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Biomedical subjects

N Satoh

Publications and source records attributed to N Satoh.

At least 145 records · Page 8Linked to original sources
PubMed1997

[Relationship between distortion product otoacoustic emissions and pure tone thresholds in normal and hearing-impaired ears].

To establish clinical criteria for distortion product otoacoustic emissions (DPOAEs) in order to distinguish normal-hearing from hearing-impaired ears, DPOAEs were measured and evaluated in 325 normal and 291 cochlear-impaired human ears using an ILO92 Otoacoustic Emission Analyzer. The background noise level was too variational in each individual ear to ignore in DPOAE measurements. Therefore, the value of the difference between the DPOAE amplitude and the background noise level (DPOAE noise) was calculated and compared with the pure tone threshold at 1 kHz, 2 kHz and 4 kHz. It was difficult, however, to precisely separate normal-hearing and hearing impaired ears with DPOAE noise values because many normal ears presented small amplitudes of DPOAEs and some impaired ears showed high amplitudes. Therefore, cumulative distributions of sensitivity (normal hearing ears identified as normal hearing) and specificity (hearing impaired ears identified as hearing impaired) were constructed and used to calculate a cut off point for DPOAE-noise in order to separate normal hearing from hearing impaired ears. It is considered that the cut-off points (DPOAE noise values of 7.3 dB at 1 kHz, 10.3 dB at 2 kHz and 16.1 dB at 4 kHz) at which the false alarm rates (1 specificity: the rate of hearing impaired ears incorrectly identified as normal hearing) correspond to 5% can be useful for clinical evaluation of DPOAEs.

Adolescent↗
PubMed1997

[Lung volume reduction surgery for pulmonary emphysema--report of two cases].

Lung volume reduction surgery (LVR) was practiced in 2 male patients with pulmonary emphysema to improve pulmonary function. On admission, they complained of exertional dyspnea (Grade III of the Hugh-Jones dyspnea scale). Computed tomographic scan (band display) revealed emphysematous changes throughout both lung fields, especially in bilateral upper lobes. Nuclear lung perfusion scintigraphy showed markedly diminished blood flow in both upper lobes. The bilateral upper lobes of each patient were excised through median sternotomy using the linear stapling device. The staple lines were buttressed with bioabsorbable polyglycolic acid fabric. At 1 month after LVR, the forced expiratory volume in 1 second improved, respectively, from 0.51 L to 1.27 L (Case 1) and from 0.68 L to 0.85 L (case 2). In conclusion, LVR was useful to improve pulmonary function of the patients with pulmonary emphysema.

Aged↗
PubMed1997

[Delayed emergence from propofol, nitrous oxide and oxygen anesthesia--a case report].

We report a case of delayed recovery after the termination of propofol and nitrous oxide anesthesia. On the preoperative examination hepatic dysfunction (Indocyanine green (ICG) plasma retention rate at 15 minutes of 22%) was pointed out. Anesthesia was maintained with epidural block, nitrous oxide, oxygen and propofol. Average infusion rate of propofol was 5-6 mg.kg-1.h-1. Although at the end of the operation, the propofol infusion and nitrous oxide were stopped simultaneously, 59 minutes were necessary before the emergence from anesthesia. We consider that an average infusion rate of propofol should be decelerated in a case of ICG clearance time elongation.

Aged↗
PubMed1997

[Automated anesthesia record keeping system in in the United States].

We have implemented an automated anesthesia record keeping system (AARK) since 1992. The system stands in need of re-designing to function as a perioperative patient's information system. We discussed the issues with anesthesiologists who's institutes are implemented with AARK in the United States. We visited the following three institutes: St. Luke's Hospital (Kansas City, MO), University of Florida (Gainesville, FL), and Burbank Hospital (Fitchburg, MA). All of them are implemented with ARKIVE system. Dr. Edsall in Burbank Hospital stressed quality assurance (QA), and using ARKIVE's database for QA. University of Florida has a big anesthesia and engineering team to develop a new ergonomically sound AARK. Some of the members regarded ARKIVE as an "out of date" system. Dr. Tuohy in St. Luke's Hospital stressed cost/benefit of AARK. Taking their experience into account, we are designing a new perioperative patient's information system including AARK.

Anesthesia↗
PubMed1997

Isolation and characterization of cDNA clones for beta-tubulin genes as a molecular marker for neural cell differentiation in the ascidian embryo.

The central nervous system (CNS) of an ascidian tadpole larva is composed of about 340 cells, the lineages of which are well documented. To elucidate the mechanisms underlying the neural induction of ascidians, appropriate molecular markers are required. In this study, to obtain an early differentiation marker of the neural cells, we isolated and characterized cDNA clones for two beta-tubulin genes (HrTBB1 and HrTBB2) of the ascidian Halocynthia roretzi. We found that the HrTBB1 and HrTBB2 amino acid sequences are highly conserved, with 91-98% identities to other invertebrate and vertebrate beta-tubulins. The expression of HrTBB1 was found to be maternal, while HrTBB2 is expressed both maternally and zygotically. We observed that the zygotic expression of HrTBB2 commences at the neural plate stage and is specific to cells of the differentiating CNS. In the larvae, HrTBB2 expression was restricted to cells of the CNS, some cells of the papilla and cells of the peripheral nervous system. These results indicate that HrTBB2 will be a useful early molecular marker for neural cell differentiation in the ascidian embryo.

Amino Acid Sequence↗
PubMed1997

[Head and neck cancer].

Phase II study of nedaplatin (NDP), a new derivative of cisplatin, was completed in 1990, so this agent is now commercially available. NDP is very effective for head and neck cancer. Out of the 90 evaluable patients, CR was achieved in 11 patients and PR in 27 with a response rate of 42%. A new combination chemotherapy containing NDP, especially NDP + 5-FU, was clinically tried. Furthermore concurrent NDP and radiotherapy will be tried in the near future. Phase II study of S-1 (tegafur + CDHP + Oxo) and taxotere (TXT), however, is ongoing. The results obtained so far are almost satisfactory. The aouthor also adopted several new agents which were presented at the ASCO meeting (1993-1997): taxol (TXL), taxotere (TXT), topotecan, amonafide, vinorelbine and thymitaq. Response rates of these agents were as follows: TXL: 26-37%, TXT: 27-41%, topotecan: 0-27%, vinorelbine: 6.7-12.5%, thymitaq: 18.2% and amonafide: 3.6%. So TXL and TXT are very effective for head and neck cancer. In terms of combination chemotherapy, response rates are 33-71% in TXL + CDDP, 23-62% in TXL + CBDCA, 78% in TXT + CDDP and 75% in TXT + CDDP + 5-FU. Concurrent radiotherapy and chemotherapy including new agents are interesting and important issues. Two kinds of protocol were adopted, 5-FU + HU + TXL + RT and TXL + CBDCA + RT. Both protocols are responsive to squamous cell carcinoma of the head and neck. But severe local toxicity (stomatitis) and bone marrow suppression pose problems.

Antineoplastic Agents, Phytogenic↗
PubMed1997

[Prognosis and preoperative imaging of patients with small hepatocellular carcinoma].

We conducted a retrospective study on the relation of the preoperative imaging patterns to the prognosis of patients with small HCC after hepatectomy. Forty patients with small HCC less than 2 cm in diameter without vascular invasion were enrolled in this study. There were no significant differences in the signal intensity of T1WI on MRI, and angiographic findings such as neo-vascularity or tumor stain. Ultrasonographical images of the internal of tumor were classified into two groups. Six cases with homogeneous pattern were significantly worse in cumulative survival rate than 28 cases with heterogeneous pattern (p = 0.0012). The same results were obtained with respect to limitation of cases treated by relative curative operation (p = 0.0041). It was concluded that histopathological grading and malignant potential of small HCC could be evaluated by classification of the pattern of internal ultrasonographical images, and complete locoregional therapy, and that intense course observation for cases with ultrasonographical homogeneous pattern would be important.

Carcinoma, Hepatocellular↗
PubMed1997

Isolation of cDNA clones for genes that are expressed in the tail region of the ascidian tailbud embryo.

An ascidian tailbud embryo is comprised of the anterior trunk and posterior tail. We constructed cDNA libraries of the tail region and trunk region of the ascidian Halocynthia roretzi. The screening of the tail library by tail single-stranded cDNA minus the trunk library RNA as a probe, yielded cDNA clones for genes that are expressed in the tail epidermis, visceral ganglion, trunk lateral cells, muscle cells, and certain regions of the tail. Among them, a cDNA clone for a gene designated HrPost-1 is described in detail. HrPost-1 encodes a novel, possible secreted protein of 238 amino acids. The expression of the gene is zygotic. HrPost-1 transcript was first evident in the posterior B-line blastomeres including muscle cells and endodermal strand cells of the gastrula-stage embryo, and the expression in these regions disappeared by the early tailbud stage. Around neurulation, the HrPost-1 transcript appeared in epidermal cells of the posterior-most region of the embryo. As development proceeded, the gene expression spread anteriorly in the epidermal cells of the neurula and tailbud embryo, and thus at the early-to-mid tailbud stage, HrPost-1 expression appeared to define the boundary between the trunk and tail epidermis. These results suggest that, in addition to tissue-specific genes, the activities of a set of region-specific genes are associated with tail formation in the ascidian embryo.

Amino Acid Sequence↗
PubMed1996

The ascidian genome contains another T-domain gene that is expressed in differentiating muscle and the tip of the tail of the embryo.

The vertebrate Brachyury (T) gene is transiently expressed in nascent and migrating mesoderm, in the differentiating notochord, and in the tail bud, reflecting its independent functions. In contrast, the expression of an ascidian Brachyury gene (As-T) is restricted to differentiating notochord. The present study revealed that the genome of Halocynthia roretzi contains another T-domain gene (As-T2) which encodes a divergent T-domain protein. The transient expression of As-T2 was detected in the endoderm- and muscle-lineage blastomeres of the early embryo and the transcript was retained by involuting and differentiating muscle cells until it became undetectable by the mid-tailbud stage. In addition, As-T2 was expressed transiently in cells that form the tip of the newly forming tail. Interestingly, the combined pattern of spatial expression of As-T and As-T2 appears to correspond to that of a single vertebrate Brachyury gene.

Amino Acid Sequence↗
PubMed1996

An intrinsic genetic program for autonomous differentiation of muscle cells in the ascidian embryo.

The B-line presumptive muscle cells of ascidian embryos have extensive potential for self-differentiation dependent on determinants prelocalized in the myoplasm of fertilized eggs. Ascidian larval muscle cells therefore provide an experimental system with which to explore an intrinsic genetic program for autonomous specification of embryonic cells. Experiments with egg fragments suggested that maternal mRNAs are one of the components of muscle determinants. Expression of larval muscle actin genes begins as early as the 32-cell stage, prior to the developmental fate restriction of the cells. The timing of initiation of the actin gene expression proceeds the expression of an ascidian homologue of vertebrate MyoD by a few hours. Mutations in the proximal E-box of the 5' flanking region of the actin genes did not alter the promoter activity for muscle-specific expression of reporter gene. These results, together with results of deletion constructs of fusion genes, suggest that muscle determinants regulate directly, or indirectly via regulatory factors other than MyoD, the transcription of muscle-specific structural genes leading to the terminal differentiation.

Actins↗
PubMed1996

Molecular cloning of rat leptin receptor isoform complementary DNAs--identification of a missense mutation in Zucker fatty (fa/fa) rats.

We cloned the full-length rat leptin receptor (Ob-R) isoform complementary DNAs (cDNAs) and examined the gene expression in rats. We also identified a mutation in Ob-R in Zucker fatty (fa/fa) rats. Three alternatively spliced isoforms (Ob-Ra, Ob-Rb, and Ob-Re) have been identified, which are closely related to the gp130 signal-transduction component of class I cytokine receptors. Rat Ob-Ra and Ob-Rb were single transmembrane proteins, which differ in the C-terminal amino acid sequences. On the other hand, Ob-Re had no transmembrane domain and was a soluble form of the receptor. Reverse transcription-polymerase chain reaction analysis revealed that Ob-R isoform messenger RNAs (mRNAs) are expressed in a wide variety of rat tissues in tissue-specific manners. A missense mutation (an A to C conversion at nucleotide position 806) was found in the extracellular domain of all the isoforms in Zucker fatty (fa/fa) rats, which resulted in an amino acid change from Gln to Pro at + 269 (the Gln269Pro mutation). These Ob-R isoform mRNAs were present in the brain from Zucker fatty (fa/fa) rats at comparable amounts to those in their lean littermates. The present study provides new insight into the molecular mechanisms for Ob-R.

Alternative Splicing↗
PubMed1996

Duplication of an amphioxus myogenic bHLH gene is independent of vertebrate myogenic bHLH gene duplication.

Gene duplication is thought to be a major genetic change that may have permitted the evolution of vertebrates from invertebrates. The myogenic genes encode basic helix-loop-helix (bHLH) transcriptional factors essential for the formation of skeletal muscle. The invertebrate genome contains only a single myogenic bHLH gene, whereas the vertebrate genome contains four (MyoD, Myf-5, myogenin and MRF4). Since the tunicate genome contains a single myogenic bHLH gene, its duplication might have occurred some time during chordate evolution. To determine whether the duplication of the myogenic bHLH gene occurred prior to, or after the divergence of vertebrates from the cephalochordate lineage, we amplified target fragments from the amphioxus, Branchiostoma floridae, by means of PCR. Sequence analysis and genomic Southern analysis revealed that the amphioxus genome contains two myogenic bHLH genes (BMD1 and BMD2). A comparison of the amino acid sequences in the bHLH domain between BMD1, BMD2 and four vertebrate myogenic bHLH gene products, however, showed that neither BMD1 nor BMD2 resembled any of the four genes. These results suggested that the duplication of amphioxus myogenic bHLH gene occurred independently of that leading to the four myogenic bHLH genes in vertebrates.

Amino Acid Sequence↗
PubMed1996

Mechanism of an evolutionary change in muscle cell differentiation in ascidians with different modes of development.

We have investigated the mechanism of an evolutionary change in ascidian muscle cell differentiation. The ascidians Molgula oculata and Molgula occulta are closely related species with different modes of development. M. oculata embryos develop into conventional tadpole larvae with a tail containing striated muscle cells, whereas M. occulta embryos develop into tailless larvae with undifferentiated vestigial muscle cells. The muscle actin gene MocuMA1 was isolated from an M. oculata genomic library. MocuMA1 is a single-copy, larval-type muscle actin gene which appears to lack introns. However, the 5' upstream region of MocuMA1 is sufficient to drive expression of a lacZ fusion construct in the larval muscle cells, implying that it is a functional gene. MocuMA1 mRNA first appears in the prospective muscle cells of M. oculata embryos during gastrulation, and transcripts continue to be present throughout embryogenesis. Muscle actin mRNA was not detected during M. occulta embryogenesis, although the same probe was capable of detecting muscle actin mRNA in more distantly related ascidian species with tail muscle cells. Interspecific hybrids produced by fertilizing M. occulta eggs with M. oculata sperm recover the ability to express muscle actin mRNA in the vestigial muscle cells, suggesting that trans-acting factors responsible for muscle actin gene expression are conserved in M. occulta. The presence of these trans-acting factors was confirmed by showing that the MocuMA1/lacZ fusion construct is expressed in the vestigial muscle cells of M. occulta larvae. The orthologous larval muscle actin genes MoccMA1a and MoccMA1b were isolated from a M. occulta genomic library. The coding regions of these genes contain deletions, insertions, and codon substitutions that would make their products nonfunctional. Although the 5' upstream regions of the M. occulta muscle actin genes also contain numerous changes, expression of MoccMA1a/lacZ and MoccMA1b/lacZ fusion constructs showed that they both retain specific promoter activity, although it is reduced in MoccMAlb. The results suggest that the regression of muscle cell differentiation is mediated by changes in the structure of muscle actin genes rather than in the trans-acting regulatory factors required for their expression.

Actins↗
PubMed1996

[Analysis of the recent use of an anonymous FTP server in the University of Occupational and Environmental Health, Japan].

An analysis of the recent use of an Anonymous FTP Server in the University of Occupational and Environmental Health, Japan for the distribution of software and documents through Internet was examined. The following points were confirmed. The use of the Anonymous FTP server for receiving files from outside the university rapidly increased after making the Anonymous FTP server public. The average file transfer rate in use from outside the university was less than ten percentage points from that of local use. The time for local use was stabilized, but the time for use outside the university was variable.

Computer Communication Networks↗
PubMed1996

Augmented expression of obese (ob) gene during the process of obesity in genetically obese-hyperglycemic Wistar fatty (fa/fa) rats.

Expression of the obese (ob) gene is up-regulated in the adipose tissue in several obese rodent models. To study the regulation of the ob gene expression during the development of obesity, we examined the ob gene expression in genetically obese-hyperglycemic Wistar fatty (fa/fa) rats at several stages of obesity. The ob mRNA levels in the adipose tissue from Wistar fatty rats was unequivocally augmented and continued to rise in the process of obesity. Furthermore, the ob gene expression in this obese model was much more rapidly enhanced in the mesenteric fat than in the subcutaneous fat. Moreover, the ob gene expression was more greatly augmented in the mesenteric fat than the lipoprotein lipase gene expression. These results suggest the presence of obesity-linked and region-specific regulation of the ob gene expression.

Adipose Tissue↗