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Biomedical subjects

Y Asano

Publications and source records attributed to Y Asano.

At least 271 records · Page 15Linked to original sources
PubMed1999

[Bacteriological and clinical break points: evaluation of the usefulness of cefozopran based on MIC].

Drug sensitivity of clinically isolated bacteria to cefozopran (CZOP), which is a new cephem antibiotic, was investigated, and the usefulness of the drug was evaluated from the viewpoint of bacteriological and clinical (pneumonia) break points. The following results were obtained. 1. According to bacteriological break points, methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus spp. showed low sensitivity to cefozopran (CZOP). However, the sensitivity of methicillin-sensitive Staphylococcus aureus (MSSA), E. coli, and Klebsiella spp., which are often isolated as pathogens of common infections, was 100%, that of Enterobacter spp., Serratia sp., and Citrobacter sp. was 90% or higher, and that of Pseudomonas aeruginosa was 80% or higher; the values were comparable to or better than those for ceftazidime (CAZ). These results suggest a expanded antibacterial spectrum and enhanced antibacterial potency of CZOP. 2. The estimated response rate of pneumonia to CZOP was 87.5% in outpatients and 51.9% in inpatients. Therefore, CZOP is considered to be one of the first choices especially in outpatient empiric therapy.

Cephalosporins↗
PubMed1999

[Sense of coherence, stressful life events and psychological health].

Aaron Antonovsky's Sense of Coherence (SOC), as a stable disposition of personality that serves as a major coping resource for the preservation of health, has been widely used in many studies. However, few empirical studies are conducted on the concept of SOC. We examined the stability of SOC and the buffering effect of SOC on the psychological health in dealing with stressful life events. The subjects were 200 adults randomly selected in Tokyo, and follow-up survey was conducted one year after the first survey. Goldberg's General Health Questionnaire (GHQ) was used for assessing psychological health. Antonovsky's SOC scale was translated into Japanese (and reverse translated) in this study. The test-retest reliability of SOC scale was 0.78. Cronbach's alpha was 0.91. The factors related to the SOC supported previous findings and Antonovsky's theory about the positive correlation with educational and economic status. In the follow-up survey, the subjects were also asked about the experience of 56 stressful life events (SLE) composed of four aspects of life during the previous year: personal, family, work and environment. The SLE was assessed through the total number and the weighted score. Contrary to the theory, the results showed that the SOC score has no intra-individual stability. The mean score of SOC in 1998 was 131.1 +/- 23.9, significantly lower than that in the previous year. When the subjects were divided into two groups based on a median 1997 score, the effect of SLE negatively affected SOC scores after one year among those who had a low SOC, although this effect was not observed among those who had a high SOC. The effect of SLE on changes of SOC was stronger among men compared to women. Also, the results showed the SOC was positively related to psychological health, and the buffering effect of SOC on the psychological health in dealing with stressful life events was only observed among men. Findings in this study suggest that SOC is variable for those with weak SOC if they experienced stressful life events. Also, the stressful life events differentially affect the SOC among men and women. The buffering effect was not sufficiently proven in this study. Methodological issues to confirm Antonovsky's theory are also presented.

Adult↗
PubMed1999

[A case of malignant hypertension in whom steroid improved renal function].

We report a case whose renal failure was due to malignant hypertension and in whom steroid facilitated the recovery of renal function. The patient, a 41-year-old man, was admitted to our hospital because of malaise and macrohematuria. On admission, his blood pressure was 270/160 mmHg. The plasma renin activity (PRA) and aldosterone were markedly elevated. Chest X-ray, echo cardiography and electrocardiogram revealed marked hypertrophy. Hypertensive retinopathy and arteriosclerotic change were noted on ophthalmoscopy. Because of renal dysfunction (blood urea nitrogen 45.6 mg/dl, serum creatinine 4.9 mg/dl with massive proteinuria and increased FENa, renal biopsy was performed on the 8th clinical day. The specimens showed slight proliferation of mesangial cells with mesangiolysis and interstitial cell infiltration, in addition to marked arteriosclerosis and partial collapse of the glomerular tuft. After the administration of a Ca antagonist and angiotensin converting enzyme inhibitor (ACE-I), his mean blood pressure decreased to 100-130 mmHg, and urinary protein decreased as well. Nevertheless, renal dysfunction remained unchanged during the following 3 weeks. Thus, prednisolone (PSL, 30 mg/day) was administered on the 22nd clinical day and renal function improved thereafter without a significant change in blood pressure. The improved renal function was maintained after PSL tapered off on the 184th clinical day. It is suggested that PSL might be the therapy of choice in malignant hypertension, when the renal function has not been improved by anti-hypertensive treatment alone.

Adult↗
PubMed1999

Pediatric admission for vaccine preventable diseases: a 5-year survey from 1994 to 1998 in Aichi Prefecture.

Several infectious childhood diseases can be prevented by vaccination. A survey of hospital admissions for such diseases was conducted in Aichi Prefecture over 5 years beginning in 1994. A questionnaire was sent annually to hospitals with 100 or more beds to obtain information on pediatric patients requiring hospitalization for 10 vaccine preventable diseases. Information was obtained on 3,953 patients. Most admissions were for measles (49%), followed by mumps, chickenpox, pertussis, rubella, and tuberculosis. Over half of the patients were under 3 years old, with 20% aged under 12 months, 25% aged from 12 months to 2 years, and 10% aged from 2 to 3 years. The average hospital stay was longest for tuberculosis and pertussis, and was around 1 week for the other diseases. Familial transmission was the most common source of infection identified. The only death was an unvaccinated patient with measles pneumonia. Sequelae were reported at the time of discharge in 15 patients (0.4%), and were permanent in some cases. Some 96% of the patients surveyed were unvaccinated against the disease causing hospitalization. The fact that there were 14 patients with sequelae and the one patient who died were unvaccinated, emphasizes the need to promote vaccination.

Adolescent↗
PubMed1998

Quantification of effects of global ischemia on dynamics of ventricular fibrillation in isolated rabbit heart.

BACKGROUND: Ventricular fibrillation (VF) leads to global ischemia of the heart. After 1 to 2 minutes of onset, the VF rate decreases and appears more organized. The objectives of this study were to determine the effects of no-flow global ischemia on nonlinear wave dynamics and establish the mechanism of ischemia-induced slowing of the VF rate. METHODS AND RESULTS: Activation patterns of VF in the Langendorff-perfused rabbit heart were studied with the use of 2 protocols: (1) 15 minutes of no-flow global ischemia followed by reperfusion (n=7) and (2) decreased excitability induced by perfusion with 5 micromol/L of tetrodotoxin (TTX) followed by washout (n=3). Video imaging ( approximately 7500 pixels per frame; 240 frames per second) with a voltage-sensitive dye, ECG, and signal processing (fast Fourier transform) were used for analysis. The dominant frequency of VF decreased from 13.5+/-1.3 during control to 9.3+/-1.4 Hz at 5 minutes of global ischemia (P<0.02). The dominant frequency decreased from 13.9+/-1.1 during control to 7.0+/-0.3 Hz at 2 minutes of TTX infusion (P<0.001). The rotation period of rotors on the epicardial surface (n=27) strongly correlated with the inverse dominant frequency of the corresponding episode of VF (R2=0. 93). The core area, measured for 27 transiently appearing rotors, was 5.3+/-0.7 mm2 during control. A remarkable increase in core area was observed both during global ischemia (13.6+/-1.7 mm2; P<0.001) and TTX perfusion (16.8+/-3.6 mm2; P<0.001). Density of wave fronts decreased during both global ischemia (P<0.002) and TTX perfusion (P<0.002) compared with control. CONCLUSIONS: This study suggests that rotating spiral waves are most likely the underlying mechanism of VF and contribute to its frequency content. Ischemia-induced decrease in the VF rate results from an increase in the rotation period of spiral waves that occurs secondary to an increase in their core area. Remarkably, similar findings in the TTX protocol suggest that reduced excitability during ischemia is an important underlying mechanism for the changes seen.

Animals↗
PubMed1998

Human ecalectin, a variant of human galectin-9, is a novel eosinophil chemoattractant produced by T lymphocytes.

A 1.6-kilobase pair cDNA was isolated from a human T-cell-derived expression library that encodes a novel eosinophil chemoattractant (designated ecalectin) expressed during allergic and parasitic responses. Based on its deduced amino acid sequence, ecalectin is a 36-kDa protein consisting of 323 amino acids. Although ecalectin lacks a hydrophobic signal peptide, it is secreted from mammalian cells. Ecalectin is not related to any known cytokine or chemokine but rather is a variant of human galectin-9, a member of the large family of animal lectins that have affinity for beta-galactosides. Recombinant ecalectin, expressed in COS cells and insect cells, exhibited potent eosinophil chemoattractant activity and attracted eosinophils in vitro and in vivo in a dose-dependent manner but not neutrophils, lymphocytes, or monocytes. The finding that the ecalectin transcript is present in abundance in various lymphatic tissues and that its expression increases substantially in antigen-activated peripheral blood mononuclear cells suggests that ecalectin is an important T-cell-derived regulator of eosinophil recruitment in tissues during inflammatory reactions. We believe that this is the first report of the expression of an immunoregulatory galectin expressed by a T-cell line that is selective for eosinophils.

Amino Acid Sequence↗
PubMed1998

Four cases of human herpesvirus 6 variant B infection after pediatric liver transplantation.

BACKGROUND: Little is known about human herpesvirus (HHV)-6 infection after liver transplantation. We present our experiences with four cases of HHV-6 infection after liver transplantation from living related donors. METHODS: Peripheral blood was collected from four donor and recipient pairs at the time of transplantation and biweekly from the recipients after transplantation. We attempted to isolate HHV-6 and measure antibody titers to HHV-6 and HHV-7. RESULTS: HHV-6 was isolated from four recipients approximately 2 weeks after transplantation. A significant rise in HHV-6 antibody titers was observed in four recipients at some point in their course, whereas HHV-7 antibody titers were increased in one recipient. Four isolates were variant B. When HHV-6 was isolated, all recipients had an unexplained fever. CONCLUSIONS: HHV-6 variant B infection after pediatric liver transplantation was confirmed. HHV-6 infection occurred approximately 2 weeks after transplantation. Moreover, there appears to be an association between HHV-6 infection and unexplained fever.

Antibodies, Viral↗
PubMed1998

Shielding design calculation for SPring-8 beamlines using STAC8.

The beamlines of SPring-8 are classified by synchrotron radiation source into undulator, wiggler and bending-magnet beamlines for safety analysis. The shielding design calculations for synchrotron radiation are performed with a new shielding design code, STAC8, taking into consideration the linear-polarization effect, the slant length of the shield hutch wall and the build-up effect as functions of scattering angle and azimuthal angle.

Journal Article↗
PubMed1998

Effects of hyperosmolality on Na, K-ATPase gene expression in vascular smooth muscle cells.

Cultured vascular smooth muscle cells (VSMC) from rat thoracic aortas were exposed to hyperosmotic media to determine the effects on Na, K-ATPase alpha1- and beta1-mRNA expression. Hyperosmotic media (500 mOsm/kgH2O) supplemented with glucose or mannitol increased alpha1-mRNA levels threefold at 24 hr and beta1-mRNA levels sevenfold at 12 hr. In sharp contrast, hyperosmotic urea medium had no effect at any time. Both the protein synthesis inhibitor cycloheximide and the RNA transcription inhibitor actinomycin D reduced alpha1- and beta1-mRNA upregulation induced by hyperosmotic glucose or mannitol media. Protein kinase C (PKC) inhibitors (staurosporine A or calphostin C) or tyrosine kinase (TK) inhibitors (genistein or herbimycin A) had no effect on the alpha1-mRNA upregulation induced by hyperosmotic glucose or mannitol media. Hyperosmotic glucose or mannitol media (500 mOsm/kgH2O) significantly increased alpha1- and beta1-subunit protein levels and Na, K-ATPase activity, whereas hyperosmotic urea medium had no effect. Transfection experiments with the 5'-flanking sequences of the alpha1- or beta1-subunit genes linked to the luciferase reporter gene revealed that hyperosmolar glucose medium increased luciferase activity 2.9- and 3.7-fold, respectively. Similarly, hyperosmotic mannitol medium increased such activity 2.7- and 3.4-fold, respectively. These results demonstrate that: (i) hyperosmolality induced by the poorly permeating solutes (glucose and mannitol) stimulates alpha1- and beta1-mRNA accumulation, alpha1- and beta1-subunit protein accumulation, and Na, K-ATPase activity, whereas the rapidly permeating solute (urea) has no effect; (ii) the upregulation of alpha1- and beta1-mRNA in response to hyperosmotic glucose or mannitol media requires, at least in part, de novo synthesis of intermediate regulatory proteins; (iii) the hyperosmolality-induced alpha1-mRNA upregulation occurs through PKC- and TK-independent mechanisms, whereas the hyperosmolality-induced beta1-mRNA upregulation occurs through activation of PKC and TK; and (iv) hyperosmolality induced by glucose or mannitol increases promoter activities of the alpha1- and beta1-subunit genes.

Animals↗
PubMed1998

Crystallization of Arthrobacter sp. strain 1C N-(1-D-carboxyethyl)-L-norvaline dehydrogenase and its complex with NAD+

The novel NAD+-linked opine dehydrogenase from a soil isolate Arthrobacter sp. strain 1C belongs to an enzyme superfamily whose members exhibit quite diverse substrate specificites. Crystals of this opine dehydrogenase, obtained in the presence or absence of co-factor and substrates, have been shown to diffract to beyond 1.8 Å resolution. X-ray precession photographs have established that the crystals belong to space group P21212, with cell parameters a = 104.9, b = 80.0, c = 45.5 Å and a single subunit in the asymmetric unit. The elucidation of the three-dimensional structure of this enzyme will provide a structural framework for this novel class of dehydrogenases to enable a comparison to be made with other enzyme families and also as the basis for mutagenesis experiments directed towards the production of natural and synthetic opine-type compounds containing two chiral centres.

Journal Article↗
PubMed1998

Crystallization of Arthrobacter sp. strain 1C N-(1-D-carboxyethyl)-L- norvaline dehydrogenase and its complex with NAD+.

The novel NAD+-linked opine dehydrogenase from a soil isolate Arthrobacter sp. strain 1C belongs to an enzyme superfamily whose members exhibit quite diverse substrate specificities. Crystals of this opine dehydrogenase, obtained in the presence or absence of co-factor and substrates, have been shown to diffract to beyond 1.8 A resolution. X-ray precession photographs have established that the crystals belong to space group P21212, with cell parameters a = 104.9, b = 80.0, c = 45.5 A and a single subunit in the asymmetric unit. The elucidation of the three-dimensional structure of this enzyme will provide a structural framework for this novel class of dehydrogenases to enable a comparison to be made with other enzyme families and also as the basis for mutagenesis experiments directed towards the production of natural and synthetic opine-type compounds containing two chiral centres.

Arthrobacter↗
PubMed1998

Thermostable phenylalanine dehydrogenase from a mesophilic microbacterium sp. strain DM 86-1

Bacteria that produced NAD+-dependent phenylalanine dehydrogenase (EC 1.4.1.20) were selected among l-methionine utilizers isolated from soil. A bacterial strain showing phenylalanine dehydrogenase activity was chosen and classified in the genus Microbacterium. Phenylalanine dehydrogenase was purified from the crude extract of Microbacterium sp. strain DM 86-1 (TPU 3592) to homogeneity as judged by SDS-polyacrylamide disc gel electrophoresis. The enzyme has an isoelectric point of 5.8 and a relative molecular weight (Mr) of approximately 330,000. The enzyme is composed of eight identical subunits with an Mr of approximately 41,000. The apparent Km values for l-phenylalanine and NAD+ were calculated to be 0.10 mM and 0.20 mM, respectively. No loss of the enzyme activity was observed upon incubation at 55 degrees C for 10 min.

Journal Article↗
PubMed1998

Isolation and characterization of a bacterium possessing a novel aldoxime-dehydration activity and nitrile-degrading enzymes.

A bacterial strain capable of utilizing E-pyridine-3-aldoxime as a nitrogen source was isolated from soil after a 4-month acclimation period and was identified as Rhodococcus sp. The strain contained a novel aldoxime dehydration activity that catalyzed a stoichiometric dehydration of E-pyridine-3-aldoxime to form 3-cyanopyridine. The enzyme activity was induced by various aldoximes and nitriles. The strain metabolized the aldoxime as follows: E-pyridine-3-aldoxime was dehydrated to form 3-cyanopyridine, which was converted to nicotinamide by a nitrile hydratase, and the nicotinamide was successively hydrolyzed to nicotinic acid by an amidase.

Amidohydrolases↗
PubMed1998

Cloning, nucleotide sequencing, and expression of the 3-methylaspartate ammonia-lyase gene from Citrobacter amalonaticus strain YG-1002.

The gene coding for 3-methylaspartate ammonia-lyase (3-methylaspartase, MAL, EC 4.3.1.2) from Citrobacter amalonaticus strain YG-1002 (TPU 6323) was cloned onto plasmid pBluescript II KS(+), and the nucleotide sequence of the 1239-bp open reading frame (ORF), consisting of 413 codons, was identified as the mal gene coding for MAL. The predicted polypeptide has 62.5% identity with MAL from the obligate anaerobe, Clostridium tetanomorphum NCIMB 11547. ORF1, which showed 58.6% and 58.8% identities with subunit E of the glutamate mutases of C. tetanomorphum and Clostridium cochlearium respectively, was found in the upstream region of the mal gene. An expression plasmid pMALCA3 (5.4 kb), in which the mal gene was expressed under control of the lac promoter on the vector, was constructed. With feeding of 1 mM isopropyl beta-D-thiogalactopyranoside, the amount of the enzyme in a cell-free extract of the transformant, E. coli JM109/pMALCA3, was elevated to 51,800 units/l culture, which is about 50-fold that of C. amalonaticus strain YG-1002. It was calculated that the enzyme comprised over 40% of the total extractable cellular proteins. The enzyme produced by the E. coli transformant was purified in a crystalline form and shown to be identical to that of the wild-type strain with respect to specific activity, molecular mass, subunit structure, enzymological properties, and N-terminal amino acid sequences.

Amino Acid Sequence↗
PubMed1998

Growth inhibition of leukemic cells by (-)-epigallocatechin gallate, the main constituent of green tea.

In this report, we presented the results that EGCG, the main constituent of the polyphenols present in Japanese green tea inhibited growth of leukemic cell lines of both human and mice. The proliferation of human leukemic cell lines and mouse NFS60 cell line was inhibited by EGCG. Sensitivity of each line to EGCG was different, and more than 50% of DNA synthesis was reduced in all the cell lines in the presence of 50 microM EGCG. On the other hand, normal hematopoietic progenitor cells retained their natural function of supplying mature cells of various lineages in the presence of less than 10 microM EGCG in vitro. Even in the presence of 100 microM EGCG, half the colonies containing all the lineages of cells were developed. All the dead cells of each line showed characteristics of apoptosis, which might be due to inhibition by EGCG of growth factors' signaling. Besides anticarcinogenic activity, EGCG is expected to have a new function for leukemia therapy without side effects.

Animals↗
PubMed1998

Crystal structure and active site location of N-(1-D-carboxylethyl)-L-norvaline dehydrogenase.

Opine dehydrogenases catalyze the NAD(P)H-dependent reversible reaction to form opines that contain two asymmetric centers exhibiting either (L,L) or (D,L) stereochemistry. The first structure of a (D,L) superfamily member, N-(1-D-carboxylethyl)-L-norvaline dehydrogenase (CENDH) from Arthrobacter sp. strain 1C, has been determined at 1.8 A resolution and the location of the bound nucleotide coenzyme has been identified. Six conserved residues cluster in the cleft between the enzyme's two domains, close to the nucleotide binding site, and are presumed to define the enzyme's catalytic machinery. Conservation of a His-Asp pair as part of this cluster suggests that the enzyme mechanism is related to the 2-hydroxy acid dehydrogenases. The pattern of sequence conservation and substitution between members of this enzyme family has permitted the tentative location of the residues that define their differential substrate specificities.

Amino Acid Sequence↗