Optimal timing of a single dose of zoledronic acid to increase strength in rat fracture repair.

We hypothesized that ZA treatment would bolster fracture repair. In a rat model for closed fracture healing, a single dose of ZA at 0, 1, or 2 wk after fracture significantly increased BMC and strength of the healed fracture. Delaying the dose (1 or 2 wk after fracture) displayed superior results compared with dosing at the time of fracture. INTRODUCTION: Bisphosphonates are known to increase bone strength and thus the resistance to fracture by decreasing osteoclastic bone resorption. These properties may enable bisphosphonates to also increase the strength of fracture repair. Zoledronic acid (ZA) is a potent bisphosphonate with a high affinity for bone mineral, allowing bolus intravenous dosing in a range of indications. In this study, we examined the application of bolus dose ZA in endochondral fracture repair. MATERIALS AND METHODS: Carbon-14 labeled ZA was used in a closed rat fracture model. Rats were divided into five treatment groups (n = 25 per group): saline control, local ZA (0.01 mg/kg), and three systemic bolus ZA groups (0.1 mg/kg) with different administration times: at fracture, 1 wk after fracture, and 2 wk after fracture. Rats were killed 6 wk postoperatively. Postmortem analyses included radiography, QCT, microCT, biomechanical testing, scintillation counting, autoradiography, and histology. RESULTS: Single-dose systemic ZA administration significantly increased callus volume, callus BMC, and mechanical strength. Perioperative treatment increased mechanical strength by 30% compared with controls (p < 0.05). Administering the systemic dose at 1 or 2 wk after fracture further increased mechanical strength compared with controls by 44% and 50%, respectively (p < 0.05). No significant differences in mechanical parameters were seen with local injection at the dose studied. Autoradiographic analysis indicated that ZA binds significantly to bone that is present at the time of administration. ZA quantification indicated that delayed administration significantly increased the uptake efficiency in the callus. Histological and microCT analysis showed that ZA treated calluses had a distinctive internal structure consisting of an intricate network of retained trabecular bone. CONCLUSIONS: The timing of a single systemic dose of ZA plays an important role in the modulation of callus properties in this rat fracture model; delaying the single dose produces a larger and stronger callus.     

Microanatomical study of testis in juvenile ostrich (Struthio camelus)

The majority of investigations on the testis, as the main organ of male reproductive system, have been performed in mammalian species, with few studies on bird species. Thus, the structure of the ostrich testis remains largely unknown. The aim of this study was to investigate the microanatomical characteristics of the testis in five juvenile ostriches. A stereological study was performed according to the Delesse principle. The mean volume fraction of the seminiferous tubules was 0.569, and the mean volume of the seminiferous tubules in an average testis was 1.04 cm³. The Paraffin-embedded sections were stained with hematoxylin and eosin, Masson’s trichrome, Alcian blue, and periodic acid–Schiff stains. Histological studies revealed that the spermatogonial stem cells and Sertoli cells were localized inside the seminiferous tubules, close to the basement membrane. Inside the tubules a few meiotic cells up to the spermatozoa stage were located in a centripetal manner. Outside the tubules, one to three layers of euchromatic peritubular myoid cells were present, surrounded by loose interstitial connective tissue. A thick tunica albuginea contained many myoid cells and some rete ducts, with the latter extending from the hilus to the free surface of the testis. Straight seminiferous tubules were distributed in the lateral surfaces and hilar portions of the capsule but were rare in the free surface. These capsular rete ducts may participate in testicular fluid transit from the distal tubules through the capsule.     

The associations between noise annoyance and psychological distress with blood pressure in children and adolescents: The CASPIAN‐V Study

Although blood pressure (BP) tracks from childhood to adulthood, and the prevalence of pediatric primary hypertension is increasing, related determinants are not well understood. The role of noise pollution and psychological distress in increasing BP is well documented in adults, but it remains elusive in children. This study aims to investigate the association of noise annoyance and psychological distress with BP in a pediatric population. This national cross‐sectional study was conducted in 2015 on a sample of 14400 Iranian students, aged 7‐18 years. Information regarding noise annoyance and psychological distress were assessed using questionnaires, and BP values were measured. Levels of noise annoyance and psychological distress were classified based on tertiles to no/low, moderate, and high. Data of 14274 students were completed. The mean age of participants was 12.28 (0.05), with 51% boys and 71.4% urban inhabitant. Diastolic BP and mean arterial BP (MAP) had positive correlations with noise annoyance (regression coefficient: 0.028, 95 % CI: 0.005 ‐ 0.05 and 0.025, 95 % CI: 0.002 – 0.04, respectively). Participants with higher psychological distress were 15 % more likely to experience abnormally high BP compared to those with normal psychological status or mild distresses (OR: 1.15, 95 % CI: 1.003 – 1.34). Here, we found significant positive relationships between the level of noise annoyance and values of diastolic BP and MAP. Moreover, high psychological distress showed to increase the chance of abnormally high BP. The clinical impact of these findings should be assessed in further longitudinal studies.