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Biomedical subjects

S Itoh

Publications and source records attributed to S Itoh.

At least 289 records · Page 16Linked to original sources
PubMed1996

Protective effect of magnesium-L-ascorbyl-2 phosphate against skin damage induced by UVB irradiation.

The protective effect of magnesium-L-ascorbyl-2-phosphate (MAP) on cutaneous photodamage such as lipid peroxidation and inflammation induced by ultraviolet B (UVB) exposure (290-320 nm, max. 312 nm) was investigated using hairless mice. When MAP was administered intraperitoneally to mice at a dose of 100 mg of ascorbic acid (AS) per kg body weight base immediately before irradiation (15 kj/m2), the expected increases in thiobarbituric acid reactive substance (TBARS) formation in skin and serum sialic acid, indices of lipid peroxidation and inflammatory reaction, respectively, were significantly reduced. However, the expected decrease in the level of cutaneous AS was unchanged. Similar results were observed for animals given 100 mg of AS-Na per kg body weight before UVB irradiation. When MAP was administered intracutaneously immediately before irradiation, the expected UVB-induced increases in TBARS and sialic acid were again significantly prevented. Ascorbic acid-Na had a less protective effect than intracutaneous MAP administration. The cutaneous AS level was significantly higher in the MAP-treated mice than in the controls, and the UVB-induced decrease in tissue AS was prevented by intracutaneous MAP administration. These results suggest that MAP protects against UVB irradiation-induced lipid peroxidation and inflammation in cutaneous tissue, regardless of the drug administration route. We found, in an in vitro experiment, that MAP was converted to AS as it crossed the epidermis, but that AS-Na did not pass through the epidermis. Furthermore, MAP was also converted to AS in serum. These results suggest that the protective effect of MAP on UVB-induced cutaneous damage is due to conversion of MAP to AS.

Animals↗
PubMed1996

Excimer laser photorefractive keratectomy for patients with contact lens intolerance caused by dry eye.

AIMS/BACKGROUND: To evaluate epithelial wound healing and visual outcome of excimer laser photorefractive keratectomy (PRK) performed on high myopic eyes with contact lens intolerance due to dry eye. METHODS: PRK was performed on two groups of patients with non-Sjogren's dry eye: group A (-6 D to -9.5 D, 11 patients, 17 eyes) and group B (-11.5 D to -19.5 D, 11 patients, 16 eyes) in an attempt to eliminate the use of contact lenses (CL). The intended correction was full in group A and 10 D in group B. RESULTS: Uncorrected visual acuity in group A was better than 20/40 in 12 (80.0%) of 15 eyes at 6 months and in 10 (90.9%) of 11 eyes at 1 year. Fourteen (92.8%) of 17 eyes in group A and four (25.0%) of 16 eyes in group B achieved refraction within plus or minus 1 D of the intended correction at 6 months. Re-epithelialisation was complete in 4 days, and epithelial cell area and permeability returned to the preoperative level within 1 month in all cases. All patients in group A were able to eliminate CL, whereas in group B, one patient needed spectacles for residual myopia and two patients resumed CL use because of regression. One eye with severe subepithelial scar formation and one eye with macular haemorrhage were observed in group B. CONCLUSION: Our results suggest that PRK is effective for patients with high myopia (-6 D to approximately -10 D) and CL intolerance due to dry eye. Further studies are required to improve predictability and to prevent complications in PRK for very high myopia (> -10 D).

Adult↗
PubMed1996

Immunological analysis of organized pneumonia with eosinophilic pleural effusion.

A 73-year-old man developed organized pneumonia with severe right-sided eosinophilic pleural effusion (PE). CD69+ and HLA-DR+ eosinophils in PE were 90 and 31%, respectively, but were undetectable in peripheral blood (PB). CD4+, CD45RA+ (naive) and CD4+, CD45RO+ (memory) cells in PB, PE and bronchoalveolar lavage (BAL) were 10.9, 8.4, 2.5 and 22.7, 38.3 and 16.4%, respectively. CD8+, CD45RA+ (naive) and CD8+, CD45RO+ (memory) cells in PB, PE and BAL were 3.5, 4.7, 1.0, and 8.9, 11.3 and 46.0%, respectively. The concentrations of interleukin-5 (IL-5) and IL-6 in PE were 1,680 and 2,797 pg/ml, respectively; however, these cytokines were undetectable in PB. The patient died 1 month after surgery to remove right thickened pleura. Microscopic findings showed right fibrinous pleuritis and organized pneumonia.

Aged↗
PubMed1996

Tuna muscle peptide, PTHIKWGD, inhibits leukocyte-mediated injury and leukocyte adhesion to cultured endothelial cells.

Tuna muscle-derived angiotensin-converting enzyme inhibitory peptide, PTHIKWGD, inhibited the injury of bovine aorta endothelial cells (BAECs) induced by N-formyl-methionyl-leucyl-phenylalanine-activated polymorphonuclear leukocytes and the adhesion of a leukemia cell line, THP-1 cells, to BAECs stimulated by lipopolysaccharides. It is possible that this peptide directly affects BAECs, protecting them from activated leukocytes.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Increase of cytochrome b mRNA by bis(2-hydroxyethyl) trisulfide in J774A.1 cells.

The effect of a cytotoxic substance (bis(2-hydroxyethyl) trisulfide; BS-1), isolated from Bacillus stearothermophilus UK563, on messenger ribonucleic acid (mRNA) level in mouse macrophage-like J774A.1 cells was investigated by the method of differential display. The treatment of J774A.1 cells with BS-1 led us to detect the inducible gene. The sequence analysis revealed that the gene was identical to mouse mitochondrial cytochrome b. In fact, Northern blot analysis showed that cytochrome b mRNA in J774A.1 cells was increased by BS-1.

Animals↗
PubMed1996

Reaction of adenine with 6-hydroxyestrogen 6-sulfates: model compounds to demonstrate carcinogenesis by estrogen.

To examine carcinogenesis by estrogens, we investigated the reactivity of 6-hydroxyestrogen 6-sulfates. Two epimeric 6-sulfates, pyridinium 3-methoxyestra-1,3,5(10)-trien-6 alpha-yl sulfate (1) and its 6 beta-isomer (2), were synthesized as model compounds and reacted with adenine under mild conditions to give two common products in the ratios of approximately 3:1 and 5:1, respectively. The major product was identified as N6-[3-methoxyestra-1,3,5(10)-trien-6 beta-yl] adenine (10), accompanied with its 6 alpha-isomer (9), by comparison with synthetic specimens. These results imply that, in the metabolism of naturally occurring estrogens, hydroxylation at the C6-position and subsequent sulfoconjugation of the benzylic hydroxyl group may produce sulfates which react with DNA to initiate carcinogenesis.

Adenine↗
PubMed1996

Lack of immunoreactivity for myoglobin in skeletal muscle of acute stroke patients.

Sternothyroid muscle biopsy specimens, obtained during tracheostomies from 15 patients with acute stroke and respiratory failure, were examined immunohistochemically to immunoreactivity to myoglobin (Mb). A marked decrease or lack of Mb immunoreactivity in association with hyaline degeneration was observed in 0.8 to 44.4% of the muscle fibers on both the paretic and non-paretic sides of all patients. The percentages of negative staining for Mb were less than 3.1% in 5 patients with acute respiratory failure due to causes other than stroke. The pattern and incidence of attenuated Mb immunoreactivity in the muscle fibers was found to be distinctively different in the two patients groups. In one group of 5 patients, a large number of muscle fibers (24.8 +/- 15.6%) had no Mb staining and were clearly bordered and grouped. In another 10-patient group, only a limited number of muscle fibers (3.3 +/- 2.5%) had no staining for Mb and these fibers were scattered. Four patients in the former group had catastrophic outcomes, while all the patients in the latter group survived. Ischemia, produced by an increase in catecholamines, and the consequent vasoconstriction, rather than hypoxemia seemed to be the cause of the negative immunoreactivity for Mb in the group pattern. In contrast, hypoxemia may have caused the scattered pattern of negative Mb immunoreactivity. It was concluded that negative immunostaining for Mb in muscle fibers represents a common and characteristic complication in acute stroke patients.

Acute Disease↗
PubMed1996

Titration of human cytomegalovirus (HCMV) DNA in urine by combined use of PCR and microplate hybridization in a renal transplant patient with HCMV pneumonitis.

We titrated human cytomegalovirus (HCMV) DNA in urine specimens obtained from 14 healthy individuals and a renal transplant patient with HCMV pneumonitis by modifying the method for titration of varicella-zoster virus DNA previously described (1,2). Of 14 HCMV seropositive healthy individuals, 13 had HCMV DNA under the detection limit of 10(2.0) copies/ml, whereas one person had 10(2.0) copies/ml. The viral DNA in urine samples was at a low level in healthy individuals with latent infection. In a case with HCMV pneumonitis after renal transplantation, the amount of HCMV DNA in urine gradually increased from the level under 10(2.0) copies/ml and reached a peak of 10(4.7) copies/ml one month prior to the manifestation of pneumonitis. It, thereafter, decreased with the course of clinical remission, and finally settled at under 10(2.0) copies/ml. Serial titrations of HCMV DNA in urine specimens proved to be useful in identifying recipients at risk of developing active HCMV infection after renal transplantation and as a guide for treatment of patients.

Cytomegalovirus↗
PubMed1996

Frequency specificity of 80-Hz amplitude-modulation following response.

The usefulness of 80-Hz amplitude-modulation following response (AMFR) detected by phase coherence to predict the hearing threshold during sleep was evaluated in 90 ears of 53 children with hearing impairment. The threshold of 80-Hz AMFR at carrier frequency of 1,000 Hz and the threshold of auditory brainstem response (ABR) elicited by 1,000 Hz tone pips in children during sleep were compared with behavioral hearing threshold, which was determined by standard pure-tone audiometry or play audiometry. In 12 ears of 12 children with various patterns of hearing impairment, 80-Hz AMFR at different carrier frequencies were examined, and the threshold pattern was compared with the pure-tone audiogram to investigate the frequency specificity of 80-Hz AMFR detected by phase coherence. The mean and standard deviation of the difference between 80-Hz AMFR and pure-tone thresholds was 4.3 and 12.1 dB, respectively, and that between ABR and pure-tone thresholds was 6.6 and 14.2 dB, respectively. The threshold patterns of 80-Hz AMFR very closely resembled the corresponding audiogram patterns in all types of hearing impairment. The measurement of 80-Hz AMFR in children during sleep thus appeared to be more accurate in hearing prediction than that by ABR elicited with tone pips and to have a good frequency specificity.

Adolescent↗
PubMed1996

Structural determinants of substrates for the prostaglandin transporter PGT.

We recently identified a broadly expressed transporter, PGT, that transports primarily prostaglandins E2 and F2 alpha (PGE2 and PGF2 alpha). In the current study, we examined the structural determinants of potential PGT substrates in detail. Rat PGT was transiently expressed in HeLa cells, the timed uptake of tracer PGE2 was determined in the presence of various concentrations of unlabeled prostanoids; and the resulting inhibitory constants (Ki) were determined by curve-fitting. PGE2 and PGF2 alpha, both known to be transported, had similar affinities for PGT (Ki = 49-50 nM). The strongest interaction (Ki = 13-19 nM) was obtained with prostanoids lacking the 9- or 11-position oxygen groups. A relatively high affinity was also obtained for the bicycloendoperoxides U44069, PGH2, and U46619 (Ki = 29-39 nM). However, a radioactive representative from this group, U46619, was not transported. Structural modifications that produced a moderately reduced affinity relative to that of PGE2 (Ki = 56-286 nM) included reduction in C5 = C6, the addition of a benzene group at position C18, and isomerization at the C8 position. In complementary studies, tracer isoprostane B-iso-PGF2 alpha was found to be transported at approximately 13% the rate of tracer PGE2. Substantially weaker interaction (Ki = > 700 nM) was seen when the 1-position COO- anionic group was neutralized or when the 15(S)-OH group was changed to 15(R)-OH or to 15-keto. These results with the cloned rat PGT are very similar to those previously reported in the in vitro perfused rat lung and indicate that PGT probably represents the predominant route by which certain prostanoids, including F2 isoprostanes, are transported across plasma membranes.

Animals↗
PubMed1996

[Fundamental study for lung-cancer screening by helical CT. First report: evaluation of radiation dose and image quality using a phantom].

In a fundamental study on the early detection of lung cancer by helical computed tomography (CT), we evaluated the effect of scanning parameters on radiation dose and image quality using a phantom. The exposure dose at the center of the gantry and the absorbed dose at the center of an acrylic phantom changed linearly in proportion to tube current. On the other hand, as the table feed speed increased, the rate of reduction in these doses became smaller. While the change in CT value of an acrylic sphere in the longitudinal axis, the difference in CT value between an acrylic sphere and styrofoam in the horizontal plane and the CT profile curve of an acrylic sphere in the horizontal plane did not change according to tube current, an increase in table feed speed brought about the degradation of these items. In conclusion, reduction of the tube current in helical scanning is able to reduce radiation dose without causing a significant change in image quality, but an excessive increase in table feed speed does not reduce radiation dose effectively and is associated with degradation in image quality.

Humans↗
PubMed1996

[Fundamental study of lung-cancer screening by helical CT: second report: evaluation of CT images using normal volunteers].

In order to examine the use of helical computed tomography (CT) in lung cancer screening, we evaluated the effects of tube current and table feed speed on image quality. CT images of normal volunteers, which were scanned under various tube currents (150mA, 100mA, 50mA) and various table feed speeds (15mm/sec, 20mm/sec, 25mm/sec, 30mm/sec), were visually evaluated by experienced diagnostic radiologists. The images were not affected by decreasing the milliamperage. However, as table feed speed increased, images were evaluated as significantly worse. Particularly, since the degradation of the images scanned at greater than 25mm/sec was remarkable, they were judged to be unacceptable for detection of the abnormality. In conclusion, a tube current of less than 50mA and table feed speed of less than 20mm/sec are suitable in the application of helical CT for lung cancer screening.

Adult↗
PubMed1996

Management conditions during dialysis therapy influence the occurrence of complications after renal transplantation?

We investigated whether the management condition of patients during dialysis therapy has an influence on the occurrence of complications after renal transplantation. Thirty-one patients who underwent renal transplantation were investigated: thirteen received kidneys from living related donors and 18 received cadaveric transplants. The relations between weight gain ratio, cardiothoracic ratio (CTR) and blood pressure during dialysis and the rate of episodes of acute rejection or infection after renal transplantation were analyzed. The rate of acute rejection tended to be higher among patients whose CTR was less than 45% than in those whose CTR was 45% or more. There was no relation found between the rate of infection after transplantation and weight gain ratio. CTR, or blood pressure during dialysis therapy. These results suggest the possibility that the management condition of patients during dialysis therapy influences the rate of acute rejection after these patients undergo renal transplantation.

Adolescent↗
PubMed1996

[Helical CT for lung-cancer screening: third report: fundamental study for ultralow-dose CT by application of small tube current and filter].

In order to develop ultra-low-dose helical CT for lung cancer screening, the effect of reduction of the tube current to 20mA and application of a 10mm thick aluminium filter upon radiation dose and image quality was evaluated with a phantom. Exposure dose at the center of a gantry and absorbed dose at the center of an acrylic phantom at 20mA with the filter were 15% and 29% of the dose at 50mA without the filter, respectively. For reduction of absorbed dose, reduction of the tube current was more useful than application of the filter. Image noise at 20mA with the filter was double that at 50mA without the filter. Neither reduction of the tube current nor application of the filter changed full width at half maximum on section sensitivity of the Z-axis. Although reduction of the tube current did not affect the difference in CT values between an acrylic sphere and styroform, application of the filter caused a reduction of 4.5% in the difference in CT values. Neither reduction of the tube current nor application of the filter affected the contrast resolution of the high-contrast phantom; however, that of the low-contrast phantom deteriorated. Although improvement of the filter and evaluation of clinical images are necessary, reduction of the tube current to 20mA and application of the aluminium filter appear to be a promising method for ultra-low-dose helical CT of the lung.

Filtration↗
PubMed1996

Effects of toborinone on myocardial oxygen consumption in pacing-induced heart failure dogs.

The effects of a novel positive inotropic agent, toborinone ((+/-)-1-[3,4-dimethoxy-benzylamino)-2-hydroxypropoxy]-2(1H)-quinolinone , CAS 128667-95-8, OPC-18790, on myocardial oxygen consumption were examined in pacing-induced heart failure dogs. Ten dogs were ventricularly paced at 260 beats/min for 10 days to induce heart failure. Five of them were controls and the remaining five were given toborinone. Dogs were anesthetized with halothane, and cardiac functions, hemodynamics and myocardial oxygen consumption were measured. The peak of the first derivative of left ventricular pressure (LV dP/dtmax), cardiac output (CO) and mean blood pressure (mBP) were significantly decreased, and left ventricular end-diastolic pressure (LVEDP), mean right atrial pressure (mRAP), pulmonary capillary wedge pressure (PCWP) and mean pulmonary arterial pressure (mPAP) were also significantly increased after 10 days of rapid ventricular pacing. Toborinone (5 and 10 micrograms/kg/min) dose-dependently increased LV dP/dtmax, coronary blood flow (CBF) and CO and decreased LVEDP and systemic vascular resistance (SVR) without increasing myocardial oxygen consumption in the pacing-induced heart failure dogs. These results suggest that toborinone may be useful for the management of chronic and congestive heart failure.

Animals↗
PubMed1996

[Helical CT for lung-cancer screening: fourth report. Detectability of pulmonary lesions].

The detectability of various abnormal findings in helical screening CT(HSCT) with low-dose and single-breath-hold scanning of the lung was examined using conventional CT as a gold standard. In 75 patients, HSCT was obtained with scanning parameters of 120kVp, 50 mA, 10 mm-collimation. 20 mm/second and 1 sec/rotation. Conventional CT was obtained with 150 mA and 10 mm-slice contiguous scanning HSCT depicted 141 of 159 focal lesions in nodules and masses (65 of 69 lesions more than 5mm in size), 44 of 47 in infiltrative lesions, 11 of 11 in reticular lesions and 23 of 39 in bullae and blebs. There were only 3 false positive lesions in nodule and mass. Sensitivity, specificity and accuracy of HSCT for diffuse lesions were 100% (11/11), 95% (61/64) and 96% (72/75) for fibrotic change and 75% (9/12), 100% (63/63) and 96% (72/75) for emphysematous change, respectively. Since the detectability of HSCT was good for abnormal findings, showing increased attenuation in comparison with the lung parenchyma, it was considered to be a promising method for lung-cancer screening.

Adult↗
PubMed1996

Molcecular cloning of human antizyme cDNA.

We have cloned the cDNA encoding the human ornithine decarboxylase antizyme from a 5'-stretch cDNA library of human B-cell lymphoma Daudi. The cloned human antizyme cDNA fragment consists of 1063 bp, has 80% homology to the rat antizyme cDNA, but shows almost no homology to the E. coli antizyme gene. Northern hybridization analysis shows that this gene is expressed in a number of human cell lines with an estimated mRNA transcript size of about 1.1 kb. The size of the mRNA suggests that the cloned cDNA fragment probably represents the full length of human antizyme mRNA transcript. Comparison of the human and rat antizymes demonstrates that they are highly conserved at both nucleotide and peptide levels.

Amino Acid Sequence↗