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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Survival of V-79 Chinese hamster cells was assessed by colony growth assay after hypothermic exposure in the presence of iron chelators. At 5 degrees C, maximum protection from hypothermic damage was achieved with a 50 microM concentration of the intracellular ferric iron chelator Desferal. A 3-hr prehypothermic incubation with 50 microM Desferal followed by replacement with chelator-free medium at 5 degrees C also provided some protection. This was not observed when the extracellular chelator DETA-PAC (50 microM) was used prior to cold storage. Treating 5 degrees C-stored cells with Desferal just prior to rewarming was ineffective, but treating cells with Desferal during hypothermia exposure after a significant period of unprotected cold exposure ultimately increased the surviving fraction. Submaximal protection during hypothermia was achieved to various degrees with extracellular chelators at 5 degrees C, including 50 microM DETAPAC and 110 microM EDTA. EGTA (110 microM) had little effect. The sensitization of cells at 5 degrees C with 200 microM FeCl3 could be reduced or eliminated with Desferal in accordance with a 1:1 binding ratio. At 10 degrees C, 50 microM Desferal, 50 microM DETAPAC, and 110 microM EDTA were as or less effective in protecting cells than at 5 degrees C. An Arrhenius plot of cell inactivation rates shows a break at 7-8 degrees C, corresponding to maximum survival for control cells and cells in 50 microM Desferal; however, the amount of protection offered by the chelator increases with decreasing temperature below about 19 degrees C, and sensitization increases above that point. It has not previously been shown that iron chelators protect against cellular hypothermia damage which is uncomplicated by previous or simultaneous ischemia. This may be relevant to the low-temperature storage of transplant organs, in which iron of intracellular origin and in the perfusate may be active and damaging.
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PMID:Factors influencing survival of mammalian cells exposed to hypothermia. IV. Effects of iron chelation. 239 29

PURPOSE Anatrophic nephrolithotomy performed via open surgery involves incising the renal parenchyma along an avascular plane to remove a large, complex renal stone. We determined the feasibility of performing laparoscopic anatrophic nephrolithotomy in a survival porcine model. Furthermore, we present a novel technique of creating a staghorn calculus in the porcine model. MATERIALS AND METHODS After developing the technique in 3 pigs the survival study was performed in 10 consecutive animals. The procedure comprised 2 aspects. 1) We developed an animal model for staghorn calculi by retrograde injection of polyurethane (Fomo Products, Inc., Norton, Ohio) into the renal pelvis through a ureteral catheter. For a 2-week period the staghorn calculus was allowed to create hydronephrosis. 2) Laparoscopic anatrophic nephrolithotomy was done, involving control of the renal artery and vein, in situ renal hypothermia with ice slush in 1 animal, lateral renal parenchymal incision, stone extraction and suture repair of the incised collecting system and renal parenchyma. RESULTS Synthetic stone formation and laparoscopic anatrophic nephrolithotomy were successful in all 10 animals, including 1 that underwent staged bilateral anatrophic nephrolithotomy. Mean operative time for anatrophic nephrolithotomy was 125 minutes. Mean blood loss was 68 cc and mean warm ischemia time was 30 minutes (range 23 to 39). A residual small pelvicaliceal calculus was noted postoperatively in the initial 3 cases only. Thereafter, routine intraoperative ultrasonography and flexible endoscopy were done for stone localization, resulting in a stone-free rate of 100% in all 7 remaining animals. Diethylenetriamine pentaacetic acid renal scans documented improvement in the glomerular filtration rate from a mean of 26.4 ml. per minute after stone creation and hydronephrosis to 54.8 ml. per minute 4 to 5 weeks after laparoscopic anatrophic nephrolithotomy. CONCLUSIONS Laparoscopic techniques can be applied to complex stone surgery such as anatrophic nephrolithotomy with encouraging surgical and functional outcomes. To our knowledge this report represents the initial study of in situ creation of experimental staghorn calculi and laparoscopic anatrophic nephrolithotomy performed completely intracorporeally in a chronic porcine model.
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PMID:Laparoscopic anatrophic nephrolithotomy: feasibility study in a chronic porcine model. 1463 29