Biomedical subjects

T Itoh

Publications and source records attributed to T Itoh.

At least 379 records · Page 21Linked to original sources

PubMed1998

Prevalence of verotoxin-producing Escherichia coli harbored in the intestine of cattle in Japan.

The production of verotoxin was examined in 2152 Escherichia coli isolates from 387 cattle in Japan from 1992 to 1994. The toxin was detected in 263 isolates from 94 cattle (detection rate: 24.3%). Verotoxin-producing E. coli (VTEC) was isolated from the cattle in 15 out of 17 prefectures, and the strains were divided into 33 serotypes. E. coli O157:H7 was isolated from 7 out of 387 cattle (detection rate: 1.8%) in four prefectures. These results suggest that VTEC is widely distributed in Japan and include a wide variety of serotypes.

Animals↗

PubMed1998

Reduced angiogenesis and tumor progression in gelatinase A-deficient mice.

Matrix proteolysis is thought to play a crucial role in several stages of tumor progression, including angiogenesis, and the invasion and metastasis of tumor cells. We investigated the specific role of gelatinase A (matrix metalloproteinase 2) on these events using gelatinase A-deficient mice. In these mice, tumor-induced angiogenesis was suppressed according to dorsal air sac assay. When B16-BL6 melanoma cells or Lewis lung carcinoma cells were implanted intradermally, the tumor volumes at 3 weeks after implantation in the gelatinase A-deficient mice decreased by 39% for B16-BL6 melanoma and by 24% for Lewis lung carcinoma (P < 0.03 for each tumor). The number of lung colonies of i.v. injections fell by 54% for B16-BL6 melanoma and 77% for Lewis lung carcinoma (P < 0.014 and P < 0.0015, respectively). These results indicated that host-derived gelatinase A plays an important role in angiogenesis and tumor progression, suggesting the usefulness of gelatinase A inhibitors for anticancer chemotherapy.

Animals↗

PubMed1998

Identification of a novel apoptosis-inducing factor derived from leukemic cells: endothelial interleukin-8, but not monocyte-derived, induces apoptosis in leukemic cells.

The human myelogenous leukemia cell line HL-60, treated with phorbol 12, 13-dibutyrate (PDBu), produces apoptosis-inducing factors (AIFs) in leukemic cells. We have purified AIF against leukemic cell line K562 as target cells, and N-terminal amino acid sequencing analysis revealed that this purified protein is identical to endothelial cell-derived interleukin-8 ([(Ala)-IL-8]77). In Western blot analysis of supernatants of PDBu-treated HL-60 cells, only [(Ala)-IL-8]77 was detected. Moreover, recombinant human [(Ala)-IL-8]77 induced apoptosis in leukemic cell lines such as K562, HL-60, KG-1, U937, THP-1 and Jurkat, but monocyte-derived IL-8 ([(Ser)-IL-8]72) did not. Therefore [(Ala)-IL-8]77 plays an important role in inducing apoptosis against leukemic cells and may lead to a new therapy for leukemia.

Apoptosis↗

PubMed1998

The histone binding protein nucleoplasmin does not facilitate binding of transcription factor IIIA to nucleosomal Xenopus laevis 5S rRNA genes.

In an attempt to understand the mechanism by which transcription factors compete with histone octamers for cognate binding sites in chromatin, the effect of the histone binding protein nucleoplasmin on the binding of TFIIIA to nucleosomal 5S rRNA genes was tested. In this study, it was shown that, despite the previously reported nucleosome remodeling ability of nucleoplasmin, the binding of TFIIIA to nucleosomal DNA cannot be facilitated by this protein. Furthermore, it was demonstrated that nucleoplasmin cannot overcome nucleosome mediated repression of transcription of reconstituted 5S rRNA genes. In contrast to earlier work, this study used a homologous system composed of the 5S rRNA gene, nucleoplasmin, and TFIIIA from Xenopus laevis.

Animals↗

PubMed1998

Joint fluid from patients with failed total hip arthroplasty stimulates pit formation by mouse osteoclasts on dentin slices.

Periprosthetic bone resorption has been implicated in the failure of total joint arthroplasty. Osteolysis is reported to be associated with bone resorption induced by bone-resorbing cytokines, which are released from macrophages and fibroblasts in periprosthetic tissues after stimulation by wear debris generated in the joint cavity. Recent reports have suggested the concept of the effective joint space, which includes all periprosthetic regions that are accessible to joint fluid and wear debris. In this study, we examined the levels of interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), and tartrate-resistant acid phosphatase (TRAP) in joint fluid after failed total hip arthroplasty (THA) with osteolysis and investigated whether the joint fluid could activate osteoclastic bone resorption using unfractionated mouse bone cells cultured on dentin slices. Histochemical analysis showed the presence of more TRAP-positive cells in synovial capsules from failed THA patients when compared with osteoarthritis (OA) patients (controls). The levels of IL-6, sIL-6R, and TRAP in joint fluid from failed THA patients were significantly higher than in OA patients. Mouse osteoclasts cultured on dentin slices with joint fluid from failed THA patients with osteolysis produced a significant increase of pit area, whereas cells cultured with joint fluid from OA patients did not. Interestingly, osteoclastic bone resorption on dentin slices was significantly correlated with TRAP activity in joint fluid (p < 0.0001). These results suggest that joint fluid containing bone-resorbing cytokines is produced by synovial capsules in failed THA patients with osteolysis and may activate osteoclasts around the prosthesis in combination with those produced by interface tissues, thus contributing to periprosthetic bone resorption.

Acid Phosphatase↗

PubMed1998

Lack of renal secretion of carbenicillin in rats: poor affinity to the organic anion transporter at renal brush border membrane.

The renal secretion of carbenicillin (CBPC) was studied in rats. The results obtained in the in vivo study indicated very poor renal secretion of CBPC in rats, which was entirely different from those observed in humans and rabbits. In humans and rabbits, significant and stereoselective renal secretion of CBPC was observed in vivo. In order to verify the poor renal secretion of CBPC in rats, the transport characteristics of the organic anion transporters were studied in vitro using basolateral and brush border membrane vesicles. Transport of p-aminohippuric acid (PAH) into the basolateral membrane vesicles (BLMVs) was inhibited by CBPC, indicating that the organic anion transporter located at the BLM may have affinity to CBPC. In contrast, the transport of PAH into the brush border membrane vesicles (BBMVs) was not inhibited by CBPC, suggesting that the organic anion transporter located at the BBM may not have affinity to CBPC. Similar results were obtained for sulbenicillin (SBPC). Since CBPC and SBPC exist as di-anions at physiological pH, the organic anion transporter located at the rat renal BBM may not exhibit affinity to water-soluble di-anions, which in turn will result in poor renal secretion of these compounds.

Animals↗

PubMed1998

Stereoselective renal secretion of carbenicillin in rabbits: role of the organic anion transporter at the renal brush border membrane.

Stereoselectivity in the renal secretion of carbenicillin (CBPC) was studied in rabbits. Significant renal secretion of CBPC was observed in vivo, with the secretion of the S-epimer being greater than that of the R-epimer. Stereoselective transport of CBPC was further studied in vitro using basolateral and brush border membrane vesicles prepared from rabbit kidneys. The transport of CBPC by the organic anion transporter into the basolateral membrane vesicles (BLMV) was not stereoselective. In contrast, a distinct stereoselectivity was observed in the transport of CBPC by the organic anion transporter into the brush border membrane vesicles (BBMV), with the transport of the S-epimer being more favorable. Significant epimer-epimer interactions were also observed in the transport into BBMV. The stereoselectivity of the transport of CBPC was calculated from the kinetic parameters with consideration of epimer-epimer interactions and was similar to that observed in vivo. It was concluded that the observed stereoselectivity in the renal secretion of CBPC in vivo reflected that of transport via the organic anion transporter located at the brush border membrane.

Animals↗

PubMed1998

Relationship between Joint National Committee-VI classification of hypertension and ambulatory blood pressure in patients with hypertension diagnosed by casual blood pressure.

BACKGROUND: White-coat hypertension has been diagnosed arbitrarily based on different criteria. In 1997, the Joint National Committee-VI (JNC-VI) reported a new classification of hypertension and strongly emphasized the importance of ambulatory blood pressure (ABP) monitoring. The report pronounced normal ABP values for the first time. HYPOTHESIS: The study's aim was to clarify the relationship between casual blood pressure (BP) and ABP of patients with essential hypertension in each stage of JNC-VI classification, and the prevalence of white-coat hypertension diagnosed by using JNC-VI normal ABP criteria. METHODS: Ambulatory blood pressure was monitored non-invasively in 232 patients with essential hypertension whose casual BP was > or = 140/90 mmHg. The patients were classified according to JNC-VI classification, and their casual BP was compared with ABP. The criterion of white-coat hypertension was defined as casual BP > or = 140/90 mmHg with normal ABP according to JNC-VI criteria (< 135/85 during daytime and < 120/75 during nighttime). RESULTS: Mean ABP increased as the stage advanced, and the differences between casual BP and ABP also increased. There were considerable overlaps in the distribution of ABP among stages. The prevalence of white-coat hypertension was 13% overall: 30% of the patients with isolated systolic hypertension, 19% of those in stage 1, 10% in stage 2, and 4% in stage 3. CONCLUSIONS: Classification of hypertension based on casual BP may not always correspond in severity to that based on ABP. Ambulatory blood pressure monitoring recommended by JNC-VI is very useful for the evaluation of hypertension to differentiate white-coat hypertension from true hypertension.

Adult↗

PubMed1998

Expression of pancreatitis-associated protein (PAP) mRNA in gastrointestinal cancers.

CONCLUSION: Pancreatitis-associated protein (PAP) mRNA is expressed in some cases of gastric and colorectal cancers resulting from an ectopic expression in dedifferentiated cancer cells. BACKGROUND: The PAP gene is identical to the hepatoma-intestine-pancreas (HIP) gene, which is expressed in hepatoma. Expression in cancer might be another characteristic of PAP. METHODS: Fresh surgical specimens of 100 gastrointestinal cancers, 14 benign digestive diseases, and six normal organs were studied with nonisotopic in situ hybridization (ISH) using biotin-labeled cDNA probe. RESULTS: PAP mRNA was detected in 10% (6/60) of gastric cancers, 21.4% (6/28) of colorectal cancers, 20.0% (1/5) of pancreatic cancers and 0% of biliary tract (three), esophageal (one), and hepatocellular cancers (three). Reverse transcription-polymerase chain reaction (RT-PCR) detected PAP mRNA in these ISH-positive cases. PAP mRNA was not detected in noncancerous portions, benign disease tissues, or normal organs except for the small intestine. There was no relationship between PAP mRNA expression and any clinicopathological factors.

Acute-Phase Proteins↗

PubMed1998

[Initial clinical experiences of the ABIOMED BVS SYSTEM 5000 in Japan].

The initial clinical experience of the ABIOMED BVS SYSTEM 5000 in Japan is reported. The system is a paracorporeal pulsatile assist device intended for temporary ventricular support. It consists of a pneumatic drive console, a blood pump, and the atrial and arterial cannulas. The pump is of a dual chamber design, with the upper chamber as a passive, gravity filled resevoir and the lower chamber as a pumping chamber. Since the system is designed to be simple, safe and automatically controlled, no additional personnel is required to control perfusion. This report describes our initial clinical experiences with the ABIOMED BVS SYSTEM 5000 in Japan. This device was used in three patients with post cardiotomy cardiogenic shock and fulminant myocarditis. The first patient developed acute occlusion of left main coronary artery who required emergent surgical revascularization following PTCA and stent implantation. He couldn't wean from CPB and required the insertion of an LVAD. The second case suffered from a cardiac arrest after CABG and could not be resuscitated. The ABIOMED BVS 5000 was inserted and the patient successfully weaned from support. The third patient developed fulminant myocarditis and was supported with the system for 269 hours and was successfully weaned after near complete myocardial recovery. Our initial experience with the ABIOMED BVS SYSTEM 5000 indicates that the system can provide complete cardiac support allowing full recovery from a cardiac variety of causes of dysfunction. The device has the potential to improve the survival rate of patients with severe acute recoverable myocardial damage. It is expected that this device can be a viable tool for treatment of intractable heart diseases.

Adult↗

PubMed1998

Occurrence of introns in the 16S rRNA genes of members of the genus Thermoproteus.

Multiple introns were detected in the 16S rRNA gene of newly isolated Thermoproteus species strains IC-033 and IC-061 and Thermoproteus neutrophilus JCM 9278. In the 16S rRNA gene of strain IC-033, five introns of 627, 762, 636, 33, and 682 bp existed after positions 548, 781, 1092, 1205, and 1213 (according to the Escherichia coli numbering system), respectively. Likewise, strain IC-061 possessed 764-, 32-, and 688-bp introns after positions 781, 1205, and 1213, respectively; and T. neutrophilus JCM 9278 had 34- and 663-bp introns after positions 1205 and 1213, respectively. All the introns carried the putative intron core structures consisting of a bulge-helix-bulge motif and a long stable stem. The large introns carried open reading frames containing the LAGLI-DADG-like motifs in their terminal inserts; however, three out of four large introns of strain IC-033 seemed to incur frameshift mutations. Occurrence of introns at the same insertion sites in the three strains would allow tracing of the evolutionary movements of these introns.

Evolution, Molecular↗

PubMed1998

Isolation and characterization of Helicobacter species from the stomach of the house musk shrew (Suncus murinus) with chronic gastritis.

A Gram-negative, motile bacterium with bipolar sheathed flagella (one at each end) was isolated from the stomach of house musk shrews (Suncus murinus) with chronic gastritis. The isolates grew at 37 degrees C under microaerophilic conditions, but not under aerobic conditions; rapidly hydrolyzed urea; were catalase, oxidase, alkaline phosphatase, and arginine aminopeptidase positive; reduced nitrate to nitrite; and were resistant to cephalothin and nalidixic acid, but sensitive to tetracycline, erythromycin, and chloramphenicol. This bacterium was found on gastric epithelial cells by electron microscopy. In addition, a coccoid form of the bacteria was found in vacuoles formed in the epithelial cells of some of the house musk shrews tested. These results, including 16S rRNA gene sequence analysis, strongly suggested that this bacterium should be classified as a novel Helicobacter species. It is proposed that this bacterium should be called "Helicobacter suncus."

Animals↗

PubMed1998

Expression of low-affinity neurotrophin receptor p75NTR in the peripheral nervous system of human neuropathies.

Expression of low-affinity neurotrophin receptor (p75NTR) was immunohistochemically examined in the peripheral nerve trunks, dorsal root ganglia, sympathetic nerve ganglia and spinal cords in various human neurological diseases manifesting peripheral neuropathies. p75NTR was expressed in the nerves with axonal degeneration, and was also prominent in the nerves with newly regenerating axons. In contrast, axonal pathology tended to reduce the expression of p75NTR in the neuronal perikarya of the dorsal root ganglion and sympathetic nerve ganglion neurons. In the ventral and lateral horn cells, the p75NTR immunoreactivity was not detected in the normal and diseased nerves except for amyloid polyneuropathy. These p75NTR expressions in the diseased human peripheral nervous tissues would be regulated by an underlying pathology-related process, and could play a role in peripheral nerve repair.

Aged↗

PubMed1998

Genomic organization and mutational analysis of HERG, a gene responsible for familial long QT syndrome.

Familial long QT syndrome (LQTS) is characterized by prolonged ventricular repolarization. Clinical symptoms include recurrent syncopal attacks, and sudden death may occur as a result of ventricular tachyarrhythmias. Three genes responsible for this syndrome (KVLQT1, HERG, and SCN5A) have been identified so far, and mutations have been reported on the basis of partially characterized genomic organization. To optimize the search for HERG mutations, we have determined the genomic structure of HERG and investigated mutations in LQTS families. Human genomic clones containing the HERG gene were isolated from a human genomic library by using reverse-transcribed polymerase chain reaction (RT-PCR) products from this gene as probes. We determined exon/intron boundaries and flanking intronic sequences by using primers synthesized on the basis of the HERG cDNA sequence available in the DNA database. HERG was shown to consist of 15 exons spanning approximately 19 kb on chromosome 7q35. Subsequently, we synthesized oligonucleotide primers to cover the entire coding region and searched for mutations in 36 Japanese LQTS families. When genomic DNA from each proband was examined by the PCR/single-strand conformation polymorphism technique followed by direct DNA sequencing, five novel mutations were detected. Each mutation was present in affected relatives of the respective proband. This work should increase the efficiency of screening mutations associated with HERG.

Amino Acid Sequence↗

PubMed1998

Genomic organization and mutational analysis of KVLQT1, a gene responsible for familial long QT syndrome.

To elucidate the role of the KVLQT1 gene in the pathogenesis of long QT syndrome (LQTS), we have established a screening system for detecting KVLQT1 mutations by the polymerase chain reaction-single strand conformation polymorphism technique (PCR-SSCP). We first determined exon/intron boundaries and flanking intronic sequences, and found that the KVLQT1 gene consists of 17 coding exons. Subsequently, we synthesized oligonucleotide primers to cover the coding region and the flanking intronic sequences, and searched for mutations in 31 Japanese LQTS families. When genomic DNA from each proband was examined by PCR-SSCP followed by direct DNA sequencing, mutations were detected in five families; two independent families carried the same mutation and three of the four were novel. Each mutation was present in affected relatives of the respective proband. This work will enable us to search more thoroughly for LQTS mutations associated with KVLQT1, and eventually will help us in finding genotype/phenotype relationships.

DNA Mutational Analysis↗

PubMed1998

Electrogastrographic power ratio in humans is not related to changes in antrum-skin distance but to antral motility.

It is not clear whether the power increase in electrogastrography (EGG) after meal or water ingestion reflects increases in gastric motility or gastric distension bringing the stomach closer to the electrodes on the abdominal skin surface. We recorded EGG and real-time ultrasonography simultaneously before and after 150-ml water ingestion in 17 healthy volunteers. We calculated gastric power, by spectral analysis of EGG by the maximum entropy method, for 400 s before and after water ingestion, and calculated their ratio (power ratio). We calculated, using sonography, the number of antral contractions before and after water ingestion, the motility index after water ingestion, the distance between the antrum and the abdominal skin surface before and after water ingestion, and the ratio of these distances (distance ratio). The number of contractions was positively correlated with gastric power before water ingestion, and the antrum-skin distance was negatively correlated with gastric power both before and after water ingestion. The motility index after water ingestion was positively correlated with both gastric power after water ingestion (Spearman's rank correlation r = 0.492; P = 0.0498) and the power ratio (r = 0.615; P = 0.0141). There was no correlation between the distance ratio and the power ratio. These results suggest that the power increase in EGG induced by water ingestion does not reflect the approach of the antrum to the abdominal surface, but rather, reflects antral motility after water ingestion.

Adult↗

PubMed1998

Urgent total arch graft replacement in an elderly patient with acute type A dissection: report of a case.

There are many controversies regarding the treatment of acute aortic dissections. We herein present the case of an elderly patient over 80 years of age who underwent an urgent total arch graft replacement for a Stanford type A acute thrombosed aortic dissection complicating cardiac tamponade. An 81-year-old woman with chest discomfort and shock that developed 1 day earlier was transferred to our hospital by ambulance. A plain chest computed tomogram, aortogram, and an echocardiography revealed mild pericardial effusion and an ascending aortic aneurysm measuring 5 cm in diameter, but no evidence of an intimal tear in the ascending aorta and aortic arch. At operation, after the bloody pericardial effusion had been decompressed, her blood pressure was elevated and a type A acute thrombosed aortic dissection with the intimal tear in the aortic arch was confirmed, with a false channel filled with clotted blood. She underwent a successful emergency total arch graft replacement using selective cerebral perfusion and open distal anastomosis. The postoperative course was uneventful and the false lumen was closed. We thus conclude that early graft replacement should be performed on patients with Stanford type A acute thrombosed aortic dissection complicating cardiac tamponade, even in elderly patients over 80 years old.

Acute Disease↗

PubMed1998

Reversibility of cardiac dysfunction after valve replacement in elderly patients with severe aortic stenosis.

BACKGROUND: The role of aortic valve replacement for aortic stenosis has not been fully defined in terms of the postoperative reversibility of cardiac dysfunction and pulmonary hypertension in elderly patients. METHODS: Cardiac function, assessed by radioisotope ventriculography and catheterization data, was evaluated before and after operation, and their results were compared between preoperative and postoperative data in each group of younger patients (<69 years, group I, n = 29) and elderly patients (> or =70 years, group II, n = 21). RESULTS: One month postoperatively the peak ejection rate determined by radioisotope ventriculography improved significantly in comparison with the preoperative value in elderly patients (preoperatively, 228 +/- 38 versus postoperatively, 319 +/- 116% end-diastolic volume per second, p < 0.05), although their preoperative peak ejection rate was severely depressed. The postoperative peak filling rate of the elderly group was not completely reversible to almost normal value, whereas that of the younger group was completely reversible. Early diastolic peak filling rate (one-third peak filling rate) was not reversible in both two groups. Pulmonary hypertension in the elderly patients was reversible to postoperative almost normal pulmonary artery pressure despite the severity of aortic stenosis (systolic pulmonary artery pressure preoperatively, 37 +/- 16 mm Hg versus postoperatively, 25 +/- 5 mm Hg, p < 0.02; diastolic pulmonary artery pressure preoperatively, 15 +/- 6 mm Hg versus postoperatively, 10 +/- 4 mm Hg, p < 0.05). CONCLUSIONS: Both cardiac dysfunction, reflected by reduction of peak ejection rate, and pulmonary hypertension in elderly patients with severe aortic stenosis were reversed, reaching almost normal values 1 month after operation.

Aged↗