Search PubMed⌕ Search

Biomedical subjects

T Masuda

Publications and source records attributed to T Masuda.

At least 901 records · Page 50Linked to original sources

Luciferase cDNA from Japanese firefly, Luciola cruciata: cloning, structure and expression in Escherichia coli.

We have cloned the cDNA for luciferase from lantern poly(A)+ RNA of a Japanese firefly, Luciola cruciata (Genji botaru in Japanese). This cDNA directed the synthesis of enzymatically active luciferase under the control of the lac promoter in Escherichia coli. The amino acid sequence predicted from the cDNA sequence shows that Genji firefly luciferase consists of 548 amino acids and has a molecular weight of 60,024. Considerable sequence homology was found upon the comparison of the Genji and North American firefly luciferases.

Amino Acid Sequence↗

Mutagenicity and DNA-damaging activity of decomposed products of food colours under UV irradiation.

Five synthetic food colours Food Red Nos 3, 40 and 102 and Food Blue Nos 1 and 2, and their UV irradiated products were tested for mutagenic activity by means of the Ames test using Salmonella typhimurium strains TA98 and TA100. Food colours were irradiated with UV light for 14 days. Food Red Nos 3, 40 and 102 and Food Blue No. 1 were non-mutagenic before and after irradiation. UV irradiated products of Food Blue No. 2 were mutagenic in TA98 with or without S-9 mix. The mutagenic activity increased with increasing irradiation period, reached maximum potency on day 6, and then decreased. Moreover, Food Blue No. 2 showed DNA-damaging activity after 14 days of irradiation in rec-assay using Bacillus subtilis strains H17 and M45. The capillary electrophoresis was applied for the analysis of UV irradiated products of Food Blue No. 2. The original peak of Food Blue No. 2 was decomposed into seven peaks after UV irradiation.

Bacillus subtilis↗

Detection of apoptosis in keloids and a comparative study on apoptosis between keloids, hypertrophic scars, normal healed flat scars, and dermatofibroma.

Recent studies have suggested that the regulation of apoptosis during wound healing is important in scar establishment and the development of pathological scarring. In this study, we demonstrate that keloid fibroblasts can be identified as apoptotic cells because of their highly condensed chromatin and discrete nuclear fragments. To further reveal the phenomenon of apoptosis, we quantified the number of terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells in surgically resected tissues of keloids (N = 10), hypertrophic scars (N = 10), normal healed flat scars (N = 10), and dermatofibroma (N = 10). The number of TUNEL-positive cells was relatively low, but was significantly higher for the keloid group compared with the normally healed flat scar group (p = 0.004), suggesting reduced cell survival and increased apoptotic cell death in a subpopulation of keloid fibroblasts. Furthermore, the number of TUNEL-positive cells was significantly higher for the keloid group compared with the dermatofibroma group (p = 0.044), suggesting that a subpopulation of keloid fibroblasts may suppress tumorgenicity at a greater rate than dermatofibroma by undergoing cell death. Hypertrophic scars had significantly higher levels of apoptosis than normally healed flat scars (p = 0.033). Therefore, these results suggest that selected fibroblasts in keloids and hypertrophic scars undergo apoptosis, which may play a role in the process of pathological scarring.

Adolescent↗

Follicular bronchiolitis (FBB) associated with Legionella pneumophilia infection.

An 8-month-old girl with respiratory distress and stridor was admitted to the authors' hospital. Two days later, she died of respiratory insufficiency due to pneumonia. Autopsy confirmed the presence of follicular bronchiolitis (FBB) in both lungs. After considering her clinical course, the authors focused on three pathogens: Legionella pneumophilia, Pneumocystis carinii, and Mycobacterium tuberculosis. Only Legionella pneumophilia was detected by both immunohistochemistry and PCR.

Bronchiolitis↗

Follicular bronchiolitis associated with Legionella pneumophilia infection.

An 8-month-old girl with respiratory distress and stridor was admitted to our hospital. Two days later, she died of respiratory insufficiency due to pneumonia. Autopsy confirmed the presence of follicular bronchiolitis (FBB) in both lungs. After consideration of her clinical course, we focused on three pathogens: Legionella pneumophilia, Pneumocystis carinii, and Mycobacterium tuberculosis. Only Legionella pneumophilia was detected by both immunohistochemistry and polymerase chain reaction.

Bronchiolitis↗

Effects of internal filtration on the solute removal efficiency of a dialyzer.

To improve solute removal efficiency, several types of dialyzers with enhanced internal filtration were introduced for clinical application. In these dialyzers, enhanced internal filtration increased convective transport of the solute, in addition to diffusive transport. In this study, the effects of internal filtration on solute removal efficiency were examined by both analytic and experimental studies. Internal filtration is affected by blood (Q(B)) and dialysate (Q(D)) flow rates; the patient's hematocrit and plasma level of total protein; and the effective length (L(eff)), inner diameter (D), and density ratio (DR) of the hollow fibers. An analytic model was introduced for the estimation of the changes in mass and momentum along the dialyzer. It clarified the effects of these parameters on maximum internal filtration flow rate (Q(IF)) and clearance (K) of urea (60 daltons), vitamin B(12) (1,355), and myoglobin (17,000). As a result of the analytic study, Q(IF) was increased, resulting in a smaller D, a longer L(eff), and a larger DR value. Several types of dialyzers with the same cellulose triacetate membrane, produced by Toyobo Co, Ltd., Ohtsu, Japan, and Nissho Corporation, Kusatsu, Japan, were used for the experimental study. An in vitro evaluation using myoglobin solution showed the same trends as found in the analytic study. For example, a dialyzer with 150 microm of D has a 72.0 ml/min myoglobin K value, much higher than that of 53.7 ml/min for a dialyzer with 200 microm of D under constant Q(B) (300 ml/min) and DR (50%) values. Development of a dialyzer with enhanced internal filtration, however, should take the patient's safety into account, and hemolysis and endotoxin invasion from the dialysate to the patient should be avoided.

Filtration↗

Magnetization transfer contrast imaging of the cervical spine at 0.3 T.

OBJECTIVE: We assessed the efficacy of magnetization transfer contrast (MTC) imaging of the cervical spine in conjunction with a gradient recalled echo (GRE) technique using a 0.3 T permanent magnet imager. MATERIALS AND METHODS: Seventy patients were prospectively investigated. Multislice sagittal and axial images of the cervical spine with and without MTC were obtained using a GRE sequence (TR/TE/flip angle = 750 ms/23 ms/25 degrees). The contrast-to-noise ratios (C/Ns) for CSF versus cord or disk were calculated for quantitative analysis. Qualitative image analysis was also performed. RESULTS: Both sagittal and axial MTC images had significantly higher C/N values than conventional GRE images. The MTC images showed better differentiation between the CSF and the cord or thecal sac as well as better delineation of the nerve roots. Furthermore, MTC images demonstrated syringomyelia more clearly than conventional images. CONCLUSION: Magnetization transfer contrast images at 0.3 T are effective for diagnosing diseases of the cervical spine.

Adolescent↗

Transtrochanteric anterior rotational osteotomy for slipped capital femoral epiphysis: a report of five cases.

We have performed a transtrochanteric anterior rotational osteotomy on five patients with severe chronic slipped capital femoral epiphysis. Four patients were free from clinical symptoms, whereas one patient continued to feel a dull pain in the hip. Radiographic evaluation indicated that the osteotomy was able to correct even a severe slip without any deformity around the trochanteric region. There were complications in two cases: a posteromedial tilt at the osteotomy site and a focal avascular necrosis in the anterolateral epiphysis.

Adolescent↗

Congenital melanoma: a case suggesting rhabdomyogenic differentiation.

A newborn girl had some subcutaneous masses within a giant congenital melanocytic nevus in the left parietal area. Microscopic examination revealed melanoma. The tumor consisted of two different patterns, being composed partly of epithelioid cells and partly of spindle-shaped cells. Immunohistochemically the epithelioid cells showed a positive reaction for HMB-45 and NKI/C3, and a negative reaction for desmin and alpha-sarcomeric actin. The spindle-shaped cells showed a negative reaction for HMB-45 and NKI/C3, and a positive reaction for desmin and alpha-sarcomeric actin. Ultrastructurally the spindle-shaped cells had some schwannian features, namely, a basal lamina, interdigitating cell processes, and junctional complexes. The pathologic findings of our case suggest possible direct rhabdomyogenic differentiation of melanoma cells.

Antigens, Neoplasm↗

A case of thyrotropin (TSH)-secreting tumor complicated by periodic paralysis.

A 27-year-old man had symptoms of hyperthyroidism and periodic paralysis. While hyperthyroid, his serum thyrotropin (TSH) level was inappropriately elevated at 6.4 microU/ml. The serum alpha subunit level was also elevated. MR imaging revealed a pituitary tumor and transsphenoidal adenomectomy was performed. Immunocytochemistry with an antibody directed against the beta-subunit of TSH revealed a TSH-secreting tumor. This is the first case of hyperthyroidism due to a TSH-secreting pituitary tumor complicated by periodic paralysis. This association indicates that thyrotoxicosis may induce paralysis in susceptible persons by a mechanism which is not autoimmune.

Adenoma↗

influence of concentration and mannuronate/guluronate [correction of gluronate] ratio on steady flow properties of alginate aqueous systems.

Steady flow properties were measured at various concentrations for aqueous systems of alignates with different mannuronate/gluronate (M/G) ratios using a cone-plate type rheometer. The flow curve (a plot of shear stress vs. shear rate) shows a plateau region, which is ascribed to a heterogeneous structure, at low shear rate. This plateau region is more noticeable in the G-rich systems than in the M-rich systems. On the other hand, the flow curves for the systems with the same molecular weight but different M/G ratios are congruent in the high shear rate region. The zero shear viscosity can be reduced by the segment contact parameter, cMw, for the alginates with the same M/G ratio but different molecular weights. The zero shear viscosity is proportional to cMw in a low concentration region and is proportional to (cMw)3.4 at relatively high concentrations. The critical value of cMw for which the zero shear viscosity changes from proportionality with cMw to proportionality with (cMw)3.4 is ca. 900.

Alginates↗

Rheological properties and fractal structure of concentrated polyion complexes of chitosan and alginate.

Rheological properties and fractal structure of the polyion complex between chitosan and alginate have been studied using IR spectra, dynamic viscoelasticity and SAXS measurements. The complexation seems to occur between a carboxyl anion of the alginate and an amino group of the chitosan. The complex develops most markedly at a mixing ratio in weight of the chitosan/alginate from ca. 1/1 to 1/2 (in molar ratio), at which the dynamic viscoelastic functions of the systems manifest a plateau region due to a heterogeneous structure at a low frequency range. The heterogeneous structure shows a surface fractal structure having a fractal dimension of ca. 2.4.

Alginates↗

Formation of mineralizing osteoblast cultures on machined, titanium oxide grit-blasted, and plasma-sprayed titanium surfaces.

Altering osseous responses at implant surfaces to enhance bone is a current goal of clinical therapy. Cell culture may be used to investigate surface-dependent responses of bone-forming cells. In this report, the ability of primary fetal bovine mandibular osteoblast cultures to form a mineralizing matrix on machined, titanium plasma-sprayed, and titanium oxide grit-blasted surfaces has been compared. Immunohistochemical markers associated with bone formation were used to define the differentiated state of the formed matrix using qualitative light microscopy, and von Kossa staining was used to demonstrate the presence of mineralization within this matrix. Compared to either titanium oxide grit-blasted or machined surfaces, titanium plasma-sprayed surfaces displayed a unique pattern of mineralized matrix formation. Scanning electron microscopy further revealed that each surface accumulated unique organic and inorganic deposits during matrix formation, suggesting that surface-dependent physicochemical and biochemical conditioning of implant surfaces takes place. Surface topographic features of commercially pure titanium substrates can alter cultured osteoblast extracellular matrix formation and mineralization. Similar molecular and cellular assessment of in vivo responses to implant surface topography may contribute to improved engineering of endosseous implants.

Animals↗

Serrated adenoma: a clinicopathological, DNA ploidy, and immunohistochemical study.

AIMS: Serrated adenoma (SA) is a relatively newly defined entity of colorectal neoplasm. In this study, we examined the cell proliferation, DNA ploidy, and clinicopathological features of SA in order to investigate its biological features. METHODS AND RESULTS: We reviewed 10,532 polypectomy specimens of the colorectum obtained from Japanese cases between 1974 and 1998 at Tohoku University Hospital. In total, 193 cases of SA were detected. We first examined clinical features of these cases by reviewing the charts, and then studied cell proliferation using immunohistochemistry of Ki-67 and topoisomeraseIIa, p53 immunoreactivity and DNA ploidy. Results were subsequently compared with those of tubular adenoma (TA) and hyperplastic polyp (HP). Mean size of SA (8.6 +/- 4.6 mm) was significantly larger than those of TA (7.3 +/- 4.6 mm) and HP (5.6 +/- 3.0 mm). More than 80% of SA were protuberant in macroscopic appearance. SA was located predominantly in the sigmoid colon and rectum. Incidences of concomitant carcinoma in HP, SA and TA were 0.4% (1 out of 263), 4.1% (8 out of 193) and 10.3% (809 out of 7838), respectively. Labeling indices for Ki-67 and topoisomeraseIIa in HP, SA and TA were as follows: Ki-67--24.2%, 30.8%, 39.5% and topoisomeraseIIa--15.3%, 16.1%, 23.9%, respectively. In SA, p53 immunoreactivity was detected in the intramucosal carcinoma co-existing with the serrated component. Two out of the ten SA cases examined demonstrated non-diploid patterns of DNA ploidy. CONCLUSION: SA is a distinct colorectal neoplastic lesion with the potential of malignant transformation similar to that of tubular adenoma.

Adenoma↗

Thyroid metastasis from hepatocellular carcinoma as an initial presentation: a case report.

Although metastases to the thyroid are not uncommon at autopsy, most of these lesions are clinically occult. To our knowledge, this is the first report of a case of hepatocellular carcinoma initially presenting as a thyroid mass. Various radiological studies suggested malignant thyroid tumor, and core needle biopsy was performed. Metastasis from hepatocellular carcinoma was histopathologically suspected, and subsequent abdominal CT revealed advanced hepatocellular carcinoma.

Aged↗