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Biomedical subjects

T Iwai

Publications and source records attributed to T Iwai.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Complete responses in patients with unresectable liver metastases from colorectal cancer with weekly high-dose 5-FU plus one-shot CDDP HAI].

Thirty-two patients with unresectable liver metastases from colorectal cancer, treated by intermittent hepatic arterial infusion of high-dose 5-FU combined with CDDP, were assessed. As a result of this treatment, the overall response rate was 65.6%, and eight patients (25%) which contained three autopsy cases revealed a complete response. The mean doses of 5-FU and CDDP which was administered in the eight patients were 24.3 g and 65 mg, respectively. One of the eight patients showed complete disappearance of liver metastasis on the CT scan after arterial infusion of 4.5 g of 5-FU, and necrosis or disappearance of the tumor was present in more than 2/3 of the whole lesion. Autopsy showed focal or zonal necrosis, distorted reconstruction of architecture, and cholangiolitis of the liver which were administered more than 15 g of 5-FU. Intermittent hepatic arterial infusion of high-dose 5-FU combined with CDDP is proved to be a useful locoregional chemotherapy for liver metastasis from colorectal cancer. We should evolve new treatment modalities for extrahepatic metastases, as HAI combined with the systemic chemotherapeutic regimen.

Aged↗
PubMed1999

[Complications related to hepatic arterial infusion chemotherapy for liver metastasis from colorectal cancer].

UNLABELLED: We evaluated the complications of hepatic arterial infusion (HAI) chemotherapy in patients (pts) with hepatic metastasis from colorectal cancer. The subjects consisted of 61 pts with hepatic metastasis from colorectal cancer, who were treated by combined chemotherapy with 5-FU and CDDP weekly or continuously. Indwelling route of catheter: 30 via gastroduodenal artery (GDA) at the time of laparotomy ('LP'), 21 via femoral artery (FA) and catheter tip in PHA ('PHA'), 10 via FA and catheter tip is inserted with steel coil into the GDA ('GDA-coil'). Complications resulting in interruption of therapy occurred in 19 pts (31%), and the 'GDA-coil' method had a lower rate of complication than others. There was no difference in the incidence rate of complications between the two chemotherapy regimens. The complications of this therapy were: 8 (13%) cases of hepatic arterial occlusion, 3 (5%) cases of duodenal ulcer, 4 (7%) cases of catheter tip dislocation, 2 (3%) cases of catheter tip dislocation to the duodenal bulb, and 1 (2%) case of liver abscess. Hepatic arterial occlusion occurred frequently in LP. Up to 67% of patients with duodenal ulcer had hepatic arterial occlusion at the same time. All pts with catheter tip dislocation were 'PHA', and all pts with catheter tip dislocation to the duodenal bulb were 'LP'. IN CONCLUSION: 1. The best indwelling route for the catheter is by the 'GDA-coil' method. 2. To diagnose complications soon, regular CTA or DSA is necessary.

Adult↗
PubMed1998

Genomic organization and mutation analyses of the DR5/TRAIL receptor 2 gene in colorectal carcinomas.

The DR5/TRAIL receptor 2 gene is a novel TNF receptor family member and induces apoptosis by overexpression of its product. DR5 is located on chromosome 8p21, where allelic deletions are often observed in advanced colorectal cancers. This evidence led us to examine whether or not mutations of the DR5 gene exist in these tumors. We determined the genomic structure of DR5, which consists of nine exons. DR5 has two alternatively spliced isoforms. All seven colorectal cancer (CRC) cell lines examined expressed the longer isoform predominantly. No somatic mutation was found in 41 CRC cases. Loss of heterozygosity of DR5 was found in nine (52.9%) of the 17 informative cases, which is similar to the previously reported frequencies observed for 8p21-22 in colorectal cancers. These findings suggest that inactivation of the DR5 gene may play only a small role, if any, in colorectal tumorigenesis.

Apoptosis↗
PubMed1998

Frequent aberration of FHIT gene expression in acute leukemias.

We analyzed the mRNA expression of the FHIT gene by reverse transcription-PCR (RT-PCR) in 54 cases of acute lymphoblastic leukemia (ALL; 11 cases of T-cell ALL [T-ALL] and 43 cases of non-T-ALL) and 40 cases of acute myeloid leukemia (AML). In 46% of the ALL cases and 55% of the AML cases, FHIT expression was absent or markedly decreased. Only abnormal short bands were detected in 30% of the ALL cases and 5% of the AML cases. Eighteen of 19 abnormal transcripts had the same fusion of exons 2-7, and all lacked the starting codon in exon 5. No obvious normal-sized PCR products were detected in cases exhibiting abnormal transcripts. These findings suggest that the expression of functional FHIT protein was lost in the majority of ALL (76%) and AML (60%) cases. Differential quantitative PCR of exons 3-9 of the FHIT gene and RT-PCR of the PTPRG gene, which is centromeric to the FHIT gene, showed the presence of the target sequences. Fluorescence in situ hybridization analysis using probes covering exons 5 and 8 revealed no difference in the signal patterns between leukemia and normal cells, showing one or two signal doublets in more than 90% of nuclei, and indicated that gross segments of the FHIT gene were not homozygously deleted in these cases. A small number of transcripts with an aberrant fusion between exons 2 and 7 were detected by RT-PCR in the bone marrow cells from four healthy individuals. Granulocytes, lymphocytes, and monocytes in the bone marrow cells of a healthy individual contained transcripts with the same fusion. This unique fusion of exons 2 and 7 might be preferentially seen in either neoplastic or normal hematopoietic cells, regardless of their lineage. The finding that FHIT expression was abolished in the majority of leukemia cases might support the hypothesis that the FHIT gene acts as a tumor suppressor, at least in leukemia.

Acid Anhydride Hydrolases↗
PubMed1998

Buerger's disease with intestinal involvement.

Here I describe three cases of intestinal Buerger's disease and review previously reported cases. All patients had involvement of the extremities and clinical manifestations of Buerger's disease. Occlusive changes in intestinal arteries also occurred, in both the presence and absence of abdominal symptoms. Intestinal Buerger's disease may be asymptomatic, acute, or chronic, and treatment varies according to the type of disease.

Adult↗
PubMed1998

Transport of fragmented DNA in apical dendrites of gerbil CA1 pyramidal neurons following transient forebrain ischemia.

Transport of fragmented DNA in apical dendrites of the CA1 pyramidal neurons of gerbil hippocampus is observed in the apoptotic process following transient forebrain ischemia. The time-course of specific DNA fragmentation was examined after the ischemic insult by in situ nick-end-labeling method and fluorescence detection technique by DAPI. Although the role of the fragmented DNA movement is unclear, the transport mechanism of fragmented DNA is still active in the late phase of apoptotic process.

Animals↗
PubMed1998

Diastereoselective two-directional synthesis and cation transport ability of the central tristetrahydrofuranyl unit of meso polyether glabrescol as naturally occurring podand.

The diastereoselective synthesis of the central 2,5-linked tristetrahydrofuran (trisTHF) 6 of naturally occurring meso polyether, glabrescol (5), has been achieved in a two-directional manner by the vanadium(V)-catalyzed anti oxidative cyclizations of diol 14. The trisTHF podand 6 and its stereoisomeric analogs 7 and 8 exhibited outstanding cation transport abilities for physiologically important Na+ and K+.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Relationship between magnitude of hypothermia during ischemia and preventive effect against post-ischemic DNA fragmentation in the gerbil hippocampus.

Protective effect of hypothermia against DNA fragmentation in hippocampal CA1 field after transient forebrain ischemia in gerbils was evaluated by changing the magnitude of hypothermia. Inhibition of DNA fragmentation was proportional to the magnitude of hypothermia. The result indicates that, in terms of susceptibility to ischemia, hippocampal CA1 neurons are sensitive to a relatively small decrement of temperature, with temperatures </=35 degreesC being critical for the prevention of apoptotic process following transient forebrain ischemia.

Animals↗
PubMed1998

Measurement of left ventricular maximal isovolumetric pressure in rats: effects of antihypertensive drugs and diabetes mellitus.

We developed a method for measuring left ventricular maximal isovolumetric pressure (LVMIP) in intact rats and applied it in the presence of acutely administered antihypertensive drugs and in experimental diabetes mellitus. The combination of a 2 French Fogarty arterial embolectomy balloon catheter with a new ultra-thin shaft (0.25 mm diameter) Millar ultra-miniature pressure tip catheter was used. Closed-chest, thiopental anaesthetized female Sprague-Dawley rats received the beta-adrenoceptor blocker metoprolol (1 mg/kg/h), the alpha-adrenoceptor blocker prazosin (0.1 mg/kg/h), and the calcium antagonist nifedipine (0.5 mg/kg/h). They were applied as continuous i.v. infusion for 30 minutes. The angiotensin II type 1 (AT1) receptor antagonist losartan (3 mg/kg) was applied as bolus i.v. injection. Diabetes mellitus was induced by a single tail vein injection of streptozotocin (60 mg/kg) five weeks prior to hemodynamic measurements. Under control conditions, left ventricular systolic pressure (LVSP) was 136.5 +/- 3.7 mmHg and increased to 263 +/- 5.4 mmHg when the balloon was inflated (LVMIP). LVSP was significantly lower in the presence of prazosin, metoprolol, nifedipine, and in diabetic rats. However, LVMIP was significantly reduced only in the metoprolol-treated and diabetic rats. Both LVSP and LVMIP did not change significantly in losartan-treated rats. The degree of the increase in left ventricular maximal isovolumetric pressure during balloon inflation (LVMIP-LVSP) was not significantly different in any experimental condition. These results suggest that the mechanism for evoking LVMIP is not dependent on the acute stimulation of cardiac alpha- and beta-adrenergic receptors, on calcium channels, nor on the AT1 receptors. In addition, the intrinsic mechanism for the generation of LVMIP seems not to be influenced in the diabetic state.

Adrenergic alpha-Antagonists↗
PubMed1998

Satigrel, a new antiplatelet agent, inhibits platelet accumulation in prosthetic arterial grafts.

BACKGROUND: Early and late vascular obstruction are both related to platelet adhesion and aggregation in the grafts. We assessed the effect of satigrel, a new oral antiplatelet agent, on the accumulation of indium-labeled platelets in knitted Dacron grafts inserted proximal to the femoral artery. METHODS: Nine patients with arteriosclerosis obliterans receiving grafts were treated with satigrel, and 10 others were enrolled as untreated controls. Scintigraphy was performed in postoperative weeks 2 and 4, and the ratio of the scintillation count of the graft to that of the native artery was calculated to assess platelet accumulation. RESULTS: In both weeks 2 and 4, the ratio was significantly smaller in the satigrel group than in the control group for the whole graft, the proximal anastomosis, and the distal anastomosis. CONCLUSIONS: Satigrel significantly inhibited platelet accumulation in vascular grafts and thus may be useful for preventing postoperative graft occlusion.

Aged↗
PubMed1998

Mutational analysis of the N-ras gene in acute lymphoblastic leukemia: a study of 125 Japanese pediatric cases.

A point mutation of the N-ras gene is one of the known genetic alterations identified in patients with acute lymphoblastic leukemia (ALL), but its clinical importance is still controversial. Using polymerase chain reactions, we examined codons 12, 13 and 61 of this gene in 125 Japanese childhood ALL patients (64 common-ALL, 22 pre-B-ALL, 33 T-ALL, 2 B-ALL, 3 undifferentiated ALL, and 1 unclassified ALL) including 9 relapsed patients. An N-ras point mutation was observed in 14 (11%) patients (9 common-ALL, 3 T-ALL, and 2 undifferentiated ALL; 13 patients at diagnosis and 1 at relapse). The patients with undifferentiated ALL harbored an N-ras mutation at a significantly higher rate. However, no correlation was found between the presence of an N-ras mutation and sex, age, or white blood count. There was no significant difference in the event-free survival rate between 13 fresh patients with an N-ras mutation and 103 patients with a wild-type configuration. The N-ras mutation was present in about 10% of childhood ALL cases but it did not have a prognostic impact. The sequence analyses revealed that the majority of the patients (13/14) had an N-ras mutation of a G to A transition. This finding was consistent with previous reports on N-ras mutations in acute leukemias in which the incidence of a G to A mutation was significantly higher in ALL than in myeloid malignancies.

Child↗
PubMed1998

Modified soft-balloon methods during ultrasonic probe examination for superficial esophageal cancer.

BACKGROUND AND STUDY AIMS: In ultrasonic probe studies for early-stage esophageal cancer the original soft-balloon method utilizing a condom had succeeded in obtaining a clear and reproducible picture by keeping deaerated water in a condom; however, the condom, which covered the endoscope lens, eliminated the usual endoscopic sight. Therefore, the authors endeavored to develop a modified method which enables both normal endoscopic observation and ultrasonic probe study with only a single insertion of the endoscope. PATIENTS AND METHODS: Thirty-one patients with superficial esophageal cancer were included in this pilot study. As modifications of the soft-balloon technique, two novel methods of 'wrapping' and 'invagination' were developed. RESULTS: These modifications are considered to have solved the above-mentioned problem and enable one to acquire both normal endoscopic photos and ultrasonic probe images during the same insertion of the endoscope. CONCLUSION: In a pilot study novel modifications improved the method of ultrasonic probe study for superficial esophageal cancer.

Endosonography↗
PubMed1998

Protective effect of apoptosis-inhibitory agent, N-tosyl-L-phenylalanyl chloromethyl ketone against ischemia-induced hippocampal neuronal damage.

Delayed neuronal death in the gerbil hippocampal CA1 sector occurs 48 to 72 hours after severe forebrain ischemia. DNA fragmentation is observed in the hippocampal CA1 neurons at around that time. We show here that an inhibitor of proteolytic process of apoptosis, N-tosyl-L-phenylalanyl chloromethyl ketone (TPCK), protected hippocampal neuronal damage by inhibition of the DNA fragmentation in a dose-dependent manner and that TPCK induced an apoptosis-regulating molecule, Bcl-2 protein, in the surviving neurons. These results suggest the prevention of apoptosis-related DNA fragmentation by TPCK may be an attractive therapeutic strategy for preserving hippocampal neurons from ischemic insult.

Animals↗
PubMed1998

Sulfurisphaera ohwakuensis gen. nov., sp. nov., a novel extremely thermophilic acidophile of the order Sulfolobales.

Three spherical thermoacidophilic archaea (strains TA-1T, TA-13, TA-14) were obtained from acidic hot springs located in Ohwaku Valley, Hakone, Japan. All the isolates are facultatively anaerobic, and grew optimally at around 85 degrees C, pH 2.0. Isolate TA-1T was characterized further. The G + C content of DNA from TA-1T is 33 mol%. Although these properties resemble those of the genus Acidianus, the sequence of the 16S rRNA gene from strain TA-1T was more similar to that of species of Stygiolobus than of Acidianus. DNA-DNA hybridization experiments also indicated that strain TA-1T is clearly distinguished phylogenetically from the members of Acidianus, Sulfolobus and Metallosphaera. On the basis of the distinct physiological and molecular properties, we describe the new strains as members of the new genus Sulfurisphaera. The type species of the genus is Sulfurisphaera ohwakuensis, and the type strain of the species is TA-1T (= IFO 15161T).

Base Composition↗
PubMed1998

Hypotensive mechanism of [Leu13]motilin in dogs in vivo and in vitro.

The effects of [Leu13]motilin were examined in vivo after its intravenous administration into anesthetized dogs and in vitro with isolated preparations of canine mesenteric artery. [Leu13]Motilin (0.1-10 nmol x kg(-1), i.v.) induced both strong and clustered phasic contractions in the gastric antrum and duodenum. At doses of over 1 nmol x kg(-1), [Leu13]motilin also produced transient decreases in arterial blood pressure, left ventricular pressure, maximum rate of rise of left ventricular pressure, and total peripheral resistance, and an increase in aortic blood flow and heart rate. A selective motilin antagonist, GM-109 (Phe-cyclo[Lys-Tyr(3-tBu)-betaAla] trifluoroacetate), completely abolished the gastric antrum and duodenal motor responses induced by [Leu13]motilin. In contrast, hypotension induced by [Leu13]motilin (1 nmol x kg(-1)) was unchanged in the presence of GM-109. In isolated mesenteric artery preparations precontracted with U-46619 (10(-7) M), [Leu13]motilin (10(-8)-10(-5) M) induced an endothelium-dependent relaxation, and this was inhibited by a pretreatment with N(omega)-nitro-L-arginine, a competitive inhibitor of NO synthase (10(-4) M). A high dose (10(-4) M) of GM-109 slightly decreased [Leu13]motilin-induced relaxation, and shifted the concentration-response curve of [Leu13]motilin to the right. However, the pA2 value (4.09) of GM-109 for [Leu13]motilin in the present study was conspicuously lower than that previously demonstrated in the rabbit duodenum (7.37). These results suggest that [Leu13]motilin induces hypotension via the endothelial NO-dependent relaxation mechanism and not through the receptor type that causes upper gastrointestinal contractions.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1998

Rare alteration of genomic structure or expression of the DPC4 gene in myelogenous leukemias.

We examined homozygous deletion, point mutation and expression of DPC4 gene, a recently isolated candidate pancreatic tumor suppressor gene, in 53 patients with myelogenous leukemias and 5 cell lines. The patients consisted of 34 cases of chronic myelogenous leukemia including 22 in the chronic phase, 3 in the accelerated phase, and 9 in blastic crisis, and 19 with acute myelogenous leukemia including 9 at the initial presentation and 10 at relapse. Polymerase chain reaction (PCR)-based deletion analysis for DPC4 exon 8 and PCR-single strand conformation polymorphism study for the entire coding region were carried out. Homozygous deletion or subtle mutation was not detected in any of the samples examined. However, 3 patients with various clinical phases showed a decrease of DPC4 expression. These results suggest that DPC4 alteration is not a crucial event in the development or the progression of myelogenous leukemias.

DNA-Binding Proteins↗
PubMed1998

Population pharmacokinetic analysis of mexiletine in adult arrhythmic patients in Japanese population.

We analyzed mexiletine in Japanese patients using population pharmacokinetics. 139 serum concentration data, which were collected for therapeutic drug monitoring from 121 patients, were used for this analysis. We also investigated influence of age and gender on pharmacokinetics, and age was found to be an influential factor on clearance. The final pharmacokinetic parameters are, CL/F=0.580-0.00369 x AGE (l/h/kg) and Vd/F=6.63 (l/kg). These results should be useful for adjusting the dosage to a patient's age for the prevention of an adverse reaction caused by overexposure.

Adult↗