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Biomedical subjects

Y Mine

Publications and source records attributed to Y Mine.

At least 19 recordsLinked to original sources
PubMed2001

Cloning and expression of human rotavirus spike protein, VP8*, in Escherichia coli.

A system for the expression and purification of soluble VP8*, part of the human rotavirus (HRV) spike protein, was established by expressing VP8* as a fusion protein with glutathione S-transferase (GST). VP8 cDNA, from the Wa strain of HRV, was prepared by RT-PCR, cloned into a pUC18 plasmid, and inserted into a pGEX-4T-2 GST fusion vector. The GST-VP8* fusion protein was expressed in Escherichia coli, and the VP8* was purified by Glutathione Sepharose 4B affinity chromatography, yielding 1.8 mg VP8*/L culture. The purified VP8* was used to vaccinate chickens, eliciting antibodies which displayed high neutralization activity against the Wa strain of HRV, suggesting its use for the induction of specific neutralizing antibodies for potential immunotherapeutic applications for the prevention of HRV infection.

Amino Acid Sequence↗
PubMed2001

A new macrocyclic trichothecene, 12,13-deoxyroridin E, produced by the marine-derived fungus Myrothecium roridum collected in Palau.

A new macrocyclic trichothecene, 12,13-deoxyroridin E (1), and three known compounds, roridin E (2), verrucarin A (3), and verrucarin J (4), were obtained as cytotoxic components from the marine-derived fungus Myrothecium roridum, isolated in Palau. 12,13-Deoxyroridin E is the second example of a macrocyclic trichothecene possessing a double bond at C-12-C-13 and was about 80-fold less cytotoxic than roridin E, the epoxide variant.

Animals↗
PubMed2000

Immunochemical and structural analysis of pepsin-digested egg white ovomucoid.

Ovomucoid, an egg protein comprising approximately 10% egg white, was digested using the enzyme pepsin, and fragments were isolated by anion-exchange and reverse phase HPLC. Four distinct fragments were identified by analysis with SDS-PAGE, including three large fragments with molecular weights of around 24, 18, and 14 kDa. N- and C-terminal and amino acid sequencing analyses identified the fragments as V134-C186 (domain 3), V21-A133, and A1-A133 (domain 1+2). Further separation and sequencing of the fraction composed of small peptides, to determine their exact makeup and location in the protein, remained to be carried out and identified a peptide G51-Y73. All four fragments showed IgE-binding activity, as measured by ELISA, using human sera from egg-allergic individuals. Little change in the digestibility of ovomucoid by trypsin and chymotrypsin was observed following digestion with pepsin, indicating that pepsin-digested ovomucoid retains its trypsin (protease) inhibitor activities. Reduced carboxymethylated ovomucoid was prepared, and digestion with pepsin produced significantly more peptides than did the digestion of the native ovomucoid, indicating that the disulfide bonds play a significant role in the digestive resistance of ovomucoid. The reduction of ovomucoid enhanced its digestibility and lower allergenicity of the protein.

Digestion↗
PubMed2000

Preparation of novel functional oligophosphopeptides from hen egg yolk phosvitin.

Novel hen egg phosvitin phosphopeptides (PPP) with molecular masses of 1-3 kDa were prepared from tryptic hydrolysis following partial alkaline dephosphorylation. The phosvitin treated with various NaOH concentrations (0.05-0.4 N) resulted in different dephosphorylated proteins ranging from 17.5 to 96.3% of phosphate retention. The protein was digested into 10-20 amino acid peptides with trypsin. Calcium-binding properties of PPP were compared with those of commercial casein phosphopeptides in vitro. The PPP with 35% phosphate retention is shown to be effective for enhancing calcium binding capacity and inhibiting the formation of insoluble calcium phosphate. The results provide potential novel functional oilgophosphopeptides as nutraceuticals.

Amino Acids↗
PubMed2000

Effects of hen egg yolk immunoglobulin in passive protection of rainbow trout against Yersinia ruckeri.

Anti-Yersinia ruckeri egg yolk immunoglobulin (IgY) was transferred to egg yolk after immunization of White Leghorn hens with formalin-killed whole cells of serovar 1 (RS1154) and serovar 2 (RS1153)Y. ruckeri and its lipopolysaccharide (LPS). The IgY was specific for its homologous LPS in western immunoblot, whereas some protein bands were commonly recognized, even by IgY from eggs of unimmunized hens. Purified LPS from both Y. ruckeri serovar types 1 and 2 had a very poor immunogenicity. The IgY activity was stable when processed into pellet form by a microbial transglutaminase treatment and showed a considerable resistance against acid pepsin for at least 2 h. Feeding specific anti-serovar 1 Y. ruckeri IgY to fish either before or after immersion infection produced marginal reductions in mortalities and in intestine infection. The same IgY did passively protect rainbow trout against infection when administered by intraperitoneal injection 4 h before an immersion challenge.

Animals↗
PubMed2000

Liver lesions: intermittent second-harmonic gray-scale US can increase conspicuity with microbubble contrast material-early experience.

The authors investigated the effect of intermittent second-harmonic gray-scale (ISHGS) ultrasonography (US) with SH U 508A microbubbles on the conspicuity of focal liver lesions. Twenty-three patients were included in the study. Images were analyzed subjectively and quantitatively. Objective lesion conspicuity was increased. In 12 of the 15 patients with liver malignancy, gray-scale defects were seen in previously unsuspected areas. ISHGS US may improve the sensitivity of US for liver lesions.

Adult↗
PubMed2000

Electrophoretic and immunochemical characterization of allergenic proteins in buckwheat.

BACKGROUND: Buckwheat allergies are not common, however, it is considered to be a very potent allergen. Ingestion of small amounts has been found to produce anaphylactic reactions, particularly in children. Identification and characterization of the major allergen(s) in buckwheat are currently underway, however, there are some discrepancies in the findings. METHODS: Identification of the major allergen(s) was determined through Western blotting using buckwheat-allergic patients' sera. Once the allergenic proteins were identified, they were purified, their IgE-binding activity assessed through an indirect ELISA and the N-terminal amino acid sequence completed. To assess the stability of the IgE-binding epitopes, protein fractions were exposed to various treatments and assayed using an indirect ELISA. Lastly, the presence of anti-buckwheat IgG in the patients' sera was analyzed through Western blotting and ELISA. RESULTS: IgE binding was detected to proteins with molecular masses of approximately 14 and 18 kDa. N-terminal sequencing was completed and found to share some homology with rice proteins associated with rice allergies and cross-allergenicity with buckwheat proteins. When the water-soluble protein fraction was heated, exposed to acidic and alkaline conditions and fully denatured, IgE-binding activity was reduced. When the fraction was partially denatured through urea, IgE-binding activity increased. Furthermore, IgG-binding activity was detected with proteins only above the 20 kDa region. CONCLUSIONS: Proteins with molecular masses around 14 and 18 kDa were identified as the major allergenic proteins in the buckwheat-allergic patients' sera tested in this study. Results also indicate that these two proteins possess IgE-binding capability.

Adolescent↗
PubMed1999

Characterization of residues in human IgE and IgG binding site by chemical modification of ovomucoid third domain.

Chemical modification of ovomucoid third domain (DIII) has been conducted to characterize the binding site residues that determine antigenecity and allergenecity of DIII. Nitration of Tyr, ethoxyformylation of His and succinylation of Lys residues led to a decrease of alpha-helix content of DIII. Modification of His, Tyr, Glu, Asp and Lys residues on DIII resulted in a reduction of human IgG binding activity, but little effect on IgE binding activity. These results suggest that hydrophilic residues appear to be more critical for human IgG binding site, whereas hydrophobic residues may be more important for IgG binding site.

Acylation↗
PubMed1999

Analysis of flash echo from contrast agent for designing optimal ultrasound diagnostic systems.

Microbubble-based contrast agents can enhance echoes in areas of low blood flow, but the bubbles are extremely sensitive and collapse easily when exposed to ultrasound (US) irradiation. An experimental study of bubble collapse was carried out to design new functions for US diagnostic systems to detect echoes from microbubbles more efficiently. For contrast agent (Levovist) solution, a high-intensity, but momentary, echo (flash echo), was observed in the first frame image after a several-second suspension of transmission, but was not seen in the second frame image. These "flash echo" signals were analyzed and categorized based on microscopic observation, and the results showed that the longevity of the microbubbles was reduced by conditions such as B-mode imaging. Next, a numerical simulation of the bubbles in liquid was performed under the same conditions as in the in vitro experiment. The results showed that even bubbles less than 1 microm in diameter expand and collapse within one pulse drive, which would generate flash echoes. The flash echo imaging system described here permits flexible intermittent scanning with variable intervals, with a variable number of frames at the trigger, and with simultaneous monitoring at low power output. Animal experiments were also conducted to evaluate the system. As the interval between frames was increased, the flash echoes gradually increased, and perfusion in the parenchyma was clearly observed with an interval of 4 s.

Animals↗
PubMed1999

In vivo kinetics of microbubbles of SH U 508 A (Levovist): comparison with indocyanine green in rabbits.

The aim of this study was to evaluate in vivo kinetics of microbubbles of SH U 508 A, in comparison with Indocyanine Green, a dye used as an indicator of blood flow. Microbubble kinetics were evaluated in various vessels (i.e., vena cava, aorta, renal artery, renal vein and portal vein) in rabbits after injection of SH U 508 A by measuring Doppler signals (n = 5). The kinetics of Indocyanine Green were evaluated by measuring absorbance using a photodiode (n = 5). Test substances (SH U 508 A 300 mg/mL and Indocyanine Green 1.25 mg/mL) were injected IV at a dose of 0.1 mL/kg B.W. Peak signal intensity was observed immediately after injection of SH U 508 A, followed by biphasic decay. The rates of biphasic decay were similar in all vessels. A second peak of the signal, which indicated recirculation of the microbubbles, was observed in the vena cava. The circulation and recirculation times of the microbubbles after injection of SH U 508 A were similar to that of Indocyanine Green. These findings suggest that the majority of SH U 508 A microbubbles circulate through the body similarly to blood flow, without retention, in the vasculature.

Animals↗
PubMed1998

Characterization of IgE and IgG epitopes on ovomucoid using egg-white-allergic patients' sera.

To investigate the importance of linear and conformational structure and carbohydrate chains in hen ovomucoid epitopes, the IgG and IgE binding activities of three native and reduced carboxymethylated (RCM) domains (DI, DII, and DIII) were compared using human sera from egg-white-allergic patients. There was significantly more IgG and IgE binding activity to DIII than to DI and DII. The IgG binding activity to RCM domains was similar to the native form, while RCM-DIII had significantly greater binding activity to IgE antibody (p < 0.05). It indicated that the main IgE and IgG epitopes on each domain were of linear structure. However, the total reactivity of the three domains was estimated to be about 50-60% (IgG binding) and 55-75% (IgE binding) compared with total reactivity in ovomucoid, resulting in some ovomucoid epitopes consisting of conformational epitopes on domain I-II or II-III. The carbohydrate moieties in DIII had a rather inhibiting effect on its IgG and IgE binding activities.

Allergens↗
PubMed1998

Detection of DNA lesions induced by chemical mutagens by the single cell electrophoresis (Comet) assay. 1. Relationship between the onset of DNA damage and the characteristics of mutagens.

We evaluated the relationship between the onset of DNA damage and the characteristics of 5 model chemical mutagens with the single-cell gel electrophoresis (SCG) assay using L5178Y mouse lymphoma cells. We treated the cells with each chemical for 3 h and sampled them 0.21, and 45 h after treatment. DNA damage induced by UV mimetic mutagens MMS and MNU, and X-ray mimetic mutagen BLM was observed just after treatment, crosslinking agent MMC-induced DNA damage was detected 21 h after treatment, and 6-MP as an inhibitor of DNA synthesis did not induce DNA damage at any sampling time. These results suggest that the SCG assay detects DNA lesions just after treatment with UV and X-ray mimetic mutagens, but needs a waiting period after treatment with crosslinking agents.

Animals↗
PubMed1998

Adsorption Behavior of Egg Yolk Low-Density Lipoproteins in Oil-in-Water Emulsions.

Adsorption behavior of egg yolk low-density lipoprotein (LDL) constituents in oil-in-water emulsions (20% triolein) was examined. The mean particle size was decreased with increase in LDL concentrations and reached a plateau at 60 mg/mL of LDL concentrations. The average particle size and concentration of lipoproteins at the interface were greater for emulsions made at pH 3.0 and 5.0 than at pH 7.0 and 9.0, resulting from the formation of lipoprotein dimers at acid pHs. Electrophoretic analysis revealed that the three polypeptides (64, 43, and 19 kDa) in LDL constituents did not adsorb at the interface, independent of the LDL concentration, pHs, and NaCl content. On the other hand, cholesterol in LDL was preferentially adsorbed to the interfaces at the low LDL concentration. The ratio of phosphatidylcholine and phosphatidylethanolamine was increased with increased of LDL concentration. These results suggest that egg yolk LDL micelles breakdown when the micelles come into contact with the interface and rearrangement of lipoproteins, cholesterol, and phospholipids take place following adsorption at an O/W interface.

Journal Article↗
PubMed1998

Affinity of mosapride citrate, a new gastroprokinetic agent, for 5-HT4 receptors in guinea pig ileum.

We examined the binding affinity of mosapride citrate (mosapride) (4-amino-5-chloro-2-ethoxy-N-[[4-(4-fluorobenzyl)-2-morpholinyl]me thyl] benzamide citrate), a novel gastroprokinetic agent, for the 5-hydroxytryptamine (5-HT) 4 receptors in guinea pig ileum using a selective 5-HT4-receptor radioligand, [3H]GR113808. In membrane preparations from longitudinal muscle with myenteric plexus in guinea pig ileum, specific [3H]GR113808 binding revealed a single saturable site of high affinity (Kd=0.28 +/-0.02 nM, Bmax = 45+/- 3 fmol/mg protein). Mosapride and other 5-HT4-receptor agonists inhibited the specific binding of [3H]GR113808 in guinea pig ileum. The 5-HT4 agonists examined displayed the following inhibition potency order: BIMU-8 > cisapride > mosapride > renzapride > 5-HT > zacopride > metoclopramide. Mosapride exhibited monophasic inhibition of the specific [3H]GR113808 binding in the ileum (Ki value: 84.2 nM). The presence of mosapride (30 nM) significantly increased the Kd value to 0.44+/-0.05 nM in the Scatchard analysis of [3H]GR113808 binding. Bmax of [3H]GR113808, however, was not affected (48 +/-4 fmol/mg protein) by mosapride. As for the affinity of mosapride, the addition of GppNHp (100microM) slightly increased the Ki value to 104 nM. These results indicate that mosapride has an affinity for 5-HT4 receptors in guinea pig ileum in the radioligand binding study.

Animals↗
PubMed1998

Complete amino acid sequence of chitinase-a from bulbs of gladiolus (Gladiolus gandavensis).

The complete amino acid sequence of gladiolus bulb chitinase-a (GBC-a) was determined. First the tryptic peptides from GBC-a after it was reduced and S-carboxymethylated were sequenced and then the peptides were further studied by chemical cleavage of the enzyme. GBC-a consisted of 274 amino acid residues and had a molecular mass of 30,714 Da. Two consensus sequences essential for chitinase activity by plant class III chitinases were conserved in GBC-a, although its sequence similarity with plant class III chitinases was less than 20%. Sequence comparison of GBC-a with sequences of other proteins in a protein identification resource (PIR) showed that the GBC-a sequence was 33% similar to that of narbonin, a seed storage 2S globulin from narbon beans.

Amino Acid Sequence↗
PubMed1998

[Harmonic imaging].

Microbubbles undergoing resonant oscillation in a diagnostic ultrasound field can be induced to exhibit nonlinear motion. The ultrasound signals emitted by such microbubbles contain strong harmonics at twice the frequency of the transmitted ultrasound beam. Second harmonic imaging improves tissue-agent contrast. The usefulness of second harmonic imaging was evaluated in vivo experiments. The hepatic parenchyma was clearly enhanced in dogs. Second harmonic imaging can be expected to expand the capabilities of diagnostic ultrasound systems in visualizing tissue perfusion.

Animals↗
PubMed1997

Detection of DNA lesions induced by chemical mutagens by the single cell gel electrophoresis (Comet) assay. 1. Relationship between the onset of DNA damage and the characteristics of mutagens.

We evaluated the relationship between the onset of DNA damage and the characteristics of 5 model chemical mutagens with the single-cell gel electrophoresis (SCG) assay using L5178Y mouse lymphoma cells. We treated the cells with each chemical for 3 h and sampled them 0, 21, and 45 h after treatment. DNA damage induced by UV mimetic mutagens MMS and MNU, and X-ray mimetic mutagen BLM was observed just after treatment, crosslinking agent MMC-induced DNA damage was detected 21 h after treatment, and 6-MP as an inhibitor of DNA synthesis did not induce DNA damage at any sampling time. These results suggest that the SCG assay detects DNA lesions just after treatment with UV and X-ray mimetic mutagens, but needs a waiting period after treatment with crosslinking agents.

Animals↗