Experimental system to displace radioisotopes from upper to deeper soil layers: chemical research

BACKGROUND: Radioisotopes are introduced into the environment following nuclear power plant accidents or nuclear weapons tests. The immobility of these radioactive elements in uppermost soil layers represents a problem for human health, since they can easily be incorporated in the food chain. Preventing their assimilation by plants may be a first step towards the total recovery of contaminated areas. METHODS: The possibility of displacing radionuclides from the most superficial soil layers and their subsequent stabilisation at lower levels were investigated in laboratory trials. An experimental system reproducing the environmental conditions of contaminated areas was designed in plastic columns. A radiopolluted soil sample was treated with solutions containing ions normally used in fertilisation (NO(3)(-), NH(4)(+), PO(4)(--- )and K(+)). RESULTS: Contaminated soils treated with an acid solution of ions NO(3)(-), PO(4)(--- )and K(+), undergo a reduction of radioactivity up to 35%, after a series of washes which simulate one year's rainfall. The capacity of the deepest soil layers to immobilize the radionuclides percolated from the superficial layers was also confirmed. CONCLUSION: The migration of radionuclides towards deeper soil layers, following chemical treatments, and their subsequent stabilization reduces bioavailability in the uppermost soil horizon, preventing at the same time their transfer into the water-bearing stratum

Ornipressin (Por 8): An efficient alternative to counteract hypotension during combined general/epidural anesthesia.

We sought to evaluate the efficacy and side effect profile of a small dose of ornipressin, a vasopressin agonist specific for the V1 receptor, administered to reverse the hypotension associated with combined general/epidural anesthesia. A total of 60 patients undergoing intestinal surgery were studied. After the induction of anesthesia, 7-8 mL of bupivacaine 0.5% with 2 microg/kg clonidine and 0.05 microg/kg sufentanil after an infusion of 5 mL of bupivacaine 0.06% with 0.5 microg x kg(-1) x h(-1) clonidine and 0.1 microg/h of sufentanil were administered by an epidural catheter placed at T7-8 vertebral interspace. When 20% reduction of baseline arterial blood pressure developed, patients were randomly assigned to receive, in a double-blinded design, dopamine started at 2 microg x kg(-1) x min(-1), norepinephrine started at 0.04 microg x kg(-1) x min(-1), or ornipressin started at 1 IU/h. Fifteen patients presenting without hypotension were used as control subjects. Beside routine monitoring, S-T segment analysis, arterial lactacidemia, and gastric tonometry were performed. Ornipressin restored arterial blood pressure after 8 +/- 2 vs 7 +/- 3 min in the norepinephrine group and 11 +/- 3 min in the dopamine group (P < 0.05). This effect was achieved with 2 IU/h of ornipressin in most of the patients (11 of 15). Ornipressin did not induce any modification of the S-T segment; however, it significantly increased intracellular gastric PCO(2) (P < 0.05), indicating splanchnic vasoconstriction. Implications: In the population studied, small-dose ornipressin was effective to restore arterial blood pressure without causing major ischemic side effects

Extracorporeal membrane oxygenation rescue therapy in a case of portopulmonary hypertension during liver transplantation: A case report

Portopulmonary hypertension has been reported in 2% to 9% of candidates for liver transplantation (OLT). If it is moderate to severe, it represents a contraindication to the procedure until pulmonary vasodilatative therapy has been optimized. We report the case of a 43-year-old man, scheduled for OLT due to alcoholic cirrhosis with hemosiderosis. His Model for End-Stage Liver Disease was 25 at that time. The preoperative evaluation showed a severe alteration of diffusion (pO2 68 mm Hg), without hepatopulmonary syndrome or portopulmonary hypertension (PPH) upon basal and dobutamine stress echocardiography. At the beginning of the OLT the hemodynamic profile showed mean pulmonary artery pressure (mPAP) 38 mm Hg, wedge pressure (WP) 19 mm Hg, cardiac output (CO) 9.1 L/min, pulmonary vascular resistance (PVR) 166 dyne s/cm5, transpulmonary gradient (TPG) 19 mm Hg, which lead us to promptly initiate inhaled nitric oxide (iNO) and intravenous epoprostenol 2 to 5 ng/kg/min. Upon graft reperfusion the hemodynamic profile was: mPAP 47 mm Hg, WP 23 mm Hg, CO 14.2 L/min, PVR 135 dyne s/cm5, TPG 24 mm Hg, and at the end of surgery, mPAP 39 mm Hg, WP 20 mm Hg, CO 10.6 L/min, PVR 123 dyne s/cm5, TPG 19 mm Hg. On postoperative day (POD) 3, we observed severe worsening of PPH: mPAP 60 mm Hg, WP 10 mm Hg, CO 9.8 L/min, PVR 395 dyne s/cm5, TPG 50 mm Hg even with maximal pulmonary vasodilatatory therapy (ambrisentan 5 mg, intravenous sildenafil 20 mg 7 3 and epoprostenol 22 ng/kg/min, iNO). Severe acute respiratory distress syndrome (ARDS) was presents. Therefore we decided to begin veno-venous extracorporeal membrane oxygenation (v-v ECMO) to correct the hypoxic vasoconstriction. Subsequent weaning from inotropic support with iNO and epoprostenol was possible on POD 7 due to mPAP 42 mm Hg, WP 15 mm Hg, CO 7.9 L/min, PVR 273 dyne s/cm5, and TPG 27 mm Hg. On POD 11 he was weaned from ECMO due to: mPAP 40 mm Hg, WP 16 mm Hg, CO 6.5 L/min, PVR 295 dyne s/cm5 and TPG 24 mm Hg. The patient was extubated on POD 17. The cardiac catheterization 1 month after OLT showed: mPAP 28 mm Hg, WP 13 mm Hg, CO 5.4 L/min, PVR 220 dyne s/cm5 and TPG 15 mm Hg. ECMO rescue therapy in this "extreme" case allowed us to correct hypoxemia responsible for worsening of pulmonary hypertension allowing time to reach the goal of vasodilatatory therapy. \ua9 2013 by Elsevier Inc. All rights reserved