Search PubMed⌕ Search

Biomedical subjects

T Yamaguchi

Publications and source records attributed to T Yamaguchi.

At least 487 records · Page 27Linked to original sources
PubMed1999

Regional lymph node metastasis as a predictor of peritoneal carcinomatosis in patients with Borrmann type IV gastric carcinoma.

OBJECTIVE: Postoperative survival of patients with Borrmann type IV gastric carcinoma is significantly worse than that in patients with other Borrmann types of gastric carcinomas. The most common pattern of recurrence in patients with Borrmann type IV gastric carcinoma is peritoneal metastasis. We examined the predictors of developing peritoneal metastasis. METHODS: We retrospectively analyzed the relationship between peritoneal metastasis and Borrmann type IV gastric carcinoma. We also examined the dependence of the peritoneal metastasis on clinicopathological findings. RESULTS: Borrmann type IV was an independent prognostic factor of survival by multivariate analysis, and regional lymph node metastasis was an independent predictor of peritoneal metastasis in patients with Borrmann type IV gastric carcinoma. CONCLUSION: Because type of lymph node dissection was not associated with developing peritoneal metastasis, early detection of cancer without lymph node metastasis may be the only means of improving survival in patients with Borrmann type IV gastric cancer.

Carcinoma↗
PubMed1999

Carbon monoxide overproduced by heme oxygenase-1 causes a reduction of vascular resistance in perfused rat liver.

This study aimed to examine whether livers overexpressing heme oxygenase (HO)-1 could alter the vascular resistance through the vasorelaxing action of carbon monoxide (CO). The relationship among HO-1 expression, CO generation, and the vascular resistance was assessed in perfused rat livers pretreated with hemin, an inducer of HO-1. At 18 h after the hemin treatment, livers displayed marked increases in HO-1 expression in hepatocytes and venous CO flux and a reduction of the basal resistance. The reduction of the resistance in hemin-treated livers was canceled by administration of oxyhemoglobin, a reagent trapping both CO and nitric oxide (NO), but not by methemoglobin, which captures NO but not CO. Liposome-encapsulated oxyhemoglobin, which cannot access the space of Disse, did not cause vasoconstriction. Furthermore, these livers became less sensitive to endothelin-1, a vasoconstrictive peptide, than the untreated controls through mechanisms involving CO. On the other hand, at 12 or 24 h after the treatment when the HO-1 induction was not accompanied by CO overproduction, neither a decrease in the basal resistance nor vascular hyporeactivity to endothelin-1 was observed. These results suggest that CO overproduced in the extrasinusoidal compartment is a determinant of the HO-1-mediated vasorelaxation in the liver.

Animals↗
PubMed1999

Bilirubin as an anti-oxidant for surgical stress: a preliminary report of bilirubin oxidative metabolites.

BACKGROUND: Bilirubin has been recognized as an anti-oxidant. The purpose of this study was to examine whether bilirubin would act as an antioxidant for surgical stress in humans. MATERIALS AND METHODS: Serum bilirubin and urinary bilirubin oxidative metabolites (BOM) were measured in 96 patients who underwent surgery. The antioxidant activity of bilirubin was assessed using BOM measured by enzyme-linked immunosorbent assay with an anti-bilirubin monoclonal antibody. RESULTS: Serum bilirubin levels increased after surgery in all 96 patients (p < 0.01), but did not correlate with operation time or blood loss (p = 0.53 and p = 0.28, respectively). BOM increased only in patients with major surgeries (p = 0.048). Significant correlations between BOM and operation time and blood loss were found (p < 0.01). CONCLUSIONS: Bilirubin appears to act as an antioxidant for invasive surgery in humans. Urinary BOM could be a reliable marker for the degree of surgical stress.

Adolescent↗
PubMed1999

Clara cell protein-positive epithelial cells are reduced in small airways of asthmatics.

Clara cell 10 kilodalton protein (CC10), the predominant product from nonciliated cells in the epithelial lining of bronchioles (Clara cells), has been shown to have immunomodulatory and anti-inflammatory activity, and may play roles in controlling inflammation in the airway. This study was designed to examine immunohistochemical expression of CC10 in epithelial cells in small airways (perimeter < 6 mm) of asthmatic and control nonsmokers who underwent lung resection because of peripheral lung carcinoma and to compare CC10-positive epithelial cell proportions with numbers of inflammatory cells in small airways of asthmatics. Significantly decreased proportions of CC10-positive epithelial cells and significantly increased numbers of T cells, activated eosinophils, and mast cells in small airways of asthmatics were found compared with those of control subjects. CC10-positive epithelial cell proportions inversely correlated with numbers of T cells and mast cells in small airways of asthmatics. Decreases of CC10-producing cells may give an accelerating cause for further aggravation of inflammatory responses in chronic asthma.

Asthma↗
PubMed1999

Protective effects of heme oxygenase-1 against oxidant-induced injury in the cultured human tracheal epithelium.

To examine whether increases in heme oxygenase (HO)-1 activity have protective effects on the oxidant-induced injury of airway epithelial cells, human tracheal epithelial cells were cultured on a porous filter membrane, and electrical conductance (G) and mannitol flux across epithelial membrane were measured with Ussing's chamber methods and D-[(3)H]mannitol, respectively. Hydrogen peroxide (H(2)O(2); 1 mM) increased G with time from the baseline value of 6.0 +/- 0.6 to 17.8 +/- 0.9 mS/cm(2) at 6 h after administration (P < 0.001). Likewise, H(2)O(2) significantly increased mannitol flux through the cultured epithelium (P < 0.01). Pretreatment of cultured epithelial cells with hemin (10 microM; 8 h) or interleukin (IL)-1beta (10 ng/ml; 16 h) completely inhibited increases in G and mannitol flux induced by H(2)O(2). Tin protoporphyrin IX (50 micrometer) and zinc protoporphyrin IX (10 microM), inhibitors of HO-1, reduced hemin-induced and IL-1beta-induced inhibitory effects. Hemin treatment increased HO-1 messenger RNA expression, HO-1 protein production, and HO activity and bilirubin content as well as ferritin content in the cultured epithelial cells. Pretreatment with hemin and desferoxamine, which, like ferritin, can bind iron, inhibited H(2)O(2)-induced increases in G and mannitol permeability. Although exogenous bilirubin mimicked hemin-induced inhibitory effects, exogenous apoferritin failed to inhibit H(2)O(2)-induced effects on G and mannitol permeability. These findings suggest that HO-1 induction provides protection against H(2)O(2)-induced injury of the cultured human airway epithelial cells in part via the HO-bilirubin pathway.

Adult↗
PubMed1999

Coronary flow velocity immediately after reperfusion reflects myocardial microcirculation in canine models of acute myocardial infarction.

Recent reports indicate that the coronary microcirculation is sometimes injured, despite successful reperfusion in acute myocardial infarction (AMI). However, it is difficult to evaluate the coronary microcirculation immediately after reperfusion by using only angiography. The purpose of this study was to examine the relationship between the pattern of coronary blood flow velocity and myocardial microcirculatory injury immediately after reperfusion in AMI. The authors recorded the left circumflex coronary flow velocity by using the Doppler guide wire method 10 minutes after reperfusion in a canine model of AMI. In addition, myocardial contrast echocardiography was performed with the injection of contrast medium into the left circumflex coronary artery before clamping of the coronary artery and 15 minutes after release of the clamp. From these images, the ratio of the normalized gray-level postreperfusion to preclamping in the contrast-enhanced area was determined. It was compared with coronary flow velocity variables. In the 10 dogs with a diastolic-to-systolic velocity ratio (DSVR) < 4.0, this velocity ratio 10 minutes after reperfusion correlated positively (r = 0.75, p < 0.01) with the normalized gray-level ratio. However, the remaining three dogs with a DSVR > or = 4.0 markedly deviated from this pattern. Coronary flow velocities in the three dogs were characterized by a greater decrease in systolic flow velocity and occurrence of early systolic retrograde flow. Myocardial contrast echocardiographic images in these three dogs demonstrated a lower normalized gray-level ratio. In conclusion, the coronary flow velocity pattern immediately after reperfusion may reflect myocardial microcirculatory injury.

Albumins↗
PubMed1999

Inhibitory effects of H2-receptor antagonists on platelet function in vitro.

To evaluate in vitro inhibitory effects of four types of histamine H2-receptor antagonist (H2-receptor antagonists), famotidine, roxatidine, cimetidine and ranitidine, on platelet function, we examined aggregating potency and P-selectin levels with agonist-induced aggregation. Ranitidine and cimetidine inhibited, in concentration of 0.35 mM, the secondary aggregation induced by 5 microM adenosine diphosphate (ADP), the aggregation induced by 1 microg/mL collagen and 3 microM arachidonic acid. All of H2-receptor antagonists inhibited, in concentration of 1.4 mM, the aggregation induced by ADP, collagen and arachidonic acid. Ranitidine and cimetidine reduced markedly, in same concentration, P-selectin levels after induction of aggregation by 5 microm ADP, 1 microg/mL collagen and 3 microM arachidonic acid. When classified by the strength of inhibitory action, ranitidine and cimetidine were strong, followed by famotidine and roxatidine. It is considered that inhibitory effects of H2-receptor antagonists on platelet function are weaker than those of acetylsalicylic acid (ASA), since ASA inhibited platelet aggregation in concentration of 100 microM. No relationship was observed between inhibitory effects of H2-receptor antagonists on platelet aggregation induced by above agonists and the presence or absence of imidazole ring in the chemical structure.

Adenosine Diphosphate↗
PubMed1999

Assessment of benzydamine N-oxidation mediated by flavin-containing monooxygenase in different regions of rat brain and liver using microdialysis.

N-Oxidation of benzydamine (BZY) mediated by flavin-containing monooxygenase (FMO) was evaluated by microdialysis in vivo in different regions of rat brain and liver. The probe was implanted into local regions of the brain, such as the olfactory bulb, cerebral cortex, corpus striatum, hippocampus and cerebellum, or the hepatic lobe. By perfusing BZY via the probe, BZY N-oxide was identified in the dialysate. The estimated concentrations of BZY N-oxide in extracellular fluid were almost the same as those in the olfactory bulb, hippocampus and cerebral cortex, half the concentration in the hepatic lobe; however, the concentration in the corpus striatum was lower and that in the cerebellum was higher than in the other regions. These results demonstrate that the extracellular concentration of BZY N-oxide formed in vivo was unexpectedly high in every brain region.

Animals↗
PubMed1999

Release characteristics of endogenous constituents by exposure of small intestine to modified beta-cyclodextrins.

The aim of the present research is to characterize the leakage of intestinal constituents induced by beta-cyclodextrin (beta-CyD) derivatives using an in situ perfusion and an in vitro everted sac. The efficacy of 6-O-alpha-D-glucosyl (G1)- and 6-O-alpha-D-maltosyl (G2)-beta-CyDs as oral carriers was also compared with that of 2-hydroxypropyl-(HP1; average molar degree of substitution, 0.9) and 2,6-di-O-methyl (DM)-beta-CyDs. In the in situ studies, phenol red (PR) penetration and the release profiles of intestinal constituents for G2-beta-CyD were fairly close to those for HP1-beta-CyD. However, the ability of G2-beta-CyD to include cholesterol was greater than that of HP1-beta-CyD. To characterize the release of intestinal constituents induced by modified beta-CyDs, the capability of including cholesterol was held constant between DM- and branched beta-CyDs. The everted sac study showed that the amount of DM-beta-CyD transferred to the serosal side was not significantly different from the branched beta-CyDs. On the serosal side, the amount of cholesterols released was approximately 3 times higher for DM-beta-CyD than for the branched beta-CyDs at 60 min. The cumulative amounts of cholesterols for DM-beta-CyD increased approximately 6 times at 60 min compared with at 30 min, predominating over the leakage (average 2.6-fold) on the mucosal side. In contrast, the exposure of the branched beta-CyDs resulted in an insignificant increase over the period of this experiment. The present study suggests that permeable beta-CyD derivatives play an important role in the leakage of intestinal components. G2-beta-CyD is preferably recommended as a drug solubilizer in oral formulations as well as HP1-beta-CyD, based on the lower release of intestinal constituents.

Administration, Oral↗
PubMed1999

[Involvement of nitric oxide in itch-scratch response of NC mice].

NC mice, a model for atopic dermatitis, showed scratching behavior when kept under conventional environment. The scratching behavior of NC mice was suppressed by distraction or by the administration of naltrexone (1 mg/kg, s.c.), an opioid antagonist. These results suggest that such scratching behavior is itch-associated response. The itch-associated response of the NC mice was significantly suppressed by an intravenous injection of nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg), but not D-NAME (10 mg/kg) and saline. Intracutaneous NO production in the rostral back, a region which the NC mice mainly scratched, was markedly increased as compared with the caudal back, a non-scratched region. The increased NO production in the rostral back of NC mice was decreased by the intravenous injection of L-NAME (10 mg/kg). These results suggest that NO and NO synthase are new target in the treatment of atopic pruritus.

Animals↗
PubMed1999

Reduced urination rate while drinking beer with an unpleasant taste and off-flavor.

A lowered subjective evaluation of the taste and flavor of beer due to staleness or to the addition of an unpleasant taste and flavor was found to be closely correlated with the urination rate. Beer in the same lot was compared immediately after shipment from the brewery and after leaving at room temperature for 1 month or 5 months. Each beer sample was given to volunteers at the rate of 3 ml/kg/15 min for 2 hours, and the urine volume was measured every 30 minutes. The urination rate was highest from the volunteers who drank fresh beer and lowest from those who drank 5-month-old beer. The subjective evaluation of both the taste and drinkability of 5-month-old beer was significantly lower than that of fresh beer. Beer samples with various unpleasant taste and flavor substances added lowered the urination rate. The results suggest that the perception of an unpleasant taste and off-flavor would lower the urination rate.

Adult↗
PubMed1999

Sequence comparison of the VP2 variable region of infectious bursal disease virus isolates from Vietnam.

The variable region in the VP2 gene of twenty-three infectious bursal disease virus (IBDV) isolates, collected in Vietnam in 1997 and 1998, was amplified as cDNA by using the reverse transcription-polymerase chain reaction and sequenced. Analysis of amino acid substitutions and phylogenetic relationships of the deduced amino acid sequences (residues 206-350) showed that the nineteen Vietnamese vv IBDVs clustered with the European vv IBDVs, Japanese vv IBDVs and Chinese vv strains, and that the four vietnamese virulent strains were closely related to European virulent strain 52/70. These results suggest that Vietnamese vv IBDVs, European vv IBDVs, Japanese vv IBDVs and Chinese vv strains have the same origin.

Amino Acid Sequence↗
PubMed1999

Characterization of monoclonal antibodies to human protein 1/Clara cell 10 kilodalton protein.

Human protein 1/Clara cell Mr 10,000 protein consists of two identical subunits of seventy amino acid residues each. In the present study, eight clones of monoclonal antibodies against native protein 1 were prepared and their respective epitopes were immunochemically and immunohistochemically characterized using native protein 1, truncated recombinant protein 1 and synthesized peptides. Among the clones, three designated as TY-5, TY-7 and TY-8 recognized amino acid residues 7-16, residues 19-28, and residues 39-46, respectively, all of which comprise the hydrophobic cavity of protein 1, possibly associated with chemical binding function. With the exception of TY-4, the remaining clones recognized residues 61-68 which are exposed to solvent. The epitope of TY-4 remains undetermined. Proper selection and combination of clones and recombinant protein 1 may be useful for fundamental and clinical studies of protein 1.

Amino Acid Sequence↗
PubMed1999

Morphological effects on in-stent restenosis assessed by intravascular ultrasound imaging.

The purpose of this study was to evaluate the rupture and dissection of the vessel wall immediately after balloon dilatation by intravascular ultrasound (IVUS) imaging and to predict restenosis in patients who underwent subsequent coronary stent implantation. Stent implantation improves the long-term results of coronary angioplasty by reducing lesion elastic recoil and arterial remodeling. However, several studies have suggested that neointimal hyperplasia is the cause of instant restenosis. We recruited 60 patients in whom IVUS studies were performed immediately after successful balloon dilatation and just before stent implantation. We compared IVUS parameters with 6-month follow-up quantitative coronary angiography. This was performed in 51 lesions of 51 patients (85%). Qualitative analysis included assessment of plaque composition, plaque eccentricity, plaque fracture and the presence of dissection. In addition, minimal luminal diameter, percent diameter stenosis, percent area stenosis and plaque burden were quantitatively analyzed. Two morphological patterns after balloon dilatation were classified by IVUS. Type I was defined as absence or partial tear of the plaque without disclosure of the media to lumen (22 lesions). Type II was defined as a split in the plaque or dissection of the vessel wall with disclosure of the media to the lumen (29 lesions). At 6 months follow-up, angiographic restenosis occurred in 17 of the 51 lesions (33%). Restenosis was significantly (p < 0.05) more likely to occur in type II (13/29: 45% incidence) than in type I (4/22: 18% incidence). The assessment of plaque morphology immediately after balloon dilatation and before stent implantation provides important therapeutic and prognostic implications.

Aged↗
PubMed1999

A simple technique for anatomical slow pathway ablation in atrioventricular nodal reentrant tachycardia.

The slow pathway potential or the slow potential serves as a useful marker in catheter ablation of the slow pathway. However, an anatomical approach without recording of these potentials is also an effective way to cure atrioventricular nodal reentrant tachycardia (AVNRT). Moreover, the origin of these potentials is a matter of controversy. We compared 2 approaches to ascertain whether or not recording of these potentials is necessary in eliminating the slow pathway and to estimate the usefulness of the simple anatomical approach. The study population consisted of 24 patients with a conventional approach (Group P) and 19 patients with an anatomical approach (Group A). In group A, the ablation site was determined by fluoroscopy, which was the lowest one-third of the area between the His bundle electrogram recorded position and the coronary sinus orifice at the right anterior oblique view, and just in front of and above the coronary sinus orifice also posterior to the His catheter at the left anterior oblique view where the His catheter was seen tangentially. The slow pathway was successfully ablated in all patients without any complications, including more than first-degree AV block. Although there were no significant differences in total energy or number of applications between the 2 groups, the procedure time was significantly shorter in group A (p < 0.01). In conclusion, recording of the slow pathway potential or the slow potential is not always necessary for slow pathway ablation in the treatment of AVNRT. Because our anatomical approach was performed simply, effectively and safely, it is recommended for the slow pathway ablation of AVNRT.

Adolescent↗
PubMed1999

A cholesteryl ester transfer protein gene mutation and vascular disease in dialysis patients.

Among patients undergoing maintenance hemodialysis, a decreased high-density lipoprotein cholesterol (HDL-C) concentration is among the most common abnormalities of lipid metabolism and apparently is an independent risk factor for vascular disease. A common missense mutation of cholesteryl ester transfer protein gene, D442G (Asp 442 to Gly), increases HDL-C levels through the reduced activity of cholesteryl ester transfer from HDL to VLDL, but the mutation also may lead to reduced activity of reverse cholesterol transport. To investigate the effect of the D442G polymorphism on atherosclerotic complications in dialysis patients, the genotype and allele frequency of the polymorphism were determined in 414 unselected dialysis patients and 220 control subjects, and postprandial serum lipid levels were measured in the dialysis patients. A similar genotype distribution was found between hemodialysis patients and healthy control subjects, and in dialysis patients with and without vascular disease. Serum levels of total cholesterol and HDL-C did not differ between patients with and without the mutation and in patients with and without vascular disease. However, patients with sub-median HDL-C levels (<45 mg/dl) had an independent odds ratio of 1.8 for vascular disease (95% confidence interval, 1.04 to 3.2; P < 0.05). In this low-HDL-C subgroup, patients with the D442G mutation had a significantly higher prevalence of vascular disease than those with no mutation (54.5% versus 24.4%; P < 0.05), and an independent odds ratio of 4.9 (95% confidence interval, 1.05 to 22.65; P < 0.05). In conclusion, the D442G mutation is an independent risk factor for atherosclerotic complications in dialysis patients with HDL-C levels below 45 mg/dl.

Adolescent↗
PubMed1999

Cell-substratum adhesion is suppressed by high pressure.

The effects of high pressure (0.1-80 MPa) on cell adhesion were examined using Chinese hamster ovary cells. The cells detached by EDTA or trypsin were cultured for 4 h at atmospheric pressure. In each case, the rate of the adhesive cells was about 85%. Upon the addition of cycloheximide, such cell adhesion was almost completely inhibited in trypsin-treated cells but less affected in EDTA-treated cells. When the EDTA-detached cells were subjected to high pressures and cultured at atmospheric pressure, the cell adhesion was unaffected up to 40 MPa, but was suppressed significantly at higher pressures although the integrins were expressed on the plasma membranes. The suppressive effects induced by high pressure (80 MPa) were marked in trypsin-treated cells, in which the integrins were digested. Furthermore, actin stress fibers in spread cells disappeared due to cell rounding upon exposure to 80 MPa, and such rounded cells were partially detached from the substratum. These results suggest that the retardation of adhesion by high pressure in EDTA-detached cells may be due to the perturbed interactions between integrin and its associated proteins, whereas that of trypsin-detached cells is due to the delayed expression of integrins toward the membrane surface, in addition to the cause seen in the case of EDTA.

Animals↗