Studies on the Inhibition of Intestinal Absorption of Radioactive Strontium: V. The Effect of Administration of Calcium Alginate

A method of selective suppression of absorption of radioactive strontium from ingested food material is described which allows calcium to be available to the body. In the present study the effects of administering calcium alginate were determined. Studies on the relative binding of Ca and Sr by calcium alginate in vivo are also important to the investigation of calcium-strontium exchange.Samples of calcium alginate were obtained commercially or prepared from sodium salts and the binding properties with Ca⁴⁵ and Sr⁸⁹ were tested in vivo. There was a free exchange of radioactive calcium as well as of strontium with bound inactive calcium. The amount of Ca⁴⁵ retained in the gut by calcium alginate is proportionally less than Sr⁸⁹, so that the ratio Sr⁸⁹/Ca⁴⁵ in the bone is consistently and significantly lower in treated rats. Calcium alginate acts differently from other calcium salts, although in a manner similar to sodium alginate.     

Studies on the Inhibition of Intestinal Absorption of Radioactive Strontium: III. The Effect of Administration of Sodium Alginate in Food and in Drinking Water

A method is reported which permits selective suppression of absorption of radioactive strontium from ingested food material, permitting calcium to be available to the body. Studies were carried out by measuring bone uptake of Sr⁸⁹ and Ca⁴⁵ when various amounts of sodium alginate were fed with the diet. Long-term studies were made in which two different levels of radioactivity were used, to determine the pattern of Sr⁸⁹ deposition with continuous intake of binding agent. It was found that administration of sodium alginate as a jelly overcomes the problem of constipation and effectively reduces Sr⁸⁹ uptake, up to 83%. This fact represents a significant finding with respect to the use of the compound in human subjects. Addition of sodium alginate to drinking water is effective with low levels of Sr⁸⁹ intake.This naturally occurring water-soluble macromolecular substance possesses several advantages in use for the suppression of absorption of radioactive strontium when compared with synthetic ion exchange resins: there is no disturbance of electrolyte balance; efficiency is not reduced by treatment over a prolonged period of time; and finally, the product is palatable.     

Studies of Inhibition of Intestinal Absorption of Radioactive Strontium: IV. Estimation of the Suppressant Effect of Sodium Alginate

A method is reported which permits selective suppression of absorption of radioactive strontium from ingested food material, allowing calcium to be available to the body. Studies were carried out on the inhibitory effect of various amounts of sodium alginate and the dose-response relationship of Sr⁸⁹ and bone uptake. The results obtained indicated that under laboratory conditions sodium alginate effectively reduces Sr⁸⁹ uptake in a constant proportion. This effect was observed at the three levels of administration of 1.4%, 12% and 24% of sodium alginate. The linear relationship between the dosage of the radioisotope and the bone uptake in the presence of sodium alginate suggests that the same proportion is maintained at the lower levels of intake of radioactive strontium.Previous studies with small constant doses of sodium alginate were extended in rats to a period corresponding approximately to three years of human life span. Low doses were sufficient to reduce appreciably bone uptake of radiostrontium.     

Metabolism and Calcium Antagonism of Sodium Alginate Oligosaccharides

Sodium alginate oligosaccharides (NaAOs) consisting of a mixture of eight oligosaccharides have previously been reported to lower blood pressure. We investigated in this study the excretion of NaAOs into the urine or feces, and attempted to elucidate the mechanism for lowering blood pressure by using isolated mesenteric arteries from the rabbit. The recovery rate of P8, which is the main component of NaAOs, was 5.2% and 58.9% over 48 hours in the urine and feces, respectively. The mechanism for lowering blood pressure appeared to be NaAOs having calcium antagonist activity, especially voltage-operated calcium channels. Our results suggest that NaAOs are substantially excreted into the feces, although some of them may be absorbed internally, exerting antagonist activity towards the calcium channels, especially voltage-operated calcium channels.     

Relevance of Rheological Properties of Sodium Alginate in Solution to Calcium Alginate Gel Properties

The purpose of this study is to determine whether sodium alginate solutions’ rheological parameters are meaningful relative to sodium alginate’s use in the formulation of calcium alginate gels. Calcium alginate gels were prepared from six different grades of sodium alginate (FMC Biopolymer), one of which was available in ten batches. Cylindrical gel samples were prepared from each of the gels and subjected to compression to fracture on an Instron Universal Testing Machine, equipped with a 1-kN load cell, at a cross-head speed of 120 mm/min. Among the grades with similar % G, (grades 1, 3, and 4), there is a significant correlation between deformation work (L _E) and apparent viscosity (η _app). However, the results for the partial correlation analysis for all six grades of sodium alginate show that L _E is significantly correlated with % G, but not with the rheological properties of the sodium alginate solutions. Studies of the ten batches of one grade of sodium alginate show that η _app of their solutions did not correlate with L _E while tan δ was significantly, but minimally, correlated to L _E. These results suggest that other factors—polydispersity and the randomness of guluronic acid sequencing—are likely to influence the mechanical properties of the resultant gels. In summary, the rheological properties of solutions for different grades of sodium alginate are not indicative of the resultant gel properties. Inter-batch differences in the rheological behavior for one specific grade of sodium alginate were insufficient to predict the corresponding calcium alginate gel’s mechanical properties.     

Studies on Inhibition of Intestinal Absorption of Radioactive Strontium: II. Effects of Administration of Sodium Alginate by Orogastric Intubation and Feeding

A method is reported that enables selective suppression of absorption of radioactive strontium from ingested food material, permitting calcium to remain available to the body. Studies were carried out by measuring blood levels and bone uptake of Sr⁸⁹ and Ca⁴⁵ at different time intervals after orogastric intubation of rats. The addition of sodium alginate, derived from brown marine algae, to the radioactive isotopes increased the overall physiological discrimination against strontium by amounts up to 60% after 24 hours. This discrimination was further increased by feeding sodium alginate mixed with standard diet in the proportions of 20:80 and 30:70. The observed ratio was reduced by administration of sodium alginate from 0.25 to 0.09.Determination of the limiting dosage in rats is restricted to the amounts which rats will consume. In the event of an inadvertent release of radioactive strontium, human subjects probably could increase their intake of alginate at will, permitting a greater effectiveness of sodium alginate than could be obtained in experimental animals.     

Active Calcium and Strontium Transport in Human Erythrocyte Ghosts

Both calcium and strontium could be transported actively from erythrocytes if adenosine triphosphate, guanosine triphosphate, or inosine triphosphate were included in the hypotonic medium used to infuse calcium or strontium into the cells. Acetyl phosphate and pyrophosphate were not energy sources for the transport of either ion. Neither calcium nor strontium transport was accompanied by magnesium exchange, and the addition of Mg⁺⁺ to the reaction medium in a final concentration of 3.0 mmoles/liter did not promote the transport of either ion. In the absence of nucleotide triphosphates, the addition of 1.5 mmoles/liter of Sr⁺⁺ to the reaction solution did not bring about active calcium transport and similarly 1.5 mmoles/liter of Ca⁺⁺ did not bring about active strontium transport. The inclusion of 1.5 mmoles/liter of Ca⁺⁺ or Sr⁺⁺ in the reaction medium did not interfere with the transport of the other ion when the erythrocytes were infused with adenosine triphosphate.     

Comparison of the Elution and Absorption of Picornaviruses by Cotton and Calcium Alginate Wool Swabs

The recovery of picornaviruses by cotton and calcium alginate wool swabs was studied by use of prototype strains of poliovirus 1, echovirus 1, coxsackievirus A9, and rhinovirus 16/60. No significant differences in recovery of viruses by the two types of swabs could be demonstrated. It is suggested that use of cotton swabs in the virus laboratory be continued, since wool swabs may favor the recovery of undesirable bacterial contaminants. Adsorption of viruses by cotton and wool swabs was similar from virus-buffer mixtures at pH 4.0, 7.0, and 8.0 at 24 and 37 C. Elution of virus from cotton and wool swabs was also studied. There was no significant difference in the amount of virus eluted at pH 5.5, 7.1, or 8.4.     

具有佐剂效果的海藻酸钙纳米胶囊制备

利用海藻酸多糖酸沉淀性质并结合乳化技术,本研究开发了一种酸沉淀诱导相变制备海藻酸钙纳米胶囊的新颖方法,并通过改变海藻酸钠溶液和表面活性剂浓度获得了最小平均水动力学直径在300 nm以下的球形凝胶颗粒,粒径分布均一,表面呈负电性。细胞培养实验结果表明,该海藻酸钙纳米胶囊对人外周血来源未成熟树突状细胞的成熟有与肿瘤坏死因子?（TNF-?）和细菌脂多糖（LPS）相当效力的刺激作用。蛋白质分子可通过共价偶联方式负载。该海藻酸钙纳米胶囊在新型疫苗设计、细胞治疗和靶向给药等方面具有重要的应用潜力。     

The Effect of Calcium on the Uptake and Distribution of Sodium in Excised Barley Roots

The total uptake and relative distribution of Na⁺ along the root was investigated in excised barley roots (Hordeum vulgare L. cv. Union) of 6-day-old plants cultured on 0.25 mM CaSO₄. One technique involved cutting the roots at harvest time after different uptake periods into different segments each 2 cm long. These segments were ashed and sodium was measured by flame photometry. For each experiment two treatments were done, one containing calcium in the uptake solution and one without calcium. A second technique involved the measurement of sodium transport, using labelled ²²Na⁺ solution. Although no significant differences could be found between the calcium containing and the calciumless treatments at 24 h, there were clearcut differences for the first 6 to 8 h. The effect of calcium on the first stages of the sodium uptake was a large accumulation of sodium in the part close to the apex with a translocation close to nil; whereas the sodium taken up in the absence of calcium did not accumulate in such large amounts in the apex region but was immediately transported basipetally.     

Effect of Sodium Alginate on Staphylococcus aureus During Mild Heating and Freezing

The effects of sodium alginate on Staphyiococcus aureus 196 exposed to mild heating or to freezing at -21 C were studied. The addition of sodium alginate to a diluent appeared to confer some protection of viable cells during mild heating. The effect of the presence of sodium alginate in the suspending media during freezing was less clear. There was a slight trend, not statistically significant, for greater reduction in numbers of viable cells at the low temperature when 4% alginate was present in phosphate buffer. Results indicated that the value of sodium alginate in controlling this food-poisoning microorganism in frozen food is questionable.     

The Effect of Oxalate and Ethylenediaminetetraacetic acid on the Absorption of Calcium into Lemna

Oxalate supplied to Lemna gibba L. in sterile culture was readily absorbed, stimulating growth and increasing the uptake of calcium when this element was present in the nutrient medium; in the absence of calcium, deficiency symptoms rapidly appeared. EDTA at low concentrations stimulated growth, but concentrations equivalent to those of calcium reduced the uptake of both calcium and oxalate; developing daughter fronds were chlorotic and cells from these tissues appeared to be calcium deficient.     

Effect of Sodium Alginate Addition on Physical Properties of Rennet Milk Gels

Effect of addition of sodium alginate (alginate) to milk on the storage modulus (G′), water holding capacity (WHC) and hardness of rennet gels was evaluated as a function of alginate (0–0.25 g/100 g) and fat (0.5–3.0 g/100 g) concentrations. There was a significant effect of alginate addition on ionic calcium in milk and whey (Ca²⁺), and particle size distribution in alginate added milk. Results showed a positive correlation of alginate with WHC; negative correlation of alginate and positive correlation of fat with G′; and negative correlation of interaction of fat and alginate with gel hardness of rennet gels. Hence, the rennet gels with lower fat content and higher added alginate tended to be softer due to the high water holding capacity of the alginate particles.     

纳米珍珠粉对大鼠钙吸收利用的影响

目的研究纳米珍珠粉对大鼠钙吸收利用的影响,并比较纳米和微米珍珠粉对大鼠生长发育和骨钙水平作用的差异。方法出生21d断乳SD大鼠100只,喂养低钙饲料2周。随机分为5组,雌雄各半,Ⅰ～Ⅱ组分别为微米珍珠粉低、高剂量组,喂饲饲料为低钙饲料混合不同剂量的微米珍珠粉;Ⅲ～Ⅳ分别为纳米珍珠粉低、高剂量组,喂饲饲料为低钙饲料混合不同剂量的纳米珍珠粉;Ⅴ组为低钙对照组,喂饲低钙饲料;另取10只SD大鼠为实验本底组(即Ⅵ组),Ⅵ组于实验开始前处死。实验期为4周。结果2个不同剂量的纳米珍珠粉组的大鼠体重、股骨干重及长度、钙吸收率、钙存留率均高于2个相应剂量的微米珍珠粉组,且差异有显著性(P<0.05)。结论纳米珍珠粉能够被大鼠很好地吸收利用,具有增加骨钙含量的功能,在钙吸收利用作用方面明显优于微米珍珠粉。     

Effect of Chlorothiazide on Cesium-137 Excretion in Human Subjects

The therapeutic value of the diuretic, chlorothiazide (Diuril), in reducing the body burden of cesium-137 in human subjects was investigated. Two subjects were given chlorothiazide, 2 g./day, following a single oral intake of cesium-137. The urinary excretion and the per cent retention of cesium-137 were compared with similar data obtained from two control subjects. Although chlorothiazide produced a marked potassium diuresis, it had no significant effect in reducing the body burden of cesium.Analysis was made of the rate of turnover of cesium and potassium in the two control subjects, who were followed up for 320 days. The biological half-lives, T_b, of K were 42 and 41 days. In both subjects a small fraction of the cesium-137 was rapidly excreted. The remainder (88% and 83% in the two cases) was excreted at a slower constant rate. The concentrations further decreased to 44% and 41.5% in 90 and 155 days, respectively.     

The Effect of Hydrosatic Pressure Gradients on the Movement of Sodium and Calcium across the Root Cortex

The hydrostatic pressure gradient across the root cortex inducedby transpiration was simulated by raising the pressure on themedium surrounding the roots of detopped tomato (Lycopersicumesculentum) and castoroil plants (Ricinus communis).Applyinga pressure of 2 atm. resulted in a doubling of the sodium fluxfrom medium to xylern (table I). This flux depended on a maintainedsuply of Na in the medium (fig.1) indicating that there wasa small but readily available storage and exchange capacityfor Na in the root tissues. In the presence of metabolic inhaibitorsthe Na flux was considerablyu reduced and equalled the fluxof mannitol (talble II) believed to be a passive mass flow.The Na flux under a pressure gradient appeared therefore tobe metabollism-facilitated. Metabolic inhibition after the rootshad been allowed to take up Na led to a large flux of sodiuminto the xylem (Fig.2). This was considered to come from a largeunavailable store in the roots. Metabolism-facilitated processes also appeared to predominatein the flux of calcium to the xylem of Ricinus, buit not inthe flux through tomato roots. The location of the centripetal metabolism-facilitated transferand the available and unavailable stores is discussed in relationto the effects of pressure gradients.