Biomedical subjects

K Abe

Publications and source records attributed to K Abe.

At least 451 records · Page 25Linked to original sources

PubMed2000

The entire nucleotide sequence of two hepatitis G virus isolates belonging to a novel genotype: isolation in Myanmar and Vietnam.

A novel genotype of hepatitis G virus (HGV) was recently identified in sera of subjects from countries in South-East Asia. These isolates were recovered from serum of Myanmarese (designated HGV-MY14) and Vietnamese (designated HGV-VT48) subjects, respectively. To characterize the viral genome in more detail, the full-length nucleotide sequence of the two different HGV isolates belonging to the novel genotype was cloned. Both HGV isolates were composed of 9228 nt and had a single open reading frame spanning 8529 nt and encoding 2843 aa residues. The isolates differed from previously reported HGV/GBV-C isolates types 1 to 3 by 13-15% (nucleotide sequence) and 4-6% (amino acid sequence). The putative core region of both isolates was not clearly identifiable as it consisted of only 16 aa residues. Based on phylogenetic analysis of full-length genome sequences and 5'-UTR sequences, HGV-MY14 and HGV-VT48 isolates can be classified as a novel genotype, designated type 4.

Adolescent↗

PubMed2000

Bromomalonic-acid-induced transition from trigger wave to big wave in the Belousov-Zhabotinsky reaction

The Marangoni effects on chemical waves in the ferroin-catalyzed Belousov-Zhabotinsky reaction were studied. The main purpose of the present study was to understand the mechanism of the big wave, an accelerative chemical wave involving surface-tension-driven fluid motions. Spatiotemporal variations of surface tension caused by a chemical wave were measured using the Wilhelmy method. The transition from conventional trigger waves to big waves, due to a concentration change of bromomalonic acid, was observed. The strong surface activity of the bromomalonic acid which was responsible for the transition was also observed. It led to an acceleration of the big waves through the Marangoni effect.

Journal Article↗

PubMed2000

Kink-breather solution in the weakly discrete Frenkel-Kontorova model

The discrete Frenkel-Kontorova model, having the sine-Gordon equation as the continuous analog, was investigated numerically at a small degree of discreteness. Interaction between a kink and a breather in a discrete system was compared with the exact three-soliton solution to the continuous sine-Gordon equation. Nontrivial effects of discreteness were found numerically. One is that a kink and a breather in the discrete system are mutually attractive quasiparticles, so they can be regarded as a three-soliton oscillatory system. The other is the energy exchange between a kink and a breather when their collision takes place in a vicinity of a separatrix solution to the continuous sine-Gordon equation. We have estimated numerically the kink-breather binding energy EB and the maximum possible exchange energy EE for different breather frequencies omega. The results suggest that there is a threshold breather frequency for the "spontaneous" breaking up of the three-soliton oscillatory system into a kink and a breather moving in opposite directions.

Journal Article↗

PubMed2000

Th1-Th2 cytokine kinetics in the bronchoalveolar lavage fluid of mice infected with Cryptococcus neoformans of different virulences.

Th1 immune response plays an important role in protection against infection with Cryptococcus neoformans in mice. We investigated the effect of virulence of C. neoformans on cytokine production in the lung of a mouse model of pulmonary cryptococcosis. BALB/c mice were inoculated intratracheally with a high or low virulence strain of C. neoformans, followed by serial measurements of Th1 and Th2 cytokine concentrations in the bronchoalveolar lavage (BAL) fluid using appropriate enzyme-linked immunosorbent assay kits. The number of colony-forming units (CFU) increased with time, and all mice infected with the highly virulent strain were dead at 28 days after inoculation. In contrast, the number of microorganisms diminished with time in the mice infected with the low virulence strain during the 4-week study. The numbers of neutrophils and lymphocytes in the BAL fluid paralleled those of CFU. High neutrophil counts were observed in the BAL fluid of mice infected with the highly virulent strain, while lymphocyte counts were increased only in the later part of the study in mice infected with the high and low virulence strains. The concentrations of Th2 cytokine, interleukin (IL)-4 were significantly higher in mice infected with the highly virulent strain at days 14 and 21 of infection, whereas the level of Th1 cytokine, interferon-gamma, was significantly higher in the latter strain at days 7 and 14. Our results suggest that strain-specific difference in the organism's ability to induce (or evade) the host immune system contributes to the outcome of infection.

Animals↗

PubMed2000

Structure-activity relationships of sialogogic heptapeptides analogous to physalaemin.

OBJECTIVES: The rationale behind this study was to determine in detail which amino acids in physalaemin are crucial to its sialogogue activity, with a view of synthesizing new sialogogues which might be of use in the treatment of dry mouth. METHODS: With the progressive elimination of amino acids, one by one, from the C- and N-terminal regions, 126 heptapeptides were newly synthesized by the multipin peptide method, for comparison with II naturally occurring tachykinins. RESULTS: The C-terminal amide in position II was essential for salivation, but not the pyrolidine group or the N-terminal amino acid residues in positions I to 4. In 18 heptapeptides in which M in position II (MII) was replaced by another amino acid, one by one, none caused salivation. In 18 heptapeptides, in which L10 or G9 was replaced, three peptides caused salivation but none had significantly increased secretory activities. In 18 heptapeptides in which Y8 was replaced, four caused salivation but only one (I) had significantly increased secretory activity. In 18 heptapeptides in which F7 was replaced, only Y caused salivation but with significantly reduced secretory activity. In contrast, in 18 heptapeptides in which K6 and N5 were replaced, most caused salivation and some of them had significantly increased secretory activities. CONCLUSIONS: It is concluded that the sequence FYGLM-NH2 conserved in the C-terminal region of physalaemin is optimal, that amides in position II and F7 are very important for salivation, but that K6 and N5 can be replaced by some other amino acids, resulting in increased secretory activities.

Amino Acids↗

PubMed2000

The complexity of TNF-related apoptosis-inducing ligand.

One of the major goals of researchers in the field of apoptosis is to understand the molecular mechanisms of the various components of the apoptotic pathways, with the hope to identify targets for novel cancer therapies. The discovery of a TNF-related, apoptosis-inducing ligand, TRAIL, that kills transformed cells with great specificity in vitro, has provided the hope that TRAIL may be used to induce cell death in tumor cells without affecting normal tissues. However, TRAIL signaling is very complex and a clear understanding of its function is necessary before it can be used in cancer therapy. Complexity of TRAIL-induced signaling is apparent from its ubiquitous expression, its ability to interact with five receptors, and its tumor-selective induction of apoptosis. The signaling events that mediate the tumor selectivity of TRAIL-induced apoptosis and the biological functions of each of the TRAIL receptors are not well characterized. This review will focus on the complexity of TRAIL and the role of c-FLIP in mediating TRAIL function.

Adaptor Proteins, Signal Transducing↗

PubMed2000

High prevalence of TT virus DNA in human saliva and semen.

Using the PCR assay, we found a high prevalence of TT virus (TTV) DNA in saliva and semen from patients who were seropositive for TTV. This finding suggests that the presence of TTV in body fluids other than serum may affect the routes of viral transmission.

Adult↗

PubMed2000

TT virus infection in nonhuman primates and characterization of the viral genome: identification of simian TT virus isolates.

Newly discovered TT virus (TTV) is widely distributed in human populations. To understand more about the relationship between TTV and its hosts, we tested 400 sera from various nonhuman primates for the presence of TTV DNA by PCR assay. We collected serum samples from 24 different species of nonhuman primates. TTV DNA was determined by PCR with primers designed from the 5'-end region of the TTV genome. Nucleotide sequencing and phylogenetic analysis of viral genomes were also performed. TTV DNA was detected in 87 of 98 (89%) chimpanzees and 3 of 21 (14%) crab-eating macaques. Nucleotide sequences of the PCR products obtained from both animals were 80 to 100% identical between two species. In contrast, the sequences differed from TTV isolates in humans by 24 to 33% at the nucleotide level and 36 to 50% at the amino acid level. Phylogenetic analysis demonstrated that all TTV isolates obtained from simians were distinct from the human TTV isolates. Furthermore, TTV in simians, but not in humans, was classified into three different genotypes. Our results indicate that TTV in simians represents a group different from, but closely related to, TTV in humans. From these results, we tentatively named this TTV simian TTV (s-TTV). The existence of the s-TTV will be important in determining the origin, nature, and transmission of human TTV and may provide useful animal models for studies of the infection and pathogenesis of this new DNA virus.

Amino Acid Sequence↗

PubMed2000

Introduction of the interleukin-10 gene into mice inhibited bleomycin-induced lung injury in vivo.

Interleukin (IL)-10 has been shown to reduce many inflammatory reactions. We investigated the in vivo effects of IL-10 on a bleomycin-induced lung injury model. Hemagglutinating virus of Japan (HVJ)-liposomes containing a human IL-10 expression vector (hIL10-HVJ) or a balanced salt solution as a control (Cont-HVJ) was intraperitoneally injected into mice on day -3. This was followed by intratracheal instillation of bleomycin (0.8 mg/kg) on day 0. Myeloperoxidase activity of bronchoalveolar lavage fluid and tumor necrosis factor-alpha mRNA expression in bronchoalveolar lavage fluid cells on day 7 and hydroxyproline content of the whole lung on day 21 were inhibited significantly by hIL10-HVJ treatment. However, Cont-HVJ treatment could not suppress any of these parameters. We also examined the in vitro effects of IL-10 on the human lung fibroblast cell line WI-38. IL-10 significantly reduced constitutive and transforming growth factor-beta-stimulated type I collagen mRNA expression. However, IL-10 did not affect the proliferation of WI-38 cells induced by platelet-derived growth factor. These data suggested that exogenous IL-10 may be useful in the treatment of pulmonary fibrosis.

Animals↗

PubMed2000

Fatigue in patients with Parkinson's disease.

Purpose: Fatigue is a complaint frequently encountered among patients with Parkinson's disease (PD), however, the pathophysiological mechanism remains unclear. Methods: We evaluated fatigue in 26 patients clinically diagnosed to have PD (16 men, 10 women) and age- and sex- matched 26 controls (16 men, 10 women) without neurological deficits by using a fatigue scale. In addition to neurological and neuropsychological examinations, all patients underwent MRI and SPECT using 99mTc-HMPAO. Results: Patients with PD had normal cognitive function as judged by the MMSE, but showed significantly high scores with the fatigue and depression scales in comparison to controls (p<0.05). There was no significant correlation between the depression scale and the fatigue scale, or between the degree of disability and the fatigue scale in patients with PD, although a significant correlation existed between the depression scale and the fatigue scale in controls. With SPECT, a significant correlation was found between the fatigue scale and the reduction of perfusion in the frontal lobe (p<0.05) in patients with PD. Conclusions: The present study suggested that sense of fatigue in patients with PD might be associated with frontal lobe dysfunction.

Journal Article↗

PubMed2000

Immunoglobulin G and M hepatitis C virus core antibody (JCC.2) response in chimpanzees infected experimentally with hepatitis C virus.

OBJECTIVE: To evaluate changes in serum immunoglobulin M (IgM) and G (IgG) hepatitis C virus (HCV) core antibodies after HCV infection in acute hepatitis C. METHODS: Serum HCV RNA and IgM and IgG HCV core antibodies were investigated using sera sequentially sampled from three chimpanzees experimentally infected with HCV. Serum IgG HCV core antibody titer was measured using a JCC.2 enzyme-linked immunosorbent assay (ELISA) kit (Chemo-Sera-Therapeutic Research Center, Kumamoto, Japan). IgM core antibody titer was measured using horseradish peroxidase-labeled monoclonal anti-human IgM as the secondary antibody for the JCC.2 ELISA kit. Serum HCV RNA was detected using the 5' noncoding region as the primer according to the reverse transcriptase (RT) nested polymerase chain reaction (PCR) and competitive RT-PCR method. RESULTS: IgM JCC.2 antibody was detected when alanine aminotransferase (ALT) peaked, showing the closest correlation with the changes in ALT. A period during which IgM JCC.2 antibody was positive but HCV RNA as determined by RT-nested PCR was negative was observed after the elevation of ALT level. CONCLUSION: These results indicate the usefulness of detection of serum IgM JCC.2 antibody in making a definitive diagnosis of acute hepatitis C and the follow-up observation of hepatitis C.

Acute Disease↗

PubMed2000

Cyclin D1 and Cdk4 protein induction in motor neurons after transient spinal cord ischemia in rabbits.

BACKGROUND AND PURPOSE: The mechanism of spinal cord injury has been thought to be related to the vulnerability of spinal motor neuron cells against ischemia. However, the mechanisms of such vulnerability are not fully understood. We hypothesized that spinal motor neurons might be lost by programmed cell death and investigated a possible mechanism of neuronal death by detection of double-strand breaks in genomic DNA and immunohistochemical analysis for cyclin D1 and cyclin-dependent kinases (Cdk) 4. METHODS: We used a rabbit spinal cord ischemia model with a balloon catheter. Spinal cord was removed at 8 hours and 1, 2, and 7 days after 15 minutes of transient ischemia, and histological changes were studied with hematoxylin-eosin staining. In situ terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL), DNA fragment with gel electrophoresis, Western blot analysis for cyclin D1 and Cdk4, and temporal profiles of cyclin D1 and Cdk4 immunoreactivity were investigated. RESULTS: Most motor neurons were preserved until 2 days but were selectively lost at 7 days of reperfusion. Immunocytochemistry showed positive TUNEL selectively at 2 days of reperfusion in spinal motor neuron nuclei. Typical ladders of oligonucleosomal DNA fragments were detected at 2 days of reperfusion. Immunoreactivity of cyclin D1 and Cdk4 proteins was induced selectively at 8 hours in motor neuron nuclei, which eventually died. CONCLUSIONS: These results indicate that induction of cyclin D1 and Cdk4 may be implicated in programmed cell death change after transient spinal cord ischemia in rabbits.

Animals↗

PubMed2000

On the synthesis of brain-state-in-a-box neural models with application to associative memory.

In this article we present techniques for designing associative memories to be implemented by a class of synchronous discrete-time neural networks based on a generalization of the brain-state-in-a-box neural model. First, we address the local qualitative properties and global qualitative aspects of the class of neural networks considered. Our approach to the stability analysis of the equilibrium points of the network gives insight into the extent of the domain of attraction for the patterns to be stored as asymptotically stable equilibrium points and is useful in the analysis of the retrieval performance of the network and also for design purposes. By making use of the analysis results as constraints, the design for associative memory is performed by solving a constraint optimization problem whereby each of the stored patterns is guaranteed a substantial domain of attraction. The performance of the designed network is illustrated by means of three specific examples.

Association Learning↗

PubMed2000

Predominant role for C5b-9 in renal ischemia/reperfusion injury.

Previous work has indicated that complement is a mediator of ischemia/reperfusion (I/R) injury. To investigate the components of complement responsible for this effect, we examined a model of renal I/R injury in C3-, C4-, C5-, and C6-deficient mice. We occluded the renal arteries and veins (40-58 minutes) and, after reperfusion (0-72 hours), assessed renal structural and functional injury. C3-, C5-, and C6-deficient mice were protected from renal I/R injury, whereas C4-deficient mice were not protected. C6-deficient mice treated with antibody to block C5a generation showed no additional protection from I/R injury. Reconstitution with C6 alone restored the I/R injury in C6-deficient mice. Tubular epithelial cells were the main structures damaged by complement-mediated attack, and, in contrast, the renal vessels were spared. Neutrophil infiltration and myeloperoxidase activity were reduced in C-deficient mouse kidney, but by a similar extent in C3-deficient and C6-deficient mice. We conclude that the membrane attack complex of complement (in which C5 and C6 participate) may account for the effect of complement on mouse renal I/R injury. Neither C5a-mediated neutrophil infiltration nor the classic pathway, in which C4 participates, appears to contribute to I/R injury in this model. By contrast with other organs, such as the heart, the primary effect of complement in the ischemic area is on the parenchymal cell rather than the vascular endothelial cell. The membrane attack complex of complement is a potential target for prevention of I/R injury in this model.

Animals↗

PubMed2000

Influence of thoracoabdominal movement on pulmonary function in patients with Parkinson's disease: comparison with healthy subjects.

Patients with Parkinson's disease (PD) may develop pulmonary dysfunction, but the pathogenesis remains unclear. We investigated a correlation between thoracoabdominal movements and pulmonary function in seven patients with PD and 14 healthy controls. We measured vital capacity (VC) and forced vital capacity (FVC) using an autospirometer, and measured chest and abdominal movements using a respiratory inductance plethysmography by fixing transducers on the rib cage and umbilicus. Patients with PD had significantly decreased % VC (90.3 +/- 17.1 vs 105.8 +/- 13.9%), chest movement (271.3 +/- 79.6 vs. 375.2 +/- 126.7% VT) and abdominal movement (217.6 +/- 93.5 vs. 247.4 +/- 100.2% VT) with 100% VT being an average volume of chest and abdomen at rest during measurement of VC. Patients with PD also had significantly decreased % FVC (74.4 +/- 20.6 vs. 97.6 +/- 14.1%), chest movement (246.2 +/- 115.2 vs. 344.5 +/- 126.4% VT) and abdominal movement (160.3 +/- 105.6 vs 207.6 +/- 104.7% VT) with 100% VT being an average volume of chest and abdomen at rest during forced maximal inspiration. Based on the results, we conclude that a reduction of % VC in patients with PD correlated with chest movements, while a reduction of % FVC correlated with abdominal movement in patients with PD.

Abdomen↗

PubMed2000

Characteristics factor structures of the Japanese version of the State-Trait Anxiety Inventory: coexistence of positive-negative and state-trait factor structures.

Previous factor studies of the State-Trait Anxiety Inventory (STAI; Spielberger, Gorsuch, & Lushene, 1970) have reported certain typical factors that are state-trait (S-T) 2-factor solutions and positively-negatively (P-N) worded item 2-factor solutions in addition to 4-factor solutions (positively and negatively worded state factors, positively and negatively worded trait factors). We explored the possibility that these factor structures are included in a factor space. Responses to the Japanese version of the STAI in a sample of 848 male workers were factor analyzed. The first-order factors obtained from principal-component analysis were almost equal to the previous 4 factors, except for a minor factor, and their second-order factors were the P-N factors. However, the S-T factors were also obtained from the same first-order factors by the oblique Procrustes rotation. Moreover, coexistence of these two 2-factor structures was determined in the same factor space by the orthogonal Procrustes rotation.

Adult↗

PubMed2000

Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the expression of follicle-stimulating hormone receptors during cell differentiation in cultured granulosa cells.

Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) is a common environmental pollutant causing public concern. Using a cell culture system derived from rat granulosa cells that provides unique advantages for studying the molecular mechanisms underlying the action of TCDD, the influences of TCDD on FSH receptor (FSH-R) induction were examined. The treatment with FSH produced, as expected, a substantial increase in specific FSH-R expression, whereas concurrent treatment with the environmental amount of TCDD (10 pM) resulted in a significant decrease in FSH-R after being cultured from 24-72 h. Cotreatment with FSH (30 ng/ml) and increasing doses of TCDD inhibited the levels of FSH-induced FSH-R messenger RNA (mRNA) in a dose-dependent manner. Treatment with 8-Br-cAMP (1 mM) produced a significant increase in FSH-R mRNA; concurrent treatment with TCDD (10 pM) produced a significant attenuation of 8-Br-cAMP action. These findings suggest that the ability of TCDD to interfere with FSH action, as regards the induction of FSH-Rs, is exerted at sites distal to those involved in cAMP generation. Because a single transcript of 5.2 kb was seen for the Ah receptor in this granulosa cell system, the effects of TCDD may be mediated by this specific receptor. The rates of FSH-R mRNA gene transcription, assessed by nuclear run-on transcription assay, were decreased by the addition of TCDD. The effect of TCDD on FSH-R mRNA stability was determined by measuring the decay of FSH-R mRNA under conditions known to inhibit transcription. The decay curve for the 2.4-kb FSH-R mRNA transcript was not significantly changed after the addition of TCDD. These findings showed that the effect of TCDD on FSH-R mRNA was, at least in part, the result of decreased transcription.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2000

Involvement of Na+-K+ pump in L-glutamate clearance by cultured rat cortical astrocytes.

When L-glutamate (150 microM) was added to rat cortical astrocyte cultures and incubated for 1-3 h, the extracellular L-glutamate concentration declined with time. The time-dependent decline of extracellular L-glutamate concentration was due to the uptake of L-glutamate by astrocytes. The clearance of extracellular L-glutamate by astrocytes was partly slowed down by replacing NaCl with choline chloride or LiCl in the extracellular medium or by adding KCI, and was completely blocked by replacing NaCl with KCI. Furthermore, the L-glutamate clearance was blocked by Na+-K+ pump inhibitors, ouabain and vanadate, but was not affected by Na+ channel modulators nor by K+ channel blockers. These results suggest that the clearance of extracellular L-glutamate by astrocytes is dependent on both Na+ and K+ gradients across the plasma membrane, and that the Na+-K+ pump plays a role in the regulation of L-glutamate clearance.

Animals↗