Biomedical subjects

T Honda

Publications and source records attributed to T Honda.

At least 199 records · Page 11Linked to original sources

PubMed1999

Factors influencing the development of hemolytic uremic syndrome caused by enterohemorrhagic Escherichia coli infection: from a questionnaire survey to in vitro experiment.

Enterohemorrhagic Escherichia coli (EHEC) is known as an etiological agent of not only hemorrhagic colitis, but also hemolytic uremic syndrome (HUS) and other serious complications. In this paper, a summary of the results, especially in relation to possible factors involving HUS complication, of a questionnaire survey conducted on the occasion of the massive EHEC outbreak in Sakai city in 1996, is presented. A brief review of the virulence factors and pathogenic mechanism involved in the development of HUS in EHEC infection is also described.

Adolescent↗

PubMed1999

Dual roles of proteasome in the metabolism of presenilin 1.

Presenilin 1 (PS1) has been identified as a causative gene for most early-onset familial Alzheimer's disease. Biochemical studies revealed that PS1 exists predominantly as two processed fragments in cells and brain tissues. We prepared stably transfected cells expressing the wild-type and familial Alzheimer's disease-associated mutants of PS1 and investigated the enzyme that participates in the metabolism of PS1. After treatment of the cells with proteasome inhibitors, the full-length PS1 was significantly accumulated. The levels of N- and C-terminal fragments were also increased. The accumulation of PS1 with a deletion of exon 10, which is unable to be processed, on treatment of the transfected cells with lactacystin indicated that proteasome can degrade full-length PS1. A synthetic peptide that includes the processing region of PS1 was cleaved by 20S proteasome at the putative processing sites after Met288 and Glu299. Metabolic labeling experiments showed that the appearance of the N-terminal fragment was attenuated by the inhibitor. Finally, 28-kDa N- and 20-kDa C-terminal fragments were generated by purified PS1 in vitro. These data indicated that the proteasome pathway is involved in PS1 processing. These results demonstrate that the proteasome pathway plays dual roles in processing and degradation of PS1.

Acetylcysteine↗

PubMed1999

Increased glomerular cytosolic phospholipase A2 activity of OLETF rats with early diabetes.

In view of the potential role of prostaglandins (PGs) in development of glomerular hyperfiltration leading to diabetic nephropathy, we studied the temporal relationship of the activity of cytosolic phospholipase A2 (cPLA2), a rate-limiting enzyme for eicosanoid biosynthesis, with hyperfiltration and the histological changes in glomeruli using OLETF rats, a model for non-insulin-dependent diabetes mellitus (NIDDM). Diabetes mellitus and associated histopathological changes, which developed spontaneously by 30-46 weeks after birth of OLETF rats, were accompanied by approximately 65% increase in glomerular cPLA2 activity that showed significant correlations with elevated plasma glucose levels and creatinine clearance. Moreover, mesangial cells cultured for 5 days with high glucose exhibited approximately 2-fold higher cPLA2 activity than those cultured with physiologic level of glucose. These data suggest that increased glomerular cPLA2 activity leads to production of PGs, which may promote the progression of early diabetic glomerular hyperfiltration and subsequent diabetic nephropathy.

Aging↗

PubMed1999

Fat and dietary fiber intake and colon cancer mortality: a chronological comparison between Japan and the United States.

To estimate the role of dietary fiber (DF) and fat in the striking growth of colon cancer mortality in Japan after World War II, we analyzed relations between the above variables in comparison with those in the United States. In the United States, fat intake grew by only one-third over the past 70 years (from 124 g in 1909-1913 to 166 g in 1984), whereas colon cancer mortality increased fourfold (from 5 to 20 per 100,000). In Japan, although fat intake roughly doubled during the 40 years after World War II (from 20 to 38 g), colon cancer mortality grew 5.5-fold (from 2 to 11 per 100,000). It is difficult to give a consistent explanation for the growth patterns of colon cancer mortality in both countries on the basis of fat consumption as a cancer promoter. In the United States, DF intake continuously dwindled at a level always less than in Japan throughout this century. DF intake in Japan also declined rather steadily, except for war time, over the past 80 years. However, with regard to the growth pattern of colon cancer mortality, it began rising steeply around the period when the daily DF intake diminished below 20 g, suggesting the presence of a threshold level in this neighborhood in preventing the development of colon cancer.

Colonic Neoplasms↗

PubMed1999

Human granulosa cells express integrin alpha2 and collagen type IV: possible involvement of collagen type IV in granulosa cell luteinization.

Previously, it has been shown that integrin alpha6beta1 expressed on human granulosa cells regulates luteinization in co-operation with its ligand, laminin. In this study, integrin alpha2 was immunohistochemically demonstrated to be expressed on granulosa and large luteal cells. It was also detected on luteinizing theca interna cells after ovulation. Immunoreactive collagen type IV, which is one of the ligands for integrin alpha2beta1, was detected around granulosa cells in the pre-ovulatory follicles and its expression was rapidly increased during ovulation. By flow cytometry, collagen type IV was detected on the cell surface of luteinizing granulosa cells isolated from pre-ovulatory follicles, confirming the physiological interaction between granulosa cells and collagen type IV. Collagen type IV in follicular fluid was positively related with progesterone concentration. In 4-day cultures of granulosa cells, collagen type IV in the media was significantly increased by human chorionic gonadotrophin (HCG). The progesterone production was significantly attenuated when granulosa cells were cultured on collagen type IV-coated dishes, suggesting that collagen type IV suppresses granulosa cell luteinization. These findings show that collagen type IV, a ligand for integrin alpha2beta1, is rapidly produced around luteinizing granulosa cells during ovulation, probably under the control of luteinizing hormone (LH) and suggest that collagen type IV is a new parameter and/or regulator of granulosa cell luteinization in the periovulatory phases.

Antigens, CD↗

PubMed1999

Unilateral coronal synostosis treated by internal forehead distraction.

A 1-year-old infant with left hemicoronal synostosis was treated by distraction osteogenesis of the craniofacial skeleton using an internal distraction device. Surgery was performed through a coronal incision. The frontal bone and upper half of both orbits were first osteotomized en bloc after minimal epidural dissection of the supraorbital area and no epidural dissection around the coronal osteotomy site. The lateral one fourth of the frontal bone, including the right lateral half of the orbit, was left intact. The internal distraction device was fixed in the left temporal area. A 0.5-mm per day rate of distraction was performed up to an elongation of 17 mm after a 5-day latency period. The distraction device was removed after a consolidation period of 2 months. The results obtained were satisfactory, with symmetry of the forehead, orbit, and nose achieved without complications. The merits of this procedure are no extradural dead space after the operation (which prevents infection), shortened operative time, reduced blood loss, filling in the bone gap created by advancement with new bone, acceptable cosmesis by the parents during distraction, and no fixation device left after the second operation.

Craniosynostoses↗

PubMed1999

Clinical implications of circulating soluble Fas and Fas ligand in patients with acute myocardial infarction.

BACKGROUND: Apoptotic cell death is the major form of myocardial damage produced by coronary ischemic events. OBJECTIVE: To assess whether circulating levels of soluble Fas (sFas), an inhibitor of apoptosis, and sFas ligand, an inducer of apoptosis, in patients with coronary artery disease are greater than normal. METHODS: Forty-seven patients [acute myocardial infarction (AMI) in 17, old myocardial infarction (OMI) in 15, stable angina in 15] and 10 normal control subjects participated in this study. Serum levels of sFas and sFas ligand in all patients were measured, and cardiac catheterizations were performed. RESULTS: Serum levels of sFas were greater than normal only in patients with AMI (4.6 +/- 1.6 ng/ml); the levels were significantly higher than those in patients with OMI (2.1 +/- 0.6 ng/ml) and stable angina (2.2 +/- 0.5 ng/ml), and in normal subjects (2.0 +/- 0.6 ng/ml; P < 0.0001). However, there was no difference among serum levels of sFas ligand for all groups. For patients with AMI, there was no significant correlation between serum levels of sFas and peak levels both of plasma creatine phosphokinase and of plasma myosin light chain type I as clinical indexes of infarct size. However, there were significant correlations between serum levels of sFas and both pulmonary artery wedge pressure (r = 0.767, P = 0.0003) and left ventricular end-diastolic pressure (r = 0.629, P = 0.03). CONCLUSIONS: Circulating sFas increases in concentration in relation to the severity of hemodynamic conditions in patients with AMI, but it is independent from size of infarct. Therefore, circulating sFas could play an important role as the marker of pathophysiologic conditions associated with cardiomyocyte apoptosis in AMI.

Aged↗

PubMed1999

US3 protein kinase of herpes simplex virus type 2 plays a role in protecting corneal epithelial cells from apoptosis in infected mice.

To clarify the biological role of US3 protein kinase of herpes simplex virus type 2 (HSV-2) in vivo, the expression of the viral antigen, the appearance of apoptotic bodies and DNA fragmentation were examined immunohistologically after corneal infection of mice with three different kinds of HSV-2 strain 186: the wild-type virus, a US3-deficient mutant (L1BR1) and its revertant (L1B-11). In both wild-type 186- and L1B-11-infected mice, viral antigen was diffusely found in the corneal epithelium; no apoptotic changes were detected in the epithelial cells. Whereas, in L1BR1-infected mice, HSV-immunoreactivity was localized around the virus-inoculated sites, and a large number of apoptotic bodies were observed in the corneal epithelium with dual-positive reactions for both HSV-immunostaining and TUNEL staining. These results suggest that the US3 protein kinase plays an important role in protecting HSV-2-infected cells from apoptotic death in vivo.

Animals↗

PubMed1999

The gene encoding the prepilin peptidase involved in biosynthesis of pilus colonization factor antigen III (CFA/III) of human enterotoxigenic Escherichia coli.

The assembly of pilus colonization factor antigen III (CFA/III) of human enterotoxigenic Escherichia coli requires the processing of CFA/III major pilin (CofA) by a peptidase, likely another type IV pilus formation system. Western blot analysis of CofA reveals that CofA is produced initially as a 26.5-kDa preform pilin (prepilin) and then processed to 20.5-kDa mature pilin by a prepilin peptidase. This processing is essential for exportation of the CofA from the cytoplasm to the periplasm. In this experiment, the structural gene, cofP, encoding CFA/III prepilin peptidase which cleavages at the Gly-30-Met-31 junction of CofA was identified, and the nucleotide sequence of the gene was determined. CofP consists of 819 bp encoding a 273-amino acid protein with a relative molecular mass of 30,533 Da. CofP is predicted to be localized in the inner membrane based on its hydropathy index. The amino acid sequence of CofP shows a high degree of homology with other prepilin peptidases which play a role in the assembly of type IV pili in several gram-negative bacteria.

Amino Acid Sequence↗

PubMed1999

Increased sensitivity of cholera toxin detection by enzyme-linked immunosorbent assay with chemical immobilization of antibody onto nylon surface providing hydrophobicity.

We developed an improved method to chemically immobilize antibodies on a nylon surface using a styrene maleic anhydride copolymer having an aryl group, which provides hydrophobicity to the nylon surface. We applied it to a modified enzyme-linked immunosorbent assay (slip-ELISA) for the detection of cholera toxin (CT). The sensitivity of slip-ELISA for CT detection was 1,000 times higher than that of conventional methods of physical adsorption using polystyrene plates, and 10 times higher than that of the method of chemical immobilization using maleic anhydride methylvinyl ether copolymer.

Antibodies, Monoclonal↗

PubMed1999

Disappearance of glyceraldehyde 3-phosphate dehydrogenase from erythrocyte membrane by hemolysis with thermostable direct hemolysin of Vibrio parahaemolyticus or Vibrio cholerae El Tor hemolysin.

It is believed that the thermostable direct hemolysin (TDH) of Vibrio parahaemolyticus and El Tor hemolysin (ETH) of Vibrio cholerae damage erythrocytes and other cells by acting as pore-forming toxins. In this study, we found that a protein band with a molecular weight of 37,000 daltons specifically disappeared from erythrocyte membrane after hemolysis by TDH and ETH, but not after hypotonic hemolysis. The 37 kDa band was identified as glyceraldehyde 3-phosphate dehydrogenase (G3PD), a glycolytic enzyme, based on N-terminal 14 amino acid sequencing. The role of G3PD in hemolysis is discussed.

Bacterial Proteins↗

PubMed1999

Development of an enzyme-labeled oligonucleotide probe for detecting the Escherichia coli attaching and effacing A gene.

Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic Escherichia coli (EHEC) can produce attaching and effacing (AE) lesions on intestinal epithelium in vitro and in vivo. A gene necessary to cause the AE lesion has been identified and designated Escherichia coli attaching and effacing A (eaeA) gene. In this study, an alkaline phosphatase (ALP)-conjugated oligonucleotide probe for the eaeA gene was developed and used to detect the eaeA gene among 163 strains of classical EPEC and 25 strains of EHEC O157. The prevalence rates of eaeA gene in the strains of classical EPEC and EHEC O157 were 51.5 and 100%, respectively. The eaeA-positive rate (60.0%) in strains of class I EPEC serogroups (O26, O55, O86, O111, O119, O125, O126, O127, O128ab, and O142) was significantly higher than that (22.9%) in strains of the class II EPEC serogroups (O18, O44, O114) (P<0.01). A total of 109 eaeA-positive classical EPEC and EHEC O157 were positive for fluorescent actin staining (FAS) assay, whereas 79 eaeA-negative classical EPEC were negative. Both the sensitivity and specificity of the eaeA probe versus the FAS assay positivity were 100%. Thus, use of the ALP-conjugated oligonucleotide probe for the eaeA gene would be specific and reliable in identifying the adherence capability of EPEC and EHEC.

Adhesins, Bacterial↗

PubMed1999

Production and partial characterization of antibody to cord factor (trehalose 6,6'-dimycolate) in mice.

Antibody production against the trehalose 6,6'-dimycolate (TDM, cord factor) of Rhodococcus ruber, a non-pathogenic species of the Actinomycetales group, was investigated in mice by repeated intraperitoneal injection of TDM in water-in-oil-in-water micelles without carrier protein. The antigenic TDM was isolated and purified chromatographically from the chloroform-methanol extractable lipids of R. ruber. The hydrophobic moiety of this TDM was composed of two molecules of monoenoic or dienoic alpha-mycolic acids with a carbon chain length ranging from C44 to C48 centering at C46. To detect the antibody, an enzyme-linked immunosorbent assay (ELISA) system was employed using plastic plates coated with TDM. The antibody reacted against the TDM of R. ruber. The antibody was reactive in similar fashion against glycosyl monomycolates differing in the carbohydrate moiety, such as that of glucose mycolate (GM) and mannose mycolate (MM), obtained from R. ruber. Moreover, the antibody reacted against mycolic acid methyl ester itself when it was used as the antigen in ELISA, and trehalose did not absorb the antibody to TDM or inhibit the reaction. These results indicate that the epitope of TDM recognized by the antibody is mycolic acid, an extremely hydrophobic part of the molecule. Next, we prepared monoclonal anti-TDM antibody (moAb) in mice myeloma cells to examine its biological activities and the role of humoral immunity in mycobacterial infection. MoAb reacted against the TDM, glycosyl mycolate, and mycolic acid methyl ester in ELISA in the same manner as our polyclonal antibody did. The administration of moAb suppressed granuloma formation in the lungs, spleen, and liver induced by TDM and inhibited the production of interleukin-1 (IL-1) and chemotactic factor, which is reported to precede granuloma formation.

Absorption↗

PubMed1999

Atrial ectopy originating from the posteroinferior atrium during radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia.

Atrial ectopy sometimes appears during RF ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia (AVNRT). However, its origin, characteristics, and significance are still unclear. To examine these issues, we analyzed 67 consecutive patients with AVNRT (60 with slow-fast AVNRT and 7 with fast-slow AVNRT), which was successfully eliminated by RF ablation to the sites with a slow potential in 63 patients and with the earliest activations of retrograde slow pathway conduction in 4 patients. During successful RF ablation, junctional ectopy with the activation sequence showing H-A-V at the His-bundle region appeared in 52 patients (group A) and atrial ectopy with negative P waves in the inferior leads preceding the QRS and the activation sequence showing A-H-V at the His-bundle region appeared in 15 patients (group B). Atrial ectopy was associated with (10 patients) or without junctional ectopy (5 patients). Before RF ablation, retrograde slow pathway conduction induced during ventricular burst and/or extrastimulus pacing was more frequently demonstrated in group B than in group A (9/15 [60%] vs 1/52 [2%], P < 0.001). Successful ablation site in group A was distributed between the His-bundle region and coronary sinus ostium, while that in group B was confined mostly to the site anterior to the coronary sinus ostium. In group B, atrial ectopy also appeared in 21% of the unsuccessful RF ablations. In conclusion, atrial ectopy is relatively common during slow pathway ablation and observed in 8% of RF applications overall and 22% of RF applications that successfully eliminated inducible AVNRT. Atrial ectopy appears to be closely related to successful slow pathway ablation among patients with manifest retrograde slow pathway function.

Adult↗

PubMed1999

Production and partial characterization of anti-cord factor (trehalose-6,6'-dimycolate) IgG antibody in rabbits recognizing mycolic acid subclasses of Mycobacterium tuberculosis or Mycobacterium avium.

An ELISA with cord factor (trehalose-6,6'-dimycolate) is useful for the serodiagnosis of tuberculosis. To clarify the exact antigenic epitope in cord factor, recognized by a rabbit anti-cord factor IgG antibody, and to ascertain the most sensitive and specific diagnostic test antigen, rabbits were immunized with two kinds of cord factors isolated from Mycobacterium tuberculosis or Mycobacterium avium and the reactivities of the sera were tested against cord factors or the component mycolic acid methyl esters by ELISA. The serum from rabbits immunized with M. tuberculosis cord factor was highly reactive against M. tuberculosis cord factor, but less reactive against M. avium cord factor. In contrast, the serum from rabbits immunized with M. avium cord factor was highly reactive against M. avium cord factor but less reactive against M. tuberculosis cord factor. Moreover, the serum from rabbits immunized with M. tuberculosis cord factor reacted against mycolic acid methyl esters, especially methoxy mycolic acid methyl ester. On the other hand, the serum from rabbits immunized with M. tuberculosis cord factor was less reactive against trehalose-6-monomycolate and not reactive against sulfolipid (2,3,6,6'-tetraacyl trehalose 2'-sulfate). From these results, it was concluded that the anti-cord factor IgG antibody, produced experimentally in rabbits, recognized the differences in the cord factor structures, i.e. the hydrophobic moiety rather than the carbohydrate moiety. It was also noted that the serum from rabbits immunized with M. tuberculosis cord factor was highly reactive against methoxy mycolic acid as an epitope. This paper is the first to describe how the anti-cord factor IgG antibody can recognize the mycolic acid subclasses, which differ according to the species of mycobacteria.

Animals↗

PubMed1999

[Bacteriological studies of traveller's diarrhoea (6). Analysis of enteropathogenic bacteria at Kansai Airport Quarantine Station from September 4th, 1994 through December 1996].

During the period of investigation from Sept. 4, 1994 to Dec, 1996, a total of 11,446,534 overseas travellers were quarantined at Kansai Airport Quarantine Station, and 22,187 voluntarily reported of episodes suffering from diarrhoea. Bacteriological examination of the stools a total of 9,299 individuals' was performed, and the following results were obtained. 1) Various enteropathogenic bacteria were isolated from 33.3% of the stools examined. Bacterial species isolated were as follows: Plesiomonas shigelloides, 2,066 cases (66.7%); Vibrio parahaemolyticus, 358 cases (11.6%); Aeromonas sobria, 360 cases (11.6%); Shigella spp., 291 cases (9.4%); Salmonella spp., 183 cases (5.9%); A. hydrophila, 126 cases (4.1%); and V. cholerae non-O1, 121 cases (3.9%). However, ETEC was not done with an object of test. 2) In 502 cases (16.2%), plural enteropathogenic bacteria were isolated from single patient, suggesting high frequency of a mixed infections. 3) From Feb. to Mar. 1995, thirteen cases cholera were found from patients who had travelled to Bali, Indonesia. Cases with enteropathogenic bacteria other than V. cholerae O1 were found without any seasonal variation. 4) The major regions where the travellers were infected with the pathogens are as follows: Vibrio spp., were from only Asia; Shigella, widely distributed but especially in India and Indonesia; P. shigelloides and Salmonella, widely distributed. 5) Among the Shigella strains, S. sonnei were isolated the most, followed by S. flexneri, S. boydii and S. dysenteriae. A strain of S. boydii provisional serovar E 16553 was isolated from a patient infected in India. 6) Among the Salmonella serovars, Salmonella Enteritidis was isolated the most frequently (49 cases, 25.7%). 7) 265 (89.2%) of 297 Shigella strains, 52 (27.2%) of 19] Salmonella strains, and 19 (95.0%) of 20 V. cholerae O1 were resistant to one or more drugs tested (SM. CP. TC. KM. ABPC. NA. OFLX). 8) All of the 20 V. cholerae O1 strains were Ogawa, E1 Tor. All of them were toxigenic strains. 9) The most frequently isolated serovar of V. parahaemolyticus was O3: K6. 89.8% of all V. parahaemolyticus strains were positive for thermostable direct hemolysin (TDH) gene, and 14.6% of them were positive for TDH-related hemolysin (TRH) gene by DNA-probe or PCR method.

Asia, Southeastern↗

PubMed1999

Analysis of receptor for Vibrio cholerae El tor hemolysin with a monoclonal antibody that recognizes glycophorin B of human erythrocyte membrane.

El Tor hemolysin (ETH), a pore-forming toxin secreted by Vibrio cholerae O1 biotype El Tor and most Vibrio cholerae non-O1 isolates, is able to lyse erythrocytes and other mammalian cells. To study the receptor for this toxin or the related molecule(s) on erythrocyte, we first isolated a monoclonal antibody, B1, against human erythrocyte membrane, which not only blocks the binding of ETH to human erythrocyte but also inhibits the hemolytic activity of ETH. Biochemical characterization and immunoblotting revealed that this antibody recognized an epitope on the extracellular domain of glycophorin B, a sialoglycoprotein of erythrocyte membrane. Erythrocytes lacking glycophorin B but not glycophorin A were less sensitive to the toxin than were normal human erythrocytes. These results indicate that glycophorin B is a receptor for ETH or at least an associated molecule of the receptor for ETH on human erythrocytes.

Antibodies, Monoclonal↗

PubMed1999

Induction of prophages of enterohemorrhagic Escherichia coli O157:H7 with norfloxacin.

Norfloxacin (NFLX) caused induction of prophages VT1 and VT2 of enterohemorrhagic Escherichia coli O157 at subinhibitory concentrations. In time course experiments, we observed the following sequential events: upon induction, the phage genomes underwent multiplication; the amount of stx genes increased; and subsequently, large quantities of toxins VT1 and VT2 were produced. Further studies showed that the molecular mechanism of prophage induction is closely related to the RecA system since the prophage VT2 was not induced with NFLX in a recA mutant strain.

Coliphages↗