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S Okamoto

Publications and source records attributed to S Okamoto.

At least 343 records · Page 19Linked to original sources
PubMed1995

Decreased sensitivity to beta-adrenergic stimulation of the ventricular cells isolated from the spontaneously hypertensive rat heart.

1. The stimulatory effects of isoproterenol on the L-type Ca2+ current (ICa) were compared between the control (WKY) and hypertensive (SHR) rat heart cells, using the patch-clamp method. 2. The current density and the shape of the current-voltage relationship for ICa were not different between the two groups. However, the maximal percentage increase in response to isoproterenol was smaller in SHR (+91% in SHR and +81% in WKY), and the ED50 was significantly higher in SHR (0.081 mu mol/L in SHR and 0.020 mu mol/L in WKY). IBMX, a potent phosphodiesterase inhibitor, significantly increased the isoproterenol-stimulated ICa in SHR, but not in WKY. These results suggest an impaired cAMP production in SHR heart cells.

1-Methyl-3-isobutylxanthine↗
PubMed1995

Supernumerary impactions of the mandibular cuspids and bicuspids. Case report.

A case involving the presence of supernumerary cuspids and bicuspids is described. The condition was probably an inherited one because of the family history and the bilateral incidence. The supernumerary teeth erupted because of alveolar resorption in which inflammatory factors probably played a role. Radiographic follow-up of the site of supernumerary impacted teeth and alveolar resorption should be undertaken.

Aged↗
PubMed1995

Hepatic cholesterol 7 alpha-hydroxylase activity and serum 7 alpha-hydroxy-cholesterol level during liver regeneration after partial hepatectomy in rats.

Hepatic cholesterol 7 alpha-hydroxylase is a rate-limiting enzyme for bile acid synthesis, and we have previously shown that the serum 7 alpha-hydroxycholesterol level reflects the enzyme activity in patients with an intact liver. The purpose of this study was to evaluate the alterations in hepatic cholesterol 7 alpha-hydroxylase activity and the serum 7 alpha-hydroxycholesterol level after hepatectomy and the correlations between these parameters and liver mass. Hepatic cholesterol 7 alpha-hydroxylase activity, the serum 7 alpha-hydroxycholesterol level and the remaining liver weight were determined after 70% hepatectomy in rats. Cholesterol 7 alpha-hydroxylase activity was decreased on days 1 and 2 (from 28.3 +/- 3.7 to 8.5 +/- 2.8 and 13.3 +/- 3.6 pmol/min/mg protein, respectively), returned to the preoperative level on day 3 (24.7 +/- 2.6 pmol/min/mg protein) and further elevated thereafter (71.4 +/- 10.9 on day 7 and 51.3 +/- 6.6 pmol/min/mg protein on day 14). The serum level of 7 alpha-hydroxycholesterol changed simultaneously with the enzyme activity, and a significant correlation between the two parameters was observed (r = 0.915, p < 0.0001). The correlations between the liver weight and hepatic cholesterol 7 alpha-hydroxylase activity and serum 7 alpha-hydroxycholesterol level were significant (p < 0.01), but the significances disappeared for the period of days 3-14 (r = 0.424, p = 0.08; r = 0.299, p = 0.228, respectively). In conclusion, hepatic cholesterol 7 alpha-hydroxylase activity is suppressed by hepatectomy and then activated as the liver regenerates. The serum 7 alpha-hydroxycholesterol level is a good parameter of this enzyme activity after partial hepatectomy.

Animals↗
PubMed1995

Application of a unique automated synthesis system for solution-phase peptide synthesis.

An automated synthesis system, which is suitable for repetitive syntheses using similar reaction procedures, was used to synthesize systematically a library of all possible dipeptides (25) and tripeptides (125) from 5 protected amino acids. The apparatus has also been applied to the automated synthesis of 10 fragment tripeptide derivatives that are constituents of the hormone PACAP-27. The measured molecular optical rotation values of the library of 125 tripeptides were found to correlate well with calculated values obtained by summation of the molecular optical rotation values for the constituent amino acids.

Amino Acid Sequence↗
PubMed1995

Does dopamine act on myocardial cells?

We examined the electrophysiological effects of dopamine on the single myocardial cells isolated from the rat and rabbit heart. Dopamine at a concentration of 1 or 10 microM did not affect the L-type Ca2+ current (ICa) or the transient outward current (ITO) in rat ventricular, rabbit atrial, ventricular, and sinoatrial node cells. It did not induce any detectable change in the action potential configuration of the rabbit ventricular cells either. We conclude that dopamine does not directly act on myocardial cells at least in terms of the electrophysiological properties.

Action Potentials↗
PubMed1995

Helicobacter pylori infection is associated with low antral somatostatin content in young adults. Implications for the pathogenesis of hypergastrinemia.

BACKGROUND: Recent studies on the role of Helicobacter pylori in the pathogenesis of duodenal ulcers have focused on the mechanism by which H. pylori infections cause exaggerated gastrin release. METHODS: We determined meal-stimulated serum gastrin concentrations and antral somatostatin content in 24 asymptomatic volunteers (6 H. pylori-infected, 18 H. pylori-uninfected). Somatostatin content was determined by radioimmunoassay in biopsy specimens obtained from the antrum. RESULTS: Fasting and integrated 2-h gastrin concentrations were significantly higher in H. pylori-positive volunteers than in H. pylori-negative volunteers (fasting, 111 +/- 16.3 pmol/l versus 53.4 +/- 3.5 pmol/l; p < 0.05; integrated 2-h, 267 +/- 41.2 pmol/l versus 70.1 +/- 2.1 pmol/l; p < 0.01). Antral somatostatin content was 0.764 +/- 0.173 ng/mg and 2.931 +/- 0.414 ng/mg in H. pylori-positive and -negative volunteers, respectively (p < 0.01). CONCLUSIONS: Low antral somatostatin content may cause hypergastrinemia in asymptomatic healthy volunteers, and H. pylori may contribute to the pathogenesis of duodenal ulcer, through this mechanism.

Adult↗
PubMed1995

Helicobacter pylori infection, serum gastrin, and gastric acid secretion in teen-age subjects with duodenal ulcer, gastritis, or normal mucosa.

BACKGROUND: Many studies have confirmed the close association of Helicobacter pylori with duodenal ulcer (DU) in adults. However, in the subtype of DU known as 'childhood' or 'early onset DU' genetic factors seem to play a prominent role in the pathogenesis. The aim of this study was to investigate the prevalence of H. pylori in teen-age subjects with DU, gastritis, and normal mucosa and to examine the relationship of H. pylori to serum gastrin levels and gastric acid secretion. METHODS: Sixty-one teen-age subjects (24 with DU, 14 with gastritis, and 23 normal subjects) were investigated for the presence of H. pylori, antral histology, gastrin levels, basal acid output (BAO), and maximal acid output (MAO). RESULTS: All 24 patients with DU and 8 of 14 with gastritis were infected with H. pylori; none of the normal subjects were infected. Mean gastritis scores and fasting serum gastrin levels were significantly higher in patients with DU or H. pylori-positive gastritis than in subjects with H. pylori-negative gastritis or normal mucosa (p < 0.05). The difference in serum gastrin levels was also significant when patients with DU were compared with those with H. pylori-positive gastritis (p < 0.05). BAO and MAO were significantly higher in patients with DU than in subjects with H. pylori-positive gastritis or normal mucosa (p < 0.05), but there was no difference between subjects with H. pylori-positive gastritis and those with normal mucosa. CONCLUSION: H. pylori infection is associated closely with teen-age DU and gastritis and with hypergastrinemia but does not affect BAO and MAO in most infected teen-age subjects.

Adolescent↗
PubMed1995

[The effects of information relevance to speaker vs. hearer on the use of comment expressions and interrogative sentences in the Japanese language].

This study examined how the relevance of information to the speaker and the hearer affected the use of comments and interrogative sentences. Subjects read scenarios and rated the necessity of an expression (Experiment 1) or the naturalness of expressions (Experiment 2) in each of the situations. Experiment 1 investigated the use of comments, which preceded the information, to show the speaker's uncertainty about the information contents (subjects: 138 undergraduates). The less the information was relevant to the speaker and/or the more it was relevant to the hearer, the more the comments were judged to be necessary. Experiment 2 investigated the use of interrogative sentences, declarative sentences, and declarative sentences + a sentence final particle 'ne' (subjects: 96 undergraduates). Interrogative sentences were judged to be the most natural in the conditions where the information was relevant to the hearer and not to the speaker, whereas declarative sentences were judged to be the most natural where the information was relevant to the speaker and not to the hearer. Declarative sentences + 'ne' showed intermediate patterns of use between interrogative sentences and declarative sentences.

Adult↗
PubMed1995

Placement of the urethral stent made of shape memory alloy in management of benign prostatic hypertrophy for debilitated patients.

PURPOSE: A new urethral stent made of shape memory alloy was placed to relieve prostatic obstruction in 17 patients in whom other approaches were contraindicated. MATERIALS AND METHODS: All patients were unable to tolerate intervention with sedation and positioning. Placement of the shape memory alloy stent mounted on a 16F Foley catheter is similar to insertion of a urethral catheter except for the heat-sensitive expansion. RESULTS: Each device was easily implanted with the patient on a flat examination table. There was no migration or incrustation of the shape memory alloy stent during the indwelling period. CONCLUSIONS: Clinical results demonstrate that the shape memory alloy urethral stent might be the only choice for management of prostatic obstruction in debilitated patients.

Aged↗
PubMed1995

Pernicious anemia and Helicobacter pylori infection in Japan: evaluation in a country with a high prevalence of infection.

OBJECTIVES: To evaluate the degree of gastritis and the prevalence of Helicobacter pylori in Japanese patients with pernicious anemia (PA). METHODS: Histological assessment for mucosal atrophy and inflammation was performed in gastric biopsy specimens taken from 24 Japanese patients with PA and from 24 age- and sex-matched controls. The prevalence of H. pylori was evaluated by Giemsa staining and serum IgG antibodies. Serum gastrin and pepsinogens were determined by radioimmunoassay. RESULTS: All patients with PA had severe fundic atrophic gastritis, and 17 (71%) also had antral atrophic gastritis. Thirteen (54%) of 24 age- and sex-matched controls had fundic atrophic gastritis, and 15 (62%) also had antral atrophic gastritis. Mucosal inflammation was identified in the fundus of all 24 patients and in 15 (62%) controls and in the antrum of 22 (92%) patients and 16 (67%) controls. H. pylori was not detected by Giemsa staining or serum IgG antibodies to H. pylori in any patient with PA but was present in 16 (67%) controls. Serum gastrin levels were significantly higher, and serum pepsinogen I, II, and the I/II ratio were significantly lower in patients than in controls (p < 0.001). CONCLUSIONS: Our results confirm that H. pylori infection is infrequent in PA and is unlikely to be a factor in producing type A gastritis in PA.

Adult↗
PubMed1995

[A preliminary analysis of unrelated marrow transplantations facilitated by the Japan Marrow Donor Program (JMDP)].

Between January 1993 and June 1994, the JMDP facilitated marrow donations from unrelated donors for 171 patients with malignant and non-malignant disorders. The median age of the patients was 21 years. All patients received marrow from phenotypically HLA -A, -B, -DR identical donors. About half of the patients wrer treated with total body irradiation (TBI)-containing regimens and about 80% of the patients received short-courses methotrexate and cyclosporine for graft-versus-host disease (GVHD) prophylaxis. Eight out of 171 patients, (4.7%) had graft failure and 63 out of 144 patients (44%), who survived for more than 30 days posttransplant, developed grade II to IV acute GVHD. The incidence of chronic GVHD was 47% (extensive form; 27%); most of them were progressive/quiscent type. The incidence of moderate to severe acute GVHD was higher than that observed in sibling transplants. On the other hand, the incidence of chronic GVHD was similar to that observed in sibling transplants. Overall survival at 1.5 years posttransplant was about 50% with no significant differences between diseases. The age correlated significantly with the survival in standard risk leukemia but not in high-risk leukemia. Despite the risk of graft failure and acute GVHD, this preliminary analysis demonstrates that transplantation of marrow from unrelated donors can be an effective treatment for certain hematologic disorders.

Acute Disease↗
PubMed1995

[MRI of traumatic anosmia].

On MRI, the authors were able to demonstrate the contused lesions of bilateral rectal gyri near the crista galli in all of five cases of traumatic anosmia. Thin slice coronal and sagittal images of MRI were very useful for detecting the lesions. Conventional CT scans failed to demonstrate the lesions in 3 out of the 5 cases, but, even in these cases, MRI was able to clearly depict the contused lesions of bilateral rectal gyri. Therefore, the depicted lesions of bilateral rectal gyri on MRI can be evidence of traumatic anosmia and this may be very significant in medico-legal cases.

Adolescent↗
PubMed1995

Implications of host pancreatic hormones in the restart of grafted liver.

Regulatory roles of insulin and glucagon in hepatic metabolism and function are well described. However, little is known about implications of host pancreatic hormones in primary function of grafted liver. This study aimed to investigate it in relation to hepatic mitochondrial function. Insulin, c-peptide, and glucagon in peripheral blood were monitored for 2 days in clinical liver transplantation by a continuous sampling technique to avoid influences of hormonal oscillation. In grafts with immediate function (n = 10), smooth increase of arterial ketone body ratio reflecting hepatic intramitochondrial redox state was accompanied by increased c-peptide and decreased glucagon, resulting in the increase of c-peptide/glucagon ratio. In other functioning grafts (n = 20), where ketone body ratio was rather lower, increased glucagon level, observed also during anhepatic phase, resulted in the slower increase of c-peptide/glucagon ratio. There were accompanied by increased free fatty acid and ketone body levels. In primary nonfunction (n = 4), rapid increase of c-peptide accompanied by hyperglycemia resulted in the accelerated increase of c-peptide/glucagon ratio, but ketone body ratio did not show any increase. Insulin/c-peptide ratio also showed a rapid increase. These findings suggest that the increase of insulin/glucagon ratio in portal blood, potentially influenced by recipient condition, is associated with the recovery of mitochondrial energy metabolism in survived hepatic grafts. However, this relationship does not work in failed grafts, where irreversible impairment of energy metabolism is attributed to graft itself.

Adolescent↗
PubMed1995

[Aplastic anemia complicated with secondary hemochromatosis after allogenic bone marrow transplantation].

We report a case of aplastic anemia complicated with secondary hemochromatosis after allogenic bone marrow transplantation (BMT). A 29-year-old man was diagnosed as having aplastic anemia at the age of 8. At the age of 28, BMT was performed from his HLA-identical sister. Total volume of blood transfusion before BMT was about 28,000 ml, and in three months after BMT was 8,000 ml. The transplantation was successful, but one month after BMT, dry eyes, skin pigmentation and hepatomegaly appeared. Serum bile duct enzymes and ferritin also increased remarkably. Moreover after thirteen months, glucose tolerance impaired seriously. Abdominal computed tomography (CT) revealed atrophic pancreas and an increased CT density in the liver and the tail of the pancreas. A large amount of iron deposition were also found in liver and stomach biopsy specimens. We concluded that diabetes mellitus was due to secondary hemochtomatosis in the present case. There is a possibility that tissue damage due to iron deposits may have been accelerated through BMT in this patient with a history of many blood transfusions.

Adult↗
PubMed1995

Effect of Helicobacter pylori eradication on the healing and recurrence of peptic ulcer: combination therapy with low-dose omeprazole and clarithromycin.

AIM: To investigate the effect of eradication of Helicobacter pylori using combination therapy with low-dose omeprazole and clarithromycin on the healing and recurrence of peptide ulcers. PATIENTS AND METHODS: We studied 60 patients with active duodenal ulcers and 60 with gastric ulcers who were H. pylori-positive by the rapid urease test and a histological examination of antral biopsy specimens. The eradication method used was a combination of omeprazole (20 mg a day) and clarithromycin (400 mg twice a day). The patients were followed up for 24 months after the end of the treatment. H. pylori infection and the ulcer stage were investigated by endoscopy every 6 months. We assessed the relationship between H. pylori infection, ulcer healing to a white scar and ulcer recurrence after combination therapy. RESULTS: H. pylori was eradicated in 23 out of 120 patients (22%), with suppression in 101 out of 120 patients (84%). The rate of ulcer healing to a white scar 6 months after treatment was significantly higher and the ulcer recurrence rate within 2 years after treatment was significantly lower in patients with H. pylori suppression or eradication than in those continuously positive for the organism. CONCLUSIONS: These results suggest that not only the eradication but also the suppression of H. pylori may improve ulcer healing and reduce the rate of relapse.

Adult↗
PubMed1995

Characterization of immortalized rabbit corneal epithelial cells with SV40 large T antigen.

The authors developed a line of immortalized rabbit corneal epithelial cells by transfecting a primary culture of New Zealand White (NZW) rabbit corneal epithelial cells with Simian virus 40 (SV40) T antigen gene using a calcium phosphate precipitation method. The transfected cells, which survived more than 40 passages and 400 population doublings, showed some ability to form colonies in soft agar, and had doubling times and plating efficiencies not significantly different from those of untransfected cells. The epithelial nature of the transfected cells was confirmed by immunofluorescence staining with the antibody to 64 kD keratin (AE5), a specific marker for corneal type epithelial cells. Immunofluorescence microscopic examination revealed that the transfected cells expressed major basement membrane components of epithelial cells, including collagen types IV and VII and laminin. Electron microscopic studies demonstrated the presence of microvilli and intercellular in cultured transfected cells. These results indicate that the transfected cells retain some of the normal phenotypic characteristics of corneal epithelial cells and may therefore be used to study the corneal epithelium in vitro.

Animals↗