Animal models of ovariectomy in rats demonstrate characteristics similar to early stage osteoarthritis

Purpose The aim of our study is to analyze the model of ovariectomy (OVX) in rats reproduced histological changes of osteoarthritis (OA). Methods For the development of the research, 12 Wistar rats were used, divided into 2 equal groups: Control Group - C (n = 6) and Osteoarthritis Group - OA (n = 6). After the 6-month experimental period, all rats were sacrificed and, subsequently, the entire knee joint complex was removed without disarticulation. For the histological evaluation of the tissue, the recommendations of the International Society for Research in OA (OARSI) were used. For data processing, each evaluation was statistically treated in both groups, comparing data from group C with the group OA. Results: Through the histological evaluation of OARSI, the evolution of OA in various tissues of the joint was evaluated. Although the OA group showed noticeable differences from group C, they were not as significant. Thus, only statistically significant favors were presented in the loss of the cartilaginous matrix (OA and C, p = 0.51), considering that the changes in the loss of ECM occurred only at the depth of 0% (superficial region), but at the depth of 50% (intermediate region) and 100% depth (deep region) did not exist. Conclusion Our study demonstrated that the OVX model is a good model to discuss OA, showing histological changes similar to those found in OA, the model demonstrated to have a progressive and slow characteristic since after the OARSI evaluations, prominent evidence was found in the initial manifestations of OA.

Biological response to wind and terrestrial nitrate in the western and southern continental shelves of the Gulf of Mexico

In Mexico, 16 rivers directly discharge into the Gulf of Mexico. The Mexican rivers and those coming from the United States generate large regions in which phytoplanktonic primary production possesses a seasonal component that is linked to these nutrient-rich freshwater inputs. In the present study, new flow and daily nutrient data were obtained for the largest Mexican rivers. These data were integrated as forcing factors in a configuration of the hydrodynamic Coastal and Regional Ocean COmmunity model coupled to an N2PZD2 biogeochemical model. To correctly represent biological processes in coastal regions, a biological bottom condition was implemented in the biogeochemical model. With this condition, it was possible to represent remineralization on the continental shelf of the Gulf of Mexico. We present a 21 year simulation using two different configurations. The first included river forcing, and the second did not consider their influence. The results were validated with satellite images of the surface concentration of chlorophyll and compared with data from previous studies. The coupled model was able to realistically reproduce the seasonal dynamics of primary production in the Gulf of Mexico based on the concentration and distribution of chlorophyll, both at the surface and in the water column. Finally, the physical processes that influence the dynamics of primary production in the deep region and continental shelf of the gulf were defined. In the deep region, primary production was dominated by vertical mixing induced by the passage of cold fronts during winter and mesoscale structures. On the continental shelf, such dynamics were dominated by coastal upwelling and fluvial nutrient contributions.

Stress state inferred from b-value and focal mechanism distributions in the aftershock area of the 2005 West Off Fukuoka Prefecture earthquake

The spatiotemporal stress states in the aftershock region of the 2005 west off Fukuoka prefecture earthquake are examined via an analysis of the b -values and focal mechanism solutions. The aftershocks are aligned roughly NW–SE, with the southeastern part of the aftershock region believed to correspond to Kego Fault, which extends beneath the Fukuoka metropolitan area. This study reveals depth-dependent b -values in the focal region, where the b -values ( b = 0.7–1.4) are generally higher above the mainshock depth (9.5 km) and lower ( b = 0.5–1.0) at greater depths. The shallower region possesses a significant temporal increase in b -values, whereas a lateral b -value heterogeneity is observed in the deeper region. The b -values ( b ~ 1.0) near the mainshock are relatively high, whereas the northwestern and southeastern edges of the deep region have lower b -values ( b = 0.5–0.7). On the other hand, many of the focal mechanisms for the M ≥ 3.5 events are located in the low b -value area of the deep region. The stress-tensor inversion results reveal a change in stress state from strike-slip to strike-slip/normal faulting . These findings imply that the stress state remains high and/or slightly decreased in the northwestern and southeastern parts of the deep region. These results and the findings of previous research on this earthquake sequence suggest that the likelihood of future large earthquakes along the southeastern part of the aftershock region should be considered relatively high.

Aquatic oligochaetes (Annelida: Clitellata) in reservoirs in São Paulo State: list of occurrence and ecological observations on the species

This work sought the survey of species and information about the distribution of the Class Oligochaeta in reservoirs sampled in the Sediment Quality Monitoring Network of CETESB (Environmental Company of the State of São Paulo). As such, this study aimed to inventory the limnic oligochaetes fauna to expand knowledge of the ecology and distribution of this group in reservoirs in the state of São Paulo. Ninety replicates were performed in 12 reservoirs in the state of São Paulo between 2014 and 2016, using van Veen or Ponar samplers in the sublittoral region, and Ekman-Birge in the deep region. Twenty-eight taxa were inventoried, belonging to the families Naididae and Opistocystidae. The species Dero righii and Pristina longisoma were recorded for the first time in São Paulo State, Nais magnaseta and Spirosperma velutina were first recorded in Brazil. The results presented here make this inventory extremely important for understanding the distribution of aquatic oligochaetes throughout the Brazilian territory.

Regional differences between superficial and deep lumbar multifidus in patients with chronic lumbar spine pathology

Background Due to its unique arrangement, the deep and superficial fibers of the multifidus may have differential roles for maintaining spine stabilization and lumbar posture; the superficial multifidus is responsible for lumbar extension and the deep multifidus for intersegmental stability. In patients with chronic lumbar spine pathology, muscle activation patterns have been shown to be attenuated or delayed in the deep, but not superficial, multifidus. This has been interpreted as pain differentially influencing the deep region. However, it is unclear if degenerative changes affecting the composition and function of the multifidus differs between the superficial and deep regions, an alternative explanation for these electrophysiological changes. Therefore, the goal of this study was to investigate macrostructural and microstructural differences between the superficial and deep regions of the multifidus muscle in patients with lumbar spine pathology. Methods In 16 patients undergoing lumbar spinal surgery for degenerative conditions, multifidus biopsies were acquired at two distinct locations: 1) the most superficial portion of muscle adjacent to the spinous process and 2) approximately 1 cm lateral to the spinous process and deeper at the spinolaminar border of the affected vertebral level. Structural features related to muscle function were histologically compared between these superficial and deep regions, including tissue composition, fat fraction, fiber cross sectional area, fiber type, regeneration, degeneration, vascularity and inflammation. Results No significant differences in fat signal fraction, muscle area, fiber cross sectional area, muscle regeneration, muscle degeneration, or vascularization were found between the superficial and deep regions of the multifidus. Total collagen content between the two regions was the same. However, the superficial region of the multifidus was found to have less loose and more dense collagen than the deep region. Conclusions The results of our study did not support that the deep region of the multifidus is more degenerated in patients with lumbar spine pathology, as gross degenerative changes in muscle microstructure and macrostructure were the same in the superficial and deep regions of the multifidus. In these patients, the multifidus is not protected in order to maintain mobility and structural stability of the spine.

Regional differences between superficial and deep lumbar multifidus in patients with chronic lumbar spine pathology

Background: Due to its unique arrangement, the deep and superficial fibers of the multifidus may have differential roles for maintaining spine stabilization and lumbar posture; the superficial multifidus is responsible for lumbar extension and the deep multifidus for intersegmental stability. In patients with chronic lumbar spine pathology, muscle activation patterns have been shown to be attenuated or delayed in the deep, but not superficial, multifidus. This has been interpreted as pain differentially influencing the deep region. However, it is unclear if degenerative changes affecting the composition and function of the multifidus differs between the superficial and deep regions, an alternative explanation for these electrophysiological changes. Therefore, the goal of this study was to investigate macrostructural and microstructural differences between the superficial and deep regions of the multifidus muscle in patients with lumbar spine pathology.Methods: In 16 patients undergoing lumbar spinal surgery for degenerative conditions, multifidus biopsies were acquired at two distinct locations: 1) the most superficial portion of muscle adjacent to the spinous process and 2) approximately 1 cm lateral to the spinous process and deeper at the spinolaminar border of the affected vertebral level. Structural features related to muscle function were histologically compared between these superficial and deep regions, including tissue composition, fat fraction, fiber cross sectional area, fiber type, regeneration, degeneration, vascularity and inflammation. Results: No significant differences in fat signal fraction, muscle area, fiber cross sectional area, muscle regeneration, muscle degeneration, or vascularization were found between the superficial and deep regions of the multifidus. Total collagen content between the two regions was the same. However, the superficial region of the multifidus was found to have less loose and more dense collagen than the deep region. Conclusions: The results of our study did not support that the deep region of the multifidus is more degenerated in patients with lumbar spine pathology, as gross degenerative changes in muscle microstructure and macrostructure were the same in the superficial and deep regions of the multifidus. In these patients, the multifidus is not protected in order to maintain mobility and structural stability of the spine.

Regional differences between superficial and deep lumbar multifidus in patients with chronic lumbar spine pathology

Background: Due to its unique arrangement, the deep and superficial fibers of the multifidus may have differential roles for maintaining spine stabilization and lumbar posture; the superficial multifidus is responsible for lumbar extension and the deep multifidus for intersegmental stability. In patients with chronic lumbar spine pathology, muscle activation patterns have been shown to be attenuated or delayed in the deep, but not superficial, multifidus. This has been interpreted as pain differentially influencing the deep region. However, it is unclear if degenerative changes affecting the composition and function of the multifidus differs between the superficial and deep regions, an alternative explanation for these electrophysiological changes. Therefore, the goal of this study was to investigate macrostructural and microstructural differences between the superficial and deep regions of the multifidus muscle in patients with lumbar spine pathology.Methods: In 16 patients undergoing lumbar spinal surgery for degenerative conditions, multifidus biopsies were acquired at two distinct locations: 1) the most superficial portion of muscle adjacent to the spinous process and 2) approximately 1 cm lateral to the spinous process and deeper at the spinolaminar border of the affected vertebral level. Structural features related to muscle function were histologically compared between these superficial and deep regions, including tissue composition, fat fraction, fiber cross sectional area, fiber type, regeneration, degeneration, vascularity and inflammation. Results: No significant differences in fat signal fraction, muscle area, fiber cross sectional area, muscle regeneration, muscle degeneration, or vascularization were found between the superficial and deep regions of the multifidus. Total collagen content between the two regions was the same. However, the superficial region of the multifidus was found to have less loose and more dense collagen than the deep region. Conclusions: The results of our study did not support that the deep region of the multifidus is more degenerated in patients with lumbar spine pathology, as gross degenerative changes in muscle microstructure and macrostructure were the same in the superficial and deep regions of the multifidus. In these patients, the multifidus is not protected in order to maintain mobility and structural stability of the spine.