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Biomedical subjects

S Kasuga

Publications and source records attributed to S Kasuga.

At least 19 recordsLinked to original sources
PubMed2004

Temporal trends of organochlorine pesticides in prawn (Macrobrachium nipponense) from Lake Kasumigaura, Japan, during 1978-2000.

Temporal trends of organochlorine pesticides such as beta-hexachlorocyclohexane (beta-HCH), hexachlorobenzene (HCB), and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE), were determined in freshwater prawn (Macrobrachium nipponense) collected from Lake Kasumigaura in 1978 to 2000. The organochlorine pesticides elucidated a 72.4% decrease in beta-HCH, from 42 (1978) to 11.6 ng/g fat (2000); an 89.6% decrease in HCB, from 1.64 (1978) to 0.17 ng/g fat (2000); and an 87.3% decrease in p,p'-DDE, from 97.5 (1978) to 12.4 ng/g fat (1992). After organochlorine pesticide prohibition in 1971, the declining trend of beta-HCH, HCB, and p,p'-DDE concentrations persisting in the prawns could be approximated by exponential equations.

Animals↗
PubMed2004

Estimation of the density of nymphs of the bush tick, Haemaphysalis longicornis (Acari: Ixodidae), by the catch effort method.

The density of nymphs of the bush tick, Haemaphysalis longicornis, was investigated by the catch effort method with flagging. The spatial distribution of H. longicornis nymphs fit the model of contagiously distributed colonies by Iwao's m*-m analysis (Iwao 1968). A sequential sampling method was used to predict the theoretical point at which to stop sampling. Our analysis showed that five quadrats (4 m x 4 m) were sufficient to estimate the density of H. longicornis nymphs with a mean density of 5.39 per quadrat. We estimated the tick density by two methods with respect to the sampling interval. The estimated density of ticks based on ticks collected during short sampling intervals (within a half hour) was 511.34 in the 18 quadrats with the extrapolation of the linear regression equation. On the other hand, for the long interval sampling, the total number of ticks estimated by the linear regression equation was 635.47 in six quadrats in which ticks had been collected by long interval sampling. There was a significant difference between the slopes of the two linear regression equations, suggesting that the rate of reduction in the number of H. longicornis nymphs in the study area by the catch effort method differed between the two sampling methods.

Animals↗
PubMed2001

Prenatal stress and postnatal development of neonatal rats--sex-dependent effects on emotional behavior and learning ability of neonatal rats.

Maternal sound stress (800 Hz; 77 dB, every other minute for 15 min/day, from day 10 to 18 of gestation), combined with forced swimming stress (15 min/day), was found to cause potentiation of sound-induced loss of locomotor activity, referred to as emotional behavior, of male offspring, but not that of female offspring, at 4 weeks of age. Maternal stress also caused an increase in the total number of errors by male, but not female offspring in the water-maze test at 6 weeks of age. These effects of stress on emotional behavior and learning behavior were abolished when dams were pretreated with buspirone (30 min before the stress, from day 8 to 18 of gestation). Thus, prenatal stress might have sex-dependent effects on emotional behavior and learning ability of neonatal rats.

Acoustic Stimulation↗
PubMed2001

Comparison and evolution of the lagena in various animal species.

The structure of the vestibular organs of the teleost fish (bluegill), newts (Japanese fire-belly newt), frogs (black-spotted pond frog), snapping turtles and birds (chicks) was morphologically compared, with particular attention to the lagena macula, and the differences between animal species with relation to evolution were considered. Teleost fish had no striola on the lagena macula. The striola of newts were short and restricted to the central area of the macula, but those of frogs, snapping turtles and chicks extended from the anterior to posterior edges of the macula. This indicates that the frog is more highly evolved than the newt. The length of the kinocilium of sensory hairs was equal to that of the longest stereocilium in teleost fish and newts, but the kinocilia of frogs, snapping turtles and chicks were longer than the longest stereocilium. This indicates that the function of the lagena of teleost fish and newts is for hearing whilst in the other animals they are for posture. The diameter of the sensory hair bundles is small in teleost fish and frogs, but large in newts and snapping turtles. This indicates that the sensitivity of the sensory cells of the lagena towards outer force is low in teleost fish and frogs, high in newts and snapping turtles and intermediate in birds. The lagena of snapping turtles protrudes from the basilar papilla into the vestibule but the lagena of chicks lies on the tip of the long projecting basilar papilla. From observation of the locations of lagenae it is natural to speculate that there must have been some species of animal now extinct that had the evolving location of the lagena prior to that of chicks. In future it will be very interesting and useful to identify this extinct animal using DNA techniques.

Acoustic Maculae↗
PubMed2001

Immunomodulatory effects of aged garlic extract.

Using various kinds of models, we examined the effects of aged garlic extract (AGE) on immune functions. In the immunoglobulin (Ig)E-mediated allergic mouse model, AGE significantly decreased the antigen-specific ear swelling induced by picryl chloride ointment to the ear and intravenous administration of antitrinitrophenyl antibody. In the transplanted carcinoma cell model, AGE significantly inhibited the growth of Sarcoma-180 (allogenic) and LL/2 lung carcinoma (syngenic) cells transplanted into mice. Concomitantly, increases in natural killer (NK) and killer activities of spleen cells were observed in Sarcoma-180--bearing mice administered AGE. In the psychological stress model, AGE significantly prevented the decrease in spleen weight and restored the reduction of anti-SRBC hemolytic plaque-forming cells caused by the electrical stress. These studies strongly suggest that AGE could be a promising candidate as an immune modifier, which maintains the homeostasis of immune functions; further studies are warranted to determine when it is most beneficial.

Adjuvants, Immunologic↗
PubMed2001

Pharmacologic activities of aged garlic extract in comparison with other garlic preparations.

We investigated the pharmacologic activities of four garlic preparations, raw garlic juice (RGJ), heated garlic juice (HGJ), dehydrated garlic powder (DGP) and aged garlic extract (AGE). The study used three animal models, i.e., testicular hypogonadism (hypospermatogensis and impotence) induced by warm water treatment, intoxication of acetaldehyde and growth of inoculated tumor cells. RGJ was found to be effective only in recovery of testicular function. The efficacy of HGJ was observed in three models; however, it did not improve impotence. DGP was effective in recovery of spermatogenesis and stimulated acetaldehyde detoxification. Significant beneficial effects of AGE were found in all three models. Although all four garlic preparations significantly enhanced natural killer (NK) and killer cell activities of the spleen cells of tumor-bearing mice, only AGE and HGJ inhibited the growth of inoculated tumor cells. These results suggest that different types of garlic preparations have different pharmacologic properties, and among the four garlic preparations studied, AGE could be the most useful garlic preparation.

Acetaldehyde↗
PubMed2001

Effects of garlic preparations on the gastrointestinal mucosa.

The effects of garlic preparations, including dehydrated raw garlic powder (RGP), dehydrated boiled garlic powder (BGP) and aged garlic extract (AGE), on the gastric mucosa were determined using a newly established endoscopic air-powder delivery system, which can deliver solid materials directly into the stomach. Among the three preparations, RGP caused severe damage, including erosion. BGP also caused reddening of the mucosa, whereas AGE did not cause any undesirable effects. The safety of enteric-coated garlic products was also determined. Direct administration of pulverized enteric-coated products on the gastric mucosa caused reddening of the mucosa. When an enteric-coated tablet was administered orally, it caused loss of epithelial cells at the top of crypts in the ileum. These results suggest that caution be used with regard to safety and effectiveness when choosing a garlic preparation because some preparations may have undesirable effects, including gastrointestinal problems.

Animals↗
PubMed2001

Intake of garlic and its bioactive components.

The health benefits of garlic likely arise from a wide variety of components, possibly working synergistically. The complex chemistry of garlic makes it plausible that variations in processing can yield quite different preparations. Highly unstable thiosulfinates, such as allicin, disappear during processing and are quickly transformed into a variety of organosulfur components. The efficacy and safety of these preparations in preparing dietary supplements based on garlic are also contingent on the processing methods employed. Although there are many garlic supplements commercially available, they fall into one of four categories, i.e., dehydrated garlic powder, garlic oil, garlic oil macerate and aged garlic extract (AGE). Garlic and garlic supplements are consumed in many cultures for their hypolipidemic, antiplatelet and procirculatory effects. In addition to these proclaimed beneficial effects, some garlic preparations also appear to possess hepatoprotective, immune-enhancing, anticancer and chemopreventive activities. Some preparations appear to be antioxidative, whereas others may stimulate oxidation. These additional biological effects attributed to AGE may be due to compounds, such as S-allylcysteine, S-allylmercaptocysteine, N(alpha)-fructosyl arginine and others, formed during the extraction process. Although not all of the active ingredients are known, ample research suggests that several bioavailable components likely contribute to the observed beneficial effects of garlic.

Allyl Compounds↗
PubMed1999

Oxidative damage to mitochondrial DNA and its relationship to diabetic complications.

Increased oxidative stress induced by hyperglycemia may contribute to the pathogenesis of diabetic complications. Oxidative stress is known to increase the conversion of deoxyguanosine (dG) to 8-hydroxydeoxyguanosine (8-OHdG) in DNA, which is linked to increased mitochondrial DNA (mtDNA) deletions. We investigated mtDNA deletions and 8-OHdG in the muscle DNA of non-insulin-dependent diabetes mellitus (NIDDM) patients. mtDNA deletion of 4977 bp (delta mtDNA4977) and the content of 8-OHdG in the muscle DNA of the NIDDM patients were much higher than those of the control subjects. There was a significant correlation between delta mtDNA4977 and the 8-OHdG content (P < 0.0001). Both delta mtDNA4977 and the 8-OHdG content were also correlated with the duration of diabetes. Delta mtDNA4977 and the 8-OHdG content in muscle DNA increased in proportion to the severity of diabetic nephropathy and retinopathy. This is the first report that an increase in delta mtDNA4977 and 8-OHdG is proportional to the severity of diabetic complications. Oxidative mtDNA damage is speculated to contribute to the pathogenesis of diabetic complications though a defect in mitochondrial oxidative phosphorylation or other mechanisms. 8-OHdG and delta mtDNA4977 are useful markers to evaluate oxidative mtDNA damage in the diabetic patients.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

Prevention of psychological stress-induced immune suppression by aged garlic extract.

We determined the effect of Aged Garlic Extract (AGE) on damage caused to immune function by a psychological stress using a communication box. After four days of a psychological stress, a decrease in spleen weight and spleen cells was observed in the psychological stress-exposed mice as compared normal mice (non-stress). AGE significantly prevented the decreases in spleen weight and cells. Additionally, AGE significantly prevented the reduction of hemolytic plaque-forming-cells in spleen cells and anti-SRBC antibody titer in serum caused by this psychological stress. Moreover, a reduction in NK activities was observed in the psychological stress-exposed mice as compared with normal mice (non-stress), whereas NK activities in the AGE administered mice were almost the same as normal mice (non-stress). These results indicate that psychological stress qualitatively and quantitatively impairs immune function, and that AGE is extremely useful for preventing psychologically-induced damage.

Animals↗
PubMed1999

[Effect of aged garlic extract (AGE) on hyperglycemia induced by immobilization stress in mice].

The effect of aged garlic extract (AGE) on stress induced hyperglycemia was investigated using the immobilization stress model in mice. After the exposure to immobilization stress for 16 hr per day for 2 consecutive days, the adrenal glands of the mice hypertrophied, and their serum glucose level and corticosterone secretion became elevated, but insulin secretion did not change. These results suggest that the elevation of serum glucose was probably due to the stimulation of the pituitary-adrenocortical axis by the stress. Pretreatment of AGE (5 and 10 ml/kg, p.o.) significantly prevented adrenal hypertrophy, hyperglycemia and elevation of corticosterone, but did not alter serum insulin level. The efficacy of AGE was the same as that of diazepam (5 mg/kg, p.o.). From these results, it is suggested that AGE may prevent stress-induced hyperglycemia, which is the risk of suffering from diabetes mellitus and its progression.

Adrenal Glands↗
PubMed1998

The effects of coenzyme Q10 treatment on maternally inherited diabetes mellitus and deafness, and mitochondrial DNA 3243 (A to G) mutation.

The characteristic clinical features of diabetes mellitus with mitochondrial DNA (mtDNA) 3243(A-G) mutation are progressive insulin secretory defect, neurosensory deafness and maternal inheritance, referred to as maternally inherited diabetes mellitus and deafness (MIDD). A treatment for MIDD to improve insulin secretory defects and reduce deafness has not been established. The effects of coenzyme Q10 (CoQ10) treatment on insulin secretory response, hearing capacity and clinical symptoms of MIDD were investigated. 28 MIDD patients (CoQ10-DM), 7 mutant subjects with impaired glucose tolerance (IGT), and 15 mutant subjects with normal glucose tolerance (NGT) were treated daily with oral administration of 150 mg of CoQ10 for 3 years. Insulin secretory response, blood lactate after exercise, hearing capacity and other laboratory examinations were investigated every year. In the same way we evaluated 16 MIDD patients (control-DM), 5 mutant IGT and 5 mutant NGT subjects in yearly examinations. The insulin secretory response assessed by glucagon-induced C-peptide secretion and 24 h urinary C-peptide excretion after 3 years in the CoQ10-DM group was significantly higher than that in the control-DM group. CoQ10 therapy prevented progressive hearing loss and improved blood lactate after exercise in the MIDD patients. CoQ10 treatment did not affect the diabetic complications or other clinical symptoms of MIDD patients. CoQ10 treatment did not affect the insulin secretory capacity of the mutant IGT and NGT subjects. There were no side effects during therapy. This is the first report demonstrating the therapeutic usefulness of CoQ10 on MIDD.

Adult↗
PubMed1998

The process of otoconia formation in guinea pig utricular supporting cells.

In order to clarify the mechanism of otoconia formation, the pathway of calcium transport in the utricular supporting cells was investigated. Potassium pyroantimonate (PA) precipitation, which indicates the localization of calcium ions, was seen not only in otoconia but also in supporting cell cytoplasm. In the latter, deposits of PA were detected in the secretory granules and endoplasmic reticulum (ER). These deposits were not present in cells pretreated with ethylene glycol-O,O,-bis (2-aminoethyl)-N,N,N',N'-tetra-acetic acid (EGTA). Exposure of the supporting cells to streptomycin sulfate (SM) increased the number of lysosomes. These lysosomes contained many small deposits of PA. The remaining granules and ER in cytoplasm also contained small deposits of PA. The findings suggest that otoconia are formed by the vestibular supporting cells in which calcium ions might be transported via ER-secretory granule-lysosome-cytoplasmic protrusion.

Animals↗
PubMed1998

Mitochondrial deoxyribonucleic acid 3256C-T mutation in a Japanese family with noninsulin-dependent diabetes mellitus.

Accumulating reports indicate a relationship between mitochondrial DNA mutation and impaired glucose-induced insulin secretion leading to a subtype of noninsulin-dependent diabetes mellitus. DNA from a 45-yr-old Japanese woman with noninsulin-dependent diabetes mellitus and muscle atrophy was isolated and studied for mitochondrial DNA mutations. We identified a mitochondrial DNA C-T heteroplasmic mutation at nucleotide position 3256. The mutation was located in the transfer ribonucleic acidLeu in a region conserved in evolution. Eight other members of her family were examined for the mutation. Six of them had the same mutation together with noninsulin-dependent diabetes mellitus, and one teenage boy had the mutation and impaired glucose tolerance. The other family member who did not have this mutation had normal glucose tolerance. The enzyme activity of the mitochondrial oxidative phosphorylation pathway in the muscle of the proband was measured. The enzyme activity was decreased in the proband, especially in complex I. This mutation might be responsible for the abnormal glucose metabolism.

Adolescent↗
PubMed1998

Mechanisms of protection by S-allylmercaptocysteine against acetaminophen-induced liver injury in mice.

S-Allylmercaptocysteine (SAMC), one of the water-soluble organosulfur compounds in ethanol extracts of garlic (Allium sativum L.), has been shown to protect mice against acetaminophen (APAP)-induced liver injury. In this study, we examined the mechanisms underlying this hepatoprotection. SAMC (100 mg/kg, p.o.) given 2 and 24 hr before APAP administration (500 mg/kg, p.o.) suppressed the plasma alanine aminotransferase activity increases 3 to 12 hr after APAP administration significantly. The hepatic reduced glutathione levels of vehicle-pretreated mice decreased 1 to 6 hr after APAP administration, but SAMC pretreatment suppressed the reductions 1 to 6 hr after APAP administration significantly. These inhibitory effects of SAMC were dose-dependent (50-200 mg/kg) 6 hr after APAP administration. As SAMC pretreatment (50-200 mg/kg) suppressed hepatic cytochrome P450 2E1-dependent N-nitrosodimethylamine demethylase activity significantly in a dose-dependent manner, we suggest that one of its protective mechanisms is inhibition of cytochrome P450 2E1 activity. SAMC pretreatment also suppressed the increase in hepatic lipid peroxidation and the decrease in hepatic reduced coenzyme Q9 (CoQ9H2) levels 6 hr after APAP administration. The hepatic CoQ9H2 content of the SAMC pretreatment group was maintained at the normal level. Therefore, we suggest that another hepatoprotective mechanism of SAMC may be attributable to its antioxidant activity.

Acetaminophen↗