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Biomedical subjects

K Fujii

Publications and source records attributed to K Fujii.

At least 235 records · Page 13Linked to original sources
PubMed1999

Eicosanoids and membrane properties in arteries of aged spontaneously hypertensive rats.

OBJECTIVE: The arteries of aged spontaneously hypertensive rats (SHR) exhibit spontaneous electrical activity together with membrane depolarization. Vascular eicosanoid production is increased in SHR, which is further accelerated with aging. We tested the hypothesis that eicosanoids are involved in spontaneous electrical activity, membrane depolarization or both in mesenteric arteries of aged SHR. DESIGN AND METHODS: Membrane potentials were recorded with microelectrodes from the mesenteric arteries of aged (24 months and older) SHR, aged Wistar-Kyoto (WKY) rats and adult (6- to 8-month-old) SHR. RESULTS: The membrane potential was less negative in aged SHR (-38.5 +/- 0.9 mV) than in either aged WKY rats or adult SHR (-49.8 +/- 0.5 and -47.2 +/- 0.6 mV, respectively; P < 0.05 for both). Spontaneous electrical activity (5-20 mV, 1-7/min) was present only in arteries of aged SHR. Spontaneous electrical activity was not affected by phentolamine, atropine or tetrodotoxin, but was abolished by indomethacin, a cyclooxygenase inhibitor, and ONO-3708, a thromboxane A2/prostaglandin H2 receptor antagonist. Furthermore, indomethacin and ONO-3708 hyperpolarized the membrane by about 5 mV in aged SHR but not in the other two groups. Spontaneous electrical activity was enhanced by a thromboxane A2 analog and prostaglandin H2, and was abolished by a Ca2+ antagonist, nicardipine, and Ca(2+)-free solution. CONCLUSIONS: These findings suggest that cyclooxygenase-dependent eicosanoids contribute importantly to both spontaneous electrical activity and membrane depolarization, presumably through activation of the thromboxane A2/prostaglandin H2 receptor, in mesenteric arteries of aged SHR, and that spontaneous electrical activity is mediated by a Ca2+ influx through voltage-dependent Ca2+ channels.

Aging↗
PubMed1999

Association of head trauma with cervical spine injury, spinal cord injury, or both.

BACKGROUND: Links between cervical spine and/or spinal cord injuries and head trauma have not been reported in detail. METHODS: 188 patients with cervical spine and/or spinal cord injury were divided into two groups, i.e., with upper cervical and mid-lower cervical injury, and compared for head injury. RESULTS: Associated head trauma was investigated in 188 patients with cervical spine and/or spinal cord injuries; 35% had moderate or severe injuries. Brain damage was more frequently observed in patients with upper cervical injury than in those with mid to lower cervical injury. Those patients with upper cervical injury appeared to have an elevated risk of suffering skull base fractures, traumatic subarachnoid hemorrhage, and contusional hemotoma. CONCLUSIONS: Approximately one third of patients with cervical spine and/or spinal cord injuries had moderate or severe head injuries. Brain damage was more frequently associated with upper cervical injury. Those patients with upper cervical injury are at greater risk of suffering from skull base fractures and severe intracranial hematomas than those with mid to lower cervical injury.

Adolescent↗
PubMed1999

Gamma-irradiation deregulates cell cycle control and apoptosis in nevoid basal cell carcinoma syndrome-derived cells.

The nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by nevi, palmar and plantar pits, falx calcification, vertebrate anomalies and basal cell carcinomas. It is well known in NBCCS that gamma-irradiation to the skin induces basal cell carcinomas or causes an enlargement of the tumor size, although the details of the mechanism remain unknown. We have established lymphoblastoid cell lines from three NBCCS patients, and we present here the first evidence of abnormal cell cycle and apoptosis regulations. A novel mutation (single nucleotide deletion) in the coding region of the human patched gene, PTCH, was identified in two sibling patients, but no apparent abnormalities were detected in the gene of the remaining patient. Nevertheless, the three established cell lines showed similar features in the following analyses. Flow cytometric analyses revealed that the NBCCS-derived cells were accumulated in the G2M phase after gamma-irradiation, whereas normal cells showed cell cycle arrest both in the G0G1 and G2M phases. The fraction of apoptotic cells after gamma-irradiation was smaller in the NBCCS cells. The level of p27 expression markedly decreased after gamma-irradiation in the NBCCS cells, although the effects of the irradiation on the expression profiles for p53, p21 and Rb did not differ in normal and NBCCS cells. These findings may provide a clue to the molecular mechanisms of tumorigenesis in NBCCS.

Adolescent↗
PubMed1999

Chemopreventive effect of N-(2-cyclohexyloxy-4-nitrophenyl)methane sulfonamide (NS-398), a selective cyclooxygenase-2 inhibitor, in rat colon carcinogenesis induced by azoxymethane.

Non-steroidal anti-inflammatory drugs (NSAIDs) such as sulindac and indomethacin inhibit colon carcinogenesis, and selective cyclooxygenase (COX)-2 inhibitors are considered to be potential chemopreventive agents without the side effects of usual NSAIDs. We reported that NS-398, N-(2-cyclohexyloxy-4-nitrophenyl)methane sulfonamide, suppressed the formation of preneoplastic lesions, aberrant crypt foci (ACF), induced by azoxymethane (AOM) in a short-term assay of rat colon carcinogenesis. In this study, we examined the effects of long-term NS-398 administration on rat colon carcinogenesis. After three AOM treatments at weekly intervals, a dose of 10 mg/kg of NS-398 in 5% Arabic gum solution was administered by gavage three times per week in group 2 until the termination of the experiment. Rats in group 1 were fed in a basal diet and given 5% Arabic gum solution alone after AOM treatment. At 40 weeks after the first AOM treatment, all rats were killed and the whole intestines including colon were examined. While the incidences of whole intestinal and colon neoplasms in group 1 were 84.6% and 80.8%, respectively, those in group 2 (given NS-398) were 51.9% and 44.4% respectively (P=0.0177 and P=0.0103 by Fisher's exact test, respectively). The multiplicities in group 2 (0.67+/-0.78 and 0.48+/-0.58) were also decreased significantly compared with those (1.39+/-1.10 and 1.08+/-0.74) in group 1 (P<0.01 by Welch's method and P<0.002 by Student's t test, respectively). In immunohistochemistry for proliferative cell nuclear antigen (PCNA), the PCNA-stained cell index (7.40+/-0.5) in group 2 was significantly decreased from that in group 1 (14.03+/-0.82) (P<0.001 by Welch's method). The results suggest that NS-398, a selective COX inhibitor, has a chemopreventive activity against colon carcinogenesis without side-effects such as gastric ulceration.

Animals↗
PubMed1999

A fluorogenic allele-specific amplification method for DNA-based screening for inherited metabolic disorders.

Rapidly growing mutation databases for various inherited metabolic diseases raise the possibility of neonatal screening by DNA-based diagnosis. It is therefore important to develop a simple DNA diagnostic method which is suitable for processing a large number of samples. We have devised an allele-specific amplification (ASA) method with a fluorogenic probe (TaqMan probe) to detect point mutations. A pairwise PCR amplification with two sets of allele-specific primers was performed in the presence of the TaqMan probe with real-time fluorescence monitoring on an ABI PRISM 7700 sequence detector. The difference in the amplification efficiency between two PCR reactions was determined by "threshold" cycles to differentiate mutant and normal alleles. The method, TaqMan-ASA, does not require post-PCR processing, thus obviating potential PCR contamination. Since the entire procedure can be carried out in a 96-well microtiter plate format, it is easy to automate. We successfully applied TaqMan-ASA to detect a common g727t mutation in Japanese patients with glycogen storage disease type Ia and a prevalent a985g mutation in Caucasian patients with medium-chain acyl-CoA dehydrogenase deficiency.

Alleles↗
PubMed1999

In vitro anti-Helicobacter pylori activities of new rifamycin derivatives, KRM-1648 and KRM-1657.

The new rifamycin derivatives KRM-1657 and KRM-1648 were evaluated for their in vitro antimicrobial activities against 44 strains of Helicobacter pylori. Although the drugs were not very active against other gram-negative bacteria, the MICs at which 90% of isolates are inhibited for these drugs were lower (0.002 and 0.008 microgram/ml, respectively) than those of amoxicillin and rifampin for H. pylori. Time-kill studies revealed that the bactericidal activities of these agents were due to cell lysis. The results presented here indicate that these new rifamycin derivatives may be useful for the eradication of H. pylori infections.

Anti-Bacterial Agents↗
PubMed1999

Thermus aquaticus ATCC 33923 amylomaltase gene cloning and expression and enzyme characterization: production of cycloamylose.

The amylomaltase gene of the thermophilic bacterium Thermus aquaticus ATCC 33923 was cloned and sequenced. The open reading frame of this gene consisted of 1,503 nucleotides and encoded a polypeptide that was 500 amino acids long and had a calculated molecular mass of 57,221 Da. The deduced amino acid sequence of the amylomaltase exhibited a high level of homology with the amino acid sequence of potato disproportionating enzyme (D-enzyme) (41%) but a low level of homology with the amino acid sequence of the Escherichia coli amylomaltase (19%). The amylomaltase gene was overexpressed in E. coli, and the enzyme was purified. This enzyme exhibited maximum activity at 75 degrees C in a 10-min reaction with maltotriose and was stable at temperatures up to 85 degrees C. When the enzyme acted on amylose, it catalyzed an intramolecular transglycosylation (cyclization) reaction which produced cyclic alpha-1,4-glucan (cycloamylose), like potato D-enzyme. The yield of cycloamylose produced from synthetic amylose with an average molecular mass of 110 kDa was 84%. However, the minimum degree of polymerization (DP) of the cycloamylose produced by T. aquaticus enzyme was 22, whereas the minimum DP of the cycloamylose produced by potato D-enzyme was 17. The T. aquaticus enzyme also catalyzed intermolecular transglycosylation of maltooligosaccharides. A detailed analysis of the activity of T. aquaticus ATCC 33923 amylomaltase with maltooligosaccharides indicated that the catalytic properties of this enzyme differ from those of E. coli amylomaltase and the plant D-enzyme.

Amylose↗
PubMed1999

A surgical treatment of infected pancreatic necrosis: retroperitoneal laparotomy.

BACKGROUND/AIMS: Due to the anatomical location of the pancreas, sufficient drainage of a pancreatic necrosis by laparotomy may be unsatisfactory. METHODS: CT and helical CT have provided extremely useful information on the surgical treatment of necrotic pancreatitis. The retroperitoneal approach (RPA) allows direct and complete removal of necrotic tissues. RESULTS: RPA was used to treat 8 patients with infected pancreatic necrosis. Excision of necrotic tissues was effective and could minimize the complications often associated with laparotomy such as bleeding and intestinal injuries. CONCLUSION: By CT and helical CT, three-dimensional images of pancreatic necrosis are obtained. These investigations have greatly facilitated RPA, which has advantages over laparotomy in the treatment of infected pancreatic necrosis.

Adult↗
PubMed1999

Angiotensin II type 1 receptor antagonist downregulates nonmuscle myosin heavy chains in spontaneously hypertensive rat aorta.

The aim of this study was to clarify the differences between the angiotensin II type 1 (AT1) receptor antagonist and the angiotensin-converting enzyme (ACE) inhibitor on smooth muscle and nonmuscle myosin heavy chain isoforms in aortic smooth muscle cells of Wistar-Kyoto rats and spontaneously hypertensive rats. All 4 myosin heavy chain isoforms are heterogeneously expressed in the smooth muscle cells of the aortic tunica media in 20-week-old rats, and the contractile-type myosin heavy chains are highly expressed in smooth muscle cells of the aortic tunica media compared with the synthetic-type myosin heavy chains. Both the AT1 receptor antagonist and the ACE inhibitor had the same effects on hemodynamics, smooth muscle cell hypertrophy and proliferation, fibrosis, and vascular remodeling in spontaneously hypertensive rats. However, the AT1 receptor antagonist had a more potent effect on the downregulation of the synthetic-type myosin heavy chains than the ACE inhibitor in spontaneously hypertensive rat aortic tunica media. In contrast, these effects of the AT1 receptor antagonist and the ACE inhibitor on hemodynamics, morphology, fibrosis, and expression of myosin heavy chain isoforms in smooth muscle cells of the aortic tunica media were not observed in Wistar-Kyoto rats. Thus, within 6 weeks, the AT1 receptor antagonist might modulate the cellular composition of myosin heavy chain isoforms in smooth muscle cells more efficiently than the ACE inhibitor, without morphological changes in the spontaneously hypertensive rat aorta.

Angiotensin Receptor Antagonists↗
PubMed1999

Impaired isoproterenol-induced hyperpolarization in isolated mesenteric arteries of aged rats.

Stimulation of vascular beta-adrenoceptors leads to membrane hyperpolarization, presumably via the beta-adrenoceptor/G(s) protein/adenylate cyclase signaling cascade; the ionic mechanisms of this phenomenon remain unclear. beta-Adrenoceptor-mediated vascular relaxation is impaired with aging; however, little is known concerning whether beta-adrenoceptor-mediated hyperpolarization is altered with aging. We sought to determine the ionic mechanisms of isoproterenol-induced hyperpolarization in the rat mesenteric resistance artery, as well as the age-related changes in isoproterenol-induced hyperpolarization and their underlying mechanisms. Isoproterenol-induced hyperpolarization was inhibited by high-K(+) solution and glibenclamide (10(-6) mol/L), an inhibitor of ATP-sensitive K(+) channels (K(ATP)), but not by apamin, iberiotoxin, or charybdotoxin, inhibitors of Ca(2+)-activated K(+) channels. Isoproterenol-induced hyperpolarization was markedly less in aged rats (>/=24 months) than in adults rats (12 to 20 weeks) (3x10(-6) mol/L; -3.1 versus -9.9 mV; P<0.001; n=8 to 9). Cholera toxin (10(-9) g/mL), an activator of G(s), evoked hyperpolarization only in adult rats. Hyperpolarization to forskolin, a direct activator of adenylate cyclase, was also reduced to some extent in aged rats (10(-5) mol/L; -8.8 versus -13 mV; P<0.05; n=6), whereas hyperpolarization to levcromakalim, a K(ATP) opener, was comparable in both groups. These findings suggest that isoproterenol elicits hyperpolarization via an opening of K(ATP) in the rat resistance artery and that isoproterenol-induced hyperpolarization is attenuated in aged rats mainly because of a defective coupling of beta-adrenoceptors to adenylate cyclase and partly because of a defect at the level of adenylate cyclase, but not because of an alteration of K(ATP) per se.

Adenylyl Cyclases↗
PubMed1999

Pharmacogenetic analysis of the effect of angiotensin-converting enzyme inhibitor on restenosis after percutaneous transluminal coronary angioplasty.

Angiotensin-converting enzyme (ACE) inhibitors are reported to prevent neointimal formation after balloon injury in animal models, but in most prospective studies in humans, ACE inhibitors failed to prevent restenosis after percutaneous transluminal coronary angioplasty (PTCA). The ACE genotype assigned by an insertion/deletion (I/D) polymorphism is known to affect the potency of ACE inhibitors in several renal diseases. The authors attempted to clarify whether the effect of ACE inhibitors on restenosis might be modified by the ACE genotype. A total of 126 patients was randomly and prospectively assigned to the control group and the imidapril group. In the imidapril group, patients received 5 mg imidapril daily, starting 1 day before PTCA and continuing for 3 to 6 months. Forty-six control (65 vessels) and 32 imidapril patients (43 vessels) completed the study. The minimal lumen diameter before and after the procedure did not differ significantly among the groups with the three genotypes (II, ID, and DD) in both the control and imidapril groups. Late luminal loss during the follow-up period was not related to the ACE genotype in the control group but was significantly related in the imidapril group (II, 0.63+/- 0.19 mm; ID + DD, 1.12+/-0.14 mm, p<0.05). Furthermore, in the II genotype, imidapril significantly reduced late loss and restenosis rate as defined by most of the frequently used definitions. In conclusion the ACE I/D polymorphism may influence the effect of ACE inhibitors in preventing restenosis after PTCA.

Aged↗
PubMed1999

Reversal of hypopigmentation in phenylketonuria mice by adenovirus-mediated gene transfer.

Phenylketonuria (PKU) is caused by deficiency of phenylalanine hydroxylase (PAH) in the liver. Patients with PKU show increased L-phenylalanine in blood, which leads to mental retardation and hypopigmentation of skin and hair. As a step toward gene therapy for PKU, we constructed a replication-defective, E1/E3-deleted recombinant adenovirus harboring human PAH cDNA under the control of a potent CAG promoter. When a solution containing 1.2 x 10(9) plaque-forming units of the recombinant adenovirus was infused into tail veins of PKU model mice (Pah(enu2)), predominant expression of PAH activity was observed in the liver. The gene transfer normalized the serum phenylalanine level within 24 h. However, it also provoked a profound host immune response against the recombinant virus; as a consequence, the biochemical changes lasted for only 10 d and rechallenge with the virus failed to reduce the serum phenylalanine concentration. Administration of an immunosuppressant, FK506, to mice successfully blocked the host immune response, prolonged the duration of gene expression to more than 35 d, and allowed repeated gene delivery. We noted a change in coat pigmentation from grayish to black after gene delivery. The current study is the first to demonstrate the reversal of hypopigmentation, one of the major clinical phenotypes of PKU in mice as well as in humans, by adenovirus-mediated gene transfer, suggesting the feasibility of gene therapy for PKU.

Adenoviridae↗
PubMed1999

Protamine induces elevation of cytosolic free Ca2+ in cultured porcine aortic endothelial cells.

To test the hypothesis that protamine influences calcium movement in endothelial cells, we measured the concentration of intracellular free calcium ([Ca2+]i) in cultured porcine aortic endothelial (PAE) cells in Krebs solution (2.5mM Ca2+, pH 7.4) at 37 degrees C, by fura-2 fluorimetry. The basal [Ca2+]i of PAE cells was 113+/-18 nM (n=6). Protamine increased [Ca2+]i in a concentration-dependent manner (EC50, the concentration having 50% of the maximum effect, 1.4+/-0.3 microg mL(-1), n=6). The response of PAE cells to 100 microg mL(-1) protamine (330+/-80 nM, n=6) was blocked by a Ca2+ chelator, 5 mM glycoletherdiaminetetraacetic acid (EGTA; 131+/-16 nM, n=6), and by a non-selective Ca2+ channel blocker, 3 mM Co2+ (134+/-14 nM, n=6). These results suggest that Ca2+ influx through cell-membrane Ca2+ channels is mainly responsible for the protamine-induced Ca2+ elevation.

Animals↗
PubMed1999

Effects of salt-loading on membrane potentials in mesenteric arteries of spontaneously hypertensive rats.

Although salt intake and blood pressure are correlated, with hypertensives tending to exhibit higher blood pressure sensitivity to salt than normotensives, the precise mechanisms underlying this relationship remain unclear. This study aimed to determine whether salt-loading affects arterial membrane properties of spontaneously hypertensive rats (SHR). SHR and age-matched Wistar Kyoto rats (WKY) received either an 8% high salt diet or standard rat chow from 6 to 16 wk of age. Systolic blood pressure was significantly higher in salt-loaded SHR than in control SHR (267+/-7 vs. 235 +/- 5 mmHg, p < 0.05). The membrane potential of isolated conduit and resistance arteries of the superior mesenteric vascular bed, measured with microelectrodes, was less negative in salt-loaded SHR than in control SHR or salt-loaded WKY (conduit arteries, -39.9 +/- 0.3 vs. -44.5 +/- 0.4 or -47.4 +/- 0.4 mV, respectively, p < 0.05 for each; resistance arteries, -55.5 +/- 0.5 vs. -62.5 +/- 0.5 or -67.0 +/- 0.5 mV, respectively, p < 0.05 for each). Furthermore, conduit arteries of salt-loaded SHR exhibited spontaneous electrical activity (4-13 mV, 1-3/min), which was sensitive to ONO-3708, a thromboxane A2/prostaglandin H2 receptor antagonist. These findings suggest that salt-loading in SHR leads to a membrane depolarization in both conduit and resistance arteries, as well as to spontaneous electrical activity, presumably mediated by eicosanoids, in conduit arteries. These alterations in membrane properties might contribute to the exacerbation of hypertension and/or the target organ damage after salt loading in SHR.

Animals↗
PubMed1999

Quantitative changes of lung tissue components during perinatal period in rats.

Quantitative changes of lung tissue components (air spaces lined by PAS-positive and PAS-negative epithelium, blood vessels and interstitium) were investigated in developing rats from fetal day 18 through neonatal day 1. The volume of the left lung increased significantly from fetal day 18 through neonatal day 1. The percentage and volume of the air spaces increased strikingly between fetal days 20 and 21. However, the percentage of the air spaces lined by PAS-positive epithelium decreased significantly from fetal days 20 to 21, and that of the spaces lined by PAS-negative epithelium increased between the two days. The proliferating cell nuclear antigen (PCNA)-positive cells were rich in the interstitium and epithelium of the air spaces on fetal days 18 and 19. The percentage of the interstitium decreased significantly from fetal day 18 through neonatal day 1, showing remarkable decrease between fetal days 20 and 21. From fetal day 20 onward, the PCNA-positive cells decreased in number and located in the epithelium of the conducting air ways and interstitium. Based upon these findings, the present study suggests that the period from fetal days 20 to 21 is a critical time for the development of fetal lung: the period before fetal day 20 is that for proliferation and the period after fetal day 21, functional differentiation of the lung.

Animals↗
PubMed1999

Diurnal variations of blood pressure in dogs.

Using the telemetry system, we measured the blood pressure (BP) invasively in seven adult mongrels while unanesthetized and unbound. Post-operative BP after implanting the telemetry BP transmitter showed temporarily high values due to the invasive nature of the surgery. It was, however, observed that BP gradually decreased thereafter, and showed settled trends from the eighth day post-operatively. When we took the average of the systolic, mean and diastolic BP at hourly intervals for each of the dogs once their BP had settled, a twin peak diurnal variation (at 8:00 and 19:00) was observed. Moreover, significantly high values (p < 0.05) were identified in active state compared with when sleeping or at rest. The 24 hr BP measured by the telemetry system in seven normal dogs resulted in the following values: systolic 123.4 +/- 7.9 mmHg, mean 91.1 +/- 5.6 mmHg, and diastolic 74.5 +/- 4.9 mmHg.

Animals↗
PubMed1999

Selection of antigenic variants of the S glycoprotein of feline infectious peritonitis virus and analysis of antigenic sites involved in neutralization.

The type II feline infectious peritonitis virus (FIPV) epitopes for neutralizing and enhancing antibodies are present on large spike glycoprotein (S) protein. In this study, we established monoclonal antibody-resistant mutant viruses resistant to three different monoclonal antibodies with neutralizing activity in Felis catus whole fetus cells and enhancing activity in feline macrophages, recognizing distinct epitopes on type II FIPV S protein. By comparing the nucleotide sequences of these mutant viruses with that of wild-type virus, we attempted to identify the neutralizing epitopes. The mutations were localized in the region of amino acid residues from 480 to 649 from the N terminal of the S protein.

Amino Acid Sequence↗