Is ivabradine suitable to control undesirable tachycardia induced by dobutamine in cardiogenic shock treatment?

Inotropic treatment remains the cornerstone for cardiogenic shock, an emergency that requires immediate resuscitative therapy before shock irreversibly damages vital organs. Although the sympathomimetic drug dobutamine is the most widely-used inotropic drug worldwide, it has several side effects including sinus tachycardia. Dobutamine partly restores systolic heart failure (HF); however, it increases the heart rate (HR) which counterbalances the beneficial effects. Ivabradine, a new selective I_f inhibitor, provides specific HR reduction and is indicated in stable coronary artery disease and in stable chronic HF with left ventricular dysfunction. Despite scarce data indicating beneficial effects of ivabradine in sinus tachycardia in various clinical settings, this drug remains contraindicated in acute HF. We propose that ivabradine could help to prevent the dobutamine-induced side effects, and that their combination in clinical practice could lead to pure inotropic effects, useful for the management of cardiogenic shock.     

超极化激活环核苷酸门控阳离子通道亚型在大鼠脊髓背角浅层的特异性表达

目的:探讨超极化激活环核苷酸门控阳离子通道(hyperpolarization-activated cyclic nucleotide-gated cation channels,HCN通道)4种亚型在大鼠脊髓背角浅层的表达与分布特点。方法:选取3～5周龄SD大鼠,雌雄不拘,制作L4～L5段脊髓横切片,应用免疫组织化学技术及激光共聚焦成像技术,观察HCN通道的4种亚型在脊髓背角浅层神经元、胶质细胞及神经元亚细胞结构中的分布。结果:HCN通道不同亚型在正常SD大鼠脊髓背角中的表达和分布具有特异性:(1)HCN1主要与神经元标志物[神经元核抗原(neuronal nuclei,NeuN)]和星形胶质细胞标志物[胶质细胞原纤维酸性蛋白(glial fibrillary acidic protein,GFAP)]共存,HCN2和HCN3主要与NeuN共定位;(2)HCN2主要与肽能初级传入神经末梢标志物[降钙素基因相关肽(calcitonin gene-related peptide,CGRP)]共存,HCN4主要与非肽能初级传入神经末梢标志物[异凝集素B4(isolectin B4,IB4)...     

Intestinal necrosis related to administration of cation exchange resin without sorbitol: A retrospective analysis of 61 patients with end‐stage renal diseases

Intestinal necrosis associated with cation exchange resin (CER) is considered related to sorbitol, but it has been reported even in patients receiving CER alone. This study was performed to identify the risk factors of CER‐related intestinal necrosis. The pathological database of 61 end‐stage renal disease patients with surgical intervention for intestinal perforation was reviewed. The correlations between CER treatment and clinicopathological factors were studied among three groups: (i) patients administered CER and with CER at the perforation site (n = 23), (ii) patients administered CER with undetected CER at the perforation site (n = 12) and (iii) patients not administered CER (n = 26). The majority of the perforation site in group 1 was in the sigmoid colon (82.6%) with significantly higher average age and more frequent CER adhesion rates to the mucosa around the perforation site than group 2. The laxative administration rate in group 1 was significantly higher than group 3 and tended to be higher than group 2. The incidence of CER‐related intestinal necrosis was estimated at 0.57%. CER should be used with extreme caution in elderly patients with passage disturbance.     

IL-13 基因多态性与血清IL-13及嗜酸细胞阳离子蛋白水平的关系

目的　探讨 IL- 13基因多态性与血清 IL- 13及嗜酸细胞阳离子蛋白 (eosinophil cationprotein,ECP)水平的关系及 IL- 13基因多态性在儿童哮喘发病机理中可能的作用。方法　应用限制性内切酶片段长度多态位点法检测 96例哮喘患儿及 5 3名正常对照组儿童 IL - 13内含子 3+192 3位点 C/ T基因多态性 ,并应用 EL ISA法测定血清 IL- 13水平 ,运用荧光酶联免疫法测定血清 ECP水平。结果　哮喘组患儿 IL - 13内含子 3+192 3位点 TT、TC基因型频率分布高于正常对照组 (P<0 .0 5 ) ,且 TT、TC基因型患儿血清 IL- 13、ECP水平较 CC基因型明显升高 (P<0 .0 1)。结论　 IL- 13基因多态性与血清 IL- 13及 ECP水平关系密切 ,提示 IL - 13基因多态性在儿童哮喘发病机理中可能起重要的作用。     

Functional study of the Nha1p C-terminus: involvement in cell response to changes in external osmolarity

Saccharomyces cerevisiae uses different mechanisms to adapt to changes in environmental osmolarity. Upon hyperosmotic shock, cells first mobilize a rapid rescue system that prevents excessive loss of ions and water; then in the adaptation period they accumulate a compatible solute (glycerol). When subjected to hypoosmotic shock, they rapidly release intracellular stocks of glycerol to reduce intracellular osmolarity and prevent bursting. The plasma membrane Nha1 alkali metal cation/H⁺ antiporter is not important in helping the cells to survive a sudden drop in external osmolarity, but is involved in the cell response to hyperosmotic shock. For this role, its long hydrophilic C-terminus is indispensable. The capacity of the Nha1 antiporter to transport potassium is regulated by Hog1 kinase. Upon sorbitol-mediated stress, the Nha1p potassium export activity decreases in order to maintain a higher intracellular concentration of solutes. The C-terminal-less Nha1 version is not inactivated and its potassium efflux activity renders cells very sensitive to hyperosmotic shock. Taken together, our results suggest an important role of Nha1p and its C-terminus in the immediate response to hyperosmotic shock as part of the rapid rescue mechanism.     

铜,锌对培养心肌细胞缺氧／再给氧损伤的影响

本文观察了不同浓度的铜、锌对培养乳鼠心肌细胞缺氧/再给氧损伤后超氧歧化酶(superoxid dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-px)活性和脂质过氧化(lipid peroxidation,LPO)代谢产物丙二醛(malondialodehyde,MDA)含量改变,以及乳酸脱氢酶(lactate dehydrogenase,LDH)释放的影响。结果表明:缺氧/再给氧后,心肌细胞SOD活性降低,GSH-px活性和MDA含量增高,LDH释放增加。铜、锌均能不同程度地提高SOD活性,但铜的作用强于锌。锌、铜均可降低LDH的释放,但锌的作用强于铜,锌、铜浓度过高反而增加LDH的释放。此外,铜使GSH-px活性明显升高,并显著降低MDA含量。     

托吡酯及丙戊酸钠对癫痫患儿血清六种常微量元素的影响

目的观察托吡酯及丙戊酸钠对癫痫患儿血清六种常微量元素的影响。方法选取80例癫痫患儿,40例予托吡酯(TPM)单药治疗,40例予丙戊酸钠(VPA)单药治疗,选取40例健康儿童作正常对照。所有儿童于治疗前及治疗6个月后行锌、铁、铜、钙、镁及铅检测。结果癫痫患儿治疗前血清钙、铁及锌分别为(1.45±0.40)mmol/L、(7.25±2.16)mmol/L、(69.88±10.99)μmol/L,明显低于对照组[分别为(1.66±0.45)mmol/L、(8.26±2.65)mmol/L、(78.24±12.44)μmol/L],差异有统计学意义(P0.05),铜、镁及铅含量与对照组比较,差异无统计学意义(P0.05)。VPA组与TPM组治疗前铜、锌、镁、钙、铁及铅含量比较,差异无统计学意义(P0.05)。2组治疗后各种元素含量比较,差异无统计学意义(P0.05)。癫痫患儿治疗前后各种元素含量比较,差异无统计学意义(P0.05)。结论癫痫患儿血清锌、钙及铁含量降低。VPA及TPM治疗对癫痫患儿血清锌、铁、铜、钙、镁、铅含量无明显影响。     

Evidence that preimmunization with a heat-killed preparation of Mycobacterium vaccae reduces corticotropin-releasing hormone mRNA expression in the extended amygdala in a fear-potentiated startle paradigm

Posttraumatic stress disorder (PTSD) is a trauma and stressor-related disorder that is characterized by dysregulation of glucocorticoid signaling, chronic low-grade inflammation, and impairment in the ability to extinguish learned fear. Corticotropin-releasing hormone (Crh) is a stress- and immune-responsive neuropeptide secreted from the paraventricular nucleus of the hypothalamus (PVN) to stimulate the hypothalamic-pituitary-adrenal (HPA) axis; however, extra-hypothalamic sources of Crh from the central nucleus of the amygdala (CeA) and bed nucleus of the stria terminalis (BNST) govern specific fear- and anxiety-related defensive behavioral responses. We previously reported that preimmunization with a heat-killed preparation of the immunoregulatory environmental bacterium Mycobacterium vaccae NCTC 11659 enhances fear extinction in a fear-potentiated startle (FPS) paradigm. In this follow-up study, we utilized an in situ hybridization histochemistry technique to investigate Crh, Crhr1, and Crhr2 mRNA expression in the CeA, BNST, and PVN of the same rats from the original study [Fox et al., 2017, Brain, Behavior, and Immunity, 66: 70–84]. Here, we demonstrate that preimmunization with M. vaccae NCTC 11659 decreases Crh mRNA expression in the CeA and BNST of rats exposed to the FPS paradigm, and, further, that Crh mRNA expression in these regions is correlated with fear behavior during extinction training. These data are consistent with the hypothesis that M. vaccae promotes stress-resilience by attenuating Crh production in fear- and anxiety-related circuits. These data suggest that immunization with M. vaccae may be an effective strategy for prevention of fear- and anxiety-related disorders.     

Synaptic sodium spikes trigger long-lasting depolarizations and slow calcium entry in rat olfactory bulb granule cells

In the mammalian olfactory bulb, axonless granule cells mediate self- and lateral inhibitory interactions between mitral/tufted cells via reciprocal dendrodendritic synapses. Synaptic output from granule cells occurs on both fast and slow timescales, allowing for multiple granule cell functions during olfactory processing. We find that granule cell sodium action potentials evoked by synaptic activation of the sensory input via mitral/tufted cells are followed by a long-lasting depolarization that is not observed after current-evoked action potentials or large excitatory postsynaptic potentials in the same cell. Using two-photon imaging in acute rat brain slices, we demonstrate that this prolonged electrical response is paralleled by an unusual, long-lasting postsynaptic calcium signal. We find that this slow synaptic Ca²⁺ signal requires sequential activation of NMDA receptors, a nonselective cation conductance I_CAN and T-type voltage-dependent Ca²⁺ channels. Remarkably, T-type Ca²⁺ channels are of critical importance for the 'globalization' of Ca²⁺ transients. In individual active spines, the local synaptic Ca²⁺ signal summates at least linearly with the global spike-mediated Ca²⁺ signal. We suggest that this robust slow synaptic Ca²⁺ signal triggers dendritic transmitter release and thus contributes to slow synaptic output of the granule cell. Therefore, the synaptic sodium spike signal could represent a special adaptation of granule cells to the wide range of temporal requirements for their dendritic output. Our findings demonstrate with respect to neuronal communication in general that action potentials evoked by somatic current injection may lack some of the information content of 'true' synaptically evoked spikes.     

Identification of a voltage- and calcium-dependent non-selective cation channel in cultured adult and fetal human nasal epithelial cells

The apical membranes of cultured human nasal epithelial cells from adults and fetuses were investigated with the patch-clamp technique. Amiloride-insensitive, calcium- and voltage-dependent, non-selective cation channels were found in 4% of the cell-attached, and 18% of the inside-out and outside-out patches (n=412). Multiple functional channels were present in more than 90% of these patches, with a mean of 3.9 channels per patch (n=55). The current-voltage relationship can be described by the Goldman equations and the single channel conductance was 20.1±0.3 pS (n=29) in adult and 20.7±0.4 pS (n=44) in fetal cells in symmetrical 150mM NaCl solutions. The channels were highly selective for cations: P_Na/P_Cl was 30 in adult and 45 in fetal experiments. They were equally permeable for K⁺ and Na⁺, somewhat less for Cs⁺, and impermeable for choline⁺ and tetraethylammonium⁺. The open probability was voltage dependent: it increased approximately 2-fold with 30mV depolarization in the potential range from −60mV to +60mV. The channels were activated by Ca²⁺ concentrations of about 10⁻⁴M at the cytoplasmic side, but were insensitive to extracellular Ca²⁺ and amiloride (10⁻⁴M). The non-selective cation channels found in apical membranes of cultured fetal nasal epithelial cells were not different from the adult ones.