Pentoxifyllin Attenuates the Systemic Inflammatory Response Induced During Isolated Limb Perfusion With Recombinant Human Tumor Necrosis Factor-α and Melphalan

Background: Isolated limb perfusion (ILP) with recombinant human tumor necrosis factor- (rhTNF-) and melphalan harbors the risk of septic shock–like syndrome. Pentoxifyllin (PTX) produced a beneficial effect on cytokine response and survival in animal experiments of septic shock, and we were interested to explore its effect during TNF-ILP in humans.Methods: Eighteen consecutive patients underwent TNF-ILP and received PTX (30 mg/kg/day), whereas another 13 consecutive patients did not. PTX was given systemically after the limb extracorporeal circulation was started. Cardiac index, systemic vascular resistance (SVR), and pulmonary vascular resistance were recorded via a Swan-Ganz catheter. Blood levels of TNF-, interleukin-6, procalcitonin, and lipopolysaccharide-binding protein were determined before, during, and after ILP.Results: After reperfusion, systemic levels of TNF- were significantly less increased in the PTX group (peak, 2.8 vs. 1.3 ng/mL; P < .05), as were interleukin-6 values (peak, 68 vs. 22 pg/mL; P < .02) and lipopolysaccharide-binding protein plasma levels (peak, 215 vs. 105 g/mL; P < .03). Differences in cardiac index, SVR, and mean arterial blood pressure were not significantly different. Norepinephrine or dobutamine to maintain SVR was less required in the PTX group.Conclusions: PTX attenuates systemic cytokine production and influences components of the systemic inflammatory response after TNF-ILP. PTX may play a beneficial role in the management of septic shock–like syndrome, particularly in patients with leakage from the ILP circuit.Presented at the 55th Annual Meeting of the Society of Surgical Oncology, Denver, Colorado, March 14–17, 2002.     

Effects of sustained post-traumatic shock and initial fluid resuscitation on extravascular lung water content and pulmonary vascular pressures in a porcine model of shock

Background. The temporal evolution of lung injury followingpost-traumatic shock is poorly understood. In the present studywe have tested the hypothesis that manifestations of pulmonaryvascular dysfunction may be demonstrable within the first hourafter the onset of shock. Methods. Twenty-nine anaesthetized pigs (mean weight 27.4 kg;(SD) 3.2) were randomly allocated to three groups: control (C,n=9), shock resuscitated with either NaCl 0.9% (S, n=10), or4% gelatine (G, n=10). Shock was maintained for 1 h followedby fluid resuscitation with either normal saline or 4% gelatinesolution. Cardiac output (CO), mean arterial pressure (MAP),mixed venous saturation (Sv_O2), blood lactate concentration,mean pulmonary artery pressure (MPAP), MPAP/MAP, pulmonary vascularresistance (PVR), extravascular lung water index (EVLWi), Pa_O2/FI_O2,venous admixture (Q^·_S/Q^·_T), and dynamic lung compliance(C_dyn) were measured at baseline, beginning of shock phase,end of shock phase, and post-resuscitation. Results. At the end of volume resuscitation CO was restoredto control values in both shock groups. MAP remained significantlybelow control values (95% CI: C=70–95, S=28–52,G=45–69 mm Hg) in both shock groups. MPAP/MAP was significantlygreater in both shock groups at the end of the shock phase (95%CI; C=0.15–0.24, S=0.28–0.38, G=0.32–0.42)and at the post-resuscitation phase (95% CI: C=0.12–0.30,S=0.43–0.61, G=0.32–0.49) indicating the presenceof relative pulmonary hypertension. This was associated witha significant increase in PVR in Group S (F=3.9; P<0.05).There were no significant changes in Pa_O2/FI_O2, Q^·_S/Q^·_T,EVLWi, or C_dyn. In a small cohort of animals a measurable increasein EVLWi (>30%) and reduction in C_dyn (>10%) were observed. Conclusions. Pulmonary vascular injury manifesting as relativepulmonary hypertension and increased PVR may occur within thefirst hour after the onset of shock. These changes may not beaccompanied by overt changes in oxygenation, compliance, orEVLWi. Br J Anaesth 2003; 91: 224–32     

Somatic and visceral afferents to the 'vasodepressor region' of the caudal midline medulla in the rat

Previous research has found that the integrity of a restricted region of the caudal midline medulla (including caudal portions of nucleus raphé obscurus and nucleus raphé pallidus) was critical for vasodepression (hypotension, bradycardia, decreased cardiac contractility) evoked either by haemorrhage or deep pain. In this anatomical tracing study we found that the vasodepressor part of the caudal midline medulla (CMM) receives inputs arising from spinal cord, spinal trigeminal nucleus (SpV) and nucleus of the solitary tract (NTS). Specifically: (i) a spinal-CMM projection arises from neurons of the deep dorsal horn, medial ventral horn and lamina X at all spinal segmental levels, with approximately 60% of the projection originating from the upper cervical spinal cord (C1-C4); (ii) a SpV-CMM projection arises primarily from neurons at the transition between subnucleus caudalis and subnucleus interpolaris; (iii) a NTS-CMM projection arises primarily from neurons in ventrolateral and medial subnuclei. In combination, the specific spinal, SpV and NTS regions which project to the CMM receive the complete range of somatic and visceral afferents known to trigger vasodepression. The role(s) of each specific projection is discussed.     

gp120 neurotoxicity fails to induce heat shock defenses,while the over expression of hsp70 protects against gp120

gp120, the coat glycoprotein of HIV, can damage CNS neurons. This appears to mostly involve an indirect pathway in which gp120 infects microglia, triggering the release of cytokines and glutamatergic excitotoxins which then damage neurons. A well-characterized response of cells to insults is to mobilize the heat stress response, a defense that has a number of protective consequences. We tested the capacity of gp120, at a dose well-documented to be neurotoxic, to activate the heat shock response in cultures from cortex and hippocampus, two brain regions sensitive to the neurotoxic effects of gp120. We found that gp120 failed to induce expression of hsp70, hsp25 or hsp90 in cortical or hippocampal cultures, under conditions where induction can be demonstrated in response to other insults. The failure of gp120 to induce a heat shock response is significant because we subsequently demonstrated that such an induction would have been beneficial. Specifically, over expression of hsp70 with a herpes viral amplicon vector protected cultured hippocampal neurons from gp120 neurotoxicity.     

Science Review: Vasopressin and the cardiovascular system part 1 – receptor physiology

Vasopressin is emerging as a rational therapy for vasodilatory shock states. Unlike other vasoconstrictor agents, vasopressin also has vasodilatory properties. The goal of the present review is to explore the vascular actions of vasopressin. In part 1 of the review we discuss structure, signaling pathways, and tissue distributions of the classic vasopressin receptors, namely V₁ vascular, V₂ renal, V₃ pituitary and oxytocin receptors, and the P₂ class of purinoreceptors. Knowledge of the function and distribution of vasopressin receptors is key to understanding the seemingly contradictory actions of vasopressin on the vascular system. In part 2 of the review we discuss the effects of vasopressin on vascular smooth muscle and the heart, and we summarize clinical studies of vasopressin in shock states.     

Increase in gastric intramucosal hydrogen ion concentration following endotoxin challenge in the rat and the actions of nitric oxide synthase inhibitors

1. Cardiovascular events and outcome in septic shock may be predicted by monitoring the fall in intramural pH (pHi), as an index of splanchnic perfusion and mucosal ischaemia. In the present study, a small animal model for monitoring the changes of gastric pHi or intramucosal [H+] following challenge with the endotoxin lipopolysaccharide (LPS) was developed in the rat. The role of nitric oxide (NO) in these events in this model was evaluated using the non-selective NO synthase (NOS) inhibitors N(G)-nitro-L-arginine methyl ester (L-NAME) and N(G)-monomethyl-L-arginine (L-NMMA). 2. The pHi and intramucosal [H+] were evaluated in omeprazole-pretreated rats (30 mg/kg, i.p.) using the Henderson equation after estimating the PCO2 and the bicarbonate concentration in gastric wall. To measure gastric wall PCO2, the oesophagus was intubated and the pylorus ligated. The PCO2 was measured by a blood gas analyser in 2 mL saline instilled for 30 min in the gastric lumen to equilibrate with the gastric wall. The pHi was measured under basal conditions and 3 and 5 h after LPS (3 mg/kg) administration. Separate groups received treatment with L-NMMA (25-50 mg/kg) or L-NAME concomitantly or 2.5 h after administration of LPS. 3. Intravenous administration of Escherichia coli LPS provoked a significant fall in gastric pHi from 7.37 to 7.18 (median values; n =10-19) determined after 5 h. In groups treated concurrently with LPS and L-NAME (5 mg/kg; n = 19), there was a similar increase in intramucosal [H+] as that induced by LPS alone (n = 15) in those animals that survived. In contrast, L-NAME (5 mg/kg; n = 12), given 2.5 h after LPS challenge, at a time at which inducible NOS is known to be significantly expressed, prevented the increase in intramucosal [H+] at 3 and 5 h after LPS challenge. Similarly, L-NMMA (25-50 mg/kg; n = 23), given 2.5 h after LPS challenge, dose-dependently inhibited the increase in intramucosal [H+] at 3 and 5 h. 4. In conclusion, these findings indicate that this rat model could be useful in exploring the pathophysiology of acute endotoxin shock. Delayed administration of L-NAME and L-NMMA abolished the increase in gastric intramucosal [H+], supporting the involvement of excess NO in the tissue dysfunction associated with endotoxin shock. This suggests the potential value of this small animal model in evaluating the therapeutic activity of novel agents for use in septic shock.     

In Vivo Effect of Pancreatic Phospholipase A2 on the Arachidonic Acid Cascade

Summary Background. In acute pancreatitis, pancreatic phospholipase A₂ increases in systemic circulation. Yet the pathophysiological significance is controversial, because previous in vitro studies have shown that the enzyme has little cytotoxicity or ability to activate the arachidonic acid cascade by itself in contrast to other isozymes. Aim of the Study. The aims of this study are to examine the effect of pancreatic phospholipase A₂ on the arachidonic acid cascade in vivo; to explain the discrepancy, if present, between in vitro and in vivo findings; and to reassess the pathophysiological significance of circulating pancreatic phospholipase A₂. Methods. Pancreatic phospholipase A₂ was infused intravenously in guinea pigs, and changes in the arachidonic acid cascade, plasma lipoprotein, and cardiopulmonary function were investigated. Results. Plasma concentrations of 6-keto-prostaglandin F_1α, prostaglandin E₂, and thromboxane B₂ increased after intravenous (iv) infusion of pancreatic phospholipase A₂. Some of the plasma phospholipids such as phosphatidylcholine and phosphatidylethanolamine decreased, and free dihomo-γ-linolenic acid, arachidonic acid, and eicosapentaenoic acid were detected in plasma. These changes were accompanied with decreases in blood pressure, heart rate, and base excess. Conclusion. Circulating pancreatic phospholipase A₂ activates the arachidonic acid cascade, probably by supplying free eicosanoid precursors from plasma lipoprotein to eicosanoid-producing cells. It is supposed to be a cause of systemic complications in acute pancreatitis.     

Shortening the second phase duration of biphasic shocks: effects of class III antiarrhythmic drugs on defibrillation efficacy in humans

INTRODUCTION: The specific waveform providing optimal defibrillation threshold (DFT) is unknown. We compared the defibrillation efficacy of biphasic pulses with second phases (P2) of 2 and 5 msec in a randomized prospective clinical study. METHODS AND RESULTS: Intraoperative DFTs of 62 patients (age 54 +/- 13 years; ejection fraction 43% +/- 17%; amiodarone 47%, d,l-sotalol 13%) were determined in random order using a binary search protocol. Anodal shocks of 60% tilt first phases (P1) and P2 of 2 msec/5 msec were delivered from two 100-microF capacitors between the right ventricular electrode and the test housing of a Phylax 06/XM device. Mean DFT was significantly lower using the shorter P2 (9.5 +/- 4.5 J vs 11.3 +/- 5.2 J; P < 0.0001). According to subgroup analysis, the effect of changing P2 duration was only influenced by antiarrhythmic treatment. DFT decreased markedly using the shorter P2 in patients treated with amiodarone (10.7 +/- 4.9 J vs 13.4 +/- 5.6 J; P < 0.00001) or d,l-sotalol (6.1 +/- 3.3 J vs 9.1 +/- 4.6 J; P < 0.05). The difference in patients not treated with Class III drugs was found to be insignificant. Chronic amiodarone treatment increased DFT only when the longer P2 was used. CONCLUSION: Biphasic shocks with shorter P2 should be used in patients undergoing Class III antiarrhythmic treatment.     

焦炉工人外周血淋巴细胞HSP 72表达特征

目的 研究焦炉工人外周血淋巴细胞热休克蛋白72(HSP72)表达特征及其影响因素.方法 选取某焦化厂焦炉工人267人和对照30人,蛋白印迹(Western blot)法检测外周血淋巴细胞HSP 72的表达,高效液相色谱法测定作业环境空气中苯并(a)芘[B(a)P]浓度.收集研究对象个人信息.结果 炉顶工、炉侧工外周血淋巴细胞HSP 72表达水平(G±SG)(1.20±0.47,1.30±0.37)显著高于对照组(0.85±0.34),炉侧工显著高于炉底工(1.01±0.35),差异有统计学意义(P＜0.05).不同作业环境[B(a)P]浓度与相应作业区工人外周血淋巴细胞HSP72表达水平呈二项式分布(R2=0.9999).Logistic分析显示,与对照组相比,焦炉逸散物暴露引起淋巴细胞HSP 72表达阳性的调整OR为1.31,其中炉顶工、炉侧工调整OR分别为1.49和2.69.多元线性回归分析显示,在低暴露水平下(炉底工、对照组),吸烟指数和饮酒是HSP 72表达水平升高的抑制因素(β分别为-0.0001和-0.05,P＜0.05).结论 焦炉逸散物可诱导外周血淋巴细胞HSP72表达升高,但高暴露剂量为焦炉逸散物对HSP 72表达有抑制作用.低暴露水平下吸烟和饮酒对HSP 72表达有抑制作用.     

热休克蛋白与视网膜视神经疾病的研究进展

热休克蛋白是细胞在受到各种理化刺激后高效表达的一组蛋白质,具有保护细胞、抵抗细胞凋亡的作用,热休克蛋白在视网膜疾病及视神经再生及修复中的作用已引起人们重视,我们主要对热休克蛋白在视网膜视神经疾病方面的研究进展简要综述.