Publications by authors named "Papazian N"

Malignant plasma cells in multiple myeloma patients reside in the bone marrow and continuously interact with local immune cells. Progression and therapy response are influenced by this immune environment, highlighting the need for a detailed understanding of endogenous immune responses to malignant plasma cells. Here we used the 5TGM1 murine transfer model of multiple myeloma to dissect early immune responses to myeloma cells.

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Human bone marrow permanently harbors high numbers of neutrophils, and a tumor-supportive bias of these cells could significantly impact bone marrow-confined malignancies. In individuals with multiple myeloma, the bone marrow is characterized by inflammatory stromal cells with the potential to influence neutrophils. We investigated myeloma-associated alterations in human marrow neutrophils and the impact of stromal inflammation on neutrophil function.

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Progression and persistence of malignancies are influenced by the local tumor microenvironment, and future eradication of currently incurable tumors will, in part, hinge on our understanding of malignant cell biology in the context of their nourishing surroundings. Here, we generated paired single-cell transcriptomic datasets of tumor cells and the bone marrow immune and stromal microenvironment in multiple myeloma. These analyses identified myeloma-specific inflammatory mesenchymal stromal cells, which spatially colocalized with tumor cells and immune cells and transcribed genes involved in tumor survival and immune modulation.

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Innate lymphoid cells (ILCs) are enriched in mucosae and have been described as tissue-resident. Interestingly, ILCs are also present within lymph nodes (LNs), in the interfollicular regions, the destination for lymph-migratory cells. We have previously shown that LN ILCs are supplemented by peripheral tissue-derived ILCs.

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Upon viral infection, stressed or damaged cells can release alarmins like IL-33 that act as endogenous danger signals alerting innate and adaptive immune cells. IL-33 coming from nonhematopoietic cells has been identified as important factor triggering the expansion of antiviral CD8 T cells. In LN the critical cellular source of IL-33 is unknown, as is its potential cell-intrinsic function as a chromatin-associated factor.

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Tissue repair requires temporal control of progenitor cell proliferation and differentiation to replenish damaged cells. In response to acute insult, group 3 innate lymphoid cells (ILC3s) regulate intestinal stem cell maintenance and subsequent tissue repair. ILC3-derived IL-22 is important for stem cell protection, but the mechanisms of ILC3-driven tissue regeneration remain incompletely defined.

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Under homeostatic conditions, dendritic cells (DCs) continuously patrol the intestinal lamina propria. Upon antigen encounter, DCs initiate C-C motif chemokine receptor 7 (CCR7) expression and migrate into lymph nodes to direct T cell activation and differentiation. The mechanistic underpinnings of DC migration from the tissues to lymph nodes have been largely elucidated, contributing greatly to our understanding of DC functionality and intestinal immunity.

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Background: DeQuervain tenosynovitis, refractory to medical conservative treatment, has been traditionally treated by a simple division of the pulley, a procedure associated with several complications. Many authors attempted to prevent these complications by describing techniques of pulley reconstruction after its release necessitating suturing the different flaps and subsequently promoting extensor tendons adhesions. The authors present an alternative procedure for the first extensor compartment pulley decompression: "Omegaplasty".

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IL-7 is essential for the development and homeostasis of T and B lymphocytes and is critical for neonatal lymph node organogenesis because mice lack normal lymph nodes. Whether IL-7 is a continued requirement for normal lymph node structure and function is unknown. To address this, we ablated IL-7 function in normal adult hosts.

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A substantial number of human and mouse group 3 innate lymphoid cells (ILC3s) reside in secondary lymphoid organs, yet the phenotype and function of these ILC3s is incompletely understood. Here, we employed an unbiased cross-tissue transcriptomic approach to compare human ILC3s from non-inflamed lymph nodes and spleen to their phenotypic counterparts in inflamed tonsils and from circulation. These analyses revealed that, in the absence of inflammation, lymphoid organ-residing ILC3s lack transcription of cytokines associated with classical ILC3 functions.

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Despite a considerable decrease in their incidence worldwide, burn injuries remain one of the commonest forms of trauma and account for a weighty proportion of trauma cases in health-care emergencies around the globe. Although the latest data reveal a substantial decline in burn-related mortality and hospital admissions in the US over the past three decades, severe thermal injuries continue to trigger devastating morbidity and significant mortality while their management remains a dynamic challenge for the entire medical and paramedical community. Concrete evidence continues to be established regarding burn-associated pathophysiologic responses, and their destructive sequelae and deleterious effects in survivors at cellular, systemic as well as socio-economic level.

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Unlabelled: The inframammary fold (IMF) is the most critical visual landmark that affects final aesthetic outcome of augmentation mammoplasty and even post-mastectomy alloplastic breast reconstruction. Unfortunately, structural integrity of this landmark is greatly overlooked and very often neglected. Excessive undermining of the lower breast pole with aggressive disruption/lowering and subsequent poor reconstitution of the IMF scaffold combined with imbalanced implant-tissue dynamics may result in downward implant displacement with creep bottoming and upward tilt of the nipples.

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Interleukin 22 (IL-22) expression is associated with increased joint destruction and disease progression in rheumatoid arthritis (RA). Although IL-22 is considered a pro-inflammatory cytokine, its mechanism of action in RA remains incompletely understood. Here, we used the collagen-induced arthritis model in IL-22 deficient (IL-22(-/-) ) mice to study the role of IL-22 in RA.

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Background: The lateral arm flap remains an underused flap, especially as a free flap. In this article, the authors describe the perforator anatomy to optimize flap design and harvest.

Methods: Perforator locations were mapped in 12 cadavers (24 arms), and a retrospective review was conducted of 51 patients undergoing lateral arm flap surgery.

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Pharyngo-esophageal and tracheostomal defects pose a challenge in head and neck reconstruction whenever microanastomosis is extremely difficult in hostile neck that is previously dissected and irradiated. The deltopectoral (DP) flap was initially described as a pedicled flap for such reconstruction with acceptable postoperative results. A major drawback is still that the DP flap is based on 3 perforator vessels leading to a decreased arc of rotation.

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Unlabelled: Acceptable scar positioning on the anterior male chest is very limited. In Gynecomastia surgery, an obvious areolar incision is the most sensitive indicator of a previous operation; a less apparent scar is indispensable for the patient's psychological satisfaction. Whenever only areolar diameter reduction is required, the circumareolar incision must be performed in a position leaving the least conspicuous scar.

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Background: The art of reconstructive microsurgery is still progressing after Carrel's original description of "vascular repair" in 1902. Reports of the successful repair of vessels smaller than 1 mm in diameter are currently commonplace. However, the technique of microvascular anastomosis to connect vessels with large diameter discrepancy, greater than 1 mm, has not yet been perfected.

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Article Synopsis
  • Disruption of the intestinal barrier can lead to inflammation, as the body struggles to repair itself after damage, particularly following chemotherapy.
  • Intestinal stem cells are crucial for maintaining the epithelial layer, but their high turnover makes them vulnerable to cancer treatments.
  • Type 3 innate lymphoid cells (ILC3s) play a vital role in helping these stem cells recover and activate after damage, and without them, there's more tissue damage and impaired recovery of the intestinal lining.
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Adaptive immunity critically depends on the functional compartmentalization of secondary lymphoid organs. Mesenchymal stromal cells create and maintain specialized niches that support survival, activation, and expansion of T and B cells, and integrated analysis of lymphocytes and their niche has been instrumental in understanding adaptive immunity. Lymphoid organs are also home to type 3 innate lymphoid cells (ILC3), innate effector cells essential for barrier immunity.

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Tying sutures is an integral aspect of any surgery and reliable instruments are essential for hassle-free procedures including craniofacial surgeries. Knot pushers have been widely known for their application in various laparoscopic, arthroscopic, and anal surgeries. The literature reveals numerous articles pertaining to knot pushers, as well as improvements on existing designs.

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The minimal access cranial suspension lift, a short-scar facelift, has been described to correct sagging and laxity of the lower and middle third of the face. It does not, however, fully address the neck or the lateral periorbital area frequently needing rejuvenation in most patients. Another shortcoming of the minimal access cranial suspension lift technique is visible scarring anterior to the temporal hairline that usually occurs despite the suggested surgical maneuvers consisting in zigzag beveled incisions.

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Tertiary lymphoid structures (TLSs) in chronic inflammation, including rheumatoid arthritis (RA) synovial tissue (ST), often contain high endothelial venules and follicular dendritic cells (FDCs). Endothelial cell (EC)-specific lymphotoxin β (LTβ) receptor signaling is critical for the formation of lymph nodes and high endothelial venules. FDCs arise from perivascular platelet-derived growth factor receptor β(+) precursor cells (preFDCs) that require specific group 3 innate lymphoid cells (ILC3s) and LTβ for their expansion.

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Clusters of cells attached to the endothelium of the main embryonic arteries were first observed a century ago. Present in most vertebrate species, such clusters, or intraaortic hematopoietic clusters (IAHCs), derive from specialized hemogenic endothelial cells and contain the first few hematopoietic stem cells (HSCs) generated during embryonic development. However, some discrepancies remained concerning the spatio-temporal appearance and the numbers of IAHCs and HSCs.

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When using the inframammary access incision for breast augmentation, careful planning is critical to allow the surgeon to set the inframammary fold (IMF) at the most optimal position, minimize scar visibility, and mitigate the main disadvantage of this approach. Current popular evaluation systems for breast augmentation include the High Five and Randquist systems and they base their calculations on inconsistent variables like skin stretch measurements. We propose a simple method that is not dependent on skin stretch measurements to properly determine implant size, profile, and position of the inframammary fold.

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