Tuberculosis of head and neck region, our experience at a tertiary care center in Gujarat.

BACKGROUND: Head and neck lesions of tuberculosis, though not uncommon are often difficult to diagnose and require a unique management protocol. These lesions are often misdiagnosed as bacterial infections, malignancies or other granulomatous diseases. Hence in our study we endeavor to gain a better understanding of the diagnostic and management protocols of tuberculosis in otorhinolaryngology. METHODS: We have performed an observational study at our institute, the patient's details were obtained from patient record forms and noted in a standard proforma. Results were calculated as percentage and Chi square analysis was performed. RESULTS: We found cervical tuberculous lymphadenitis to be the most common manifestation 76.97%, with a significant association with pulmonary tuberculosis. Neck swelling was the most common presenting complaint, 65.35%. 26-50 years of age was the most commonly involved age group. CONCLUSION: FNAC, PCR and histopathology are the modalities for bacteriological diagnosis for tuberculosis of Head and Neck. Anti-tuberculous therapy is uniformly found to be useful in all the patients, with surgical intervention used as and when required.

Nasal Septal Cartilage as Anterior Cap-Graft for Open Tracheoplasty in Cases for Laryngotracheal Stenosis: Our Initial Experience.

The aim of our study is to analyze the efficacy of nasal septal cartilage as cap-graft in laryngo-tracheoplasty in cases of Laryngotracheal stenosis. This was a prospective observational study carried out at a tertiary care hospital from March 2020 to March 2023. Total 8 patients who underwent laryngo-tracheoplasty using nasal septal cartilage as anterior Cap-graft were included in the study. Detailed history and clinical evaluation followed by diagnostic Flexible Fiber-optic Laryngoscopy and radiological investigations were done for all patients with post operative follow up for at least 1 year. Our study had maximum patients in age group of 11-30 years with male predominance, unknown compound ingestion being most common cause of intubation which was followed by tracheostomy. All patients had Cotton Mayer Grade III or IV subglottic stenosis. Out of 8 patients, 5 patients are decannulated, 1 patients still have T-tube in-situ whereas 2 patients didn't tolerate decannulation and required re-exploration. No donor site complication was seen during the study period. Nasal septal cartilage is a viable option for being used as anterior cap graft in laryngo-tracheoplasty. It can be a game changer, as can be done by E.N.T surgeon himself. No separate learning skills are required. It's cosmetically better with minimal complications; compared to life threatening complications like pneumothorax on using costal cartilage. Laryngeal framework is preserved as opposed to thyroid alar cartilage graft. Faster healing along with better postoperative donor site recovery are significant advantages.

Inhibition of group IVA cytosolic phospholipase A2 by thiazolyl ketones in vitro, ex vivo, and in vivo.

Group IVA cytosolic phospholipase A2 (GIVA cPLA2) is the rate-limiting provider of pro-inflammatory mediators in many tissues and is thus an attractive target for the development of novel anti-inflammatory agents. In this work, we present the synthesis of new thiazolyl ketones and the study of their activities in vitro, in cells, and in vivo. Within this series of compounds, methyl 2-(2-(4-octylphenoxy)acetyl)thiazole-4-carboxylate (GK470) was found to be the most potent inhibitor of GIVA cPLA2, exhibiting an XI(50) value of 0.011 mole fraction in a mixed micelle assay and an IC50 of 300 nM in a vesicle assay. In a cellular assay using SW982 fibroblast-like synoviocytes, it suppressed the release of arachidonic acid with an IC50 value of 0.6 µM. In a prophylactic collagen-induced arthritis model, it exhibited an anti-inflammatory effect comparable to the reference drug methotrexate, whereas in a therapeutic model, it showed results comparable to those of the reference drug Enbrel. In both models, it significantly reduced plasma PGE2 levels.

Modeling of eicosanoid fluxes reveals functional coupling between cyclooxygenases and terminal synthases.

Eicosanoids, including prostaglandins (PG) and leukotrienes, are lipid mediators derived from arachidonic acid. A quantitative and biochemical level understanding of eicosanoid metabolism would aid in understanding the mechanisms that govern inflammatory processes. Here, we present a combined experimental and computational approach to understanding the biochemical basis of eicosanoid metabolism in macrophages. Lipidomic and transcriptomic measurements and analyses reveal temporal and dynamic changes of the eicosanoid metabolic network in mouse bone marrow-derived macrophages (BMDM) upon stimulation of the Toll-like receptor 4 with Kdo2-Lipid A (KLA) and stimulation of the P2X7 purinergic receptor with adenosine 5'-triphosphate. Kinetic models were developed for the cyclooxygenase (COX) and lipoxygenase branches of arachidonic acid metabolism, and then the rate constants were estimated with a data set from ATP-stimulated BMDM, using a two-step matrix-based approach employing a constrained least-squares method followed by nonlinear optimization. The robustness of the model was validated through parametric sensitivity, uncertainty analysis, and predicting an independent dataset from KLA-primed ATP-stimulated BMDM by allowing the parameters to vary within the uncertainty range of the calculated parameters. We analyzed the functional coupling between COX isozymes and terminal enzymes by developing a PGH2-divided model. This provided evidence for the functional coupling between COX-2 and PGE2 synthase, between COX-1/COX-2 and PGD2 synthase, and also between COX-1 and thromboxane A2 synthase. Further, these functional couplings were experimentally validated using COX-1 and COX-2 selective inhibitors. The resulting fluxomics analysis demonstrates that the "multi-omics" systems biology approach can define the complex machinery of eicosanoid networks.

Novel staphylococcal glycosyltransferases SdgA and SdgB mediate immunogenicity and protection of virulence-associated cell wall proteins.

Infection of host tissues by Staphylococcus aureus and S. epidermidis requires an unusual family of staphylococcal adhesive proteins that contain long stretches of serine-aspartate dipeptide-repeats (SDR). The prototype member of this family is clumping factor A (ClfA), a key virulence factor that mediates adhesion to host tissues by binding to extracellular matrix proteins such as fibrinogen. However, the biological siginificance of the SDR-domain and its implication for pathogenesis remain poorly understood. Here, we identified two novel bacterial glycosyltransferases, SdgA and SdgB, which modify all SDR-proteins in these two bacterial species. Genetic and biochemical data demonstrated that these two glycosyltransferases directly bind and covalently link N-acetylglucosamine (GlcNAc) moieties to the SDR-domain in a step-wise manner, with SdgB appending the sugar residues proximal to the target Ser-Asp repeats, followed by additional modification by SdgA. GlcNAc-modification of SDR-proteins by SdgB creates an immunodominant epitope for highly opsonic human antibodies, which represent up to 1% of total human IgG. Deletion of these glycosyltransferases renders SDR-proteins vulnerable to proteolysis by human neutrophil-derived cathepsin G. Thus, SdgA and SdgB glycosylate staphylococcal SDR-proteins, which protects them against host proteolytic activity, and yet generates major eptopes for the human anti-staphylococcal antibody response, which may represent an ongoing competition between host and pathogen.

Targeted proteomics of the eicosanoid biosynthetic pathway completes an integrated genomics-proteomics-metabolomics picture of cellular metabolism.

Eicosanoids constitute a diverse class of bioactive lipid mediators that are produced from arachidonic acid and play critical roles in cell signaling and inflammatory aspects of numerous diseases. We have previously quantified eicosanoid metabolite production in RAW264.7 macrophage cells in response to Toll-like receptor 4 signaling and analyzed the levels of transcripts coding for the enzymes involved in the eicosanoid metabolite biosynthetic pathways. We now report the quantification of changes in protein levels under similar experimental conditions in RAW264.7 macrophages by multiple reaction monitoring mass spectrometry, an accurate targeted protein quantification method. The data complete the first fully integrated genomic, proteomic, and metabolomic analysis of the eicosanoid biochemical pathway.

Exit from dormancy in microbial organisms.

Bacteria can exist in metabolically inactive states that allow them to survive conditions that are not conducive for growth. Such dormant cells may sense when conditions have improved and re-initiate growth, lest they be outcompeted by their neighbours. Growing bacteria turn over and release large quantities of their cell walls into the environment. Drawing from recent work on the germination of Bacillus subtilis spores, we propose that many microorganisms exit dormancy in response to cell wall muropeptides.

Induction and regulation of a secreted peptidoglycan hydrolase by a membrane Ser/Thr kinase that detects muropeptides.

Here, we report that the model Gram-positive organism, Bacillus subtilis, expresses and secretes a muralytic enzyme, YocH, in response to cell wall-derived muropeptides derived from growing cells but not lysed cells. This induction is dependent on PrkC, a membrane Ser/Thr kinase that binds to peptidoglycan and that belongs to a broadly conserved family including the essential PknB kinase of M. tuberculosis. YocH stimulates its own expression in a PrkC-dependent manner demonstrating the presence of an autoregulatory loop during growth. Cells lacking YocH display a survival defect in stationary phase but enzymes secreted by other cells in the culture rescue this defect. The essential translation factor EF-G is an in vivo substrate of PrkC and this phosphorylation occurs in response to muropeptides. Therefore, we hypothesize that YocH is used by the bacterium to digest peptidoglycan released by other bacteria in the milieu and that the presence of these fragments is detected by a membrane kinase that modifies a key regulator of translation as well as to stimulate its own expression.

Kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen 1 mimics Epstein-Barr virus EBNA1 immune evasion through central repeat domain effects on protein processing.

Kaposi's sarcoma-associated herpesvirus (KSHV/human herpesvirus 8 [HHV8]) and Epstein-Barr virus (EBV/HHV4) are distantly related gammaherpesviruses causing tumors in humans. KSHV latency-associated nuclear antigen 1 (LANA1) is functionally similar to the EBV nuclear antigen-1 (EBNA1) protein expressed during viral latency, although they have no amino acid similarities. EBNA1 escapes cytotoxic lymphocyte (CTL) antigen processing by inhibiting its own proteosomal degradation and retarding its own synthesis to reduce defective ribosomal product processing. We show here that the LANA1 QED-rich central repeat (CR) region, particularly the CR2CR3 subdomain, also retards LANA1 synthesis and markedly enhances LANA1 stability in vitro and in vivo. LANA1 isoforms have half-lives greater than 24 h, and fusion of the LANA1 CR2CR3 domain to a destabilized heterologous protein markedly decreases protein turnover. Unlike EBNA1, the LANA1 CR2CR3 subdomain retards translation regardless of whether it is fused to the 5' or 3' end of a heterologous gene construct. Manipulation of sequence order, orientation, and composition of the CR2 and CR3 subdomains suggests that specific peptide sequences rather than RNA structures are responsible for synthesis retardation. Although mechanistic differences exist between LANA1 and EBNA1, the primary structures of both proteins have evolved to minimize provoking CTL immune responses. Simple strategies to eliminate these viral inhibitory regions may markedly improve vaccine effectiveness by maximizing CTL responses.