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Biomedical subjects

S Ohno

Publications and source records attributed to S Ohno.

At least 91 records · Page 5Linked to original sources
PubMed2001

Revised diagnostic criteria for Vogt-Koyanagi-Harada disease: report of an international committee on nomenclature.

PURPOSE: To present revised criteria for the diagnosis of Vogt-Koyanagi-Harada disease, a chronic, bilateral, granulomatous ocular and multisystem inflammatory condition of unknown cause. METHODS: Diagnostic criteria and nomenclature were subjects of discussion at the First International Workshop on Vogt-Koyanagi-Harada Disease on October 19-21, 1999, at the University of California, Los Angeles, Conference Center, Lake Arrowhead, California. A committee appointed by the workshop participants was charged with drafting revised criteria for Vogt-Koyanagi-Harada disease, based on discussions held during the conference. This article is the consensus committee report. RESULTS: New criteria, taking into account the multisystem nature of Vogt-Koyanagi-Harada disease, with allowance for the different ocular findings present in the early and late stages of the disease, were formulated and agreed upon by the committee. These criteria are based on additional knowledge and experience of experts in the field and are believed to reflect disease features more fully than previously published criteria. CONCLUSIONS: The revised definition of Vogt-Koyanagi-Harada disease, with expanded diagnostic criteria, will facilitate performance of studies involving homogeneous populations of patients, at various stages of disease, that address unanswered questions regarding treatment and disease mechanisms.

California↗
PubMed2001

Esophageal resection in elderly esophageal carcinoma patients: improvement in postoperative complications.

BACKGROUND: Advanced age is considered to be a relative contraindication for radical esophagectomy with a three-field lymph node dissection. METHODS: Preoperative risks, postoperative morbidity and mortality, and long-term survival in 55 elderly patients (> or =70 years) who had undergone extensive esophagectomy for esophageal carcinoma were compared with those of 149 younger patients (<70 years). RESULTS: Elderly patients had worse preoperative cardiopulmonary function and had more frequent postoperative cardiopulmonary complications compared with younger patients (p < 0.05). The postoperative death rate was not statistically different between the elderly (10.9%) and younger groups (5.4%). When the study period was divided into an early and a late phase, the postoperative death rate dropped significantly (p < 0.05) in recent years (1.4%) when compared with the previous era (10.0%). The overall survival rates were not different between elderly and younger patients. CONCLUSIONS: Preoperative cardiopulmonary risk factors and postoperative complications after esophagectomy were more frequently noticed in elderly patients than in younger patients. A dramatic improvement in postoperative death was noticed in recent years. The long-term survival of elderly patients after extended esophagectomy was almost similar to that in younger patients.

Aged↗
PubMed2001

Regulation of hyaluronan synthase gene expression in human periodontal ligament cells by tumour necrosis factor-alpha, interleukin-1beta and interferon-gamma.

Accumulation and fragmentation of hyaluronic (HA) accompanies the inflammatory changes in the periodontium and gingival crevicular fluid are involved in periodontitis, but the mechanism for this is unknown. Recently, three human hyaluronan-synthase (HAS1, 2, and 3) genes have been cloned and characterised as synthesising hyaluronans of different molecular weights. Both HAS1 and HAS2 synthesise high molecular-weight HA, whereas HAS3 produces lower molecular weight HA. In the present study the regulation of HAS genes by cytokines in cultured human periodontal ligament (PDL) cells was investigated using a novel real-time fluorescence polymerase chain reaction detection system. Human PDL cells derived from premolars were cultured with or without tumour necrosing factor (TNF)-alpha (1-100 ng/ml), interleukin (IL)-1beta (0.1-10 ng/ml) and interferon (IFN)-gamma (1-100 ng/ml). Expression of HAS mRNA was assessed in cultured cells treated with these cytokines for 0-24 h. The expression of HAS2 mRNA was enhanced about 4.5- and 2.2-fold at maximum after 3-h stimulation with 10 ng/ml TNF-alpha and 1 ng/ml IL-1beta, respectively, whereas IFN-gamma exerted little effect on HAS2 or HAS3 mRNA expression during the experiment. Expression of HAS3 mRNA was increased by about 14- and 10-fold after 3-h stimulation with 10 ng/ml TNF-alpha and 1 ng/ml IL-1beta, respectively. These results suggest that TNF-alpha and IL-1beta regulate HAS expression, and consequently may result in an accumulation of HA and an increase in HA of a lower molecular-weight.

Cells, Cultured↗
PubMed2001

Bacterial Infection in the Conjunctiva of Patients with Adenoviral Conjunctivitis.

Purpose: We evaluate the microbiological features of mixed infection in adenovirus-infected conjunctiva.Subjects: Isolation of bacteria was performed in 82 samples of adenoviral conjunctivitis at six eye clinics in Japan.Methods: For microbiological diagnosis, we performed immunochromatography (IC) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis for detection and serotyping of adenovirus, and PCR for detection of herpes simplex virus (HSV) and Chlamydia trachomatis antigens out of 82 samples with adenoviral conjunctivitis.Results: Pathogenic bacteria were isolated in 6 samples out of 82. Out of these 6 cases, 5 samples were gram-negative rods and most of them were Flavobacterium meningosepticum (4 samples). Adenovirus type 8 was isolated from all these mixed infection cases. However, HSV-1 and Chlamydia trachomatis were not found.Conclusions: From these results, it is suggested that gram-negative rods, especially F. meningosepticum, are the most common bacteria causing mixed bacterial infection in adenoviral conjunctivitis.

Journal Article↗
PubMed2001

A species-selective allelopathic substance from germinating sunflower (Helianthus annuus L.) seeds.

From the exudate of germinating sunflower (Helianthus annuus L.) seeds was isolated a stereoisomer of diversifolide, 4, 15-dinor-3-hydroxy-1(5)-xanthene-12,8-olide (designated sundiversifolide) as determined by analysis of its IR, APCI-, ESI- and HR-MS and 13C and 1H NMR spectra. This substance inhibited shoot and root growth of cat's-eyes by about 50% at a concentration of 30 ppm. It also showed species-selective activity on the shoot and root growth of tested plants. When cat's-eyes seeds were incubated together with sunflower seeds, the cat's-eyes growth was inhibited. Furthermore, it was detected from an extract of river sand when sunflower seeds were incubated on the sand. These results indicate that sundiversifolide has an allelopathic function in sunflower plants.

Helianthus↗
PubMed2001

Microsatellite mapping of a susceptible locus within the HLA region for Behçet's disease using Jordanian patients.

Behçet's disease (BD) has been established to be associated with HLA-B51. However, it has not been revealed whether the HLA-B51 gene itself or another gene located near the HLA-B gene is directly involved in the pathogenesis of BD. Previously, using Japanese BD patients, our group has narrowed down a BD-causative gene to 46 kb between the MICA and HLA-B genes by means of fine mapping analysis with eight microsatellite markers distributed within a 1100 kb segment around the HLA-B gene. To know whether this mapping result is generally observed in BD of another population we have investigated repeat polymorphisms of the same microsatellite markers in Jordanian BD patients. Furthermore, we have evaluated these data by Mantel-Haenzel stratified analysis to find out a primarily associated locus for BD. As a result, HLA-B51 was found to be the most strongly and primarily associated marker. This result suggests that the pathogenic gene of BD is HLA-B51 itself, but unlikely to be other genes located in the vicinity of HLA-B.

Adolescent↗
PubMed2001

Simulation of air-bag impact on post-radial keratotomy eye using finite element analysis.

PURPOSE: To determine the physical and mechanical conditions of an impacting air bag that causes corneal rupture in a post-radial keratotomy (RK) eye using a simulation model of the human eye. SETTING: Numerical simulation study on a computer. METHODS: The simulations were performed by a computer using the finite element analysis program PAM-CRASH (Nihon ESI). The air bag was set to impact the surface of a post-RK eye with 4, 6, or 8 corneal incisions at various velocities. Strain on the corneal tissue including scarred incisions exceeding 9.0% was assumed to indicate the possibility of corneal rupture. RESULTS: At a medium velocity of 30 m/s, corneal rupture was likely to occur. At an air-bag impact velocity of 40 m/s, 3 of 4, 5 of 6, and 8 of 8 incisions were likely to rupture in the case of 4-, 6-, and 8-incision procedures, respectively, leading to likely globe rupture in all situations. Lacerations extended beyond the incisions and involved the intact cornea at a velocity of 40 m/s. If the corneal tissue strength reduction was increased to 90%, most incisions were likely to rupture at impact velocities greater than 35 m/s in all incision procedures. CONCLUSIONS: The results could partly reflect a reported case of globe rupture after RK and suggest that severe ocular trauma can be caused in the post-RK eye by air bags at ordinary impact velocities.

Air Bags↗
PubMed2001

Intercellular junctions and cellular polarity: the PAR-aPKC complex, a conserved core cassette playing fundamental roles in cell polarity.

Two PDZ-domain-containing adapter-like proteins, PAR-3 and PAR-6, and a protein kinase, atypical protein kinase C (PKC), cooperate together to establish cell polarity in a variety of biological contexts. These include asymmetric cell division in early Caenorhabditis elegans embryo and Drosophila neuroblasts, as well as the establishment and maintenance of apical-basal polarity in Drosophila and mammalian epithelial cells. Recent studies on the role of this PAR-aPKC complex in epithelial cell polarization provide new insights into the molecular basis of epithelial junctional formation and cell polarity.

Animals↗
PubMed2001

Anionic sites in articular cartilage revealed by polyethyleneimine staining.

Articular cartilage is a unique tissue that contains neither blood vessels nor nerves, and that performs mechanical loading during joint movement. These properties are endowed by abundant glycosaminoglycans (GAGs), which are capable of retaining water-soluble substances. The GAGs attach to core proteins and form proteoglycans. Although many studies have focused on proteoglycans and collagen fibrils in cartilage, little is known about the nature of the negative charge of GAGs. Recently, we investigated this subject using a cationic dye, polyethyleneimine (PEI), with several different techniques such as pre-embedding, post-embedding, and quick-freezing and deep-etching methods. In addition, we investigated whether the anionic charge is altered at low pH, using PEI and cationic colloidal gold (CCG) labeling. The shapes of PEI-positive structures revealed by the pre-embedding method varied at different pHs. Three-dimensional analysis using the quick-freezing and deep-etching method demonstrated that meshwork structures composed of fine filaments were decorated with tiny PEI granules. Additionally, the meshwork structure was broken down after chondroitinase ABC digestion. These data indicate that the large PEI deposits observed in pre-embedding preparations are, at least in part, artificial images, and that the meshwork structure consists of chondroitin sulfate-retaining anionic sites. Low pH conditions changed PEI or CCG labeling patterns, showing that negative charges of GAGs in articular cartilage are altered under environmental pH conditions. These findings demonstrate that binding capacities of anionic sites to water-soluble or ionic substances are greatly affected by pH alterations without actually decreasing the number of anionic sites. Therefore, to understand cartilage dynamics and the pathogenesis of joint diseases in greater detail, alterations of anionic charge during mechanical loading or under pathological conditions should be examined in future studies.

Animals↗
PubMed2001

Clinicopathologic factors correlated with number of metastatic lymph nodes in oesophageal cancer.

BACKGROUND: The number of metastatic lymph nodes is applied to the staging system of gastric cancer and colorectal cancer. However, it has not been evaluated in oesophageal cancer. PATIENTS AND METHODS: Of 258 patients with primary squamous cell carcinoma of the thoracic oesophagus between February 1981 and December 1999, 160 underwent three-field oesophagectomy with a curative intent. Clinicopathologic characteristics of those 160 patients were retrospectively investigated according to the number of metastatic lymph nodes. RESULTS: Seventy-eight patients had no lymph node metastases and 82 (51.3%) had lymph node metastases; 51 [31.9%)] had between 1 and 4 positive lymph nodes, and 31 (19.4%) had > or =5. The number of metastatic lymph nodes was significantly correlated with tumour size, macroscopic classification, histological differentiation, pT, pN, and vessel invasions. Multivariate analysis showed that lymph vessel invasion (relative risk 12.6), histological differentiation (relative risk 4.2), and tumour size (relative risk 3.8) were independent factors correlated with number of metastatic lymph nodes. The number of metastatic lymph nodes was also well correlated with the Japanese nodal level and TNM stage, respectively (p<0.001). The 5-year disease-specific survival rate according to the number of positive lymph nodes was 90% for patients without lymph node metastases, 52.2% with 1-4, and 28.9% with > or =5, respectively, p<0. 0001; 0 vs 1-4, p<0.05; 1-4 vs > or =5). CONCLUSION: The number of positive lymph nodes is well correlated with tumour progression and provides a useful prognostic indicator after oesophagectomy for oesophageal cancer.

Aged↗
PubMed2001

HLA class I genotyping including HLA-B*51 allele typing in the Iranian patients with Behçet's disease.

It is well known that Behçet's disease (BD) is strongly associated with human leukocyte antigen (HLA) B51 in many ethnic groups. However, there has been no published report as yet with respect to this association among the Iranian people. Furthermore, since it is now known that the B51 antigen can be encoded by 21 alleles, B*5101-B*5121, we performed HLA-B*51 allele typing as well as HLA class I genotyping of 48 Iranian patients with this disease. As a result, the frequency of the B*51 allele was significantly higher (62.1%) in the patient group as compared with the ethnically matched control group (31.8%) (Pc=0.067, R.R.=3.51). In the genotyping of B*51 alleles, 33 out of the 36 B*51-positive patients possessed B*5101 and the remaining 3 carried B*5108. This study revealed that Iranian patients with BD also had a strong association with HLA-B51. In addition, this significantly high incidence of HLA-B*51 was found to be caused by an increase in both the HLA-B*5101 and HLA-B*5108 alleles. However, there was no significant difference in the HLA-B*51 allelic distribution between the patient and control groups.

Alleles↗
PubMed2001

The absence of disease-specific polymorphisms within the HLA-B51 gene that is the susceptible locus for Behçet's disease.

Behçet's disease is known to be associated with HLA-B51 in many different populations. Genetic evidence supports that the susceptible gene for Behçet's disease is the HLA-B51 allele at the HLA-B locus. This study was aimed to determine the HLA-B51 nucleotide sequence variation in three Behçet's disease patients and three healthy controls in order to elucidate if any disease specific mutations or polymorphisms may exist in the HLA-B51 gene of patients. Long-range polymerase chain reaction (PCR) was first carried out to give a PCR-amplified product of 9.5 kb which was then used as a template for nested PCR to give a final amplified product of 4.2 kb. This final product containing the 1.3-kb promoter/enhancer region and the entire HLA-B gene except for a 363-bp 3' terminal end segment encoding the 3' untranslated region was subcloned by the BP cloning technique and sequenced. The sequencing results showed that all the patients possessed the HLA-B*51011 allele, and there were no differences in the exonic nucleotide sequences between the three Behçet's disease patients and the three healthy controls. The HLA-B*51011 intronic and promoter/enhancer nucleotide sequences from the three patients had 22 single nucleotide polymorphisms (SNPs), a single insertion of 6 bp and a single deletion of 2 bp. On the other hand, the three healthy controls had 24 SNPs in their intronic and promoter/enhancer regions. However, none of these polymorphisms in the patients were specific for the disease. Therefore, these results clearly demonstrate that the HLA-B exonic sequence that encodes the HLA-B51 allele is the real pathogenic factor in Behçet's disease.

5' Flanking Region↗
PubMed2001

HLA-B*51 allele analysis by the PCR-SBT method and a strong association of HLA-B*5101 with Japanese patients with Behçet's disease.

Behçet's disease (BD) is known to be associated with human leukocyte antigen (HLA) B51 in many different ethnic groups. An increased incidence of HLA-B51 in the patient group has also been reported in a Japanese population. Recently, the B51 antigen has been identified to comprise 21 alleles, B*5101-B*5121. Further, not only HLA-B*5101 but also HLA-B*5108 were found to be relatively increased in the patient groups among Italian and Saudi Arabian populations. Therefore, we performed HLA-B*51 allele genotyping by the polymerase chain reaction-sequencing based typing (PCR-SBT) method in order to investigate whether there is any correlation of one particular B51-associated allele with Japanese BD. Ninety-six Japanese patients with BD and 132 healthy Japanese volunteers were enrolled in this study. As a result, the phenotype frequency of the B51 antigen was confirmed to be remarkably increased in the patient group as compared to the ethnically matched control group (59.4% in patients vs. 13.6% in controls; Pc=0.0000000000098, R.R.=9.3). In the B*51 allele genotyping, 56 out of 57 B51-positive patients were defined as B*5101 and the remaining one was B*5102. In contrast, all of 18 B51-positive normal controls were B*5101. None of the Japanese patients and healthy controls carried the HLA-B*5108 allele. This study revealed that B*51 allelic distribution in Japanese was different from those in Italian and Saudi Arabian populations, and that the significantly high incidence of the HLA-B51 antigen in the Japanese BD patient group was mostly caused by the significant increase of the HLA-B*5101 allele.

Alleles↗
PubMed2001

Clathrin-dependent and clathrin-independent endocytosis are differentially sensitive to insertion of poly (ethylene glycol)-derivatized cholesterol in the plasma membrane.

We examined the effect of a cholesterol derivative, poly (ethylene glycol) cholesteryl ether on the structure/function of clathrin-coated pits and caveolae. Addition of the compound to cultured cells induced progressive smoothening of the surface. Markedly, when the incorporated amount exceeded 10% equivalent of the surface area, fluid pinocytosis, but not endocytosis of transferrin, became inhibited in K562 cells. In A431 cells, both clathrin-independent fluid phase uptake and the internalization of fluorescent cholera-toxin B through caveolae were inhibited with concomitant flattening of caveolae. In contrast, clathrin-mediated internalization of transferrin was not affected until the incorporated poly (ethylene glycol) cholesteryl ether exceeded 20% equivalent of the plasma membrane surface area, at which point opened clathrin-coated pits accumulated. The cells were ruptured upon further addition of poly (ethylene glycol) cholesteryl ether. We propose that the primary reason for the differential effect of poly (ethylene glycol) cholesteryl ether is that the bulk membrane phase and caveolae are both more elastic than the rigid clathrin-coated pits. We analyzed the results with the current mechanical model (Rauch and Farge, Biophys J 2000;78:3036-3047) and suggest here that the functional clathrin-lattice is much stiffer than typical phospholipid bilayers.

Biological Transport↗
PubMed2001

Human homologues of the Caenorhabditis elegans cell polarity protein PAR6 as an adaptor that links the small GTPases Rac and Cdc42 to atypical protein kinase C.

BACKGROUND: Asymmetric cell division in the Caenorhabditis elegans embryos requires products of par (partitioning defective) genes 1-6 and atypical protein kinase C (aPKC), whereas Cdc42 and Rac, members of the Rho family GTPases, play an essential role in cell polarity establishment in yeast and mammalian cells. However, little is known about a link between PAR proteins and the GTPases in cell polarization. RESULTS: Here we have cloned cDNAs for three human homologues of PAR6, designated PAR6alpha, beta and gamma, comprising 345, 372 and 376 amino acids, respectively. The PAR6 proteins harbour a PDZ domain and a CRIB-like motif, and directly interact with GTP-bound Rac and Cdc42 via this motif and with the aPKC isoforms PKCiota/lambda and PKCzeta via the N-terminal head-to-head association. These interactions are not mutually exclusive, thereby allowing the PAR6 proteins to form a ternary complex with the GTPases and aPKC, both in vitro and in vivo. When PAR6 and aPKC are expressed with a constitutively active form of Rac in HeLa or COS-7 cells, these proteins co-localize to membrane ruffles, which are known to occur at the leading edge of polarized cells during cell movement. CONCLUSION: Human PAR6 homologues most likely play an important role in the cell polarization of mammalian cells, by functioning as an adaptor protein that links activated Rac and Cdc42 to aPKC signalling.

Amino Acid Sequence↗
PubMed2001

PAR-6 regulates aPKC activity in a novel way and mediates cell-cell contact-induced formation of the epithelial junctional complex.

BACKGROUND: PAR-6, aPKC and PAR-3 are polarity proteins that co-operate in the establishment of cell polarity in Caenorhabditis elegans and Drosophila embryos. We have recently shown that mammalian aPKC is required for the formation of the epithelia-specific cell-cell junctional structure. We have also revealed that a mammalian PAR-6 forms a ternary complex with aPKC and ASIP/PAR-3, and localizes at the most apical end of the junctional complex in epithelial cells. RESULTS: The ternary complex formation and junctional co-localization of PAR-6 with aPKC and ASIP/PAR-3 are observed during the early stage of epithelial cell polarization. In addition, over-expression of the PAR-6 mutant with CRIB/PDZ domain in MDCK cells disturbs the cell-cell contact-induced junctional localization of tight junction proteins, as well as inhibiting TER development. Furthermore, the binding of Cdc42:GTP to the CRIB/PDZ domain of PAR-6 enhances the kinase activity of PAR-6-bound aPKC. Detailed analyses suggest that the binding of PAR-6 to aPKC has the intrinsic potential to activate aPKC, which is only released when Cdc42:GTP binds to the CRIB/PDZ domain. CONCLUSION: The results indicate the involvement of PAR-6 in the aPKC function which is required for the cell-cell adhesion-induced formation of epithelial junctional structures, possibly through the cooperative regulation of aPKC activity with Cdc42.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Cloning and characterization of the T-box gene Tbx6 in Xenopus laevis.

Tbx6 is a member of the T-box gene family. Studies of knockout mice indicate that Tbx6 is involved in somite differentiation. In the present study, we cloned Tbx6 from another vertebrate species, namely Xenopus laevis, and studied its roles in development. The expression of Tbx6 in Xenopus started from the early gastrula stage, reached a peak during the late gastrula to neurula stages and then declined. Initial expression of Tbx6 was observed in the paraxial mesoderm during the gastrula stage. The Tbx6-expressing region spread anteriorly and ventrally in the neurula stage. In the tailbud stage, the area of expression shrank caudally and was finally restricted to the tip of the tailbud. Overexpression of Tbx6 mRNA in dorsal blastomeres caused atrophy of the neural tube and inhibited differentiation of the notochord. Animal cap explants overexpressing Tbx6 or Tbx6VP16 mRNA, but not Tbx6EnR mRNA, differentiated mainly into ventral mesodermal tissues. This suggests that Tbx6 is a transcriptional activator. Higher doses of Tbx6 or Tbx6VP16 mRNA caused hardly any muscular differentiation. However, coinjection of Tbx6 mRNA with noggin mRNA elicited marked muscle differentiation. These results suggest that Tbx6 is implicated in ventral mesoderm specification but is involved in muscle differentiation when acting together with the dorsalizing factor noggin.

Amino Acid Sequence↗