Analysis of lymph node dissection in patients with ≥7-cm renal tumors

Purpose

To analyze the role of lymph node dissection (LND) in patients with large renal tumors.

Methods

We performed a retrospective study of patients with renal cell carcinoma ≥7 cm in size undergoing surgery between 1990 and 2012. Primary outcome measures were recurrence-free and overall survival of patients who did and did not undergo LND. Cox proportional hazards regression models were created to account for known risk factors for recurrence and survival. Secondary outcomes were recurrence-free and overall survival by lymph node status, lymph node template and number of lymph nodes removed.

Results

Of 524 patients, 164 had disease recurrence and 197 died. Median follow-up was 5 and 5.5 years for patients who did not die or have a recurrence, respectively. A total of 334 (64 %) patients underwent LND, and node-positive disease was identified in 26 (8 %). For patients who did and did not undergo LND, 5-year recurrence-free survival was 64 and 77 %, respectively. Five-year overall survival was 75 and 78 %, respectively. LND was not a predictor of recurrence or survival in multivariate analysis. Node-positive disease was associated with recurrence (p < 0.0005) and mortality (p = 0.032), although node-positive patients had a 5-year overall survival of 65 %.

Conclusions

We did not find a difference in recurrence-free or overall survival in patients with ≥7-cm tumors whether or not they underwent LND. Node-positive disease was associated with worse outcomes, suggesting that LND provides important staging information that can be important in the design of adjuvant clinical trials.     

Simvastatin and losartan enhance nitric oxide and reduce oxidative stress in salt-induced hypertension

BACKGROUND: The renin-angiotensin-aldosterone system and oxidative stress play a major role in the pathogenesis of hypertension. METHODS: We examined the effects of simvastatin, an HMG-CoA inhibitor, and losartan, an angiotensin type 1 receptor antagonist, in Dahl rats fed a high salt diet (8% NaCl), and treated with either simvastatin (3 mg/kg/d), losartan (10 mg/kg/d), or their combination using the drinking water as vehicle, for 3 weeks. Mean blood pressure (MAP) was measured by tail-cuff plethysmography. Plasma levels of nitric oxide (NO) and prostanoids, as well as plasma and tissue angiotensin II (Ang II) and aldosterone (ALDO) were analyzed by enzyme immunoassay. Renal and aortic superoxide production was determined by fluorescence spectrometry. Vascular reactivity of second-order mesenteric arteries was assessed in vitro. RESULTS: Simvastatin, losartan, and the drug combination attenuated the salt-induced increase in MAP. Plasma NO was elevated by simvastatin, losartan, and the combination, whereas plasma thromboxane was reduced by losartan. Simvastatin, losartan, and the combination reduced renal Ang II, but only the combination reduced cardiac Ang II. Heart and renal ALDO were reduced by simvastatin, losartan, and the combination. Aortic and renal NADPH-dependent superoxide production was reduced by simvastatin, losartan, and the combination. The response to acetylcholine, in mesenteric arteries preconstricted with norepinephrine, was greater in the losartan group. CONCLUSIONS: Thus, treatment with simvastatin and losartan lowered oxidative stress and improved endothelial function. Simvastatin significantly reduced the effect of losartan on vascular reactivity in mesenteric arteries, suggesting that their combination may be contraindicated.     

Prostacyclin Reversal of Lethal Endotoxemia in Dogs

Severe endotoxemia, a condition where microembolization and intravascular coagulation are thought to play important roles, was treated experimentally with prostacyclin (PGI₂). In a study of 24 dogs, 8 control animals injected with 1.75 mg·kg⁻¹ of endotoxin died within 24 h. Six animals given intravenous aspirin 100 mg/kg, 30 min after endotoxin died. 9 of 10 dogs infused with 100 ng PGI₂·kg⁻¹·min⁻¹ for 3 h, given 30 min after the injection of endotoxin survived 24 h (P < 0.025). Injection of endotoxin resulted in a: (a) maximal 62% fall in mean arterial pressure (P < 0.001); (b) transient doubling of mean pulmonary arterial pressure (P < 0.001); (c) initial 70% drop in cardiac index (P < 0.001); (d) decline in blood platelets from 213,700 to 13,700/mm³ (P < 0.001), and leukocytes from 7,719 to < 750/mm³ (P < 0.001); (e) depressed urine output (P < 0.001); (f) 34% decrease in blood fibrinogen (P < 0.01) and an increase in fibrin degradation products > 50 μg/ml (P < 0.001); (g) fivefold increase in circulating cathepsin D titer (P < 0.005) and (h) increase in blood norepinephrine (P < 0.005), dopamine (P < 0.005), and epinephrine (P < 0.001). Aspirin treatment led to an increase in mean arterial pressure (P < 0.001) and mean pulmonary arterial pressure (P < 0.005), but cardiac index, urine flow, platelets, leukocytes, fibrin degradation products, and cathepsin D levels remained similar to untreated controls. After infusion of PGI₂ there was a: (a) prompt increase of cardiac index to base-line levels; (b) late increase in mean arterial pressure (P < 0.005) after the discontinuation of PGI₂ treatment (c) restoration of urine output; (d) increase in circulating platelets to levels still below base line but above untreated control animals (P < 0.05); (e) no effect on circulating leukocyte levels; (f) fall in fibrin degradation products to 11.2 μg/ml (P < 0.05); (g) decline in cathepsin D levels to values 60% lower than the untreated controls (P < 0.025); and (h) reduction in plasma norepinephrine levels to base line at 4 h (P < 0.005). Although the mode of PGI₂ action is not clear, it is effective in the treatment of experimental endotoxemia.     

Carvedilol, a new vasodilator and beta adrenoceptor antagonist, is an antioxidant and free radical scavenger.

The antioxidant effect of carvedilol, a new vasodilating, beta adrenoceptor blocker was studied and compared with five other beta blockers. Carvedilol rapidly inhibited Fe(++)-initiated lipid peroxidation, measured as thiobarbituric acid reactive substance (TBARS), in rat brain homogenate with an IC50 of 8.1 microM. Under the same conditions, the IC50 values of atenolol, pindolol propranolol, celiprolol and labetalol were over 1.0 mM. Carvedilol protected against Fe(++)-induced alpha-tocopherol depletion in rat brain homogenate with an IC50 of 17.6 microM; propranolol, celiprolol and labetalol, up to 200 microM, did not show any effect. Using dihydroxyfumarate/Fe(++)-ADP as a OH.radical generating system and 5,5-dimethyl pyrroline-N-oxide (DMPO) as a trapping agent, the characteristic DMPO-OH signals were monitored by electron paramagnetic resonance. Carvedilol dose-dependently decreased the intensity of the DMPO-OH signal, with an IC50 of 25 microM, whereas propranolol, at 500 microM, and U74500A, a 21-aminosteroid, at 100 microM, had no effect. The antioxidant effect of carvedilol mainly resides in the carbazole moiety, and the substitution of a hydroxyl group at certain positions on the phenyl ring of either carbazole or the ortho-substituted phenoxylethylamine part of carvedilol resulted in an increase in antioxidant activity. Furthermore, the protective effect of carvedilol analogs against OH.-mediated neuronal death positively correlated to their antioxidant effect. We conclude that carvedilol is a far more potent antioxidant than other commonly used beta blockers. The apparent mechanism of carvedilol's inhibition of lipid peroxidation is mainly via scavenging free radicals. This novel property of carvedilol may contribute to the known cardioprotective activity of this compound.     

葡萄糖酸镁对离体大鼠心肌缺血再灌注细胞凋亡的抑制效应

目的:观察葡萄糖酸镁对离体大鼠心肌缺血再灌注损伤心肌细胞凋亡的影响。方法:实验于2005-10/2006-01在辽宁医学院药理实验室完成。选用雄性SD大鼠48只,体质量250～300g,按随机排列表法将大鼠分为对照组、缺血再灌注组、葡萄糖酸镁组,每组16只,建立Langendorff离体大鼠心肌缺血再灌注损伤模型。(1)每组各取8只:①对照组:改良的K-H缓冲液持续灌流110min。K-H缓冲液成分(mmol/L)如下:NaCl118.1,NaHCO325.0,KH2PO41.2,MgSO40.6,CaCl22.0,KCl4.7,Glucose11.0。②缺血再灌注组:改良的K-H缓冲液持续灌注至各项指标稳定后,约20min,停灌30min,再灌60min。③葡萄糖酸镁组:灌注方法同缺血再灌注组,但将K-H缓冲液内加葡萄糖酸镁2.4mmol/L。取左室心肌标本测总超氧化物歧化酶活性,丙二醛、Ca2 含量。(2)每组其余8只:①对照组K-H缓冲液持续灌流170min。②缺血再灌注组和葡萄糖酸镁组持续灌注至各项指标稳定后停灌30min,再灌注120min。观察对细胞凋亡的影响。(3)组间计量资料差异比较采用单因素方差分析。结果:SD大鼠共48只均进入结果分析。①缺血再灌注组大鼠心肌组织中丙二醛、Ca2 含量较对照组明显升高(P<0.01),总超氧化物歧化酶活性较对照组明显降低(P<0.01)。②葡萄糖酸镁组与缺血再灌注组比较,总超氧化物歧化酶活性明显升高(P<0.01),丙二醛、Ca2 含量明显降低(P<0.01)。③缺血再灌注组细胞凋亡指数显著高于对照组(P<0.01)。④葡萄糖酸镁组细胞凋亡指数与缺血再灌注组比较显著降低(P<0.01)。结论:葡萄糖酸镁有抑制心肌缺血再灌注损伤中心肌细胞凋亡的作用。其机制可能与葡萄糖酸镁减轻钙超载、清除氧自由基、减少脂质过氧化有关。     

Monoclonal antibodies to T-2 toxin. In vitro neutralization of protein synthesis inhibition and protection of rats against lethal toxemia.

A murine monoclonal antibody (15H6) against the trichothecene mycotoxin T-2 was capable of neutralizing the in vitro protein synthesis inhibitory effect of T-2 toxin in human B lymphoblastoid cultures. It was further shown that 15H6 given to rats (250 mg/kg) 30 min before or 15 min after a lethal dose (1 mg/kg) of T-2 toxin conferred 100% survival. A lower dose of 15H6 (125 mg/kg), given 15 min after the lethal dose of T-2 toxin, protected 25% of the rats. An increased time to death and 45% survival was seen in rats given the full dose of 15H6 antibody 60 min after lethal toxin. These data are the first demonstration of effective prophylaxis and therapy for T-2 toxemia.     

The role of AKT isoforms in glioblastoma: AKT3 delays tumor progression

The growth factor receptor/PI3K/AKT pathway is an important drug target in many cancers including Glioblastoma. AKT, a key node in the pathway, has 3 isoforms, AKT1, AKT2 and AKT3. Here we investigate their role in GBM. We find each activated, ser473 phosphorylated isoform is present in some GBMs but expression patterns vary. There is a direct relationship between human GBM patient outcome and both AKT1 and AKT2 mRNA levels, but an inverse relationship with AKT3 mRNA. Furthermore, AKT3 mRNA levels were high in a less aggressive GBM subtype. Overexpressing AKT3 improves survival in a rodent model of GBM and decreases colony forming efficiency, but not growth rate, in glioma cells. Silencing AKT3 slows cell cycle progression in one cell line and increases apoptosis in another. Our studies of AKT3 substrates indicate (1) silencing both AKT2 and AKT3 reduces GSK3 phosphorylation (2) only AKT2 silencing reduces S6 phosphorylation. Since S6 phosphorylation is a marker of mTORC1 activity this indicates that AKT2 activates mTORC1, but AKT3 does not. Our results indicate AKT isoforms have different roles and downstream substrates in GBM. Unexpectedly, they indicate AKT3 delays tumor progression. Therefore strategies that inhibit AKT3 may be unhelpful in some GBM patients.     

Reversal of intracellular toxicity of the trichothecene mycotoxin T-2 with monoclonal antibody

The trichothecene mycotoxin T-2 is a potent inhibitor of intracellular protein synthesis. We have previously shown that a mouse immunoglobulin G1 monoclonal antibody (15H6) specific for T-2 toxin can neutralize the in vitro protein synthesis inhibitory effect of the toxin in human B-lymphoblastoid cultures, and protect rats from lethal toxemia. We now report that these monoclonal antibodies can induce the net efflux of [3H]-T-2 toxin from poisoned human B-lymphoblastoid cells in vitro, and restore protein synthesis. Administration of the monoclonal antibodies (250 mg/kg) 30 min before infusion of a lethal dose (1 mg/kg) of T-2 toxin causes the sequestration of the toxin in the plasma compartment. When administered 35 min after T-2 toxin, a time when the bulk of toxin is in the tissues, the monoclonal antibodies facilitate the migration of toxin back into the plasma compartment. These data demonstrate that monoclonal antibodies can be of therapeutic value against an intracellular toxin.