Effect of moderate cooling on contractile responses in mouse vas deferens and its relation to calcium

Isolated mouse vas deferens preparations were used to study the effect of temperature on noradrenaline-induced contractions. Preparations were suspended in the organ bath containing Krebs-Henseleit solution for isometric tension recording. Contractile responses to noradrenaline were investigated in the mouse vas deferens after moderate cooling from 37 to 26 or 22° C. A significant increase of the phasic contractions to noradrenaline was observed at 26 or 22°C compared with responses obtained at 37° C (about 12.3 and 35.6% increase at 26 and 22° C, respectively). The secondary noradrenaline-induced sustained contraction was also significantly enhanced after moderate cooling to 26° C. The potentiation of noradrenaline-induced contraction at 26° C remained in a Ca²⁺-free EGTA (1 mM)-containing solution. However, sustained contraction was suppressed after removal of the calcium from the medium at 37 and 26°C. Contraction to caffeine was significantly enhanced at 22° C compared with 37°C. By contrast, barium chloride-induced contraction of the vas deferens was markedly decreased after moderate cooling to 22° C. In the presence of ouabain (0.1 mM), the noradrenaline-induced peak contraction was significantly increased at 37°C. However, potentiation of the noradrenaline response at 22° C was unaffected by the Na⁺/K⁺ pump inhibitor. Noradrenaline-induced peak contractions were depressed in the presence of vanadate (1 mM) and cyclopiazonic acid (10 M), two Ca²⁺-ATPase inhibitors, at 37° C and also at 22° C. These results suggest that temperature-induced hyperreactivity is partly due to an increase of the amount of calcium released from intracellular stores. The inhibition of the Na⁺/K⁺ pump due to cooling may participate in this effect whereas Ca²⁺-ATPase inhibition does not seem to be involved.     

菜籽油中有害物——芥酸的提取

目的：为了研究提取菜籽油中有害物芥酸的较好方法。方珐：采用冷结晶法提取并酸，并与铅盐法提取芥酸作了比较。结果：冷结晶法简单方便．总产率较高。结论：冷结晶法效果更好。     

板式换热器在不同制冷系统中的应用

板式换热器在制冷系统中得到了广泛的应用，它具有高效、紧凑等优点。本文着重介绍在氨、氟利昂22、氟利昂13的各种制冷系统中，可能产生板式换热器不能正常工作的情况及其如何采取措施防止上述现象的发生。     

Cooling abolishes neuronal network synchronization in rat hippocampal slices

PURPOSE: We sought to determine whether cooling brain tissue from 34 to 21 degrees C could abolish tetany-induced neuronal network synchronization (gamma oscillations) without blocking normal synaptic transmission. METHODS: Intracellular and extracellular electrodes recorded activity in transverse hippocampal slices (450-500 microm) from Sprague-Dawley male rats, maintained in an air-fluid interface chamber. Gamma oscillations were evoked by afferent stimulation at 100 Hz for 200 ms. Baseline temperature in the recording chamber was 34 degrees C, reduced to 21 degrees C within 20 min. RESULTS: Suprathreshold tetanic stimuli evoked membrane potential oscillations in the 40-Hz frequency range (n = 21). Gamma oscillations induced by tetanic stimulation were blocked by bicuculline, a gamma-aminobutyric acid (GABA)A-receptor antagonist. Cooling from 34 to 21 degrees C reversibly abolished gamma oscillations in all slices tested. Short, low-frequency discharges persisted after cooling in six of 14 slices. Single-pulse-evoked potentials, however, were preserved after cooling in all cases. Latency between stimulus and onset of gamma oscillation was increased with cooling. Frequency of oscillation was correlated with chamber cooling temperature (r = 0.77). Tetanic stimulation at high intensity elicited not only gamma oscillation, but also epileptiform bursts. Cooling dramatically attenuated gamma oscillation and abolished epileptiform bursts in a reversible manner. CONCLUSIONS: Tetany-induced neuronal network synchronization by GABAA-sensitive gamma oscillations is abolished reversibly by cooling to temperatures that do not block excitatory synaptic transmission. Cooling also suppresses transition from gamma oscillation to ictal bursting at higher stimulus intensities. These findings suggest that cooling may disrupt network synchrony necessary for epileptiform activity.     

Cancellation of visuoparietal lesion-induced spatial neglect

In humans lesions of right visuoparietal cortex induce a neglect of the contralesional visual field that is characterized in its mild form by inattentiveness to objects and events and, in its more severe form, by a condition that has many features that are indistinguishable from blindness. Here we show that spatial neglect can be induced in cats by lesions of posterior and inferior visuoparietal cortex, and that the lesion-induced neglect can be cancelled by cooling deactivation of the same region in the opposite hemisphere. Electronic Publication     

Application of Newton's law to body cooling

Summary Newton's law of cooling was used to analyze the fall in rectal temperature post mortem in 55 cases during refrigeration in a mortuary. As with solids of low thermal conductivity, there was an initial curvilinearity to the semilog plot lasting 1 to 11 hours (related to pelvic circumference) while the proper internal temperature distribution was becoming established. Thereafter there was a linear trend representing a constant percent cooling rater ₁ which lasted up to 24 hours for adults. This was followed by a less steep trend of cooling rater ₂, which was 37% less thanr ₁. This diminution in cooling rate occurred when the rectal temperature fell below 10°C and was ascribed to a reduction in the thermal diffusivity of fat.r ₁ had the highest correlation with pelvic circumference. For the nude body in still airr ₁=15.6% to 18.4% (T _r –T _a )/hour for children, 3.8% to 9.4% for adults. Wind increasedr ₁; the decrease due to clothing was questionable because of the paucity of cases. G. W. Molnar, Ph. D., formerly at the U.S. Army Medical Research Laboratory, Ft. Knox, Ky. H. J. Hurley, Jr., M. D., formerly Captain, M. C., U.S. Army Medical Research Laboratory, Ft. Knox, Ky.     

First aid improves clinical outcomes in burn injuries: Evidence from a cohort study of 4918 patients

Background

Animal studies indicate treating burn injuries with running water (first aid) for 20 min up to 3 h post-burn reduces healing time and scarring. There is a lack of human data to support such a recommendation. The purpose of this cohort study was to assess the effect of first aid on clinical outcomes.

Passive nondestructive burnup monitoring of MNSR irradiated fuel by measuring photoneutrons produced within fission products

A passive nondestructive method for monitoring of Syrian miniature neutron source reactor (MNSR) fuel burnup is introduced. The inner irradiation site design inside the Be reflector was exploited to measure the generated photoneutrons induced by fission products hard gamma radiation in the subcritical state. The photoneutron flux was measured using gold foils as a function of cooling time and operation power. For cooling time ranges between 10 and 25 d, experiments show that ¹⁴⁰Ba is the extremely dominating inducer of photoneutrons and the measured flux is proportional to the accumulated ¹⁴⁰Ba. This result forms a new method base for MNSR fuel burnup monitoring. It might be used also as a safeguards technique to check the operator declared information.     

Therapeutic hypothermia for neonatal encephalopathy: a UK survey of opinion, practice and neuro-investigation at the end of 2007

Background: The 2007 Cochrane review of therapeutic hypothermia for neonatal encephalopathy (NE) indicates a significant reduction in adverse outcome. UK National Institute for Clinical Excellence guidelines are awaited.
Objective: To benchmark current opinion and practice to inform future strategies for optimal knowledge transfer for therapeutic hypothermia.
Methods: A web based questionnaire (30 sections related to opinion and practice of management of NE) sent to the clinical leads of Level I, II and III neonatal units throughout the UK in November/December 2007.
Results: One hundred and twenty-five (out of 195) UK neonatal units responded (response rate 66%). Ten percent, 37.5% and 51.5% responses were from level I, II and III units respectively. Twenty eight percent of all units provided therapeutic hypothermia locally (52% of level III units), however 80% of responders would offer therapeutic hypothermia if there was the facility. Overall, 57% of responders considered therapeutic hypothermia effective or very effective – similar for all unit levels; 43% considered more data are required. Regional availability of therapeutic hypothermia exists in 55% of units and 41% of units offer transfer to a regional centre for therapeutic hypothermia.
Conclusion: In the UK in 2007, access to therapeutic hypothermia was widespread although not universal. More than half of responders considered therapeutic hypothermia effective. Fifty-five percent of perinatal networks have the facility to offer therapeutic hypothermia. The involvement of national bodies may be necessary to ensure the adoption of therapeutic hypothermia according to defined protocols and standards; registration is important and will help ensure universal neurodevelopmental follow up.     

小鼠精原干细胞冷冻保存

目的 探索小鼠精原干细胞(SSCs)冷冻保存方法 以及解冻后体外快速增殖的条件. 方法 实验以6d龄雄性昆明小白鼠为材料,两步酶消化法分离小鼠睾丸生殖细胞,Percoll非连续密度梯度离心法富集小鼠精原干细胞,随后加入不同的冷冻液以及采用不同的降温速率冷冻小鼠精原干细胞.以MEMα为基本培养基,加入10%胎牛血清和100μg/L的胶质细胞源性神经营养因子, WST-8比色法分析培养SSCs 复苏后的增殖率,运用碱性磷酸酶细胞化学染色和RT-PCR技术,对培养的SSCs进行鉴定. 结果 冷冻液中添加10%二甲基亚砜、10%胎牛血清、0.07mol/L蔗糖时,以1℃/min程控降温方式冷冻小鼠SSCs,细胞解冻后活率最高,达84%以上;采用非程控降温方式冻存SSCs,尽管细胞解冻后活率相对于程控降温方式略低,但具有方法 简单、易于操作、无需昂贵仪器的优点,复苏后SSCs贴壁时间为8～12h,24h可见细胞分裂,48h细胞出现迅速增殖,96h可见较多含20～25细胞的细胞团,此时精原干细胞增殖近5倍. 结论 本实验所用培养条件,可以使经长期冷冻的SSCs短期快速增殖.