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Biomedical subjects

I Tsuda

Publications and source records attributed to I Tsuda.

At least 19 recordsLinked to original sources
PubMed2002

Flow cytometric analysis of platelet activation under calcium ion-chelating conditions.

Platelet activation and aggregation results in factitious counting and sizing in routine haematology testing. In this study, the possibility of platelet activation in anticoagulated solutions was examined. Whole blood was examined using an automated counter and a flow cytometer before and after strong vortex agitation. Blood treated with ethylenediaminetetraacetic acid (EDTA) exhibited platelet activation both pre- and postagitation but activated platelets did not cause platelet aggregation. With sodium citrate, platelets were only minimally activated both pre- and postagitation. Heparin-treated blood exhibited minimal platelet activation preagitation, but agitation resulted in strong platelet activation and aggregation. Platelet size was increased by agitation in blood with EDTA and with sodium citrate, in association with significant increases in mean platelet volume (MPV) and platelet distribution width (PDW), but MPV and PDW were significantly higher in EDTA solution than in sodium citrate solution. Change in platelet size was observed even in the presence of EDTA, indicating that careful sampling and processing are needed in the collection of specimens. Specimens obtained from patients with EDTA-dependent pseudothrombocytopenia exhibited the same level of activation as controls, although platelets exhibited aggregation in such specimens. In conclusion, platelet activation involving platelet size change can occur in the absence of calcium ions in blood treated with EDTA.

Anticoagulants↗
PubMed2001

Fractal encoding in a chaotic neural network.

We analyze a model of a chaotic neural network consisting of three neurons, namely a chaotically forcing neuron and two neurons comprizing a stable response system with a contraction mapping property, for digital encoding with chaotic dynamics. We show that dynamics of the chaotically forcing neuron is embedded in the form of a code sequence on a fractal attractor of the two-neuron response system. We consider the relation between the state transition of the chaotically forcing neuron and the hierarchical fractal structure on the attractor in the state space of the contracting system. We also report hardware implementation of the presented model with an analog electronic circuit to investigate the fractal attractor of the chaotic neural network as a realistic system.

Journal Article↗
PubMed2001

Primary lung cancer occurring concomitantly with the cicatrized and calcified ova of a parasite: report of a case.

We report herein a rare case of primary lung cancer that occurred concomitantly with the calcified ova of a parasite. A 58-year-old man was referred to our department after a pulmonary abnormal shadow had been seen on a chest X-ray done at mass screening. A transbronchial lung biopsy (TBLB) revealed the calcified ova of a parasite. Because the possibility of concomitant lung cancer could not be ruled out, a lung biopsy was taken via video-assisted thoracic surgery (VATS). The pathological diagnosis was squamous cell carcinoma, and a left upper lobectomy was serially performed through a posterolateral thoracotomy. The patient recovered uneventfully and has remained in good health without any sign of recurrence for over 9 months. Following this case report, we review three other cases of this unusual disease combination documented in the literature.

Calcinosis↗
PubMed2001

Toward an interpretation of dynamic neural activity in terms of chaotic dynamical systems.

Using the concepts of chaotic dynamical systems, we present an interpretation of dynamic neural activity found in cortical and subcortical areas. The discovery of chaotic itinerancy in high-dimensional dynamical systems with and without a noise term has motivated a new interpretation of this dynamic neural activity, cast in terms of the high-dimensional transitory dynamics among "exotic" attractors. This interpretation is quite different from the conventional one, cast in terms of simple behavior on low-dimensional attractors. Skarda and Freeman (1987) presented evidence in support of the conclusion that animals cannot memorize odor without chaotic activity of neuron populations. Following their work, we study the role of chaotic dynamics in biological information processing, perception, and memory. We propose a new coding scheme of information in chaos-driven contracting systems we refer to as Cantor coding. Since these systems are found in the hippocampal formation and also in the olfactory system, the proposed coding scheme should be of biological significance. Based on these intensive studies, a hypothesis regarding the formation of episodic memory is given.

Brain↗
PubMed2001

A centrifuge-less plasma separation method from whole blood anticoagulated with EDTA-2K for the use of clinical laboratory tests.

In the modern medical laboratory system, simple and rapid processing of specimens are required. In the current system with the transportation line, its centrifugation part would disturb smooth flow of the testing because it needs much time for the centrifugation. To solve the problems, a serum separation method was tried for the whole blood specimen using poly-L-lysine, concanavalin A and phyto-hemoagglutinin. Ploy-L-lysine with molecular weight 130,000 to 210,000 in a final concentration of 0.1% could accelerate blood sedimentation, although its supernatant contaminated platelets. Concanavalin and phytohemoagulutinin could accelerate the sedimentation and obtained plasma, but the method could yield enough amount of supernatant by 1 hour standing. As the purpose of this study is to develop a centrifugeless method, a sieve method using a steel mesh and a magnet was applied to the mixture of EDTA blood, red-cell adhesives and thrombin. The method was unique to separate plasma, but the yield was not so high and chemistry data were not fitted with serum data in some of tests. Thus, the trial would be a new technology, but it was judged that some further improvement will be needed technically.

Anticoagulants↗
PubMed2000

Availability of Nagarse for DNA analysis as a substitute for proteinase K.

The availability of Nagarse, a protease, as a substitute for proteinase K for digestion of leukocytic or bacterial DNAs was studied. The amount and purity of DNAs extracted from leukocytes and several bacterial strains with Nagarse were compared with those of DNAs treated with proteinase. Nagarse exhibited the same behavior as proteinase K in digesting leukocytes, and it could also be used for bacterial digestion for physical mapping of genomic DNA by biased sinusoid field gel electrophoresis. Nagarse was thus comparable to proteinase K for use in biochemical experiments. The principal advantage of Nagarse is that it is inexpensive, unlike proteinase K, and our findings indicated that Nagarse is very useful as a substitute for proteinase K for the DNA study.

Adult↗
PubMed1999

Effects of heparin on polymerase chain reaction for blood white cells.

Polymerase chain reaction (PCR) has been used with increasing frequency to diagnose infectious and genetic diseases. In this study, the effects of heparin on PCR were investigated, because heparinized blood may sometimes be used in PCR studies. HLA-DQA1 gene amplification was used as a model. PCR was clearly interfered with when heparinized blood was used as a source of template DNA, and the degree of interference was affected by the following three factors; (1) type of Taq DNA polymerase; (2) leukocyte count in blood; and (3) concentration of heparin contained. When additional tests were conducted with additions of definite heparin concentrations to a PCR reaction mixture, specimens with large amounts of DNA tended to exhibit less interference by heparin. The addition of > or = 0.1 to 0.0016 U of heparin per reaction mixture (50 microl) suppressed DNA amplification in a dose-dependent fashion. We therefore concluded that much care should be taken when heparinized blood is used as a PCR material.

Adult↗
PubMed1999

A new direction in automated laboratory testing in Japan: five years of experience with total laboratory automation system management.

The introduction of integrated laboratory systems has proceeded rapidly in Japan in these 15 years, but they require large initial investment for installation and do not always succeed in reducing laboratory cost. We also experienced three major events that taught us that total laboratory systems are not always effective: these were an earthquake, a nerve gas attack, and an outbreak of food poisoning. Political changes in the national health care system in Japan have forced the cutting of expenses for laboratory testing. In this context, cost-effective laboratory testing has been considered, and many hospitals have replaced total laboratory systems with small laboratory systems. Our University Hospital introduced a mini-lab system consisting of compact instruments to increase laboratory efficiency, and we have begun point-of-care testing education for medical students. This combination enables rapid and convenient testing, and is responsive to the political changes in the Japanese health care system.

Automation↗
PubMed1999

Automated enumeration of cellular composition in bone marrow aspirate with the CELL-DYN 4000 automated hematology analyzer.

The present study was designed to evaluate the automated analysis of bone marrow aspirates with the CELL-DYN 4000 (CD4000) hematology analyzer. Bone marrow aspirates were diluted twice with phosphate-buffered saline and assayed with the CD4000. The percentages of subpopulations including lymphocytes, neutrophils, and erythroblasts were obtained with the CD4000, and as a reference, differential counts by microscopic observation of May-Grünwald-Giemsa-stained films of bone marrow aspirate were performed (n = 48). Significant correlations (p < 0.0001) between the results with the two methods were obtained for total nucleated cell count, lymphocytes, neutrophils, erythroid cells, and the myeloid/erythroid ratio. The present method can provide quantitative data of bone marrow aspirate and will be useful in bone marrow screening.

Biopsy, Needle↗
PubMed1999

Country reports from Japan: external quality assessment scheme in Japan.

Several external quality assessment schemes (EQAS) have been conducted in Japan. Results obtained from nation-scale EQAS reveal the current quality of laboratory testing in each laboratory. The largest nation-scale EQAS in Japan is that conducted by the Japan Medical Association. The numbers of participants and of items evaluated have increased in EQAS by JMA over its history of 32 years. Improvement in inter-laboratory differences has been observed for most items in EQAS in recent decades. In 1998, about 2,500 laboratories from throughout the country participated in this surveillance, and 47 items were evaluated. The coefficient of variations for the group of all participants was less than 5% for about one third of all test items. On the other hand, very high variations over 20% were observed for 6 items. Also, inter-method differences exist for many items, which may be or may not be related to matrix effects. Retrospective evaluation of all EQAS data suggests that there is still room for improvement in inter-laboratory differences.

Bacteriological Techniques↗
PubMed1999

Incidence of abnormalities in laboratory tests found in surveillance of adults over 40 years of age.

National health check-up systems have been used for 5 years in Japan for adults who are over 40 years of age. As part of a national project, Osaka prefecture is also conducting a program for health check-up testing and cancer screening for this age group. This surveillance revealed that incidence of obesity, hypertension, cholesterolemia, albuminuria, or abnormal ECG was high. Analysis of surveillance results should contribute to understanding the present status and recent trends in diseases in the aged. With continuation of this surveillance for a number of years, trends in life-style related diseases in Japan should be detectable.

Adult↗
PubMed1999

Current status of liver function tests in Japan.

Inter-laboratory variations in data obtained from surveillance in Japan were studied. The items evaluated were related to liver function and were as follows: total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (gamma-GT), cholinesterase (CHE), lactate dehydrogenase (LD), alkaline phosphatase (ALP) and hepatitis markers. Inter-laboratory coefficients of variations for bilirubin, AST and ALT were acceptable, being less than 10%. but higher variations were found for thle other enzyme assays. Detection of hepatitis markers was acceptable. However. even for parameters with lower inter-laboratory variation, differences in obtained values among different reagents or methods still existed. Thus, standardization will be needed for laboratory data in Japan, and this will contribute to international standardization in laboratory medicine in the future.

Biomarkers↗
PubMed1999

External quality control results for hormones, tumor markers and CRP testing.

Most hormones, tumor markers, C-reactive protein, and rheumatoid factor (RF) are measured immunologically. Immunological methods based on the antigen-antibody reaction have certain specific problems, including their principle of determination, character of antibodies used, reaction conditions, and others. Free thyroxine (FT4) and thyroid stimulating hormone (TSH), as well as alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), prostate antigen, carcinoantigen 19-9 (CA 19-9), and CA 125 are very commonly measured in the routine medical laboratory. Authentic materials can be obtained for hormones and CRP, and efforts to improve quality control and standardization have been made for years. Results of surveillance for FT4, TSH, and AFP were not poor, but inter-laboratory differences for CEA, CA 19-9, and RF were not insignificant.

Biomarkers, Tumor↗
PubMed1999

Icsh activities and Asia.

The International Council for Standardization in Haematology (ICSH), an international organization promoting international agreement on hematological testing, is now restructuring to strengthen its activities. In Asia, a diversity of testing methods exists and the resulting testing levels make it difficult to compare test results internationally among Asian countries. Fortunately, the ICSH is considering regionalizing its organization to 5 sub-societies to increase its activity, and we have been able to establish a new society, ICSH-Asia, under the ICSH umbrella.

Asia↗
PubMed1998

A convenient method of DNA extraction from blood anticoagulated with EDTA.

Surplus blood often remains after routine clinical tests using EDTA-anticoagulated samples. To use this blood for DNA analysis, we isolated white cells by adherence to polyethylene terephthalate fibers, which could be stored for several weeks transported by mail after methanol fixation. DNA yield was sufficient and correlated with white cell count. Extracted DNA was free of hemoglobin contamination and durable to polymerase chain reaction and enzyme digestion, which yielded products visualized as well-separated bands on electrophoresis. We found our method to be practical for the routine clinical laboratory.

Adult↗