Total Magnesium Concentrations Research Articles

Vertical distribution, nutrient concentration and seasonal changes of fine root mass in a semi-deciduous tropical dry forest and in two adjacent pastures in the Western Llanos of Venezuela

With the objective to contribute to a better understanding of ecological consequences of deforestation on the below-ground system in the Western Llanos of Venezuela, we evaluated the vertical distribution, nutrient concentration and seasonal changes of total fine root mass (FRM) (<2 mm diameter) in a semi-deciduous tropical dry forest and in 2 adjacent pastures of Cynodon nlemfuensis: a young pasture (YP, 5 years old) and an old pasture (OP, 18 years old) in the Obispo municipality, Barinas State. This evaluation included measurements at the end of the rainy season, during the dry season and during the subsequent early rainy season in 2005/2006. Highest FRM was recorded during the dry season, which probably indicates a plant water-stress response mechanism. The highest proportion (63‒88%) of FRM was concentrated in the 10–20 cm soil layer at all studied sites, probably due to a higher nutrient and moisture content at that depth. Non-significant differences (P>0.05) were observed in the total concentrations of organic carbon, nitrogen, phosphorus, calcium and magnesium in the FRM in soils supporting forest, OP and YP at the evaluated depths. Non-significant changes in the total FRM and nutrient concentrations were observed between the sampling periods and the 3 study sites. YP soils showed a slight increase in FRM that could be associated with the root growth of secondary vegetation, which is considered a weed and is periodically removed. Our results suggest that the land use change from tropical forest to pastures has not significantly affected the mass of fine roots and their carbon and nutrient concentrations. Further studies are needed to determine if these findings apply to other ecosystems.

CARACTERÍSTICAS FÍSICAS, QUÍMICAS E FÍSICO-QUÍMICAS DE CALCÁRIO EXTRAIDO DO SULDOESTE DA REGIÃO AMAZÔNICA

O presente trabalho tem por objetivo, analisar a concentração de cálcio, magnésio, Poder de Neutralização, Reatividade e Poder Relativo de Neutralização Total em calcário da região Norte. Foram determinados os teores totais de óxidos de cálcio (CaO) e magnésio (MgO) por volumetria utilizando o EDTA (ácido etilenodiaminotetracético) como agente complexante, solução tampão em pH = 10, e como indicador complexométrico, o corante orgânico Negro de eriocromo T. As análises foram realizadas em dez amostras de calcários, em que cada amostra corresponde a jazidas distintas. As amostras encontram-se dentro dos parâmetros que as classificam como calcário. Na classificação pelo teor de MgO, constatou-se que, das dez amostras analisadas, todas podem ser classificadas como calcário dolomítico, além de apresentar as quantidades mínimas de PRNT admitidas pela legislação.

The impacts of the single-use of different lime materials on the pond bottom soil with acid sulfate content

The strong acidity of water and soil in areas containing sulfate is the issue in aquaculture. This research aimed to investigate the influence of each liming material with different dosages to minimise the acidity effects in soil with acid sulfate content and to enhance water alkalinity. Dolomite (Ca Mg(CO3)2); (DA)50, (DB)10, and (DC) 5 ton/Ha), hydrated lime (Ca(OH)2); (HA) 2300, (HB) 1500, and (HC) 1300 Kg/Ha, as well as burnt lime (CaO); (OA) 260, (OB) 210, and (OC) 150 Kg/Ha were applied. Results indicated that each liming material affected the increase of pH in the sediment and water, alkalinity, as well as the decomposition of organic carbon. The highest dosage used in dolomite (DA), hydrated lime (HA), and burnt lime (OA) resulted in the highest pH level for soil and water, as well as alkalinity. The lowest amount of organic carbon was also recorded. Further analysis showed a high concentration of total calcium and magnesium and a decrease of acid-forming cations. An enormous amount of dolomite was needed, unlike burnt lime and hydrated lime treatments, to achieve the desired alkalinity and pH for both soil and water. Consequently, higher expenditure will probably be incurred in the extensive use of dolomite. Nevertheless, based on the results of soil and water properties, the application of hydrated lime (HA) tend to be more reliable in terms of effectiveness to minimise the problem in acid sulfate area.

Evaluation of the influence of cultivation on the total magnesium concentration and infusion extractability in commercial arabica coffee

Coffee is considered an important source of organic nutrients and minerals, and these resources are strongly affected by agricultural management. Among the minerals, the element Mg is important, which is essential for both plants and humans. In this work, the effects of agricultural management on the absorption and storage of Mg by commercial, ground, roasted Arabica coffee were investigated. For this purpose, some Mg and P fractions were evaluated. It was observed that Mg stored in the grain was concentrated in the inorganic fraction, with an average extraction of 102% and in conventional samples and 119% in organic samples. These results suggest that in these samples Mg is probably largely presented as different inorganic salts. Phytate and organic acid salts are two possibilities discussed in this work that could explain this hypothesis. This can be corroborated by the extraction of Mg in the infusion of hot water.

The effect of hemodialysis on serum magnesium concentration in hemodialysis patients.

In recent years, the concentration of magnesium in dialysis patients has drawn an increasing amount of attention. Both hemodialysis and peritoneal dialysis may affect magnesium metabolism, but studies in this area are very limited. This study aimed to investigate the serum magnesium concentrations in hemodialysis patients and examine the factors related to the serum magnesium concentration, and to explore the effect of hemodialysis with conventional hemodialysis solution (magnesium ion concentration 0.5 mmol/L) on blood magnesium concentration. In this single-center, retrospective study, linear regression models were established to explore the factors related to serum magnesium concentration in hemodialysis patients. Serum magnesium concentration was also compared before and after hemodialysis treatment. The data of 148 hemodialysis patients were collected and analyzed. The mean value of pre-hemodialysis total serum magnesium concentration was 1.11±0.14 mmol/L. The prevalence of hypermagnesemia was 73.65%, and 2 patients had hypomagnesemia (1.35%). Data analysis indicated that total platelet count, serum phosphorus level, serum creatinine, plasma albumin, and total serum cholesterol level were significantly related to serum magnesium concentration. After hemodialysis treatment, the serum magnesium concentration was significantly lower when conventional hemodialysis was used. After hemodialysis, the average decrease in the serum magnesium concentration was 0.14 mmol/L. Most patients who received hemodialysis had mild hypermagnesemia when routine dialysate was supplied. Serum magnesium concentration is related to patients' nutritional status. Hemodialysis treatment can decrease the total serum magnesium concentration.

Circulating Ionized Magnesium as a Measure of Supplement Bioavailability: Results from a Pilot Study for Randomized Clinical Trial.

Oral supplementation may improve the dietary intake of magnesium, which has been identified as a shortfall nutrient. We conducted a pilot study to evaluate appropriate methods for assessing responses to the ingestion of oral magnesium supplements, including ionized magnesium in whole blood (iMg2+) concentration, serum total magnesium concentration, and total urinary magnesium content. In a single-blinded crossover study, 17 healthy adults were randomly assigned to consume 300 mg of magnesium from MgCl2 (ReMag®, a picosized magnesium formulation) or placebo, while having a low-magnesium breakfast. Blood and urine samples were obtained for the measurement of iMg2+, serum total magnesium, and total urine magnesium, during 24 h following the magnesium supplement or placebo dosing. Bioavailability was assessed using area-under-the-curve (AUC) as well as maximum (Cmax) and time-to-maximum (Tmax) concentration. Depending on normality, data were expressed as the mean ± standard deviation or median (range), and differences between responses to MgCl2 or placebo were measured using the paired t-test or Wilcoxon signed-rank test. Following MgCl2 administration versus placebo administration, we observed significantly greater increases in iMg2+ concentrations (AUC = 1.51 ± 0.96 vs. 0.84 ± 0.82 mg/dL•24h; Cmax = 1.38 ± 0.13 vs. 1.32 ± 0.07 mg/dL, respectively; both p < 0.05) but not in serum total magnesium (AUC = 27.00 [0, 172.93] vs. 14.55 [0, 91.18] mg/dL•24h; Cmax = 2.38 [1.97, 4.01] vs. 2.24 [1.98, 4.31] mg/dL) or in urinary magnesium (AUC = 201.74 ± 161.63 vs. 139.30 ± 92.84 mg•24h; Cmax = 26.12 [12.91, 88.63] vs. 24.38 [13.51, 81.51] mg/dL; p > 0.05). Whole blood iMg2+ may be a more sensitive measure of acute oral intake of magnesium compared to serum and urinary magnesium and may be preferred for assessing supplement bioavailability.

Investigation of the Magnesium Impurity in Silicon

The diffusion profiles of the concentration of electrically active and total concentrations of the magnesium impurity in silicon are measured. Diffusion is carried out by the sandwich method into FZ dislocation-free n-type silicon at the temperatures Tdiff = 1000 and 1100°C, and at a process duration from 0.5 to 22.5 h. The concentration profiles $${{N}_{{{\text{M}}{{{\text{g}}}_{i}}}}}$$(x) of the electrically active magnesium component are determined by the differential-conductivity method, and the total-concentration profiles Ntotal(x), by secondary-ion mass spectroscopy. It is established that the total concentration of magnesium in the samples is ~2 orders of magnitude higher than that of the electrically active component. It is also found that the diffusion coefficient $${{D}_{{{\text{M}}{{{\text{g}}}_{i}}}}}$$ of interstitial magnesium depends on the diffusion time and decreases with an increase in the duration of the process. Assumptions are made about the physical processes, which can lead to the formation of an electrically inactive component of magnesium impurity and to the dependence of the effective diffusion coefficient on time.

Influence of slope aspect on the macro- and micronutrients in Artemisia sacrorum on the Loess Plateau in China.

Slope aspect is an important topographic factor for a micro-ecosystem environment that may affect macro- and micronutrients in plants and soil. The south-, northwest-, and north-facing slopes were selected to investigate the influence of slope aspect on the concentrations, storage, and allocation of macro- and micronutrients in Artemisia sacrorum on the Loess Plateau in China. The concentrations of available manganese (Mn) in both rhizosphere and non-rhizosphere soils reached their maximum on the north-facing slope. The concentrations of available iron (Fe) in rhizosphere soil and available copper (Cu) in non-rhizosphere soil reached their maximum on the south-facing slope. Slope aspect significantly affected the total concentrations of potassium (K), calcium (Ca), magnesium (Mg), Cu, and Mn in rhizosphere and non-rhizosphere soils, and all of these elements reached their maximum on the northwest-facing slope. Slope aspect significantly influenced the concentrations of aboveground K, Ca, and Mg, sodium (Na), Mn, and belowground K in A. sacrorum, and the concentrations of aboveground K, Ca, Mg, and Na and belowground Mn, Na, Fe, Ca, and Mg in weed. Most elements in A. sacrorum and the weeds reached their maximum on the south-facing slope. Slope aspect significantly changed the aboveground-to-belowground concentration ratios of K, Ca, and Na in A. sacrorum and weed. Slope aspect significantly affected the storage of macro- and micronutrients in A. sacrorum and weed but not the storage in the plants of the entire plot. Slope aspect predominantly affected the storage allocation of macro- and micronutrients in A. sacrorum but not those in weed. Slope aspect is an important topographic factor that affects the macro- and micronutrients in plants and soil in micro-ecosystem environments.

Effects of Chitosan on the Uptake of Total Calcium, Magnesium and Sodium in Peach Seedlings

In this experiment, peach seedlings, as materials, were treated with various concentrations (0, 1, 2, 4 and 6 g/L) of chitosan. The content of total calcium, magnesium and sodium in roots, stems and leaves of peach seedlings were all measured. Overall, the chitosan treatments could increase the total calcium, magnesium and sodium content in roots and stems, especially at chitosan concentration of 2 g/L. In other words, spraying different concentrations chitosan solution could promote the accumulation of nutrient elements and the plants growth. However, the total calcium and sodium content in leaves of chitosan-treated seedlings were significantly lower than that in control seedlings. In soil, the water-soluble calcium content was higher and the water-soluble magnesium and sodium content were all the highest at 2 g/L chitosan concentration. Thus, to a certain extent, it’s good for spraying chitosan solution for the better growth and nutrient uptake of total calcium, magnesium and sodium in peach seedlings.

Hillock assisted p-type enhancement in N-polar GaN:Mg films grown by MOCVD

We report on the enhanced incorporation efficiency of magnesium dopants into facets of hexagonal hillock structures in N-polar GaN, studied by comparative analysis of GaN:Mg films grown by MOCVD on high and low hillock density GaN template layers. Total magnesium concentration in planar regions surrounding a hillock structure is comparable to that within hillock sidewall facets measured at 1.3 × 1019 cm−3 by atom probe tomography, and clustering of Mg atoms is seen in all regions of the film. Within individual hillock structures a decreased Mg cluster density is observed within hillock structures as opposed to the planar regions surrounding a hillock. Additionally, the Mg cluster radius is decreased within the hillock sidewall. The favorable incorporation of Mg is attributed to Mg dopants incorporating substitutionally for Ga during growth of semi-polar facets of the hillock structures. Enhanced p-type conductivity of GaN:Mg films grown on high hillock density template layers is verified by optical and electrical measurement.

Blood plasma chemistry in White Sea bearded seals across different age groups

Blood chemistry values are reported for the bearded seal species (Erignathus barbatus barbatus Erxleben, 1777) from the White Sea. 27 blood plasma indices are used to describe the state of the metabolism of proteins, carbohydrates, lipids, minerals (total protein, albumin, α-, β-, γ-globulins, urea, creatinine, uric acid, glucose, lactic acid, total lipids, triglycerides, cholesterol, calcium, phosphorus, sodium, potassium, magnesium, iron, copper, chlorides, aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transferase, creatine kinase, alkaline phosphatase, lactate dehydrogenase) in 3-, 5- and 10-year-old seals. The values of the studied parameters are similar to published data for bearded seal populations in other Arctic regions, as well as being in close agreement with indicators of other pinniped species of the same age. The plasma content of total protein, albumin, α-, β-, γ-globulins, urea, uric acid, total lipids, calcium, magnesium, sodium, and chlorides is invariable in animals of the studied ages. In common with other pinnipeds and land-based mammals, age-related changes in metabolic rates in the studied animal groups are most pronounced in the activity level of key metabolism enzymes. While aspartate aminotransferase, alanine aminotransferase and γ-glutamyl transferase activity is higher in adult seals than in immature animals, alkaline phosphatase, creatine kinase and lactate dehydrogenase activity is lower. Changes in biochemical parameters of bearded seal blood at the ages of 3, 5 and 10 years indicate a catabolic orientation in metabolism at all studied development stages. Although more research is needed to investigate the biological significance of a number of blood indices, the data presented in this study provide initial baseline blood chemistry parameters for use in assessing the condition of individual seals, as well as informing monitoring and management efforts for wild seal populations.

Magnesium in soils and plants of a sloping agrolandscape in the south-east of West Siberia

The aim of the study. To carry out a comparative assessment of the magnesium status in soils, situated on the various hypsometric levels of sloped agrolandscape and with different soil organic matter content by measuring total, mobile (exchangeable) and water-soluble magnesium in soils and to compare different analytical methods for determining magnesium in soils and plants. Location and time of the study. The study site was located in the Cis-Salair drained plain in the south-east of West Siberia (55˚02΄20˝N; 83˚50΄00˝E), administratively being within the boundaries of the Toguchin district of the Novosibirsk region, Russia. Altitude increments were marked on the slope positions of the investigated plot of 225 hectares in area and 4 km in length: the upper part of the slope BCI (280-310 m a.s.l. ), the midslope BCII (260-280 m) and BCIII (220-260 m), and the lower slope BCIV (190-220 m) (see figure 1). Soil and plant samples were collected in July 2013. Materials and methods. Prevailing soils were podzolized and leached chernozems, dark-gray and gray-forest soils according to the classification of soils of the USSR (1977), which correspond to clayey-illuvial eluvialed and dark-tongue agrochernozems, agro-dark gray soils and agro-gray soils to according of the Russian soil classification (2004, 2008), or Luvic Greyzemic Chernozems, Haplic Chernozems, Luvic Greyzemic Phaeozems, Luvic Retic Greyzemic Phaeozems by WRB Soil Classification (2014) (see table 1, figure 1). Individual soil samples (n=55) were taken with a drill from 0-30 cm layer (ploughed horizon) according to an irregular grid. The aboveground phytomass stock of oat-pea mixture (n=38) was collected using the hay cutting method on the ​​0.25 m2 area. The geographical coordinates of the soil and plant sampling sites were determined using the geopositioning system (GPS, Garmin eTrex Vista). The soil samples were analyzed for organic carbon content by dichromate digestion. Overall the studied soils were grouped according to soil organic matter (SOM) content into high-SOM (5-8%) and medium-SOM soils (3-5%). Total magnesium (Mgtot) was measured in dry powdered samples by atomic emission spectrometry; mobile (exchangeable) magnesium was measured by atomic absorption spectrometry using 1 M KCl, 1 M CH3COONH4, 0.1 M C4H4O5(NH4)2 and 0.5 M CH3COOH as extracting solutions. The same extracts were used to measure water-soluble magnesium atomic absorption spectrometry and capillary electrophoresis. The content of total magnesium in plants was determined by atomic absorption spectrometry using two methods of sample digestion, namely wet ashing in a mixture of sulfuric and perchloric acids and dry ashing followed by quantitative transfer of the digest with 1 M HCl. Magnesium content in soils and plants was presented per element and calculated on the air-dry mass basis. Statistical analyses (descriptive statistics, correlation analysis, calculation of student criterion and Mann-Whitney U-test) were performed using Microsoft Office Excel 2007 and Statistica v.6.1. Results. The average content of total magnesium in the slope soils varied from 0.79 to 0.88%. The proportion of mobile magnesium in its total content in soils averaged 3.3-6.0%, whereas that of water-soluble magnesium was 0.06-0.13%. In medium-SOM soils down along the slope the total magnesium content gradually decreased: agrochernozems → agro-dark gray soils → agro-gray soils (see table 2, figure 2). The similar pattern was revealed an earlier for the content of total phosphorus and total potassium in the slope soils. The average content of mobile magnesium in the high-SOM soils on the upper part of the slope (BCI) varied from 3.2 to 4.0 cmol(+)∙kg-1, depending on the extractant used. The medium-SOM soils (BCII-IV) contained 2.2 to 3.2 cmol(+)∙kg-1 of mobile magnesium. Atomic absorption spectrometry and capillary electrophoresis produced very close values water-soluble magnesium content in soils: on average, 0.06-0.08 and 0.04-0.09 cmol(+)∙kg-1, respectively. However, capillary electrophoresis proved to be more sensitive to the decreased content of water-soluble magnesium in the midslope medium-SOM soils. Magnesium content in aboveground phytomass of an oat-pea mixture, collected in the tillering phase of its cereal component, determined by dry ashing, averaged 0.21-0.26%, which corresponded to the optimal level of the element; estimated by wet ashing it was 1.3-1.6 times lower (see table 2). Conclusions. Under the conditions of the sloping agrolandscape of the Cis-Salair in the south-eastern part of West Siberia, high-SOM soils in the upper part of the slope are characterized by higher content of mobile magnesium as compared with the medium-SOM soils mid- and downslope. We believe that for assessing magnesium status of soils it is more expedient to use 1 M KCl or 1 M CH3COONH4 to determine mobile (exchangeable) magnesium. Moreover, these extractants can be used for simultaneous determination of other soil properties, i.e. exchangeable calcium and potassium content, pHsalt, etc.

Magnesium in soils and plants of a sloping agrolandscape in the south-east of West Siberia

The aim of the study. To carry out a comparative assessment of the magnesium status in soils, situated on the various hypsometric levels of sloped agrolandscape and with different soil organic matter content by measuring total, mobile (exchangeable) and water-soluble magnesium in soils and to compare different analytical methods for determining magnesium in soils and plants. &#x0D; Location and time of the study. The study site was located in the Cis-Salair drained plain in the south-east of West Siberia (55°02΄20˝N; 83°50΄00˝E), administratively being within the boundaries of the Toguchin district of the Novosibirsk region, Russia. Altitude increments were marked on the slope positions of the investigated plot of 225 hectares in area and 4 km in length: the upper part of the slope BCI (280-310 m a.s.l. ), the midslope BCII (260-280 m) and BCIII (220-260 m), and the lower slope BCIV (190-220 m) (see figure 1). Soil and plant samples were collected in July 2013. &#x0D; Materials and methods. Prevailing soils were podzolized and leached chernozems, dark-gray and gray-forest soils according to the classification of soils of the USSR (1977), which correspond to clayey-illuvial eluvialed and dark-tongue agrochernozems, agro-dark gray soils and agro-gray soils to according of the Russian soil classification (2004, 2008), or Luvic Greyzemic Chernozems, Haplic Chernozems, Luvic Greyzemic Phaeozems, Luvic Retic Greyzemic Phaeozems by WRB Soil Classification (2014) (see table 1, figure 1). Individual soil samples (n=55) were taken with a drill from 0-30 cm layer (ploughed horizon) according to an irregular grid. The aboveground phytomass stock of oat-pea mixture (n=38) was collected using the hay cutting method on the 0.25 m2 area. The geographical coordinates of the soil and plant sampling sites were determined using the geopositioning system (GPS, Garmin eTrex Vista). &#x0D; The soil samples were analyzed for organic carbon content by dichromate digestion. Overall the studied soils were grouped according to soil organic matter (SOM) content into high-SOM (5-8%) and medium-SOM soils (3-5%). Total magnesium (Mgtot) was measured in dry powdered samples by atomic emission spectrometry; mobile (exchangeable) magnesium was measured by atomic absorption spectrometry using 1 M KCl, 1 M CH3COONH4, 0.1 M C4H4O5(NH4)2 and 0.5 M CH3COOH as extracting solutions. The same extracts were used to measure water-soluble magnesium atomic absorption spectrometry and capillary electrophoresis. The content of total magnesium in plants was determined by atomic absorption spectrometry using two methods of sample digestion, namely wet ashing in a mixture of sulfuric and perchloric acids and dry ashing followed by quantitative transfer of the digest with 1 M HCl. Magnesium content in soils and plants was presented per element and calculated on the air-dry mass basis. Statistical analyses (descriptive statistics, correlation analysis, calculation of student criterion and Mann-Whitney U-test) were performed using Microsoft Office Excel 2007 and Statistica v.6.1. &#x0D; Results. The average content of total magnesium in the slope soils varied from 0.79 to 0.88%. The proportion of mobile magnesium in its total content in soils averaged 3.3-6.0%, whereas that of water-soluble magnesium was 0.06-0.13%. In medium-SOM soils down along the slope the total magnesium content gradually decreased: agrochernozems → agro-dark gray soils → agro-gray soils (see table 2, figure 2). The similar pattern was revealed an earlier for the content of total phosphorus and total potassium in the slope soils. The average content of mobile magnesium in the high-SOM soils on the upper part of the slope (BCI) varied from 3.2 to 4.0 cmol(+)ꞏkg-1, depending on the extractant used. The medium-SOM soils (BCII-IV) contained 2.2 to 3.2 cmol(+)ꞏkg-1 of mobile magnesium. Atomic absorption spectrometry and capillary electrophoresis produced very close values water-soluble magnesium content in soils: on average, 0.06-0.08 and 0.04-0.09 cmol(+)ꞏkg-1, respectively. However, capillary electrophoresis proved to be more sensitive to the decreased content of water-soluble magnesium in the midslope medium-SOM soils. Magnesium content in aboveground phytomass of an oat-pea mixture, collected in the tillering phase of its cereal component, determined by dry ashing, averaged 0.21-0.26%, which corresponded to the optimal level of the element; estimated by wet ashing it was 1.3-1.6 times lower (see table 2). &#x0D; Conclusions. Under the conditions of the sloping agrolandscape of the Cis-Salair in the south-eastern part of West Siberia, high-SOM soils in the upper part of the slope are characterized by higher content of mobile magnesium as compared with the medium-SOM soils mid- and downslope. We believe that for assessing magnesium status of soils it is more expedient to use 1 M KCl or 1 M CH3COONH4 to determine mobile (exchangeable) magnesium. Moreover, these extractants can be used for simultaneous determination of other soil properties, i.e. exchangeable calcium and potassium content, pHsalt, etc.

Age and Muscle Function Are More Closely Associated With Intracellular Magnesium, as Assessed by 31P Magnetic Resonance Spectroscopy, Than With Serum Magnesium.

Total serum magnesium is a common clinical measurement for assessing magnesium status; however, magnesium in blood represents less than 1% of the body’s total magnesium content. We measured intramuscular ionized magnesium by phosphorus magnetic resonance spectroscopy (31P-MRS) and tested the hypothesis that this measure better correlates with skeletal muscle function and captures more closely the effect of aging than the traditional measure of total serum magnesium. Data were collected from 441 participants (age 24–98 years) in the Baltimore Longitudinal Study of Aging (BLSA), a study of normative aging that encompasses a broad age range. Results showed that intramuscular ionized magnesium was negatively associated with age (β = −0.29, p < 0.001, R2 = 0.08) and positively associated with knee-extension strength (β = 0.31, p < 0.001, and R2 = 0.1 in women; and β = 0.2, p = 0.003, and R2 = 0.04 in men), while total serum magnesium showed no association with age or strength (p = 0.27 and 0.1, respectively). Intramuscular ionized magnesium was significantly lower in women that in men (p < 0.001), perhaps due to chronic latent Mg deficiency in women that is not otherwise detected by serum magnesium levels. Based on these findings, we suggest that intramuscular ionized magnesium from 31P-MRS is a better clinical measure of magnesium status than total serum magnesium, and could be measured when muscle weakness of unidentified etiology is detected. It may also be used to monitor the effectiveness of oral magnesium interventions, including supplementation.

Cistus salviifolius Toxicity in Cattle.

Toxicity related to consumption of Cistus sp. pl. has been described in ruminants in some countries. This report describes the clinical and pathological findings of Cistus salviifolius toxicosis in 3 beef cattle herds located in 2 different areas of Sicily, Italy. Outbreaks were observed after grazing in poor winter pasture where C. salviifolius was abundant. Mean morbidity and mortality were 29% and 21%, respectively. Most of the affected animals (6 to 36 months old) showed anorexia, weight loss, and pollakiuria culminating in recumbency and death. Occasionally, abortion and neurological signs were observed. In animals with acute signs, there was a moderate decrease of sodium and chloride concentrations in serum. Animals with chronic signs showed an increase of serum urea, creatine phosphokinase (CPK), aspartate transaminase (AST), lactate dehydrogenase (LDH), and phosphorus and a decrease in total serum protein, calcium, chloride, and magnesium concentrations. Moderate anemia and slight neutropenia, lymphocytosis, and eosinophilia were detected in all groups. At necropsy, the main lesion was severe distention of the urinary bladder with turbid hemorrhagic urine and crystalluria. Histologically, chronic cystitis, interstitial nephritis, eosinophilic enteritis, and nonsuppurative necrotizing hepatitis were observed. To our knowledge, this is the first report of C. salviifolius toxicosis in cattle in Italy.

Concentrations of minerals in the canine prostatic fluid.

Current knowledge about the composition of the prostate fluid in healthy male dogs is limited and restricted to small case numbers. Furthermore, published data often vary significantly regarding sample processing and analytical methods. Therefore, we aimed to provide data on the composition of electrolytes and minerals in the canine prostatic fluid in a larger population (n=30dogs/samples) and to compare these results with the existing literature. Concentrations of sodium, potassium and copper analysed in our population were most consistent with those in the literature. Different to this, concentrations of total calcium, magnesium, zinc and inorganic phosphate varied. Whereas magnesium, zinc and inorganic phosphate seemed to depend on the analysis method, total calcium concentrations differed if centrifugation was performed or not. Our results clearly indicate a need for standardization of methods for analysis of seminal plasma components.

Geochemical controls on magnesium and its speciation in various types of geothermal waters from typical felsic-rock-hosted hydrothermal systems in China

Magnesium is usually a major constituent in natural water but very likely to be depleted in high-temperature geothermal waters hosted by felsic-rocks. In the presented study, the Yunnan-Sichuan-Tibet Geothermal Province (YST) in China was selected as the study area for comprehensively investigating the geochemistry of magnesium in geothermal waters with a wide variety of pH, temperature and chemical composition. As expected, the acid geothermal waters have much higher magnesium concentrations than the neutral waters equilibrated with reservoir minerals to a higher degree. The primary alteration minerals controlling the concentrations of magnesium in neutral to alkaline geothermal waters are chlorites and saponites, as indicated by the evidence from Mg/H2 - SiO2 activity plots, calculation of saturation indices, and simulation of water-minerals reactions. It is noted that the complexation of magnesium with major anions in geothermal water also has a non-negligible effect on its total magnesium concentration because it increases the solubility of important magnesium-bearing minerals. Environmental temperature, solution pH, and salinity are the principal factors affecting the complexation between magnesium and these common anions. This is the first systematic study on the magnesium geochemistry of the hydrothermal systems in the sole high-temperature geothermal region (YST) in mainland China.

Total serum magnesium in cats with chronic kidney disease with nephrolithiasis.

Magnesium has been 'the forgotten ion' for many years. Over the past decade, however, the role of magnesium in essential physiological functions and several illness conditions have been elucidated. Nevertheless, the investigation of magnesium in cats with chronic kidney disease (CKD) and nephrolithiasis is yet to be determined. The purpose of this study was to investigate whether CKD cats with nephrolithiasis have changes in total serum magnesium concentrations, and whether magnesium disorders may be associated with other electrolyte disturbances, as well as with prognosis. We also aimed to evaluate whether total serum magnesium concentration differs between CKD cats with and without nephrolithiasis. Total serum magnesium concentrations were assessed in 42 cats with CKD with stage 1-4 nephrolithiasis. The correlation between magnesium and other electrolytes, as well as Kaplan-Meier survival analysis, were performed. We also selected 14 control cats with CKD without nephrolithiasis age-matched with 14 cats with CKD with nephrolithiasis. Hypermagnesemia was observed in 16/42 (38.1%) and hypomagnesemia in 6/42 (14.3%) cats. Serum magnesium abnormalities were observed in cats of all stages, and marked hypermagnesemia was noted in cats with stage 4 CKD with nephrolithiasis (P <0.001). There was a negative correlation between total serum magnesium and ionized calcium (r = -0.64; P <0.01), and a positive correlation between total serum magnesium and serum phosphorus (r = 0.58, P = 0.01). Cats with CKD with nephrolithiasis and hypomagnesemia or hypermagnesemia had higher mortality than those with normal total serum magnesium concentration (P <0.01), regardless of CKD stage. There was no difference in total serum magnesium concentration between CKD cats with and without nephrolithiasis. Cats with CKD with nephrolithiasis have magnesium abnormalities. Hypomagnesemia and hypermagnesemia were associated with an increase in mortality, and thus total serum magnesium abnormalities may be used as prognostic factors in these cases.

HIPOCALCEMIA EM VACAS LEITEIRAS DA AGRICULTURA FAMILIAR

Resumo O objetivo deste trabalho foi avaliar a ocorrência de hipocalcemia associada ou não a hipomagnesemia em vacas leiteiras de propriedades de agricultura familiar. Foram avaliadas 22 vacas das raças Jersey, Holandesa e Jersolando, no período de transição, oriundas de pequenas propriedades de agricultura familiar, com produção média 12L/leite/dia. A concentração do cálcio total e do magnésio séricos foi determinada por metodologia colorimétrica e cálculo do cálcio ionizado estimado a partir das concentrações séricas do cálcio total, de proteína e albumina. Foi observada hipocalcemia em 50% dos animais no pré-parto (8,2±1,4mg/dL) e 63,6% no pós-parto (7,7±1,7 mg/dL). A redução do cálcio ionizado foi menos frequente, com grande parte dos animais apresentando cálcio ionizado estimado dentro da normalidade, com média de 4,6±0,83 mg/dL no pré-parto e 4,3±1,0 mg/dL no pós-parto. Todos os animais apresentaram concentrações de magnésio sérico dentro da normalidade, descartando-se hipomagnesemia. A concentração média de magnésio no pré-parto foi 2,4±0,3 mg/dL com elevação significativa (p&lt;0,05) no pós-parto para 2,7±0,5 mg/dL. Conclui-se que as vacas leiteiras da agricultura familiar são susceptíveis à ocorrência de hipocalcemia e a ausência de sinais clínicos pode estar relacionada à manutenção da concentração de cálcio ionizado próxima da normalidade associada à ausência de hipomagnesemia.

Biochemical profile of Mangalarga Marchador mares during the last third of pregnancy, foaling and lactation

ABSTRACT: Adaptive changes in metabolism may occur under specific physiological conditions, being necessary the knowledge of the biochemical constituents that can undergo variations during the sixty days before foaling, until the first sixty days of lactation. The present study aimed to identify and evaluate the biochemical profile of Mangalarga Marchador mares during the last third of pregnancy, foaling and lactation. For this, 48 mares were used, which formed a maintenance group (MG), composed of non-pregnant mares and an experimental group, called the transition group (TG), formed by pregnant mares. Blood samples were collected at the following times: MG was evaluated in a single time (beginning of all collections); TG was evaluated in seven times [T-60, T-30, T-15 (days before foaling), T0 (first six hours after foaling), T15, T30, T60 (days after foaling)]. All animals were submitted to biochemical analysis, in which the concentrations of total calcium, chloride, phosphorus, magnesium, sodium, potassium, uric acid, creatinine, and urea were measured. The two groups differed significantly (P&lt;0.05) in calcium, magnesium, sodium, potassium, creatinine, uric acid and urea concentration. Variation between times was also observed for these compounds. However, chloride and phosphorus did not differ between MG and TG. It was concluded that the last third of pregnancy, foaling and lactation exerts major influence on the biochemical constituents of blood through adjustments to maintain homeostasis in mares.