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Biomedical subjects

T Nagata

Publications and source records attributed to T Nagata.

At least 271 records · Page 15Linked to original sources

A light and electron microscopic radioautographic study on RNA synthesis in the retina of chick embryo.

The incorporation of 3H-uridine into RNA of chick embryo retina was studied by light and electron microscopic radioautography. The numbers of silver grains were counted over the nucleus, nucleolus and cytoplasm of the cells in three different regions of the same retina of 2, 3, 4, and 7 day chick embryos. The results showed an increase of 3H-uridine incorporation from embryonic day 2 to 7. In every stage of development of the chick embryo retina, the number of silver grains was higher in the anterior than in the other two regions of the retina. In the three cell compartments of every embryo group, the number of silver grains was higher in the nucleus than in the nucleolus and cytoplasm. The results show further that the grains were less in the cytoplasm of the retinal cells of the day 2 embryo group and higher in the other groups especially in the day 7 embryos. Ultrastructural changes were also observed during the studied period of retina development.

Animals↗

Isolation and characterization of a TATA-less promoter for the human RAG-1 gene.

Human recombination activating gene-1 (RAG-1) genomic DNA clones containing the first exon coding for the 5' untranslated region and the second exon coding for the remaining 5' untranslated region, coding region, and 3' untranslated region were cloned. Primer extension analysis and RNase protection analysis demonstrated the multiple RAG-1 transcription start sites, clustered in a 31 nucleotide (nt) region. Sequence analysis showed that the RAG-1 promoter lacked a TATA box as well as an initiator sequence. Transient expression assays using a luciferase reporter gene with truncated promoter fragments and substitution mutants, showed that the 5' promoter region containing the CCAAT box between -110 and -86, is indispensable for its basal promoter activity in RAG-1 expressing Nalm 6 cell line. Comparative transient expression assays in various cell lines revealed that the 854 nt upstream promoter region was active, not only in RAG-1 expressing cell lines but also in RAG-1 non-expressing cell lines. These data indicate that the 854 nt upstream region of RAG-1 gene confer basal promoter activity, and that the tissue- and stage-specific expression of RAG-1 is controlled by elements present outside of the promoter region and/or differential chromatin structure(s) of the individual cells.

Base Sequence↗

Outbreak of multi-drug resistant Staphylococcus aureus: a cluster analysis.

BACKGROUND: Outbreaks of multi-drug resistant Staphylococcus aureus over eight years were investigated to prevent future endemic. METHODS: Isolates of multiresistant S. aureus underwent a cluster analysis combined with canonical discriminant analysis using bacteriologic biotyping and sensitivity to 21 drugs. RESULTS: Of a total of 786 strains recovered from 155 in-patients, the specialty surgical ward (SW) exhibited 470 isolates (59.8%) and the general SW 214 (27.2%). Among six clusters formed, four clusters were predominant in the general SW. An ordination diagram from the canonical discriminant analysis revealed a distribution in which clusters were localized temporally (year) and spatially (ward). A yearly shift of clusters indicated emergence of a new phenotype of multiresistant S. aureus. CONCLUSIONS: The cluster analysis of isolates of multiresistant S. aureus using biotyping and sensitivity may supplement the classical method of tracing the spreading patterns of this microbe.

Anti-Bacterial Agents↗

Prevalence of cavum septum pellucidum detected by MRI in patients with bipolar disorder, major depression and schizophrenia.

The incidence of cavum septum pellucidum (CSP), which has been widely regarded as a developmental anomaly of little clinical importance in neuropathology, was examined in 113 patients with affective disorders (69 with bipolar disorder and 44 with major depression), 40 schizophrenic patients, and 92 control subjects by magnetic resonance imaging (MRI). Significantly higher incidence of Grade 3-4 CSP (moderate to large) compared with the controls was found only in the schizophrenics. When a broader interpretation of CSP, including indeterminant (Grade 1) and small (Grade 2) CSP was used, three additional patients with bipolar disorder were found to have Grade 1-2 CSP, and the total prevalence of Grade 1-4 CSP in the patients with bipolar disorder was significantly higher than that in the control subjects but slightly lower than that in the schizophrenic patients. CSP was not observed in any patient with major depression. There were no differences between the patients with and without CSP in age, sex, education, or the duration of illness. These findings are consistent with the hypothesis that neurodevelopmental abnormality may be present in schizophrenia, and such an abnormality may also be present in some patients with bipolar disorder.

Adult↗

Developmental expression of the Bombyx Antennapedia homologue and homeotic changes in the Nc mutant.

BACKGROUND: Abundant availability of homeotic mutants in Bombyx mori provides us with clues to study the body plan of the silkworm. Previous studies indicated that the ECa/ECa and EN/EN embryos, which reveal drastic morphological changes (Itikawa 1943, 1952) lack the homologue of abd-A and the homologues of abd-A and Ubx, respectively (Ueno et al. 1992). It will be interesting to characterize a mutant named Nc, the locus of which was mapped about 1.4 cm apart from the E loci (Itikawa 1944, 1952). RESULTS: In the present study we cloned and identified the Bombyx Antennapedia cDNA from a library of larval middle silk gland. The developmental expression patterns of the Bombyx Antennapedia were analysed in embryos and larval middle silk glands. We found the Bombyx Antennapedia mRNA of the Nc mutant lacks the homeobox region and its downstream region. This defect comes from a corresponding deletion on the Nc chromosome. Development of the Nc/Nc embryos terminates at stage 26, revealing a transformation of the prothoracic legs into antennae, milder changes in the mesothoracic legs, compression between the prothoracic and mesothoracic segments as well as in the gnathocephalon region, and a severe growth suppression of the silk glands. CONCLUSIONS: These results give a molecular basis and detailed morphological abnormalities of the Nc mutant known since 1944.

Amino Acid Sequence↗

Ubiquitin-like polypeptide inhibits the IgE response of lipopolysaccharide-activated B cells.

Monoclonal non-specific suppressor factor (MNSF), a lymphokine produced by a murine hybridoma, was originally found to inhibit the generation of lipopolysaccharide (LPS)-induced Ig-secreting cells. Most recently, we demonstrated the recombinant form of the ubiquitin-like segment (rUbi-L) or MNSF beta, an isoform of MNSF, has a MNSF activity. To investigate the possible role of rUbi-L, a 8.5 kDa ubiquitin-like polypeptide, in the regulation of Ig isotype secretion, rUbi-L was added to purified B cell cultures stimulated with LPS plus IL-4. rUbi-L notable suppressed the IgE and IgG1 responses when added at culture initiation. In addition, rUbi-L had a strong effect on IgG3 production and a little effect on IgM production by LPS-stimulated B cells, whereas the level of other isotypes (IgG2a, IgG2b and IgA) was not affected. These findings demonstrate the isotype-specific suppression, but not pan-suppression, of Ubi-L. IFN-alpha and IFN-gamma, which are also known to inhibit the IgE response, showed a synergistic effect with Ubi-L, albeit the effects of IFN-alpha were smaller. The action was reversed by the addition of neutralizing antibodies of these cytokines. Therefore, Ubi-L, a ubiquitin-like protein, may have an important immunoregulatory role on the IgE response.

Animals↗

The mode of expression and promoter analysis of the arcA gene, an auxin-regulated gene in tobacco BY-2 cells.

The arcA, a member of the G protein beta-subunit family, was isolated from tobacco BY-2 cells as an auxin-responsive gene. Characterization of arcA, which should help to elucidate the function of the gene product in the plant cells, was performed with emphasis on the mode of expression and the analysis of its promoter. Accumulation of the arcA message was detected only after treatments with auxins and not after treatments with other phytohormones or CdCl2, implying that responsiveness of arcA was exclusive to auxin. The putative arcA promoter region was fused to a reporter gene for beta-glucuronidase (GUS), and transient expression was analyzed in tobacco BY-2 cells. Two series of arcA promoter/GUS chimeric genes were constructed. One consisted of a set of 5' nested deletions of the arcA promoter connected to the gene for GUS and the other consisted of a variety of the arcA promoter fragments fused to a minimal promoter-GUS construct. The results indicated that the promoter sequence covering four sets of direct repeats (-562 to -167) was necessary for the sufficient response of arcA promoter to auxin in BY-2 cells. Moreover, irrespective of auxin treatment, elevated activity of GUS driven by this promoter fragment was detected, a result that implies that this region behaves an enhancer in BY-2 cells.

Base Sequence↗

Analysis of the promoter of the auxin-inducible gene, parC, of tobacco.

The auxin-responsive region (AuxRR) in the promoter of the parC gene was analyzed in transgenic tobacco plants in which the 5' flanking region of the parC promoter was placed upstream of the gene for beta-glucuronidase (GUS). The AuxRR was located between nucleotides (nt) -226 and -54. Detailed dissection of this segment revealed that the presence of the non-contiguous sequences from nt -226 to -151 and from nt -84 to -54 was required for the expression of the auxin responsiveness of the parC promoter. The sequence from nt -226 to -151 was found to contain a sequence which resembles the as-1 element in the 35S promoter of cauliflower mosaic virus (CaMV). Although it has been reported that the as-1 element is involved in auxin responsiveness [Liu and Lam (1994) J. Biol. Chem. 269: 668], we showed that introduction of a point mutation into the as-1-like sequence completely eliminated auxin responsiveness, a result that suggests that the sequence is indispensable for auxin responsiveness. However, the presence of the as-1-like sequence alone was not sufficient for auxin responsiveness, since the segment (nt -226 to -84) that included the as-1-like sequence failed to confer auxin responsiveness on the core promoter. It is possible that the two separately located sequences play specific roles in interactions with trans-factors that are required for the expression of the auxin responsiveness of the parC promoter.

Base Sequence↗

A multiple-stimuli-responsive as-1-related element of parA gene confers responsiveness to cadmium but not to copper.

The expression of parA, an auxin-regulated gene expressed during the culture of tobacco (Nicotiana tabacum L.) mesophyll protoplasts, is induced by cadmium. To identify the cadmium-responsive element, we examined the parA promoter using the GUS reporter gene. Cadmium responsiveness was retained in a 5' deletion of the parA promoter to -78 bp, but it was nullified by further deletion to -49bp, which implies that the region -49 to -78 bp contained a cadmium-responsive element. This region contains a sequence similar to as-1, an enhancer sequence from the cauliflower mosaic virus 35S RNA promoter that binds the nuclear factor ASF-1. We named the sequence in the parA promoter pas. Gel-shift assays revealed that pas and as-1 compete for the same DNA-binding nuclear protein(s). Since pentamers of either pas and as-1 were able to confer cadmium responsiveness on a minimal promoter but mutant as-1 was not, we propose that pas and as-1 are involved in cadmium-responsive gene expression. Neither pas nor as-1 conferred responsiveness to copper. The specificity of this response, involving the function of as-1-related elements including pas, is discussed.

Base Sequence↗

Married patients with eating disorders in Japan.

A total of 40 married and 22 unmarried female patients with eating disorders were studied in order to investigate the relationship between eating disorders and marriage. Eating disorders developed in 14 patients before marriage (premarital onset) and in 26 patients at the time of or after marriage (postmarital onset). The postmarital-onset group was characterized by a significantly higher age at onset, but was similar in age and duration of illness to the group of 22 unmarried patients. However, the various clinical features of the three groups did not differ. For premarital-onset patients showed exaggerated clinical features after marriage, but the other patients showed no change in clinical features after marriage. In the postmarital-onset group, eating disorders were triggered in 18 patients (69%) by marital problems, separation or divorce. In contrast, eating disorders were triggered by dieting in order to lose weight in 8 patients (57%) in the premarital-onset group and 12 patients (55%) in the unmarried group. These results suggest that marital conflict plays an important role in the development and continuation of eating disorders in married women.

Adult↗

Multicopy suppressors of the cold-sensitive phenotype of the pcsA68 (dinD68) mutation in Escherichia coli.

The Escherichia coli strain cs2-68 is a cold-sensitive (c) mutant that forms a long filamentous cell at 20 degrees C with a large nucleoid mass in its central region. We have recently shown that the pcsA68 mutation causing the cs phenotype is a single-base substitution within the dinD gene, a DNA damage-inducible gene which maps at 82 min. Since null mutants of the pcsA (dinD) gene are viable, with no discernible defect in cell growth, the cs phenotype is attributed to a toxic effect by the mutant protein. In an attempt to identify a target(s) for the toxic pcsA68 mutant protein, we screened for chromosomal fragments on multicopy plasmids that could suppress the cs phenotype. Three different BamHI fragments were found to suppress cold sensitivity, and the lexA, dinG, and dinI genes were identified to be responsible for the suppression in each fragment. DinG shares multiple motifs with many DNA helicases. The complete sequence of dinI revealed that DinI is a small protein of 81 amino acids. It is similar in size and sequence to ImpC of the Salmonella typhimurium plasmid TP110 and to a protein (ORFfs) of the retronphage phi R67, both of which are also under the control of LexA.

Amino Acid Sequence↗

Differential subcellular localization of neural isoforms of the catalytic subunit of calmodulin-dependent protein phosphatase (calcineurin) in central nervous system neurons: immunohistochemistry on formalin-fixed paraffin sections employing antigen retrieval by microwave irradiation.

We examined the immunohistochemical distribution of the two mammalian isoforms of calcineurin catalyic subunits, A alpha and A beta, in central nervous system (CNS) tissues of cows, rats, and humans. Cryostat sections and paraffin sections of parformaldehyde-fixed tissues were stained with antipeptide antibodies for each isoform. The same localization pattern was observed in both cryostat and paraffin sections. In the latter, the intensity of the staining was dramatically enhanced by microwave irradiation. Calcineurin isoforms were localized in a variety of nerve cells but not in neuroglial cells. Their differential expression as the A alpha isoform in the nucleus and the A beta isoform in the cytoplasm was present in a variety of CNS nerve cells, most distinctively in Purkinje cells of the cerebellum and pyramidal cells of the cerebrum, irrespective of species. These results suggest that each isform has distinct intracellular sites of action in CNS neurons and that the phenomenon has been conserved during mammalian evolution.

Amino Acid Sequence↗

Pathogenesis of drug-induced gingival overgrowth. A review of studies in the rat model.

Drug-induced gingival overgrowth is a side effect associated principally with 3 types of drugs: anticonvulsant (phenytoin), immunosuppressant (cyclosporine A), and various calcium channel blockers (nifedipine, verapamil, diltiazem). In this review, we describe the features of phenytoin-, cyclosporine A- and nifedipine-induced gingival overgrowth in rats and discuss factors influencing the onset and severity of these disorders. There are several features common to the gingival overgrowth induced by these drugs: 1) gingival overgrowth is more conspicuous in the buccal than in the lingual gingiva and less severe in the maxilla than in the mandible; 2) once the blood concentration of the drug reaches a certain level as a result of increasing the dose, the incidence of gingival overgrowth is 100% and its severity is dependent on the blood level, the most severe overgrowth being induced by cyclosporine A; 3) the duration of drug administration for maximal gingival overgrowth to develop is about 40 days; 4) the gingival overgrowth regresses spontaneously after discontinuing the drug; 5) accumulation of dental plaque is not essential for the onset of overgrowth, but plays a role in its severity; and 6) more severe overgrowth is induced in young than in old rats. Furthermore, male rats are more susceptible than females to nifedipine-induced gingival overgrowth. These results suggest that drug-induced gingival overgrowth in rats is dependent on the oral drug dose, blood drug level, age, and sex and that preexisting gingival inflammation is a factor relevant to its severity. Since these factors have also been suggested to be important determinants for human drug-induced gingival overgrowth, the rat model may prove valuable in the future for elucidating the molecular pathogenesis of the disorder.

Age Factors↗

[Indication for surgery of pediatric testicular and funicular hydroceles in view of natural course].

PURPOSE: The purpose of this study is to confirm the definite indication for surgery of pediatric testicular and funicular hydroceles in view of natural course. METHODS: During the period from 1978 to 1994, we encountered 160 hydroceles in 149 pediatric patients. Patients ages ranged from 5 days after birth to 13 years and the mean follow-up periods was 4.7 years. We investigated the indication for surgery of pediatric hydroceles in six points of view: value of an aspiration of hydroceles, of what testicular or funicular or both, communication, size, age and testicular development. RESULTS: Nevertheless, of 160 hydroceles, 66 (41%) were performed an aspiration of hydroceles, the aspiration of hydrocele was ineffective in the majority of patients. Common hydroceles in neonates and infants required no specific treatment, as the majority of hydrocele resolve spontaneously, however surgical treatment was required for a communicating large hydrocele that had been often attacked by aspiration and appeared at older age. Funicular hydroceles were more difficult to spontaneous healing. Ipsilateral testis manifests a well-developed comparing control material. CONCLUSION: The indication for surgery of pediatric hydroceles were as follows: 1) hydroceles complicated by a inguinal hernia or cryptorchidism, 2) hydroceles appeared at older age and not resolved during 2-3 years over, 3) giant communicating funicular and testicular hydroceles present with an/hindrance for daily life.

Child↗

Brain death diagnosed by forensic analysis of drug distribution in human tissues-II--Distribution of caffeine in brain dead patients.

Caffeine concentrations in human tissues of 6 brain death cases as well as 5 non-brain death cases were examined in order to assess the possibility of diagnosing brain death based on an analysis of this compound. Concentrations of caffeine in human tissues were determined using gas chromatography/mass spectrometry. The tissue-to-blood concentration ratios were used to evaluate the distribution pattern in each case. In non-brain death cases, the ratios in all examined tissues were similar, and the values were close to 1 in all tissues except adipose, of which the value was near 0.3. In brain death cases, the ratios in all tissues except brain and adipose were similar to those in non-brain death cases. The ratios in the brain were higher than those of non-brain death cases, in 5 brain death cases, and lower in 1 brain death case to whom blood transfusion was done in a hospital. The ratios in the adipose were slightly higher in brain death cases than those in non-brain death cases. The discorded distribution of caffeine in brain death cases was presumably related to cessation of cerebral blood circulation at the time of brain death. Therefore, comparing caffeine concentrations in the brain with those in the other tissues can be useful for a forensic diagnosis of brain death.

Adult↗