Akinori Yoshida

A tactile synthesis method using multiple frequency vibrations for representing virtual touch

This paper presents a useful tactile display method that can control multiple tactile sensations such as roughness, pressure, and friction sensations using simple vibratory stimulations. Our concepts are based on two points: frequency range selection for making selective stimulation on different tactile receptors types and timing control of the stimulation in response to hand movements. The selective stimulations were realized by selecting reactive frequencies of vibratory stimulation based on temporal response characteristics of tactile receptors. For representing roughness sensation, vibrating frequencies were modulated in response to hand velocity considered as a temporal coding perception of FA I type receptor. Two reactive frequencies were also selected for representing pressure sensation and friction sensation corresponding to SA I and FA II type receptors respectively. A wearable tactile display using ICPF (ionic conducting polymer gel film) actuators verified our proposed methods. Finally, we conducted a total texture feeling display combined with our methods for roughness, pressure, and friction sensations in a parameterized manner. Comparison with real clothes showed that some combinations of multiple tactile sensations could express texture feels of the expected materials.

Platelet factor 4 mRNA expression in cells from a patient with megakaryoblastic crisis of chronic myelogenous leukemia.

A 61‐year‐old man with Philadelphia chromosome‐positive chronic myelogenous leukemia developed megakaryoblastic leukemia. In the blast phase, his blast cells showed undifferentiated megakaryoblastic characteristics with no α‐granules or demarcation membranes but with detectable platelet peroxidase (PPO) activity and surface glycoprotein (GP) IIb/IIIa. The patient has remained reasonably well for at least 12 months after blastic crisis, and 6‐mercaptopurine alone has been effective in controlling leukocytosis and megakaryoblast proliferation. The expression of mRNA for platelet‐specific proteins, such as GPIIb and platelet factor 4 (PF4), was studied in the patients blast cells by the Northern blot analysis. Both GPIIb and PF4 mRNA were detected in the blast cells. Cytoplasmic maturation occurs later than the synthesis of the surface GP during megakaryocyte maturation. Therefore, PF4 mRNA expression should be a marker of mature megakaryoblasts. The PF4 mRNA expression in megakaryoblastic leukemia may indicate that a patient will have long survival and a good response to chemotherapy.

Refractory anemia terminating in acute megakaryoblastic leukemia (M7).

A 72-year-old man with refractory anemia (RA) developed overt megakaryoblastic leukemia after the course of RA with excess of blasts. The blasts were positive for platelet peroxidase activity and had platelet glycoproteins (GPs) such as GPIIb/IIIa and GPIIIa. The bone marrow biopsy at terminal stage disclosed marked fibrosis. The nature of the megakaryoblasts was investigated. The blasts did not differentiate morphologically into mature megakaryocytes with TPA addition. In vitro colony assay showed the failure of colony-forming unit, megakaryocyte growth in peripheral blood. The pathogenesis of myelofibrosis in our patient is discussed.

Roughness sense display representing temporal frequency changes of tactile information in response to hand movements

We propose a hypothesis on mechanism of roughness perception based on temporal frequency changes of tactile information. Roughness sense can be considered as relative information to the hand velocity. Finite element analysis using human finger model showed that spatial information of the rough surface can be reflected in the temporal frequency changes at the position of tactile receptors. It should be important for roughness sense display to make a vibratory stimulation changing frequencies in response to the hand velocities.

Expression of P62, A Putative Collagen Receptor, on Human Megakaryocytic Leukemia Cells

The expression of glycoprotein (GP)/Ia/Ila and that of P62, a putative collagen receptor defined by IgG in a patient with idiopathic thrombocytopenic purpura (Blood, 69, 1712), was demonstrated on a human megakaryocytic cell line (CMK) using flow-cytometric analysis and Western blotting. Immunological reaction to GPIa/IIa and P62 antigen was detected in about 80% and 50% of CMK cells, respectively. On stimulation with 12–0-tetradecanoylphorbol-13-acetate, the expression of P62 antigen increased markedly, in contrast to that of GPIa/IIa. Immunoblot studies revealed that CMK cells had P62 antigens with molecular weights of 48 kDa and 43 kDa under both reduced and non-reduced conditions. In contrast to the effect of thrombin stimulation, the addition of collagen caused no increase in cytosolic free Ca2+ in CMK cells. We conclude that the lack of response of CMK cells to collagen may result from the presence of dysfunctional collagen receptors.