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Biomedical subjects

K Imai

Publications and source records attributed to K Imai.

At least 181 records · Page 10Linked to original sources
PubMed2001

Meta-analysis of multiple myeloma and benzene exposure.

Epidemiologic studies have suggested that benzene exposure may be a risk factor of multiple myeloma (MM). We performed meta-analyses of case-control studies to assess the association between occupational exposure to benzene and the risk of MM. We divided the occupational sources of benzene exposure into 4 categories, benzene and/or organic solvents, petroleum, petroleum products, and engine exhaust, for conducting the meta-analysis. As a result, a significant positive association was indicated between exposure to engine exhaust and MM (summary odds ratio or summary OR=1.34, 95% confidence interval or 95%CI=1.14-1.57). However, no significant associations were obtained for benzene and/or organic solvents (summary OR=0.74, 95%CI=0.60-0.90), petroleum (summary OR=1.11, 95%CI=0.96-1.28) and petroleum products (summary OR=1.08, 95%CI=0.89-1.33) with risk of MM. These results suggested that benzene exposure itself was not likely to be a risk factor of MM. It is thought that several harmful chemical agents in engine exhaust, other than benzene, could be etiologically related to the risk of MM. Further case-control studies on MM are needed to obtain more information about detailed occupational exposure to toxic substances.

Air Pollutants, Occupational↗
PubMed2001

Sodium 1-monolinolenin isolated from Italian ryegrass (Lolium multiflorum Lam) induces apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sodium 1-monolinolenin (SML) which was isolated from the leaves of Italian ryegrass (Lolium multiflorum Lam) and identified by Mass, and (1)H- and (13)C-NMR, led to both growth inhibition and induction of programmed cell death (apoptosis). Morphological change showing apoptotic bodies was observed in the Molt 4B cells treated with SML. The fragmentation by SML of DNA to oligonucleosomal-sized fragments, that is a characteristic of apoptosis, was observed to be both concentration- and time-dependent. These findings suggest that growth inhibition by SML of Molt 4B cells results from the induction of apoptosis in the cells.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Sesamolin from sesame seed inhibits proliferation by inducing apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sesamolin, a component of sesame seed led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with sesamolin. The fragmentation of DNA by sesamolin to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These findings suggest that growth inhibition of Molt 4B cells by sesamolin results from the induction of apoptosis in the cells.

Antineoplastic Agents↗
PubMed2001

[Magnetoencephalography analysis of epileptic foci].

Magnetoencephalography (MEG) is very useful for presurgical evaluation for epilepsy surgery because of its high spatio-temporal resolution. Interictal spikes are usually analysed by MEG, whereas ictal studies are performed using EEG or SPECT. We investigated cases in which MEG and other physiological or radiological examinations revealed discordant results. The most important is precise clinical symptomatology. When combined with clinical informations, MEG can be a powerful tool for analyzing epileptic foci. Now pediatric epileptologists should discuss and treat intractable cases with epilepsy surgeons. In Japan, there are only few integrated, epilepsy diagnosis and treatment teams (comprehensive epilepsy programs). They should be widely established in university hospitals and reference centers.

Child↗
PubMed2001

Expression of heparanase mRNA in bovine placenta during gestation.

This study reports the identification and sequence of a partial cDNA for bovine heparanase and the expression of its mRNA in the placenta during gestation. The 364 amino acid residues deduced from the 1092 bp cDNA fragment share 81.9% and 80.5% identity with amino acid sequences of human and rat heparanase, respectively. Northern blot hybridization showed that two mRNAs (2.0 and 3.5 kb) are strongly expressed in placenta, and weakly expressed in the kidney, lung, spleen and non-pregnant uterus. In the placenta, these transcripts were detected in the cotyledon at all stages of gestation examined, and in the intercotyledonary fetal membrane and caruncle on day 60, day 120 and day 260. Quantitative real-time RT-PCR analysis showed very low expression of heparanase mRNA in the conceptus before implantation (day 17), but high expression in the cotyledon-containing fetal membrane (days 27-34) after implantation. Furthermore, heparanase mRNA was detected in the cotyledon, intercotyledonary fetal membrane and caruncle after days 60-64 of gestation. However, no significant expression of heparanase mRNA was observed in intercaruncular endometrium at all stages of gestation examined. These results demonstrate that heparanase mRNA is expressed in the placentome, indicating that heparanase may play a role in implantation, and in placental development and function.

Amino Acid Sequence↗
PubMed2001

Sesaminol from sesame seed induces apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sesaminol, a component of sesame oil led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with sesaminol. The fragmentation of DNA by sesaminol to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These findings suggest that growth inhibition of Molt 4B cells by sesaminol results from the induction of apoptosis in the cells.

Apoptosis↗
PubMed2001

Expression of the gamma(2) chain of laminin-5 at the invasive front is associated with recurrence and poor prognosis in human esophageal squamous cell carcinoma.

PURPOSE: Preferential expression of the gamma(2) chain of laminin-5 in invading carcinoma cells has been implicated in tumor invasion. The aim of this study was to clarify the clinicopathological and prognostic significance of laminin gamma(2) chain expression in esophageal squamous cell carcinoma (SCC). EXPERIMENTAL DESIGN: We analyzed the association between immunohistochemically detected laminin gamma(2) chain expression in esophageal SCC and clinicopathological characteristics, and we investigated whether laminin gamma(2) chain is a predictor of recurrence and/or survival. RESULTS: The cytoplasm of carcinoma cells was stained for laminin gamma(2) at levels much stronger than those in normal esophageal basement membrane. The immunoreactivities at the invasive front were often more intense than those at the superficial layer. Sections with immunostaining signals in >30% of carcinoma cells at the invasive front, which were observed in 44 of 100 cases, were judged to be positive for laminin gamma(2) chain. Laminin gamma(2) chain positivity was significantly correlated with depth of invasion, lymph node metastasis, distant metastasis, advanced pTNM stage, recurrence, and recurrence within the first postoperative year. Patients with laminin gamma(2) chain-positive carcinoma had a significantly shorter disease-free and overall survival time than did those with laminin gamma(2) chain-negative carcinoma. Laminin gamma(2) chain retained its significant predictive value for disease-free and overall survival in multivariate analysis that included conventional clinicopathological factors. CONCLUSIONS: Our results suggest that the laminin gamma(2) chain plays a key role in the progression of esophageal carcinoma and that its detection is useful for the prediction of recurrence and poor prognosis.

Biomarkers, Tumor↗
PubMed2001

Electrophysiological analysis of chronic atrial fibrillation associated with mitral valve disease by using spectral analysis.

Several authors have suggested that periodic activation is related to maintenance of atrial fibrillation (AF). The aim of this study was to examine periodic electrical activations in both atria that may lead to the generation and maintenance of AF associated with valvular diseases by means of fast Fourier transform (FFT) analysis. Atrial electrograms (AEGs) were analyzed in 15 persistent AF patients, who underwent pulmonary vein orifice (PVO) isolation with mitral valve surgery. Intraoperatively, AEGs of 4 seconds duration were acquired at 48 epicardial sites, 24 each from the right and left atrium (RA, LA). Dominant peaks (DPs) examined using FFT were present in 26% of all sampling points (380/1440). Prominent clustering of DPs was mostly observed on the LA. The mean AF cycle length (mAFCL) estimated from DP frequency was significantly shorter in LA than that in RA (178 +/- 32 msec vs 247 +/- 58, p = 0.0003). The shortest AF cycle length in each patient was mainly found in the LA. The PVO isolation procedures successfully eliminated AF in 87% of patients (13/15). In cases of recurred AF (2/15), the difference in mAFCL between bilateral atria was significantly smaller than in the case of successful AF elimination (17 +/- 7 msec vs 76 +/- 56, p = 0.042). FFT analysis of intraoperative mapping data clarified that periodic activity was present predominantly in LA. It may be possible to predict the efficacy of surgical procedures for eliminating AF using this technique.

Adult↗
PubMed2001

[Usefulness of combination post-stress dysfunction and perfusion imaging in technetium-99m-tetrofosmin myocardial scintigraphy].

OBJECTIVES: Myocardial perfusion imaging has lower sensitivity for the diagnosis of coronary artery disease in patients with three-vessel disease. The presence of post-stress dysfunction of the left ventricle, evaluated by electrocardiography(ECG) gated single photon emission computed tomography(SPECT) with a quantitative gated SPECT program, was investigated in patients with coronary artery disease, and also whether combining post-stress dysfunction and myocardial perfusion imaging improved the diagnosis of coronary artery disease. METHODS: ECG gated technetium-99m-tetrofosmin SPECT was performed using a one day, stress and rest, protocol in 139 patients. SPECT and coronary angiography were performed within 1 month. The coronary artery disease group consisted of 89 patients: 43 with one-vessel disease(1VD), 28 with two-vessel disease(2VD), and 18 with three-vessel disease(3VD). The group with zero-vessel disease(0VD) consisted of 50 patients. According to post-stress and rest ejection fraction(EF) and end-systolic volume (ESV), post-stress dysfunction is defined as follows: rest EF--post-stress EF > or = 5% and post-stress ESV--rest ESV > or = 5 ml. RESULTS: In the coronary artery disease group, post-stress ESV was larger than rest ESV(37.8 +/- 26.4, 34.0 +/- 24.2 ml, p < 0.001), and post-stress EF was lower than rest EF (61.5 +/- 11.1%, 64.2 +/- 10.8%, p < 0.001). In the 0VD group, ESV and EF were the same for post-stress and rest (25.7 +/- 20.8, 26.2 +/- 21.6 ml, NS; 70.4 +/- 9.5%, 70.0 +/- 9.6%, NS). Post-stress dysfunction was 6.0% in the 0VD group and 30.3% in the coronary artery disease group(p < 0.001). Furthermore, post-stress dysfunction in the 2VD (35.7%) and 3VD(38.9%) groups was higher than that in the 0VD group(p < 0.01, p < 0.01). Sensitivity of coronary artery disease diagnosis by myocardial perfusion imaging was 75%. The combination of post-stress dysfunction and myocardial perfusion imaging improved sensitivity from 75% to 82%(p < 0.05), but reduced the specificity from 92% to 86%(p = 0.08). CONCLUSIONS: Post-stress dysfunction is a useful parameter for clinical diagnosis of coronary artery disease.

Aged↗
PubMed2001

[Three-dimensional computed tomography angiography of coronary artery bypass graft with electron beam tomography].

OBJECTIVES: Assessment of coronary artery bypass graft patency by three-dimensional reconstructed computed tomography angiography (3D-CTA) derived from electrocardiography-gated contrast-enhanced electron beam tomography (EBT) was evaluated. METHODS: Thirty-nine patients with 99 grafts (45 arterial grafts and 54 venous grafts) underwent 3D-CTA and selective coronary angiography within a 3-week interval. 3D-CTA images of the coronary bypass grafts were compared with the coronary angiography images used as the control. RESULTS: 3D-CTA defined 42 of 44 arterial grafts as patent (sensitivity: 95%), all 47 venous grafts as patent (sensitivity: 100%) and all 7 venous grafts as occlusive (specificity: 100%). The overall sensitivity and specificity were 98% and 88%, respectively. CONCLUSIONS: 3D-CTA is an useful noninvasive technique with adequate sensitivity and specificity to assess coronary artery bypass graft patency.

Aged↗
PubMed2001

[Usefulness of CT-guided RFA for hepatocellular carcinoma].

US-guided puncture is the simplest and most popular method in the RFA treatment for HCC. However, depending on the location of tumors, it is often difficult to detect them by US. We report here the utility of CT-guided RFA for the treatment of HCC. We performed CT-guided RFA for 27 nodules in 21 patients with HCC from July 1999 to June, 2001. We used the LeVeen Needle Electrode made by Boston Company and the Cool-tip type electrode made by Radionics Company. We judged the effects of the treatment by dynamic CT within 7 days after RFA. We were able to accomplish the treatment for all patients with the exception of one case who developed severe pain during RFA. We experienced transient increases of AST/ALT in a few cases, subcutaneous emphysema in one case, pleural effusion and ascites in two cases, but conservative treatments were effective for all cases. US-guided puncture was especially useful for the treatment of the tumors localized below the diaphragm that were hardly detectable by US.

Aged↗