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Kenji Nakajima

Publications and source records attributed to Kenji Nakajima.

At least 19 recordsLinked to original sources
PubMed2006

Microbleeds in Alzheimer disease are more related to cerebral amyloid angiopathy than cerebrovascular disease.

Cerebral amyloid angiopathy (CAA) is one of the cardinal pathological features in the vascular components of Alzheimer's disease (AD). CAA itself results in disrupted microvasculature, mainly in the cerebral cortex, eventually leading to a brain cortical or subcortical hemorrhage in a population of elderly people, but clinically overt brain hemorrhages are not so frequent in AD patients. Here we assessed 50 AD patients and 26 controls to detect latent brain hemorrhages with gradient-echo T(2)*-weighted images, a sensitive magnetic resonance imaging technique to detect hemosiderin components in the brain. Microbleeds, demarcated as low-intensity spots in T(2)*-weighted images, were detected in 16.7% of AD patients without cerebrovascular disease (CVD) and in 12.5% of those with CVD, while no microbleeding was detected in the control subjects. No significant difference was observed between the microbleed-positive group and the microbleed-negative counterpart in their clinical background, such as hypertension, the use of antiplatelet drugs and smoking. In addition, white matter high intensities in the T(2)-weighted image were significantly more confluent in the microbleed-positive AD group than its negative counterpart. In conclusion, our evaluation of AD brains revealed that latent microbleeds in AD patients are more frequent than in normal controls. Microbleeds not being related to common hemorrhagic risk factors, but being significantly related to white matter pathologies suggested that microbleeds in AD may be associated with CAA, but not with hypertension or CVD.

Aged↗
PubMed2006

Hyperhomocysteinemia can be ameliorated by dimethylsulfoniopropionate in place of folic acid in mice.

Acute homocysteinemia mice were prepared by forcibly oral administration of homocysteine (4 mM, 2 mL). The amounts of plasma homocysteine were estimated by a fluorescence method with HPLC. Folic acid (0.6 mM, 2 mL), DMSP, or betaine (20 mM, 2 mL each) was intraperitoneally administrated into the mice suffered from the acute homocysteinemia on the 20th, 40th or 60th min after the oral supplementation of homocysteine, then amounts of plasma homocysteine were determined by the HPLC method 40 min after each addition, respectively. The results indicated that the intraperitoneal addition of folic acid or DMSP in this order of the 40th, 60th and 20th min after the oral supplementation of homocysteine significantly reduce the quantities of plasma homocysteine, but betaine exerted the fairly lesser effects. The amounts of homocysteine without any additive linearly and rapidly appeared to increase up to 60 min, at which those were about 8-12 fold the normal levels of homocysteine, and thereafter decreased in these experiments. Accordingly, folic acid which is known to effectively improve homocysteinemia was proven to be completely replaced by DMSP under the experimental conditions.

Animals↗
PubMed2006

Ameliorating effect of dimethylsulfoniopropionate on the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease of mice.

The effect of dimethylsulfoniopropionate (DMSP) on the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease (PD) of mice was examined for 5 d. The distilled water (the control group) and the DMSP solution at 5 x 10(-4) M (the DMSP group) were supplemented ad libitum to six mice each in two groups for 2 wk. An appropriate amount of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) solution (20 mg/kg body wt) was then intraperitoneally injected into all the test mice once a day initially for 3 d, which definitely made the control mice similar to the PD-model mice. The moving ability (running power) of the mice in both groups was measured using an automatic Wheel Running Instrument. The immobility duration of the upside-down mice in both groups was estimated by a newly developed polygraph (RMP-6008M, Nihon Koden Co., Ltd., Japan). The results indicated that the mice in the DMSP group showed a stronger moving ability and a shorter immobility duration compared to the mice in the control group during the experimental period. Furthermore, the amounts of catecholamines (dopamine and norepinephrine) in the brains except for the cerebellums of all the test mice were estimated 2 d after the last MPTP injection, which demonstrated that the brains of the mice in the DMSP group accumulate larger amounts of catecholamines, especially dopamine, than them in the control group. Accordingly, the administration of low concentrations of DMSP proved to prevent and/or ameliorate the decreased mobility and the typical immobility (Akinesia) of the MPTP-induced PD-model mice probably due to increased amounts of dopamine in the brains of the DMSP group mice.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2005

Discrepancy between clinical and pathological diagnoses of CBD and PSP.

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are often clinically confused with each other. Moreover, the discrepancy between clinical and pathological diagnoses of CBD and PSP are still controversial. We report here two atypical cases of PSP and CBD. A 73-year old woman was admitted with right hand rigidity, limb kinetic apraxia and cortical sensory loss. Brain atrophy, hypoperfusion and hypometabolism predominantly in the left frontoparietal lobes indicated CBD clinically. Pathological studies revealed neuronal loss and spongy change without ballooned neurons (BN) in the cerebral cortex. Modified Gallyas-Braak (G-B) staining revealed neurofibrillary tangles (NFTs) and tufted astrocytes, indicating pathological diagnosis of PSP. A 75-year-old man admitted with vertical gaze palsy, neck dystonia, parkinsonism and dementia. Atrophy of the frontal lobes and tegmentum of the midbrain and symmetrical frontal hypoperfusion in SPECT indicated PSP. However, neuronal loss and BN in the frontal lobes and clusters of astrocytic plaques indicated CBD pathologically. The G-B staining was useful for differentiating between CBD and PSP, but our atypical cases bring up a new issue about differential diagnosis of CBD and PSP.

Aged↗
PubMed2005

Oceanobacillus oncorhynchi sp. nov., a halotolerant obligate alkaliphile isolated from the skin of a rainbow trout (Oncorhynchus mykiss), and emended description of the genus Oceanobacillus.

A halotolerant, obligately alkaliphilic bacterium, R-2(T), was isolated from the skin of a rainbow trout (Oncorhynchus mykiss), a freshwater fish. The strain is Gram-positive, ferments several carbohydrates, is rod-shaped and motile by peritrichous flagella and produces ellipsoidal spores. The isolate grows at pH 9-10 but not at pH 7-8. This micro-organism grows in 0-22% (w/v) NaCl at pH 10. Its major cellular fatty acids are iso-C(15:0), anteiso-C(15:0) and anteiso-C(17:0), the major isoprenoid quinone is MK-7 and the DNA G+C content is 38.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicates that strain R-2(T) is a member of the genus Oceanobacillus. DNA-DNA hybridization reveals low relatedness between the isolate and Oceanobacillus iheyensis (21.0%). On the basis of phenotypic characteristics, phylogenetic data and DNA-DNA relatedness data, the isolate should be designated as a novel species, for which the name Oceanobacillus oncorhynchi sp. nov. is proposed. The type strain is R-2(T) (=JCM 12661(T)=NCIMB 14022(T)).

Animals↗
PubMed2005

Alkalibacterium iburiense sp. nov., an obligate alkaliphile that reduces an indigo dye.

Three indigo-reducing obligately alkaliphilic strains, M3(T), 41A and 41C, were isolated. The isolates grew at pH 9-12, but not at pH 7-8. They were Gram-positive, facultatively anaerobic, straight rod-shaped strains with peritrichous flagella. The isolates grew in 0-14% (w/v) NaCl, with optimum growth at 3-13%. They grew at temperatures between 10 and 45 degrees C, with optimum growth at around 30-37 degrees C. They did not hydrolyse starch or gelatin. DL-lactate was the major end-product from D-glucose. No quinones could be detected. The peptidoglycan type was A4beta, Orn-d-Asp. The major cellular fatty acids were C(16:0), C(16:1)7c and C(18:1)9c. The DNA G+C content was 42.6-43.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequence data indicated that the isolates belong to the genus Alkalibacterium. DNA-DNA hybridization revealed low similarity (less than 16%) of the isolates with respect to the two closest phylogenetically related strains, Alkalibacterium olivapovliticus and Alkalibacterium psychrotolerans. On the basis of phenotypic and chemotaxonomic characteristics, phylogenetic data and DNA-DNA relatedness, the isolates merit classification as a novel species of the genus Alkalibacterium, for which the name Alkalibacterium iburiense is proposed. The type strain is M3(T) (=JCM 12662(T)=NCIMB 14024(T)).

Bacterial Typing Techniques↗
PubMed2005

Bacillus oshimensis sp. nov., a moderately halophilic, non-motile alkaliphile.

A halophilic and halotolerant, facultatively alkaliphilic strain, K11(T), was isolated from soil obtained from Oshyamanbe, Oshima, Hokkaido, Japan. The isolate grew at pH 7-10. It was non-motile, Gram-positive and aerobic. Cells comprised straight rods and produced ellipsoidal spores. The isolate grew in 0-20 % NaCl, with optimum growth at 7 % NaCl, and hydrolysed casein, gelatin, starch, DNA and Tweens 20, 40, 60 and 80. The major isoprenoid quinone was menaquinone-7, and the cellular fatty acid profile consisted of significant amounts of C(15) branched-chain acids, iso C(15 : 0) and anteiso C(15 : 0). Phylogenetic analysis based on 16S rRNA gene sequencing indicated that strain K11(T) was a member of group 6 [Nielsen et al., FEMS Microbiol Lett 117 (1994), 61-66] (alkaliphiles) of the genus Bacillus. DNA-DNA hybridization revealed a low relatedness (14 %) of the isolate to its closest phylogenetic neighbour, Bacillus clausii. On the basis of phenotypic and chemotaxonomic characteristics, phylogenetic data and DNA-DNA relatedness data, it was concluded that K11(T) (=JCM 12663(T)=NCIMB 14023(T)) merits classification as the type strain of a novel species, for which the name Bacillus oshimensis sp. nov. is proposed.

Bacillus↗
PubMed2005

Regulatory mechanisms of 6,7-dimethyl-8-ribityllumazine formation in resting cells of a riboflavin-adenine-deficient mutant of Bacillus subtilis.

The regulatory mechanisms of riboflavin biosynthesis in the resting cells of a riboflavin-adenine-deficient mutant of Bacillus subtilis were examined. The growth and pH of the medium remained unchanged in spite of the administration of 0-200 microg/mL riboflavin to the medium during incubation of the resting cells for 17 h. However, the formation of 6,7-dimethyl-8-ribityllumazine (DMRL) and flavin adenine dinucleotide (FAD) was restricted and augmented and then reached its plateau, showing an inverse relation in the addition of riboflavin up to 50 microg/mL to the medium and a parallel relation in the supplementation of riboflavin up to 200 microg/mL to the medium. In the experiments, the amount of flavin mononucleotide (FMN) was negligible and riboflavin was not detected in the resting cells. The results indicated that not the repression of related enzymes but negative feedback inhibition by FAD, but not that by riboflavin or FMN, is operative in the biosynthetic pathway of riboflavin in the riboflavin adenine double-less mutant of Bacillus subtilis.

Adenine↗
PubMed2005

Neuro-Behçet disease mimicking brain tumor.

Neuro-Behcet disease is one of the clinical forms of Behcet disease. We report a case of neuro-Behcet disease mimicked a brain tumor. This case was initially considered as a brain tumor from mass lesion with edema at left basal ganglia on radiologic images. The lesion, however, was not neoplasia by pathologic diagnosis. By using steroid therapy, the size had been markedly shrunken on the follow-up images. The clinical symptoms were also improved.

Adult↗
PubMed2004

Anoxybacillus voinovskiensis sp. nov., a moderately thermophilic bacterium from a hot spring in Kamchatka.

A novel moderately thermophilic bacterium, strain TH13T, was isolated from a hot spring in Kamchatka. It was found to be a Gram-positive, facultative aerobe; the straight, non-motile rods grew at 30-64 degrees C (optimum 54 degrees C). The isolate was positive for catalase and oxidase tests and reduced nitrate to nitrite, but was negative for H2S production and growth in more than 3% NaCl (w/v). The isolate grew at pH 7-8, but not at pH values higher than 9. The DNA G+C content was 43.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that strain TH13T was a member of the genus Anoxybacillus. DNA-DNA hybridization revealed a low relatedness (less than 30.2%) between the isolate and its close phylogenetic neighbours Anoxybacillus pushchinoensis and Anoxybacillus flavithermus. On the basis of phenotypic characteristics, phylogenetic data and DNA-DNA hybridization data, it was concluded that the isolate merited classification as a novel species, for which the name Anoxybacillus voinovskiensis sp. nov. is proposed. The type strain of this species is TH13T (=NCIMB 13956T=JCM 12111T).

Aerobiosis↗
PubMed2004

Bacillus asahii sp. nov., a novel bacterium isolated from soil with the ability to deodorize the bad smell generated from short-chain fatty acids.

In a screening campaign to isolate strains with the ability to remove the bad smell associated with animal faeces, strain MA001(T) was isolated from a soil sample obtained from Shizuoka prefecture, Japan. The isolate grew at pH 6-9 but not at pH 10. Cells were Gram-positive, straight rods with peritrichous flagella and produced ellipsoidal spores. The isolate was positive for catalase and oxidase tests but negative for indole production, deamination of phenylalanine and H(2)S production. The isolate did not produce acid from any carbohydrates tested and could not grow in more than 2 % NaCl. The DNA G+C content was 39.4 mol%. The cellular fatty acids profile consisted of significant amount of C(15) branched-chain fatty acids, iso-C(15 : 0) and anteiso-C(15 : 0). Phylogenetic analysis based on 16S rRNA gene sequencing indicated that strain MA001(T) was closely related to Bacillus simplex and Bacillus psychrosaccharolyticus. DNA-DNA hybridization revealed a low relatedness of the isolate to several phylogenetically close neighbours (less than 9 %). On the basis of the phenotypic characteristics observed, phylogenetic data based on 16S rRNA gene sequencing and DNA-DNA relatedness data, it is concluded that the isolate should be classified as representing a novel species, for which the name Bacillus asahii is proposed. The type strain is MA001(T) (=JCM 12112(T)=NCIMB 13969(T)).

Amino Acid Oxidoreductases↗
PubMed2004

Alkalibacterium psychrotolerans sp. nov., a psychrotolerant obligate alkaliphile that reduces an indigo dye.

A psychrotolerant, obligately alkaliphilic bacterium, IDR2-2(T), which is able to reduce indigo dye was isolated from a fermented polygonum indigo (Polygonum tinctorium Lour.) produced in Date, Hokkaido, using a traditional Japanese method. The isolate grew at pH 9-12 but not at pH 7-8. It was a Gram-positive, facultatively anaerobic, straight rod-shaped bacterium with peritrichous flagella. The isolate grew in 0-17 % (w/v) NaCl but not at NaCl concentrations higher than 18 % (w/v). Its major cellular fatty acids were C(14 : 0), C(16 : 0), C(16 : 1)9c and C(18 : 1)9c, and its DNA G+C content was 40.6 mol%. dl-lactic acid was the major end-product from d-glucose. No quinones could be detected. The peptidoglycan type was A4beta, Orn-d-Glu. A phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain IDR2-2(T) is a member of the genus Alkalibacterium. DNA-DNA hybridization revealed low relatedness (less than 25 %) between the isolate and two phylogenetically related strains, Alkalibacterium olivapovliticus and Marinilactibacillus psychrotolerans. On the basis of phenotypic characteristics, phylogenetic data and DNA-DNA relatedness data, the isolate merits classification as a novel species, for which the name Alkalibacterium psychrotolerans sp. nov. is proposed. The type strain is IDR2-2(T) (=JCM 12281(T)=NCIMB 13981(T)).

Anaerobiosis↗
PubMed2004

Enzymatic studies of riboflavin oversynthesis in Eremothecium ashbyii.

Mechanisms of riboflavin oversynthesis in a high flavinogenic mold, Eremothecium ashbyii, were examined in relation to growth, riboflavin formation and related synthases, and medium pH with increasing culture periods. Growth reached maximum at 1 d and then decreased, riboflavin formation proceeded rapidly up to 5 d and approached almost a plateau region. The medium pH reached minimum at 1 d and thereafter fairly rapidly increased until 3 d, then gradually increased to 7 d after cultivation. The crude enzyme solution from the mycelia at specified culture periods was run through a column of Sephadex G-200, indicating two riboflavin synthase activities on the chromatogram. The fluctuation of the growth and the specific activities of the two enzymes were examined with increasing culture periods, which showed that the heavy enzyme may be a constitutive one and that the light enzyme may be concerned with the oversynthesis of riboflavin in E. ashbyii. The heavy enzyme was then purified by 49-fold after dialysis of the ammonium sulfate precipitate by a series of column chromatographies with Sephadex G-200, hydroxyapatite, DEAE-Sepharose A-50 and DEAE-cellulose. The purified enzyme which was treated with weak alkaline solution was broken into the light enzyme, showing two bands on an acrylamide disc gel electrophoresis. The relation of the heavy and the light enzymes to the oversynthesis of riboflavin in E. ashbyii was discussed.

Electrophoresis, Disc↗
PubMed2004

Direct effects of high concentrations of dimethylsulfoniopropionate, vitamin E and ferulic acid on the senility of aged scenescene-accelerated mouse (SAMP8).

The effects of high concentrations of dimethylsulfoniopropionate (DMSP), vitamin E and ferulic acid solutions on the aging of male and female scenescene-accelerated mouse (SAMP8) at the age of 50 wk were examined by direct supplementation to their stomachs twice a week for 28-30 d. The addition of 1 mL of DMSP, vitamin E and ferulic acid solutions (21% each) to the male and female mice in each group in this order rather elevated their growth and significantly suppressed their total grading score and loss of learning and memory with increasing rearing times for the short experimental period. However, there were no significant differences found between the male and female mice during the experimental period. The antioxidant and hormonal actions for the effects of the test compounds on the aged SAMP8 were possibly considered.

Aging↗
PubMed2004

Effects of riboflavin on 6,7-dimethyl-8-ribityllumazine formation in growing cells of a riboflavin-adenine-deficient mutant, Bacillus subtilis.

The effects of riboflavin on the formation of 6,7-dimethyl-8-ribityllumazine (DMRL) were examined using the growing cells of a riboflavin, adenine deficient-mutant, Bacillus subtilis. The administration of low concentrations (50-500 ng/mL) of riboflavin to the basal medium significantly inhibited the formation of DMRL without any change in growth. Especially, the supplementation of more than 250 ng/mL riboflavin completely restricted the formation of DMRL under the experimental conditions. The results clearly indicate that a rigid negative feedback inhibition is operative for the biosynthetic pathway of riboflavin in B. subtilis.

Adenine↗
PubMed2003

A case of lymphomatoid granulomatosis/angiocentric immunoproliferative lesion with long clinical course and diffuse brain involvement.

Lymphomatoid granulomatosis (LYG)/angiocentric immunoproliferative lesions (AIL) consist of angiocentric and angiodestructive lymphoreticular proliferation predominantly involving the lungs and other extranodal sites, such as the central nervous system (CNS). This clinical entity is considered as a B cell process related to Epstein-Barr virus (EBV) infection and EBV positive diffuse large B-cell lymphoma. The CNS is involved in 20% of cases of LYG, but initial involvement is rare. In cases without pulmonary symptoms, diagnosis may be difficult. We report a rare case involving initial progression of CNS symptoms followed by a pulmonary abnormality.A 14-year-old girl suffered from high fever, ataxic gait and paraparesis. MRI revealed diffuse T2 high signals with multiple gadolinium enhancements in the cerebellum, brain stem and cerebral white matter. Her symptoms briefly improved after steroid therapy, but ataxia gradually progressed. Dyspnea due to pulmonary interstitial involvement appeared when she was 18 years old. Steroid therapy proved effective for respiratory symptoms. At 20 years old she suffered from disseminated intravascular coagulopathy (DIC) and hemophagocytic syndrome (HPS) with respiratory symptoms and repeated seizures. Her symptoms improved after the administration of cyclophosphamide. Mild hemiparesis and gait disturbance appeared when she was 22 years old. MRI revealed new lesions at the basal ganglia and subcortical white matter, brain atrophy and diffuse T2 high intensity of cerebral white matter. Cyclophosphamide was effective and there has been no recurrence of symptoms in the last 5 years. We reviewed the non-tumorous LYG/AIL involving the CNS, and discussed the clinical features, MRI imaging and diagnosis of the LYG/AIL.

Adolescent↗