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Biomedical subjects

Y Togawa

Publications and source records attributed to Y Togawa.

At least 19 recordsLinked to original sources
PubMed2004

Squamous metaplasia of Paget's disease.

A patient had triple extramammary Paget's disease of both axillary and genital regions. Right inguinal lymphadenopathy was found 1 year after excision of all the skin lesions. Excisional biopsy of the lymph node demonstrated a mixture of Paget cells and atypical squamoid cells with horn pearls suggestive of keratinization. The squamoid cells were positive for cytokeratin 10, a marker of suprabasal epidermis, and also positive for laminin gamma2 which is often expressed in invasive squamous cell carcinoma. The coexistence of these different cells within the same tumour island suggested that the squamoid cells derived from metaplasia of Paget cells.

Aged↗
PubMed2000

Direct observation of the washboard noise of a driven vortex lattice in a high-temperature superconductor, Bi2Sr2CaCu2O(y)

We studied the conduction noise spectrum in the vortex state of a high-temperature superconductor, Bi(2)Sr(2)CaCu(2)O(y), subject to a uniform driving force. Two characteristic features, a broad-band noise (BBN) and a narrow-band noise (NBN), were observed in the vortex-solid phase. The origin of the large BBN was determined to be plastic motion of the vortices, whereas the NBN was found to originate from the washboard modulation of the translational velocity of the driven vortices. We believe this to be the first observation of washboard noise of dc driven vortices in any superconductor.

Journal Article↗
PubMed2000

RIKEN integrated sequence analysis (RISA) system--384-format sequencing pipeline with 384 multicapillary sequencer.

The RIKEN high-throughput 384-format sequencing pipeline (RISA system) including a 384-multicapillary sequencer (the so-called RISA sequencer) was developed for the RIKEN mouse encyclopedia project. The RISA system consists of colony picking, template preparation, sequencing reaction, and the sequencing process. A novel high-throughput 384-format capillary sequencer system (RISA sequencer system) was developed for the sequencing process. This system consists of a 384-multicapillary auto sequencer (RISA sequencer), a 384-multicapillary array assembler (CAS), and a 384-multicapillary casting device. The RISA sequencer can simultaneously analyze 384 independent sequencing products. The optical system is a scanning system chosen after careful comparison with an image detection system for the simultaneous detection of the 384-capillary array. This scanning system can be used with any fluorescent-labeled sequencing reaction (chain termination reaction), including transcriptional sequencing based on RNA polymerase, which was originally developed by us, and cycle sequencing based on thermostable DNA polymerase. For long-read sequencing, 380 out of 384 sequences (99.2%) were successfully analyzed and the average read length, with more than 99% accuracy, was 654.4 bp. A single RISA sequencer can analyze 216 kb with >99% accuracy in 2.7 h (90 kb/h). For short-read sequencing to cluster the 3' end and 5' end sequencing by reading 350 bp, 384 samples can be analyzed in 1.5 h. We have also developed a RISA inoculator, RISA filtrator and densitometer, RISA plasmid preparator which can handle throughput of 40,000 samples in 17.5 h, and a high-throughput RISA thermal cycler which has four 384-well sites. The combination of these technologies allowed us to construct the RISA system consisting of 16 RISA sequencers, which can process 50,000 DNA samples per day. One haploid genome shotgun sequence of a higher organism, such as human, mouse, rat, domestic animals, and plants, can be revealed by seven RISA systems within one month.

Animals↗
PubMed1994

Assessment of bone density in the distal radius with computer assisted X-ray densitometry (CXD).

A modified and improved radiographic absorptiometry of the distal radius which enables on-site analysis, called computer assisted X-ray densitometry (CXD), was evaluated from the viewpoint of quality assessment. Its precision and the correlation with dual energy X-ray absorptiometry (DXA) was evaluated in 12 volunteers (mean age 44.7 years). The profile of CXD-measured radial bone mineral density (RBMD) from 142 subjects (75 premenopausal and 67 postmenopausal women, mean ages 44.9 and 50.6 years, respectively) were compared with previous data by other methodologies of bone mineral analysis. The intra-assay coefficient of variation (CV) was 0.617%, the inter-assay CV was 2.064%, and the inter-observer CV was 0.673%. The correlation between CXD-measured RBMD and DXA-measured RBMD was of statistical significance (r2 = 0.733, P < 0.01). The correlation of CXD-measured RBMD with age, height or weight corresponded well with previous reports. CXD-measured RBMD and DXA-measured vertebral bone mineral density (VBMD) also had a significant positive correlation, but their correlation was not so close (r2 = 0.149, P < 0.01). The discriminative ability of osteoporosis by CXD was of acceptable level (odd's ratio = 5.72, P < 0.05), when assessed by comparison with bone dystrophy score (BDS) on the plain vertebral radiogram. Although some problems remain in technical standardization, CXD could be an easy, inexpensive, and widely applicable alternative of non-weight bearing cancellous bone densitometry.

Absorptiometry, Photon↗
PubMed1993

Doppler color flow imaging in the detection and quantitative measurement of the gastroduodenal artery blood flow.

The purpose of this article was to investigate the detection rate of gastroduodenal artery blood flow (GDABF), and to measure its velocity and volume flow rate using Doppler color imaging. The GDABF was detected in 40 of 41 (98%) normal subjects with longitudinal scanning and in 36 (88%) with transverse scanning. The velocity of the GDABF was 21 +/- 8 cm/sec (m +/- SD) and the volume flow rate was 67 +/- 20 mL/min. Without color Doppler, the vascular lumina of the GDA was demonstrated in 27 (66%) subjects by longitudinal scanning and in 26 (63%) by transverse scanning. The hemodynamics of the GDA were revealed noninvasively using Doppler ultrasonography in a patient with a malignant islet cell tumor of the pancreas and one with a ductal cell carcinoma of the pancreas.

Adenocarcinoma↗
PubMed1990

Quantification of physical and cyto-physiological conditions for the electrofusion of Saccharomyces cerevisiae.

Various conditions for obtaining hybrids of the auxotrophic mutants SH1509 and SH1512 of Saccharomyces cerevisiae by electrofusion were investigated. An AC field of 400 Vp/cm and a DC field of 2 square pulses (7 kV/cm; 60 microsec each) at an interval of 0.5 sec were effective. Treatment with 0.2 (SH1509) or 1.0 mg/ml (SH1512) Zymolyase for 1 or 1.5 hr was essential. As to the molarity of the osmotic stabilizer (sorbitol), the hybrid yield peaked at 0.6 M. The presence of CaCl2 (up to 0.4 mM) or 0.1 mM CaCl2 with 0.1 mM MgCl2 enhanced the yield. The temperature of the spheroplast suspension during pulsations also affected the yield, the most suitable temperature being 28 degrees C.

Buffers↗
PubMed1989

The diagnostic accuracy of magnetic resonance imaging in pancreatic carcinoma based on a retrospective analysis of vascular involvement.

A retrospective analysis was made to evaluate the diagnostic accuracy of magnetic resonance (MR) imaging for pancreatic cancer. Twenty-one lesions from 21 patients with pancreatic cancer were examined and all except one, were identified on MR images by a disparity in contrast and/or morphological enlargement. The patients were divided into 3-groups, based on the relationship between the tumor and the portal vein, seen on the MR images. These groups were defined as the separate, touching, and surrounding groups. The MR findings correlated with the findings at laparotomy in 16 patients, 10 of whom underwent tumor excision. In the remaining 4, the MR findings correlated with the angiographic findings. The presence or absence of vascular involvement was correctly diagnosed in 18 of the 21 patients. MR imaging proved useful for detecting pancreatic cancer and cancerous infiltration into the portal vein. MR imaging should therefore aid the surgeon in determining the operability and/or curability of patients with pancreatic cancer.

Adult↗
PubMed1987

Enhanced antitumor efficacy with a combination of hyperthermochemotherapy and thermosensitization with polyamine antimetabolites in nude mice.

In an attempt to enhance the antitumor effects of hyperthermochemotherapy, methylglyoxal-bis-guanylhydrazone (MGBG) and alpha-difluoromethylornithine (DFMO) were used in combination with hyperthermochemotherapy of 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosoure a (ACNU) against human gastric cancer (ST-2) xenotransplanted into nude mice. After priming with DFMO and MGBG, ACNU was given ip and subsequently, a 23 minute-hyperthermia was carried out by placing the leg with the tumor into a water bath of a temperature of 43.5 +/- 0.1 degrees C. The second hyperthermic treatment was given in the same manner after 48 hours. MGBG and DFMO were administered for 4 successive days from the previous day of the first hyperthermia. In mice treated with DFMO plus MGBG, either tumor growth or tumor tripling time was much the same as in the control, while in mice given MGBG, DFMO plus heat, there was a diminution in tumor growth. Hyperthermia together with MGBG, DFMO plus ACNU brought about remarkable antiproliferative effects on ST-2 tumor growth, compared to three regimens with MGBG, DFMO plus heat, MGBG, DFMO plus ACNU, as well as ACNU plus heat. These data suggest that a combination of MGBG with DFMO leads to a favorable thermosensitization to the antitumor efficacy of ACNU.

Animals↗
PubMed1986

Combined therapy of polyamine antimetabolites and antitumor drugs for human gastric cancer xenotransplanted into nude mice.

Antitumor therapies using polyamine antimetabolites combined with 1-(4-amino-2-methyl-5-pyrimidyl)methyl-3(2-chloroethyl)-3-nitrosourea (ACNU) or fluorinated pyrimidines for human gastric cancer xenotransplanted into nude mice were studied to determine inhibiting post-therapeutic regrowth of the tumor after cessation of antitumor treatments with polyamine antimetabolites alone. ACNU 20 mg/kg, fluorinated pyrimidine, 5-FU 52.8 mg/kg and 5'-deoxy-5-fluorouridine (5'-DFUR) 100 mg/kg as well as polyamine antimetabolites, alpha-difluoromethylornithine (DFMO) 1000 mg/kg and methylglyoxal-bis-guanylhydrazone (MGBG) 50 mg/kg were given intraperitoneally for 5 successive days. When DFMO and MGBG were combined with ACNU, the post-therapeutic regrowth was definitely inhibited, while combined treatments with 5-FU or 5'-DFUR did not inhibit the regrowth. Post-therapeutic DNA biosynthesis was suppressed in mice given DFMO, MGBG plus ACNU. On the contrary, in mice treated with DFMO, MGBG plus 5-FU or 5'-DFUR, suppression of DNA biosynthesis was not observed. Tumor tissue spermine levels in the DFMO, MGBG plus 5-FU or 5'-DFUR group remained unchanged, compared to those in the DFMO + MGBG group. In mice given DFMO, MGBG plus ACNU, however, spermine levels were markedly depressed; and the ACNU alone depressed also the tissue spermine levels. These different results between nitrosourea and fluorinated pyrimidines may relate to mechanisms of action of these antitumor drugs.

Animals↗
PubMed1983

[Experimental study on the effect of direct currents on the internal remodeling of a long bone cortex].

The effects of direct currents on internal remodeling were examined using femurs of 21 adult mongrel dogs. The left femurs of all dogs, used as a control, were inserted electrodes only, which were not electrically stimulated. In Group 1, no surgery was done on the right femur. In Group 2, 1 microA continuous direct current (D. C.) was applied for 6 weeks; in Group 3, 10 microA for 2 weeks; in Group 4, 10 microA for 4 weeks; in Group 5, 10 microA for 6 weeks; in Group 6, 10 microA for 16 weeks; and in Group 7 100 microA for 6 weeks. Each group was composed of three dogs. The following histomorphometric parameters were measured to evaluate the effects of electrical stimulation: number of resorption cavities (Ar), number of secondary osteons with osteoid seam (osAf), linear rate of mineralization of osteoid seam (Mo), perimeter of osteoid seam (Sf), cross-sectional area of secondary osteon (Ah) and bone formation rate (Vf). The following results were obtained: In Group 1, resorption cavities and secondary osteon with osteoid seam were observed more in the left femur than in the right. Then, mechanical stimulation of periosteal stripping or cortical drilling enhanced internal remodeling of cortical bone. In other groups (electrical stimulation was applied on the right femur), it seems that internal remodeling, especially activation frequency, was enhanced by D. C. No significant change was noted in the linear rate of mineralization of osteoid seam and cross-sectional area of the secondary osteons. Bone formation rate in the right femur showed increment when length of stimulating period had increased from 2 to 6 weeks. In Group 6 and 7, the enhanced area of bone formation has increased in cross-section, although in Group 7, bone necrosis was observed around the electrode in the right femur. Therefore, the optimum current of electrical stimulation may be just or slightly more than 10 microA. Bone formation rate was correlated with volume of callus in the marrow cavity within the period of six weeks.

Animals↗
PubMed1982

[Effect of tiemonium iodide on colonic motility in dogs].

Effects of tiemonium iodide (tiemonium, 20 micrograms/kg), mepenzolate bromide (mepenzolate, 20 micrograms/kg), butylscopolamine bromide (butylscopolamine, 50 micrograms/kg) and atropine sulfate (atropine, 10 micrograms/kg) on the colonic motility in dogs were evaluated using a balloon method. The frequency of the wave motion was analyzed by fast Fourier transform, and the power spectra were obtained. The value of the first term of the power spectrum is regarded as an indication of the colonic tonus. Inhibitory effects of tiemonium on both the normal proximal colonic motility and the accelerating motility induced by neostigmine metylsulfate (neostigmine, 50 micrograms/kg) were equal to those of butylscopolamine. In the case of distal colonic motility, tiemonium showed potent mepenzolate-like inhibition. When the drugs were injected into the veins after administration of PGF2 alpha (10 micrograms/kg), all of the drugs depressed the colonic constriction induced by PGF2 alpha. The colonic motility was not restored by the administration of tiemonium or mepenzolate before the injection of PGF2 alpha, but such an effect was not observed in the case of butylscopolamine and atropine. It is suggested that tiemonium shows an extensive inhibition on the colonic motility in the mode of mepenzolate-like action and by some additional mechanism.

Animals↗