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Biomedical subjects

H Usami

Publications and source records attributed to H Usami.

At least 19 recordsLinked to original sources
PubMed2005

The influence of liquid crystal display (LCD) monitors on observer performance for the detection of nodular lesions on chest radiographs.

PURPOSE: To access the influence of liquid crystal display (LCD) monitors on the detectability of nodular lesions depicted on chest radiographs by comparing them with a high-resolution cathode ray tube (CRT) monitor. MATERIAL AND METHODS: Ten radiologists interpreted 247 soft-copy images on LCD monitors with pixel arrays of 1,024x1,280, 1,200x1,600, 1,536x2,048 and 2,048x2,560, and a CRT monitor with a pixel array of 2,048x2,560, and were asked to indicate their individual confidence levels regarding the presence of a nodule. These images were chest radiographs with and without a lung nodule from the "Standard Digital Image Database" created by the Japanese Society of Radiological Technology. The luminance distributions of all monitors were adjusted to the same, and the ambient illumination was 200 lux. Observer performance was analyzed in terms of the receiver-operating characteristics. RESULTS: No significant statistical differences in nodule detection performance were found among the four LCD monitors and the CRT monitor. CONCLUSION: The nodule detection performance on the LCD monitors with a spatial resolution higher than a matrix size of 1,024x1,280 was found to be equivalent to that on the high-resolution CRT monitor.

Analysis of Variance↗
PubMed1996

The integrative transformation of Pleurotus ostreatus using bialaphos resistance as a dominant selectable marker.

A plasmid pLC-bar containing the bialaphos resistance gene derived from Streptomyces hygroscopicus between the Lentinus edodes ras gene promoter and priA gene terminator was constructed. When protoplasts of Pleurotus ostreatus were mixed with the plasmid DNA in the presence of polyethylene glycol and CaCl2, bialaphos-resistant colonies were obtained. This indicated that transformation was successful. Southern blot analysis of total DNAs from transformants showed that the introduced plasmid DNA was integrated into the host chromosome and partly rearranged. A plasmid, pLC-GUS, containing the Escherichia coli beta-glucuronidase (GUS) gene under the control of the L. edodes ras gene promoter and priA gene terminator was constructed and introduced into protoplasts of P. ostreatus with pLC-bar by co-transformation. Two of 5 transformants obtained as bialaphos-resistant colonies showed two to twenty times higher specific activity of GUS than the recipient. Southern blot analysis of total DNAs from transformants indicated the presence of the GUS gene only in the two transformants. These results indicated that co-transformation of P. ostreatus was successful, and that the GUS gene was expressed in P. ostreatus. This transformation system will enable us to breed commercial strains of P. ostreatus at the molecular level.

DNA, Fungal↗
PubMed1993

Protein chemotaxonomy of genus Datura: identical amino acid sequence of ferredoxin from two varieties of Datura stramonium.

The complete amino acid sequence of the respective [2Fe-2S] ferredoxins from two varieties of Datura stramonium, D. stramonium var. stramonium and D. stramonium var. tatula, have been determined by automated Edman degradation of the entire Cm-protein and of the peptides obtained by tryptic digestion and CNBr treatment. The ferredoxins from the two plants exhibited identical amino acid sequences, suggesting a very close taxonomic relationship between the two. This result supports the proposal by Blakeslee and others that these plants, at first named by Linnaeus as two distinct species, i.e. D. stramonium L. and D. tatula L., should be considered two varieties of a single species.

Amino Acid Sequence↗
PubMed1990

Inorganic chemical approaches to pharmacognosy. VII. X-ray fluorescence spectrometric studies on the inorganic constituents of crude drugs. (5). The relationship between inorganic constituents of plants and the soils on which they are grown.

Inorganic constituents of the leaves of several kinds of plants growing on different soil types were investigated using energy-dispersive X-ray fluorescence spectrometry. The results can be summarized as follows: (1) Each plant exhibited a characteristic metals profile, even if they were grown on similar soil types. (2) As we would expect, the metals profile of the plant leaves depends on the inorganic constitution of the soil on which it is grown. However, the degree of the influence of the soil types on the metals profile of the plant differs according to the kind of inorganic element: Ca and Cu are almost independent of the soil types, but the Ti and Fe content is dependent upon the soil types. (3) Sr content of plant leaves is closely related to the ratio of Sr to Ca of the soil on which the plants are grown. (4) This information should be helpful in identifying the producing district or original plant of a crude drug by its metals profile.

Japan↗
PubMed1990

[Effects of cusp angle on the adaptation of masticatory function].

The purpose of this study was to elucidate the adaptation in masticatory function by changing the cusp angle of the natural dentition of one person using a metal splint. During each experiment mandibular movements and EMG were recorded during a period of weeks. While chewing raisins as test food, mandibular movements as measured by the lower incisal point displacement were detected three-dimensionally using the Selspot system, and electrical activity of the masticatory muscles was picked up for the anterior temporal and masseter muscles, at the right and left using surface electrodes. The time schedule was composed of three terms: (1) before insertion of the splint, (2) for 20 days after insertion of the splint and then for 30 days after removal (Experiment-1), (3) for 14 days after reinsertion of the splint and then for 7 day after removal (Experiment-2). The measurements were done for the following 7 indices: (1) opening phase, (2) closing phase, (3) cycle time, (4) stopping phase (St), which is the period when the mandible was stationary during occlusal contact, (5) duration of EMG activity, (6) duration of EMG silence, (7) the period of EMG silence (IA), which is the period from the end of EMG activity to the end of the stopping phase. The following results were obtained 1) On changing the cusp angle, there was an increase in cycle time, closing phase, opening phase, duration of EMG activity, and duration of EMG silence, but the stopping phase was less than before insertion of the splint. These 6 indices showed a great variation and became irregular at first. 2) The irregularity of the masticatory function disappeared gradually, and then all indices approached the value before insertion of the splint from day 5 or day 20 at the latest. 3) Scarcely any reaction was detected in IA or in the ratio of cycle time and opening phase throughout the measurement period. 4) The indices of the reinsertion period (Experiment 2) approached the value before insertion more rapidly than the period of the insertion (Experiment-1). And the indices after removal quickly approached pre-insertion values. In short, the indices of the time factor of the masticatory function showed that the effect of changing cusp angle was handled as only disturbances. And once the first adaptation was completed, masticatory function responded more quickly to the same stimulus.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗
PubMed1989

[Effects of articulating paper on mandibular paths in lateral and protrusive excursions].

Mandibular movements in 7 normal dentulous subjects during lateral and protrusive excursions were studied to investigate the effects of the clinical use of articulating paper on mandibular paths. Mandibular movements with or without the intraoral articulating paper (thickness: 35 microns) were detected as the lower incisal point displacement and were recorded three-dimensionally with the Selspot system. The date displayed on the X-Y chart recorder on the selected plane were analyzed quantitatively. 1. The paths of the mandible differed between the outward (from the intercuspal position) and the return (backward to the intercuspal position) movements. In lateral excursions the return path tended to be antero-inferior to the outward path, whereas in protrusive excursions the former tended to be dextro-inferior to the latter. 2. In lateral excursions the return path tended to be less stable than the outward path. In protrusive excursions no significant difference was found between the two paths. 3. In lateral excursions, 21-34% of the movements performed using the articulating paper deviated from the normal paths made without using the paper, and in the case of protrusive excursions, deviation was found in 21-50%. At or near the intercuspal position, the return path showed a greater deviation than the outward path. Near the edge-to-edge position, however, the relationship between these two path was reversed. 4. It is suggested that, when the articulating paper is used, the directions of the movement should be taken into account and sufficient care should be paid in occlusal adjustment because the range of functional movement may be overestimated.

Dental Occlusion↗
PubMed1988

Antitumour effects of streptococcal lipoteichoic acids on Meth A fibrosarcoma.

The antitumour effects of lipoteichoic acids (LTA) extracted from Streptococcus pyogenes were studied in comparison with other streptococcal cellular components. LTA suppressed the tumour growth of both solid- and ascites-type Meth A fibrosarcoma as did the whole cells of S. pyogenes (OK-432). No other cellular components, such as cell wall peptidoglycan, group-specific C-carbohydrate or type-specific M protein, suppressed the growth of Meth A. LTA, but not the other cellular components, induced tumour necrosis factor (TNF) in Propionibacterium acnes-primed mice. LTA had no direct killing effects on Meth A cells. These results indicate that LTA may be an important antitumour component of OK-432 and that one of the antitumour mechanisms by this streptococcal preparation is the induction of TNF.

Animals↗
PubMed1986

Release of tumor necrosis factor (TNF) into mouse peritoneal fluids by OK-432, a streptococcal preparation.

A cytotoxic factor was induced in peritoneal fluid by injection of OK-432 in mice which had been primed with OK-432. Two-step stimulation (priming and eliciting) was always necessary to induce the cytotoxic factor. OK-432-primed mice did not produce soluble cytotoxic factor spontaneously and no cytotoxic activity was detected in the mice treated by a single injection of OK-432 as an eliciting agent. This observation was also confirmed by in vitro experiments. Only when activated macrophages were incubated with OK-432 (or with lipopolysaccharide) was cytotoxin released into medium supernatant. High doses of OK-432 were required to prime mice for the production of cytotoxic factor, whereas a small amount was enough to elicit. The peritoneal cytotoxic factor obtained by OK-432 injection appears to be identical to tumor necrosis factor in the serum for the following reasons: The two factors are similar in mode of cytotoxic action. Both are produced from macrophages. They are similar in physicochemical characteristics. The cytotoxicity of the peritoneal cytotoxic factor was totally abolished by anti-TNF serum.

Animals↗
PubMed1986

Characterization of a cytotoxic factor induced in mouse peritoneal fluid by OK-432.

A cytotoxic factor (peritoneal cytotoxic factor, PCF) was strongly induced by the injection of LPS into the peritoneal fluids of mice which had been previously primed with OK-432. In order to clarify characteristics of PCF, physicochemical and immunological studies were conducted. When incubated with LPS, the macrophages from mice primed with OK-432 induced PCF whereas the lymphocytes did not. These results indicate that PCF is different from lymphotoxin. PCF appears to be quite similar to tumor necrosis factor (TNF) in the serum for the following reasons: The two factors are similar in the mode of cytotoxic action in vitro; both factors have a tumor necrotizing effect when injected into tumor bearing mice; both are produced from macrophages; they are similar in physicochemical characteristics; and the cytotoxic activity of PCF is totally abolished by anti-TNF serum.

Animals↗
PubMed1986

Clearance of endotoxin from blood of rabbits injected with staphylococcal toxic shock syndrome toxin-1.

This study was undertaken to examine some of the properties of staphylococcal toxic shock syndrome toxin 1 (TSST-1) with regard to the clearance of endotoxin from blood. The concentration of endotoxin in blood was measured by using a chromogenic limulus test and modified perchloric acid method. When TSST-1, which produces fever in rabbits, was injected (100 ng/ml or 100 micrograms/ml per kg) intravenously (i.v.) into the animals, no measurable level of endotoxin was detected in the blood. In control animals, which were given 5 micrograms of endotoxin per ml per kg i.v., endotoxin could be detected in the blood at rapidly declining levels. These results suggested that TSST-1 might not lead bacterial endotoxin from other body sites into the blood. When the animals were given TSST-1 (1 to 100 ng/ml per kg) i.v. and then endotoxin (5 micrograms/ml per kg) i.v. 4 h later, endotoxin was detected in the blood at a high level, depending on the dose of TSST-1 injected. These results showed that TSST-1 inhibited the clearance of endotoxin in the blood; this clearance is thought to be mainly done by the reticuloendothelial system. In the animals given TSST-1 (100 ng/ml per kg) and endotoxin (5 micrograms/ml per kg) simultaneously, the endotoxin level in the blood was found to be higher than that in control animals given endotoxin only but lower than that in the animals given TSST-1 and then endotoxin at the same doses.

Animals↗
PubMed1986

[Induction of a cytotoxic factor into the peritoneal fluid (PCF) by OK-432. II. Physicochemical and immunological characteristics of PCF].

A cytotoxic factor (PCF = peritoneal cytotoxic factor) was strongly induced by the injection of LPS into the peritoneal fluids of mice which had been previously primed with OK-432. The similarity in biological activity of PCF, TNF and lymphotoxin led us to study the relationships among the three. When incubated with LPS, the macrophages from the mice primed with OK-432 induced PCF, whereas the lymphocytes did not. These results indicate that PCF is different from lymphotoxin. PCF appears to be identical to Tumor Necrosis Factor (TNF) in the serum for the following reasons: The two factors are similar in their modes of cytotoxic action in vitro. Both factors have a tumor-necrotizing effect when injected into tumor-bearing mice. Both are produced from macrophages. They are similar in their physicochemical characteristics. The cytotoxic activity of PCF was totally abolished by anti-TNF serum.

Animals↗
PubMed1986

[Production of a cytotoxic factor in mouse peritoneal fluid by OK-432, a streptococcal preparation].

A cytotoxic factor was induced by the injection of LPS into the peritoneal fluids of mice which had been previously primed with a streptococcal antitumor preparation, OK-432. No cytotoxic effect on L-929 cells was observed in the peritoneal fluids of mice singly treated with OK-432 or LPS. Various mouse and human tumor cell lines were effectively killed by this peritoneal cytotoxic factor, though normal cell lines were insensitive, which indicates that this factor is not species-specific. The highest level of cytotoxic activity was obtained when LPS was given to mice 5 days after the injection of OK-432. The optimal time for collection of peritoneal fluids for the cytotoxic factor was 2h following the LPS injection. Interferon activity was found to be negative by the plaque reduction test using L-929 cells with vesicular stomatitis virus.

Animals↗
PubMed1986

[Induction of mouse peritoneal cytotoxic factor by OK-432. (3). Comparison between LPS and OK-432 as eliciting agents].

By injection of OK-432, a cytotoxic factor was induced in peritoneal fluids of mice which had been primed with OK-432. Two-step stimulation (priming and eliciting) was always necessary to induce the cytotoxic factor. OK-432-primed mice did not produce soluble cytotoxic factor spontaneously and no cytotoxic activity was detected in the mice treated by a single injection of OK-432 as an eliciting agent. High doses of OK-432 were required to prime mice for the production of cytotoxic factor, whereas a small amount was enough to elicit it. Pathological studies were also conducted in order to clarify whether the mice were safe under the conditions in which PCF had been induced. Moderate liver damage was observed in the mice injected with OK-432 and LPS, whereas no histological change in the liver or spleen was observed in the mice treated with OK-432 alone. These results suggest that OK-432 is a good candidate as an inducer of cytotoxic factor in the peritoneal cavity.

Animals↗