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S Okamoto

Publications and source records attributed to S Okamoto.

At least 127 records · Page 7Linked to original sources
PubMed2000

Role of hypotension in brain-death associated impairment of liver microcirculation and viability.

Hypotension in brain-dead organ donors is considered a determinant factor of graft viability. The aim of this study was to elucidate the role of hypotension in brain-death associated impairment of hepatic microcirculation and function. Male Sprague-Dawley rats with an intracranial balloon were used. Group I (n = 7) served as sham controls. In group II (n = 7) brain death was induced through inflation of an intracranial balloon. In group III (n = 7) hypotension without brain death was induced by means of pentobarbital. In group II, a steep rise of arterial pressure was followed by a fall to a lower level (P < 0.01, vs. group I). Also in group III arterial pressure was lower (P < 0.01, vs. group I). In group II, bile production was diminished (P < 0.05). Impaired sinusoidal perfusion (P < 0.01) and enhanced leukocyte endothelium interaction (P < 0.05) were documented in hepatic microvasculature. Electron microscopic analysis revealed vacuolization of hepatocytes; these changes were not observed in group III. Brain death induces specific changes of liver microcirculation, function and histomorphology. Independent of associated hypotension, brain death per se impairs donor liver graft quality.

Alanine Transaminase↗
PubMed2000

Intraosseous microcystic meningioma.

Extradural ectopic meningioma is a rare tumor. We report on an example of microcystic meningioma arising in the skull of an elderly woman. Radiological examination revealed a localized osteolytic lesion in the left parietal bone. At surgery, it was discovered that the tumor was located within the skull without any evidence of extraosseous extension. The light microscopic, immunohistochemical and ultrastructural features were consistent with a microcystic variant of meningioma. To our knowledge, this is the first case of an intraosseous microcystic meningioma, and we believe that this type of meningioma should be considered in the differential diagnoses of myxoid bone tumors of the calvarium.

Aged↗
PubMed2000

Monitoring of occupational exposure to tetrachloroethene by analysis for unmetabolized tetrachloroethene in blood and urine in comparison with urinalysis for trichloroacetic acid.

OBJECTIVE: The present study was initiated to examine a quantitative relationship between tetrachloroethene (TETRA) in blood and urine with TETRA in air, and to compare TETRA in blood or urine with trichloroacetic acid (TCA) in urine as exposure markers. METHODS: In total, 44 workers (exposed to TETRA during automated, continuous cloth-degreasing operations), and ten non-exposed subjects volunteered to participate in the study. The exposure to vapor was monitored by diffusive sampling. The amounts of TETRA and TCA in end-of-shift blood and urine samples were measured by either head-space gas chromatography (HS-GC) or automated methylation followed by HS-GC. The correlation was examined by regression analysis. RESULTS: The maximum time-weighted average (TWA) concentration for TETRA-exposure was 46 ppm. Regression analysis for correlation of TETRA in blood, TETRA in urine and TCA in urine, with TETRA in air, showed that the coefficient was largest for the correlation between TETRA in air and TETRA in blood. The TETRA in blood, in urine and in air correlated mutually, whereas TCA in urine correlated more closely with TETRA in blood than with TETRA in urine. The TCA values determined by colorimetry and by the GC method were very similar. The biological marker levels at a hypothetical exposure of 25 ppm TETRA were substantially higher in the present study than were the levels reported in the literature. Possible reasons are discussed. CONCLUSIONS: Blood TETRA is the best marker of occupational exposure to TETRA, being superior to the traditional marker, urinary TCA.

Adult↗
PubMed2000

Activating Gs(alpha) mutation in intramuscular myxomas with and without fibrous dysplasia of bone.

Activating missense mutations in the Arg 201 codon of the gene encoding the alpha subunit of Gs, the G protein that stimulates cAMP formation, have been recognized as the cause of many endocrine diseases, McCune-Albright syndrome and isolated fibrous dysplasia of bone. On the other hand, intramuscular myxomas with fibrous dysplasia, so-called Mazabraud's syndrome, have been sporadically reported, but it has not been confirmed whether intramuscular myxoma, with or without fibrous dysplasia, is associated with the Gs(alpha) mutations. We investigated the presence of the Gs(alpha) mutations in intramuscular myxomas with or without fibrous dysplasia by a PCR-SSCP assay, using formalin-fixed, paraffin-embedded tissues. In five of the six intramuscular myxomas (three with and two without fibrous dysplasia), point mutations were detected as aberrant bands by SSCP, which were confirmed by a subsequent sequence analysis (three Arg to His and two Arg to Cys). This result suggests that the Gs(alpha) mutations are related to tumorigenesis in intramuscular myxoma and that intramuscular myxoma is one of the diseases induced by abnormal Gs(alpha) protein.

Adult↗
PubMed2000

Overexpression of Fas-ligand by neuroblastoma: a novel mechanism of tumor-cell killing.

BACKGROUND/PURPOSE: Binding of Fas ligand (Fas-L) to the membrane-bound Fas receptor incites a series of intracellular events that results in programmed cell death or apoptosis. Although this apoptotic phenomenon plays a key role in down-regulating cytotoxic T cells, the authors have shown previously that pancreatic beta cells (bTC) overexpressing Fas-L paradoxically undergo accelerated rejection that is dependent on a Fas/Fas-L interaction. This study evaluates whether a neuroblastoma (NB) cell line manipulated to overexpress Fas-L undergoes similar destruction and whether tumor-specific protective immunity can be produced. METHODS: The authors transfected NB cells (SK-N-MC) with either mFas-L cloned into a pcDNA3.1/Zeo plasmid vector (NB/Fas-L) or with the vector alone (NB/control). Successful transfection of Fas-L was characterized by reverse transcription polymerase chain reaction (RT-PCR) and the ability of transfectants to induce apoptosis of Fas-sensitive T cells (Jurkat). Expression of Fas and Fas-L in untransfected NB clones was characterized by immunohistochemistry and RNase protection assay (RPA). Apoptosis was measured by FACScan analysis using an Annexin V assay. A total of 3x10(6) NB/control and NB/Fas-L cells were implanted subcutaneously into the hind leg of Balb/C SCID mice. Tumor-specific protective immunity was also tested in this model by inoculating mice with NB/Fas-L before implanting NB/control cells. RESULTS: Zeocin resistance and RT-PCR confirmed successful transfection of Fas-L into NB cells. Fas Ligand transfectants induced apoptosis in 17.6%+/-2.9% of Fas-sensitive T cells, whereas controls induced apoptosis in only 2.8%+/-1.2% (P = .01, n = 3). Although Fas appears to be constitutively expressed by NB in low amounts, introduction of Fas-L into NB cells did not induce suicide or affect tumor cell growth in vitro. In vivo, NB cells expressing Fas-L failed to grow in SCID mice (n = 3), whereas controls grew rapidly in all animals until death (n = 3). NB/control cells implanted into the opposite leg of mice that rejected initial NB/Fas-L transfectants also grew rapidly (n = 3) implying no protective immunity. CONCLUSIONS: Overexpression of Fas-L in NB clones targets such cells for rapid destruction even in immune compromised hosts, suggesting potential utility of Fas-L in combating NB. In this SCID mouse model, the observed effect is probably neutrophil mediated and does not provide tumor-specific protective immunity.

Animals↗
PubMed2000

Differential apoptosis gene expression in pediatric tumors of the kidney.

BACKGROUND/PURPOSE: Apoptosis, or programmed cell death, is essential in maintaining normal homeostasis of tissues. The process of apoptosis is controlled by numerous pro- and antiapoptotic factors. Variations in expression of such factors may account for some variations in tumor behavior. This study evaluates the expression of apoptotic mRNA species in pediatric renal tumors to determine whether a pattern of differential apoptosis gene expression correlates with tumor grade and type. METHODS: Twenty-five frozen tissue specimens were obtained from patients undergoing biopsy or resection of pediatric renal tumors before chemotherapy: Wilms' tumor stage II (WT-II, n = 4); Wilms' tumor stage III/IV (WT-III/IV, n = 4); clear cell sarcoma of the kidney stage III (CCSK, n = 2); rhabdoid tumor of the kidney stage III/IV (RTK, n = 4); and normal kidney (NK, n = 11). An RNase Protection Assay (RPA) was performed for 19 pro- and antiapoptotic mRNA species to detect and quantify expression (percentage of GAPDH expressed). Expression of specific mRNAs of interest were confirmed by Western Blot (WB). RESULTS: The expression of apoptotic mRNA species varied markedly between tumors. WT-II expressed greater amounts of proapoptotic receptor mRNA than CCSK or RTK. (Fas, 17.0+/-2.7% v. 2.5+/-0.5% v. 3.3+/-0.9%; P<.02; DR5, 77.0+/-8.8% v. 13.5+/-0.5% v. 27.0+/-4.8; P<.001; TNF-R, 71.3+/-17.0% v. 21.0+/-4.0% v. 29.0+/-5.0%; P<.07, respectively). Surprisingly, antiapoptotic factors (e.g., bcl-2 and bcl-xl) were not overexpressed in poor prognostic tumors (CCSK, RTK) compared with those with good prognosis (WT). Expression of TRAIL (a ligand for DR4 and DR5) was significantly lower in CCSK and RTK than in normal kidney (9.5+/-1.5% v. 56.1+/-10.1%; P = .01). CONCLUSIONS: Proapoptotic receptors are expressed at greater levels in good prognostic tumors, and this finding is compatible with their clinical behavior. Knowledge of differential apoptotic gene expression is of potential value in predicting prognosis and treating such tumors with targeted ligands.

Apoptosis↗
PubMed2000

Effect of Helicobacter pylori eradication on subsequent development of cancer after endoscopic resection of early gastric cancer in Japan.

This article describes the characteristics of H. pylori infection dynamics in early gastric cancer cases in Japan and the reduced likelihood of metachronous cancer development and growth inhibition by H. pylori eradication based on healing of background gastric mucosa. In the future, these clinical studies and experimental studies in Mongolian gerbils and mice should elucidate the role of H. pylori infection in the development of gastric carcinogenesis to clinical cancer on the genetic level so that gastric cancer prevention by H. pylori eradication is established.

Gastroscopy↗
PubMed2000

Synthesis and structure-activity relationships of a new class of selective EP3 receptor agonist, 13,14-didehydro-16-phenoxy analogues of prostaglandin E1.

A series of 13,14-didehydro-16-phenoxy analogues of prostaglandin E1 was synthesized and their agonistic activity on EP receptor subtypes was evaluated. 13,14-Didehydro-16-phenoxy-1-decarboxy analogues, 7e and 7f, display highly selective activity on the EP3 receptor subtype, thus, their utility as a selective anti-ulcer agent can be expected.

Alprostadil↗
PubMed2000

COL1A1-PDGFB fusion transcripts in fibrosarcomatous areas of six dermatofibrosarcomas protuberans.

The fibrosarcomatous transformation of dermatofibrosarcoma protuberans (DFSP) has been considered for some time to be associated with an adverse clinical outcome. However, the molecular and cellular mechanism underlying the tumor progression remains undetermined. As the chimeric gene, COL1A1-PDGFB, has been proposed to play an important role in the histogenesis of DFSP, we conducted a reverse transcription-polymerase chain reaction assay to ascertain whether the COL1A1-PDGFB fusion transcripts can be detected in both conventional DFSP and fibrosarcomatous components of DFSP with fibrosarcomatous areas (DFSP-FS), using a simple method of microdissection on sections of archival formalin-fixed, paraffin-embedded tumor specimens from six DFSP-FS cases. The COL1A1-PDGFB fusion transcripts could be detected in FS areas in five of the six cases, whereas conventional DFSP areas of all cases expressed the chimeric mRNA. A subsequent sequence analysis of the polymerase chain reaction products confirmed that the detected messages were derived from identical gene fusions in the two different components of each of the five cases. Our results verify that the COL1A1-PDGFB fusion transcripts are preserved in the FS areas of most DFSP-FSs. The expression of the fusion transcripts in both conventional DFSP and FS areas of DFSP-FS supports a common histogenesis of the two components.

Adolescent↗
PubMed2000

Risk-adapted pre-emptive therapy for cytomegalovirus disease in patients undergoing allogeneic bone marrow transplantation.

We prospectively evaluated a risk-adapted pre-emptive treatment with ganciclovir for CMV diseases in patients undergoing allogeneic bone marrow transplantation (BMT). High-level CMV antigenemia (10 or more positive cells on two slides) or CMV antigenemia at any level in patients with grade II-IV acute graft-versus-host disease (aGVHD) were chosen as risk factors. We also retrospectively evaluated virus reactivation in plasma using quantitative real-time polymerase chain reaction (PCR). Fifty patients were evaluable. None of the 27 patients with or without grade I aGVHD developed high-level CMV antigenemia or CMV disease. Among the 23 patients with grade II-IV aGVHD, 12 patients (52%) developed CMV antigenemia and were treated pre-emptively, of whom two developed CMV gastroenteritis or retinitis in spite of therapy. Six of the remaining 11 patients developed CMV gastroenteritis before CMV antigenemia was detectable. All of the eight patients with CMV diseases were successfully treated with ganciclovir and no deaths directly related to CMV disease occurred. In four of the seven evaluable patients with CMV gastroenteritis, real-time PCR was able to detect virus reactivation earlier than CMV antigenemia. Although our risk-adapted pre-emptive therapy effectively reduced CMV-related mortality, further refinements of this approach, particularly in the prevention of CMV gastroenteritis, may be achieved by incorporating real-time PCR.

Adolescent↗
PubMed2000

Erythema exsudativum multiforme induced by granulocyte colony-stimulating factor in an allogeneic peripheral blood stem cell donor.

We describe a healthy peripheral blood stem cell (PBSC) donor who developed a cutaneous reaction, erythema exsudativum multiforme, during the administration of granulocyte colony-stimulating factor (G-CSF) for mobilization. The cutaneous lesions were located on his hips, apart from the site of G-CSF injection. Treatment with topical corticosteroid was commenced, and the lesions resolved completely within a week. Adverse cutaneous reactions induced by G-CSF have been reported infrequently in healthy donors. Further documentation of cases and their full evaluation will be of great importance for both physicians and PBSC donor.

Adrenal Cortex Hormones↗
PubMed2000

Changes in Helicobacter pylori-induced gastritis in the antrum and corpus during long-term acid-suppressive treatment in Japan.

BACKGROUND: Several studies have shown that acid-suppressive therapy aggravates corpus gastritis in patients with Helicobacter pylori infection, promoting the development of atrophic gastritis. AIM: To study the effects of long-term use of antisecretory agents on the H. pylori-positive gastric mucosa in Japan, a country with a high incidence of gastric cancer. METHODS: A total of 141 H. pylori-positive patients who had peptic ulcers or reflux oesophagitis were treated for 3 years with either omeprazole (20 mg/day) alone (n=7) or with omeprazole for primary therapy (8 weeks), followed by famotidine (40 mg/day) for maintenance therapy (n=134). Endoscopy was performed before, during, and after treatment. Biopsy specimens were taken from the greater curvature of the antrum and corpus and were examined histologically. RESULTS: The long-term use of famotidine after 8 weeks of treatment with omeprazole distinctly decreased H. pylori density and neutrophil infiltration in the antrum, but did not change H. pylori density in the corpus. The gastritis score increased in patients who had no, or only mild corpus gastritis before treatment (n=74), and significantly decreased in those who had moderate or severe gastritis before treatment (n=60). In four of the seven patients who received long-term treatment with omeprazole alone, neutrophil infiltration and H. pylori density decreased not only in the antrum but also in the corpus. There was no increase in intestinal metaplasia or mucosal atrophy as assessed endoscopically during follow-up. CONCLUSION: Changes in corpus gastritis in response to acid-suppressive therapy depend on the severity of gastritis before treatment. Long-term use of acid-suppressive therapy apparently does not accelerate the development of atrophy or intestinal metaplasia in Japanese patients.

Anti-Ulcer Agents↗
PubMed2000

Effect of age and Helicobacter pylori infection on gastric acid secretion.

BACKGROUND: Whether gastric acid secretion decreases with age is still controversial. With the discovery of Helicobacter pylori, the association of this bacterium with gastric acid secretion has also been discussed. The aim of this study was to investigate the relationship between gastric acid secretion, age and H. pylori infection. METHODS: The presence of H. pylori infection, the grade of fundic atrophic gastritis (FAG), and gastric acid secretion were investigated in 280 subjects without localized lesions in the upper gastrointestinal tract. Helicobacter pylori infection was confirmed by Giemsa and immunohistochemical staining, and FAG of biopsy specimens was graded on a scale of 0-4. RESULTS: Both basal and maximal acid output decreased with age in H. pylori-positive subjects, while they did not change with age in H. pylori-negative subjects. Gastric acid secretion decreased with the progression of FAG. An age-correlated decrease in gastric acid secretion in H. pylori-positive subjects depended on an increasing prevalence of FAG with age. CONCLUSIONS: In the population studied, advancing age had no influence on gastric acid secretion in H. pylori-negative subjects. Gastric acid secretion decreases with age in H. pylori-positive subjects because of the increasing prevalence of FAG with age.

Adolescent↗
PubMed2000

Synovial sarcomas of three children in the first decade: clinicopathological and molecular findings.

Synovial sarcoma in children below the age of 10 years is rare. We report on three cases of synovial sarcoma which were diagnosed in three children aged 3, 8 and 8 years, respectively. These tumors were located in the hip of the 8-year-old, the foot of the 3-year-old, and the elbow of the other 8-year-old. Histologically, one tumor was a biphasic synovial sarcoma, and the other two, which had been initially diagnosed as infantile fibrosarcoma, were of the monophasic fibrous type. In the three cases, a reverse transcription-polymerase chain reaction (RT-PCR) using ribonucleic acid extracted from formalin-fixed, paraffin-embedded tissues detected SYT-SSX1 fusion gene transcripts resulting from translocation t(X;18)(p11.2;q11.2), which is specific for synovial sarcoma. ETV6-NTRK3 fusion gene transcripts that result from t(12;15)(p13;q25), which is characteristic of congenital/infantile fibrosarcoma, were not demonstrated. In conclusion, other pediatric soft tissue sarcomas, such as congenital/infantile fibrosarcoma, spindle cell rhabdomyosarcoma, leiomyosarcoma and malignant peripheral nerve sheath tumor, should be distinguished from synovial sarcoma in children, especially the monophasic fibrous type. RT-PCR analysis is a useful approach to the final diagnosis of synovial sarcoma arising at such an early age.

Base Sequence↗
PubMed2000

Suppressive effect of saprogrelate hydrochloride on Raynaud's phenomenon and respiratory failure in patients with systemic sclerosis.

OBJECTIVE: In seven patients with systemic sclerosis (SS), we evaluated the clinical effectiveness of oral administration of saprogrelate hydrochloride (SH: 300 mg/day) for 2 months on Raynaud's phenomenon (RP) and respiratory failure estimated by Hugh-Jones classification. METHODOLOGY: We evaluated laboratory data (arterial blood gas (pH, PaO2 and PaCO2), pulmonary function tests (%VC, FEV1/FVC and %DL(CO)), mean pulmonary arterial pressure (mPAP), white blood cell count, C-reactive protein and the plasma levels of fibrinopeptide A (FPA), beta-thrombogloblin (beta-TG), platelet factor 4 (PF4) and thrombomodulin (TM)) before and after SH administration. RESULTS: The frequency and duration of RP, as well as the coldness, numbness and pain of RP were significantly decreased after SH administration (P < 0.05, P < 0.01 and P < 0.001). Respiratory failure estimated by Hugh-Jones classification was also significantly decreased after SH administration (P < 0.05), and the %DL(CO) was significantly increased (P < 0.01). The mPAP decreased significantly after SH administration (P < 0.05). Plasma FPA, beta-TG and PF4 significantly decreased after administration (P < 0.05 and P < 0.01). CONCLUSIONS: SH therapy could prevent RP and respiratory failure in patients with SS.

Adult↗
PubMed2000

Intravascular ultrasound imaging of the pulmonary arteries in primary pulmonary hypertension.

OBJECTIVE: Intravascular ultrasound has the unique ability to provide cross-sectional images of the arterial wall. This study examined intravascular ultrasound (IVUS) images of the proximal pulmonary arteries in primary pulmonary hypertension (PPH). METHODOLOGY: Study 1: Specimens from four patients who had died of PPH (in vitro PPH group) were compared with those of three patients who had died of subarachnoid haemorrhage but had no evidence of cardiopulmonary disease (in vitro control group). Three-centimetre segments of the following levels were examined by IVUS: pulmonary trunk, eight secondary branch arteries of the upper, middle, and lower lobes of both lungs, and the thoracic descending aorta. Study 2: Four patients with PPH (in vivo PPH group) and five patients without pulmonary hypertension and no evidence of cardiopulmonary disease (in vivo control group) were examined. The IVUS images of the apical segmental artery of the right upper lobe and the descending branch of the right pulmonary artery were studied. RESULTS: Echographic examination of formalin-fixed preparations of secondary branch sections of the pulmonary artery failed to show a clear three-layer structure in the in vitro control group (24 preparations), but a distinct three-layer structure and increased vessel wall thickness were observed in the in vitro PPH group (32 preparations). Similar findings were obtained in the in vivo study. The mean echo density of the proximal pulmonary arterial wall correlated well with the mean pulmonary arterial pressure (mPA) in the in vitro PPH, and also correlated with the mPA in the in vivo study (r = 0.960, P < 0.0001). The echo intensity of secondary branch sections of the pulmonary artery was higher in the in vitro PPH group than in the in vitro control group (180.5 +/- 27.0 vs 132.5 +/- 26.7 counts, P < 0.001); similar results were obtained in the in vivo study (144.7 +/- 23.4 vs 85.0 +/- 14.3 counts, P < 0.01). CONCLUSIONS: These results suggest that the histological changes detected in the pulmonary artery walls in the PPH group were responsible for the increased echo intensity.

Adult↗
PubMed2000

A new rapid test for detecting anti-Helicobacter pylori antibody excreted into urine.

BACKGROUND: Helicobacter pylori infection has been one of the most common infectious diseases in the world, whereas a gold standard for identifying its infection has not yet been established. The specific test will depend on the particular clinical, epidemiological, and scientific requirements. We recently developed a new type of rapid test to detect H. pylori antibody excreted into urine; the test requires only 20 minutes. The purpose of this study was to examine the accuracy of this rapid test. METHODS: The performance of the rapid test was compared with those of a histological search through Giemsa staining and of an assay for detecting antibodies in serum by a commercially available ELISA kit. The patients, totaling 117 (male, 62, female, 55; average age, 51.6 years), included those with peptic ulcer endoscopically diagnosed and excluded cases that were subjected to eradication therapy in the past. RESULTS: With respect to the determinations of H. pylori identified by the microscopical test and the serum antibody assay, our kit had a sensitivity of 92. 0% and a specificity of 93.1%, and the agreement of determination of H. pylori infection was as high as 91.5% and 92.3%, respectively. CONCLUSIONS: The rapid test for antibodies to H. pylori in urine could detect H. pylori infection easily, rapidly, and noninvasively and would be useful in general practice for screening patients with dyspeptic symptoms.

Antibodies, Bacterial↗