ORCID Profile
0000-0002-2196-8729
Current Organisations
Mayo Clinic
,
Capital Normal University
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Publisher: Mary Ann Liebert Inc
Date: 09-2015
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.JBIOMECH.2018.09.012
Abstract: Rodent models are commonly used to investigate tendon healing, with the biomechanical and structural properties of the healed tendons being important outcome measures. Tendon storage for later testing becomes necessary when performing large experiments with multiple time-points. However, it is unclear whether freezing rodent tendons affects their material properties. Thus the aim of this study was to determine whether freezing rat Achilles tendons affects their biomechanical or structural properties. Tendons were frozen at either -20 °C or -80 °C directly after harvesting, or tested when freshly harvested. Groups of tendons were subjected to several freeze-thaw cycles (1, 2, and 5) within 3 months, or frozen for 9 months, after which the tendons were subjected to biomechanical testing. Additionally, fresh and thawed tendons were compared morphologically, histologically and by transmission electron microscopy. No major differences in biomechanical properties were found between fresh tendons and those frozen once or twice at -20 °C or -80 °C. However, deterioration of tendon properties was found for 5-cycle groups and both long-term freezing groups after 9 months of freezing at -80 °C the tear resistance of the tendon was reduced from 125.4 ± 16.4N to 74.3 ± 18.4N (p = 0.0132). Moreover, tendons stored under these conditions showed major disruption of collagen fibrils when examined by transmission electron microscopy. When examined histologically, fresh s les exhibited the best cellularity and proteoglycan content of the enthesis. These properties were preserved better after freezing at -80 °C than after freezing at -20 °C, which resulted in markedly smaller chondrocytes and less proteoglycan content. Overall, the best preservation of histological integrity was seen with tendons frozen once at -80 °C. In conclusion, rat Achilles tendons can be frozen once or twice for short periods of time (up to 3 months) at -20 °C or -80 °C for later testing. However, freezing for 9 months at either -20 °C or -80 °C leads to deterioration of certain parameters.
Publisher: Oxford University Press (OUP)
Date: 03-02-2021
DOI: 10.1093/ZOOLINNEAN/ZLAA184
Abstract: Cantharidae is a erse group of soft-bodied beetles and frequently occurs in the Mid-Cretaceous (c. 99 Mya) amber of Myanmar. In the present paper, three new soldier beetles, Cretocantharis veda gen. & sp. nov., Palaeocantharispanna gen. & sp. nov. and Hukawngichthyurus maha sp. nov. are reported. A phylogenetic reconstruction of Cantharidae, including all extant subfamilies and tribes, corroborates a distinct lineage comprising cantharine-like cantharids from Burmese amber as sister to Silini (Silinae), revealing that the current subfamilial placement is probably inadequate. Together with our results and recent molecular phylogenetic frameworks, it reveals that subfamilies of Cantharidae evolved during the Cretaceous period and highlights a probable Gondwanan ancestry of main cantharid groups. Our topology also proposes that the systematically controversial tribe Tytthonyxini of Silinae constitutes an independent clade sister to Malthininae, rather than the component of Silinae. Furthermore, Archaeomalthodes rosetta, previously placed in Malthininae, is recovered as a member of Dysmorphocerinae, representing the oldest fossil record for this subfamily and enhancing the Gondwanan origin hypothesis of Burmese amber biota. The previous interpretation of reticulated elytra as a lycid-mimicry for the Cretaceous cantharid fossils and pleisiomorphy of Cantharidae are challenged and discussed.
Location: United States of America
No related grants have been discovered for Rodolfo De la Vega.