Association between Autonomic Control Indexes and Mortality in Subjects Admitted to Intensive Care Unit

正Whether autonomic markers derived from spontaneous fluctuations of heart period (HP) and systolic arterial pressure (SAP) and from their interactions with spontaneous or mechanical respiration (R) are associated with mortality in patients admitted to intensive care unit (ICU). Three-hundred consecutive HP,SAP and R values were recorded during the first day in ICU in 123 patients. Population was divided into     

不同压力及时间机械通气对大鼠血清白细胞介素8、白细胞介素10水平和肺组织形态学的影响

Objective To investigate the effects of mechanical ventilation with different pressure and duration on plasma IL-8 , IL-10 and lung ultrastructure in rats. Methods Thirty adult male SD rats weighting 200-220 g were randomly divided into 5 groups ( n=6 each ):control group ( group C ) , 2 h low airway pressure group (group L2, ventilated for 2 h at 15 cm H2O ) , 4 h low airway pressure group ( group L4, ventilated for 4 h at 15 cm H2O ) , 2 h high airway pressure group ( group H2, ventilated for 2 h at 25 cm H2O ) and 4 h high airway pressure group ( group H4 , ventilated for 4 h at 25 cm H2O).Mechanical ventilation was given at a rate of 40 tpm, at specified pressures for designed duration. The rats were sacrificed at 2 h or 4 h after ventilation. Blood samples were then collected and tested for levels of IL-8 and IL-10. Changes in lung ultrastructure was observed under light and electronic microscopes respectively. Results Compared with group C,the levels of IL-8 and IL-10 were significantly higher in groups L2, Lt, H2 and H4. Moreover, these levels appeared increasing along with longer duration of ventilation, with higher values in group L4 vs group L2 [IL-8: (71.5±7.6) ng/L vs (38.4±6.3) ng/L,IL-10:(364.5±18.6) ng/Lvs (271.6+21.3) ng/L, P<0.05], and in group H4 vs group H2 [IL-8: (140.7±23.5) ng/L vs (76.4±9.2) ng/L, IL-10: (472.8±22.5) ng/L vs (357.6±20.4) ng/L, P<0.05]. Over the same duration, levels of IL-8 and IL-10 were significantly greater with higher pressure used, namely, higher values in group H2 vs group L2, and in group H4 vs group L4 (P<0.05). Compared with group C, various degrees of inflammatory infiltration, emphysema, mitochondrial edema, dilated endoplama reticulum and expanded perinuclear space of lung ultrastructure existed in the other groups as shown by both light and electronic microscopes, which appeared to deteriorate along with longer ventilation time and higher pressure. Conclusions Higher pressure and longer duration for mechanical ventilation may induce IL-8 and IL-10, and also deteriorate lung tissue injury. Effective control of ventilation pressure and duration may ameliorate inflammation and injury of lung tissue.     

双相气道正压无创机械通气时阻塞性睡眠呼吸暂停综合征患者上呼吸道影像分析

目的 应用多层螺旋CT对阻塞性睡眠呼吸暂停综合征(OSAS)患者不同通气状态下上呼吸道行放射学成像,分析在全身麻醉无自主呼吸条件下双相气道正压(BiPAP)无创机械通气是否能克服上呼吸道阻力达到有效的机械通气.方法 选择拟行咽腭成形术的OSAS患者10例,手术前常规实施麻醉诱导睡眠.分别对患者清醒状态下自主呼吸(清醒期)、睡眠诱导后意识消失(诱导期)、BiPAP无创机械通气后5 min(通气期)时头部正位和侧位作螺旋CT扫描,测量上呼吸道各软组织区[软腭后区(RP)、舌根后区(RG)、会厌区(EPG)]的最窄气道横截面左右径、前后径长度及相应横截面积,并监测扫描过程中的无创血压(NIBP)、脉搏血氧饱和度(SpO2)、心率(HR)、自主呼吸频率(RR).结果 头颈部正位扫描显示诱导期RP区和EPG区最窄气道横截面左右径、前后径线长度比清醒期明显缩短,各区横截面积明显缩小[RP区:0.00(0.00,0.60)mm2比38.34(10.57,72.76)mm2,RG区:145.16(0.00,183.72)mm2比177.79(111.05,216.27)mm2,EPG区:39.02(7.55,86.36)mm2比154.69(124.74,322.00)mm2,均P＜0.05].通气期各横截面径线和面积较清醒期仍明显缩小(均P＜0.05),但与诱导期差异无统计学意义(均P＞0.05).头部侧位诱导期除RG区左右径外,各区最窄气道横截面左右径、前后径线长度均短于清醒期,横截面积亦缩小[RP区:0.00(0.00,18.74)mm2比61.46(36.77,141.46)mm2,RG区:69.75(35.74,214.83)mm2比287.68(197.01,393.18)mm2,EPG区:17.28(4.37,65.45)mm2比293.76(254.63,374.83)mm2,均P＜0.05].BiPAP通气时各区横截面径线与清醒期比较尚明显缩短,横截面积虽缩小却较诱导期明显回升(均P＜0.05).各期正、侧位NIBP、HR无明显变化,诱导期RR明显受抑制,SpO2降低(均P＜0.05),通气期RR、SpO2与诱导期比较虽有所改善,但差异无统计学意义(均P＞0.05),仍未回复到清醒期水平(均P＜0.05).结论 OSAS患者睡眠诱导后上呼吸道通畅度明显下降,即使将头部侧位后仍未能改善上呼吸道的通畅度,无自主呼吸的状态下应用BiPAP无创机械通气不能克服上呼吸道阻力达到有效通气,需特殊处理保证安全.     

兔胫骨大段完全骨缺损的解剖学模型构建

BACKGROUND:Tissue-engineered bone has been considered to be a promising candidate for the repair and reconstruction of load-bearing large segmental bone defects. Currently, the studies on the application of tissue-engineered bone mainly focus on cell-scaffold or cytokine-scaffold constructs, which have shed light upon the repair of large segmental bone defects. OBJECTIVE: To establish simple and convenient tissue engineering of anatomically shaped tibial bone defect models using three-dimensional rapid prototyping technology to manufacture rabbit tibia biomimetic artificial bone scaffolds. METHODS:Three-dimensional electronic models were constructed using Mimic software. Hydroxyapatite/polycaprolactone scaffolds were manufactured by fused deposition modeling equipment. Fifty rabbits aged 6 months were randomly divided into three groups: blank control (n=3), control (n=6) and experimental groups (n=6), respectively. Tibial defects ranged 1.2 cm were made in all groups. No treatment was given in blank control group. The bone defects in control and experimental groups were repaired with autogenous osteotomized bone and anatomical tissue-engineered bone, respectively, and fixed with plates and screws. RESULTS AND CONCLUSION: (1) Rabbit tibial bone measurements: tibial length was (93.77±0.59) mm, tibiofibular transverse diameter (8.36±0.13) mm, sagittal diameter (5.97±0.12) mm, average thickness of bone cortex (1.20±0.10) mm, average diameter of the medullary cavity (4.30±0.06) mm. Angle between the connection line of the midpoints of superior and inferior articular surfaces at the side of tibial bone models and the connection line of the midpoints of superior and inferior intersecting surfaces at the side of osteotomized bone models was α=(5.97±0.13)°. (2) X-ray in bone defects: at postoperative 4 and 12 weeks, no obvious displacement and angulated deformity were found in bone grafts, suggesting the good bone defect repair. (3) Histological examination: at postoperative 4 weeks, bone scaffolds were filled with new bone in the experimental group. Furthermore, considerably increased new bone formation and mineralization were observed at postoperative 12 weeks. (4) General observation: no obvious displacement and angulated deformity occurred in bone defect grafts at postoperative 4 and 12 weeks. These findings suggest that rabbit anatomical models of large segmental tibial bone defects with good stability were constructed using three-dimensional prototyping technology, which may simulate the structure and function of bone tissue and be used for guiding the new bone regeneration. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

光学相干断层成像在肺动脉介入诊疗中的应用

Objective To evaluate the feasibility and efficacy of optical coherent tomography (OCT) in differential diagnosis and treatment of pulmonary vascular diseases. Methods OCT system (Lightlab, US) was used to scan 16 pulmonary vessels with diameters ranging from 2 mm to 6 mm in 10 patients with vascular stenosis and/or occlusion (after prior interventional revascularization) confirmed by pulmonary arteriography, followed by measurement and analysis with the built-in software of the system.Results Sixty- six OCT scans were performed for 16 pulmonary vessels in 10 patients, generating characteristic images in all the cases without any complications. Manifestations in OCT scans included pulmonary thromboembolism (n=5) with normal arterial wall thickness, red or white thrombus adhering to intima and stenosed lumen; idiopathic pulmonary hypertension (n=3) with pulmonary arteries 2 mm to 6 mm in diameter, disappearance of normal 3-layered structure of vessel wall, granulation and incrassation of intima, increased reflection, lumen stenosis ＞ 50%, and minimum inner diameter of lumen no more than 1 mm; pulmonary arterial occlusion of unknown reason (n=2) with normal or thickened intima, fibroid hyperplasia 0.17 mm to 0.60 mm by thickness, fistulous adherence to intima causing 60%-80% occlusion of lumen. Post- interventional revascularization of pulmonary arterial occlusion and/or stenosis: incomplete intima, subintima lipid plaques, multiple lesions with fracture of plaques, fragmented intima, red and white thrombus, and formation of local dissection. Conclusion OCT can be safely performed in various phases of pulmonary arterial diseases, and may demonstrate characteristic histological changes of vessel wall in different pulmonary angiopathy, facilitate diagnosis and differential diagnosis, and guide the therapy of pulmonary arterial diseases.     

丙泊酚镇静下瑞芬太尼抑制喉罩置管和气管插管心血管反应的半数有效浓度比较

Objective To measure the medium effective concentration (EC50) of remifentanil for blunting cardiovascular response to placement of LMA-Fastrach, LMA-Proseal and tracheal intubation, and to compare the change of brain bispectral index (BIS) during these procedures. Methods Sixty-three patients (ASA I-II) scheduled for cholecystectomy under general anesthesia were enrolled. According to different options of intubation, all the patients were randomly allocated into three groups (n=21 each): group T by laryngoscope and tracheal intubation, group F by LMA-Fastrach and group P by LMA-Proseal.Initially, a target plasma concentration of 4 mg/L propofol was chosen, and was adjusted to maintain BIS between 45 and 55. Then, the effect-site concentration of remifentanil was started at designed concentration according to Minto's pharmacokinetic model. Five minutes later, 0.6 mg/kg (2 ED95) rocuronium was given, and intubation was performed 2 min after rocuronium administration. The pre- and post-induction mean arterial pressure (MAP), heart rate (HR) and BIS were compared among these groups. MAP and HR at 1 and 2 min pre-intubation and at 5 min post-intubation were also recorded to evaluate whether there was a cardiovascular response in these patients. Subsequently, the EC50 of remifentanil for blunting the cardiovascular response to 3 options of intubation was calculated using the Dixon-Mood up- and down- sequence. Results Compared with pre-induction, all the patients in 3 groups experienced significantly lower post-inductive MAP and HR [MAP of pre- and post-induction in T, F, P groups were (87.9±10.5) mm Hg vs (71.6±9.0) mm Hg, (91.8±8.8)mm Hg vs (73.5±9.9) mm Hg, (87.2±10.2) mm Hg vs (70.9±8.6) mm Hg, HR of pre- and post-induction in T, F, P groups were (78.8±11.6) min-1 vs (68.7±8.5) min-1,(74.8±10.3) min-1 vs (64.1±6.7) min-1, (76.7±8.2) min-1 vs (67.3±8.3) min-1,1 mm Hg=0.133 kPa, P<0.05] but BIS unchanged basically (P>0.05). The EC50 of remifentail for blunting cardiovascular response to intubation was 4.47 μg/L for group T, 4.78 μg/L for group F and 2.05 μg/L for group P, respectively. Conclusion EC50 of remifentail for blunting cardiovascular responses to intubation as shown by Minto's model appears slightly higher in LMA-Fastrach than that in tracheal intubation, and the lowest is in LMA-Proseal intubation.     

Effects of intrapancreatic neuronal activation on cholecystokinin-induced exocrine secretion of isolated perfused rat pancreas

 The role of intrapancreatic neurons in the action of cholecystokinin (CCK) on pancreatic exocrine secretion of the totally isolated, perfused rat pancreas was investigated. Intrapancreatic neurons were activated by applying electrical field stimulation (EFS) to the isolated pancreas for 45 min. When applying EFS, spontaneous pancreatic secretions of fluid and amylase increased until the second 15-min period of EFS and then decreased during the third 15-min period. Atropine (2 μM) notably reduced the EFS-evoked pancreatic secretions of fluid and amylase. The CCK-induced (10 pM) pancreatic secretions of fluid and amylase elevated further in the first 15-min period of EFS and then gradually resumed to the levels observed during application of CCK alone in the third 15-min period of EFS. However, the CCK-induced pancreatic secretions remained elevated even in the third 15-min period of EFS when an action of endogenous somatostatin was inhibited by cyclo-(7-aminoheptanonyl-Phe-d-Trp-Lys-Thr[BZL]) (10 nM) or pertussis toxin (200 ng/ml). EFS further elevated spontaneous exocrine secretion by the cysteamine-treated (300 mg/kg) pancreas, but this was markedly reduced, to normal levels, by infusing somatostatin (100 pM). EFS increased the numbers of immunoreactive somatostatin cells in the Langerhans’ islets. The results indicate that intrapancreatic neuronal activation influences CCK-induced pancreatic secretions in a dual-phase pattern in the rat: an increase during the early phase and a decrease during the late phase. Endogenous somatostatin released from the islets appears to inhibit the enhancing effect of neuronal activation on CCK-induced pancreatic secretion. Of the intrapancreatic neurons, the cholinergic ones appear to predominate in EFS’s effects on CCK-induced pancreatic secretion. Received: 21 April 1998 / Received after revision: 3 November 1998 / Accepted: 16 November 1998     

转化生长因子-β在哮喘气道炎症与重塑中的作用

Transforming growth factor-β(TGF-β) was reported to be increased in asthma in some studies. Accumulation of TGF-β in airway promotes smooth muscle cell mitogenesis and hyperplasia, and in-duces fibroblast and myofibroblast and smooth muscle proliferation as well as increase in protein synthesis in connective tissue(such as collagen deposition on the reticular basement membrane). The autocrine induction of collagen expression by smooth muscle may contribute to the thickening of the reticular basement membrane, irre-versible f‘throsis and remodeling seen in the airways in some asthmatics. TGF-β is considered to be a major fi-brogenic cytokine. It can increase smooth muscle mass and lead to severe bronchial obstruction in an asthma at-tack.     

肌力训练对脑卒中恢复期偏瘫患者大腿表面肌电的影响

Objective To explore the effect of muscle strength exercise on surface electromyography (sEMG) over thigh in stroke patients with hemiplegia during convalescence so as to gain objective evidence for rehabilitation therapy of stroke patients. Methods Thirty-five stroke patients with hemiplegia during convalescence were enrolled in this study, and were divided into two groups, treatment group (n=19) and control group (n=16). The treatment group underwent muscle strength exercise for 6 weeks. Before and after treatment, sEMG signals over vastus medialis (VM), rectus femoris muscle (RF),vastus lateralis (VL), biceps femoris (BF) and semitendinosus (ST) and semimembranosus (SM) during maximal isometric voluntary contraction (MIVC) of the affected knee extension and flexion were recorded.Torque of knee joint extension and flexion, root mean square (RMS) and co-contraction ratio (CR) were computed. No rehabilitation training was performed in control group. The above mentioned indexes of control group were also recorded. Results After treatment, obvious changes were observed in MIVC torque of the affected knee flexion [ (18.02±6.52) nm vs (13.12±5.79) nm, P＜0.05] and extension [ (45.72±17.21 ) nm vs (34.76± 17.19) nm, all P＜0.05 ]. There were no significant differences in CR of flexion and extension. No statistical difference was observed in MIVC torque and CR of flexion and extension before and after treatment in control group (all P＞0.05). RMS value significantly improved when RF, VL, ST and SM over affected thigh were agonist after treatment [ (146.60±60.85) μV vs (97.02±57.17) μV, (172.65±60.73) μV vs ( 131.46 ± 52.15 ) μV, ( 188.69 ± 89.60) μV vs ( 130.57 ± 73.76) μV, all P＜0.05 ]. There were no significant differences of RMS value in the VM and BF before and after treatment (all P＞0.05), and no RMS changes were noted in control group (all P＞0.05). Conclusions Strength exercise may improve strength of flexion and extension over lower limbs in stroke patients with hemiplegia during convalescence, however, it will not induce abnormal contraction of flexion and extension. sEMG combined with torque measurement may assess functional status of hemiplegic limbs effectively.     

Intersegmental synchronization of spontaneous activity of dorsal horn neurons in the cat spinal cord

Extracellular recordings of neuronal activity made in the lumbosacral spinal segments of the anesthetized cat have disclosed the existence of a set of neurons in Rexed's laminae III–VI that discharged in a highly synchronized manner during the occurrence of spontaneous negative cord dorsum potentials (nCDPs) and responded to stimulation of low-threshold cutaneous fibers (<1.5×T) with mono- and polysynaptic latencies. The cross-correlation between the spontaneous discharges of pairs of synchronic neurons was highest when they were close to each other, and decreased with increasing longitudinal separation. Simultaneous recordings of nCDPs from several segments in preparations with the peripheral nerves intact have disclosed the existence of synchronized spontaneous nCDPs in segments S1–L4. These potentials lasted between 25 and 70 ms and were usually larger in segments L7–L5, where they attained amplitudes between 50 and 150 μV. The transection of the intact ipsilateral hindlimb cutaneous and muscle nerves, or the section of the dorsal columns between the L5 and L6, or between the L6 and L7 segments in preparations with already transected nerves, had very small effects on the intersegmental synchronization of the spontaneous nCDPs and on the power spectra of the cord dorsum potentials recorded in the lumbosacral enlargement. In contrast, sectioning the ipsilateral dorsal horn and the dorsolateral funiculus at these segmental levels strongly decoupled the spontaneous nCDPs generated rostrally from those generated caudally to the lesion and reduced the magnitude of the power spectra throughout the whole frequency range. These results indicate that the lumbosacral intersegmental synchronization between the spontaneous nCDPs does not require sensory inputs and is most likely mediated by intra- and intersegmental connections. It is suggested that the occurrence of spontaneous synchronized nCDPs is due to the activation of tightly coupled arrays of neurons, each comprising one or several spinal segments. This system of neurons could be involved in the modulation of the information transmitted by cutaneous and muscle afferents to functionally related, but rostrocaudally distributed spinal interneurons and motoneurons, as well as in the selection of sensory inputs during the execution of voluntary movements or during locomotion. Electronic Publication     

Prior airway exposure to allergen increases virus-induced airway hyperresponsiveness

BACKGROUND: Respiratory syncytial virus (RSV) bronchiolitis in early life can lead to changes in airway function, but there are likely additional predisposing factors, such as prior allergen exposure, determining which children develop wheezing and asthma. OBJECTIVE: To define the effects of prior airway exposure to sensitizing allergen on the development of airway inflammation and hyperresponsiveness (AHR) to subsequent RSV infection. METHODS: BALB/c mice were exposed to ovalbumin or PBS exclusively through the airways and subsequently infected with RSV or sham-inoculated. AHR, lung inflammation, and the frequency of cytokine-producing T lymphocytes in the lung were determined. RESULTS: In PBS-exposed mice, RSV infection induced AHR and an increased proportion of TH1-type (IFN-gamma and IL-12) cytokine-producing cells in the lungs. However, in mice previously exposed to ovalbumin through the airways and subsequently infected with RSV, the degree of AHR was significantly increased and was associated with an increased proportion of TH2 (IL-4, IL-5) cytokine-producing T lymphocytes. This response was also associated with an increased accumulation of eosinophils, neutrophils, and CD8+ T cells in the lungs. CONCLUSIONS: These data suggest that prior airway exposure to allergen may predispose sensitized hosts to a greater degree of altered airway function upon subsequent respiratory viral infection.     

Ultrastructural changes in rat airway epithelium in asthmatic airway remodeling

ObjectivesTo explore asthmatic rat airway epithelial cells mitochondrial ultrastructure changes.MethodsSix female Wistar rats of the same weight (60–80 g) were randomly divided into two groups: the asthmatic group and the control group. According to the OVA inhaled method, the asthmatic airway remodeling rat model was established. Epithelial tissue of the rat trachea was taken from the two groups for transmission electron microscopy (TEM); we counted the number of mitochondria and observed the airway ciliated epithelium, intercellular collagen deposition in the two rat groups and mitochondrial ultrastructure change.ResultsAirway multilayer ciliated epithelium develops, with cilia fallen off; goblet cells increased and irregular, mitochondrial basement membrane density is decreased, mitochondrial crista is reduced, and the nucleus has more incisures and irregular shape in asthmatic rats; airway epithelial cell matrix collagen deposition increased; and lamellar body and mitochondrial cavity formation.ConclusionsIn the asthmatic rat airway, epithelial cells undergo apoptosis and the numbers of mitochondria increased compared with the ones in normal rat airway but lose normal structure.     

Irritant-induced airway disorders

Thousands of persons experience accidental high-level irritant exposures each year but most recover and few die. Irritants function differently than allergens because their actions proceed nonspecifically and by nonimmunologic mechanisms. For some individuals, the consequence of a single massive exposure to an irritant, gas, vapor or fume is persistent airway hyperresponsiveness and the clinical picture of asthma, referred to as reactive airways dysfunction syndrome (RADS). Repeated irritant exposures may lead to chronic cough and continual airway hyperresponsiveness. Cases of asthma attributed to repeated irritant-exposures may be the result of genetic and/or host factors.     

Regulation of airway surface liquid volume by human airway epithelia

Mucus clearance on airway surfaces is a primary form of pulmonary defense. The efficiency of mucus clearance in large part depends on the volume of the airway surface liquid components, including both the periciliary liquid (PCL) layer and the mucus layer. Studies with in vitro model systems suggest that the mucus layer acts as a passive reservoir to redistribute water to and from, as needed, the PCL layer. In contrast, the overall volume of airway surface liquid is determined by active transepithelial salt transport. Data from in vitro systems suggest that airway epithelia have the capacity to both absorb and secrete liquid in response to the volume requirements on the apical surface. At present, the nature of the signals that transmit information about airway surface liquid volume to epithelia and their sensors are unknown. However, progress in elucidation of this system is important, because it appears that these systems are deranged in the genetic disease cystic fibrosis, which is characterized by airway surface liquid volume depletion, mucus stasis, and chronic infection. Thus, insights into these systems may offer novel therapeutic opportunities to correct this physiologic dysfunction of airway epithelia.     

Glutathione redox regulates airway hyperresponsiveness and airway inflammation in mice

Glutathione is the major intracellular redox buffer. We have shown that glutathione redox status, which is the balance between intracellular reduced (GSH) and oxidized (GSSG) glutathione, in antigen-presenting cells (APC) regulates the helper T cell type 1 (Th1)/Th2 balance due to the production of IL-12. Bronchial asthma is a typical Th2 disease. Th2 cells and Th2 cytokines are characteristic of asthma and trigger off an inflammation. Accordingly, we studied the effects of the intracellular glutathione redox status on airway hyperresponsiveness (AHR) and allergen-induced airway inflammation in a mouse model of asthma. We used gamma-Glutamylcysteinylethyl ester (gamma-GCE), which is a membrane-permeating GSH precursor, to elevate the intracellular GSH level and GSH/GSSG ratio of mice. In vitro, gamma-GCE pretreatment of human monocytic THP-1 cells elevated the GSH/GSSG ratio and enhanced IL-12(p70) production induced by LPS. In the mouse asthma model, intraperitoneal injection of gamma-GCE elevated the GSH/GSSG ratio of lung tissue and reduced AHR. gamma-GCE reduced levels of IL-4, IL-5, IL-10, and the chemokines eotaxin and RANTES (regulated on activation, normal T cell expressed and secreted) in bronchoalveolar lavage fluid, whereas it enhanced the production of IL-12 and IFN-gamma. Histologically, gamma-GCE suppressed eosinophils infiltration. Interestingly, we also found that gamma-GCE directly inhibited chemokine-induced eosinophil chemotaxis without affecting eotaxin receptor chemokine receptor 3 (CCR3) expressions. Taken together, these findings suggest that changing glutathione redox balance, increase in GSH level, and the GSH/GSSG ratio by gamma-GCE, ameliorate bronchial asthma by altering the Th1/Th2 imbalance through IL-12 production from APC and suppressing chemokine production and eosinophil migration itself.