PubMed Health⌕ Search

Biomedical subjects

K Sakamoto

Publications and source records attributed to K Sakamoto.

At least 19 recordsLinked to original sources
PubMed2006

Mapping and characterization of FLC homologs and QTL analysis of flowering time in Brassica oleracea.

The FLC gene product is an inhibitor of flowering in Arabidopsis. FLC homologs in Brassica species are thought to control vernalization. We cloned four FLC homologs (BoFLCs) from Brassica oleracea. Three of these, BoFLC1, BoFLC3 and BoFLC5, have been previously characterized. The fourth novel sequence displayed 98% sequence homology to the previously identified gene BoFLC4, but also showed 91% homology to BrFLC2 from Brassica rapa. Phylogenetic analysis showed that this clone belongs to the FLC2 clade. Therefore, we designated this gene BoFLC2. Based on the segregation of RFLP, SRAP, CAPS, SSR and AFLP loci, a detailed linkage map of B. oleracea was constructed in the F(2) progeny obtained from a cross of B. oleracea cv. Green Comet (broccoli; non-vernalization type) and B. oleracea cv. Reiho (cabbage; vernalization type), which covered 540 cM, 9 major linkage groups. Six quantitative trait loci (QTL) controlling flowering time were detected. BoFLC1, BoFLC3 and BoFLC5 were not linked to the QTLs controlling flowering time. However, the largest QTL effect was located in the region where BoFLC2 was mapped. Genotyping of F(2 )plants at the BoFLC2 locus showed that most of the early flowering plants were homozygotes of BoFLC-GC, whereas most of the late- and non-flowering plants were homozygotes of BoFLC-Rei. The BoFLC2 homologs present in plants of the non-vernalization type were non-functional, due to a frameshift in exon 4. Moreover, duplications and deletions of BoFLC2 were detected in broccoli and a rapid cycling line, respectively. These results suggest that BoFLC2 contributes to the control of flowering time in B. oleracea.

Arabidopsis Proteins↗
PubMed2006

Homer1c interacts with Hippi and protects striatal neurons from apoptosis.

By the two hybrid screening of mouse brain cDNA library, we identified Hppi, a cell death-promoting protein, as a binding partner of postsynaptic scaffold protein Homer1c. Hippi interacted specifically with Homer1c but not with its homologue Homer2. It was reported that Hippi, when complexed with Hip1, induces the apoptosis in striatal neurons and may cause Huntington's disease. We found that this apoptotic effect of Hippi was specific to the striatum and was not observed in hippocampal neurons. Furthermore, the apoptotic effect of Hippi was prevented when Homer1c was co-expressed in cultured striatal neurons. The protective effect of Homer1c was diminished when Hippi binding domain was deleted. These results suggest that Homer1c may play an important role in the mechanisms of neuronal death in the striatum.

Adaptor Proteins, Signal Transducing↗
PubMed2006

The immunohistochemical expression of p21WAF1/Cip1 and Proliferating cell nuclear antigen in laryngeal squamous cell carcinomas.

The purpose of this study was to assess the significance of the expression of p21WAF1/Cip1 and proliferating cell nuclear antigen (PCNA) in human laryngeal squamous cell carcinomas. Forty-eight patients (25 supraglottic, 23 glottic) who had undergone operations between 1998 and 2003 were included in this study. The Envision immunohistochemistry method was utilized to stain these tissue specimens. The results showed that the immunostaining of p21WAF1/Cip1 do not show any correlation with differentiation, N stage, metastasis, survival, recurrence or the laryngeal site of involvement. A significant inverse correlation was detected between p21WAF1/Cip1 and the T stage. In contrast, the percentage of PCNA labelled cells showed a significant correlation with the T stage, but not with other clinicopathological parameters. There were differences in the expression of p21WAF1/Cip1 and PCNA between the supraglottic and the glottic carcinomas. In conclusion, our findings suggest that p21WAF1/Cip1 and PCNA may play an important role in the progression of carcinoma of the supraglottic larynx.

Adult↗
PubMed2006

Observation and control of transverse energy-transport barrier due to the formation of an energetic-electron layer with sheared ExB flow.

Off-axis electron-cyclotron heating in an axisymmetric barrier mirror produces a cylindrical layer with energetic electrons, which flow through the central cell and into the end region. The layer, producing a localized bumped ambipolar potential Phi(C), forms a strong shear of radial electric fields E(r) and peaked vorticity with the direction reversal of E(r)xB sheared flow near the Phi(C) peak. Intermittent vortexlike turbulent structures near the layer are suppressed in the central cell by this actively produced transverse energy-transport barrier; this results in T(e) and T(i) rises surrounded by the layer.

Journal Article↗
PubMed2006

Association of soluble CD40 ligand with carotid atherosclerosis in Japanese type 1 diabetic patients.

AIMS/HYPOTHESIS: It has recently been shown that the soluble form of CD40 ligand (sCD40L) interacts with CD40 on vascular cells, leading to a variety of proinflammatory responses, and that serum sCD40L levels can be a predictive marker of cardiovascular events. The aim of this study was to estimate sCD40L levels in type 1 diabetic patients to examine a possible association with carotid atherosclerosis. SUBJECTS AND METHODS: Human sCD40L levels in serum and intima-media thickness (IMT) of carotid artery were examined in 80 Japanese type 1 diabetic patients (27 men and 53 women, age 22.8+/-3.4 years (mean+/-SD), duration of diabetes 13.2+/-6.1 years) and 20 healthy age-matched non-diabetic individuals. RESULTS: Serum sCD40L levels were significantly (p=0.0185) higher in subjects with type 1 diabetes (2.10+/-1.33 ng/ml) compared with non-diabetic subjects (1.35+/-0.88 ng/ml). The greatest IMT (Max-IMT) and averaged IMT (Mean-IMT) were also significantly greater in patients with type 1 diabetes than in control subjects (0.73+/-0.14 vs 0.64+/-0.07 mm, p=0.0041, 0.63+/-0.09 vs 0.57+/-0.06 mm, p=0.0066, respectively). Levels of sCD40L were statistically significantly associated with Max-IMT (r=0.383, p<0.001) and Mean-IMT (r=0.275, p=0.0058). Furthermore, stepwise multivariate regression analyses demonstrated that sCD40L is a determinant of both Max- and Mean-IMT, independently of conventional risk factors. CONCLUSIONS/INTERPRETATION: It is suggested that increased levels of serum sCD40L are associated with accelerated atherosclerotic change observed in young patients with type 1 diabetes.

Adult↗
PubMed2006

Chain ordering of Stratum corneum lipids investigated by EPR slow-tumbling simulation.

We investigated the chain ordering of the lipid bilayer of Stratum corneum (SC) using an electron paramagnetic resonance (EPR) spin probe method in conjunction with slow-tumbling simulation. The ordering of SC lipids was evaluated by analysis of the signals of 5-doxylstearic acid (5-DSA) spin probe incorporated into the lamellar lipids. The result obtained with the conventional method of calculating the order parameter using hyperfine values was 0.80. The value of the order parameter obtained by spectral simulation was 0.73. It was found that the conventional method of calculating the chain ordering using hyperfine values could not differentiate subtle EPR spectral changes. However, EPR slow-tumbling simulation can differentiate such subtle spectral changes. Thus, the present EPR investigation suggests that simulation provides more detail about the structure of the lipid bilayer than the conventional method.

Computer Simulation↗
PubMed2006

Increased stress protein ORP150 autoantibody production in Type 1 diabetic patients.

AIMS: Various genetic and environmental stresses interfere with protein folding in the endoplasmic reticulum (ER), which leads to the induction of ER stress. It has recently been reported that ER stress is involved in the development of diabetes in diabetic animal models. The aim of this study is to estimate ER stress levels in Type 1 diabetic patients. METHODS: We recruited Type 1 diabetic patients undergoing periodic follow-up examinations (n = 91) and healthy non-diabetic individuals (n = 37), and measured their serum anti-oxygen-related protein (ORP)150 autoantibody levels. RESULTS: Anti-ORP150 autoantibody levels in Type 1 diabetic patients were significantly higher compared with those in healthy non-diabetic subjects. Furthermore, the serum autoantibody levels in Type 1 diabetic patients correlated with HbA(1c) (F > 3.0, P = 0.079), indicating that hyperglycaemia itself induces ER stress in diabetes. CONCLUSIONS: Anti-ORP150 autoantibody levels in Type 1 diabetic patients are higher compared with non-diabetic subjects, suggesting that ER stress is increased in Type 1 diabetes.

Adult↗
PubMed2006

A novel NADP+-dependent L-1-amino-2-propanol dehydrogenase from Rhodococcus erythropolis MAK154: a promising enzyme for the production of double chiral aminoalcohols.

AIM: A novel NADP(+)-dependent L-1-amino-2-propanol dehydrogenase was isolated from Rhodococcus erythropolis MAK154, and characterized. METHODS AND RESULTS: The enzyme was inducibly produced on cultivation with aminoalcohols such as 1-amino-2-propanol, 1-amino-2-butanol and 2-aminocyclohexanol. The enzyme catalyses the NADP(+)-dependent oxidation of several aminoalcohols, and also the NADPH-dependent asymmetric reduction of an aminoketone compound to a double chiral aminoalcohol, d-pseudoephedrine. Amino acid sequence analysis showed that the enzyme might belong to the short-chain dehydrogenase/reductase family. CONCLUSIONS: NADP(+)-dependent L-1-amino-2-propanol dehydrogenase isolated from R. erythropolis MAK154 reversibly catalysed dehydrogenation of aminoalcohols, and exhibited a unique sterospecifity for the reduction reaction. SIGNIFICANCE AND IMPACT OF THE STUDY: The enzyme is a promising catalyst for the production of double chiral compound, d-pseudoephedrine, from prochiral substrate.

Alcohol Dehydrogenase↗
PubMed2006

Iron chelators may help prevent photoaging.

For years, cosmetic ingredients for anti-aging treatments have attracted consumers. Skin aging is accelerated by reactive oxygen species (ROS), generated by exposure to solar ultraviolet radiation (UVR), in a process known as photoaging. Because cutaneous iron catalyses ROS generation, it is thought to play a key role in photoaging. Iron is essential to almost all forms of life. However, excess iron is potentially toxic as its catalytic activity induces the generation of ROS. Iron-catalysed ROS generation is involved in numerous pathological conditions, including cutaneous damage. When skin is directly exposed to UVR, cutaneous intracellular catalytic iron levels increase because of the release of iron from iron-binding proteins such as ferritin. Consequently, the subsequent ROS generation may overwhelm cutaneous defense systems such as the cellular iron sequestration and ROS scavenging capacity. The harmful role of excess cutaneous iron implies that there may be a potential for topical iron chelator treatments. We now consider cutaneous photodamage skin photoaging as the result of iron-catalysed ROS generation and discuss preventative strategies based on iron chelators.

Humans↗
PubMed2006

Prognosis and morphometrical features of non-bronchioloalveolar cell adenocarcinoma: an assessment of the non-alveolar replacing area and high grade atypical area.

AIM: It has become obvious that the prognosis of bronchioloalveolar cell carcinoma (BAC) in small peripheral adenocarcinoma of the lung is good, but most cases actually treated as pulmonary adenocarcinoma in hospitals tend to be non-bronchioloalveolar cell carcinoma (non-BAC). The prognoses of non-BAC are greatly varied. We studied the relationships between the morphometrical features and the prognoses of non-BAC. METHODS: In total, 69 cases of non-BAC measuring <or=20 mm in diameter across their greatest dimension were evaluated. We considered that the non-alveolar replacing area and the high grade atypical area were related to the prognosis, and therefore defined the ratio of both areas to the total area at the maximum face of the tumours as the non-alveolar replacing area ratio (NAAR) and the high grade atypical area ratio (HAAR), respectively. We thereafter analysed the relationships between both ratios and the prognosis. RESULTS: The NAAR and HAAR were significantly higher in the recurrent cases than in the recurrence free cases. We divided the non-BAC cases at the centre of both ratios into two groups, high and low. The 5 year survival rate of the high NAAR and high HAAR group was 48.3%, while that of the low NAAR and low HAAR group was 72.2%. The groups showing high rates for both ratios had significantly worse prognoses. A multivariate analysis indicated that the HAAR contributes most to the prognosis. CONCLUSIONS: These results suggest that the NAAR and HAAR are closely associated with the prognosis of non-BAC.

Adenocarcinoma↗
PubMed2006

Effects of endogenous and exogenous prostaglandin E2 on the proliferation and differentiation of a mouse cementoblast cell line (OCCM-30).

BACKGROUND: Cementum formation is considered to be a critical event for successful regeneration of periodontal tissues. Cementoblasts share many characteristics with osteoblasts. Prostaglandin E(2) (PGE(2)) is an important local factor in bone metabolism. Although the effects of PGE(2) on osteoblasts are well known, its effects on cementoblasts have not yet been established. We examined the effects of PGE(2) on proliferation and differentiation in a mouse cementoblast cell line, OCCM-30 cells. METHODS: OCCM-30 cells were treated with three concentrations of PGE(2) (10, 100, and 1,000 ng/ml). Cell number, alkaline phosphatase (ALP) activity, and expression for mineralization-related genes were determined. Osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa B (NF-kappaB) ligand (RANKL) expression were also examined by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). RESULTS: The addition of PGE(2) at the highest dose used in this study suppressed cell proliferation of OCCM-30 cells. The expression of mineralization-related marker mRNA, such as type 1 collagen, ALP, bone sialoprotein (BSP), and osteocalcin (OCN), was constitutively detected in OCCM-30 cells. PGE(2) dose dependently stimulated ALP activity and BSP-mRNA expression in OCCM-30 cells at day 3. Transcripts for OPG and RANKL and the protein level of OPG in culture media were upregulated with PGE(2) stimulation. CONCLUSION: These results demonstrate that PGE(2) suppressed cementoblast proliferation but stimulated ALP activity and the BSP-mRNA level, suggesting a role of PGE(2) in controlling cementoblast differentiation, and further indicate that PGE(2) modulates RANKL and OPG expression in cementoblasts; the increase of OPG secreted from cementoblasts with PGE(2) stimulation may be essential to protect the root surface from resorption.

Alkaline Phosphatase↗
PubMed2005

Preparation and characterization of spherical polymer packings from polybutadiene for size-exclusion chromatography.

Porous polymer spherical particles for column packings in nonaqueous size-exclusion chromatography (SEC) were prepared from 1,2-syndiotactic polybutadiene by suspension and evaporation method. The polymer microbeads obtained were crosslinked by radical reaction between 2-vinyl groups in polybutadiene with ultraviolet radiation, to render them insoluble. These microbeads have wider chromatographic separation width than polystyrene column packings. In addition, the polybutadiene microbeads did not show the excessive retention observed with commercial polystyrene columns for polycyclic aromatic compounds. Therefore, a close correlation between the elution volume and M, for polycyclic aromatic compounds was observed with polybutadiene microbeads columns.

Butadienes↗
PubMed2005

Preventive actions of a high dose of glucosamine on adjuvant arthritis in rats.

OBJECTIVE: Glucosamine, a naturally occurring amino monosaccharide has been used to treat or prevent osteoarthritis in humans. In this study, we evaluated the effect of glucosamine on rat adjuvant arthritis, a model of rheumatoid arthritis. MATERIALS AND METHODS: Adjuvant arthritis was induced in male Wistar rats by injection of Freund's complete adjuvant (FCA) into the right hind paw, and 300 mg/kg of glucosamine, an extra-dose compared with a regular dose for osteoarthritis patients (1.5 g/day, approximately 25 mg/kg), was orally administered once a day to the arthritic rats for 22 days. RESULTS: Glucosamine significantly suppressed the increase in arthritis score (p < 0.05) after day 10 of adjuvant injection, and inhibited the swelling of FCA-injected right and -uninjected left hind paws (p < 0.01) after day 18. In addition, histopathological examination of the arthritic joints revealed that glucosamine suppressed synovial hyperplasia, cartilage destruction and inflammatory cell infiltration. Furthermore, glucosamine reduced the production of nitric oxide and prostaglandin E(2) in plasma (p < 0.05). CONCLUSIONS: These observations suggest that glucosamine is able to suppress the progression of adjuvant arthritis in rats. Glucosamine may be expected as a novel anti-inflammatory agent for treatment of rheumatoid arthritis.

Animals↗
PubMed2005

Inhibitory action of glucosamine on platelet activation in guinea pigs.

OBJECTIVE: Glucosamine, a naturally occurring amino monosaccharide, has been used to treat or prevent osteoarthritis in humans. Recently, we have revealed that glucosamine inhibits platelet activation in vitro. However, the effect of in vivo administration of glucosamine has not yet been clarified. In this study, we administered glucosamine orally to guinea pigs and examined its effects on platelet functions. MATERIALS AND METHODS: Glucosamine hydrochloride solution (0.5%, 5 mg/ml) was administered orally to guinea pigs ad libitum for 22 days, and platelet rich plasma was collected to evaluate platelet functions in vitro. Guinea pigs received an average of 400 mg glucosamine/animal/day. RESULTS: Glucosamine-administration suppressed platelet aggregation in response to ADP by 51% (p < 0.01), but not platelet aggregation induced by collagen. Furthermore, glucosamine-administration inhibited the ADP-induced extracellular release of ATP and production of thromboxane A(2) by 91% and 96%, respectively (p < 0.001). In contrast, glucosamine did not affect the body-weights, platelet counts and bleeding time in guinea pigs after the administration. CONCLUSIONS: These observations suggest that glucosamine is likely to exert an inhibitory action on platelets in vivo by suppressing platelet aggregation, ATP release, and thromboxane A(2) production. Thus, glucosamine could be expected as a novel and safe anti-platelet agent.

Adenosine Diphosphate↗
PubMed2005

Possible involvement of urokinase-type plasminogen activator release from human peripheral blood lymphocytes in the pathophysiology of chronic allograft nephropathy.

BACKGROUND: Little is known of the fibrinolytic host immune mechanisms responsible for induction of chronic allograft nephropathy (CAN), defined as a loss in glomerular filtration rate (GFR) caused by tubular atrophy and interstitial fibrosis, often with fibrous intimal thickening in the small arteries. However, chronic rejection has been reported to be associated with decreased activity of the fibrinolytic system. In our previous study, [Deamino-Cys1, D-Arg8]-vasopressin (dDAVP) induced urokinase-type plasminogen activator (uPA) release from human peripheral T lymphocytes via arginine vasopressin (AVP) V2-receptor-mediated reaction enhanced by an AVP V1-receptor antagonist. Therefore, we examined the level of uPA released from peripheral T lymphocytes by AVP in transplant patients with CAN in comparison with control groups. PATIENTS AND METHODS: In this study, we evaluated in vitro uPA releasing activity of lymphocytes obtained from renal allograft patients with well-functioning grafts (n = 9), CAN (n = 5), or acute rejection episodes (n = 5) compared with lymphocytes from healthy volunteers with normal renal function (n = 12) or patients with renal insufficiency (n = 5). RESULTS: Lymphocytes prepared from patients with chronic allograft nephropathy showed a significantly lower increase in uPA release induced by the combination of the V1-receptor antagonist and dDAVP compared with those from the other groups. CONCLUSION: This finding suggested that a decrease in uPA release from human peripheral blood lymphocytes by AVP-related peptides may be potentially involved in the pathophysiology of CAN.

Adult↗
PubMed2005

Primary invasive micropapillary carcinoma of the colon.

AIMS: Invasive micropapillary carcinoma (IMPC) is associated with frequent lymph node metastasis and adverse clinical outcome. IMPC has been reported in breast, urinary bladder, ureter, lung and parotid gland but not in colon. We present the clinicopathological features of three cases of primary IMPC of the colon with a review of the literature. METHODS AND RESULTS: The patients (one man and two women) were 53, 67 and 68 years old, respectively. The size of the tumour ranged from 20 to 100 mm in diameter. Histologically, all cases were composed predominantly of papillary tumour cell clusters with spaces in a background of fine fibrocollagenous stroma. One of the tumours (case 1) was nearly completely composed of IMPC, but the other two were associated with foci of adenocarcinoma and concurrent mucinous carcinoma, respectively. MUC1 was positive in all cases, suggestive of reverse cell orientation which is responsible for its unique histological features. CONCLUSIONS: We report three cases of primary IMPC of the colon. Its clinical significance remains undetermined but the presence of this component may represent a poor prognostic factor.

Aged↗