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Biomedical subjects

K Okamoto

Publications and source records attributed to K Okamoto.

At least 451 records · Page 25Linked to original sources
PubMed1997

Pretreatment virus load and multiple amino acid substitutions in the interferon sensitivity-determining region predict the outcome of interferon treatment in patients with chronic genotype 1b hepatitis C virus infection.

Hepatitis C virus (HCV) genotype 1b and high pretreatment virus load are predictive factors of poor response to interferon therapy in patients with chronic hepatitis C. To further examine the factors predicting the response to interferon in patients with genotype 1b infection, we analyzed 110 consecutive patients with HCV who were treated with a total of 624 million units of lymphoblastoid interferon alfa. Thirty-six patients (33%) were responders, while the remaining 74 patients (67%) were nonresponders. Multivariate analysis showed that a high virus titer (assessed by serum core protein level, P = .0021) and the presence of more than two amino acid substitutions in the interferon sensitivity-determining region (ISDR) (P = .0036) correlated significantly with the response to interferon therapy. Because mutations analyzed by direct sequencing of polymerase chain reaction (PCR) products may reflect artifacts of direct sequencing, we further analyzed quasispecies of HCV in this region by cloning and sequencing. Although PCR-based analysis of responders with multiple amino acid substitutions in the ISDR showed the presence of a small amount of wild-type strain in their serum, the results obtained by direct sequencing and cloning were essentially the same. A longitudinal study of quasispecies in 2 patients who showed a dramatic change in the virus titer showed no conversion from wild type to mutant or vice versa. Our results indicate that amino acid substitutions and virus load are independent predictors of the response to interferon therapy. The ability of some patients with no mutation in the ISDR or high virus load to eliminate the virus suggests the presence of other unidentified factors, host or viral, that influence the response to interferon therapy.

Adult↗
PubMed1997

Indications and problems of coronary artery bypass grafting without cardiopulmonary bypass.

As an alternative method of myocardial protection and to obviate the inherent risks of cardiopulmonary bypass (CPB), we have been performing coronary artery bypass grafting (CABG) without CPB in carefully selected patients. Since the first such operation was successfully performed in January 1995 on a patient with angina pectoris and lung cancer, four other patients have subsequently undergone this technique. This series of 5 patients, being 1 man and 4 women ranging in age from 68 to 80 years, is presented in this report. The reasons for the selection of this procedure were concomitant diseases including lung cancer, a calcified aorta, and myocardial infarction. The mean time of ischemia for each anastomosis was 15.3 +/- 5.3 min, and the maximum cardiac muscle creatine phosphokinase (CPK-MB) was less than 14 unit/l postoperatively. None of the patients required ventilatory support for longer than 24 h postoperatively, and oral intake was started within 24 h after extubation in all patients. Postoperative angiography confirmed graft patency and none of the patients developed any ischemic symptoms. All the patients were discharged between 1 and 2 months postoperatively. Thus, the off-pump technique is useful when concomitant diseases are present and will become an alternative method of treatment for coronary artery disease in selected patients.

Aged↗
PubMed1997

Right ventricular myxoma: report of a case.

We herein report a 36-year-old man who underwent surgical resection for myxoma. Preoperative two-dimensional echocardiography demonstrated a mass in the right ventricle. Intraoperatively, the tumor was found to derive from an anterior papillary muscle of the tricuspid valve. The tumor was successfully excised and the tricuspid valve was repaired with chordoplasty and annuloplasty. A histopathological examination revealed myxoma and a 2-year follow-up has shown no evidence of recurrence or tricuspid valve regurgitation.

Adult↗
PubMed1997

Primary malignant fibrous histiocytoma of the descending colon.

We herein present the case of a 50-year-old woman with malignant fibrous histiocytoma arising from the descending colon and localizing in the colonic wall. Malignant fibrous histiocytoma of the large bowel is a very rare tumor. A total of 18 cases, including our case, have been reported in the world medical literature so far and we also reviewed these cases. In our case, combined adjuvant chemotherapy was administered after a complete resection had been performed. No clinical signs of local recurrence or distant metastasis were found at 7 years after the operation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

The operative indications for proximal gastrectomy in patients with gastric cancer in the upper third of the stomach.

While proximal gastrectomy is often performed for early gastric cancer in Japan, it remains unclear whether or not proximal gastrectomy should be performed for advanced gastric cancer. This study was designed to determine the operative indications for proximal gastrectomy in patients with gastric cancer in the upper third of the stomach. A total of 1691 patients with gastric cancer were reviewed retrospectively from hospital records during the period from 1969 to 1994, and the clinicopathologic characteristics of 82 patients who underwent proximal gastrectomy were compared with those of 150 patients who underwent total gastrectomy. Lymph node metastasis along the lower part of the stomach was observed in gastric cancers which had invaded beyond the muscularis propria of the stomach, but not in those confined to the muscularis propria. Three patients with gastric cancer that had invaded beyond the muscularis propria and metastasized to nodes along the lower part of the stomach were cured by total gastrectomy. However, there was no difference in the postoperative survival rates of the patients treated with proximal gastrectomy and those treated with total gastrectomy, irrespective of tumor stage and depth of invasion. Thus, proximal gastrectomy should be performed for gastric cancer when the depth of invasion is confined to the muscularis propria of the stomach.

Aged↗
PubMed1997

Solitary plasmacytomas of the occipital bone: a report of two cases.

The radiological appearances of two cases of solitary plasmacytoma in the occipital bone are described. One arose in the lateral part and the other in the squama. They showed characteristic radiological features on CT, MRI and angiography. Bone scintigraphy and gallium scintigraphy were also available. Solitary plasmacytoma of the skull is a rare condition and usually occurs in the calvarium. The skull base is an extremely rare site and only four cases have been reported. The literature of solitary plasmacytoma of the skull is reviewed.

Aged↗
PubMed1997

Enhancement of human parainfluenza virus-induced cell fusion by pradimicin, a low molecular weight mannose-binding antibiotic.

Oligosaccharides, especially mannose residues, expressed on the cell surface, are thought to be important for virus-induced membrane fusion. We examined the effect of mannose-binding compounds, pradimicin derivative BMY-28,864 (PRM) and concanavalin A (Con A), on cell fusion of human parainfluenza type 2 virus (hPIV2)-infected HeLa cells. Syncytium formation of hPIV2-infected HeLa cells was suppressed in the presence of Con A. On the other hand, PRM enhanced cell fusion of hPIV2-infected HeLa cells. These effects were blocked by addition of mannose-rich mannan. However, PRM shows little effect on virus growth and the expression of viral glycoproteins on the cell surface in hPIV2-infected HeLa cells. Fluorescein-isothiocyanate-labeled pradimicin and Con A bound to both uninfected and hPIV2-infected mononuclear cells, indicating that these compounds have an affinity to several cellular component(s). In contrast to Con A, PRM had little affinity to the viral glycoproteins. It is inferred from these results that the enhancement of hPIV2-induced cell fusion is probably due to the interaction between PRM and cellular component(s).

Anthracyclines↗
PubMed1997

Protein tyrosine kinase activation provides an early and obligatory signal in anti-FRP-1/CD98/4F2 monoclonal antibody induced cell fusion mediated by HIV gp160.

The mechanism by which anti-fusion regulatory protein-1 (FRP-1) monoclonal antibody (mAb) induced cell fusion was investigated using U2ME-7 cells that are CD4+U937 cells transfected with the HIV gp160 gene. Protein kinase inhibitors (H-7, H-89, herbimycin A and genistein) suppressed cell fusion of Cd+U2ME-7 cells induced by anti-FRP-1 mAb. H-7 and H-89 also inhibited the cell aggregation, but herbimycin A and genistein did not. Intriguingly, only when herbimycin A was added either before or simultaneously with addition of anti-FRP-1 mAb, was cell fusion suppressed, suggesting that tyrosine kinase is related with the initial step of polykaryocyte formation. Anti-FRP-1 mAb induced the rapid tyrosine phosphorylation of multiple cellular proteins. These effects occurred within 1 min and returned to near baseline by 60 min. The rapid tyrosine phosphorylation was suppressed by herbimycin A and genistein. Although it remains to be determined which protein tyrosine kinase(s) is involved in this response, pp130 tyrosine phosphorylation appears to be a specific and early signal transmitted after the interaction of FRP-1 with a specific antibody. pp130 was present in the cytosol fraction and was distinct from pp125FAK, p130CAS, vinculin, and beta 1-integrin. Thus, our study may present evidence for a novel pathway of protein tyrosine kinases that phosphorylate specific, still unknown protein substrates during polykaryocyte formation.

Antibodies, Monoclonal↗
PubMed1997

Management of giant common bile duct stones in high-risk patients using a combined transhepatic and endoscopic approach.

BACKGROUND: Endoscopic sphincterotomy (EST) for removing common bile duct stones is regarded as the safest and most successful method, particularly in patients with a high surgical risk. However, giant immobile stones still continue to present a therapeutic problem. METHODS: In our 12 patients, when endoscopic sphincterotomy and lithotomy proved to be unsuccessful a transhepatic choledochoscopic lithotomy was attempted. RESULTS: The stones were fragmented using choledochoscopic electrohydraulic lithotripsy and then were completely removed through both the transhepatic route and an EST opening in all 12 patients. The number of sessions required for these choledochoscopic procedures combined with EST was fewer than that required for only a transhepatic approach (2.5 +/- 1.3 versus 3.2 +/- 1.2), which thus resulted in a shorter hospital stay. Minor complications occurred in three patients with bleeding (two from the bile duct, one from the EST opening) and in two with postprocedure chills and fever. CONCLUSIONS: A combined lithotomy through duodenoscopic and choledochoscopic approaches is considered to be an efficient method for removing giant biliary calculi in patients who are not successfully treated by an ordinary duodenoscopic lithotomy.

Aged↗
PubMed1997

SA4503, a novel cognitive enhancer, with sigma 1 receptor agonistic properties.

We found a potent and selective sigma 1 (sigma 1) receptor ligand, SA4503 (1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride). This compound had a high affinity for sigma 1 receptor subtype (IC50 = 17 +/- 1.9 nM), but a low affinity for sigma 2 receptor subtype (IC50 = 1800 +/- 310 nM). The present study examines the effect of this compound on the central cholinergic functions, since sigma receptor has been reported to interact with the central cholinergic neurons. SA4503 elicited the increase in extracellular acetylcholine level in rat frontal cortex, while it did not affect the striatal acetylcholine level. On the other hand, tetrahydroaminoacridine (THA), an acetylcholinesterase (AChE) inhibitor, increased the extracellular acetylcholine level in both regions. Although both compounds had anti-amnesic effect against scopolamine-induced memory impairment, THA also induced catalepsy in rats. These results suggest that SA4503 may be a novel cognitive enhancer, with sigma 1 receptor agonistic properties. In addition, SA4503 does not cause striatal cholinomimetic side-effects, which is different from THA.

Acetylcholine↗
PubMed1997

Prolonged antimicrobial effect of tissue conditioners containing silver-zeolite.

OBJECTIVES: The purpose of this study was to elucidate the in vitro antimicrobial effect of tissue conditioners containing silver-zeolite on Candida albicans and nosocomial respiratory infection-causing bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. METHODS: Five commercially available tissue conditioners were selected: Visco-gel (VG), GC Soft-Liner (SL), Fitt (FT), SR-Ivoseal (IV) and Shofu Tissue Conditioner (TC). Samples, 10 x 10 x 2.5 mm in size, contained silver-zeolite (SZ sample) and no SZ (N sample). The antimicrobial effects of these two samples were evaluated as a percentage of viable cells (CFU) in a microbial suspension (100 microliter) in phosphate-buffered saline with or without immersion in artificial saliva for four weeks. The borderline of the antimicrobial effect was determined at 0.1% viable cells. RESULTS: With the SZ samples, all tested microbes were killed under both conditions of no immersion and immersion in saliva. In non-immersed N samples, however, no cells of C. albicans (except with VG) and S. aureus survived, whereas the percentage of viable cells of P. aeruginosa was similar to that found in the control. However, with immersion in saliva, viable cells of C. albicans in some N samples (VG, SL and TC) increased compared with non-immersion samples by more than 0.1%. CONCLUSION: Tissue conditioners containing SZ have been shown to have antimicrobial effects for four weeks on C. albicans and nosocomial respiratory infection-causing bacteria in saliva in vitro.

Acrylic Resins↗
PubMed1997

Emergency extracorporeal life support for patients with near-fatal status asthmaticus.

Extracorporeal life support (ECLS) was used to treat three patients with near-fatal status asthmaticus who did not respond to aggressive medical therapies and mechanical ventilation under controlled permissive hypercapnia. ECLS was instituted in patient 1 because PaCO2 was excessively high and pH was excessively low, in patient 2 because hypoxemia and shock were not responsive to treatment, and in patient 3 because of sustained severe hypotension. ECLS supported adequate gas exchange until pulmonary function improved, diminishing the need for mechanical ventilation and preventing pulmonary complications. Pulmonary dysfunction improved markedly after only 21 to 86 hours of ECLS. Aggressive medical treatments were continued during ECLS. Our findings indicate that ECLS is a useful method for preventing death in patients with near-fatal status asthmaticus.

Adolescent↗
PubMed1997

End results of simultaneous pancreatectomy, splenectomy and total gastrectomy for patients with gastric carcinoma.

A distal pancreatectomy is often performed simultaneously with splenectomy and total gastrectomy in the treatment of gastric carcinoma to facilitate dissection of the lymph nodes around the splenic artery. However, the morbidity of partial pancreatectomy is high. Patients undergoing pancreaticosplenectomy in conjunction with total gastrectomy are subject to leaks from the pancreatic stump, which may cause further complications. We performed a retrospective analysis to evaluate the end results of simultaneous distal pancreatectomy with total gastrectomy. The effect of distal pancreatectomy on survival was studied by examination of the records of 174 patients who underwent splenectomy and total gastrectomy for gastric carcinoma. Of these, 93 underwent distal pancreatectomy. Prognostic factors were determined and were examined in relation to the post-operative complications. There was no significant difference in the 5-year survival of the patients who did or did not undergo distal pancreatectomy. There was no correlation between any prognostic factor and distal pancreatectomy. In contrast, distal pancreatectomy was independently associated with post-operative complications. In this retrospective study, the addition of distal pancreatectomy to splenectomy at total gastrectomy for patients with gastric cancer did not affect survival but was associated with severe complications.

Aged↗
PubMed1997

Early gastric cancer mimicking advanced gastric cancer.

The clinicopathological features of 37 early gastric cancers mimicking advanced gastric cancer were reviewed retrospectively, and were compared with 596 other early gastric cancers and 126 mp gastric cancers, defined as gastric cancer invading the muscularis propria of the stomach. A greater tumour size (P < 0.005), submucosal invasion (P < 0.005), lymph node and lymph vessel invasion (P < 0.005) and vascular invasion (P < 0.025) were found more frequently in early gastric cancers mimicking advanced gastric cancers than in other early gastric cancers. There were no significant differences in the clinicopathological findings between early gastric cancers mimicking advanced gastric cancers and mp gastric cancers. Patients with early gastric cancers mimicking advanced gastric cancers showed a lower survival rate than patients with other early gastric cancers, but a higher survival than those with mp gastric cancers. The macroscopic appearance of an advanced gastric cancer was an indicator of massive submucosal invasion and lymph node metastasis in early gastric cancer. As early gastric cancers mimicking advanced gastric cancers showed similar clinicopathological findings to mp gastric cancers, these cancers should be treated as mp gastric cancers.

Female↗
PubMed1997

A novel acute lymphoid leukaemia type BCR/ABL transcript in chronic myelogenous leukaemia.

Using a reverse transcription-polymerase chain reaction (RT-PCR), we identified a patient with typical clinical features of chronic myelogenous leukaemia (CML) in the chronic phase who showed no amplification of the CML-type BCR/ABL transcript. RT-PCR with primers detecting the acute lymphoid leukaemia (ALL)-type transcript disclosed a novel fragment co-amplified with an ALL-type fragment. Sequencing revealed the novel transcript to be a chimaeric mRNA produced by fusion of a segment of BCR exon 2 (e2) to ABL exon 2 (a2), with a 21 base-pair insertion of ABL intron 1b sequence between them. This transcript has not been reported previously.

Adult↗
PubMed1997

Modulation of circadian expression of D-site binding protein by the schedule of parenteral nutrition in rat liver.

The aim of this study was to investigate the changes in the circadian rhythm of the expression of liver-specific genes caused by different schedules of parenteral nutrition (PN). Rats received PN continuously throughout the day or intermittently during the night or day for 7 days. They were examined for gene expression of D-site binding protein (DBP), albumin, and cytochrome P450 cholesterol 7alpha-hydroxylase (CYP7) in the liver. The nocturnal PN group showed circadian expression of DBP messenger RNA (mRNA) and protein with a peak at 10 PM, in the same manner as the control rats receiving normal chow feeding. However, the diurnal PN group showed inverted expression of DBP mRNA and protein with a peak at 10 AM. CYP7 mRNA levels exhibited good synchronization with the levels of DBP mRNA in all groups, whereas albumin mRNA levels did not show such synchronization. Gel mobility-shift assay disclosed that the binding activity of the nuclear extracts to the CYP7 gene promoter was changed by the PN schedule in accordance with the expression of CYP7 mRNA. The PN schedule modulates the circadian rhythm of DBP expression and may have an effect on hepatic bile acid formation through transcriptional regulation of the CYP7 gene.

Albumins↗