Effects Of Sex Research Articles

Do social cognitive factors influence final-year undergraduate students’ intentions to pursue advanced degrees? An examination of the moderating effect of sex

This study explores the factors influencing final-year undergraduate students’ intentions to pursue advanced degrees through the lens of social cognitive theory (SCT). In addition, it investigates the moderating effect of sex on the causal pathways in the proposed model. Using a quantitative cross-sectional survey design, 578 final-year undergraduate students from various degree programs participated in an online survey. The results revealed that outcome expectations and social support are significant predictors of intention, while intention itself predicts the implementation of intentions to pursue an advanced degree. However, self-efficacy was not found to influence intention, and sex did not moderate the hypothesized paths in the model. These findings suggest that SCT provides a useful and robust framework for understanding the factors shaping undergraduate students’ intentions to pursue advanced degrees, as evidenced by the high explanatory power of the structural model. The study also offers practical and theoretical implications, along with suggestions for future research.

A systematic literature review on the link between peer victimization and literacy during adolescence

Peer victimization and literacy failure are on the rise. Yet, there is little understanding of their interplay, particularly during adolescence–a period of heightened sensitivity to social–emotional and academic maladjustment. Guided by the Developmental Cascades Framework, this systematic literature review elucidated how peer victimization and literacy are directly and indirectly linked via negative behaviors, sex, and grade. A total of 21 studies were published between 1993 and 2022 that focused on typically developing 5th- to 8th-graders. Sample sizes ranged from 140 to 86,372 participants. Results indicated a bidirectional connection between increased peer victimization and poorer literacy. Preliminary evidence was found in support of an indirect link via internalizing behaviors, externalizing behaviors, and school engagement, but ambiguous support for the effect of sex. Taken together, adolescents who experience peer victimization are likely to struggle in literacy, as well as exhibit negative behaviors that may only serve to exacerbate this connection.

Ethylene oxide exposure, inflammatory indicators, and depressive symptoms: a cross-sectional study and mediation analysis based on a non-institutionalized American population.

Ethylene oxide (EO) is a volatile compound positively correlated with respiratory and cardiovascular diseases. Currently, evidence suggests that environmental exposure may contribute to depressive symptoms. This study evaluated the correlation between EO exposure and depressive symptoms and investigated whether inflammatory indicators had a mediation effect on this correlation. Patients were enrolled from the National Health and Nutrition Examination Survey during 2013-2016, and 2,764 (49.67% male and 50.33% female) participants were ultimately included. EO exposure was determined by measuring hemoglobin-EO adduct (Hb-EO) concentration due to its long half-life, which was log2-transformed. Depressive symptoms were assessed using the Patient Health Questionnaire-9. Multivariable logistic regression analysis was performed to identify any correlations before and after covariate adjustment. Sensitivity analysis, subgroup analyses, and interaction tests were performed to further evaluate identified correlations. Mediation analysis was conducted to reveal whether specific inflammatory indicators mediated the correlation. A high prevalence of depressive symptoms was observed in quartiles with increased levels of EO exposure, and male individuals exhibiting higher Hb-EO levels than female individuals. A positive correlation was observed between EO exposure and depressive symptoms (odds ratio [OR]: 1.439, 95% confidence interval [CI]: 1.310, 1.581), which remained stable even after covariate adjustment (OR: 1.332, 95% CI: 1.148, 1.545). Interaction tests showed significant effects of sex (p < 0.001) and thyroid diseases (p = 0.048) on this correlation. In the mediation analysis, white blood cell (p = 0.010) and neutrophil counts (p = 0.010) exerted a mediating effect, accounting for 13.6 and 11.9%, respectively. Increased exposure to EO is associated with an elevated risk of depressive symptoms, where white blood cell and neutrophil counts exert a significant mediating effect. Further prospective studies are required to investigate the potential link among EO, other environmental pollutants, and human mental health.

Effects of Sex and Kidney Mass on Podocyte Density in Rats

Effects of Sex and Kidney Mass on Podocyte Density in Rats

Differences in memory performance: The effects of sex and reproductive experience on object recognition memory in high- and low-yawning Sprague‒Dawley rats

The novel object recognition (NOR) test is an efficient way to measure nonspatial memory in rodents. The NOR performance of female and male rats is sexually dimorphic because memory performance is better in the former than in the latter. In females, maternal experience enhances spatial memory. We used the NOR test to evaluate short- and long-term recognition memory in both sexes in the high- and low-yawning sublines of rats (HY and LY, respectively), which were generated via a strict inbreeding process from the Sprague‒Dawley (SD) strain for more than ninety generations. Additionally, we evaluated the effect of maternal experience using nulliparous, primiparous, biparous, and multiparous HY, LY and SD dams. Our results revealed that LY rats presented less thigmotaxis, with lower central square crosses and more vertical exploration in the open-field arena, suggesting that they experienced anxiety. Additionally, LY males performed significantly better than LY females in short- and long-term NOR memory, and LY males performed significantly better than SD rats did. Among females, two maternal experiences negatively affected short-term memory in the LY and HY sublines with respect to primiparous dams, and HY dams had better memory performance in the NOR test than did SD dams. Our findings suggest that the yawning sublines are suitable for studying the neurobiological basis of different memory processes under different endocrine conditions in highly inbred groups of rats.

Determinants of HBeAg loss during follow-up of a multiethnic pediatric cohort.

Hepatitis B e antigen (HBeAg) loss is a key event in the natural history of chronic hepatitis B virus infection. The rate and determinants of HBeAg loss depend upon cohort characteristics at baseline. Few studies have examined the age-dependent rate, and none have examined the effect of patient sex and ethnicity on the age-dependant rate. The study of age-dependent rates requires the identification and long-term follow-up of a pediatric cohort. We have studied the age-dependent rate of HBeAg loss, and the rate of HBeAg loss measured from baseline, in a multi-ethnic cohort of 454 pediatric patients. During observation, HBeAg loss was observed in 121/303 (39.9%) HBeAg-positive patients. The rate of HBeAg loss was greater in the second versus the first and third decades of life. The age-related rate of HBeAg loss was clearly affected by patient sex and ethnicity, with earlier loss observed for males and for White versus both South Asian and Chinese ethnicities. When measured from baseline, Chinese patients had a slower rate of HBeAg loss in comparison with White patients. In multivariate analysis of HBeAg loss during prolonged follow-up, male sex, older age, and White ethnicity were associated with HBeAg loss, but antiviral treatment was not.

Resistance and resilience to tau pathology in Alzheimer's disease: Effects of age, sex, and APOE alleles.

Neurofibrillary tangles (NFTs), a hallmark of tau pathology in Alzheimer's disease (AD), accumulate in the aging brain. However, some individuals remain cognitively intact despite high Braak (III-VI) stages, which characterize NFTs' accumulation. We studied resistance and resilience to tau pathology by assessing Braak stages based on apolipoprotein E (APOE) alleles, sex, and age in a sample of 1932 cognitively intact individuals of European ancestry from the Alzheimer's Disease Sequencing Project (ADSP). Resistance, characterized by low (0-II) Braak stages, was observed in men and women younger than 85 years of age. Resilience, indicated by high (III-VI) Braak stages, increased significantly with age in both men and women for each APOE allele. It became more pronounced, with the proportion of high Braak stages exceeding 50% at 85 years and older in women, irrespective of the APOE allele. The identification of factors underlying resistance and resilience against AD-related pathologies is essential for promoting cognitively healthy aging. We investigated cognitive resistance and resilience to tau pathology in Alzheimer's disease (AD).This study included individuals who were not diagnosed with AD.Braak stages 0-II and III-VI were considered as a measure of resistance and resilience, respectively.Resistance was stronger at ages younger than 85 years in non-carriers of the apolipoprotein E (APOE) ε4 allele.Resilience increased with age for each APOE allele independently of sex.At age 85 years and older, high resilience(>50%) was observed in women regardless of the APOE allele.

Normative data for the lateralization task in the assessment of intranasal trigeminal function

To provide normative data for the lateralization task in the assessment of intranasal trigeminal function, as well as to investigate potential effects of age, sex and olfactory function. The lateralization task using eucalyptus as target stimulus was performed to assess intranasal trigeminal function. Data were collected from: 360 healthy adult participants (mean age 37.5±17.4) for the 40-trial version; 284 participants (mean age 32.6±14.1) for the 20-trial version; and 418 participants (mean age 42.6±15.6) for the 10-trial version. The "Sniffin' Sticks" test was used to measure olfactory function. The mean scores were 35.46±4.50 for the 40-trial version, 15.64±3.65 for the 20-trial version, and 8.14±2.16 for the 10-trial version. In the reference group aged 18-25 years, the 10th percentiles were 33 for the 40-trial version, 11 for the 20-trial version, and 6 for the 10-trial version. Significant effects of age and odor discrimination score were observed on lateralization performance. We provide reference scores for the lateralization task, in large sample of healthy participants. Among the three examined tasks (40, 20 and 10), the 40-trial task yielded the most reliable information. For the 40-trial version, scores equal or higher to 33 points indicate a normal lateralization ability, whereas scores between 27 and 32 may warrant further assessment. Scores below 27 possibly point towards a decreased trigeminal function. The lateralization task serves as surrogate marker of intranasal trigeminal functions and further studies with pathological cases are needed to explore its clinical usefulness.

An inducible model for medial calcification based on matrix Gla protein deficiency

Calcific deposits in the arterial media have been associated with a number of metabolic and genetic disorders including diabetes, chronic kidney disease and generalized arterial calcification of infancy. The loss of Matrix Gla protein (MGP) leads to medial elastic lamina calcification (elastocalcinosis) in both humans and animal models. While MGP-deficient (Mgp-/-) mice have been used as a reliable model to study medial elastocalcinosis, these mice are difficult to maintain because of their fragility. Also, these mice are unsuitable for long-term calcification studies in relation to age and sex as most often they die prematurely. In order to circumvent these problems we generated Mgp-/-;ApoE-FGF23 mice, which in addition to the ablation of Mgp alleles, carries a transgene expressing the phosphaturic hormone FGF23. Increased FGF23 levels in the circulation and ensuing hypophosphatemia in these mice lead to a complete prevention of medial calcification until late adulthood. Interestingly, upon feeding a high phosphorus diet for 10 days, we were able to induce medial calcification in 3-week-old Mgp-/-;ApoE-FGF23 mice. Our mineral analyses showed that the calcific deposits in these mice were Our mineral analyses showed that the Ca/P % in the calcific deposits in these mice were comparable to that of 5-week-old Mgp-/- mice although the level of crystallinity differed. The aorta explants from Mgp-/-;ApoE-FGF23 mice resulted in elastocalcinosis in the presence of 2mM phosphate in the culture medium which was completely prevented by pyrophosphate analogue alendronate. Mgp-/-;ApoE-FGF23 mice will be suitable for future in vivo or ex vivo studies examining the effects of age, sex and mineralization inhibitors on medial elastocalcinosis.

Sex differences in COVID-19 vaccine confidence in people living with HIV in Canada

BackgroundUnderstanding the roots of vaccine confidence in vulnerable populations, such as persons living with HIV (PLWH), is important to facilitate vaccine uptake, thus mitigating infection and spread of vaccine-preventable infectious diseases. In an online survey of PLWH conducted in Canada during winter 2022 (AIDS and Behav 2023), we reported that the overall COVID-19 vaccination uptake rate in PLWH was similar by sex. Here, we examined attitudes and beliefs towards vaccination against COVID-19 based on sex. MethodsBetween February and May 2022, PLWH across Canada were recruited via social media and community-based organizations to complete an online survey consisting of a modified Vaccine Hesitancy Scale (VHS) questionnaire with items from the National Advisory Committee on Immunization Acceptability Matrix. Descriptive statistics were used to summarize participant characteristics and responses to the VHS questionnaire by biological sex. The effect of biological sex on total VHS score, two subscales (“lack of confidence” and “perceived risk”) was assessed separately by linear regression adjusting for other key baseline variables. ResultsOf 259 PLWH, 69 (27 %) were females and 189 (73 %) were males. Sixty-six (26 %) of participants self-identified as a woman, 163(63 %) as a man and 28(11 %) as trans/two-spirited/queer/non-binary/agender/other. The mean age (SD) was 47 ± 14 years. Females were less likely to believe that COVID-19 vaccination was: important for his/her own health (71 % vs. 86 %); a good way to protect themselves from infection (68 % vs. 86 %); that getting the COVID-19 vaccine was important for the health of others in his/her community (78 % vs. 91 %); believed recommendations by their doctor/health care provider about COVID-19 vaccines (78 % vs. 88 %); that information about COVID-19 vaccines from public health officials was reliable and trustworthy (56 % vs. 75 % vs); COVID-19 vaccines are effective in preventing COVID-19 infections (61 % vs. 82 %) and that all COVID-19 vaccines offered by government programs in their communities were important for good health (70 % vs. 87 %). Although more males than females felt that new vaccines generally carry more risks than older vaccines (19 % vs 16 %,), fewer males than females endorsed concern about serious side effects of COVID-19 vaccines (33 % vs 45 %).The linear regression model showed females had a significantly higher VHS total score than males (adjusted mean difference 0.38; 95 % confidence interval (CI) 0.13–0.64; p = 0.004), indicating greater COVID-19 vaccine hesitancy among females. It was observed that females had a greater “lack of confidence in vaccines” score than males (adjusted mean difference 0.43; 95 % CI 0.14–0.73; p = 0.004). We did not observe a significant difference in “perceived risk in vaccines” between males and females (adjusted mean difference 0.20; 95 % CI −0.07–0.46; p = 0.1). The inadequate number of participants self-identifying as different from biological sex at birth prevented us from analyzing the VHS score based on gender identity. ConclusionsAmong PLWH, females showed greater COVID-19 vaccine hesitancy than males. Specifically, compared with males, females had a higher level of lack of confidence in vaccines. Fewer females than males believed that COVID-19 vaccines had health benefits at both the personal and societal level and that recommendations made by their doctor/health care provider and public health officials are reliable and trustworthy. Further investigation into reasons for this difference in opinion still needs to be elucidated. Educational interventions targeted toward females living with HIV are especially needed to increase confidence in vaccination.

Associations of Sedentary Behavior with Risks of Cardiovascular Disease Events among Chinese Adults.

Evidence regarding the modification effects of age, sex, ethnicity, socioeconomic status, or weight status on the associations of sedentary behavior (SB) with cardiovascular diseases (CVDs) is limited. Moreover, the mechanisms for the associations also remain unclear. We aimed to investigate the possible influence of these factors on the associations of SB with CVD events and whether the associations are mediated by metabolic phenotypes. This study included 42,619 participants aged 20-74 years, recruited from the Shanghai Suburban Adult Cohort and Biobank study. SB was assessed at baseline and integrated with health information systems to predict future CVD events. Cox proportional hazards models, interaction analyses, restricted cubic splines and causal mediation analyses were used for assessments. Compared to those with ＜3 h/d sedentary time, participants having SB ≥ 5 h/d had significantly higher risks of CVD (HR[95%CI]: 1.27[1.12-1.44]), coronary heart disease (CHD, 1.35[1.14-1.60]), and ischemic stroke (IS, 1.30[1.06-1.60]). The association of CHD was more pronounced in the retired individuals than their counterparts (1.45[1.20-1.76] versus 1.06[0.74-1.52], pinteraction=0.046). When SB was expressed as a continuous variable, a 1 h/d increment in SB was positively associated with risks of CVD (1.03[1.01-1.05]), CHD (1.04[1.01-1.07]), and IS (1.05[1.01-1.08]). High-density lipoprotein cholesterol (HDL-C, proportion mediated: 12.54%, 12.23%, and 11.36%, all p＜0.001), followed by triglyceride (TG, 5.28%, 4.77%, and 4.86%, all p＜0.01) and serum uric acid (SUA, 3.64%, 4.24%, and 2.29%, all p＜0.05) were major mediators through metabolic phenotypes. Higher SB was associated with elevated risks of CVD events. The detrimental effect of SB on CHD risk was more pronounced among retired individuals. Moreover, HDL-C, TG and SUA partially mediated the relationships between SB and CVD events. Our findings may have implications for preventing and controlling CVD associated with SB.

The Metabolic Cost Of Breathing During Exercise: Effects Of Age And Sex

The Metabolic Cost Of Breathing During Exercise: Effects Of Age And Sex

Effects Of New Zealand Blackcurrant, Body Composition, And Sex On Fat Oxidation During Exercise

Effects Of New Zealand Blackcurrant, Body Composition, And Sex On Fat Oxidation During Exercise

Effect of older age and/or ACL injury on the dose–response relationship between ambulatory load magnitude and immediate load-induced change in serum cartilage oligomeric matrix protein

PurposeThis study aimed to assess the influence of older vs. younger age and previous anterior cruciate ligament (ACL) injury on resting serum cartilage oligomeric matrix protein (sCOMP[tpre]) concentration, on immediate load-induced sCOMP kinetics after a 30-min treadmill walking stress (∆_sCOMP[tpost]), and on the dose–response relationship between ambulatory load magnitude and ∆_sCOMP(tpost). MethodsA total of 85 participants were recruited in 4 groups (20–30 years: 24 healthy, 23 ACL-injured; 40–60 years: 23 healthy, 15 ACL-injured). Blood samples were collected immediately before and after a walking stress at 80%, 100%, or 120% bodyweight (BW) on 3 test days and analyzed for sCOMP concentration. Linear models were used to estimate the effect of age, knee status (unilateral ACL injury, 2–10 years prior), and sex on sCOMP(tpre), ∆_sCOMP(tpost)), and the dose–response between ambulatory load magnitude and ∆_sCOMP(tpost). ResultsWe found that sCOMP(tpre) was 21% higher in older than younger participants (p < 0.001) but did not differ between ACL-injured and healthy participants (p = 0.632). Also, ∆_sCOMP(tpost) was 19% lower in older than younger participants (p = 0.030) and increased with body mass index (p < 0.001), sCOMP(tpre) (p = 0.008), and with 120%BW (p < 0.001), independent of age, ACL injury, or sex. ConclusionAge but not prior ACL injury influences resting sCOMP and load-induced sCOMP. The dose–response relationship between ambulatory load magnitude and load-induced sCOMP changes is not affected by age, ACL injury, or sex. A better understanding of systemic sCOMP and the role of its mechanoresponse for the understanding of osteoarthritis pathophysiology and monitoring intervention efficacy may require knowledge of individual cartilage composition and tissue-level loading parameters.

Histone deacetylase expression following cisplatin-induced acute kidney injury in male and female mice.

The chemotherapeutic agent cisplatin accumulates in the kidneys, leading to acute kidney injury (AKI). Preclinical and clinical studies have demonstrated sex-dependent outcomes of cisplatin-AKI. Deranged histone deacetylase (HDAC) activity is hypothesized to promote the pathogenesis of male murine cisplatin-AKI; however, it is unknown whether there are sex differences in the kidney HDACs. We hypothesized that there would be sex-specific Hdac expression, localization, or enzymatic activity, which may explain sexual dimorphic responses to cisplatin-AKI. In normal human kidney RNA samples, HDAC10 was significantly greater in the kidneys of women compared with men, whereas HDAC1, HDAC6, HDAC10, and HDAC11 were differentially expressed between the kidney cortex and medulla, regardless of sex. In a murine model of cisplatin-AKI (3 days after a 15 mg/kg injection), we found few sex- or cisplatin-related differences in Hdac kidney transcripts among the mice. Although Hdac9 was significantly greater in female mice compared with male mice, HDAC9 protein localization did not differ. Hdac7 transcripts were greater in the inner medulla of cisplatin-AKI mice, regardless of sex, and this agreed with a greater HDAC7 abundance. HDAC activity within the cortex, outer medulla, and inner medulla was significantly lower in cisplatin-AKI mice but did not differ between the sexes. In agreement with these findings, a class I HDAC inhibitor did not improve kidney injury or function. In conclusion, even though cisplatin-AKI was evident and there were transcript level differences among the different kidney regions in this model, there were few sex- or cisplatin-dependent effects on kidney HDAC localization or activity.NEW & NOTEWORTHY Kidney histone deacetylases (HDACs) are abundant in male and female mice, and the inner medulla has the greatest HDAC activity. A low dose of cisplatin caused acute kidney injury (AKI) in these mice, but there were few changes in kidney HDACs at the RNA/protein/activity level. A class I HDAC inhibitor failed to improve AKI outcomes. Defining the HDAC isoform, cellular source, and interventional timing is necessary to determine whether HDAC inhibition is a therapeutic strategy to prevent cisplatin-AKI in both sexes.

Using Bayesian Analysis to determine the effect of sex on sensorimotor acuity in athletes

Using Bayesian Analysis to determine the effect of sex on sensorimotor acuity in athletes

Sex Differences in Skeletal Muscle Pathology in Patients With Heart Failure and Reduced Ejection Fraction.

Women with heart failure and reduced ejection fraction (HFrEF) have greater symptoms and a lower quality of life compared with men; however, the role of noncardiac mechanisms remains poorly resolved. We hypothesized that differences in skeletal muscle pathology between men and women with HFrEF may explain clinical heterogeneity. Muscle biopsies from both men (n=22) and women (n=16) with moderate HFrEF (New York Heart Association classes I-III) and age- and sex-matched controls (n=18 and n=16, respectively) underwent transcriptomics (RNA-sequencing), myofiber structural imaging (histology), and molecular signaling analysis (gene/protein expression), with serum inflammatory profiles analyzed (enzyme-linked immunosorbent assay). Two-way ANOVA was conducted (interaction sex and condition). RNA-sequencing identified 5629 differentially expressed genes between men and women with HFrEF, with upregulated terms for catabolism and downregulated terms for mitochondria in men. mRNA expression confirmed an effect of sex (P<0.05) on proatrophic genes related to ubiquitin proteasome, autophagy, and myostatin systems (higher in all men versus all women), whereas proanabolic IGF1 expression was higher (P<0.05) in women with HFrEF only. Structurally, women compared with men with HFrEF showed a pro-oxidative phenotype, with smaller but higher numbers of type I fibers, alongside higher muscle capillarity (Pinteraction<0.05) and higher type I fiber areal density (Pinteraction<0.05). Differences in gene/protein expression of regulators of muscle phenotype were detected between sexes, including HIF1α, ESR1, VEGF (vascular endothelial growth factor), and PGC1α expression (P<0.05), and for upstream circulating factors, including VEGF, IL (interleukin)-6, and IL-8 (P<0.05). Sex differences in muscle pathology in HFrEF exist, with men showing greater abnormalities compared with women related to the transcriptome, fiber phenotype, capillarity, and circulating factors. These preliminary data question whether muscle pathology is a primary mechanism contributing to greater symptoms in women with HFrEF and highlight the need for further investigation.

Insights into sex differences in perioperative outcomes of non-small cell lung cancer patients.

The appreciation of sex differences is substantial for precise cancer management. Surgery is the main treatment for non-small cell lung cancer (NSCLC). We aimed to identify sex differences on perioperative outcomes in NSCLC patients and to uncover the origins of sex effect in outcomes using a Chinese cohort. We retrospectively enrolled patients undergoing NSCLC surgery in the Western China Lung Cancer Database from January 2014 to April 2021. We compared baseline characteristics and perioperative outcomes between male and female. Multivariable analyses were performed. We conducted causal mediation analysis to identify drivers to sex differences in perioperative outcomes. Altogether, data of 10,181 patients (5,738 women and 4,443 men) were analyzed. Women had lower incidence of complications (5.05% vs. 12.15%), shorter postoperative length of stays (4.92 vs. 6.41 days), and less hospitalization cost (50,713.69 vs. 54,580.85, Chinese Yuan). Multivariable regression analysis identified sex as an independent factor of perioperative complications [odds ratio (OR), 1.843, 95% confidence interval (CI): 1.476-2.294], as well as of postoperative length of hospital stays (beta 0.123, 95% CI: 0.099-0.148), and hospitalization cost (beta 0.026, 95% CI: 0.026-0.026). Mediation analysis revealed that age, body mass index, prevalence of chronic obstructive pulmonary disease, predicted diffusion capacity for carbon monoxide, tumor size, pleural adhesion, and surgery duration were identified as mediators for sex differences in outcomes, while smoking status, surgery type, and resection extent were not. Female NSCLC patients demonstrated lower incidence of complications, shorter postoperative length of stays, and less hospitalization cost after surgery. Those differences between men and women could be explained by their inherent biological differences and baseline health status. Perioperative management strategies for NSCLC should prioritize recognizing the potentially poorer outcomes among male patients and implementing tailored precautions accordingly.

Sex-Dependent Changes in Gonadotropin-Releasing Hormone Neuron Voltage-Gated Potassium Currents in a Mouse Model of Temporal Lobe Epilepsy.

Temporal lobe epilepsy (TLE) is the most common focal epilepsy in adults, and people with TLE exhibit higher rates of reproductive endocrine dysfunction. Hypothalamic gonadotropin-releasing hormone (GnRH) neurons regulate reproductive function in mammals by regulating gonadotropin secretion from the anterior pituitary. Previous research demonstrated GnRH neuron hyperexcitability in both sexes in the intrahippocampal kainic acid (IHKA) mouse model of TLE. Fast-inactivating A-type (I A) and delayed rectifier K-type (I K) K+ currents play critical roles in modulating neuronal excitability, including in GnRH neurons. Here, we tested the hypothesis that GnRH neuron hyperexcitability is associated with reduced I A and I K conductances. At 2 months after IHKA or control saline injection, when IHKA mice exhibit chronic epilepsy, we recorded GnRH neuron excitability, I A, and I K using whole-cell patch-clamp electrophysiology. GnRH neurons from both IHKA male and diestrus female GnRH-GFP mice exhibited hyperexcitability compared with controls. In IHKA males, although maximum I A current density was increased, I K recovery from inactivation was significantly slower, consistent with a hyperexcitability phenotype. In IHKA females, however, both I A and I K were unchanged. Sex differences were not observed in I A or I K properties in controls, but IHKA mice exhibited sex effects in I A properties. These results indicate that although the emergent phenotype of increased GnRH neuron excitability is similar in IHKA males and diestrus females, the underlying mechanisms are distinct. This study thus highlights sex-specific changes in voltage-gated K+ currents in GnRH neurons in a mouse model of TLE and suggesting potential sex differences in GnRH neuron ion channel properties.

Preslaughter feed withdrawal and sex influences on rabbit physiological response and meat quality

Although preslaughter feed withdrawal is commonly used in the livestock industry to reduce the risk of viscera puncture during evisceration, the optimal feed withdrawal time (FWT) appears to be species dependent and is not yet well defined in rabbits. This study aimed to evaluate the impact of three preslaughter FWTs while considering the effect of sex on physiological response and meat quality of rabbits. Three FWTs (4, 11 and 18 h) were tested using 144 recently weaned Grimaud rabbits fed until they reached an average commercial slaughter live body weight of 2.5±0.2 kg. Rabbits were allocated into 24 cages, with six animals in each cage. Eight cages (four cages for females and four cages for males) were assigned to each of the three FWTs. Blood lactate concentrations measured at exsanguination did not raise concerns related to stress. Female rabbits subjected to 4 h FWT had a higher gastrointestinal tract weight compared to male rabbits and to other females subjected to 11 and 18 h FWT (P=0.04). Stomach content weights were lower after 18 h FWT compared to 4 and 11 h (P=0.002) for both sexes, while caecum weights were not affected by FWT. Caecum pH was higher after 11 and 18 h FWT compared to 4 h (P=0.02). Technological meat quality was not particularly affected by FWT, except for Longissimus lumborum drip loss which was lower for rabbits after 18 h FWT compared to 4 h FWT (P=0.005). With respect to microbiological meat quality, the end of shelf life was reached after 10 days for vacuum-packed hind legs from rabbits after 11 h FWT, as Escherichia coli cell counts for four out of the eight hind legs analysed were higher than 3 Log10 colony-forming units (CFU)/10 g. For the other two FWT groups, the end of shelf life was reached after 15 d, at which point the cell counts for all hind legs were ≥3 Log10 CFU/10 g for E. coli and ≥7 Log10 CFU/g for total aerobic mesophilic and presumptive lactic acid bacteria (the maximum threshold concentrations according to current regulations). Our results demonstrate that when transport (30 min) and lairage (30 min) times are short (1 h in total), an 18-h preslaughter feed withdrawal for both male and female rabbits can allow the gut to empty properly with limited effect on meat quality.