[Socioeconomic analysis of nursing service--socioeconomic changes surrounding nursing].
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Biomedical subjects
Publications and source records attributed to Y Takagi.
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The effects of magnesium ions on a 32-mer ribozyme (R32) were examined by high-resolution NMR spectroscopy. In solution, R32 (without its substrate) consisted of a GAAA loop, stem II, a non-Watson Crick three-base-paired duplex and a four-base-paired duplex that included a wobble base pair. When an uncleavable substrate RNA (RdC11) was added to R32 without Mg2+ ions, a complex did not form between R32 and RdC11 because the substrate-recognition regions of R32 formed intramolecular base pairs (the recognition arms were closed). By contrast, in the presence of Mg2+ ions, the R32-RdC11 complex was formed. Moreover, titration of mixtures of R32 and RdC11 with Mg2+ ions also induced the ribozyme-substrate interaction. These data suggest that Mg2+ ions are not only important as the true catalysts in the function of ribozyme-type metalloenzymes but they also induce the structural change in the R32 hammerhead ribozyme that is necessary for establishment of the active form of the ribozyme-substrate complex.
Four oligodeoxynucleotides (15-mers), designated 13 through 16, and the corresponding conjugates, designated 17 through 20, in which psoralen was covalently linked to the 5' end of each oligonucleotide were synthesized. Compounds 16 and 20 contained a sequence that was complementary to part of the first four codons and the upstream sequence close to the ribosome-binding site of c-Ha-ras mRNA. Compounds 16 and 20 inhibited the growth of cells that had been transformed by the c-Ha-ras plasmid, with accompanying suppression of the expression of the activated c-Ha-ras oncogene. The antisense oligonucleotides 16 and 20 also appeared to cause partial reversion of the major phenotypic characteristics of transformed cells, which included inhibition of anchorage-independent growth. Compound 20, which contained psoralen, was a more efficient inhibitor of the growth of transformed cells than compound 16 without psoralen, a result that suggests psoralen might have increased the ability of the oligodeoxynucleotides to enter the cells.
Fetuin, an abundant protein in fetal bovine plasma, is the bovine homolog of human alpha 2HS glycoprotein (alpha 2HS). In spite of numerous studies, the biological functions of both proteins remain elusive. We now report the remarkable 45Ca-binding activity of fetuin in fetal bovine serum that has been blotted on a membrane after electrophoresis. The Ca-binding ability of the purified protein was analyzed by equilibrium dialysis, which revealed that bovine fetuin had multiple Ca-binding sites, one of which had a Kd of 0.95 x 10(-4) M. It was also shown that the Ca-binding activity of fetuin was greater than that of albumin in serum of the bovine fetus at the late gestational stage. Since fetal bovine serum contains not only a high concentration of fetuin but also a high concentration of Ca, it is possible that fetuin functions to maintain high levels of Ca in fetal serum via normalization of the concentration of Ca2+ ions.
The present study was conducted to clarify the effects of N-ethyl-N-hydroxyethylnitrosamine (EHEN) and uracil in combination on renal carcinogenesis in female F344 rats. Group 1 animals (n = 30) received a 3-week simultaneous administration of 0.05% EHEN and 3% uracil, and group 2 (n = 26) 0.05% EHEN with a lower 1.5% dose of uracil. Group 3 (n = 30) was treated with 0.05% EHEN alone and group 4 (n = 28) received only 3% uracil for 3 weeks. In all the above four groups, the rats were given basal diet and water without chemical addition for a 48-week period after the 3-week treatment period. Group 5 (n = 33) received no chemicals for the entire 52 weeks. At the end of week 52, renal adenocarcinomas were found in 53%, 31% and 13% of the rats in groups 1, 2, and 3, respectively. The present study thus demonstrated that simultaneous administration of uracil enhances the occurrence of EHEN-induced renal adenocarcinomas in rats.
The cDNA clones that encode a putative mitochondrion-localizing isoform of cysteine synthase (O-acetyl-L-serine(thiol)-lyase, O-acetyl-L-serine acetate-lyase (adding hydrogen sulfide), EC 4.2.99.8), which is denoted as cysteine synthase C, were isolated from spinach (Spinacia oleracea L.). The cDNA encodes a polypeptide of 368 amino acids containing a putative transit peptide of 30-40 amino acids at the N terminus. This leader peptide sequence exhibited several structural features common to other mitochondrion-targeting transit peptides. Homology was also detected between the putative transit peptide sequence of cysteine synthase C and other mitochondrion-targeting leader sequences. A deduced amino acid sequence of cysteine synthase C exhibited a homology of 61% with cytoplasmic isoform A and 63% with chloroplastic isoform B. A bacterial expression vector of the cDNA clone could genetically complement an Escherichia coli auxotroph lacking cysteine synthase loci and could produce the functionally active and immunoreactive cysteine synthase in E. coli. DNA blot hybridization analysis showed the presence of one or two copies of cysC gene in the genome of spinach. RNA blot hybridization analysis indicated that the expression level of cysC gene was lower than those of cysA and cysB and that the mode of cysC expression was constitutive in green and etiolated seedlings of spinach. The molecular evolutionary study of cysteine synthase proteins from plants and bacteria suggested that a common ancestor cysteine synthase gene has evolved into five cysteine synthase gene families, plant isoform A family, plant isoform B family, plant isoform C family, bacterial cysK family, and bacterial cysM family.
We have previously identified two fibroblast growth factor (FGF) receptors with higher affinity for acidic FGF rather than basic FGF in a rat parathyroid cell line (PT-r). Carbohydrate analyses of the receptors suggested the presence of three different types of FGF receptors, a 150-kDa glycoprotein receptor, a approximately 150-kDa heparan sulfate-proteoglycan receptor, and a 130-kDa glycoprotein receptor (Sakaguchi, K., Yanagishita, M., Takeuchi, Y., and Aurbach, G.D. (1991) J. Biol. Chem. 266, 7270-7278). Here, we have cloned two isoforms of the FGF receptors from PT-r cells; one with two immunoglobulin (Ig)-like domains (clone a), and the other with an additional Ig-like domain and an acidic box (clone b). They showed highest homology to the mouse and human keratinocyte growth factor receptors among the FGF receptors reported. Clones a and b had one and three possible glycosaminoglycan attachment sites, respectively. Heparitinase treatment of PT-r cells transfected with clone a suggested that the protein for the 130-kDa glycoprotein receptor was encoded by clone a, and that the same protein also served as a core protein for the approximately 150-kDa heparan sulfate-proteoglycan receptor. Heparan sulfate glycosaminoglycan attachment to the 150-kDa receptor encoded by clone b was not detectable by the same enzyme treatment. Site-directed mutagenesis (from Ser to Ala) studies of the consensus sequence for the attachment of glycosaminoglycans further supported the presence of covalently attached heparan sulfate glycosaminoglycan in the approximately 150-kDa heparan sulfate-proteoglycan receptor. These receptors overexpressed in PT-r cells changed ligand accessibility or apparently translocated after changing extracellular calcium concentrations in a manner similar to the native receptors in PT-r cells (Sakaguchi, K. (1992) J. Biol. Chem. 267, 24554-24562), whereas those expressed in CHO-K1 or NIH/3T3 cells did not. These findings strongly suggest that the two FGF receptor isoforms cloned here represent the acidic FGF receptors that we reported earlier. A subpopulation of the receptors carries heparan sulfate glycosaminoglycan covalently attached to the core protein, and the change in ligand accessibility in response to the shift in ambient calcium concentration is specific to the parathyroid cells.
Peroxidasin is a novel protein combining peroxidase and extracellular matrix motifs. Hemocytes differentiate early from head mesoderm, make peroxidasin and later phagocytose apoptotic cells. As hemocytes spread throughout the embryo, they synthesize extracellular matrix and peroxidasin, incorporating it into completed basement membranes. Cultured cells secrete peroxidasin; it occurs in larvae and adults. Each 1512 residue chain of the three-armed, disulfide-linked homotrimer combines a peroxidase domain with six leucine-rich regions, four Ig loops, a thrombospondin/procollagen homology and an amphipathic alpha-helix. The peroxidase domain is homologous with human myeloperoxidase and eosinophil peroxidase. This heme protein catalyzes H2O2-driven radioiodinations, oxidations and formation of dityrosine. We propose that peroxidasin functions uniquely in extracellular matrix consolidation, phagocytosis and defense.
Ischemia-induced changes in neurotransmitter release and their mechanisms were examined using cultured bovine adrenal chromaffin cells. When the cells were incubated in glucose-free media equilibrated with 0% O2/100% N2 (ischemia), ATP content decreased and reached the minimum level within 40 min. Control incubation was done in media equilibrated with 21% O2 in N2. After 10-min incubation under ischemic conditions, basal catecholamine (CA) release was elevated and the elevation persisted up to 90 min. High K(+)-evoked CA release was transiently enhanced at 10 min, but after that, it decreased to reach the minimum level at 60 min. At 10 min, cytosolic free Ca2+ concentration ([Ca2+]i) and 45Ca2+ uptake of the resting cells (basal values) and high K(+)-evoked increases in these two parameters were unchanged, but CA release from permeabilized cells in response to Ca2+ in media was augmented. After 60-min incubation under ischemic conditions, basal [Ca2+]i was elevated: the elevation was observed even in the absence of extracellular Ca2+. In contrast, high K(+)-evoked increases in [Ca2+]i and in 45Ca2+ uptake were suppressed, but basal 45Ca2+ uptake into intact cells and CA release from permeabilized cells were unchanged. These results suggest that in an early phase (10 min) of ischemia, both basal and stimulation-evoked CA release are augmented because of increased sensitivity of exocytotic machinery to Ca2+. In the late phase (60 min), basal CA release is augmented because of an increase in basal [Ca2+]i, which is due to accumulation of Ca2+ derived from intracellular Ca2+ pools: stimulation-evoked CA release is suppressed because of inhibition of stimulation-evoked increase in [Ca2+]i, which is due to functional disturbance of voltage-dependent Ca2+ channels.
Aromatase in the brain is supposed to participate in sexual differentiation of the brain. The presence of a brain-specific exon 1 and promoter in the human aromatase gene was examined in the 5' regions of aromatase cDNAs isolated from the amygdala and hypothalamus areas. The DNA sequences of all the isolated clones were different in the 5' regions encoded by exon 1 from those encoded by any alternative exons 1 of human aromatase gene. This unique sequence was also found in the clones isolated from a human genomic library and indicated to be that of a new exon 1. It involved putative TATA and CAAT boxes, Ad4 sequence, and the androgen responsive element in the promoter region. Reverse transcriptase-polymerase chain reaction analysis of mRNAs in various tissues revealed that expression of this unique species of aromatase mRNA is specific for the brain, in particular in the fetal brain. These show that the aromatase gene in the human brain is expressed by means of the brain-specific exon 1 and promoter, and may be responsible for sexual differentiation of the brain in the fetal period.
To determine whether increased oxidative stress in diabetes mellitus is due to an impaired free-radical scavenger function in endothelial cells, GSH-dependent H2O2 degradation in human umbilical vein endothelial cells was studied. The GSH-dependent, NaN3-uninhibitable H2O2-degradation in endothelial cells was reduced by 48% (p < 0.001) when the cells were exposed to 33 mmol/l D-glucose vs 5.5 mmol/l D-glucose. This impairment was dependent not only on the D-glucose concentration in the medium but also on D-glucose specific metabolism, since neither 27.5 mmol/l L-glucose nor 27.5 mmol/l D-raffinose had any effect on the peroxide degradation activity. Activation of the glutathione redox cycle by H2O2 in cells exposed to high glucose concentrations was attenuated as compared with 5.5 mmol/l D-glucose because of: 1) a 42% decrease (p < 0.001) in intracellular NADPH content, and 2) a 34% reduction (p < 0.01) in glutathione release into the media. This results in an accumulation of GSSG in the cells following exposure to H2O2. Both H2O2-evoked 51Cr-release and H2O2-induced endothelial cell damage were significantly (p < 0.01) greater in the 33 mmol/l D-glucose group than in the 5.5 mmol/l D-glucose group. These results indicate that the abnormal glutathione redox cycle observed in endothelial cells is induced by high glucose concentrations in the medium, resulting in an impairment of reduced GSH-dependent H2O2-degradation. These abnormalities may associate with the increased cellular damage following an exogenous exposure to H2O2.
Pre-transplant blood transfusions are given as a means of desensitization to reduce the required dose of cyclosporin A (CsA). In this study, the effect of pretransplant blood transfusion on host survival and T-cell function against alloantigen were investigated. Male Lewis rats (RT1(1)) were used as the recipients in all experiments, and male DA rats (RT1a) were used as the blood and small bowel donors, and as a source of allogeneic stimulator cells. Male BUF rats (RT1b) were used as donors of third party blood, and of allo-stimulator cells in a delayed-type hypersensitivity (DTH) response. In our experimental design, Lewis rats were divided into the following groups according to the type of administration: (1) a donor-specific blood transfusion (DST) 8 days preoperatively and a concurrent 5-day course of CsA at 10 mg/kg per day; (2) a nonspecific third party blood transfusion (NST) and CsA at 10 mg/kg per day from day 8 to day 4 preoperatively; (3) CsA alone from day 8 to day 4 preoperatively; (4) DST alone 8 days preoperatively; or (5) no treatment, being the control group. Postoperative treatment consisted of CsA at 2.5 mg/kg per day for 30 days. Rats conditioned with NST plus CsA, CsA alone, DST alone, and the untreated control rats survived for 7.2 +/- 1.2, 9.0 +/- 2.2, 6.8 +/- 0.4, and 7.4 +/- 1.6 days, respectively. In contrast, the five rats conditioned with DST plus CsA survived for 100 days or more.(ABSTRACT TRUNCATED AT 250 WORDS)
To clarify the clinicopathological characteristics of small renal cell carcinomas (RCCs) the authors reviewed data for 154 RCC patients treated between January 1980 and September 1992. Of 20 patients with tumours of 3 cm or less in diameter, 12 (60%) had no related symptoms: 6 (30%) were found during routine physical check-ups and 6 (30%) were incidentally detected during examinations for diseases other than RCC. The remaining 8 (40%) patients demonstrated indicative symptoms. Most small tumours showed expansive growth and nuclear atypia was minimal or moderate. In all 20 cases, the lesions of 3 cm or less were confined to the kidney (pT1 to pT2b) and no lymph node metastasis was found. Only one (5%) had a distant metastasis, and venous involvement was also microscopically observed in only one patient (5%). The 5-year survival rates were 95% for patients with tumours of 3 cm or smaller, 74% for those of 3.1 to 5 cm, and 68% for those of greater than 5 cm. These findings revealed small RCC to demonstrate biologically less malignant behaviour. Early detection of such small lesions by ultrasonography should therefore improve the overall survival of patients with RCC.
To clarify which patients might most require total cystectomy after intravesical bacillus Calmette-Guérin (BCG) therapy, we reviewed data for 111 individuals with superficial bladder cancer. Of the 111 patients, 73 received the BCG treatment for prophylaxis of intravesical recurrence after transurethral resection (group 1), 24 therapeutically for Ta or T1 tumours (group 2), and 14 for eradicating carcinomas in situ (CIS, group 3). Although the BCG therapy significantly reduced frequencies of recurrence in group 1, 27 patients (37%) did develop tumours again. Tumours disappeared in 18 of 24 patients (75%) in group 2, and in 11 of 14 (79%) in group 3. The rate of disease progression was 6% for all 111 patients: 3% (2/73) for group 1, 17% (4/24) for group 2, and 7% (1/14) for group 3. A total of 16 of the 111 patients (14%) underwent total cystectomy, the respective figures being 7% in group 1, 29% in group 2, and 29% in group 3. Indications for total cystectomy were progression in 7, recurrent multiple tumours in 5, persistent CIS in 2, a contracted bladder in 1, and occurrence of bilateral renal pelvic cancer in 1. Thus, 4 of 6 patients (67%) who had tumours unresponsive to BCG therapy in group 2 demonstrated progression and necessitated total cystectomy. Because tumours persisting after BCG therapy are frequently of the muscle-invasive type, such cases should be regarded as candidates for immediate total cystectomy.
The effect of amino acids on total parenteral nutrition (TPN)-associated cholestasis was examined using a newborn rabbit TPN model. Twenty-nine newborn Japanese white rabbits were divided into four groups. Group I received a TPN solution with composition and total energy similar to that of rabbit breast milk. Group II received more dextrose than group I. Group III received a larger amount of amino acids than group II. Group IV was nourished by lactating mothers. After 7 days of TPN, blood samples and liver specimens were obtained. In group II, the serum total bilirubin level (1.44 +/- 0.68 mg/dL) was significantly higher than normal (0.28 +/- 0.07 mg/dL) and that of group I (0.49 +/- 0.12 mg/dL). In group II, histological cholestasis was present, characterized by bile plugs in bile ducts, bile pigments in Kupffer cells and hepatocytes, and nonprotein calorie overload changes in clear cell transformation of the hepatocytes. In group III, the serum total bilirubin level (0.23 +/- 0.05 mg/dL) was normal, and there were minimal cholestatic and nonprotein calorie overload changes (histologically) in the liver. These results indicate that cholestasis in this study was induced by nonprotein calorie overload and was prevented by an appropriate volume of amino acids.
Activation of PI-PLC initiates two independent branches of protein phosphorylation cascades catalyzed by either PKC or Ca2+/calmodulin-dependent protein kinase (CaMK). We find that phosrestin I (PRI), a Drosophila homolog of vertebrate photoreceptor arrestin, undergoes light-induced phosphorylation on a subsecond time scale which is faster than that of any other protein in vivo. We determine that a CaMK activity is responsible for in vitro PRI phosphorylation at Ser366 in the C-terminal tryptic segment, MetLysSer(P)IleGluGlnHisArg, in which Ser(P) represents phosphoserine366. We also demonstrate that Ser366 is the phosphorylation site of PRI in vivo by identifying the molecular species resulting from in-gel tryptic digestion of purified phospho-PRI using HPLC-electrospray ionization tandem quadrupole mass spectroscopy. From these data, we conclude that the CaMK pathway, not the PKC pathway, is responsible for the earliest protein phosphorylation event following activation of PI-PLC in living Drosophila photoreceptors.