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Biomedical subjects

N Kitamura

Publications and source records attributed to N Kitamura.

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

Genomic structure and chromosomal localization of the human hepatocyte growth factor activator inhibitor type 1 and 2 genes.

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) and type 2 (HAI-2) are recently discovered Kunitz-type serine protease inhibitors which can be purified and cloned from human stomach cancer cell line MKN45 as specific inhibitors against hepatocyte growth factor activator (HGFA). HAI-2 was identical with the protein originally reported as placental bikunin. Both proteins contain two Kunitz inhibitor domains (KDs), of which the first domain (KD1) is mainly responsible for the inhibitory activity against HGFA, and are expressed ubiquitously in various tissues. In this study, we cloned the genes coding for these two structurally similar proteins by screening of human genomic bacterial artificial chromosome (BAC) library and their genomic structures were compared. HAI-1 and -2 genes consist of 11 and 8 exons spanning 12 kbp and 12.5 kbp, respectively. Three exons were inserted between KD1 and KD2 of each gene, of which the middle one was the low-density lipoprotein (LDL) receptor-like domain (HAI-1) and the testis specific exon (HAI-2). Apparently homologous regions between HAI-1 and -2 were not found in 5'-flanking region and neither TATA nor CAAT box was present. The genes were mapped to chromosome 15q15 (HAI-1) and 19q13.11 (HAI-2). These results suggested that although HAI-1 and -2 genes might be derived from same ancestor gene, they acquired distinctive in vivo roles during their evolution.

Amino Acid Sequence↗
PubMed2000

Differential localization of immunoreactive alpha- and beta-subunits of S-100 protein in feline testis.

This study investigates the differential localization of the alpha-subunit (S100-alpha) and the beta-subunit (S100-beta) of the S-100 protein in the feline testis, using immunohistochemistry with polyclonal antibodies to bovine S-100 protein (S-100) and monoclonal antibodies to bovine S100-alpha and S100-beta. Appreciable differences were observed in the cellular localization of the immunoreactivity of each subunit. S-100 was observed in the Sertoli cells, the epithelial cells of the transitional segment of the seminiferous tubules, Leydig cells and the peritubular cells of the seminiferous tubules, but was not observed in the epithelial cells of straight tubules and the rete testis or in the endothelial cells of blood and lymph vessels. S100-alpha immunoreactivity was localized in Sertoli cells, peritubular cells and the epithelial cells of the terminal segment of the tubules, whereas S100-beta immunoreactivity was localized in Leydig cells. The differential localization of the alpha- and beta-subunits of the S-100 protein in the feline testis suggests that this protein is multifunctional and be useful as an investigative tool in studying feline testis function.

Animals↗
PubMed2000

Immunohistochemical localization of neuropeptides in bovine pancreas.

The occurrence and density of distribution of nerves and endocrine cells that are immunoreactive for neuropeptides in the bovine pancreas were studied by immunohistochemistry. The six neuropeptides localized were galanin (GAL), substance P (SP), methionine-enkephalin (MENK), neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP). The exocrine pancreas was shown to have an appreciable number of GAL- and SP-immunoreactive nerve fibres but few fibres showing immunoreactivity for VIP and CGRP. Numerous MENK-, GAL-, SP-, and NPY-immunoreactive nerve fibres were seen in the endocrine portion of the pancreas. Nerve cell bodies in the intrapancreatic ganglia showed immunoreactivity for all of the neuropeptides except CGRP. Endocrine cells showing immunoreactivity for GAL and SP were observed in the large islets and islets of Langerhans, respectively. The present results indicate a characteristic distribution of neuropeptides in the bovine pancreas, which may regulate both exocrine and endocrine secretions of pancreas.

Aging↗
PubMed2000

Immunohistochemical study on the distribution of endocrine cells in the gastrointestinal tract of the babirusa, Babyrousa babyrussa (Suidae).

The distribution and relative frequency of endocrine cells in the gastrointestinal tract of the babirusa were studied immunohistochemically using the avidin-biotin-peroxidase complex method. Thirteen types of gut endocrine cells were detected; they were immunoreactive for chromogranin, serotonin, somatostatin, gastrin, bovine pancreatic polypeptide (BPP), glucagon, secretin, cholecystokinin (CCK), methionine-enkephalin-Arg6-Gly7-Leu8 (MENK8), motilin, gastric inhibitory polypeptide (GIP) and peptide tyrosine tyrosine (PYY). Cells that were immunoreactive for chromogranin, serotonin, somatostatin and glucagon were found in all portions of the gastrointestinal tract. MENK8-immunoreactive cells were observed in the stomach and small intestine. Gastrin-immunoreactive cells were detected in the pyloric region and duodenum. PYY-immunoreactive cells were found in the small and large intestine. Cells immunoreactive for motilin, CCK, GIP, and secretin were observed in the proximal small intestine and those immunoreactive for neurotensin were found only in the ileum. Although the distribution pattern of endocrine cells in the gastrointestinal tract of babirusa was similar to those reported for pig, restricted distribution of several endocrine cells, gastrin, BPP, MENK8, motilin, CCK, GIP, secretin and neurotensin and wider distribution of glucagon and PYY were observed in the babirusa. The unexpected presence of MENK8 in all glandular regions of the stomach and PYY in the small intestine was also noted. The distribution of gut endocrine cells might be related to the regulatory characteristics of the babirusa digestive tract.

Animals↗
PubMed2000

Galanin-like immunoreactive endocrine cells in bovine pancreas.

Pancreata of fetal, neonatal and adult cattle were studied immunohistochemically for galanin. The results revealed galanin-like immunoreactivity both in the endocrine cells and in the neural elements. The galanin-like immunoreactive endocrine cells (Gal-LIEC) were confined to the large islets, and were not observed in the islets of Langerhans and exocrine pancreas. They were first detected at the third prenatal month. Their developmental profile showed an increase from fetal to early neonatal stage with a subsequent decrease towards adulthood. The considerable number of Gal-LIEC from late prepartum to early postpartum stage may imply functional significance of galanin during the perinatal development of cattle. Coexistence of galanin and insulin was also observed which may suggest autocrine interaction between the 2 hormones.

Animals↗
PubMed2000

Prognostic value of mitotic metaphase rate in oesophageal cancer.

OBJECTIVE: To assess the prognostic value of the mitotic metaphase rate in patients with oesophageal cancer. DESIGN: Retrospective study. SETTING: University hospital, Japan. SUBJECTS: 41 patients with oesophageal cancer. INTERVENTIONS: We calculated the ratio of mitotic metaphase to anaphase cells among tumour cells in sections stained with haematoxylin and eosin, a ratio that shows the status of mitotic metaphase-anaphase transition. The DNA ploidy pattern was examined by flow cytometry. MAIN OUTCOME MEASURE: Correlation between survival and mitotic metaphase rate. RESULTS: A high mitotic metaphase rate was correlated with vascular invasion and is expected to be a useful prognostic factor. DNA diploidy combined with a low rate was an independent favorable prognostic factor. CONCLUSION: Mitotic metaphase rate is a useful index of malignant potential, independent of DNA ploidy. It can distinguish high malignant potential from low in a diploid tumour, which has a poor prognosis that is equal to that of the aneuploidy tumour.

Aged↗
PubMed2000

Improvement of portal flow and hepatic microcirculatory tissue flow with N-acetylcysteine in dogs with obstructive jaundice produced by bile duct ligation.

OBJECTIVE: To find out if N-acetylcysteine (NAC) would improve hepatic circulation in dogs with obstructive jaundice. DESIGN: Open laboratory study. SETTING: University hospitals, Japan and France. MATERIALS: 14 male beagle dogs and 10 male Wistar rats. INTERVENTIONS: Obstructive jaundice was produced by ligation of the common bile duct (CBD) for 7 days in both dogs and rats. Either 5% dextrose (control group, n = 7) or NAC (NAC group, n = 7) was given to dogs. Sinusoidal endothelial cells were obtained from rats after ligation by elutriation, and varying amounts of NAC were given. MAIN OUTCOME MEASURES: The volumes of portal blood flow and hepatic microcirculatory tissue flow were reduced after ligation of the CBD, but those increased after NAC had been given to dogs with obstructive jaundice. NAC increased the concentrations of plasma cyclic 3',5'-guanosine monophosphate (cGMP). It also increased concentrations of serum and hepatic-reduced glutathione, and hepatic adenosine triphosphate (ATP) in cholestatic dogs, and secretion of cGMP from sinusoidal endothelial cells from rats with obstructive jaundice. CONCLUSION: These results suggest that NAC given intravenously effectively improves hepatic circulation and hepatic function in dogs with obstructive jaundice.

Acetylcysteine↗
PubMed2000

Activated protein C reduces the ischemia/reperfusion-induced spinal cord injury in rats by inhibiting neutrophil activation.

OBJECTIVE: To examine whether activated protein C (APC) reduces spinal cord injury in rats by inhibiting neutrophil activation after the transient ischemia. SUMMARY BACKGROUND DATA: Ischemic spinal cord injury is an important pathologic mechanism leading to the paraplegia observed after surgery to repair aortic aneurysms. Activated neutrophils play a pivotal role in the development of ischemia/reperfusion-induced tissue injury. Recently, the authors have reported that APC, a physiologic anticoagulant, prevents lipopolysaccharide-induced pulmonary vascular injury by inhibiting neutrophil activation. These observations strongly suggest that APC reduces ischemia/reperfusion-induced spinal cord injury by inhibiting neutrophil activation. METHODS: In rats, spinal cord ischemia was induced by using a balloon catheter placed into the aorta. After the transient ischemia, survival and motor function were evaluated, and histologic examination of the spinal cord was performed by using both hematoxylin-and-eosin staining and 2,3,5, -triphenyltetrazolium chloride (TTC) staining 24 hours after the ischemia. Tissue levels of myeloperoxidase and cytokines, including tumor necrosis factor-alpha (TNF-alpha) and rat interleukin-8, were measured in six experimental groups: sham-operated, control, APC (100 microg/kg, intravenous), dansyl glutamyl-glycyl-arginyl chloromethyl ketone-treated activated factor X (DEGR-F.Xa), a selective inhibitor of thrombin generation (1 mg/kg, intravenous), nitrogen mustard-induced leukocytopenia, and diisopropyl fluorophosphate-treated APC (DIP-APC), active site-blocked APC (100 microg/kg, intravenous). APC, DEGR-F.Xa, and DIP-APC were administered intravenously 30 minutes before aortic occlusion. Control and leukocytopenic rats received saline instead of other drugs. RESULTS: Pretreatment with APC significantly reduced motor disturbances compared with those in control animals. In contrast, neither DEGR-F.Xa nor DIP-APC had any effect. Microinfarctions, evidenced by the absence of TTC staining and histologic change, were markedly reduced in animals given APC. The increases in the tissue levels of TNF-alpha, rat interleukin-8, and myeloperoxidase in the ischemic part of the spinal cord were significantly reduced in animals that received APC. These levels were not reduced in rats given DEGR-F.Xa or DIP-APC. Leukocytopenia produced effects similar to those of APC. CONCLUSIONS: APC reduced the ischemia/reperfusion-induced spinal cord injury by inhibiting neutrophil activation. The therapeutic mechanisms of APC might depend on its inhibitory effect on the production of TNF-alpha, which is a potent activator of neutrophils. Although the anticoagulant effects of APC might not be related to its ability to inhibit TNF-alpha production, its serine protease activity appears to be essential in the therapeutic mechanism. APC appears to have potential as a therapeutic agent for prevention of spinal cord injury in patients undergoing aortic aneurysm repair.

Animals↗
PubMed2000

Nicotinamide increases biosynthesis of ceramides as well as other stratum corneum lipids to improve the epidermal permeability barrier.

BACKGROUND: Stratum corneum lipids, particularly ceramides, are important components of the epidermal permeability barrier that are decreased in atopic dermatitis and aged skin. OBJECTIVES: We investigated the effects of nicotinamide, one of the B vitamins, on biosynthesis of sphingolipids, including ceramides and other stratum corneum lipids, in cultured normal human keratinocytes, and on the epidermal permeability barrier in vivo. METHODS: The rate of sphingolipid biosynthesis was measured by the incorporation of [14C]-serine into sphingolipids. RESULTS: When the cells were incubated with 1-30 micromol L-1 nicotinamide for 6 days, the rate of ceramide biosynthesis was increased dose-dependently by 4.1-5. 5-fold on the sixth day compared with control. Nicotinamide also increased the synthesis of glucosylceramide (7.4-fold) and sphingomyelin (3.1-fold) in the same concentration range effective for ceramide synthesis. Furthermore, the activity of serine palmitoyltransferase (SPT), the rate-limiting enzyme in sphingolipid synthesis, was increased in nicotinamide-treated cells. Nicotinamide increased the levels of human LCB1 and LCB2 mRNA, both of which encode subunits of SPT. This suggested that the increase in SPT activity was due to an increase in SPT mRNA. Nicotinamide increased not only ceramide synthesis but also free fatty acid (2.3-fold) and cholesterol synthesis (1.5-fold). Topical application of nicotinamide increased ceramide and free fatty acid levels in the stratum corneum, and decreased transepidermal water loss in dry skin. CONCLUSIONS: Nicotinamide improved the permeability barrier by stimulating de novo synthesis of ceramides, with upregulation of SPT and other intercellular lipids.

Acyltransferases↗
PubMed2000

Endosomal localization and receptor dynamics determine tyrosine phosphorylation of hepatocyte growth factor-regulated tyrosine kinase substrate.

Hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) is a prominent substrate for activated tyrosine kinase receptors that has been proposed to play a role in endosomal membrane trafficking. The protein contains a FYVE domain, which specifically binds to the lipid phosphatidylinositol (PI) 3-phosphate (PI 3-P). We show that this interaction is required both for correct localization of the protein to endosomes that only partially coincides with early endosomal autoantigen 1 and for efficient tyrosine phosphorylation of the protein in response to epidermal growth factor stimulation. Treatment with wortmannin reveals that Hrs phosphorylation also requires PI 3-kinase activity, which is necessary to generate the PI 3-P required for localization. We have used both hypertonic media and expression of a dominant-negative form of dynamin (K44A) to inhibit endocytosis; under which conditions, receptor stimulation fails to elicit phosphorylation of Hrs. Our results provide a clear example of the coupling of a signal transduction pathway to endocytosis, from which we propose that activated receptor (or associated factor) must be delivered to the appropriate endocytic compartment in order for Hrs phosphorylation to occur.

Amino Acid Sequence↗
PubMed2000

Upregulation of HGF activator inhibitor type 1 but not type 2 along with regeneration of intestinal mucosa.

Hepatocyte growth factor (HGF) activator inhibitor type 1 (HAI-1) and type 2 (HAI-2) are new Kunitz-type serine protease inhibitors that were recently purified and cloned from the human stomach cancer cell line MKN45 as specific inhibitors against HGF activator. Both proteins contain two Kunitz inhibitor domains and are expressed abundantly throughout the gastrointestinal tract, in addition to the placenta, pancreas, and kidney. In this study, to assess the possible roles of HAI-1 and HAI-2 in the intestinal mucosa, we examined the expression of HAI-1 and HAI-2 during regeneration of the intestinal mucosa. Immunohistochemical studies revealed that HAI-1 but not HAI-2 was detected more strongly in regenerative epithelium than in normal epithelium, although both proteins were detected throughout the human gastrointestinal tract. During the course of acetic acid-induced experimental colitis in an in vivo mouse model, HAI-1 but not HAI-2 was upregulated in the recovery phase, suggesting that HAI-1 but not HAI-2 is associated with the regeneration of damaged colonic mucosa. Upregulation of HAI-1 may serve to downregulate the proliferative response after initial activation of MET receptor by HGF/scatter factor after an injury.

Acetic Acid↗
PubMed2000

Susceptibility to lipopolysaccharide of cholestatic rat liver produced with bile duct ligation: assessments of the mitochondrial glutathione pool and the effects of N-acetylcysteine.

We investigated whether rats with obstructive jaundice produced with bile duct ligation for 2 weeks are more susceptible to the additional stress of lipopolysaccharide (LPS) administration than sham-operated rats and also examined the effects of N-acetylcysteine (NAC) on LPS stimulation in rats with bile duct ligation. The effects of LPS on the mitochondrial glutathione pool and on oxidative stress of polymorphonuclear leukocytes were investigated in cholestatic rats. Serum concentrations of alpha-glutathione S-transferase showed that lipopolysaccharide stimulation caused more severe hepatocellular injury in cholestatic rats than in sham-operated rats. In addition, concentrations of mitochondrial reduced and oxidized glutathione and hepatic adenosine triphosphate showed that LPS stimulation decreased mitochondrial function more in cholestatic rats than in sham-operated rats. Intraperitoneal administration of NAC for 2 weeks significantly improved mitochondrial function and decreased hepatocellular injury. However, the oxidative stress of polymorphonuclear leukocytes that had infiltrated hepatic tissue was increased by NAC. The present results indicate that the cholestatic liver is susceptible to the additional stress of LPS, that NAC suppresses the adverse effects of LPS in cholestatic livers, and that the oxidative stress of polymorphonuclear leukocytes is not significantly involved in mitochondrial dysfunction or hepatocellular injury in this model.

Acetylcysteine↗
PubMed2000

[Indocyanine green (TCG) clearance as a monitor to evaluate right heart function].

Systemic venous return to the heart is disturbed as a result of right heart failure. ICG clearance is known to be influenced by hepatic venous return to the right atrium. Under a hypothesis that right heart function could be evaluated by ICG clearance test, patients with mitral valve disease (Group M, n = 29), aortic valve disease (Group A, n = 16), ischemic heart disease (Group CABG, n = 19) were studied. Preoperative K-ICG (normal range > 0.17) in the Group M was significantly lower than those in the Group A and Group CABG (0.097 +/- 0.037 vs 0.166 +/- 0.032 and 0.171 +/- 0.027, p < 0.05). In the Group M, patients who underwent tricuspid annuloplasty (TAP) had significantly lower K-ICG than the others (0.077 +/- 0.026 vs 0.113 +/- 0.038, p < 0.05). Postoperatively, K-ICG of TAP patients significantly increased (0.092 +/- 0.031, p < 0.05) when compared to their preoperative value. ICG clearance test was useful to quantify the right heart function, especially in the postoperative evaluation.

Female↗
PubMed2000

[Hepatic function after surgical repair of constrictive pericarditis].

We report the results of long-term follow up in 9 patients who underwent pericardiectomy for constrictive pericarditis. In order to test whether if congestive liver dysfunction due to the disease could be reversible or not after the surgical repair, the patients were evaluated by indocyanine green (ICG) clearance test. All the patients improved in NYHA classification after long-term periods following surgical repairs. The percentage of ICG retention at 15 minutes (ICG-R15) improved in most of the patients. However, two patients who had a long history from the onset before surgery became worse in ICG-R15. From the above reports, reversibility of hepatic function might be dependent on the duration of liver congestion before surgical repairs.

Adult↗
PubMed2000

[Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (1998)].

The bacteria isolated from the patients with lower respiratory tract infections were collected by institutions located throughout Japan, since 1981. Ikemoto et al. have been investigating susceptibilities of these isolates to various antibacterial agents and antibiotics, and analyzed some characteristics of the patients and isolates from them each year. Results obtained from these investigations are discussed. In these 18 institutions around the entire Japan, 532 strains of presumably etiological bacteria were isolated mainly from the sputa of 438 patients with lower respiratory tract infections during the period from October in 1998 to September in 1999. MICs of various antibacterial agents and antibiotics were determined against 85 strains of Staphylococcus aureus, 100 strains of Streptococcus pneumoniae, 96 strains of Haemophilus influenzae, 75 strains of Pseudomonas aeruginosa (non-mucoid strains), 6 strains of Pseudomonas aeruginosa (mucoid strains), 38 strains of Moraxella subgenus Branhamella catarrhalis, 26 strains of Klebsiella pneumoniae etc., and the susceptibilities of 517 strains were assessed except for those strains that died during transportation. S. aureus strains for which MICs of oxacillin (MPIPC) were higher than 4 micrograms/ml (methicillin-resistant S. aureus: MRSA) accounted for 60.0%. Vancomycin (VCM) and arbekacin (ABK) showed the most potent activities against MRSA. But one of MRSA showed resistance to ABK with the MIC of 64 micrograms/ml. The sensitive strains of MRSA to VCM have decreased. The frequency of penicillin (PC)-intermediate S. pneumoniae (PISP) + PC-resistant S. pneumoniae (PRSP) have increased in 46.0% for 1998 comparatively from 30.9% of 1997's. But PRSP decreased, and PISP increased into 39.0% of 1998 years from 19.8% of 1997's. Panipenem (PAPM), imipenem (IPM) and faropenem (FRPM) showed the most potent activities against S. pneumoniae with MIC80s of 0.125 microgram/ml or below. Against H. influenzae and M. (B.) catarrhalis, almost all the drugs showed good activities. The sensitive strains of them against ceftazidime (CAZ) decreased in 1997, but those have increased in 1998. Inversely, the susceptibility of them against cefotiam (CTM) had been higher in 1997, but those have been lower in 1998. Tobramycin (TOB) showed the most potent activity against P. aeruginosa (both mucoid and nonmucoid strains). All drugs except ampicillin (ABPC) were active against K. pneumoniae. A quite few of K. pneumoniae showed low susceptibilities. Also, we investigated year to year changes in the characteristics of patients, their respiratory infectious diseases, and the etiology. The examination of age distribution indicated that the proportion of patients with ages over 70 years was 48.6% of all the patients showing a slight increase in every year. About the proportion of diagnosed diseases as follows: Bacterial pneumonia was the most frequent with 40.2%. The ratio of it has increased slightly, and the increased rate was 10% in patients with ages over 70 years compared with the results in 1997. Chronic bronchitis have decreased slightly with 27.6% in 1998. Number of strains isolated from patients before administration of antibiotics were more than those after administration of them in chronic bronchitis, but these were almost same number in bacterial pneumonia. Administration of antibiotics has changed the results of the frequency of isolation of bacterial species. Bacterial isolations before administration of antibiotics were as follows: S. pneumoniae 26.7%, H. influenzae 23.8%, S. aureus 13.3% and M. (B.) catarrhalis 10.8%. The frequencies of S. aureus decreased after antibiotics administration over 15 days, but the frequencies of P. aeruginosa (both mucoid and non-mucoid) was not affected. The frequencies of P. aeruginosa was 45.5% after administration over 15 days. The frequencies of S. pneumoniae decreased upon administration of antibiotics, these were only 4.5% over 15 days. The frequencies of H. (

Anti-Bacterial Agents↗
PubMed2000

Rescue of embryonic lethality in hepatocyte growth factor/scatter factor knockout mice.

While the targeted disruption of a gene is a powerful tool for investigating the physiological functions of that gene, disruption of a gene essential for embryogenesis leads to embryonic death. Rescue of the defect(s) causing embryonic death should promote survival, thus permitting further evaluation of the roles that the gene plays later in the developmental process. Disruption of the gene for mouse hepatocyte growth factor/scatter factor (HGF/SF) leads to middle-stage embryonic lethality because of a defect in placental development. Here we report that a single injection of HGF/SF at embryonic day 9.5 (E9.5) into the amniotic cavity of HGF/SF(-/-) embryos rescued the placental defect and resulted in the survival of the embryos until term. Histological analysis suggested that HGF/SF is also required at the late stage of development for tissue organogenesis. Thus, injection of a secreted factor can be a useful method to rescue the defects causing embryonic lethality.

Amniotic Fluid↗
PubMed2000

[Vascular anastomoses in free jejunal reconstruction to the neck vessels: an experience of consecutive 20 cases without using surgical microscope].

Twenty consecutive cases of pharyngoesophageal cancer who underwent free jejunal reconstruction were reported. The common carotid or external carotid artery was used for a feeder of the free graft. The internal jugular vein were served as a drainage vein. All anastomoses were performed in an end-to-side fashion without using surgical microscopes. Mean carotid artery clamping time was 16 minutes and no neurological complications were noticed postoperatively. Graft failure was occurred in 1 patient. The presenting technique, showing 95% success rate, is recommended as a simple option for vascular anastomosis in free jejunal reconstructive surgery.

Anastomosis, Surgical↗