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Biomedical subjects

T Kadono

Publications and source records attributed to T Kadono.

At least 19 recordsLinked to original sources
PubMed2006

Theory and characteristics of transition radiation emitted by low-energy storage-ring synchrotrons for use in X-ray lithography.

Existing theory is developed further for description of transition radiation (TR) emitted by low-energy storage-ring synchrotrons. It takes into account the fact that the dielectric constant of the TR target material is a complex function, introduces an expression for the number of passes of an injected electron through the target, and accounts more precisely for the absorption of TR. It is shown that the consideration of the complexity of the dielectric constant results in notable changes of the TR spectrum for emitted photons with energies close to the ionization energies of the target material. Since such TR is used mostly for performing X-ray lithography (XRL), the sensitivity of the photoresist used in XRL is formulated. Maximization of this resist sensitivity can be used for designing optimum targets for XRL. Study of the transmission of TR through a commonly used XRL mask, and its partial absorption in a common photoresist, illustrates that TR emission with E = [490, 1860] eV is most useful for performing such XRL, while E approximately equal to 1 keV is best. It is shown that, for a particular target material, a target consisting of only one foil emits the most TR energy. Optimization of an Al target, based on maximization of the resist sensitivity, indicates that a target containing one Al foil with a thickness of about 200 nm would be best for performing XRL by our low-energy storage-ring synchrotron MIRRORCLE-20SX.

Computer Simulation↗
PubMed2006

Analysis of gene mutations in four cases of dermatofibrosarcoma protuberans.

Fusion of the collagen type I alpha 1 (COL1A1) gene with the platelet-derived growth factor B-chain (PDGFB) gene has been described in dermatofibrosarcoma protuberans (DFSP). Various exons of the COL1A1 gene have been shown to be involved in the fusion with exon 2 of the PDGFB gene. We examined the breakpoints of the COL1A1 gene using the tumour specimens from four patients with DFSP. The COL1A1-PDGFB fusion transcripts were detected from the cultured tumour cells by reverse transcriptase polymerase chain reaction. Sequence analysis revealed that the ends of exons 23, 25, 26 and 36 in the COL1A1 gene were fused with the start of exon 2 in the PDGFB. This study identified three novel COL1A1 breakpoints: exons 23, 26 and 36 of the COL1A1 gene. In one case, the tumour was composed of two areas that differed in cytological atypia, cellularity and mitotic activity, indicating the dedifferentiation of the tumour. In tumour cells from two different areas the same aberrant fusion transcripts were identified. These results suggest that the dedifferentiation of tumour cells has nothing to do with the specific breakpoints of the COL1A1 gene, but depends on other unknown factors.

Adult↗
PubMed2005

Subaru telescope observations of Deep Impact.

The impact cratering process on a comet is controversial but holds the key for interpreting observations of the Deep Impact collision with comet 9P/Tempel 1. Mid-infrared data from the Cooled Mid-Infrared Camera and Spectrometer (COMICS) of the Subaru Telescope indicate that the large-scale dust plume ejected by the impact contained a large mass (approximately 10(6) kilograms) of dust and formed two wings approximately +/-45 degrees from the symmetric center, both consistent with gravity as the primary control on the impact and its immediate aftermath. The dust distribution in the inner part of the plume, however, is inconsistent with a pure gravity control and implies that evaporation and expansion of volatiles accelerated dust.

Cosmic Dust↗
PubMed2005

Deep Impact: observations from a worldwide Earth-based campaign.

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

Cosmic Dust↗
PubMed2004

Flow cytometric studies of the host-regulated cell cycle in algae symbiotic with green paramecium.

Paramecium bursaria (green paramecium) possesses endosymbiotically growing chlorella-like green algae. An aposymbiotic cell line of P. bursaria (MBw-1) was prepared from the green MB-1 strain with the herbicide paraquat. The SA-2 clone of symbiotic algae was employed to reinfect MBw-1 cells and thus a regreened cell line (MBr-1) was obtained. The regreened paramecia were used to study the impact of the host's growth status on the life cycle of the symbiotic algae. Firstly, the relationship between the timing of algal propagation and the host cell division was investigated by counting the algal cells in single host cells during and after the host cell division and also in the stationary phase. Secondly, the changes in the endogenous chlorophyll level, DNA content, and cell size in the symbiotic algae were monitored by flow cytometry and fluorescence microscopy. The number of algae was shown to be doubled prior to or during the host cell division and the algal population in the two daughter cells is maintained at constant level until the host cell cycle reenters the cytokinesis, suggesting that algal propagation and cell cycle are dependent on the host's cell cycle. During the host's stationary growth, unicellular algal vegetatives with low chlorophyll content were dominant. In contrast, complexes of algal cells called sporangia (containing 1-4 autospores) were present in the logarithmically growing hosts, indicating that algal cell division leading to the formation of sporangia with multiple autospores is active in the dividing paramecia.

Animals↗
PubMed2002

Mid-term outcome after partial left ventriculectomy in pediatric patients.

From May 1998 to April 2000, we performed partial left ventriculectomy (PLV) in 3 pediatric patients with dilated cardiomyopathy (DCM). At the time of the surgery, their age ranged from eight months to three years. The first patient eventually had to receive a heart transplant, but all patients treated with PLV are alive to this day. Patient #1 was diagnosed with DCM at the age of five months, PLV was done on a semi-urgent basis at the age of eight months, when medium dose IV catecholamine therapy and mechanical ventilation were required. Fraction shortening (FS) as shown by echocardiography increased postoperatively from 8% to 15% along with marked clinical improvement. Her heart failure deteriorated three months after the surgery, and received a heart transplant in the United States when she was one year and two months old. Patient #2 developed severe heart failure two months after correction of a ventricular septal defect. Aggressive medical therapy failed to improve his condition, therefore PLV was done on an elective basis at the age of three years and five months. [The patient was initially hospitalized and underwent low dose catecholamine.] Postoperative course was well. The ventriculography one year after surgery showed an improvement of the left ventricular FS from 12% to 27% after PLV. He was still doing well at his most recent check up. Patient #3 was diagnosed with DCM as a neonate. PLV was done on an elective basis at the age of two years and five months. Her postoperative course was generally well. FS on echocardiography increased postoperatively from 10% to 25% along with marked clinical improvement. The timing of performing PLV is the most essential factor for postoperative course in our experiences. We consider that the best timing is when aggressive catecholamine infusion or mechanical ventilation is required. The mid-term outcome of PLV of pediatric patients is considered to be acceptable. We believe that PLV should be considered as a viable option for severe DCM patients.

Cardiac Surgical Procedures↗
PubMed2001

Differential growth regulation in human melanoma cell lines by TIMP-1 and TIMP-2.

We investigated the role of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in the growth regulation. Primary (PM-WK and KHm-4), recurrent primary (RPM-EP and RPM-MC), lymph node metastatic (MM-AN, MM-BP and MM-RU), and a visceral metastatic (MM-LH) melanoma cell lines were used. Reverse transcriptase-coupled polymerase chain reaction and Western blotting revealed that all expressed and produced TIMP-1 and TIMP-2 except for PM-WK, which neither expressed nor produced TIMP-1. TIMP-1 and TIMP-2 secretion levels were measured by enzyme-linked immunosorbent assay in supernatants of cells. We found that the TIMP-1 production level was correlated with the cell migration rate. Moreover, TIMP-1 enhanced the cell migration of PM-WK. The growth of the primary melanoma cell lines was stimulated by TIMP-1 and inhibited by TIMP-2. In contrast, the growth of the visceral metastatic melanoma cell line was stimulated by TIMP-2.

Cell Division↗
PubMed2001

Males in rural Bangladeshi communities are more susceptible to chronic arsenic poisoning than females: analyses based on urinary arsenic.

Spot urine samples were collected from the inhabitants of two rural communities in northwestern Bangladesh. We compared arsenic levels in the urine samples ([As](u); n = 346) with those in water from tube wells ([As](tw); range < 1-535 microg/L; n = 86) on an individual basis. The small variation of [As](u) within subjects and highly positive correlation with [As](tw) indicate that [As](u) is a useful indicator of exposure. Analyses of [As](u) showed that creatinine correction was necessary, that [As](u) only reflected recent exposure, and that there were substantial interindividual differences for a given [As](tw) level. To evaluate the toxic effects of arsenic exposure, we constructed a system for rating skin manifestations, which revealed distinct sex-related differences. Comparison of males and females in the same households confirmed that skin manifestations were more severe in the males, and in the males of one community a dose-response relationship between [As](u) and the degree of skin manifestation was evident. The results of this study indicate that [As](u) in spot urine samples can be used as an exposure indicator for As. They suggest that there might be sex-related, and perhaps community-related, differences in the relationship between [As](u) and skin manifestations, although several confounding factors, including sunlight exposure and smoking habits, might contribute to the observed sex difference. The existence of such differences should be further confirmed and examined in other populations to identify the subpopulations sensitive to chronic arsenic toxicity.

Adult↗
PubMed2001

CHST1 and CHST2 sulfotransferase expression by vascular endothelial cells regulates shear-resistant leukocyte rolling via L-selectin.

Sulfation is an essential component of the selectin ligands, potentially mediated by members of a new family of carbohydrate sulfotransferases. In this study, we assessed the contributions of CHST1, CHST2, CHST3, and CHST4 in producing functional L-selectin ligands. Human umbilical vein endothelial cells predominantly expressed CHST1 and CHST2 transcripts with low levels of CHST3 mRNA, while cytokine activation up-regulated CHST2 expression and induced low-level CHST4 expression. A human umbilical vein endothelial cell line, EA.hy926, displayed functional L-selectin ligands that correlated with CHST1 and CHST2 expression in the absence of CHST4 expression. Increased CHST1 or CHST2 expression by a cell line expressing low-level L-selectin ligand activity during in vitro flow chamber assays increased rolling leukocyte numbers, reduced rolling velocities, and enhanced leukocyte rolling under higher shear stresses. These results suggest that CHST1 and CHST2 contribute to the generation of optimal L-selectin ligands in vascular endothelial cells at sites of inflammation.

Animals↗
PubMed2000

Acquired digital arteriovenous malformation: a report of six cases.

Arteriovenous malformation (AVM) is usually congenital, but an acquired type is also known, of which most are due to a previous injury. We report six patients with acquired digital AVM, all having a small patch of AVM localized to the tip of one finger, and therefore quite different from ordinary AVM which consists of a large pulsatile mass. Histologically, dilated venous and arterial vessels were present in the dermis. Tumour-like growth was absent; thus, these six cases could be differentiated from arteriovenous haemangioma. Because of the characteristic anatomical site, unique clinical manifestations and histology, this appears to be a new and distinctive entity.

Adolescent↗
PubMed2000

Expressions of various growth factors and their receptors in tissues from neurofibroma.

BACKGROUND: Platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta are known to enhance the growth of neurofibroma-derived cells from neurofibromatosis type 1 (NF-1) patients. OBJECTIVE: This study aims to elucidate whether these growth factors and their receptors are up-regulated in NF-1 patients. METHODS: Tissues and culture cells from neurofibroma in NF-1 patients, nontumor lesions in NF-1 patients, and the skin of normal controls were collected. To evaluate the expressions of growth factors and their receptors, reverse-transcriptase polymerase chain reaction and immunohistochemistry were performed. RESULTS: PDGF-beta receptor subunit was expressed in the neurofibroma tissues from NF-1 patients, but not in the nontumorous tissues from NF-1 patients or skin from normal controls. As for the other factors, there were no significant differences among these tissues. Neurofibroma sections also stained positive for the PDGF-beta receptor subunit. CONCLUSIONS: The interaction of PDGF and PDGF-beta receptor subunit may be important in the tumorigenesis of NF-1.

Becaplermin↗
PubMed1998

Basal cell carcinoma with neuroid type nuclear palisading: a report of three cases.

Nuclear palisading is a characteristic feature which is typically seen in neural tumours such as neurilemmoma, and also in some other tumours. We report here three patients with basal cell carcinoma who showed histological patterns similar to nuclear palisading. To our knowledge, this is the first such case report in the medical literature; we apply the term 'neuroid-type nuclear palisading' to these cases. In our patients, the spindle-shaped tumour cells were tightly packed and the nuclei were arranged uniformly to form this rare feature.

Aged↗
PubMed1998

Serum concentrations of vascular endothelial growth factor in collagen diseases.

Vascular endothelial growth factor (VEGF) is an angiogenic cytokine which has been reported to be important in the pathogenesis of rheumatoid arthritis (RA). In this study, the serum level of VEGF was measured using enzyme-linked immunosorbent assay in 17 patients with systemic lupus erythematosus, 49 patients with polymyositis/dermatomyositis (PM/DM), 40 patients with systemic lupus erythematosus, 49 patients with polymyositis/dermatomyositis (PM/DM), 40 patients with systemic sclerosis (SSc), 11 patients with RA and 20 control subjects. The VEGF level was 184 +/- 62 pg/mL (mean +/- SD) in the serum of normal individuals. The mean VEGF levels in the patients with PM/DM or RA were significantly higher than in the normal controls. In 21 of the 49 patients with PM/DM and nine of the 11 patients with RA, the serum VEGF level was considered to be elevated. In patients with SSc, those with diffuse cutaneous SSc showed elevated VEGF levels in comparison with normal controls. An elevated serum VEGF level was correlated with the frequency of lung fibrosis and reduced vital capacity in the patients with SSc.

Adolescent↗
PubMed1998

Increased production of interleukin 6 and interleukin 8 in scleroderma fibroblasts.

OBJECTIVE: To determine additional abnormal characteristics related to cytokines in fibroblasts derived from systemic sclerosis (SSc), we examined the production of interleukin 6 (IL-6) and IL-8 and their mRNA levels both in scleroderma fibroblasts and in those from normal skin. METHODS: Cultured fibroblasts from patients with SSc and healthy controls were examined. Production of IL-6 and IL-8 was assessed by specific ELISA, and the levels of IL-6 and IL-8 mRNA were determined by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Basal production of both IL-6 and IL-8 was significantly increased in scleroderma fibroblasts compared with controls. When cells were stimulated with either IL-1beta (50 pg/ml) or tumor necrosis factor-alpha (TNF-alpha: 10 ng/ml), the production of IL-6 and IL-8 was predominantly increased in both cell strains and there was no significant difference in the production of IL-6 and IL-8 between them. When normal fibroblasts were stimulated with IL-1beta for 48 h and subcultured, both IL-6 and IL-8 production were significantly increased, and production remained elevated even after 3 passages. RT-PCR revealed that IL-6 and IL-8 mRNA were detected in scleroderma fibroblasts but not in normal skin fibroblasts without cytokine stimulation. When stimulated with IL-1beta, both cell strains expressed IL-6 and IL-8 mRNA to almost the same extent. CONCLUSION: Increased production of IL-6 and IL-8 by scleroderma fibroblasts suggests that these cells may have been stimulated by certain cytokines in vivo.

Cells, Cultured↗