In reply to the letter to the editor regarding "Clinical outcomes of teeth adjacent to the site of mandibulotomy or mandibulectomy in patients with head and neck cancer: results from a multidisciplinary mono-institutional head and neck tumor board".

This paper aims to reply to Somay et al., regarding their comment to a previous paper from our group, titled "Clinical outcomes of teeth adjacent to the site of mandibulotomy or mandibulectomy in patients with head and neck cancer: results from a multidisciplinary mono-institutional head and neck tumor board".The following concerns were addressed: 1) Within the limits of a case series, mandibulectomy might be considered a risk factor for the loss of tooth vitality as well as mandibulotomy. 2) Root canal therapy before surgery on the teeth adjacent to the surgical site could be an appropriate strategy, although in some cased it may involve teeth which are not destinate to have endodontic complications. 3) Dose-volume data of the included teeth were provided: the impact of radiotherapy (RT) as a confounding factor seems not to be as relevant as Somay et al. have pointed out.

Oncologic and perioperative outcomes of laparoscopic versus open radical nephrectomy for the treatment of renal tumor (> 7 cm): a systematic review and pooled analysis of comparative outcomes.

OBJECTIVE: Systematic evaluation of the effectiveness and safety of laparoscopic radical nephrectomy (LRN) for renal tumor (>7 cm). METHODS: The databases PubMed, Scopus, SinoMed, ScienceDirect, and Google Scholar were systematically searched for trials up to November 2022. The pooled results were evaluated by weighted mean difference (WMD), odds ratio (OR), and hazard ratio (HR). RESULTS: This meta-analysis (18 trials) demonstrated that compared to open radical nephrectomy (ORN), LRN had a longer operative time (OT) (WMD=15.99, 95% CI: 6.74 to 25.24, p = 0.0007), lower estimated blood loss (EBL) (WMD = -237.07, 95% CI: -300.02 to -174.12, p < 0.00001), lower transfusion rates (OR = 0.37, 95% CI: 0.24 to 0.55, p < 0.00001), and shorter length of stay (LOS) (WMD = -2.95, 95% CI: -3.86 to -2.03, p < 0.00001). No statistically relevant differences were found in overall survival (OS) (HR = 1.04, 95% CI: 0.81 to 1.35, p = 0.76), cancer-specific survival (CSS) (HR = 1.28, 95% CI: 0.97 to 1.68, p = 0.08), progression-free survival (PFS) (HR = 1.20, 95% CI 0.97 to 1.48, p = 0.1), recurrence-free survival (RFS) (OR = 1.27, 95% CI: 0.89 to 1.81, p = 0.56), local recurrence rate (OR = 0.85, 95% CI: 0.42 to 1.71, p = 0.65), and intraoperative and postoperative complications. CONCLUSION: For patients with renal tumors (> 7 cm), LRN has specific perioperative advantages over ORN (LOS, EBL, and transfusion rates). However, the OT was prolonged in the LRN group. In addition, no differences in complication or oncological outcomes (OS, CSS, PFS, RFS, and local recurrence rate) were reported. TRIAL REGISTRATION: PROSPERO CRD42022367114.

NrnA Is a Linear Dinucleotide Phosphodiesterase with Limited Function in Cyclic Dinucleotide Metabolism in Listeria monocytogenes.

Listeria monocytogenes produces both c-di-AMP and c-di-GMP to mediate many important cellular processes, but the levels of both nucleotides must be regulated. c-di-AMP accumulation attenuates virulence and diminishes stress response, and c-di-GMP accumulation impairs bacterial motility. An important regulatory mechanism to maintain c-di-AMP and c-di-GMP homeostasis is to hydrolyze them to the linear dinucleotides pApA and pGpG, respectively, but the fates of these hydrolytic products have not been examined in L. monocytogenes. We found that NrnA, a stand-alone DHH-DHHA1 phosphodiesterase, has a broad substrate range but with a strong preference for linear dinucleotides over cyclic dinucleotides. Although NrnA exhibited detectable cyclic dinucleotide hydrolytic activities in vitro, NrnA had negligible effects on their levels in the bacterial cell, even in the absence of the c-di-AMP phosphodiesterases PdeA and PgpH. The ΔnrnA mutant had a mammalian cell infection defect that was fully restored by Escherichia coli Orn. Together, our data indicate that L. monocytogenes NrnA is functionally orthologous to Orn, and its preferred physiological substrates are most likely linear dinucleotides. Furthermore, our findings revealed that, unlike some other c-di-AMP- and c-di-GMP-producing bacteria, L. monocytogenes does not employ their hydrolytic products to regulate their phosphodiesterases, at least at the pApA and pGpG levels in the ΔnrnA mutant. Finally, the ΔnrnA infection defect was overcome by constitutive activation of PrfA, the master virulence regulator, suggesting that accumulated linear dinucleotides inhibit the expression, stability, or function of PrfA-regulated virulence factors. IMPORTANCE Listeria monocytogenes produces both c-di-AMP and c-di-GMP and encodes specific phosphodiesterases that degrade them into pApA and pGpG, respectively, but the metabolism of these products has not been characterized in this bacterium. We found that L. monocytogenes NrnA degrades a broad range of nucleotides. Among the tested cyclic and linear substrates, it exhibits a strong biochemical and physiological preference for the linear dinucleotides pApA, pGpG, and pApG. Unlike in some other bacteria, these oligoribonucleotides do not appear to interfere with cyclic dinucleotide hydrolysis. The absence of NrnA is well tolerated by L. monocytogenes in broth cultures but impairs its ability to infect mammalian cells. These findings indicate a separation of cyclic dinucleotide signaling and oligoribonucleotide metabolism in L. monocytogenes.

Carnosine synthase deficiency is compatible with normal skeletal muscle and olfactory function but causes reduced olfactory sensitivity in aging mice.

Carnosine (ß-alanyl-l-histidine) and anserine (ß-alanyl-3-methyl-l-histidine) are abundant peptides in the nervous system and skeletal muscle of many vertebrates. Many in vitro and in vivo studies demonstrated that exogenously added carnosine can improve muscle contraction, has antioxidant activity, and can quench various reactive aldehydes. Some of these functions likely contribute to the proposed anti-aging activity of carnosine. However, the physiological role of carnosine and related histidine-containing dipeptides (HCDs) is not clear. In this study, we generated a mouse line deficient in carnosine synthase (Carns1). HCDs were undetectable in the primary olfactory system and skeletal muscle of Carns1-deficient mice. Skeletal muscle contraction in these mice, however, was unaltered, and there was no evidence for reduced pH-buffering capacity in the skeletal muscle. Olfactory tests did not reveal any deterioration in 8-month-old mice lacking carnosine. In contrast, aging (18-24-month-old) Carns1-deficient mice exhibited olfactory sensitivity impairments that correlated with an age-dependent reduction in the number of olfactory receptor neurons. Whereas we found no evidence for elevated levels of lipoxidation and glycation end products in the primary olfactory system, protein carbonylation was increased in the olfactory bulb of aged Carns1-deficient mice. Taken together, these results suggest that carnosine in the olfactory system is not essential for information processing in the olfactory signaling pathway but does have a role in the long-term protection of olfactory receptor neurons, possibly through its antioxidant activity.

Overview and Emerging Trends in the Treatment of Osteoradionecrosis.

OPINION STATEMENT: Osteoradionecrosis (ORN) of the mandible is a rare but devastating complication which occurs following radiation therapy for head and neck malignancies. Left untreated, ORN often results in pathologic fracture of the mandible leading to pain, trismus, difficulty eating, and overall poor quality of life. Historically, early intervention relied on hyperbaric oxygen and local debridement. Patients whose disease progressed despite therapy required segmental resection of the mandible with osseous free flap reconstruction, a highly invasive operation. Patients that presented with a moderate disease without pathologic fracture were often doomed to fail non-operative management, ultimately leading to disease progression and fracture. The traditional dichotomous treatment paradigm left a void of options for patients with moderate disease. The ideal intervention for this category of patients would provide renewed vascularity to the diseased tissue bed allowing for the osteogenesis and reestablishment of strong, load-bearing bone. The innovative technique termed the vascularized fascia lata "rescue flap" has proven to be an effective treatment for moderate ORN and will likely transform dated treatment algorithms.

Urban air PM modifies differently immune defense responses against bacterial and viral infections in vitro.

Epidemiological evidence has shown the association between exposure to ambient fine particulate matter (PM) and increased susceptibility to bacterial and viral respiratory infections. However, to date, the underlying mechanisms of immunomodulatory effects of PM remain unclear. Our objective was to explore how exposure to relatively low doses of urban air PM alters innate responses to bacterial and viral stimuli in vitro. We used secondary alveolar epithelial cell line along with monocyte-derived macrophages to replicate innate lung barrier in vitro. Co-cultured cells were first exposed for 24 h to PM2.5-1 (particle aerodynamic diameter between 1 and 2.5 µm) and subsequently for an additional 24 h to lipopolysaccharide (TLR4), polyinosinic-polycytidylic acid (TLR3), and synthetic single-stranded RNA oligoribonucleotides (TLR7/8) to mimic bacterial or viral stimulation. Toxicological endpoints included pro-inflammatory cytokines (IL-8, IL-6, and TNF-α), cellular metabolic activity, and cell cycle phase distribution. We show that cells exposed to PM2.5-1 produced higher levels of pro-inflammatory cytokines following stimulation with bacterial TLR4 ligand than cells exposed to PM2.5-1 or bacterial ligand alone. On the contrary, PM2.5-1 exposure reduced pro-inflammatory responses to viral ligands TLR3 and TLR7/8. Cell cycle analysis indicated that viral ligands induced cell cycle arrest at the G2-M phase. In PM-primed co-cultures, however, they failed to induce the G2-M phase arrest. Contrarily, bacterial stimulation caused a slight increase in cells in the sub-G1 phase but in PM2.5-1 primed co-cultures the effect of bacterial stimulation was masked by PM2.5-1. These findings indicate that PM2.5-1 may alter responses of immune defense differently against bacterial and viral infections. Further studies are required to explain the mechanism of immune modulation caused by PM in altering the susceptibility to respiratory infections.

Is the Risk to Develop Osteoradionecrosis of the Jaws Following IMRT for Head and Neck Cancer Related to Co-Factors?

Background and Objectives: Determine the contribution of coexisting factors to the risk to develop Osteoradionecrosis (ORN) of the jaws among patients who have received radiotherapy by intensity modulated radiation therapy (IMRT) for head and neck cancer (HNC) between 2013 and 2016, in a single medical center. Materials and Methods: The records of all patients treated with IMRT for HNC between 2013 and 2016 in The Davidoff Center for the treatment and Research of Cancer in Rabin Medical Center-Beilinson hospital, Petah-Tikva, Israel were screened. Patients who have received a minimum mean dose of 40 Gy to the oral cavity entered the research and their medical records were retrospectively reviewed. Collected background data included: age, gender, smoking, diabetes mellitus (DM), ASA score, mean and maximal radiation doses (Gy), and diseases characteristics including histological diagnosis, primary tumor site, and disease stage. Results: A total of 1232 patients were surveyed. Out of all screened patients, 93 received a minimum mean dose of 40 Gy to the oral cavity. Out of the 93 patients, 7 (7.52%) developed ORN (ORN+) and 86 did not develop ORN (ORN-). Tumor type in all seven patients in the ORN+ group was Squamous Cell Carcinoma (SCC). In three out of those seven patients (42.9%), the tumor was located in the mandible. Conclusions: within the limits of the relatively small cohort in the current study, we suggest that the development of ORN due to Radiation therapy (RT) with IMRT is related significantly only to the location of a tumor in the mandible. Other co-factors do not significantly increase the risk to develop ORN when RT is delivered via IMRT.

Rapidly Correcting Frameshift Mutations in the Mycobacterium tuberculosis orn Gene Produce Reversible Ethambutol Resistance and Small-Colony-Variant Morphology.

We have identified a previously unknown mechanism of reversible high-level ethambutol (EMB) resistance in Mycobacterium tuberculosis that is caused by a reversible frameshift mutation in the M. tuberculosisorn gene. A frameshift mutation in orn produces the small-colony-variant (SCV) phenotype, but this mutation does not change the MICs of any drug for wild-type M. tuberculosis However, the same orn mutation in a low-level EMB-resistant double embB-aftA mutant (MIC = 8 µg/ml) produces an SCV with an EMB MIC of 32 µg/ml. Reversible resistance is indistinguishable from a drug-persistent phenotype, because further culture of these orn-embB-aftA SCV mutants results in rapid reversion of the orn frameshifts, reestablishing the correct orn open reading frame, returning the culture to normal colony size, and reversing the EMB MIC back to that (8 µg/ml) of the parental strain. Transcriptomic analysis of orn-embB-aftA mutants compared to wild-type M. tuberculosis identified a 27-fold relative increase in the expression of embC, which is a cellular target for EMB. Expression of embC in orn-embB-aftA mutants was also increased 5-fold compared to that in the parental embB-aftA mutant, whereas large-colony orn frameshift revertants of the orn-embB-aftA mutant had levels of embC expression similar to that of the parental embB-aftA strain. Reversible frameshift mutants may contribute to a reversible form of microbiological drug resistance in human tuberculosis.

Fibroblast growth factor signaling instructs ensheathing glia wrapping of Drosophila olfactory glomeruli.

The formation of complex but highly organized neural circuits requires interactions between neurons and glia. During the assembly of the Drosophila olfactory circuit, 50 olfactory receptor neuron (ORN) classes and 50 projection neuron (PN) classes form synaptic connections in 50 glomerular compartments in the antennal lobe, each of which represents a discrete olfactory information-processing channel. Each compartment is separated from the adjacent compartments by membranous processes from ensheathing glia. Here we show that Thisbe, an FGF released from olfactory neurons, particularly from local interneurons, instructs ensheathing glia to wrap each glomerulus. The Heartless FGF receptor acts cell-autonomously in ensheathing glia to regulate process extension so as to insulate each neuropil compartment. Overexpressing Thisbe in ORNs or PNs causes overwrapping of the glomeruli their axons or dendrites target. Failure to establish the FGF-dependent glia structure disrupts precise ORN axon targeting and discrete glomerular formation.

Intraoperative peripheral nerve injury related to lithotomy positioning with steep Trendelenburg in patients undergoing robotic-assisted laparoscopic surgery - A systematic review.

AIMS: To examine the incidence of intraoperative peripheral nerve injury, symptoms, risk factors, functions, and quality of life in patients undergoing robotic-assisted laparoscopic surgery to lithotomy positioning with steep Trendelenburg. DESIGN: A systematic review. DATA SOURCES: The Cochrane Library catalogue, PubMed, EMBASE, CINHAL and SveMed + databases were searched from January 2000 - February 2019. REVIEW METHODS: Titles and abstracts were screened for inclusion. Full-text assessments of each paper were conducted by two reviewers. The quality of the included papers was assessed using the Mixed Methods Appraisal Tool. Descriptive statistics and thematic analysis were used to synthesize the data. RESULTS: Eleven quantitative studies were included with three themes: (a) incidence of intraoperative peripheral nerve injury; (b) upper extremity intraoperative peripheral nerve injury related to steep Trendelenburg positioning; and (c) lower extremity intraoperative peripheral nerve injury related to lithotomy positioning. The overall incidence of intraoperative peripheral nerve injury in robotic-assisted laparoscopic urologic, gynaecologic and colorectal surgery was 0.16%-10.0% and the symptoms appeared immediately after surgical procedures. Risk factors for intraoperative peripheral injury were prolonged operative time, high American Society of Anesthesiologists scores, comorbidities and high body mass index. CONCLUSION: Intraoperative peripheral nerve injuries are rare, but occasionally serious when related to lithotomy positioning with steep Trendelenburg. Operating room nurses have a responsibility both for positioning patients and for being familiar with the technological developments that will influence the preoperative handling of patients. IMPACT: This systematic review emphasizes the need for operating room nurses together with surgical team to have knowledge about mechanisms for injury, positioning, anatomy/physiology, and evaluation of risk factors to ensure that patients are not exposed for intraoperative peripheral nerve injuries. Increased robotic-assisted laparoscopic surgery necessitates further research examining the incidence of intraoperative peripheral nerve injury related to positioning and how these affect patients' function and the quality of life.