LAV694, a new antiproliferative agent showing improved skin tolerability vs. clinical standards for the treatment of actinic keratosis

The skin tolerability of the tubulin polymerisation inhibitor LAV694 was compared to that of 5% 5-fluorouracil (5-FU) and 0.5% podophyllotoxin in vitro using a human reconstructed epidermis (HRE), and in vivo using minipigs. Topical treatment of HRE for 1 or 3 days with a 0.2, 0.6 or 1% LAV694 cream or the placebo showed no signs of irritation in terms of morphology, cell viability (lactate dehydrogenase leakage) or interleukin-8 mRNA expression and release. 5-FU increased interleukin-8 production and induced morphological signs of irritation. The substances were also applied under occlusion to the back of two minipigs, twice daily, for 9 days to allow intraindividual comparison of skin effects and tolerability. Skin reactions were monitored by visual scoring, chromometry, pro-inflammatory activity, cell cycle and apoptosis by RT-PCR, laser scanning cytometry and histopathological examination of biopsies. Application of podophyllotoxin and 5-FU had to be stopped on days 4 and 8, respectively, due to severe skin lesions. LAV694 (1%) induced only moderate skin reddening after 9 days. 5-FU and podophyllotoxin, but not LAV694, increased mRNA expression of pro-inflammatory cytokines. LAV694 arrested keratinocytes in the M phase of the cell cycle and apoptosis was detected histologically in the basal layer. LAV694 increased the expression of pro-apoptotic genes in both experimental models. In conclusion, LAV694 selectively induced apoptosis, rather than necrosis, of growth-arrested keratinocytes, thus avoiding the occurrence of extensive inflammation. This resulted in an improved skin tolerability in comparison with 5-FU and podophyllotoxin.     

Effects of bicarbonate buffered dialysate on human peritoneal mesothelial cell intracellular calcium homeostasis

This study compares the biocompatibility of two bicarbonate-based peritoneal dialysis (PD) solutions using the measurement of intracellular free calcium (Ca(i)2+)) as a sensitive parameter of cell function in human peritoneal mesothelial cells (hPMC). Fura-2-loaded hPMC suspensions were exposed to bicarbonate (38 mmol/L) and bicarbonate (25 mmol/L), lactate-buffered PD (15 mmol/L) solutions at pH 7.4 and compared with Krebs-Ringer physiological saline (KRS; pH = 7.4). Resting Ca(i)2+ values and 4br-A23187 (1.0 micro mol/L) induced transients were compared in treatment and control groups. In separate studies, the effect that low saline pH had on Ca(i)(2+) homeostasis was examined. Suspended cells or cells attached to coverslips were bathed in citric acid-phosphate (McIllvaine's) buffered saline (MBS, pH = 7.4). Cells were acidified (pH = 5.3) with citric acid and then challenged with ionophore. Ionophore challenge produced a significantly reduced Ca(i)2+ transient response in cells exposed to the bicarbonate/lactate fluid compared with bicarbonate or KRS. Acidified cell suspensions produced a small monophasic Ca(i)2+ transient rise that was short lived. Gradual recovery of MBS to pH 7.4 produced no changes to Ca(i)2+ homeostasis of cell monolayers. Ionophore treatment produced a biphasic response identical to cells bathed in KRS. This study has demonstrated that short-term exposure to bicarbonate did not alter Ca(i)2+ homeostasis directly, or subsequent modulation of intracellular pH. The MBS system provided a reliable method of modifying the external pH during continuous Ca(i)2+ measurement.     

Adding lactate to the prime solution during hypothermic cardiopulmonary bypass: a quantitative acid-base analysis

Background. The effect of adding lactate to the cardiopulmonarybypass (CPB) prime was investigated using Stewart’s quantitativeacid–base approach. According to this quantitative model,serum pH and bicarbonate are determined by three independentfactors: the partial pressure of carbon dioxide (PCO₂), thetotal concentration of weak acids (e.g. albumin), and the strongion difference. The apparent strong ion difference is calculatedas the sum of sodium, potassium, magnesium and calcium minuschloride concentrations. The pH decreases with a smaller strongion difference and vice versa. Methods. Twenty patients scheduled for coronary surgery werestudied prospectively. All patients were treated identically,except for the prime, which either contained lactate or waslactate free. Just before bypass and before coming off bypass,haemoglobin, glucose, plasma osmolality and colloid osmoticpressure were determined; albumin, lactate, sodium, potassium,ionized calcium, magnesium, phosphate, arterial pH, PCO₂, bicarbonate,and base excess were measured for use in Stewart’s analysis. Results. Metabolic acidosis had resolved by the end of bypasswith the lactated prime. Although the strong ion gap (apparentminus effective strong ion difference) increased significantlyin both groups, its composition differed significantly betweenthe groups. The Stewart technique detected polyanionic gelatinas a weak acid component contributing to the unidentified anionfraction. Colloid osmotic pressure was maintained in both groups. Conclusion. Exogenous lactate attenuates acidosis related toCPB. The oncotic and weak acid deficits produced by hypoalbuminaemiamay be compensated for temporarily during CPB by polyanionicsynthetic colloids such as succinylated gelatin. Br J Anaesth 2003; 90: 440–5     

Dopexamine reverses colonic but not gastric mucosal perfusion defects in lethal endotoxin shock

Background. Whilst dopexamine appears to increase overall splanchnicblood flow in postoperative and septic patients, the effectson gastric mucosal perfusion are controversial and based onconcomitantly increasing mucosal to arterial PCO₂ gradients(PdCO₂). We hypothesized that dopexamine alters splanchnic bloodflow distribution and metabolism during experimental endotoxinshock and modifies the inflammatory response induced by endotoxin. Methods. In an experiment with anaesthetized normovolaemic,normoventilated pigs, 21 animals were randomized into: (i) subacutelethal endotoxin shock for 14 h (n=7 at baseline); (ii)endotoxin shock with dopexamine infusion (aiming to exceed baselinecardiac output, n=7); or (iii) controls (n=7). Regional bloodflow and metabolism were monitored. Results. Endotoxin produced a hypodynamic phase followed bya normo/hyperdynamic, hypotensive phase. Despite increasingsystemic blood flow in response to dopexamine, proportionalsplanchnic blood flow decreased during the hypodynamic phase.Dopexamine gradually decreased fractional coeliac trunk flow,while fractional superior mesenteric arterial flow increased.Dopexamine induced early arterial hyperlactataemia and augmentedthe gastric PdCO₂ gradient while colonic luminal lactate releaseand colonic PdCO₂ gradient were reversed. Dopexamine did notmodify the inflammatory response as evaluated by arterial IL-1ßand IL-6 concentrations. Conclusions. Dopexamine protects colonic, but not gastric mucosalepithelium in experimental endotoxin shock. This may be relatedto redistribution of blood flow within the splanchnic circulation. Br J Anaesth 2003; 91: 878–85     

Clinical significance of anti-GM-CSF antibodies in idiopathic pulmonary alveolar proteinosis

BACKGROUND: The role of anti-granulocyte-macrophage colony stimulating factor (GM-CSF) antibodies as a diagnostic marker in idiopathic pulmonary alveolar proteinosis (iPAP) remains unclear. METHODS: Anti-GM-CSF antibodies were detected in blood and bronchoalveolar lavage fluid (BAL) fluid in 13 patients with iPAP. Three patients with secondary PAP, 35 with other pulmonary disorders, and 10 subjects without lung lesions acted as controls. Blood samples only were obtained from 30 healthy medical personnel. Anti-GM-CSF antibodies were detected using immunoblotting and measured semi-quantitatively by serial dilution or concentration methods. The relationship between antibodies and reported severity indicators for iPAP was analysed. RESULTS: Anti-GM-CSF antibodies could be detected in both blood and BAL fluid samples in 12 of 13 iPAP patients and were undetectable in blood and/or BAL fluid from the other subjects studied. BAL fluid levels of anti-GM-CSF antibodies were highly correlated with the severity indicators for iPAP, including serum lactate dehydrogenase (LDH) levels, arterial oxygen tension, alveolar-arterial oxygen tension difference, (AaPO2), lung carbon monoxide transfer factor, and some lesion scores on chest radiographs and computed tomographic scans. In contrast, blood anti-GM-CSF antibodies were not significantly correlated with the severity indicators evaluated. In addition, patients with iPAP who required subsequent therapeutic lung lavage had significantly higher values of serum LDH, AaPO2, and BAL fluid anti-GM-CSF antibodies, and significantly lower values of PaO2. CONCLUSIONS: In addition to serum LDH levels, PaO2 and AaPO2, BAL fluid levels of anti-GM-CSF antibodies might reflect disease severity in patients with iPAP and predict the need for subsequent therapeutic lung lavage. These findings may expand the role of anti-GM-CSF antibodies in iPAP.     

左旋卡尼汀心脏停搏液对大鼠离体心肌保护作用的研究

目的:观察含左旋卡尼汀(L-CN)冷停搏液对大鼠缺血心肌的保护作用。方法:32只雌性Wistar大鼠随机分为L0、L2.5、L5和L10共4组(n=8),STH液中分别含有L-CN0、2.5、5和10mmol/L。麻醉后开胸取出心脏,立即连于Langendorff灌注装置,制备上述4种心脏停搏液诱导心脏停搏的心脏缺血再灌注模型。分别取停搏前、再灌注15和30min时冠脉流出液2mL检测乳酸脱氢酶(LDH)、肌酸激酶(CK)。实验末留取心尖部心肌组织,检测三磷酸腺苷(ATP)、丙二醛(MDA)和超氧化物歧化酶(SOD)含量。结果:停搏前各组LDH、CK差异无统计学意义(P>0.05),再灌注后各组LDH、CK均有增加(P<0.01);L-CN组的增加幅度明显小于对照组,且随L-CN浓度的增加,增加幅度减少(P<0.05)。加L-CN各组心肌组织ATP、SOD含量明显增高,MDA含量明显下降(P<0.05)。结论:L-CN加入St.Thomas'Ⅱ(STH)停搏液能减轻缺血-再灌注心肌损伤。     

食管癌手术与胃肠道肿瘤手术患者中心静脉血氧饱和度和血乳酸水平的比较

目的对不同的手术制定不同的方案,尽早恢复患者的组织灌注,提高氧储备。方法比较28例食管癌手术病人(食管癌组)和33例胃肠道肿瘤手术病人(胃肠道肿瘤组)术后1、6、24h中心静脉血氧饱和度(ScvO2)、血乳酸水平,以及术后并发症的发生情况。结果术后1h食管癌组患者ScvO2明显低于胃肠道肿瘤组,血乳酸水平明显高于胃肠道肿瘤组,术后6、24h2组ScvO2、血乳酸水平则无明显差异;食管癌手术组术后1h内术后并发症发生率明显高于胃肠道肿瘤组,术后6、24h并发症发生率无明显差别。结论食管癌组术后早期组织缺氧程度明显高于胃肠道肿瘤组,由此造成前者术后早期并发症发生率增高,随着时间推移组织缺氧程度会逐步改善。     

Mechanisms of star fruit-induced acute renal failure

We have previously discovered that star fruit can induce oliguric acute renal failure. To investigate the mechanisms of star fruit-associated acute oxalate nephropathy, the nephrotoxic effect of star fruit was examined in both cellular experiments and animal models. We evaluated renal function, pathological changes in kidney tissues and apoptotic effects using terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) assay in four groups of rats -- a control group (CG), fed with tap water (1); a star fruit group (SG), fed with star fruit juice naturally containing 0.2M oxalate (2); and oxalate groups (OxG), fed with 0.2M (3) or 0.4M (4) oxalate solution. The effects of both star fruit juice and oxalate on MDCK cells were also analyzed by flow cytometry. We found that the mean creatinine clearance was significantly lower in the SG, 0.2M OxG and 0.4M OxG. Dose-dependent apoptotic effects were evident from the TUNEL assay, and flow cytometry analysis of treated MDCK cells showed dose- and time-dependent effects. Our findings suggest that star fruit juice produces acute renal injury, not only through the obstructive effect of calcium oxalate crystals, but also by inducing apoptosis of renal epithelial cells, which may be caused by the levels of oxalate in the fruit.     

Density of amine accumulating neurons in rabbit and guinea-pig retina

Arterial concentrations of free fatty acids (FFA), glycerol and lactate were measured in male Wistar rats before, during and after 30 minutes exercise on a treadmill. The arterial concentration of glycerol increased 120% and lactate 340% during exercise, but fell immediately upon its termination. The arterial concentration of FFA increased only 20% during the exercise, but was followed by a sharp rise in the recovery period. Maximum FFA concentration was found after 6 minutes of recovery, reaching 70% above the preexercise level, whereafter plasma FFA fell. Using radioactively labelled microspheres it was found that the fraction of cardiac output reaching adipose tissue after 10 min of exercise was reduced by 30–90% in relation to the resting value. After 3 min recovery, however, the fractional distribution to the same tissue was in average 300% above the value measured 3 min before termination of exercise. It is concluded that the increase in plasma FFA observed during the early recovery period is caused by increased FFA release from adipose tissue, as a consequence of increased adipose tissue perfusion in the recovery period.     

Metabolic response of endurance athletes to training with added load

Summary Endurance athletes were divided into experimental (n=12) and control (n=12) groups to investigate the effects of extra-load training on energy metabolism during exercise. A vest weighing 9%–10% body weight was worn every day from morning to evening for 4 weeks including every (n=6) or every other (n=6) training session. After 4 weeks the control group had a lower blood lactate concentration during submaximal running, whereas the experimental group had significantly higher blood lactate and oxygen uptake (p<0.01–p<0.05), and a lower 2 mmol lactate threshold (p<0.05) and an increased blood lactate concentration after a short running test to exhaustion (p<0.05). Those experimental subjects (n=6) who used the added load during every training session had a lower 2 mmol lactate threshold, improved running time to exhaustion, improved vertical velocity when running up stairs and an increased during submaximal running after the added load period. It is concluded that the additional loading increased anaerobic metabolism in the leg muscles during submaximal and maximal exercise. An increased recruitment and adaptation of the fast twitch muscle fibres is suggested as the principal explanation for the observed changes.