Biomedical subjects

W Yamada

Publications and source records attributed to W Yamada.

10 recordsLinked to original sources

PubMed2001

The distribution of plantar pressures in American Indians with diabetes mellitus.

The primary purpose of this study was to determine the magnitude and duration of plantar pressures acting on the feet of American Indians with diabetes mellitus. A secondary purpose was to determine whether differences in the range of motion of the ankle and first metatarsophalangeal joints existed between American Indians with and without diabetes. Three groups of American Indian subjects were tested: a control group (n = 20); a group with diabetes but no peripheral neuropathy (n = 24); and a group with diabetes and peripheral neuropathy (n = 21). A floor-mounted pressure sensor platform was used to collect plantar pressure data while subjects walked barefoot. The results indicated that American Indians with diabetes have 1) a pattern of peak plantar pressure similar to patterns previously reported for non-American Indians with diabetes and 2) a reduction in ankle and first metatarsophalangeal joint range of motion in comparison with nondiabetic American Indians.

Adult↗

PubMed2000

Structural basis of the interaction between IgG and Fcgamma receptors.

The binding of multivalent antigen-antibody complexes to receptors for the Fc portion of IgG (FcgammaR) induces the clustering of the FcgammaR and triggers cell activation leading to defence reactions against pathogens. The Fc portion of IgG consists of two identical polypeptide chains which are related to each other by a 2-fold axis and are folded in two structural domains, the C(H)2 domain, near the flexible hinge region of the IgG molecule, and the C(H)3 domain. We studied the interaction in solution between the Fc fragment of mouse IgG2b and the extracellular region of mouse FcgammaRII. We find that one Fc molecule binds one FcgammaRII molecule only. Using NMR spectroscopy, we show that FcgammaRII binds to a negatively charged area of the C(H)2 domain, corresponding to the lower hinge region, and that the binding of FcgammaRII onto one of the two symmetrically related sites on the Fc induces a conformational change in the other site. We therefore propose a model that explains why IgG molecules are unable to trigger FcgammaR-mediated cellular responses spontaneously in the absence of crosslinking by multivalent antigens.

Animals↗

PubMed1998

N-glycan structures of a recombinant mouse soluble Fcgamma receptor II.

N-glycans of a recombinant mouse soluble Fcgamma receptor II (sFcgammaRII) expressed in baby hamster kidney cells were released from glycopeptides by digestion with glycoamidase A (from sweet almond), and the reducing ends of the oligosaccharides were reductively aminated with 2-aminopyridine. The derivatized N-glycans were separated and structurally identified by a three-dimensional high-performance liquid chromatography (HPLC) mapping technique on three kinds of HPLC columns [Takahashi, et al. (1995) Anal. Biochem. 226:139-46]. Eighteen different major N-glycan structures were identified, of which six were neutral (45%), five mono-sialyl (49%), one di-sialyl (4.6%), five tri-sialyl (1.1%), and one tetra-sialyl (0.3%). All N-glycan structures determined were complex type with fucosylation at the N-acetylglucosamine residue of the reducing end, and N-acetylneuraminic acid, when present, was alpha-(2,3)-linked. The existence of a unique structure containing both N-acetylgalactosamine and alpha-(2,3)-N-acetylneuraminic acid residues at the reducing ends, as below, was confirmed by MALDI-TOF mass spectrometry. Carbohydrate sequence [see text]

Animals↗

PubMed1993

Amodal completion as another perception of color-spreading stimuli.

We made a solid three-dimensional object of the Redies-Spillmann figure and found two kinds of completely different phenomena. First, transparent color-spreading was observed in the empty space around the object. Second, another perceptual organization occurred: observers perceived a cross as a cross-shaped slit through which to see, and then they perceived spreading color disappear entirely. They reported an apparent opaque occluding surface which was localized at the same depth as the slit but was in fact the background. They also reported a colored circle which was mostly occluded by the surface with a cross-shaped slit. We interpreted the circle as being amodally completed in the sense described by Kanizsa in 1955. Even when the figure was drawn on a piece of paper, we observed these two perceptions. We examined whether other stimuli causing neon color-spreading lead to reports of the perception for the Redies-Spillmann figure and found that all the stimuli we examined led to reports of the same kind of perception. Interestingly, the shape of color-spreading was the same as that of the amodal completion.

Attention↗

PubMed1985

[The effect of lithium carbonate against leukopenia during systemic chemotherapy in patients with small cell carcinoma of the lung].

To investigate whether lithium carbonate ameliorates the leukopenia and infectious complication that accompany systemic chemotherapy, we studied 19 patients with small cell carcinoma of the lung receiving combination chemotherapy. Eight patients received systemic chemotherapy and lithium carbonate and 11 patients received systemic chemotherapy alone. The mean leukocyte count nadir during chemotherapy was significantly higher in the patients of the lithium group than in the patients of the control group (p less than 0.05). Percentage of infectious complication related to leukopenia was lower in the lithium group than in the control group, although there was no significant difference between these two groups. There was almost no significant side effect except for liver dysfunction in one patient. We therefore believe that lithium carbonate is an effective and safe drug against leukopenia during cytotoxic chemotherapy.

Aged↗

PubMed1985