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Biomedical subjects

S Namioka

Publications and source records attributed to S Namioka.

At least 55 records · Page 3Linked to original sources
PubMed1987

Methionine toxicosis in cats.

Cats given DL-methionine (1 g/kg of body weight/day) developed severe hemolytic anemia with marked increase of methemoglobin (MetHb) concentration and Heinz-body formation at treatment-day 6 to 10. Cats fed 0.5 g of methionine/kg for 52 days had a moderate Heinz-body hemolytic anemia with methemoglobinemia at treatment days 17 to 31, but thereafter recovered from the anemia despite continuation of methionine feeding, indicating an adaptation of the cats. In vitro, significant (P less than 0.01) increases of MetHb concentration and Heinz-body formation were observed when RBC were incubated with plasma from cats fed (1 g of methionine/kg) or with 10 mM 3-methylthiopropionate, a product of methionine catabolism. However, these increases were not observed when RBC were incubated with 10 mM methionine. Seemingly, excessive methionine intake leads to production of an intermediate of the methionine catabolism that may affect RBC directly as an intensive oxidizing agent, resulting in an excessive oxidation of hemoglobin to MetHb and Heinz-body formation.

Amino Acids↗
PubMed1986

B lymphocyte differentiation and suppressor activity by T lymphocytes derived from neonatal and sucking piglets.

The capacity of porcine neonatal T and B lymphocytes was studied employing a protein A haemolytic plaque assay. Only a few peripheral blood lymphocytes (PBL) from newborn piglets differentiated into immunoglobulin (Ig)-producing cells on stimulation by pokeweed mitogen (PWM). Newborn PBL also suppressed the differentiation of adult PBL into Ig-producing cells. This suppressive effect existed in T-cell enriched populations and appeared to be equally effective in the generation of IgG and IgM-producing cells. When newborn B lymphocytes were cocultured with T lymphocytes from adults in the PWM system, their differentiation into IgG and IgM-producing cells was enhanced. No such enhancement was seen in cocultures of newborn T and B lymphocytes. The generation of Ig-producing cells in PBL from suckling piglets increased with ageing, and reached about half the adult mean at six weeks old. On the other hand, the suppressor activity of T lymphocytes was observed throughout the suckling period, although it gradually decreased with ageing and was not consistently demonstrated by five weeks of age.

Animals↗
PubMed1985

Use of nonprotein nitrogen in pigs: effects of dietary urea on the intestinal microflora.

The fecal flora of 2 pigs given an optimal protein diet (digestive crude protein, 13.3%) with 2% urea, 2 pigs given a low protein diet (digestive crude protein, 5.7%) with 2% urea, and 2 pigs given a low protein diet only were bacteriologically investigated before feeding of each diet and on feeding days 21 and 38. The addition of urea to a low protein diet was significantly decreased Lactobacillus (P less than 0.001), Bacteroidaceae (P less than 0.01), Peptococcaceae (P less than 0.05), and Megasphaera (P less than 0.01) in the feces. In addition, there was a marked suppression of anaerobic curved rods (mainly Selenomonas) to undetectable amounts in the feces. A significant reduction (P less than 0.01) of Bifidobacterium and a marked suppression of Megasphaera to undetectable amounts were observed in the feces of pigs given low protein diets without urea. Microbial groups in the ileum and colon of pigs on feeding day 38 were also analyzed. Effects of dietary urea on the intestinal flora included: (i) anaerobic curved rods and spiral rods were restricted mainly to the colon, (ii) smaller numbers of yeasts were present in the intestine, and (iii) Bacteroidaceae, Peptococcaceae, and Eubacterium in the colon were not changed. Many anaerobic isolates, including curved rods and spiral rods, in the colon of pigs may have an important role in urea use.

Animals↗
PubMed1984

Serum concentration and properties of alpha-fetoprotein and serum level of albumin in sucking piglets.

Porcine alpha-fetoprotein (AFP) was purified from the sera of four-day-old piglets using an immunoadsorbent column. The molecular weight of the AFP was 80,000 when determined by gel filtration on Sephadex G-200 and 75,000 when determined by sodium dodecylsulphate polyacrylamide gel electrophoresis. The isoelectric point of the AFP was pH 4.85 at 0 degree C. The maximum concentration of serum AFP was reached on the fourth day after birth (mean value 1.1 mg ml-1), and it then decreased to 10 micrograms ml-1 when the piglets were 35 days old. The concentration of serum albumin increased rapidly between birth and seven days old, reaching 16 to 17 mg ml-1 at seven days old. Between birth and seven days old, the serum concentrations of AFP and albumin were approximately inversely proportional.

Animals↗
PubMed1983

Nutritive value of acetate in growing pigs.

Twelve crossbred barrows from four litters (average initial body weight of 21 kg) were used to examine the nutritive value of acetate in growing pigs. The treatments were the addition of acetate in the form of triacetin to the basal diet at 0, 5 and 10% of the metabolizable energy (ME) intake. Metabolism tests were conducted during wk 1 and 4 on acetate. The responses of weight gain and N retention to increasing levels of acetate were linear (P less than .001). Efficiency of acetate utilization for body weight gain was .90 g/g acetate, and the mean N-sparing effect of acetate was 32.9 mg N/g acetate. In the liver, heart and femoral muscle examined from d 36 to 47 on acetate, there was a linear increase in RNA content (P less than .05) and in protein content (P less than .01), as the level of acetate intake was increased. Digestible energy and N-corrected ME (MEn) of acetate found in the first week on acetate were not different from its heat of combustion. Those found in the fourth week on acetate, however, were larger (P less than .05) than the heat of combustion. It was considered that a nutritional adaptation to acetate utilization, or a synergistic action of acetate with other energy sources, occurred. The energetic efficiency of acetate utilization for growth was estimated to be 56 to 59%.

Acetates↗
PubMed1983

Acetate-glucose relationship in growing pigs.

Twelve crossbred barrows from four litters (average initial body weight of 21 kg) were used to examine the relationship between acetate and glucose metabolism in pigs. The treatments were the addition of acetate in the form of triacetin to the basal diet at 0, 5 and 10% of the metabolizable energy intake. In the immediate postprandial period, the administered acetate decreased the venous plasma glucose concentration linearly (P less than .05) and increased linearly the venous plasma concentrations of lactate (P less than .01) and ketone bodies (P less than .001). There was a linear increase in the glycogen content of the liver (P less than .001), heart (P less than .001) and femoral muscle (P less than .01), as the level of acetate intake was increased. In the remote postprandial period (12 h after the last meal), glucose, which was considered to have been derived from hepatic glycogen storage, became the dominant blood metabolite in place of the acetate administered with the diet. This led to the reduction in hepatic production of endogenous acetate, arterial acetate concentration and in acetate utilization in the hind limb. Hepatic urea production was also decreased. Thus, there was a reciprocal change in acetate and glucose metabolism.

Acetates↗
PubMed1980

Incorporation of nitrogen-15 from dietary [15N] diammonium citrate into amino acids of liver and muscle proteins in germfree and specific-pathogen-free neonatal pigs.

Incorporation of 15N from dietary [15N]diammonium citrate ([15N]DAC) into amino acids isolated from hydrolyzed tissue proteins was investigated in the presence or absence of intestinal flora in neonatal pigs. The 15N was incorporated into all of the essential and nonessential amino acids from liver and muscles in one of two germfree pigs and two specific-pathogen-free pigs which were killed on the 5th day after the administration of [15N]DAC. But, a higher 15N concentration than natural abundance of 15N was not detected in histidine, lysine, and threonine from these tissues in another germfree pig killed the next day. Nitrogen transfer from DAC into all amino acids, including these three essential amino acids, may be possible in the specific-pathogen-free pig and even in the germfree pig.

Amino Acids↗
PubMed1979

Relationship between the intestinal permeability to macromolecules and invasion of septicemia-inducing Escherichia coli in neonatal piglets.

The influence of age and diet on the invasion of septicemia-inducing Escherichia coli and the endocytotic activity of the small intestinal epithelium were examined in colostrum-deprived conventional and gnotobiotic piglets orally infected with E. coli 078. The piglets infected at birth and the animals fed glucose-amino acids solution and infected at 3 days after birth soon suffered from septicemia caused by the invasion of E. coli 378. The piglets fed artifical milk and infected at 3 days after birth, however, showed resistance to the invasion of E. coli in the absence of passively acquired serum gamma globulin. The endocytotic activity of the small intestinal epithelium was more intense in the former than in the latter piglets. Some of the ileal epithelial cells of the piglets infected at birth contained organisms, although these cells were morphologically intact and showed intense endocytosis. The present results suggest that the intestinal permeability to macromolecules, which depends on the endocytotic activity of the small intestinal epithelium, might predispose neonatal piglets to colisepticemia.

Animals↗
PubMed1979

Appearance of 15N-labeled intestinal microbial amino acids in the venous blood of the pig colon.

Two experiments were done to determine whether pigs possess the ability to absorb amino acids synthesized from urea nitrogen by indigenous microbes in the large intestine. Incorporation of [15N]urea into amino acid fractions of bacterial cells from the rectum and of the deproteinized incubated medium were examined in an experiment in vitro. The isotope was incorporated into 17 amino acids and the ammonia fraction of these samples. The absorption of the microbial amino acids from the colon was investigated by determination of the 15N concentration of the free amino acids in the venous blood of the colon after infusion of the 15N-labeled microorganisms into the cecum. The increase of 15N concentration was also observed in the plasma-free amino acids (threonine, isoleucine, phenylalanine, lysine, histidine, arginine, aspartic acid, serine, alanine, cystine) of the blood from the colic branch of the ileocolic vein. The results of these experiments indicated that pigs have the ability to utilize the microbial amino acids synthesized from urea nitrogen in the large intestine.

Amino Acids↗