The influence of aging on the effectiveness of heat stress in preventing disuse muscle atrophy.

This study examined the aging effect on disuse muscle atrophy prevention using heat stress. Wistar rats aged 7 and 60 weeks were divided into three groups as follows: control, immobilized (Im), and immobilized and heat stressed (ImH). Heat stress was given by immersing the hindlimbs in hot water (42 °C) for 60 min, once in every 3 days and the gastrocnemius (GAS) and soleus (SOL) muscles were extracted after 14 days. Muscle-fiber types were classified using ATPase staining. Heat shock protein 70 (HSP70) was assessed through Western blotting. In GAS muscle of both groups and SOL muscle of 7-week-old rats, the fiber diameter of each muscle type in the ImH group significantly increased compared with that in the Im group. However, this could not be observed in the SOL muscle of the 60-week-old rats. The increased percentage of type-I fibers and variability of types I and II muscle-fiber diameter were evident in the SOL muscle of the 60-week rats. HSP70 was significantly elevated in the ImH group compared with in the Im group in both muscle types of both age groups. Thus, effectiveness of heat stress in the prevention of disuse muscle atrophy appears unsatisfactory in aging muscle fibers.

Influences of a dietary fatty acid composition on the emergence of glutathione S-transferase-P (GST-P) positive foci in the liver of carcinogen-treated rats.

The rats treated with a single i.p. injection of diethylnitrosoamine (DEN) and percial hepatectomy were fed for 11 weeks with a high fat diet mixed with 10% lard, eicosapentaenoic-acid-rich oil (EPA-oil) or arachidonic-acid-rich oil (AA-oil) and the emergence of glutathione S-transferase placental form (GST-P) in the liver was evaluated. There were no significant differences in the serum aminotransferase activities. The molar ratio of n-6 and n-3 fatty acid in the liver phospholipids was significantly low in the EPA-oil group compared with the other groups. In the EPA-oil group, the area percent and the unit area of GST-P positive foci were significantly smaller than the other groups. In the AA-oil group, no significant differences were recognized in the quantitative values for GST-P positive foci compared with the control and lard groups. In conclusion, a hepatic neoplasmic lesion induced by DEN was suppressed with EPA-rich fish oil, and arachidonic-acid-rich oil showed no effect of suppression or acceleration.

Effect of a moderately energy-restricted diet on obese patients with fatty liver.

The effects of a moderately energy-restricted (25 kcal/kg) diet on liver-function tests, anthropometric measurements, mononuclear-cell phospholipid fatty acid, lymphocyte blastogenesis, and plasma prostaglandin E2 and alpha-tocopherol levels were observed at weeks 0, 8, and 24 in 14 obese patients with fatty liver. Serum aminotransferase levels were improved significantly, with decreases in the body mass index and waist circumference. Decreases in energy intake from carbohydrate and increases in intake of vitamin A, vitamin C, and vegetables were observed at week 24. In mononuclear-cell phospholipids, linoleic acid (18:2omega 6), which was significantly lower in patients than in controls at week 0, was increased at week 24. In contrast, arachidonic acid was decreased. Plasma prostaglandin E2 levels were significantly lower in patients than in controls at week 0 and increased at week 24. The mononuclear-cell response for phytohemagglutinin correlated with 18:2omega 6 in mononuclear-cell phospholipids (r = 0.692, P < 0.01). Improvement of the serum alanine-aminotransferase level correlated with an increase in the plasma alpha-tocopherol level (r = -0.667, P < 0.01) and increases in consumption of vitamin A, omega 3 polyunsaturated fatty acids, and vegetables. These findings suggest that a hypoenergetic diet rich in omega 3 polyunsaturated fatty acids and antioxidants might be beneficial for obese patients with fatty liver.

[Influential factors in the elevation of serum creatine phosphokinase for the patients with Kanemi Yusho--freeze fracture study of rat muscle plasma membrane].

We studied the factors of the elevation of serum creatine phosphokinase (CK) using the data from the routine medical checkup of Kanemi Yusho patients during 1995 and 1999. We also studied rat muscle plasma membrane by the freeze fracture method, which were given the polychlorinated biphenyls (PCB) and controls. The patients with elevation of serum CK showed significant elevation of PCB in their blood but not in polychlorinated quanterphenyls (PCQ). The rat muscle plasma membrane showed a slight increase of orthognal array density but it was not statistically significant. The densities of caveolae and particles were not changed. Accordingly, PCB were thought to be a factor in the elevation of CK in the serum.

Effect of arachidonic acid-rich oil on lipids and arachidonate metabolites in ethanol- treated rats.

The effects of dietary arachidonic acid-rich oil (AAoil) on lipids and arachidonate metabolites in the liver and plasma were evaluated in ethanol-treated rats. Rats were fed a purified diet containing 10% weight of lard or AAoil for 14 days. Ethanol was administered by gavage at a single daily dose of 3 g/kg body weight. Comparing with the lard group, a decrease was observed in liver fatty vacuoles in the AAoil group. Plasma 6-keto-prostaglandin (PG) F1 alpha and thromboxane (TX) B(2)levels and the 6-keto-PGF1 alpha/TXB(2)ratio increased significantly in the AAoil group. Liver 6-keto-PGF1 alpha also increased but not leukotriene B(4)in the AAoil group. In the phospholipid fraction of liver tissue, plasma and red blood cells, arachidonic acid (20:4n-6) and docosatetraenoic acid (22:4n-6) increased and oleic acid (18:1n-9) and linoleic acid (18:2n-6) decreased significantly in the AAoil group compared with the lard group. These observations suggest that AAoil supplementation reduces liver injury of ethanol-treated rats, although longer observation will be necessary for confirmation.

The effect of dietary polyunsaturated fatty acid on insulin sensitivity and lipid metabolism in Otsuka Long-Evans Tokushima Fatty (OLETF) rats.

The effects of insulin sensitivity and lipid metabolism of dietary lard, eicosapentaenoic acid-rich oil (EPA oil) or arachidonic acid oil (AA oil) in Otsuka Long-Evans Tokushima Fatty (OLETF) rats were examined. Blood glucose was not different in each group at 30, 60, 120 min on an oral glucose tolerance test. Fasting blood glucose levels were lower in lard and AA oil groups than in controls. Hepatic triglyceride concentration and liver histochemistry revealed that the fat content was higher in the lard group and the AA oil group than in controls. The EPA oil group showed TG levels as high as the control group. Serum total cholesterol in the EPA oil group was lower, while the level in the AA oil group was higher than in the lard and control groups. HDL cholesterol was 1.5-fold higher in the AA oil group than in controls. Dietary EPA oil or AA oil supplementation showed different effects on lipid metabolism in this model.

Decreased food intake and body weight in pancreatic polypeptide-overexpressing mice.

BACKGROUND & AIMS: Pancreatic polypeptide (PP) is a 36-amino acid hormone produced by F cells within the pancreatic islets and the exocrine pancreas. The definitive function of PP in mammalian physiology remains to be determined. This study examined the effects of chronic overexpression of PP through the development of PP transgenic mice. METHODS: PP transgenic mice were created by using mouse PP complementary DNA under the control of the cytomegalovirus immediate early enhancer-chicken beta-actin hybrid promoter (pCAGGS expression vector). RESULTS: A unique line of transgenic mice was created that overexpresses PP in the pancreatic islets with low levels of expression in other tissues including the brain. Plasma PP concentrations were more than 20 times higher than those of control littermates. However, PP overproduction led to postnatal lethality in half of the pups because of markedly decreased milk intake. The remaining PP transgenic mice gained less weight with specifically reduced food intake and fat mass compared with controls, a result that was more evident in male than in female mice. The transgenic mice exhibited a reduced rate of gastric emptying of a solid meal but had normal oxygen consumption and fasting leptin levels. Immunoneutralization with anti-PP antiserum reversed the phenotypic changes of transgenic animals. CONCLUSIONS: PP could be involved in feeding and body weight regulation partly through regulation of gastric emptying.

[Influential factors in elevation of serum creatine phosphokinase for the patients with Kanemi Yusho].

We studied the etiology of the elevation of serum creatin phosphokinase (CK) using the data from routine medical checkup of Kanemi Yusho patients during 1995 and 1997. We also studied the serum CK and blood urea nitrogen (BUN) in rats given the polychlolinated biphenyls as well as controls, and conducted optical microscopic observation of muscle tissue in rats given the polychlolinated biphenyls and control. The patients with elevation of serum creatine phosphokinase also showed the elevation of BUN and polychlolinated biphenyls in their serum. These are thought to be triggers of the elevation of CK in the serum. However, animal experiments failed to yield the same results as human. The rats given polycholorinated biphenyls showed atrophy of muscle fibers. Accordingly, we were unable to clarify the etiology of CK elevation in humans and muscle atrophy in rats.

Low plasma levels of docosahexaenoic acid in patients with liver cirrhosis and its correction with a polyunsaturated fatty acid-enriched soft oil capsule.

Plasma levels of docosahexaenoic acid (DHA, C22:6 omega 3) were found to be decreased in 11 patients with alcoholic and non-alcoholic liver cirrhosis depending on the severity of liver damage. In this reduction, we found impaired metabolism of omega-3 long-chain polyunsaturated fatty acids in the cirrhotic liver and poor dietary intake of DHA to involved in the reduction of DHA plasma levels. The deficiency of this fatty acid, which is concentrated in the nervous tissues, may be related to the impaired neural function observed in hepatic encephalopathy of these patients. Oral DHA supplementation was supplied in the form of a polyunsaturated fatty acid-enriched soft oil capsule (omega 3/omega 6 ratio = 0.91, and P/S ratio = 1.87). Twelve capsules per day (containing 408 mg DHA, which corresponds to one-fourth of the DHA content in a normal daily diet) improved the DHA contents in the plasma phospholipid fractions of 5 alcoholic patients with low DHA levels.

Fatty acid composition and arachidonate metabolites in the livers of ethanol-treated rats fed an arachidonate-supplemented diet: effect of dietary fat.

The effects of 1% arachidonic acid ethyl ester (AA) administration on the liver prostanoid metabolites and on serum and liver lipids in 3 g/kg ethanol-administered rats fed 10% lard or corn oil were studied. The rats were divided into 6 groups: lard-sucrose (Lard-Suc); lard-ethanol without AA (Lard-Et); lard-ethanol with AA (Lard-EtAA); corn oil-sucrose (Corn-Suc); corn oil-ethanol without AA (Corn-Et); and corn oil-ethanol with AA (Corn-EtAA). Liver triglyceride increased in Corn-EtAA compared with Corn-Et. Arachidonic acid (20: 4n-6) levels in liver phospholipid were significantly decreased in Corn-Et, but elevated in Lard-Et. The levels of 20:4n-6 were significantly increased with AA administration in both ethanol groups. Liver 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) in Corn-Suc (24.7 +/- 5.1 pg/mg protein) was markedly higher than in Lard-Suc (4.5 +/- 1.2 pg/mg protein), and the 6-keto-PGF1 alpha lowered significantly with the addition of ethanol (9.3 +/- 0.9 pg/mg protein), but it increased with AA administration (21.6 +/- 4.9 pg/mg protein). In Lard-EtAA, a significant increase in 6-keto-PGF1 alpha was observed compared with Lard-Suc. The liver leukotriene B4 (LTB4) level in Lard-Suc was significantly lower than that of Corn-Suc. In the corn oil group, ethanol feeding was associated with a significant increase in liver LTB4. AA administration to Corn-Et suppressed the elevated LTB4. Serum thiobarbituric acid-reactive substance (TBARS) concentrations in the corn oil group were higher than in the lard group, and these concentrations were not altered by AA administration. From these results, we concluded that the administration of AA in rats treated with ethanol increased 20:4n-6 in liver phospholipid and liver PGI2 levels, irrespective of dietary fat, and may protect against alcoholic liver injury. AA with a diet rich in linoleic acid (18:2n-6), however, may increase fat in the alcoholic liver.

Effect of arachidonate on lipid metabolism in ethanol-treated rats fed with lard.

Two groups of rats, ethanol-treated and sucrose-administered control rats, were fed diets with different AA content (0, 2 and 3% weight) for 14 days. Ethanol was administered by gavage at a single daily dose of 3 g/kg body weight. The ethanol-treated rats showed significantly higher levels (p < 0.01) of serum ALT activity. The dietary AA supplement lowered the serum ALT activity and liver triglyceride both in control and ethanol-treated rats. Significantly lower levels of 20:4n - 6 and 20:4n - 6/18:2n - 6 ratio and higher levels of 18:1n - 9 in both the serum and liver triglyceride were observed in the ethanol-treated rats. The AA-supplemented diet induced a marked increase of 20:4n - 6 and subsequent significant decrease of 18:2n - 6 both in the liver and serum phospholipid in control and ethanol-treated rats. 18:1n - 9 in the serum and liver triglyceride in both groups was also markedly decreased by AA supplement. No significant difference was observed in the liver 6-keto-PGF(1 alpha) level between the ethanol-treated and control rats. In the ethanol-treated rats, the level of 6-keto-PGF(1 alpha) was elevated in the rats fed the 3% AA-supplemented diet. Though the liver leukotriene B4 levels were increased by ethanol administration in all rats, these levels were not increased by dietary AA.

[Elevation of serum creatine kinase in the patients with Kanemi Yusho].

18.9% of the patients with Kanemi Yusho showed an elevation of serum creatine kinase, however, the cause is still unknown. The relation between exercise, dehydration, thyroid hormone and concentration of PCB was studied. Dehydration, hyperexercise and PCB affected the elevation of creatine kinase. No relation between PCB and thyroid hormone or creatine kinase and thyroid hormone was observed. PCB may change the permeability of muscle plasma membrane.

n-3 and n-6 fatty acid intake and serum phospholipid fatty acid composition in middle-aged women living in rural and urban areas in Okayama Prefecture.

Dietary fatty acids and serum lipids were evaluated in 68 middle-aged women living in the northern, rural area of Okayama Prefecture, and were compared with the values obtained from 65 urban women from the southern part of this prefecture. A higher level in HDL cholesterol and a lower atherogenic index were observed in the rural women. The percent of energy intake as fat was lower (20.4 +/- 0.8% vs. 23.2 +/- 0.7%) and that of carbohydrate was greater in the rural group. Eicosapentaenoic (EPA, 0.41 +/- 0.04 g/day) and docosahexaenoic acid (DHA, 0.70 +/- 0.08 g/day) intakes were significantly higher in the rural subjects than in the urban group. Significantly higher DHA levels and n-3/n-6 fatty acid ratios in serum total phospholipids were found in rural women in their fifties and the sixties compared to urban women. Dietary linoleic acid (LA) amounts were positively correlated with LA (p < 0.05), and negatively with the EPA (p < 0.05) and DHA (p < 0.01) contents of serum total phospholipids. These results suggest that the traditional Japanese diet, containing little fat but enriched in complex carbohydrates and n-3 fatty acids of marine origin, may be related to the low atherogenic index in this rural area.

Effects of valine on 15N incorporation into serum and tissue protein and non-protein fractions following 15N-L-leucine administration to normal and liver-injured rats.

Effect of proportion of three branched-chain amino acids (leucine, valine, and isoleucine:BCAA) for nitrogen utilization was studied in vivo by an intragastric administration of 15N-L-leucine to control rats and liver-injured rats treated with carbon tetrachloride (CCl4-rats). Following the administration of isonitrogenous dose of three amino acid solutions [Standard (15N-L-leucine, L-valine, L-isoleucine, and L-alanine; 11, 8, 6, 18 mg/ml), Low-Val (11, 2, 6, 23 mg/ml), and High-Val (11, 32, 6, 0 mg/ml)], 15N enrichments in serum albumin, liver, skeletal muscle, and brain proteins and non-protein fractions, and urea nitrogen were compared by using 15N-analyzer. In CCl4-rats, the 15N enrichment in liver protein fraction was significantly lower in the High-Val group than in the Low-Val group. However, the difference of 15N enrichment in serum albumin between Low-Val and High-Val groups in CCl4-rats was unclear. The 15N enrichments in non-protein fractions of the brains in CCl4-rats were about twofold those in the skeletal muscles and the highest 15N enrichment was recognized in the Low-Val group. In the non-protein fraction of skeletal muscle in CCl4-rats, significantly low 15N enrichment was shown in the High-Val group compared with the Low-Val group. The 15N enrichment in urinary urea was significantly higher in the High-Val group than in the Low-Val group in CCl4-rats. In the Standard group of control rats, 15N enrichments in serum albumin and protein fraction of skeletal muscle were higher than in other groups. In non-protein fractions of control rats, the lowest 15N enrichment in liver and the highest 15N enrichment in skeletal muscle were recognized in the Standard group. These results suggest that a large amount of valine supplement among BCAA is less useful for leucine utilization in liver-injured rats than in normal rats.

Peptide YY receptors in the brain.

Radiolabelled ligand binding studies demonstrated that specific receptors for peptide YY are present in the porcine as well as the canine brains. Peptide YY was bound to brain tissue membranes via high-affinity (dissociation constant, 1.39 X 10(-10)M) and low-affinity (dissociation constant, 3.72 X 10(-8)M) components. The binding sites showed a high specificity for peptide YY and neuropeptide Y, but not for pancreatic polypeptide or structurally unrelated peptides. The specific activity of peptide YY binding was highest in the hippocampus, followed by the pituitary gland, the hypothalamus, and the amygdala of the porcine brain, this pattern being similarly observed in the canine brain. The results suggest that peptide YY and neuropeptide Y may regulate the function of these regions of the brain through interaction with a common receptor site.

Nutritional treatment of liver cirrhosis by branched-chain amino acid-enriched nutrient mixture.

The effects of branched-chain amino acid (BCAA)-enriched nutrient mixture (nutrient-mixture) on the nitrogen metabolism and nutritional state were clinically investigated in 10 patients with liver cirrhosis. Nutrient-mixture-supplemented diet was prepared by adding 150 g nutrient-mixture daily to low-protein diet, and comparisons were made with a regular diet (control diet). Each diet supplied 2,100 kcal energy and 80 g protein per day. Patients were given control diet for 2 weeks and thereafter treated successively with nutrient-mixture-supplemented and control diet each for 2 weeks. Nitrogen balance improvement and positive balance were observed during the feeding of nutrient-mixture-supplemented diet. The composition of nitrogen compounds in urine and the fecal nitrogen excretion did not alter during the test period. Plasma aromatic amino acid (AAA) concentrations decreased and BCAA/AAA molar ratios increased significantly during the 1st and 2nd week of nutrient-mixture-supplemented diet administration. Plasma methionine concentration also decreased in the 1st week. Plasma pre-albumin levels rose significantly during the 1st and 2nd week of nutrient-mixture-supplemented diet administration, and the number connection test improved significantly following the supplemented diet. These results suggest that the use of nutrient-mixture in the nutritional treatment of liver cirrhosis had no deleterious effects on nitrogen metabolism and is useful for the improvement of plasma amino acid imbalance and protein-energy malnutrition.

Effect of a branched chain amino acid-enriched nutritional product on the pathophysiology of the liver and nutritional state of patients with liver cirrhosis.

A new nutritional product (SF-1008C) containing a high proportion of branched chain amino acids (BCAA) and low proportion of aromatic amino acids (AAA) and methionine was tested to see its effect on the impaired protein metabolism and abnormal nutritional state frequently observed in patients with advanced liver cirrhosis. A sharp increase in plasma BCAA levels and fall of AAA and methionine levels were found following the administration of an SF-1008C-supplemented diet to healthy controls and cirrhotic patients, which the BCAA levels increased only slightly following an isocaloric control diet. Blood ammonia levels increased within the normal range transiently following the diets. The SF-1008C-supplemented diet was given for 2 weeks to cirrhotic patients with histories of hepatic encephalopathy, who were taking a low-protein diet because of hyperammonemia. Serum prealbumin levels, nitrogen balance, molar ratio of plasma BCAA/phenylalanine and tyrosine, the number connection test and electroencephalograms improved during the period of the experimental diet. The results, therefore, indicate that a BCAA-supplemented diet is well tolerated by patients with advanced cirrhosis and useful for treatment of impaired protein metabolism. Furthermore, this product is beneficial in preventing hepatic encephalopathy in cirrhotics.