PubMed Health⌕ Search

Biomedical subjects

Y Nakatani

Publications and source records attributed to Y Nakatani.

At least 19 recordsLinked to original sources
PubMed1992

Identification of human TFIID components and direct interaction between a 250-kDa polypeptide and the TATA box-binding protein (TFIID tau).

Previous studies have indicated that human transcription initiation factor TFIID is a large complex that contains a TATA-binding polypeptide (TFIID tau or TBP) and other components that qualitatively alter promoter interactions and are uniquely required for activator-dependent (versus basal) transcription. TFIID tau-specific antibody columns have been employed to identify a number of human TFIID polypeptides that are tightly associated with TFIID tau. These differ in size from polypeptides in known general initiation factors, including the initiator-binding factor (TFII-I) which shares some promoter binding characteristics with TFIID. The largest component (p250) identified in TFIID was shown to interact directly and tightly with TFIID tau, suggesting that it may play a major role in the assembly of the TFIID complex.

DNA-Binding Proteins↗
PubMed1992

The interaction of various cholesterol 'ancestors' with lipid membranes: a 2H-NMR study on oriented bilayers.

The effect of putative cholesterol 'precursors' on model membranes has been studied by deuterium nuclear, magnetic resonance (2H-NMR) spectroscopy. Oriented bilayers were prepared from 1-myristoyl-2-[2H27 myristoyl-sn-glycero-3-phosphocholine (DMPC-d27) and tricyclohexaprenols or octaprenediols. Order parameter profiles were determined and showed that tricyclohexaprenols and octaprenediols increase the acyl chain order in DMPC bilayers, but to a smaller extent than cholesterol. The order parameter increases, depending on the chain position, from 5% to 7% in the presence of ditertiary octaprenediol, and from 16% to 21% in the presence of tricyclohexaprenol-Z,Z. Aqueous multilamellar dispersions of DMPC-d27 and of DMPC-d27 containing 30 mol% tricyclohexaprenol-E,E were prepared, and the first moments calculated from 2H-NMR spectra over the temperature range 5-55 degrees C. Tricyclohexaprenol-E,E almost abolishes the phase transition of DMPC. Thus, as predicted, tricyclohexaprenols and octaprenediols have a cholesterol-like behaviour in lipid membranes; however their effect on the model DMPC system is weak. On the contrary, isoarborinol has no effect on the lipid chain order in the liquid-crystalline phase of DMPC bilayers. 2H-NMR spectra of aqueous dispersions of DMPC-d27 and 30 mol% isoarborinol between 25 and 60 degrees C showed the coexistence of two lamellar phases over a wide temperature range, which was confirmed by differential scanning calorimetry (DSC) and 31P-NMR spectroscopy. This absence of ordering effect of isoarborinol might be related to some inherent structural features.

Alcohols↗
PubMed1992

Isolation and characterization of a cDNA encoding Drosophila transcription factor TFIIB.

A Drosophila cDNA encoding a human transcription factor TFIIB homologue was isolated by PCR methods. The deduced amino acid sequence indicates 85% sequence similarity with human TFIIB, and the corresponding cDNA product expressed in Escherichia coli is interchangeable with human TFIIB for both basal and GAL4-VP16-induced transcription. Structural motifs including the direct repeats, basic repeats, and sigma sequence similarities are well conserved among Drosophila, human, and Xenopus TFIIB. However, the N-terminal region of each direct repeat is less conserved among the three species, suggesting the presence of two structural subdomains in the direct repeat. Moreover, the amino acid changes in the N-terminal subdomain produce altered positions of the conserved amino acids between the direct repeats. An overall similarity in general structural features between TFIIB and TFIID tau (the TATA-binding subunit of TFIID) was previously noted. However, in contrast to the sequence divergence reported for the N-terminal domains of TFIID tau from different species, the N-terminal sequence of TFIIB was highly conserved among the species. This suggests that TFIIB has a more rigid structure, consistent with its function as a "bridging" protein between TFIID and RNA polymerase II. Further implications of the TFIIB structure are discussed.

Amino Acid Sequence↗
PubMed1992

An autopsy case of renal cell carcinoma associated with extensive peliosis hepatis.

An autopsy case of renal cell carcinoma with extensive peliosis hepatis is reported. The patient was a 34-year-old female, who had had a left nephrectomy for renal cell carcinoma but died of multiple metastases one year and 4 months after surgery, despite chemotherapy and interferon treatment. At autopsy, the liver was enlarged markedly with multiple metastatic nodules and the non-neoplastic hepatic parenchyma had a spongy appearance, due to diffusely scattered, blood-filled cystic lesions. Histological examination showed the oval to irregular shaped blood-filled spaces were lined by hepatic cell cords and located mainly in the periportal area. In addition, almost all of the sinusoids were dilated and communicated with the cystic blood-filled spaces, which also communicated directly with branches of the portal veins at various levels. Several interlobular portal branches were obstructed. The causative mechanism of peliosis hepatis has yet to be elucidated, although some causative conditions have been proposed. In this case, renal cell carcinoma may have caused the sinusoidal dilatation and the vascular changes in the portal areas, such as obstruction of terminal portal branches, may have contributed to its formation.

Adult↗
PubMed1992

[Adult T-cell leukemia with various pulmonary complications].

A 59-year-old male, born in Wakayama prefecture, was admitted to our hospital because of cervical lymph node swelling, huge mass lesions in both liver and head of the pancreas, and multiple nodular shadows in the left lung. Lymph node biopsy revealed a necrotic lesion containing tuberculous bacilli with no epithelioid cells or giant cells. Adult T-cell leukemia (ATL) was diagnosed by the presence of atypical lymphocytes with a convoluted nucleus and positive anti-ATL antibody. During successful treatment of Mycobacterium tuberculosis with ethambutol, isoniazid and rifampicin, ATL transformed to the blastic phase. The new pulmonary infiltrates improved after treatment with both combination chemotherapy for ATL and antibiotics. However, new infiltrative shadows appeared in both lungs, and were resistant to treatment and the patient died of acute respiratory failure. Histological examination of the lung at autopsy showed interstitial fibrosis with infiltration of leukemic cells and cytomegalovirus infection.

Cytomegalovirus Infections↗
PubMed1992

Compensatory angiogenesis during progressive right ventricular hypertrophy.

We investigated vascular adaptations occurring in progressive right ventricular hypertrophy (RVH) in adult mini pigs. Fourteen mini pigs had progressive RVH induced by implanting an inflatable cuff on the main pulmonary artery for 1-5 months and were compared to a control group (N = 11). RVH animals were divided into two groups, a moderate RVH (MH) that had RV/BW ratio increases of 20%-70% above controls and a severe hypertrophy group (SH) that had RV/BW ratio increase of 70%-117%. We measured coronary blood flow reserve (CBFR) with radiolabelled microspheres at maximal exercise and during adenosine vasodilation. Adenosine vasodilation did not decrease CBFR either regionally or transmurally in both the MH and SH groups. During exercise CBFR showed a small but significant decrease in the SH group. No intervention changed the endo/epi flow ratios. Morphometric studies showed that myocytes increased in cross sectional areas (CSA) in these hypertrophied hearts. The CSA of capillaries and arterioles and their numerical densities increased significantly in the endocardial and epicardial regions in both MH and SH groups. Capillary density showed a small but significant decrease in both MH and SH groups. We measured DNA synthesis in these hearts using tritiated thymidine labelling. We found a high labelling index in endothelial cells and a moderate labelling index in smooth muscle cells in early stages of hypertrophy. These data show that angiogenesis, observed in the morphometric studies and by DNA labelling, prevents CBFR changes during progressive RVH in the pig. Furthermore, angiogenesis is not uniform at different stages of progressive RVH.

Adaptation, Physiological↗
PubMed1992

[Expression of epidermal growth factor receptor in adult human airway epithelium--application of AMeX method].

To elucidate the role of epidermal growth factor (EGF) in the maintenance and repair of airway epithelial cells in adult humans, we investigated immunohistochemically whether EGF receptor (EGFR) is expressed in these cells. In the present study, we employed the AMeX method (Sato et al., 1986) for tissue preparation. We first examined the expression of EGFR in peripheral lung tissue and bronchial tissue obtained at surgery from thirteen adult patients with lung carcinoma. The results showed that there was no positive staining for EGFR in the bronchial surface epithelium, bronchial glandular cells, bronchiolar epithelium or alveolar lining cells. There was also no expression of EGFR in cells comprising areas of basal cell hyperplasia and epidermoid metaplasia in the bronchus, or alveolar cell hyperplasia and columnar cell metaplasia in fibrotic lung tissue. Second, we examined the expression of EGFR in regenerating distal airway epithelial cells, which were experimentally produced by xenotransplantation of human lung tissue into the subcutaneous tissue of nude mice. There was also no expression of EGFR at any stage of regeneration from one week through six weeks after the transplantation. It is concluded that EGFR is not expressed, at least at an immunohistochemically detectable level, by airway epithelial cells of adult humans, not only in the quiescent state but also under conditions in which epithelial cells are stimulated to replicate. Thus, it appears unlikely that the EGF/EGFR system plays an important role in either maintenance or repair of airway epithelial cells in adult humans.

Adult↗
PubMed1991

Multiple interacting sites regulate astrocyte-specific transcription of the human gene for glial fibrillary acidic protein.

The gfa gene encodes glial fibrillary acidic protein, an intermediate filament protein found almost exclusively in astrocytes. Transient transfection studies with a chloramphenicol acetyltransferase reporter gene were used to identify regions of the gfa gene responsible for its expression. Three regions, A, B, and D, were found to be important. The D region is located near the basal promoter, while A and B are next to each other about 1500 bp further upstream. The regions contain several sequences homologous to binding sites of known transcription factors, and in addition, each contains an identical novel 10-bp motif. The A, B, and D regions act in a cell-specific manner; when joined to the SV 40 early promoter, they enhance transcription in the glial cell line U251, but not in the nonglial cell line HepG2. Consistent with this observation, the DNase I footprint produced in these regions by nuclear extract from U251 cells differs from that produced by an extract from HepG2 cells. The B region appears to be the most active of the three, as by itself it stimulates strong cell-specific transcription, whereas addition of the other two regions has little effect. When the B region is at its normal distance from the basal promoter, deletion of D severely reduces transcription, but when B is placed near the promoter, D is unimportant. This suggests that the D region may function primarily to promote interactions that bring B close to the promoter.

Astrocytes↗
PubMed1991

[A study of family support, health state and medical care among functionally dependent elderly in Shanghai, China].

The effect of family caregiver's attitudes to elderly on health conditions of functionally dependent elderly, relationships between family support and perceived burden among family caregivers, and factors related to family support were analyzed. Support in this study was defined as help directed at helping functionally dependent elderly achieve independence or self-care. In 1989, a survey was conducted of family caregivers in Shanghai. Functionally dependent elderly were collected by screening of people aged 65 years old and over, and family caregivers who were able to provide support as defined above were included as subjects (n = 468). The following results were obtained: 1. Caregivers with positive attitudes for support had a higher proportion having the ability to obtain physician care compared to those with low family support. The proportion of persons with bedfast condition, cognitive impairment, and abnormal behaviors did not appear to have a relationships to level of family support. 2. There was only a weak relation between family support and perceived burden scale of caregivers. 3. Among all factors, the strongest relationship to family support was with educational background. The health of caregivers and the family relationship between caregivers and functionally dependent elderly were also related to level of family support.

Aged↗
PubMed1990

A downstream initiation element required for efficient TATA box binding and in vitro function of TFIID.

The gfa gene encodes glial fibrillary acidic protein, an intermediate filament protein expressed in glial cells. In vitro transcription analysis has shown that the human gfa promoter contains two initiation elements that can independently specify the transcription startpoint. One of the elements is a TATA box 25 base pairs (bp) upstream from the transcription startpoint; the other is located between 10 and 50 bp downstream from the transcription initiation site. We have now shown by transfection that both elements are required for efficient transcription in cultured cells. A partially purified natural human TATA box-binding factor (TFIID) from HeLa cells gave footprints that extended from upstream of the TATA box through the downstream initiator. Deletion of the downstream initiator inhibited both TFIID binding to the TATA box and transcription in vitro. In contrast to natural human TFIID, clone human and yeast TFIIDs expressed in bacteria gave footprints covering only the TATA box region, although hypersensitive sites were observed in the downstream region. The cloned TFIIDs also showed less dependence than natural human TFIID on the downstream initiator for both TATA box binding and in vitro transcription. These results suggest that natural human TFIID contains an additional component(s) that contribute(s) to stable TFIID binding and effective transcription by interacting with the downstream initiator.

Base Sequence↗
PubMed1990

Pulmonary endodermal tumor resembling fetal lung: a clinicopathologic study of five cases with immunohistochemical and ultrastructural characterization.

Pulmonary endodermal tumor resembling fetal lung describes an uncommon neoplasm of the lung which also has been referred to as pulmonary blastoma and adenocarcinoma of fetal lung type. We describe five cases which fall within a narrow band on the spectrum of pulmonary neoplasms with both epithelial and mesenchymal features. These five cases all occurred as well-defined masses visible on chest radiograph in middle-aged females, and were treated by surgical excision. Histopathologically, low and high grades of malignancy are found. Well-formed racimose glands with cytoplasmic vacuolization resemble endometrioid carcinoma. Neoplastic columnar cells have abundant glycogen in the cytoplasm. Morules of cells within the glands have optically clear nuclei. Ultrastructurally, the optically clear nuclei are occupied by a filamentous substructure of chromatin. Multiple neuroendocrine hormones are present in low-grade malignancy. Nuclear pleomorphism, lymphatic invasion, multifocal necrosis, lack of mesenchyme at the pulmonary interface, and restricted neuroendocrine expression suggest high-grade malignancy. A mesenchymal stroma surrounding the glands is an intrinsic part of the neoplasm, but the stroma does not appear malignant, and did not form part of the metastasis in the single case where a metastasis occurred. Stromal cells show fibroblastic and myofibroblastic differentiation. Pulmonary endodermal tumor resembling fetal lung typically is a low-grade malignancy, with a better prognosis than the majority of lesions sometimes described as pulmonary blastoma or adenocarcinoma of fetal lung type.

Adult↗
PubMed1990

Characterization of human cDNA and genomic clones for glial fibrillary acidic protein.

Both a partial cDNA clone and a complete genomic clone have been isolated for human gfa, the gene encoding the major component of astrocyte intermediate filaments, glial fibrillary acidic protein (GFAP). The nucleotide sequence of the entire coding region and 102 bp of the 5' flanking DNA was determined. The mRNA start site was identified by primer extension and probe protection experiments, and a novel in vitro transcription and translation procedure was then used to establish that the first ATG in the mRNA initiates GFAP synthesis. The predicted amino-terminal sequence for human GFAP differs greatly from that previously deduced for mouse GFAP from its gene sequence, despite otherwise high homology. This discrepancy was resolved by determining that the published mouse genomic sequence has an incorrect additional base. The corrected sequence produces strong homology between human and mouse GFAP in their predicted amino acid sequences, and suggests that human and mouse GFAP initiate at homologous positions. The beginning sequence deduced here for both proteins is matched closely by that previously obtained for porcine GFAP by direct sequencing of its amino-terminal end. This supports the protein initiation sites proposed, and also indicates that GFAP is not processed at its amino-terminal end.

Base Sequence↗
PubMed1990

An RNA polymerase II promoter containing sequences upstream and downstream from the RNA startpoint that direct initiation of transcription from the same site.

The gfa gene encodes glial fibrillary acidic protein (GFAP), an intermediate-filament protein expressed primarily in glial cells. We have used in vitro transcription studies to show that the basal level of transcription of the human gene encoding GFAP is controlled by two distinct initiators--i.e., promoter elements that direct transcription from a specific start site. One initiator is located about 25 base pairs upstream from the transcription start site, contains a TATA box, and apparently acts together with a sequence found around the transcription start site. The other initiator is located between +11 and +50 bp downstream from the transcription start site. Most of this second region overlaps with the protein-encoding sequence, which starts at bp +17. The sensitivity of transcription to alpha-amanitin indicates that both initiators are used by RNA polymerase II.

Amino Acid Sequence↗