Towards a standardized framework for AI-assisted, image-based monitoring of nocturnal insects.

Automated sensors have potential to standardize and expand the monitoring of insects across the globe. As one of the most scalable and fastest developing sensor technologies, we describe a framework for automated, image-based monitoring of nocturnal insects-from sensor development and field deployment to workflows for data processing and publishing. Sensors comprise a light to attract insects, a camera for collecting images and a computer for scheduling, data storage and processing. Metadata is important to describe sampling schedules that balance the capture of relevant ecological information against power and data storage limitations. Large data volumes of images from automated systems necessitate scalable and effective data processing. We describe computer vision approaches for the detection, tracking and classification of insects, including models built from existing aggregations of labelled insect images. Data from automated camera systems necessitate approaches that account for inherent biases. We advocate models that explicitly correct for bias in species occurrence or abundance estimates resulting from the imperfect detection of species or individuals present during sampling occasions. We propose ten priorities towards a step-change in automated monitoring of nocturnal insects, a vital task in the face of rapid biodiversity loss from global threats. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.

Delayed onset of benign pleural effusion following concurrent chemoradiotherapy for inoperable non-small-cell lung cancer.

Chronic benign pleural effusion (BPE) is a rare complication of concurrent chemoradiotherapy (CRT) for inoperable stage IIIA non-small-cell lung cancer (NSCLC). This report presents three cases of BPE, the workup to differentiate this benign condition from recurrence of cancer and recommends a pleural biopsy as part of the diagnostic process. These inflammatory exudates often remain indolent, and may not require drainage or surgical intervention. In the absence of clinical, radiological and pathological evidence of recurrent disease, we recommend clinicians manage these patients expectantly, using regular clinical assessment and imaging.

Outcomes of an Australian testing programme for epidermal growth factor receptor mutations in non-small cell lung cancer.

BACKGROUND: Molecular characterisation of non-squamous non-small-cell lung cancer (NSCLC) is required to direct optimal treatment. Treatment of NSCLC with inhibitors of epidermal growth factor receptor (EGFR) tyrosine kinase (EGFR-TKI) should be guided by the presence of activating mutations of the EGFR gene. AIM: To gain insight into the rate of testing, the range of tissues samples, test utility and outcome when cost of testing as a barrier to access is removed in the Australian setting. METHODS: In October 2010, a sponsored programme was commenced to gather data on EGFR gene mutation testing in Australia. Partnering laboratories were funded for provision of de-identified results. For participating patients, the programme supported the test charge. Mutation testing was performed using Sanger sequencing of exons 18-21 of the EGFR. RESULTS: Samples 2013 were submitted from 2012 patients. Full sequencing was achieved in 1717 (85%). Failure of full sequencing was more likely in samples derived from fine needle aspiration(FNA) biopsy than tissue biopsy or pleural/pericardial fluid cell blocks OR 3.1 (95% CI 1.9-5.2). There were 359 mutations seen in 337 patients. 14.5% of cases had a classical mutation conferring sensitivity to EGFR-TKI. In addition there was a range of less common mutations - some predicting responses and others of uncertain significance. 1.4% of cases had mutations associated with non-responsiveness to EGFR-TKI. CONCLUSIONS: EGFR gene mutation testing is feasible on local and interstate lung cancer samples. The rate of valid test outcomes is high, but FNA samples are associated with more frequent test failure.

Effects of a cosmetic 'anti-ageing' product improves photoaged skin [corrected].

BACKGROUND: Very few over-the-counter cosmetic 'anti-ageing' products have been subjected to a rigorous double-blind, vehicle-controlled trial of efficacy. Previously we have shown that application of a cosmetic 'anti-ageing' product to photoaged skin under occlusion for 12 days can stimulate the deposition of fibrillin-1. This observation infers potential to repair and perhaps clinically improve photoaged skin. OBJECTIVE: We examined another similar over-the-counter cosmetic 'anti-ageing' product using both the patch test assay and a 6-month double-blind, randomized controlled trial (RCT), with a further 6-month open phase to assess clinical efficacy in photoaged skin. METHODS: For the patch test, commercially [corrected] available test product and its vehicle were applied occluded for 12-days to photoaged forearm skin (n = 10) prior to biopsy and immunohistochemical assessment of fibrillin-1; all-transretinoic acid (RA) [corrected] was used as a positive control. Sixty photoaged subjects were recruited to the RCT (test product, n = 30 vs. vehicle, n = 30; once daily for 6-months; face & hands) [corrected] with clinical assessments performed at recruitment and following 1-, 3- & 6-months of use [corrected]. Twenty-eight subjects had skin biopsies (dorsal wrist) at baseline and at 6 months of treatment for immunohistochemical assessment of fibrillin-1 (test product, n = 15; vehicle, n = 13). All subjects [corrected] received test product for a further 6-months. Final clinical assessments were performed at the end of this open period; 27 subjects received test product for 12-months [corrected]. RESULTS: In the 12-day patch test assay, we observed significant immunohistological deposition of fibrillin-1 in skin treated by test product and RA as compared to untreated baseline (P = 0.005 and 0.015 respectively). In the clinical RCT, at 6 months, compared to baseline assessment, 43% of subjects on test product had an improvement in facial wrinkles (P = 0.013), whereas only 22% of subjects using vehicle had clinical improvement (P = ns). Between group comparison of test product and vehicle was non-significant (P = 0.10). After 12 months, there was a significant benefit of test product over that projected for vehicle (70% vs. 33% of subjects improving; combined Wilcoxon rank tests, P = 0.026). There was significant deposition of fibrillin-1 in skin treated for 6 months with test product (mean +/- SE; vehicle, 1.84 +/- 0.23; test product, 2.57 +/- 0.19; P = 0.019). CONCLUSION: An over-the-counter cosmetic 'anti-ageing' product demonstrated clear benefit over vehicle in fibrillin-1 deposition over a 6-month trial period. There was a corresponding but non-significant trend towards clinical improvement in facial wrinkles. Clinical improvements in the treated group were increased after a further 6-months of use. This study demonstrates that a cosmetic may improve the appearance of wrinkles and further supports the use of fibrillin-1 as a robust biomarker for repair of photoaged dermis.

Repair of photoaged dermal matrix by topical application of a cosmetic 'antiageing' product.

BACKGROUND: Photoaged skin is characterized by coarse and fine wrinkles. The mechanism of wrinkle formation appears to involve changes to components of the dermal extracellular matrix. Topical treatment with all-trans retinoic acid (RA) can repair photoaged dermal matrix; this is regarded as the 'gold standard' against which repair agents are judged. To date, little is known regarding the ability of over-the-counter 'antiageing' products to repair photoaged skin. OBJECTIVES: We used a modified occluded patch test to ascertain whether topical applications of cosmetic 'antiageing' products are able to repair photoaged human skin. METHODS: Commercially available test products [basic moisturizer, 'antiageing' cream containing different active complex levels (6% active: lipopentapeptide, white lupin peptides, antioxidants, retinyl palmitate; 2% active: lipopentapeptide, white lupin peptides, antioxidants)] were applied under occlusion for 12 days prior to biopsy and histological assessment in photoaged volunteers (n=9). RA was used as a positive control. RESULTS: In agreement with previous studies, the patch-test study revealed that RA produced significant fibrillin-1 deposition in the papillary dermis (P<0.01) but had little effect on procollagen I or matrix metalloproteinase-1 expression. The 6% total active complex formulation, however, increased the deposition of fibrillin-1 and procollagen I (P<0.01, P<0.05, respectively). CONCLUSIONS: This study indicates that in an in vivo 12-day patch test an over-the-counter cosmetic product can induce changes in photoaged dermal extracellular matrix, which are indicative of repair.

Salicyloyl-phytosphingosine: a novel agent for the repair of photoaged skin.

In recent years the importance of sphingolipids (cerebrosides, sphingomyelin, ceramides, sphingosine-1-phospate, etc.) in skin biology is receiving an increasing interest. Not only are ceramides essential for the barrier function of the skin, especially through their phytosphingosine, sphingosine and 6-hydroxysphingosine derivatives, they are now also known to be cell-signalling mediators which can improve epidermal differentiation. However, their effects on dermal anti-ageing markers and reduction of wrinkles have not been established. In this study, we were interested in the effects of a sphingolipid derivative, salicyloyl-phytosphingosine (SP), because of the known independent beneficial effects of salicylic acid and phytosphingosine on skin. Both of these agents are known to reduce the activities of the activator protein-1 transcription factor, in a manner similar to that observed with retinoic acid (RA) treatment. Through this mechanism, RA was shown to reduce the levels of matrix metalloproteases (MMPs) and the increase levels of extracellular matrix proteins. Therefore, we examined the effects of SP on procollagen-I synthesis in fibroblasts in vitro, its effects in vivo on the expression of dermal markers such as fibrillin-1, procollagen-I and MMP-1 immunochemically in biopsies taken from a short-term occluded patch test protocol and, its effects on periorbital wrinkle reduction over 4 weeks using Fast Optical In Vivo Topometry of Human Skin. In vitro we observed a significant increase in the production of procollagen-I by adult human fibroblasts (two fold increase, P < 0.01) which encouraged us to test the effects of SP in vivo. Initially, test products (SP at 0.05% and 0.2%, all-trans RA (0.025%) and vehicle were applied under occlusion for 8 days prior to biopsy and histological assessment in photoaged volunteers (n = 5). Increased deposition of fibrillin-1 and procollagen-I, together with reductions in the levels of MMP-1, were observed for the SP treatments (P < 0.05). Similar effects were observed for RA, except for the increases in procollagen-I. With these beneficial effects on the basement membrane and papillary dermal markers, we evaluated the effects of SP in an oil-in-water (O/W) cream for its effects in reducing the appearance of periorbital wrinkles in a 4-week, half-face clinical study compared to placebo cream (moderately photoaged female subjects aged 41-69 years; n = 30). Clear reductions in wrinkle depth and Rz (skin smoothness) together with Ra (skin roughness) parameters were observed (P < 0.05), indicating an anti-wrinkle benefit. In conclusion, this series of studies demonstrated for the first time that a ceramide derivative, such as that SP, was a novel agent for the repair of photoaged skin and highlight its effects at the cellular, tissue and organ levels.

Infliximab for the treatment of pyoderma gangrenosum: a randomised, double blind, placebo controlled trial.

BACKGROUND: Pyoderma gangrenosum (PG) is a chronic ulcerating skin condition that often occurs in association with inflammatory bowel disease. There have been a number of reports of PG responding to infliximab, a monoclonal antibody against tumour necrosis factor alpha. AIM: In the first randomised placebo controlled trial of any drug for the treatment of PG, we have studied the role of infliximab in this disorder. SUBJECTS: Patients 18 years of age or older with a clinical diagnosis of PG were invited to take part. METHODS: Patients were randomised to receive an infusion of infliximab at 5 mg/kg or placebo at week 0. Patients were then assessed at week 2 and non-responders were offered open labelled infliximab. The primary end point was clinical improvement at week 2, with secondary end points being remission and improvement at week 6. RESULTS: Thirty patients were entered into the study. After randomisation, 13 patients received infliximab and 17 patients received placebo. At week 2, significantly more patients in the infliximab group had improved (46% (6/13)) compared with the placebo group (6% (1/17); p = 0.025). Overall, 29 patients received infliximab with 69% (20/29) demonstrating a beneficial clinical response. Remission rate at week 6 was 21% (6/29). There was no response in 31% (9/29) of patients. CONCLUSIONS: This study has demonstrated that infliximab at a dose of 5 mg/kg is superior to placebo in the treatment of PG. Open label treatment with infliximab also produced promising results. Infliximab treatment should be considered in patients with PG.

Adhesion molecule expression on epithelial cells infected with respiratory syncytial virus.

Respiratory epithelium is both a target and an effector of airway inflammation. Adhesion molecules on epithelium play an important role in a variety of airway diseases. Respiratory syncytial virus (RSV) is the most important pathogen for airway diseases in infants. The expression of adhesion molecules on epithelium in RSV infection, however, is unclear. The expression of selected adhesion molecules and major histocompatibility complex (MHC) class I and II antigens on a human alveolar type II epithelial cell line (A549) infected with RSV was investigated by means of flow cytometry and immunocytochemistry. The results showed that intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were expressed on A549 cells at a low level. E-cadherin and MHC class I antigen were constitutively expressed on the cells. RSV infection of A549 cells significantly upregulated the expression of ICAM-1, VCAM-1 and MHC class I and II antigens on these cells. RSV infection also altered the expression of E-cadherin on A549 cells. Immunostaining showed that E-cadherin was mainly upregulated around or in RSV-induced giant cells. These data suggest that respiratory syncytial virus infection of respiratory epithelial cells enhances the expression of adhesion molecules and major histocompatibility complex antigens. These changes may play an important role in the pathophysiology of respiratory syncytial virus disease.

Shedding of L-selectin and PECAM-1 and upregulation of Mac-1 and ICAM-1 on neutrophils in RSV bronchiolitis.

Bronchiolitis is characterized histologically by epithelial necrosis and peribronchial infiltration of leukocytes, with a high percentage of neutrophils in the airways. We investigated the expression of adhesion molecules (CD11a, CD11b, CD18, CD31, CD54, and CD62L) on neutrophils from nasopharyngeal aspirates (NPAs) and peripheral blood (PB) of infants with respiratory syncytial virus (RSV)-induced bronchiolitis. The expression of CD31 and CD62L on neutrophils from NPAs is decreased and the expression of CD11b, CD18, and CD54 on neutrophils from NPAs is increased compared with cells from PB of RSV-infected infants. The expression of CD18 and CD54 on neutrophils from PB of RSV-infected infants is also increased compared with cells from PB of control infants. Shedding of CD31 and CD62L on neutrophils in RSV infection may contribute to the neutrophil emigration from blood to airways; the upregulation of Mac-1 (CD11b/CD18) and CD54 on neutrophils may help explain the high percentage of neutrophils in the airways of RSV bronchiolitis; and the upregulation of Mac-1 may be involved in the increased neutrophil-airway epithelial adhesion in RSV infection.

Neutrophils induce damage to respiratory epithelial cells infected with respiratory syncytial virus.

The mechanisms by which respiratory syncytial virus (RSV) infection induces bronchiolitis and airway disease are unclear. The presence of large numbers of polymorphonuclear leukocytes (PMN) in the airways of infants with RSV infection suggests a potential role of PMN in airway injury associated with RSV infection. To investigate the potential role of neutrophils in RSV bronchiolitis, human alveolar type II cells (A549 cells) were infected with different doses of RSV for 6-48 h. A 51Cr-releasing assay was used to measure PMN-induced damage and image analysis was used to determine PMN adhesion and detachment of epithelial cells. The results showed that RSV infection of epithelial cells enhanced PMN adherence in a dose- and time-dependent pattern, RSV infection alone could damage and detach epithelial cells to a limited extent and PMN significantly augmented RSV infection-induced damage and detachment of epithelial cells. These data suggest that respiratory syncytial virus infection of respiratory epithelial cells enhances neutrophil adhesion to the epithelium and that activated neutrophils augment the damage and detachment of epithelium infected with the virus. Polymorphonuclear leukocytes may contribute to the pathogenesis of respiratory syncytial virus airway disease by inducing epithelial damage and cell loss.

The apoptosis of neutrophils is accelerated in respiratory syncytial virus (RSV)-induced bronchiolitis.

Neutrophils are the predominant inflammatory cell in the lung tissues and airways in RSV infection, and can augment the epithelial cell damage induced by RSV. Neutrophil apoptosis has been suggested to be a mechanism to reduce the potential for tissue injury. The apoptosis of neutrophils from nasopharyngeal aspirates (NPA) (n = 19) and peripheral blood (PB) of infants with RSV bronchiolitis (n = 11) and PB from healthy controls (n = 9) was investigated. Monoclonal antibody against CD95 (Fas) and a binding protein Annexin V were used to determine the apoptosis of neutrophils. The expression of CD11b and CD18 on neutrophils was also detected with flow cytometry. The mean fluorescence intensity (MFI) of CD95 on neutrophils from RSV+ NPA was increased compared with cells from control PB (73.6 +/- 7.6 versus 31.5 +/- 4.3); the MFI of Annexin V, CD11b and CD18 on neutrophils from RSV+ NPA was up-regulated compared with cells from both control PB (105.3 +/- 18.1 versus 11.8 +/- 1.5; 1683 +/- 153.3 versus 841.1 +/- 72.3; 517 +/- 50.5 versus 147 +/- 8.7, respectively) and RSV+ PB (105.3 +/- 18.1 versus 35.8 +/- 4.1; 1683 +/- 153.3 versus 818 +/- 141.2; 517 +/- 50.5 versus 260 +/- 25.8, respectively). Furthermore, the percentage of neutrophils expressing Annexin V and the MFI of CD18 on neutrophils from RSV+ PB were increased compared with neutrophils from control PB. In addition, both CD11b (MFI) and CD18 (MFI) correlated with Annexin V (MFI) on neutrophils. We conclude that neutrophil apoptosis in RSV bronchiolitis is accelerated; and CD11b/CD18 may play an important role in RSV infection by influencing neutrophil apoptosis.

Upregulation of substance P receptors in angiogenesis associated with chronic airway inflammation in rats.

In rat airways, substance P released from sensory nerves induces plasma leakage via neurokinin-1 (NK1) receptors on endothelial cells. In pathogen-free rats, both leakage and endothelial NK1 receptors are most abundant in postcapillary venules. In Mycoplasma pulmonis-infected rats, extensive angiogenesis occurs in the tracheal mucosa. The capillary-sized (< 10 microns in diameter) angiogenic blood vessels are abnormally sensitive to substance P. The aim of this study was to determine whether increased expression of NK1 receptors contributes to this abnormal sensitivity. Fischer 344 rats were infected with M. pulmonis and were challenged with substance P (5 micrograms/kg i.v.), and then plasma leakage in the tracheal mucosa was measured by extravasation of Monastral blue (30 mg/kg i.v.). NK1 receptors on endothelial cells were localized by immunohistochemistry. Five minutes after substance P, NK1 receptor-immunoreactive endosomes were five times more abundant in endothelial cells of angiogenic capillaries in M. pulmonis-infected rats than in corresponding capillaries in pathogen-free controls (17.1 +/- 2.3 vs. 3.5 +/- 0.4 endosomes/100 micron 2 of endothelial surface). Endosomes were slightly more abundant in postcapillary venules 15-35 microns in diameter in infected rats (23.0 +/- 0.6 vs. 19.2 +/- 0.7 endosomes/100 micron 2). Similarly, after substance P, angiogenic capillaries had much more Monastral blue labeling (area density: 18.8 +/- 1.5 vs. 2.9 +/- 0.5% of vessel wall), whereas postcapillary venules had about the same amount of labeling (36.0 +/- 3.7 vs. 34.1 +/- 1.8%). We conclude that increased expression of NK1 receptors, which are internalized into endosomes after ligand binding, contributes to the abnormal sensitivity of endothelial cells of angiogenic blood vessels to substance P in the airways of M. pulmonis-infected rats.

Characterization of tolerance to the anti-leakage effect of formoterol in rat airways.

These experiments addressed the question of whether the anti-plasma leakage action of beta2-adrenoceptor agonists in rat airways is subject to tolerance. Pathogen-free F344 rats were pretreated with the highly selective, long-acting beta2-adrenoceptor agonist, formoterol (0, 0.1, 1, 10 microg/kg, i.p.) for 7 days; 24 h later the effectiveness of acute doses of formoterol (0, 0.1, 1, 10 microg/kg, i.v.) was tested against substance P-induced plasma leakage. The anti-leakage effect of formoterol was not subject to tolerance with the low or intermediate pretreatment dose. Pretreatment with 10 microg/kg formoterol reduced the effectiveness of the 1 microg/kg acute dose but not the 10 microg/kg acute dose. We conclude that tolerance to the anti-leakage effect of formoterol can occur, but airway vessels are likely to retain functionally coupled receptors even after high dose pretreatment.

Sensory denervation by neonatal capsaicin treatment exacerbates Mycoplasma pulmonis infection in rat airways.

Mycoplasma pulmonis infection in rats results in life-long disease, characterized by chronic inflammation of the airway mucosa with widespread accumulation of lymphoid tissue, mucous cell hyperplasia, and mucosal thickening. In addition, there is angiogenesis and increased sensitivity of mucosal blood vessels to substance P (SP), so tachykinins released from sensory nerve fibers cause an abnormally large amount of plasma leakage. We sought to learn whether the sensory nerves influence the severity of the chronic inflammatory response of M. pulmonis infection. Our strategy was to destroy the nerves by capsaicin pretreatment at birth, infect the rats with M. pulmonis at 8 wk of age, and then study the animals 6 wk later. We found that capsaicin pretreatment increased the severity of the infection, exaggerated the pathological changes in the tracheal mucosa, and increased the amount of SP-induced plasma leakage, as quantified with Monastral blue. The thickness of the tracheal mucosa in these infected rats was 80% greater than in their vehicle-pretreated counterparts and 200% greater than in the pathogen-free controls. The area density of Monastral blue-labeled blood vessels averaged 20% in the infected rats pretreated with capsaicin, which represented a 40-fold increase over the leakage in the pathogen-free group. By comparison, the amount of Monastral blue labeling was only 13% in rats pretreated with vehicle (P<0.05), which was a 22-fold increase over the corresponding pathogen-free group. The number of SP-immunoreactive nerve fibers was reduced both by neonatal capsaicin and by infection (87 and 63% reductions, respectively); but when the two conditions were combined, their effects were not additive (79% reduction), perhaps because of nerve regrowth. We conclude that destruction of sensory nerves increases the severity of infection- induced chronic inflammation in the airway mucosa, with exaggerated mucosal thickening, angiogenesis, plasma leakage, and nerve remodeling.

Substance P (NK1) receptor immunoreactivity on endothelial cells of the rat tracheal mucosa.

Substance P released from sensory nerve fibers causes plasma leakage through an action on neurokinin-1 (NK1 or substance P) receptors. However, it is unknown whether the leakage results from a direct action of substance P on endothelial cells. We determined the distribution of NK1 receptors at sites of plasma leakage in the rat tracheal mucosa, using NK1 receptor-immunoreactive endosomes as markers of substance P-induced receptor internalization. We found that immunoreactive endosomes were located in the endothelial cells of venules and capillaries but not in those of arterioles. Five minutes after vagal stimulation for 1 min, the number of immunoreactive endosomes in endothelial cells was increased 5-fold in postcapillary venules (mean of 17.4 endosomes/100 micron2 compared with a baseline value of 3.4), 15-fold in collecting venules (12.1 compared with 0.8), and 4-fold in capillaries (2.5 compared with 0.7). No endosomes were found in arterioles under either condition. The number of immunoreactive endosomes in individual vessels corresponded to the amount of stimulus-induced plasma leakage. Both the receptor internalization and the plasma leakage were blocked by the selective NK1 receptor antagonist SR-140333 (100 microgram/kg iv). Although both substance P (5 microgram/kg iv) and platelet-activating factor (5 microgram/kg iv) caused plasma leakage, only substance P induced receptor internalization. We conclude that substance P, released from sensory nerve fibers, causes plasma leakage through a direct action on endothelial cells of venules, and that this action is followed by the internalization of NK1 receptors into endosomes.

Neurogenic inflammation. A model for studying efferent actions of sensory nerves.

Several lines of evidence suggest that sensory nerves of the carotid body have an efferent function in addition to their afferent function of conducting chemoreceptive impulses to the brain. However, it has been difficult to document the release of substances from sensory nerve terminals on glomus cells and to determine whether such an efferent function plays a role in chemoreception. By comparison, the phenomenon of neurogenic inflammation has been relatively easy to study in rats and guinea pigs and has proven to be an informative model system for analyzing efferent actions of sensory nerves. The main characteristic of neurogenic inflammation is plasma leakage. Chemical irritants that activate unmyelinated sensory nerves cause plasma leakage in the skin, respiratory tract, and other organs by triggering the release of substances from sensory nerve fibers. Substance P, which is synthesized and released by some sensory neurons, appears to be the main active mediator, although other tachykinins, calcitonin gene-related peptide, and perhaps other peptides may also participate. Neurogenic inflammation results from the action of substance P on NK1 receptors, as demonstrated by selective NK1 receptor agonists and antagonists. The NK1 receptors involved in plasma leakage are located on the endothelial cells of postcapillary venules and collecting venules. Within seconds of the activation of NK1 receptors by substance P, gaps form in the endothelium of target vessels. The endothelial gaps are transient, and the leak normally ends in a few minutes. However, the magnitude of the response can increase in pathological conditions such as Mycoplasma pulmonis infection in rats, which results in a chronic inflammatory disease of the respiratory tract. The infected airway mucosa becomes abnormally vascular as a result of angiogenesis, and the endothelial cells of the newly formed vessels express increased numbers of NK1 receptors and thus are abnormally sensitive to substance P. Studies of neurogenic inflammation not only have helped to understand the efferent actions of sensory nerves but also have given insight into the mechanism and consequences of inflammatory changes in endothelial cells and in the plasma leakage that follows.

Dexamethasone and oxytetracycline reverse the potentiation of neurogenic inflammation in airways of rats with Mycoplasma pulmonis infection.

Mycoplasma pulmonis infection in rats causes a chronic inflammatory airway disease. Along with extensive remodeling of the airway mucosa, lymphocytic infiltrates, angiogenesis, and mucosal thickening, there is an abnormal sensitivity of the blood vessels to mediators that evoke "neurogenic inflammation". As a result, substance P, a peptide released from sensory nerves, produces an unusually large amount of plasma leakage. These changes can be prevented or reduced by prophylactic treatment with antibiotics, but it is unknown whether the extensive remodeling of the airway mucosa and potentiation of neurogenic inflammation can be reversed once they are established. We addressed this issue in F344 rats that were infected with M. pulmonis at 8 wk of age. Six weeks later, the rats were treated daily with an antibiotic (oxytetracycline, 20 mg/kg intramuscularly), to reduce the number of infecting organisms, or with an antiinflammatory steroid (dexamethasone, 0.5 mg/kg intraperitoneally), to reduce the inflammatory and immunologic response to the infection. Sham-treated infected rats received daily injections of 0.9% NaCl. After 1, 2, or 4 wk of treatment the rats were anesthetized and then challenged with substance P (5 micrograms/kg intravenously). The sham-treated rats had pathologic changes in their airways typical of severe M. pulmonis infection, and had as much as a threefold increase in substance P-induced plasma leakage. By comparison, after 4 wk of treatment with oxytetracycline or dexamethasone, the chronic inflammation was nearly resolved and the response to substance P was in the normal range. Unexpectedly, dexamethasone, like oxytetracycline, reduced the number of infecting organisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct observation of substance P-induced internalization of neurokinin 1 (NK1) receptors at sites of inflammation.

Substance P (SP) can cause plasma leakage at sites of inflammation by binding to neurokinin type 1 (NK1) receptors on the surface of endothelial cells. Internalization after ligand binding could reduce the number of NK1 receptors on the cell surface and thus participate in the desensitization and resensitization of the inflammatory response to SP. By using an antibody to the receptor, we directly observed SP-induced internalization of NK1 receptors into endosomes in endothelial cells of postcapillary venules in the rat tracheal mucosa. In the absence of SP, an average of 15 immunoreactive endosomes were present per endothelial cell. After an intravenous injection of SP, the number of immunoreactive endosomes peaked at 107 per cell at 3 min and gradually returned to the baseline by 120 min. In parallel experiments we observed that when cultured cells transfected with the NK1 receptor were exposed to rhodamine-SP and an antibody to an extracellular Flag epitope of the NK1 receptor, the SP was internalized with the receptor antibody. Both in the cultured cells and in the endothelial cells of intact animals, the prompt SP-induced internalization was accompanied by rapid, long-lasting desensitization to SP. These studies suggest that internalization of NK1 receptors by endothelial cells may be one of the mechanisms that limit the amount of plasma leakage at sites of inflammation.