs from libraries of salt-stressed roots. NaCl at 150 mM reduced photosynthesis to one tenth of the prestress value within minutes. Hybridizations of RNA to microarray slides probed for changes in transcripts from 15 min to 1 week after salt shock. Beginning 15 min after the shock, Pokkali showed upregulation of transcripts. Approximately 10% of the transcripts in Pokkali were significantly upregulated or downregulated within 1 hr of salt stress. The initial differences between control and stressed plants continued for hours but became less pronounced as the plants adapted over time. The interpretation of an adaptive process was supported by the similar analysis of salinity-sensitive rice (var IR29), in which the immediate response exhibited by Pokkali was delayed and later resulted in downregulation of transcription and death. The upregulated functions observed with Pokkali at different time points during stress adaptation changed over time. Increased protein synthesis and protein turnover were observed at early time points, followed by the induction of known stress-responsive transcripts within hours, and the induction of transcripts for defense-related functions later. After 1 week, the nature of upregulated transcripts (e.g., aquaporins) indicated recovery.

Adaptation, Physiological↗
PubMed2001

Changes in the cell structure of Flavobacterium psychrophilum with length of culture.

Flavobacterium psychrophilum, the pathogen of bacterial cold-water disease, causes serious problems in ayu Plecoglossus altivelis culture. This study investigated the effect of the culture period of F. psychrophilum and on the structure of its cells. From the SDS-PAGE of total proteins of cellular components, much difference was found between the 36 hr culture and the 48 and 72 hr cultures. A SEM observation of the cells showed many fragments, especially on the cell surface of the 36 hr culture. These fragments consisted of an outer membrane, seen by TEM observation, and may contain substances causing the virulence. Specific proteins observed by the SDS-PAGE and fragments in the 36 hr culture may be related to the virulence of F. psychrophilum.

Animals↗
PubMed2001

Cloning, expression, and characterization of a family 52 beta-xylosidase gene (xysB) of a multiple-xylanase-producing bacterium, Aeromonas caviae ME-1.

A lambda phage genomic library of Aeromonas caviae ME-1, a multiple-xylanase-producing bacterium, was screened for xylan degradation activities. We isolated one clone, B65, which had weak xylanase activity, by the DNS method, but gave no visible bands on zymogram assay using SDS-xylan-PAGE. Based on TLC analyses of enzymatic products and some glycosidase assays using p-nitrophenyl substrates, we established that pB65 encodes a beta-xylosidase gene. In the nucleotide sequence analysis, we found a 2190-bp open reading frame (ORF) named xysB. XysB protein is similar to some beta-xylosidases, which are categorized in the glycosyl hydrolase family 52. Another ORF (xyg), that showed similarity to the family 67 alpha-glucuronidase, was also found downstream of the xysB gene. The xysB ORF and its promoter region were cloned into the pT7-Blue vector and the transformant cells had beta-xylosidase activity. The relative molecular mass were estimated to be 75 kDa by SDS-PAGE and 159 kDa by gel filtration. These data showed that XysB has a dimeric structure of 80,697 Da subunits. This enzyme showed optimal activity at 50 degrees C and pH 6.0. It was stable below 40 degrees C and pH 5-8. The Km and Vmax were calculated to be 0.34 mM and 33 nmol x min(-1) x microg(-1), respectively. This enzyme also showed transglycosylation activity against X3 and produced X4 and X5.

Aeromonas↗