Effect of Chronic Administration of Magnesium Sulfate on 1–Methyl–4–phenyl–1,2,3,6–tetrahydropyridine–Induced Neurotoxicity in Mice

Abstract: This investigation was aimed to study the effect of magnesium on 1–methyl–4–phenyl–1,2,3,6–tetrahydropyridine (MPTP)–induced neurotoxicity in mice. Four groups of mice were given magnesium sulfate (MgSO₄.7H₂O) in drinking water at four different concentrations of 0.0 g/l (control), 2.5 g/l (low), 5.0 g/l (medium) and 10.0 g/l (high) respectively for a period of 16 weeks; these animals also received MPTP (30 mg/kg, intraperitoneally daily) during the last five days of Mg treatment. Other four groups of mice were given similar dose regimen of MgSO₄ but received injections of saline instead of MPTP. Seventy–two hr after the last dose of MPTP, neurobehavioural studies including locomotor activity, pole climbing test and heat nociception test were performed and striata were collected for the analysis of dopamine. The results of this study show that treatment of mice with MgSO₄ or MPTP individually has no effect on their behaviour. Concomitant administration of low dose of MgSO₄ (2.5 g/l) along with MPTP produced increase in motor activity and latency to heat stimuli; whereas medium and high doses of MgSO₄ in combination with MPTP produced opposite (as compared to low dose) effects resulting in a decrease in motor activity and latency to heal stimuli and increase in pole climbing time. However, MgSO₄ dose–dependently exacerbated MPTP–induced depletion of striatal dopamine. The mortality was drastically increased (30–55%) in the animals receiving combined treatments of MPTP and MgSO₄ as compared to the mice treated with MPTP alone (12%). This study clearly points towards the ability of MgSO₄ to modify MPTP–induced neurotoxicity.     

Long-term immunosuppression and multiple transplants predispose systemic lupus erythematosus patients with cytopenias to hematologic malignancies

Cytopenias in systemic lupus erythematosus (SLE) require clinical and laboratory workup and bone marrow (BM) examination to determine the cause and for appropriate patient management. Common causes include an increase in SLE activity, immune-mediated hemolysis, iron deficiency, antiphospholipid antibody syndrome, infection, or the effect of medications. We retrospectively evaluated the clinical and laboratory findings of patients with SLE and cytopenias who had undergone BM studies to determine the indicators of malignancy.We retrospectively reviewed medical records of patients with SLE who presented with cytopenias for their disease course, medications, laboratory parameters and documented the spectrum of morphological changes in BM including CD34 expression.Twenty patients with SLE had undergone BM biopsy for evaluation of cytopenias. 14/20 (70%) of the patients had reactive BM, and the rest had hematologic malignancies involving the BM. Of these 14 patients, 8 had hypocellular marrow with loss of precursor cells (low CD34), 4 had left shift in myeloid lineage, 3 had serous atrophy, and 1had multilineage dysplasia. The 6 patients with hematologic malignancies included 2 with diffuse large B cell lymphoma, and one each of natural killer/T cell lymphoma, post-transplant lymphoproliferative disorder, Hodgkin lymphoma, and myelodysplastic syndrome evolving to acute myelogenous leukemia. The presence of autoantibodies, SLE activity, and lupus nephritis were comparable in patients with and without neoplasia. However, the duration of the use of multiple immunosuppressants, years since renal transplant (22 vs 10), multiple transplants, and the presence of other autoimmune diseases were greater in those with neoplasia. Two of the 14 patients with non-neoplastic BM and 1 with the neoplastic BM had nonhematological malignancy.Clinical and laboratory findings, the number of transplants, and the use of immunosuppressive agents can guide physicians to identify patients with a higher risk of developing hematologic malignancy. BM findings of cytopenia in SLE are often due to increased disease activity causing global cell death and dysmaturation. SLE patients presenting with cytopenias, with a history of long-term exposure to immunosuppressive drugs, should be regularly screened for hematologic and nonhematologic malignancies.     

Differential effects of dietary saturated and trans-fatty acids on expression of genes associated with insulin sensitivity in rat adipose tissue

OBJECTIVE: Trans-fatty acids (TFAs) are formed during partial hydrogenation of vegetable oils and are shown to be more atherogenic than saturated fatty acids (SFAs). Our previous study showed that dietary TFAs decrease adipose tissue insulin sensitivity to a greater extent than SFAs in rats. We hypothesized that the effects of these fatty acids on insulin sensitivity could be mediated through an alteration in gene expression. In the current study we have investigated the effects of dietary TFAs or SFAs on expression of genes associated with insulin sensitivity in rat adipose tissue. DESIGN AND METHODS: Male weanling Wistar/NIN rats were divided into four groups and fed one of the following diets containing 10% fat (g/100 g diet) differing only in the fatty acid composition for 3 months: control diet (3.7% linoleic acid (LA)), SFA diet (5% SFA), TFA diet 1 (1.5% TFA + 1% LA) and TFA diet 2 (1.5% TFA + 2% LA). The mRNA expression of peroxisome proliferator-activated receptor gamma (PPARgamma), lipoprotein lipase (LPL), glucose transporter-4 (GLUT4), resistin and adiponectin was analyzed in epididymal fat using RT-PCR. The effects of TFA were studied at two levels of LA to understand the beneficial effects of LA over the effects of TFA. RESULTS: Both dietary SFA and TFA upregulated the mRNA levels of resistin. Dietary SFA downregulated adiponectin and GLUT4 and upregulated LPL, while TFA downregulated PPARgamma and LPL. The effects of dietary TFA on PPARgamma and resistin were not counteracted by increased LA (TFA diet 2). CONCLUSION: The effects of SFAs on the aforementioned genes except PPARgamma could be extrapolated towards decreased insulin sensitivity, while only the alteration in the mRNA levels of PPARgamma and resistin could be associated with insulin resistance in TFA-fed rats. These findings suggest that dietary SFAs and TFAs alter the expression of different genes associated with insulin sensitivity in adipose tissue.     

Dead on arrival in a low-income country: results from a multicenter study in Pakistan

Background

This study assessed the characteristics of dead on arrival (DOA) patients in Pakistan.

Methods

Data about the DOA patients were extracted from Pakistan National Emergency Department Surveillance study (Pak-NEDS). This study recruited all ED patients presenting to seven tertiary care hospitals during a four-month period between November 2010 and March 2011. This study included patients who were declared dead-on-arrival by the ED physician.

Results

A total of 1,557 DOA patients (7 per 1,000 visits) were included in the Pak-NEDS. Men accounted for two-thirds (64%) of DOA patients. Those aged 20-49 years accounted for about 46% of DOA patients. Nine percent (n = 72) of patients were brought by ambulance, and most patients presented at a public hospital (80%). About 11% of DOA patients had an injury. Factors significantly associated (p < 0.05) with ambulance use were men (adjusted odds ratio [aOR] = 2.72), brought to a private hospital (OR = 2.74), and being injured (aOR = 1.89). Cardiopulmonary resuscitation (CPR) was performed on 6% (n = 42) of patients who received treatment. Those brought to a private hospital were more likely to receive CPR (aOR = 2.81).

Conclusion

This study noted a higher burden of DOA patients in Pakistan compared to other resourceful settings (about 1 to 2 per 1,000 visits). A large proportion of patients belonging to productive age groups, and the low prevalence of ambulance and CPR use, indicate a need for improving the prehospital care and basic life support training in Pakistan.

     

Do observational studies using propensity score methods agree with randomized trials? A systematic comparison of studies on acute coronary syndromes

Aims Randomized controlled trials (RCTs) are the gold standard for assessing the efficacy of therapeutic interventions because randomization protects from biases inherent in observational studies. Propensity score (PS) methods, proposed as a potential solution to confounding of the treatment-outcome association, are widely used in observational studies of therapeutic interventions for acute coronary syndromes (ACS). We aimed to systematically assess agreement between observational studies using PS methods and RCTs on therapeutic interventions for ACS. Methods and results We searched for observational studies of interventions for ACS that used PS methods to estimate treatment effects on short- or long-term mortality. Using a standardized algorithm, we matched observational studies to RCTs based on patients' characteristics, interventions, and outcomes ('topics'), and we compared estimates of treatment effect between the two designs. When multiple observational studies or RCTs were identified for the same topic, we performed a meta-analysis and used the summary relative risk for comparisons. We matched 21 observational studies investigating 17 distinct clinical topics to 63 RCTs (median = 3 RCTs per observational study) for short-term (7 topics) and long-term (10 topics) mortality. Estimates from PS analyses differed statistically significantly from randomized evidence in two instances; however, observational studies reported more extreme beneficial treatment effects compared with RCTs in 13 of 17 instances (P = 0.049). Sensitivity analyses limited to large RCTs, and using alternative meta-analysis models yielded similar results. Conclusion For the treatment of ACS, observational studies using PS methods produce treatment effect estimates that are of more extreme magnitude compared with those from RCTs, although the differences are rarely statistically significant.