Perchlorate inhibition of iodide uptake in normal and iodine-deficient rats

Perchlorate-induced inhibition of thyroidal iodide uptake was measured in normal and iodine-deficient female Sprague-Dawley rats. Rats that were made iodine-deficient by long-term restriction of iodine in the diet absorbed a gavage dose of 131I to the thyroid in proportionally greater amounts than rats fed a normal diet. Furthermore, the iodine-deficient rats maintained their high rates of absorption even when challenged by levels of perchlorate in their drinking water sufficient to produce pronounced inhibition of 131I uptake in rats fed a normal diet. Every dose of perchlorate used in this study (1.1, 5.6, and 28 mg/L) produced significant inhibition of iodide uptake in normally fed rats, but only the highest level of perchlorate (28 mg/L) significantly inhibited thyroidal uptake of 131I in the iodine-deficient rats. Taken together, these results demonstrate that iodide-deficient animals exhibit increased resistance to the inhibition of iodine absorption resulting from perchlorate exposure.     

Effect of a sodium-poor diet on lithium clearance at different dietary potassium contents in rats

In rats on a diet with a sodium content of 300 mmol/kg, lithium is reabsorbed exclusively in the proximal tubules, and lithium clearance (CLi) equals the proximal tubular fluid output (Vprox). In rats on a sodium-poor diet (5 mmol/kg), lithium is also reabsorbed in the distal nephron and CLi is therefore lower than Vprox. The present paper examines the reduction of CLi in response to a low sodium diet in Brattleboro rats with hereditary diabetes insipidus maintained on different dietary potassium contents. CLi was reduced by about 60 microliter/min./100 g body weight in response to a low sodium diet. The absolute reduction in CLi caused by low sodium diet was unaffected by an increase of CLi provoked by administration of potassium with the diet, and it was unaffected by variations of CLi which occurred spontaneously within each group. CLi was accordingly reduced by a constant absolute value rather than by a constant percentage. The reduction of CLi (60 microliter/min./100 g body weight) was equal to CLi in the group given a potassium-poor diet with a normal sodium content. In the low-sodium and low-potassium group CLi was reduced to almost zero. Using CLi as a measure of Vprox in the rats on a 300 mmol/kg sodium diet it is concluded that the absolute reduction of CLi in response to a sodium-poor diet is 1) unaffected by increase of Vprox produced by administration of potassium with the food,2) unaffected by spontaneous variations of Vprox, and 3) equal to Vprox in rats given a potassium-poor diet.     

Prolonged diuretic administration and myocardial tolerance to ischaemia

Hearts from rats, which received high doses of furosemide alone or the same doses of furosemide plus amiloride in a diet with low magnesium content for 4 weeks, were isolated and perfused in the Langendorff mode. After 15 min. of normoxic control perfusion no differences were found between the two groups of hearts with respect to cardiac physiology. After 20 min. of subtotal, global ischaemia and 15 min. of reperfusion the furosemide plus amiloride hearts showed a significantly higher recovery of function (judged by pressure rate product and coronary flow rate) than furosemide hearts. However, the myocardial content of adenosine triphosphate, creatine phosphate, and electrolytes at the end of the experiment exhibited no difference between the two groups. In separate experiments it was found that the addition of amiloride to the furosemide regimen significantly raised and almost normalized the values of plasma magnesium and potassium. Myocardial calcium was lower, whereas the magnesium and potassium content in the hearts was not different from the furosemide group. It is concluded that the administration of amiloride to rats provided high doses of furosemide and marginal magnesium supplies afforded some protection upon the ischaemic heart.     

Growth and sporulation characteristics of Bacillus megaterium under different conditions of nutrient limitation

The quantitative nutritional requirements to achieve specific cell densities have been studied for B. megaterium. Growth of batch cultures was separately limited by depletion of glucose, ammonium, sulphate, potassium, phosphate, manganese and magnesium. Maximum population density (E₄₂₀) for graded concentrations of each limiting nutrient was plotted against nutrient concentration and a linear plot was obtained below a critical concentration. Under conditions of magnesium depletion, two phases of growth occurred separated by a plateau. Proposals are made for the use of these cultures in drug resistance studies. Sporulation occurred in all cultures except those limited by potassium, manganese or magnesium. Spores were produced in magnesium-limited cultures provided that glucose was simultaneously depleted. Spores produced under different conditions of nutrient depletion varied in germination characteristics, heat resistance and spore volume.     

EFFECT OF MAGNESIUM DEPLETION AND POTASSIUM DEPLETION AND CHLOROTHIAZIDE ON INTRACELLULAR pH IN THE RAT, STUDIED BY 31P NMR

1. Both dietary magnesium depletion and potassium depletion (confirmed by tissue analysis) were induced in rats which were then compared with rats treated with chlorothiazide (250 mg/kg diet) and rats on a control synthetic diet. 2. Brain and muscle intracellular pH was measured by using a surface coil and [31P]-NMR to measure the chemical shift of inorganic phosphate. pH was also measured in isolated perfused hearts from control and magnesium-deficient rats. Intracellular magnesium status was assessed by measuring the chemical shift of beta-ATP in brain. 3. There was no evidence for magnesium deficiency in the chlorothiazide-treated rats on tissue analysis or on chemical shift of beta-ATP in brain. Both magnesium and potassium deficiency, but not chlorothiazide treatment, were associated with an extracellular alkalosis. 4. Magnesium deficiency led to an intracellular alkalosis in brain, muscle and heart. Chlorothiazide treatment led to an alkalosis in brain. Potassium deficiency was associated with a normal intracellular pH in brain and muscle. 5. Magnesium depletion and chlorothiazide treatment produce intracellular alkalosis by unknown mechanism(s).     

Potassium prevention of lithium-induced loss of water and sodium in rats

Lithium was administered to rats with the food in amounts leading to serum lithium concentrations of 0.6–0.8 mmol/liter. The animals had free access to water and 0.46 m NaCl solution. Some of the rats were given a diet to which 500 mmol/kg of either potassium chloride or potassium phosphate had been added, while other rats received food without extra potassium. In the course of 3 weeks the water and sodium intakes increased in all groups, but they increased significantly less in the rats given potassium than in those given no extra potassium. During 6 hr of fluid deprivation the rats given extra potassium showed significantly less urine production, weight loss, and increase in serum sodium concentration. When access to NaCl solution was withdrawn the animals given extra potassium were almost unaffected whereas within 14 days the animals not given extra potassium developed lithium intoxication characterized by weight loss, decreased intake of water and food, lowered serum sodium concentration, and increased serum lithium concentration; two of the seven rats in this group died. In none of the experiments was there any difference between rats given potassium chloride and rats given potassium phosphate. The data indicate that a high potassium content in the food prevents lithium-induced renal inability to retain water and sodium.     

The effects of 2-thiophenecarboxylic acid on serum ionic calcium and magnesium levels in rats

1. Administration of 2-thiophenecarboxylic acid to rats maintained on a low calcium diet resulted in a significant depression in the serum levels of total and ionized calcium and inorganic phosphate. 2. The serum magnesium levels were not altered by the drug.     

Experimental studies on the intestinal uptake of organic and inorganic magnesium and potassium compounds given alone or simultaneously

The peroral administration of magnesium and potassium compounds in effective doses (ED50) to rats yielded the following results: 1. Magnesium or potassium given as chlorides are significantly better absorbed than the corresponding aspartates. 2. In the presence of aspartate in higher concentrations the absorption of both magnesium and potassium is inhibited to a certain degree. 3. Increasing amounts of chloride cannot abolish the inhibitory effect of aspartate on potassium absorption, in contrast magnesium, which, in the presence of aspartate is better taken up when chloride is provided. 4. High concentrations of magnesium may perhaps impede the uptake of potassium to a small degree but not vice versa. 5. Magnesium losses from the body--induced by treatment with 9-alpha-fluorocortisol-acetate--can be effectively substituted by peroral administration of chloride-containing magnesium compounds over a reasonable time. The simultaneously occurring loss of potassium cannot be corrected correspondingly by potassium supplements.     

Improvement of cardiovascular effects of metoprolol by replacement of common salt with a potassium- and magnesium-enriched salt alternative.

1. The influence of sodium chloride (NaCl)-enrichment of the diet (6% of the dry weight) and that of a novel sodium-reduced, potassium-, magnesium-, and L-lysine-enriched salt alternative on the cardiovascular effects of the beta 1-adrenoceptor blocking drug, metoprolol, was studied in stroke-prone spontaneously hypertensive rats. 2. Increased dietary sodium chloride intake produced a marked rise in blood pressure and induced left ventricular and renal hypertrophy. By contrast, the salt alternative did not increase blood pressure and caused remarkably less cardiac and renal hypertrophy than did sodium chloride. 3. Metoprolol treatment at a daily dose of 250 mg kg-1 lowered blood pressure and decreased left ventricular hypertrophy index during the control diet. Sodium chloride-enrichment blocked the antihypertensive effect of metoprolol, while a partial protective effect on left ventricular and renal hypertrophy persisted. In the presence of the salt alternative-enrichment both at the level of 6% and 10.5% (corresponding to a NaCl level of 6%), metoprolol was fully able to exert its beneficial cardiovascular and renal effects. 4. Both salt supplementations, irrespective of metoprolol treatment, induced a 3 to 4 fold increase in the urinary excretion of calcium. There was a linear correlation between the urinary excretions of sodium and calcium. The urinary excretion of magnesium rose by 90% and that of potassium by 110% in the salt alternative group. 6. Our findings suggest that replacement of common salt by a potassium-, and magnesium-enriched salt alternative in the diet produces beneficial cardiovascular effects and improves the antihypertensive efficacy of metoprolol in stroke-prone spontaneously hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Column extraction of chlorpyrifos from contaminated fish.

A method for measuring chlorpyrifos in fish, which combines extraction, filtration, and cleanup in one step, is described. Minced fish samples were mixed with potassium dihydrogen phosphate and disodium hydrogen phosphate, ground with anhydrous sodium sulfate, and eluted from a prepacked chromatographic column containing silica gel. The endogenous coextractives were retained by the column while chlorpyrifos was quantitatively eluted with 40 mL of 5% ether in hexane. Recoveries averaged 86.8% for unexposed fish fortified with 2-12 ppm of chlorpyrifos. The method was applied to the analysis of fish from a lagoon contaminated with chlorpyrifos by a spray treatment of a wooden bridge for termites.     

矿物药大青盐中杂质元素的扫描电镜分析

目的通过对不同产地矿物药大青盐的扫描电镜分析研究,了解大青盐所含的杂质成分、杂质的含量及有害元素的组成。方法采用德国LEO1430VP环境扫描电子显微镜,配备INCA 200型X-射线能谱仪来分析大青盐。结果与结论通过扫描电镜能谱分析结果,大青盐主要含有氧、钠、镁、铝、硅、氯、钾、钙、铁、硫等元素,且不同盐中所含杂质差异较大;与大青盐伴生的化合物可能为钾、钙、镁、硅的氧化物,或含氧酸盐;也可能为钾、钙、镁的氯化物;同时也可能伴有钠的含氧酸盐。     

Effect of oral iron supplementation on oxidative stress and colonic inflammation in rats with induced colitis

BACKGROUND: Iron supplementation may increase disease activity in ulcerative colitis, possibly through the production of reactive oxygen species from the Fenton reaction. AIM: To assess the effects of two doses of oral iron on intestinal inflammation and oxidative stress in experimental colitis. METHODS: Colitis was induced in rats by giving 5% dextran sulphate sodium in drinking water for 7 days. First, using a 2 x 2 factorial design, rats with or without dextran sulphate sodium received the regular diet or a diet containing iron 3%/kg diet. Second, rats with dextran sulphate sodium-induced colitis were supplemented with iron 0.3%/kg diet and compared with rats on dextran sulphate sodium and regular diet. The body weight change, histological scores, colon length, rectal bleeding, plasma and colonic lipid peroxides, colonic glutathione peroxidase and plasma vitamin E and C were measured. Faecal analysis for haem and total, free and ethylenediaminetetra-acetic acid-chelatable iron was also performed. RESULTS: Iron 3% and iron 0.3% increased the activity of dextran sulphate sodium-induced colitis, as demonstrated by higher histological scores, heavier rectal bleeding and further shortening of the colon. This was associated with increased lipid peroxidation and decreased antioxidant vitamins. Faecal iron available to the Fenton reaction was increased in a dose-dependent manner. CONCLUSIONS: Iron supplementation taken orally enhanced the activity of dextran sulphate sodium-induced colitis and is associated with an increase in oxidative stress.     

Nitric oxide as a mediator of the laxative action of magnesium sulphate.

1. Magnesium sulphate was studied for its effects on diarrhoea, fluid secretion, gastrointestinal transit and nitric oxide (NO) synthase activity in rats. 2. At a dose of 2 g kg-1 orally magnesium sulphate produced diarrhoea that was delayed in onset and intensity in a dose-related manner by the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME). This was prevented by the NO precursor, L-arginine and the NO donating compound, isosorbide-5-mononitrate (IMN). 3. Nitric oxide synthase activity was stimulated in gut tissue from rats given magnesium sulphate and this was inhibited by L-NAME. Dexamethasone (1 mg kg-1, i.p.), an inhibitor of inducible NO synthase, had no effect on magnesium sulphate-induced diarrhoea. 4. Magnesium sulphate stimulated fluid and electrolyte accumulation in the intestinal lumen; these effects were prevented by L-NAME but not D-NAME. 5. Gastrointestinal transit of a non-absorbable marker (charcoal suspension) was increased by oral magnesium sulphate from a mean value of 54.1% to 72.9% (P < 0.01), and this was prevented by pretreatment with L-NAME. 6. The results demonstrate that oral magnesium sulphate produces diarrhoea in rats by increasing the accumulation of fluid in the intestinal lumen and enhancing flow from the proximal to distal intestine. The mechanism involves release of NO, probably through stimulation of the constitutive form of NO synthase. Whether or not the effects of magnesium sulphate are due to an osmotic action or an intrinsic effect of the magnesium or sulphate ions cannot be determined from these experiments.     

The effect of media composition on the thermal resistance of Bacillus stearothermophilus

Spores of Bacillus stearothermophilus ATCC 7953 were developed at 62 degrees C on 32 media composed of various amounts of 11 components: D-glucose, L-glutamic acid, yeast extract, peptone, sodium chloride, magnesium sulfate, ammonium phosphate, potassium phosphate, calcium chloride, ferrous sulfate and manganese sulfate. Statistical models were used and demonstrated a strong interaction of yeast/peptone/ammonium phosphate, contributing positively to the best sporulation yield (6-7 log10 spores). The most influential medium components on the thermal resistance (at 121 degrees C) of spores in suspension (calcium acetate, pH 9.7) were yeast extract (positively) and potassium phosphate (negatively), both creating the positive interaction, for spores from a 6-day incubation period. However, the strong negative effect of sodium chloride decreased the D-value from 1.81 min to 0.57 min upon increasing the incubation period (62 degrees C) from 3 days to 6 days. The D-glucose and peptone exhibited greater effects than the yeast extract and potassium phosphate interaction on D-values for 3-day spores on strip, just as the highly joint-positive peptone/sodium chloride effect maintained the thermal resistance of 6-day spores on strips. The spores on strip system showed less stability than the spores in suspension. The most stable spore system confirmed D-values at 121 degrees C at a range between 1.5 min and 1.9 min, which were obtained by keeping sodium chloride and potassium phosphate at minimum concentrations and yeast extract and peptone at maximum concentrations, regardless of the 3- to 6-day sporulation.     

Hypolipidemic and antiatherogenesis effect of culinary-medicinal pink oyster mushroom, Pleurotus salmoneostramineus L. Vass. (higher Basidiomycetes), in hypercholesterolemic rats

The present study was conducted to investigate dietary supplementation of Pleurotus salmoneostramineus fruiting bodies on biochemical and histological effects in hyper- and normocholesterolemic rats. Six-week-old female Sprague-Dawley albino rats were divided into three groups of 10 rats each. Feeding of diet containing a 5% powder of the fruiting bodies of P. salmoneostramineus in hypercholesterolemic rats reduced plasma total cholesterol, triglyceride, low-density lipoprotein, total lipid, phospholipids, and LDL/HDL ratio by 22.55, 51.38, 69.23, 29.67, 16.61, and 65.31%, respectively. The mushroom also significantly reduced body weight in hypercholesterolemic rats. Moreover, it had no adverse effects on plasma albumin, total bilirubin, direct bilirubin, creatinine, blood urea nitrogen, uric acid, glucose, total protein, calcium, sodium, potassium, chloride, inorganic phosphate, magnesium, and enzyme profiles. Feeding mushroom increased total lipid and cholesterol excretion in feces. The plasma lipoprotein fraction, separated by agarose gel electrophoresis, indicated that P. salmoneostramineus significantly reduced plasma β and pre-β-lipoprotein, while it increased α-lipoprotein. A histological study of liver tissues by conventional hematoxylin-eosin and oil red O staining showed normal in mushroom feed hypercholesterolemic rat. This study suggests that the P. salmoneostramineus diet supplement provided health benefits by acting on the atherogenic lipid profile in hypercholesterolemic rats.     

注射用头孢地嗪钠与注射用甲硝唑磷酸二钠配伍稳定性考察

目的:考察注射用头孢地嗪钠与注射用甲硝唑磷酸二钠分别在0.9%氯化钠注射液和5%葡萄糖注射液中配伍的稳定性。方法:在室温(25±1)℃条件下,观察并测定6h内配伍液的外观和pH值变化,采用高效液相色谱法测定头孢地嗪钠与甲硝唑磷酸二钠的含量并考察有无新物质生成。结果:2药配伍后6h内外观、pH、含量均无明显变化。结论:注射用头孢地嗪钠与注射用甲硝唑磷酸二钠在室温下6h内配伍稳定。     

对《中国药典》2015版附录无水磷酸氢二钠氯化物鉴别试验方法的改进

目的 ： 改进《中国药典》2015版药用辅料无水磷酸氢二钠氯化物鉴别试验方法,避免黄色悬浮物干扰比色结果。 方法：加入硝酸的量必须大于2.3mL或无水磷酸氢二钠称样量不能超过3.25g,避免滴加硝酸银溶液时与磷酸根反应生成黄色的磷酸银而干扰鉴别试验现象的观察。结果：加大硝酸的量或减少称样量,可以有效防止磷酸氢根电离和磷酸银的形成。结论：本方法可以避免比色鉴别试验出现黄色悬浮物结果。     

The effects of high dietary levels of sodium saccharin on mineral and water balance and related parameters in rats

The effects of sodium saccharin (NaS) treatment on mineral and water balance and a number of related parameters were studied over a 10-day period in 7-month-old Charles River CD rats. Eight groups of 10 male and 10 female rats were studied. In four of the groups the rats were the F1 offspring of rats that had been exposed to NaS at 1, 3, 5 or 7.5% in the diet and the offspring were treated with the same dietary levels of NaS as their parents. Prior treatment in two other groups was modified in order to evaluate the role of in utero exposure to NaS on the study parameters: rats in one group were only exposed in utero via dams fed diets containing 5% NaS while treatment in the other group did not include in utero exposure, but was started at birth via dams fed diets containing NaS and continued at a dietary concentration of 5% NaS. Second-generation rats in another group were fed diets containing 5% sodium hippurate (NaH), a compound with a number of physical and chemical properties similar to those of NaS; this group was included in order to evaluate the specificity of NaS and/or the effect of sodium on the study parameters. A group of untreated rats served as controls. Treatment-related effects were observed in most study parameters. In addition, a number of differences between male and female rats in baseline values and/or in response to NaS administration were observed. With increasing dietary levels of NaS body weights decreased, but there were increases in water consumption, faecal water content, and caecal weights. NaS treatment resulted in increased urine volume and decreased urine osmolality, changes in urine mineral concentrations (increased sodium, decreased potassium and zinc) and increases in fresh and dry bladder weights, bladder-tissue hydration, and mineral concentrations (sodium, potassium, magnesium and zinc) in bladder tissue. The parameters in which clear sex-related differences in baseline values were observed were body weight, food and water consumption, urine volume, urine osmolality, fresh bladder mass, bladder-tissue hydration and the concentrations of sodium, potassium, magnesium and zinc in the bladder tissue. With the exception of urine osmolality, the values were higher in females. Differences between males and females in response to treatment were observed for NaS consumption (increased in females), caecal weight (increased in females), NaS concentration in the urine (increased in males), and the concentration of sodium, potassium, magnesium and zinc in the bladder tissue (increased in males).(ABSTRACT TRUNCATED AT 400 WORDS)     

Effect of heparin and hypobaric hypoxia on the blood electrolyte composition, ATPase activity and the membrane charge of erythrocytes

The effects of hypoxia (an "altitude" of 6000 m) and heparin on contents of ions of sodium, potassium, calcium, and magnesium in the plasma and erythrocytes, on ATPase activity and erythrocyte membrane charge in albino rats were studied. Heparin was shown to decrease levels of ions of sodium, potassium, in the plasma and erythrocytes, to increase the negative charge of erythrocytes and membrane permeability for potassium ions. Changes in concentrations of sodium, potassium, calcium and magnesium ions after keeping the rats in a barochamber are more marked on the 2nd day than on the 4th day. Na+, K+-ATPase activity of erythrocyte ghosts first decreased, but on the 4th day increased. Heparin action tended to compensate for changes in contents of the studied ions, ATPase activity and erythrocyte membrane changes as well as changes in gradients of potassium, calcium and magnesium ions concentrations in the erythrocyte-plasma system caused by hypobaric hypoxia.     

CHANGE IN BLOOD PRESSURE IN RELATION TO CHANGE IN NUTRIENTS EFFECTED BY MANIPULATION OF DIETARY SODIUM AND POTASSIUM

1. As part of a study investigating the effect of dietary alterations of sodium and potassium intake on blood pressure, the changes in nutrients that occurred with dietary intervention were determined. 2. Mild hypertensive subjects were randomized to one of four dietary intervention groups: control; high potassium; low sodium; low sodium, high potassium. The changes in nutrients in each diet group were assessed by dietary history and five repeat 24 h dietary recalls. Assessment was validated by measurement of urinary nitrogen excretion and urinary electrolytes. 3. The three dietary intervention groups experienced a fall in blood pressure (systolic: 4.4 +/- 1.0 mmHg, P less than 0.005; diastolic: 3.3 +/- 0.7 mmHg, P less than 0.001), greater than that observed in the control group. 4. The only significant dietary change across all diet groups was a reduction in the dietary sodium/potassium ratio, which was significantly less than that of the control group. The only other nutrient to differ from the control in all groups was fat intake, which was reduced. 5. In the control group there was a small but significant decrease in energy, fibre, protein, carbohydrate, potassium and magnesium intake. In the high potassium group there was a significant increase in fibre, carbohydrate, potassium, magnesium, and a decrease in calcium intake. In the low sodium group there was a decrease in energy intake with a subsequent reduction in all nutrients except alcohol. In the low sodium, high potassium group there was a significant reduction in dietary sodium and protein and an increase in fibre, carbohydrate, potassium and magnesium. 6. The reduction of the dietary sodium/potassium ratio correlated with a reduction in the urinary sodium/potassium ratio. This was the best predictor for change in diastolic pressure in all groups, suggesting that reduction in the sodium/potassium ratio contributed to the fall in blood pressure. 7. Reduction of sodium intake and increase in potassium intake by dietary means caused a reduction in blood pressure which does not appear to be due to alteration of other measured dietary constituents.