[Progress on diagnosis and therapy of diabetic gangrene].
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Diabetic Foot↗
Biomedical subjects
A Ota
Publications and source records attributed to A Ota.
Regulation of N-terminus-deleted human tyrosine hydroxylase type 1 by end products of catecholamine biosynthetic pathway.
The N-terminal 52-, 70-, and 157-amino acids-deleted mutants and wild-type tyrosine hydroxylases were expressed in Escherichia coli and utilized to investigate the roles of the N-terminus in the catecholamine inhibition on enzyme activity. Their lysate's supernatants were used as enzyme samples. Three catecholamines, namely dopamine, norepinephrine, and epinephrine, affected both wild-type and mutant enzymes after preincubation in the mode of mixed inhibition, and the most marked alteration among the kinetic parameters produced by the deletion was the increase in the inhibition constants. The deletions also abolished the catecholamine-induced shift of the pH profile of the enzyme activity toward a more acidic pH optimum. All three mutants responded to catecholamines almost in the same way. These results suggest that the three catecholamine end products exert their inhibition on tyrosine hydroxylase to the same extent and that the N-terminal 52 amino acid residues contain the key sequence in mediating the inhibitory action.
Catalysis↗
Apoptosis in glomerular sclerosis.
Glomerulosclerosis is characterized by progressive extracellular matrix accumulation and glomerular cell loss. The role of glomerular cell apoptosis in glomerulosclerosis was investigated in the rat remnant kidney model and in human glomerular diseases. We identified apoptotic cells in the glomeruli, tubules and interstitium in the remnant kidney by electron microscopy. DNA fragmentation, which is a biochemical characteristic of apoptosis, was detected by in situ nick end-labeling of fragmented DNA with terminal deoxynucleotidyl transferase and biotinylated deoxyuridine triphosphate. Fragmented DNA in the glomeruli and tubules increased with the progression of glomerulosclerosis in the remnant kidney model. This finding was also demonstrated in other glomerular sclerotic lesions such as IgA and lupus nephritis. The number of cells positive for nick end-labeling in the glomerulus significantly correlated with the degree of glomerulosclerosis and the deterioration of renal function. These results indicate that apoptosis is, at least in part, involved in the cell deletion of various glomerular diseases leading to sclerosis.
Animals↗
Tetrahydrobiopterin biosynthesis enhanced by lipopolysaccharide stimulation in murine neuroblastoma cell line N1E-115.
We investigated for the first time the effect of lipopolysaccharide and the signal transduction pathway on the biosynthesis of tetrahydrobiopterin [(6R-L-erythro-1',2'-dihydroxypropyl) -2-amino-4-hydroxy-5,6,7,8-tetrahydropteridine], the cofactor for the enzymatic hydroxylation of the aromatic amino acids, in the murine neuroblastoma cell line N1E-115, which synthesizes tetrahydrobiopterin constitutively. Activation of N1E-115 cells with 1 microgram/ml lipopolysaccharide resulted in statistically significant increases in both intracellular tetrahydrobiopterin contents and the activity (Vmax) of GTP cyclohydrolase I, a rate-limiting enzyme in tetrahydrobiopterin de novo biosynthesis. Following simultaneous addition of the inhibitors of protein tyrosine kinases and GTP-binding proteins into serum-free culture media with lipopolysaccharide, we analyzed the transduction pathway of lipopolysaccharide signal toward the tetrahydrobiopterin biosynthetic system in N1E-115 cells. Our data indicate the following conclusions: (a) Protein tyrosine kinase systems are involved in mediating lipopoly-saccharide signal to tetrahydrobiopterin production, and (b) there may be a cross-talk between GTP-binding protein and the protein tyrosine kinase system in mediating lipopolysaccharide signal. These observations suggest that a neuronal cell such as N1E-115, which barely expresses CD14 on its cell surface, responds to lipopolysaccharide like macrophages and monocytes in the absence of soluble CD14.
Animals↗
Quantitative structure-activity relationships of Ca(2+)-antagonistic semotiadil congeners.
Structure-Ca2+ antagonistic activity relationships of semotiadil (1) congeners having a benzothiazine cyclic system were studied quantitatively by the Hansch-Fujita method. A quadratic dependency of the activity on ClogP, a lipophilic descriptor, of terminal arylalkylamine moieties was suggested. A correlation between the dipole moment component of the 5'-substituted 2-phenylbenzothiazine parts and the potency was also suggested. Additionally, quantitative analysis was successfully shown for the 2-substituted 1 congeners. The results gave information about the mode of binding of 1 with Ca2+ receptor.
Animals↗
Amounts of free amino acids during early sporulation in Saccharomyces cerevisiae.
The amount of free amino acids in cell-free extracts was examined during early sporulation of the yeast Saccharomyces cerevisiae. There was a slight decrease 2 h after transfer to the sporulation medium followed by a slight increase.
Amino Acids↗
[One-year outcome of panic disorder].
In this study we investigated the one-year outcome of panic disorder. The subjects were 169 panic disorder patients (69 males, 100 females; mean age 36.5 years), who attended the outpatient clinic of the Department of Psychiatry, Showa University Hospital, from September to December 1993. The outcome study was performed from October to December 1994. Patients who were being treated at Showa University Hospital during the outcome study were interviewed in person, and those who were not were interviewed by telephone. The one-year outcome of 100 patients (32 interviewed in person and 68 interviewed by telephone; 37 males, 63 females; mean age 39.5 years) was assessed. That of the remaining 69 patients was not assessed because they did not provide informed consent or had moved during the last year. The patients who were assessed (N = 100) were older and exhibited less severe phobic avoidance on their first visit to the clinic than those who were not assessed (N = 69). The frequency of panic attacks, and the severity of phobic avoidance and anticipatory anxiety decreased significantly between the time of the patients' first visit to the clinic and the time of the outcome study. Panic attacks, phobic avoidance and anticipatory anxiety disappeared in 27.0%, 32.9% and 13.6% and decreased in frequency or severity in 61.8%, 62.0% and 61.4% of the cases, respectively. Seventy-three patients felt that the severity of their panic disorder symptoms decreased between the time of the outcome study and the time of their first visit to the clinic, 20 felt that it had not changed and 7 felt that it had increased worse. The phobic avoidance and anticipatory anxiety at the time of the patients' first visit to the clinic were more severe, and the Global Assessment of Functioning Scale score was lower in the case of the former group of patients than in that of the latter two groups.
Adolescent↗
Deletion mutagenesis of human tyrosine hydroxylase type 1 regulatory domain.
A series of N-terminal deletion mutants of human tyrosine hydroxylase type 1 has been expressed in Escherichia coli to characterize the N-terminal regulatory domain. The mutants lacking the first 74 to 117 amino acids led to the precipitation into aggregates probably due to improper folding. All of the deletion mutants are active in the lysate supernatant and/or the pellet. The Michaelis constants of pterins are similar among all the mutants examined and the wild-type.
Amino Acid Sequence↗
Mouse sepiapterin reductase: an enzyme involved in the final step of tetrahydrobiopterin biosynthesis. Primary structure deduced from the cDNA sequence.
We carried out the cloning of a mouse cDNA encoding a sepiapterin reductase which is involved in the final step of tetrahydrobiopterin biosynthesis as a first step toward gene-targeting technique in mice. The sequence contained 1245 nucleotides consisting of an open reading frame of 783 nucleotides encoding a protein of 261 amino acid residues whose molecular weight was 27,851, a 5'-untranslated region of 21 nucleotides and a 3'-untranslated region of 441 nucleotides containing poly(A) tail. The amino acid sequence of mouse sepiapterin reductase revealed the identity of 88% with rat and 74% with human sequence.
Alcohol Oxidoreductases↗
[A case of cryoglobulinemia with decreased C4 and HCV antibody positivity].
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Complement C4↗
Alteration of catecholamine phenotype in transgenic mice influences expression of adrenergic receptor subtypes.
Agonist-induced regulation of adrenergic receptors (ARs) has an important role in controlling physiological functions in response to changes in catecholamine stimulation. We previously generated transgenic mice expressing phenylethanolamine N-methyltransferase (PNMT) under the control of a human dopamine beta-hydroxylase gene promoter to switch catecholamine specificity from the norepinephrine phenotype to the epinephrine phenotype. In the present study, we first examined changes in catecholamine metabolism in peripheral tissues innervated by sympathetic neurons of the transgenic mice. In the transgenic target tissues, a high-level expression of PNMT led to a dramatic increase in the epinephrine levels, whereas the norepinephrine levels were decreased to 48.6-87.9% of the nontransgenic control levels. Analysis of plasma catecholamines in adrenalectomized mice showed large amounts of epinephrine derived from sympathetic neurons in the transgenic mice. Subsequently, we performed radioligand binding assays with (-)-[125I]iodocyanopindolol to determine changes in binding sites of beta-AR subtypes. In transgenic mice, the number of beta 2-AR binding sites was 56.4-74.9% of their nontransgenic values in the lung, spleen, submaxillary gland, and kidney, whereas the beta 1-AR binding sites were regulated in a different fashion among these tissues. Moreover, northern blot analysis of total RNA from the lung tissues showed that down-regulation of beta 2 binding sites was accompanied by a significant decrease in steady-state levels of the receptor mRNA. These results strongly suggest that alteration of catecholamine specificity in the transgenic sympathetic neurons leads to regulated expression of the beta-AR subtypes in their target tissues.
Animals↗
Three antigenic regions in p17 of human immunodeficiency virus type 1 (HIV-1) revealed by mouse monoclonal antibodies and human antibodies in HIV-1 carrier sera.
We investigated the murine antibody response to recombinant p17 (rp17) of human immunodeficiency virus type 1 (HIV-1) and the human antibody response directed to p17 in HIV-1 infection. Three large peptides covering residues 12-29, 53-87 and 87-115 of p17 were synthesized. The cysteine residues 57 and 87 of peptide 53-87 were reoxidized to form a disulfide bridge. Eighteen out of 19 murine monoclonal anti-rp17 antibodies had relatively high affinities (KA = 1.9 x 10(5)-1.4 x 10(8) M-1) with one of the 3 p17 peptides in the liquid phase. Each monoclonal antibody reacted only with one particular peptide and had no reactivity with the other 2 p17 peptides. All the monoclonal antibodies reacted with rp17 in the liquid phase with a reasonable degree of affinity (KA = 2.0 x 10(5)-1.8 x 10(7) M-1). Four HIV-1 carrier sera, which were positive in ELISA using rp17 as the antigen, reacted positively in an ELISA using 3 p17 peptides which were used to titrate murine monoclonal antibodies. Murine monoclonal antibodies having specificity for the 3 p17 peptides stained live HIV-1-infected cells by means of indirect membrane immunofluorescence, irrespective of their specificity. This suggests that the various portions of p17 (at least 3 regions of p17) were exposed on the surface of live infected cells, probably as short polypeptide chains.
Amino Acid Sequence↗
A further prospective evaluation of an equation to predict daily lithium dose.
BACKGROUND: Recently, one prospective study confirmed the safety and accuracy of a lithium-dose prediction equation created by Zetin et al., but no definitive conclusion on the reliability of the equation has been established as yet. METHOD: The authors applied the Zetin et al. equation to 18 chronic male schizophrenic inpatients. Predicted doses to reach the serum lithium concentration of 0.4 mmol/L were calculated and prescribed in the form of lithium capsules. At Weeks 1 and 3 after treatment initiation, morning blood samples were collected about 12 hours after the last lithium dose for the measurement of serum lithium concentrations. RESULTS: None of the 18 patients achieved the desired concentration (0.4 mmol/L) exactly. The mean +/- SD of serum lithium concentrations at Week 1 was 1.01 +/- 0.29 mmol/L (range, 0.2-1.5) and at Week 3 was 0.94 +/- 0.35 mmol/L (range, 0.2-1.8). Lithium concentrations were lower than 0.4 mmol/L in only 1 patient and were higher than 0.4 mmol/L in the other 17 patients. The deviations from the unexpected value were significantly correlated with the renal function (blood urea nitrogen and serum creatinine levels) but not with the neuroleptic doses administered to the patients. Moreover, our patients were relatively older and weighed relatively less than the patients described in the previous prospective study. CONCLUSION: The Zetin et al. equation cannot always accurately predict a required lithium dose. Renal function data, even when they range within normal values, may be useful to improve the accuracy of the equation, particularly in patients who are older or weigh less than the norm.
Adult↗
Nicotine-induced regulation of tyrosine hydroxylase activity in adrenal gland of transgenic mouse carrying human tyrosine hydroxylase gene.
We investigated the effect of subcutaneous injection of nicotine on in vitro tyrosine hydroxylase (TH) activity in adrenal gland and brain of the transgenic mice carrying an 11-kb fragment containing the entire human TH gene. Injection of 5 mg nicotine/kg (as free base) for 3 days caused a statistically significant increase in vitro TH activity in the adrenal gland, whereas brain TH activity was not affected at all. The adrenal gland of non-transgenic C57BL/6J mice treated in the same way as for transgenic mice tended to enhance TH activity, although not to a significant level. This observation might indicate the possibility that the machinery used by nicotine in regulating the properties or expression of TH in the adrenal gland should be similar between transgenic and non-transgenic mice.
Adrenal Glands↗
Food-derived heterocyclic amines, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole and related amines, as inhibitors of monoamine metabolism.
The effects of heterocyclic amines, pyrolysis products of tryptophan, on monoamine metabolism were examined. Among these amines, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) are potent inhibitors of the enzymes related to amine metabolism. They inhibited type A monoamine oxidase more markedly than type B. After culture of a dopamine cell model, clonal pheochromocytoma PC12h cells, with Trp-P-1 activity of tyrosine hydroxylase was decreased by reduction of its affinity to the biopterin cofactor. Trp-P-1 and Trp-P-2 inhibited tryptophan hydroxylase competitively with the substrate and non-competitively with biopterin. These results suggest that food-derived heterocyclic amines may perturb the monoamine levels in the brain through the inhibition of the biosynthesis and metabolism of biogenic amines.
Amines↗
Distribution of beta 1- and beta 2-adrenoceptor subtypes in various mouse tissues.
The distribution of beta 1- and beta 2-adrenoceptor subtypes in mice was determined in crude membranes prepared from the submandibular gland, lung, spleen, heart and kidney, all of which are major target tissues of sympathoadrenal neurons. Scatchard analysis using [125I]-(-)iodocyanopindolol gave linear plots and the order of the density of total beta-adrenoceptors was lung > submandibular gland > spleen > kidney > heart. Competition binding studies using beta 1-selective antagonist CGP20712A indicated that all tissues examined possessed both high and low affinity sites which approximately stand for beta 1- and beta 2-adrenoceptor subtypes respectively despite the notable difference in the ratios of high and low affinity sites depending on the tissues. The order of the occupancy of high affinity sites was submandibular gland (71%), heart (55%), spleen (18%), kidney (17%), lung (14%). These results will be helpful to elucidate the regulatory mechanism which underlies beta-adrenergic functions in mice.
Adrenergic beta-Antagonists↗
The effect of a heterocyclic amine, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), on tyrosine hydroxylase mRNA in PC12h cells.
The effects of a naturally occurring heterocyclic amine, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indol (Trp-P-1), on tyrosine hydroxylase (TH) mRNA levels were examined in PC12h cells using Northern blot analysis. Dose-dependency of Trp-P-1 for 24 h incubation gave biphasic results; 0.1 microM Trp-P-1 enhanced and 10 microM Trp-P-1 reduced TH mRNA levels. These effects were faded out in 48 h. One hundred microM Trp-P-1 caused the almost complete abolishment of TH mRNA expression as well as cell death. These results suggest the possibility that lower dose of Trp-P-1 might function as a trophic factor in contrast to neurotoxic effect in higher doses.
Animals↗
Characteristics of the epitope of protein-reactive anti-peptide antibodies.
The specificity of hen egg-white lysozyme (HEL)-reactive rabbit antibodies induced by the peptide loop I.II (sequences 57-107 containing Cys64-Cys80 and Cys76-Cys94) of HEL was clarified by analyzing their cross-reactions with various avian lysozymes and their reaction with synthetic peptides (sequences 59-82) in which alanine was substituted for the amino acid at certain positions. The Arg-68 residue of HEL plays a dominant role in the binding, while Gly-71, Ser-72, Arg-73, and Pro-79 also contribute to the binding of two anti-Ploop I.II antibodies (rabbit number 125 and 126). These residues, although remote in sequence, are grouped together in the crystal structure of HEL and may form an area of contact with the antibody. Contributions by Trp-63, Ile-78, and Asn-77 to the binding of the two antibodies to HEL were excluded. These results support the idea that the anti-Ploop I.II antibodies recognize a conformational type of epitope which is similar to that of native HEL. The immunogenicity of the reduced and alkylated form of Ploop I.II was also tested, but it failed to induce an HEL-reactive antibody.
Alanine↗