Regulation of particle transport within the ventral groove of the mussel (Mytilus edulis) gill in response to environmental conditions

To thoroughly understand the feeding processes of the blue mussel, Mytilus edulis, under the variable environmental conditions it experiences in nature, it is important to examine individually the different components of its feeding system. The ciliated ventral food groove represents one of these components, within which the majority of food particles trapped by the gill are transported to the labial palps and mouth. Any ability of the mussel to adjust food transport rates within this groove could serve as an important feeding regulatory mechanism in response to variations in the environment.

Mucous strand velocities in the ventral groove of the mussel, M. edulis, were determined by video endoscopy over different time periods and during short- and long-term manipulations of ambient particle concentration and temperature. Mucous strand velocity decreased with increasing ambient particle concentration at 14°C, but a similar relationship was not observed at 5°C. The data support the hypothesis that M. edulis possesses compensatory mechanisms to control particle transport at the level of the ventral groove cilia in response to changes in the environment. Furthermore, mucous strand velocity in the ventral groove increased when the ambient temperature of mussels acclimated to 5°C was increased to 15°C during acute and long-term acclimation temperature experiments. This response is consistent with standard physiological responses of ciliary systems to changes in temperature.     

慢性腹痛患儿C~(13)-尿素呼气试验与胃镜检查的临床意义

目的了解慢性腹痛患儿幽门螺杆菌(H.pylori)的感染状态及幽门螺杆菌感染患儿内镜下表现的特点。方法应用C13尿素呼气试验,对905例以慢性腹痛为主要症状的患儿进行检测,对C13呼气试验阳性者进行电子胃镜检查。结果905例慢性腹痛患儿中H.pylori呈阳性185例(20.44%),随年龄增长,其H.pylori阳性率升高,学年组已达高峰。对H.pylori阳性者进行胃镜检查结果显示十二指肠隆起病变47例占25.40%,结节性胃炎41例占22.1%,慢性浅表性`胃炎38例占20.5%,结节性胃炎伴十二指肠隆起病变23例占12.43%,十二指肠球部溃疡23例占12.4%。胃溃疡7例,占3.7%(其中包括1例复合性溃疡),结节性胃炎伴十二指肠炎6例,占3.2%。结论H.pylori感染为小儿慢性腹痛的主要原因之一,也是导致慢性胃炎及消化性溃疡的主要原因之一。C13尿素呼气试验方便,快速,无痛苦,无放射性,是一较好的H.pylori检测方法;对既有消化道症状同时C13呼气试验阳性者进行胃镜检查能够协助临床诊断及治疗。     

鼻内镜下鼻窦炎合并中鼻甲外侧壁切除术的临床疗效观察

目的:探讨鼻内镜下行鼻窦炎手术同时行中鼻甲外侧壁切除的疗效。方法:选择本院2009年6月至2013年7月的行鼻内镜下鼻窦炎手术的慢性鼻窦炎患者160例,随机分为观察组和对照组.对照组行单纯的鼻窦炎开放手术,观察组在对照组治疗的基础上行中鼻甲外侧壁切除术。比较两组术后临床疗效、换药平均次数、SNOT-20评分及不良反应等。结果:对照组术后平均换药次数显著高于观察组(P0.05);对照组治疗总有效率为72.50%,显著低于观察组92.50%,差异具有统计学意义(P0.01);两组治疗前SNOT-20评分比较无统计学差异(P0.05),治疗后SNOT-20评分,组内比较均低于治疗前(P0.05);观察组治疗后SNOT-20总分显著低于对照组(P0.05);两组不良反应发生率无显著差异(P0.05)。结论:鼻内镜下鼻窦炎手术中实施中鼻甲外侧壁切除的临床疗效显著,既不破坏鼻腔解剖结构,又保证了中鼻道的宽大,安全性较高,值得在临床推广应用。     

Impact of seston characteristics on qualitative particle selection sites and efficiencies in the pseudolamellibranch bivalve Crassostrea gigas

To date, knowledge of the qualitative particle selection sites and conditions in the widely-distributed bivalve Crassostrea gigas is incomplete, having focussed either on heterogeneous particles, or on particles intentionally too large to enter the gill principal filament tracts. We used endoscope-directed sampling and the intact diatom-empty, cleaned frustule approach to unambiguously establish qualitative selection sites and the influence of seston quality (varying proportions of intact diatoms and empty, cleaned frustules) and quantity (particle loads) on the degree of qualitative selection. Normally-feeding oysters were presented test mixtures of the naturally-occurring Actinoptychus senarius (small enough to enter the gill principal filaments), and the potential selection sites (gill: dorsal and ventral collecting tracts; labial palps: anteriorly-deposited pseudofaeces), were sampled for comparison with the proportions and concentrations of the ambient medium. Qualitative selection was demonstrated at both the gills and labial palps. Gill selection efficiency was shown to be directly proportional to seston quality and quantity, using a technique independant of pseudofeces mucus content. The oyster gill is thus able to increase ingested food quality when environmental food quality is low and / or when seston concentrations are high, which is typical of oyster habitats. Palp selection efficiency was directly proportional to seston quality, but at the highest concentration tested, no qualitative selection was observed on the labial palps, probably due to overload on these smaller organs. The partial functional redundancy of these key processing organs in heterorhabdic species such as oysters and scallops may enhance their success in high-turbidity habitats.