Biomedical subjects

Y Okamoto

Publications and source records attributed to Y Okamoto.

At least 253 records · Page 14Linked to original sources

PubMed1998

Changes in the proliferative activities of cells in experimental atherosclerotic plaques during remodeling.

To investigate the relationship between cytologic alterations and cellular proliferation during atherosclerotic remodeling, we examined experimental atheromatous plaques by immunohistochemistry. Plaques were formed on rabbit aortas by cholesterol-enriched diets and mechanical stimulation over a period of 2 months. Plaques were examined 1 month and 6 months after induction. We used antibodies RAM-11, HHF-35, and monoclonal anti-proliferating cell nuclear antigen (PCNA) antibody for detection of macrophages (Mphi), smooth muscle cells (SMC), and PCNA, respectively. One month after induction, the plaques revealed a thickened intima with a fibrofatty histologic pattern or accumulation of foam cells. With either histologic pattern, foam cells were found to be Mphi and proliferative activity was mainly observed in Mphi. Six months after induction, calcification and organization were seen on the induced plaques, suggesting progression of remodeling. There were fewer Mphi and more SMC compared with plaques examined 1 month after induction. Proliferative activity was observed mainly in SMC. We have demonstrated that the proliferative activity of cell types changes during remodeling of atheromatous plaques. Our results suggest an important relationship between the proliferative activity of SMC and remodeling.

Animals↗

PubMed1998

Inhibition by lysophosphatidylcholine of nitric oxide production in interleukin 1 beta-stimulated vascular smooth muscle cells.

In vascular smooth muscle cells (VSMC), inflammatory cytokines such as interleukin 1 beta(IL-1 beta) stimulated nitric oxide (NO) production via the expression of an inducible type of NO synthase (iNOS). Lysophosphatidylcholine (LPC) is a major phospholipid component of atherogenic oxidized low density lipoprotein (Ox-LDL). In this study, we examined the effect of LPC on IL-1 beta-stimulated NO production in cultured. VSMC. LPC by itself did not stimulate the production of nitrite, a stable metabolite of NO, but dose-dependently inhibited IL-1 beta-stimulated nitrite production. LPC inhibited IL-1 beta-stimulated iNOS protein expression, whereas LPC did not inhibit IL-1 beta-stimulated iNOS mRNA expression. Analysis of iNOS protein degradation rate revealed that LPC had no effect on degradation rate of iNOS protein, suggesting that LPC inhibited iNOS translation. Moreover, Ox-LDL inhibited IL-1 beta-stimulated NO production by inhibiting iNOS protein expression without affecting iNOS mRNA expression. These results indicate that Ox-LDL negatively modulates IL-1 beta-induced NO production through the action of LPC, probably by blocking translation of iNOS mRNA.

Analysis of Variance↗

PubMed1998

In vitro testing of a denture cleaning method using ozone.

The purpose of this study was to compare the microbicidal effect of gaseous ozone with that of ozonated water in order to determine its usefulness as a method for disinfecting dentures. Although a large number of research studies have been done on the bactericidal effect of ozone, little is known about its microbicidal effects on oral microorganisms. Therefore, we tested the effect of ozone on three standard strains of oral microorganisms: Streptococcus mutans (strain IID 973), Staphylococcus aureus (strain 209-P), and Candida albicans (strain LAM 14322). When the gaseous ozone injection method was used, the numbers of cells of all three strains decreased to 1/10(5) at 1 min, and by 3 min they were below the detection limit. Thus, the microbicidal effect of gaseous ozone was ascertained in a short time. In contrast, when ozonated water at 1 ppm and 3 ppm was used, C. albicans decreased to 1/10. A 700 mg/h ozone production level was needed to prepare 1 ppm ozonated water, whereas 20 mg/h of ozone was required by the gaseous ozone generator. These findings indicate that direct exposure to gaseous ozone seems to be a more effective microbicide compared with ozonated water, and that gaseous ozone can be clinically useful for disinfection of dentures.

Candida albicans↗

PubMed1998

Enantioseparation of atropisomeric 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate in capillary electrophoresis by using di- and oligosaccharides as chiral selectors: di- and oligosaccharide chiral selectors in capillary electrophoresis.

Twelve different disaccharides and a series of noncyclic malto- and cello-oligosaccharides were used as chiral selectors in capillary electrophoresis (CE). Most saccharides resolved the enantiomers of atropisomeric 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (BDHP) depending on the type (alpha or beta) and position of the linkage between monosaccharides. The effect of chain length of malto- and cello-oligosaccharides on enantioseparation of BDHP was also investigated. The nature of cations in background electrolytes affected significantly the separation of BDHP enantiomers.

Carbohydrate Sequence↗

PubMed1998

[Radiation therapy for non-small cell lung cancer with postoperative intrathoracic recurrence].

We reviewed patients with intrathoracic recurrence of non-small cell lung cancer after surgery, with reference to the feasibility of radiotherapy. The series consisted of 46 patients (39 males and 7 females) treated by radiotherapy from 1982 to 1995. Histology included squamous cell carcinoma (28 patients), adenocarcinoma (17), and large cell carcinoma (1). Clinical stage by UICC classification (1987) was as follows: stage I(2 patients), stage II(1), stage IIIa(13), stage IIIb(23), and stage IV(7). Recurrences were noted in bronchial stump (18 patients) and surgical scar (4). Metastases occurred in hilar-mediastinal lymphnodes (15), lung fields (7), and pleuropericardium (2). The mean interval from surgery to recurrence was 27 months. Delivered dose ranged from 45 to 80 Gy, and 19 patients received combined chemotherapy. Therapeutic results were as follows: complete response in 16 patients, partial response in 27, no response in 12 and progressive disease in 1, Overall 2- and 5-year survival rates were 17% and 11%, respectively, and 10 months in MST. On univariate analysis, significant prognostic factors were sex, stage at recurrence, recurrence pattern, performance status and initial response to radiotherapy, while multivariate analysis showed sex and initial response. From these data, we are encouraged by effective radiotherapy for postoperative intrathoracic recurrence of non-small cell lung cancer, especially in patients with stump or lymphnode recurrence.

Adenocarcinoma↗

PubMed1998

[The effects of midazolam on the memory of pain].

The purpose of this study was to evaluate the effects of low dose midazolam (MZ) on memories of spinal puncture. The low doses of MZ were administered to 70 patients (ASA 1-2), of whom 37 patients were premedicated with atropine sulfate 0.5 mg and pethidine hydrochloride i.m. (group P), and 33 patients received no premedication (group N). Double blind randomized trials were conducted with the doses of MZ (0, 0.03, 0.06 mg.kg-1), and MZ was administered i.v. to the patients just prior to spinal puncture. Subjective evaluation of pain was performed with pain score (PS) on postoperative phase, and objective evaluation of pain was performed with the reaction of spinal puncture. Short term memory was impaired mainly after administration of MZ. However, subjective memory of pain almost disappeared, but objective evaluation was not so good. We conclude that MZ induces impairment to recall of pain. However, it might maintain the response to the pain.

Adjuvants, Anesthesia↗

PubMed1998

[Results of radiation therapy for limited small-cell lung cancer].

Results of radiotherapy were reviewed in 68 patients with limited small-cell lung cancer from the aspect of local control. Thirty-one patients achieved CR (46%), while the other 31 remained at PR. The 1-, 2-, 3-, and 5-year cumulative survival rates were 57%, 28%, 21%, and 16%, respectively, for 15 months in MST. Thirty-six patients developed local recurrence (53%) and 46 had distant metastasis (68%). The thirty-one patients with CR had a 43% 2-year-survival rate and 23 months in MST. The remaining 37 patients (PR + NC) had respective figures of 13% and 13 months (p < 0.025). There was no statistically significant difference between radiation dose and local thoracic failure among the patients. Of the 31 patients with CR, 28 had achieved CR at 45Gy (17 received 55Gy or more, and 11 less than 55Gy). In the former, the local control rate, 2-year-survival and MST were 94%, 53% and 44 months, while in the latter these were 45%, 27% and 17 months, respectively. Thirty-five patients were irradiated by the shrinking field technique according to tumor reduction; however, this technique did not influence the treatment results. To obtain better results, it is first necessary to achieve CR at initial chemo-radiotherapy. As to irradiation, randomized trials between 50Gy and 60Gy would require patients with CR at 45Gy.

Aged↗

PubMed1998

Respiratory syncytial virus-induced interleukin-4 production by human conjunctival epithelial cells contributes to allergy: preliminary study.

PURPOSE: We previously reported allergic conjunctivitis was associated with a local pattern of cytokines and identified respiratory syncytial virus (RSV) in the conjunctival epithelium, in patients with allergic conjunctivitis. We hypothesized that RSV infected the normal conjunctival epithelium and produced interleukin-4 (IL-4), causing an allergic reaction. To determine this event, we studied production of IL-4 by human conjunctival epithelial cells, after infection with RSV. METHODS: Conjunctival samples were collected with a special brush and were challenged with 5 x 10(6) pfu/ml of live RSV. RSV infection was detected by immunocytochemical study and RT-PCR. HLA-DR antigen was expressed by flow cytometry. IL-4 was assayed by a sandwich ELISA. RESULTS: Immunocytochemical study and RT-PCR showed that RSV infected the conjunctival epithelial cells. HLA-DR was demonstrated in the RSV-infected conjunctival epithelial cells. Average concentrations of IL-4 in culture supernatants in infected cells were 3.8 +/- 1.8, 3.6 +/- 1.1, and 5.4 +/- 1.8 pg/ml at 24, 48, and 72 h, respectively. Levels in non-infected cells were 0.33 +/- 0.0, 0.59 +/- 0.69, and 0.4 +/- 0.22 pg/ml, respectively (p > 0.001). CONCLUSION: Findings suggest that the expression of IL-4 is associated with intracellular infection by RSV in conjunctiva. With our former reports, RSV infection in conjunctival epithelial cells can be suggested as one of the possible environmental pathogens of allergic conjunctivitis.

Adolescent↗

PubMed1998

[Report of four cases of lymphocytic infundibuloneurohypophysitis].

We reported 4 cases of lymphocytic infundibuloneurohypophysitis. All four patients had diabetes insipidus as initial symptoms without anterior pituitary dysfunction. All patients showed pituitary stalk swelling and two patients showed enlargement of the pituitary gland. No patients were operated on for a histological diagnosis. No patients received corticosteroid treatment for this pathology. The mean follow-up period was 36 months. The diabetes insipidus continued in all cases, but radiological findings showed improvement in all cases. In one case, adrenal insufficiency occurred after 10 months, but had disappeared 6 months later. We think lymphocytic infundibuloneurohypophysitis can be diagnosed without histological examinations and can be treated conservatively without corticosteroid treatment. It seems to be a self-limiting disease. This disease can be distinguished from lymphocytic adenohypophysitis, but in some cases, both the anterior and posterior pituitary glands are invaded, and in this situation lymphocytic hypophysitis may be an appropriate name. Even if the initial symptom is diabetes insipidus, careful follow-up is needed for the duration of the disease.

Aged↗

PubMed1998

Factors affecting postoperative prognosis in the solitary-nodule type of hepatocellular carcinoma: experience of 132 cases in our institute.

A retrospective analysis of clinical and pathological factors was performed on 132 surgical cases with solitary-nodule type HCC in our hospital. The overall cancer-free survival rates after 1, 3 and 5 years were 82.2%, 42.3% and 26.5%, respectively. With univariate analysis, the significant prognostic factors for survival were tumor size, cancer cell infiltration of the fibrous capsule of the tumor (fc-inf), invasion into portal vein (vp), and intrahepatic metastasis (im), while significant prognostic factors for non-recurrence were tumor size, fc-inf, vp, im, Edmondson-Steiner's classification and perioperative blood transfusion. With multivariate analysis for recurrence, significant factors were vp, clinical stage (CS), and perioperative blood transfusion. Therefore, prognostic factors for long-term survival in surgical cases of HCC are thought to be good hepatic function, absence of portal invasion, and avoidance of perioperative blood transfusion if possible.

Adult↗

PubMed1998

Indications for palliative reduction surgery for hepatocellular carcinoma with multiple intrahepatic metastases.

We evaluated the efficacy of and the indications for palliative reduction surgery as a procedure to improve the prognosis of hepatocellular carcinoma (HCC) patients with multiple intrahepatic metastases. From January 1986 to October 1997, 25 HCC patients with multiple intrahepatic metastases who underwent necessary palliative reduction surgery due to advanced disease, were participated in the study. The 1-, 3-, 5-year survival rates of 25 patients with reduction surgery were 54.7%, 29.9%, 22.4%, respectively. Moreover, the 1-, 3-, 5-year survival rates of patients with some postoperative supplemental treatment were 68.8%, 41.2% and 30.9%, respectively. All 6 patients who had been alive for more than 3 years had had primary tumors with diametric sizes of approximately 5 cm and had undergone, at most, one segmentectomy. These patients received postoperative supplemental treatments. The indication for palliative reduction surgery for HCC patients with multiple intrahepatic metastases was patients with a relatively small primary tumor (around 5 cm) which could be removed by one segmentectomy or less.

Aged↗

PubMed1998

Thoracoscopic microwave coagulation therapy for hepatocellular carcinoma.

Thoracoscopic microwave coagulation therapy (MCT) is a new therapeutic approach for hepatocellular carcinoma (HCC) in segments VII and VIII, which allows minimal access to the tumor and complete tumor ablation. In this study, four patients with HCC in segments VII and VIII underwent thoracoscopic MCT as a less invasive therapeutic option due to advanced liver cirrhosis and/or severe complications. Tumor sizes ranged from 15 to 30 mm in diameter and the tumors were well differentiated in 2 patients, moderately in one and poorly in one patient. Microwave irradiation was performed at an 80 W output with a 60-sec duration via a thoracoscopic route and the total duration ranged from 4 to 24 min (mean: 17 min). Patients recovered rapidly to preoperative conditions and no mortality was occurred. Complications were observed in one patient, including pleural effusion and fever elevation, but were cured conservatively. Postoperative computed tomography (CT) showed complete tumor ablation with a cancer-free margin, which is thought to be equivalent to a limited hepatic resection. This preliminary study suggests that thoracoscopic MCT might be a new, less invasive option providing a cure for HCC in segments VII and VIII in patients with advanced liver cirrhosis and severe complications.

Aged↗

PubMed1998

[Bioelectrical impedance analysis of body composition in patients with pulmonary emphysema].

In this study we utilized bioelectrical impedance analysis (BIA) to compare the body composition of 36 stable pulmonary emphysema (PE) patients with 19 healthy controls. We compared the PE patients and healthy controls in terms of fat-free mass (FFM) and body fat (BF) as percentages of ideal body weight (FFM/IBW, BF/IBW). FFM/IBW and BF/IBW were significantly lower in the PE patients than in the controls (75.0 +/- 9.8% vs. 85.2 +/- 7.3%, p < 0.001 and 11.8 +/- 6.4% vs. 16.7 +/- 7.7%, p < 0.05, respectively). We divided the PE patients into two subgroups according to FFM, then investigated the relationships between FFM and skeletal muscle strength, and between FFM and respiratory muscle strength. In patients with reduced FFM (FFM < 43.5 kg) grip strength as an index of skeletal muscle strength was significantly lower than in patients without reduced FFM (FFM > or = 43.5 kg) (25.7 +/- 7.8 kg vs. 36.2 +/- 7.2 kg, p < 0.005). As indexes of respiratory muscle strength, maximal expiratory pressure (PEmax) and maximal inspiratory pressure (PImax) were lower in the patients with reduced of FFM, but not to a statistically significant degree (49.6 +/- 20.8 cm H2O vs. 58.7 +/- 23.9 cm H2O and 40.5 +/- 19.2 cm H2O vs. 50.2 +/- 22.1 cm H2O, respectively). In the PE patients, FFM correlated closely with vital capacity (r = 0.528, p < 0.001), forced vital capacity (FVC) (r = 0.531, p < 0.001), FEV1.0 (r = 0.554, p < 0.001), FEV1.0/FVC (r = 0.467, p < 0.005), RV/TLC (r = -0.395, p < 0.05), DLco (r = 0.770, p < 0.001), and DLco/VA (r = 0.622, p < 0.001). However no correlation was observed between BF and any of the measures of lung function. The findings of our study suggest that FFM correlates with skeletal muscle strength, respiratory muscle strength and some measures of lung function in patients with PE, and that assessments of body composition are valuable to their clinical management.

Aged↗

PubMed1998

[Surface-induced mild hypothermia anesthesia for hepatectomy in a patient with a giant hemangioma of the liver (Kasabach-Merritt syndrome)].

A 63-year-old woman presenting with thrombocytepenia and signs of intravascular coagulation (prothronbin time, 59%: FDP, 100 micrograms.ml-1) due to a giant hemangioma of the liver (Kasabach-Merritt syndrome) was scheduled for the resection of the right lobe of the liver. In order to protect the liver on occlusion of the right hepatic artery and portal vein, we induced mild hypothermia technique with vasodilation and surface cooling by convecting warming device together with hepatoprotective agents of PGE1 and ulinastatin. Severe, acute massive bleeding occurred due to the injury of the middle hepatic vein and from the resected surface of the liver. Her rectal temperature was 31.9 degrees C during massive bleeding. Her hemoglobin decreased to 3.9 g.dl-1. Total estimated blood loss was 22,000 ml. The weight of the resected liver was 2.5 kg. The maximum postoperative levels of T-Bil and GOT were 2.47 mg.dl-1 and 171 IU.l-1, respectively. The liver seemed to have been well preserved and no other complications were observed. The hemangioma was completely removed by excision of the right lobe of the liver. Subsequently, all coagulation parameters returned to normal, indicating a complete reversibility of the coagulopathy. Surface-induced mild hypothermia is a useful and valuable method for protecting the liver during severe massive bleeding.

Anesthesia, General↗

PubMed1998

Percutaneous microwave coagulation therapy for hepatocellular carcinoma.

We evaluated the efficacy of percutaneous microwave coagulation therapy (PMCT) as compared with hepatectomy in 19 patients with hepatocellular carcinoma (HCC). In 6 patients with tumors more than 3 cm in diameter, coagulation was inadequate after a single session of PMCT. Patients with multiple tumors had recurrence within 1 year. For single tumors 3 cm or less in diameter, the therapeutic effectiveness of PMCT was comparable to that of hepatectomy in cumulative survival and cancer-free survival rates. We conclude that PMCT should be used in the initial treatment of HCC only in patients with single tumors of up to 3 cm in diameter. Surgical removal is recommended for tumors of more than 3 cm in diameter.

Adult↗

PubMed1998

A surgically treated long-term survivor of hepatocellular carcinoma with tumor thrombi in the trunk of the portal vein.

Prognosis of hepatocellular carcinoma (HCC) patients with tumor thrombi (TT) in the trunk of the portal vein (PV) has been extremely poor. There have been few reports of long-term survivors with such an advanced condition. In this article, the case of a 62-year-old woman of HCC, who survived for 6 years and 9 months after an operation, with TT in the trunk of the PV is described. The patient not only had a primary tumor of 4 cm in diameter with TT but also multiple intrahepatic metastases in the bilateral lobe of the liver. A palliative lateral segmentectomy with tumor thrombectomy through the incised left first branch of the PV was performed. Moreover, an intraoperative ethanol injection for residual intrahepatic metastatic tumors was performed subsequently. Hepatic arterial infusion of anti-cancer drug with Lipiodol, intraportal continuous infusion of 5-FU and percutaneous ethanol injection therapy were performed suitably during the follow-up periods. The patient survived for 6 years and 9 months after operation and died of hepatic insufficiency with cancer. In this case a patient who suffered from HCC with TT in the trunk of the PV was successfully treated by multimodality procedures including hepatic resection with tumor thrombectomy.

Antineoplastic Agents↗

PubMed1997

Serum thrombopoietin levels in patients receiving high-dose chemotherapy with support of purified peripheral blood CD34+ cells.

In a case control study, serum levels of thrombopoietin (TPO) were determined by a sandwich ELISA in 20 patients (median age, 7 years; range, 2-56 years) with various malignancies who received high-dose chemotherapy and a stem cell rescue operation. The patients received two different transplant modalities: (a) 12 patients received purified autologous peripheral blood CD34+ cells; and (b) 8 patients received cells in the CD34(-) fraction, which still contains many CD34+ cells. No significant differences were observed between the two groups with regard to the duration required to achieve an absolute granulocyte count of >0.5 x 10(9)/liter, the duration of dependence on platelet transfusion, or the number of platelet transfusions. In both groups, the serum TPO levels were inversely correlated with the circulating platelet count. Multivariate analysis demonstrated that significant determinants of the serum TPO level included the circulating platelet count (standardized regression coefficient = -0.5179), transplantation with cells in the CD34(-) fraction (0.2414), solid tumor (0.1420), and the age of the patient (-0.1236; r2 = 0.3021; P < 0.0001). These results suggest that the mode of stem cell support (ie., the presence of accessory cells in the inoculum), age, or the type of preceding chemotherapy affects serum TPO levels after transplantation.

Adolescent↗

PubMed1997

Characteristic temperatures of folding of a small peptide.

We perform a generalized-ensemble simulation of a small peptide taking the interactions among all atoms into account. From this simulation we obtain thermodynamic quantities over a wide range of temperatures. In particular, we show that the folding of a small peptide is a multistage process associated with two characteristic temperatures, the collapse temperature Ttheta and the folding temperature T. Our results give supporting evidence for the energy landscape picture and funnel concept. These ideas were previously developed in the context of studies of simplified protein models, and here are checked in an all-atom Monte Carlo simulation.

Peptides↗