Intact Females Research Articles

G-protein–coupled estrogen receptor 30 regulation of signaling downstream of protein kinase Cε mediates sex dimorphism in hyaluronan-induced antihyperalgesia

Abstract High molecular weight hyaluronan (HMWH) inhibits hyperalgesia induced by diverse pronociceptive inflammatory mediators and their second messengers, in rats of both sexes. However, the hyperalgesia induced by ligands at 3 pattern recognition receptors, lipopolysaccharide (a toll-like receptor 4 agonist), lipoteichoic acid (a toll-like receptor 2/6 agonist), and nigericin (a NOD-like receptor family, pyrin domain containing 3 activator), and oxaliplatin and paclitaxel chemotherapy–induced peripheral neuropathy are only attenuated in males. After gonadectomy or intrathecal administration of an antisense to G-protein–coupled estrogen receptor 30 (GPER) mRNA, HMWH produces antihyperalgesia in females. In nociceptors cultured from rats that had been treated with oxaliplatin, HMWH reverses nociceptor sensitization from male and GPER antisense–treated female, but not from gonad intact females. G-protein–coupled estrogen receptor–dependent sex dimorphism for HMWH-induced antihyperalgesia was also observed for the prolongation of prostaglandin E2 (PGE2)-induced hyperalgesia in primed nociceptors. While in primed rats, HMWH inhibits early, protein kinase A-dependent hyperalgesia, 30 minutes post PGE2 injection, in both sexes; measured 4 hours post-PGE2, HMWH inhibits the protein kinase Cε (PKCε)-dependent prolongation of PGE2 hyperalgesia only in males and GPER antisense–treated females. In females, hyperalgesia induced by PKCε agonist, ψεRACK, in control but not in primed nociceptors, was inhibited by HMWH. Inhibitors of 2 GPER second messengers, extracellular-regulated kinase 1/2 and nonreceptor tyrosine kinase, also unmasked HMWH antihyperalgesia in females with oxaliplatin chemotherapy–induced peripheral neuropathy, a condition in which nociceptors are primed as well as sensitized. Our results support GPER-dependent sex dimorphism in HMWH-induced antihyperalgesia for pain induced by pattern recognition receptor agonists, and chronic inflammatory and neuropathic pain, mediated by changes in signaling downstream of PKCε in primed nociceptors.

Renewal of conditioned fear in male and female rats.

Pavlovian extinction reduces the performance of conditioned responses and occurs when the conditioned stimulus (CS) is repeatedly presented in the absence of the unconditioned stimulus (US). However, when the CS is experienced in a context that is different from the extinction context, there is a recovery of the conditioned response, a phenomenon known as renewal. There is some evidence that the renewal of appetitive conditioning is influenced by sex, with females failing to exhibit renewed responding. Further, there is recent evidence that renewal of fear might also not occur in female rats. In both appetitive and fear preparations, the lack of renewal in females has been postulated to be related to cycling ovarian hormones. Therefore, in Experiments 1 and 2, we directly compared fear renewal in males and females (Experiment 1) as well as ovariectomized (OVX) females (Experiment 2) when conditioning occurred in Context A, extinction in B, and testing in A (ABA renewal). Experiments 3 and 4 examined renewal when conditioning and extinction occurred in A and testing occurred in B (AAB renewal). In all experiments, renewal was not significantly different between male and female rats. Further, in Experiments 2 and 4, renewal did not differ between males, intact females, and OVX females. Additionally, in each experiment, there was no evidence that context excitation and/or inhibition contributed to renewal; instead suggesting that renewal was controlled by an occasion-setting mechanism. Overall, these results suggest little evidence for the role of sex in renewal of conditioned freezing and also indicate that cycling ovarian hormones have little role in the strength of renewal in female rats. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Abstract P148: Loss of Ovarian Estrogen Downregulates Renal Steroidogenesis

Hypertension impacts half of US adults and importantly is more prevalent in men than premenopausal women. Sex hormones, particularly estrogen, have been implicated in this sex-difference. Recently we showed renal medullary estrogenic signaling via the G protein-coupled estrogen receptor 1 promotes sodium excretion in female, but not male, Sprague Dawley (SD) rats which implicates estrogen as a possible female-specific natriuretic factor. This led us to question whether the kidney could produce its own steroids, including estrogen, to respond to salt load changes locally. Evidence in cultured COS-7 and fetal kidney cells indicates the expression and activity of steroidogenic enzymes. Recently, we showed the outer medulla of the female SD rat kidney expresses key enzymes and metabolites involved in sex steroid biosynthesis. It is unknown how ovarian estrogen regulates steroidogenesis in the kidney. We hypothesize that ovarian estrogen stimulates the intrarenal capacity to biosynthesize sex steroids. To test this, we measured mRNA expression of several steroidogenic enzymes in the renal outer medulla of gonadally-intact female or ovariectomized SD rats (N=6). Cholesterol is the initial substrate for steroid synthesis. Thus, we first measured HMG-CoA reductase (HMGCR), the key synthesizing enzyme for cholesterol and steroidogenic acute regulatory protein (StAR), which helps commit cholesterol to steroid synthesis. Ovariectomy (OVX) reduced mRNA expression of both when compared to intact females (HMGCR: 63.5 ± 6.2 vs 100.0 ± 10.7 P=0.0169; StAR: 66.6 ± 12.4 vs 100.0 ± 6.4 P=0.0298). Although not significantly different, OVX seemed to reduce the expression of hydroxysteroid 3-β Dehydrogenase, which converts several intermediate steps in androgen and estrogen synthesis, compared to intact females (73.4 ± 13.3 vs 100.0 ± 9.7 P=0.1283). Hydroxysteroid 17-β Dehydrogenase (17β-HSD) 1, which converts estrone to estradiol, was unchanged in OVX compared to intact females (107.6 ± 13.2 vs 100.0 ± 10.1 P=0.6537). OVX reduced expression of 17β-HSD2 (28.34 ± 7.8 vs 100.0 ± 12.85 P=0.0008) and 17β-HSD3 (71.1 ± 7.5 vs 100.0 ± 5.7 P=0.0097) which interconvert androstenedione and testosterone compared to intact females. Combined these data suggest that ovariectomy blunts the intrarenal machinery for steroidogenesis. Additional experiments are required to test whether menopause downregulates renal sex steroid biosynthesis and predisposes postmenopausal women to hypertension.

Cholinergic interneurons in the nucleus accumbens are a site of cellular convergence for corticotropin-releasing factor and estrogen regulation in male and female mice.

Cholinergic interneurons (ChIs) act as master regulators of striatal output, finely tuning neurotransmission to control motivated behaviours. ChIs are a cellular target of many peptide and hormonal neuromodulators, including corticotropin-releasing factor, opioids, insulin and leptin, which can influence an animal's behaviour by signalling stress, pleasure, pain and nutritional status. However, little is known about how sex hormones via estrogen receptors influence the function of these other neuromodulators. Here, we performed in situ hybridisation on mouse striatal tissue to characterise the effect of sex and sex hormones on choline acetyltransferase (Chat), estrogen receptor alpha (Esr1) and corticotropin-releasing factor type 1 receptor (Crhr1) expression. Although we did not detect sex differences in ChAT protein levels in the dorsal striatum or nucleus accumbens, we found that female mice have more Chat mRNA-expressing neurons than males in both the dorsal striatum and nucleus accumbens. At the population level, we observed a sexually dimorphic distribution of Esr1- and Crhr1-expressing ChIs in the ventral striatum that was negatively correlated in intact females, which was abolished by ovariectomy and not present in males. Only in the NAc did we find a significant population of ChIs that co-express Crhr1 and Esr1 in females and to a lesser extent in males. At the cellular level, Crhr1 and Esr1 transcript levels were negatively correlated only during the estrus phase in females, indicating that changes in sex hormone levels can modulate the interaction between Crhr1 and Esr1 mRNA levels.

The positive reinforcing effects of cocaine and opposite-sex social contact: roles of biological sex and estrus.

Preclinical studies report that drug use and social contact mutually influence the reinforcing effects of one another. Most of these studies have used same-sex dyads exclusively, and the role of factors related to biological sex and hormonal fluctuations are not well understood. The purpose of this study was to examine the reinforcing effects of cocaine and social contact with an opposite-sex partner in male and female rats, and how these effects are modulated by ovarian hormones. Male and female rats were trained in a nonexclusive choice procedure in which cocaine and social contact with an opposite-sex partner were simultaneously available on concurrent progressive ratio schedules of reinforcement. To examine the effects of ovarian hormones related to estrous cycling, Experiment 1 used naturally cycling, gonadally intact females, whereas Experiment 2 used ovariectomized females, and estrus was artificially induced with exogenous hormones. In both experiments, cocaine and social contact functioned as robust reinforcers, and there were no significant effects of biological sex or estrus status of the females. The positive reinforcing effects of both cocaine and social contact increased as a function of cocaine dose, indicating that contingent cocaine administration increases the reinforcing effects of social contact. These data suggest that cocaine use among opposite-sex partners may enhance factors that contribute to social bonding.

Testosterone and Erythrocyte Lifespan.

Endogenous and exogenous androgens increase circulating erythrocytes and hemoglobin but their effects on erythrocyte lifespan is not known. To investigate androgen effects on immature and mature erythrocyte lifespan in humans and mice using novel non-radioactive minimally invasive methods. Human erythrocyte lifespan was estimated using alveolar carbon monoxide concentration and blood hemoglobin in Levitt's formula in hypogonadal or transgender men before and up to 18 weeks after commencing testosterone (T) treatment. Erythrocyte lifespan was estimated in androgen receptor (AR) knockout and wild-type mice after T or dihydrotestosterone (DHT) treatment of intact females or orchidectomized males using in vivo biotin labelling of erythrocyte surface epitopes for reticulocytes (Ter119+CD71+) and two markers of erythrocytes (CD45-, Ter119+CD71-) monitoring their blood disappearance rate by flow cytometry. Before treatment, hypogonadal and transgender men had marked reduction in erythrocyte lifespan compared with controls. T treatment increased erythrocyte lifespan at 6 weeks but returned to pre-treatment levels at 18 weeks while serum T and blood hemoglobin were increased by T treatment remaining elevated at 18-weeks. In mice T and DHT treatment had higher erythrocyte (but not reticulocyte) lifespan but neither orchidectomy nor AR inactivation significantly influenced erythrocyte or reticulocyte lifespan. We conclude that hypogonadal men have reduced erythrocyte lifespan and acute androgen-induced increase in circulating erythrocyte lifespan may contribute to the well-known erythropoietic effects of androgens, but longer-term effects require further investigation to determine how much they contribute to androgen-induced increases in circulating hemoglobin.

High circulating concentrations of estradiol are anabolic for bone mass and strength in an adult male to female transgender mouse model

The effects of gender affirming hormone therapy (GAHT) on bone microarchitecture and fracture risk in adult transgender women is unclear. To investigate the concept that skeletal integrity and strength in trans women may be improved by treatment with a higher dose of GAHT than commonly prescribed, we treated adult male mice with a sustained, high dose of estradiol. Adult male mice at 16 weeks of age were administered ~1.3 mg estradiol by silastic implant, implanted intraperitoneally, for 12 weeks. Controls included vehicle treated intact females and males. High-dose estradiol treatment in males stimulated the endocortical deposition of bone at the femoral mid-diaphysis, increasing cortical thickness and bone area. This led to higher stiffness, maximum force, and the work required to fracture the bone compared to male controls, while post-yield displacement was unaffected. Assessment of the material properties of the bone showed an increase in both elastic modulus and ultimate stress in the estradiol treated males. Treatment of male mice with high dose estradiol was also anabolic for trabecular bone, markedly increasing trabecular bone volume, number and thickness in the distal metaphysis which was accompanied by an increase in the histomorphometric markers of bone remodelling, mineralizing surface/bone surface, bone formation rate and osteoclast number. In conclusion, a high dose of estradiol is anabolic for cortical and trabecular bone in a male to female transgender mouse model, increasing both stiffness and strength. These findings suggest that increasing the current dose of GAHT administered to trans women, while considering other potential adverse effects, may be beneficial to preserving their bone microstructure and strength.

Ovariectomy Increases Blood Pressure and FosB Staining in the Central Autonomic Control Regions Independent of Chronic Intermittent Hypoxia

Chronic intermittent hypoxia (CIH) experimentally mimics the recurrent hypoxia characteristic of sleep apnea, and it induces sustained hypertension in male and ovariectomized (OVX) female rats but not intact females. While central autonomic control regions are known to mediate CIH-induced hypertension in males, their contribution to CIH hypertension in OVX females remains unclear. We tested the hypothesis that 7 days of CIH increases mean arterial pressure (MAP) and FosB staining in central autonomic regions in OVX but not intact female rats. Adult female Sprague Dawley gonadally intact (INT) or OVX rats were exposed to 7 days of CIH (10% O2 and 21% O2 cycle, every 6 mins, 8h/day) or continuous normoxia (CON). MAP was monitored by radiotelemetry. On day 8, the rats were sacrificed, and their brains were collected and processed for FosB immunohistochemistry. During the light/sleep phase, CIH increased MAP in INT females (n=7; 3.4 ± 0.4 mmHg) as compared to CON (n=6, ΔMAP 1.4 ± 0.3 mmHg; P=0.01 CON vs CIH). This difference was not observed during the dark/active phase (CON ΔMAP -1.7 ± 0.4 mmHg, CIH 0.5 ± 0.3 mmHg, P=0.07). In OVX females, CIH was not associated with significant increases in MAP during the light/sleep phase (CON (n=6) ΔMAP 0.3 ± 0.4 mmHg, CIH (n = 6) 2.1 ± 0.3 mmHg, P=0.10). During the dark phase, MAP was significantly increased in CON OVX and CIH OVX compared to their respective baselines but there were no differences between groups (CON ΔMAP 2.4 ± 0.3 mmHg, CIH 2.2 ± 0.4 mmHg, P=0.0002 vs baseline, P=0.8 CON vs CIH). OVX rats had higher baseline FosB staining in the median preoptic nucleus compared to intact female rats independent of CIH exposure (INT: CON (n = 6) 13 ± 3 cells/section, CIH (n = 6) 14 ± 2; OVX: CON (n = 6) 21 ± 3, CIH (n = 6) 23 ± 2, INT CON vs OVX CON, P < 0.05, INT CIH vs OVX CIH P < 0.05). Compared to CON, CIH significantly increased the number of FosB immunoreactive cells in the caudal nucleus of the solitary tract in INT but not OVX females (INT: CON, 7 ± 1 cells/section, CIH 11 ± 1; OVX CON 6 ± 1, CIH n=6, 9 ± 1; INT CON vs CIH, P=0.02; OVX CON vs CIH, P = 0.09). In the rostral ventrolateral medulla, there were no significant differences among any of the groups (INT: CON n=4, 19 ± 2 cells/section, CIH n=4, 20 ± 3; OVX: CON n=6, 18 ± 2, CIH n=6, 21 ± 2, all P>0.05). In OVX females, CIH tended to increase MAP during both the light and dark phases. CON OVX females showed a trend for increased MAP during the dark phase, independent of CIH. CIH was not associated with increased FosB staining in either the median preoptic nucleus or the rostral ventrolateral medulla of OVX females This suggests that changes in MAP observed in CIH OVX females may not involve the same autonomic control regions as male rats exposed to CIH. Supported by RO1 HL155977. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Mind the Gap: Estrogen Receptor-β in Astrocytes Is a Therapeutic Target to Prevent Cognitive Problems at Menopause [ID 2683385

INTRODUCTION: Menopause entails cognitive deficits and brain atrophy, but the brain region and cell-specific mechanisms remain unclear. METHODS: Aging female mice were examined for cognitive deficits, hippocampal atrophy by MRI, and neuropathology. RESULTS: A sex hormone by age interaction was discovered. Loss of ovarian hormones in female mice at midlife, but not young age, induced hippocampal-dependent cognitive impairment, dorsal hippocampal atrophy, and glial activation with synaptic loss. Deletion of estrogen receptor-β (ERβ) in astrocytes, but not neurons, in gonadally intact females recapitulated these effects. RNA sequencing and pathway analyses of gene expression in hippocampal astrocytes from midlife female astrocyte-ERβ conditional knockout (cKO) mice revealed Gluconeogenesis I and Glycolysis I as the most differentially expressed pathways. Enolase 1 gene expression was increased in hippocampi from astrocyte-ERβ cKO at midlife and postmenopausal women. ERβ ligand treatment at midlife reversed dorsal hippocampal neuropathology. CONCLUSION: Estrogen receptor-β in hippocampal astrocytes modulates cognitive function in mid-age female mice.

Investigation of neutering status and age of neutering in female Dachshunds with thoracolumbar intervertebral disc extrusion.

To evaluate neutering status and age of neutering in female Dachshunds with thoracolumbar intervertebral disc extrusion. We hypothesised that neutered Dachshunds presented with intervertebral disc extrusion at an earlier age, with a higher grade of neurological deficits and with more extensive extrusion of disc material compared with intact females. Retrospective multi-centre study of client-owned female Dachshunds with surgically confirmed thoracolumbar intervertebral disc extrusion. Dogs were classified as early, late or not neutered (intact). Age, body condition score, duration of clinical signs before presentation, modified Frankel score at presentation, length of extruded disc material, maximum spinal cord compression and whether dogs presented for a subsequent intervertebral disc extrusion were recorded. One hundred and fifty-four dogs were included: 36 early neutered, 69 late neutered and 49 intact. No significant difference was found between early neutered, late neutered and entire female Dachshunds in any of the variables studied. In this cohort of female dogs, neuter status and age of neutering were not found to affect age at onset nor severity of thoracolumbar intervertebral disc extrusion.

Anatomical and topographic substantiation of various accesses to the proximal epiphysis of the tibia

One of the most frequently performed accesses in the practice of an orthopedic veterinarian is access to the proximal epiphysis of the tibia. Access to the proximal epiphysis of the tibia is necessary in many cases of treatment of pathologies of the musculoskeletal system in cats and dogs and can be used in such surgical pathologies. The aim of the study was to consider options for surgical access to the proximal epiphysis of the tibia to perform osteosynthesis of fractures according to the Salter–Harris type, and osteotomy leveling the slope of the tibial plateau (TPLO) with anatomical and topographic justification. The study was conducted in the Network of veterinary centers "Kotonai" and the Department of Animal Anatomy of the St. Petersburg State University of Veterinary Medicine. The object of the study was dogs of small and medium breeds in the number of twelve individuals. The average age of the patients ranged from 6 months to 12 years. The study involved 5 intact females and 7 intact males. The average weight at the time of the study ranged from 2.5 to 21.0 kg. In the process of collecting the life history of all patients, the presence of chronic diseases, allergies and infectious diseases is excluded. The initial examination of the animal included: collection of anamneses of life and illness, general clinical examination, thermometry, neuroorthopedic examination, auscultation of the heart and lungs, X-ray examination under sedation. General clinical examination, thermometry and auscultation of the heart and lungs did not reveal pathological changes in all cases. According to the results of the study, it was found that there were no severe postoperative complications requiring repeated treatment in the studied patients. With the observance of clear anatomical and topographic landmarks in the formation of accesses, a good understanding of the anatomy of the medial and cranial surfaces of the tibia, visualization in the wound during surgical interventions (osteosynthesis of SalterHarris fractures, TPLO osteotomy) in the area of the proximal epiphysis of the tibia is convenient and safe.

DOPAMINE AND NOREPINEPHRINE CONTENT IN THE CEREBRAL CORTEX OF BALB/C NUDE MICE WITH MULTIPLE PRIMARY MALIGNANT TUMOURS

The increase in patients with multiple primary malignant tumors (MPMT) determines the need to study their pathogenesis. An important role in the functioning of brain neurons belongs to norepinephrine (NA) and dopamine (DA), which can contribute to tumor development in immunodeficient mice of both sexes.
 The purpose of our work was a comparative analysis of dopamine and norepinephrine content in the cerebral cortex of immunodeficient mice of both sexes during isolated and combined growth (MPMT model) of experimental tumors.
 Materials and Methods. 56 BALB/c Nude mice were divided into 7 groups: 4 groups of females (intact, mice with standard subcutaneous inoculation of B16/F10 melanoma or Lewis lung carcinoma (LLC), mice with MPMT model – subcutaneous injection of a tumor cell suspension); 3 groups of males (the same groups as for females, except LLC). ELISA technique was used to detect NA and DA content.
 Results. In the cerebral cortex of intact females, DA level was higher (3.7 times) and NA level was lower (1.8 times) when compared to males. In all types of tumor growth, monoamine level decrease was observed in animals of both sexes. In females, DA decrease was 57.2 % and 65.8 % with isolated B16/F10 melanoma growth and LLC, and with MPMT it reached 70 %. In males, DA decreased significantly only with MPMT – by 37.6 %. NA in females decreased in case of LLC and MPMT by 26.2 % and 28.1 %, respectively. In males, NA decreased with B16/F10 melanoma and MPMT by 53.3 % and 43 % respectively (p<0.0001 in all cases). In females, there was a more than twofold increase in the ratio of stress-implementing NA and stress-limiting DA (NA/DA) levels, while in males there was a decrease in this index. This was consistent with the large tumor sizes (2–3 times larger) in case of MPMT in females.
 Conclusion. The results indicate the participation of brain neurotransmitters in the development of multiple primary malignant tumors in BALB/c Nude mice of both sexes and lower stress resistance in females.

Causes of Sex Differences in Serum Cholesterol and Triglyceride Levels in Meishan Pigs.

To clarify the causes of sex differences (male < female) in the serum total cholesterol (TCHO) and triglyceride (TG) levels in Meishan pigs, we examined the sex differences in mRNA levels of key hepatic enzymes involved in the biosynthesis/metabolism of cholesterol and TG using real-time RT-PCR. There were no sex differences in mRNA levels of 3-hydroxy-3-methylglutaryl-CoA reductase and CYP51A1 for cholesterol biosynthesis, or of the rate-limiting enzyme CYP7A1 for bile acid synthesis from cholesterol. By contrast, sex differences (male < female) were observed in mRNA levels of glycerol-3-phosphate acyltransferase 1 (GPAT1), a rate-limiting enzyme for TG biosynthesis. However, the sex differences in mRNA levels of carnitine palmitoyltransferase 1A (CPT1A) and acyl-CoA dehydrogenase long chain (ACADL), key enzymes for the oxidation of the fatty acids that are structural components of TG, were the opposite (male > female). Castration of male pigs led to an increase in the mRNA level of GPAT1 and decreases in those of CPT1A and ACADL. Furthermore, testosterone propionate (TP)-treatment of castrated males and intact females restored and changed, respectively, these mRNA levels to those of intact males. Notably, castration and TP-treatment increased and decreased, respectively, serum and hepatic TG levels. These findings suggest that sex differences in the serum and hepatic TG levels in Meishan pigs are closely correlated with differences in testosterone-associated mRNA expression levels of the key enzymes (GPAT1, CPT1A, and ACADL) involved in the TG biosynthesis process, although no causes of sex differences in serum and hepatic TCHO levels could be found.

Risk factor analysis and clinicopathological characteristics of female dogs with mammary tumours from a single-center retrospective study in Poland

This is a comprehensive retrospective study to characterize female dogs with canine mammary tumors (CMTs) using a dataset retrieved from the archives of the Division of Animal Pathology, Institute of Veterinary Medicine in Warsaw, and to identify prognostic factors. Clinical and histopathological data of 1447 dogs with CMTs were included. Malignant tumours were found in 83.3% (n = 1206), benign tumours in 11.7% (n = 169), and non-neoplastic lesions in 5.0% (n = 72) of dogs. Dogs most often had grade II carcinomas (38.2%, 215/562) of a single histological subtype (88.5%, 1281/1447), mostly simple carcinoma (35.3%, 510/1447). Dogs with a median age of 10 years significantly often had larger (≥ 3 cm) and malignant CMTs, whereas intact females had smaller tumours (median size 2.0 cm). However, the threshold value for the age of the dog in the differentiation of malignant and non-neoplastic/benign masses could not be determined. Most females were hormonally active (76.4%, 372/487). Hormonally active dogs significantly more often had multiple tumours. Multiple tumours were significantly smaller (median 2.5 cm) than single ones. Among pedigree dogs, small-breed dogs were mostly recorded (43%, 428/1006). Twelve breeds had an increased risk of CMTs, regardless of tumour behaviour, compared with the theoretical distribution of pedigree dogs in Poland. Four breeds were often affected only by malignant and other four breeds only by non-neoplastic/benign CMT. Large-breed dogs were significantly younger and affected by larger CMT (median 4 cm) compared with small- and medium-breed dogs. Ninety dogs with a malignant CMT and complete records were included in the full analysis of CMT-specific survival (CMT-SS) with a median follow-up time of 20.0 months. We showed that the timing of ovariohysterectomy in relation to mastectomy was significantly associated with grade, CMT-SS, and CMT-related death. We indicated the low diagnostic accuracy of palpation of regional lymph nodes (RLN) in the prediction of their metastatic involvement. By multivariable analysis, dogs with neoplastic emboli, tumour ulceration, and simple or complex carcinoma had a significantly higher risk of local recurrence. Tumour size > 3 cm was as a strong independent predictor of lung metastases. Compared with dogs with an easily separated localized tumour, dogs with a multiple/diffuse malignant CMT pattern had a fivefold higher risk of death. The risk of death was significantly higher in the presence of neoplastic emboli (~ fivefold) and tumour ulceration (~ fourfold). Furthermore, the presence of neoplastic emboli and large tumour size were independent predictors of CMT-related death.

An In-Depth Look at Fonni's Dog Behavior under Different Outdoor Conditions.

This study aimed to investigate the common social and communicative behaviors of the Fonni's Dog under different outdoor conditions. For this study, 70 adult dogs (3-7 years; 32 intact males, 38 intact females) belonging to the Fonni's breed were used. A total of 35 dogs were kept in kennels and 35 were free-ranging dogs in their sheep/goat livestock units. A behavioral repertoire was adapted from the literature and an ethogram was filled in for each dog. All dogs were evaluated in the presence of the owner. Fisher's exact test, following Bonferroni's correction, was used to test possible differences in the categorical variables (presence or absence of the behavior) between free-ranging dogs and dogs kept in kennels. The study revealed that several categories of the dogs' body language were associated with the management condition. However, the breed motivations (guarding and defense of the territory) were satisfied both in kennel and in the animals who were free in the property. The current study suggests a good behavioral balance of the Fonni's Dogs which could be attributed to correct communication between dogs and owners.

Estradiol increases cortical and trabecular bone accrual and bone strength in an adolescent male-to-female mouse model of gender-affirming hormone therapy

The effects of gender-affirming hormone therapy on the skeletal integrity and fracture risk in transitioning adolescent trans girls are unknown. To address this knowledge gap, we developed a mouse model to simulate male-to-female transition in human adolescents in whom puberty is first arrested by using gonadotrophin-releasing hormone analogs with subsequent estradiol treatment. Puberty was suppressed by orchidectomy in male mice at 5 weeks of age. At 3 weeks post-surgery, male-to-female mice were treated with a high dose of estradiol (~0.85 mg) by intraperitoneal silastic implantation for 12 weeks. Controls included intact and orchidectomized males at 3 weeks post-surgery, vehicle-treated intact males, intact females and orchidectomized males at 12 weeks post-treatment. Compared to male controls, orchidectomized males exhibited decreased peak bone mass accrual and a decreased maximal force the bone could withstand prior to fracture. Estradiol treatment in orchidectomized male-to-female mice compared to mice in all control groups was associated with an increased cortical thickness in the mid-diaphysis, while the periosteal circumference increased to a level that was intermediate between intact male and female controls, resulting in increased maximal force and stiffness. In trabecular bone, estradiol treatment increased newly formed trabeculae arising from the growth plate as well as mineralizing surface/bone surface and bone formation rate, consistent with the anabolic action of estradiol on osteoblast proliferation. These data support the concept that skeletal integrity can be preserved and that long-term fractures may be prevented in trans girls treated with GnRHa and a sufficiently high dose of GAHT. Further study is needed to identify an optimal dose of estradiol that protects the bone without adverse side effects.

On the basis of sex and sleep: the influence of the estrous cycle and sex on sleep-wake behavior.

The recurrent hormonal fluctuations within reproductive cycles impact sleep-wake behavior in women and in rats and mice used in preclinical models of sleep research. Strides have been made in sleep-related clinical trials to include equal numbers of women; however, the inclusion of female rodents in neuroscience and sleep research is lacking. Female animals are commonly omitted from studies over concerns of the effect of estrus cycle hormones on measured outcomes. This review highlights the estrous cycle's broad effects on sleep-wake behavior: from changes in sleep macroarchitecture to regionally specific alterations in neural oscillations. These changes are largely driven by cycle-dependent ovarian hormonal fluctuations occurring during proestrus and estrus that modulate neural circuits regulating sleep-wake behavior. Removal of estrous cycle influence by ovariectomy ablates characteristic sleep changes. Further, sex differences in sleep are present between gonadally intact females and males. Removal of reproductive hormones via gonadectomy in both sexes mitigates some, but not all sex differences. We examine the extent to which reproductive hormones and sex chromosomes contribute to sex differences in sleep-wake behavior. Finally, this review addresses the limitations in our understanding of the estrous cycle's impact on sleep-wake behavior, gaps in female sleep research that are well studied in males, and the implications that ignoring the estrous cycle has on studies of sleep-related processes.

Relationship between the severity of neurological signs in dogs with thoracolumbar intervertebral disc disease and the magnitude of spinal cord compression by disc extrusion as assessed by computed tomography

The aim of this study was to verify the relationship between the degree of severity of neurological signs in dogs with thoracolumbar intervertebral disc disease (TL-IVDD) and the magnitude of spinal cord compression on the computed tomography (CT) transverse view of the vertebra at the site of the greatest narrowing of the spinal canal caused by extruded disc material. In a total of 78 dogs with TL-IVDD, the greatest narrowing of the spinal canal at the site of greatest spinal cord compression was observed in the T11-T12 region (48.35 ± 20.70%) and the smallest in the L2-L3 region (33.06 ± 15.40%). There was a significant difference in the percentage of spinal canal narrowing between the L2-L3 region and the T11-T12 (P = 0.034), T12-T13 (P = 0.033) and T13-L1 (P = 0.022) regions, respectively. Females showed a significantly higher percentage of spinal canal narrowing compared to males (P = 0.029); the highest percentage of spinal canal narrowing was found in neutered females compared to intact females (P = 0.013), neutered males (P = 0.029), and intact males (P = 0.001), respectively. In addition, the dogs included in the study were divided into a group of chondrodystrophic (n = 55) and a group of nonchondrodystrophic (n = 23) dogs. Dogs of chondrodystrophic breeds generally showed a highly significantly (P = 0.001) more severe degree of neurological signs compared to dogs of nonchondrodystrophic breeds. Results of this study can be useful in veterinary practice diagnostics.

Age of Dental Apical Closure in Domestic Cats.

Data on the age of apical closure in felines is limited. Moreover, differences in age of apical closure between male and female cats have not been studied. The aim of this study was to determine the timing of apical closure in cats and determine if sex or position in the dental arch affected closure. In this retrospective descriptive study, intraoral radiographs were obtained at monthly or multiple-monthly intervals for 18 cats. Nine were intact females and 9 were neutered males, ranging from 6 to 9.4 months of age at the start of the study which ranged over an 8-month period. Radiographs were evaluated to establish age of apical closure for all canine teeth as well as the mandibular premolar and molar teeth. Mandibular canine tooth apices closed between 10 and 12 months of age and maxillary canine tooth apices closed between 12 and 14 months of age. The mesial and distal root apices of both the mandibular third and fourth premolar teeth closed between 8 and 9 months. The mandibular first molar tooth mesial and distal root apices closed between 8 and 8.5 months. Root apices of canine teeth closed earlier in female cats than in male cats with mandibular canine tooth root apices closing significantly earlier than maxillary canine tooth roots in both sexes. These findings suggest that there are notable differences in age of apical closure between male and female cats and discernible trends in timing of apical closure among teeth in the dental arcade.

Sex-Specific Acute Cerebrovascular Responses to Photothrombotic Stroke in Mice.

Mechanisms underlying cerebrovascular stroke outcomes are poorly understood, and the effects of biological sex on cerebrovascular regulation post-stroke have yet to be fully comprehended. Here, we explore the overlapping roles of gonadal sex hormones and rho-kinase (ROCK), two important modulators of cerebrovascular tone, on the acute cerebrovascular response to photothrombotic (PT) focal ischemia in mice. Male mice were gonadectomized and female mice were ovariectomized to remove gonadal hormones, whereas control ("intact") animals received a sham surgery prior to stroke induction. Intact wild-type (WT) males showed a delayed drop in cerebral blood flow (CBF) compared with intact WT females, whereby maximal CBF drop was observed 48 h following stroke. Gonadectomy in males did not alter this response. However, ovariectomy in WT females produced a "male-like" phenotype. Intact Rock2+/- males also showed the same phenotypic response, which was not altered by gonadectomy. Alternatively, intact Rock2+/- females showed a significant difference in CBF values compared with intact WT females, displaying higher CBF values immediately post-stroke and showing a maximal CBF drop 48 h post-stroke. This pattern was not altered by ovariectomy. Altogether, these data illustrate sex differences in acute CBF responses to PT stroke, which seem to involve gonadal female sex hormones and ROCK2. Overall, this study provides a framework for exploring sex differences in acute CBF responses to focal ischemic stroke in mice.