Phylogenetic and Biogeographic Analysis of Sphaerexochine Trilobites

BACKGROUND: Sphaerexochinae is a speciose and widely distributed group of cheirurid trilobites. Their temporal range extends from the earliest Ordovician through the Silurian, and they survived the end Ordovician mass extinction event (the second largest mass extinction in Earth history). Prior to this study, the individual evolutionary relationships within the group had yet to be determined utilizing rigorous phylogenetic methods. Understanding these evolutionary relationships is important for producing a stable classification of the group, and will be useful in elucidating the effects the end Ordovician mass extinction had on the evolutionary and biogeographic history of the group. METHODOLOGY/PRINCIPAL FINDINGS: Cladistic parsimony analysis of cheirurid trilobites assigned to the subfamily Sphaerexochinae was conducted to evaluate phylogenetic patterns and produce a hypothesis of relationship for the group. This study utilized the program TNT, and the analysis included thirty-one taxa and thirty-nine characters. The results of this analysis were then used in a Lieberman-modified Brooks Parsimony Analysis to analyze biogeographic patterns during the Ordovician-Silurian. CONCLUSIONS/SIGNIFICANCE: The genus Sphaerexochus was found to be monophyletic, consisting of two smaller clades (one composed entirely of Ordovician species and another composed of Silurian and Ordovician species). By contrast, the genus Kawina was found to be paraphyletic. It is a basal grade that also contains taxa formerly assigned to Cydonocephalus. Phylogenetic patterns suggest Sphaerexochinae is a relatively distinctive trilobite clade because it appears to have been largely unaffected by the end Ordovician mass extinction. Finally, the biogeographic analysis yields two major conclusions about Sphaerexochus biogeography: Bohemia and Avalonia were close enough during the Silurian to exchange taxa; and during the Ordovician there was dispersal between Eastern Laurentia and the Yangtze block (South China) and between Eastern Laurentia and Avalonia

POTENTIAL ANTI-TUMOR AGENTS .10. CYTOTOXIC NORDITERPENE DILACTONES OF PODOCARPUS-MILANJIANUS AND PODOCARPUS-SELLOWII

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Surgical Anatomy: Orchiectomy and Fertility Preservation Options

Simple bilateral orchiectomy provides an effective means of achieving castrate levels of testosterone, allowing transgender female patients to use a lower dose of estrogen and discontinue spironolactone. There is a current lack of evidence regarding the superiority of staged (early) orchiectomy—through an inguinal or scrotal approach—over single-stage orchiectomy and vaginoplasty. Therefore, the choice of technique and approach is based on patient preference and surgeon experience. Patients undergoing feminizing surgery should be informed about options for fertility preservation, including sperm cryopreservation, testicular sperm extraction, and testicular tissue cryopreservation

Prevalence of polycythaemia with different formulations of testosterone therapy in transmasculine individuals

Background: Masculinising hormone therapy with testosterone is used to align an individual's physical characteristics with their gender identity. Testosterone therapy is typically administered via intramuscular or transdermal routes and polycythaemia is the most common adverse event. Aims: To compare the risk of polycythaemia with different formulations of testosterone therapy in transmasculine individuals. Methods: A retrospective cross-sectional analysis was undertaken of transmasculine individuals at a primary and secondary care clinic in Melbourne, Australia. 180 individuals who were on testosterone therapy for >6 months were included. Groups included those receiving (1) intramuscular testosterone undecanoate (n = 125), (2) intramuscular testosterone enantate (n = 31), or (3) transdermal testosterone (n = 24). Outcome was prevalence of polycythaemia (defined as haematocrit >0.5). Results: Mean age was 28.4 (8.8) years with a median duration of testosterone therapy 37.7 (24.2) months. 27% were smokers. There was no difference between groups in serum total testosterone concentration measured. Whilst there was no difference between groups in haematocrit, there was a higher proportion of patients with polycythemia in those who were on intramuscular testosterone enantate (23.3%) than on transdermal testosterone (0%), p = 0.040. There was no statistically significant difference in polycythaemia between intramuscular testosterone undecanoate (15%) and transdermal, p = 0.066 nor between intramuscular testosterone enantate and undecanoate, p = 0.275. Conclusions: One in four individuals treated with intramuscular testosterone enantate and one in six treated with testosterone undecanoate had polycythaemia. No individual treated with transdermal testosterone had polycythaemia. This highlights the importance of regular monitoring of haematocrit in transmasculine individuals treated with testosterone and findings may inform treatment choicesBrendan J. Nolan, Shalem Y. Leemaqz, Olivia Ooi, Pauline Cundill, Nicholas Silberstein, Peter Locke, Mathis Grossmann, Jeffrey D. Zajac and Ada S. Cheun