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Biomedical subjects

Takeshi Sasaki

Publications and source records attributed to Takeshi Sasaki.

At least 19 recordsLinked to original sources

Tail-degloving and cold storage facilitate primary cell culture from wild-caught rodents.

The use of wild rodents as biological resources is hindered by the difficulties of live transport and primary culture contamination caused by skin bacteria. To address this, we developed a "tail-degloving" method to physically remove the contaminated external integument. Using the large Japanese field mouse (Apodemus speciosus), this method suppressed contamination compared to conventional biopsies, yielding cells within 5-7 days that were capable of subculturing and cryopreservation. The protocol withstood 4°C storage for up to 7 days and enabled contamination-free cell establishment from a large rodent. This tail-degloving protocol eliminates live transport risks and effectively establishes primary cells after a multi-day transport delay.

Aseptic sampling↗

Determination of gate-on and -off timing in respiration-gated radiotherapy.

The purpose of this study was to develop an efficient method of determining gate-on and -off timing in respiration-gated radiotherapy. Gate-on and -off timing in a breathing cycle were defined as the respiratory signal level for the start of irradiation (Ls) in the expiration phase and that for the end of irradiation (Le) in the inspiration phase, respectively. Thirty subjects participated in this study. The diaphragm was used as the tracking target, and time-dependent changes in the position of the target were measured together with those in the respiratory signal level. For each subject, the following maps were created by varying the combination of Ls and Le: absolute target displacement (ATD) map, relative target displacement (RTD) map, and gate-on duty cycle (GDC) map. By classifying respiratory signal waveforms, three respiratory types were derived (A: the length of end-expiration level >40% of a breathing cycle, B: the length of end-expiration level 20% of a breathing cycle, and C: the length of end-expiration level <or=40% and that of end-inspiration level <or=20% of a breathing cycle). For each respiratory type, average RTD and GDC maps were created. We presented an algorithm to obtain the optimal Ls and Le using the RTD (or ATD) and GDC maps, and this algorithm was verified by demonstrating that, in determining Ls and Le for a subject, the average RTD and GDC maps corresponding to the subject's respiratory type could be used effectively.

Adult↗

Cytoplasmic destruction of p53 by the endoplasmic reticulum-resident ubiquitin ligase 'Synoviolin'.

Synoviolin, also called HRD1, is an E3 ubiquitin ligase and is implicated in endoplasmic reticulum -associated degradation. In mammals, Synoviolin plays crucial roles in various physiological and pathological processes, including embryogenesis and the pathogenesis of arthropathy. However, little is known about the molecular mechanisms of Synoviolin in these actions. To clarify these issues, we analyzed the profile of protein expression in synoviolin-null cells. Here, we report that Synoviolin targets tumor suppressor gene p53 for ubiquitination. Synoviolin sequestrated and metabolized p53 in the cytoplasm and negatively regulated its cellular level and biological functions, including transcription, cell cycle regulation and apoptosis. Furthermore, these p53 regulatory functions of Synoviolin were irrelevant to other E3 ubiquitin ligases for p53, such as MDM2, Pirh2 and Cop1, which form autoregulatory feedback loops. Our results provide novel insights into p53 signaling mediated by Synoviolin.

Animals↗

Optical CO gas sensor using a cobalt oxide thin film prepared by pulsed laser deposition under various argon pressures.

An optical CO gas sensor was investigated using cobalt oxide thin films prepared by pulsed laser deposition. The cobalt oxide films were deposited on quartz glass and silicon wafer substrates in Ar at 0.07-133 Pa. The morphology and crystal phase of the films were changed by Ar pressure. Sensitivity was estimated as the transmittance change of the film in dry air and at 200 ppm of CO gas ambient at 350 degrees C. The morphology of the films greatly affected the sensing properties. The optimum Ar pressure for cobalt oxide film preparation for CO gas sensing was suggested to be 13.3 Pa, based on the relationship between the morphology and the optical sensor properties of the films.

Journal Article↗

Expression analyses and transcriptional regulation of mouse nucleolar spindle-associated protein gene in erythroid cells: essential role of NF-Y.

Nucleolar spindle-associated protein (NuSAP), a recently characterised microtubule-associated protein, appears to participate in cell cycle regulation. It has been demonstrated that NuSAP is expressed preferentially in the erythroid lineage in haematopoietic cells. To characterise its role in erythropoiesis, we examined the expression profile of the NuSAP gene. In fractionated murine erythroblasts, NuSAP mRNA was remarkably more abundant in the subset corresponding to immature erythroblasts (TER119(+)CD71(high)) than mature erythroblasts (TER119(+)CD71(low)), and it was significantly increased in TER119(+) cells from in vivo phlebotomised mice compared with control mice. Furthermore, during erythroid maturation of mouse erythroleukaemia (MEL) cells by dimethylsulfoxide, NuSAP mRNA was increased at 24-72 h. These results suggested that the NuSAP gene might contribute to the expansion of immature erythroblast pool. The regulatory mechanism of NuSAP gene was investigated using MEL cells. Sequence analysis revealed that NuSAP promoter has four CCAAT boxes, an Sp1 element, a GATA-like element, a CACCC element, a Myb element and lacks a TATA box. Promoter analyses demonstrated that duplicated CCAAT boxes located at -81/-85 and -30/-34 were essential for promoter activity. Furthermore, the promoter was trans-activated by NF-YA through these elements. These results suggest that NuSAP might play an important role in erythroid proliferation under the control of NF-Y.

5' Flanking Region↗

Mitogenomic analysis for coelacanths (Latimeria chalumnae) caught in Tanzania.

In recent years, a large number of individuals of the species Latimeria chalumnae, one of the living fossil coelacanths, have been landed off the coast of Tanzania. Although L. chalumnae specimens have also been landed at other localities in the western Indian Ocean, so far, viable populations of this species have been identified only at two localities, Comoros and South Africa. Therefore, the recent active catch off Tanzania suggests a new habitat for L. chalumnae. To examine the genetic background of the Tanzanian fish, we analyzed complete mtDNA sequences of two Tanzanian individuals (Kigombe-9 and Songo Mnara-1) collected from the north and south coasts of Tanzania. Using the recently reported criteria for six haplotypes established in a population genetic study for coelacanths living in the western Indian Ocean [Schartl, M., Hornung, U., Hissman, K., Schauer, J., Fricke, H., 2005. Relatedness among east African coelacanths. Nature 435, 901.], we characterized Songo Mnara-1 as haplotype 1 and Kigombe-9 as haplotype 5. We suggest that the Songo Mnara specimen is a member of the Comoran group, but was swept away by the South Equatorial current. The individual from Kigombe may be a member of an undiscovered population that exists near the boundary between Tanzania and Kenya. Further analysis using more than 19 individuals recently captured off the north coast of Tanzania will reveal whether a new population exists there. Our sequence data suggest additional variable sites in the mtDNA sequence that may define the population structure of coelacanths in the western Indian Ocean and also raise the possibility that the previously published Comoran coelacanth mtDNA sequence contains several critical errors including base changes and indels.

Animals↗

Antitumor activity of chimeric immunoreceptor gene-modified Tc1 and Th1 cells against autologous carcinoembryonic antigen-expressing colon cancer cells.

To generate tumor-specific and interferon (IFN)-gamma-producing Tc1 and Th1 cells applicable for many cancer patients, we previously developed a protocol for generating carcinoembryonic antigen (CEA)-specific Tc1 and Th1 cells from healthy human T cells by transduction with a lentivirus containing a chimeric immunoglobulin T-cell receptor (cIgTCR) gene composed of single-chain variable fragments from an anti-CEA-specific monoclonal antibody fused to an intracellular signaling domain of CD28 and CD3zeta. These cells, designated Tc1-T and Th1-T bodies, respectively, showed strong antitumor activity against CEA-expressing tumor cells in RAG2-/- mice when both of them were transferred. However, it remains unclear whether it is possible to generate Tc1-T and Th1-T bodies from cancer patients with defective T-cell function because of significant immunosuppression. Here, we prepared Tc1-T and Th1-T bodies from T cells of a colon cancer patient, and asked whether these T bodies can exert effective T-cell function against autologous tumor cells. These T bodies showed high cytotoxicity and produced IFN-gamma in response to CEA-expressing autologous tumor cells, even in the presence of soluble CEA. It was also demonstrated that Th1-T bodies supported the survival of Tc1-T bodies through cell-to-cell interactions. Furthermore, our protocol utilized retrovirus for cIgTCR transduction to achieve better induction efficiency compared to lentivirus-mediated transduction. Taken together, our findings here indicate that retrovirally transduced Tc1-T and Th1-T bodies will become a promising strategy for adoptive immunotherapy of human cancer.

Carcinoembryonic Antigen↗

Optical transmittance of indium tin oxide nanoparticles prepared by laser-induced fragmentation in water.

Laser-induced fragmentation of indium tin oxide nanoparticles was performed in water by laser irradiation with various laser energies. Fragmentation of the nanoparticles proceeded with increased laser energy. The fragmented nanoparticles showed high transmittance in the visible region and lower transmittance in the ultraviolet and infrared regions. The optical band gap of the fragmented nanoparticles increased with decreasing average particle size. The increase of the band gap was possibly caused by the Burstein-Moss effect due to the increasing concentration of carriers generated by the surface defects of the oxygen vacancies on smaller nanoparticles.

Journal Article↗

Balaenoptera omurai is a newly discovered baleen whale that represents an ancient evolutionary lineage.

Balaenoptera omurai, formerly classified as a small form of Bryde's whale, was recently reclassified as a new baleen whale species of the family Balaenopteridae. Although researchers have investigated the evolutionary history of Balaenopteridae and their relatives using molecular phylogenetic methods, the taxonomy of the ordinary Bryde's whale (Balaenoptera brydei) and small-form Bryde's whales (Balaenoptera edeni and B. omurai) remains unclear. We have used complete mtDNA sequences and short interspersed repetitive element (SINE) insertion patterns to construct the evolutionary history of both B. omurai and the taxonomically redefined species, B. edeni. The combined results demonstrate that B. omurai forms a monophyletic lineage with B. musculus, B. brydei, B. edeni and B. borealis and that B. omurai and B. musculus successively diverged from their common ancestor. In addition, we also showed that B. edeni constitutes a sister taxon to B. brydei. Our data suggest that B. omurai evolved as an ancient independent lineage that diverged much earlier than B. borealis, B. brydei and B. edeni, which were previously believed to be closely related to B. omurai.

Animals↗

Preparation of zinc oxide nanorods using pulsed laser ablation in water media at high temperature.

ZnO columnar single crystals were formed by pulsed laser ablation in deionized water and surfactant aqueous solutions of lauryl dimethylaminoacetic acid (LDA) and cetyltrimethylammonium bromide (CTAB) at 80 degrees C. ZnO particles produced by laser ablation were dissolved at a higher temperature than 60 degrees C, and then crystalline growth to columnar structure proceeded. While large ZnO columnar crystals were obtained in deionized water, the crystals prepared in surfactant solution were smaller than those in deionized water due to inhibition of crystalline growth by surfactant adsorption on ZnO surfaces. The size of ZnO nanorods depended on how surfactant molecules adsorb on ZnO surface.

Journal Article↗

Q fever with clinical features resembling systemic lupus erythematosus.

A 23-year-old woman with prolonged fever, rash, and pericarditis associated with high titers of antinuclear, anti-Sm, and anti-RNP antibodies was suspected of having systemic lupus erythematosus (SLE). However, we also considered infectious diseases, particularly Q fever, as the C-reactive protein level was elevated and the patient reported contact with zoo animals around two weeks before the onset. The condition responded rapidly to administration of minocycline; symptoms resolved without using steroids. Thereafter, no recurrence of the illness was observed. Titer of Coxiella burnetii antibody was high and the illness was accordingly diagnosed as acute Q fever rather than SLE.

Adult↗

A simple method of plaque rupture induction in apolipoprotein E-deficient mice.

OBJECTIVE: The development of a murine model of atherosclerotic plaque rupture. METHODS AND RESULTS: The left common carotid arteries of male apolipoprotein E (apoE)-deficient mice (9 weeks old) were ligated just proximal to their bifurcations. After 4 weeks on a standard diet, the mice received polyethylene cuff placement just proximal to the ligated site, and the animals were then processed for morphological studies at specific time points. Ligation of the carotid artery in apoE-deficient mice for 4 weeks induced marked intimal hyperplasia, which is a lipid- and collagen-rich lesion that contains a number of macrophages, T lymphocytes, and smooth muscle cells. Subsequently, the cuff placement evoked intraplaque hemorrhage and plaque rupture with fibrin(ogen)-positive luminal thrombus in this region accompanying a decrease in collagen content as well as an increase in apoptotic cells in the intima within a few days after cuff placement. CONCLUSIONS: We demonstrated the murine model of human plaque rupture, which is simple, fast, and highly efficient. This model would help us not only to understand the mechanism of human plaque rupture but also to assess various already-known and as-yet-unknown agents in the future.

Animals↗

Effect of MMP-2 deficiency on atherosclerotic lesion formation in apoE-deficient mice.

OBJECTIVE: Although it has been reported that matrix metalloproteinase (MMP)-2 is a major proteinase in atherosclerotic plaque lesions, there is no direct evidence of the role of MMP-2 in atherosclerotic lesion formation. In the present study we determined the role of MMP-2 in atherosclerosis plaque development using apolipoprotein E-deficient (apoE(-/-)) mice. METHODS AND RESULTS: To generate MMP-2-deficient, apoE-deficient mice (MMP-2(-/-):apoE(-/-)), MMP-2(-/-) mice were crossed with apoE(-/-) mice. After 8 weeks of feeding with a lipid-rich diet, morphological and biochemical studies of the aortic sinus and arch were conducted. A significant reduction of the atherosclerotic plaque in the aortic sinus and arch with the decrease in smooth muscle cell-positive area was observed in MMP-2(-/-):apoE(-/-) mice compared with that of MMP-2(+/+):apoE(-/-) mice. Macrophage- and collagen-positive areas were less in aortic sinus but not in aortic arch in MMP-2(-/-):apoE(-/-) mice. There was no difference of MMP-9 mRNA expression in the plaque lesion between the 2 genotypes. A much lower level of mRNA expression of TIMP-1 and TIMP-2 was detected in the atherosclerotic plaque lesions of MMP-2(-/-):apoE(-/-) mice than in those of MMP-2(+/+):apoE(-/-) mice. CONCLUSIONS: MMP-2 contributes to the development of atherosclerosis in apoE(-/-) mice.

Animals↗

An immunohistochemical scoring system of prolyl isomerase Pin1 for predicting relapse of prostate carcinoma after radical prostatectomy.

A major challenge for the management of prostate cancer (PCa) patients is to predict the clinical course of the disease after radical prostatectomy. A previous comprehensive immunohistochemical analysis using an automated image analyzer suggested that prolyl isomerase Pin1 (hence Pin1) may be a potent predictor of recurrence in PCa patients. However, a detailed pathological standard for evaluating the Pin1 immunohistochemistry in PCa has not been established yet. We here introduce a practical scoring system for Pin1 immunostaining in PCa. Using this method, the immunoreactivity of tumor cell cytoplasm and nucleus was evaluated separately and then scored for four grades (Grade=0-3). We defined the Pin1 score as the sum of both nuclear and cytoplasmic grades (Score=0-6), and the cases were then divided into either a low Pin1 score group (2) or a high Pin1 score group (3). We examined the correlation between this scoring system and postoperative PSA recurrence for 78 PCa patients. PCa patients assigned to the high Pin1 score group demonstrated PSA relapse more frequently than those assigned to the low Pin1 score group (p<0.0001). This suggests that, at the common laboratory level, our Pin1 scoring system could be a useful tool for predicting the prognosis of PCa patients after surgery.

Carcinoma↗

Two cases of Brugada syndrome associated with spontaneous clinical episodes of coronary vasospasm.

Two patients with life-threatening episodes of ventricular fibrillation (VF) showed typical ST elevation in V1-V3 leads. Both had spontaneous clinical episodes of resting angina. Intracoronary injection of acetylcholine provoked coronary vasospasm and ST elevation was the same as Brugada-type ST elevation in 1 case but not in the other. Calcium channel antagonist was prescribed to prevent coronary vasospasm but Brugada-type ST elevation and the occurrence of VF could not be prevented. The symptoms accompanied both cases. Considering these cases, the pathogenesis of Brugada syndrome should differ from that of coronary vasospasm because it could not be prevented by calcium channel antagonist.

Acetylcholine↗

Zeolite LTA Nanoparticles Prepared by Laser-Induced Fracture of Zeolite Microcrystals.

Zeolite LTA nanoparticles are prepared by laser-induced fragmentation of zeolite LTA microparticles using a pulsed laser. Zeolite nanoparticle formation is attributed to absorption of the laser at impurities or defects within the zeolite microcrystal generating thermoelastic stress that mechanically fractures the microparticle into smaller nanoparticle fragments. Experimentally, it is found that nanoparticles have a wide size and morphology distribution. Large nanoparticles (>200 nm) are typically irregularly shaped crystals of zeolite LTA, whereas small nanoparticles (<50 nm) tend to be spherical, dense, and amorphous, indicative of destruction of the original LTA crystal structure. Results of the fragmentation versus laser parameters show that shorter laser wavelengths are more efficient at producing zeolite nanoparticles, which is explained based on a larger cross section for optical absorption in the zeolite crystal. Increasing the laser energy density irradiating the sample was found to be a trade-off between increasing the amount of fragmentation and increasing the amount of structural damage to the zeolite crystal. It is suggested that in the presence of strongly absorbing defects, plasma formation is induced resulting in dramatically higher temperatures. On the basis of these results it is suggested the optimal laser processing conditions are 355 nm and 10 mJ/pulse laser energy for our LTA samples.

Journal Article↗

Resected invasive thymoma with multiple endocrine neoplasia type 1.

We report a rare case of multiple endocrine neoplasia (MEN) type 1 with thymoma. A 57-year-old woman with a chronic duodenal ulcer and hypoglycemia had been seen at a nearby clinic. Abdominal echogram revealed two nodules in the pancreas and she was referred to our hospital for evaluation. Her diagnosis was MEN type 1, gastrinoma and hyperparathyroidism with anterior mediastinal tumor. There were high calcium levels in the blood and urine. Gastrin was quite high. A chest X-ray revealed a retrosternal tumor. Computed tomography revealed an anterior mediastinal tumor without sign of invasion to the surrounding organs, and two small masses in the pancreas. Cervical echogram revealed a few masses in both sides behind the thyroid. From these findings, her preoperative diagnosis was MEN type 1 with thymic carcinoid or thymoma. We performed thymectomy and parathyroidectomy concomitantly. The mediastinal tumor was diagnosed as invasive thymoma.

Female↗

Local recurrence at hepaticojejunostomy 9 years after resection of bile duct cancer with superficial flat spread.

We report a male patient aged 45 years, who in 1993 had been diagnosed as having middle bile duct cancer and had received a pancreatoduodenectomy. Histopathology showed a nodular tumor with the main lesion in the middle bile duct and superficial spreading in both proximal and distal directions (which was not observed macroscopically), and residual tumor in the epithelium of the cut edge near the liver. The patient underwent follow-up without postoperative adjuvant therapy. In 2002, 9 years after the operation, the patient developed jaundice and was diagnosed with recurrence of bile duct cancer in the anastomotic site, based on cholangiographic results. He underwent resection of the right hepatic and caudate lobes and the anastomotic region of the bile duct and jejunum. Pathological findings showed an invasive tumor in the anastomotic region, with continuous intraepithelial spread in the direction of the bile duct, which suggested that the residual tumor in the epithelium had grown to become an invasive cancer. In this patient, the recurrence required 9 years after resection. This case provides evidence for the clinical course that might be anticipated for a patient with a residual tumor in the epithelium of the bile duct stump and subsequent superficial spreading bile duct cancer.

Adenocarcinoma↗