Comparative analysis of pathological structure between acute closed and open Achilles tendon rupture / 中国骨伤

OBJECTIVE@#To investigate the morphological, histological and ultrastructural changes of acute closed rupture of Achilles tendon, in order to clarify the pathological basis of the injury and to explore the significance.@*METHODS@#From January 2015 to January 2019, 35 patients with acute Achilles tendon rupture who underwent the minimally invasive Achilles tendon suture technique were retrospectively analyzed. Among these patients, 12 cases in acute open Achilles tendon rupture group included 10 males and 2 females, with an average age of (35.1±9.7) years old ranging from 19 to 50, and the time from injury to operation was 2 to 8 hours with an average of(5.6±1.8);23 cases in acute closed Achilles tendon rupture group included 21 males and 2 females, with an average age of (35.5±6.6) years old ranging from 18 to 50, and the time from injury to operation was 3 to 15 hours with an average of (7.5±3.1). The gross appearance and imaging findings of the broken end of Achilles tendon tissue in the two groups were compared by naked eye observation and foot and ankle MRI at 4 to 6 hours before operation. HE staining, scanning and fluoroscopic electron microscopy, immunohistochemistry(Sirius red staining) were performed on the intraoperative Achilles tendon tissue specimens at 1 to 2 days after operation, the collagen fiber degeneration and local fat infiltration, collagen fiber shape, cell morphology and function, and the distribution of typeⅠand type Ⅲ collagen fibers in Achilles tendon were compared between the two groups.@*RESULTS@#Compared with the acute open Achilles tendon rupture group, the acute closed Achilles tendon rupture group had poor elasticity, hard texture, moderate edema, irregular shape of Achilles tendon broken end, horsetail shape, and more calcification around the broken end. HE staining results:the collagen fibers in the Achilles tendon of the acute open Achilles tendon rupture group were arranged irregularly, with hyaline degeneration and fat infiltration;The results of electron microscopy showed that collagen arranged disorderly and fibroblasts atrophied in the acute closed Achilles tendon rupture group. Immunohistochemical(Sirius staining) results:the proportion of collagenⅠin the acute open Achilles tendon rupture group and the acute closed Achilles tendon rupture group was(91.12±4.34)% and(54.71±17.78)% respectively, and the proportion of collagen Ⅲ was (8.88±4.34)% and (45.29±17.78)% respectively. The content of collagenⅠin the acute closed Achilles tendon rupture group was lower than that in the acute open Achilles tendon rupture group, and the content of collagen Ⅲ in the acute closed Achilles tendon rupture group was higher than that in the acute open Achilles tendon rupture group(P<0.05).@*CONCLUSION@#The morphology, histology and ultrastructure of the acute closed ruptured Achilles tendon are significantly altered compared with the normal Achilles tendon. The original fine and orderly spatial structure cannot be maintained, part of collagen Ⅰ is replaced by collagen Ⅲ, and the toughness and strength of the tendon tissue decreased, which may be the feature of degeneration of the Achilles tendon and an important pathological basis for closed Achilles tendon rupture.

Effects of effluent recirculation in vertical-flow constructed wetland on treatment efficiency of livestock wastewater.

Enhancing the treatment efficiency of livestock wastewater by effluent recirculation is investigated in a pilot-scale vertical-flow constructed wetland. The wetland system is composed of downflow and upflow stages, on which narrow-leaf Phragmites communis and common reed Phragmites typhia are planted, respectively; each stage has a dimension of 4 m(2) (2 m x 2 m). Wastewater from the facultative pond is fed into the system intermittently at a flow rate of 0.4 m(3)/d. Recirculation rates of 0, 25%, 50%0, 100% and 150% are adopted to evaluate the effect of the recirculation rate on pollutants removal. This shows that with effluent recirculation the average removal efficiencies of NH4-N, BOD5 and SS obviously increase to 61.7%, 81.3%, and 77.1%, respectively, in comparison with the values of 35.6%o, 50.2%, and 49.3% without effluent recirculation. But the improvement of TP removal is slight, only from 42.3% to 48.9%. The variations of NH4-N, DO and oxidation-reduction potential (ORP) of inflow and outflow reveal that the adoption of effluent recirculation is beneficial to the formation of oxide environment in wetland. The exponential relationships with excellent correlation coefficients (R(2) > 0.93) are found between the removal rates of NH4-N and BOD5 and the recirculation rates. With recirculation the pH value of the outflow decreases as the alkalinity is consumed by the gradually enhanced nitrification process. When recirculation rate is kept constant at 100%, the ambient temperature appears to affect NH4-N removal, but does not have significant influence on BOD5 removal.