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Biomedical subjects

Y Itokawa

Publications and source records attributed to Y Itokawa.

At least 19 recordsLinked to original sources
PubMed2001

The effect of aging on the mineral status of female SAMP1 and SAMR1.

The effect of aging on the status of macrominerals and trace elements in tissues was studied using two strains (SAMP1 and SAMR1) of senescence accelerated mouse. Two-month-old, 6-mo-old, and 10-mo-old female SAMP1 and SAMR1 mice were fed a commercial diet. Iron, zinc, copper, calcium, magnesium, phosphorus, sulfur, sodium, and potassium concentrations in blood, liver, kidney, brain, and tibia of the mice were determined. The copper concentration in the brain was significantly increased with age in SAMP1 and SAMR1. In addition, the brain copper levels in SAMP1 were significantly higher than that in SAMR1 at respective ages. The calcium concentration in the kidney was significantly increased with age, but the copper and phosphorus concentrations significantly decreased with age in SAMP1 and SAMR1. In the liver of SAMR1, all minerals measured in this study except for sodium and potassium were significantly decreased with age. In addition, all mineral concentrations in the liver of 2-mo-old mice in SAMR1 except for copper and sodium were markedly higher than those in SAMP1 of the same age. These results suggest that the genetic factor is related to the age-associated mineral changes in tissues.

Aging↗
PubMed2000

[Alcohol intake and nutrition].

This article contains summaries of our studies carried out at the society of the research "alcohol and health" with discussions on some related studies. Items included: (1) Discussions on "could alcoholic beverage regard as a nutrient?". (2) Nutrients in alcoholic bevarages. Distilled alcoholic beverages contain little nutrients except energy, while brewered alcoholic beverages contains nutritionally significant amounts of magnesium, niacin, and vitamin B2. (3) Dietary habits and alcoholics. Survey studies on researchers working at a brewing industry revieled that positive correlations were observed between intakes amounts of alcoholic beverages and intakes amounts of pulses, fishes, eggs, and seasonings and spices. While, negative correlations were observed between intake amount of confectioneries, fruits and daily products, and intake amount of alcohol. As nutrients, intakes of energy and sodium increased and intakes of dietary fibers, niacin, vitamin C, carotene, and zinc decreased in proportion to increase in alcoholic intakes. (4) Effect of alcohol intake on metabolism of nutrients. To clarify the influence of alcohol intake on nutrients metabolism, our research group carried out several animal experiments. Thiamin status evaluated by blood thiamin level and erythrocyte transketolase activity a thiamin dependent enzyme, decreased significantly by excess administration of alcohol. Effect of alcohol on metabolism of zinc, a cofactor of alcohol dehydrogenase, was not significant in our experiments, although other researchers reported that zinc metabolism was influenced by alcohol intake. In addition, we found that copper concentration in liver decreased significantly in alcohol administered rats as compared to control rats. The mechanisms concerning alcohol intakes on copper metabolism remains to be clarified.

Alcohol Drinking↗
PubMed1999

Proposed standard for human blood vitamin B1 value using HPLC. The Committee for Vitamin Laboratory Standards, Japan.

Standard reference ranges for all laboratory test values are mandatory. This study was designed to establish a reference range for blood vitamin B1 levels, since the normal range has not been determined in the Japanese population. We founded the Japan Committee for Vitamin Laboratory Standards, which was incorporated with the Vitamin Society of Japan and the Japanese Society of Nutrition and Food Science. We standardized whole blood vitamin B1 levels using three HPLC techniques (post-column reverse-phase HPLC, pre-column reverse-phase HPLC, and precolumn GP-HPLC). The reference range was obtained in 54 volunteers administered a 1,800 kcal diet with 2 mg of vitamin B1 (1.74 mg measured) daily to avoid marginal vitamin B1 deficiency in the population. The range for each assay was 26-47, 28-51, and 28-56 ng/ml, respectively. Our data suggest that 26-28 ng/ml is the lower limit of normal for whole blood vitamin B1, but further studies in a larger population are needed in order to obtain more definitive results.

Chromatography, High Pressure Liquid↗
PubMed1999

Testicular atrophy, zinc concentration, and angiotensin-converting enzyme activity in the testes of vitamin A-deficient rats.

Angiotensin-converting enzyme (ACE) as a part of the renin angiotensin system (RES) regulates blood pressure and fluid and electrolyte homeostasis, and the enzyme is considered to have a function in reproduction. Reduced enzyme activities have been observed in atrophied testes as a results of zinc and pituitary deficiencies. Vitamin A deficiency causes atrophy of testes. The present study was conducted on three groups of male, 3-wk-old, Wistar rats. After 54 d of the experimental period, testicular weights of the vitamin A-deficient rats (A- group, allowed free access to vitamin A- deficient diet) was significantly lower than its pair-fed, PF (given restricted amount control diet) and A+ (allowed free access to control diet) groups. Zinc concentrations and both soluble and particulate ACE activities in the testes of vitamin A- deficient rats (A- group) were significantly lower than the other two groups. No significant differences were observed regarding zinc concentration, particulate ACE, and total ACE activities in the testes of PF and A+ groups. Vitamin A deficiency did not significantly affect the enzyme activity in the lung. From the observations of the present study, we speculate that testicular atrophy in vitamin A deficiency may have resulted from lower zinc concentration and decreased ACE activity in that organ.

Animals↗
PubMed1999

The relationship between thiamine deficiency and performance of a learning task in rats.

We have been investigating the relationship between learning and thiamine. Electrical stimulation of mesencephalic periaqueductal gray matter (PAG) is known to have an aversive effect and elicits spontaneous instrumental escape behavior. We taught rats to press a lever to escape from the pain of electrical stimulation by learning to turn a switch off. Then we examined the relationship between learning and the thiamine concentration in various portions of the brain. (1) One group of rats was given a normal diet and another group was given a thiamine-deficient diet which contained half of the amount of thiamine present in the normal diet. We measured the response time required for each rat to react by moving after an electrical impulse was applied, and the running time during which the rat was moving from the starting point to the end point to press a lever. The rats that were fed the thiamine-deficient diet showed a slower response time and a longer running time than the rats fed the normal diet. (2) We divided the rats fed the normal diet into two groups, one group trained to switch off a lever and the other group not trained for such a task. We found that the thiamine concentration in the blood of the rats in the trained group was significantly higher than that in the group without training.

Animals↗
PubMed1999

Effects of taste stimulation on the behavior of serum amino acid concentrations and amylase and trypsin activities in fasting rats.

The effect of taste stimulation on serum free-amino acid concentrations and amylase and trypsin activities in fasting rats was studied. Following an acclimation period of 5 d, male Sprague-Dawley rats were fasted for 4 d and sacrificed after taste stimulation with a palatable sodium saccharin or unpalatable quinine sulfate flavored diet. Blood was collected from the portal vein and inferior vena cava at 0, 5, 10, 20 and 30 min after taste stimulation. Intestinal contents were also collected at the same time intervals as the blood collections. Total amino acid concentrations in the saccharin stimulated group increased significantly at 5 and 20 min following taste stimulation in comparison with the control of 0 time in the portal vein, and a significant difference between the saccharin and quinine stimulated groups was also observed at 5 min. No difference was found in the inferior vena cava. A high level of alanine and low level of glutamine were depicted in the portal vein as compared to that of the inferior vena cava. The elevation of alanine that is gluconeogenic amino acid was remarkable in the saccharin group at 20 min in the portal vein. Moreover, amylase and trypsin activities in the saccharin group reached peak values promptly and kept constant throughout the experiment as compared to the quinine group. The results suggest that taste stimulation originates changes in the cephalic phase amino acid concentrations in the portal vein and that taste information, overcoming a hunger, plays an important role in amino acid metabolism and digestive enzyme activities. Therefore, eating with gusto is significant for the maintenance of body functions even under starvation conditions.

Amino Acids↗
PubMed1999

[Clinical vitaminology].

This paper deals with overview on clinical vitaminology including as follows: 1. Historical trends of prevalence of vitamin deficiency in Japan. 2. Recent status of number of patient with vitamin deficiency referred to "patients survey" by Ministry of Health and Welfare. 3. Notion and characteristic of vitamin dependency. 4. Types of vitamin deficiency. i.e. a simple type and a tape caused by disturbance of utilization. 5. Vitamin metabolism of hospitalized elderly patients. 6. Pharmacological role of vitamins.

Adult↗
PubMed1998

Influence of selenium deficiency on vital functions in rats.

To clarify the relationship between selenium (Se) deficiency and functional disorders, the authors determined the Se concentration, anti-oxidant enzyme activity, and other parameters in rats fed a Se-deficient diet. Rats fed the Se-deficient diet showed a decrease in Se concentration and glutathione peroxidase (GSH-Px) activity in plasma, erythrocytes, heart, liver, and skeletal muscle from the first week after the initiation of the diet, an increase in heart lipid peroxide concentration from the second week, and an increase in liver glutathione S-transferase activity from the fourth week. From the twelfth week, a decrease in the growth rate in the rats fed the Se-deficient diet was observed. In spite of this growth impairment, no changes in electrocardiogram, muscle tone, degree of hemolysis, plasma biochemistry, or hematological values were detected. In summary, the authors found that a reduction of body Se is easily induced, but that the appearance of functional disorders following Se deficiency is difficult to detect in rats.

Animals↗
PubMed1998

Psychological studies of a Japanese winter-over group at Asuka Station, Antarctica.

In order to understand the psychological effects of Antarctic isolation and confinement on Japanese expeditioners, psychological studies were done on eight members of a wintering-over party at Asuka Station between December 1990 and February 1992. Mean age of the subjects was 34.8 +/- 5.56 yr. The study includes self assessment questionnaires, psychological tests introduced by the Polar Psychology Project (PPP), a bibliographical study and photographic measurements. There was no pathological depression in midwinter. Subjective and cumulative fatigue symptoms were more noticeable in the older individuals. The Telic Dominance Scale was significantly correlated with the Anxiety Sensitivity Index. The Sense of Coherence Inventory and the Personal View Survey showed an interrating correlation. By analyzing a daily group photograph, seasonal variations in mood and behavior of individuals have been clarified. Consequently, it is hoped that observation of non-verbal signals such as facial expression, clothing, and postures may lead to the development of a new methodological framework for the long-term plan of psychological investigation of the men under severe stress.

Adult↗
PubMed1997

The decrement of carcinogenesis by dietary selenium and expression of placental form of glutathione-S-transferase in rat glioma.

Supranutrition dietary levels of the element selenium (Se) that have been shown to reduce or retard tumor development resulting from transplantation. The rat placental form of glutathione-S-transferase (GST-p) has been reported to be a good marker for pre-neoplastic or neoplastic lesions. Four groups of rats with glioma were exposed to Se-free, 0.05, 2.0, and 4.0 ppm sodium selenite GST-p was investigated. Normal brain tissue did not differ significantly in all groups. In contrast, GST-p in tumor was significantly higher in Se-free and 4.0-ppm groups compared to 0.5- and 2.0-ppm groups. The concentration of Se in normal brain tissue did not differ significantly in Se-supplement groups. By contrast, Se in tumors was significantly higher in the 0.5- and 2.0-ppm groups compared to the Se-free and 4.0-ppm groups. Mean group survival at 30 d after treatment was determined and compared with previous dietary Se. Survival was significantly longer in the 0.5- and 2.0-ppm groups than in the Se-free and 4.0-ppm groups. The 2.0-ppm group had enhanced survival, similar to the 0.5-ppm group. The Se-free and 4.0-ppm groups might have no protection against carcinogenesis.

Animals↗
PubMed1997

Influence of selenium deficiency on the acute cardiotoxicity of adriamycin in rats.

The influence of selenium (Se) deficiency on the acute cardiotoxicity induced by the anticancer drug adriamycin (ADR) has been studied in rats by electrocardiography. Two categories were formed by feeding groups of rats a Se-supplemented and a Se-deficient diet. The supplemented animals were taken as normals. The two categories were treated with iv injections of saline solution containing ADR at doses of 0, 7.5, and 15 mg/kg body wt. The cardiac Se concentration and glutathione peroxidase (GSH-Px) activity in the Se-deficient groups were < 2% lower than in the normals. The normal groups showed significant widening of the SaT and QaT durations when given 15 mg/kg ADR. The Se-deficient groups exhibited a dose-dependent widening of the SaT and QaT duration at 7.5 and 15 mg/kg and narrowing of the PQ duration at 15 mg/kg ADR. No heart rate or QRS duration changes were detected in both categories. Our results suggest that an imbalance of the antioxidant system is associated with Se deficiency and that Se plays a role in preventing the cardiac functional disorder attributable to oxygen free radical formation induced by ADR.

Animals↗
PubMed1997

Changes in iron, calcium, magnesium, copper, and zinc levels in different tissues of riboflavin-deficient rats.

To clarify the changes of mineral levels in different tissues of riboflavin-deficient rats, Wistar rats were separated into three groups. One group was fed a diet ad libitum that was deficient in riboflavin. The other two were fed either the complete diet that was weight-matched to the riboflavin-deficient group or fed a complete diet ad libitum. In riboflavin-deficient rats, the hemoglobin concentration and riboflavin contents of blood, liver, and kidney were significantly decreased, compared with weight-matched and ad libitum-fed controls. The mineral concentrations of tissues are summarized as follows: The iron (Fe) concentration in the heart, liver, and spleen was decreased in the riboflavin-deficient group compared with the other groups. Calcium (Ca) and magnesium (Mg) concentrations in tibia were decreased in the riboflavin-deficient group compared with the other two groups. Copper (Cu) concentration was increased in the heart and liver, when the riboflavin-deficient group was compared with the other groups. Zinc (Zn) concentration was increased in tibia when the riboflavin-deficient group was compared with the other groups.

Animals↗
PubMed1997

Springtime peaks of trace metals in Antarctic snow.

Drifting snow samples were collected at Asuka Station (71 degrees 32'S, 24 degrees 08'E, 930 m above sea level) over a period from July to December 1991; 36 elements (including Na, Mg, K, Ca, Fe, Al, Li, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Se, Rb, Sr, Cd, Pb, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th) in snow were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) by direct sample introduction. Concentrations of Cl-, NO3-, and SO(4)2- in the snow were also determined by ion chromatography. In late September to early October, there was a pronounced peak concentration of most of the elements together with non-sea salt sulfate. Enrichment factor analyses suggest that Na, Mg, Ca, K, and Sr are of marine origin and Al, Fe, Mn, Rb, Cr, Ni, Ga, V, and all the rare earth elements are of crustal origins. Volcanic eruption of Mt. Pinatubo (June 1991) and Mt. Hudson (August 1991) could be the reason for the precipitation of Pb, Cd, Cu, Zn, and Se together with non-sea salt sulfates in the austral spring at Asuka Station.

Meteorological Concepts↗
PubMed1997

Selenium level and glutathione peroxidase activity in plasma, erythrocytes and platelets of healthy Japanese volunteers.

The purpose of this study was to determine both the selenium (Se) level and glutathione peroxidase (GSH-Px) activity in plasma, erythrocytes and platelets from 51 healthy Japanese individuals. The Se levels (mean +/- SD) of plasma, erythrocytes and platelets were 117.4 +/- 15.7 micrograms/L, 0.954 +/- 0.159 microgram/g hemoglobin, and 4.93 +/- 1.52 ng/mg protein, respectively, and GSH-Px activity was 318 +/- 50 U/L, 18.0 +/- 5.0 U/g hemoglobin, and 0.142 +/- 0.035 U/mg protein, respectively. There was a negative correlation between age and the platelet Se level in men (r = -0.761, p < 0.001), and a positive correlation between the plasma and platelet GSH-Px activities in women (r = 0.663, p < 0.001).

Adult↗
PubMed1997

[Trial of radiation and cisplatin, carboplatin combination chemotherapy for advanced cancer (W-platinum chemoradiotherapy].

Cisplatin was reported to be an effective radiation sensitizing agent. The effect was also reported to depend on dose intensity. But the incidence of complication was demonstrated in the relationship with the dose escalation curve of anti-cancer agent. The major side effect of CDDP was occasionally serious, as in renal toxicity or bone marrow suppression. W-Platinum is the trial of concurrent chemoradiotherapy. Cisplatin and its derivative, Carboplatin, were selected as effective radiation sensitizing agents and to obtain high-dose intensity and additive cytotoxicities by interaction between the two drugs. Concomitant administration of two platinum anti-cancer agents has the advantage of reduction of side effects compared with administration of single anti-cancer agents to the same degree. The first case was a recurrence of epipharyngeal cancer after 3 courses of chemotherapy, including CDDP or CBDCA. This case was suspected to be cancer-resistant to CDDP. The second case was post-operative residual lung cancer. The pre-operative diagnosis was stage III A. A poor prognosis was expected. This case was disease-free and alive for 1 year after W-Platinum administration. The most frequent complication was bone marrow suppression. Patients were rescued from bone marrow suppression with administration of G-CSF. Renal toxicity could be suppressed with sufficient hydration.

Adenocarcinoma↗
PubMed1996

Effects of thiamine supplementation on exercise-induced fatigue.

High-dose thiamine (vitamin B1) supplementation (100 mg/day) may be helpful in preventing or accelerating recovery from exercise-induced fatigue. Sixteen volunteer male athletes volunteer, 8 with a blood thiamine level of 40 ng/ml or more (normal thiamine group) and 8 with levels below that level (low thiamine group) were selected as subjects. They exercised on a bicycle ergometer and the effects of thiamine supplementation were compared with placebo. Blood thiamine level markedly increased following supplementation of thiamine for 3 days before exercise. Exercise-induced changes in hemodynamic parameters and cardiopulmonary function indicated the onset of fatigue. Thiamine supplementation significantly suppressed the increase in blood glucose in the normal thiamine group and significantly decreased the number of complaints shortly after exercise in the subjective fatigue assessment of 30 items.

Adult↗