Search Results (534)

Background Sex disparity has been highlighted in personalized medicine for various human diseases including acute/chronic liver diseases. In the transplant community, greater graft failure risk in female-to-male liver transplantation (LT) has been repeatedly reported, and a recent study in living donor LT reported that the inferiority of female-to-male LT is shown only when donor age is ≤40 y. We aimed to analyze the United Network for Organ Sharing (UNOS) database to test if the poorer outcome of female-to-male LT changes by donor age of 40 y in deceased donor LT, as shown in living donor LT. Methods In this retrospective cohort study, 11,752 adult patients in the UNOS registry who underwent deceased donor LT between 2000–2023 were analyzed. Multivariable analysis was performed to adjust the effects from transplant years, graft ischemia time, disease severity, and others. The primary outcome was graft failure. Results Within the subgroup of recipients with ≤40 y donors, graft failure risk was significantly greater in female-to-male LT than others (vs. female-to-female, HR = 1.43 [1.16–1.76], p < 0.001; vs. male-to-female, HR = 1.46 [1.18–1.81], p < 0.001; vs. male-to-male, HR = 1.26 [1.16–1.49], p = 0.009). In contrast, within the subgroup of recipients with >40 y donors, the risk was comparable between female-to-male LT and other donor-recipient sex groups (vs. female-to-female, p = 0.907; vs. male-to-female, p = 0.781; vs. male-to-male, p = 0.937). We tested various cutoff donor ages and determined that 40 y is the best cutoff value to define the risk subgroup in female-to-male LT. Conclusions In the current study, we found that the sex disparity shown in living donor LT is also observed in deceased donor LT. That is, post-transplant graft failure risk was greater in female-to-male LT than other donor–recipient sex groups only when donor age was ≤40 y. In contrast, graft failure risk was comparable irrespective of donor-recipient sex combinations when donor age was >40 y. Full article

The successful transmission of Trypanosoma cruzi, the causative agent of Chagas disease, depends on intricate interactions with its insect vector. In Mexico, Meccus pallidipennis is a relevant triatomine species involved in the parasite’s life cycle. In the gut of these insects, the parasite moves from the anterior midgut (AMG) to the posterior midgut (PMG), where it multiplies. Finally, T. cruzi differentiates into its infective form by metacyclogenesis in the proctodeum or rectum (RE). This study aimed to characterize and compare the protein and glycoprotein profiles of the anterior midgut (AMG) and rectum (RE) of M. pallidipennis, and to assess their potential association with T. cruzi metacyclogenesis, with special attention to sex-specific differences. Insects were infected with the T. cruzi isolate ITRI/MX/12/MOR (Morelos). Protein profiles were analyzed by polyacrylamide gel electrophoresis, while glycoproteins were detected using ConA, WGA, and PNA lectins. The metacyclogenesis index was calculated for male and female triatomines. A lower overlap of protein fractions was found in the RE compared to the AMG between sexes, suggesting functional sexual dimorphism. Infected females showed greater diversity in glycoprotein patterns in the RE, potentially related to higher blood intake and parasite burden. The metacyclogenesis index was significantly higher in females than in males. These findings highlight sex-dependent differences in gut protein and glycoprotein profiles in M. pallidipennis, which may influence the efficiency of T. cruzi development within the vector. Further proteomic studies are needed to identify the molecular components involved and clarify their roles in parasite differentiation and suggest new targets for disrupting parasite transmission within the vector. Full article

The parasitoid wasp Dolichogenidea gelechiidivoris is a key koinobiont solitary endoparasitoid of the invasive agricultural pest Tuta absoluta. This study investigates both the morphological and molecular foundations of sex-specific olfactory differentiation in this species. Morphological analysis revealed that males possess significantly longer antennae (2880.8 ± 20.36 μm) than females (2137.23 ± 43.47 μm), demonstrating pronounced sexual dimorphism. Scanning electron microscopy identified similar sensilla types on both sexes, but differences existed in the length and diameter of specific sensilla. Transcriptomic analysis of adult antennae uncovered molecular differentiation, identifying 11 odorant-binding proteins (OBPs) and 20 odorant receptors (ORs), with 27 chemosensory genes upregulated in females and 4 enriched in males. Integrating morphological and molecular evidence demonstrates complementary sexual specialization in the olfactory apparatus of D. gelechiidivoris. Linking these findings to the potential functions of different sensilla types, as discussed in the context of prior research, provides crucial insights into the sex-specific use of volatile cues. These findings provide critical insights into the use of volatile signals in this highly relevant species for biological control targeting T. absoluta. Full article

Prolactin is a hormone with demonstrated roles in the brain, including neurogenesis, neuroprotection, learning, stress response or memory consolidation. To determine the prolactin expression in the rat hippocampus during aging and to resolve some controversies related to the presence of prolactin in the hippocampus, the aim of this study was to analyze whether changes occur in the expression of prolactin during different stages of life. To determine this, we designed an experimental study in which we analyzed the expression and location of prolactin in the rat hippocampus, Ammon’s horn and Dentate Gyrus, during different stages of life (prepubertal, postpubertal, young adult, adult and old) and checked if there are differences related to sex. Overall, the results obtained show that prolactin is present in the rat hippocampus and that prolactin is synthesized, as deduced from the findings obtained via ELISA, immunohistochemistry, qPCR and in situ hybridization. After analyzing the correlation between serum and hippocampal prolactin levels and comparing the amounts of Prl mRNA and the hormone, the results obtained suggest that hippocampal prolactin has a dual origin: local synthesis of the hormone and its passage from the blood. On the other hand, the amounts of prolactin and its mRNA in the hippocampus vary with sex and age, suggesting the existence of age-related sexual dimorphism. The results obtained suggest that hippocampal aging is related to a decrease in the hippocampal prolactin system, which helps to better understand brain aging. Full article

Although cranial growth has been extensively explored, forensic and biological anthropology lack a formal incorporation of how cranial growth processes impact the adult phenotype and downstream biological profile estimations. Objectives: This research uses an ontogenetic framework to identify when interlandmark distances (ILDs) stabilize during growth to reach adult levels of variation and to evaluate patterns of cranial sexual size dimorphism. Methods: Multivariate adaptive regression splines (MARS) were conducted on standardized cranial ILDs for 595 individuals from the Subadult Virtual Anthropology Database (SVAD) and the Forensic Data Bank (FDB) aged between birth and 25 years. Cross-Validated R-squared (CVRSq) values evaluated ILD variation explained by age while knot placements identified meaningful changes in ILD growth trajectories. Results: Results reveal the ages at which males and females reach craniometric maturity across splanchnocranium, neurocranium, basicranium and cross-regional ILDs. Changes in growth patterns observed here largely align with growth milestones of integrated soft tissue and skeletal structures as well as developmental milestones like puberty. Conclusions: Our findings highlight the variability in growth by sex and cranial region and move forensic anthropologists towards recognizing cranial growth as a mosaic, continuous process with overlap between subadults and adults rather than consistently approaching subadult and adult research separately. Full article

Background: Sexual dimorphism in Asian elephants (Elephas maximus) is evident in external features, but skeletal differences remain underexplored. This study aimed to examine the skull, scapula, and pelvis using traditional morphometric methods to assess sex-related variation. Methods: Eleven skeletal specimens were analyzed, including nine skulls, eleven pelves, and eighteen scapulae. Linear measurements were obtained using measuring tape and calipers. Statistical analyses included Mann–Whitney U tests, Pearson’s correlation, and logistic regression for sex prediction. Results: No significant differences were found in skull measurements between sexes. However, the pelvis and scapula exhibited notable variation. Significant pelvic parameters included pelvic girdle length (p = 0.024), symphysis length (p = 0.012), and pubis shaft perimeter (p = 0.048). Scapular differences were observed in diagonal breadth, mediolateral width, and spine length. Logistic regression using pelvic measurements yielded 100% accuracy for female classification and 66.67% for males, with an overall prediction accuracy of 90.91%. Conclusions: The pelvis demonstrated the highest reliability for sex determination. These findings enhance the anatomical understanding of Asian elephants and support applications in conservation, forensic science, and population studies. Future research with larger sample sizes and advanced imaging may improve the precision of morphometric sex prediction models. Full article

Geometric morphometrics is performed on different species in different contexts. Here, the aim was to investigate morphological differences in the head of the Sanmartinero Creole bovine to examine head shape variations between sexes using geometric morphometric methods. A sample of cranial pictures of 43 animals (13 males and 30 females) was obtained, and form (size + shape) was studied by means of geometric morphometric techniques using a set of 14 landmarks. This approach eliminated potential dietary effects, ensuring that the observed shape variations were primarily due to intrinsic morphological differences. Sexual dimorphism was found in form (for both size and shape) of the head of the Sanmartinero Creole bovine breed. Males had significantly larger heads based on centroid size (U = 714, p = 0.0004), confirming true sexual size differences, and Principal Component Analysis revealed overlapping head shapes with sexual dimorphism concentrated at midline sagittal landmarks (between the most rostral and caudal orbit points) and paired lateral points, indicating that males have broader and longer heads. The two evaluated characters (head size and shape) are of special interest for the conservation of the breed, especially in those cases whose objectives are to maintain the uniqueness, distinctiveness, and uniformity of the populations. This study analyzed animals subjected to the same feeding program, ensuring the elimination of additional variables. Full article

Sexual dimorphism is prevalent among animals, influencing both functional morphological traits and behavioral performances. In this study, we investigated the sexual differences in the morphological parameters of Kaloula borealis (Anura, Microhylidae) during the breeding season using 48 specimens. Our results reveal that among the 16 external morphological traits, females had significantly larger snout-vent length and eye diameter than males. The former presumably contributes to enhancing fertility, while the latter is associated with larger body size. Males exhibited significantly greater head width and thigh width than females, which may be related to accessing a wider range of food sources and enhancing their locomotor ability, respectively. Among the 32 appendicular muscles, 10 displayed significant sexual dimorphism in dry mass, suggesting divergent reproductive strategies between the sexes. Among the eight internal organs analyzed, males possessed significantly heavier hearts and lungs than females, which is likely an adaptation to higher metabolic demands and calling behavior. Collectively, our findings demonstrate that sex-specific differences in external morphology, muscle mass, and internal organ mass reflect distinct ecological and reproductive adaptations between males and females and contribute to the phenotypic diversities in Anura. Full article

The pelvis is the most dimorphic part of the human skeleton, primarily because of its involvement in the birth process. Many sexually dimorphic traits are concentrated in the coxal bones, which form the larger part of the birth canal. The present study aimed to assess the sex differences in coxal bone size and to develop machine learning (ML) models for sex estimation based on coxal bone measurements. The sample included abdominal computed tomography scans of 276 adult Bulgarians. Three-dimensional models of the pelves were generated using InVesalius. The three-dimensional coordinates of 34 landmarks located on the right and left coxal bones were collected in MeshLab. Based on the landmark coordinates, various measurements characterizing the coxal bones were calculated. The coxal bone dimensions were tested for significant differences with respect to sex, age, and laterality. Support Vector Machines and logistic regression were employed to train models for sex estimation. The results demonstrate strong sexual dimorphism in coxal bone dimensions along with some bilateral and age-related differences. The trained ML models classify male and female bones with very high accuracy, ranging between 95% and 100%. Full article

Preterm birth (PTB) refers to a labor before 37 gestational weeks. This is a major global contributor to neonatal morbidity and mortality. Although fetal sex is frequently treated as a confounding variable in PTB research, relatively few studies have conducted sex-stratified analyses to investigate how male and female fetuses may respond differently to various intrauterine exposures. This represents an underexplored area with important implications for understanding fetal sexual dimorphism-specific vulnerability to adverse pregnancy outcomes. Understanding the role of fetal sex differences in the pathophysiology of preterm birth (PTB) regarding processes such as inflammation, placental dysfunction, and oxidative stress is crucial. These delicate processes are tightly interrelated, but also independently contribute to pregnancy complications. Recognizing fetal sex as a biological variable for such processes is essential for improving mechanistic insight, providing refined predictive models. Full article

Previous research has demonstrated sex-specific differences in muscle cells regarding sex hormone release and steroidogenic enzyme expression after testosterone exposure. The present study aims to elucidate sex-related differences in intracellular processes involved in myogenesis and regeneration. Neonatal 46XX and 46XY human primary skeletal muscle cells were treated with increasing doses of testosterone (0.5, 2, 5, 10, 32, and 100 nM) for 24 h. The molecular pathways involved in muscle metabolism and growth, as well as the release of myokines involved in satellite cell activation, were analyzed using western blot, real-time PCR, and a Luminex assay. The unpaired Student’s t-test and one-way ANOVA for repeated measures were used to determine significant variations within and between groups. An increase in the expression and release of MYF6, IGF-I, IGF-II, and CXCL1, as well as a decrease in GM-CSF, IL-9, and IL-12, was observed in 46XX cells. Conversely, testosterone up-regulated GM-CSF and CXCL1 in 46XY cells but did not affect the release of the other myokines. Preferential activation of the MAPK pathway was observed in 46XX cells, while the PI3K/AKT pathway was preferentially activated in 46XY cells. In conclusion, our findings demonstrate differential responses to androgen exposure in 46XX and 46XY cells, resulting in the activation of muscle cell growth and energy metabolic pathways in a sex-specific manner. Full article

Sex determination is a fundamental component of forensic identification and medicolegal investigations. Several studies have investigated sexual dimorphism through mandibular osteometric measurements, including the position of anatomical foramina such as the mandibular and mental foramen (MF), reporting population-specific discrepancies. This study assessed the reliability and predictive ability of specific anthropometric mandibular measurements for sex estimation using three-dimensional (3D) cone beam computed tomography (CBCT) surface reconstructions. Methods: CBCT scans from 204 Greek individuals (18–70 years) were analyzed. Records were categorized by sex and age. Five linear measurements were traced on 3D reconstructions using ViewBox 4 software: projections of the inferior points of the right and left mental and mandibular foramina and the linear distance between mental foramina projections. A binary logistic regression (BLR) model was employed. All measurements showed statistically significant sex differences, with males presenting higher mean values. The final model achieved accuracy of 66.7% in sex prediction, with two vertical measurements—distances from the right mandibular foramen and the left mental foramen—identified as the strongest predictors of sex. The positions of the mandibular and mental foramina demonstrate sex-related dimorphism in this Greek sample, supporting their forensic relevance in population-specific applications. Full article

The crustacean Daphnia magna produces genetically identical females and males by parthenogenesis. Males are produced in response to environmental cues including crowding and lack of food. For male development, the DM-domain containing transcription factor Doublesex1 (DSX1) is expressed spatiotemporally in male-specific traits and orchestrates male trait formation in both somatic and gonadal tissues. However, it remains unknown how the dsx1 gene is silenced in females to avoid male trait development. Heterochromatin Protein 1 (HP1) plays a crucial role in epigenetic gene silencing during developmental processes. Here we report the identification of four HP1 orthologs in D. magna. None of these orthologs exhibited sexually dimorphic expression, and among them, HP1-1 was most abundantly expressed during embryogenesis. The knock-down of HP1-1 in female embryos led to the derepression of dsx1 in the male-specific traits, resulting in the development of male characteristics, such as the elongation of the first antennae. These results suggest that HP1-1 silences dsx1 for female development while environmental cues unlock this silencing to induce male production. We infer the HP1-dependent formation of a sex-specific chromatin structure on the dsx1 locus is a key process in the environmental sex determination of D. magna. Full article

Behavioral stress is a recognized triggering factor for systemic diseases, including psychiatric disorders. The stress response is subjected to circadian regulation and many factors shape the susceptibility to its maladaptive consequences, including the biological sex. Accordingly, circadian dysregulation of the stress response, often occurring in a sexually dimorphic manner, is typically associated with psychiatric disorders. However, the interaction between stress, sex, circadian phases, and behavior is still largely unknown. Here, we used the chronic restraint stress (CRS) model in male and female mice to assess the impact of sex and circadian phases on the behavioral consequences of chronic stress. Animals were stressed either in the light or dark phase, and anxious-/depressive-/anhedonic-like behaviors were assessed. Associated transcriptional changes in clock genes were measured in the prefrontal cortex. A significant interaction of stress, sex, and circadian phase was found in most of the parameters evaluated, with no behavioral response to stress in males stressed in the dark phase, and an exaggerated response in females stressed in the dark phase compared to the light phase. We also found some molecular changes in corticosterone serum levels and expression of clock genes in the prefrontal cortex. Full article

Urogenital cannulation is a traditional method used in aquaculture to achieve sexual differentiation, but it is considered invasive. Ultrasonography is a valuable non-invasive tool for determining sex and gonadal development in fish species like mullet (Mugil liza) and Brazilian sardine (Sardinella brasiliensis) that lack sexual dimorphism. The methodology involves emitting high-frequency sound waves (20 MHz to 20,000 MHz) above the human hearing range. These waves interact with the tissues of the body, producing echoes that are detected by a transducer. The echoes are then processed by computer graphics to generate detailed images of the internal structures of the organism. This allows for the determination of the sex of fish based on the sonographic features of the tissues. For instance, in male fish, hypoechogenic structures reflect fewer sound waves, leading to darker images. Conversely, in female fish, hyperechogenic tissues reflect more sound waves, resulting in lighter images. It is possible to classify the gonadal maturation stage based on differences in image texture. This non-invasive method eliminates the need for specimen dissection. It is especially valuable when the goal is to preserve the spawners’ life and integrity. This review emphasizes the application of this technology in aquaculture, specifically targeting fish from the Clupeidae and Mugilidae families. Full article