[Magnesium metabolism disorders].
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Carbohydrate Metabolism↗
Biomedical subjects
H Morii
Publications and source records attributed to H Morii.
Solubilization of prostaglandin D2 binding protein from porcine temporal cortex.
Prostaglandin (PG) D2 binding activity was retained at the highest level in the P2 fraction prepared from porcine temporal cortex with the use of buffer containing mannitol and quinacrine. Then, the activity in this fraction was solubilized with maximal recovery by 10 mM CHAPS. The specific PGD2 binding time-dependently increased and was saturated at around 70 nM. Scatchard plots were fitted to a straight line with a Kd value of 20 nM and Bmax of 120 fmol/mg protein. The binding sites showed high specificity for PGD2. In addition, heat and trypsin treatments remarkably decreased the binding activity. These results suggest that the specific binding protein for PGD2 can be solubilized from these membranes.
Animals↗
Solution structure of human growth hormone-releasing factor fragment (1-29) by CD: characteristic conformational change on phospholipid membrane.
The conformations of synthetic human growth hormone-releasing factor fragment (1-29) in the presence and the absence of 1,2-dimyristoyl-sn-glycero-3-phosphorylglycerol liposome as well as in aqueous 2,2,2-trifluoroethanol solution were investigated by CD spectroscopy. The secondary structure of the peptide in each solution was analyzed by two methods. Both results show that the peptide has an unordered structure in the aqueous solution, whereas it folds into helical structure in the aqueous alcohol and in the phospholipid solution. In addition, although the peptide exists as almost complete helix in the 50 vol% aqueous alcohol (80-90% helicity), it does not reach full helicity even in the solution containing excess amount of phospholipid liposome (maximum 65-70% helicity). The conformational difference is explained by the characteristic amphipathy of the peptide, i.e., the necessity to twist the separated amphipathic helical parts in the interaction with the phospholipid membrane probably makes the helicity of the peptide decrease.
Amino Acid Sequence↗
Role of putrescine in interleukin 1 beta production in human histiocytic lymphoma cell line U937.
Treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and incubation with lipopolysaccharide (LPS) induces interleukin 1 beta (IL-1 beta) production in the histiocytic lymphoma cell line U937. Here we investigated the effect of treatment with both TPA and 1 alpha, 25-dihydroxyvitamin D3 (1,25(OH)2D3) on LPS-induced IL-1 beta production in U937 cells. To clarify the mechanism of IL-1 beta production, the possible role of polyamines in this process was examined. Combined treatment with TPA and 1,25(OH)2D3 for 72 h followed by incubation with LPS for 24 h caused synergistic induction of both IL-1 beta release and mRNA expression. On the other hand, TPA increased the numbers of vitamin D3 receptors, which may be one mechanism of this synergistic induction. Ornithine decarboxylase (ODC), a rate-limiting enzyme for polyamine biosynthesis, was also induced by these compounds biphasically: the first peak of ODC activity was observed at 4 h of the incubation with the two compounds and the second peak was at 4 h after the addition of LPS. To find whether these peaks were related to IL-1 beta production, DL-alpha-difluoromethylornithine (DFMO), a specific irreversible inhibitor of ODC, was added together with TPA and 1,25(OH)2D3. DFMO decreased the cellular levels of putrescine and spermidine and suppressed IL-1 beta release and IL-1 beta mRNA expression by 65%. Exogenous putrescine, but not spermidine, abrogated these kinds of inhibition. Similar results were obtained with DFMO and the polyamines during the differentiation of the cells up to the monocyte or macrophage stage. These results thus suggest that changes in either of these intracellular polyamines, especially putrescine, help to regulate the differentiation of U937 cells, resulting in partial control of the regulation of IL-1 beta production.
Calcitriol↗
Asymmetric inclusion by de novo designed proteins: fluorescence probe studies on amphiphilic alpha-helix bundles.
The inclusion feature and supersecondary structure of the de novo designed proteins which are constructed with several amphiphilic alpha-helices and flexible linkage parts were investigated with fluorescence probes. Five types of small proteins (or peptides) have been designed, which are composed of 2, 3, 4, 4, and 6 helices, respectively, and are linked with only linear junctions except for one of 4-helix proteins. All of these proteins have inclusion ability for hydrophobic fluorophores. Further, by the analysis of fluorescence polarization anisotropy, it was suggested that these proteins include guest molecules in compact helix bundles constructed with about 4 helices. Asymmetric inclusion of both monomer and stacked dimer of acridine orange derivatives was found by means of induced circular dichroism except for the 4-helix protein with cross-junction. The chirality of the included dimer proved to be in accordance with the chiral sense of alpha-helical coiled-coil. The 6-helix protein has especially high efficiency in inclusion for any fluorophores examined in this study and brings about a significant blue-shift of maximal emission for 8-anilino-1-naphthalenesulfonate.
Acridine Orange↗
Roles of hypoalbuminemia and lipoprotein lipase on hyperlipoproteinemia in continuous ambulatory peritoneal dialysis.
To assess the mechanism of serum lipoprotein abnormalities in continuous ambulatory peritoneal dialysis (CAPD), we measured serum lipids, apolipoproteins, and postheparin lipases in 46 patients with end-stage renal disease (ESRD) treated on CAPD, 26 patients on hemodialysis (HD), and 29 healthy subjects. HD patients had higher serum triglyceride levels than the healthy controls, showing type IV and type III phenotypes. They had significantly lower activities of hepatic triglyceride lipase (HTGL) in postheparin plasma compared with controls, and postheparin lipoprotein lipase (LPL) was also decreased by 15%, although the latter change was not statistically significant. CAPD patients had elevated levels in triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and apolipoprotein (apo) B, showing type IV, III, and II (IIb and IIa) phenotypes. The mean LPL and HTGL activities in CAPD patients were not different from those of HD patients. CAPD patients with hyperlipoproteinemia had significantly higher serum albumin levels than those with normolipidemia. There was a significant positive correlation between albumin and apo B levels in CAPD patients. In hyperlipidemic CAPD patients, there was no difference in serum albumin concentrations or HTGL activities among lipoprotein phenotypes, whereas LPL activities were significantly higher in the patients with type II than those with type IV hyperlipoproteinemia. These results suggest that there was some linkage between alterations in serum albumin and lipoproteins, and that LPL was related to phenotypic variation of hyperlipoproteinemia in CAPD.
Apolipoproteins↗
Effects of body suspension on soleus muscle fibres and spinal motoneurones in the rat.
1. After 14 days of body suspension, fibre type composition and fibre cross-sectional area in the soleus muscle of 17-week-old male Sprague-Dawley rats were investigated. Oxidative enzyme activity of soleus motoneurones in the spinal cord was also examined. 2. After suspension, soleus muscle weight decreased by 44.2%, the cross-sectional area of SO and FOG fibres decreased by 60.4% and 58.6%, respectively. 3. The percentage of fibre types was not changed by suspension. However, ATPase activity after alkaline preincubation was markedly inhibited in FOG fibres. 4. Oxidative enzyme activity of soleus motoneurones was not changed by suspension. 5. This study demonstrates that using mature animals body suspension induces atrophy of fast- and slow-twitch fibres accompanied with the selective inhibition in ATPase activity of fast-twitch fibres, and without changes in histochemical profiles of the corresponding motoneurones.
Animals↗
Increased insulin-insensitive glucose transport in polymorphonuclear leukocytes from non-insulin-dependent diabetic patients.
We studied the transport rate of a non-metabolizable hexose analogue, 3-O-methyl-D-glucose, in polymorphonuclear leukocytes (insulin-insensitive cells) from patients with untreated non-insulin-dependent diabetes mellitus. The mean glucose transport rate was significantly elevated in the diabetic patients compared with healthy controls (13.3 +/- 3.7 vs 10.4 +/- 2.5 fl/cell.sec, mean +/- SD, p less than 0.01). In the diabetic subjects, glucose transport rates were positively correlated with HbA1c levels (r = 0.563, p less than 0.01) but had no relations with ambient plasma glucose concentrations. Short-term incubation with 20 mM D-glucose had no effect on glucose transport in those cells. When glucose transport rates, HbA1c and fasting plasma glucose levels were simultaneously measured at weekly intervals over a four-week period in three diabetic subjects, the alterations in transport rates generally paralleled the changes observed in HbA1c levels rather than plasma glucose concentrations. It can be concluded that unlike insulin-sensitive cells such as adipocytes and muscle, glucose transport in human polymorphonuclear leukocytes, which are insulin insensitive cells, is increased in patients with non-insulin-dependent diabetes mellitus. Long-term, not short-term, derangement of glucose metabolism seems to be associated with increased glucose transport rate found in those patients.
Adult↗
The antihypertensive effect of calcitonin gene-related peptide in rats with norepinephrine- and angiotensin II-induced hypertension.
To investigate the role of calcitonin gene-related peptide (CGRP) in blood pressure regulation, we used rats with hypertension, induced by the chronic infusion of norepinephrine or angiotensin II, and examined changes in the systemic hemodynamics using the radioactive microspheres method. CGRP (0.05 micrograms/kg per min) administered simultaneously with norepinephrine (1.8 mg/kg per day) significantly reduced the systolic blood pressure of conscious rats compared with norepinephrine infusion alone. Similarly CGRP given with angiotensin II (0.9 mg/kg per day) significantly reduced the systolic blood pressure compared with angiotensin II alone. The antihypertensive effect of CGRP was sustained for 6 days. CGRP infusion decreased the total peripheral resistance but caused no change in cardiac output compared with rats given only pressor substances. Thus, a subdepressor dose of CGRP can modulate the vasopressor effects of norepinephrine and angiotensin II. CGRP may be involved in the regulation of blood pressure via an effect on peripheral vascular resistance.
Angiotensin II↗
Phosphatidyltransferase activity in Bacillus megaterium.
Phosphatidyl transfer between phosphatidylethanolamine, phosphatidylglycerol or phosphatidylserine as donors and primary hydroxyl acceptors including ethanolamine, glycerol, serine and Triton X-100 has been shown to be catalysed by membrane particles derived from Bacillus megaterium strains ATCC 13632 and ATCC 14581. The rate of cardiolipin synthesis from phosphatidylglycerol in the presence of ethanolamine was an order of magnitude greater than that of phosphatidylethanolamine formation. Cardiolipin synthesis from phosphatidylethanolamine in the presence of glycerol was also observed, and was 1.5-fold greater than the formation of phosphatidylglycerol. Similar heat lability, effects of pH and of Triton X-100 for phosphatidyl transfer and cardiolipin synthesis indicate that both reactions were catalysed by cardiolipin synthase.
Bacillus megaterium↗
Regulation of prostaglandin E2 receptor binding activity in porcine temporal cortex by protein phosphorylation.
Regulation of prostaglandin (PG) E2 receptors was investigated in a 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate-solubilized fraction from the synaptic membrane of porcine temporal cortex. The fraction was preincubated with exogenous protein kinases, and then the binding of PGE2 was measured. PGE2 binding was increased approximately twofold by pretreatment with the catalytic subunit of cyclic AMP-dependent protein kinase (A kinase) or calmodulin-dependent protein kinase II but not by that with protein kinase C. The increase was dependent on the ATP concentration, with ED50 values being close to the Km values of these protein kinases. Protein kinase inhibitors specific for A kinase and for calmodulin-dependent protein kinase II abolished the effect in a dose-dependent manner, with IC50 values being similar to those reported. Further study using the catalytic subunit of A kinase revealed that the maximal binding capacity apparently increased without affecting the affinity and the rate constants for association and dissociation. On the other hand, acid phosphatase treatment reduced the binding activity to the level of nonspecific binding. In addition, treatment by A kinase did not affect the binding of guanosine 5'-(3-thiotriphosphate) by the GTP-binding proteins and the activation of adenylate cyclase mediated by stimulatory guanine nucleotide-binding regulatory protein, and therefore the phosphorylation is believed to occur on the receptor protein. The results suggest that the PGE2 receptor can take active phosphorylated and inactive dephosphorylated forms, of which only the phosphorylated one can bind PGE2.
Acid Phosphatase↗
Unregulated expression of the erythropoietin receptor gene caused by insertion of spleen focus-forming virus long terminal repeat in a murine erythroleukemia cell line.
A murine erythroleukemia (MEL) cell line, F5-5, expressed 10,000 binding sites for erythropoietin (EPO) per cell, 10-fold more than was expressed by other murine erythroleukemia cell lines and normal erythroid progenitors. Northern (RNA) and Southern blot analyses revealed overexpression of mRNA for the EPO receptor (EPOR) and rearrangement of one of the EPOR gene alleles in F5-5 cells, respectively. Molecular cloning of F5-5-derived cDNA encoding EPOR revealed that the 5' noncoding region of the EPOR cDNA corresponds to the 3' long terminal repeat sequence of the polycythemic strain of Friend spleen focus-forming virus (F-SFFVP). The aberrant EPOR transcripts containing the 3' long terminal repeat sequence were mainly expressed in F5-5 cells. The same integration upstream of the EPOR gene was also observed in other subclones and the parent cell line. It is possible that overexpression of EPOR by viral promoter insertion will confer growth advantage to an F-SFFVP-infected erythroid progenitor cell, leading to positive clonal selection through further leukemogenic steps.
Amino Acid Sequence↗
Decreased albuminuria by pravastatin in hyperlipidemic diabetics.
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Aged↗
Effects of parathyroid hormone-related protein on systemic and regional hemodynamics in conscious rats. A comparison with human parathyroid hormone.
PTHrp was discovered as a humoral hypercalcemic factor of malignancy and has been shown to bind the same receptor as PTH in rat bone cells, canine renal membranes, and rabbit renal microvessels. We investigated the global effect of human PTH(hPTH) and PTHrp on systemic and regional hemodynamics in conscious rats. The hypotensive response to PTHrp was more potent than that to hPTH. Although hPTH (15 micrograms/kg/min, i.v.) caused a significant increase in cardiac output, whereas PTHrp (5 micrograms/kg/min, i.v.) caused no change in cardiac output despite a similar hypotensive effect to hPTH, the effects of PTHrp and hPTHrp on regional hemodynamics were quite similar, and both peptides had a prominent vasodilatory effect on the coronary and hepatic arteries. Therefore, PTHrp appears to have an important role in blood pressure and regional hemodynamics as does hPTH.
Animals↗
Uremic serum contains humoral factor(s) larger than fifty kilodaltons which suppresses endothelin production in cultured endothelial cells.
Direct effects of human uremic serum on the production of endothelin-1 in cultured porcine endothelial cells were examined in this study. Uremic serum decreased the level of monomeric endothelin-1 secreted into the culture medium by endothelial cells. This effect occurred at a transcriptional step because uremic serum decreased the endothelin-1 mRNA level in those cells. For the partial characterization of this inhibitory activity, uremic serum was fractionated with a centricut column. Uremic serum contains humoral factor(s) larger than 50 kD which suppress the endothelin-1 mRNA level in cultured endothelial cells.
Animals↗
Circulating bone Gla protein in end-stage renal disease determined by newly developed two-site immunoradiometric assay.
As a marker for bone formation, bone Gla protein (BGP) levels in the circulation have been measured in clinical research and management for metabolic bone diseases. We evaluated the clinical availability of a newly developed two-site immunoradiometric assay (IRMA) for human BGP and determined the serum BGP concentrations using this methodology in patients with abnormal calcium metabolism including those with end-stage renal disease undergoing maintenance dialysis. A cross-reactivity test revealed that this assay system specifically recognizes intact molecules (1-49) of BGP and excludes fragments of the molecules (1-19, 12-33, 23-33). Serum BGP levels in dialysis patients were positively correlated with those by conventional radioimmunoassay (RIA) (r = 0.918, p less than 0.00001, n = 37) as well as normal individuals (r = 0.935, p less than 0.0001, n = 16). However, the levels of BGP determined by IRMA were estimated to be significantly lower than those by RIA (23.6 +/- 9.8 vs. 29.6 +/- 9.1 ng/ml, p less than 0.00001). These results suggest that this IRMA system, with a rapid and easy procedure, excludes fragment forms of BGP in the circulation, which are found in uremic sera and probably attributed to increased bone resorption. Further studies are needed to ensure that serum intact BGP levels mainly reflect BGP production in osteoblasts, particularly in end-stage renal disease.
Female↗
Clinical trial of 26,26,26,27,27,27-hexafluoro-1,25-dihydroxyvitamin D3 in uremic patients on hemodialysis: preliminary report.
A clinical trial was done by the Group, Japan to evaluate the efficacy of 26,27-F6-1,25(OH)2D3 on the calcium and bone metabolism of 43 uremic patients on hemodialysis, 24 men and 19 women with a mean age of 50.9 +/- 2.1 years. The initial dose administered orally was 0.05 micrograms/day for 2 weeks. Then the dose was increased every 2 weeks by 0.05 micrograms each time until the dose of 0.3 micrograms/day was reached or until serum calcium increased. 26,27-F6(OH)2D3 increased serum calcium levels significantly at a mean dose of 0.08 +/- 0.03 micrograms/day and at 0.05 micrograms/day of dose comparison in hemodialyzed patients. It decreased the serum level of PTH significantly at a mean dose of 0.14 +/- 0.06 micrograms/day and at 0.3 micrograms/day by dose comparison. The serum level of bone Gla protein increased significantly at a mean dose of 0.18 +/- 0.07 micrograms/day and at 0.25 micrograms/day by dose comparison in the same patients. These results suggest that 26,27-F6-1,25(OH)2D3 has a higher potency in calcium mobilization than 1,25(OH)2D3 in uremic patients on hemodialysis.
Calcitriol↗
Parathyroid hormone secretion in diabetes mellitus.
To investigate the parathyroid function in diabetes mellitus, we performed an oral phosphate load in 6 diabetic patients and 6 nondiabetic subjects without renal failure (serum creatinine less than 1.5 mg/dl). Each subject received a total of 2.0 g of phosphate daily per os on 5 consecutive days. Blood and urine samples were obtained daily before and 2 h after the administration of phosphate in the morning. All subjects responded with a similar increase in the serum phosphorus concentration and fall in the ionized calcium concentration. Intact parathyroid hormone levels rose by 2.6-fold in the control subjects but by less than 1.5-fold in the diabetic subjects. It was concluded that hyporesponsiveness of the parathyroid hormone to phosphate administration was found in the diabetic patients without renal failure.
Aged↗