POPULATION DYNAMICS OF ZEBRA MUSSELS DREISSENA POLYMORPHA (PALLAS, 1771) DURING THE INITIAL INVASION OF THE UPPER MISSISSIPPI RIVER, USA

The aim of this study was to document and model the populationdynamics of zebra mussels Dreissena polymorpha (Pallas, 1771)in Pool 8 of the Upper Mississippi River (UMR), USA, for fiveconsecutive years (1992–1996) following their initialdiscovery in September 1991. Artificial substrates (concreteblocks, 0.49 m² surface area) were deployed on or aroundthe first of May at two sites within each of two habitat types(main channel border and contiguous backwater). Blocks wereremoved monthly (30 ± 10 d) from the end ofMay to the end of October to obtain density and growth information.Some blocks deployed in May 1995 were retrieved in April 1996to obtain information about over-winter growth and survival.The annual density of zebra mussels in Pool 8 of the UMR increasedfrom 3.5/m² in 1992 to 14,956/m² in 1996. The average May–Octobergrowth rate of newly recruited individuals, based on a von Bertalanffygrowth model fitted to monthly shell-length composition data,was 0.11 mm/d. Model estimates of the average survivalrate varied from 21 to 100% per month. Estimated recruitmentvaried substantially among months, with highest levels occurringin September–October of 1994 and 1996, and in July of1995. Recruitment and density in both habitat types increasedby two orders of magnitude in 1996. Follow-up studies will benecessary to assess the long-term stability of zebra musselpopulations in the UMR; this study provides the critical baselineinformation needed for those future comparisons. (Received 5 November 2004; accepted 30 September 2005)     

应用心肺运动试验评估食管癌患者长期新辅助化疗前后整体功能的改变*

目的: 用心肺运动试验（CPET）定量评估化疗对人体整体心肺功能状态的影响。方法: 本研究选取2006年至2007年在MD Anderson癌症中心进行外科手术前化疗的6例食管癌患者。对该6例患者分别行化疗前后最大症状限制性CPET的客观定量评估。结果: ①新辅助化疗前后CPET核心指标的变化：显著降低的核心指标有峰值摄氧量（Peak VO₂）（P<0.05）,无氧阈（AT）、峰值氧脉搏（Peak VO₂/HR）、摄氧通气效率峰值平台（OUEP）（P<0.01）,核心指标显著上升的有VE/VCO₂最小值、VE-vs-VCO₂斜率（P<0.05）。2化疗前后CPET循环指标的变化：患者静息状态及热身状态的VO₂无明显变化,AT （P<0.01）及Peak VO₂ （P<0.05）均有下降。除静息及极限状态的下降不显著外,热身状态的摄氧通气效率（OUE）（P<0.05）及OUE@AT （P<0.01）呈现显著下降。四个状态的VE/ VCO₂均呈现上升趋势,但仅在热身状态的VE/ VCO₂ （P<0.05）及VE/ VCO₂@AT（P<0.01）有统计学意义。四个状态的VO₂ /HR均呈下降趋势,除VO₂/HR@AT（P<0.05）显著下降外,其他三个状态的变化尚无统计学差异。③化疗前后CPET通气指标的变化在整个运动过程中,除热身状态的PETCO₂（P<0.05）显著下降外,其余状态的PETCO₂呈现下降趋势,但尚无统计学差异。呼吸频率、每分通气量几乎无变化。患者四个状态的潮气量、VO₂/RF及VCO₂/RF均呈现下降趋势,但均无统计学差异。四个状态的PETO₂均呈现上升趋势,但无明显统计学差异。结论: 心肺运动试验可以从呼吸、循环、代谢等方面客观定量评估化疗前后机体功能状态的变化。     

Heat Shock Responses of Closely Related Species of Tropical and Desert Fish

Over the past twelve years, we have studied heat shock proteinsin two tropical species, a half dozen desert species and a numberof hemiclones of viviparous fishes in the genus Poeciliopsis.Heat shock protein (Hsp) isoform patterns were determined usinghigh resolution two-dimensional polyacrylamide gels. Two familiesof Hsps were studied in detail, the nucleocytoplasmic 70 kilodaltonHsp70 family and the 30 kilodalton Hsp30 family related to -crystallin.The temperature dependence of Hsp accumulation was investigatedusing both intact fish and cultured cells. When the thresholdtemperatures were mapped onto thermal preference profiles, itwas apparent that the Hsp70 threshold (33°C) was closelylinked to the most frequently selected temperatures and theHsp30 threshold (37°C) was closely linked to high temperaturesthat fish rarely selected, indicating that fish deploy thesetwo molecular chaperones differently. One tropical species P.gracilis is a genetic reservoir for most of the Hsp70 isoformsof the desert species. Acquired resistance to 41°C was stronglycorrelated with Hsp70 abundance for gracilis that containedHsp70 isoform 3 whereas fish lacking this isoform showed similarlevels of acquired thermotolerance which did not correlate withHsp70 abundance, suggesting multiple, compensating mechanismsof acquired resistance. Isoform 3 was degraded in cultured cellsfrom a desert species during several hours of recovery at normaltemperature following heat shock whereas two other Hsp70 isoformswere stable. The implications of this property of isoform 3are discussed.     

Ecteinascidia turbinata Extract Activates Components of Inflammatory Responses Throughout the Phylogenetic Spectrum

The tunicate Ecteinascidia turbinata contains a substance orsubstances capable of exerting a number of biological effects.Extracts of tunicate tissues have been shown to kill tumorcells in vitro and arrest tumor growth in vivo. The extractsalso suppress allograft rejection, graft-US.-host reactionsand lymphocyte proliferative responses as well as humoral responsesto immunization. By modifying the conditions, the extracts couldpotentiate antibody responses. In addition, they augment functionsof monocyte-macrophages as evidenced by in vitro phagocytosis,in vivo clearance, and cytotoxic activity against target cells.After studies in mice, we were able to demonstrate that theextracts could activate the phagocytic systems of shrimp, bluecrab, and fish (the American eel). In fish, the intraperitonealroute was superior to the intravenous route for promotion ofphagocytosis, increase in percent presentation of granulocytesand for enhancement of resistance to bacterial infection. Intrarriuscularand intraperitoneal injection led to local inflammation withaccumulation of granulocytes and macrophages.