PubMed Health⌕ Search

Biomedical subjects

H Sekiguchi

Publications and source records attributed to H Sekiguchi.

At least 19 recordsLinked to original sources
PubMed2003

Pathogenicity and kinetics of virus propagation in swine infected with the cytopathogenic classical swine fever virus containing defective interfering particles.

To analyze the pathogenicity and in vivo kinetics of the cytopathogenic (cp) classical swine fever virus (CSFV) WB82 strain, which is composed of cp defective interfering (DI) particles and noncytopathogenic (noncp) helper virus (WB82/E(+) strain), WB82 and WB82/E(+) strains were administered separately to domestic pigs. After inoculation with either strain, all pigs showed typical symptoms of classical swine fever (CSF), such as leucopenia and high fever. There were few differences in clinical signs and survival times between each group. However, the appearance of some symptoms of CSF had a tendency to be delayed following infection with the WB82 strain, when compared with the WB82/E(+) strain. Virus isolation and detection of subgenomic (sg) and full-length viral (flv) RNA by RT-PCR was carried out using sera, 10% homogenized organs and oral, nasal and rectal swabs. Both noncytopathogenic helper virus and cp DI particles were detected in samples from pigs infected with the WB82 strain, but only noncp phenotype virus was isolated from pigs infected with the WB82/E(+) strain. Interestingly, the cp DI particles appeared six to seven days later than helper virus in sera from pigs infected with the WB82 strain. Although active cp DI particles could not be isolated from swabs, sg RNA as well as flv RNA was detected in swabs from animals infected with the WB82 strain. These results suggest that progeny cp DI particles are replicated from parent DI particles after noncp virus replication, and subsequently discharged from infected animals. Furthermore, propagation of DI particles or replication of sg RNA, following propagation of helper virus, appears to inhibit the appearance of CSF symptoms induced by virulent helper CSFV.

Animals↗
PubMed2002

Bacterial distribution and phylogenetic diversity in the Changjiang estuary before the construction of the Three Gorges Dam.

The bacterial community structure in the Changjiang estuary was studied for comparison with future changes, related to the construction of the Three Gorges Dam. Population densities of bacteria in the surface water at station C1 estimated by CFU on marine agar plates and by DAPI direct count, were 2.8 x 10(4) ml(-1) and 4.2 x 10(5) ml(-1), respectively. Physicochemical properties of water, such as temperature and salinity, suggested that station C1 was affected by freshwater from the Changjiang River. Cluster analysis of the PCR-RFLP patterns obtained from 9 samples showed that the bacterial community structure at station C1 was different from the structure at the other stations. Bacterial diversity in the surface water at station C1 was studied based on the genotypes of the 250 clones of 16S rRNA, and on the phenotypes generated on Biolog GN plates for 70 isolates. Sequences of bacteria from two common marine groups, alpha- and gamma-Proteobacteria, were frequently observed. Some other divisions, including the beta-Proteobacteria, C/F/B group, low G+C gram positive, high G+C gram positive, chloroplasts, and relatives of Verrucomicrobia were also observed. The putative dominant species based on both genotype and phenotype analyses were close relatives of Alteromonas macleodii or Roseobacter spp. These results reflected the nutrient-rich environment at station C1.

Bacteria↗
PubMed2001

Lower excitability of the corticospinal tract to transcranial magnetic stimulation during lengthening contractions in human elbow flexors.

The purpose of this study was to characterize the neuromuscular control during shortening (SHO) and lengthening (LEN) contractions by investigating the input-output (I/O) property in the corticospinal tract. To this end, the relation between various stimulus intensities applied via transcranial magnetic stimulation and the size of motor evoked potentials was investigated in six healthy subjects during elbow flexion and extension. The measured I/O property demonstrates a sigmoidal shape, and is characterized by a plateau value, maximum slope and threshold. The results demonstrated that both the plateau value and maximum slope were significantly lower during LEN contraction than during SHO contraction (P<0.05), whereas the threshold was found not to be significantly different. These results suggest that both the maximum excitation level and the gain of the corticospinal tract are reduced during LEN contractions.

Action Potentials↗
PubMed2001

Effects of posture on cardiac autonomic nervous activity in patients with congestive heart failure.

OBJECTIVES: We aimed to clarify which recumbent position is preferred by patients with congestive heart failure (CHF) and to evaluate whether cardiac autonomic nervous activity is different among three recumbent positions (supine, left lateral decubitus, right lateral decubitus) in patients with CHF. BACKGROUND: It remains unclear whether cardiac autonomic nervous activity is different among three recumbent positions in patients with CHF. METHODS: We studied 17 male CHF patients (66+/-7 years) and 17 age- and gender-matched healthy subjects (66+/-7 years). Each subject underwent 24-h ambulatory electrocardiographic monitoring. A channel was used to record the CM5 lead, and another to record the signal of the patient's posture with use of a newly developed small-sized detector (3.2 cm x 3.2 cm). By using spectral analysis of heart rate variability, frequency-domain measures were calculated and compared among the three recumbent positions. Normalized high-frequency (HF: 0.15 to 0.40 Hz) power was used as an index of vagal activity and the low frequency (0.04 to 0.15 Hz)/HF power ratio was used as an index of sympathovagal balance. RESULTS: In patients with CHF, the time for the right lateral decubitus position was two-fold longer than that for the supine and left lateral decubitus positions. The increased cardiac sympathetic activity and decreased vagal tone in CHF patients were normalized in the right lateral decubitus position. CONCLUSIONS: The right lateral decubitus position in patients with CHF may be a self-protecting mechanism of attenuating the imbalance of cardiac autonomic nervous activity.

Aged↗
PubMed2001

Adenovirus-mediated transduction of Escherichia coli uracil phosphoribosyltransferase gene increases the sensitivity of esophageal cancer cells to 5-fluorouracil.

Esophageal cancer is associated with the poorest prognosis among the digestive tract cancers, and chemotherapy is the treatment of choice for many patients. In this study, we experimentally introduced an Escherichia coli-derived uracil phosphoribosyltransferase (UPRT) gene to cultured esophageal cancer cell lines to potentiate the antitumor effects of a representative anticancer drug, 5-fluorouacil (5-FU). UPRT is a pyrimidine salvage enzyme that catalyzes the synthesis of uridine monophosphate from uracil and PRPP. The UPRT gene was transduced into five cultured esophageal cancer cell lines, TE1, TE2, TE3, NUEC1, and T.T, using an adenovirus vector. It was confirmed that the sensitivities of all cultured cell lines to 5-FU were increased in vitro. Subsequently, the T.T line was subcutaneously inoculated into nude mice to induce tumors, after which 5-FU was administered intraperitoneally. When a UPRT gene-recombinant adenovirus vector was directly injected into the tumors, tumor proliferation was markedly inhibited compared with that in the group treated with 5-FU alone, suggesting potentiation of 5-FU sensitivity by UPRT gene transduction in vivo. Therefore, we potentiated the effects of commercially available anticancer drugs by gene transduction. Our method may prove useful as a new form of cancer gene therapy in the future.

Adenoviridae↗
PubMed2001

Genetic characterization and evolutionary implications of a car gene cluster in the carbazole degrader Pseudomonas sp. strain CA10.

The nucleotide sequences of the 27,939-bp-long upstream and 9,448-bp-long downstream regions of the carAaAaBaBbCAc(ORF7)Ad genes of carbazole-degrading Pseudomonas sp. strain CA10 were determined. Thirty-two open reading frames (ORFs) were identified, and the car gene cluster was consequently revealed to consist of 10 genes (carAaAaBaBbCAcAdDFE) encoding the enzymes for the three-step conversion of carbazole to anthranilate and the degradation of 2-hydroxypenta-2,4-dienoate. The high identities (68 to 83%) with the enzymes involved in 3-(3-hydroxyphenyl)propionic acid degradation were observed only for CarFE. This observation, together with the fact that two ORFs are inserted between carD and carFE, makes it quite likely that the carFE genes were recruited from another locus. In the 21-kb region upstream from carAa, aromatic-ring-hydroxylating dioxygenase genes (ORF26, ORF27, and ORF28) were found. Inductive expression in carbazole-grown cells and the results of homology searching indicate that these genes encode the anthranilate 1,2-dioxygenase involved in carbazole degradation. Therefore, these ORFs were designated antABC. Four homologous insertion sequences, IS5car1 to IS5car4, were identified in the neighboring regions of car and ant genes. IS5car2 and IS5car3 constituted the putative composite transposon containing antABC. One-ended transposition of IS5car2 together with the 5' portion of antA into the region immediately upstream of carAa had resulted in the formation of IS5car1 and ORF9. In addition to the insertion sequence-dependent recombination, gene duplications and presumed gene fusion were observed. In conclusion, through the above gene rearrangement, the novel genetic structure of the car gene cluster has been constructed. In addition, it was also revealed that the car and ant gene clusters are located on the megaplasmid pCAR1.

Amino Acid Sequence↗
PubMed2001

Functional organisation of anterior thoracic stretch receptors in the deep-sea isopod Bathynomus doederleini: behavioural, morphological and physiological studies.

The relationship between segmental mobility and the organisation of thoracic stretch receptors was examined in the deep-sea isopod Bathynomus doederleini, which shows a developed adaptive behaviour during digging. The movements of segments during digging were analysed from video recordings, which showed that a large excursion occurred in the anterior thoracic segments. Dye-fills of axons revealed four types of thoracic stretch receptor (TSR): an N-cell type (TSR-1), a differentiated N-cell type (TSR-2), a muscle receptor organ (MRO)-type with a long, single receptor muscle (TSR-3) and an MRO-type with a short, single receptor muscle (TSR-4 to TSR-7). Physiologically, TSR-1 and TSR-2 are tonic-type stretch receptors. TSR-3 to TSR-7 show two kinds of stretch-activated responses, a tonic response and a phasico-tonic response in which responses are maintained as long as the stretch stimulus is delivered. Both TSR-2, with a long muscle strand, and TSR-3, with a single, long receptor muscle, have a wide dynamic range in their stretch-activated response. In addition, TSR-2 is controlled by an intersegmental inhibitory reflex from TSR-3. These results suggest that, although TSR-1 has no receptor muscle and TSR-2 has a less-differentiated receptor-like muscle, they are fully functional position detectors of segmental movements, as are the MRO-type receptors TSR-3 to TSR-7.

Animals↗
PubMed2001

Circadian variation of autonomic nervous activity in patients with multivessel coronary spasm.

The present study investigated whether the circadian rhythm of sympathovagal activity is related to the severity of coronary spasm or multivessel coronary spasm. Heart rate variability was examined in 22 consecutive patients with vasospastic angina provoked by intracoronary injection of acetylcholine, who had either multivessel spasm (Group M, n=11 ) or single vessel spasm (Group S, n= 11), in 20 subjects without coronary artery disease (Group C) and 20 patients with effort angina who had organic coronary artery stenosis (Group E). The frequency domain indices were analyzed, including low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.4Hz), the latter being an index of efferent parasympathetic activity, and the ratio (L/H) as an index of sympathovagal balance. The circadian variation of the parameters was analyzed by its pattern and was quantified by the difference of the mean values between daytime and nighttime. Although the HF power increased during nighttime in Groups C and S, this increase was attenuated in Groups E and M. The circadian variation of the L/H ratio (ie, a drop during nighttime) was smaller in the S and M groups than in Groups C and E. Accordingly, in Group M, the circadian variation of both sympathetic and parasympathetic nervous activity was attenuated, but in Group S, the variation of sympathetic nervous activity, but not parasympathetic nervous activity, was decreased. These data suggest that relatively enhanced sympathetic nervous activity at night may be involved in the mechanism underlying multivessel coronary spasm.

Acetylcholine↗
PubMed2001

Characterization of classical swine fever virus associated with defective interfering particles containing a cytopathogenic subgenomic RNA isolated from wild boar.

Classical swine fever virus (CSFV) strain WB82, isolated from a wild boar in 1982, induced a distinct cytopathic effect (CPE) in primary swine testicle cell culture and in most of the porcine cell lines. This strain of CSFV was found to be composed of two biotypes. cytopathogenic (cp) CSFV, as a minor population, and noncytopathogenic (noncp) CSFV, as a major population. The noncp CSFV (designated strain WB82/E+) was obtained by biological cloning, and it showed the exaltation of Newcastle disease virus phenomenon. In Northern blot analysis and RT-PCR assay, CSFV RNA with a subgenomic (sg) length was detected in addition to full-length viral RNA only in the cells in which a CPE had been revealed. These RNAs represent the genomes of typical defective interfering (DI) particles because of the strict dependence on a complementing helper virus and interference with replication of the helper virus. The sg RNA, which exhibits the genomes of the DI particles, lacked the nucleotides of the viral genomic region from Npro to NS2 (4764 bases). When extracted sg RNA was transfected to the cells infected with the WB82/E+ strain, a distinct CPE was observed. Interestingly, the CPE was observed in cells infected with other heterologous noncp CSFV ALD and GPE- strains by sg RNA transfection. The results suggested that these noncp CSFVs act as helper viruses for the replication of sg RNA (DI particles). It was also shown that the cytopathogenicity of strain WB82 is caused by apoptosis.

Animals↗
PubMed2001

A case of amelogenesis imperfecta of deciduous and all permanent teeth.

We experienced a case with severe enamel defects of both the deciduous teeth and all the permanent teeth. In order to clarify the etiology of enamel defects in this patient, we performed a DNA analysis in addition to conventional examinations. Although we suspected a variety of systemic factors causing enamel defects, there was no evidence suggesting disturbances of amelogenesis. In the present case, we suspected a mutation in the amelogenin gene and performed nucleotide sequencing of the exons of the amelogenin gene, but we could not find any evidence of mutation. We suggest that a mutation of some other gene related to enamel formation or the adventitious factors contributed to the amelogenesis imperfecta in this case.

Adolescent↗
PubMed2000

Effects of posture on sympathetic nervous modulation in patients with chronic heart failure.

We investigated which recumbent position is preferred by patients with chronic heart failure (CHF) and whether sympathetic nervous modulation differs in three recumbent positions. We assessed 12 patients with CHF by spectral analysis of heart-rate variability and measurement of plasma norepinephrine concentrations. The right lateral decubitus position was preferred for significantly longer periods than the left lateral decubitus and supine positions. Sympathetic nervous modulation was most attenuated in the right lateral decubitus position. The right lateral decubitus position preferred by patients with CHF may be a self-protective mechanism to control increased sympathetic nervous modulation.

Heart Failure↗
PubMed2000

Structure of insect chitin isolated from beetle larva cuticle and silkworm (Bombyx mori) pupa exuvia.

Chitin samples in a alpha-form structure were isolated from beetle larva cuticle and silkworm (Bombyx mori) pupa exuvia by treatment with 1 N HCl and 1 N NaOH. Chitosan was prepared by treating them in 40% NaOH containing NaBH(4). Chitin and chitosan were analyzed by X-ray, [13C]CP/MAS NMR, [13C]FT-NMR, and scanning electron microscopy (SEM) methods. Insect chitin degraded more readily than shrimp chitin when treated with 6 N HCl and the enzyme-chitinase. After treatment with 2 N HCl at 100 degrees C, the insect chitin crystallinity increased. N-deacetylation of insect chitin was easier than that of crustaceous chitin, and about 94% of the N-acetyl groups were removed in one treatment with 40% NaOH for 4 h at 110 degrees C. After treatment with 2 N HCl, 55% of the N-acetyl groups of silkworm chitin were removed under the same conditions. Beetle chitin showed a higher affinity for chitinase than shrimp chitin.

Animals↗
PubMed2000

Survey of dental treatments for pediatric patients referred to the pediatric dental clinic of a dental school hospital.

This survey was conducted to clarify which dental treatments in children are regarded as difficult by general dentistry practitioners. The subjects were 615 children who first visited Tokyo Dental College Chiba Hospital from January 1995 to August 1999 with reference letters. There were 615 children in the study; 571 (92.8%) came from Chiba City where our hospital is located and the 11 regions surrounding Chiba City. The prime reasons for referral in the order of frequency were treatments of dental caries, malalignment/malocclusion, traumatized teeth, supernumerary teeth, retarded eruption/impacted teeth, abnormal direction of erupted teeth, congenitally missing teeth, prolonged retention of deciduous teeth, and abnormal frenulum. Patients with dental caries or traumatized teeth in the deciduous dentition period and those with malalignment/malocclusion, supernumerary teeth, or retarded eruption/impacted teeth in the mixed dentition period were often referred to medical organizations specializing in pediatric dentistry because of the difficulties in controlling the patients' behavior and in providing adequate treatment. The information about pediatric dental treatments considered difficult by general dentists revealed by this survey appears to be useful and needs to be incorporated in the programs for clinical training of undergraduate students and education of postgraduate students.

Adolescent↗
PubMed1999

Phase II trial of 5-fluorouracil and low-dose cisplatin in patients with squamous cell carcinoma of the esophagus.

A phase II study was conducted to determine the clinical efficacy and toxicity of 5-fluorouracil (5-FU) and low-dose cisplatin (CDDP) in patients with squamous cell carcinoma of the esophagus. Chemotherapy consisted of 5-FU at a dose of 330 mg/m2 per day, given as a 24-h infusion on days 1-7, and CDDP at a dose of 6 mg/m2 per day, given as a 2-h infusion on days 1-5. Either two or four cycles of chemotherapy were administered to 20 patients with stage III advanced esophageal carcinoma. All 20 patients were then assessed for response and toxicity. An objective response was demonstrated by 11 of the 20 patients, with one complete response (CR) and ten partial responses (PR), bringing the response rate to 55%, with a 95% confidence interval of 27% to 83%. Surgical resection of the tumor was performed in all 20 patients. One patient was found to have a grade 3 histological CR. The median survival of all the patients was 20.5 months, with a range of 4.5 to 48.0 months. Neutropenia and thrombocytopenia developed in five (25%) and two (10%) patients, respectively, and the nonhematologic toxicities were insignificant. The findings of this phase II study indicate that preoperative treatment using 5-FU and low-dose CDDP chemotherapy for patients with advanced esophageal carcinoma appears to achieve a high response rate after short-term administration without affecting the quality of sophisticated lymph node dissection.

Aged↗
PubMed1999

The current status of dentistry, particularly pediatric dentistry, among the countries and territories of Asia.

The number of dentists in Japan may be too high. The ratio of dentists/population, in China, Indonesia, Thailand, and Malaysia, is less than 1 dentist for every 10,000 people. From this data, it can be seen that there is a shortage of dentists in China, Indonesia, Thailand, and Malaysia. The shortage of pediatric dentists in these Asian countries is serious, particularly in the Philippines where the number of children with dental caries is increasing. There is an urgent need to increase the number of pediatric dentists in these countries. However, one problem is that dental schools in the Philippines and Singapore, do not have a department of pediatric dentistry.

Asia↗
PubMed1999

Inhibitory effects of ursodeoxycholic acid on N-methylnitrosourea-induced colon carcinogenesis and colonic mucosal telomerase activity in F344 rats.

Bile acids are known to promote colon carcinogenesis. However, one study showed that ursodeoxychlic acid (UDCA) prevented azoxymethane-induced rat colon tumorigenesis. The aim of the present study with 3 sets of experiments was to explore the inhibitory effect of UDCA supplemented in the diet on colon carcinogenesis induced by the intrarectal administration of N-methylnitrosourea (MNU) in F344 rats. In experiment I, 5 rats per group were fed a diet supplemented with 0% (control), 0.4%, 0.08% or 0.016% UDCA or chenodeoxycholic acid (CDCA) for 5 weeks after receiving 3 intrarectal doses of 4 mg MNU in week 1. The formation of colonic aberrant crypt foci (ACFs, preneoplastic lesions) at week 6 showed a 24% and 23% reduction in the 0.4% and 0.08% UDCA groups, respectively, as compared to the control group, while it increased for the 0.4% and 0.08% CDCA groups, and was unaffected in the 0.016% UDCA and CDCA groups. In experiment II based on the results of experiment I, all rats received an intrarectal dose of 2 mg MNU 3 times a week for 3 weeks, and then were administered with 0%, 0.4% or 0.08% UDCA for 27 weeks. At week 30, the incidence of colon tumors in the UDCA groups was significantly lower than that in the control group: 20/50 (40%) and 9/25 (36%) vs. 17/25 (68%). The number of large-sized ACFs with 4 or more ACs showed a 47% and 59% reduction in the normal-appearing mucosa in the UDCA groups as compared to the control group, while the number of small-sized ACFs with 1-3 ACs was similar in all groups. The normal-appearing mucosa showed a noticeable level of telomerase activity (semiquantitative PCR-based TRAP assay) in the control group, and significantly reduced levels in the UDCA groups compared to the control group: 19.8 and 32.7 vs. 71.0 TPG unit in mean value. The colon tumors showed a high level of enzyme activity in both the control and UDCA groups. In experiment III, 6 rats per group were fed a diet supplemented with 0%, or 0.4% UDCA or CDCA for 5 weeks after receiving 3 intrarectal doses of 4 mg MNU in week 1. Two control groups did not receive any treatment with MNU and bile acids. The MNU-treated groups showed significantly elevated levels of colonic mucosal telomerase activity at week 6 as compared to the control group (6.5 TPG unit in mean value). It was noted that both UDCA and CDCA administration reduced the enzyme activity as compared to the group with MNU treatment alone: 24.7 and 25.2 vs. 40.1 TPG unit in mean value. Thus, the present study suggested that orally administered UDCA inhibited the growth of ACFs and the development of carcinomas in the colon of rats treated with MNU. Also, UDCA may suppress MNU-induced telomerase activation in normal-appearing but ACF-containing colon mucosa, and its mechanism appears to be different from that responsible for the anti-tumor promoting action of UDCA.

Animals↗
PubMed1999

[Treatment of solid tumor by a direct electric current].

This is a case report of a 37-year-old Japanese married female with laryngeal sarcoma, treated by direct electric current so as to obtain remission for more than 4 years without signs of recurrence. Due to her hoarseness and laryngeal numb feeling she underwent a laryngeal examination including a biopsy, resulting in a diagnosis of sarcoma. She refused a total laryngectomy and was given Cobalt treatment of 40 Grey. In the following several months, no improvement was observed, objectively or subjectively. In Nagoya University Hospital the patient then received direct electric current therapy of 36 Coulombs through two platinum electrodes inserted into the tumor under a CT guide, pericutaneously. Two months later, as the hoarseness remained in spite of some improvement, she underwent another session of direct electric current therapy of 14.4 Coulombs through the platinum electrodes by bronchoscope-guided direct insertion. Her hoarseness soon disappeared thereafter and there was a regression of the tumor in 6 months. She did well thereafter without any signs of recurrence for 4 years. Clinical treatment of solid tumors with electric treatment with direct electric current has been done in more than 8,000 cases with CR in 25% of all cases and PR in 50%. Its mechanism, however, remains unclear. In our experimental animal studies, apoptosis was observed. It is considered that this electric therapy using direct electric current will be recognized as one method to treat solid tumors.

Adult↗