Assessment of the effects of sex, age, and rearing condition on ultrasonic vocalizations elicited by pups during the maternal potentiation paradigm in C57BL/6J mice.

Isolation-induced ultrasonic vocalizations (USVs) are important to elicit parental retrieval. This behavior is critical for the animal's survival and can be altered in models of developmental disorders. The potentiation of vocalizations in response to reunion with the dam, also called maternal potentiation, has been extensively studied in rats. However, the assessment of this paradigm in mice is scarce. In rats, the potentiation of vocalizations is dependent on rearing conditions. Since mice are the main species used for genetic models of diseases, we aimed to investigate how different factors such as age, sex, and rearing conditions can affect the potentiation of vocalizations in the maternal potentiation paradigm in mice. We carried out experiments using biparental (dam and sire) or uniparental rearing (dam). Pups were tested on postnatal days (PD) 9 or 12. Pups showed increased potentiation in both sexes at PD9 with uniparental rearing. Both rearing conditions and ages changed the repertoire from the first to the second isolation. Spectral parameters were affected by sex, rearing condition and reunion at PD9. At PD12, only duration was altered by reunion. We conclude that the performance of the pups in the maternal potentiation paradigm is dependent on age, sex, and rearing condition.

NS-Pten knockout mice exhibit sex and hippocampal subregion-specific increases in microglia/macrophage density.

Seizures induce hippocampal subregion dependent enhancements in microglia/macrophage phagocytosis and cytokine release that may contribute to the development of epilepsy. As a model of hyperactive mTOR induced epilepsy, neuronal subset specific phosphatase and tensin homolog (NS-Pten) knockout (KO) mice exhibit hyperactive mTOR signaling in the hippocampus, seizures that progress with age, and enhanced hippocampal microglia/macrophage activation. However, it is unknown where microglia/macrophages are most active within the hippocampus of NS-Pten KO mice. We quantified the density of IBA1 positive microglia/macrophages in the CA1, CA2/3, and dentate gyrus of NS-Pten KO and wildtype (WT) male and female mice at 4, 10, and 15 weeks of age. NS-Pten KO mice exhibited an overall increase in the number of IBA1 positive microglia/macrophages in each subregion and in the entire hippocampus. After accounting for differences in size, the whole hippocampus of NS-Pten KO mice still exhibited an increased density of IBA1 positive microglia/macrophages. Subregion analyses showed that this increase was restricted to the dentate gyrus of both male and female NS-Pten KO mice and to the CA1 of male NS-Pten KO mice. These data suggest enhanced microglia/macrophage activity may occur in the NS-Pten KO mice in a hippocampal subregion and sex-dependent manner. Future work should seek to determine whether these region-specific increases in microgliosis play a role in the progression of epilepsy in this model.

Evaluation of Graft Tensioning Effects in Anterior Cruciate Ligament Reconstruction between Hamstring and Bone-Patellar Tendon Bone Autografts.

This article investigates the clinical, functional, and radiographic outcomes in anterior cruciate ligament (ACL) reconstruction patients over 7 years to determine the effects of initial graft tension on outcomes when using patellar tendon (bone-tendon-bone [BTB]) and hamstring tendon (HS) autografts. Ninety patients, reconstructed with BTB or HS, were randomized using two initial graft tension protocols: (1) normal anteroposterior (AP) laxity ("low-tension"; n = 46) and (2) AP laxity overconstrained by 2 mm ("high-tension"; n = 44). Seventy-two patients had data available at 7 years, with 9 excluded for graft failure. Outcomes included the Knee Injury and Osteoarthritis Outcome Score, Short-Form-36 (SF-36), and Tegner activity scale. Clinical outcomes included KT-1000S and International Knee Documentation Committee examination score; and functional outcomes included 1-leg hop distance and peak knee extensor torque. Imaging outcomes included medial joint space width, Osteoarthritis Research Society International radiographic score, and Whole-Organ Magnetic Resonance Score. There were significantly improved outcomes in the high-tension compared with the low-tension HS group for SF-36 subset scores for bodily pain (p = 0.012), social functioning (p = 0.004), and mental health (p = 0.014) 84 months postsurgery. No significant differences in any outcome were found within the BTB groups. Tegner activity scores were also significantly higher for the high-tension HS group compared with the low-tension (6.0 vs. 3.8, p = 0.016). Patients with HS autografts placed in high tension had better outcomes relative to low tension for Tegner activity score and SF-36 subset scores for bodily pain, social functioning, and mental health. For this reason, we recommend that graft fixation be performed with the knee at 30-degree flexion ("high-tension" condition) when reconstructing the ACL with HS autograft.

Return to Play Following Meniscal Repair.

Meniscal injuries in athletes present a challenging problem. Surgeons must balance the needs of the healing meniscus with the desire of the athlete to return to play as quickly as possible. Evidence-based rehabilitation protocols are important for ensuring a successful meniscal repair and preventing athletes from returning to play prematurely. Ultimately, however, the return to play determination requires a shared decision-making approach between the physician, the athlete, and the providers involved in the athlete's rehabilitation process. This decision considers not only the athlete's ability to meet return-to-play criteria but also their season-specific and career goals.

Relationship of the Musculocutaneous Nerve and Its Twigs to the Coracoid Process: An Operative Exposure.

BACKGROUND: A musculocutaneous nerve (MCN) injury is a rare complication of the Latarjet procedure. Most of these injuries are neurapraxias and resolve with time; however, permanent injuries can occur. Understanding the anatomy and relationship of the MCN to the coracoid process is essential to prevent injuries. PURPOSE: To provide realistic, in situ-referenced measurements for the Latarjet procedure. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 12 matched-pair cadaveric specimens (24 fresh-frozen shoulders) were dissected. Coracoid osteotomy was performed, and the MCN and its respective twigs were identified. Measurements were made from the coracoid process to the entry site of the nerve twigs and trunk into the coracobrachialis muscle. RESULTS: Overall, 70.8% of specimens had twigs; however, there was a discrepancy in the presence (41.7%) and number (75.0%) of twigs in the paired specimens. The most proximal twigs were, on average, 33.5 ± 8.1 mm (range, 21.9-47.6 mm) from the coracoid process. The main trunk was, on average, 51.1 ± 14.4 mm (range, 16.7-71.9 mm) from the coracoid process. In 33.3% of specimens, the nerve entered the coracobrachialis at a distance shorter than 5 cm below the coracoid process, and this increased to 91.7% when the twigs were accounted for. CONCLUSION: The previously described safe zone of 5 cm below the coracoid process may not be reliable to protect the MCN or its twigs. Using 3 cm would decrease the chances of damaging a twig or the main trunk. In 33.3% of the specimens, the nerve entered the coracobrachialis at a distance shorter than 5 cm below the coracoid process, and this increased to 91.7% when twigs were accounted for. CLINICAL RELEVANCE: As the Latarjet procedure is an emerging technique, it is essential to be aware of the anatomic structures and the relation between different neural structures to anatomic points of reference. Therefore, the results of this study add significant information for a safe surgical procedure for the majority of patients suffering from shoulder instability.