Objectives: Obstetric demands have long been considered in the evolution of the pelvis, yet consideration of the interaction of pregnancy, the pelvis, and the gastrointestinal tract (gut) is lacking. Here, we explore sex differences in the relationship of gut volume with body size and pelvic dimensions.
Materials And Methods: Computed tomography (CT) scans of living adult Homo sapiens (46 females and 42 males) were obtained to measure in vivo gut volume (GV) and to extract 3D models of the pelvis. We collected 19 3D landmarks from each pelvis model to acquire pelvic measurements. We used ordinary least squares regression to explore relationships between GV and body weight, stature, and linear pelvic dimensions.
Results: The gut-pelvis relationship differs between males and females. Females do not exhibit significant statistical correlations between GV and any variable tested. GV correlates with body size and pelvic outlet size in males. GV scales with negative allometry relative to body weight, stature, maximum bi-iliac breadth, inferior transverse outlet breadth, and bispinous distance in males.
Discussion: The lack of association between GV and body size in females may be due to limits imposed by the anticipation of accommodating a gravid uterus and/or the increased plasticity of the pelvis. The pattern of relationship between GV and the pelvic outlet suggests the role of the bony pelvis in supporting the adominal viscera in females may be small relative to its role in childbirth. We conclude that gut size inference in fossil hominins from skeletal proxies is limited and confounded by sexual dimorphism.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/ajpa.24084 | DOI Listing |
J Exp Biol
January 2025
Ornis italica, Rome, Italy.
Rapid reduction of body size in populations responding to global warming suggests the involvement of temperature-dependent physiological adjustments during growth, such as mitochondrial alterations, in the efficiency of producing metabolic energy, a process that is poorly explored, especially in endotherms. Here, we examined the mitochondrial metabolism and proteomic profile of red blood cells in relation to body size and cellular energetics in nestling shearwaters (Calonectris diomedea) developing at different natural temperatures. We found that nestlings of warmer nests had lighter bodies and smaller beaks at fledging.
View Article and Find Full Text PDFPLoS Biol
January 2025
Department of Biology, University of Washington, Seattle, Washington, United States of America.
Body size declines are a common response to warming via both plasticity and evolution, but variable size responses have been observed for terrestrial ectotherms. We investigate how temperature-dependent development and growth rates in ectothermic organisms induce variation in size responses. Leveraging long-term data for six montane grasshopper species spanning 1,768-3 901 m, we detect size shifts since ~1960 that depend on elevation and species' seasonal timing.
View Article and Find Full Text PDFCureus
December 2024
Internal Medicine, University of Alexandria, Alexandria, EGY.
Aim: Thyroid nodules, based on high-resolution ultrasonography (HRUS), are among the most common endocrine abnormalities that affect the general population because of their high estimated prevalence rates. Fine needle aspiration cytology (FNAC) is a safe, cost-effective modality to differentiate between benign and malignant thyroid nodules based on the Bethesda System for Reporting Thyroid Cytopathology (BSRTC), thus avoiding unnecessary surgery. However, categories III and IV of BSRTC remain a controversial issue in clinical practice, encompassing a wide range of risks of malignancy.
View Article and Find Full Text PDFJ Plankton Res
January 2025
Department of Biological Sciences, University of Quebec at Montréal (UQAM), C.P. 8888 Succ. Centre-Ville, Montréal, QC, H3P 3P8, Canada.
Cell size is a critical regulator of many metabolic processes in protists. We explored whether body size and abundances vary consistently in phytoplankton capable of both autotrophy and heterotrophy (mixoplankton) by manipulating environmental stoichiometric conditions in a mesocosm experiment. We applied two allochthonous subsidy treatments: high C: nutrient ratios (leaves) should favour bacterivory through phagotrophy, while low ratios (insects) should favour autotrophy.
View Article and Find Full Text PDFJBJS Essent Surg Tech
May 2024
Radboud University Medical Center, Nijmegen, The Netherlands.
Background: This video article describes the use of bone-anchored prostheses for patients with transtibial amputations, most often resulting from trauma, infection, or dysvascular disease. Large studies have shown that about half of all patients with a socket-suspended artificial limb experience limited mobility and limited prosthesis use because of socket-related problems. These problems occur at the socket-residual limb interface as a result of a painful and unstable connection, leading to an asymmetrical gait and subsequent pelvic and back pain.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!