Effect of thyroglobulin gene polymorphisms on growth, carcass composition and meat quality traits in Chinese beef cattle.

The thyroglobulin (TG) gene has been studied as an important gene related to fat deposition, since not only does TG gene locate in a quantitative trait locus with an effect on fat deposition, but also it encodes the precursor of thyroid hormones which have crucial biological functions in energy metabolism. In the present study, we identified four novel SNPs at the 5' flanking region of the bovine TG gene. Association analysis indicated that the G275A, G277C, G280A and C281G SNPs were significantly associated with average daily gain (ADG, P < 0.01 for G275A and G277C, P < 0.05 for G280A and C281G). Five haplotypes for the 4 SNPs were constructed and their effects on growth, carcass composition and meat quality traits were evaluated. The results showed no significant effect of haplotype on ADG. Meanwhile, no significant association was found between 4 SNPs and other growth, carcass composition and meat quality traits including intramuscular fat. Bioinformatics analysis showed that 4 SNPs may results in potential transcription factor binding site changes. Results of this study suggest that TG gene-specific SNPs may be a useful marker for growth traits in marker assisted selection programs in beef cattle.

Hyperoxia management during deep hypothermia for cerebral protection in circulatory arrest rabbit model.

As a brain protection strategy, antegrade selective cerebral perfusion (ASCP) is widely used in thoracic aorta surgery with deep hypothermic circulatory arrest (DHCA), yet the oxygen management for ASCP has never been standardized. The aim of this study was to investigate the possible neuroprotective effects of hyperoxia management during deep hyperthermia for ASCP combined with DHCA in a rabbit model. Rabbits were assigned into four groups: sham group, without cardiopulmonary bypass (CPB); DHCA group, DHCA for 80 minutes; ASCP group, ASCP combined with DHCA; and SH group, hyperoxia management combined with ASCP and DHCA. Hyperoxia management was performed when the nasopharyngeal temperature was below 22°C. Deep hypothermic circulatory arrest was initiated when nasopharyngeal temperature reached 16-18°C. Blood samples were withdrawn to determine blood gas indexes and neurobiochemical markers of damage, and brain tissues were stored for biochemical analysis. Cerebral oxygen balance was performed better in the SH group compared with the DHCA group and the ASCP group. Hyperoxia management did not increase lipid peroxidation with lower malondialdehyde levels in the SH group compared with the DHCA group and the ASCP group (p < 0.05). S100 calcium binding protein B in the SH group was lower compared with the DHCA group and the ASCP group (p < 0.05). There was no significant difference of neuron-specific enolase in the SH group compared with the sham group. Hyperoxia management during deep hypothermia provided substantial dissolved oxygen and demonstrated better cerebral protection over normoxia management.

Effects of pulsatile and nonpulsatile perfusion on cerebral regional oxygen saturation and endothelin-1 in tetralogy of fallot infants.

Although benefits of pulsatile flow during cardiopulmonary bypass (CPB) in pediatric heart surgery remain controversial and nonpulsatile CPB is still widely used in clinical cardiac surgery, pulsatile CPB must be reconsidered due to its physiologic features. In this study, we aimed to evaluate the effects of pulsatile perfusion (PP) and nonpulsatile perfusion (NP) on cerebral regional oxygen saturation (rSO2) and endothelin-1 (ET-1) in pediatric tetralogy of Fallot (TOF) patients undergoing open heart surgery with CPB. Forty pediatric patients were randomly divided into the PP group (n = 20) and the NP group (n = 20). Pulsatile patients used a modified roller pump during the cross-clamp period in CPB, while NP patients used a roller pump with continuous flat flow perfusion. The subjects were monitored for rSO2 from the beginning of the operation until 6 h after returning to the intensive care unit (ICU). We also monitored the hemodynamic status and ET-1 concentration and plasma free hemoglobin (PFH) in blood samples of all patients over time. Effective PP was monitored in PP patients, and pulse pressure was significantly higher in the PP group than in the NP group (P < 0.01). rSO2 of the PP group was higher than that of the NP group (P < 0.01) during the cross-clamp period, and this advantage of PP would be maintained until 2 h after patients returned to the ICU (P < 0.05). ET-1 level in blood samples was lower at clamping off and CPB weaning and early ICU period in the PP group than in the NP group (P < 0.01), and ET-1 concentration remained at a normal level after patients were transferred to the ICU 24 h in all patients. PFH levels in the PP group at pre-clamp off and CPB weaned off were higher than those of the NP group (P < 0.05) in these cyanotic patients. PP can increase rSO2 and improve microcirculation during cross-clamping period in TOF pediatric patients, while PP resulted in more severe hemolysis in these cyanotic patients than NP.

[Clinical application of cerebral oxygenation monitoring during aortic aneurysm operation].

OBJECTIVE: To analyze the correlation between cerebral oxygenation and cerebral complications after aortic aneurysm operation and to evaluate the protective effects of DHCA and/or ASCP during aortic aneurysm operation. METHODS: Thirty patients with aortic aneurysm, 24 with Stanford type A dissection, 4 with Stanford type B dissection, 1 with degenerative aneurysm in ascending and arch aorta, and 1 with false aneurysm in thoraco-abdominal aorta, 23 males and 7 females, aged 44 +/- 12, underwent aorta operation with circulatory arrest were alternatively allocated to two groups: 22 patients underwent aortic arch replacement under deep hypothermic circulatory arrest (DHCA) plus antegrade selective cerebral perfusion (ASCP), and 8 patients underwent descending thoracic aorta replacement under DHCA only. There was no significant difference in the lowest core temperature, hematocrit at lowest core temperature, and velocity of rewarming between these 2 groups. Near-infrared spectroscopy (NIRS) was used to continuously monitor the cerebral tissue oxygenation index (TOI) percutaneously. RESULTS: The mean circulatory arrest time in the DHCA + ASCP group was 23.25 min, significantly longer than that of the DHCA group (16.67 min, P = 0.022). Cerebral complication occurred in 8 patients after aortic operation (complication group). The baseline TOI of the complication group was 70% +/- 5%, and the maximum decrease in TOI was 58% +/- 8%; and the baseline TOI of the non-complication group was 69% +/- 8%, and the maximum decrease in TOI was 55% +/- 8%; however, there were no significant differences between these 2 groups (both P > 0.05). The TOI decrease was more significant in the DHCA group than in the DHCA + ASCP group. During circulatory arrest, the levels of TOI were higher than the baseline level all along in the ASCP group and were lower than the baseline level 3 to 10 minutes after arrest in the DHCA group. The duration of TOI less than the baseline level in the DHCA group was significantly longer than that in the ASCP group. CONCLUSION: Mild decrease of TOI is not significantly correlated to the occurrence of complication. DHCA + ASCP is more effective in brain protection compared with only DHCA.

Effect of potassium-channel openers on the release of endothelium-derived hyperpolarizing factor in porcine coronary arteries stored in cold hyperkalemic solution.

Hyperkalemic solution is widely used to protect the myocardium during open-heart surgery or to preserve donor hearts during heart or heart/lung transplants. The inhibitory effects of hvperkalemic solution on the release of endothelium-derived hyperpolarizing factor (EDHF) of coronary arteries following deep hypothermic storage (4 degrees C) has been well studied. However, it has not been established whether potassium channel openers have protective effects on the coronary endothelial function after cold storage. This study was designed to examine this. Porcine coronary artery rings were studied in organ baths. Relaxation in response to the EDHF stimulus A23187 (nonreceptor-mediated stimulus calcium ionophore) in thromboxane A2 mimetic U46619 (30 nmol/L)-induced precontraction after incubation with hyperkalemic solution (20 mmol/L) with nicorandil (10 micromol/L) (either at 37 degrees C in the oxygenated organ chamber or at 4 degrees C in a refrigerator for 6 h) was compared with the control. There was significant difference between hyperkalemia group and hyperkalemia with nicorandil group under normothermia (p = .04). The difference was significant in the same solution between normothermia and hypothermia. After incubation in hyperkalemic solution without or with nicorandil, the A23187-induced relaxation was 32.8% +/- 9.1% and 72.6% +/- 16.9%, respectively (N = 8, p < .01). Potassium channel opener can attenuate the inhibitory effect of hyperkalemic solution on the release of EDHF after cold storage.