Morphometric modelling of ageing in the human pubic symphysis : sexual dimorphism in an Australian population

Despite the prominent use of the pubic symphysis for age estimation in forensic anthropology, little has been documented regarding the quantitative morphological and micro-architectural changes of this surface. Specifically, utilising post-mortem computed tomography data from a large, contemporary Australian adult population, this study aimed to evaluate sexual dimorphism in the morphology and bone composition of the symphyseal surface; and temporal characterisation of the pubic symphysis in individuals of advancing age. The sample consisted of multi-slice computed tomography (MSCT) scans of the pubic symphysis(slice thickness: 0.5 mm, overlap: 0.1 mm) of 200 individuals of Caucasian ancestry aged 15–70 years, obtained in 2011. Surface rendering reconstruction of the symphyseal surface was conducted in OsiriX1 (v.4.1) and quantitative analyses in Rapidform XOSTM and OsteomeasureTM. Morphometric variables including inter-pubic distance, surface area, circumference, maximum height and width of the symphyseal surface and micro-architectural assessment of cortical and trabecular bone compositions were quantified using novel automated engineering software capabilities. The major results of this study are correlated with the macroscopic ossification and degeneration pattern of the symphyseal surface, demonstrating significant age-related changes in the morphometric and bone tissue variables between 15 and 70 years. Regardless of sex, the overall dimensions of the symphyseal surface increased with age, coupled with a decrease in bone mass in the trabecular and cortical bone compartments. Significant differences between the ventral, dorsal and medial cortical surfaces were observed, which may be correlated to bone formation activity dependent on muscle activity and ligamentous attachments. Our study demonstrates significant sexual dimorphism at this site, with males exhibiting greater surface dimensions than females. These baseline results provide a detailed insight into the changes in the structure of the pubic symphysis with ageing and sexually dimorphic features associated with the cortical and trabecular bone profiles.

Evolution of sexual segregation in mammalian herbivores: kangaroos as marsupial models

Sexual segregation is best known in sexually dimorphic ungulates. Many hypotheses have been proposed to explain the evolution of sexual segregation in ungulates, but all are reducible to the influence of two factors: body size and sex-specific reproductive strategy. Definitive tests of these hypotheses are lacking in ungulates because these factors are confounded, all males being somewhat larger than females. Kangaroos represent a parallel radiation of terrestrial herbivores, but their populations are composed of a spectrum of adult body sizes, ranging from small males the same size as females to large males more than twice the size. We exploited this heteromorphism to assess the independent influences of size and sex in these ungulate analogues. We conducted a preliminary study of western grey kangaroos (Macropus fuliginosus) in north-western Victoria, Australia. Adult males predominately occupied grassland habitat, whereas females occurred mostly in lakebed, woodland and shrubland. Single-sex groups occurred more often than expected during the non-mating season. The diet of large males had the highest proportion of grass, and females had the least. These initial results indicate that both size and sex influence segregation in this species, confirming the worth of kangaroos as marsupial models for research into the evolution of sexual segregation.

Can an Ecdysiast Fag speak the voice of transgender? Phoenix (un)rising and the assumptions in Re Kevin revisited

"Each night the men look so surprised I change my sex before their eyes Tell me if you can What makes a man a man" - Charles Aznavour, ‘What makes a man a man (Comme ils disent)’. In (the few) Western jurisdictions in which marriage remains a forensic artefact constructed on the basis of a man|woman binary, the anatomical and heteronormative assumptions which underlie the construction of marriage remain as artificial constructs which do not map well (if indeed at all) to current social, or even medical, approaches to gender. In Re Kevin (Validity of Marriage of Transsexual) [2001] FamCA 1074, Justice Chisolm sought to recast the forensic ascription of sex against a broader set of criteria, expanding the range of sexually dimorphic anatomy used to determine sex for the purposes of marriage in Australia and incorporating observations of psycho-social gender-differentiation as factors relevant to the ultimate question for the Court — ‘What makes a man a man?’ Yet neither expansion is unproblematic. This article explores this fundamental forensic question against the background of Aznavour’s ‘Comme ils dissent’, in which the persona of un(e) stripteaseuse travesti struggles to answer precisely the same question. It concludes that Re Kevin might offer no more sophisticated an analysis of the lived reality of trans than Aznavour’s ecdysiast fag — not trans, but un travesti: "I shop and cook and sew a bit Though mum does too, I must admit I do it better."

Effect of deletion of Ghrelin-O-Acyltransferase on the pulsatile release of growth hormone in mice

Ghrelin, a gut hormone originating from the post-translational cleavage of preproghrelin, is the endogenous ligand of growth hormone secretagogue receptor 1a (GHS-R1a). Within the growth hormone (GH) axis, the biological activity of ghrelin requires octanoylation by ghrelin-O-acyltransferase (GOAT), conferring selective binding to the GHS-R1a receptor via acylated ghrelin. Complete loss of preproghrelin-derived signalling (through deletion of the Ghrl gene) contributes to a decline in peak GH release; however, the selective contribution of endogenous acyl-ghrelin to pulsatile GH release remains to be established. We assessed the pulsatile release of GH in ad lib. fed male germline goat−/− mice, extending measures to include mRNA for key hypothalamic regulators of GH release, and peripheral factors that are modulated relative to GH release. The amount of GH released was reduced in young goat−/− mice compared to age-matched wild-type mice, whereas pulse frequency and irregularity increased. Altered GH release did not coincide with alterations in hypothalamic Ghrh, Srif, Npy or Ghsr mRNA expression, or pituitary GH content, suggesting that loss of Goat does not compromise canonical mechanisms that contribute to pituitary GH production and release. Although loss of Goat resulted in an irregular pattern of GH release (characterised by an increase in the number of GH pulses observed during extended secretory events), this did not contribute to a change in the expression of sexually dimorphic GH-dependent liver genes. Of interest, circulating levels of insulin-like growth factor (IGF)-1 were elevated in goat−/− mice. This rise in circulating levels of IGF-1 was correlated with an increase in GH pulse frequency, suggesting that sustained or increased IGF-1 release in goat−/− mice may occur in response to altered GH release patterning. Our observations demonstrate that germline loss of Goat alters GH release and patterning. Although the biological relevance of altered GH secretory patterning remains unclear, we propose that this may contribute to sustained IGF-1 release and growth in goat−/− mice.