Biomedical subjects

H Seki

Publications and source records attributed to H Seki.

At least 19 recordsLinked to original sources

PubMed2001

Differential cellular targets of Epstein-Barr virus (EBV) infection between acute EBV-associated hemophagocytic lymphohistiocytosis and chronic active EBV infection.

Unusual Epstein-Barr virus (EBV) infection into T or natural killer cells plays a pivotal role in the pathogenesis of acute EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH) and chronic active EBV infection (CAEBV). The precise frequency and localization of EBV genome in lymphocyte subpopulations especially within T-cell subpopulations are unclear in these EBV-related disorders. This study analyzed the frequency of EBV-infected cells in circulating lymphocyte subpopulations from 4 patients with acute EBV-HLH and 4 with CAEBV. EBV- encoded small RNA-1 in situ hybridization examination of peripheral blood lymphocytes showed a significantly higher frequency of EBV-infected cells of 1.0% to 13.4% in EBV-HLH and 1.6% to 25.6% in CAEBV, respectively. The patterns of EBV infection in lymphocyte subpopulations were quite different between acute EBV-HLH and CAEBV. EBV infection was predominant in CD8(+) T cells in all EBV-HLH patients, whereas the dominant EBV-infected cell populations were non-CD8(+) lymphocyte subpopulations in CAEBV patients. Phenotypical analysis revealed that EBV-infected cell populations from both EBV-HLH and CAEBV were activated. There was no predominance of any EBV substrain of latent membrane protein-1, EBV-associated nuclear antigen (EBNA)-1, and EBNA-2 genes between the 2 abnormal EBV-associated disorders, and self-limited acute infectious mononucleosis. These results showing differential virus-cell interactions between acute EBV-HLH and CAEBV indicated different pathogenic mechanisms against EBV infection between the 2 EBV-associated diseases, which accounts for the difference in clinical manifestations between the 2 diseases.

Acute Disease↗

PubMed2001

Mutation frequencies of EXT1 and EXT2 in 43 Japanese families with hereditary multiple exostoses.

Hereditary multiple exostoses (EXT) is an autosomal dominant bone disease characterized by the formation of cartilage-capped prominences. EXT is genetically heterogeneous with at least four chromosomal loci. Among the four loci, the exostosis type 1 gene (EXT1) and type 2 gene (EXT2) have been cloned. Previous studies have shown that disease-type-specific frequency of mutations is different among various ethnic populations. To determine those frequencies in the Japanese, we conducted a large-scale mutation screening on both genes. In 23 of 43 Japanese families examined, we found 21 different mutations, of which 18 are novel. Seventeen (40%) of the 23 families had a mutation in EXT1 and six (14%) had a mutation in EXT2, suggesting that the former mutations are more frequent than the latter in Japanese EXT families. Of the 17 families with EXT1 mutations, 13 had those causing premature termination of the EXT1 protein and four showed missense mutations, whereas five of the six families with EXT2 mutations had those causing premature termination and one showed missense mutation. Interestingly, all four EXT1 missense mutations occurred in an arginine residue at codon 340 (R340) that is known as a critical site for expression of heparan sulfate glycosaminoglycans, suggesting that the region encompassing the arginine residue may play an important role in the function of the EXT1 protein. These results expand our knowledge of the ethnic difference of EXT and the structure-function relationship of the EXT genes.

DNA↗

PubMed2001

Solitary thyroid metastasis of renal clear cell carcinoma: report of a case.

A case of solitary thyroid metastasis of renal clear cell carcinoma is described. The patient was a 77-year-old Japanese woman, who was referred to our department after a thyroid tumor was identified in May 1999. She had a history of renal clear cell carcinoma of the left kidney, which had been partially resected 3 years previously. Ultrasound sonography demonstrated that a well-demarcated hypoechoic mass containing high-echo spots representing small calcifications, which measured 45 x 34 x 31 mm in size, occupied the left lobe. Computed tomography revealed a low-density mass containing small calcifications. The results of preoperative fine-needle aspiration cytology strongly suggested a clear cell carcinoma metastasizing to the thyroid. A left hemithyroidectomy was performed on July 27, 1999. A histological examination revealed that the neoplasm was composed of tumor cells with abundant clear cytoplasm and round nuclei. The histological characteristics of this thyroid tumor were virtually identical to the renal cell carcinoma resected 3 years previously. Thyroglobulin stained negatively in the clear cells of the resected thyroid tumor in an immunohistochemical analysis. Clinically, the thyroid gland is a rare site of tumor metastasis; however, we should also consider the possibility of metastasis in the case of thyroid tumor patients with a history of renal cell carcinoma.

Aged↗

PubMed2001

Immunohistochemical localization of inducible nitric oxide synthase in synovial tissue of human temporomandibular joints with internal derangement.

The expression and distribution of inducible nitric oxide synthase (iNOS) was examined in 12 samples of human temporomandibular joint (TMJ) with internal derangement (ID) and four control specimens. In the diseased joints, strong or definite iNOS reactivity was expressed in synovial lining and endothelial cells; weaker activity was present in synovial fibroblasts. In contrast, although there was weak expression of iNOS in synovial fibroblasts and endothelial cells in the two control specimens, there was no iNOS staining in the synovial lining cell layers. This original report that iNOS is expressed in the synovial tissue of the temporomandibular joint indicates that nitric oxide is produced locally at least in the synovial lining in these joints when affected by internal derangement.

Adolescent↗

PubMed2001

Molecular cloning and functional analysis of pea cDNA E86 encoding homologous protein to hypersensitivity-related hsr203J.

Clone E86 was isolated as cDNA for elicitor-inducible gene from pea epicotyls by differential screening. The deduced amino acid sequence of E86 showed high homology to hypersensitivity-related protein hsr203J in tobacco and also showed significant homologies to the Ser-active hydrolases, such as mammalian hormone-sensitive lipases, bacterial lipases and esterases. E86 polypeptide possesses consensus amino acid sequence motifs (His-Gly) and (Gly-X-Ser-X-Gly) conserved in lipases and esterases and showed esterase degradation of p-nitrophenyl butyrate. Northern blot analysis revealed that the E86-transcript is abundant in roots and stems and was induced by fungal elicitor in pea epicotyls. However, elicitor-induced accumulation of E86 mRNA was significantly inhibited by the fungal suppressor. Furthermore the expression of the genes encoding E86 and phenylalanine ammonia-lyase was induced within 1 h after the inoculation of a nonpathogen, but it was delayed for 5 h by the inoculation of a compatible pathogen. These results suggest that the elicitor-induced Ser-active hydrolase derived from E86 gene might be related to the plant defense responses.

Journal Article↗

PubMed2001

Cloning and expression of the ferredoxin gene from extremely halophilic archaeon Haloarculajaponica strain TR-1.

The gene encoding a ferredoxin (Fd) from Haloarculajaponica strain TR-1 was cloned and sequenced. Sequence analysis of the cloned Ha. japonica Fd gene revealed that the structural gene consisted of an open reading frame of 387 nucleotides encoding 129 amino acids. The deduced amino acid sequence of Ha. japonica Fd showed 84 to 98% identity with corresponding sequences in other extremely halophilic archaea. The Ha. japonica Fd gene was inserted into the shuttle vector pWL102 and used to transform Ha. japonica. Ha. japonica Fd could then be produced as a fusion with His-Tag (6xHis) in Ha. japonica host cells. The absorption and ESR spectra of the Fd/His Tag fusion protein revealed the presence of a [2Fe-2S] cluster which is characteristic of native Ha. japonica Fd.

Amino Acid Sequence↗

PubMed2001

Effect of the reducing agent on the oxygen-inhibited layer of the cross-linked reline material.

The purpose of this study was to clarify the effect of the reducing agent on the oxygen-inhibited layer of the cross-linked reline material. A commercial autopolymerizing reline resin containing 1,6-hexanediol dimethacrylate as cross-linking agent and 1 wt.% sodium sulphite solution as a reducing agent was prepared. The inhibited layer was observed using an optical transmission microscope under the conditions of the application of sodium sulphite for 0, 1, 5 and 15 min after curing for 10 min in air. As a control, the reline material was cured on sealing from air. Moreover, the three-point flexural strength test was performed under the same conditions. The fracture was then observed using scanning electron microscopy (SEM). Although hardness of the inhibited layer was enhanced after the application of the reducing agent, the layer was still observed. The flexural strength of the control and the groups after application of the reducing agent was significantly higher than the group without reducing agent. SEM examination revealed many polymer beads on the group without reducing agent, whereas polymer beads could not be observed on the groups applying the reducing agent. These results indicated that the application of sodium sulphite was effective in hardening the surface unpolymerized zone.

Analysis of Variance↗

PubMed2001

The 'superficial' peroneal artery: a variation in cutaneous branching from the peroneal artery, nourishing the distal third of the leg.

Two different vascular patterns were encountered in cutaneous branches from the peroneal artery to the posterolateral aspect of the distal third of the leg in 22 flaps from 22 patients who underwent cutaneous or osteocutaneous peroneal flap surgery. In the type 1 vascular pattern, a branch from the peroneal artery, named the 'superficial peroneal artery', nourished the posterolateral aspect of the leg by splitting into several septocutaneous branches. In the type 2 pattern a few septocutaneous branches originated directly from the main peroneal artery and nourished the same area as that fed by the type 1 branch. The type 1 vascular pattern has not been reported to date but was seen in nine out of the 22 consecutive peroneal flaps. The superficial peroneal artery, with its considerable vascular diameter, may serve as a recipient vessel for free flaps or may serve as a donor nutrient vessel for a cutaneous flap, which can be transferred without sacrificing the main peroneal artery. Awareness of these two vascular patterns in the distal third of the leg should also help to reduce the small percentage of skin-flap failures that occur when the cutaneous or osteocutaneous peroneal flap is used.

Adult↗

PubMed2001

Expression of proteinases and inflammatory cytokines in subchondral bone regions in the destructive joint of rheumatoid arthritis.

OBJECTIVE: We previously described abnormalities in the bone marrow of patients with rheumatoid arthritis (RA), but were able to shed little light on the pathogenic roles of inflammatory cytokines and proteinases in joint destruction in the subchondral region in RA. This is the first report to describe the co-localization of cytokines and proteinases in this area. METHODS: Decalcified paraffin-embedded sections from 10 patients with RA and five patients with osteoarthritis (OA) were examined for the immunolocalization of cathepsins B, K and L and the localization of messenger RNAs for interleukin 1beta (IL-1beta), tumour necrosis factor alpha (TNF-alpha) and matrix metalloproteinase 9 (MMP-9). The cells were double-stained with anti-CD68 or anti-prolyl 4-hydroxylase (PH) antibody. RESULTS: An immunohistochemical study confirmed the expression of cathepsins B and L by CD68-positive mononuclear cells at the sites of significant cartilage and bone erosion from the subchondral region in all RA specimens. Osteoclast-like cells showed intense staining for cathepsin K and MMP-9. Osteoblast-like cells strongly expressed MMP-9. Analysis of serial sections revealed that expression of the IL-1beta and TNF-alpha genes occurred near that of the cathepsins and MMP-9 in the subchondral region. CONCLUSION: We conclude that inflammatory cytokines and tissue-damaging proteinases play important roles in joint destruction in the subchondral region in RA.

Adult↗

PubMed2001

Gastrointestinal stromal tumour of the rectum.

Gastrointestinal stromal tumour (GIST) has been immunohistochemically defined as the tumour lacking differentiation towards either leiomyomatous tumour or schwannoma. We report a 75-year-old man who underwent an abdominoperineal resection of a large submucosal tumour of the rectum. The excised specimen was revealed to be an elastic soft tumour, 8 x 7 x 6 cm in size, which histologically consisted of spindle-shaped cells without nuclear atypia. The mitotic count was fewer than 2 per 10 high-power fields. The tumour cells were positive for staining of CD34 and c-kit protein, while the lesions were negative for alpha-smooth muscle actin, HHF-35, neuron-specific enolase, and S-100 protein. The diagnosis of GIST was confirmed by immunohistochemical examination of the tumour. From these findings, the present case is thought to be potentially malignant, and a long-term follow-up observation is needed for the case.

Aged↗

PubMed2001

[Survey of vaccination for physically-handicapped and epileptic children].

We studied immunization for 128 handicapped patients, from 3 to 15 years of age, in a Seishi Gakuen Hospital, with 8 vaccines: diphtheria-purified acellular pertussis-tetanus combined (DPT), BCG, polio, measles, rubella, mumps, varicella, and Japanese B encephalitis. The rate of vaccination in these patients was lower than in healthy children at 3 years of age in Kanazawa City. There was no significant difference between patients with and without epilepsy. The rate was higher in the hospitalized patients than in the outpatients. More than 90% of the hospitalized patients was immunized against influenza under informed consent in 1997 and 1998. Despite pandemics of influenza in Kanazawa City, where the hospital was located, the period of fever by influenza was significantly shorter in our patients in both 1997 and 1998 than in 1996. Although a half of our patients had epilepsy, they were safely vaccinated with few side effects.

Adolescent↗

PubMed2001

[A case of primary adenocarcinoma of the female urethra].

A 53-year-old female visited our hospital with a complaint of acute urinary retention. Transvaginal ultrasonography, computed tomography and magnetic resonance imaging showed extreme thickening of the urethral wall. Histopathological examination of the transvaginal needle biopsy suggested well-differentiated adenocarcinoma. She underwent total cysto-urethrectomy with partial vaginal wall resection and ileal conduit urinary diversion. Pathological diagnosis of the tumor was columnar adenocarcinoma invading into the vaginal wall and periurethral connective tissue. Fifty-eight cases of primary adenocarcinoma of the female urethra in the Japanease literature are briefly reviewed.

Adenocarcinoma↗

PubMed2000

Anomalous substituent effects in the bischler-napieralski reaction of 2-aryl aromatic formamides

Treatment of some 1-naphthylformamides (or formanilides) possessing a 2,4,5-trioxygenated phenyl substituent at the 2-position with POCl(3) caused an unprecedented carbon insertion reaction into a benzene ring, producing 7-5 ring (azaazulene) systems as valence isomers of isoquinoline skeletons. Precise examination of this abnormal Bischler-Napieralski reaction (BNR) using various substrates led to the following scope and limitations: (i) the 7-5 ring systems were constructed when either 2-alkoxy-4, 5-methylenedioxyphenyl- or 4,5-dialkoxy-2-hydroxyphenyl-substituted formamides were used as a starting substrate; (ii) in the former case the formyl carbon was inserted into the C(1)-C(6) bond of the 2-phenyl group, and normal isoquinoline cyclization competed with an abnormal carbon insertion reaction; (iii) the presence of a hydroxy group at the 2'-position as in the latter cases caused exclusive carbon insertion, in which alternative C(1)-C(2) insertion products were quantitatively formed; (iv) 3, 6-dimethoxy-2-hydroxyphenyl-substituted formanilide electronically equivalent to 4,5-dialkoxy-2-hydroxy derivatives produced an indole-pyrone as an abnormal BNR product. Theoretical approaches using the PM-3 method indicated that these abnormal BNRs could be triggered by ipso attack at the 1'-position yielding spiro intermediates. Ring cleavege of the six-membered ring in the spiro intermediates to a ketene function followed by recyclization was proposed for the 2'-hydroxy-directed abnormal BNRs leading to the C(1)-C(2) insertion product or the indole-pyrone derivative.

Journal Article↗

PubMed2000

Modified guanidines as potential chiral superbases. 2. Preparation Of 1,3-unsubstituted and 1-substituted 2-iminoimidazolidine derivatives and a related guanidine by the 2-chloro-1, 3-dimethylimidazolinium chloride-induced cyclization of thioureas

Simple preparation methods for modified guanidines were explored for new chiral superbases. Thus, (4S,5S)-4,5-diphenyl- and diastereomeric cyclohexane-fused 2-iminoimidazolidines were prepared from (1S,2S)-1,2-diphenylethylenediamine and (1R,2R)- or (1S,2S)-1, 2-diaminocyclohexanes through cyclization of protected thiourea intermediates with 2-chloro-1,3-dimethylimidazolinium chloride (DMC) as a key reaction. In the (4S,5S)-4,5-diphenyl series 1-methyl-2-iminoimidazolidines and 2-diethylaminoimidazoline were also prepared as related guanidines.

Journal Article↗

PubMed2000

Modified guanidines as potential chiral superbases. 3. Preparation Of 1,4,6-triazabicyclooctene systems and 1,4-disubstituted 2-iminoimidazolidines by the 2-chloro-1,3-dimethylimidazolinium chloride-induced cyclization of guanidines with a hydroxyethyl substituent

Simple preparation methods of modified guanidines have been explored as potential chiral superbases. Thus, 3,7,8-trisubstituted and 3,6,7, 8-tetrasubstituted 1,4,6-triazabicyclooctene systems were prepared from (1S,2S)-1,2-diphenylethylenediamine through stepwise 2-chloro-1, 3-dimethylimidazolinium chloride (DMC)-induced cyclizations of protected thioureas to the corresponding 2-iminoimidazolidines and then of 2-(2-hydroxyethylimino)imidazolidines to the bicyclic systems. Linear guanidines with a 2-hydroxyethyl functional group were prepared by the reaction of carbodiimides with 2-amino alcohols. Reaction of linear-type guanidines with DMC followed by base treatment afforded 1,4-disubstitued 2-iminoimidazolidines. Furthermore, another type of 1,4,6-triazabicyclooctene was also prepared through double DMC-induced cyclization of guanidines with two 2-hydroxyethyl substituents.

Journal Article↗

PubMed2000

Biosorption of Heavy Metal Ions to A Marine Microalga, Heterosigma akashiwo (Hada) Hada.

A fundamental study of the application of marine microalga to the aqueous-phase separation of toxic heavy metals was carried out. The biosorption characteristics of cadmium and lead ions were determined with marine microalga, Heterosigma akashiwo (Hada) Hada, which was inactivated by steam sterilization. A simple metal-binding model was used for the description of metal-binding data. The results showed that the biosorption of bivalent metal ions to H. akashiwo was due to monodentate binding to two different types of acidic sites: carboxylic- and phosphatic-type sites. Copyright 2000 Academic Press.

Journal Article↗

PubMed2000

Immunostained cathepsins B and L correlate with depth of invasion and different metastatic pathways in early stage gastric carcinoma.

BACKGROUND: With the recent development of minimal treatment for early stage gastric carcinoma, identifying specific indicators of the metastatic potential of primary tumors has become more important. Cathepsin B and cathepsin L, both lysosomal cysteine proteases, degrade the extracellular matrix during tumor progression. Although many studies have shown their relation to human cancer progression, little is known about their roles in the early stage. The clinicopathologic significance of cathepsins was therefore studied in early stage gastric carcinoma. METHODS: Expression of both cathepsins was studied immunohistochemically in 51 tissue specimens from gastric carcinomas that invaded the submucosal layer or muscularis propria. The relation between their expression and clinicopathologic factors was analyzed. RESULTS: Both cathepsins were expressed at higher levels in tumors that invaded the muscularis propria than in those within the submucosa (P < 0.05). In addition, tumors with lymphatic invasion showed higher cathepsin B expression than those without it (P < 0.05), whereas tumors with venous invasion showed higher cathepsin L expression than those without it (P < 0.05). No other clinicopathologic factors correlated with expression of either cathepsin. CONCLUSIONS: Tumors with overexpression of cathepsins have powerful potential for invasiveness in the early stage of gastric carcinoma. Moreover, the authors hypothesize that cathepsins may be one of the determinants of the metastatic route. To the authors' knowledge, this is the first report on specific proteases concerning the mode of metastasis, and the results of this study suggest that therapeutic strategies for early stage gastric carcinoma might need to be changed according to the status of cathepsins.

Adult↗

PubMed2000

Adsorption of Water-Soluble Proteins onto Bubbles in Continuous Foam Separation.

The mechanism of water-soluble protein enrichment in continuous foam separation was studied. The liquid flow rate and the protein concentration in the foam phase were measured at various heights from the interface between the bulk liquid and foam layer, and the intrinsic values at the interface were estimated by the extrapolation method to determine the accurate adsorption density on the bubble surface. Ovalbumin (OA) and hemoglobin (HB) were used as the soluble proteins. The solution pH values were varied from 3.5 to 6.0 for OA and from 6.0 to 8.0 for HB. The experimental isotherms for OA and HB were compared to the Langmuir isotherm, and the two adsorption parameters of the equilibrium constant, K, and the saturated density, gamma, at each pH were determined. Both gamma values obtained for OA and HB showed maxima at their isoelectric point (pH 4.6 for OA and pH 6.8 for HB). Assuming that OA and HB molecules are spherical in shape and are adsorbed on the bubble surface in a close-packed structure at saturation, the calculated diameters for OA and HB molecules were quite similar to the literature values. The variation in gamma for both OA and HB is discussed qualitatively in relation to the net charge of the protein molecule. Copyright 2000 Academic Press.

Journal Article↗