Search PubMed⌕ Search

Biomedical subjects

R Suzuki

Publications and source records attributed to R Suzuki.

At least 181 records · Page 10Linked to original sources
PubMed2000

Rapid determination of parvalbumin amino acid sequence from Rana catesbeiana (pI 4.78) by combination of ESI mass spectrometry, protein sequencing, and amino acid analysis.

The complete amino acid sequence of beta-type parvalbumin (PA) from bullfrog Rana catesbeiana (pI 4.78) was determined by tandem mass spectrometry in combination with amino acid analysis and peptide sequencing following Arg-C and V(8) protease digestion. The primary structure of the protein was compared with that of beta-type PA from R. esculenta (pI 4.50), with which it is highly homologous. Compared with R. esculenta beta-type PA4.50, R. catesbeiana beta-type parvalbumin (PA 4.78) differed in 15 out of 108 amino acid residues (14% displacement), PA4.78 had Cys at residue 64 and was acetylated at the amino terminus, but 25 residues of the carboxyl terminus were completely conserved. Several amino acid displacements were found between residues 51 and 80 (30% displacement), although the functionally important sequence of PA was completely conserved. The amino acids residues of putative calcium-binding sites were Asp-51, Asp-53, Ser-55, Phe-57, Glu-59, Glu-62, Asp-90, Asp-92, Asp-94, Lys-96, and Glu-101, which were conserved in all a and b-types of R. catesbeiana as well as other parvalbumins. In addition, Arg-75 and Glu-81, which are thought to form a salt bridge located in the interior of the molecule [Coffee, C.J. et al. (1976) Biochim. Biophys. Acta 453, 67-80], were also conserved in PA4.78.

Amino Acid Sequence↗
PubMed2000

Inhibition of inflammatory species by titanium surfaces.

Titanium has been used successfully for decades in orthopaedic and dental implants, but the mechanism mediating its biocompatible properties has not been elucidated. The authors investigated the possible role of titanium in modulating reactive oxygen mediators typically produced during the inflammatory response. Peroxynitrite is a highly reactive and unstable inflammatory mediator produced in vivo. This study found a 200% increase in the rate of degradation of peroxynitrite in the presence of titanium. To measure peroxynitrite reactivity, the nitration of 4-hydroxyphenylacetic acid by the peroxynitrite donor 3-morpholinosydnonimine was used. At a pH of 7.4, passivated titanium surfaces led to a 58% decrease of nitration of 4-hydroxyphenylacetic acid by peroxynitrite compared with controls in the absence of proteins. Surface treatments were found to influence the ability of titanium to inhibit peroxynitrite reactivity. Unpassivated titanium surfaces resulted in only a 10% decrease of nitrated 4-hydroxyphenylacetic acid, whereas titanium treated with hydrogen peroxide resulted in a 70% decrease. Decreases in nitration of 4-hydroxyphenylacetic acid also were seen with titanium in the presence of fibrinogen, 10% fetal calf serum, and sodium bicarbonate buffer. These results suggest that titanium is capable of enhancing the breakdown of the inflammatory mediator peroxynitrite and may account for the biocompatible properties of the material.

Biocompatible Materials↗
PubMed2000

Erythromycin resistance genes in Streptococcus pyogenes isolates in Kanagawa, Japan.

The susceptibility of 224 Streptococcus pyogenes isolates obtained from children in Japan from 1981 to 1997 to treatment with erythromycin was determined by the agar dilution method. A total of 17 isolates belonging to serotype M12T12 were resistant (MICs>1 microg/ml). Fourteen of the 17 resistant strains obtained from 1982 to 1985 harbored ermB and showed an identical pulsed-field gel electrophoresis pattern, indicating the spread of a single clone. Two ermTR-containing isolates were obtained in 1983. mefA gene was found in a strain obtained in 1994 in the present study, although this gene is predominantly associated with recent erythromycin resistance among S. pyogenes strains in many countries.

Anti-Bacterial Agents↗
PubMed2000

[Isolation of Aeromonas species from patients with sporadic diarrhea and characterization of Aeromonas hydrophila isolates].

A total of 16 strains of Aeromonas species were isolated from feces of 348 patients with sporadic diarrhea in western Kanagawa, Japan from 1996 to 1998. Of the 16 isolates, 7 were Aeromonas hydrophila, 1 was A. sobria and 8 were A. caviae. The strains of A. hydrophila were examined for hemolytic activities, hemolysin gene types and O-serogroups. Although all 7 strains of A. hydrophila showed hemolytic activities on sheep blood agar, in the test for hemolytic activities in culture supernatant, only 1 of the these strains showed no hemolytic activity against sheep erythrocytes. From the results of PCR assay, the tested strains of A. hydrophila were grouped into 2 hemolysin gene types of [ahh1 + ahh3 + aerA] (n = 6) and [ahh1 + aerA] (n = 1) both of which are recognized to be enteropathogenic. Five of the 7 strains of A. hydrophila belonged to serogroup O11. These results suggest that 7 strains of A. hydrophila isolates are recognized to be enteropathogenic strains and serogroup O11 is the major O-serogroup of enteropathogenic A. hydrophila in humans.

Aeromonas↗
PubMed2000

Hypertonic saline aerosol increases airway reactivity in the canine lung periphery.

Hyperventilation with dry air increases airway surface fluid (ASF) osmolality and causes acute mucosal injury, leukocyte infiltration, and delayed airway obstruction and hyperreactivity in canine peripheral airways. The purpose of this study was to determine whether ASF hypertonicity per se can account for these hyperventilation-associated effects. We first measured ASF osmolality before and after normal (NSC) and hypertonic (HSC) saline aerosol challenges to document the magnitude of hypertonicity produced by these stimuli. We then measured canine peripheral airway resistance and reactivity to hypocapnia and aerosolized histamine before and after NSC and HSC. Cells and eicosanoid mediators recovered in bronchoalveolar lavage fluid at 5 and 24 h after NSC and HSC were examined. We found that HSC but not NSC caused acute ASF hyperosmolality, increased mediator release, and delayed airway hyperreactivity in the absence of mucosal injury and leukocyte infiltration. These observations suggest that ASF hyperosmolality contributes to the development of the late-phase response to hyperventilation and further suggest that hyperventilation-induced mucosal injury independently initiates leukocyte infiltration and late-phase airway obstruction.

Aerosols↗
PubMed2000

Heparin inhibits eicosanoid metabolism and hyperventilation-induced bronchoconstriction in dogs.

Inhalation of heparin, an anticoagulant, attenuates exercise- induced asthma (EIA) in human subjects. The purpose of this study was to determine if heparin inhibits hyperventilation-induced bronchoconstriction (HIB) in a canine model of EIA, and if its mode of action involves the inhibition of eicosanoid mediator production and release. We used a wedged bronchoscope technique to measure baseline peripheral airway resistance (Rp). We then performed either a 2-min or 5-min dry air challenge (DAC) by temporarily increasing from 200 to 2,000 ml/min the flow of 5% CO(2) in air used to ventilate a wedged sublobar segment. We compared HIB before and 60 min after aerosol treatment with either bacteriostatic water (BW) or heparin. We found that (1) heparin had no effect on baseline Rp, (2) BW did not alter the response to DAC, and (3) heparin reduced HIB by approximately 50-60%. On the basis of bronchoalveolar lavage fluid (BALF) cell analysis, heparin and BW caused acute infiltration of macrophages and eosinophils, and heparin increased the number of erythrocytes recovered immediately after DAC. Despite these acute inflammatory effects initiated prior to DAC, BALF mediator analyses revealed that pretreatment with heparin either attenuated or abolished hyperventilation-induced leukotriene, prostaglandin, and thromboxane release. Thus, our data provide direct evidence that inhaled heparin inhibits eicosanoid mediator production and release caused by hyperventilation with dry air, and significantly attenuates HIB.

Administration, Inhalation↗
PubMed2000

High throughput screening for human interferon-gamma production inhibitor using homogenous time-resolved fluorescence.

An immunoassay for interferon-gamma (IFN-gamma) using homogeneous time-resolved fluorescence (HTRF) has been developed. In this assay, IFN-gamma can be detected by simply adding a mixture of three reagents-biotinylated polyclonal antibody, europium cryptate (fluorescence donor, EuK)-labeled monoclonal antibody, and crosslinked allophycocyanin (fluorescence acceptor, XL665) conjugated with streptavidin-and then measuring the time-resolved fluorescence. The detection limit of IFN-gamma by the proposed method is about 625 pg/ml. We applied the method to the detection of IFN-gamma secreted from NK3.3 cells and employed it in high throughput screening for IFN-gamma production inhibitors. With this screening format, IFN-gamma can be measured by directly adding the above reagents to microplate wells where NK3.3 cells are being cultured and stimulated with interleukin-12. This "in situ" immunoassay requires only pipetting reagents, with no need to transfer the culture supernatant to another microplate or wash the plate. Therefore, this screening format makes possible full automation of cell-based immunoassay, thus reducing cost and experimental time while increasing accuracy and throughput.

Antibodies, Monoclonal↗
PubMed2000

Growth inhibition of human leukemia HL-60 cells by an antisense phosphodiester oligonucleotide encapsulated into fusogenic liposomes.

We report here the antisense effect of phosphodiester oligodeoxynucleotide (D-ODN) using fusogenic liposomes (FL) as its carrier. FL has envelope proteins of the Sendai virus within its membrane and introduces its contents directly and efficiently into cytosol by means of the virus-cell fusion mechanism. Using antisense (AS) D-ODN 15-mer complementary to the c-myc proto-oncogene mRNA, including the translation initiation codon site, we analyzed the growth of HL-60 cells by [3H]-thymidine uptake. AS-ODNs encapsulated in FL inhibited the growth by about 70% that of the control HL-60 cells at 2.48 microM. In contrast, sense and scramble D-ODNs encapsulated in FL showed no effect of the growth of HL-60 cells at the same concentration. Even at 50 microM, free form D-ODNs did not show any effect. These results suggest that FL is potentially a useful delivery vehicle for oligonucleotide-based therapeutics, and that D-ODN may be a likely candidate for oligodeoxynucleotides when an efficient delivery system is used.

Base Sequence↗
PubMed2000

Super-high-definition image systems for telemedicine.

Super-high-definition (SHD) images are those with more than 2048 pixels x 2048 lines. They are of interest in the medical field because of their very high quality. We have developed a new SHD system for still pictures which is based on an SHD card that can be installed in a PC. We think that certain telemedicine applications will be facilitated by the use of SHD images.

Diagnostic Imaging↗
PubMed2000

Localization of mRNAs for novel, atypical as well as conventional protein kinase C (PKC) isoforms in the brain of developing and mature rats.

Using in situ hybridization histochemistry, the localization of mRNAs for 10 isoforms of protein kinase C (PKC) in the rat brain was studied at embryonic and postnatal stages. In the embryonic brain, the gene expression was positive only for PKCepsilon, mu, lambda, and zeta with the former three more evident: The expression for PKCmu and lambda in the ventricular germinal zone and that for PKCepsilon, zeta, and lambda in the mantle zone. In the postnatal brain, the expression for PKCdelta, eta, and theta was detected differentially in a few circumscribed loci such as the thalamus, the habenula, the septum, and the cerebellar granule cells, whereas that for the other isoforms was seen widely in various loci of the gray matter with different intensity. The expression in the cerebellar external granule cell layer was positive only for PKCbeta (betaI and betaII), mu, and lambda with that for PKCbeta confined to its inner zone. There is a general tendency for all PKC isoforms that the expression levels reach at peaks in early postnatal brain and decreases more or less in adult specimens. This is the first report on the spatio-temporal heterogeneity in the gene expression for the whole members of PKC family in the brain throughout development, especially at embryonic days.

Aging↗
PubMed2000

Ocular larva migrans caused by Toxocara cati in Mongolian gerbils and a comparison of ophthalmologic findings with those produced by T. canis.

To elucidate the pathogenic potential of Toxocara cari, we observed the ophthalmologic changes of the fundi in Mongolian gerbils, Meriones unguiculatus, after oral inoculation of 17 embryonated eggs/g body weight. Ophthalmic conditions in 8 T. cati-infected gerbils were monitored using an ophthalmoscope from day 0 to day 156 and were compared with those of 57 T. canis-infected gerbils. The results showed that T. cati larvae migrated into the eye of the gerbil and then elicited ophthalmic changes, including retinal (25%) and vitreous (50%) hemorrhaging, vasculitis (37.5%), and exudative lesions (25%). Lesions were less prevalent, however, in T. cati-infected than in T. canis-infected gerbils. Unlike in T. canis-infected gerbils, the hemorrhagic lesions did not reappear in T. cati-infected gerbils after they were absorbed. These findings suggested that T. cati larvae are a potentially hazardous pathogen for ocular toxocariasis and that Mongolian gerbils infected with T. cati may be a useful model for the study of human ocular toxocariasis caused by T. cati. This is the first study to report that T. cati larvae can induce ophthalmic lesions in the retina of gerbils.

Animals↗
PubMed2000

Correlation of magnetic resonance imaging and histological findings in a large basilar tip aneurysm after coil embolization--case report.

A 73-year-old female with a large basilar tip aneurysm underwent endovascular coil embolization with interlocking detachable coils (IDCs). The patient subsequently died of pneumonia 25 days after the embolization, and the aneurysm specimen was obtained at autopsy. Histological examination showed that the intraaneurysmal structure consisted of three layers. The outer layer was mildly organized thrombus surrounding the coils, the middle layer was disorganized clot, and the inner layer consisted of fresh blood clot. Gradient-echo magnetic resonance (MR) imaging taken before death had demonstrated a central region of high intensity and a peripheral low intensity region corresponding to the inner and middle-outer layers of the aneurysm, respectively. Intraaneurysmal placement of IDCs leads to the formation of a clot surrounding the coils. However, clot formation may be inadequate where the packing of the IDCs is incomplete. Comparison of the MR imaging and histological findings in this case show that gradient-echo MR imaging can assess thrombus and residual blood flow within the aneurysm.

Aged↗
PubMed2000

Disruption of insulin receptor substrate 2 causes type 2 diabetes because of liver insulin resistance and lack of compensatory beta-cell hyperplasia.

To investigate the role of insulin receptor substrate (IRS)-2 in vivo, we generated IRS-2-deficient mice by gene targeting. Although homozygous IRS-2-deficient mice (IRS-2-/- mice) had a body weight similar to wild-type mice, they progressively developed type 2 diabetes at 10 weeks. IRS-2-/- mice showed insulin resistance and a defect in the insulin-stimulated signaling pathway in liver but not in skeletal muscle. Despite insulin resistance, the amount of beta-cells was reduced to 83% of that in wild-type mice, which was in marked contrast to the 85% increase in the amount of beta-cells in IRS-1-deficient mice (IRS-1-/- mice) to compensate for insulin resistance. Thus, IRS-2 plays a crucial role in the regulation of beta-cell mass. On the other hand, insulin secretion by the same number of cells in response to glucose measured ex vivo was significantly increased in IRS-2-/- mice compared with wild-type mice but was decreased in IRS-1-/- mice. These results suggest that IRS-1 and IRS-2 may play different roles in the regulation of beta-cell mass and the function of individual beta-cells.

Animals↗
PubMed2000

[Anesthetic management in a patient with severe acute pancreatitis during pregnancy].

Continuous epidural anesthesia was used in a 34 year-old pregnant woman with acute pancreatitis related to hypertriglyceridemia. She underwent an emergency cesarean section due to severe pancreatitis under spinal anesthesia. After delivery, extended incision was made to examine the pancreas and to perform drainage. Epidural infusion using 1% mepivacaine and buprenorphine was started to reduce pain and improve microcirculation. After starting epidural infusion with other therapies, clinical feature and data improved. This case suggests that reduction of severe pain and improvement of microcirculation are important in therapies of severe pancreatitis.

Acute Disease↗