Regenerating endothelial cells express insulin-like growth factor-I immunoreactivity after arterial injury

Summary In the present study the expression of insulin-like growth factor I (IGF-I; somatomedin C) immunoreactivity was examined in endothelial cells during repair after injury to the intima in the femoral artery of adult rats. Two types of injury were examined: (1) endothelial denudation induced by the use of a catheter, and (2) vessel compression by short-term ligation. In untreated rats, arterial endothelial cells showed no or, only infrequently, low IGF-I immunoreactivity in their cytoplasm. Endothelial cells at the border to the denuded area showed increased IGF-I immunoreactivity one day after injury to the intima of the femoral artery. Thrombocytes and fibrin deposits as well as vital endothelial cells, covered by clots, were immunonegative. The maximal intensity of IGF-I immunoreactivity was reached within 3 days after insult. The IGF-I immunoreactivity in the endothelial cells remained elevated for at least 4 weeks, compared to the controls. Intimai thickenings appeared within a week after injury and many cells in these thickenings showed intense IGF-I immunoreactivity as did the covering endothelial cells. Smooth muscle cells in the media were generally immunonegative during control conditions and after endothelial denudation. Spontaneously hypertensive rats (SHR) showed, similarly to their matched controls (WKY), approximately the same patterns of IGF-I immunoreactivity in their endothelial cells both under normal conditions and after injury. It is concluded that IGF-I is likely to be involved in the repair of the intima in injured arteries.     

Ice formation and tissue response in apple twigs

Abstract. The response of apple twig tissue to a freezing stress was examined using a combination of low temperature scanning electron microscopy and freeze substitution techniques. Bark and wood tissues responded differently. In the bark, large extracellular ice crystals were observed in the cortex. The adjacent cortical cells collapsed and a large reduction in cell volume was observed. The extent of cell collapse throughout the bark was not uniform. Cells in the periderm, phloem and cambium exhibited little change in cell volume compared to cortical cells. Large extracellular ice crystals were not observed in the xylem or pith tissues. The xylem ray parenchyma and pith cells did not collapse in response to a freezing stress, but retained their original shape. The pattern of ice formation and cell response was not observed to change with season or the level of cold acclimation. This study supported the concept that bark and xylem tissues exhibit contrasting freezing behaviour. The observations were consistent with the idea that water in bark freezes extracellularly while water in xylem ray parenchyma and pith cells may supercool to temperatures approaching –40 °C prior to freezing intracellularly.     

Freeze/thaw-induced destabilization of the plasma membrane and the effects of cold acclimation

Disruption of the plasma membrane is a primary cause of freezing injury. In this review, the mechanisms of injury resulting from freeze-induced cell dehydration are presented, including destabilization of the plasma membrane resulting from (a) freeze/thaw-induced osmotic excursions and (b) lyotropic phase transitions in the plasma membrane lipids. Cold acclimation dramatically alters the behavior of the plasma membrane during a freeze/thaw cycle—increasing the tolerance to osmotic excursions and decreasing the propensity for dehydration-induced lamellar to hexagonal-II phase transitions. Evidence for a casual relationship between the increased cryostability of the plasma membrane and alterations in the lipid composition is reviewed.     

消炎痛致胃粘膜损伤时胃组织胺含量变化及甲氰咪胍的影响

消炎痛可引起小鼠胃粘膜损伤,在一定剂量范围内,其剂量和胃粘膜损伤程度之间有明显的量效关系。在引起胃粘膜损伤时,胃组织胺含量相应增加,大剂量重度损伤时尤为明显。预先用甲氰咪胍灌胃,可明显减轻损伤并降低组织胺含量。提示组织胺参与消炎痛致胃粘膜损伤过程并对损伤产生一定影响。     

Na+-H+ exchange inhibition at reperfusion is cardioprotective during myocardial ischemia-reperfusion; 31P NMR studies

To help resolve the controversy as to whether or not Na⁺-H⁺ exchange is functioning during reperfusion of the ischemic myocardium we assessed the effects of dimethylamiloride (DMA, an amiloride analogue possessing selectivity for inhibition of the Na⁺-H⁺ exchanger) on cardiac function and intracellular pH during ischemia-reperfusion. Studies were performed in the presence of bicarbonate (modified Krebs-Henseleit buffer) or in the nominal absence of bicarbonate (HEPES buffer) in order to determine if similar cardioprotection and effects on intracellular pH were observed in the presence and absence of bicarbonate dependent transport processes. Isovolumic rat hearts were perfused in the Langendorff mode at a constant pressure of 80 mm Hg and subjected to 28 min total global ischemia at 37°C. Intracellular pH was determined from the pH dependent shift of the inorganic phosphate peak in ³¹P nuclear magnetic resonance spectra. DMA (20 µM) was infused for either 2.5 min before ischemia, for the initial 5 min of reperfusion, or at both time intervals. DMA had no effect on the intracellular pH during ischemia. Intracellular pH returned to pre-ischemic levels within 2.5 min of reperfusion in bicarbonate buffer. This normalization of pH was slower in HEPES perfusate. In both bicarbonate and HEPES perfused hearts all drug dosing regimens caused a significant increase in the recovery of mechanical function after reperfusion and slowed the recovery of intracellular pH during reperfusion. These results suggest that the Na⁺-H⁺ exchanger is activated during reperfusion of the ischemic myocardium, that this activation of the exchanger contributes to ischemia-reperfusion induced cardiac dysfunction and that administration of an inhibitor of Na⁺-H⁺ exchange at reperfusion significantly attenuates the deleterious effects of exchanger activation.     

HRR、PLR与中重度颅脑损伤患者短期死亡的关系研究

摘要 目的：探讨血红蛋白/红细胞分布宽度比值（HRR）、血小板/淋巴细胞比值（PLR）与中重度颅脑损伤（TBI）患者短期死亡的关系。方法：回顾性收集2019年9月～2021年9月徐州医科大学附属医院收治的162例中重度TBI患者的病历资料，根据患者入院30d内生存状态分为死亡组和存活组。计算HRR和PLR，采用多因素Logistic回归分析中重度TBI患者短期死亡的影响因素，受试者工作特征（ROC）曲线分析格拉斯哥昏迷量表（GCS）评分联合HRR、PLR对中重度TBI患者短期死亡的预测价值。结果：162例中重度TBI患者入院30 d内死亡率为35.80%（58/162）。与存活组比较，死亡组HRR降低，PLR升高（P＜0.05）。多因素Logistic回归分析显示，GCS评分＜9分、瞳孔散大、脑疝和HRR降低、PLR升高为中重度TBI患者短期死亡的独立危险因素（P＜0.05）。ROC曲线分析显示，HRR、PLR联合GCS评分预测中重度TBI患者短期死亡的曲线下面积最大，为0.924。结论：HRR降低和PLR升高与中重度TBI患者短期死亡相关，可能成为中重度TBI患者短期死亡的辅助预测指标，在GCS评分基础上联合HRR、PLR能提升对中重度TBI患者短期死亡的预测价值。     

Assessment of fetal canine cardiac myocyte survival in a dual‐side flow bioreactor with modeled hypoxia/reperfusion injury

The present study introduces a new experimental model of hypoxia/reperfusion injury using a newly developed bioreactor system. The injury is introduced and kept localized via fluid dynamic manipulation. Using low Reynolds number fluid flow, regions of the culture can be injured while maintaining physiological conditions in the remaining culture. This approach enables both normal and injured cells within the same monolayer to be investigated side‐by‐side. The current study evaluated the ability of the model to induce localized reperfusion injury in a monolayer of fetal canine cardiomyocytes (FCCs). Significant apoptosis was found in the hypoxia/reperfusion‐injured but not normal‐flow regions of the myocyte cultures. The model holds the potential to help elucidate the fundamental mechanisms of hypoxic/reperfusion insults in myocardium. Biotechnol. Bioeng. 2009;103: 199–206. © 2008 Wiley Periodicals, Inc.     

Seasonal dynamics of economic injury levels for Tetranychus urticae Koch (Acari, Tetranychidae) on Cucumis sativus L.

Abstract:  Economic injury level (EIL) for Tetranychus urticae Koch on glasshouse cucumbers was established in two ways: EILs based on the number of T. urticae introduced to cucumber early in the growing season and EILs based on mite density and feeding durations (i.e. cumulative mite-days) in each of four growing seasons. The relationship between yield loss and T. urticae infestation level varied among four growing seasons. One mite introduced to cucumber early in the growing season could reduce the cucumber yield by 5.03, 3.20, 1.12 and 2.86 g per plant in spring, summer, autumn and winter, respectively. One mite-day (i.e. one mite feeding in a day) reduced cucumber yield by 0.0123, 0.0074, 0.0035 and 0.0073 g per plant in spring, summer, autumn and winter, respectively. When the seasonal dynamics of market values of cucumber was considered, EILs were the lowest in spring and the highest in autumn. When four seasonal data were combined, EILs can be calculated as EIL = C /(0.00276 ×  K ) for the number of T. urticae introduced early in the growing season and EIL = C /(6.8342 × 10⁻⁶ ×  K ) for cumulative mite-days, where K is efficacy of control measure and C the management cost. This study demonstrated the seasonal dynamics of EILs for T. urticae on glasshouse cucumbers, suggesting that decision making for T. urticae management on cucumber needs to be seasonally different under the glasshouse condition.     

Normalising surface EMG of ten upper-extremity muscles in handcycling: Manual resistance vs. sport-specific MVICs

Muscular activity in terms of surface electromyography (sEMG) is usually normalised to maximal voluntary isometric contractions (MVICs). This study aims to compare two different MVIC-modes in handcycling and examine the effect of moving average window-size. Twelve able-bodied male competitive triathletes performed ten MVICs against manual resistance and four sport-specific trials against fixed cranks. sEMG of ten muscles [M. trapezius (TD); M. pectoralis major (PM); M. deltoideus, Pars clavicularis (DA); M. deltoideus, Pars spinalis (DP); M. biceps brachii (BB); M. triceps brachii (TB); forearm flexors (FC); forearm extensors (EC); M. latissimus dorsi (LD) and M. rectus abdominis (RA)] was recorded and filtered using moving average window-sizes of 150, 200, 250 and 300 ms. Sport-specific MVICs were higher compared to manual resistance for TB, DA, DP and LD, whereas FC, TD, BB and RA demonstrated lower values. PM and EC demonstrated no significant difference between MVIC-modes. Moving average window-size had no effect on MVIC outcomes. MVIC-mode should be taken into account when normalised sEMG data are illustrated in handcycling. Sport-specific MVICs seem to be suitable for some muscles (TB, DA, DP and LD), but should be augmented by MVICs against manual/mechanical resistance for FC, TD, BB and RA.