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Biomedical subjects

A Nakamura

Publications and source records attributed to A Nakamura.

At least 145 records · Page 8Linked to original sources
PubMed2000

Sustained viral response is rarely achieved in patients with high viral load of HCV RNA by excessive interferon therapy.

Adequate dosing of interferon (IFN) and its cost-effectiveness for sustained virological response were evaluated in relation to viral load and subtype. Prospective analysis of IFN therapy on 326 patients with chronic hepatitis C free from cirrhosis was performed using 9 or 6 million unit (MU) of IFN for six months daily and/or three times a week. Sustained virological response was achieved in 50-94% of patients with < or =2 x 10(4) copies/ml (competitive RT-PCR) or <100 x 10(3) copies/ml (Amplicor monitor) of HCV RNA by 468-1206 MU of IFN, but response was only 0-25% of the patients with > or =2 x 10(5.5) copies/ml (competitive RT-PCR) or >200 x 10(3) copies/ml (Amplicor monitor), even with 468-1206 MU of IFN. A high sustained rate was demonstrated in patients with 100-200 x 10(3) copies/ml of HCV RNA by 901-1206 MU of IFN, in comparison to that with < or =900 MU of IFN. Multivariate analysis showed that IFN dose had a significant value for the efficacy of IFN therapy in patients presenting 100-200 x 10(3) copies/ml of HCV RNA. Cost efficacy analysis indicated that it cost approximately $10,000, $26,000, and $50,000-227,000 for one person-viral eradication in the patients with <100, 100-200, and >200 x 10(3) copies/ml, respectively. High-dose IFN is only cost effective in patients with intermediate viral loads, and IFN therapy could be recommended in patients with <200 x 10(3) copies/ml of HCV RNA.

Adolescent↗
PubMed2000

Dynamic topography of pattern visual evoked potentials (PVEP) in psychogenic visual loss patients.

We investigated to measure the objective visual acuity using pattern visual evoked potentials (PVEP) to help the diagnosis with psychogenic visual loss (PVL) who ranged in age from 7 to 14 years old. Pattern stimuli consisted of black and white checkerboard patterns (39, 26, 15 and 9') with a visual angle of 8 degrees and a contrast level of 15%. The pattern reversal frequency was 0.7 Hz. This resulted in an average of 100 PVEP per session. Visual acuity of 0.1 was consistent with the 39' pattern, 0.2 with the 26' pattern, 0.5 with the 15' pattern, and 1.0 with the 9' pattern. As the results, five PVL patients could measure visual acuity with this method in the present study. The PVEP is useful in evaluating the visual acuity and helped to diagnose the PVL patients. In addition we used the dynamic topography to study the difference in the results of the PVEP. The dynamic topography obtained from the results of the PVEP was analyzed. The flow type of the P100 component diverged into three types (separated type, hollow type and localized type) in the PVL patients and the normal children. The localized type was observed in 59.1% of normal children and in 56.3% of PVL patients. While the separated type was shown in 6.8% of normal children and in 8.3% of PVL patients. There were not significant differences between the PVL patients and the normal children in each type.

Adolescent↗
PubMed2000

A2-Pancortins (Pancortin-3 and -4) are the dominant pancortins during neocortical development.

We have identified a novel mouse gene named pancortin that is expressed dominantly in the mature cerebral cortex. This gene produces four different species of proteins, Pancortin-1-4, sharing a common region in the middle of their structure with two variations at the N-terminal (A1 or A2 part) and C-terminal (C1 or C2 part) sides, respectively. In the present study, we showed that expression of mRNAs for A2-Pancortins (Pancortin species that contain the A2 part, i.e., Pancortin-3 and -4) is more dominant than that of mRNAs for A1-Pancortins (Pancortin species that contain the A1 part, i.e., Pancortin-1 and -2) in the prenatal mouse cerebral neocortex. Using western blot analysis, we found that substantial amounts of both A2-Pancortins were present in the prenatal cerebral neocortex and P19 cells after inducing neuronal differentiation. A2-Pancortins were still present in the cerebral neocortex of the adult, although their mRNAs were hardly detected. In contrast, the amount of A1-Pancortins did not increase after the third postnatal week in spite of their intense gene expression. Furthermore, we showed that recombinant Pancortin-3, one of the A2-Pancortins, was a secreted protein, in contrast to Pancortin-1 (one of the A1-Pancortins). These results suggest that A2-Pancortins are extracellular proteins essential for neuronal differentiation and that their molecular behavior is distinct from that of A1-Pancortins.

Alkaline Phosphatase↗
PubMed2000

Renal protective effect of troglitazone in Wistar fatty rats.

Although it is known that renal injury develops in obesity and diabetes mellitus, there have been no investigations examining the impact of insulin resistance per se on the development of renal injury. The present study was undertaken to examine whether insulin resistance and obesity influence urinary protein excretion (UPE) in female heminephrectomized Wistar fatty rats (WFRs). After 24 weeks of heminephrectomy in WFRs, the body weight ([BW], 465+/-18 g; n = 6), blood pressure (155+/-5 mm Hg), serum insulin to glucose ratio (1.31+/-0.39 microU/mg), and daily UPE (24+/-7 mg/d) were greater versus Wistar lean rats ([WLRs] 258+/-8 g, 134+/-1 mm Hg, 0.19+/-0.06 microU/mg, and 5+/-1 mg/d, respectively; n = 6), whereas blood glucose levels did not increase significantly. In WFRs, long-term (ie, 24 weeks) treatment with troglitazone, an insulin-sensitizing agent, improved the serum insulin to glucose ratio (0.17+/-0.09 microU/mg), reduced blood pressure (to 140+/-4 mm Hg), and decreased UPE (to 7+/-1 mg/d), although it had no effect on BW. Of note, with troglitazone treatment, the reduction in proteinuria preceded the correction of hypertension (ie, at week 12). In conclusion, our study suggests that insulin resistance per se causes proteinuria that does not appear to depend on blood pressure. Furthermore, long-term therapy with troglitazone may be a useful tool for the treatment of renal injury in the insulin-resistant condition.

Animals↗
PubMed2000

Digestibility of allergens extracted from natural rubber latex and vegetable foods.

BACKGROUND: Several cross-reactive allergens are now known to be involved in the defense responses of higher plants. Such proteins are drawing the attention of plant breeders because of their antimicrobial or stress-alleviating activities. Plants genetically modified to express defense-related proteins are being developed. The current concern is focused on the allergenicity of these intentionally expressed proteins. OBJECTIVE: It is believed that food allergens are proteins resistant to digestion. Digestibility tests have been accepted as an appropriate method for evaluating the allergenicity of newly introduced proteins. In this study we investigated the usefulness of this method for detecting allergens from natural rubber latex and vegetable foods. METHODS: Proteins were extracted from rubber latex, potato, and 5 kinds of fruits. Simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were used for the digestibility test. An aliquot of each digest was periodically withdrawn and analyzed. Allergens were detected with pooled sera from individuals with latex allergy or patients given a diagnosis of oral allergy syndrome. RESULTS: Most latex and vegetable food proteins were digested by the SGF within 4 minutes. Numerous allergens were also decomposed by the SGF within 8 minutes. Although vegetable food allergens were relatively stable in the SIF, kiwi allergens were substantially degraded by the SIF within 16 hours. CONCLUSION: The pronounced lability of the plant-derived allergens was thought to reflect the discrete sensitization and elicitation processes of patients with latex-fruit syndrome or oral allergy syndrome. These results indicate that the allergenicity of a newly expressed protein should be carefully evaluated according to not only its digestibility but also other important properties.

Allergens↗
PubMed2000

Functional delineation of the human occipito-temporal areas related to face and scene processing. A PET study.

By measuring regional cerebral blood flow using PET, we delineated the roles of the occipito-temporal regions activated by faces and scenes. We asked right-handed normal subjects to perform three tasks using facial images as visual stimuli: in the face familiar/unfamiliar discrimination (FF) task, they discriminated the faces of their friends and associates from unfamiliar ones; in the face direction discrimination (FD) task, they discriminated the direction of each unfamiliar face; in the dot location discrimination (DL) task, they discriminated the location of a red dot on a scrambled face. The activity in each task was compared with that in the control fixation (CF) task, in which they fixated on the centre of a display without visual stimuli. The DL task activated the occipital cortices and posterior fusiform gyri bilaterally. During the FD task, the activation extended anteriorly in the right fusiform gyrus and laterally to the right inferior temporal cortex. The FF task further activated the right temporal pole. To examine whether the activation due to faces was face-specific, we used a scene familiar/unfamiliar discrimination (SF) task, in which the subjects discriminated familiar scenes from unfamiliar ones. Our results suggest that (i) the occipital cortices and posterior fusiform gyri non-selectively respond to faces, scrambled faces and scenes, and are involved mainly in the extraction of physical features of complex visual images; (ii) the right inferior temporal/fusiform gyrus responds selectively to faces but not to non-face stimuli and is involved in the visual processing related to face perception, whereas the bilateral parahippocampal gyri and parieto-occipital junctions respond selectively to scenes and are involved in processing related to scene perception; and (iii) the right temporal pole is activated during the discrimination of familiar faces and scenes from unfamiliar ones, and is probably involved in the recognition of familiar objects.

Adult↗
PubMed2000

Wild type ApoA-II gene does not rescue senescence-accelerated mouse (SAMP1) from short life span and accelerated mortality.

Biochemical and genetic data suggest that the Apoa2c allele of the apolipoprotein A-II gene causes severe senile amyloidosis (AApoAII) in SAMP1, a mouse model for accelerated senescence. We analyzed the effects of replacement of Apoa2c in SAMP1 mice with non-amyloidogenic Apoa2b on amyloidosis, lipoprotein metabolism, and progression of senescence using a congenic strain, P1.R1-Apoa2b, which has the Apoa2b chromosome region of SAMR1 in the genome of SAMP1. Age-associated amyloid deposition was not observed, but plasma concentrations of apoA-II protein and HDL-cholesterol decreased with age in P1.R1-Apoa2b. P1.R1-Apoa2b showed lower scores of senescence than did SAMP1. However, the life span and mortality rate doubling time were similar in P1.R1-Apoa2b and SAMP1. These results suggest that replacement of Apoa2c with non-amyloidogenic Apoa2b does not rescue SAMP1 mice from a short life span and accelerated mortality.

Aging↗
PubMed2000

Combined effects of meropenem and aminoglycosides on Pseudomonas aeruginosa in vitro.

To investigate combinations of antibiotics against Pseudomonas aeruginosa, the in vitro effects of combinations of meropenem with each of three aminoglycosides, arbekacin, amikacin and netilmicin, were evaluated using an agar dilution chequerboard technique. The combinations of meropenem and aminoglycosides were effective against almost all P. aeruginosa strains tested, which included meropenem-resistant strains. Increased synergic effects were observed in combinations that included arbekacin or amikacin. None of the combinations had an antagonistic effect. Most of the synergic and additive effects were achieved at clinically relevant concentrations.

Aminoglycosides↗
PubMed2000

Stereospecific synthesis of alpha-anomeric pyrimidine nucleoside.

A facile stereospecific synthetic method for alpha-anomeric 2'-deoxypyrimidine nucleoside unit utilizing aminooxazoline derivative of ribofuranose was investigated. Thus, easily accessible riboaminooxazoline derivative prepared by ribose and cyanamid was allowed to react with ethyl alpha-bromoethylacrylate to give corresponding adduct. The adduct was cyclized by strong base such as potassium t-butokiside. The resulted 2,2'-cyclonucleoside was then treated with acetyl bromide followed by n-butyltin hydride to give alpha-anomeric 3',5'-di-O-acetylthymidine. 3',5'-Di-O-acety groups of the nucleoside were easily removed by the action of excess of triethyl amine in methanol. Essentially same procedure afforded corresponding 2'-deoxyuridine, which was further, converted to alpha-anomeric 2'-deoxycytidine.

Deoxycytidine↗
PubMed2000

beta(2)-adrenoceptor agonist suppresses renal tumour necrosis factor and enhances interleukin-6 gene expression induced by endotoxin.

BACKGROUND: beta(2)-Adrenoceptor activation regulates tumour necrosis factor (TNF)-alpha and interleukin-6 (IL-6) production in cultured renal cells. However, it remains uncertain whether, in vivo, the administration of beta(2)-adrenoceptor agonists regulate renal TNF-alpha and IL-6 mRNA following lipopolysaccharide (LPS) stimulation to cause endotoxaemia. This study was performed in order to evaluate the effect of beta(2)-adrenoceptor agonist on renal TNF-alpha and IL-6 production. METHODS: Four-week-old Wistar rats pre-treated with the beta(2)-adrenoceptor agonist terbutaline or formoterol, and/or the beta- and beta(2)-adrenoceptor antagonists (propanolol, ICI118,551), were injected with LPS (1 mg i.p.), and then 2, 4 or 6 h later, kidneys (cortex, medulla), spleen, thymus and plasma were collected to assay TNF-alpha and IL-6 mRNA levels and their respective protein release. RESULTS: Administration of beta(2)-adrenoceptor agonists suppressed TNF-alpha mRNA expression in the whole kidney, by 61% (P<0.05), as well as plasma, spleen and thymus TNF-alpha protein and mRNA expression 2 hours after injection of LPS. On the other hand, although IL-6 levels in plasma, spleen and thymus mRNA expression were suppressed significantly by administration of beta(2)-adrenoceptor agonists, the basal- and LPS-induced IL-6 mRNA levels in the whole kidney were increased 1.6- and 1.2-fold (P<0.05), respectively, by treatment with beta(2)-adrenoceptor agonists. beta(2)-Adrenoceptor agonist suppressed LPS-induced TNF-alpha mRNA expression by 35% (P<0.05) and stimulated LPS-induced IL-6 mRNA expression by 1.5-fold (P<0.05) in the medullary region of kidney. CONCLUSIONS: beta(2)-Adrenoceptor agonists down-regulate renal TNF-alpha mRNA expression following LPS-induced endotoxaemia. This effect was particularly apparent in the renal medulla. IL-6 mRNA expression in the renal medulla was up-regulated by the agonists whereas plasma, spleen and thymus IL-6 levels were completely inhibited by the agonist, which suggests the existence of tissue specific regulation of IL-6 production in the kidney by beta(2)-adrenoceptor activation.

Adrenergic beta-Agonists↗
PubMed2000

Genes encoding pseudo-response regulators: insight into His-to-Asp phosphorelay and circadian rhythm in Arabidopsis thaliana.

In the higher plant, Arabidopsis thaliana, results from recent intensive studies suggested that His-to-Asp phosphorelay mechanisms are involved presumably in propagation of environmental stimuli, such as phytohormones (e.g. ethylene and cytokinin). Here we identified and characterized a set of novel Arabidopsis genes whose products considerably resemble the authentic response regulators (ARR-series) of Arabidopsis in the sense that they have a phospho-accepting receiver-like domain. However, they should be discriminated from the classical ones in the strict sense that they lack the invariant phospho-accepting aspartate site. They were thus named APRRs (Arabidopsis pseudo-response regulators). Two such representatives, APRR1 and APRR2, were characterized extensively through cloning of the corresponding cDNAs, in terms of their structural designs, biochemical properties, subcellular localization in plant cells, and expression profiles at the transcriptional level. The result of in vitro phosphorylation experiment with the Arabidopsis AHP phosphotransmitter suggested that the pseudo-receivers have no ability to undergo phosphorylation. The result of transient expression assay with onion epidermal cells showed that the GFP-APRR1 fusion protein has an ability to enter into the nuclei. The C-terminal domain of APRR1, termed CONSTANS-motif, appears to be responsible for the nuclear-localization. The most intriguing result was that the accumulation of APRR1 transcript is subjected to a circadian rhythm. The APRR1 protein is identical to the one that was recently suggested to interact with the ABI3 (ABISCISIC ACID INSENSITIVE3) protein. These are discussed with special reference to the His-to-Asp phosphorelay signal transduction and circadian rhythm in Arabidopsis thaliana.

Amino Acid Sequence↗
PubMed2000

Distinct action of aranidipine and its active metabolite on renal arterioles, with special reference to renal protection.

Aranidipine, a newly developed calcium antagonist, possesses unique pharmacologic characteristics in that its metabolite (M-1) still has antihypertensive action. We examined the effects of both agents on renal microcirculation using the isolated perfused hydronephrotic rat kidney. During norepinephrine-induced constriction, the addition of aranidipine dilated both afferent and efferent arterioles in a dose-dependent manner; at 10(-6) M, 83 +/- 6% and 90 +/- 6% reversal, respectively. In contrast, its active metabolite exerted dilator action predominantly on the afferent arteriole (79 +/- 4% vs. 44 +/- 17% at 10(-6) M for afferent and efferent arterioles, respectively). We further examined the long-term (8 weeks) effect of these agents on the development of renal injury in salt-loaded subtotally nephrectomized spontaneously hypertensive rats. Both aranidipine and M-1 reduced blood pressure by a similar magnitude. The decreases in proteinuria were observed in the aranidipine-treated group at weeks 6, 8, and 10, whereas in the M-1 group, significant reduction was attained only at week 6. Histopathologic examination revealed that both treatments improved glomerular and arteriolar sclerosis. Glomerular sclerosis, however, was less pronounced in the aranidipine-treated group than in the M-1 group. In conclusion, aranidipine has dilator action on both arterioles, whereas M-1 caused predominant dilation of afferent arterioles. Such metabolic changes may constitute a determinant of efferent arteriolar action of the calcium antagonist.

Animals↗
PubMed2000

Characterization of Streptococcus pneumoniae strains isolated from systemic infections in children.

Twenty-three cases of systemic pneumococcal infection diagnosed from October 1988 to September 1998 were analyzed retrospectively in order to characterize the epidemiology of systemic pneumococcal infections. The clinical diagnosis of those cases were 8 pneumonia, 8 meningitis, 3 septicemia, 3 septic arthritis, and 1 peritonitis. The patients ranged in age from 6 months to 21 years old (mean +/- SD = 3 years, 6 months +/- 5 years, 2 months), and 61% of the patients were younger than 24 months. Resistance to penicillin G (PCG) was detected in 57% of all cases. Resistance to cefotaxime (CTX), imipenem (IPM), erythromycin (EM), and clindamycin (CLDM) was 33%, 9%, 70%, and 65%, respectively. Of the 13 isolates resistant to PCG, 2 were resistant to IPM, 11 to EM and 11 to CLDM. Serotyping was performed on 17 isolates. The identified serotypes were 19 (6 isolates), 6 (5 isolates), 23 (3 isolates), 14 (2 isolates), and 5 (1 isolate). Eleven isolates resistant to PCG were limited to serotypes 6, 19, or 23. One patient had a recurrent episode of bacteremic pneumonia 7 months after the first episode. Streptococcus pneumoniae isolates from both episodes were compared by serotyping and pulsed-field gel electrophoresis with restriction digestion, and were confirmed as the same strain.

Adolescent↗
PubMed2000

[A trial of amantadine for the treatment of influenza A infection in children].

We administered amantadine to 52 children for therapy and 3 children for prophylaxis of influenza A infection from January to March 1998. Among the 23 children in the therapy group with proven influenza A/H3N2 infection, 15 patients (60%) allayed fever within 3 days but 9 (40%) had persistent fever for more than 4 days after administration of amantadine. Seven of these nine patients (40%) received amantadine within 2 days after the onset of fever. Two of these nine had secondary bacterial infections. One child had insomnia as side effect. We concluded that administration of amantadine for therapy is safe and effective, if given to patients without secondary bacterial infections in the first 48 hours of the illness.

Adolescent↗
PubMed2000

[Epidemiological study on Staphylococcus epidermidis isolated from bloodstream and blood vessel catheter].

An epidemiological study on 35 strains of Staphylococcus epidermidis was conducted in Juntendo University Hospital between 1994 and 1996. The strains were isolated from blood and blood vessel catheters. Three epidemiological markers; PFGE type (pulsed-field gel electrophoresis using SmaI), biotype by STAPHYOGRAM and antibiotype (antibiotic resistant pattern) were used. There were 12 types in PFGE type, 6 types in biotype and 7 types in antibiotype. 1. The predominant types were PFGE type A (57.1%), biotype 1 (62.9%), and antibiotype I (resistant for oxacillin, ampicillin and gentamicin; 34.3%) in Juntendo University Hospital. 2. The strains with antibiotic V-VII (resistant for over 6 antibiotics) showed only PFGE type A and B. All strains with PFGE type B showed biotype 4-6 (negative nitrate reduction strain). 3. The strains having PFGE type A and B were isolated from various patient wards. The strains showing PFGE type A and antibiotype I were isolated from the pediatric ward. 4. There was no strain with PFGE type C or D in 1996. 5. Three patients in whom S. epidermidis was frequently isolated for a few months had the same types of PFGE type, biotype as well as antibiotype.

Blood↗