Inhibition of plasma cholesterol ester hydroperoxide and phosphatidylcholine hydroperoxide formation as measures of antioxidant status.
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Allantoin↗
Biomedical subjects
N Noguchi
Publications and source records attributed to N Noguchi.
Surgical simulation for reconstruction of mandibular bone defects using photocurable plastic skull models: report of three cases.
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Ameloblastoma↗
Effect of blood collection imitating toxicokinetic study on rat hematological parameters.
The effect of blood collection imitating a one-month toxicokinetic study on hematological parameters was studied in male rats (6 weeks of age at the beginning of the experiment). Three groups were established according to blood sampling points per day; Group I (3 points), Group II (5 points) and Group III (10 points). These repeated blood samplings were carried out on the first and last days of this study, and one-point blood sampling was also done every week during the experiment. In each sampling, 0.3 ml of blood was collected from the jugular vein. There were no changes in Group I, but in other groups, especially in Group III, red blood cell counts, hematocrit and hemoglobin concentration decreased during repeated blood sampling. On the other hand, white blood cell counts also decreased, but recovered within 24 hr. Platelet counts did not show any decrement. From the present result, less than 0.9 ml of blood per day is conceivable as the volume without causing changes in hematological parameters. The baseline of the sampling volume can become one reference for toxicokinetic and toxicological studies.
Animals↗
[Tuberous sclerosis associated with subependymal giant cell astrocytoma and renal angiomyolipoma: a case report].
We presented a case of tuberous sclerosis (TS) associated with subependymal giant cell astrocytoma (SEGC) and renal angiomyolipoma (RAML). A 19-year-old female, who had been diagnosed as TS since she was 3 months old, was admitted with complaints of headache, vomiting, and abdominal pain. At 10 years of age, a ventricular tumor was shown on CT, and at 16 years of age a ventricular peritoneal shunt was placed for obstructive hydrocephalus. On admission, an abdominal CT showed bilateral renal huge multicystic tumors with hemorrhage, which were diagnosed as RAMLs. CT and MRI showed an intraventricular tumor near the foramen of Monro, and this tumor was removed through a transcortical approach. The pathological diagnosis was SEGA. Large sized RAMLs were identified by CT. Although TS is often associated with additional tumors in the brain, heart, kidney, and other organs, the combination of SEGA and RAML is quite rare. If ventricular peritoneal shunt is placed in a TS patient, risk of shunt malfunction should be taken into account.
Adult↗
Cloning and nucleotide sequence of the mphB gene for macrolide 2'-phosphotransferase II in Escherichia coli.
Macrolide 2'-phosphotransferase II [MPH(2')II] inactivates macrolide antibiotics. The mphB gene for MPH(2')II was cloned from Escherichia coli and sequenced. Analysis of the nucleotide sequence indicated that mphB encoded a protein of 302 amino acids with a molecular mass of 34483 Da. The carboxy terminal region of the deduced protein contained a sequence that resembled a conserved functional domain in aminoglycoside phosphotransferases.
Amino Acid Sequence↗
Selective determination of chloride and bromide ions in serum by cyclic voltammetry.
Voltammetric determination of chloride and bromide ions in serum was made using a one-body type Ag electrode, whose surface was covered with a dialysis membrane for preventing interference from proteins. This determination was based on measurement of the charge of the reduction wave of silver halide formed on the Ag electrode surface in a halide ion solution during a cathodic potential sweep. In this method, depending on the potential sweep range, the charge of the reduction wave of AgI, AgI + AgBr, or AgI + AgBr + AgCl can be measured. Here, the method was used to determine the chloride and bromide ions in artificial serum. Linear concentration ranges were 1.0 x 10(-2)-2.4 x 10(-1) M for chloride ions and 5.0 x 10(-3)-1.8 x 10(-2) M for bromide ions. The correlation coefficient was 0.999 in each case. The relative standard deviation for chloride ion (1.0 x 10(-1) M) was 1.9% (n = 10), and that for bromide ion (1.5 x 10(-2) M) was 2.5% (n = 10). Bromide ions at a relatively high concentration as the component of serum had no effect on the determination of the chloride ion in the serum. This method is thus useful for the selective determination of chloride and bromide ions in serum.
Blood Substitutes↗
Inhibition of oxidation of low density lipoprotein by troglitazone.
The effect of a new oral hypoglycemic agent troglitazone, (+/-)-5-[4-(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl-methoxy)benz yl]-2,4-thiazolidinedione as an antioxidant against the free radical-mediated oxidation of low density lipoprotein (LDL) was studied. The oxidation of LDL gives cholesteryl ester hydroperoxide and phosphatidylcholine hydroperoxide as major primary products. Troglitazone incorporated exogenously into LDL inhibited the oxidations of LDL induced by either aqueous or lipophilic peroxyl radicals and suppressed the formation of lipid hydroperoxides efficiently. Ascorbic acid added into the aqueous phase spared both endogenous alpha-tocopherol and troglitazone in LDL. It was also found by absorption spectroscopic and electron spin resonance (ESR) studies that troglitazone reacted rapidly with a galvinoxyl radical to give a chromanoxyl radical which gives the same ESR spectrum as alpha-tocopherol. This ESR spectrum disappeared rapidly when ascorbic acid was added into the system. These results show that troglitazone acts as a potent antioxidant and protects LDL from oxidative modification.
Antioxidants↗
Design and synthesis of new mitochondrial cytotoxin N-thiadiazolylanilines that inhibit tumor cell growth.
New N-thiadiazolylanilines were designed and synthesized to develop mitochondrial cytotoxins superior to SF 6847. The mitochondrial cytotoxin N-thiadiazolylanilines, TX-108 and TX-109, inhibited EMT6/KU mammary sarcoma cell growth at a low micromolar concentration. Their inhibitory activities were parallel to their mitochondrial cytotoxicity, such as uncoupling oxidative phosphorylation and inhibiting ATP synthesis. This report also supports the notion that the inhibition of tumor cell growth of inhibitor of protein tyrosine kinase AG17, which is identical to SF 6847, may be due to its mitochondrial cytotoxicity.
Adenosine Triphosphate↗
Ammonia response to exercise in patients with congestive heart failure.
OBJECTIVE: To assess energy depletion in skeletal muscle in patients with congestive heart failure by measuring blood purine metabolites during exercise and, at the same time, determine the implications of the ammonia response to exercise in these patients. SETTING: Tottori University Hospital, Yonago, Japan. PATIENTS: 49 heart failure patients (New York Heart Association (NYHA) grades I-III) and 16 normal subjects. MAIN OUTCOME MEASURES: Blood lactate, ammonia, and hypoxanthine levels were measured during exercise with expired gas analysis. RESULTS: In normal exercising subjects as well as in each heart failure subgroup, the ammonia threshold was significantly higher than both the lactate threshold [control: 21.8 (SD 5.3) v 17.4 (3.3) ml/kg/min; NYHA class I: 18.9 (3.8) v 15.5 (2.6); class II: 14.8 (2.5) v 12.7 (2.4); class III: 13.5 (2.6) v 11.8 (2.5)] and the ventilatory threshold (P < 0.01). The difference between the ammonia and lactate thresholds was noted in all normal subjects and in all heart failure patients. The ammonia threshold, however, was significantly lower in heart failure patients than in normal subjects and it decreased with increasing NYHA class (P < 0.01). Maximum ammonia levels were lower in the heart failure group and decreased further with higher NYHA classifications [control: 198 (52) mg/dl; NYHA class I: 170 (74); class II: 134 (58); class III: 72 (15); P < 0.01]. There were significant correlations between maximum ammonia values and maximum lactate, oxygen consumption, and hypoxanthine levels (r = 0.74, 0.48, and 0.87, respectively; P < 0.001). CONCLUSIONS: The ammonia threshold may reflect the onset of ATP depletion in exercising skeletal muscles, as opposed to the onset of anaerobic respiration. It seems therefore that energy depletion in skeletal muscles during exercise occurs after attaining the anaerobic threshold. Both aerobic and anaerobic capacities of skeletal muscle are reduced in patients with congestive heart failure.
Adenosine Triphosphate↗
Inhibition of oxidation of low density lipoprotein by vitamin E and related compounds.
The oxidation of low density lipoprotein (LDL) was carried out aiming specifically at elucidating the anti-oxidant action of alpha-tocopherol. Lipophilic and hydrophilic azo compounds and copper induced the oxidation of LDL similarly to give cholesterol ester and phosphatidylcholine hydroperoxides as major products. The antioxidant potency of alpha-tocopherol in LDL was much poorer than in homogeneous solution. Doxyl stearic acids were used as spin probe and incorporated in LDL. The rate of reduction of doxyl nitroxide in LDL by ascorbate decreased with increasing distance from the LDL surface. From the competition between the spin probe and alpha-tocopherol in scavenging radical, it was found that the efficacy of radical scavenging by alpha-tocopherol became smaller as the radical went deeper into the interior of LDL. On the other hand, 2,2,5,7,8-pentamethyl-6-chromal spared the spin label regardless of the position of nitroxide. The antioxidant activity of chromanols against LDL oxidation increased with decreasing length of isoprenoid side chain at the 2-position. All these results were interpreted by location and low mobility of alpha-tocopherol in LDL. The tocopherol mediated propagation was observed notably at low rate of radical flux, but this was suppressed by reductant such as ascorbic acid and ubiquinol.
Amidines↗
Human REG family genes are tandemly ordered in a 95-kilobase region of chromosome 2p12.
Reg, first isolated from a rat regenerating islet cDNA library, is expressed in regenerating islet beta-cells. Recently, it has been revealed that Reg and Reg-related genes constitute a multigene family, the Reg family. In human, the four REG family genes, i.e., REG 1 alpha, REG 1 beta, REG-related sequence (RS) and HIP/PAP, have so far been isolated. In this study, we analyzed YAC clones containing the four genes and performed two-color FISH to determine the map order of the genes. The human REG family genes are tandemly ordered in the 95-kbp DNA region of chromosome 2p12 as follows: 2cen-HIP/PAP-RS-REG I alpha-REG I beta-ptel.
Acute-Phase Proteins↗
Requirement of calmodulin-dependent protein kinase II in cyclic ADP-ribose-mediated intracellular Ca2+ mobilization.
Cyclic ADP-ribose (cADPR) is generated in pancreatic islets by glucose stimulation, serving as a second messenger for Ca2+ mobilization from the endoplasmic reticulum for insulin secretion (Takasawa, S., Nata, K., Yonekura, H., and Okamoto, H. (1993) Science 259, 370-373). In the present study, we observed that the addition of calmodulin (CaM) to rat islet microsomes sensitized and activated the cADPR-mediated Ca2+ release. Inhibitors for CaM-dependent protein kinase II (CaM kinase II) completely abolished the glucose-induced insulin secretion as well as the cADPR-mediated and CaM-activated Ca2+ mobilization. Western blot analysis revealed that the microsomes contain the alpha isoform of CaM kinase II but do not contain CaM. When the active 30-kDa chymotryptic fragment of CaM kinase II was added to the microsomes, fully activated cADPR-mediated Ca2+ release was observed in the absence of CaM. These results along with available evidence strongly suggest that CaM kinase II is required to phosphorylate and activate the ryanodine-like receptor, a Ca2+ channel for cADPR as an endogenous activator, for the cADPR-mediated Ca2+ release.
Adenosine Diphosphate Ribose↗
Action of nitric oxide as an antioxidant against oxidation of soybean phosphatidylcholine liposomal membranes.
To elucidate the protective role of nitric oxide (NO) against lipid peroxidation, the effect of NO donor on the formation of lipid hydroperoxide and consumption of alpha-tocopherol in the oxidation of soybean phosphatidylcholine liposomal membranes was studied. The oxidation was induced by either aqueous or lipophilic peroxyl radicals generated by the hydrophilic or lipophilic azo compound, respectively. It was found that NO acted as a potent antioxidant by scavenging peroxyl radicals rapidly. It was also found that NO was capable of penetrating multilamellar membranes to scavenge lipid peroxyl radicals and spare alpha-tocopherol.
Antioxidants↗
Hepatic damage induced by perfusion of radical generating azo compound and its inhibition by vitamin E.
The damaging effect of perfusion of hydrophilic radical generating azo compound on the liver of normal and vitamin E-deficient rats and its inhibition by antioxidants were studied in order to increase understanding of the action of free radicals on biological tissues. The hepatic damage was evaluated from the release of cytosolic enzymes such as glutamic oxaloacetic transaminase and glutamic pyruvic transaminase, mitochondrial oxidation metabolism and morphological change. Two kinds of hydrophilic azo compounds were used, one which decomposes spontaneously at a uniform rate to generate free radicals and the other which does not. The former induced hepatic damage in a dose-dependent manner, while the latter did not exert any damage. Both endogenous vitamin E in the membranes and a water soluble vitamin E analogue added simultaneously with a radical initiator suppressed the hepatic damage. These results show that the hepatic damage induced by perfusion of radical generating azo compound is caused not by the azo compound itself but by free radicals.
Alanine Transaminase↗
The structure of the Aplysia kurodai gene encoding ADP-ribosyl cyclase, a second-messenger enzyme.
The complete nucleotide (nt) sequences of the cDNA and gene encoding the marine mollusk Aplysia kurodai (Ak) ADP-ribosyl cyclase (ADRC) which synthesizes cyclic ADP-ribose (cADP-ribose), a second messenger for Ca2+ mobilization from endoplasmic reticulum, were determined. Ak ADRC consists of 258 amino acids (aa) (29 kDa). It shares 86% aa sequence homology with that from A. californica, and 31-32% homology with the human, rat and mouse cluster of differentiation 38 (CD38) that has both ADRC and cADP-ribose hydrolase activities. The Ak ADRC-encoding gene (ADRC) spans approx. 7 kb and contains eight exons and seven introns. The transcription start point (tsp) determined by primer extension analysis and S1 mapping is 28 bp downstream from the TATA box. This gene is expressed specifically in the ovotestis, although the mammalian CD38-encoding gene is expressed in many kinds of tissues and cells. The 5'-flanking region contains several consensus sequences responsible for the germ-cell-specific expression of the mouse zona pellucida 3 (ZP3) and Drosophila melanogaster chorion genes. The existence of the consensus sequences located at nt -1649, -1161, -234 and -90 may account for the ovotestis-specific expression of the Ak ADRC gene.
ADP-ribosyl Cyclase↗
The tetracycline efflux protein encoded by the tet(K) gene from Staphylococcus aureus is a metal-tetracycline/H+ antiporter.
The tet(K) gene from Staphylococcus aureus was highly expressed in Escherichia coli by an alteration of its initiation codon from TTG to ATG and its ribosome-binding sequence from GAGG to GGAGG [Noguchi, N. et al. (1994) Biol. Pharm. Bull. 17, 352-355]. The inverted membrane vesicles prepared from the tet(K)-expressing cells showed respiration-dependent [3H]tetracycline transport comparable to the vesicles from the tet(B)-expressing cells. The affinity of Tet(K) vesicles to tetracycline was the same as that of Tet(B) vesicles, whereas the former Vmax value was about 60% of the latter one. Contrary to Tet(B) vesicles, Tet(K) vesicles showed no significant minocycline uptake, which was consistent with the low minocycline resistance of the Tet(K)-producing cells. The tetracycline transport mediated by Tet(K) vesicles was coupled with proton transport and the translocation of 60Co2+ ions as well as in Tet(B) vesicles. This observation indicates that the class K tetracycline resistance determinant from Gram-positive bacteria also encodes a metal-tetracycline/H+ antiporter that is functionally similar to that encoded by tet(B), although there is a considerable difference in the primary sequences and the putative topologies of these Tet proteins.
Antiporters↗
Nicorandil suppressed myocardial purine metabolism during exercise in patients with angina pectoris.
To elucidate the effect of Nicorandil on myocardial energy metabolism and myocardial sympathetic activity, we administered Nicorandil orally to eight patients with angina pectoris prior to exercise testing. Arterial and coronary sinus levels of lactate, ammonia, hypoxanthine (HX), adrenaline and noradrenaline were measured during exercise in order to determine the irrespective myocardial extraction ratios (MER). Compared to placebo, Nicorandil increased the time to development of significant ST depression (322 vs 390 s) while decreasing the maximum amplitude of ST depression (0.244 vs 0.216 mV). Heart rate, systolic blood pressure, and the rate pressure product during exercise were not significantly affected. The MER of lactate, measured during exercise, was significantly higher after Nicorandil than placebo (13.6 vs 27.9). Similarly, the MERs of ammonia and HX were significantly higher after Nicorandil (-46.0 vs 7.4% and -47.0 vs 9.9% respectively). Nicorandil, had no apparent effect on myocardial sympathetic activity as the MERs of adrenaline and noradrenaline were essentially unaffected. We conclude that Nicorandil decreased myocardial ischaemia and suppressed myocardial accelerated purine metabolism (a marker of cellular energy metabolism) during exercise in patients with angina pectoris. This effect appears not to be related to myocardial sympathetic activity.
Administration, Oral↗
Interaction among vitamin C, vitamin E, and beta-carotene.
The effects of vitamin C (ascorbic acid), vitamin E (alpha-tocopherol), and beta-carotene as antioxidants and their cooperative action against the oxidation of lipid in solution, membranes, and lipoproteins have been studied and reviewed. Ascorbic acid and alpha-tocopherol act as potent, and probably the most important, hydrophilic and lipophilic antioxidants, respectively. They function at their own site individually and furthermore act synergistically. beta-Carotene has lower reactivity toward radicals than does alpha-tocopherol and acts as a weak antioxidant in solution. It is more lipophilic than alpha-tocopherol and is assumed to be present at the interior of membranes or lipoproteins, which enables it to scavenge radicals within the lipophilic compartment more efficiently than does alpha-tocopherol. The cooperative interaction between vitamin C and vitamin E may be quite probable, that of vitamin C and beta-carotene is improbable, whereas that between vitamin E and beta-carotene may be possible.
Antioxidants↗