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Biomedical subjects

T Iida

Publications and source records attributed to T Iida.

At least 217 records · Page 12Linked to original sources
PubMed1996

Gene for aspartate racemase from the sulfur-dependent hyperthermophilic archaeum, Desulfurococcus strain SY.

Amino acid racemases are ubiquitous throughout eubacteria. However, no amino acid racemases have yet been found in eukaryotes and archaea. We cloned a gene highly homologous to that for the aspartate racemase from the sulfur-dependent hyperthermophilic archaeum, Desulfurococcus strain SY. The product of the gene showed 35.2% amino acid sequence identity with the aspartate racemase of Streptococcus thermophilus IAM10064, and was also homologous to glutamate racemases around the putative catalytic cysteine residues. The encoded protein was expressed in Escherichia coli. The recombinant protein had amino acid racemizing activity, which was highly specific for aspartate and increased with temperature from 37 degrees C to 90 degrees C. Therefore, this was identified as the first hyperthermophilic archaeal amino acid racemase. A little aspartate racemizing activity was also detected in the crude extract of Desulfurococcus strain SY. The function of this aspartate racemase might be the uptake of -aspartate formed at high temperature or the production of -aspartate as a cell component. The fact that the amino acid racemases are distributed among both eubacteria and archaea suggests that endogenous -amino acids in mammals are also synthesized by amino acid racemases.

Amino Acid Isomerases↗
PubMed1996

Proton: a major factor for the racemization and the dehydration at the cyclization/cleavage stage in the Edman sequencing method.

The racemization of the liberated 7-[(N,N-dimethylamino)sulfonyl]-4-(2,1,3-benzoxadiazolyl)-thiazoli none (DBD-TZ) amino acid during the cyclization/cleavage reaction with trifluoroacetic acid (TFA) in the Edman sequencing procedure has been carefully investigated, and evidence is presented to show conclusively that the racemization is caused by the replacement of a hydrogen atom by TFA. The fluorescent reagent 7-[N,N-dimethylamino)sulfonyl]-4-(2,1,3-benzoxadiazolyl) isothiocyanate (DBD-NCS) was used for amino acid sequencing, and DBD-TZ amino acid was used for sequence and configuration determination. DBD-thiocarbamoylated peptides were cyclized and cleaved with deuterated TFA, and the protonated pseudomolecular ions (M-d1 + H)+ of DBD-TZ amino acids were detected by LC/MS. Furthermore, in the reaction kinetics study, we confirmed that the replacement reaction by TFA correlated sufficiently with the racemization of DBD-TZ amino acids. For the purpose of retaining D/L-amino acid configuration in sequencing, we used an aprotic acid, i.e., the Lewis acid boron trifluoride (BF3), for the cyclization/cleavage reaction. When we used BF3, the derivatized DBD-TZ amino acid was scarcely racemized under cyclization/cleavage conditions. Using this method, amino acid sequencing of D-Phe-Met-Arg-Phe-amide could be performed, retaining the D/L-configuration of the amino acid residues.

Amino Acid Sequence↗
PubMed1996

Chemical structure of lipid A isolated from Comamonas testosteroni lipopolysaccharide.

The chemical structure of lipid A of lipopolysaccharide isolated from Comamonas testosteroni was determined by quantitative analysis, methylation analysis, mass spectrometry and NMR spectroscopy. The lipid A backbone was found to consist of 6-O-(2-deoxy-2-amino-beta-D-glucopyranosyl)-2-deoxy-2-amino-alpha-D-g luc ose which was phosphorylated in positions 1 and 4'. Hydroxyl groups at positions 4 and 6' were unsubstituted, and position 6' of the non-reducing terminal residue was identified as the attachment site of the polysaccharide part. Liquid secondary-ion/mass spectrometry revealed a pseudomolecular ion at m/z 1572 [M-H]- as a major diphosphoryl lipid component carrying six acyl groups. Fatty acid distribution analysis and electrospray ionization/mass spectrometry of the lipid A showed that positions 2,2',3, and 3' of the sugar backbone were N-acylated or O-acylated by (R)-3-hydroxydecanoic acid, and that the hydroxyl groups of the amide-linked residues attached to positions 2 and 2' were further O-acylated by tetradecanoic and dodecanoic acids, respectively.

Carbohydrate Sequence↗
PubMed1996

Influence of CO2 tension on hepatic hemodynamics during portal arterialization.

We investigated the effect of portal arterialization (PA) on hepatic energy metabolism and hepatic hemodynamics. Portal perfusion flow rate with arterial blood was 25% of the preperfusion portal flow. During PA up to 120 min, hepatic energy metabolism was maintained from the aspects of ATP, energy charge, and arterial ketone body ratio. However, during this PA, carbon dioxide tension (25-35 mm Hg) in arterial blood was lower than that in normal portal vein blood and portal vein resistance (PVR) was significantly increased during perfusion compared with that at preperfusion. When carbon dioxide tension (50-63 mm Hg) in arterial blood was made equivalent to that in normal portal vein blood by controlling the respiratory conditions, PVR was not increased during PA up to 120 min. It was suggested that PCO2 in perfusion blood should change PVR, while it should not change hepatic energy metabolism when portal perfusion flow rate with arterial blood was 25% of the preperfusion portal flow.

Animals↗
PubMed1996

Laparoscopic-assisted creation of a vagina.

The applicability of laparoscopy for colpopiesis using pelvic peritoneum was examined in two women with the Mayer-Rokitansky-Kuster-Hauser syndrome. Using a modification of laparoscopic guidance proved advantageous for safe dissection of the vesicorectal space and accurate suturing of the pelvic peritoneum without laparotomy. A sufficient vaginal cavity was achieved in both patients. This modification of the original procedure, featuring introduction of a laparoscope, thus provides effective and safe conditions for creation of a new vagina.

Adult↗
PubMed1996

Phosphorylation of a 25 kDa protein is induced by thermostable direct hemolysin of Vibrio parahaemolyticus.

Thermostable direct hemolysin (TDH) is a possible virulence factor produced by Vibrio parahaemolyticus. Although TDH has a variety of biological activities, including hemolytic activity, the biochemical mechanism of action remains uncertain. Here we analysed biochemical events, especially phosphorylation, caused by TDH in erythrocytes, and found that TDH caused significant phosphorylations of proteins on erythrocyte membrane. Phosphorylation of proteins was studies using [gamma-32P] ATP and SDS-PAGE. A number of protein kinase inhibitors were tested, to determine which types of kinases were involved in the phosphorylation events. TDH induced the phosphorylation of two proteins on membranes of human erythrocyte that are sensitive to TDH. The estimated molecular weight of these proteins was 25 and 22.5 kDa. Interestingly, the 22.5 kDa, but not the 25 kDa protein, was phosphorylated on the membrane of TDH-insensitive (resistant) horse erythrocytes. Moreover, a mutant TDH (R7), which retained binding ability but lost hemolytic activity, also phosphorylated only the 22.5 kDa protein on human erythrocyte membranes. Among the protein kinase inhibitors used the protein kinase C inhibitors, (staurosporine and calphostin C) showed marked inhibition of phosphorylation of 25kDa protein. In addition to phosphorylation, these protein kinase C inhibitors suppressed hemolysis by TDH. These results indicate that the phosphorylation of the 25 kDa protein seems to be essential for the hemolysis by TDH after it binds to erythrocyte membranes.

Bacterial Toxins↗
PubMed1996

Ketamine inhibits nitric oxide production in mouse-activated macrophage-like cells.

We have investigated the effects of ketamine on nitric oxide produced by activated macrophages using a murine macrophage-like cell line, J774. Cells were incubated for 18 h under stimulation with lipopolysaccharide and interferon-gamma or lipoteichoic acid and interferon-gamma, with various concentrations of ketamine (6-600 mumol litre-1). Nitric oxide production was assessed by measuring nitrite, a stable by-product of nitric oxide breakdown, in the medium. Other N-methyl-D-aspartate receptor antagonists, MK-801 (150 mumol litre-1) and dextromethorphan (150 mumol litre-1) were also tested. In addition, we studied the effects of ketamine on production of tumour necrosis factor-alpha by activated macrophages. Ketamine inhibited nitrite production dose-dependently with both lipopolysaccharide- and lipoteichoic acid-activated macrophages by up to approximately 65% at the highest ketamine concentration (600 mumol litre-1). Neither MK-801 nor dextromethorphan had an inhibitory effect. Ketamine also suppressed production of tumour necrosis factor-alpha. The data show that ketamine inhibited nitric oxide production by activated macrophages probably, in part, via inhibition of production of tumour necrosis factor-alpha, an autocrine stimulatory factor for nitric oxide production, but not via the NMDA receptor pathway, which is involved in neuronal nitric oxide production.

Anesthetics, Dissociative↗
PubMed1996

Identification of a Gly862 to Ser substitution in the type I collagen gene from a single spermatozoon.

Individual spermatozoa from the father of two affected infants with osteogenesis imperfecta were separated by dilution and micromanipulation. A segment of the type I collagen gene containing the mutant region was amplified by nested polymerase chain reaction and sequenced. Among 40 individual spermatozoa, 15 specimens were identified as mutants with a substitution of guanine3208 to adenine (glycine862 to serine) while 18 and seven specimens were of the wild and mixed types respectively. Through this study, we have established a molecular procedure that can be considered as prerequisite for preimplantation diagnosis of genetic disorders with a single point mutation.

Collagen↗
PubMed1996

Development of an atmospheric 222Rn concentration model using a hydrodynamic meteorological model: I. One-dimensional practical model.

A one-dimensional numerical model for 222Rn transport in an atmospheric boundary layer was developed. The model consists of two parts: a prognostic hydrodynamic model including a turbulence closure model and an atmospheric diffusion model for 222Rn. The first part predicts meteorological conditions to provide the second part with vertical turbulence conditions which affects the vertical motion of 222Rn near the Earth's surface. Calculations with the model are compared with 222Rn concentrations measured during a variety of meteorological conditions, from clear days with high radiation and low winds to cloudy days of low radiation with high winds. The model's results represent well the typical diurnal variations of the 222Rn concentrations.

Air Pollutants, Radioactive↗
PubMed1996

Pemphigus vulgaris exacerbated by exposure to sunlight.

We report two cases of pemphigus vulgaris who showed exacerbation of their bullous skin lesions after exposure to sunlight. These cases indicate that ultraviolet light is an aggravating factor, not only for pemphigus foliaceus, but also for pemphigus vulgaris.

Adult↗
PubMed1996

Pemphigoid and pemphigus foliaceus successfully treated with topical corticosteroids.

Six patients with pemphigoid and three patients with pemphigus foliaceus were successfully treated with topical corticosteroids. This was especially effective in cases of pretibial localized pemphigoid and in mild cases of bullous pemphigoid and pemphigus foliaceus with negative or low-titer circulating autoantibodies.

Administration, Topical↗
PubMed1996

The prevalence of Listeria monocytogenes in the environment of dairy farms.

The prevalence of Listeria monocytogenes in the environment of dairy farms was surveyed from December 1993 to June 1994 in one city of Hokkaido. L. monocytogenes was isolated from 3 out of 5 farms investigated. Serovar 4b organism was isolated from the brain stem of a cow from one farm which was clinically diagnosed as having listeriosis. The same serovar of L. monocytogenes was also isolated from the rectal contents of a healthy cow, straw on the floor, straw in the barn, and silage scattered around the silo from the same farm. At another farm, with no reported cases of bovine listeriosis, serovar 1/2 organism was isolated from the same types of samples as the above mentioned farm except from straw on the floor. The difference in the isolation rates of the organism from straw on the floor between the two farms (22%:5/23 vs 0%:0/24) is considered to be caused by the different feeding methods of silage between the two farms.

Animals↗
PubMed1996

Bullous pemphigoid associated with internal malignancies: identification of 180-kDa antigen by western immunoblotting.

We report three cases of bullous pemphigoid associated with internal malignancies. Two cases were associated with gastric cancer and one with rectal cancer. Immunoblot analysis, using epidermal extract of normal human skin, revealed that these patients' sera reacted only with bullous pemphigoid antigen with a molecular weight of 180 kDa (BP180). The relationship of BP180 to malignant tumours is discussed.

Adenocarcinoma↗
PubMed1996

Restriction fragment length polymorphism of the tdh and trh genes in clinical Vibrio parahaemolyticus strains.

The restriction fragment length polymorphism of the genes encoding thermostable direct hemolysin (tdh) and thermostable direct hemolysin-related hemolysin (trh) was analyzed for 137 strains of Vibrio parahaemolyticus isolated from specimens from diarrheal patients in Thailand. The HindIII restriction fragment patterns of tdh and trh were grouped into five and four types, respectively. A strong association between the restriction fragment patterns of tdh and trh was observed with V. parahaemolyticus strains.

Bacterial Proteins↗
PubMed1996

Analysis of the testis-determining gene SRY in patients with XY gonadal dysgenesis.

The sex-determining region of the Y chromosome (SRY) encodes a gene that has many of the properties expected to the testis-determining factor. XY gonadal dysgenesis is characterized by streak gonads in phenotypic females who lack the somatic abnormalities and short stature associated with Turner's syndrome. We have examined four patients with XY gonadal dysgenesis for the presence and absence of SRY and the DNA sequence of the gene. The results showing that one was negative for SRY and another had a mutation within the gene have confirmed the etiological role of SRY in XY gonadal dysgenesis. However, the other two patients with short stature had apparently normal SRY. DNA sequencing of the SRY gene showed 100% nucleotide sequence identity with the reported cloned sequence. Sex reversal in two of the present cases may be due to mutation at a locus other than SRY in the sex-determining pathway, a gene potentially involved in the determination of human sexual constitution.

Adolescent↗
PubMed1996

Fucoidin, a potent inhibitor of leukocyte rolling, prevents neutrophil influx into phorbol-ester-induced inflammatory sites in rabbit lungs.

The polysaccharide fucoidin, a homopolymer of sulfated L-fucose, is known, by interfering with the function of L-selectin, to inhibit leukocyte rolling, which is an early and essential step in the process of leukocyte extravasation into inflamed sites. We tested the inhibitory effect of fucoidin on neutrophil accumulation in lung inflammation induced by phorbol myristate acetate and peritoneal inflammation induced by thioglycollate in rabbits. Pretreatment (10 mg/kg) followed by continuous administration (10 mg/kg/h) of fucoidin dramatically reduced the number of neutrophils recruited into the lungs (determined by neutrophil counts in bronchoalveolar lavage fluid; 97.7 +/- 0.52% reduction) and peritoneal cavity (determined by neutrophil counts in peritoneal lavage fluid; 98.4 +/- 1.29% reduction). Fucoidin treatment also increased the systemic neutrophil count. These results suggest that the inhibition of leukocyte rolling, which may be a primary function of fucoidin, leads to a reduction of neutrophil accumulation at inflammatory sites, which may be beneficial for attenuating neutrophil-mediated tissue injury.

Animals↗
PubMed1996

A prospective study of bronchoscopy for endotracheobronchial tuberculosis.

To clarify the role of bronchoscopy for endotracheobronchial tuberculosis (EBTB), we performed a prospective study in 45 patients with active pulmonary tuberculosis, in 15 (33%) of whom bronchoscopic findings related to EBTB were seen. The findings were classified into six types:edematous hyperemic, submucosal nodule, ulcerative (shallow and deep), polypoid, cicatrical, and compression type. Each of these types was related to the healing process and outcome after antituberculosis chemotherapy. Serial bronchoscopy revealed that lesions less advanced than the deep ulcerative type responded to chemotherapy; the deep ulcerative and polypoid types progressed to cicatrical bronchostenosis despite chemotherapy. In the follow-up of patients with lesions of the deep ulcerative and polypoid types, serial bronchoscopy after chemotherapy is recommended; these patients also require adjunctive therapy to prevent cicatrical bronchostenosis.

Biopsy↗