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C Nakamura

Publications and source records attributed to C Nakamura.

At least 19 recordsLinked to original sources
PubMed2005

RU 58841-myristate--prodrug development for topical treatment of acne and androgenetic alopecia.

Acne and androgenetic alopecia are linked to androgen effects and therefore should improve following topical application of antiandrogens. We present a new antiandrogen prodrug, RU 58841-myristate (RUM) for topical therapy. Almost devoid of affinity to the androgen receptor, as derived from investigations in the mouse fibroblast cell line 29 +/GR +, RUM is rapidly metabolised to the potent antiandrogen RU 58841 by cultured human foreskin fibroblasts and keratinocytes, male occipital scalp skin dermal papilla cells, and by cells of the sebaceous gland cell line SZ95. In order to improve a specific targeting of the hair follicle, RUM was loaded on solid lipid nanoparticles (SLN), which are already known to support dermal targeting effects. Physically stable RUM loaded SLN were produced by hot homogenization. Penetration/permeation studies carried out using the Franz diffusion cell proved only negligible permeation of reconstructed epidermis and excised porcine skin within 6 h, implying a more topical action of the drug. Targeting to the hair follicle using SLN was visualised by fluorescence microscopy, following the application of Nile Red labelled SLN to human scalp skin. Transmission electron microscopy (TEM) allowed to detect intact silver labelled SLN in porcine hair follicles of preparations applied to the skin for 24 h. RUM loaded SLN should be considered for topical antiandrogen therapy of acne and androgenetic alopecia.

Acne Vulgaris↗
PubMed2004

Genetic diversity and phylogeny of Japanese sake-brewing rice as revealed by AFLP and nuclear and chloroplast SSR markers.

Japanese rice ( Oryza sativa L.) cultivars that are strictly used for the brewing of sake (Japanese rice wine) represent a unique and traditional group. These cultivars are characterized by common traits such as large grain size with low protein content and a large, central white-core structure. To understand the genetic diversity and phylogenetic characteristics of sake-brewing rice, we performed amplified fragment length polymorphism and simple sequence repeat analyses, using 95 cultivars of local and modern sake-brewing rice together with 76 cultivars of local and modern cooking rice. Our analysis of both nuclear and chloroplast genome polymorphisms showed that the genetic diversity in sake-brewing rice cultivars was much smaller than the diversity found in cooking rice cultivars. Interestingly, the genetic diversity within the modern sake-brewing cultivars was about twofold higher than the diversity within the local sake-brewing cultivars, which was in contrast to the cooking cultivars. This is most likely due to introgression of the modern cooking cultivars into the modern sake-brewing cultivars through breeding practices. Cluster analysis and chloroplast haplotype analysis suggested that the local sake-brewing cultivars originated monophyletically in the western regions of Japan. Analysis of variance tests showed that several markers were significantly associated with sake-brewing traits, particularly with the large white-core structure.

Analysis of Variance↗
PubMed2004

Glucocorticoid entrapment into lipid carriers--characterisation by parelectric spectroscopy and influence on dermal uptake.

Topical glucocorticoids such as betamethasone 17-valerate (BMV) and prednicarbate (PC) are an important therapeutic option in atopic eczema. To reduce the risk of dermal atrophy, we aimed at BMV incorporation into solid lipid nanoparticles (SLN) for epidermal targeting using various lipids and emulsifiers corresponding to previous work on PC. Cutaneous absorption into excised human skin was compared to the one with a cream. While Compritol-based particles increased BMV uptake about fourfold we failed, however, to obtain epidermal targeting. To obtain insight into the location of active substance relative to the carrier, we used the recently optimised method of parelectric spectroscopy (PS). In fact, we were able to study electric dipole movements in the broad field of a frequency span from 0.1 to 100 MHz demonstrating that glucocorticoids are attached to the particle surface but are not incorporated into the lipid matrix. With BMV, the loading capacity of the particle surface lies clearly below the usual concentration of 0.1% which is not the case with PC. An adequate association of drug and carrier is essential for epidermal targeting. Parelectric spectroscopy provides insight into the interaction between drug and lipidic carrier.

Adult↗
PubMed2004

[Stenting for postoperative airway stenosis due to traumatic tracheobronchial rupture].

A 43-year-old man underwent repair for the broken trachea, left main bronchus and right main brouchus due to trauma. Twenty-seven months after the initial surgery, he developed dyspnea and required ventilatory support. Computed tomography showed severe stenosis of the left main bronchus, tracheomalasia and bronchomalasia of right main bronchus. A self-expandable metallic stent (SEMS) was placed in the bilateral main bronchus and T-tube in the trachea. SEMS developed granulatory and cicatricial stenosis of the airway, which caused severe dyspnea. Replacement of SEMS with Dumon stents was successfully done and dyspnea was disappeared. A silicon stent should be used for treating postreconstructive airway stenosis including tracheobronchomalasia.

Bronchi↗
PubMed2003

Cold-specific and light-stimulated expression of a wheat (Triticum aestivum L.) Cor gene Wcor15 encoding a chloroplast-targeted protein.

Wcor15, a member of the wheat cold-responsive (Cor) gene family, has been isolated and characterized. The deduced polypeptide WCOR15 (MW=14.7 kDa) showed high homology to the previously identified wheat and barley COR proteins. Southern blot analysis using diploid, tetraploid and hexaploid wheat and diploid Aegilops species showed that the wheat and related wild genomes possessed multiple copies of Wcor15 homologues. Five copies were assigned to the homologous group 2 chromosomes by nulli-tetrasomic analysis. Northern blot analysis showed that expression of Wcor15 was specifically induced by low-temperature. Homologous transcripts accumulated in leaves, and light markedly increased their steady-state levels. Bombardment-mediated transient expression analysis of a chimeric CaMV 35S::Wcor15-GFP construct showed protein-targeting to epidermal guard cell chloroplasts in excised spiderwort leaves. A promoter of Wcor15 contained at least three CRT/DRE-like sequence motifs found in Arabidopsis Cor genes and induced the reporter GUS gene expression in leaves of transgenic tobacco plants under low-temperature and light conditions. These results suggest that the functional Cor gene system involving the CRT/DRE cis-element is conserved in both monocotyledonous and dicotyledonous plants.

Amino Acid Sequence↗
PubMed2002

A transcriptionally active maize MuDR-like transposable element in rice and its relatives.

Two Mu-like transposable elements were cloned from a rice genomic library using a partial cDNA clone that exhibits high homology to the mudrA gene of the maize element MuDR. Database searches led to the identification of six other sequences that carried highly homologous terminal inverted repeats (TIRs). All the rice elements possessed approximately 200-bp TIRs, and four were flanked by 9-bp target-site duplications (TSDs). The longer of the two cloned elements, OsMu4-2, could potentially encode a protein colinear with a MURA-like transposase, but it had stop codons in the coding region indicating that it is a pseudogene. All the other elements had large internal deletions. Direct dinucleotide repeats were found in two elements at positions flanking the deleted regions, suggesting that the deletions arose via the interrupted-gap-repair mechanism. Sequences related to empty sites of insertion were found in OsMu4-2 and one of the elements identified in the databases. These results provide evidence that the rice OsMu element was active and transposed in the past. Analysis of OsMu4-2 cDNAs revealed two types of transcripts produced by alternative splicing. Genomic Southern analysis suggested that OsMu4-2 was conserved in rice species with the A genome, but a deleted version was unique to japonica subspecies. Some wild rice species harbored paralogous copies of the OsMu element.

Amino Acid Sequence↗
PubMed2002

Expression of glucocorticoid receptor and 11beta hydroxysteroid dehydrogenase in a case of pulmonary epithelioid haemangioendothelioma.

This report describes a case of pulmonary epithelioid haemangioendothelioma in which the tumour cells expressed the glucocorticoid receptor and 11beta-hydroxysteroid dehydrogenase. The patient, a 15 year old girl, who had no other complaints or past illnesses, was found to have an abnormal shadow on a chest roentgenogram obtained at a school medical examination. Multiple nodular shadows in the bilateral lungs were also confirmed by computerised axial tomography scan. A diagnosis of pulmonary epithelioid haemangioendothelioma was made on the basis of lung biopsy specimens. The tumour cells were immunohistochemically positive for factor VIII related antigen, CD31, and CD34, but not surfactant apoprotein A. In addition, almost all of the tumour cells showed simultaneous expression of the glucocorticoid receptor and 11beta hydroxysteroid dehydrogenase, suggesting that steroid treatment would be effective.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2001

Phospholipase A(2)-catalyzed membrane leakage studied by immobilized liposome chromatography with online fluorescent detection.

Unilamellar liposomes composed of phosphatidylcholine with an entrapped self-quenching fluorescent dye, calcein, were immobilized in chromatographic gel beads by avidin-biotin binding. Bee venom phospholipase A(2) (PLA(2)) was applied in a small amount onto the immobilized liposome column. The release of calcein from the immobilized liposomes resulting from the catalyzed hydrolysis of the phospholipids was detected online by immobilized liposome chromatography (ILC) using a flow fluorescent detector. The PLA(2)-catalyzed membrane leakage of the immobilized liposomes as studied with ILC was found to be affected by the gel pore size used for immobilization, by liposome size, and as expected by the concentration of calcium, but was unaffected by the flow rate of ILC. The largest PLA(2)-induced calcein release from the liposome column was detected on large unilamellar liposomes immobilized on TSK G6000PW or Sephacryl S-1000 gel in the presence of 1 mM Ca(2+) in the aqueous mobile phase. Comparison with the PLA(2)-catalyzed membrane leakage in free liposome suspensions, we conclude that the fluorescent leakage from liposomes hydrolyzed by PLA(2) can be rapidly and sensitively detected by ILC runs using large amount of immobilized liposomes with entrapped fluorescent dye.

Animals↗
PubMed2001

High-performance liquid chromatographic assay for the simultaneous determination of lansoprazole enantiomers and metabolites in human liver microsomes.

In this study, a simple, sensitive and enantioselective HPLC method was developed for the simultaneous determination of lansoprazole enantiomers: a proton pump inhibitor, and its major metabolites: 5-hydroxylansoprazole and lansoprazole sulfone in human liver microsomes. After extraction from the microsomal incubation mixture with a diethyl etherdichloromethane (7:3, v/v) mixture, analytes were measured by reversed-phase HPLC on a Chiralcel OD-R column. Detection was made using an ultraviolet absorbance detector set at a wavelength of 285 nm. The mobile phase consisted of a methanol-water (75:25, v/v) mixture. At a flow-rate of 0.5 ml/min, the total run time was 35 min. The limit of quantification for both lansoprazole enantiomers was 0.25 microM and for the metabolites 0.13 microM. The method is suitable for the analysis of lansoprazole enantiomers and its metabolites from human microsomal liver incubations.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

Avidin-biotin-immobilized liposome column for chromatographic fluorescence on-line analysis of solute-membrane interactions.

Unilamellar liposomes with entrapped fluorescent dye calcein were stably immobilized in gel beads by avidin-biotin-binding. The immobilized liposomes remained extremely stable upon storage and chromatographic runs. The immobilized calcein-entrapped liposomes were utilized for fluorescent analysis of solute-membrane interactions, which in some cases are too weak to be detected by chromatographic retardation. A liposome column was used as a sensitive probe to detect the interactions of membranes with pharmaceutical drugs, peptides and proteins. Retardation of the solutes was monitored using a UV detector. Perturbation of the membranes, reflected as leakage of the entrapped calcein by some of the solutes, can thus be detected on-line using a flow-fluorescent detector. For the amphiphilic drugs or synthetic peptides, perturbation of membranes became more pronounced when the retardation (hydrophobicity) of the molecules increased. On the other hand, in the case of positively-charged peptides, polylysine, or partially denatured bovine carbonic anhydrase, significant dye leakage from the liposomes was observed although the retardation was hardly to be measured. Weak protein-membrane interactions can thus be assumed from the large leakage of calcein from the liposomes. This provides additional useful information for solute-membrane interactions, as perturbation of the membranes was also indicated by avidin-biotin-immobilized liposome chromatography (ILC).

Avidin↗
PubMed2001

Role of CYP3A4 and CYP2C19 in the stereoselective metabolism of lansoprazole by human liver microsomes.

OBJECTIVE: The aim of this investigation was to clarify the stereoselective properties in lansoprazole metabolism by monitoring the metabolic consumption for each enantiomer and the formation of the main metabolites, lansoprazole sulfone and 5-hydroxylansoprazole, in the presence of human liver microsomal enzymes. METHODS: Human liver microsomes or recombinant cytochrome P450 (CYP) enzymes were incubated with either (+/- )-, (+)-, or (-)-lansoprazole in the presence of reduced nicotinamide adenine dinucleotide phosphate. The metabolic consumption of lansoprazole enantiomers was estimated from the amounts of enantiomers consumed by microsomal enzymes after incubation at 37 degrees C for 60 min. Metabolites of lansoprazole, lansoprazole sulfone, and 5-hydroxylansoprazole were determined after incubation at 37 degrees C for 20 min, and kinetic parameters [Michaelis constant (Km) and maximum velocity (Vmax)] were obtained using Eadie-Hofstee plots. RESULTS: (-)-Lansoprazole was metabolized more preferentially than (+)-lansoprazole in human liver microsomes. Stereoselective sulfoxidation and hydroxylation [(+) > (-)] were observed in human liver microsomes. Strikingly, in sulfoxidation, a significantly higher intrinsic clearance (Vmax,l/Km,l) of (-)-lansoprazole (0.023 +/- 0.001 ml/min/mg) than (+)-lansoprazole (0.006 +/- 0.000 ml/min/mg) was observed. Consequently, sulfoxidation is likely to play an important role in the stereoselective metabolism of lansoprazole enantiomers. P450-isoform specificity for each enantiomer was evident. CYP3A4, which mainly catalyzed sulfoxidation, was more active toward (-)-lansoprazole in either a chiral or racemic drug as a substrate. CYP2C19, which catalyzed hydroxylation, preferentially metabolized (+)-lansoprazole. The consumption of (+)-lansoprazole was markedly inhibited by (-)-lansoprazole, indicating a metabolic enantiomer/enantiomer interaction. However, this alteration of recombinant CYP2C19 specificity for (+)-lansoprazole did not appear in metabolism in human liver microsomes. CONCLUSIONS: Stereoselective metabolism was observed in human liver microsomes, and this stereoselectivity was mainly based on CYP3A4 specificity for preferable metabolism of (-)-lansoprazole.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

Relationship between cervical curvature index (Ishihara) and cervical spine angle (C2--7).

The purpose of this study was to determine the relationship between the cervical curvature index (Ishihara) and the cervical spine angle (C2--7) from both cervical lateral radiographs and a geometrical model. The cervical lateral radiographs of 295 outpatients with no cervical symptoms were reviewed to measure the cervical curvature index (Ishihara) and the cervical spine angle (C2--7). The average cervical curvature index (Ishihara) was 10.9 (SD, 15.3) and the average cervical spine angle (C2--7) was 20.3 (SD, 14.3). A highly significant correlation (0.95; 95% confidence interval [CI], 0.94--0.96) was found between the cervical curvature index (Ishihara) and the cervical spine angle (C2--7). Their linear correlation was also validated in the geometrical model. Their correlation diminished, however, in subjects with an S-shaped cervical spine. The cervical curvature index (Ishihara) and the cervical spine angle (C2--7) were interchangeable, but this interchangeability was lost in the S-shaped cervical spines.

Adolescent↗
PubMed2001

Detection of porphyrin using a short peptide immobilized on a surface plasmon resonance sensor chip.

In this paper the development and feasibility of a novel detection system for a low molecular weight chemical, in which a peptide was utilized as a binding molecule, are described. Surface plasmon resonance (SPR) apparatus was used as a transducer. The porphyrin binding peptide, PSP2, was used as a model peptide ligand, while a porphyrin derivative, H(2)TMpyP, was used as a model low-molecular-weight chemical. PSP2 was covalently immobilized onto the SPR sensor chip and SPR measurement using the PSP2-immobilized chip for various concentrations of porphyrin was carried out. H(2)TMpyP was detectable in the range from 100 ng ml(-1) to 10 microg ml(-1) with a linear correlation and good precision and the PSP2-immobilized chip could be regenerated within 1 min after measurement in this system. From comparison of the detection manners of three porphyrin derivatives, the ability of a short peptide to discriminate between differences in molecular structure was demonstrated. Moreover, the self-assembled monolayer (SAM) of PSP2 was successfully prepared on the gold substrate and H(2)TMpyP could be detected using the PSP2-SAM chip.

Amino Acid Sequence↗
PubMed2001

Glass vials for small volume parenterals: influence of drug and manufacturing processes on glass delamination.

PURPOSE: Studies were initiated to examine the effect of formulation and process variables on the delamination process and also the influence of the glass manufacturing process, supplier, and glass surface treatment. METHODS: Stress testing was performed by exposing filled vials to multiple sterilization cycles followed by accelerated stability testing. Delamination incidence was determined by visual examination, light obscuration (HIAC), and microscopical methods. The inner surface of vials from each supplier and lot were also examined by scanning electron microscopy. RESULTS: Vials sourced from Supplier A had smooth surfaces as demonstrated by SEM examination, whereas vials sourced from Suppliers B and C displayed extensive surface imperfections such as pitting and/or deposits. These imperfections were localized to the vial wall, adjacent to the vial bottom, and increased with sulfate treatment. Delamination incidence increased in those vial lots with increased surface imperfections. Thus, vials sourced from Supplier A had the lowest frequency of delamination. Sulfate treatment and high pH increased delamination incidence to as high as 100%. CONCLUSION: These results demonstrate the importance of the surface morphology created during the vial forming process. Given the diferences observed, final vial selection should include extensive microscopical and product stress testing studies on multiple vial lots.

Antineoplastic Agents↗
PubMed2001

Expression of a cold-responsive Lt-Cor gene and development of freezing tolerance during cold acclimation in wheat (Triticum aestivum L.).

Time-courses of the development of freezing tolerance and the expression of a cold-responsive gene wlt10 were monitored during cold acclimation in wheat (Triticum aestivum L.). Bioassay showed that cold acclimation conferred much higher freezing tolerance on a winter cultivar than a spring cultivar. Northern blot analysis showed that the expression of wlt10 encoding a novel wheat member of a cereal-specific LT-COR protein family was specifically induced by low temperature. A freezing-tolerant winter cultivar accumulated the mRNA more rapidly and for a longer period than a susceptible spring cultivar. The increase in the amount of mRNA was temporary but the peak occurred at the time when the maximum level of freezing tolerance was attained. The mRNA accumulated more in the leaves than in the roots, and different light/dark regimes modulated the level of mRNA accumulation. Genomic Southern blot analyses using the nulli-tetrasomic series showed that the wlt10 homologues were located on the homologous group 2 chromosomes.

Acclimatization↗
PubMed2001

Measurement of the length of the a helical section of a peptide directly using atomic force microscopy.

Using atomic force microscopy (AFM), the length of the alpha-helix structure of poly-L-lysine was investigated by stretching the peptide directly, one molecule at a time. In the absence of urea, many rupturing points that seemed to be due to the breaking of some hydrogen bonds were observed in force-extension curves, while these points were never observed in the presence of 8 M urea. In the presence of 0.4 or 1.6 M urea, both force-extension curve types were observed. Total peptide elongation for each condition was calculated from force-extension curves reflecting the alpha-helix rupturing process. The experimental value of total elongation divided by the theoretical value of total alpha-helix elongation yields the alpha-helix content. This value was compatible with circular dichroism (CD) measurement results. This suggests that peptide conformation and content of the alpha-helix on a single molecule scale can be investigated by direct mechanical measurement using atomic force microscopy.

Circular Dichroism↗