PubMed Health⌕ Search

Biomedical subjects

T Kawachi

Publications and source records attributed to T Kawachi.

At least 19 recordsLinked to original sources
PubMed2005

Fundamental and harmonic emission from the rear side of a thin overdense foil irradiated by an intense ultrashort laser pulse.

The emission of fundamental and harmonic radiation from the rear side of thin foils in the thickness range 50-460 nm irradiated by intense frequency doubled Ti:sapphire laser pulses of the duration of 150 fs and intensities up to a few 10(18) W/cm(2) was investigated. Following up a previous study of the rear side harmonic emission [Teubner, Phys. Rev. Lett. 92, 185001 (2004)], we measured the emission efficiencies, polarization properties, and the spectral shapes of the fundamental frequency and the second harmonic. Rear side emission is only observed when the obliquely incident laser light is p -polarized. Particle-in-cell (PIC) simulations indicate that the foils remain strongly overdense during the interaction with the laser pulse and that the rear side emission is caused by energetic electron bunches which are generated at the front side by resonance absorption. They are accelerated into the foil and drive strong plasma oscillations at the fundamental and higher harmonic frequencies.

Journal Article↗
PubMed2002

Picosecond snapshot of the speckles from ferroelectric BaTiO3 by means of x-ray lasers.

A picosecond x-ray laser speckle has been conducted to study the dynamics of a disordered surface domain structure (BaTiO3 with 90 degrees c/a domains) as a function of temperature for the first time. The transient surface structures induced by ferroelectric domains decrease as temperature increases towards the Curie temperature T(c) and completely disappear above T(c). The dramatic change of the spatial configuration of the c/a domains was observed to occur from a temperature 2 degrees C below T(c), near which the average correlated domain size at equilibrium decreases as (T(c)-T)(0.37+/-0.02).

Journal Article↗
PubMed1998

Absolute calibration of a soft X-ray spectrograph for X-ray laser research using white beam.

Absolute calibration of a soft X-ray spectrograph has been performed using a white beam of synchrotron radiation. The calibrated spectrograph was a flat-field grazing-incidence spectrograph with an X-ray CCD detector for X-ray laser research. Absolute sensitivity of the spectrograph system can be obtained from transmitted spectra using filters made of several different materials, each providing an absorption-edge wavelength standard. The absolute sensitivity determined in this work shows nearly the same behaviour with wavelength as that in another calibration experiment using a laser-produced plasma as an X-ray source.

Journal Article↗
PubMed1995

Clinical significance of tissue polypeptide antigen in serum of acute nonlymphocytic leukemia.

Tissue polypeptide antigen (TPA) in serum was measured at diagnosis in 27 patients with acute nonlymphocytic leukemia (ANLL) (1 FAB M0, 1 M1, 10 M2, 7 M3, 5 M4, 1 M5, 1 M6 and 1 MU). Statistical analysis disclosed a close correlation of TPA level with age (P < 0.01), hemoglobin level (P < 0.05), therapeutic response (P < 0.01) and the length of survival after the initial diagnosis (P < 0.02). A significant difference in TPA level was present between patients with complete remission and those with poor response. To our knowledge, this is the first report to prove a correlation of TPA level with therapeutic response and the length of survival in ANLL.

Adolescent↗
PubMed1995

Clinical significance of beta 2-microglobulin in serum of adult T cell leukemia.

To clarify the clinical and biological significance of beta 2-microglobulin (beta 2-M) in serum of adult T cell leukemia (ATL) associated with human lymphotropic virus type-I (HTLV-I), beta 2-M was measured in 52 patients with ATL (acute ATL, 35 patients; lymphoma ATL, two patients; chronic ATL, 12 patients; smoldering ATL, three patients), and it was compared with serum lactic dehydrogenase (LDH). Statistical analysis disclosed a correlation between beta 2-M level and the percentage of abnormal lymphocytes (P < 0.05) and platelet count (P < 0.01). There was a correlation between LDH and platelet count (P < 0.01), and a tendency of correlation between LDH and the percentage of abnormal lymphocytes (P < 0.15). Significant difference was present in beta 2-M as well as LDH between acute ATL and chronic ATL (P < 0.01), and between acute ATL and smoldering ATL (P < 0.01). We also investigated a significant inverse correlation between beta 2-M level as well as LDH level and the length of survival after the initial diagnosis (P < 0.01). Thus, the beta 2-M level may indicate the aggressiveness of ATL cells and predict the length of survival.

Adult↗
PubMed1992

Chromosome 11 rearrangement at band 11q21 in a patient with essential thrombocythemia.

A case of essential thrombocythemia with a partial deletion of the long arm of chromosome 11, del(11)(q21) as a sole chromosomal anomaly is reported. Rearrangement of chromosome 11 at band 11q21 has been reported in six patients with chronic myeloproliferative disorders: four with post-polycythemic myelofibrosis, one with myelofibrosis with myeloid metaplasia, and one with Ph+ chronic myeloid leukemia in blastic phase. Except for the last patient, all patients had been treated with 32P and/or an alkylating agent prior to cytogenetic examination. This is the first report of the 11q21 abnormality in essential thrombocythemia seen at diagnosis.

Adult↗
PubMed1991

[Primary bilateral adrenal lymphomas in 3 cases].

This report describes three of primary bilateral adrenal lymphoma. Case 1 was an 87-year-old female. She was admitted to our hospital because of anemia. Masses in the bilateral adrenal glands were noted on abdominal computed tomography (CT). After combination chemotherapy, bilateral adrenal masses transiently showed a remarkable reduction, but they soon enlarged and she died. The pathological diagnosis at autopsy was non-Hodgkin lymphoma (diffuse medium sized cell type). Case 2 was a 77-year-old male. He visited our hospital complaining of general malaise. Masses in the bilateral adrenal glands were noted on abdominal CT and he was admitted. The left adrenal was biopsied under echo guidance. The pathological diagnosis was non-Hodgkin lymphoma (diffuse medium sized cell type). The bilateral adrenal masses transiently responded to combination chemotherapy, but soon enlarged again and he died. Case 3 was a 75-year-old male. He visited our hospital complaining of general malaise. Masses in the bilateral adrenal glands was noted on abdominal CT and he was admitted. The left adrenal was biopsied under echo guidance. The pathological diagnosis was non-Hodgkin lymphoma (diffuse medium sized cell type). Combination chemotherapy was followed by a complete remission and discharge of the patient.

Adrenal Gland Neoplasms↗
PubMed1990

[Basic examination of deoxythymidine kinase using Prolifigen TK kit "Daiichi"].

To clarify the clinical significance of serum deoxythymidine kinase in various hematological disorders, basic examination was performed of a newly developed radioenzyme assay kit for TK (Prolifigen TK kit "Daiichi") using 125I-iodo-deoxyuridine as a substrate. The assessment of the standard curve, and the results of recovery test, dilution test, and precision and reproducibility were satisfactory. Among several anticoagulant agents tested, heparin was the best one showing no influence on the measurement of TK level. Based on these results, serum TK level was measured in 140 healthy adults as a control group. There was no difference by age and sex. The serum TK level of normal control was 3.1 +/- 1.2 U/l, with an upper limit of 5.5 U/l.

Adult↗
PubMed1984

Carcinogenicity in mice of mutagenic compounds from glutamic acid and soybean globulin pyrolysates.

2-Amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole and 2- aminodipyrido [1,2-a:3',2'-d]imidazole, potent mutagens from glutamic acid pyrolysate, were given orally to CDF1 mice of both sexes at concentrations of 0.05% in pellet diet. 2-Amino-3-methyl-9H-pyrido[2,3-b]indole and 2-amino-9H-pyrido[2,3-b]indole, potent mutagens from soybean globulin pyrolysate, were given to CDF1 mice of both sexes at concentrations of 0.08%. Hepatocellular carcinomas and hemangioendothelial sarcomas in the brown adipose tissue were induced in high incidence by all these compounds.

Animals↗
PubMed1983

Inactivation of potent pyrolysate mutagens by chlorinated tap water.

The potent mutagens 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2, 62450-07-1), 2-amino-6-methyldipyrido-[1,2-a:3', 2'-d]imidazole (Glu-P-1, 67730-11-4) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ, 76180-96-6), isolated from pyrolysates of tryptophan and glutamic acid and from broiled sardines, respectively, were effectively degraded by chlorinated tap water with a concomitant loss of mutagenicity toward Salmonella typhimurium TA98 and TA100. The half-life of 10 microM IQ in the presence of 1.5 ppm of residual chlorine was less than 10 sec; those of Glu-P-1 and Trp-P-2 were 0.5-1 and 2-3 min, respectively. This means that a glass of chlorinated tap water (150 ml) containing 1.5 ppm of residual chlorine can break down about 200 micrograms of these pyrolysate mutagens within a couple of minutes.

Carbolines↗