A RAPID, HIGHLY EFFICIENT METHOD FOR COLLECTING, FIXING, AND EMBEDDING PLANKTONIC AND OTHER SMALL CELLS FOR ELECTRON MICROSCOPY

A rapid, highly efficient method is described for fixation, dehydration, and embedding of small (e.g. planktonic) cells dispersed in large volumes of culture medium. The entire protocol, based on continuous filtration, can be completed within about an hour, and the yield of cells is very high. Fixation quality has been excellent with several different types of samples.     

Acupoint catgut embedding improves senescence in a rat model of ageing by regulating mitophagy via the PINK1 pathway

Ageing population is a tough task worldwide, and the aggravating trend of ageing population in China brings enormous pressure to healthcare system. Chinese acupuncture has shown definite anti-ageing effect as arthralgia relief, movement improvement, energy increase and immunity enhancement; however, the mechanisms underlying are far away from illumination. Increasing literature has highlighted the role of alterations in mitochondrial function as a potential central regulator in ageing biology; mitophagy plays a critical role in mitochondrial quality control. In the present study, we demonstrated that acupoint catgut embedding treatment ameliorated ageing-related alterations in appearance, muscle function and spatial memory in rats, reduced degenerated cells in hippocampus, and maintained relatively normal structures in the hippocampus tissue and neurons. These changes were proved to be associated with the regulation of mitochondrial function and autophagic activity. Furthermore, we investigated part of the molecular mechanisms and demonstrated that the PINK1 other than PINK1–Parkin signalling pathway involved in the effects of acupoint catgut embedding, and the imbalancement between mitochondrial fusion and fission and stimulation of mitochondrial biogenesis may aggravate or compensate for impaired mitochondria. The factors act downstream PINK, and the interaction between them for mitochondrial homeostasis in this process remains to be identified.     

The use of histology in the study of plant tissue culture systems—Some practical comments

Summary Histological methods have contributed significantly to our understanding of in vitro culture systems. A good histological study based on anatomical and histochemical changes provides insight into cellular processes and provides clues that allow for the proposal of hypotheses for further experimentation. This article serves to draw attention to the use of a histological approach to one’s experimental system. Some of the common mistakes in the handling and processing of explants are discussed. A protocol for the plastic embedding method is detailed.     

植物乳杆菌多孔淀粉直接包埋工艺的研究

利用多孔淀粉的吸附特性,将植物乳杆菌包埋于多孔淀粉内,通过测定多孔淀粉对植物乳杆菌的包埋率,研究菌体浓度、多孔淀粉添加量、振荡转速、包埋温度、pH值、时间对包埋率的影响,确定最适包埋条件。结果表明:菌体浓度10~8cfu/mL,多孔淀粉添加量为2%,pH 6.0、20℃,200 r/min振荡处理40 min,在此条件下包埋率为79.5%,对包埋后的菌体进行喷雾干燥试验,其存活率较未包埋的从0.35%提高到29.5%。     

Primary stability of tibial plateaus under dynamic compression-shear loading in human tibiae – Influence of keel length,cementation area and tibial stem

The objective of our study was to evaluate the impact of the tibial keel & stem length in surface cementation, of a full cemented keel and of an additional tibial stem on the primary stability of a posterior stabilised tibial plateau (VEGA® System Aesculap Tuttlingen, Germany) under dynamic compression-shear loading conditions in human tibiae.We performed the cemented tibial plateau implantations on 24 fresh-frozen human tibiae of a mean donor age of 70.7 years (range 47–97). The tibiae were divided into four groups of matched pairs based on comparable trabecular bone mineral density. To assess the primary stability under dynamic compression shear conditions, a 3D migration analysis of the tibial component relative to the bone based on displacements and deformations and an evaluation of the cement layer including penetration was performed by CT-based 3D segmentation.Within the tested implant fixation principles the mean load to failure of a 28 mm keel and a 12 mm stem (40 mm) was 4700 ± 1149 N and of a 28 mm keel length was 4560 ± 1429 N (p = 0.996), whereas the mean load to failure was 4920 ± 691 N in full cementation (p = 0.986) and 5580 ± 502 N with additional stem (p = 0.537), with no significant differences regarding the dynamic primary stability under dynamic compression-shear test conditions.From our observations, we conclude that there is no significant difference between a 40 mm and a 28 mm tibial keel & stem length and also between a surface and a full cementation in the effect on the primary stability of a posterior stabilised tibial plateau, in terms of failure load, migration characteristics and cement layer thickness including the penetration into the trabecular bone.     

Recruitment and diversification of an ecdysozoan family of neuropeptide hormones for black widow spider venom expression

Venoms have attracted enormous attention because of their potent physiological effects and dynamic evolution, including the convergent recruitment of homologous genes for venom expression. Here we provide novel evidence for the recruitment of genes from the Crustacean Hyperglycemic Hormone (CHH) and arthropod Ion Transport Peptide (ITP) superfamily for venom expression in black widow spiders. We characterized latrodectin peptides from venom gland cDNAs from the Western black widow spider (Latrodectus hesperus), the brown widow (Latrodectus geometricus) and cupboard spider (Steatoda grossa). Phylogenetic analyses of these sequences with homologs from other spider, scorpion and wasp venom cDNAs, as well as CHH/ITP neuropeptides, show latrodectins as derived members of the CHH/ITP superfamily. These analyses suggest that CHH/ITP homologs are more widespread in spider venoms, and were recruited for venom expression in two additional arthropod lineages. We also found that the latrodectin 2 gene and nearly all CHH/ITP genes include a phase 2 intron in the same position, supporting latrodectin's placement within the CHH/ITP superfamily. Evolutionary analyses of latrodectins suggest episodes of positive selection along some sequence lineages, and positive and purifying selection on specific codons, supporting its functional importance in widow venom. We consider how this improved understanding of latrodectin evolution informs functional hypotheses regarding its role in black widow venom as well as its potential convergent recruitment for venom expression across arthropods.     

锁定钢板内固定治疗复杂胫骨平台骨折的疗效观察

目的:探讨锁定钢板内固定治疗复杂胫骨平台骨折的临床疗效。方法:选择2011年2月~2013年2月期间我院收治的复杂胫骨平台骨折92例,按照数字随机法分为观察组(50例)和对照组(42例)。观察组采用锁定钢板内固定治疗;对照组采用传统钢板固定治疗,所有患者术后随访1年以上,观察两组患者临床疗效。结果:①两组患者均顺利完成手术,观察组住院时间、骨折愈合时间和完全负重时间显著低于对照组(P0.05)。②治疗后两组患者胫骨平台后倾角(Posterior tibial angle,PA)、膝关节活动度逐渐升高,内翻角(Tibial plateau angle,TPA)逐渐降低(P0.05),治疗6、12个月观察组PA、膝关节活动度显著高于对照组,TPA显著低于对照组(P0.05)。③所有患者术后随访1年,均获得满意随访。观察组膝总有效率为86.0%;对照组总有效率为66.7%,观察组膝关节总有效率显著高于对照组(P0.05)。结论:锁定钢板内固定治疗复杂胫骨平台骨折具有固定牢靠,骨折愈合时间短,愈合率高等特点,其临床效果较好。     

Pituitary Secretory Granule Topography: Influence of Different Electron Microscopic Preparation Procedures on the Surface of Epon Sections

Human, rat and mouse pituitary tissues have been examined electron microscopically in transmission (TEM), scanning-transmission (STEM) and scanning (SEM) modes for the surface appearance of the secretory granules in tissue sections. Cryofixed and cryosectioned tissue showed only slightly protruding granule profiles which had a smooth surface. Cryofixed, freeze-dried and Epon embedded pituitaries, on the other hand, demonstrated swollen and furrowed surfaces over the granules after contact with water. This topography could also be seen after glutaraldehyde fixation but less after post-fixation in OsO₄. The surface alterations in the sections of pituitary secretory granules are thought to be due to differences in the homogeneity of the resin infiltration, leaving resin-free openings where water can enter. It also seems probable that the Epon resin is more influenced by water than has been previously assumed, based on the findings of efficient elimination of osmium from the granules after incubation of tissue sections in water for only 10 min.     

A Mordanting Fixation for Intense Staining of Small Chromosomes

A combination iron-mordant fixative in which propionic acid is substituted for acetic acid has been found useful in preparing small plant chromosomes for carmine stained squashes. Propionic acid is better than acetic acid because it holds more iron in stable solution. The fixative is a 3:1 mixture of 95% alcohol and pure propionic acid which contains 400 mg. of Fe(OH)₃ per 100 ml. of propionic acid. The latter is previously prepared by dissolving the dry freshly prepared Fe(OH)₃ in it. To each 10 ml. vial of fixative is added a few drops of carmine stain. Standard aceto-carmine squashes of material fixed in this mixture show quick intense staining and are especially useful for differentiated chromosomes at mitotic prophase.     

Effects of Various Fixing and Storage Fluids on Starch in Sapwood

Wood material that is to be used for observation of starch content may be stored many months in several plant material fixatives, formalin-acetic-alcohol, formalin-propionic-alcohol, tertiary butyl alcohol, ethyl alcohol, and 5 and 10% aqueous formalin without any apparent deleterious effect on the starch granules Storage of wood in aqueous formalin solutions of 15% and higher concentrations caused starch granules to break down and disperse forming a coagulated mass, in which it was impossible to see the individual grains.