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Biomedical subjects

N Sakamoto

Publications and source records attributed to N Sakamoto.

At least 325 records · Page 18Linked to original sources
PubMed1989

[The pain response of the tooth caused by placement of a labial archwire].

The incidence of pain and discomfort response of tooth caused by placement of a labial archwire was studied. The pain response was assessed in four degrees of pain index (score 0: no discomfort, score 1: discomfort, score 2: mild pain, score 3: severe pain). Materials consisted of 84 males and females with the permanent dentition from 10 years to 41 years. Results were as follows: 1) Of the 84 cases, 95.24 percent of them suffered from pain (mild pain: 26.19%, severe pain: 69.05%). 2) There was no significant difference in the pain response among the under 12 year old group, the 13 to 19 year old group and the over 20 year old group. 3) There was no significant difference in the pain response among the three kind of labial arch wire (0.014", 0.012" nickel titanium alloy wire and 0.015" braided wire). 4) The pain response was statistically higher in the female than in the male. 5) The pain response was observed in 8.75 percent of cases immediately after placement of archwire, and 31.25 percent 2 hours later, 41.25 percent by the end of the day. In 18.75 percent the pain response was observed next day. 6) Cases were sorted into 4 groups according to their highest score. In the severe pain group, the mean value of the severe pain response was 3.57 days, that of the mild pain response was 5.74 days and that of the discomfort response was 6.26 days. In the mild pain group, the mean value of the mild pain response was 3.68 days, and that of the discomfort response was 4.46 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Pancreatic alpha- and beta-cell function and metabolic changes during oral L-alanine and glucose administration: comparative studies between normal, diabetic and cirrhotic subjects.

The present study investigated whether or not, in addition to the oral glucose tolerance test, oral alanine loading was a useful diagnostic tool for hormonal and metabolic diseases. Fifty g of L-alanine was administered orally in 14 normal, 12 diabetic, and 8 liver cirrhotic subjects. The influence of oral alanine loading on hormones and metabolites was compared with the results of 100 g oral glucose loading. The results obtained were as follows: 1) In the normal subjects and cirrhotics, lactate and pyruvate concentrations gradually increased with time and reached their peak levels at 60 min, whereas they remained unchanged throughout the course in the diabetic group at glucose loading. 2) Alanine administration accelerated ureogenesis but did not affect blood glucose levels. 3) In both glucose and L-alanine administration, free fatty acid, glycerol and ketone body levels declined nonspecifically in all groups. 4) Serum glucagon levels during L-alanine loading increased in all groups, especially in liver cirrhotics. 5) L-alanine was a potent stimulus for insulin secretion in diabetics, while no insulin release during glucose loading was observed. 6) The molar ratio of insulin levels (during glucose loading)/glucagon levels (during L-alanine loading) was a good indicator of systemic glucose homeostasis from the hormonal aspect. It is suggested that, in addition to the oral glucose tolerance test, the oral administration of L-alanine can be a useful tool for the diagnosis of the status in diabetes mellitus and cirrhosis.

Administration, Oral↗
PubMed1989

Pre-S proteins in chronic hepatitis B virus infection: markers of active viral infection.

The role of large (pre-S1) and middle (pre-S2) proteins of HBsAg in hepatitis B virus (HBV) infection is not fully known. Therefore, we studied the expression of pre-S proteins in the liver and serum of 26 patients with chronic HBV infection, using immunoperoxidase staining and enzyme immunoassay. Pre-S1 and pre-S2 proteins were detected in a large number of patients in both liver and serum, irrespective of the disease activity. Serial sections showed that most cells positive for HBsAg were also positive for pre-S proteins. The localization of pre-S2 and HBsAg was similar, with cytoplasmic and membranous stainings of hepatocytes, whereas pre-S1 was expressed exclusively in cytoplasm. Serum levels of HBsAg, pre-S1, and pre-S2 of DNA polymerase-positive cases were significantly higher than those of DNA polymerase-negative cases. Membranous display of pre-S2 on hepatocytes was observed more often in DNA polymerase-positive patients, and their serum pre-S2 levels were significantly higher than those without it. The predominant localization of cytoplasmic HBcAg usually was associated with active, ongoing hepatitis. Its expression and DNA polymerase activity were significantly correlated. These results indicate that pre-S proteins in serum and the membranous display of pre-S2 on hepatocytes of patients with chronic HBV infection refect active viral replication, but their expression does not correlate with disease activity.

Hepatitis B↗
PubMed1989

[Preliminary study of patients with vertigo and dizziness using 123I-IMP].

To study the application of cerebral blood flow scintigraphy with 123I-IMP for the evaluation of central dizziness, the difference in 123I-IMP accumulation between the right and left cerebellar hemispheres was determined as an asymmetry index (A.I.) in 8 normal subjects and compared with A.I. from patients with central dizziness. According to estimated lesions, 123I-IMP findings were compared with CT findings. The normal subjects had A.I. of 5.8 +/- 2.1%, whereas 36 patients with central dizziness had A.I. of 12.7 +/- 7.5%. On the basis of an A.I. of 8% or more as an abnormal finding on IMP scintigraphy, 11 of the 14 patients with estimated lesions of cerebellar hemispheres and 16 of the 20 with those of the whole cerebellum including the vermis were evaluated to have had abnormalities. Seven of 11 with estimated lesions of the brainstem and 4 of 5 with vertebrobasilar arterial insufficiency were evaluated to have had abnormalities. The findings of 123I-IMP cerebral blood flow scintigraphy were in good agreement with clinical symptoms in patients with central dizziness with estimated lesions of the cerebellar hemispheres, suggesting the possibility that this method is more useful than CT.

Adult↗
PubMed1988

The sulfated polysaccharide-peptidoglycan complex potently inhibits embryonic angiogenesis and tumor growth in the presence of cortisone acetate.

In combination with cortisone acteate, the sulfated polysaccharide (SP)-peptidoglycan (PG) complex produced by an Arthrobacter species was found to inhibit both embryonic angiogenesis of chick chorioallantoic membrane (CAM) and growth of solid Sarcoma 180 tumor in mice. Three fractions obtained from the SP-PG complex by gel filtration showed a great difference in the inhibitory effect on angiogenesis of the CAM, whereas in ex vivo study such a difference was reduced. Of the three fractions, SP-PG-L having the lowest molecular weight and peptidoglycan content exhibited the highest antiangiogenic and antitumor activities, even higher than those of heparin. Neither desulfation nor sulfation of the SP-PG complex greatly affected the antiangiogenic activity, and dextran sulfates and mannoglucan sulfates were lacking the activity. This suggested that glycosyl sequences of sulfated polysaccharides are more important for the activity, rather than content or intramolecular distribution of sulfate groups.

Allantois↗
PubMed1988

cDNA cloning and sequence analysis of a chicken gene expressed during the gonadal development and homologous to mammalian cytochrome P-450c17.

A cDNA clone, pLOA0511, was isolated from the cDNA library prepared from the left ovaries of one- to three-day-old chickens. The transcript corresponding to this cDNA clone is approx. 1.9 kb in length and is present in steroidogenic tissues (ovary, testis and adrenal gland) but is undetectable in non-steroidogenic tissues. Relative abundance of the transcript in the ovary and testis is high and developmentally regulated but is much lower in the adrenal gland. Relative levels of this transcript in the developing left ovary and the regressing right ovary of the one- to three-day-old chicken are similar. The nucleotide sequence of this cDNA clone shows significant homology to some mammalian cytochromes P-450. Out of the 508 amino acids (aa) coded, 244 and 243 aa residues are identical with those of the bovine and human cytochrome P-450c17 (steroid 17 alpha-hydroxylase/17,20 lyase), respectively. There are three highly conserved regions among the bovine, human and chicken sequences, one of which is unique to P-450c17. These data suggest strongly that this cDNA corresponds to the mRNA of a chicken cytochrome P-450c17.

Amino Acid Sequence↗
PubMed1988

Copper-induced hypercholesterolemia of golden hamsters: enhanced synthesis of cholesterol in the liver.

Effects of a subtoxic dose of copper on cholesterol metabolism were studied in male golden hamsters. Intraperitoneal injections of cupric acetate increased serum levels of cholesterol and phospholipids without liver damage. This lipidemia was associated with increased cholesterol of the liver. The participation of hemolysis was denied by peripheral red blood cell tests. Hepatic microsomal 3-hydroxy-3-methyl-glutaryl-CoA reductase was also elevated by copper administration. Biliary secretion of cholesterol increased but that of bile acids remained unchanged, suggesting no impaired degradation of cholesterol. We conclude that hepatic synthesis of cholesterol is enhanced by a subtoxic dose of copper, resulting in hypercholesterolemia.

Animals↗
PubMed1988

Efficacy of glucose, ouabain and an aldose reductase inhibitor on 2-[3H] myo-inositol uptake by human, rat and rabbit erythrocytes.

Myo-inositol uptake by erythrocytes from humans, rabbits and rats was studied with an isotope technique. In human erythrocytes, the inhibitory effect on myo-inositol uptake was stronger with glucose than with ouabain. However, an aldose reductase inhibitor (ONO-2235, 100 microM) or insulin (200 microU/ml) failed to correct the decrease in myo-inositol uptake in packed RBC, produced by either 10 mM glucose or 2mM ouabain. Ten mM ouabain had an inhibitory effect on myo-inositol uptake in all species, but an inhibitory effect was not observed with 20 mM glucose in rabbit erythrocytes. The results suggest that myo-inositol uptake by erythrocytes may be dependent on the active transport system via sodium-ATPase and that erythrocytes may not be a suitable model to monitor the possible effect of an aldose reductase inhibitor on myo-inositol concentrations in other tissues concerned with diabetic complications.

Aldehyde Reductase↗
PubMed1988

An outbreak of foodborne hepatitis A in a factory: a possible shift in age of patients in Japan.

We investigated extensively an outbreak of hepatitis A at a factory in suburban Nagoya. Epidemiological study indicated a foodborne outbreak by a supplier of lunches. Serologically, all the employees younger than 30 years of age had been susceptible to hepatitis A virus, but the highest morbidity was observed in the 40-44 age group. The age difference in morbidity from foodborne hepatitis and susceptible populations suggests a shift in mean patient age linked to a shift in antibody prevalence to hepatitis A virus. In communities where the prevalence started shifting after development of sanitary systems, effective prophylaxis for foodborne hepatitis A will be necessary to prevent the disease in an increasing number of older patients in a few decades.

Adult↗
PubMed1988

Relative contributions of the nervous system and hormones to CNS-mediated hyperglycemia.

We quantitatively determined the relative contributions of hormonal factors and the nervous system to the total glucose response after stimulation of the cholinergic neurons in the central nervous system of fed rats. Hepatic venous plasma glucose, glucagon, insulin, epinephrine, and norepinephrine were measured during 120 min after injection of neostigmine (5 X 10(-8) mol) into the third cerebral ventricle in rats subjected to bilateral adrenodemedullation (ADMX) to prevent epinephrine secretion (observed insulin secretion), with and without intravenous infusion of somatostatin to prevent glucagon and insulin secretion. Injection of neostigmine in intact rats resulted in increases in glucose, glucagon, epinephrine, and norepinephrine. Comparison of glucose areas suggests that 22% of the hyperglycemic response is due to the glucagon effect, that 29% is due to the epinephrine effect, and that an unknown factor other than epinephrine or glucagon, which may include activation through direct neural innervation of the liver via alpha-adrenergic receptor, contributes 49%. The suppressive effect of epinephrine on insulin secretion, which is potentially stimulated by direct neural activation of the pancreas, contributes 18% of the net hyperglycemia.

Adrenal Medulla↗
PubMed1988

The roles of glucagon and adrenal epinephrine in mediating hyperglycemia induced by third cerebroventricular injection of bombesin.

The roles of glucagon and adrenal epinephrine in mediating bombesin-induced central hyperglycemia were further studied in anesthetized rats. Bombesin (10(-9) mol) injected into the third cerebral ventricle produced an increase in plasma concentrations of glucose, glucagon, and epinephrine. Prior bilateral adrenalectomy completely prevented the hyperglucagonemic and hyperglycemic responses to third cerebral ventricle injection of bombesin. These results support the view that bombesin-induced increases in plasma glucose and glucagon are fully dependent on adrenal epinephrine secretion. Furthermore, during constant intravenous infusion of somatostatin, the hyperglycemic response to third cerebral ventricle injection of bombesin was not significantly influenced despite complete inhibition of the increase in plasma glucagon. Therefore, it is suggested that bombesin-induced central hyperglycemia is mainly mediated by epinephrine itself rather than via epinephrine-stimulated glucagon secretion.

Animals↗
PubMed1988

Possible involvement of diacylglycerol-activated, Ca2+-dependent protein kinase in glucose memory of the rat pancreatic B-cell.

Exposure to high concentrations of glucose potentiates insulin release from the pancreatic B-cell stimulated by various secretagogues after an interval under basal condition. We studied the role of diacylglycerol-activated, Ca2+-dependent protein kinase (protein kinase C) in this priming effect of glucose in rat pancreatic islets, using 12-O-tetradecanoyl phorbol-13-acetate (TPA), 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7),N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA-1004) and forskolin. The priming effect of glucose was mimicked by 10 nmol/l of TPA, an activator of protein kinase C, but not by 5 mumol/l of forskolin, which increases cAMP via activating adenylate cyclase. When pancreatic islets were exposed to glucose (10 mmol/l) together with 50 mumol/l of H-7, an inhibitor of protein kinase C, the secretory response to glucose (10 mmol/l) after a 30-min interval was significantly reduced compared with that in the islets previously exposed to 10 mmol/l glucose alone. In contrast, this was not the case for HA-1004, its inhibitory activity against protein kinase C being less potent than H-7. These findings suggest that protein kinase C may play an important role in the priming effect of glucose on the pancreatic B-cell.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1988

Central versus peripheral effect of clonidine on hepatic venous plasma glucose concentrations in fasted rats.

To evaluate whether clonidine exerts its action within the central nervous system or outside the central nervous system to induce hyperglycemia, we compared the effects of clonidine injected into the third cerebral ventricle or intravenously on hepatic venous plasma glucose concentrations in fasted rats. Clonidine administration produced a dose-dependent hyperglycemia in each case. At all tested doses (5, 50, and 100 nmol) the hyperglycemic responses to clonidine injected intravenously were not significantly different from those to clonidine injected into the third cerebral ventricle. Intraperitoneal pretreatment with yohimbine (50 nmol) or phentolamine (50 nmol), both alpha-adrenergic antagonists, reduced the hyperglycemic response to clonidine (100 nmol) given intravenously, but these antagonists preinjected into the third cerebral ventricle did not reduce the response. Moreover, no significant differences in venous plasma clonidine concentrations were observed when intravenous and third cerebral ventricle injections of clonidine (100 nmol) were compared. These results suggest that clonidine-induced hyperglycemia is mainly mediated by the peripheral mechanism rather than through the central mechanism. To gain an insight into the peripheral mechanism for the hyperglycemic action of clonidine, we measured the plasma immunoreactive glucagon and insulin concentrations after intravenous clonidine (100 nmol). We found that plasma immunoreactive glucagon concentrations significantly increased, whereas plasma immunoreactive insulin concentrations did not change significantly despite hyperglycemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Improvement of glucose tolerance in NIDDM by clofibrate. Randomized double-blind study.

A randomized double-blind study was performed to examine the effect of clofibrate on glucose tolerance in subjects with non-insulin-dependent diabetes mellitus (NIDDM). Clofibrate (1.5 g/day) or placebo was administered to 70 patients and an oral glucose tolerance test (OGTT) was performed before and 12 wk after treatment. Blood glucose levels were significantly improved in clofibrate-treated groups at all time points during OGTT, whereas there was no change in insulin levels. Improvement of fasting glucose levels required 8 wk of clofibrate treatment. Insulin binding to erythrocytes demonstrated no significant change in the clofibrate-treated subjects. These results suggest that clofibrate improves glucose tolerance in NIDDM subjects without a change in insulin receptors and that clofibrate increases insulin sensitivity through an unknown postreceptor mechanism.

Blood Glucose↗
PubMed1988

Enhancement of antibody production to hepatitis B surface antigen by interleukin 2.

Studies were undertaken to determine whether induction of antibody to hepatitis B surface antigen (anti-HBs) production by cultured lymphocytes which had been conducted with pokeweed mitogen (PWM) could be replaced by interleukin 2 (IL 2). In cultures stimulated with purified HBsAg and IL 2, the comparable levels of anti-HBs production to those obtained in cultures stimulated with PWM alone occurred when peripheral blood mononuclear cells (PBMC) from patients positive for serum anti-HBs and recipients of HBsAg vaccine were used as effector cells. Detectable amounts of anti-HBs were produced only when IL 2 was added to the second-set cultures again. IL 2 or HBsAg alone, however, did not induce anti-HBs production. Anti-HBs production was not observed by the additions of these additives when PBMC from chronic HBsAg carriers and control individuals were used. These findings indicate that IL 2 could modulate the immune response to HBsAg.

Carrier State↗