Analysis of absolute amounts of two meiotic cohesin subunits, RAD21L and REC8, in mouse spermatocytes.

RAD2lL and REC8, meiosis-specific paralogs of the canonical cohesin subunit RAD21, are essential for proper formation of axial/lateral elements of the synaptonemal complex, synapsis of homologous chromosomes, and crossover recombination in mammalian meiosis. However, how many meiotic cohesins are present in germ cells has not been investigated because of the lack of an appropriate method of analysis. In the present study, to examine the intracellular amount of meiotic cohesins, we generated two strains of knock-in (KI) mice that expressed a 3×FLAG-tag at the C-terminus of RAD21L or REC8 protein using the CRISPR/Cas9 genome editing system. Both KI mice were fertile. Western blot analyses and immunocytochemical studies revealed that expression levels and localization patterns of both RAD21L-3×FLAG and REC8-3×FLAG in KI mice were similar to those in wild-type mice. After confirming that tagging of endogenous RAD21L and REC8 with 3×FLAG did not affect their expression profiles, we evaluated the levels of RAD21L-3×FLAG and REC8-3×FLAG in the testes of 2-week-old mice in which only RAD21L and REC8 but little RAD21 are expressed in the meiocytes. By comparing the band intensities of testicular RAD21L-3×FLAG and REC8-3×FLAG with 3×FLAG-tagged recombinant proteins of known concentrations in western blot analysis, we found that there were approximately 413,000 RAD21L and 453,000 REC8 molecules per spermatocyte in the early stages of prophase I. These findings provide new insights into the role played by cohesins in the process of meiotic chromosome organization in mammalian germ cells.

Soil selenium enrichment in the Loess Plateau of China: Geogenic evidence, spatial distribution, and it's influence factors.

The selenium (Se)-deficient soil belt in China has gained widespread attention. During large-scale soil surveys in China, Se-rich soils within low-Se belts have been identified. However, the sources of Se in those soils and the controlling factors for their enrichment remain unclear. Here we summarize Se concentrations and spatial distributions in the Yuanzhou district of the Loess Plateau. We evaluated Se variations in soil profiles, Se migration into water bodies, and considered soil indicators, topographic characteristics and the influence of land-use types on soil Se concentrations. The average Se concentration in the topsoil of the Yuanzhou district was 0.164 µg/g. High-Se soils (>0.222 µg/g) were found in the western valley plain and the southern red bed hilly area, as well as sporadically in higher elevation forestland and grassland areas in the east. Enrichment of Se in the topsoil in the eastern and southern areas was primarily due to Se adsorption and accumulation by soil organic matter as well as enrichment in gypsum, berlinite, and clay minerals during soil formation. Widespread enrichment in the southern area was linked to high Se concentrations in red Tertiary sedimentary rocks. In the western area, enrichment of Se in topsoil was found on both sides of the Qingshui River at low elevations with gentle slopes, with river water being the primary carrier of Se enrichment. These findings provide valuable insights into the epigenetic geochemical behavior of soil Se in China's low-Se belt that accounts for development of Se-rich soils in the region.

Early Rehabilitation and Periprosthetic Bone Environment after Primary Total Hip Arthroplasty: A Randomized Controlled Trial.

OBJECTIVE: To investigate whether the periprosthetic bone environment could be affected by activity during the early rehabilitation period after primary total hip arthroplasty (THA) and to evaluate the safety and efficacy of activity during the early rehabilitation period. METHODS: This random clinical trial was conducted from January 2017 to July 2017. A total of 22 selected patients with advanced osteonecrosis of the femoral head (ONFH) who underwent primary unilateral THA were randomized (1:1) to a high activity level group (HA group) or a low activity level group (LA group). The HA group included nine men and two women, aged 53.18 ± 13.29 years. The LA group included five men and six women, aged 55.73 ± 11.73 years. The intervention was different postoperative daily walking distances guided by researchers: 1727.27 ± 564.08 m 0-2 months and 4272.73 ± 904.53 m 3-6 months postoperation for the HA group and 909.09 ± 583.87 m 0-2 months and 2409.09 ± 1068.13 m 3-6 months postoperation for LA group. The primary outcomes were radiographic evaluation (prosthetic stability and stress shielding based on the Engh scale) and bone mineral density (BMD) with a femoral prosthesis (individual and intergroup comparison using seven Gruen zones) at 6 months postoperatively. Secondary outcomes were set to confirm the safety and efficacy of activity during early rehabilitation, including day 1 erythrocyte sedimentation rate (ESR), day 1 hypersensitive C-reactive protein (CRP), length of hospital stay (LOS), and the Harris hip score (HHS) at discharge, 2 months postoperatively, and 6 months postoperatively. RESULTS: Patients were followed up for 6 months after surgery. Regarding primary outcomes, all prostheses were assessed as stable, with bone in-growth. There were no adverse events in any cases. The HA group had a higher incidence of stress shielding than the LA group, but there was no statistical significance (63.64% vs 18.18%; P > 0.05). The degree of stress shielding had a different distribution for the two groups (P < 0.05). In the HA group and the LA group, the median percentage difference of the BMD on the operated side was -25% and was -13% in Zone 1, -8% and - 1% in Zone 2, +1% and 3% in Zone 3, +6% and + 6% in Zone 4, -2% and +2% in Zone 5, -3% and -1% in Zone 6, and -24% and -12% in Zone 7 compared with the unoperated side. The BMD was significantly reduced in the medial proximal femur (Zone 1) and the lateral proximal femur (Zone 7) in both groups (P < 0.05). Furthermore, it was increased in the distal femur (Zone 4) in the HA group (P < 0.05). No difference was found in the BMD when comparing between groups. Regarding secondary outcomes, there was no statistical difference in day 1 ESR and day 1 CPR. The average LOS was similar in the HA and LA groups (7.00 days vs 7.18 days, P > 0.05). The HHS on day of discharge was higher in the HA group than in the LA group (60.73 ± 5.37 points vs 51.18 ± 8.05 points, P < 0.05); however, no statistically significant difference was found in postoperative the HHS at 2 months (81.73 ± 6.92 points vs 78.36 ± 9.18 points, P > 0.05) and 6 months (90.45 ± 5.24 points vs 91.55 ± 4.03 points, P > 0.05). CONCLUSION: High activity levels during early rehabilitation after primary THA accelerate the process of bone remodeling and aggravate stress shielding, with no significant benefits for functional recovery.