内毒素致大鼠肺损伤时肺组织β受体的变化与膜磷脂代谢的关系

采用放射性配基结合分析法,现察内毒大致大鼠急性肺损伤时肺β－肾上腺素能受体（β－ＡＲ）的变化。分别用荧光偏振法和高效液相色谱测定肺组织细胞膜脂流动性和磷脂含量。结果显示：（１）静脉注射内毒素后４ｈ,大鼠肺β－ＡＲ的最大结合容量明显降低,较对照组减少４７％;（２）内毒素组肺膜脂流动性和磷脂含量均明显降低,同时伴有肺组织磷脂酶Ａ２（ＰＬＡ２）活性升高。提示：（１）β－ＡＲ下调导致其介导的功能减弱,在内毒素诱导的大鼠急性肺损伤发病机理中起一定作用;（２）ＰＬＡ２激活是膜磷脂减少的重要原因,后者可导致膜脂流动性降低,结果引起β－ＡＲ的侧向扩散和旋转运劝减弱,从而减少β－ＡＲ与配基结合的机率,出现β－ＡＫ下调。     

用荧光指示剂Fura－2测定正常和电刺激后蛙肌胞浆自由Ca~（2＋）浓度

蛙半腱肌肌束负载Ｆｕｒａ－２／ＡＭ后,可用荧光信号Ｆ３４０、３８０ｎｍ波长比值（Ｒ３４０／３８０）反映胞浆内游离Ｃａ２＋浓度（〔Ｃａ２＋〕）。利用这一技术,我们发现长时间电刺激后的骨骼肌〔Ｃａ２＋〕,高于未刺激肌,Ｒ３４０／３８０分别为１．４９±０．５４（ｎ＝１０）和１．０２±０．２６（ｎ＝１０）。加入Ｃａ２＋载体伊屋诺霉素（ｉｏｎｏｍｙｃｉｎ,１μｍｏｌ／Ｌ）后,正常肌与电刺激肌〔Ｃａ２＋〕,均上升,但刺激肌上升幅度低,持续时间短。说明电刺激至力竭后,细胞内有较多的Ｃａ２＋负载。增加细胞外Ｃａ２＋浓度至１５ｍｍｏｌ／Ｌ,〔Ｃａ２＋〕ｉ下降。而给予Ｎａ＋－Ｃａ２＋交换阻断剂奎尼丁（１０４ｍｏｌ／Ｌ）后,正常肌〔Ｃａ２＋〕ｉ上升,刺激肌〔Ｃａ２＋〕ｉ下降。结果提示：Ｎａ＋－Ｃａ２＋交换是正常骨胳肌外排Ｃａ２＋的途径之一;而长时间肌肉活动则可能使细胞膜Ｎａ＋－Ｃａ２＋交换方式改变,从而导致力竭肌〔Ｃａ２＋〕ｉ上升。     

Comparison of European and US biological indicators for ethylene oxide sterilization

Summary Biological indicators (BIs) are used to monitor ethylene oxide (EO) gas sterilization processes for medical devices. Several European and United States BIs for EO sterilization were evaluated for resistance according to both United States Pharmacopeia (USP) XXI and United Kingdom's (UK) tests for D-values. US BIs areB. subtilis var. niger spores on paper strips or disc carriers while European BIs use aluminum strips, quartz sand, or cotton yarn. Numerous BIs per run and runs per lot, as well as 2–3 different lots of BIs from each manufacturer, were examined. Both British and US BIs met their respective label claims for rates of inactivation when tested against British and USP EO test parameters, respectively. However, Danish BIs, on cotton yarn or quartz sand, were not inactivated following USP specifications during the exposure dwell times tested (600 mg L^–1 EO, 54°C, 60% RH, 0–110 min). The Danish BIs will require further testing in order for us to determine if theirB. subtilis spores are unusually resistant to EO or if the spore carrier substrates protect the spores from the sterilizing gas. In conclusion, the British and American BIs for EO sterilization are equivalent in resistance despite differences in carrier substrate, recovery conditions, calculation methods for D-values, and the labeled sterilization conditions for use.     

Design of a Robotized Magnetic Platform for Targeted Drug Delivery in the Cochlea

Inner ear disorders' treatment remains challenging due to anatomical barriers. Robotic assistance seems to be a promising approach to enhance inner ear treatments and, more particularly, lead to effective targeted drug delivery into the human cochlea. In this paper we present a combination of a micro-macro system that was designed and realized in order to efficiently control the navigation of magnetic nanoparticles in an open-loop scheme throughout the cochlea, considering that the magnetic particles cannot be located in real time.In order to respect the anatomical constraints, we established the characteristics that the new platform must present then proceeded to the design of the latter. The developed system is composed of a magnetic actuator that aims to guide nanoparticles into the cochlea. Mounted on a robotic manipulator, it ensures its positioning around the patient's head. The magnetic device integrates four parallelepiped-rectangle permanent magnets. Their arrangement in space, position and orientation, allows the creation of an area of convergence of magnetic forces where nanoparticles can be pushed/pulled to. To ensure the reachability of the desired orientations and positions, a 3 DOF robot based on a Remote Centre of Motion (RCM) mechanism was developed. It features three concurrent rotational joints that generate a spherical workspace around the head. The control of the latter is based on kinematic models.A prototype of this platform was realized to validate the actuation process. Both magnetic actuator and robotic manipulator were realized using an additive manufacturing approach. We also designed a virtual human head with a life-size cochlea inside. A laser was mounted on the end effector to track the positioning of the actuator. This permitted to experimentally prove the capacity of the robotic system to reach the desired positions and orientations in accordance with the medical needs.This promising robotic approach, makes it possible to overcome anatomical barriers and steer magnetic nanoparticles to a targeted location in the inner ear and, more precisely, inside the cochlea.     

A Physician's Perspective on the Incorporation of Pictograms as a Supplement to Medical Instructions in Chile: A Pilot Study

Introduction and objectivesCurrent models of health care are progressively migrating to more participatory models, where for treatment to achieve results that last over time, there must be effective communication between the patient, his or her caregivers, and health professionals. Although the use of pictograms in the context of medical instructions has been widely studied, in our country, there are no studies about their usefulness, or which set of symbols should be used by the systems. This work aims to present the first step towards the development of platforms that automatically suggest pictograms to supplement medical instructions for primary care settings in Chile.Materials and methodsIn this pilot study, we collected and analyzed the physicians' opinions on the selection of medical instructions that later will automatically be supplemented by the software that is under construction. We designed an expert validation survey using a set of 66 medical instructions with pictograms. This survey provided three rating options for each medical instruction: Not necessary (supplementing the instruction with a pictogram does not carry any value), Useful (supplementing the instruction with a pictogram may help patients to understand and remember the instruction), and Essential (supplementing the instruction with a pictogram is essential). Seventy-one physicians responded to the survey.Results22 out of 66 medical instructions were considered “essential” by >=51% of the experts, and 12 of the 66 were considered to be “useful but not essential” by >=51% of the experts.ConclusionResults of our survey validate the potential use of pictograms as a complement to better comprehension of medical instructions in our country.     

REVISING A CLASSIC BUTTERFLY MIMICRY SCENARIO: DEMONSTRATION OF MÜLLERIAN MIMICRY BETWEEN FLORIDA VICEROYS (LIMENITIS ARCHIPPUS FLORIDENSIS) AND QUEENS (DANAUS GILIPPUS BERENICE)

Batesian and Müllerian mimicry relationships differ greatly in terms of selective pressures affecting the participants; hence, accurately characterizing a mimetic interaction is a crucial prerequisite to understanding the selective milieux of model, mimic, and predator. Florida viceroy butterflies (Limenitis archippus floridensis) are conventionally characterized as palatable Batesian mimics of distasteful Florida queens (Danaus gilippus berenice). However, recent experiments indicate that both butterflies are moderately distasteful, suggesting they may be Müllerian comimics. To directly test whether the butterflies exemplify Müllerian mimicry, I performed two reciprocal experiments using red-winged blackbird predators. In Experiment 1, each of eight birds was exposed to a series of eight queens as “models,” then offered four choice trials involving a viceroy (the putative “mimic”) versus a novel alternative butterfly. If mimicry was effective, viceroys should be attacked less than alternatives. I also compared the birds' reactions to solo viceroy “mimics” offered before and after queen models, hypothesizing that attack rate on the viceroy would decrease after birds had been exposed to queen models. In Experiment 2, 12 birds were tested with viceroys as models and queens as putative mimics. The experiments revealed that (1) viceroys and queens offered as models were both moderately unpalatable (only 16% entirely eaten), (2) some birds apparently developed conditioned aversions to viceroy or queen models after only eight exposures, (3) in the subsequent choice trials, viceroy and queen “mimics” were attacked significantly less than alternatives, and (4) solo postmodel mimics were attacked significantly less than solo premodel mimics. Therefore, under these experimental conditions, sampled Florida viceroys and queens are comimics and exemplify Müllerian, not Batesian, mimicry. This compels a reassessment of selective forces affecting the butterflies and their predators, and sets the stage for a broader empirical investigation of the ecological and evolutionary dynamics of mimicry.     

DIEL CHANGES IN THE COMPOSITION OF PHOTOSYNTHETIC PIGMENTS AND CELLULAR CARBON AND NITROGEN IN CHATTONELLA ANTIQUA (RAPHIDOPHYCEAE)1

An axenic clonal culture of Chattonella antiqua (Hada) Ono was grown on a 12: 12 h LD cycle in a laboratory culture tank containing 1 m³ of f/2 medium. Diel changes in mean cell volume, cellular carbon (carbon content per cell), C/N ratio, cellular Chl a, Chl a/c ratio and carotenoid composition were observed. Mean cell volume and cellular C, N and pigments increased during the light period as a result of photosynthesis and decreased with increase of cell concentration by phased cell division during the dark period. These changes indicated that carbon assimilation and pigment synthesis occurred together during the light period. However, the patterns of increase were not the same since different diel patterns were also found in the ratios of C/N and chl a/c. Photosynthetic pigments were analyzed by reversed-phase high-performance liquid chromatography with ion-pairing solution. This analysis showed that the dominant carotenoids in C. antiqua were fucoxanthin, violaxanthin and β-carotene. Diel patterns of Chls a and c were similar to that of fucoxanthin but different from those of violaxanthin and β-carotene. The cellular contents of Chl a, fucoxanthin and carbon increased in a parallel manner during the light period. On the other hand, the increase of violaxanthin was restricted to only a few hours at the beginning of the light period during cell division cycles.     

Morphology and life history of Scytosiphon canaliculatus comb. nov. (Scytosiphonales,Phaeophyceae) from Japan*

Morphology of field material and life history in culture were studied in Scytosiphon canaliculatus (Setchell et Gardner) comb. nov. from northern Japan. Erect gametophytes of S. canaliculatus are cylindrical, tubular, up to 7 mm wide and 40 cm long, and without regular constrictions. S. canaliculatus has pronounced anisogamy and ascocysts accompanied with plurilocular gametangia. The life history of S. canaliculatus showed an alternation between erect gametophytes and crustose prostrate sporophytes bearing unilocular sporangia. Since field sporophytes of S. canaliculatus were found to be identical with Hapterophycus canaliculatus Setchell et Gardner (Ralfsiaceae, Phaeophyceae), it is proposed to transfer H. canaliculatus to the genus Scytosiphon. In the field, gametophytes with plurilocular gametangia appeared in spring and disappeared in summer. Sporophytes with unilocular sporangia were collected in late autumn and winter. Unilocular sporangia were produced at 15°C in short-day culture conditions and unispores developed into erect gametophytes at 5–15°C. It is suggested that the seasonal Occurrence of gametophytes in the field is due to the seasonal formation of unilocular sporangia, which is regulated by temperature and photoperiod.     

Comparative performance of benthic diatom indices used to assess river water quality

Grazer-periphyton interactions were investigated in 11 laboratory streams holding a range of densities of three herbivore taxa during a 32-d experiment. Effects of grazers on algae were strongest with Dicosmoecus gilvipes caddisflies, intermediate with Juga silicula snails, and weakest with Baetis spp. mayflies. Algal standing crop, export, and gross primary production declined logarithmically with increasing grazer density. Algal turnover rate, however, increased with grazer abundance. At high densities of all grazers, responses in most algal parameters converged, suggesting that high grazing pressure, regardless of taxon, will similarly affect periphyton. Growth of both Dicosmoecus caddisflies and Juga snails was density-dependent, with the highest growth rates occurring at the lowest densities. Caddisflies displayed high growth rates but low efficiency in resource use. Snails had lower growth rates but were more efficient in resource use. The coexistence of Dicosmoecus and Juga, or other competing herbivores, in natural streams may be related to these fundamental differences in life history strategies.Department of Fisheries and Wildlife