Katsumi Kato

Daily Walking Combined With Diet Therapy Is a Useful Means for Obese NIDDM Patients Not Only to Reduce Body Weight But Also to Improve Insulin Sensitivity

OBJECTIVE To evaluate the effects of walking combined with diet therapy (1,000–1,600 kcal/day) on insulin sensitivity in obese non-insulin-dependent diabetes mellitus (NIDDM) patients. RESEARCH DESIGN AND METHODS Subjects were divided into two groups: 10 patients were managed by diet alone (group D), and 14 patients were placed in the diet and exercise group (group DE). Group DE was instructed to walk at least 10,000 steps/day on a flat field as monitored by pedometer (19,200 ± 2,100 steps/day), and group D was told to maintain a normal daily routine (4,500 ± 290 steps/day). A glucose clamp procedure at an insulin infusion rate of 40 mU · m−2 · min−1 was performed before and after the 6-; to 8-week training program. Mean serum insulin concentrations ranged from 720 to 790 pmol/l. RESULTS While body weight (BW) in groups D and DE decreased significantly (P < 0.01) during the study, the amount of BW reduction in group DE was > that in group D (7.8 ± 0.8 vs. 4.2 ± 0.5 kg, P < 0.01). After training, glucose infusion rate (GIR) and metabolic clearance rate (MCR) in group D did not significantly increase; however, GIR and MCR increased significantly in group DE, from 17.21 ± 1.11 to 26.09 ± 1.11 μmol·kg−1 · min−1 (P < 0.001) and from 3.0 ± 0.3 to 5.3 ± 0.4 ml·kg−1 · min−1 (P < 0.001), respectively. The analysis of variance showed significant effects of exercise (time × exercise, P = 0.0005) for the improvement of MCR. Significant correlations were also observed between Δ MCR and average steps per day (r = 0.7257, P < 0.005) in group DE. CONCLUSIONS Walking, which can be safely performed and easily incorporated into daily life, can be recommended as an adjunct therapy to diet treatment in obese NIDDM patients, not only for BW reduction, but also for improvement of insulin sensitivity.

Quantitative analysis of extracellular-superoxide dismutase in serum and urine by ELISA with monoclonal antibody

The superoxide anion has been implicated in a wide range of diseases. The major protector against superoxide anion in the extracellular space is extracellular-superoxide dismutase (EC-SOD). EC-SOD is the major SOD isozyme in plasma and forms an equilibrium between the plasma phase and heparan sulfate proteoglycan on the surface of the endothelium. An ELISA method for the measurement of human EC-SOD with monoclonal antibody was established. The proposed method had a high sensitivity (assay range, 0.05-50 ng/ml), good recovery (recovery percentage, 96.9 +/- 5.6%) and reproducibility (within-day assay, C.V. = 8.6-10.2%; between-day assay, C.V. = 6.5-11.7%). EC-SOD levels in sera from healthy persons are clearly divided into two groups: a lower group (Group I, below 120 ng/ml, n = 146) and higher group (Group II, above 400 ng/ml, n = 10). The EC-SOD in Group I were almost normally distributed and the mean level was 55.8 +/- 18.8 ng/ml. The serum EC-SOD level assayed by ELISA correlated well with serum SOD activity. The serum EC-SOD in Group I is heterogeneous with regard to affinity for heparin-Sepharose and could be separated into three approximately equal fractions, whereas the EC-SOD in Group II is mainly one fraction with a high affinity for the column. The apparent molecular weight and carbohydrate structure of serum EC-SOD in Group II are identical to those in Group I. The high EC-SOD level in sera from some individuals may reflect the excessive stimulation of EC-SOD synthesis in vivo or the growth of selected cells in vivo, because EC-SOD is known to be expressed by a few cell types in vivo as a high-heparin-affinity subtype.

MOLECULAR ANALYSIS OF EXTRACELLULAR-SUPEROXIDE DISMUTASE GENE ASSOCIATED WITH HIGH LEVEL IN SERUM

SummaryExtracellular-superoxide dismutase (EC-SOD) is one of the SOD isozymes mainly distributed in the extracellular fluid. In the vascular system, it is located on the endothelial cell surface according to studies on the heparin binding capacity. By measurement of serum EC-SOD levels of Japanese in healthy persons (n=103) and hemodialysis patients (n=150), 7 healthy subjects and 24 hemodialysis patients were classified into group II associated with high EC-SOD levels. By molecular analysis of the EC-SOD coding region from the group II individuals in Sweden, a single nucleotide substitution of G to C generating an amino acid change of arginine to glycine has been identified in the region associated with the heparin affinity of the enzyme. The same mutation was detected in the Japanese as a homozygote in both alleles of 2 hemodialysis patients and as a heterozygote in one allele of all the healthy group II individuals and 17 hemodialysis patients. The amino acid substitution may result in the decrease of the heparin affinity which is favorable for the existence of EC-SOD in the serum.

Vagally mediated insulin secretion by stimulation of brain cholinergic neurons with neostigmine in bilateral adrenalectomized rats

This study investigated the relationship between central cholinergic neurons and insulin secretion in bilateral adrenalectomized fed rats. Neostigmine (a cholinesterase inhibitor, 5 x 10(-8) mol) administered into the third cerebral ventricle produced significant increases in hepatic venous plasma insulin and glucose concentrations, whereas i.v. injection of the same dose of neostigmine did not. Prior acute subdiaphragmatic vagotomy or i.p. pre-injection with methylatropine (10(-8) mol) completely prevented the neostigmine-induced rise in plasma insulin concentration. Intraperitoneal pretreatment with hexamethonium (5 x 10(-8) mol) also significantly reduced the plasma insulin response. These peripheral pretreatments did not change the plasma glucose response to neostigmine. Intraventricular co-administration of 10(-9) mol methylatropine, a dose that was ineffective when pre-injected i.p., eliminated the plasma insulin and glucose responses to neostigmine, whereas hexamethonium (5 x 10(-8) mol) had no influence on either response to neostigmine. These observations suggest that stimulation of central cholinergic-muscarinic neurons with third cerebral ventricular injection of neostigmine results in vagally mediated insulin secretion in bilateral adrenalectomized fed rats.

A lipoprotein lipase activator, NO-1886, improves endothelium-dependent relaxation of rat aorta associated with aging

Endothelial function is closely related to development of atherosclerosis and is impaired with aging. The novel compound NO-1886, 4-diethoxyphosphorylmethyl-N-(4-bromo-2-cyanophenyl)benzamid e, is a lipoprotein lipase activator and its long term administration protects against the development of experimental atherosclerosis in animals. The aim of this study was to ascertain whether NO-1886 ameliorates the impaired endothelium-dependent relaxation of rat aorta associated with aging. NO-1886 (50 mg/kg p.o.) was administered to 7-month old rats for 3 months. Plasma lipid, glucose and insulin levels in old control rats (10 months of age) were significantly higher than those of young rats (2 months of age). NO- 1886 decreased plasma triglyceride levels (old rats, 233+/-10 mg/dl; old rats + NO-1886, 172+/-16 mg/dl, P < 0.01) and increased plasma high density lipoprotein (HDL) cholesterol level (old rats, 72+/-6 mg/dl; old rats + NO-1886, 142+/-6 mg/dl, P < 0.001) in old rats, but had no effects on plasma glucose or insulin. The endothelium-dependent relaxation of the thoracic aorta caused by histamine was significantly impaired in old rats (% relaxation at 10(-5.5) M histamine: young rats 25.4+/-3.1%; old rats 14.1+/-1.9%, P < 0.01), an effect completely prevented by NO-1886 (old rats + NO-1886; 22.8+/-2.8%, P < 0.05 vs. old rats). In contrast, NO-1886 showed no effect on the endothelium-independent relaxation by sodium nitroprusside. These results indicate that NO-1886 improves impaired endothelium-dependent relaxation of rat aorta associated with aging, possibly by correcting lipid metabolism.

Ultrastructural identification and clinical significance of light microscopic giant mitochondria in alcoholic liver injuries

SummaryThe identification and clinical significance of light microscopic giant mitochondria (GM) were investigated in liver biopsy specimens of 60 alcoholics. By light microscopic examinations using the same section and neighboring sections, we suggest that light microscopic GM correspond to the crystalloid bodies (CB) detected on ultrastructural observation. The reasons are as follows: (1) difference in stainability between eosinophilic light microscopic GM and acidbasophilic mitochondria; (2) similarity in morphological features and density of the round- and cigar-shaped types at the light microscopic level to those of CB at the electron microscopic level; (3) similarity of the area occupied in the hepatic cytoplasm at both light and electron microscopic levels; (4) the crystalline structure of CB in compatible with the subtype of Mallory body (MB); (5) a description of CB has been made at the electron microscopic level, although not yet at the light microscopic level. Moreover, we clinically observed that light microscopic GM seldom appeared either in early fatty liver of cases aged 35 or less or the late macronodular liver cirrhosis stage of alcoholic liver injuries while they were frequently recognized during the acute aggravation phase of the chronic stage (GPT: p<0.05). Furthermore, if one was to assume that MB is a change accompanying necrosis of the liver cells, the light microscopic GM might be a change accompanying degeneration of the cytoplasmic organelles.

Influence of sympatho-adrenal system on insulin sensitivity using the euglycemic clamp technique

The aim of the present study was to further investigate the role of the adrenergic system on insulin action using the euglycemic clamp technique. Whole-body glucose metabolism (GM) was calculated as the glucose infusion rate for maintaining euglycemia under insulin infusion and used as an indicator of insulin sensitivity. Euglycemic clamps were performed in adrenodemedullated, epinephrine-treated, phentolamine-treated (alpha-blockade), propranolol-treated (beta-blockade), and epinephrine plus phentolamine and/or propranolol-treated rats. The following results were obtained at an insulin level of approximately 80 mU/l. GM in adrenodemedullated rats (13.97 +/- 0.98 mg/kg/min) was significantly higher than that of the control rats (10.26 +/- 0.50 mg/kg/min, P less than 0.01). GM in epinephrine-treated rats (1.7 mg/kg body weight/h) was 2.12 +/- 0.49 mg/kg/min (P less than 0.001 vs. control). Dose-response curves for phentolamine and propranolol established maximally effective doses (3.0 mg and 12 mg/kg body weight/h, respectively). Using these doses, GM in epinephrine plus phentolamine-treated rats (4.90 +/- 0.39 mg/kg/min) was significantly higher than that of epinephrine alone and GM in epinephrine and propranolol-treated rats (4.49 +/- 0.47 mg/kg/min) was also significantly higher than that of the epinephrine alone. GM in the epinephrine plus both propranolol and phentolamine (5.94 +/- 0.45 mg/kg/min) was significantly higher than that of the epinephrine alone, but not different from either treatment alone and was not additive. Neither phentolamine alone (9.48 +/- 1.45 mg/kg/min), propranolol alone (10.36 +/- 0.55 mg/kg/min) or the combination of blockades (11.14 +/- 0.65 mg/kg/min) had any effect on GM.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum activity and hepatic localization of Superoxide dismutase in alcoholics

SummaryA series of investigations was conducted to trace serum Superoxide dismutase (SOD) activities by ELISA and localizations of hepatic tissue SOD by the indirect method using peroxidase conjugated antibody, and the diagnostic and physiological significance of SOD in 19 alcoholics was studied. The values increased significantly both in serum Cu, Zn-SOD to 136±18 ng/ml(normally 33±9 ng/ml) and in serum Mn-SOD to 859±686 ng/ml(normally 84±30 ng/ml) respectively when polyclonal antibody was used (P<0.001). The increase in serum Mn-SOD was higher than that in serum Cu, Zn-SOD, fluctuations of these values showed similar tendencies. Meanwhile, serum Cu, Zn-SOD (94±50 ng/ml) identified by monoclonal antibody, also, showed higher values than that of normal subjects (37±7 ng/ml) (P<0.001). On the other hand, localization of hepatic tissue Cu, Zn-SOD in alcoholics varied, being 63.2% in the cytoplasmic diffuse type, 42.0% in the muclear diffuse type, 42.1% in the vacuolated membrane type, and 15.8% in the small granular type respectively. Participation of Cu, Zn-SOD in ethanol oxidation, protective roles played by cell membrane, lysosome membrane and nucleic acid of Cu, Zn-SOD to harmful free radicals was presumed. In addition, localization of hepatic tissue Mn-SOD was mostly of the cytoplasmic diffuse type (52.7%) and was extremely variable. From such results, relative or absolute reductions of hepatic tissue SOD in alcoholics was suggested to act on the development of tissue injuries acceleratingly.

Inhibition of Hydrolytic Activities of Human Dipeptidases Toward Leukotriene D4 and Kyotorphin by Capiopril

We investigated inhibition by captopril of the hydrolysis of leukotriene D4 (LTD4) and kyotorphin by human dipeptidases (DPases). The rate of LTD4 hydrolysis by kidney DPases F and S, pancreas and liver DPases were 60.6, 23.8, 23.3 and 0.358 units/mg protein, respectively. The inhibition by captopril was competitive for DPase F and liver DPase, and non-competitive for DPase S and pancreas enzyme. Using kyotorphin as a substrate, captopril inhibited four DPases competitively. From these results it is suggested that some side effects of captopril may relate to inhibition of hydrolytic activities of DPases with physiologically active dipeptides in man.