Growth and molting in epizoic pedunculate barnacles genus Octolasmis (Crustacea: Thecostraca: Cirripedia: Thoracica)

Scanning electron microscopy, light microscopy, and histology were used to study growth in species of the pedunculate barnacle genus Octolasmis (O. angulata, O. cor, O. californiana, O. mülleri). These species are epizoic in the gill chamber of portunid crabs and have highly reduced capitular shell plates, with large areas of general cuticle in between. The external integument grows by means of a system of narrow growth zones, one encircling the peduncle and a Y-shaped system on either side of the capitulum. Growth is by a regular series of molts, but shedding of old cuticle and production of new layers is entirely restricted to the growth zones. Just prior to ecdysis, the new cuticle lies in a highly folded fashion beneath the old cuticle that is about to be shed. At ecdysis, the old cuticle breaks along the margins of the growth zones and the resulting scars remain as a system of "ecdysial lines" along either side of the zone. Once exposed after ecdysis, the new cuticle remains as a part of the permanent external integument. The growth zones divide the externa into five cuticular areas, two on the peduncle and three on the capitulum. The calcareous shell plates (carina, paired scuta, and, when present, paired terga) all lie within the capitular regions and the ecdysial lines pass across, not around, these mineralized areas. The number, relative spacing, and topology of the ecdysial lines form a record of the growth history of the specimen. These and other growth patterns demonstrate that size increase is due to the formation of new cuticle by molting in the growth zones, while expansion of the shell plates by mineralization follows only after production of the new cuticle. Thus, although specialized, growth in Octolasmis still complies with the general crustacean model, complicated only by the mineralization of parts of the capitular cuticle into shell plates. The results are compared with the very scarce information on molting in other barnacles. We argue that at least the circular peduncular growth zone is omnipresent in the Cirripedia Thoracica.     

Effect of DNA repair inhibitors on the induction and repair of bleomycin-induced chromosome damage.

The current status of the L5178Y/TK^+/-→TK^-/- mouse-lymphona mutagenicity assay is described. Dose-survival-mutagenic response data are shown for 43 chemicals. Mutagenicity and cytotoxicity in the presence or absence of non-induced and/or Aroclor-induced rat-liver S-9 are compared for most of these chemicals. 25 of these for which usable carcinogenicity data exist have been used to construct an approximately linear relationship between oncogenic potency in vivo and mutagenic potency in this system in vitro; linearity between these two endpoints extends over a greater than 100 000-fold range in potencies. Several carcinogens which are negative or difficult to detect in the standard Ames assay are mutagenic in this mammalian cell system. These include natulan, sodium saccharin (lot S-1022), p,p′-DDE (a metabolite of DDT), dimethylnitrosamine, diethylnitrosamine and diethylstilbestrol.     

Parallel plate equipment for preparation of uniform gel sheets

A method for the preparation of uniform gel-disks for enzyme and cell immobilisation, as well as for characterisation of gel mechanical stability, is described. The apparatus comprises a stainless steel base unit and glass parallel plates, designed to permit easy and fast production of multiple homogeneous gel sheets of variable thickness.     

Lateral plate evolution in the threespine stickleback: getting nowhere fast

Gasterosteus aculeatus is a small Holarctic fish with marine, anadromous, and freshwater populations. Marine and anadromous populations apparently have changed little in the past 10 million years and exhibit limited geographical variation. In contrast, freshwater isolates have been founded repeatedly by marine and anadromous populations, and post-glacial isolates have undergone extraordinary adaptive radiation. Stickleback traits that have diversified during post-glacial radiation, including the lateral plates (LP), can evolve substantially within decades after colonization of fresh water or when the environment (particularly predation regime) changes. Although highly divergent freshwater isolates of G. aculeatus have existed for at least 10 million years, they have rarely experienced sustained evolutionary divergence leading to formation of widespread, phenotypically distinct species. The paradox of rapid LP evolution without sustained divergence has resulted from selective extinction of highly divergent populations, because they are specialized for conditions in small, isolated habitats that tend to dry up within limited periods. Biological species of G. aculeatus may also evolve within decades, and are also prone to extinction because they are endemic to and specialized for small, ephemeral habitats. The high rate of evolution observed in contemporary threespine stickleback populations may not be unique to this species complex and has important implications for use of post-glacial populations in comparative studies, speciation rate, and discrimination of sympatric and allopatric speciation.     

一期外固定联合锁定钢板内固定术治疗 C 型 pilon 骨折的临床疗效

摘要 目的： 探讨外固定架联合锁定钢板分期治疗 C 型 pilon 骨折的临床疗效。 方法： 选取 2010 年 3 月至 2011 年 4 月在我院接受 治疗的 C 型 pilon 骨折患者 17 例。按照分期治疗的原则, 先行一期外固定架固定术, 待局部软组织恢复后切开复位, 再行锁定钢 板内固定术进行治疗, 术后对患者进行一年的随访, 定期检查患者的踝关节功能, 并借助影像学资料对临床疗效进行评价。结果： 全部患者获得随访, 平均愈合时间为(4.1± 1.6)月;平均 AOFAS 评分为(83.1± 12.4)分, 其中优 6 例(35.2 %), 良 8 例(47.1 %),一般 2 例(11.8 %), 差 1 例(5.9 %), 优良率为 82.4%; 术后 4 例患者出现出现轻度感染, 通过局部换药、 抗生素和钉道护理得到控制。结 论： 采用一期外固定联合锁定钢板内固定术分期治疗 C 型 pilon 骨折, 可以有效地提高治疗效果, 值得临床推广。     

MIPPO技术联合LCP钢板内固定治疗胫腓骨远端骨折的临床疗效观察

目的:探讨MIPPO技术联合LCP钢板内固定治疗胫腓骨远端骨折的临床疗效.方法:2009年8月～2012年6月,应用MIPPO技术结合LCP钢板内固定治疗胫腓骨远端骨折29例,男18例,女9例,年龄23～52岁,平均37岁;进行随访调查,对患者的骨折愈合情况、功能恢复情况及并发症等进行评估.结果:27例患者获得随访,随访时间10～24个月.27例患者骨折全部愈合,平均骨性愈合时间3～7个月,无钢板螺钉松动或断裂,无内固定失败者.2例患者发生与关节活动方向一致轻度成角畸形愈合(＜10°);4例患者患侧踝关节活动度较对侧减少;1例患者发生晚期感染,经治疗后痊愈.按Baird-Jackson踝关节功能评分标准,优21例,良4例,中1例,差1例,优良率92.6％.结论:MIPPO技术联合LCP治疗胫腓骨远端骨折具有创伤小、固定牢靠、术后恢复快、并发症少等优点,值得临床进一步研究和推广.     

桡骨远端骨折治疗的选择

目的:探讨不同类型的桡骨远端骨折的有效治疗方法。方法:分析106例桡骨远端骨折,分别采用闭合手法复位,切开复位或有限切开复位内固定方法,分别对骨折复位比较及功能评分。结果:完整随访106例桡骨远端骨折病例,随访时间3～21个月。对保守治疗组与手术治疗组进行骨折复位测定及改良Garland和Werley评分,A,B型骨折无显著性差异;C型骨折中,手术组明显优于保守治疗组。结论:对于C型骨折,建议行切开复位内固定治疗;对于A,B型需根据实际情况选择治疗方式。     

Abdominal plates,spiracles and sternites in the ventral mesosoma of embryos of the desert scorpion Paruroctonus mesaensis (Scorpiones,Vaejovidae)

Summary

The scanning electron microscope was used to study changes in the ventral mesosoma of the vaejovid scorpion, Paruroctonus mesaensis. Observations are compared with those from scorpion fossils. The oldest fossils are from the Silurian period; migration from water to land occurred in the Carboniferous and Permian periods. All recent scorpions are terrestrial with four pairs of booklungs and spiracles in mesosomal sternites. Ancient eurypterids and scorpions had flap-like abdominal plates attached to the ventral surface of five mesosomal segments. The abdominal plates were apparently an aquatic adaptation, and authors have described possible gill tissue in the chamber above. In scorpion embryos, rectangular (holostem) plate-like structures precede the formation of sternites in the ventral mesosoma. Transverse folds were seen in the space above the abdominal plates. The lack of elaborate gill-like structures here supports an earlier hypothesis that aquatic scorpions had other mesosomal respiratory sites (e.g., pectines), resulting in less reliance on respiratory tissues above the abdominal plates. Spiracles initially appear as round or ovoid patterns in the epidermis at the latero-posterior margins of the ventral plates. The booklung spiracles are positioned farther anterior in sternites, but the developmental sequence for this transition is still unclear and may occur later than the stages of this study. The abdominal plates lengthen and enlarge laterally and/or epidermis is added at the lateral edges so that broad, overlapping sternites eventually cover the ventral surface of the mesosoma.     

Chromatography process development in the quality by design paradigm I: Establishing a high‐throughput process development platform as a tool for estimating “characterization space” for an ion exchange chromatography step

This article describes the development of a high‐throughput process development (HTPD) platform for developing chromatography steps. An assessment of the platform as a tool for establishing the “characterization space” for an ion exchange chromatography step has been performed by using design of experiments. Case studies involving use of a biotech therapeutic, granulocyte colony‐stimulating factor have been used to demonstrate the performance of the platform. We discuss the various challenges that arise when working at such small volumes along with the solutions that we propose to alleviate these challenges to make the HTPD data suitable for empirical modeling. Further, we have also validated the scalability of this platform by comparing the results from the HTPD platform (2 and 6 μL resin volumes) against those obtained at the traditional laboratory scale (resin volume, 0.5 mL). We find that after integration of the proposed correction factors, the HTPD platform is capable of performing the process optimization studies at 170‐fold higher productivity. The platform is capable of providing semi‐quantitative assessment of the effects of the various input parameters under consideration. We think that platform such as the one presented is an excellent tool for examining the “characterization space” and reducing the extensive experimentation at the traditional lab scale that is otherwise required for establishing the “design space.” Thus, this platform will specifically aid in successful implementation of quality by design in biotech process development. This is especially significant in view of the constraints with respect to time and resources that the biopharma industry faces today. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29: 403–414, 2013