Venous Sinusoids Research Articles

Histogenesis of Human Fetal Spleen

Abstract Background and Aims: Spleen is the largest secondary lymphatic organ. It acts as a graveyard for RBCs, is essential for immune responses, performs lymphopoiesis in adults and haemopoiesis in fetuses. The present study was conducted to assess the histogenesis of spleen in human fetuses in view of existing literature. Material and Methods: The study was carried out on 34 formalin preserved human fetuses procured from Dr Sushila Tiwari Government Hospital, Haldwani with due clearance from ethical committee. The 6 pm sections of the spleen were stained with Haematoxylin and Eosin and observed under light microscope. Results: At 14 tol5 weeks, spleen had extensive sinusoids filled with RBCs and few lymphocytes. At 16-18 weeks, trabecular arteries were noticed more towards centre along with extensive haemopoietic cells in the venous sinusoids. By 20th week lymphocytic aggregation had started around arterioles. By 24 weeks periarteriolar lymphatic sheath was clearly observed. At term (37-40 weeks), classical primary lymphoid follicle was present but germinal centers were not observed. Conclusion: During earlier differentiation, spleen symbolizes the function of haemopoietic activities and gradually during subsequent gestation; it establishes its identity as a principle lymphoid tissue.

Myeloid Dendritic Cells Contribute to Hematopoietic Homeostasis

Dendritic cells (DCs) are antigen-presenting cells that are distributed throughout the body, and their main function is thought to be immune-surveillance. There is considerable phenotypic and functional heterogeneity of dendritic cells that tracks, in part, with their tissue localization. Myeloid dendritic cells (mDC), also known as conventional dendritic cells, are DCs with a myeloid origin. A previous study showed that perivascular mDCs in the bone marrow provide signals that regulate the survival of mature B cells (Sapoznikov et al., Nat Immunol, 2008). Using Cx3cr1gfp/+mice, we show that mDCs, defined as CX3CR1-GFP-bright, MHCII-bright cells, represent 0.2 ± 0.08% of bone marrow cells. They are localized to both venous sinusoids and arterioles in the bone marrow, placing them in the perivascular stem niche, along with CXCL12-abundant reticular (CAR) cells and Nestin-GFP+ cells. To assess the contribution of mDCs to the regulation of hematopoiesis, we used two independent mouse models to ablate mDCs: CD11cDTR and Zbtb46DTR mice. We previously reported that ablation of mDCs induces modest hematopoietic stem/progenitor (HSPC) mobilization. We show that mDC ablation also suppresses osteoblast function, with expression of osteocalcin mRNA (a marker of mature osteoblasts) decreasing 3.5-fold after mDC ablation (from 18.7 ± 9.9 to 5.3 ± 3.0; P < 0.05).To our surprise, mDC ablation (in both models) was associated with a significant loss of bone marrow macrophages. Prior studies have shown that macrophage ablation results in a loss of mature osteoblasts and modest HPSC mobilization. Thus, it is not clear whether mDCs have an independent effect on HSPC trafficking and osteoblast function. To address this issue, we first asked whether the macrophage loss after mDC ablation was mediated in a non-cell autonomous fashion. Mixed bone marrow chimeras were established containing both Zbtb46DTR and wild-type hematopoietic cells. Upon treatment with diphtheria toxin, we observed depletion of Zbtb46DTR but not wild-type mDCs (as expected). In contrast, a similar decrease in both Zbtb46DTR and wild-type macrophages was observed. These data show that the decrease in macrophages is an indirect consequence of mDC ablation and suggest that mDCs generate signals that contribute to macrophage retention and/or survival in the bone marrow. To further address the role of macrophages in this phenotype, we generated mice expressing Zbtb46-DTR alone, CD169-DTR alone (previously shown to ablate macrophages), or mice carrying both Zbtb46-DTR and CD169-DTR. As reported previously, ablation of macrophages induces a modest mobilization of Kit+ Sca1+ lineage- (KSL) cells to the spleen (7.1 ± 3.2 x104 versus 3.0 ± 1.2 x104 for PBS treated mice; P =0.06). Ablation of mDCs also induces modest mobilization (9.1 ± 2.5 x104 versus 5.8 ± 3.5 x104 for PBS treated mice; P < 0.05). Preliminary analysis of double mutant mice (n = 4) suggest an additive effect of combined mDC and macrophage ablation on HSPC mobilization with 25.9 ± 18.4 x104 KSL cells per spleen (P < 0.05 compared with macrophage alone ablation). Likewise, preliminary analysis suggests that the magnitude of osteoblast suppression (as measured by osteocalcin expression) is greater in double mutant mice. Collectively, these data suggest that bone marrow mDCs, in addition to a possible role in immune surveillance, contribute to blood homeostasis through multiple mechanisms. Specifically, mDCs appear to generate signals that are required for macrophage retention and/or survival in the bone marrow. mDCs also regulate HSPC trafficking and osteoblast function through a macrophage independent mechanism. Studies are underway to identify signals generated by mDCs that mediate these biological responses. DisclosuresNo relevant conflicts of interest to declare.

Unexplained recurrent hematuria and clot retention following transurethral resection of the prostate

Severe hemorrhage following a prostatectomy is a rare and serious complication. A 60-year-old male with recurrent hematuria and clot retention following transurethral resection of the prostate (TURP) which led to anemia presented at our department and was treated with repeated clot evacuation and fulguration and lastly re-resection and fulguration succeed to stop bleeding. At 18 months follow-up, the patient had recovered well. We concluded that re-resection and fulguration on fresh tissue without opening the venous sinusoids should be considered as one of the effective treatment of choice in recurrent hemorrhage following TURP.

Characterization and Isolation of Splenic Littoral Cells, a Possible Cellular Niche for Extramedullary Hematopoiesis in Myelofibrosis

Splenic littoral cells (LC) line the venous sinusoids of the human spleen and have been thought to act as blood cells filters. Little is known about SLCs beyond their preliminary characterization using immunochemistry and electron microscopy by others. Since SLCs comprise a significant portion of spleen, we hypothesized that SLC might be an important component of the splenic microenvironment that contributes to the development of extramedullary hematopoiesis in myelofibrosis (MF) patients.To further phenotypically characterize viable SLCs, surgically removed fresh spleens were treated with collagenase B and the hematopoietic cells were depleted using anti-CD45 micro-beads. The enriched CD45- cells were then stained and analyzed on a FACS analyzer. The SLCs were i, CD3-, CD45-, CD34-, CD8a+, CD31+ (Figure 1), ii, CD206+, CD21-, CD14-, FHOD1+, SIRP1a+, a phenotype identical to that previously reported based on IHC. SLCs and SECs were then identified by IHC in the red pulp of healthy individuals and MF patients using anti- CD8a and CD34 antibodies. SLCs were much more abundant than ECs in normal spleens. MF SLCs were however, much less condensed due to the expansion of hematopoietic cells than normal SLCs and the sinusoids encircled by SLCs were more elongated and had a more irregular shape as compared to normal spleen (Figure 2).To isolate the viable SLC and EC, fresh or cryopreserved spleen single cell suspensions were prepared as above and were FACS sorted for CD3-, CD45-, CD34-, CD8a+, CD31+ SLCs and CD3-, CD45-, CD34+, CD8a-, CD31+ SECs. The SSC/FSC profiles revealed two cell populations which could be distinguished by size and complexity, SLC being bigger and less uniform in size and shape. The CD31 signal intensity was greater in SEC than in SLC.The gene expression profiles of FACS sorted SLC, SEC and mononuclear cells (MNCs) were analyzed using human genome U133 Plus 2.0 arrays. DAVID Functional Annotation Clustering was applied to identify enriched gene clusters in selected lists. MNCs were significantly different from both SLC and EC, which expressed several clusters of genes involved in cell morphology, adhesion, and blood vessel formation. This indicated that SLCs were not closely related to myeloid cells but share features with SEC. SLC could however be differentiated from SEC by expression of genes involved in chromatin modification and regulation of RAS protein signaling, as well as intravesicle transportation genes, which may be related to their assumed capacity for phagocytosis. In addition SLC expressed many cytokines and adhesion molecules known to support hematopoiesis. Transcripts for various cytokines expressed by SEC and SLC were, however, distinct suggesting that they might serve as niches for different subpopulations of HSC/HPC. Preliminary microarray analysis of SLCs from an MF patient was also performed. Genes associated with apoptosis, intracellular lumens were upregulated as well as a cluster of genes in the cancer pathway. Cell cycle genes, genes of transcription regulation, and proteolysis were down-regulated in MF SLCs.Sorted SLC were also cultured in EC medium (ECM). The cultured SLCs were able to be repeatedly passaged. These cells were wide and spindle shaped. At a lower density, the cells tended to connect and organize into rings with a hollow space in the middle which resembled a splenic sinusoid. Immunostaining for CD8a and FHOD1 were conducted on these cultured cells, revealing that they continued to express these two markers. Interestingly, the expression of FHOD1, a stress fiber inducing protein was strongly polarized.To determine the relationship between SLC and the MF malignant clone SLCs from MF patients were isolated and assayed for JAK2V617F using allele specific NESTED PCR. Samples from three MF patients, were analyzed and no JAK2V617F was detected.In conclusion, we have isolated, cultured and characterized SLCs from normal and MF spleens for the first time. This will allow for further analysis of their function in normal individuals and individuals with blood diseases. [Display omitted] [Display omitted] DisclosuresSalama:Promedior: Consultancy.

Impact-driven, pulmonary emboli of osseous fat in exercise-induced bronchospasm

Exercise induced bronchospasm (EIB) affects approximately 10% of normal individuals with higher prevalence rates among children, obese adults, and competitive athletes. Although hyperpnea with dry air is the best known cause, the problem is multifactorial with atopy, asthma and chlorine all playing established roles. To date, no clear mechanism has connected musculoskeletal loading with the ensuing pulmonary compromise.This paper reviews evidence that impact-driven pulses in subchondral bone pressure may push osseous fat cells into the local venous sinusoids. The resultant showers of microemboli must then travel to the lung where lysis of membrane phospholipids leads to leukotriene formation with resultant inflammation and bronchial hypersensitivity. Concurrently, the same emboli deliver triglyceride fuels for further physical activity.Thus, pulmonary microemboli derived from osseous fat may resolve the seeming paradox of athletic excellence in persons afflicted with exercise-induced bronchospasm.

Paediatric vascular access

### Key points Obtaining reliable vascular access in small children is frequently made challenging by anatomical factors—in particular, small, mobile veins and an excess of subcutaneous fat which make visualization and palpation of veins difficult. Paediatric patients are often less co-operative, and the potential for psychological trauma, especially with repeated procedures in the conscious patient, further complicates matters. Short-term vascular access is frequently required in hospitalized children for the delivery of i.v. fluids, medication, and blood product administration. Longer-term vascular access devices are required for repeated medication delivery (e.g. enzyme replacement therapy in inherited metabolic diseases), chemotherapy, immunotherapy, total parenteral nutrition, and extracorporeal procedures such as plasmapheresis and haemodialysis. In addition, vascular access devices may be needed for repeated blood sampling and invasive haemodynamic monitoring. The choice of vascular access device depends upon the condition and preference of the patient or parent/guardian, the likely duration and frequency of treatment, and the properties of the infusate. Infusates with vesicant properties (drugs with the potential to cause blistering with tissue injury, e.g. calcium solutions and amphotericin B), hypertonic solutions, and those with pH 9 will necessitate central venous access. Vasopressors and inotropes are preferentially administered centrally as they require reliable access and extravasation may cause tissue necrosis. It is important to try to predict future needs for vascular access as poor prospective management …

Perivascular deletion of murine Rac reverses the ratio of marrow arterioles and sinusoid vessels and alters hematopoiesis in vivo

AbstractHematopoietic stem cells (HSCs) are localized within specialized microenvironments throughout the BM. Nestin-expressing (Nestin+) mesenchymal stromal cells (MSCs) are important in the perivascular space. Rac is critical for MSC cell shape in vitro, whereas its function in MSCs in vivo remains poorly characterized. We hypothesized that deletion of Rac in the Nestin+ cells would perturb the perivascular space, altering HSC localization and hematopoiesis. Nestin-Cre–directed excision of Rac1 in Rac3−/− mice reduces Nestin+ cells in the marrow. We observed a 2.7-fold decrease in homing of labeled wild-type hematopoietic cells into Rac1Δ/ΔRac3−/− mice compared with control mice. Rac1Δ/ΔRac3−/− mice demonstrated a marked decrease in arterioles and an increase in the number and volume of venous sinusoids in the marrow that was associated with a reduction in the numbers of immunophenotypically and functionally-defined long-term HSCs in the marrow, a decrease in colony-forming cells and a reduction in circulating progenitors. Rac-deleted animals demonstrated a significant increase in trabecular bone. These data demonstrate that Rac GTPases play an important role in the integrity of perivascular space. Increased trabecular bone and sinusoidal space and decreased arteriolar volume in this model were associated with decreased HSC, underscoring the complexity of regulation of hematopoiesis in the perivascular space.

Morphogenesis of the liver fibrosis development and progression in chronic hepatitis C

Aim. The paper contains the results of pathohistological integrated computer-morphometric and immunohistochemical liver bioptates research of the patients with chronic viral hepatitis C to upgrade the most significant microscopic features of the liver fibrosis development and progression. Methods and results. As a result of the research, histological activity index of chronic viral hepatitis C didn’t correlate in all the patients with liver fibrosis, found in histological preparations colored by Masson’s trichrome Stain or van Gieson’s Stain. Conclusion. It has been stated that the prognostic signs of probability of liver fibrosis development in patients with chronic viral hepatitis C are hyperplasia of the activated positive A-SMA Ito cells in the liver perisinusoidal spaces and segmental collagenization of the intralobular venous sinusoids walls, availability of A-SMA positive fibroblasts in immunocellular «piecemeal necrosis» and in portal paths.

Should otolaryngologists pay more attention to nasal swell bodies?

Should otolaryngologists pay more attention to nasal swell bodies?

Ultrastructural effects of lead acetate on the spleen of rats

In this experiment, the ultrastructural effects of orally administered lead acetate on rat (Rattus rattus) spleen were studied. Rats weighing approximately 200-250 g were used in this experiment. They were divided into five groups, each one including five rats. Group I served as the normal control group while the others served as the experimental groups. The rats were exposed to oral administrations of lead acetate of 2.5 mg dissolved in 1 mL of drinking water per day. The administration lasted 96, 144, 336, and 432 h. The animals were anesthetized using chloroform inhalation and the peritoneum was stripped open and the spleen was removed and prepared for histological observation using a staining technique. Hypocellular white pulp, enlargement of venous sinusoids, clustering of heterochromatin in nucleus, vacuolation in the cytoplasm, swelling of mitochondria, and the distortion of rough endoplasmic reticulum cisterns were observed upon electron microscopic examination of the spleen tissue cells. These cytopathologic alterations indicate that lead acetate has some drastic toxicological effects on cellular structures.

Nasal septal turbinate: cadaveric study.

Despite the importance of its location, the functional behavior of the nasal septal turbinate (NST) is still not completely understood. Basic histological knowledge is still lacking. The aim of this study was to describe the histological features of the NST and to compare its morphometric features to those of the adjacent nasal septum and the inferior and middle turbinates. The study included 50 fresh cadavers. Excisional biopsy specimens of the NST with adjacent posterior septum were collected. In addition, mucosal and submucosal biopsy specimens were taken of the inferior and middle turbinates. Morphometric analysis was performed on five different tissue types: glandular elements, connective tissue stroma, arterial structures, and capillary or venous sinusoids. The mean proportion of venous sinusoids was statistically lower in the nasal septum and NST than in the inferior and middle turbinate. The mean proportion of glandular tissues was higher in the NST than in other regions of the nasal cavity. The mean proportion of arterial tissue was lower in the nasal septum and the NST. Significantly fewer capillary elements were found in the inferior and middle turbinates than in the nasal septum and NST. The mean proportion of connective tissues was lower in the NST than in other regions of the nasal cavity. The similar histopathological cell distribution in the middle and inferior turbinate supported a function as an erectile organ, but the findings for the NST pointed to different functional properties of this region.

High-Intensity Focused Ultrasound Leads to Histopathologic Changes of the Inferior Turbinate Mucosa with Allergic Inflammation

This study was aimed at understanding the histopathologic changes that occur in the nasal mucosa of patients with perennial allergic rhinitis after high-intensity focused ultrasound (HIFU) treatment. Biopsy specimens of the inferior turbinate mucosa were taken from 11 PAR patients before, immediately after and 1 y after HIFU treatment. Morphometric analysis revealed that the density of eosinophils and other inflammatory cells increased immediately after treatment and then were decreased significantly 1 y post-treatment. Submucosal glands were swollen and venous sinusoids were dilated, but there was no statistically significant change in their density, immediately after treatment. However, both glands and venous sinusoids significantly decreased in number 1 y after HIFU treatment. The ciliated epithelium or basement membrane of the nasal mucosa was well preserved at all stages. In conclusion, HIFU is a tolerable and effective treatment to reduce inflammation of the inferior turbinate mucosa in patients with perennial allergic rhinitis.

ASYMMETRIC NASAL MUCOSAL THICKENING IN HEALTHY DOGS CONSISTENT WITH THE NASAL CYCLE AS DEMONSTRATED BY MRI AND CT

The nasal cycle is a physiological phenomenon that causes regular cyclical congestion and decongestion of the venous sinusoids lining the nasal mucosa. The purpose of this prospective study was to describe magnetic resonance imaging (MRI) and computed tomographic (CT) features of the normal nasal cycle in a group of dogs. Five dogs were recruited that met the following criteria: 8 to 15 months old, nonbrachiocephalic breed, no clinical signs or history of nasal disease, and undergoing anesthesia for problems unrelated to the nasal cavity. Nasal MRI (n = 5) and CT scans (pre- and postcontrast, n = 5) were acquired. Images were evaluated subjectively by two board-certified radiologists and objectively by a diagnostic imaging intern using regions of interest placed on each side of the nasal cavity. Findings were compared using Cohen's kappa coefficient and Students t-test on log-transformed data. All dogs showed diffuse unilateral mucosal thickening of the rostral part of the nasal cavity in both MRI and CT studies. This mucosal thickening shifted sides between examinations in three dogs. Changes appeared most marked on T2-weighted scans. No asymmetric mucosal changes were seen in the mucosa of the ethmoturbinates, vomer-nasal septum, hard palate or the frontal sinuses in any patient on MRI or CT. Computed tomographic contrast enhancement of the thickened mucosa was not statistically significant (P-value < 0.08). In conclusion, the normal nasal cycle may cause asymmetrical mucosal changes in the rostral part of the nasal cavity that mimic MRI and CT characteristics previously reported for inflammatory disease in dogs.

Histological Evaluation of the Nasal Swell Body in Allergic Patients

Introduction The nasal swell body (NSB), also called the nasal septal swell body or septal turbinate, is the thickest and widest region of the nasal septum. The NSB is located at the level of the internal nasal valve, and the anteriosuperior portion of the nasal septum is composed of cartilage, bone and its overlying mucoperichondrium (1). The presence and importance of the NSB has not been studied clinically and its function is not clear. High nasal septal deviations may even be misdiagnosed due to hypertrophy of this region. The NSB may experience nasal obstruction even following minimal changes in mucosal thickness. Computed tomography (CT) and magnetic resonance imaging (MRI) evaluation of the NSB showed vasoactive expansile properties but not as much as in the inferior turbinate (2, 3). Histological evaluation of the NSB revealed the presence of seromucinous glands, venous sinusoids and vascular structures (1).

Evaluation of fluorescence in situ hybridization for the detection of bacteria in feline inflammatory liver disease.

The etiopathogenesis of feline inflammatory liver disease (ILD) is unclear. Therefore, we sought to determine the presence and distribution of bacteria within the livers of cats with ILD using eubacterial fluorescence in situ hybridization (FISH). Histopathology from 39 cats with ILD and 19 with histologically normal livers (C) were classified using World Small Animal Veterinary Association guidelines. Hepatic sections were examined by 16 and 23S ribosomal RNA FISH. Antibodies against cytokeratins and factor VIIIa were used to distinguish bile ducts and vascular structures. Histopathologic findings included non-specific reactive hepatitis (12), neutrophilic cholangitis (NC; 12), lymphocytic cholangitis (seven), cholestasis/obstruction (three), probable lymphoma (three) and acute hepatitis (two). Bacteria were observed in 21/39 ILD and 3/19 C (P = 0.0054). In 8/39 ILD and 2/19 C bacteria were restricted to the outer liver capsule (P = 0.29) and may represent contaminants. The prevalence of intrahepatic bacteria was higher (P = 0.008) in ILD (13/31) than C (1/17). Bacteria in ILD were more frequently (P <0.0001) localized to portal vessels, venous sinusoids and parenchyma (12/13) than bile duct (1/13). Bacterial colonization was highest in Escherichia coli-positive NC cats. Concurrent non-hepatic disease, predominantly pancreatic and intestinal (8/10 cats biopsied), was present in all 13 cats with intrahepatic bacteria. Bacterial culture was positive (predominantly E coli and Enterococcus species) in 11/23 (48%) samples, and concurred with FISH in 15/23 cases. The presence of intrahepatic bacteria in 13/31 (41%) cats with ILD suggests a role in etiopathogenesis. The distribution of bacteria within the liver supports the possibility of colonization via either enteric translocation or hematogenous seeding.

Novel Spatiotemporal Glycome Changes in the Murine Placenta During Placentation Based on BS‐I Lectin Binding Patterns

Although spatiotemporal changes of the glycome (full set of glycans, otherwise known as saccharides or carbohydrates) during placenta formation (placentation) are functionally and clinically important, they are poorly defined. Here, we elucidated novel aspects of the glycome during mouse placentation, from embryonic day 6.5 (E6.5) to E12.5, by investigating the largely unexplored binding distribution of lectin I from Bandeiraea simplicifolia (BS-I lectin), a glycan-binding protein that recognizes the DGalNAc and DGal glycans found at the terminal ends of specific oligosaccharides attached to lipids or proteins. We show that BS-I lectin binding marks all trophoblast cells during early placentation (E7.5 and E8.5 stages), continues in labyrinthine and junctional zone trophoblast but is lost from parietal trophoblast giant cells by E10.5/E11.5 (definitive placenta stage) and is lost from all trophoblast types, but marks the fetal capillary endothelium of the labyrinth, by E12.5. In the decidua basalis (the maternal part of the placenta), BS-I lectin positivity mainly marks the decidual stroma cells of the venous sinusoid area (E7.5 and E8.5 stages) and the entire decidua basalis by E10.5, as well as the osteopontin-positive subset of uterine natural killer (uNK) cells from E7.5 onwards. This work provides the first comprehensive description of the hitherto ill-defined spatiotemporal binding distribution of BS-I lectin in the fetal and maternal placenta between E6.5 and E12.5, thereby contributing to glycome elucidation during placentation. It also establishes BS-I lectin positivity as a novel pan-trophoblast marker during early placentation and as a new marker for mature uNK cells from E7.5 onwards.

Radiofrequency volumetric tissue reduction of the inferior turbinate in a sheep model

To validate the sheep model for endoscopic nasal surgery, and to utilize this model to compare the immediate and early postoperative histopathologic effects of four electrosurgical turbinate reduction techniques. Pilot comparative study of electrosurgical devices for inferior turbinate reduction using a sheep model. Three radiofrequency devices (one monopolar and two bipolar) were compared to monopolar electrosurgery in a sheep model of inferior turbinate reduction. Procedures were performed according to device manufacturer guidelines using standard endoscopic instruments. Normative acoustic rhinometry data were obtained for the sheep model. Histopathologic analysis of turbinate specimens was performed at postoperative day 0 and 21. Turbinate reduction was performed on seven sheep, one procedure on each side, yielding 14 turbinate specimens. Acoustic rhinometry was validated in the sheep model and demonstrated increased nasal volumes following decongestion and turbinate reduction. Submucosal destruction of glands and venous sinusoids and replacement with fibrosis were demonstrated as a common mechanism of action for all four electrosurgical devices. Epithelial disruption was seen with all devices on postoperative day 0. Squamous metaplasia and normal respiratory epithelial regeneration were documented variably between devices at postoperative day 21. The sheep model is useful for study of both the anatomic and histopathologic effects of endonasal procedures. Standard endoscopic instruments and acoustic rhinometry can be used in this model with reproducible results. In this pilot animal study, radiofrequency devices for inferior turbinate reduction demonstrated greater preservation of normal nasal mucosal respiratory epithelium when compared to monopolar electrosurgery.

Subjective Nasal Fullness and Objective Congestion

How well do subjective descriptions of the sensation of nasal closure or absence of nasal patency agree with objective measures of nasal geometry and airflow? Problems with this concept begin with terminology. "Congestion" has been applied to both the subjective and objective measures. Therefore, the term "fullness" will be used to describe perceptions of nasal mucosal heaviness or blockage that subjects with allergic rhinitis articulate. "Congestion" will refer to the objective measures used to assess patency. Sensations attributed to the nasal mucosa are highly integrated interpretations summed from multiple subsets of nociceptive and other neurons. Activation of sensor systems is required to depolarize afferent neurons. These sensors and other receptor proteins can be modulated by inflammation as part of the neural plasticity that leads to increased sensitivity to nasal stimuli. This plasticity and hyperalgesia may extend from the afferent neuron to spinal cord dorsal horn synapses, and regulatory and analytical regions of the brainstem and cerebrum. Although glandular hypersecretion can deliver obstructing material into the nasal cavities, the dilation of deep venous sinusoids is the strongest factor regulating nasal airspace volumes. There is a long history of attempts to correlate subjective sensations to objective measurements such as airflow resistance (rhinomanometry), nasal wall geometry (acoustic rhinometry), and peak nasal inspiratory flow. The medical evidence supporting each method has been analyzed on the basis of the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) system. These results provide a starting point for linking the outcomes of pathophysiological processes with a patient's psychometrically calibrated sensation of airflow.

Radiographic and Anatomic Characterization of the Nasal Septal Swell Body

To analyze the radiographic, anatomic, and histologic characteristics of the nasal septal swell body. Computer-aided analysis of magnetic resonance images (MRIs) and histologic examination of cadaveric nasal septa. Tertiary medical center. Fifty-four head MRI studies were performed on adult live patients; we also used 10 cadaveric nasal septa. Radiographic dimensions of the swell body and distances to other nasal landmarks were measured. Nasal septa and swell body histologic characteristics were evaluated using light microscopy. Relative proportions of vascular, connective, and glandular tissues within the swell body and the adjacent septum were compared. The swell body was fusiform shaped and located anterior to the middle turbinate, with mean (SD) width of 12.4 (1.9) mm; height, 19.6 (3.2) mm; and length, 28.4 (3.5) mm. The epicenter was 24.8 (2.9) mm from the nasal floor, 43.9 (4.1) mm from the nasal tip, and 39.0 (4.6) mm from the sphenoid face. Histologic analyses revealed that, compared with adjacent septal mucosa, the swell body contained significantly more venous sinusoids (37% vs 16%, P<.001) and fewer glandular elements (28% vs 41%, P<.001). The swell body is a conserved region of the septum located anterior to the middle turbinate approximately 2.5 cm above the nasal floor. The high proportion of venous sinusoids within the swell body suggests the capacity to alter nasal airflow. Additional study is required before these findings are used in a clinical setting.

Fatal Venous Air Embolism During Shoulder Arthroscopy

Venous air embolism is a potential surgical complication when a negative pressure gradient exists between the surgical site and the right atrium of the heart. It occurs more commonly when the operative site is over the heart, the pressure of gas in the body cavity exceeds that of the venous sinusoids (15 to 30 mm Hg), air rather than carbon dioxide is injected, or the venous sinusoids of bone marrow are exposed1,2. Shoulder arthroscopy satisfies many of these criteria: the beach-chair and lateral decubitus positions place the surgical site over the right atrium, the standard settings for arthroscopic pumps are at pressures of >30 mm Hg, air bubbles are often observed entering the joint, and venous sinusoids are exposed anytime that osseous work (i.e., distal clavicular excision, acromioplasty, or fracture repair) is performed. Two case reports of fatal venous air embolism following knee arthroscopy3,4 with intentional air insufflation have appeared in the literature, but we are not aware of any reported case following liquid-only arthroscopy. We present the case of a patient undergoing revision arthroscopic rotator cuff repair and distal clavicular excision who experienced acute intraoperative cardiopulmonary collapse and was resuscitated, but died on postoperative day 14. The patient was undergoing liquid-only arthroscopy, and we postulated that air entered the joint through an unrecognized air reservoir: commercially available 3-L arthroscopic fluid bags. A forty-seven-year-old woman presented with a six-month history of severe pain in the right shoulder. The history, physical examination, and magnetic resonance imaging revealed a small, full-thickness tear of the supraspinatus tendon. After the failure of six months of conservative treatment, she elected to undergo arthroscopic supraspinatus repair and subacromial …