[Classification of tracheobronchial tuberculosis in 252 children].

Objective: To provide theoretical basis for early diagnosis and accurate bronchoscopic classification of tracheobronchial tuberculosis (TBTB) in children through analyzing the clinical characteristics, bronchoscopic classifications and treatment effect in children with TBTB. Methods: In this respective study, we collected clinical data of patients with TBTB who accepted bronchoscopies in Interventional Pulmonology Department of Beijing Children's Hospital Affiliated to Capital Medical University between January, 2006 and December, 2019. The basic data, including clinical manifestations, imaging features, bronchoscopic characteristics and effects of interventional therapy were analyzed. The results of the study were statistically described and analyzed using SPSS 22.0 statistical software for relevant data. Results: Total 252 children with TBTB were included in this study. The median age was 1.7 years (quartile: 0.8 years, 5.2 years). Analysis of the classification of TBTB showed that the percent of lymph node fistula type was 96.4% (243/252), ulcerative necrosis type 1.2%(3/252), granulation proliferation type 0.4% (1/252), and cicatricial stricture type 0.8% (2/252). In addition, 1.2% (3/252) of the cases showed the same bronchoscopic manifestations as lymph node fistula type, but it was not clear on imaging whether the caseous material in the lumen was caused by lymph node or lung erosion. Therefore, the "bronchial fistula type" was proposed. Conclusions: Lymph node fistula type of TBTB was the common in children. The classification of lymph node fistula mostly depended on imaging evidence, and this may lead to some uncertainty in classifying TBTB in cases with no imaging evidence of enlarged lymph nodes.

Stress analysis during jaw movement based on vivo computed tomography images from patients with temporomandibular disorders.

The purpose of this study is to develop three-dimensional (3D) finite element models of temporomandibular joints (TMJs) and to investigate stress distributions. To determine the causes of temporomandibular disorders (TMDs), the magnitude and location of the maximum stresses under physiological loading must be considered. Stress analysis TMD models were reconstructed from computed tomography (CT) data. Several studies have investigated finite element TMJ models, but few have used a bilateral mandible model that includes jaw closing and maximum opening. In this study, the authors defined an asymmetry index for the different stress values on each side joint; this index has not yet been investigated. According to clinical observation, one joint affects the other side joint during mastication. Three symptom-free volunteers and three symptomatic patients were selected as the control group (CG) and TMD group (TG), respectively. For the TG, data analysis indicated that the condyle was asymmetrical during jaw closing, while both the condyle and disc were slightly asymmetrical during jaw opening. The maximum stresses did not significantly differ between the CG and TG for either closing or opening of the jaw. The results of this study have a potential clinical benefit in terms of proving superior biomechanical behaviour.

Receptor binding dependent structural changes in human choriogonadotropin: photochemical inter-subunit crosslinking.

Activation of surface receptors is thought to occur in multiple transient steps with conformational adjustments of hormones and receptors beginning from the initial hormone-receptor contact. In this study, we have established a sensitive photochemical crosslinking method to detect structural change of hCG upon receptor binding. hCG consists of an α subunit and a ß subunit. Free α subunit was derivatized with photosensitive reagents and reassociated with unmodified ß subunit. Reassociated hCG αß dimer was capable of high affinity receptor binding and activation. The reagents attached to the α subunit were capable of crosslinking the α subunit to the ß subunit. However, the extent of inter-subunit cross-linking in solution was two-three fold greater than inter-subunit crosslinking after hCG bound to the receptor. This difference indicates a novel structural change at the subunit interface in response to hCG binding to the receptor. Although highly unlikely, other microenvironmental factors might have interfered with the crosslinking efficiency without impacting the structure of hCG. This study lays the ground work to precisely define the location and nature of the change. Such information will be crucial for the understanding of the molecular mechanism of the hormone-receptor interaction and receptor activation.