Biomedical subjects

T Ikeda

Publications and source records attributed to T Ikeda.

At least 91 records · Page 5Linked to original sources

PubMed2001

The role of video-assisted thoracoscopic surgery in the diagnosis of the small peripheral pulmonary nodule.

BACKGROUND: The use of imaging techniques to detect small peripheral pulmonary nodules often results in a missed diagnosis. Thoracoscopy had limited application until recently, when advances in technology allowed thoracic surgeons greater visualization and mobility within the chest. METHODS: Between September 1992 and June 1997, 81 patients were treated for small peripheral pulmonary nodules by pulmonary wedge excision using video-assisted thoracoscopic techniques. The patients were 39 men and 42 women with an average age of 59.5 years. RESULTS: A definitive diagnosis was obtained in all cases. Malignancies were found in 44 patients (55%), which involved primary lung cancer in 28 patients and metastatic lesions in 16 patients. The rate of malignancy in nodules measuring 1 cm or less was 18%. There was no operative mortality or morbidity. CONCLUSIONS: We conclude that video-assisted thoracoscopic lung biopsy is a more effective and less invasive diagnostic tool for small peripheral pulmonary nodules.

Female↗

PubMed2001

t(11;14)(q23;q24) generates an MLL-human gephyrin fusion gene along with a de facto truncated MLL in acute monoblastic leukemia.

More than 20 different partner genes with MLL have been cloned from leukemia cells with translocations involving chromosome 11 band q23 (11q23). All reported partner genes fused in-frame to MLL and the fusion cDNA encode chimeric MLL proteins with a significant portion derived from the partner genes. We analyzed one patient with de novo acute monoblastic leukemia with t(11;14)(q23;q24) and identified that a human homologue of gephyrin (human gephyrin) fused with MLL. Gephyrin is a rat glycine receptor-associated protein, which forms submembranous complexes and anchor glycine or gamma-aminobutyric acidA receptors to microtubules. Alternative splicing of human gephyrin gene created two different forms of fusion cDNA. In one form, human gephyrin gene fused in-frame to MLL exon 9, and the chimeric product had COOH terminus of human gephyrin protein, including the tubulin binding site. In the other, the reading frame terminated shortly after the fusion point. As a result, only seven amino acids with no known function were attached to the NH2 terminus of MLL protein. The functional significance of this de facto truncated MLL gene product is not clear.

Aged↗

PubMed2001

Synthesis and photochromism of spirobenzopyran derivatives bearing an oxymethylcrown ether moiety: metal ion-induced switching between positive and negative photochromisms.

Spirobenzopyran derivatives carrying an oxymethylcrown ether moiety were synthesized, and their photochromism was studied in the presence of various metal ions in acetonitrile. The metal ion complexing ability of the crown ether moiety in crowned spirobenzopyrans affects both thermal isomerization and photoisomerization of their spirobenzopyran moiety to a great extent. When the interaction of the crown ether moiety with a metal ion was strong enough to cause thermal isomerization of the spirobenzopyran moiety to its corresponding merocyanine form and to suppress UV-induced isomerization to the merocyanine form, a negative photochromism appears. On the other hand, a relatively weak interaction of the crown ether moiety with a metal ion affords a positive photochromism. This phenomenon enables us to switch the photochromic behavior between positive and negative photochromisms.

Journal Article↗

PubMed2001

Supramolecular polar thin films built by surfactant liquid crystals: polarization-tunable multilayer self-assemblies with in-plane ferroelectric ordering of ion-based dipoles.

Polar order in the phosphonium liquid crystal thin films, which are composed of two-dimensional ion-pair-based domains separated by the insulating hydrocarbon layers, was probed by second harmonic generation (SHG) analysis. Despite the ordinary amphiphilic self-assemblies containing no pi-electron moieties, the solid-state thin films retaining a smectic layer structure showed clearly an SHG activity, while the disordered films without the layer structure were not active at all for the SHG. It was found that the multilayer structure plays a crucial role for the SHG from the phosphonium thin films and the ionic layers act as an SHG-active site. The most significant characteristic of this system is to possess an ability to control SHG intensity electrically. The efficiency of the SHG process in the thin-film assemblies was enhanced by applying an external electric field parallel to the layer plane. Furthermore, through evaluation of thermal stability of the sample films, it was revealed that the SHG signals were detected only in the solid-state temperature range and the disappearance of the SHG occurs earlier than the solid-to-liquid crystalline phase transition. These results demonstrated that the origin of polar order in the phosphonium thin films is due to in-plane noncentrosymmetric arrangement (ferroelectric ordering) of ion pairs as an electric dipole, that is, dipole symmetry in an ionic layer.

Journal Article↗

PubMed2001

Chrysotile asbestos fibers mediate transformation of Escherichia coli by exogenous plasmid DNA.

The ability of chrysotile asbestos fibers to introduce the exogenous plasmid pUC18 into Escherichia coli JM109 cells was tested. Cells were transformed with pUC18 DNA although the frequency of transformation was quite low: 759+/-301 transformants were obtained per microgram of pUC18. Plasmids were purified from E. coli which had been transformed by mediation with chrysotile asbestos. Following this, the plasmids were confirmed to be pUC18 by Southern hybridization. This asbestos-mediated transformation was optimal within 5 min when 10 mg ml(-1) of asbestos was used. Plasmids up to 7.69 kb were introduced by this method.

Asbestos, Serpentine↗

PubMed2001

Nerve growth factor down-regulates the expression of norepinephrine transporter in rat pheochromocytoma (PC12) cells.

Functional expression of norepinephrine transporter (NET) and its regulation were examined in rat pheochromocytoma cell line, PC12. Nerve growth factor (NGF) decreased [3H]-norepinephrine (NE) uptake in association with a decrease in NET mRNA levels. On the other hand, levels of tyrosine hydroxylase mRNA increased in PC12 cells treated with NGF for 4-24 h, while Oct-2 mRNA levels decreased at 4 h with NGF then recovered for 8-24 h in the presence of NGF. Both bFGF and EGF reduced [3H]NE uptake, although they failed to affect NET mRNA levels. To examine the NET transcriptional regulation, we identified the 5'-noncoding region of rat NET mRNA by the rapid amplification of cDNA end (RACE) method and cloned the 5'-flanking region of NET gene. The newly identified exon encodes the untranslated region of rat NET mRNA upstream of the known 5'-region including ATG start codon. Constructs having green fluorescent protein (GFP) as reporter were made with the cloned NET gene, and promoter activity was examined in CHO and SK-N-SH cells transiently transfected and in PC12 cells stably transfected with NET-GFP constructs. The results indicate that the 2.1 kb NET flanking region displays promoter activity and is responsible for the NGF-induced down-regulation of NET expression.

5' Untranslated Regions↗

PubMed2001

Ionic Strength Effects of Electrolytes on Solubilized States of Water in AOT Reversed Micelles.

The limiting amounts of solubilized aqueous NaCl, NaNO(3), MgCl(2), and AlCl(3) in sodium 1,2-bis-(2-ethylhexyloxycarbonyl)-1-ethanesulfonate (aerosol OT)/isooctane solutions have been measured as a function of the ionic strength of the electrolytes. In any system, the limiting amounts increased up to the optimal ionic strength (Io(opt)), and afterward, as ionic strength increased, they decreased and were followed by a constant. These increased and decreased curves of water solubilization below and above Io(opt), called, respectively, salting-in and salting-out curves, could be interpreted, respectively, from the counteracting effects of attractive intermicellar interaction and interfacial bending stress. The effects of electrolytes on the solubilized states of water by micelles were examined using NMR and near-infrared spectroscopic techniques. Consequently, two types of waters, i.e., water bound directly to the ionic head groups of the surfactant in reversed micelles and water interacting with the hydrated head groups in swollen micelles through hydrogen bonds, were almost unaffected by any electrolytes, whereas much greater effects were observed for bulklike water in W/O microemulsions. The order of the degree of lowering of salting-out curves in W/O microemulsion regions in each system was found to agree with the Hofmeister series. Copyright 2001 Academic Press.

Journal Article↗

PubMed2001

Selective and long-term learning impairment following neonatal hypoxic-ischemic brain insult in rats.

We examined four different learning and memory tasks in rats which had been subjected to left carotid artery ligation followed by 2 h hypoxia (8% oxygen) when they were 7 days old. The examination began on the 4th week after insult and continued to 18 weeks post-insult. Compared with the control group, the hypoxic-ischemic group showed significant learning impairments in choice reaction time tasks relating to the attention process, and in plus-maze tasks and water maze tasks which examine long-term reference memory. In eight-arm radial maze tasks representing both short-term working memory and long-term reference memory, inferiority of the hypoxic-ischemic group was transient. Results of the sensorimotor test were normal in the hypoxic-ischemic group although slight flexion and twisting in the right forelimb was observed in 30% of the hypoxic-ischemic group when suspended by the tail. These abnormalities did not affect the results of learning tests. Findings of the study indicate that left-side brain damage produced by hypoxia-ischemia at 7 days of age resulted in selective and long-lasting learning and memory impairment.

Animals↗

PubMed2001

Activation of Reg gene, a gene for insulin-producing beta -cell regeneration: poly(ADP-ribose) polymerase binds Reg promoter and regulates the transcription by autopoly(ADP-ribosyl)ation.

The regeneration of pancreatic islet beta cells is important for the prevention and cure of diabetes mellitus. We have demonstrated that the administration of poly(ADP-ribose) synthetase/polymerase (PARP) inhibitors such as nicotinamide to 90% depancreatized rats induces islet regeneration. From the regenerating islet-derived cDNA library, we have isolated Reg (regenerating gene) and demonstrated that Reg protein induces beta-cell replication via the Reg receptor and ameliorates experimental diabetes. However, the mechanism by which Reg gene is activated in beta cells has been elusive. In this study, we found that the combined addition of IL-6 and dexamethasone induced the expression of Reg gene in beta cells and that PARP inhibitors enhanced the expression. Reporter gene assays revealed that the -81 approximately -70 region (TGCCCCTCCCAT) of the Reg gene promoter is a cis-element for the expression of Reg gene. Gel mobility shift assays showed that the active transcriptional DNA/protein complex was formed by the stimulation with IL-6 and dexamethasone. Surprisingly, PARP bound to the cis-element and was involved in the active transcriptional DNA/protein complex. The DNA/protein complex formation was inhibited depending on the autopoly(ADP-ribosyl)ation of PARP in the complex. Thus, PARP inhibitors enhance the DNA/protein complex formation for Reg gene transcription and stabilize the complex by inhibiting the autopoly(ADP-ribosyl)ation of PARP.

Animals↗

PubMed2001

Application of capillary electrophoresis to monitor populations of Cellulomonas cartae KYM-7 and Agrobacterium tumefaciens KYM-8 in mixed culture.

A bacterial cell mixture ot Cellulomonas cartae KYM-7 and Agrobacterium tumefaciens KYM-8 was analyzed by capillary zone electrophoresis (CZE) and capillary gel electrophoresis (CGE). Both pherograms showed two discrete peaks. The cells in the peaks were collected, Gram stained, and examined with a microscope. The cells of the two strains were well separated by OGE, and each OGE peak consisted almost entirely of cells of one strain (greater than 98% purity), whereas each CZE peak contained cells of both strains (about 90% purity). In the concentration range of 1.0 x 10(10) to 1.0 x 10(12) cells/mL, the area of CGE peaks was proportional to the amount of cells. The growth of the two strains in mixed culture was measured by OGE. The OGE quantification data were in good agreement with those obtained using fluorescence in situ hybridization. The CGE analyses were accomplished in 1 h, using a relatively uncomplicated procedure. Thus, OGE exhibited great advantages in accuracy, rapidity, and simplicity.

Actinomycetales↗

PubMed2001

Effects of prenatal styrene exposure on postnatal development and brain serotonin and catecholamine levels in rats.

Maternal reproductive effects in Wistar rats exposed to 0, 50, or 300 ppm styrene for 6 h/day during gestational days 6 to 20 were evaluated. Their offspring were observed postnatally for neurochemical changes, growth, and physical landmarks of development. Mothers exposed to styrene were compared with pair-fed and ad-lib-fed controls in order to adjust nutrient conditions. Prolongation of the gestational period, food intake, and the number of neonatal deaths or stillbirths in 300-ppm-exposed dams showed evidence of styrene-related effects. Other reproductive parameters, such as litter size, birth weight, and sex ratio, were found to exhibit no effects within the variation range studied. A neurochemical effect was observed in that the 5-HT and HVA concentrations in cerebrum were significantly decreased. Incisor eruption (mandible), eye opening, and the air-righting reflex were delayed in rat pups born to dams receiving 300 ppm styrene exposure compared with the pair-fed and ad lib control groups. Pups born to dams exposed to 50 ppm styrene also had a significantly delayed air-righting reflex compared with ad lib controls. These results suggest that the offspring were susceptible to the effects of styrene on a few developmental landmarks even when nutritional effects were controlled.

Animals↗

PubMed2001

The chicken RelB transcription factor has transactivation sequences and a tissue-specific expression pattern that are distinct from mammalian RelB.

Rel/NF-kappaB proteins are eukaryotic transcription factors that control the expression of genes involved in a large variety of cellular processes. Rel proteins share a highly conserved DNA-binding/dimerization domain called the Rel Homology (RH) domain. We have constructed and characterized a composite cDNA encoding most of the chicken RelB transcription factor. The predicted chicken RelB protein has a high degree of sequence similarity to other vertebrate RelB proteins within the RH domain, but is much less conserved outside this domain. Chicken RelB does not bind DNA as a homodimer, but forms DNA-binding heterodimers with NF-kappaB p50 or p52. Overexpressed chicken RelB localizes to the nucleus in chicken embryo fibroblasts, and the nonconserved C-terminal sequences of chicken RelB contain a transactivation domain that functions in chicken and mouse fibroblasts. Thus, chicken RelB has functional properties similar to other vertebrate RelB proteins. However, Western blotting of diverse chicken tissues indicates that chicken RelB is more widely expressed than mammalian RelB.

Active Transport, Cell Nucleus↗

PubMed2001

Compact, reliable ventricular assist device as a bridge to recovery or for semipermanent use.

OBJECTIVES: The magnetically suspended centrifugal pump has gained attention as an implantable ventricular assist device for long-term use. We report recovery-oriented pump operation and results of a chronic animal experiment. METHODS: In an acute experiment in 8 sheep having microspheres injected to induce heart failure, left ventricular assist was implemented by 2 inflow cannulas, 1 each in the left atrium and left ventricle. The pressure-volume loop of the left ventricle and myocardial oxygen consumption were measured varying the assist rate. The chronic animal experiment used 10 sheep whose native heart was kept intact. Continuous hemodynamic monitoring and periodic blood sampling were conducted. RESULTS: In the acute study, myocardial oxygen consumption decreased proportionally with increasing assist rate in left atrial drainage, but was significantly less at a 100% assist rate in left ventricular drainage. External work in left ventricular drainage did not decrease until a 75% assist rate, suggesting that the left ventricle shape and size were maintained despite decreased myocardial oxygen consumption. In the chronic experiment, the pumping duration was 14 to 248 days. No thrombi or emboli in the pump or any major organ were found in sacrificed sheep after living more than 100 days. Hepatic and renal function were within an almost normal range throughout the experiment. CONCLUSION: Left ventricular blood drainage effectively reduced oxygen consumption, maintaining the shape of the left ventricle. The magnetically suspended centrifugal pump is suitable for recovery of a failing heart or semipermanent use.

Animals↗

PubMed2001

Bullectomy is beneficial in the pulmonary blood flow/driving pressure relationship in bullous emphysema patients.

OBJECTIVES: Few physiological studies have been on pulmonary circulation, including the relationship between pulmonary blood flow and driving pressure, and viscosity changes arising from hematocrit changes before versus after lung volume reduction Surgery or bullectomy in emphysematous patients. METHODS: We studied the relationship between pulmonary blood flow and driving pressure before and after bullectomy using a unilateral pulmonary artery occlusion test based on pulmonary blood flow fractions obtained by pulmonary blood flow scintigraphy in 7 patients with pulmonary emphysema associated with bullae. RESULTS: Among the 7 undergoing bullectomy, the pulmonary blood flow/driving pressure relationship decreased in 5 and was unchanged in 2. Of the 11 lungs treated by bullectomy, this relationship decreased in 8 lungs, but not 3 (p < 0.01). No significant difference was seen in oxygen partial pressure in arterial and mixed venous blood or hematocrit. CONCLUSION: We concluded that bullectomy shifted the pulmonary blood flow/driving pressure relationship downword in some cases with significant bullae.

Aged↗

PubMed2001

Nitinol stent for the treatment of tracheobronchial stenosis.

OBJECTIVE: The purpose of this study was to evaluate the potential utility of implantation of a nickel-titanium alloy (nitinol) stent for the treatment of malignant or benign tracheobronchial stenosis. METHODS: We evaluated 18 patients (14 men and 4 women) who received 24 nitinol stents, between November 1997 and May 2000. All 18 patients had severe dyspnea caused by tracheobronchial stenosis. The underlying condition was malignant disease in 15 patients, and benign tracheal collapse in the other 3 patients. RESULTS: Implantation of the stent was successfully performed in all patients. Seventeen patients experienced immediate clinical improvement in respiratory symptoms. The remaining 1 patient with a bronchial fistule after lobectomy did not benefit, and died of pneumonia at 16 days after the implantation. In 15 patients, the procedure was performed using a flexible bronchoscope under local anesthesia alone, while the remaining 3 patients needed intravenous sedation. There was no complication resulting from the stent implantation. Among the 3 patients with benign tracheal collapse, 2 patients were alive at 746 and at 401 days after the stent implantation, at the time of this report. One patient with cicatricial stenosis after intubation died of heart failure due to previous myocardial infarction. Among the 15 patients with malignant disease, 4 patients have survived for 177 to 305 days to date, while the other 11 patients have died of primary malignancy with a mean survival duration of 60.2 days. CONCLUSION: The nitinol stent was effective in treating malignant or benign tracheobronchial stenosis, and had some remarkable advantages compared with other tracheobronchial stents. In stenting, most procedures can be performed using flexible bronchoscope under local anesthesia.

Adult↗

PubMed2001

Immediate surgical rescue for mediastinal compression by giant metastatic lung tumor.

Mediastinal compression by a large metastatic lung tumor is a life-threatening condition and needs immediate decompression. We performed palliative surgical rescue for 2 patients aged 42 and 30 years with these conditions, and were able to control their symptoms. Patients were free of symptoms soon after the operation. Palliative surgical rescue can relieve the symptoms immediately and improve the general condition dramatically. We think that surgical rescue is worthwhile, especially for younger patients.

Adult↗

PubMed2001

Evaluation of bone metabolic markers in breast cancer with bone metastasis.

PURPOSE: In the present study, four bone metabolic markers were examined to clarify them meaning and clinical value in the detection of bone metastasis (BM) from breast cancer. METHODS: we examined serum carboxyterminal telopeptide of type I collagen (ICTP), tartrate resistant acid phosphatase (TRACP), total alkaline phosphatase (ALP) and urinary type I collagen cross-linked N-telopeptides (NTx) as potential markers. These bone markers were evaluated simultaneously in 156 breast cancer patients; 114 patients without metastasis (group A), 23 patients with BM (group B) and 19 patients with metastasis at sites other than bone (group C). RESULTS: The mean values of ICTP and TRACP in group B were significantly greater than those in group A. Group B consisted of the patients with varying degrees of BM and variation in their treatments. The patients in group B were divided into BM (+) and BM (++) according to hot spots in bone scan. ICTP and TRACP were elevated in BM (++) patients compared to BM (+) patients (p<0.05). The values of ICTP and TRACP of the twelve patients without treatment in group B were significantly higher than those in group A. In the treated patients of group B, the mean values of ICTP and TRACP were lower in responders and cases of stable disease than those with progression. NTx and ALP were inferior to ICTP and TRACP for clinical evaluation of BM. CONCLUSIONS: We confirmed that ICTP and TRACP might be useful markers for screening and monitoring BM in breast cancer.

Acid Phosphatase↗

PubMed2001

Resistant mechanisms of anthracyclines--pirarubicin might partly break through the P-glycoprotein-mediated drug-resistance of human breast cancer tissues.

Juliano and Ling initially reported the expression of a 170 kDa glycoprotein in the membrane of Chinese hamster ovarian cells in 1976, and named this glycoprotein P-glycoprotein (P-gp) based on its predicted role of causing "permeability" of the cell membrane. After much research on anthracycline-resistance, this P-gp was finally characterized as a multidrug-resistant protein coded by the mdr1 gene. Multidrug resistance associated protein (MRP) was initially cloned from H69AR, a human small cell-lung carcinoma cell line which is resistant to doxorubicin (DXR) but does not express P-gp. MRP also excretes substrates through the cell membrane using energy from ATP catabolism. The substrate of MRP is conjugated with glutathione before active efflux from cell membrane. Recently, membrane transporter proteins were re-categorized as members of "ATP-Binding Cassette transporter"(ABC-transporter) superfamily, as shown at http://www.med.rug.nl/mdl/humanabc.htm and http://www.gene.ucl.ac.uk/nomenclature/genefamily/abc.html. A total of ABC transporters have been defined, and MDR1 and multidrug resistance associated protein 1 (MRP1) were reclassified as ABCB1 and ABCC1, respectively. Their associated superfamilies include 11 and 13 other protein, in addition to ABCB and ABCC, respectively. Lung resistance-related protein (LRP) is not a member of the superfamily of ABC transporter proteins, because it shows nuclear membrane expression and transports substrate between nucleus and cytoplasm. LRP was initially cloned from a non-small cell lung carcinoma cell line, SW1573/2R120 which is resistant to DXR, vincristine, etoposide and gramicidin D and does not express P-gp. The mechanisms of resistance remains unclear, and why some resistant cell lines express P-gp and others express MRP and/or LRP is likewise unclear.

ATP-Binding Cassette Transporters↗