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T Nagai

Publications and source records attributed to T Nagai.

At least 19 recordsLinked to original sources
PubMed1992

A carboxyl-terminal truncated version of the activin receptor mediates activin signals in early Xenopus embryos.

The function of a carboxyl-terminal truncated version of the Xenopus activin receptor, encoded by a previously isolated gene XSTK2, was investigated in early embryos. The transcript corresponding to the truncated receptor gene was detected throughout embryonic development although the temporal expression pattern was different from that of an intact receptor. Injection of XSTK2 mRNA into early embryos resulted in the formation of a duplicated body axis. Mesoderm induction as evaluated by the activation of the alpha-actin gene in presumptive ectoderm (animal cap) treated with exogenous activin was significantly enhanced by the injection of XSTK2 mRNA. These results suggest that the truncated receptor is capable of transmitting the activin signal to the same extent as the native receptor.

Actins↗
PubMed1992

Regulation mechanisms of intracellular pH of Xenopus laevis oocyte.

Intracellular pH values (pHi) of Xenopus oocytes were optically measured using a fluorescent dye, 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). The oocytes were loaded with dye by incubation with a membrane-permeable form (BCECF-AM). Mean pHi of the oocytes in pH 7.6 solution was 7.69. Increasing ambient pCO2 rapidly decreased pHi and estimated buffering power was 23.8 mM/pH unit. Changing ambient HCO3- from 5 to 30 mM did not alter pHi. After incubation in a Na(+)-free solution, Na+ addition to the bath rapidly increased pHi and this response was blocked by amiloride (ED50 2 microM). The addition of NH4Cl to the bath caused an initial transient increase in PHi followed by a secondary decrease. The secondary decrease was greatly inhibited by a histidine specific reagent, diethylpyrocarbonate. It was also slightly inhibited by ouabain, Ba2+ and furosemide, but not by amiloride. These data suggest that (1), fluorescence technique is applicable to PHi measurements of Xenopus oocytes; (2), Xenopus oocytes have an amiloride sensitive Na+/H(+)-exchange, and permeabilities to CO2, NH3, and NH+4. These observation may be useful in studying the relationship between pHi and oocytes development, and the expression of acid/base transporters in Xenopus oocytes.

Ammonia↗
PubMed1992

Mitochondrial tRNA(Ile) mutation in fatal cardiomyopathy.

A patient with mitochondrial encephalomyopathy who died from progressive intractable cardiac failure at the age of 18 is reported. At the age of 4, he presented with short stature, but multiorgan disorders including deafness, focal glomerulosclerosis, epilepsy and dilated cardiomyopathy appeared later in his clinical course. Laboratory tests showed hyperlactatemia and hyperpyruvatemia. Histopathological findings demonstrated mitochondrial myopathy with ragged red fibers and focal cytochrome C oxidase-deficient fibers in skeletal and cardiac muscles. The activity of cytochrome C oxidase was 30% less than the control level in skeletal muscle. Sequencing of the entire mitochondrial tRNA genome revealed a novel point mutation in the tRNA(Ile) region (nt 4269). This A-to-G substitution was found in none of the 30 controls by screening using mispairing PCR and Ssp I digestion methods, suggesting that this new mutation was pathogenic in our case.

Adolescent↗
PubMed1992

Changes in the nature of calcium transport systems on the porcine sperm plasma membrane during epididymal maturation.

Comparative studies of 45Ca(2+)-transport across the plasma membrane were performed using porcine caput, corpus and cauda epididymal sperm. The Ca(2+)-uptake is dependent on the presence of the substrates for respiration and is sensitive to verapamil. The Ca(2+)-efflux is mediated by both Na(+)-dependent and -independent systems. In the immature sperm in caput epididymis, Na(+)-independent efflux is predominant, but it is gradually replaced by Na(+)-dependent efflux during the epididymal transit. The net activity of Ca2+ accumulation into sperm increases with the epididymal maturation.

Animals↗
PubMed1992

Structure of the complement-activating proteoglycan from the pilose antler of Cervus nippon Temminck.

An anti-complementary polysaccharide, DWA-2, isolated from an unossified pilose antler of C. nippon Temminck by digestion with pronase, gel filtration, and affinity chromatography, consisted mainly of GalNAc, GlcA, IdoA, and sulfate in the molar ratios 1.0:0.6:0.3:0.8, and small proportions of Man, Gal, GlcNAc, and protein (4.5%). Methylation analysis, NMR spectroscopy, and degradation with enzymes indicated that DWA-2 contained chondroitin sulfate A-, B-, and C-like moieties. DWA-2 showed potent anti-complementary activity, and crossed immunoelectrophoresis indicated that it cleaved complement C3 in the absence of Ca2+ ion. Digestion of DWA-2 with chondroitinase ABC or ACI reduced the anti-complementary activity to a low level, but digestion with chondroitinase B reduced the activity by approximately 40% and the enzyme-resistant fraction still showed a significant activity.

Animals↗
PubMed1992

[A case report of serous cystadenoma located in pancreatic tail].

Cystadenomas of the pancreas are relatively rare compared to pseudocysts. There are two types of cystadenoma of the pancreas; mucinous and serous. Serous cystadenomas of the pancreas are very rare. We experienced a serous cystadenoma located in pancreatic tail. The patient was male, forty-one years old, and was free from any subjective symptom. The pancreatic cyst was found by abdominal ultrasonography and was difficult to differentiate serous or mucinous by computed tomography or celiac angiography preoperatively. We performed distal pancreatectomy and the cyst was revealed to be serous cystadenoma pathologically.

Adult↗
PubMed1992

Protein and nuclear changes in pig eggs at fertilization.

The nuclear restructuring that occurs between insemination and full pronuclear formation in pig eggs is accompanied by posttranslational changes to specific egg proteins. Sperm penetration begins in vitro at 3 hr postinsemination (hpi). By 5 hr, decondensing sperm heads and anaphase II plates are observed in 50% of eggs, and, by 8 hpi, both male and female pronuclei have formed. Three consistent changes to the pattern of newly synthesised proteins are triggered in this period; they affect the 46K, 25K, and 22K polypeptides. Changes are also triggered in the 180-200K polypeptides and in the 14K polypeptides, but these are highly variable. The same changes in the prefertilization pattern were observed when prelabelled eggs were used and new protein synthesis was suppressed. The first and most abrupt change involves the apparent catabolic elimination of a group of 46K unphosphorylated polypeptides (pl 7.3-6.4), whose synthesis was greatest before germinal vesicle breakdown but declined slowly in the final phase of maturation, then declined precipitously after activation. Ageing (beyond maturation) also leads to the disappearance of these polypeptides. The progressive disappearance of a set of 25K polypeptides and the concomitant appearance of a dominant 22K polypeptide is the most characteristic fertilization-induced modification to porcine egg proteins. These modifications begin within 1 hr of sperm penetration or activation, are specific to the pig, and involve heavily phosphorylated polypeptides (25K, pl 6.7-6.0) whose synthesis is begun in the early metaphase I stage. Dual ([35S] and [32P]) labelling, protein blocking experiments, and use of alkaline phosphatase suggest that dephosphorylation selectively affects these 25K polypeptides and is mainly or wholly responsible for converting them (completely within 6 hr) to a single, new (22K, pl 7.6) species that is positively charged. The 25K/22K polypeptide modification has a close temporal relationship with the formation of the male and female pronuclei.

Animals↗
PubMed1992

Intra-arterial administration of methotrexate, adriamycin, and cisplatin as neoadjuvant chemotherapy for bladder cancer.

As neoadjuvant chemotherapy for advanced bladder cancer, the intra-arterial administration of methotrexate (MTX), Adriamycin (ADM), and cisplatin (CDDP; IA-MAC) was evaluated. A total of 48 patients with bladder cancer (greater than or equal to T2 or CIS) were selected and received 30.1 mg MTX, 34.5 mg ADM, and 89.1 mg CDDP as an average course. The mean tumor-regression rate after 2 or 3 weeks was 52.3%, and patients with grade 3 transitional-cell carcinoma showed the best results, achieving a 69.6% regression rate. In 30 cases (63%), downstaging was observed. Among the 46 patients who underwent subsequent surgical therapy, the bladder could be preserved in 26 cases by transurethral resection or segmental resection. According to the criteria of the Japanese Association of Cancer Therapy, a histological effect of GIII or better was obtained in 15 cases (29%). The histological effect correlated well with the tumor-regression rate. As compared with intravenous therapy with MTX, vinblastine, ADM, and CDDP (M-VAC), IA-MAC treatment was well tolerated due to its lower degree of bone marrow suppression, and it resulted in a longer disease-free interval and better survival. In addition, the period prior to surgical therapy was shortened in this study. These results suggest that IA-MAC chemotherapy can be useful as an arm of multidisciplinary treatment of advanced bladder tumors.

Aged↗
PubMed1992

Fructose and glucagon loading in siblings with fructose-1,6-diphosphatase deficiency in fed state.

Hypoglycaemia induced by fructose administration is one of the diagnostic clues to fructose-1,6-diphosphatase (FDPase) deficiency (McKusick 229700). However, the pathological mechanism of this reactive hypoglycaemia is not fully known. This paper describes two siblings with FDPase deficiency, diagnosed enzymatically in leukocytes, who failed to correct reactive hypoglycaemia after glucagon administration even in the fed state, supporting a possibility that disturbed hepatic phosphorylase activity may be a main cause of reactive hypoglycaemia.

Blood Glucose↗
PubMed1992

In vivo anti-influenza virus activity of plant flavonoids possessing inhibitory activity for influenza virus sialidase.

Isoscutellarein (5,7,8,4'-tetrahydroxyflavone) from the leaf of Scutellaria baicalensis non-competitively inhibited (IC50, 20 microM) the hydrolysis of sodium p-nitrophenyl-N-acetyl-alpha-D-neuraminate by influenza virus sialidase with an apparent Ki value of 41 microM. Negligible inhibitory activity was observed for mouse liver sialidase at a concentration of 79 microM. Isoscutellarein also inhibited the replication of influenza virus A/WSN/33 in Madin-Darby bovine kidney cells with 50% virus inhibitory dose at 16 nmol/well and influenza virus A/PR/8/34 in the allantoic sac of embryonated egg with little toxic effects. The flavone showed significant anti-influenza virus activity in vitro similar to isoscutellarein-8-methylether (F36) (Nagai, T., Miyaichi, Y., Tomimori, T., Suzuki, Y. and Yamada H., 1990, Chem. Pharm. Bull. 38, 1329-1332), and more potent virucidal activity in ovo than F36. However, F36 completely prevented proliferation of mouse-adapted influenza virus A/PR/8/34 in mouse lung by the intranasal (0.5 mg/kg) and intraperitoneal (4 mg/kg) administrations, and it was more potent than the known anti-influenza virus substance, amantadine. Intranasal administration of F36 (0.5 mg/kg) also protected mice against a lethal influenza virus A/PR/8/34 infection. Isoscutellarein significantly inhibited lung virus proliferation when administered intranasally or orally to mice. F36 and isoscutellarein showed negligible toxic effect against mice. These results suggested that flavones, which have potent influenza virus sialidase inhibitory activity, have anti-influenza virus activity in vivo.

Animals↗
PubMed1992

Infantile polymyositis: a case report.

A 10-month-old Japanese boy developed progressive muscle weakness and hypotonia at 3 months of age. Because of striking inflammatory cellular infiltration in his muscle biopsy, he was diagnosed as having infantile polymyositis and was placed on steroid and immunosuppressive medication when he was 10-month-old. His physical condition was not significantly altered, though serum creatine kinase (CK) level was normalized (1,500 iu/l----90 iu/l). These findings contrast with previous reports documenting improvement with steroid administration.

Adrenal Cortex Hormones↗
PubMed1992

A novel method to analyse response patterns of taste neurons by artificial neural networks.

Despite several notions on the gustatory code proposed over three decades, investigators have not yet reached a consensus. This paper describes a new approach to analyse gustatory neural activities. Three-layer neural networks were trained by the back-propagation learning algorithm, to classify the neural response patterns to four basic taste qualities. The discrimination by the trained networks on taste qualities in the response patterns of rat chorda tympani fibres (CT) and cortical taste neurons (CN) was consistent both with the correlation analysis and with behavioural experiments. By examining the connection weights of each neuron, some input neurons representing CN were 'pruned' without deteriorating the ability of the network to discriminate taste. This characteristic of the network is contrary to a previous hypothesis, that taste neurons are of equal importance in the neural coding.

Animals↗
PubMed1992

Anti-reflux surgery by injection of Teflon paste.

Over a 3-year period, 55 refluxing ureters in 36 patients were treated by the endoscopic injection of Teflon paste. Although reflux was corrected immediately in 54 ureters (98%), reflux recurred 3 to 4 months later in 18 ureters. Reinjection was carried out once in 5 ureters and twice in 1. The success rate was 71% in primary reflux and 53% in secondary reflux. Significant side effects were encountered post-operatively in 3 patients: vesicoureteric junction obstruction in 2 and urethral stricture in 1. We recommend that the results of surgery should not be evaluated until at least 3 to 4 months after operation. A review of the literature shows that the overall success rate was 92% in 367 ureters with primary reflux and 70% in 181 ureters with secondary reflux. Because of the uncertain outcome of surgery and the possibility of adverse side effects, one should be cautious when considering this form of treatment in young children.

Adolescent↗
PubMed1992

The influence of detergents on skin barrier properties.

The influence of surfactants on the changes in skin barrier properties was investigated in rats. Various ionic and non-ionic surfactants were assessed using indomethacin as a model penetrant. The surfactants appeared to either increase or decrease the skin permeability, due to the properties of both compound and surfactant. Ionic surfactant sodium dodecylsulfate was the most powerful and exceeded controls by approximately 10 times measured by means of serum levels of indomethacin. Other surfactants caused concentration increase or decrease of indomethacin in serum.

Administration, Cutaneous↗
PubMed1992

[Quantitative analyses of the normal throat flora of children with upper respiratory tract infections].

Relationship between the normal throat flora and pathogenic bacteria recovered from the throat in 139 children with upper respiratory tract infections in winter were studied using quantitative analyses. Pathogenic bacteria examined include S. pyogenes, H. influenzae, S. aureus, and S. pneumoniae, and the normal floras include alpha-streptococci, gamma-streptococci, Neisseria species, and Micrococci. Children with S. pyogenes in their throats (S. pyogenes group) were examined with anti-streptococcal antibodies such as anti-streptolysin O, anti-streptokinase, and anti-deoxyribonuclease B. Eighty seven pathogenic bacteria were recovered from 72 children (51.8%) out of 139. S. pyogenes and S. pneumoniae groups showed significantly lower alpha-streptococci and gamma-streptococci in incidence of appearance when compared with children with the no pathogenic bacteria in their throats (no bacteria group). H. influenzae group showed significantly lower gamma-streptococci and higher Neisseria sp. in incidence of appearance compared with the no bacteria group. Positive cases for anti-streptococcal antibodies showed a significantly lower alpha-streptococci in number compared with negative cases for antibodies and the no bacteria group, and a significantly lower gamma-streptococci in incidence of appearance compared with the no bacteria group. These data suggest that the normal throat flora may have a role in prevention of colonization by the pathogenic bacteria in vivo, as were shown in vitro by many authors, and that the quantitative analysis of the normal flora is useful because this methodology might reveal whether the bacteria recovered from the throat show the pathogenicity.

Adolescent↗
PubMed1992

[Detection and serotyping of HRVs collected from children with acute gastroenteritis in winter of 1986 to 1991].

Fecal samples from sporadic acute gastroenteritis patients who visited at a pediatrician during five consecutive winter seasons in Kurume City located at north part of Kyushu district. Fecal samples were subjected to detection of rotavirus and other viruses and study of yearly changes in serotype of rotavirus. The rate of group A rotavirus positives in third winter and other consecutive winters were 12.5%, 40 to 65%, respectively. 60% specimens were successfully serotyped: 58% was serotype 1.22% was serotype 3.6% was serotype 2, and 14% was serotype 4. The dominant serotype in first, fourth and fifth winter was type 1. However in second winter each serotype of rotavirus was almost equally detected. During five consecutive winters six patients visited at the same pediatrician twice more than two months interval. They all had acute gastrointestinal symptoms. In six patients rotavirus was detective just once.

Acute Disease↗