Estrogenic signaling shapes and modifies daily and circadian rhythms, the disruption of which has been implicated in psychiatric, neurologic, cardiovascular, and metabolic disease, among others. However, the activational mechanisms contributing to these effects remain poorly characterized. To determine the activational impact of estrogen on daily behavior patterns and differentiate between the contributions of the estrogen receptors ESR1 and ESR2, ovariectomized adult female mice were administered estradiol, the ESR1 agonist propylpyrazole triol, the ESR2 agonist diarylpropionitrile, or cholesterol (control). Animals were singly housed with running wheels in a 12-hour light, 12-hour dark cycle or total darkness. Estradiol increased total activity and amplitude, consolidated activity to the dark phase, delayed the time of peak activity (acrophase of wheel running), advanced the time of activity onset, and shortened the free running period (τ), but did not alter the duration of activity (α). Importantly, activation of ESR1 or ESR2 differentially impacted daily and circadian rhythms. ESR1 stimulation increased total wheel running and amplitude and reduced the proportion of activity in the light vs the dark. Conversely, ESR2 activation modified the distribution of activity across the day, delayed acrophase of wheel running, and advanced the time of activity onset. Interestingly, τ was shortened by estradiol or either estrogen receptor agonist. Finally, estradiol-treated animals administered a light pulse in the early subjective night, but no other time, had an attenuated response compared with controls. This decreased phase response was mirrored by animals treated with diarylpropionitrile, but not propylpyrazole triol. To conclude, estradiol has strong activational effects on the temporal patterning and expression of daily and circadian behavior, and these effects are due to distinct mechanisms elicited by ESR1 and ESR2 activation.

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Spinal cord injuries (SCI) pose an immense challenge from a clinical perspective as current treatments and interventions have been found to provide marginal improvements in clinical outcome (with varying degrees of success) particularly in areas of motor and autonomic function.In this review, the pathogenesis of SCI will be described, particularly as it relates to the necroptotic pathway which has been implicated in limiting recovery of SCI via its roles in neuronal cell death, glial scarring, inflammation, and axonal demyelination and degeneration.Major mediators of the necroptotic pathway including RIPK1, RIPK3, and MLKL will be described in detail regarding their role in facilitating necroptosis. Additionally, due to the rapid accumulation of reactive oxygen species (ROS) and inflammatory markers, the onset of necroptosis can begin within hours following SCI, thus developing therapeutics that readily cross the blood-brain barrier (BBB) and inhibit necroptosis during these critical periods of inflammation are imperative in preventing irreversible damage. As such, current therapeutic interventions regarding SCI and targeting of the necroptotic pathway will be explored as will discussion of potential future therapeutics that show promise in minimizing long-term or permanent damage to the spinal cord following severe injury.

Pregnancy-related pain in the sacroiliac joint (SIJ), lumbosacral region, pubic symphysis, or in any combination of these joints has been coined as pelvic girdle pain (PGP) and has been estimated to affect almost half of all pregnant women. SIJ dysfunction in pregnancy is due to multiple biomechanical mechanisms, such as increased weight, change in posture, increased abdominal and intrauterine pressure, and laxity of the spine and pelvic structures. Moreover, when compared to men, women have increased SIJ mobility due to increased pubic angle and decreased SIJ curvature. These differences may assist in parturition where hormones, such as relaxin and estrogen, cause symphysiolysis. A retrospective review of the literature was conducted in the PubMed database using the search term "pregnancy-related sacroiliac joint pain." All peer-reviewed studies were included. Around 8%-10% of women with PGP continue to have pain for one to two years postpartum. Patients that were treated with SIJ fusion show statistically significant improvement in pain scores when compared to patients that had non-operative treatment. Although we have a number of studies following patients after sacroiliac (SI) joint fusion for pelvic pain with SI joint dysfunction, further research is needed to study sacroiliac fusion for SI joint dysfunction in postpartum women to better tailor and optimize surgical outcomes for this patient population.

Background: Although comprising 7% of all spinal tumors, sacral tumors present with a litany of issues due to their slow growth and difficulty in detection. As a result, sacral tumors can grow unperturbed for years until a patient presents for an incidental workup of an unassociated minor trauma or an offending primary tumor source that has metastasized to the sacrum; in most cases, this includes primary tumors of the breast, prostate, and lung. The goal of this review is to outline the pathophysiology underlying sacral tumors including the various tissues and structures that can be targeted for treatment, along with a discussion of the surgical approach to sacrectomy. Methods: An extensive review of the published literature was conducted through PubMed database with articles simultaneously containing both search terms “sacral tumors” and “sacrectomy.” No date restrictions were used. Results: The search yielded 245 related articles. Cross-checking of articles was conducted to exclude of duplicate articles. The articles were screened for their full text and English language availability. We finalized those articles pertaining to the topic. Conclusion: Once a sacral tumor has reached the point of diagnostic detection, invasive sacrectomy is typically utilized (through an anterior, posterior, or combination approach) to locally isolate and resect the tumor and minimize risk of future tumor growth and additional bone loss. While institutions have varying criteria for surgical approaches, a combination of anterior and posterior approach has traditionally been used in total and high sacrectomies due to the control it provides surgeons toward the rectum and vasculature anterior to the sacrum. A posterior-only approach can be performed for tumors that failed to invade pelvic organs or extend past the lumbosacral junction. Early detection with screenings can help avoid invasive sacrectomy by identifying the onset of tumor formation in the sacrum, particularly for highly metastatic cancers.