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Background&Objective: Electromagnetic fields are present everywhere in our environment with various intensities, so, investigation about their effects on living organism is very important. The aim of this experiment study to investigate the effect of magnetic field on bone resorption, PTH and calcitonin concentration and their correlations. Materials&Methods: In this experimental research, 30 Sprague-Dawley male rats were divided into 3 groups. Test group animals, were exposed to magnetic field (100µT, 50 Hz), 4 hours per day for a period of 42 days. Experimental condition for control-1 group was the same as test group, except that, they were not exposed. Animals of control-2 group were killed at the first day of experiment (day 0). Total left femoral bone calcium and phosphorus content and its fracture energy was measured at days 28 and 42 in control-1 and test group and on day 0 in control-2 group. However, serum calcium, phosphorus, PTH and calcitonin concentration were measured on day 0, the first day of exposure, and thereafter once per two weeks. Results: Total bone calcium content in test group was significantly lower than control-1 and 2 groups, and bone fracture energy showed a slightly decrease. On the other hand, serum calcium and phosphorus concentration increased significantly on 28th and 42nd days compared to day 0. There was a decrement in serum PTH concentration and increment in serum calcitonin concentration during the exposure period. Conclusion: Our results suggested that magnetic field could have a direct effect on bone resorption, and observed changes in PTH and calcitonin were in good correlation with serum calcium and phosphorus concentrations (negative feed back) and these changes also prevent further increase in bone resorption.

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Background and Objective: Calcitonin is a small peptide hormone including 32 amino acids and 3.4 KD molecular weight which is produced by the parafollicular cells of the thyroid gland in respond to increasing calcium ions in serum. This peptide is used for adjuvant therapy of osteoporosis, Paget's disease and hypercalcemic shock. In this study, the heterologuse expression of calcitonin was done in Escherichia coli.

Methods: In this experimental study, the thioredoxin fusion partner was added to n-terminal of the Salmon calciton in order to increase its stability by the synthetic biology. The recombinant construct was transformed and over expressed into Escherichia coli BL21 (DE3) host cell.

Results: SDS-PAGE analysis showed the over expression of recombinant protein after IPTG induction.

Conclusion: In this study, the construct including fused Salmon calcitonin gene with thioredoxin was cloned. The SDS-PAGE result showed the stable expression of fused calcitonin.

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Background and Objective: Ventilator-associated pneumonia (VAP) is an important complication in intensive care unit (ICU) patients with endotracheal intubation. Finding potential early indicators of this condition can aid in reducing the disease burden. We aimed to investigate the relationship between VAP occurrence and serum levels of C-reactive protein (CRP), procalcitonin (PCT), and hemoglobin (Hgb) during ICU hospitalization of brain trauma patients.
Method: This descriptive-analytical study was carried out on brain trauma patients (99 male, 39 female), referring to the 5th Azar hospital in Gorgan, Iran, in the course of 2017. The patients were hospitalized in ICU with endotracheal intubation and mechanical ventilation. The diagnosis of VAP was confirmed by a 12-score rating based on chest radiographs, body temperature, white blood cell count, and sputum culture. After admission, serum CRP, PCT, and Hgb were documented daily for 6 days.
Results: According to the diagnostic criteria, VAP was confirmed in 41 patients (30%). Serum CRP and PCT levels on the 6th-day post-admission were significantly associated with VAP diagnosis, while Hgb levels did not differ significantly between VAP and non-VAP patients. Serum levels of CRP, PCT, and Hgb on the 6th day were not associated with age or sex.
Conclusion: Our results indicate that serum CRP and PCT levels are associated with the occurrence of VAP in ICU patients receiving mechanical ventilation. Therefore, these biomarkers could be utilized to warn physicians about the possibility of VAP, thereby reducing mortality rate and hospitalization length.