ABSTRACT
PURPOSE@#High explosives are used to produce blast waves to study their biological effects. The lungs are considered as the critical target organ in blast-effect studies. The degree of lung hemorrhaging is related to both the explosive power and the increased lung weight. We studied the characteristics of the biological effects from an air explosion of a thermobaric bomb in a high-altitude environment and the lethality and lung injury severity of goats in different orientations and distances.@*METHODS@#Goats were placed at 2.5, 3, 4, and 5 m from the explosion center and exposed them to an air blast at an altitude of 4700-meter. A group of them standing oriented to the right side and the other group seated facing the explosion center vertically. The lung injuries were quantified according to the percentage of surface area contused, and using the pathologic severity scale of lung blast injury (PSSLBI) to score the 4 injury categories (slight, moderate, serious and severe) as 1, 2, 3, and 4, respectively. The lung coefficient (lung weight [g]/body weight [kg]) was the indicator of pulmonary edema and was related to lung injury severity. Blast overpressure data were collected using blast test devices placed at matching locations to represent loadings to goats. All statistical analyses were performed using SPSS, version 26.0, statistical software (SPSS, Inc., Chicago, IL, USA).@*RESULTS@#In total, 127 goats were involved in this study. Right-side-standing goats had a significantly higher mortality rate than those seated vertical-facing (p < 0.05). At the 2.5 m distance, the goat mortality was nearly 100%, whereas at 5 m, all the goats survived. Lung injuries of the right-side-standing goats were 1 - 2 grades more serious than those of seated goats at the same distances, the scores of PSSLBI were significantly higher than the seated vertical-facing goats (p < 0.05). The lung coefficient of the right-side-standing goats were significantly higher than those of seated vertical-facing (p < 0.05). Mortality, PSSLBI, and the lung coefficient results indicated that the right-side-standing goats experienced severer injuries than the seated vertical-facing goats, and the injuries were lessened as the distance increased. The blast overpressure was consistent with these results.@*CONCLUSION@#The main killing factors of the thermobaric bomb in the high-altitude environment were blast overpressure, blast wind propulsions and burn. The orientation and distances of the goats significantly affected the blast injury severity. These results may provide a research basis for diagnosing, treating and protecting against injuries from thermobaric explosions.
Subject(s)
Animals , Lung Injury/etiology , Blast Injuries , Goats , Explosions , Lung/pathologyABSTRACT
Mechanical stimulation widely exists in the body and participates in adjusting biological behavior of many kinds of cells. As a common stress pattern in the body, the tensile strain widely exists in many organs, such as bone and cartilage, muscle tendon, cardiac and pulmonary vessels, and so on. In recent years, with the development of the researches of biomechanics, a variety of mechanical loading devices, which are used to simulate the complex mechanical stimulation in the body to provide the tensile strain including the isometric, uniaxial and various types of mechanical waveform, came into being. This is a huge boost to biomechanical research. Many researchers have found that the tensile strain stimulation can lead to the transformation of proliferation, differentiation and apoptosis of cells and change of cell matrix. However, for the same kind of cells, different kinds of tensile strain stimulation can lead to different and even the contrary results. In this paper, the effects of the tensile strain on the proliferation, differentiation and matrix of cartilage were reviewed. Understanding these characteristics will have important implications for the mechanism of cell proliferation and differentiation under the biomechanic stimulation and the prevention and treatment of diseases.
ABSTRACT
<p><b>OBJECTIVE</b>The receiver operator characteristic(ROC) curve was used to determine the best Blumensaat angle for the diagnosis of anterior cruciate ligament injury, so as to objectively evaluate the diagnostic value of Blumensaat angle for anterior cruciate ligament injury.</p><p><b>METHODS</b>Total 167 patients who had knee arthroscopic treatment in a hospital from January 2015 to January 2016 were retrospectively studied, and the patients' age, gender, left and right limb condition were recorded. The patients were divided into two groups according to Blumensaat angle measured on the MRI: group A(Blumensaat angle<=0°), and group B(Blumensaat angle >0°). The ROC curve was drawn from the statistical data of the group B to get the best critical value of the anterior cruciate ligament injury when the Blumensaat angle was more than 0°. According to the best critical value obtained by ROC curve, the coincidence rate of the total sample was obtained.</p><p><b>RESULTS</b>There were no significant differences in patients' age, gender, and affected limbs. There were 51 patients in group A, in which 49 patients were diagnosed as anterior cruciate injury under arthroscopy(gold standard for diagnosis of anterior cruciate ligament injury), and 2 patients were diagnosed as no anterior cruciate injury under arthroscopy. When the Blumensaat angle was<0°, the coincidence rate was 96.07%. In group B(116 cases), the area under the ROC curve was 0.910, the best cutoff corresponds to 15°; the sensitivity was 70.0%, and the specificity was 95.8%. When the Blumensaat angle was >=15°, the probability of anterior cruciate ligament injury was greater. When the Blumensaat angle was 0° to 15°, the anterior cruciate ligament was more likely to be not injured. The Blumensaat angle<=0°or>=15° were used to diagnose the injury of anterior cruciate ligament. Compared with the results of arthroscopy, the coincidence rate of the total sample was 92.8%.</p><p><b>CONCLUSIONS</b>Blumensaat angle is helpful to diagnose the ACL injuries. When the Blumensaat angle was <=0° or >=15°, the probability of ACL injury is greater.</p>
ABSTRACT
Patients who suffer from the recurrent patellar dislocation mainly show the recurrent dislocation of patellar, giving way, most patients have the history of trauma or dysplasia of keen joint. Traditional therapies of recurrent patellar dislocation include medical retinaculum placation, lateral retinaculum release, tibial tubercle osteotomy, femoral trochleoplasty etc. In recent years, with the development of anatomical and biomechanical researches on medial patellofemoral ligament(MPFL), more and more experts focus on the role of MPFL played in preventing the patellar dislocation. The treatment of recovering and correcting patellar tracking through MPFL reconstruction has been increasing gradually. However, till now, there was no therapy which could heal the recurrent patellar dislocation completely. The specific therapies of recurrent patellar dislocation are combination therapies, decided according to the anatomical and biomechanical conditions of patients, for recovering the stability of patients' patellar, the lower limb alignment and the function of keen-joint.