Intravenous infusion of magnesium sulfate is not associated with cardiovascular, liver, kidney, and metabolic toxicity in adults

BACKGROUND

Magnesium (Mg) deficiency contributes to the pathophysiology of numerous diseases. The therapeutic use of Mg has steadily increased over time. The increased in-hospital use of intravenous (IV) magnesium sulfate (MgSO4) warrants more extensive investigation regarding the safety of the therapy. The aim of this study was to determine the safety of IV MgSO4 infusion on cardiovascular, liver, kidney, and metabolic markers in adults.

METHODS

Twelve volunteers were randomized to one of two cross-over conditions: (a) IV infusion of MgSO4 in 5% dextrose followed by IV infusion of 5% dextrose 1 week later or (b) IV infusion of 5% dextrose followed by IV infusion of MgSO4 in 5% dextrose 1 week later. An electrocardiogram was recorded continuously during the infusions. Blood was drawn pre- and post-infusion for blood count (high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides). Results: Serum Mg increased from pre- to post-infusion in the MgSO4 + 5% dextrose group (p < 0.0001). The QRS interval length increased from pre- to post-infusion in the MgSO4 + 5% dextrose group (p < 0.04). Additionally, serum glucose concentration increased in the MgSO4 + 5% dextrose group (p = 0.04). These significant findings were modeled with gender and age as covariates. No other significant differences were found.

CONCLUSIONS

The administration of IV infusion of MgSO4 (4 g/100 mL) in 5% dextrose over a 4-hour treatment period poses no significant deleterious effects on cardiovascular, liver, kidney, or metabolic function.

RELEVANCE FOR PATIENTS

IV infusion of MgSO4 may be used for certain treatment indications without significant concern for systemic or organ toxicity.

Stochastic Chaos in a Turbulent Swirling Flow

We report the experimental evidence of the existence of a random attractor in a fully developed turbulent swirling flow. By defining a global observable which tracks the asymmetry in the flux of angular momentum imparted to the flow, we can first reconstruct the associated turbulent attractor and then follow its route towards chaos. We further show that the experimental attractor can be modeled by stochastic Duffing equations, that match the quantitative properties of the experimental flow, namely, the number of quasistationary states and transition rates among them, the effective dimensions, and the continuity of the first Lyapunov exponents. Such properties can be recovered neither using deterministic models nor using stochastic differential equations based on effective potentials obtained by inverting the probability distributions of the experimental global observables. Our findings open the way to low-dimensional modeling of systems featuring a large number of degrees of freedom and multiple quasistationary states.

Double-blind, randomized crossover study of intravenous infusion of magnesium sulfate versus 5% dextrose on depressive symptoms in adults with treatment-resistant depression

AIM

Treatment-resistant depression patients are more likely to suffer from comorbid physical and mental disorders, experience marked and protracted functional impairment, and incur higher health-care costs than non-affected individuals. Magnesium sulfate is a treatment option that may offer great potential for patients with treatment-resistant depression based on prior work in animals and humans.

METHODS

Twelve subjects with mild or moderate treatment-resistant depression were randomized into a double-blind crossover trial to receive an infusion of 4 g of magnesium sulfate in 5% dextrose or placebo infusion of 5% dextrose with a 5-day washout in between the 8-day intervention period. Subjects were assessed before and after the intervention for serum and urine magnesium, lipid panel, the Hamilton Rating Scale for Depression, and the Patient Health Questionnaire-9.

RESULTS

We found a difference in serum magnesium from day 2 to 8 (pre-infusion) (P < 0.002) and from baseline to day 8 (P < 0.02). No changes were noted on the Hamilton Rating Scale for Depression or the Patient Health Questionnaire-9 24 h post-treatment, but as serum magnesium increased from baseline to day 7, the Patient Health Questionnaire-9 decreased from baseline to day 7 (P = 0.02).

CONCLUSION

Magnesium sulfate did not significantly affect depression 24 h post-infusion, but other results were consistent with the literature. The association between changes in serum magnesium and the Patient Health Questionnaire-9 supports the idea that magnesium sulfate may be used to address treatment-resistant depression, an ongoing medical challenge.

First Report of Grapevine leafroll-associated virus 5 in Spain

Grapevine leafroll-associated viruses (GLRaVs) cause significant reductions in yield and quality in the wine industry worldwide. At least nine different GLRaVs have been found in different regions of the world. In the process of virus indexing of candidate grapevine clones for certification, which includes grafting of scions onto rootstocks, we observed strong leafroll symptoms 1 year after grafting with one vine of cv. Estaladina in Castilla y León, Spain and one vine of cv. Tempranillo in La Rioja, Spain, collected in 2008 and 2007, respectively. Both vines tested positive by real-time reverse transcription (RT)-PCR with TaqMan probes specific for Grapevine leafroll-associated virus 5 and double-antibody sandwich (DAS)-ELISA with a mix of monoclonal antibodies that recognizes GLRaV-4, 5, 6, 7, and 9 (Bioreba, Reinach, Switzerland). RNA extracts of both GLRaV-5 positive vines were analyzed by conventional RT-PCR with a pair of consensus degenerated primers derived from GLRaV-5 hsp70 sequences available in GenBank: LR5HYF (5'-TGGGATGAAYAARTTCAATGC-3') and LR5HYR (5'-TGAAATTCCTCATRTARGAGC-3') that amplified a 250-bp fragment. Amplicons were cloned and the comparison of the amino acid sequences (Estaladina isolate, Est110: Accession No. HM208622; Tempranillo isolate, Tem020: Accession No. HM208618) showed in the case of the Est110 isolate, 100 and 82.6% identity, respectively, with the homologous genes of one GLRaV-5 isolate from the United States (AF233934 [3]) and Argentina (EU815935 [2]). For isolate Tem020, the hsp70 gene showed 97.1 and 81.2% amino acid identity with the homologous hsp70 genes of the United States and Argentina isolates. The coat protein (cp) genes of both isolates were also amplified and cloned using the specific GLRaV-5 primers, LR53413 (5'-CGTGATACAAGGTAGGACAACCGT-3') and LR53843 (5'-CTTGCACTATCGCTGCCGTGAAT-3'), designed according to the sequence of AF233934. Fragments were of the expected size (430 bp) and the nucleotide sequences were obtained (Est110: Accession No. HM363522; Tem020: Accession No. HM363523) and used for pairwise nucleotide comparisons. The Est110 isolate showed 96.7 and 97.5% amino acid identity with the isolates from the United States and Argentina, respectively, while the Tem020 isolate showed 94.8 and 95.6% identity, respectively. Amino acid identity of Est110 and Tem020 cp genes was 100% when compared with the homologous genes of isolates AF233934 and EU815935. To our knowledge this is the first report of GRLaV-5 in Spain. Since 2008, we have detected eight additional vines positive for this virus in 200 clones analyzed for certification, suggesting that the incidence of GLRaV-5 in Spain could be widespread. This research indicates that virus indexing for GLRaV should be included in certification schemes for grapevine candidate clones (1) in Spain. References: (1) Anonymous. OEPP/EPPO Bull. 38:422, 2008. (2) S. Gomez Talquenca et al. Virus Genes 38:184, 2009. (3) F. Osman et al. J. Virol. Methods 141:22, 2007.

First Report of Arabis mosaic virus on Grapevine in Spain

Arabis mosaic virus (ArMV; genus Nepovirus, family Comoviridae) is one of several nepoviruses responsible for infectious degeneration disease of grapevines in Europe (3). The first occurrence in Spain, in the summer of 2007, was found in Val de Salnés, Rias Baixas appellation, Galice on 25-year-old vines of the Albariño variety grafted onto an unidentified rootstock and showing leaf yellowing. The second finding was in the spring of 2008 in Barriobusto, Rioja appellation, Basque Country on 30-year-old vines of Tempranillo variety grafted onto 41B rootstock. In this case, no obvious foliar symptoms were observed but fruit set was very poor. Positive ELISA results were obtained at two different laboratories using antibodies to ArMV obtained from two companies (BIOREBA, Reinach, Switzerland and Sediag, Longvic, France). At a third lab, the presence of ArMV was further confirmed by reverse transcription (RT)-nested PCR using the primers described by Bertolini et al. (1). External primers ArMV 1 and ArMV 2 amplified a fragment of 340 bp from the coat protein region of the virus and internal primers ArMV i1 and ArMV i2 amplified a fragment of 203 bp. The specificity of the amplicons was subsequently confirmed by sequencing and comparison with other ArMV isolates available in the GenBank, EMBL, and DDBJ databases. Alignment performed using Blastn showed 85% nucleotide sequence identity with ArMV isolate NW (Accession No. AY017339). ELISA revealed co-infection with GLRaV-1 in Galice, GLRaV-3 in Rioja, and GFkV at both sites; these other viruses being common in their respective appellations. ArMV could be mechanically transmitted from rooted cuttings onto Chenopodium amaranticolor with an average of a 46% success rate (1:10 tissue/buffer ratio; [2]), but the range was very wide (0 to 100%) and dependent on the individual source vine. No statistical differences were found between nicotine or phosphate buffer for extraction or when using shoot tips or root tips as a source of virus (Fisher's exact test). Infection in C. amaranticolor was symptomless, but detectable by ELISA, and systemic. The Galician grapevine was an isolated plant, replanted on the spot of a dead one. Xiphinema diversicaudatum, the nematode vector of ArMV, was found in the vineyard soil. Only two ArMV-positive vines were found among 1,993 plants analyzed in Galice from 2005 to 2007 (no field data available for the second finding). In Rioja, one positive vine was found in a random sample of 74 vines from two different vineyards. Further testing of the neighboring vines indicated that one of the adjacent plants was also infected. This minimal spread since the vineyard was planted is suggestive of a lack of vectored transmission. In Spain as a whole, the virus seems to be rare and associated with the Atlantic biogeographic region. Both vineyards were planted before certified material became widely available. Currently, statutory testing of grapevine propagation material should prevent further spread. References: (1) E. Bertolini et al. Phytopathology 93:286, 2003. (2) G. P. Martelli, ed. Graft-Transmissible Diseases of Grapevines. Handbook for Detection and Diagnosis, FAO, Rome, 1993. (3) G. P. Martelli and E. Boudon-Padieu. Directory of Infectious Diseases of Grapevines and Viruses and Virus-like Diseases of the Grapevine. Bibliographic Report 1998-2004, CIHEAM, Paris, 2006.