Digital hypothermia inhibits early lamellar inflammatory signalling in the oligofructose laminitis model

Reasons for performing study: The pathophysiological events inhibited by prophylactic digital hypothermia that result in reduction of the severity of acute laminitis are unknown. Objectives: To determine if digital hypothermia inhibits lamellar inflammatory signalling during development of oligofructose (OF) induced laminitis. Methods: Fourteen Standardbred horses were given 10 g/kg bwt OF by nasogastric tube with one forelimb (CRYO) continuously cooled by immersion in ice and water and one forelimb (NON‐RX) at ambient temperature. Lamellae were harvested prior to the onset of lameness (24 h post OF administration, DEV group, n = 7) or at the onset of lameness (OG1 group, n = 7). Lamellar mRNA was purified and cDNA produced for real time‐quantitative PCR analysis of mRNA concentrations of cytokines (IL‐6, IL‐1β, IL‐10), chemokines (CXCL1, CXCL6, CXCL8/IL‐8, MCP‐1, MCP‐2), cell adhesion molecules (ICAM‐1, E‐selectin), COX‐2 and 3 housekeeping genes. Data were analysed (NON‐RX vs. CRYO, NON‐RX vs. archived control [CON, n = 7] lamellar tissue) using nonparametric tests. Results: Compared with CON, the OG1 NON‐RX had increased (P<0.05) lamellar mRNA concentrations of all measured mediators except IL‐10, IL‐1β and MCP‐1/2, whereas only CXCL8 was increased (P<0.05) in DEV NON‐RX. Within the OG1 group, CRYO limbs (compared with NON‐RX) had decreased (P<0.05) mRNA concentrations of the majority of measured inflammatory mediators (no change in MCP‐1 and IL‐10). Within the DEV group, mRNA concentrations of CXCL‐1, ICAM‐1, IL‐1β, CXCL8 and MCP‐2 were decreased (P<0.05) and the anti‐inflammatory cytokine IL‐10 was increased (compared with NON‐RX limbs; P<0.05). Conclusions: Digital hypothermia effectively blocked early lamellar inflammatory events likely to play an important role in lamellar injury including the expression of chemokines, proinflammatory cytokines, COX‐2 and endothelial adhesion molecules. Potential relevance: This study demonstrates a potential mechanism by which hypothermia reduces the severity of acute laminitis, and may help identify molecular targets for future laminitis intervention.     

Duration of thermal support for preventing hypothermia induced by anesthesia with medetomidine-midazolam-butorphanol in mice

Hypothermia during anesthetic events is a common adverse effect of anesthesia in laboratory animals. In particular, small rodents such as mice is susceptible to hypothermia during anesthetic events. Therefore, the animals will need additional thermal support by external heating devices during and after anesthesia. In general, the time of recovery from anesthesia is typically longer in case of injectable anesthesia rather than inhalant anesthesia. However, the durations of thermal support have been almost limited to 1 hr from administration of anesthesia in general. Our study objectives are two-fold: 1) to compare the levels of hypothermia induced by injectable anesthesia with medetomidine-midazolam-butorphanol (MMB) and inhalant anesthesia with isoflurane (ISO); 2) to find the adequate durations of thermal support for preventing hypothermia induced by their anesthesia in mice. Adult male ICR mice were anesthetized during 40 min without and with the thermal support for 1 (both anesthetic groups), 2, 3, and 5 hr (in MMB group). Without thermal support, the decrease of body temperature in MMB group were more severe than that in ISO group. The durations of thermal support completely prevented hypothermia at 5 hr-support in MMB group and that at 1 hr-support in ISO group. However, the other short durations did not prevent hypothermia at 1, 2 and 3 hr-support in MMB group. These results suggest that the mice should be received thermal support over 5 hr after injection of MMB anesthesia to prevent hypothermia.     

Hypothermia prevention in long-standing equine dental procedures

Hypothermia is a common, detrimental post-operative complication in man and veterinary medicine. Active warming strategies are paramount for prevention and treatment. Duration of operations, administered drugs and their adverse effects put horses undergoing procedures requiring long-standing sedation in danger of hypothermia. The aim of this study was to investigate whether an air warming device would be helpful to avoid severe hypothermia in adult horses. Twenty client-owned horses undergoing dental/sinusoidal procedures were divided into two equal groups. The treatment group was covered with a warming blanket connected to the warming device with the temperature set to 43°C. Horses in the control group were not blanketed. Temperature was measured at the time of first sedation (T0) and every hour throughout the length of the procedure. Use of the warming blanket was straightforward and caused no adverse reactions. The mean decrease in body core temperature in the treatment group was significantly less than the mean temperature decrease in the control group, beginning at the second hour of the procedure. No horse in the treatment group reached a body temperature below 36°C. Overall loss of temperature in the control group was more than double when compared with the treatment group (1.5°C and 0.7°C respectively). The use of an active air warming blanket in horses is an easy technique to prevent hypothermia in horses undergoing long-standing sedation procedures.     

IGF-1调控RBM3表达抑制低温应激诱导牦牛卵丘细胞凋亡

【目的】探索动物机体遭受低温应激及细胞冷冻过程中胰岛素样生长因子1(insulin-like growth factor, IGF-1)与RNA结合基序蛋白3(RNA-binding motif protein 3, RBM3)之间的作用关系,及IGF-1参与哺乳动物细胞抑制低温损伤的机制。【方法】体外培养牦牛卵丘细胞,采用实时荧光定量 PCR(quantitative real-time PCR, qRT-PCR)、蛋白免疫印迹(Western blot, WB )和免疫荧光技术检测不同浓度（0、50、100、200 ng·mL ^-1）IGF-1和低温应激（30℃、25℃）对RBM3表达影响。卵丘细胞经最佳浓度IGF-1(100 ng·mL ^-1)和对照组(0 IGF-1)作用30 h后,低温（30℃、25℃）应激8 h,比较RBM3表达水平。评估在低温应激组、100 ng·mL ^-1 IGF-1处理组和100 ng·mL ^-1 IGF-1+RBM3抑制剂处理组,卵丘细胞25℃应激8 h后凋亡水平差异,并从基因和蛋白水平检测3组卵丘细胞中凋亡相关基因Bax和Bcl-2的表达水平。【结果】 (1) IGF-1作用卵丘细胞后RBM3基因和蛋白的表达水平显著上升 (P<0.05),其在100 ng·mL ^-1 IGF-1处理组最高,免疫荧光检测显示100和200 ng·mL ^-1 IGF-1处理组卵丘细胞胞核和细胞质均可检测到RBM3,而0和50 ng·mL ^-1处理组,RBM3仅定位在细胞质。(2) 卵丘细胞经受低温应激时,RBM3的表达水平显著增加,但其在30℃和25℃应激处理组差异不显著;100 ng·mL ^-1 IGF-1作用卵丘细胞30 h后,其再次接受25℃、8 h低温应激,卵丘细胞中RBM3的表达水平显著高于低温应激前未经IGF-1处理卵丘细胞中RBM3的表达水平,且该处理组卵丘细胞胞质和胞核均可检测到RBM3。(3) 25℃应激后,100 ng·mL ^-1 IGF-1处理组卵丘细胞的凋亡率为(15.94±2.03)%,显著低于其在未经IGF-1处理组和100 ng·mL ^-1 IGF-1+RBM3抑制剂处理组中卵丘细胞的凋亡率,两者分别为(25.86±1.09)%和(20.14±2.65)%,在100 ng·mL ^-1 IGF-1处理组Bcl-2的表达水平显著高于其余两个处理组(P<0.05),而Bax的表达水平显著低于其余两个处理组 (P<0.05)。【结论】RBM3参与牦牛卵丘细胞低温应激调控,IGF-1可调控其在低温应激中的表达水平,从而降低低温诱导的卵丘细胞凋亡。本研究为揭示IGF-1和RBM3参与动物机体或细胞免受低温损伤的分子机制提供了关键信息,为体细胞和生殖细胞冷冻技术的提高提供了理论依据。     

Anaesthetic complications in pigs undergoing MRI guided convection enhanced drug delivery to the brain: a case series

ObservationsA total of 13 intracerebral infusions were performed at approximately 1 month intervals in three NIH miniature pigs over the age range of 31–59 weeks. Pigs received azaperone and ketamine premedication to allow venous cannulation and propofol induction of anaesthesia. Anaesthesia was maintained with isoflurane throughout cranial surgery and MRI scanning. Physiological monitoring during surgery consisted of blood pressure, pulse, temperature and oxygen saturation monitoring, ECG and capnography. Analgesia consisted of meloxicam and morphine. However, during MRI scanning blood pressure and ECG monitoring had to be discontinued. Anaesthetized pigs underwent intermittent intraputamenal convection enhanced delivery (CED) of gadolinium with real-time magnetic resonance imaging. Progressive tachycardia was consistently observed in all pigs during CED with a mean ± SD maximum increase of 41 ± 22 beats minute^?1 from a baseline heart rate of 96 ± 9 minute^?1. The heart rate remained elevated until recovery. A mean reduction in body temperature of 2.8 ± 0.6 °C from the start of anaesthesia was also observed during the period of MRI scanning. All pigs recovered from anaesthesia smoothly and heart rates returned to normal during the recovery period.ConclusionsHypothermia is common in pigs undergoing this sedation and anaesthesia protocol. Convection enhanced delivery of drugs in healthy anaesthetized pigs may result in tachycardia.     

贝类保鲜技术研究进展

贝类产品中蛋白质、水分、脂肪含量丰富,容易引起微生物繁殖导致腐败变质,因此贝类防腐保鲜技术是重要研究方向。从贝类在保鲜过程中的物理、生化、感官的变化入手,综述了低温保鲜、气调保鲜、辐照保鲜、生物保鲜剂保鲜4 种贝类储藏保鲜技术,对各保鲜技术的优缺点进行对比分析,以便在实际应用中对于不同外界条件选择最合适的保鲜方法。指出当前国内贝类在保鲜过程中的问题,并对贝类保鲜发展前景进行展望。