Search PubMed⌕ Search

Biomedical subjects

Y Fujii

Publications and source records attributed to Y Fujii.

At least 415 records · Page 23Linked to original sources
PubMed1998

Contribution of the disulfide bond of the A subunit to the action of Escherichia coli heat-labile enterotoxin.

Escherichia coli heat-labile enterotoxin (LT) consists of an A subunit and five B subunits. These subunits oligomerize into an assembled holotoxin within the periplasm. Structural analysis of LT has revealed that the A subunit interacts with the B subunit through its carboxy terminus. This indicates that the carboxy-terminal portion of the protein is required for assembly of holotoxin in the periplasm. However, it is not known whether other regions of the A subunit contribute to the assembly. The A subunit constituting the holotoxin contains a disulfide bond between Cys-187 and Cys-199. It has been observed in many proteins that the intramolecular disulfide bond is deeply involved in the function and tertiary structure of the protein. We speculated that the disulfide bond of the A subunit contributes to the assembly in the periplasm, although the bond is not a structural element of the carboxy-terminal portion of the A subunit. We replaced these cysteine residues of the A subunit by oligonucleotide-directed site-specific mutagenesis and analyzed the LTs produced by cells containing the mutant LT genes. The amount of the mutant holotoxin produced was small compared with that of the wild-type strain, indicating that the disulfide bond of the A subunit contributes to the structure which functions as the site of nucleation in the assembly. A reconstitution experiment in vitro supported the notion. Subsequently, we found that the mutant A subunit constituting holotoxin is easily degraded by trypsin and that in cells incubated with mutant LTs, the lag until the intracellular cyclic AMP begins to accumulate is longer than in cells incubated with native LTs. These results might be useful for the analysis of the interaction of LT with target cells at the molecular level.

Amino Acid Sequence↗
PubMed1998

Regulation of nitric oxide production in response to skeletal muscle activation.

Nitric oxide (NO) is synthesized in normal muscle fibers by the neuronal (nNOS) and the endothelial (ecNOS) isoforms of nitric oxide synthase (NOS). NO contributes to the regulation of several processes such as excitation-contraction coupling and mitochondrial respiration. We assessed in this study whether NO production is regulated in response to an acute increase in muscle activation. Three groups of anesthetized, tracheostomized, spontaneously breathing rats were examined after an experimental period of 3 h. Group 1 served as a control (no loading), whereas groups 2 and 3 were exposed to moderate and severe inspiratory resistive loads, respectively, which elicited tracheal pressures of 30 and 70% of maximum, respectively. Ventilatory (diaphragm, intercostal, and transverse abdominis) and limb (gastrocnemius) muscles were excised at the end of the experimental period and examined for NOS activity and NOS protein expression. Neither submaximal nor maximum tracheal pressures were altered after 3 h of resistive loading. Diaphragmatic and intercostal muscle NOS activities declined significantly in response to moderate and severe loading, whereas those of transverse abdominis and gastrocnemius muscles remained unchanged. On the other hand, resistive loading had no significant effect on ventilatory and limb muscle NOS isoform expression. We propose that a contraction-induced decline in muscle NOS activity represents a compensatory mechanism through which muscle contractility and mitochondrial function are protected from the inhibitory influence of NO.

Animals↗
PubMed1998

Beneficial effects of verapamil on intestinal ischemia and reperfusion injury: pretreatment versus postischemic treatment.

We studied the effect of verapamil on intestinal ischemia and reperfusion (I/R) injury. Intestinal ischemia was induced by clamping the superior mesenteric artery for 30 min followed by reperfusion. Magnetic resonance spectroscopy was employed as a marker of the changes in the energy metabolism. Further, histological changes and the changes of water contents were evaluated. Recovery rates of energy metabolism after intestinal I/R were improved by verapamil, administered before and after ischemia, and tissue edema was significantly reduced with verapamil. These findings suggest that verapamil results in an improved recovery of the energy metabolism and cellular preservation, presumably by reducing the intracellular calcium influx.

Animals↗
PubMed1998

Molecular cloning, mapping, and characterization of two novel human genes, ORCTL3 and ORCTL4, bearing homology to organic-cation transporters.

Through a large-scale sequencing of genomic DNA at 3p22-->p21.3, we have isolated two human genes (ORCTL3 alias OCTL1 and ORCTL4 alias OCTL2) encoding novel members of the family of organic-cation transporter molecules. The predicted proteins revealed the highest similarities to recently- isolated organic-cation transporter proteins, rat OCT-1r, rat NLT and mouse NKT. The transcripts of both genes were expressed ubiquitously in various human tissues, but some tissue-specific transcripts were also observed in kidney, testis, or skeletal muscle. The two genes are clustered within a 52-kb region of genomic DNA and ORCTL4 lies about 27 kb telomeric to ORCTL3 in the genomic DNA sequence in a tail-to-head orientation.

Amino Acid Sequence↗
PubMed1998

Significance of bladder neck involvement on progression in superficial bladder cancer.

OBJECTIVES: To determine the significance of bladder neck involvement in predicting disease progression in superficial (stage Ta and T1) transitional cell carcinoma (TCC) of the urinary bladder. PATIENTS AND METHODS: A series of 277 patients with newly diagnosed superficial TCCs of the bladder was reviewed, and disease progression (to T2 or worse) was considered. The significance of several risk factors including bladder neck involvement was assessed in univariate and multivariate analysis. RESULTS: Progression occurred in 28 (10.1%) of 277 patients during a median follow-up period of 7.7 years. Nineteen died of bladder cancer. The following variables were found to be statistically significant at the univariate analysis (p < 0.05): irritative symptoms, urine cytology, tumor stage, involvement of the bladder neck, and tumor grade. Indeed, only involvement of the bladder neck, tumor stage, and grade retained their value as independent factors for progression at multivariate analysis. Patients were divided into three groups according to the number of independent risk factors they had. Groups having none, one, and two or three risk factors included 129, 99, and 49 patients with 5-year progression rates of 0.8, 4.6 and 27.5%, and 15-year rates of 4.0, 20.1 and 42.7%, respectively. CONCLUSION: Involvement of the bladder neck is a significant and independent risk factor for progression of superficial TCCs in addition to the histologic grade and stage. The combination of these three risk factors offers better prediction of progression in an individual patient.

Adolescent↗
PubMed1998

Ultrastructural study of anionic sites in glomerular basement membranes at different perfusion pressures by quick-freezing and deep-etching method.

The ultrastructures of anionic sites in rat glomerular basement membranes (GBM) were studied at different perfusion pressures of 100, 150, 200 or 250 cm H2O by a quick-freezing and deep-etching (QF-DE) method, in addition to conventional fixation methods, using polyethyleneimine (PEI) as a cationic tracer. By the QF-DE method, three-dimensional ultrastructures at each pressure were observed more clearly than those seen on conventional ultrathin sections. When the perfusion pressures were changed from low levels to higher ones, the total thickness of GBM with anionic sites became gradually thinner. Many PEI particles were observed around filaments, not only in the laminae lucidae, but also in the lamina densa. These findings indicated the existence of anionic sites in both laminae lucidae and lamina densa of GBM. The numbers of PEI particles in the lamina rara externa were counted on conventional ultrathin sections for morphometric analyses. The numbers per unit length of GBM were significantly decreased at higher perfusion pressures (200 and 250 cm H2O) than those seen at both normal (150 cm H2O) and lower (100 cm H2O) pressures. It is concluded that the ultrastructures of anionic sites in the GBM may be changed in vivo, depending on the hemodynamics in the glomerular capillary.

Animals↗
PubMed1998

Multivariate analysis of predictors of hematoma enlargement in spontaneous intracerebral hemorrhage.

BACKGROUND AND PURPOSE: We conducted this study to determine, through use of multivariate analyses, the independent predictors of hematoma enlargement occurring after hospital admission in patients with spontaneous intracerebral hemorrhage (i.c.h.). METHODS: We reviewed 627 patients with ICH admitted within 24 hours of onset. The first CT was performed at admission and the second within 24 hours of admission, and a blood sample was taken for laboratory examinations. Univariate and multivariate analyses were performed to assess the relationships between hematoma enlargement and time from onset, consciousness level, CT findings, amount of alcohol consumption, systolic blood pressure at and after admission, clinical outcome, and hematologic parameters. RESULTS: Eighty-eight patients (14.0%) showed enlarged hematomas after admission. Multivariate analyses revealed that the following five factors were independently associated with hematoma enlargement: the time from onset (odds ratio [OR], 0.26 for a 1-SD change; 4.9 hours; P < 0.001); the amount of alcohol consumption (OR, 1.50 for 1 SD; 46.3 g/d; P = 0.002); the sharp of hematoma (OR, 1.40 for 1 SD; 0.45 round; P = 0.006); the presence of consciousness disturbance (OR, 1.38 for 1 SD; 0.50 coma; P = 0.026); and the level of fibrinogen (OR, 0.74 for 1 SD; 87.1 mg/dL; P = 0.042). Hematoma enlargement was an independent factor increasing the mortality rate in the ICH patients (OR, 1.57; P < 0.001). CONCLUSIONS: A particularly high likelihood of hematoma enlargement was observed in patients who (in order of importance) were admitted shortly after onset, who were heavy drinkers; who had an irregularly shaped hematoma, whose consciousness was disturbed, and who had a low level of fibrinogen.

Aged↗
PubMed1998

Contribution of macrophages to pulmonary nitric oxide production in septic shock.

Bacterial lipopolysaccharide (LPS) is known to induce the expression of inducible nitric oxide synthase (iNOS) in the lung and to lead to increased pulmonary nitric oxide (NO) production. The contribution of various pulmonary cells to this phenomenon remains unclear. In this study, we used gadolinium chloride, a blocker of macrophage activation, to assess the role of macrophages in LPS-induced pulmonary NO production. Anesthetized, mechanically ventilated rats were injected with either saline or LPS (Escherichia coli endotoxin) and studied for 5 h. Two other groups of rats were pretreated 24 h earlier with gadolinium chloride. Unlike control rats, rats injected with LPS showed a progressive decline in arterial pressure and a several-fold rise in lung iNOS activity and exhaled NO concentration. Large numbers of alveolar macrophages also expressed iNOS after LPS injection. Gadolinium chloride pretreatment eliminated the rise in lung iNOS activity and protein expression and significantly attenuated the increase in pulmonary exhaled NO product, but it had no effect on arterial pressure. Fewer numbers of alveolar macrophages expressed iNOS protein after gadolinium pretreatment. We conclude that macrophage activation plays a critical role in enhancing NO production in the respiratory system, but it is of less importance in mediating hemodynamic alterations of acute endotoxemia.

Animals↗
PubMed1998

[Anti-dermaptophyte activity of phenolic compounds in "mokusaku-eki"].

"Mokusaku-eki," a kind of pyroligneous acid, is a dark brown color solution obtained from the charcoal burner of such Quercus spp. woods as a by-product. This is used as a folk medicine in water eczema. The n-hexane fraction of this solution contained several phenolic compounds such as 4-ethyl-2-methoxyphenol (3) and 2,6-dimethoxyphenol (4), which could not be found in the fresh woods. Among these compounds, 3 has the highest anti-dermaptophyte activity against Trichophyton mentagrophytes at minimum inhibitory concentration (MIC) 150 micrograms/ml.

Alkaloids↗
PubMed1998

Intrathoracic and extrathoracic sources of exhaled nitric oxide in porcine endotoxemic shock.

OBJECTIVES: Nitric oxide (NO), a highly reactive species produced by the activity of NO synthases (NOS), is normally present in the exhaled air of humans and animals. Exhaled NO concentration increases significantly in humans with sepsis and animals, but neither the source nor NOS isoforms responsible for this rise in pulmonary NO production are known. The main objective of this study is to determine the sites and the mechanisms of enhanced NO production in the exhaled air of endotoxemic pigs. DESIGN: Randomized, controlled, animal study. SETTING: University-based animal research facility. SUBJECTS: Thirteen pathogen-free adult female pigs (22 to 27 kg). INTERVENTIONS: Anesthetized pigs were divided into two groups: control and lipopolysaccharides (LPS) (septic) groups. In both groups, extrathoracic (upper airways, nasal, and paranasal) and intrathoracic (bronchi, bronchioles, and alveoli) compartments were ventilated equally with two separate ventilators connected to two tracheal tubes. The LPS group received slow infusion (over 2 h) of Escherichia coli endotoxin (10 microg/kg/h), whereas saline solution was infused into the control group. Expired air of the two compartments was collected throughout the 2-h observation period. The animals were then killed and the lungs were quickly excised and frozen. MEASUREMENTS: Hemodynamic variables were measured in both groups. NO concentration in the exhaled air of both compartments was measured with a chemiluminescence analyser. Pulmonary NOS activity was evaluated by measuring the conversion of L-[2,3H]-arginine to L-[2,3H]-citrulline, and pulmonary expression of NOS was evaluated by immunoblotting. RESULTS: Baseline NO concentration in both groups was significantly higher in the extrathoracic vs intrathoracic compartment (average of 5.2 vs 3.4 parts per billion). Endotoxin infusion elicited a significant and early (after 45 min) rise in exhaled NO concentration in the extrathoracic compartment. Exhaled NO in the intrathoracic compartment also rose significantly but after 90 min of endotoxin infusion. Measurement of lung NOS activity showed a substantial rise in Ca++/calmodulin-dependent activity in the LPS group with no rise in Ca++/calmodulin-independent activity. Immunoblotting of lung tissue samples indicated the absence of the inducible isoform in both groups of animals. Moreover, LPS injection elicited no significant alterations in the pulmonary expression of the endothelial and the neuronal isoforms. CONCLUSIONS: Both extrathoracic and intrathoracic compartments contribute to the rise in exhaled NO production in experimental septic shock. The rise in exhaled NO production is due to increased activity of constitutive NOS isoforms as a result of increased cofactor availability and/or downregulation of the endogenous inhibitors of NOS.

Animals↗
PubMed1998

Morphological studies of glomeruli in obstructive kidneys by confocal laser scanning microscopy and quick-freezing replica method.

Morphological changes of glomeruli in obstructive kidneys were studied by using confocal laser scanning microscopy (CLSM), and quick-freezing and deep-etching (QF-DE) method. Twenty-one rabbits were divided into three groups, consisting of control, 6-hr bilateral ureteral obstruction (BUO) and 24-hr BUO. In the experimental groups, the attenuation of cell bodies, the lengthening and stretching of major processes, the cystic formation in the cytoplasm and the fusion of foot processes were observed on conventional ultrathin sections. These changes in the 24-hr BUO group were more clearly observed than those in the 6-hr BUO group. By the CLSM, cell bodies and foot processes of podocytes in the experimental groups were more intensely immunostained with anti-alpha-tubulin antibody and phalloidin-FITC. By the QF-DE method, cytoskeletons in the podocyte cell bodies and major processes were composed of numerous intermediate filaments, but distinct changes of actin filaments and microtubules were not observed in the control and experimental groups. Considering the physiological changes in BUO, the mechanical stress appeared to be brought about by hemodynamic factors rather than the change of intratubular pressure, resembling the morphological changes in experimental animals with hyperfiltration and the homeostatic adaptation of podocytes under the BUO condition.

Animals↗
PubMed1998

Neonatal intrathymic splenocyte injection yields prolonged cardiac xenograft survival.

Intrathymic (i.t.) injection of allogenic cells without administration of anti-lymphocyte serum (ALS) in neonatal recipients has induced donor-specific tolerance to subsequent cardiac allografts in rats. This study examines whether similar tactics can be successfully applied to a hamster-to-rat cardiac xenotransplantation model. Lewis neonates on their first day of life underwent i.t., subcutaneous (s.c.), intraperitoneal (i.p.), or intravenous (i.v.) injections of 5 x 10(7) Golden Syrian hamster splenocytes. After six weeks, the rats underwent heterotopic cardiac transplantation of hamster hearts. Cyclophosphamide (CyP) was administered on the day before surgery and postoperatively to suppress antibody-mediated graft rejection. Rats given splenocytes with 80 mg/kg of CyP had the following graft survival times: 8 to 12 days for i.t. injection (mean, 9.4 days); 5 to 7 days for s.c. injection (mean, 6.6 days); 4 to 11 days for i.p. injection (mean, 7.4 days); and 4 to 13 days for i.v. injection (mean, 7.9 days). Only the extension of graft survival produced by i.t. injection was statistically significant in comparison with the rats given only CyP treatment (mean, 7.5 days; P < 0.05). Thus, it appears that i.t. injection of xenogenic splenocytes in neonatal recipients with administration of CyP, but without ALS, can prolong xenograft survival. This biological intervention may be most useful in pediatric xenotransplantation when combined with other immunomodulation techniques.

Animals↗
PubMed1998

High-resolution T2-reversed magnetic resonance imaging on a high magnetic field system. Technical note.

Because of the high signal-to-noise (S/N) ratio, T2-weighted images obtained using high-field magnetic resonance (MR) imaging systems can be expected to provide high anatomical and contrast resolution. Furthermore, the improved structural and contrast resolution of these high S/N T2-weighted images can be processed for optimum perceptual resolution through the application of gray-scale reversal and expansion of the gray-scale window, known as T2-reversed (T2R) imaging. In this study, the authors investigated high-resolution T2R MR imaging performed on a high-field (3-tesla) system for its clinical utility in detecting various physiological and pathological conditions.

Adolescent↗
PubMed1998

[Construction of a scale for college life anxiety and its reliability and validity].

The purpose of this study are to construct the College Life Anxiety Scale for measuring the level of college students' anxiety and to examine its reliability and validity. After collecting items about the anxiety in college life, factor analysis was performed on the data obtained from 2,782 college students. The result, firstly, showed that the College Life Anxiety Scale consisting of 30 items had three factors, which were daily life anxiety, test anxiety and college maladjustment. Secondly, it was indicated that the Scale had both high test-retest reliability and internal consistency (.82 and .84, respectively). It was also suggested that the Scale had high content, clinical, and criterion-related validities. In conclusion, the College Life Anxiety Scale is well able to measure the level of college students' anxiety in their usual life.

Adaptation, Psychological↗
PubMed1998

[Surgical treatment for lung cancer invading thoracic aorta].

We experienced three surgical cases of lung cancer invading thoracic aorta, and discussed some problems in order to improve the surgical outcome. In the first case, the patient had a ruptured descending aortic aneurysm into a tumor of left lung. Following urgent graft replacement of descending aorta, left pneumonectomy was carried out, but the patient died of bone marrow dissemination which was probably caused by aspiration of the tumor cells on cardiopulmonary bypass. In the second case, the patient underwent resection of the left upper lobectomy combined with resections of the left subclavian artery and distal aortic arch, but died of perforation of aortic arch due to vascular injury by cross clamp. In the third case, an operation was successfully performed for lung cancer invading the aortic arch. Left upper lobectomy with associated resection of aortic arch, left subclavian and common carotid arteries was performed. Both arteries were replaced with a Gelseal Graft.

Adenocarcinoma↗
PubMed1998

Anti-emetic efficacy of prophylactic granisetron, droperidol and metoclopramide in the prevention of nausea and vomiting after laparoscopic cholecystectomy: a randomized, double-blind, placebo-controlled trial.

This study evaluates the prophylactic anti-emetic efficacy of granisetron, droperidol and metoclopramide, for the prevention of post-operative nausea and vomiting in female patients undergoing elective laparoscopic cholecystectomy. The patients were randomly assigned to one of four groups (n = 30 for each group): granisetron 3 mg, droperidol 1.25 mg, metoclopramide 10 mg and placebo (saline). These medications were given immediately before the induction of anaesthesia. During the first 24 h after anaesthesia, the incidence of post-operative nausea and vomiting was 13, 30, 33 and 37% after administration of granisetron, droperidol, metoclopramide and placebo, respectively (P < 0.05, overall Fisher's exact probability test). No clinically important adverse effects were observed in either group. Our results suggest that granisetron is a better anti-emetic than droperidol or metoclopramide for the prevention of post-operative nausea and vomiting after laparoscopic cholecystectomy when compared with a placebo.

Adult↗