[Synthesis of pyrrolidine derivatives. 3. Synthesis of methyl ketone compounds of kainic acid. (I)].
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Acids↗
Biomedical subjects
K Murayama
Publications and source records attributed to K Murayama.
[Synthesis of pyrrolidine derivatives. IV. Synthesis of methyl ketone compounds of kainic acid. (2)].
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Acids↗
Sensitive detection of near-infrared fluorescent dyes using high-performance liquid chromatography with peroxyoxalate chemiluminescence detection system.
The highly sensitive detection of four near-infrared (near-IR) fluorescent dyes, methylene blue, pyridine 1, oxazine 1 and 3,3'-diethylthiadicarbocyanine iodide (DTDCI) by high-performance liquid chromatography (HPLC) with post-column peroxyoxalate chemiluminescence (PO-CL) detection utilizing bis(4-nitro-2-(3, 6,9-trioxadecyloxycarbonyl)phenyl) oxalate (TDPO) and hydrogen peroxide was examined. The detection limits for methylene blue, pyridine 1, oxazine 1 and DTDCI were 120, 27, 31, 0.19 fmol on-column at a signal-to-noise ratio of 2, respectively. The sensitivity for DTDCI was 250 times that obtained by HPLC with the conventional fluorescent detection.
Chromatography, High Pressure Liquid↗
Enantiomeric separation of d-/l-norepinephrine and -epinephrine by high-performance liquid chromatography with a beta-cyclodextrin type chiral stationary phase.
Enantiomeric separation of d-/l-norepinephrine (NE) and d-/l-epinephrine (E) was investigated with various mobile phases by high-performance liquid chromatography using a beta-cyclodextrin type chiral stationary phase as a chiral column. The mobile phase of 2.5 M phosphate buffer (pH 3.0) gave separation factors (alpha s) of 1.04 and 1.06 for NE and E, respectively.
Buffers↗
Temporal frequency characteristics of retinitis pigmentosa obtained by pattern visual evoked cortical potential to checkerboard stimuli.
We examined temporal frequency curves by pattern visual evoked potential in 28 eyes suffering from retinitis pigmentosa (RP). The peak latency of the P100 component was 110.3 +/- 3.0 msec (S.E.), which was not significantly different from the 110.2 +/- 0.8 msec (S.E.) obtained from 60 normal controls. The P100 amplitudes of whole reversal frequencies, however, were decreased in patients with RP (p less than 0.05), especially at lower frequencies. We thought this phenomenon was useful for determining central visual function in patients with RP.
Adolescent↗
Color-coded pattern suppresses visual evoked cortical potentials and electroretinograms.
We developed a new visual stimulating system for recording visual evoked cortical potentials and electroretinograms. The stimulus was a color checkerboard, in which each check kept its chromaticity but changed its luminance with its corresponding check. Color-coded pattern stimuli using red and green checks did not produce visual evoked cortical potentials, while yellow checks produced clear responses in a normal subject. Moreover, five color stairs from red and green to yellow showed only that the more colors are different, the smaller the visual evoked cortical potentials become. In addition electroretinogram recordings indicated that color-coded patterns behave in the same way as in visual evoked cortical potentials. The mechanism that causes the small color visual evoked cortical potentials may already be present in the retina. Color perception may be able to induce a suppression of responses for luminance contrast that appears to be formed already in the retina. Retinal responses were affected whether the stimulus field was color coded or not. Pattern electroretinograms appear to be more than the sum of local on and off responses.
Adult↗
Push-pull model of the primate photopic electroretinogram: a role for hyperpolarizing neurons in shaping the b-wave.
Existing models of the primate photopic electroretinogram (ERG) attribute the light-adapted b-wave to activity of depolarizing bipolar cells (DBCs), mediated through a release of potassium that is monitored by Müller cells. However, possible ERG contributions from OFF-bipolar cells (HBCs) and horizontal cells (HzCs) have not been explored. We examined the contribution of these hyperpolarizing second-order retinal cells to the photopic ERG of monkey by applying glutamate analogs to suppress photoreceptor transmission selectively to HBC/HzCs vs. DBCs. ERGs of Macaca monkeys were recorded at the cornea before and after intravitreal injection of drugs. Photopic responses were elicited by bright 200-220 ms flashes on a steady background of 3.3 log scotopic troland to suppress rod ERG components. 2-amino-4-phosphonobutyric acid (APB), which blocks DBC light responses, abolished the photopic b-wave and indicated that DBC activity is requisite for photopic b-wave production. However, applying cis-2,3-piperidine dicarboxylic acid (PDA) and kynurenic acid (KYN), to suppress HBCs/HzCs and third-order neurons, revealed a novel ERG response that was entirely positive and was sustained for the duration of the flash. The normally phasic b-wave was subsumed into this new response. Applying n-methyl-dl-aspartate (NMA) did not replicate the PDA+KYN effect, indicating that third-order retinal cells are not involved. This suggests that HBC/HzC activity is critical for shaping the phasic b-wave. Components attributable to depolarizing vs. hyperpolarizing cells were separated by subtracting waveforms after each drug from responses immediately before. This analysis indicated that DBCs and HBC/HzCs each can produce large but opposing field potentials that nearly cancel and that normally leave only the residual phasic b-wave response in the photopic ERG. Latency of the DBC component was 5-9 ms slower than the HBC/HzC component. However, once activated, the DBC component had a steeper slope. This resembles properties known for the two types of cone synapses in lower species, in which the sign-preserving HBC/HzC synapse has faster kinetics but probably lower gain than the slower sign-inverting G-protein coupled DBC synapse. A human patient with "unilateral cone dystrophy" was found to have a positive and sustained ERG that mimicked the monkey ERG after PDA+KYN, indicating that these novel positive photopic responses can occur naturally even without drug application. These results demonstrate that hyperpolarizing second-order neurons are important for the primate photopic ERG.(ABSTRACT TRUNCATED AT 400 WORDS)
Aminobutyrates↗
Expression of the SART3 tumor-rejection antigen in brain tumors and induction of cytotoxic T lymphocytes by its peptides.
The authors recently reported on the SART3 tumor-rejection antigen, which possesses epitopes that can induce cytotoxic T lymphocytes (CTLs) in patients with epithelial cancer. To explore a new modality for treatment of patients with brain tumors, this study investigated the expression of the SART3 antigen in patients with brain tumors and the ability of SART3 peptides to induce CTLs from peripheral blood mononuclear cells (PBMCs) of these patients. The SART3 antigen was detected in the cytoplasmic fraction of all 18 glioma cell lines examined and in the majority (31 of 34; 91%) of brain tumor tissues irrespective of their histologies. It was also expressed in the nuclear fraction of all 18 glioma cell lines and in the majority (26 of 34; 76%) of brain tumor tissues. In contrast, the SART3 was not expressed in nontumorous brain tissues. Cytotoxic T lymphocytes were induced in patients with glioma by stimulation with two epitope peptides of SART3. These CTLs could eliminate glioma cells in a HLA-A24-restricted manner. Therefore, the SART3 peptides may be appropriate molecules for use in peptide-based specific immunotherapy of HLA-A24+ patients with brain tumors.
Antigens, Neoplasm↗
F1 alpha: a novel mucin antigen associated with gastric carcinogenesis.
In a previous study, we obtained a novel monoclonal antibody (F1 alpha-75) directed against a synthetic mucin antigen termed F1 alpha, and demonstrated that this antigen was expressed in a high percentage (80.2%; 89/111) of gastric carcinomas. In the present study, we compared the expression of F1 alpha with that of sialyl-Tn antigen, a mucin antigen similar to F1 alpha, in 54 human early gastric carcinomas, intestinal metaplasia and adenomatous polyps of the stomach to determine how differences in the expression of these antigens correlated with gastric carcinogenesis. The rate of expression of F1 alpha in early gastric carcinoma tissues, 81.5%, was higher than that of sialyl-Tn antigen, 57.4%. No correlation was found between the rate of expression and histological type, depth of cancerous invasion or lymph node metastasis. Sialyl-Tn antigen was extensively expressed in 77.5% of specimens of complete intestinal metaplasia and in 78.6% of those of incomplete intestinal metaplasia; however, the expression of F1 alpha in those specimens was rare and sporadic, with rates of only 25.0 and 27.7%, respectively. In adenomatous polyps, the rate of expression of F1 alpha is 6.25% and that of sialyl-Tn antigen is 43.8%. Our findings indicate that F1 alpha is a more specific antigen for gastric cancer than sialyl-Tn antigen, and that F1 alpha is an antigen associated with carcinogenesis of the stomach.
Antigens, Tumor-Associated, Carbohydrate↗
Proceedings: 40. The analysis of the K-permeation in terms of affinity and the maximum number of channels.
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Cell Membrane Permeability↗