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Biomedical subjects

T Noda

Publications and source records attributed to T Noda.

At least 235 records · Page 13Linked to original sources
PubMed1995

Identification of mycobacteria by nonradioisotopic single-strand conformation polymorphism analysis.

Clinical isolates of mycobacteria were identified to species levels using nonradioisotopic single-strand conformation polymorphism (non-RI SSCP) analysis of 16S rRNA gene fragments amplified by polymerase chain reaction with primers common to all of mycobacterial species. The method is based on a hypervariable region within the 16S rRNA in mycobacteria, which is characterized by species-specific nucleotide sequences. A total of 92 mycobacterial strains (Mycobacterium tuberculosis, M. avium, M. gordonae, M. intracellulare, M. kansasii, M. chelonae, M. nonchromogenicum, M. xenopi, and unidentified strain) were studied. They were classified into nine types of pattern showing single-strand DNA bands having different mobilities. Each strain was shown in the species-specific mobility by non-RI SSCP analysis. The results of non-RI SSCP analysis were identical to those of standard biochemical methods and 16S rRNA sequencing.

DNA Primers↗
PubMed1995

Assessment of portal vein invasion by bile duct cancer using intraductal ultrasonography.

BACKGROUND AND STUDY AIMS: We recently reported on the contribution of intraductal ultrasonography (IDUS) to the regional staging of bile duct cancer, and we present here the first detailed study of the value of IDUS in assessing the portal vein invasion by bile duct cancer. PATIENTS AND METHODS: Preoperative assessment of portal vein invasion was performed by IDUS via a percutaneous tract or via transpapillary route in 18 patients with extrahepatic bile duct cancer. Various probes, with diameters of 1.4, 2.0, 2.4, 2.6, and 3.2 mm, and frequencies of 7.5, 15, 20, and 30 MHz, were used. All patients additionally underwent endoscopic ultrasonography (EUS) and angiography. In the first six cases, the IDUS and EUS images were analyzed retrospectively without the knowledge of operative results or the other imaging tests. In the remaining 12 cases, IDUS and EUS images were prospectively reviewed prior to surgery, without knowledge of the angiographic findings. The gold standard for the results of IDUS, EUS and angiography was the histopathological findings in 17 resected tumors, and the intraoperative findings in one patient who did not undergo resective surgery. RESULTS: IDUS was able to demonstrate the portal vein in all cases. Its accuracy in diagnosing portal vein invasion was 100% for all locations. EUS was useful in assessing portal vein invasion at the middle and distal bile duct (the accuracy was 91%), but was not useful in assessing invasion at the proximal bile duct (the accuracy was 57%). CONCLUSIONS: IDUS proved useful for assessing the extension of cancer invasion into the portal vein, even in proximal bile duct tumors.

Aged↗
PubMed1995

Assessment of hepatic artery invasion by bile duct cancer using intraductal ultrasonography.

BACKGROUND AND STUDY AIMS: This study was performed to clarify the diagnostic accuracy of intraductal ultrasonography (IDUS) in assessing hepatic artery invasion by bile duct cancer. PATIENTS AND METHODS: Preoperative assessment of hepatic artery invasion was performed by IDUS via a percutaneous tract or the transpapillary route in a total of 22 patients with extrahepatic bile duct cancer. The probes used had a diameter of 1.4, 2.0, 2.4, 2.6, and 3.2 mm, and frequencies of 7.5, 15, 20, and 30 MHz. In the first six cases, IDUS images were analyzed retrospectively with no knowledge of the operative results or of the other imaging tests. In the following 16 cases, the IDUS images were prospectively reviewed prior to surgery without knowledge of the angiographic findings. The diagnostic accuracy of IDUS was compared with angiography in all cases, with the histopathological results in 20 resected cases, and with the intraoperative findings in two cases with only surgical exploration. RESULTS: IDUS was able to demonstrate the right hepatic artery in all cases, and its accuracy in diagnosing right hepatic invasion was 100%. However, IDUS was able to visualize the proper hepatic artery in only four cases (18%), and the left hepatic artery in only three cases (14%), respectively. IDUS could not visualize the area outside of the hepatoduodenal ligament, because of its low penetration depth. CONCLUSIONS: IDUS proved useful for assessing the extension of bile duct cancer invasion into the right hepatic artery. However, IDUS did not sufficiently demonstrate the proper hepatic artery and the left hepatic artery for diagnosing vascular involvement.

Aged↗
PubMed1995

Characteristics of choledochal cysts in neonates and early infants.

Thirty-six infants with choledochal cyst consisting of 28 babies less than 12 months of age and 8 between 13 and 24 months of age, were analyzed. Characteristics of cases were as follows: (1) they were usually of the cystic type, (2) a huge abdominal mass and jaundice with alcoholic stool were typically found, (3) no symptom suggesting acute pancreatitis was observed, (4) amylase levels in bile were usually low, despite the presence of pancreatobiliary malunion, while other pancreatic enzymes in bile commonly showed a high concentration, and (5) primary cyst excision and biliary reconstruction was the treatment of choice, and could be safely performed with favorable outcomes even in babies less than 1 year of age.

Amylases↗
PubMed1995

Synapsin I deficiency results in the structural change in the presynaptic terminals in the murine nervous system.

Synapsin I is one of the major synaptic vesicle-associated proteins. Previous experiments implicated its crucial role in synaptogenesis and transmitter release. To better define the role of synapsin I in vivo, we used gene targeting to disrupt the murine synapsin I gene. Mutant mice lacking synapsin I appeared to develop normally and did not have gross anatomical abnormalities. However, when we examined the presynaptic structure of the hippocampal CA3 field in detail, we found that the sizes of mossy fiber giant terminals were significantly smaller, the number of synaptic vesicles became reduced, and the presynaptic structures altered, although the mossy fiber long-term potentiation remained intact. These results suggest significant contribution of synapsin I to the formation and maintenance of the presynaptic structure.

Animals↗
PubMed1995

Growth retardation in human cervical dysplasia-derived cell lines by beta-carotene through down-regulation of epidermal growth factor receptor.

We used newly established cervical dysplasia-derived cell lines to elucidate a molecular mechanism of the preventive action of beta-carotene in cervical multi-step carcinogenesis. Liposomal beta-carotene was added to the culture medium for human cervical dysplasia cell lines, CICCN-2 from cervical intraepithelial neoplasia grade I (CIN I), CICCN-3 from CIN II, and CICCN-4 from CIN III, and human cervical carcinoma-derived cell lines such as CICCN-6, CICCN-18, and HeLa cells. beta-Carotene (10 mumol/L) induced significant growth retardation in three cervical dysplasia cell lines but not in three cervical carcinoma-derived cell lines. Binding activities of epidermal growth factor (EGF) and cellular amounts of either messenger RNA for EGF receptor gene or EGF receptor protein were all highest in CICCN-4 cells. Cell surface binding, as well as internalization, of 125I-labeled EGF was rapidly reduced after beta-carotene treatment in dysplasia cell lines and 170-kD protein bands of EGF receptor disappeared from protein immunoblots at day 3 of the treatment. Cellular amounts of EGF receptor messenger RNA remained constant until day 3 of the treatment and were substantially reduced after day 7. Chromatin condensations, morphologic evidence for apoptotic cell death, were observed at day 1 by staining. From these results, we contend that prevention of cervical carcinogenesis by beta-carotene is due to induction of apoptosis in cervical dysplastic cells, which are premalignant cells in cervical multi-step carcinogenesis, via down-regulation of EGF receptor protein.

Anticarcinogenic Agents↗
PubMed1995

Alternations in atrial natriuretic peptide release after DC cardioversion of non-valvular chronic atrial fibrillation.

The response of atrial natriuretic peptide (ANP) release to haemodynamic influences after cardioversion of atrial fibrillation has not been fully examined. We measured plasma concentrations of ANP and assessed haemodynamic changes 60-120 min after DC cardioversion in 22 patients with non-valvular chronic atrial fibrillation. Passive leg elevation to enhance volume expansion was performed 60 min after DC cardioversion. Sinus rhythm was restored in 18 of the 22 patients (successful DC cardioversion group). The control group consisted of seven patients with non-valvular chronic atrial fibrillation who did not undergo DC cardioversion (atrial fibrillation control group). In the successful DC cardioversion group, the mean pulmonary artery wedge pressure decreased significantly 15 min after cardioversion (P < 0.05) and then remained unchanged. Plasma concentrations of ANP also decreased significantly 15 min after cardioversion (P < 0.05). Furthermore, there was an additional significant decrease in ANP levels for up to 60 min after cardioversion (P < 0.05 from 15 min). Passive leg elevation for 15 min led to an increase in the mean pulmonary artery wedge pressure (P < 0.01) and right atrial pressure (P < 0.05), but did not result in increased plasma concentrations of ANP (47.1 +/- 27.6 vs 43.9 +/- 34.4 pg.ml-1, mean +/- SD, P = ns). In the atrial fibrillation control group, passive leg elevation increased the mean pulmonary artery wedge pressure (P < 0.01), the mean right atrial pressure (P < 0.05) and plasma concentrations of ANP (139.9 +/- 85.8 vs 168.1 +/- 108.2, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Helicobacter pylori infection, serum pepsinogen level and gastric cancer: a case-control study in Japan.

We conducted a case-control study to evaluate the effect of Helicobacter pylori (HP) infection on the risk of gastric cancer in Tokyo, Japan. The sera at the time of diagnosis from 282 gastric cancer cases and 767 sex- and age-matched cancer-free controls were tested for the presence of anti-HP IgG antibody (HM-CAP ELISA kit) and serum pepsinogen (PG) level (PG I and PG II Riabead). No significant association was observed in all sets [matched odds ratio (OR) = 1.04, 95% confidence interval: 0.73-1.49]. In subgroup analyses, however, an association was suggested in females [OR = 1.57], a younger population (< 50 years) [OR = 1.86], early cancer [OR = 1.53] and small cancer (< 40 mm) [OR = 1.55]. Furthermore, we observed a tendency for odds ratios to decrease with an increase in age or cancer growth (depth of tumor invasion and tumor size). Considering that the spontaneous disappearance of HP due to extended mucosal atrophy may lead to these decreasing odds ratios, we applied the conditional logistic model adjusted for the PG I/II ratio as a measure of atrophic gastritis. This analysis showed a positive association with HP infection in all sets [OR = 1.69; 1.01-2.81], distal cancer [OR = 1.88; 1.07-3.31] and intestinal-type cancer [OR = 3.76; 1.39-10.18]. We concluded that the risk of cancer associated with HP infection may be underestimated in studies with cross-sectional exposure because of spontaneous disappearance of HP due to extended mucosal atrophy.

Adult↗
PubMed1995

[Basic and clinical evaluation of lysis centrifugation in candidemia].

Basic and clinical evaluation of lysis centrifugation using Isolator 10 was performed and compared with culture bottle methods. Blood, which was inoculated with C. albicans, C. tropicalis or C. parapsilosis, was cultured using lysis centrifugation or culture bottle method. The culture duration of C. albicans and C. parapsilosis by lysis centrifugation was shorter than that by the culture bottle (BHI release). C. albicans, C. parapsilosis and C. tropicalis became culture-positive within 1 or 2 days after culture by lysis centrifugation. C. albicans and C. parapsilosis became positive 4 days and C. tropicalis 6-8 days after culture by the culture bottle (BHI super). Clinical evaluation of both blood culture method as performed from April 1990 to March 1994. Sixty samples (4.4%) were positive out of 1370 samples. Twenty eight samples (7.2%) were positive out of 389 samples, which were examined by both methods. Twenty two samples were positive by both methods and the rest of the 6 samples was positive only by Lysis centrifugation.

Blood↗
PubMed1995

[Isolation of Cryptococcus neoformans from environments (pigeon excreta) in Nagasaki].

Cryptococcosis is one of the serious deep-seated mycoses in immunocompromised patients, especially those with AIDS. Cryptococcus neoformans ordinarily lives in natural environments such as soil and reproduces in pigeon excreta. It spreads in the air and infects human by inhalation. We isolated C. neoformans from pigeon excreta in hospitals, private houses, parks in Nagasaki from October to December in 1994. C. neoformans was isolated from 4 of 8 samples (50%) of pigeon excreta and the isolation rate increased to 80% (4/5) if they were weathered excreta. Two patients with pulmonary cryptococcosis occurred in the last two years in the area where C. neoformans was isolated during that period. Epidemiological studies of clinical isolates and environmental isolates are important to determine its origin of infection and the route of transmission.

Animals↗
PubMed1995

Inositol monophosphatase activity from the Escherichia coli suhB gene product.

The suhB gene is located at 55 min on the Escherichia coli chromosome and encodes a protein of 268 amino acids. Mutant alleles of suhB have been isolated as extragenic suppressors for the protein secretion mutation (secY24), the heat shock response mutation (rpoH15), and the DNA synthesis mutation (dnaB121) (K. Shiba, K. Ito, and T. Yura, J. Bacteriol. 160:696-701, 1984; R. Yano, H. Nagai, K. Shiba, and T. Yura, J. Bacteriol. 172:2124-2130, 1990; S. Chang, D. Ng, L. Baird, and C. Georgopoulos, J. Biol. Chem. 266:3654-3660, 1991). These mutant alleles of suhB cause cold-sensitive cell growth, indicating that the suhB gene is essential at low temperatures. Little work has been done, however, to elucidate the role of the product of suhB in a normal cell and the suppression mechanisms of the suhB mutations in the aforementioned mutants. The sequence similarity shared between the suhB gene product and mammalian inositol monophosphatase has prompted us to test the inositol monophosphatase activity of the suhB gene product. We report here that the purified SuhB protein showed inositol monophosphatase activity. The kinetic parameters of SuhB inositol monophosphatase (Km = 0.071 mM; Vmax = 12.3 mumol/min per mg) are similar to those of mammalian inositol monophosphatase. The ssyA3 and suhB2 mutations, which were isolated as extragenic suppressors for secY24 and rpoH15, respectively, had a DNA insertion at the 5' proximal region of the suhB gene, and the amount of SuhB protein within mutant cells decreased. The possible role of suhB in E. coli is discussed.

Base Sequence↗
PubMed1994

Human glycyl-tRNA synthetase. Wide divergence of primary structure from bacterial counterpart and species-specific aminoacylation.

Several class I and class II human tRNA synthetases are clearly related to their bacterial counterparts. We report here the cloning, cDNA sequence, deduced primary structure, and expression in bacteria of a class II human glycyl-tRNA synthetase. While the human sequence aligns well with a Bombyx mori and a Saccharomyces cerevisiae sequence for glycyl-tRNA synthetase, particularly in the region of the class II-defining sequence motifs, it diverges widely from that of the Escherichia coli enzyme. The divergence is so great that from the sequences alone we cannot conclude that the human and E. coli proteins are descended from homologous genes. Moreover, even though the human and E. coli class II alanyl-tRNA synthetases cross-acylate their respective tRNAs, aminoacylations by the recombinant human and E. coli glycyl-tRNA synthetases are restricted to their homologous tRNAs. The species-specific aminoacylations correlate with a nucleotide sequence difference at a location in the acceptor stem that is known to be critical for aminoacylations by the E. coli enzyme. Thus, glycyl-tRNA synthetase may have followed a path of historical development different in at least some respects from that of several other tRNA synthetases.

Acylation↗
PubMed1994

Human cytoplasmic isoleucyl-tRNA synthetase: selective divergence of the anticodon-binding domain and acquisition of a new structural unit.

We show here that the class I human cytoplasmic isoleucyl-tRNA synthetase is an exceptionally large polypeptide (1266 aa) which, unlike its homologues in lower eukaryotes and prokaryotes, has a third domain of two repeats of an approximately 90-aa sequence appended to its C-terminal end. While extracts of Escherichia coli do not aminoacrylate mammalian tRNA with isoleucine, expression of the cloned human gene in E. coli results in charging of the mammalian tRNA substrate. The appended third domain is dispensable for detection of this aminoacylation activity and may be needed for assembly of a multisynthetase complex in mammalian cells. Alignment of the sequences of the remaining two domains shared by isoleucyl-tRNA synthetases from E. coli to human reveals a much greater selective pressure on the domain needed for tRNA acceptor helix interactions and catalysis than on the domain needed for interactions with the anticodon. This result may have implications for the historical development of an operational RNA code for amino acids.

Amino Acid Sequence↗
PubMed1994

Excitation-contraction uncoupling and muscular degeneration in mice lacking functional skeletal muscle ryanodine-receptor gene.

Contraction of skeletal muscle is triggered by the release of Ca2+ from the sarcoplasmic reticulum (SR) after depolarization of transverse tubules. The ryanodine receptor exists as a 'foot' protein in the junctional gap between the sarcoplasmic reticulum and the transverse tubule in skeletal muscle, and is proposed to function as a calcium-release channel during excitation-contraction (E-C) coupling. Previous complementary DNA-cloning studies have defined three distinct subtypes of the ryanodine receptor in mammalian tissues, namely skeletal muscle, cardiac and brain types. We report here mice with a targeted mutation in the skeletal muscle ryanodine receptor gene. Mice homozygous for the mutation die perinatally with gross abnormalities of the skeletal muscle. The contractile response to electrical stimulation under physiological conditions is totally abolished in the mutant muscle, although ryanodine receptors other than the skeletal-muscle type seem to exist because the response to caffeine is retained. Our results show that the skeletal muscle ryanodine receptor is essential for both muscular maturation and E-C coupling, and also imply that the function of the skeletal muscle ryanodine receptor during E-C coupling cannot be substituted by other subtypes of the receptor.

Animals↗
PubMed1994

Altered microtubule organization in small-calibre axons of mice lacking tau protein.

The tau gene encodes a protein (Tau) that is a major neuronal microtubule-associated protein localized mostly in axons. It has microtubule-binding and tubulin-polymerizing activity in vitro and is thought to make short crossbridges between axonal microtubules. Further, tau-transfected non-neuronal cells extend long axon-like processes in which microtubule bundles resembling those in axons are formed. In contrast, tau antisense oligonucleotides selectively suppress axonal elongation in cultured neurons. Thus tau is thought to be essential for neuronal cell morphogenesis, especially axonal elongation and maintenance. To test this hypothesis, we used gene targeting to produce mice lacking the tau gene. We show that the nervous system of tau-deficient mice appears to be normal immunohistologically. Furthermore, axonal elongation is not affected in cultured neurons. But in some small-calibre axons, microtubule stability is decreased and microtubule organization is significantly changed. We observed an increase in microtubule-associated protein 1A which may compensate for the functions of tau in large-calibre axons. Our results argue against the suggested role of tau in axonal elongation but confirm that it is crucial in the stabilization and organization of axonal microtubules in a certain type of axon.

Animals↗