Mechanism by Which Magnesium Oxide Suppresses Tablet Hardness Reduction during Storage.

This study investigated how the inclusion of magnesium oxide (MgO) maintained tablet hardness during storage in an unpackaged state. Tablets were prepared with a range of MgO levels and stored at 40°C with 75% relative humidity for up to 14 d. The hardness of tablets prepared without MgO decreased over time. The amount of added MgO was positively associated with tablet hardness and mass from an early stage during storage. Investigation of the water sorption properties of the tablet components showed that carmellose water sorption correlated positively with the relative humidity, while MgO absorbed and retained moisture, even when the relative humidity was reduced. In tablets prepared using only MgO, a petal- or plate-like material was observed during storage. Fourier transform infrared spectrophotometry showed that this material was hydromagnesite, produced when MgO reacts with water and CO2. The estimated level of hydromagnesite at each time-point showed a significant negative correlation with tablet porosity. These results suggested that MgO suppressed storage-associated softening by absorbing moisture from the environment. The conversion of MgO to hydromagnesite results in solid bridge formation between the powder particles comprising the tablets, suppressing the storage-related increase in volume and increasing tablet hardness.

Taurine reduces the secretion of apolipoprotein B100 and lipids in HepG2 cells.

BACKGROUND: Higher concentrations of serum lipids and apolipoprotein B100 (apoB) are major individual risk factors of atherosclerosis and coronary heart disease. Therefore ameliorative effects of food components against the diseases are being paid attention in the affluent countries. The present study was undertaken to investigate the effect of taurine on apoB secretion and lipid metabolism in human liver model HepG2 cells. RESULTS: The results demonstrated that an addition of taurine to the culture media reduces triacylglycerol (TG)-mass in the cells and the medium. Similarly, cellular cholesterol-mass was decreased. Taurine inhibited the incorporation of [14C] oleate into cellular and medium TG, suggesting the inhibition of TG synthesis. In addition, taurine reduced the synthesis of cellular cholesterol ester and its secretion, suggesting the inhibition of acyl-coenzyme A:cholesterol acyltransferase activity. Furthermore, taurine reduced the secretion of apoB, which is a major protein component of very low-density lipoprotein. CONCLUSION: This is a first report to demonstrate that taurine inhibits the secretion of apoB from HepG2 cells.

Equilibrium intakes of calcium and magnesium within an adequate and limited range of sodium intake in human.

In the previous analysis of our human mineral balance studies, we demonstrated positive correlations between the balances of calcium (Ca) and magnesium (Mg) and sodium (Na) intake in the range of 3.06 and 4.06 g/d or 43.71 and 96.40 mg/kg body weight (BW)/d, but there was no correlation between Na intake and Na balance. This suggested that the balances of Ca and Mg are affected by Na intake. Therefore, in the current study, we recalculated equilibrium intakes for Ca and Mg when balances of their intakes and outputs were equal to zero within the above Na range to reduce the effects of Na intake. From 1986 to 2000, 90 volunteers (10 male, 80 female; age 18 to 28 y) took part in 9 mineral balance studies. The balance periods ranged from 8 to 12 d, with adaptation periods of 2 to 4 d. The dietary intakes of Ca and Mg ranged from 294 to 719 and 154 to 334 mg/d, or from 4.83 to 15.07 and 2.44 to 6.42 mg/kg BW/d, respectively. Intake of Ca significantly correlated with Ca balance (r2 = 0.268; p < 0.0001). When the balance was equal to zero, the mean value and upper limit of the 95% confidence interval for the regression equation between intake vs. balance were 10.072 and 10.660 mg/kg BW/d, respectively. Mg intake correlated significantly with Mg balance (r2 = 0.141, p = 0.003). When the balance was equal to zero, the mean value and upper limit of the 95% confidence interval for the regression equation between intake and balance were 4.078 and 4.287 mg/kg BW/d, respectively.

Sodium and potassium balances in Japanese young adults.

This study was conducted to estimate the requirements of sodium (Na) and potassium (K) in Japanese young adults. From 1986 to 2000, 109 volunteers (23 males, 86 females), ranging from 18 to 28 y old, took part in 11 mineral balance studies after written informed consent had been obtained. The duration of the study periods ranged from 5 to 12 d, with a 2-4 d adaptation period. Foodstuffs used in each study were selected from those commercially available. The Na and K content of the diet, feces, urine and sweat were measured by atomic absorption spectrophotometer. The results of a study in which Na intake was 6.87 g/d (ca. 300 mmol/d), the highest of all the studies, showed apparent positive Na balances. In contrast, another study in which Na intake was 2.21 g/d (ca. 100 mmol/d), the lowest of all the studies, showed apparent negative Na balances. These two studies seemed to differ from the other studies, as shown by regression equations calculated from either data of all the studies (n= 109) or data that did not include the two studies (n=90). The dietary intakes of Na and K ranged between 38.56-142.23 and 26.77-74.42 mg/kg body weight (BW)/d, or 2.21-6.87 and 1.83-3.61 g/d, respectively in the complete data, and 43.71-96.40 and 26.77-63.70 mg/kg BW/d, or 3.06-4.06 and 1.83-2.68 g/d, respectively in the data that did not include the two studies. The intakes of the two minerals were positively correlated. Na intake (Intake) was correlated positively with apparent absorption (AA) of Na, which was also correlated with Na urinary output (Urine). In the data that did not include the two studies, Na balance (Balance) was not correlated significantly with either Na Intake (r2=0.005) or AA of Na (r2=0.006). However, analysis of all the data showed a significant correlation between Na Balance and both Na Intake (r2=0.361) and AA of Na (r2=0.360). In the complete data, the mean value and upper and lower limits of the 95% confidence interval for the regression equation between Intake and Balance for Na, when balance was equal to zero (i.e mean, upper and lower limits), were 55.824, 60.787 and 50.862 mg/ kg BW/d, respectively. K Intake was correlated positively with AA of K, which was also correlated with both Urine K and K Balance. There was a significant correlation between K Intake and K Balance in both the complete data (r2=0.213) and the data that did not include the two studies (r2 = 0.116). In all the cases, mean, upper and lower limits for K were 39.161, 41.782 and 36.540 mg/kg BW/d, respectively. Intakes of Na and K did not correlate with their respective AA rates (%). Within the ranges of K Intake in this study, K Balance was affected markedly by K Intake itself as well as by Na Intake. However, in the case of Na, when the data of the highest and lowest Na intake studies were excluded from the analysis, Na Balance did not correlate with Na Intake, whereas the data of all the studies showed Na Balance was affected strongly by Na Intake. The data of this study allowed the estimated average requirements (EARs) for both minerals to be derived.

Positive correlation between dietary intake of sodium and balances of calcium and magnesium in young Japanese adults--low sodium intake is a risk factor for loss of calcium and magnesium--.

The content of calcium (Ca) and magnesium (Mg) in sweat during exercise is considerably higher during a relatively low intake of sodium (Na) of 100 mmol/d than with an intake of 170 mmol/d. For this reason and also because Ca and Mg have a negative balance with a Na intake of 100 mmol/d, we analyzed the relationship between Na intake and balances of Ca and Mg in data from 11 balance studies. From 1986 to 2000, 109 volunteers (23 males, 86 females) with an age range of 18 to 28 y took part in mineral balance studies. The balance periods ranged from 5 to 12 d. In a given experiment, the diet of each subject contained the same quantity of food, although this varied between experiments, and was supplied during the balance period without consideration of body weight. In the data of all the studies (n= 109), the balances of Ca and Mg did not correlate positively with Na intake. However, when the data of the highest Na study were excluded, the balances of Ca and Mg correlated positively with Na intake. The mean value for the regression equation between Na intake and Ca and Mg balances when the respective balance was equal to zero were, 63.308 mg Na/kg BW/d (Ca: n=96, r2=0.134) and 60.977 mg Na/kg BW/d (Mg: n=96, r2=0.268), respectively. These values are considerably higher than Na requirements estimated by inevitable Na loss. Low dietary Na may therefore be a risk factor for maintaining positive balances of Ca and Mg.

Taurine suppresses development of atherosclerosis in Watanabe heritable hyperlipidemic (WHHL) rabbits.

While the hypocholesterolemic effects of taurine have extensively been studied using experimental animals, the anti-atherosclerotic effects of taurine have been given less attention. We examined the effect of taurine on atherosclerotic lesions in Watanabe heritable hyperlipidemic (WHHL) rabbits. Treatment of WHHL rabbits with taurine (0.3% in drinking tap water) for 24 weeks decreased aortic lesions by 31%, estimated as intimal thickening. Taurine significantly decreased cholesteryl ester content of aortic arch, thoracic aorta, and abdominal aorta by 35, 43, and 54%, respectively. Concomitantly, activity of acyl-CoA:cholesterol acyltransferase (ACAT), an enzyme responsible for cholesterol esterification, was also significantly decreased. Immunohistochemical analysis revealed decreased macrophages in the intima of taurine-treated rabbits. Taurine had no apparent effect on blood pressure and serum cholesterol levels. Contents of thiobarbituric acid reactive substances (TBARS), a marker of lipid peroxidation, was reduced in serum and aorta by 29 and 50%, respectively, when taurine was ingested. In addition, LDL from taurine-treated rabbits was resistant to copper-induced oxidative modification. These results revealed that taurine prevents development of atherosclerosis and that the anti-atherosclerotic effects of taurine are independent of serum cholesterol levels. The anti-oxidant action of taurine may be involved in inhibiting atherosclerosis in these rabbits.

Effect of taurine on cholesterol metabolism in hamsters: up-regulation of low density lipoprotein (LDL) receptor by taurine.

The effects of taurine on hepatic cholesterol metabolism were investigated in hamsters fed a high-fat diet or normal chow. Two weeks-treatment of taurine at 1% in drinking water prevented high-fat diet-induced increase in cholesterol levels of serum and liver. The decrease in serum cholesterol by taurine was due to decrease in non-HDL cholesterols. A similar tendency was noted in serum and liver cholesterol levels of hamsters fed a normal diet. In hamsters fed a high-fat diet, taurine prevented elevation in hepatic activity of acyl-CoA:cholesterol acyltransferase (ACAT) and increased the activity of cholesterol 7alpha-hydroxylase. Taurine also increased cholesterol 7alpha-hydroxylase activity in hamsters fed normal chow. Studies on liver membranes revealed that taurine increased 125I-labeled LDL binding by 52% and 58% in hamsters fed either a normal chow or high-fat diet, respectively. Furthermore, LDL kinetic analysis showed that taurine intake resulted in significant faster plasma LDL fractional catabolic rates (FCR). These results suggest that taurine elevates hepatic LDL receptor and thereby decreases serum cholesterol levels, an event which may be the result of hepatic cholesterol depletion as a consequence of increased bile acid synthesis via enhancement of cholesterol 7alpha-hydroxylase activity. Thus, up-regulation of the LDL receptor and subsequent increase in receptor- mediated LDL turnover may be a key event in the cholesterol-lowering effects of taurine in hamsters.

Effect of dietary amino acids on behavior and serum levels of amino acids in stress loaded rats.

Interrelationships between behavior and concentrations of serum amino acids in stressed rats with immobilization and water immersion were investigated. Rats were subjected to 7 h of immobilization with water-immersion stress (IWS) in each sequential day, and serum amino acids were then determined. On the first day, serum taurine, threonine, valine, leucine, isoleucine, phenylalanine, lysine, and histidine (increased-type of amino acids) were significantly increased, but alanine (decreased-type) was significantly decreased. On days 3 and 7, the increase was retained, except for threonine, histidine, and lysine. Spontaneous activities (locomotion, rearing behavior, hole-poking) under loading water-immersion stress were significantly decreased, but a supplementation of branched-chain amino acids (BCAA) led to recovery. We suggest that pretreatment with some kind of increased type of amino acid, such as BCAA, might effectively prevent decline in spontaneous activities evoked by water-immersion stress.

Co-administration of proline and inorganic iron enhance the improvement of behavioral and hematological function of iron-deficient anemic rats.

We investigated the interrelationships between behavior and serum amino acid concentrations in iron-deficient anemic rats. Concentrations of proline, alanine, glycine, and phenylalanine in serum samples were significantly higher than those in rats fed a normal diet, while serum threonine, glutamic acid, and valine levels were significantly lower. Activities of locomotion, rearing, hole-poking, and grooming, determined by using a hole board apparatus, were significantly reduced in anemic rats. The supplementation of inorganic iron and amino acids proline, arginine, or glutamic acid to the normal diet lead to the recovery of normal behavior. Proline enhanced a significant increase in the number of red blood cells and hemoglobin by the supplementation of iron alone. We propose that the combination of amino acid (especially proline) and inorganic iron might lead to an improvement in behavioral disorders caused by iron-deficient anemia.

Balances of calcium, magnesium and phosphorus in Japanese young adults.

This study was conducted to estimate the requirements of calcium (Ca), magnesium (Mg) and phosphorus (P) in Japanese young adults. From 1986 to 2000, 109 volunteers 123 males, 86 females), ranging from 18 to 28 y old, took part in mineral balance studies after written informed consent was obtained. The duration of the study periods ranged from 5 to 12 d, with 2-4 d of adaptation. Foodstuffs used in each study were selected from those commercially available. The minerals present in diet, feces, urine and sweat were measured by atomic absorption spectrophotometer (Ca, Mg) or spectrophotometer (P). The dietary intakes of Ca, Mg and P ranged from 4.83-23.58, 2.44-7.83 and 13.46-45.69 mg/ kg BW/d, respectively. Dietary intake (Intake) of Ca was positively correlated to apparent absorption (A.A.) (r2 = 0.425), which was also correlated with urine excretion (Urine) (r2 = 0.327) and balance (Bal) (r2 = 0.382). Intake of Ca was slightly but significantly correlated with Bal (r2 = 0.036, p = 0.048). The mean value and upper limit of the 95% confidence interval for the regression equation between Intake and Bal when balance is equal to zero (Mean and upper limit) for Ca were 11.752 and 12.555 mg/kg BW/d, respectively. Intake of Mg was positively correlated to A.A. (r2 = 0.451), which was also correlated with Urine (r2 = 0.486) and Bal (r2 = 0.349). However, Intake of Mg was not correlated with Bal. Intake of P was positively correlated with A.A. (r2 = (0.959), which was also correlated with both Urine (r2 = 0.908) and Bal (r2 = 0.135). Intake of P was slightly but significantly correlated with Bal (r2 = 0.103, p = 0.0013). Mean and upper limits for P were 22.584 and 24.059 mg/kg BW/d, respectively. Intakes of Mg and P correlated negatively with their respective A.A. rates (%) (r2 = 0.120 for Mg, r2 = 0.109 for P). However, there was not much of a correlation for Ca. Balance of Ca was positively correlated with that of Mg (r2 = 0.541), but not with that of P.

Balance of magnesium positively correlates with that of calcium.

BACKGROUND AND OBJECTIVE: In a prior study, we showed no significant relationship between intake and balance of magnesium (Mg). Subsequent further investigation disclosed that intakes of both Ca and P were positively correlated with their respective balances, whereas intake of Mg did not show any significant correlation with Mg balance. In this paper, we show positive correlations between intake of Mg and balances of both Ca and P. METHODS AND RESULTS: Using these correlations, the mean value and upper limit of the 95% confidence interval (from the regression equation between Mg intake and either the balances of Ca or that of P, when each balance is equal to zero) were 4.584 and 4.802 (against Ca balance), 4.554 and 4.785 (against P balance) mg/kg BW/d, respectively. Balances of Mg and Ca correlated with each other.