Synergistic allelochemicals from a freshwater cyanobacterium

The ability of cyanobacteria to produce complex secondary metabolites with potent biological activities has gathered considerable attention due to their potential therapeutic and agrochemical applications. However, the precise physiological or ecological roles played by a majority of these metabolites have remained elusive. Several studies have shown that cyanobacteria are able to interfere with other organisms in their communities through the release of compounds into the surrounding medium, a phenomenon usually referred to as allelopathy. Exudates from the freshwater cyanobacterium Oscillatoria sp. had previously been shown to inhibit the green microalga Chlorella vulgaris. In this study, we observed that maximal allelopathic activity is highest in early growth stages of the cyanobacterium, and this provided sufficient material for isolation and chemical characterization of active compounds that inhibited the growth of C. vulgaris. Using a bioassay-guided approach, we isolated and structurally characterized these metabolites as cyclic peptides containing several unusually modified amino acids that are found both in the cells and in the spent media of Oscillatoria sp. cultures. Strikingly, only the mixture of the two most abundant metabolites in the cells was active toward C. vulgaris. Synergism was also observed in a lung cancer cell cytotoxicity assay. The binary mixture inhibited other phytoplanktonic organisms, supporting a natural function of this synergistic mixture of metabolites as allelochemicals.     

The Influence of Proinflammatory Factors on the Neuroprotective Efficiency of Multipotent Mesenchymal Stromal Cells in Traumatic Brain Injury

Bulletin of Experimental Biology and Medicine - We studied the neuroprotective potential of multipotent mesenchymal stromal cells in traumatic brain injury and the effect of inflammatory...     

Memory retrieval along the proximodistal axis of CA1

The proximal and distal segments of CA1 are thought to perform distinct computations. Neurons in proximal CA1 are reciprocally connected with the medial entorhinal cortex (MEC) and exhibit precise spatial firing. In contrast, cells in distal CA1 communicate with the lateral entorhinal cortex (LEC), exhibit more diffuse spatial firing and are affected by the presence of objects in the environment. To determine if these segments make unique contributions to memory retrieval, we examined cellular activity along the proximodistal axis of CA1 using transgenic reporter mice. Neurons tagged during context learning in proximal CA1 were more likely to be reactivated during testing than those in distal CA1. This was true following context fear conditioning and after exposure to a novel environment. Reactivation was also higher in brain regions connected to proximal CA1 (MEC, distal CA3) than those connected to the distal segment (LEC, proximal CA3). To examine contributions to memory retrieval, we performed neurotoxic lesions of proximal or distal CA1 after training. Lesions of the proximal segment significantly impaired memory retrieval while damage to distal CA1 had no effect. These data suggest that context memories are retrieved by a hippocampal microcircuit that involves the proximal but not distal segment of CA1. © 2016 Wiley Periodicals, Inc.     

Blood Transfusion Practices in Military Medicine

Background

This observational study was conducted in a small, 45 bed border static hospital, located in a field area, where no blood bank facilities were available. The present study was conducted to elucidate the blood transfusion practices of this hospital. Methods: A retrospective analysis of all blood transfusions performed in this hospital between Dec 2004 and Dec 2006 was carried out. The data collection included blood group patterns, common indications, haemoglobin levels and complications of blood transfusion. Inferences were based on available data and relevant statistical analysis.

Result

A total of 246 blood transfusions were administered to 79 recipients during the study period. Only one patient had an Rh negative blood group. The most frequently transfused blood group was A Rh positive. Majority of transfusions were administered to surgical cases and the commonest indication was gunshot wounds with haemorrhagic shock. The mean haemoglobin at admission was 8.93 g/dl. The mean number of blood transfusions per patient was 3.13. No haemolytic or other transfusion reactions occurred in any of the transfusions.

Conclusion

This study demonstrates that blood transfusions can be safely administered in field conditions despite constraints of not having a blood bank.Key Words: Blood transfusion practices, Haemoglobin, Anaemia     

Comparative efficacy and tolerance of atenolol and midodrine in patients with vasovagal syncopes

AIM: To compare efficacy and tolerance of atenolol and midodrine in patients with vasovagal syncopes (VVS). MATERIAL AND METHODS: The trial included 35 patients with recurrent VVS confirmed at long passive head-up tilt table test (HTTT) or maximal load bicycle exercise test (MET). These tests were also used for assessing efficacy of atenolol and midodrine in cases when syncopes occur in repeated tests. If recurrent induction of VVS was absent, efficacy of the drugs was assessed by long-term (up to 12 months) clinical observation. Long-term administration of atenolol and midodrine was continued in patients with effect by HTTT and/or MET. Eighteen patients were randomized to take atenolol in a daily dose up to 50 mg, seventeen--to take midodrine in a daily dose up to 15 mg. RESULTS: Efficacy of atenolol by HTTT and MET was 8%, midodrine--57% (p = 0.01). All the patients benefited from the drugs in their long-term regimen. Long-term administration of atenolol induced remission of VVS in 82% cases, midodrine--in 89% (insignificant). Overall efficacy of atenolol was 44%, of midodrine--70% (insignificant). In 5 of 6 patients resistant to atenolol and midodrine monotherapy, combined use of the drugs was effective. Treatment with atenolol, midodrine and their combination prevented VVS in 89% patients. Both short- and long-term courses of atenolol and midodrine were safe in terms of side effects. CONCLUSION: Atenolol and midodrine as well as their combination were highly effective and well tolerated in the treatment of VVS patients.