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T Kasuga

Publications and source records attributed to T Kasuga.

At least 37 records · Page 2Linked to original sources
PubMed1999

Phylogenetic relationships of varieties and geographical groups of the human pathogenic fungus Histoplasma capsulatum Darling.

The phylogeny of 46 geographically diverse Histoplasma capsulatum isolates representing the three varieties capsulatum, duboisii, and farciminosum was evaluated using partial DNA sequences of four protein coding genes. Parsimony and distance analysis of the separate genes were generally congruent and analysis of the combined data identified six clades: (i) class 1 North American H. capsulatum var. capsulatum, (ii) class 2 North American H. capsulatum var. capsulatum, (iii) Central American H. capsulatum var. capsulatum, (iv) South American H. capsulatum var. capsulatum group A, (v) South American H. capsulatum var. capsulatum group B, and (vi) H. capsulatum var. duboisii. Although the clades were generally well supported, the relationships among them were not resolved and the nearest outgroups (Blastomyces and Paracoccidioides) were too distant to unequivocally root the H. capsulatum tree. H. capsulatum var. farciminosum was found within the South American H. capsulatum var. capsulatum group A clade. With the exception of the South American H. capsulatum var. capsulatum group A clade, genetic distances within clades were an order of magnitude lower than those between clades, and each clade was supported by a number of shared derived nucleotide substitutions, leading to the conclusion that each clade was genetically isolated from the others. Under a phylogenetic species concept based on possession of multiple shared derived characters, as well as concordance of four gene genealogies, H. capsulatum could be considered to harbor six species instead of three varieties.

AIDS-Related Opportunistic Infections↗
PubMed1999

An index for human lens transparency related to age and lens layer: comparison between normal volunteers and diabetic patients with still clear lenses.

OBJECTIVE: The light scattering intensity of normal, clear lenses varies with age and with the localization within the lens. Realizing the biometry of single lens areas together with their relevant light scattering intensity one should be able to calculate an index to express the lens transparency properties of normal human lenses in dependence on age. Performing the same procedure in cases of diabetic patients with still clear lenses it should become possible to obtain an index for the lens transparency properties of lenses under the 'risk factor' diabetes. METHODS: 748 eyes with transparent lenses in 383 healthy individuals and 134 eyes with clear lenses in 70 subjects with diabetes were examined. Scheimpflug slit images of the lens were documented by a Nidek EAS-1000 instrument. Biometry for measuring the distance of the single lens layers from the anterior capsule and densitometry for determining the light scattering intensity of six defined lens layers along the (theoretical) optical axis were performed. The index of the lens transparency properties was calculated using the light scattering intensity of a defined lens layer and its distance from the anterior capsule. RESULTS: Lens thickness and light scattering intensities increased linearly with increasing age in the normal population as well as in the diabetic patients. The densitogram pattern of the light scattering intensities in the defined representative six points was similar in both populations, but in the diabetic group the lens thickness was larger and the light scattering intensities were higher at all ages. CONCLUSION: The index of lens transparency properties calculated with the light scattering intensities of a certain lens area and its distance from the anterior capsule is a useful measure of lens clarity in dependence on age. 'Clear' lenses of the diabetic population show significantly higher indices for the lens transparency properties in all age groups.

Adult↗
PubMed1999

[Epidemiological survey of ocular diseases in K Island, Amami Islands: prevalence of cataract and pterygium].

PURPOSE: An epidemiological survey of ocular disease was performed in a town of the Amami Islands in southwestern Japan. OBJECT AND METHODS: A total of 339 participants over 40 years joined the survey. Among the 339 participants, the lens findings of 602 eyes of 301 subjects were analyzed. RESULTS: The prevalence of lens opacification was 32.0, 54.0, 83.1, 96.9% and 100% among subjects in their 40, 50, 60, 70 s, and over 80 years. Lens opacification over grade II was 4.0, 12.7, 26.2, 60.0% and 83.3%. The cataract type most frequently seen was cortical (96.1%), followed by 48.5% with nuclear opacity and 14.7% with subcapsular type. A high prevalence was seen of pterygium at 25.4%. Although the prevalence of lens opacification was higher in the group with pterygium in their 70 s, no significant difference was noticed in persons in their 40, 50, 60 s, and over 80 years old between the pterygium and non-pterygium groups. CONCLUSIONS: Similarly to the results of a previous survey in Okinawa, Noto, and Hokkaido, the main type of lens opacification was cortical in Amami. The prevalence of nuclear opacification and pterygium was higher than in Noto and Hokkaido, and close to that seen in Okinawa.

Adult↗
PubMed1998

Reconstruction for the brilliance-upgrading project of the Photon Factory storage ring.

Reconstruction of the Photon Factory storage ring (PF ring; 2.5 GeV) is now in progress to provide very brilliant synchrotron radiation to users, i.e. the emittance is being reduced by a factor of five. Components, such as the quadrupole and sextupole magnets, vacuum chambers, beamlines and beam-position monitors, are being replaced by new ones in 16 normal-cell sections of the PF ring. The accelerating cavities, injection systems and control systems are also being replaced. Operation will commence when the improvements are completed on 1 October 1997.

Journal Article↗
PubMed1998

New beam-position monitor system for upgraded Photon Factory storage ring.

Accompanying the brilliance-upgrading project at the Photon Factory storage ring, the beam-position monitor (BPM) system has been renovated. The new system was designed to enable precise and fast measurements to correct the closed-orbit distortion (COD), as well as to feed back the orbit position during user runs. There are 42 BPMs newly installed, amounting to a total of 65 BPMs. All of the BPMs are calibrated on the test bench using a coaxially strung metallic wire. The measured electrical offsets are typically 200 micro m in both directions, which is 1/2-1/3 of those of the old-type BPMs. In the signal-processing system, PIN diode switches are employed in order to improve reliability. In the fastest mode, this system is capable of measuring COD within about 10 ms; this fast acquisition will allow fast suppression of the beam movement for frequencies up to 50 Hz using a global feedback system.

Journal Article↗
PubMed1996

Heterogeneity in intergenic regions of the ribosomal repeat of the pine-blister rusts Cronartium flaccidum and Peridermium pini.

Mixed aeciospore isolates of Cronartium flaccidum and Peridermium pini were obtained from single-tree infections in Britain, Italy and Greece. The 5.8s ribosomal RNA gene and flanking intergenic transcribed spacer regions ITS1 and ITS2 were found to be highly similar between C. flaccidum and P. pini. Within samples heterogeneity was detected at three nucleotide loci in the ITS1 and at four loci in the ITS2 suggesting that several fungal genotypes may occur at a single infection court. The heterogeneity was confirmed by heteroduplex polymorphism analysis of mixed aeciospore products. RFLP of the ribosomal intergenic spacer region 1 (IGS1) amplified from the same templates indicated limited sequence polymorphism in some copies of this repeated locus. Both the sexual and asexual forms of C. flaccidum show evidence of sequence polymorphism in two independent, non-coding regions of the ribosomal gene array. Variation appears to be greater in the sexual form C. flaccidum, than in the monoaecious form P. pini.

Base Sequence↗
PubMed1996

[Methodological study of hemodynamic analysis of lung mass by contrast enhanced dynamic CT].

We investigated a method of analyzing the hemodynamics of the lung mass by contrast enhanced dynamic computed tomography (dynamic CT) to determine the difference in vascular supply between the pulmonary artery and bronchial artery using an experimental model. Our experimental model consisted of two injectors connected to two tubes, representing the pulmonary artery and bronchial artery, which were further connected to a chamber representing the lung mass. Following infusion of contrast medium into each tube with some delay time, dynamic CT scans were performed to obtain time density curves of the two tubes and the chamber. Using the time-density curve of contrast passage, flow rates from the two tubes into the chamber were calculated by the curve fitting method. Calculated values correlated well with the adopted flow rates of fluid from the injectors (r = 0.893) in the experiment. The results indicate our method of individually measuring flow rates of dual-input blood flow, i.e., from the pulmonary artery and bronchial artery, into the lung mass is applicable clinically to determine blood flow by the two arteries supplying the lung mass.

Animals↗
PubMed1995

Long wavelength-middle wavelength cone interaction under no background in the electroretinogram of the cynomolgus monkey.

We recorded electroretinograms from anesthetized cynomolgus monkeys for 30 monochromatic (400-700 nm) full-field stimuli with five different stimulation levels presented without a background light. Waveforms were analyzed by means of principal component analysis to investigate the influence of stimulus intensity on long- and middle-wavelength cone interaction. With increasing levels of stimulus intensity, the middle-wavelength cone system showed a slight peak shift and a noticeable increase in response, while the long-wavelength cone system showed an obvious change in peak wavelength rather than response. In addition, spectral responses in the long-wavelength cone system increased over the red region, whereas they decreased over the yellow region. On the other hand, responses in the middle wavelength cone system increased over the yellow region much more than over the green region. These complicated changes are thought to indicate the induction of long- and middle-wavelength cone interaction by stimulus light.

Adaptation, Ocular↗
PubMed1995

Metastable single-strand DNA conformational polymorphism analysis results in enhanced polymorphism detection.

Single-strand DNA conformational polymorphism (SSCP) makes use of sequence-dependent folding of single-stranded DNA (ssDNA), which alters the electrophoretic mobility of the fragments, to detect sequence differences between closely related molecules. In this study ssDNAs were purified by depletion of the complementary strand and PCR reactants on magnetic M-280-strepavidin beads. It was found that SSCP profiles created by purified ssDNAs differ from the profiles created by more usual SSCP methods. Under some conditions, SSCP profiles using whole PCR reaction products may result from the interaction between residual PCR primers and ssDNAs. We observed that the ratio of conformers revealed by band position and band intensity may vary between the assay techniques and misinterpretation of sequence variants may result. Another observation of this study was the formation of metastable conformational isomers with bead-purified ssDNAs by eliminating the thermal treatment used in conventional SSCP methods. The metastable SSCP (mSSCP) represents a novel and sensitive system for detection of sequence variation between closely related DNAs. The technique used here for the preparation of the purified ssDNAs is potentially useful for automated PCR-SSCP analysis using capillary electrophoresis or other methods.

Autoradiography↗
PubMed1995

[Clinical application of digital TV tomosynthesis to disorders of the wrist and their post-operative evaluation].

The clinical utility of digital TV tomosynthesis was assessed in 13 patients with chronic disorders of the wrist and the first carpometacarpal joints, and a post-operative evaluation was carried out. The disorders included nonunion of the scaphoid in five patients, Kienböck's disease in four, subluxation of the distal radioulnar joint in two, and osteoarthrosis of the first carpometacarpal joint in two. The total time needed to obtain two sets of tomographs of a wrist by digital TV tomosynthesis was about 10 minutes, or approximately one third of the time required with conventional methods. The total radiation exposure in obtaining all tomographs of one direction with digital TV tomosynthesis was less than that in obtaining only one tomograph with conventional methods. Digital TV tomosynthetic images were judged superior to conventional tomographs by four orthopedic surgeons and four radiologists, because tomographic blur was reduced in part by a spatial frequency filter processing. Clinically, digital TV tomosynthesis was very helpful in evaluating nonunion of the scaphoid and Kienböck's disease, especially in their post-operative conditions with metallic fixative devices. Digital TV tomosynthesis was found to be a fast, feasible and inexpensive method with low radiation exposure for evaluating disorders of the wrist.

Adult↗
PubMed1995

[Trial of a small image network system in a radiology department of an university hospital].

This paper describes the construction of an image network system in Shinshu University Hospital, and some of its current issues and advantages. Our discussion is based on our experience with a PACS system. SAIPACS, which was installed in 1990 for use in clinical conferencing and pre- and post-graduate education, and with a new CT and MRI network, which was subsequently introduced in 1993. The SAIPACS interconnects eight digital imaging modalities, including CT, MRI, XTV-DR (including digital tomosynthesis), FCR, nuclear medicine (RI), DSA, US, and a film digitizer (FD), with a workstation. Transmission time from the magnetic disk of each imaging modality to the SAIPACS image disk is not rapid enough. Therefore, we need to select images for transfer that are pertinent to our specific purpose, to complete image transmission within a practically acceptable period of time. The new CT/MRI network is composed of two CT units, two MRI systems, an image processing unit and a Universal Gateway. It provides faster image transmission than the SAIPACS system, because there is no need to reform image data to send them in a reversible compressed form. A versatile network system connected to the SAIPACS and CT/MRI network enables digital image data to be processed and edited and images to be transferred back to SAIPACS for clinical or educational use.

Computer Communication Networks↗
PubMed1995

[123I-MIBG myocardial SPECT in two patients with familial amyloid polyneuropathy].

201T1C1 SPECT and 123I-MIBG SPECT were performed in two patients with familial amyloid polyneuropathy (FAP). Both patients showed normal accumulation of 201T1C1 and no accumulation of 123I-MIBG in the myocardium at the early and delayed images. These results indicate that the patient with FAP-related myocardial change accompanies sympathetic nerve dysfunction. The dysfunction is supposed to be caused by disturbance of re-uptake of MIBG by the terminal ending of the sympathetic nerve (uptake-1) through the amyloid-deposited connective tissue.

3-Iodobenzylguanidine↗
PubMed1994

[Study of X-ray filter and peak kilovoltage in film-screen chest radiographs in regard to detection of simulated pulmonary nodules: comparison between film-screen combination and FCR].

We compared the ability of standard film-screen chest radiographs to detect simulated pulmonary nodules. The radiographs were taken with different X-ray filters and tube voltages. Detection capability was analyzed utilizing receiver operating characteristic (ROC) curves formed from the interpretation of six readers. Nodule detection was slightly better in images obtained with a tube voltage of 135 kVp than with one of 100 kVp (not statistically significant). Approximately equal detection performance was shown by a conventional film-screen system and FCR with three X-ray filter sets: a copper filter backed by aluminium, a tungsten filter backed by yttrium and aluminium, and a lead filter backed by yttrium and aluminium. Results showed less X-ray exposure with the two latter filter sets. Unenhanced FCR images taken with approximately the same X-ray exposure as conventional radiographs showed nearly equal ability to detect the simulated nodules.

Humans↗
PubMed1994

[Micro-wave local area network for radiological image transmission].

Shinshu University consists of five campuses in different locations, a situation that presents some problems in communication. To solve this problem, the Shinshu University Video and Data Network System (SUNS), which includes a high-speed audio-visual transfer function, has been developed and utilized for pre- and postgraduate education, administrative teleconferences, and local telephone (PBX) and Fax services. In 1988, a cooperative group for the study of radiographic image processing was organized, consisting of staff members of Shinshu University Hospital in Matsumoto, the Faculty of Engineering in Nagano (75 km from Matsumoto) and the Faculty of Textile Science and Technology in Ueda (45 km from Matsumoto). The system has been developed with a pair of personal computer (PC)-based interactive image workstations and high-speed digital telecommunication interfaces to the SUNS. A transmission time of 878 kbps has been attained, including the time needed for read/write onto the PC hard disk. Image data thus transferred from the hospital have been utilized for the study of image processing by researchers in the Faculty of Engineering, and the processed images have been sent back to the hospital for evaluation of clinical efficacy of the processing by diagnostic radiologists. This kind of microwave network is a promising alternative for high-speed data transmission for radiological images and their processing.

Computer Communication Networks↗
PubMed1994

[Study of X-ray filter and peak kilovoltage in Fuji Computed Radiography in regard to the detection of simulated pulmonary nodules].

To determine a suitable combination of X-ray filter and tube kilovoltage for Fuji Computed Radiography (FCR), to provide better detection of pulmonary nodules and reduce patient exposure, we compared observer performance with different X-ray filters and tube voltages. Radiographs were obtained with a copper filter backed by aluminium, with a tungsten filter backed by yttrium and aluminium, and with a lead filter backed by yttrium and aluminium, at both 100 kVp and 135 kVp. Observer performance in detecting simulated lung nodules, which were placed on the posterior aspect of a chest phantom, was compared using receiver operating characteristic (ROC) techniques for each combination of the X-ray filter and tube voltage. The results of the study indicated that 1) nodule detection was superior for the images obtained with 135 kVp as compared with 100 kVp; 2) approximately equal detection rates were obtained for the three X-ray filter sets, although results with the tungsten filter were slightly inferior to the other two filters; and 3) the absorbed dose may be reduced by 30% with the use of a lead filter backed by yttrium and aluminium compared with a copper filter backed by aluminium. We conclude that chest radiography with FCR should preferably be conducted with a higher kilovoltage, e.g., 135 kVp rather than 100 kVp, to ensure a higher detection rate of pulmonary nodules and in conjunction with a lead filter backed by yttrium and aluminium to reduce X-ray exposure to the patient.

Filtration↗
PubMed1994

[Cerebral digital tomosynthetic angiography for planning stereotactic biopsy of brain tumor].

We used cerebral digital tomosynthetic angiography for planning the probe trajectory of stereotactic biopsy of brain tumors in four patients. The probe trajectory was basically planned by MRI examinations. However, cerebral digital tomosynthetic angiography demonstrated detailed three-dimensional vascular anatomy around the brain tumors, and therefore was very helpful in revising the planned trajectory when there was a fairly large vessel likely to cross with it.

Adult↗
PubMed1994

Polymerase chain reaction heteroduplex polymorphism analysis by entangled solution capillary electrophoresis.

Heteroduplex DNA polymorphism analysis (HPA) makes use of conformational polymorphisms to alter electrophoretic mobility of fragments and can be used to detect non-restrictable loci. We have developed a novel application of entangled solution capillary electrophoresis (ESCE) to separate heteroduplex and homoduplex DNA molecules. The addition of ethidium bromide and glycerol to the free solution sieving buffer resulted in the improved peak resolution and good reproducibility. Reannealed polymerase chain reaction products could be used directly for mutation screening and with fully automated ESCE the entire HPA may be completed in less than 30 min including sample handling. This technology could provide a rapid and highly efficient way for screening rare mutations among large numbers of individuals.

Base Sequence↗