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In Liaoning Province in northeastern China, we found a G6PD-deficient patient at the age of 3. By the classification of the World Health Organization, this patient was categorized as class I (very severe G6PD deficiency). When we investigated the G6PD gene of the patient, we found that he had a replacement of G to A at nucleotide 1339. As a result, the amino acid at position 447 should change from Gly to Arg. This replacement is known as G6PD Santiago de Cuba, because it was first discovered in a Cuban boy who showed heavy chronic anemia. Today, 28 G6PD variants have been reported in the Chinese population, and all are categorized as class II (severe deficiency) or class III (mild deficiency);in class II or III deficiency, anemia is not present in daily life, but hemolytic attack can occur when the carrier ingests certain oxidative medicines or foods. This is the first report of a G6PD-deficient Chinese patient in the category of class I. We intended to find other G6PD-deficient cases in northeastern China and tested several hundred blood samples, but no cases of G6PD deficiency were found (0/414). In central China, where falciparum malaria was endemic from the 1950s to 1970s, we found two G6PD-deficient cases (2/27) and the other members from their families whose variant type was G6PD Kaiping (1388GT), which is a common variant in the Chinese population.

Effect of ornithine which is known to inhibit L-arginine uptake via cationic amino acid transport system has been tested, and compared to aminoguanidine, an iNOS inhibitor in lypopolysaccharide (LPS)-induced endotoxemia in rats. Serum nitrite/nitrate and malondialdehyde (MDA) level have been measured, and ileal histology has also been examined. Endotoxin increased serum nitrite/nitrate and MDA levels from 15.7+/- 2.4 micromol/ml and 2.1 +/-0.2 nmol/ml to 23.1 +/- 1.0 micromol/ml and 5.2+/- 0.3 nmol/ml (both P<0.05), respectively. In addition, LPS caused ileal degeneration. L-ornithine (500 mg/kg) did not improve septic manifestations, i.e., serum nitrite/nitrate and MDA levels did not differ from those in endotoxemia. Neither does it have an improving action on ileal histology. However, higher dose of L-ornithine (2,500 mg/kg) lowered the increased level of nitrite/nitrate and MDA by LPS. Moreover, it restored ileal histology from grade 3 (median) to 0 (median) (P<0.05). On the other hand, aminoguanidine (100 mg/kg) normalized serum nitrite/nitrate and MDA levels but not ileal histology in endotoxemic rats. In conclusion, high dose of L-ornithine could improve endotoxemic parameters in LPS-treated rats.

The rate of transport of blood glutamic acid into the brain and the rate of metabolic conversion of the amino acid in the brain were derived by the use of the brain perfution method in vivo and in situ with [D.HC] ·Lglutamic acid. The net uptake of glutamic acid by the brain was observed. Most of the radioactivity released from the brain into the cerebral venous blood was found to consist of glutamine. Small but significant amounts of output as radioactive GSH and CO2 were also found. Glutamic acid transport and its rate of metabolism were lowered in the glucose. free condition. The size of the compartment of the small glutamic acid pool, which was related closely to the blood glutamic acid, and that of the large glutamic acid pool, which was related closely to the blood glucose, were calculated and compared with each other.

The effect of pyridoxine treatment of a homocystinuric patient on the urinary excretion of some sulfur-containing amino acids was studied and the following results were obtained. As a result of pyridoxine treatment, urinary homocystine decreased to a fairly great extent, and its unusual metabolites S.(3-hydroxy-3-carboxyn- propylthio) homocysteine (HCPTHC) and S-C8-carboxyethylthio homocysteine (j3-CETHC) increased to some extent. But its oxidation product (homocysteic acid) showed a tendency to decrease slightly. Urinary methionine and cystine increased to some extent, but cysteinehomocysteine mixed disulfide showed no remarkable change.

The concentration and uptake of taurine in the umbilical and adult blood platelets were studied. Taurine was the most abundant free amino acid in both umbilical and adult blood platelets. The taurine concentration in umbilical blood platelets (2.30 pmoles/10(4) cells) was significantly lower than that of adult blood platelets (3.27 pmoles/10(4) cells) in contrast to the reverse relationship in taurine concentrations in umbilical and adult blood plasma. No other amino acid showed such significant difference in the concentrations between umbilical and adult blood platelets. Taurine uptake into umbilical blood platelets was temperature sensitive and sodium-dependent in a manner similar to that of adult blood platelets. The uptake conformed well to Hanes-plot. The Vmax of the uptake into adult blood platelets was about 3.6 times higher than that of umbilical blood platelets, but no significant difference was seen in the Km value between the two groups.

To test the hypothesis that the endothelium-derived relaxing factor (EDRF) contributes to coronary vasodilation induced by myocardial ischemia, we examined the effect of NG-nitro-L-arginine (a potent and selective inhibitor of EDRF release) on the coronary reactive hyperemic response in the open-chest dogs. Intracoronary infusion of NG-nitro-L-arginine at a coronary plasma concentration of 5 x 10(-5) M had no effect on hemodynamics and myocardial oxygen metabolism, but attenuated repayment of the flow debt by an average of 20.4% and 20.0% following coronary occlusion for 10 sec and 20 sec, respectively. Concomitant infusion of NG-nitro-L-arginine at the same concentration and 8-phenyltheophylline (a potent adenosine receptor blocker) at a coronary plasma concentration of 10(-5) M further attenuated flow debt repayment following 10 sec and 20 sec of coronary occlusion by 47.7 and 59.4%, respectively. These results indicate that EDRF plays a significant role in the coronary reactive hyperemic response and may cause vasodilation independently of adenosine-mediated vasodilation following coronary occlusion.

The contents of the sulfur amino acids, and the activities of cystathionine beta-synthase and cystathionine gamma-lyase were measured in various regions of the brain and several other tissues in both normal mice and rolling mice Nagoya. The cystathionine content and cystathionine beta-synthase activity were found to be unevenly distributed in various regions of the brain in both normal mice and rolling mice Nagoya, being highest in the cerebellum. Except for the mesencephalon and thalamus plus hypothalamus, the cystathionine content and cystathionine beta-synthase activity in the brain regions of rolling mice Nagoya were much higher than those of the normal mice. The cystathionine content after D,L-propargylglycine treatment was also found to be unevenly distributed in various brain regions in both normal mice and rolling mice Nagoya. The concentrations of cystine and methionine were also higher in all regions of the brain of rolling mice Nagoya than those of normal mice, while the concentration of taurine in the various regions of the brain was almost the same in normal mice and rolling mice Nagoya. Cystathionine beta-synthase and cystathionine gamma-lyase activities in the liver, kidney, and pancreas were almost the same in both the normal mice and rolling mice Nagoya.

Some bile acids (dehydrocholic, cholic, chenodeoxycholic, ursodeoxycholic, and deoxycholic acids), and some hypocholesterolemic agents (22, 25 diazacholestanol, 20,25-diazacholesterol, triparanol, and SKF 525-A) are the inducers of isovalthinuria in guinea pig. Administration of methionine appears to increase the pool of sulfur compound which participates in the formation of isovalthine. Cholesterol appears to have no enhancing effect on the induction activity of isovalthinuria inducers. The mechanism of isovalthine formation and the role of sulfur amino acids in lowering blood cholesterol are discussed.

The energy source required for the amino acid incorporation into mitochondrial proteins has been investigated and comparative study has also been made on the rate of the amino acid incorporation in rat liver and rat hepatoma cell mitochondria. 1. The incorporation of amino acid into the protein in intact mitochondria of rat liver increased by about 40% on the addition of α-ketoglutarate and ADP, but no significant increase in the amino acid incorporation was observed on the addition of succinate and ADP. 2. The incorporation of amino acids into mitochondrial proteins was remarkably inhibited by the addition of respiratory inhibitors (cyanide, DNP at a high concentration). 3. The amino acid incorporation into mitochondrial proteins was scarcely or slightly inhibited by the addition of DNP at the concentration of 1×10-4M and insensitive to oligomycin (5 to 10 μg/ml). 4. The amino acid incorporation into the protein in the endogenous substrate system of the mitochondria was considerably inhibited by the addition of arsenite, and this inhibition somewhat recovered on the addition of ADP plus succinate. 5. The rate of the amino acid incorporations between rat liver and hepatoma cell mitochondria was at the same level. 6. Discussions were made on the energy source required for the amino acid incorporation into mitochondrial proteins, on the rate of protein synthesis per mitochondrion isolated from rat liver- and hepatoma cells, and on the possibilities of contamination of bacteria or microsomes and of the adsorption of amino acids onto the mitochondria.

1. For the settlement of carbon origin of urinary isovalthine, acetic acid-2-C14, valine-U-C14 or leucine-U-C14 was administered to rats together with isovaleric acid as an isovalthinuria inducer, and urinary isovalthine excreted was tested by autoradiography. As the results of which, it was found that these isotopic compounds were not the precursor of urinary isovalthine. Although the isovalthinuria inducing effect of isovaleric acid was fairly diminished by these isotopic compounds, urinary isovalthine was detected by paper electrophoresis. 2. Some metabolic products of these isotopic compounds were also inquired in urine and some tissues. The results were as follows: a) Acetic acid incorporated into urea, aspartate, serine, glutamate, proline, glycine, alanine, ornithine, ethanolamine, r-amino-buthyric acid (brain only), cholesterol and fatty acids. b) Valine incorporated into urinary glutamate and glycine, and tissue cholesterol and fatty acids. Valine was rapidly excreted in urine and found in a very small amount in liver digest. c) Leucine incorporated into urinary aspartate, serine, glutamate and glycine, and tissue cholesterol and fatty acids. 3. Several important problems of isovalthine studies to be elucidated were discussed.

The compositions of nitrogen pools of ox liver, bladder bile, kidney and lung were analyzed with an especial bearing on their minor components, and some distinctive features of these tissues were described. DCEC and CMC were found in ox liver and kidney. Liver was low in free arginine and lysine, but high in ornithine, ethanolamine, and glutathione. Glycine was only a predominant amino acid in ox bile. All amino acids were contained moderately in kidney, but glutathione content was low. The concentrations of arginine and lysine were relatively high in lung.

Concentrations of ampholytes in the nitrogen pool of ox ocular tissues and nervous tissues were analyzed systematically by an automatic amino acid analyzer with a special reference to their minor components. DCEC was found in lens and also in nervous tissues. Ophthalmic acid was found in lens (highest), in retina (moderate), and in vitreous humor and spinal cord (trace). Glutathione content was extremely high in lens, and moderate in nervous tissues, retina and cornea. Carnosine content was moderate in cornea and in retina, but hemocarnosine may be rather high in nervous tissues. Anserine-like compound was found only in spinal cord, but free 1- and 3-methylhistidine were detected in most ocular tissues. Ethanolamine and γ-aminobutyric acid were high in retina and their concentrations were comparable to those of nervous tissues.

As a link in a series of studies on the effects of blood constituents on the brain function by means of brain perfusion, we used four kinds of artificial blood; namely, the blood containing a low molecular dextran, one containing glutamic acid, one containing essential amino acid group and the one containing both essential amino acid group and glutamic acid. During the perfusion experiments we observed the effects of blood constituents on the function and metabolism of the perfused brain and obtained the following results. 1. When a low molecular dextran is used as the colloid osmotic pressure agent instead of hydrodextran, the amount of the blood flow in the brain is maintained roughly at a certain fixed level throughout the experiment, showing no gradual decreasing tendency. 2. When using the artificial blood supplemented with glutamic acid, EEG of the perfused brain shows an increase in the appearance rate of β32 and β33 bands, approaching closely to the pattern of EEG of unrestrained controls at arousal state. 3. In the case of the blood added with essential amino acids similar to the case using the blood with glutamic acid, EEG approaches towards the alert pattern of the controls. 4. When the perfusion is done with the artificial blood lacking in amino acids, about one hour after the start of the perfusion the amount of glutamic acid and its related compounds in the brain can no longer be maintained at normal level and the decrease, being so marked, brings about a marked decrease also in total amino acid content. 5. When the perfusion blood contains glutamic acid, essential amino acid group or both, the concentrations of amino acids of the brain glutamic acid group and the total amino acid can be maintained approximately at normal level for the duration of over one hour.

FUKUTOME has once reported that isovaleric acid is an isovalthinuria inducer but isovaleric acid-1-C14 administered to a dog does not incorporate into urinary isovalthine and glutamic acid is most strongly labeled among acidic amino acids excreted. Recently, however, KUWAKI has found that liver homogenates of some animals can synthesize C14-labeled S-(isopropylcarboxymethyl) glutathione (GSIV) from isovaleric acid-1-C14 and glutathione, and that GSIV can be converted into isovalthine by kidney homogenate or glutathionase preparation4. For the elucidation of the above discrepancy, FUKUTOME's experiments were repeated by using isovaleric acid-methyl-C14 or-1-C14, and it was again found that these isotopic compounds did not significantly incorporate into urinary isovalthine.

In the course of studies on the cleavage reaction of S-(isopropylcarboxymethyl) glutathione (GSIV) into isovalthine in kidney homogenate or glutathionase preparation, it has sometimes been observed that the amount of isovalthine formed is far less than that of GSIV decomposed¹. Furthermore, when such reaction mixture is analyzed on an automatic amino acid analyzer, prominent peak corresponding to the reasonable amount of S-(isopropy1carboxymethyl)cysteinylglycine which is an expected intermediate of the GSIV cleavage reaction cannot be found up to 400 effluent ml. Though several reasons may be considered for the explanation of the above curious phenomenon, the effect of cystathionase on isovalthine is at first examined here. But the result was negative. L- and L-Alloisovalthineused as substrate were prepared by the method of OHMORI². Homoserine and purified cystathionase in ammonium sulfate solution prepared according to the method of GREENBERGB³ were kindly furnished by Prof. M. Suda of Osaka University. Incubation mixture contains 0.1 ml of enzyme solution, 1.0 ml of 0.2 M borate buffer (pH 8.0) containing 2×10-³M cysteine, 0.lml of 0.1 M substrate, and 0.8ml of deionized water containing 5×10-4M EDTA. The mixture was shaken at 37°C for 30 minutes in the air. The reaction was terminated by adding 2ml of 10% trichloroacetic acid and the α-keto acids formed were determined by the method of FRIEDEMANN and HAUGEN4 with a following modification: toluene extract was washed once with 8 ml of 10% sodium sulfate. The results obtained are summarized in Table l. When the reaction mixtures are analyzed before or after incubation on an automatic amino acid analyzer, the amount of L- or L-Alloisovalthine is found to be unchanged. Furthermore, as indicated in Table 1, L-isovalthine showed no inhibitory effect on the homoserine cleavage by cystathionase. Since amino acid oxidases have already been reported to have no effect on isovalthine³, the curious phenomenon above cited may have to be explained by other reaction mechanism such as transpeptipation reaction.

The blood levels of amino acids, ammonia and pancreatic hormones following the intragastric and intravenous administration of a branched-chain amino acid (BCAA)-enriched solution were comparatively investigated in control subjects and patients with liver cirrhosis. There was no essential difference in the time course of serum amino acid and blood ammonia levels between the intragastric and intravenous infusions. Elevation of serum insulin concentrations in cirrhotic patients was significant only immediately after the administration through the enteral route. However, plasma glucagon levels increased similarly when the BCAA-enriched solution was administered through either route. The results indicate that both enteral and intravenous infusions will have similar therapeutic effects on the impaired protein metabolism in cirrhotic patients with protein-calorie malnutrition.

Metabolism of 3-mercaptopyruvate was investigated using homogenates of rat heart, liver and kidney. When 3-mercaptopyruvate was incubated with heart homogenate, L-cysteine, L-alanine, S-(2-hydroxy-2-carboxyethylthio)-L-cysteine and 3-mercaptolactate were produced. At the same time, a decrease in the amounts of L-glutamate and L-aspartate was demonstrated. These results indicate that 3-mercaptopyruvate was converted to L-cysteine by cysteine aminotransferase (EC 2.6.1.3), to 3-mercaptolactate by lactate dehydrogenase (EC 1.1.1.27), and to pyruvate by 3-mercaptopyruvate sulfurtransferase (EC 2.8.1.2), and that HCETC and L-alanine were formed from these products. In the presence of liver homogenate, 3-mercaptopyruvate was mainly metabolized by 3-mercaptopyruvate sulfurtransferase; production of L-cysteine was small and HCETC was not formed. The metabolism of 3-mercaptopyruvate in the presence of kidney homogenate was intermediate between heart and liver: a fair amount of L-cysteine was formed, but HCETC was not produced. A peak which corresponds to L-cysteine-glutathione disulfide on the chromatogram of amino acid analysis was present when 3-mercaptopyruvate was incubated with heart or liver homogenate, but not with kidney homogenate.