[The value of dehydroepiandrosterone sulfate in the differential diagnosis of primary bilateral adrenal macronodular hyperplasia].

Objective: To investigate the value of serum dehydroepiandrosterone sulfate (DHEAS) in the differential diagnosis of primary bilateral macronodular adrenal hyperplasia (PBMAH) from nonfunctional adenoma tumors (NFA), adrenocortical adenoma (ADA) and Cushing's disease (CD). Methods: A cross-sectional study. The clinical data of 302 patients with PBMAH, NFA, ADA and CD diagnosed and treated in the First Medical Center of PLA General Hospital from January 2010 to June 2021 were retrospectively analyzed. Among them, 97 were males and 205 were females, aged (45.7±7.2) years. The area under receiver operating characteristic (ROC) curve was used to evaluate the DHEAS ratio (serum DHEAS value divided by the lower limit of normal reference range for the corresponding age and sex) and the 8∶00 adrenocorticotropic hormone (ACTH) level in the differential diagnosis of PBMAH from NFA, ADA and CD. The maximum value of Youden index was cut-off value. Results: Among the 302 patients, 33 were in PBMAH group, 125 were in NFA group, 67 were in ADA group, and 77 were in CD group. The DHEAS ratio in CD group, NFA group, PBMAH group and ADA group decreased successively, with values of 6.34(4.44, 9.93), 3.37(2.24, 4.79), 1.14(1.04, 2.40) and 0.58(0.27, 1.05), respectively. There was statistical significance among all groups (all P<0.01). The area under the ROC curve for distinguishing PBMAH from NFA, ADA and CD were 0.803, 0.741 and 0.930, and the cut-off value were 2.59, 0.99 and 2.92, respectively. The sensitivity was 66.1%, 64.2% and 87.9%, respectively. The specificity was 81.8%, 81.2% and 85.7%. According to the level of 8∶00 ACTH, PBMAH was divided into ACTH-inhibited group (ACTH<2.2 pmol/L,n=18) and ACTH-non-inhibited group (ACTH≥2.2 pmol/L, n=15).The DHEAS ratio in ACTH-non-inhibited PBMAH group was higher than that in ACTH-inhibited PBMAH group(P<0.01).The area under ROC curve of DHEAS ratio for identifying ACTH-non-inhibited PBMAH and CD was 0.877, the cut-off value was 4.55, the sensitivity was 93.3%, and the specificity was 75.3%. If the DHEAS ratio combined with 8∶00 ACTH was used as a differential diagnostic indicator, the area under the ROC curve for distinguishing ACTH-non-inhibitory PBMAH from CD can reach 0.967, with the sensitivity of 100.0% and the specificity of 81.8%. Conclusions: DHEAS ratios is different in PBMAH, NFA, ADA and CD patients, which can assist in the differential diagnosis of PBMAH from NFA、ADA and CD patients, especially in the differential diagnosis of ACTH-non-inhibited PBMAH patients and CD patients.

Molecular cloning and characterization of a short peptidoglycan recognition protein from silkworm Bombyx mori.

Peptidoglycan is the major bacterial component recognized by the insect immune system. Peptidoglycan recognition proteins (PGRPs) are a family of pattern-recognition receptors that recognize peptidoglycans and modulate innate immune responses. Some PGRPs retain N-acetylmuramoyl-L-alanine amidase (Enzyme Commission number: 3.5.1.28) activity to hydrolyse bacterial peptidoglycans. Others have lost the enzymatic activity and work only as immune receptors. They are all important modulators for innate immunity. Here, we report the cloning and functional analysis of PGRP-S4, a short-form PGRP from the domesticated silkworm, Bombyx mori. The PGRP-S4 gene encodes a protein of 199 amino acids with a signal peptide and a PGRP domain. PGRP-S4 was expressed in the fat body, haemocytes and midgut. Its expression level was significantly induced by bacterial challenges in the midgut. The recombinant PGRP-S4 bound bacteria and different peptidoglycans. In addition, it inhibited bacterial growth and hydrolysed an Escherichia coli peptidoglycan in the presence of Zn2+ . Scanning electron microscopy showed that PGRP-S4 disrupted the bacterial cell surface. PGRP-S4 further increased prophenoloxidase activation caused by peptidoglycans. Taken together, our data suggest that B. mori PGRP-S4 has multiple functions in immunity.