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Biomedical subjects

Y Okada

Publications and source records attributed to Y Okada.

At least 163 records · Page 9Linked to original sources
PubMed2001

Evaluation of the trifluoromethanosulfonic acid/trifluoroacetic acid/thioanisole cleavage procedure for application in solid-phase peptide synthesis.

As an extension of our investigation of peptidyl-resin linkage stability towards different cleavage procedures used in the solid-phase peptide synthesis (SPPS) technique, the present paper evaluated the trifluoromethanesulfonic acid (TFMSA)/trifluoroacetic acid (TFA)/thioanisole method, varying the type of resin (benzhydrylamine-resin, BHAR; methylbenzhydrylamine-resin, MBHAR and 4-(oxymethyl)-phenylacetamidomethyl-resin, PAMR) and peptide resin-bound residue (Gly and Phe). The vasoactive angiotensin II (AII, DRVYIHPF) and its [Gly8]-AII analogue linked to those resins used routinely in tert-butyloxycarbonyl (Boc)-SPPS chemistry were submitted comparatively to a time course study towards TFMSA/TFA cleavage. At 0 degrees C, [Gly8]-AII was completely removed from all resins in less than 6 h, but the hydrophobic Phe8 moiety-containing AII sequence was only partially cleaved (not more than 15%) from BHAR or MBHAR in this period. At 25 degrees C, [Gly8]-AII cleavage time decreased to less than 2 h irrespective of the solid support, and quantitative removal of AII from PAMR and MBHAR occurred in less than 3 h. However, about 10-15 h seemed to be necessary for cleavage of AII from BHAR, and in this extended cleavage reaction a significant increase in peptide degradation rate was observed. Regardless of the cleavage temperature used, the decreasing order of acid stability measured for resins was BHAR>MBHAR>PAMR. Collectively, these findings demonstrated the feasibility of applying TFMSA/TFA solution as a substitute for anhydrous HF at the cleavage step in Boc-SPPS methodology. Care should be taken however, as the cleavage efficacy depends on multiple factors including the resin, peptide sequence, the time and temperature of reaction.

Amino Acids↗
PubMed2001

Cloning and analysis of valerophenone synthase gene expressed specifically in lupulin gland of hop (Humulus lupulus L.).

Resin and essential oil derived from hop (Humulus lupulus L.) cones are very important compounds for beer brewing, and they specifically accumulate in the lupulin gland of hop cones. In order to identify the genes responsible for the biosynthetic pathway of these compounds and use the identified genes for hop breeding using Marker Assisted Selection and transformation techniques, genes expressed specifically in the lupulin gland were cloned and sequenced. One of them was suggested to be similar to the chalcone synthase gene from the DNA sequence. The translation product of the gene had the activity of valerophenone synthase, which catalyzes a part of the synthesis reaction of alpha-acid and beta-acid. Northern analysis showed that the valerophenone synthase gene seemed to be expressed specifically in the lupulin gland.

Acyltransferases↗
PubMed2001

Changes in the tissue and plasma superoxide dismutase (SOD) levels in a burned rat model.

To examine whether thermal injury alters the superoxide dismutase (SOD) concentrations in various types of tissue or plasma, we studied the plasma and tissue Mn- and Cu/Zn-SOD levels in a rodent burn model. The animals were resuscitated with saline (50 mg/kg, i.p.) immediately following thermal injury and thereafter were sacrificed at either 6 or 24 hours post-burn. The Mn- and Cu/Zn-SOD levels were measured using an enzyme-linked immunosorbent assay (ELISA). The plasma Mn- and Cu/Zn-SOD concentrations significantly increased 6 hours after the injury and positively correlated with the burn size. The kidney Mn-SOD concentrations were significantly higher 24 hours after the injury in the animals with 30% burns than in those with either sham or 50% burn injuries. The lung Cu/Zn-SOD concentrations were also significantly higher 6 hours after the injury in animals with 30% burns than in the other two types above. These findings suggest that the changes in the SOD concentrations after burn injury vary according to the type of SOD and also the type of tissue. As a result, the SOD concentrations may play some role in the early response to thermal trauma.

Animals↗
PubMed2001

Analysis of plasma nitrite/nitrate in human thermal injury.

The aim of this study is to examine the characteristics of nitrite/nitrate (NOx), the final metabolite of nitric oxides, in plasma after burn injury. A total of 83 blood samples were collected from 19 patients on arrival, day 1, day 3, and day 5 after suffering burn injuries and from 7 non-burned volunteers. We measured the NOx levels in plasma using the Griess method, and analyzed the relationships among plasma the NOx levels, the burn-magnitude, and the blood examination data using a stepwise multivariate regression analysis. The plasma NOx levels at hospital-arrival after burns significantly exceeded those of non-burned volunteers, and the NOx levels in the plasma returned to normal range after day 1. Based on the findings of a multivariate analysis, the plasma NOx levels at admission to the hospital were not found to be related to the total burn surface area, the burn index or inhalation injury, but they were significantly related to age. Furthermore, these plasma NOx levels were also related to the platelet count, neutrophil count and blood urea nitrogen. The increase in the plasma NOx level may therefore play an important role in the pathophysiology of elderly burned patients, while the nitric oxide levels in the plasma might also play a role in inhibiting the constriction of microvascular smooth muscle in extensively burned patients.

Adult↗
PubMed2001

Relationship between stroke and asymptomatic minute hemorrhages in hypertensive patients.

Asymptomatic small hemorrhages were identified in hypertensive patients by T2*-weighted gradient echo magnetic resonance (MR) imaging to investigate the relationship between hypertensive intracerebral hemorrhage and asymptomatic minute hemorrhages. Forty-eight patients with hypertensive intracerebral hemorrhage or cerebral infarction with hypertension (these diseases were defined as stroke) were treated in National Defense Medical College from April 1998 to February 2000. All patients had no past history of stroke or head injury, underwent MR imaging within 6 months of the stroke attack, were aged from 40 to 80 years, and had no diagnosis of aneurysm, angioma, or moyamoya disease. Patients were divided into the infarction group and hemorrhage group. All foci over 2 mm in size appearing as hypointense on T2*-weighted MR imaging and unrelated to stroke areas were defined as minute hemorrhages. There were no significant differences between the two groups with respect to sex, age, and history of diabetes mellitus. The incidence of minute hemorrhages in the hemorrhage group (21/26) was greater than in the infarction group (9/22, p < 0.01). The incidence of minute hemorrhages in the basal ganglia (18/26) was greater in the hemorrhage group than in the infarction group (4/22, p < 0.001). Symptomatic intracerebral hemorrhage may be preceded by asymptomatic minute hemorrhage.

Adult↗
PubMed2001

Involvement of fluctuating high blood pressure in the enlargement of spontaneous intracerebral hematoma.

The correlations between changes in blood pressure after admission and hematoma expansion were investigated in 118 patients with spontaneous intracerebral hematoma admitted within 24 hours of onset who underwent serial computed tomography. Multiple logistic regression was performed to assess correlations between hematoma enlargement and clinical characteristics on admission. Hematoma enlargement was predominantly correlated with time of onset (p = 0.01567), and not well correlated with blood pressure at admission (p = 0.07908). Serial changes in blood pressure were investigated in 57 patients admitted within 6 hours of ictus whose blood pressures were monitored every hour from admission. Wilcoxon signed-rank analysis was used to determine the relationships between hematoma enlargement and blood pressure. Patients with hematoma enlargement was significantly correlated with increased blood pressure (p = 0.0004). Increases in blood pressure after admission may be a factor in hematoma enlargement.

Aged↗
PubMed2001

Roles of membrane type 1 matrix metalloproteinase and tissue inhibitor of metalloproteinases 2 in invasion and dissemination of human malignant glioma.

OBJECT: Acquisition of invasive and metastatic potentials through proteinase expression is an essential event in tumor progression. Among proteinases, matrix metalloproteinases (MMPs) are thought to play a key role in tumor progression through the degradation of the extracellular matrix. In the present study, the authors examined the role of MMP-2 (gelatinase A) and membrane type 1 MMP (MT1-MMP), an activator of the zymogen of MMP-2, proMMP-2, together with tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in the invasion of astrocytic tumors in humans. METHODS: Analyses performed using sandwich enzyme immunoassays demonstrated that the production levels of pro-MMP-2 and TIMP-1, but not TIMP-2, are significantly higher in glioblastomas multiforme than in other grades of astrocytic tumors. Quantitative reverse transcription-polymerase chain reaction indicated that MT1-MMP is expressed predominantly in glioblastoma tissues, and its expression levels are significantly enhanced as tumor grade increases. In addition, the expression levels and proMMP-2 activation ratio were remarkably higher in glioblastomas associated with cerebrospinal fluid (CSF) dissemination than in those not associated with CSF dissemination. In contrast, an examination of TIMP-2 levels showed a reverse correlation. Like MT1-MMP, TIMP-1 and TIMP-2 were immunolocalized to neoplastic cells in glioblastoma samples. To study the roles of these molecules in the invasion of astrocytic tumors more fully, stable transfectants expressing the MT1-MMP gene were developed in a U251 human glioblastoma cell line. The MT1-MMP transfectants displayed prominent activation of proMMP-2 and invasive growth in three-dimensional collagen gel; however, mock transfectants and parental cells displayed noninvasive growth without the activation. The invasion and gelatinolytic activity of the transfectants were completely inhibited by addition of recombinant TIMP-2, but not recombinant TIMP-1. CONCLUSIONS: These results indicate that MT1-MMP may contribute to tumor invasion and CSF dissemination of glioblastoma cells on the basis of an imbalance of TIMP-2.

Astrocytoma↗
PubMed2001

Cancer chemoprevention by ginseng in mouse liver and other organs.

Oral administration of red ginseng extracts (1% in diet for 40 weeks) resulted in the significant suppression of spontaneous liver tumor formation in C3H/He male mice. Average number of tumors per mouse in control group was 1.06, while that in red ginseng extracts-treated group was 0.33 (p<0.05). Incidence of liver tumor development was also lower in red ginseng extracts-treated group, although the difference from control group was not statistically significant. Anti-carcinogenic activity of white ginseng extracts, besides red ginseng extracts, was also investigated. In the present study, the administration of white ginseng extracts was proven to suppress tumor promoter-induced phenomena in vitro and in vivo. It is of interest that oral administration of the extracts of Ren-Shen-Yang- Rong-Tang, a white ginseng-containing Chinese medicinal prescription, resulted in the suppression of skin tumor promotion by 12-o-tetradecanoylphorbol-13-acetate in 7,12-dimethylbenz[a]anthracene-initiated CD-1 mice. These results suggest the usefulness of ginseng in the field of cancer prevention.

Animals↗
PubMed2001

[Evaluation of the process of recovery of dental pulp after Le Fort I osteotomy].

Le Fort I osteotomy has been established by many studies and is generally used, but hypoesthesia of the dental pulp, the most common complication, occurs in almost all patients. As such, we examined dental pulp sensibility, pulpal blood flow, and histological changes, to elucidate the process of functional recovery of dental pulp after Le Fort I osteotomy. Monkeys (Macaca fusucata) were used in this study. The animals underwent Le Fort I osteotomy in their unilateral maxillae. Histological and angiographic examinations were performed to observe the postoperative changes in the maxillae and dental pulp. Postoperative pulpal blood flow was examined using a laser Doppler flowmetry. Postoperative pulpal blood flow, by a laser Doppler flowmetry, and dental pulp sensibility, by electrodiagnostics, in patients who underwent Le Fort I osteotomy, were also examined. Although nerve fibers observed in the dental pulp of the maxilla degenerated and disappeared by one week postoperatively, they reappeared sparsely from two to three months after osteotomy, and there were abundant nerve fibers by one year postoperatively. In the angiographic examination, blood supply to the maxillary dental pulp was maintained throughout the postoperative period. In the examinations of laser Doppler flowmetry and dental pulp electrodiagnostics, ischemia in the dental pulp for three or four days after osteotomy might delay the recovery of dental pulp sensibility. These results suggested that blood flow in dental pulp at three or four days after surgery may affect the recovery of dental pulp sensibility.

Animals↗
PubMed2001

[Systemic lupus erythematosus presenting as a brainstem infarction and hemorrhage during treating retroperitoneal abscess: a case report].

We report a case of a brainstem infarction and hemorrhage seen in a 21-year-old female with systemic lupus erythematosus (SLE) during treating retroperitoneal abscess. SLE has been treated with prednisolone and mizoribine for 4 years. The patient with right back and lower abdominal pain visited our hospital. Computed tomography (CT) revealed retroperitoneal abscess over surrounding right kidney, horizontal part of duodenum and in front of psoas muscle. Drainage was done with indwelled right single J catheter and penrose drain. Retroperitoneal abscess was much smaller, but, post drainage day 17, high fever, unconsciousness, down-blood pressure and down-beat nystagmus appeared suddenly. Brain CT scan revealed a brainstem wide infarction and hemorrhage spot. Pulse therapy with steroid was done, however unfortunately the patient was dead after 6 days.

Adult↗
PubMed2001

Saccharin activates cation conductance via inositol 1,4,5-trisphosphate production in a subset of isolated rod taste cells in the frog.

The transduction mechanism of the conductance activated by saccharin was analysed in isolated bullfrog taste cells under whole-cell voltage-clamp. Bath application of 30 mM saccharin induced an inward current of -34 +/- 12 pA (mean +/- SEM, n = 10) at a membrane potential of -50 mV in 10 (23%) of 44 rod cells. The concentration-response relationship for the saccharin-gated current was consistent with that of the gustatory neural response. The saccharin-induced current was accompanied with a conductance increase under internal low Cl- condition (E(Cl) = -56 mV), suggesting that saccharin activated a cation conductance. The reversal potential of the saccharin-induced current was -17 +/- 2 mV (n = 10). Intracellular dialysis of 0.5 mM guanosine 5'-O-(2-thiodiphosphate) (GDP-beta-S) completely blocked the saccharin-induced response, suggesting the involvement of a G protein in the transduction. The dialysis of heparin (1 mg/mL) also inhibited the response almost completely, but the dialysis of 1 mM 8-Br-cAMP did not affect the response significantly. Intracellular 50 microM inositol 1,4,5-trisphosphate (1,4,5 InsP(3)) also induced the inward current in five (38%) of 13 rod cells, but intracellular Pasteurella multocida toxin (5 microg/mL, G alpha q-coupled PLC activator) did not elicit any response in the cells. The results suggest that saccharin mainly activates a cation conductance in frog taste cells through the mediation of IP3 production.

Animals↗
PubMed2001

[New approaches for excellent operative field during tracheobronchial anastomoses in sleeve pneumonectomy: cardiopulmonary bypass and diseased lung ventilation].

Cardiopulmonary bypass (CPB) and diseased lung ventilation were presented as new methods of oxygenation during carinal reconstruction. Two cases of left sleeve pneumonectomy (SP) were performed for bronchial gland carcinoma through clamshell incisions. Adequate oxygenation and excellent operative fields were provided by CPB in both patients. The postoperative courses of these patients were uneventful, although they developed temporary pulmonary edema that needed mechanical ventilation and appropriate diuretics for several days. One case of patient with squamous cell carcinoma after chemotherapy was successfully treated by right SP through midline sternotomy. Adequate oxygenation and excellent operative fields was obtained by diseased right lung ventilation in this patient. The postoperative course of the patient was uneventful without mechanical ventilation support. These procedures of oxygenation in this paper are considered to be safe and effective methods for carinal reconstruction.

Adult↗
PubMed2001

[All-trans retinoic acid combined with low-dose cytosine arabinoside treatment for acute myelogenous leukemia with trilineage myelodysplasia--a case report].

AML with trilineage myelodysplasia (AML/TMDS) is recognized as having of poor prognosis due to its resistance to chemotherapy in comparison with de novo AML. An AML/TMDS patient who failed to respond to ordinary induction therapy achieved complete remission with combination therapy consisting of all-trans retinoic acid (ATRA) and low-dose Ara-C. No serious toxicity was observed. ATRA combined with low-dose Ara-C could be an alternative treatment for this kind of patient.

Antimetabolites, Antineoplastic↗
PubMed2001

[Influence of intubation maneuver with or without premedication for intracranial hemorrhage with unconsciousness].

PURPOSE: To clarify the influence of intubation maneuver with or without premedication for intracranial hemorrhage with unconsciousness. METHODS: Between May 1995 and May 2000, we analyzed retrospectively 46 patients who had received intubation for unconsciousness and were found non-traumatic intracranial hemorrhage by head computer tomography at the Trauma and Critical Care Center, National Defense Medical College. They were divided into two groups, Drug group in which drugs were used before intubation and Control group which were intubated without drugs. Physical findings on admission, head CT findings, Glasgow Outcome Score(GOS) at discharge were analyzed between the groups. RESULTS: There were no significant differences for background of subjects between the groups. In the Drug group, diazepam, pentazocine, lidocaine, nifedipine and nicardipine were used before intubation. GOS in the Control group was significantly greater than in the Drug group(p < 0.01). CONCLUSION: In case of intubation for unconscious patients who may suffer intracranial hemorrhage, using premedication leads to favorable outcome.

Adult↗
PubMed2001

[Evaluation of efficiency of ACD-CPR and STD-CPR; a multi-institutional study].

We compared the efficacy of ACD-CPR and STD-CPR based on 64 multi-institutional reports. No significant differences were observed in the rate of restoration of spontaneous circulation (ROSC) and in cardiopulmonary parameters during CPR using the two methods. There were 5 cases in which cardiopulmonary parameters improved after switching from STD-CPR to ACD-CPR and, eventually, in two of them spontaneous circulation was restored. In the ROSC cases of both groups, ETCO2 and values of SpO2, PaO2, and systolic BP at 30 minutes were higher than those of non-ROSC cases. ETCO2 never exceeded 20 mmHg in the non-ROSC cases, but it was higher in the ROSC cases. ACD-CPR is a good choice when trained persons are present or when extra hands are available to continue the CPR.

Adolescent↗
PubMed2001

Expression patterns of cancer testis antigens in testicular germ cell tumors and adjacent testicular tissue.

PURPOSE: The human cancer-testis antigens (CTAs) are a group of tumor specific antigens recognized by cytotoxic T lymphocytes whose expression occurs in human malignancies as well as in normal testicular tissue. We studied a series of CTA gene transcripts in testicular germ cell tumors of various histological types to test the hypothesis that the expression of CTA in testicular germ cell tumors reflects developmental stages of tumorigenesis rather than constitutive tumor antigens recognized by cytotoxic T lymphocytes. MATERIALS AND METHODS: Total RNA was obtained from 31 primary and 3 metastatic testicular germ cell tumors, and 11 parenchymal tissues adjacent to the testicular germ cell tumors. We performed an expression study of the CTA genes MAGE-A, MAGE-B, GAGE, PAGE-1, HOM-MEL-40 (SSX2), NY-ESO-1, LAGE-1 and SCP-1 in these samples using reverse transcriptase-polymerase chain reaction. RESULTS: The results showed that expression patterns of CTA genes depended on the histological differentiation of the testicular germ cell tumors. Overall CTA expression was more common in seminomas than in nonseminomatous germ cell tumors. Specifically all 13 seminomas (100%) demonstrated the positive expression of MAGE-B1 and MAGE-B2, while 3 of 17 nonseminomatous germ cell tumor samples (18%) showed positive expression of these genes. All 5 teratomatous elements (100%) had homogenous null expression with regard to all CTA genes examined. In addition, we detected deficiencies in CTA expression in 7 of 11 parenchymal tissues adjacent to the testicular germ cell tumors (64%). CONCLUSIONS: These data support the idea that CTA transcripts in testicular germ cell tumors serve as developmental footprints of testicular germ cell tumors rather than as constitutive tumor antigens recognized by cytotoxic T lymphocytes.

Antigens, Neoplasm↗