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T Okitsu

Publications and source records attributed to T Okitsu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Facial nerve palsy: evaluation by contrast-enhanced MR imaging.

AIM: The purpose of this study was to investigate the value of contrast-enhanced magnetic resonance (MR) imaging in patients with peripheral facial nerve palsy. MATERIALS AND METHODS: MR imaging was performed in 147 patients with facial nerve palsy, using a 1.0 T unit. All of 147 patients were evaluated by contrast-enhanced MR imaging and the pattern of enhancement was compared with that in 300 control subjects evaluated for suspected acoustic neurinoma. RESULTS: The intrameatal and labyrinthine segments of the normal facial nerve did not show enhancement, whereas enhancement of the distal intrameatal segment and the labyrinthine segment was respectively found in 67% and 43% of patients with Bell's palsy. The geniculate ganglion or the tympanic-mastoid segment was enhanced in 21% of normal controls versus 91% of patients with Bell's palsy. Abnormal enhancement of the non-paralyzed facial nerve was found in a patient with bilateral temporal bone fracture. CONCLUSION: Enhancement of the distal intrameatal and labyrinthine segments is specific for facial nerve palsy. Contrast-enhanced MR imaging can reveal inflammatory facial nerve lesions and traumatic nerve injury, including clinically silent damage in trauma.

Adolescent↗
PubMed2001

Identification of shiga toxin-producing Escherichia coli possessing insertionally inactivated Shiga toxin gene.

We have investigated the Shiga toxin genes of Shiga toxin-producing Escherichia coli (STEC) strains, using polymerase chain reaction (PCR) amplifying the full lengths of these genes. As a result, we found the Shiga toxin 2 gene which was insertionally inactivated by an insertion sequence (IS). This IS element was identical to IS1203v which has been also found in inactivated Shiga toxin 2 genes, and was inserted at the same site as in the previous paper. On the other hand, both Shiga toxin 2 genes were different (98.3% identity). These suggested that IS1203v independently inserted into each Shiga toxin 2 genes, and STEC strains possessing the insertionally inactivated Shiga toxin genes are most likely to have a wide distribution. Amplification of the full length of the Shiga toxin gene is one of the effective methods to detect the gene no matter where the IS element is included, i.e., the insertion can be reflected in the size of amplicon.

Animals↗
PubMed2001

Spontaneous reactivation of Shiga toxins in Escherichia coli O157:H7 cells caused by transposon excision.

IS1203v is an insertion sequence which has been found in inactivated Shiga toxin 2 genes (stx2) of Escherichia coli O157:H7. Using PCR amplification, we detected the wild-type stx2 genes in colonies of E. coli O157:H7 which possessed stx2 genes inactivated by insertion of IS1203v. This suggests that IS1203v is excised from the inactivated stx2 genes in E. coli O157:H7. We isolated the cells possessing the wild-type stx2 genes, and confirmed Stx2 productivities by reversed passive latex agglutination. We also analyzed the frequency of the appearance of the Stx2-producing cells using a quantitative PCR method. As a result, the frequency was 3.00 x 10(-6) with culturing for 24 h at 37 degrees C, and this increased to 8.83 x 10(-5) when E. coli O157:H7 possessing the inactivated stx2 genes was transformed by an expression plasmid harboring the IS1203v transposase. These results showed that some Stx2-nonproducing E. coli O157:H7 strains could be spontaneously changed into Stx2-producing cells.

Journal Article↗
PubMed2001

Rapidly functional immobilization of immortalized human hepatocytes using cell adhesive GRGDS peptide-carrying cellulose microspheres.

With the development of biotechnology, hepatic support by a hybrid artificial liver (HAL) using hepatocytes has been given much attention. Because the availability of human livers is limited, we have established a tightly regulated immortal human hepatocyte cell line, NKNT-3, for developing HAL. Because high-density cell culture allows the compactness of the HAL device and its easy use under emergency circumstances, we have developed cell adhesive GRGDS peptide-containing cellulose microspheres (GRGDS/CMS). The GRGDS/CMS efficiently immobilized NKNT-3 cells within 24 h in a stirred suspension culture. Electron microscopic examinations demonstrated glycogen granules and well-developed endoplasmic reticulum and mitochondria in NKNT-3 cells attached to the GRGDS/CMS. The cells showed ammonia clearance activity, whereas HepG2-transformed human liver cells did not remove the loaded ammonia. An efficient adenoviral delivery of the lacZ reporter gene was performed in GRGDS/CMS-immobilized NKNT-3 cells. In this study we present rapid immobilization of NKNT-3 immortal human hepatocytes using cellulose microspheres carrying GRGDS peptides. These microspheres satisfied immediate preparation of NKNT-3 cells in sufficient quantity and of adequate quality.

Ammonia↗
PubMed2001

Recurrent autoimmunity accelerates destruction of minor and major histoincompatible islet grafts in nonobese diabetic (NOD) mice.

Recurrent autoimmunity destroys nonobese diabetic (NOD) islet isografts, but whether recurrent autoimmunity contributes to islet graft destruction in immunocompetent allogeneic recipients is unknown. In the NOD, a single dose of streptozocin prevents or delays primary autoimmunity, allowing the detection of alloimmunity alone in chemically diabetic hosts (streptozocin-NOD) to be compared to the combined effects of autoimmunity and alloimmunity in spontaneously diabetic NODs (autoimmune-NOD). Islets were isolated from prediabetic NOD (H-2KdDb), nonobese resistant (NOR) (H-2KdDb), Balb/cByJ (H-2d) and B10.BR (H-2k) donors and transplanted to either the renal subcapsule or the intraportal site in autoimmune-NODs or streptozocin-NODs. MHC-matched NOR islets had in definite graft survival in streptozocin-NODs. However, NOR islets showed graft loss at 12.6 +/- 3.2 days in renal subcapsule and at 6.8 +/- 0.1 days in intraportal site of autoimmune-NODs. Partially MHC-matched Balb/cByJ islet grafts failed significantly sooner in autoimmune-NODs than in streptozocin-NODs (p < 0.005). Fully MHC-mismatched B10.BR islet grafts also failed sooner in autoimmune-NODs, but the difference did not reach significance (p < 0.06). Although the streptozocin-NOD was functionally tolerant of MHC-matched NOR islets, NOR islets transplanted into autoimmune-NODs failed sooner than NOD islets in both renal subcapsule (12.6 +/- 3.2 days vs. 26.4 +/- 10.5 days, p = 0.009) and intraportal sites (6.8 +/- 0.1 days vs. 11.5 +/- 1.7 days, p = 0.014). In the autoimmune-NODs, the intraportal site consistently showed shorter graft survival than the renal subcapsule site (NOD: p = 0.009, NOR: p = 0.014, Balb/cByJ: p = 0.008, B10.BR: p = 0.032). In conclusion, autoimmune processes facilitate the alloimmune response to minor and major histocompatibility antigens and accelerate graft destruction. The same autoimmune processes are more pronounced in the intraportal site.

Animals↗
PubMed2000

[Isolation of Aeromonas species from patients with sporadic diarrhea and characterization of Aeromonas hydrophila isolates].

A total of 16 strains of Aeromonas species were isolated from feces of 348 patients with sporadic diarrhea in western Kanagawa, Japan from 1996 to 1998. Of the 16 isolates, 7 were Aeromonas hydrophila, 1 was A. sobria and 8 were A. caviae. The strains of A. hydrophila were examined for hemolytic activities, hemolysin gene types and O-serogroups. Although all 7 strains of A. hydrophila showed hemolytic activities on sheep blood agar, in the test for hemolytic activities in culture supernatant, only 1 of the these strains showed no hemolytic activity against sheep erythrocytes. From the results of PCR assay, the tested strains of A. hydrophila were grouped into 2 hemolysin gene types of [ahh1 + ahh3 + aerA] (n = 6) and [ahh1 + aerA] (n = 1) both of which are recognized to be enteropathogenic. Five of the 7 strains of A. hydrophila belonged to serogroup O11. These results suggest that 7 strains of A. hydrophila isolates are recognized to be enteropathogenic strains and serogroup O11 is the major O-serogroup of enteropathogenic A. hydrophila in humans.

Aeromonas↗
PubMed1999

[Isolation of Shiga toxin-producing Escherichia coli O157:H7 from processed salmon roe associated with the outbreaks in Japan, 1998, and a molecular typing of the isolates by pulsed-field gel electrophoresis].

Shiga toxin-producing Escherichia coil (STEC) O157 were isolated from processed salmon roe which had been a suspected food item in sporadic infections which occurred in Japan in 1998. A total of 45 samples of the processed salmon roe were pre-enriched in trypticase soy broth (TSB) at 36 degrees C for 6 h and novobiocin-supplemented modified EC broth (mEC-NB) at 42 degrees C for 18 h. After the pre-enrichments, the cultures were examined for possible occurrence of STEC O157, using an immunomagnetic separation (IMS) method. From the examination, a total of 84 strains of STEC O157:H7 that were positive for both stx 1 and stx 2 genes were isolated. By applying the most-probable-number technique, it was estimated that the number of STEC O157 was in the range of 0.73-1.5 per 10 g of the processed salmon roe. Subsequent analysis of the isolates by a pulsed-field gel electrophoresis (PFGE) revealed a pattern commonly seen in 82 isolates and another pattern in two isolates. Clinical isolates from 7 patients also showed an identical pattern to those of the 82 isolates and one isolate from a patient showed the other pattern identical to those of the two isolates. The isolates were found to belong to the phage type 14.

DNA, Bacterial↗
PubMed1999

Additional O antigens of Vibrio fluvialis and Vibrio furnissii.

A total of 297 strains of Vibrio fluvialis and Vibrio furrnissii, which were collected from various countries for the past 15-year period of 1984-1998, were serogrouped. Of those examined, 239 strains of V. fluvialis and V. furnissii were classified into 29 known O serogroups; 9 strains were found to belong to R-form cultures, and the rest of the 49 strains could not be serogrouped. Of those serologically untypable strains, 26 novel O serogroups (O36 to O61) were established and added to our reference of the V. fluvialis and V. furnissii antigenic scheme. As all antisera against the O reference strains of the organisms contained some amount of antibody to the rough (R) antigen, all diagnostic O antisera were absorbed with the reference rough strain, V. fluvialis GF25.

Agglutination Tests↗
PubMed1998

Discontinuous total parenteral nutrition prevents postischemic mitochondrial dysfunction in rat liver.

Although discontinuous total parenteral nutrition (d-TPN) has recently been favored for clinical use over continuous total parenteral nutrition (c-TPN) to ameliorate liver dysfunction, mechanisms for the protection against postoperative liver dysfunction remain unknown. This study aimed to examine differences in mitochondrial function in d-TPN- and c-TPN-pretreated livers during ischemia-reperfusion. Rat livers pretreated with d-TPN or c-TPN were perfused with Krebs-Ringer buffer and were exposed to 25% low-flow hypoxia followed by reperfusion. Intrahepatic mitochondrial membrane potential (triangle up) and cell viability were assessed by dual-color digital microfluorography using rhodamine 123 (Rh123) and propidium iodide (PI), respectively. In response to hypoxia, livers pretreated with c-TPN, d-TPN, and an ordinary chow diet exhibited a significant triangle up reduction among the entire lobules. Upon reperfusion, the regional triangle up values further decreased in the c-TPN liver, whereas those in the d-TPN-treated or chow-treated livers displayed a rapid recovery toward the control levels. The severity of cell injury did not differ among the groups, showing that the reperfusion-induced triangle up drop in the c-TPN-pretreated liver is not a consequence of cell injury. Differences in the triangle up drop among the groups appear to occur irrespective of those in the glycogen storage, because the livers undergoing d-TPN display a marked triangle up recovery even when reperfused at the end of a fasted state. These results indicate that c-TPN, but not d-TPN, jeopardizes mitochondrial re-energization and suggest that a circadian pattern of the TPN serves as a potentially beneficial strategy to reduce the risk of postischemic mitochondrial dysfunction in the liver.

Animals↗
PubMed1997

Urea hydrolysis and suppressed production of thermostable direct hemolysin (TDH) by Vibrio parahaemolyticus associated with presence of TDH-related hemolysin genes.

A total of 18 strains of V. parahaemolyticus isolated from patients of past food poisoning cases occurring in Kanagawa Prefecture, Japan, were assayed for presence of the thermostable direct hemolysin (TDH) gene and the TDH-related hemolysin (TRH) genes (trh 1 and trh 2) with specific reference to their ability to hydrolyze urea and TDH production. A polymerase chain reaction assay revealed that all urea-hydrolyzing strains (9 strains) carried either trh 1 gene or trh 2 gene. The strains carrying the trh genes as well as the tdh gene produced TDH less by a factor of 4 to 16 than those carrying only the tdh gene, suggesting the expression of the tdh gene was suppressed by the presence of trh gene through a mechanism yet to be defined.

Bacterial Proteins↗
PubMed1997

[Distribution of serogroups of Vibrio cholerae non-O1 non-O139 with specific reference to their ability to produce cholera toxin, and addition of novel serogroups].

A total of 1898 strains of Vibrio cholerae non-O1 non-O139, which had been collected worldwide for the past 3 year period of 1994-1996, were serogrouped. The strains were also examined for presence of cholera toxin (CT) gene (ctx) and NAG-ST gene, and strains which carried to ctx were further analyzed for their ability to produce CT. In addition, attempts were made to establish novel serogroups for those serologically untypable strains. Of those examined, 1,774 strains of V. cholerae non-O1 non-O139 was classified into 128 known serogroups while 50 strains were found to belong to R type, and the rest of the 74 strains could not be serotyped. Distribution of the serogroups did not seem to correspond to either the strains geographic distribution or sources of isolation. Of those serologically untypable strains, 38 novel serogroups (O156-O193) were established and added to our reference of V. cholerae antigenic schema. It was also found that antisera raised against many V. cholerae strains included R antibodies. This indicates that any V. cholerae antisera for diagnostic purpose should be absorbed with the reference R strains, CA385, before use. There were luminescence producing strains among those sucrose and VP reaction negative strains. Subsequent DNA/DNA homology analysis revealed that they were identified as V. cholerae. This points to a possibility that strains tentatively identified as Vibrio mimicus by conventional biochemical tests may have included luminescent strains of V. cholerae. It is thus highly recommended that strains in question should be tested for the luminescence production in order to differentiate V. cholerae from V. mimicus. Of those 1989 strains examined, 37 strains (ca. 2%) were found to produce CT. Interestingly, CT producing strains were prevalent in serogroup O141; 10 strains out of 16 strains (63%) were positive for CT. The evidence calls for a caution to possible occurrence of cholera-like diarrhea caused by V. cholerae O141 in the future.

Cholera Toxin↗
PubMed1997

[Detection of the thermostable lipase gene (lipAH) in clinical isolates of Aeromonas hydrophila belonging to the major O serogroups O11, O16 and O34].

On the basis of DNA hybridization data and phenotypes, most pathogenic strains of Aeromonas hydrophila are grouped into hybridization group 1 (HG1). These pathogenic strains secret the theromostable lipase, and it's gene (lipAH) has been cloned and sequenced. The present study was performed to identify the pathogenic strains of A. hydrophila by the polymerase chain reaction (PCR) technique to detect the lipAH. Synthetic oligonucleotide primers (lipAH-ns-1 and -na-1) were used in the PCR. The PCR identified 80% of lipAH-positive strains, consisting of seven of the 11 O11 strains (64%), 13 of the 15 O16 strains (87%) and 25 of the 30 O34 strains (83%) in clinical isolates of A. hydrophila used in this study.

Aeromonas hydrophila↗
PubMed1997

[Isolation of enterohemorrhagic Escherichia coli (O157:H7) by an immunomagnetic separation method].

Three sporadic cases of enterohemorrhagic Escherichia coli (EHEC) O157 infection which occurred in Kanagawa in 1996 were investigated. In an attempt to determine sources of the infection, a novel method of immunomagnetic separation (IMS) was employed to isolate the bacterium from feces, foods, and other associated items. In the first case, strains of EHEC O157:H7 producing Vero toxin (VT) 2 were isolated from both feces of the patient and suspected food (cattle liver) kept at a restaurant, and the strains were found to be genotypically identical through an analysis of pulsed-field gel electrophoresis (PFGE). Subsequent investigation in the meat processing store, from which the above cattle liver had been retailed to the restaurants revealed that the store was contaminated with EHEC O157:H7 producing both VT1 and VT2. In the second case, a strain isolated from the patient was EHEC O157:H7 producing both VT1 and VT2 while strains isolated from the patient's family (without apparent symptom) and the suspected facility were O137:NM producing VT2. PFGE analysis indicated that the latter two strains were genotypically identical, suggesting that the facility thus contaminated with EHEC O157 caused the infection in question. In the third case, EHEC O157:NM producing VT2 was isolated from 4 out of 7 family members including the patient, and these strains were found to be genotypically identical by subsequent PFGE analysis. Source of the infection was, however, not determined due to lack of suspected food items. In this context, four slaughterhouses in Kanagawa Prefecture were investigated for presence of EHEC O157. As a result, strains of EHEC O157:H7 producing VT1 and VT2 were isolated from the contents of cattle's distal colon and surface of the skinned carcasses. Additional attempt was also made to determine a possibility of river water being contaminated with EHEC O157. The bacterium was, however, not isolated from water samples collected from 4 major rivers in the prefecture (at 10 collecting sites). Experiments were undertaken in order to evaluate the use of IMS in isolation of EHEC O157 from food items, with different pre-enrichment media and conditions. The results indicated that pre-enrichment by trypticase soy broth at 36 degrees C for 6 h followed by inoculating onto sorbitol MacConkey agar plate containing cefixime and tellurite was most appropriate to isolate EHEC O157 strains.

Adolescent↗
PubMed1997

[Studies of Vibrio cholerae O140 (serogroup Hakata) isolated from river water].

Strains of Vibrio cholerae O140, which were isolated from river (Hikichi River) water in Kanagawa, Japan, were studied for their biochemical characteristics and toxin genes, and analyzed by an amplified polymorphic DNA method in comparison with both clinical and environmental isolates of V. cholerae O140. Biochemical characteristics of 4 river isolates studied were found to be unanimous by conventional tests and a commercially available identification kit (Api 50 CH). The strains were also found to react positively with both cholera Inaba factor (C) and V. cholerae O140 specific factor (F). A total of 34 V. cholerae O140 strains including the 4 stains, a reference strains (487-95), 25 strains isolated from samples of river or sea water in Japan, 4 strains isolated from a patient and imported foods, was investigated by the PCR method for presence of ctx, zot, hlyA, and NAG-ST genes. It was found that all strains carried the hlyA gene but none of them carried either ctx, zot, or NAG-ST genes. V. cholerae O140 shared a common antigenic structure with pathogenic V. cholerae strains but its pathogenicity seems to be comparable to that of V. cholerae non-O1 non-O139. Subsequent RAPD analysis indicated that the strains can be divided into 9 groups. Four strains from the Hikichi River showed the same RAPD pattern. The results suggest that the analysis can be a useful epidemiological tool for V. cholerae O140, and that V. cholerae O140 persists in the Hikichi River throughout years.

Japan↗
PubMed1997

Rapid screening method for identification of cholera toxin-producing Vibrio cholerae O1 and O139.

A novel method of identifying cholera enterotoxin (CT)-producing Vibrio cholerae serogroups O1 and O139 was developed. The method uses degradation of NAD as a specific biochemical marker for the CT-producing strains. The substrate NAD at a concentration of 100 mumol/liter was markedly degraded when it was incubated at 37 degrees C for 2 h with the CT-producing stains at a final cell density equivalent to that of a twofold dilution of a McFarland no. 1 standard. NAD degradation was monitored by an enzyme-amplified color development assay. Subsequent tests conducted with a total of 119 strains of V. cholerae, including both clinical and environmental isolates, confirmed a significant correlation between NAD degradation and CT production for all V. cholerae strains belonging to serogroups O1 and O139. Since 2 of 11 non-O1, non-O139 V. cholerae strains not carrying the CT gene degraded NAD, serotyping of the strains prior to the test is recommended.

Bacterial Typing Techniques↗
PubMed1997

Middle ear inflation as a treatment for secretory otitis media in children.

Clinical evaluations of middle ear inflation for secretory otitis media (SOM) were performed with special emphasis on the influence of seasonal and aging factors. One hundred and forty-nine children between the ages of 3 and 9 years (227 ears) were all diagnosed as SOM by pneumatic-otoscopic findings, and type B tympanogram (TG) at 3 weeks or more after the onset of acute SOM or the initial observation of SOM. Middle ears were inflated by Politzer's method or by our modified method once or twice each week for 2 months. After inflation, TG displayed two different time sequences: one group changed to the A or C type immediately after inflating the ear one or more times, but usually returned gradually to the B type (TG-improved group): and the other group remained without any changes (TG-unchanged group) for the duration of this study. The healing rate in the TG-improved group was significantly higher than in the TG-unchanged group at the 2-month endpoint. The cure rate of SOM was significantly higher in spring than in autumn in the TG-unchanged group but not in the TG-improved group. There were almost no differences between the healing rates in the 3-5 and 6-9 year-old children. When a TG-unchanged ear is found in autumn during the 2-month inflation treatment, more careful and forcible treatments should be introduced later, especially to children between the ages of 3 and 9 years.

Child↗
PubMed1996

[Isolation and incidence of Vibrio cholerae from river water].

The prevalence of Vibrio cholerae contamination in river water derived from 20 sites of 18 rivers in Kanagawa, Japan, was investigated during a period from July to September, 1987, and from one of the 20 sites in August, 1988 and in February, 1989, V. cholerae non-O1 was found in all samples at concentrations of 0.9-->1,400 MPN/100 ml. Higher amounts of the organism were observed in the samples from estuaries. V. cholerae O1 was detected in samples collected in August, 1988 and in February, 1989 at concentrations of 150 MPN/100 ml and 1.5 MPN/100 ml, respectively. From 1989 to 1995, water samples were collected monthly from 10 sites of 10 rivers to detect V. cholerae. V. cholerae O1 and non-O1 were detected in 3.6% (30 of 840) and in 61.1% (513 of 840) in the water samples examined, respectively. Overall, V. cholerae was found in 62.9% (528 of 840). Both types, O1 and non-O1, of organisms were detected in 15 samples. These results indicated that river water was contaminated frequently with V. cholerae non-O1 and sporadically with V. cholerae O1 throughout the year. Only one strain of V. cholerae O1 out of 543 V. cholerae strains was found to be a producer of cholera toxin. During these studies, the selectivity of 3 media for V. cholerae O1 was evaluated, and PMT agar was found to be the best.

Japan↗