Browsing by Subject "Sex Characteristics"
Now showing 1 - 5 of 5
- Results Per Page
- Sort Options
Item Assessment of Sex Differences Following Repeated Mild Head Injuries(2022-05) Duggal, Aakaash; Schreihofer, Derek A.; Sumien, Nathalie; Luedtke, Robert R.There is limited information about sex differences in mRHI, despite some studies suggesting females participating in contact sports experience more head injuries than males. This study will test the hypothesis that mRHI will lead to more severe neurological deficits in female mice than in male mice. C57BL/6 female mice were assigned to sham and mRHI groups (n=30/group). Lightly anesthetized mice received 25 mild head injuries, once a day (M-F) over 5 weeks using a weight drop model that included a free fall with rotational injury. Acutely, mRHI female mice performed worse than sham injured mice on the balance beam (F (1,28) =4.309, P=0.0472) whereas there was no difference in males. 5 weeks and 15 weeks after injury mice underwent a 3-week series of behavioral tests. Both male and female mice in the mRHI groups performed significantly (T-test P< 0.01) worse on the Rotarod than uninjured controls. Only males in MWM showed significant impairment on memory for 5-week and significant impairment on spatial learning and memory for 15-week (Probe T-test P< 0.05). Only 15-week male mice showed deficits in elevated plus maze (EPM) (T-test P< 0.05). Acutely, female mice showed balance deficits that were not apparent in males. Fifteen weeks after mRHI, males no longer displayed deficits in the rotarod, but female mice continued to have a decrease in performance compared to controls (T-test, P<0.05). Unlike the males, female mice did not display any significant deficits in the MWM and EPM.Item Bacterial microbiomes of Ixodes scapularis ticks collected from Massachusetts and Texas, USA(BioMed Central Ltd., 2019-06-24) Thapa, Santosh; Zhang, Yan; Allen, Michael S.BACKGROUND: The blacklegged tick, Ixodes scapularis, is the primary vector of the Lyme disease spirochete Borrelia burgdorferi in North America. Though the tick is found across the eastern United States, Lyme disease is endemic to the northeast and upper midwest and rare or absent in the southern portion of the vector's range. In an effort to better understand the tick microbiome from diverse geographic and climatic regions, we analysed the bacterial community of 115 I. scapularis adults collected from vegetation in Texas and Massachusetts, representing extreme ends of the vector's range, by massively parallel sequencing of the 16S V4 rRNA gene. In addition, 7 female I. scapularis collected from dogs in Texas were included in the study. RESULTS: Male I. scapularis ticks had a more diverse bacterial microbiome in comparison to the female ticks. Rickettsia spp. dominated the microbiomes of field-collected female I. scapularis from both regions, as well as half of the males from Texas. In addition, the male and female ticks captured from Massachusetts contained high proportions of the pathogens Anaplasma and Borrelia, as well as the arthropod endosymbiont Wolbachia. None of these were found in libraries generated from ticks collected in Texas. Pseudomonas, Acinetobacter and Mycobacterium were significantly differently abundant (p < 0.05) between the male ticks from Massachusetts and Texas. Anaplasma and Borrelia were found in 15 and 63% of the 62 Massachusetts ticks, respectively, with a co-infection rate of 11%. Female ticks collected from Texas dogs were particularly diverse, and contained several genera including Rickettsia, Pseudomonas, Bradyrhizobium, Sediminibacterium, and Ralstonia. CONCLUSIONS: Our results indicate that the bacterial microbiomes of I. scapularis ticks vary by sex and geography, with significantly more diversity in male microbiomes compared to females. We found that sex plays a larger role than geography in shaping the composition/diversity of the I. scapularis microbiome, but that geography affects what additional taxa are represented (beyond Rickettsia) and whether pathogens are found. Furthermore, recent feeding may have a role in shaping the tick microbiome, as evident from a more complex bacterial community in female ticks from dogs compared to the wild-caught questing females. These findings may provide further insight into the differences in the ability of the ticks to acquire, maintain and transmit pathogens. Future studies on possible causes and consequences of these differences will shed additional light on tick microbiome biology and vector competence.Item Neuroprotective and neurotoxic outcomes of androgens and estrogens in an oxidative stress environment(BioMed Central Ltd., 2020-03-29) Duong, Phong; Tenkorang, Mavis A. A.; Trieu, Jenny; McCuiston, Clayton; Rybalchenko, Nataliya; Cunningham, Rebecca L.BACKGROUND: The role of sex hormones on cellular function is unclear. Studies show androgens and estrogens are protective in the CNS, whereas other studies found no effects or damaging effects. Furthermore, sex differences have been observed in multiple oxidative stress-associated CNS disorders, such as Alzheimer's disease, depression, and Parkinson's disease. The goal of this study is to examine the relationship between sex hormones (i.e., androgens and estrogens) and oxidative stress on cell viability. METHODS: N27 and PC12 neuronal and C6 glial phenotypic cell lines were used. N27 cells are female rat derived, whereas PC12 cells and C6 cells are male rat derived. These cells express estrogen receptors and the membrane-associated androgen receptor variant, AR45, but not the full-length androgen receptor. N27, PC12, and C6 cells were exposed to sex hormones either before or after an oxidative stressor to examine neuroprotective and neurotoxic properties, respectively. Estrogen receptor and androgen receptor inhibitors were used to determine the mechanisms mediating hormone-oxidative stress interactions on cell viability. Since the presence of AR45 in the human brain tissue was unknown, we examined the postmortem brain tissue from men and women for AR45 protein expression. RESULTS: Neither androgens nor estrogens were protective against subsequent oxidative stress insults in glial cells. However, these hormones exhibited neuroprotective properties in neuronal N27 and PC12 cells via the estrogen receptor. Interestingly, a window of opportunity exists for sex hormone neuroprotection, wherein temporary hormone deprivation blocked neuroprotection by sex hormones. However, if sex hormones are applied following an oxidative stressor, they exacerbated oxidative stress-induced cell loss in neuronal and glial cells. CONCLUSIONS: Sex hormone action on cell viability is dependent on the cellular environment. In healthy neuronal cells, sex hormones are protective against oxidative stress insults via the estrogen receptor, regardless of sex chromosome complement (XX, XY). However, in unhealthy (e.g., high oxidative stress) cells, sex hormones exacerbated oxidative stress-induced cell loss, regardless of cell type or sex chromosome complement. The non-genomic AR45 receptor, which is present in humans, mediated androgen's damaging effects, but it is unknown which receptor mediated estrogen's damaging effects. These differential effects of sex hormones that are dependent on the cellular environment, receptor profile, and cell type may mediate the observed sex differences in oxidative stress-associated CNS disorders.Item Sex differences in toll like receptor 7-mediated renal injury in a murine model of autoimmune-induced hypertension(2020-05) D'Souza, Bradley M.; Mathis, Keisa W.; Hodge, Lisa M.; Phillips, Nicole R.Systemic lupus erythematosus (SLE) is a female-dominant autoimmune disease associated with hypertension. We confirmed that SLE develops later in life in male vs. female SLE mice (35 vs. [less than] 30 weeks), yet both sexes develop hypertension by 35 weeks. Renal injury is a factor in hypertensive female SLE mice only, so we aimed to investigate this latent sex difference. We hypothesized that increased toll-like receptor 7 (TLR7), an immune mediator that instigates tissue damage, promotes renal injury in female SLE mice. We found that renal cortical expression of TLR7 was indeed higher in female SLE mice. In a follow-up study we found that renal hemodynamics were impaired in female SLE mice, but not males. Our data suggest that while the hypertension in female SLE mice may be due to renal mechanisms, hypertension in males is not. Future studies will dissect sex-specific factors that should be considered when treating hypertensive patients with underlying autoimmunity.Item Sexual Dimorphism in Permanent Human Dentition(2021-05) Aldeeb, Sara; Handler, Emma; Menegaz, Rachel A.; Maddux, Scott D.Sexual dimorphism refers to differences between males and females of the same species. A general pattern of sexual dimorphism is displayed in humans. Across mammalian populations, males generally have a larger body than females. Many studies have shown that, as body mass increases, tooth volume increases isometrically (Ungar, 2014). For example, on average, males have larger teeth than females (Schwartz and Dean, 2005). However, despite clear gross dental size differences, some studies have suggested that males and females also exhibit divergent quantities of enamel (Saunders et al., 2007). Females have been shown to have relatively thicker enamel, and a larger enamel cap area than males (Smith et al., 2006). This reveals an ambiguity. Although males possess overall larger teeth, studies suggest that male dental composition contains less relative enamel than would be expected given their tooth size. Similarly, females have been shown to exhibit smaller teeth than males, but a greater relative amount of enamel. This study has developed a methodological protocol for taking volumetric measures on dental microstructure using computed tomography (CT) scans. This protocol will help future studies evaluate the relative quantity of enamel and dentin in teeth. A better understanding of the volumetric differences in the dental microstructure is imperative to the understanding of dental sexual dimorphism. We examined the dental microstructure using 3D modeling from individuals in the Point Hope population. This population has been known to use their teeth as tools in several ways. We understand the microstructure of the dentition within the sample population may be impacted by some wear and use of dentition within this community. The dental microstructure was examined using 3D modelling in 14 individuals from a sample of the Point Hope population including eight adult females and six adult males of unknown age. Three hundred and twelve total teeth were examined. One hundred and eighty-six teeth came from female subjects, and one hundred twenty-six teeth came from males. The 3D models of the dentition and microstructure of enamel and dentin was generated using the software. Due to a small sample size, analysis of gross dental size and enamel volumes were performed using a one-tailed, non-parametric Mann-Whitney U-Test (a=0.10). Volumetric measurements of the total tooth volume, enamel volume, and dentin volume were recorded for each subject. Our results suggest that there are divergent quantities of enamel between males and females within the mandibular teeth. Specifically, the central incisors, lateral incisors, canines, first premolars, second premolars, and second molars within the mandible showed that there are statistical differences between sexes in dental composition. Males possessed a greater amount of enamel in their mandibular central incisors, lateral incisors, canines, first premolars, second premolars, and second molars. Additionally, the maxillary dentition also demonstrated notable statistical difference in enamel quantity within the second premolars between males and females. Males had a larger enamel quantity within their second molars than females. Males also demonstrated larger average total dental volume (345.59 mm3) than females (342.02 mm3). We have successfully generated a protocol in which future studies could quantify dental microstructure and add to the understanding of dental sexual dimorphism. Further research implementing this protocol for segmenting CT scans and utilizing the segmentation to gather volumetric measurements of dental microstructure should use higher resolution micro-CT scans and a larger sample population.