The discrepancy in triggered electromyography responses between fatty filum and normal filum terminale

BACKGROUND

Functional role of filum terminale (FT) was not well studied though it contains structure basis for nerve impulse conduction. We aimed to explore the possible functions of the FT from the perspective of triggered electromyography (EMG) during surgery.

METHODS

We retrospectively reviewed intraoperative neurophysiological monitoring data from pediatric patients who underwent intradural surgeries at the lumbar level in Shanghai Children's. Hospital from January 2018 to March 2023. Altogether 168 cases with complete intraoperative neurophysiological recordings of the FT were selected for further analysis. Triggered EMG recordings of the filum originated from two main types of surgeries: selective dorsal rhizotomy (SDR) and fatty filum transection.

RESULTS

96 cases underwent SDR and 72 cases underwent fatty filum transection. Electrical stimulation of the FT with fatty infiltration did not elicit electromyographic activity in the monitored muscles with the maximum stimulus intensity of 4.0 mA, while the average threshold for FT with normal appearance was 0.68 mA, and 89 out of 91 FT could elicit electromyographic responses in monitored channels. The threshold ratio of filum to motor nerve roots at the same surgical segment was significantly higher in patients with fatty filum, and a cut-off point of 21.03 yielded an area under curve of 0.943, with 100% sensitivity and 85.71% specificity.

CONCLUSION

Filum with normal appearance can elicit electromyographic activity in the lower limbs/anal sphincter similar to the performance of the cauda equina nerve roots. The threshold of fatty filum is different from that of normal appearing FT. Triggered EMG plays an important role in untethering surgeries.

Serum RGC-32 in children with systemic lupus erythematosus

Childhood-onset systemic lupus erythematosus (SLE) can be more severe than adult patients. Early diagnosis and accurate evaluation of the disease are very important for the patients. Response gene to complement-32 (RGC-32) protein is the downstream regulator of C5b-9 complex which is the terminal pathway of complement activation. Complement system plays a very important role in the pathogenesis of SLE. RGC-32 in patients with SLE has not been reported yet. We aimed to examine the clinical value of RGC-32 in children with SLE. A total of 40 children with SLE and another 40 healthy children were enrolled for this study. Clinical data were obtained prospectively. Serum RGC-32 was determined by ELISA. We found that serum RGC-32 was significantly elevated in children with SLE than that in the healthy group. Serum RGC-32 was significantly higher in the children with moderately/severely active SLE than that in the children with no/mildly active SLE. Furthermore, serum RGC-32 level correlated positively with C-reactive protein, erythrocyte sedimentation rate and ferritin and correlated negatively with white blood cell counts and C3. RGC-32 may be involved in the pathogenesis of SLE. RGC-32 might become a good biomarker in the diagnosis and evaluation of SLE.

Association between Intestinal Colonization and Extraintestinal Infection with Carbapenem-Resistant Klebsiella pneumoniae in Children

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a critical public health threat. However, the association between intestinal colonization and parenteral infection among pediatric patients has not been elucidated. We collected 8 fecal CRKP strains and 10 corresponding CRKP strains responsible for extraintestinal infection from eight patients who did not manifest infection upon admission to the hospital. Paired isolates showed identical resistance to antimicrobials and identical virulence in vitro and in vivo. wzi capsule typing, multilocus sequence typing, and whole-genome sequencing (WGS) indicated high similarity between paired colonizing and infecting isolates. Mutations between colonizing and infecting isolate pairs found by WGS had a distinctive molecular signature of a high proportion of complex structural variants. The mutated genes were involved in pathways associated with infection-related physiological and pathogenic functions, including antibiotic resistance, virulence, and response to the extracellular environment. The latter is important for bacterial infection of environmental niches. Various mutations related to antibiotic resistance, virulence, and colonization that were not associated with any particular mutational hot spot correlated with an increased risk of extraintestinal infection. Notably, novel subclone carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKP) KL19-ST15 exhibited hypervirulence in experimental assays that reflected the severe clinical symptoms of two patients infected with the clonal strains. Taken together, our findings indicate the association between CRKP intestinal colonization and extraintestinal infection, suggesting that active screening for colonization on admission could decrease infection risk in children. IMPORTANCE Carbapenem-resistant Klebsiella pneumoniae (CRKP) causes an increasing number of nosocomial infections, which can be life-threatening, as carbapenems are last-resort antibiotics. K. pneumoniae is part of the healthy human microbiome, and this provides a potential advantage for infection. This study demonstrated that CRKP intestinal colonization is strongly linked to extraintestinal infection, based on the evidence given by whole-genome sequencing data and phenotypic assays of antimicrobial resistance and virulence. Apart from these findings, our in-depth analysis of point mutations and chromosome structural variants in patient-specific infecting isolates compared with colonizing isolates may contribute insights into bacterial adaptation underlying CRKP infection. In addition, a novel subclone of carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKP) was observed in the study. This finding highlights the importance of CRKP active surveillance among children, targeting in particular the novel high-risk CR-hvKP clone.