FRI0196 INVOLVEMENT OF THE PULMONARY ARTERIES IN PATIENTS WITH TAKAYASU ARTERITIS

Background:

Takayasu arteritis (TA) is a chronic, granulomatous large-vessel vasculitis. It involves the aorta and its main branches predominantly, and leads to vascular thickness, stenosis and occlusion [1]. Besides the aorta and its branches, pulmonary arteries (PAs) are involved in TA. PAs have been reported to be involved in 6.9% to 80% of TA patients from different populations [2-3].

Objectives:

We investigated the clinical characteristics, pulmonary parenchymal features and cardiac functions in TA patients with PA involvement by combining multiple imaging modalities (MRA, CTA, PET-CT, lung VQ scan, echocardiography and high-resolution computed tomography (HRCT)). Our aim was to elicit better understanding of TA patients with PA involvement to aid rational treatment for these patients and improve their prognosis.

Methods:

We enrolled 216 patients with TA from a large prospective cohort. PAI was assessed in each patient based on data from magnetic resonance angiography/computed tomography angiography. Pulmonary hypertension, cardiac function, and pulmonary parenchymal abnormalities were evaluated further in patients with PAI based on echocardiography, New York Heart Association Functional Classification and pulmonary computed tomography, respectively. These abnormalities related to PAI were followed up to evaluate treatment effects.

Results:

PAI was detected in 56/216 (25.93%) patients, which involved the pulmonary trunk, main PAs and small vessels in the lungs. Among patients with PAI, 28 (50%) patients were accompanied by pulmonary hypertension, which was graded as ‘severe’ in 9 (16.07%), ‘moderate’ in 10 (17.86%) and mild in 9 (16.07%). Forty (71.43%) patients had cardiac insufficiency (IV: 6, 10.71%; III: 20, 35.71%; II: 14, 25.00%). Furthermore, 21 (37.50%) patients presented with abnormal parenchymal features in the area corresponding to PAI (e.g., the mosaic sign, infarction, bronchiectasis). During follow-up, two patients died due to abrupt pulmonary thrombosis. In the remaining patients, the abnormalities mentioned above improved partially after routine treatment.

Conclusion:

PA involvement is very common in TA patients. Physicians should be alerted to PA involvement even if obvious pulmonary symptoms are absent because they can cause PH, cardiac insufficiency as well as pulmonary parenchymal lesions, which will worsen the prognosis.

References:

[1]M.L.F. Zaldivar Villon, J.A.L. de la Rocha, L.R. Espinoza. Takayasu Arteritis: Recent Developments. Curr Rheumatol Rep 2019; 21: 45.

[2]N. Matsunaga, K. Hayashi, I. Sakamoto, et al. Takayasu arteritis: protean radiologic manifestations and diagnosis. Radiographics 1997; 17: 579-594.

[3]M. Bicakcigil, K. Aksu, S. Kamali, et al. Takayasu’s arteritis in Turkey - clinical and angiographic features of 248 patients. Clin Exp Rheumatol 2009; 27: S59-64.

Figure 1.

Imaging of PA lesions in TA patientsA:Dilationof the pulmonary trunk; B: thickness of the pulmonary trunk; C: stenosis of the right main PA; D: embolism of lower PAs on both sides; E: inflammation of the pulmonary-trunk root upon PET–CT; F: absence of left PAs and stenosis of the right main PA; G–I: pulmonary MRA (G), CTA (H) and VQ scan (I) of a patient with TA. MRA shows a fine right main PA and low perfusion in the right lung (G); CTA demonstrates a fine right main PA and fewer PA branches in the right lung (H); lung VQ scan shows multiple arterial emboli in the right lung and obvious less blood supply to the right lung.

Figure 2.

Pulmonary lesions on HRCT.A: Themosaicsign in the left lung; B: Pulmonary infarction of the right middle lobe; C: Mild pleural effusion on the left side; D: Bronchiectasis in the right lung; E–F: Ground-glass opacity (E) in the right upper lobe of a TA patient with an embolism of the right upper pulmonary branches (F); G–I: Cavitation (G) and mass-like consolidation (H) in the patient with severe stenosis of right main pulmonary artery (I).

Acknowledgments:

None

Disclosure of Interests:

None declared

Colorimetric Sensor for Thiocyanate Based on Anti-aggregation of Gold Nanoparticles in the Presence of 2-Aminopyridine

Based on the anti-aggregation mechanism of citrate stabilized gold nanoparticle (AuNPs), a new specific and sensitive colorimetric sensor for thiocyanate (SCN^-) was developed. In this scheme, the AuNPs were aggregated in the presence of the aggregating agent 2-aminopyridine (2-AP) due to electrostatic attraction. The solution color changed from red to blue. When SCN^- was present, SCN^- formed a sulfur-gold bond with the AuNPs to protect the AuNPs from aggregation. Thiocyanate can be detected by the color change of the solution from blue to red. The results showed that the absorbance ratio A₆₇₅/A₅₂₀ was linear with the concentration of SCN^- in the range of 0.4 - 1.2 μmol L^-1 by UV-Vis spectroscopy. The limit of detection (LOD) of this assay was 0.37 μmol L^-1. The system also had excellent selectivity and anti-interference ability. In addition, this method was successfully used for the detection of SCN^- in actual water samples and achieved good results.

[Clinical effectiveness of simultaneous reconstructions of multiple joint scar contracture deformity of limb]

Objective: To explore the clinical effects of simultaneous reconstruction of multiple joint scar contracture deformity of limb. Methods: From January 2010 to June 2018, 24 patients with multiple joint scar contracture deformity of the same limb were reconstructed in simultaneous operations in Xiangya Hospital of Central South University, including 16 males and 8 females, aged 3-42 years, with 15 patients having deformities in the upper limbs and 9 patients having deformities in the lower limbs. One operation was performed to repair contracture deformity of axillary fossa and elbow in 3 patients, cubital fossa and palmar of wrist in 4 patients, cubital fossa and hand in 5 patients, palmar of wrist, palm, and palmar of finger in 3 patients, groin and medial knee in 2 patients, popliteal fossa and posterior ankle in 1 patient, and anterior ankle and dorsum of foot in 6 patients. After the release of various joint scar contractures, the area of skin defect was 140 to 580 cm(2). Autologous full-thickness skin grafts were used in 7 patients, autologous medium-thickness skin grafts were used in 4 patients, autologous full-thickness skin grafts combined with local skin flaps were used in 9 patients, and allogeneic acellular dermal matrix and autologous thin skin grafts were used in 4 patients. Comprehensive measures for rehabilitation were taken and the survival of the skin graft was observed after operation. Six months to eight years after the operation, all the patients were followed up for the functions of the affected limbs, among which the functions of the upper limbs were evaluated according to the trial standard for the evaluation of the functions of the upper limbs of the Hand Surgery Society of the Chinese Medical Association. The joint mobility, walking, and squatting function of lower extremity were examined after operation. Recurrence of contractures in all the affected limbs and reoperation were recorded. Results: The grafts survived after operation in 22 patients. Two patients had necrosis in small full-thickness skin area, of which one was healed by skin grafting after debridement, and the other one was healed after dressing changes. The deformity of scar contracture at each repaired joint was completely or partially corrected. During a follow-up for 6 to 96 months, the upper limb functions of 15 patients were rated excellent in 12 patients and good in 3 patients. Among the 9 patients of lower limb scar contractures, except for one 3-year-old child who experienced recurrence of medial knee scar contracture and underwent surgical release and skin grafting 5 years later, the remaining 8 patients basically recovered normal joint functions with pretty good outcomes. Conclusions: For continuous scar contracture deformity of multiple joints of the same limb, simultaneous surgical release and skin grafting can reduce operation frequency and obtain better outcomes of surgical operation.

Impact of mismatches in HbA1c vs glucose values on the diagnostic classification of diabetes and prediabetes

AIMS

To determine whether HbA_1c mismatches (HbA_1c levels that are higher or lower than expected for the average glucose levels in different individuals) could lead to errors if diagnostic classification is based only on HbA_1c levels.

METHODS

In a cross-sectional study, 3106 participants without known diabetes underwent a 75-g oral glucose tolerance test (fasting glucose and 2-h glucose) and a 50-g glucose challenge test (1-h glucose) on separate days. They were classified by oral glucose tolerance test results as having: normal glucose metabolism; prediabetes; or diabetes. Predicted HbA_1c was determined from the linear regression modelling the relationship between observed HbA_1c and average glucose (mean of fasting glucose and 2-h glucose from the oral glucose tolerance test, and 1-h glucose from the glucose challenge test) within oral glucose tolerance test groups. The haemoglobin glycation index was calculated as [observed - predicted HbA_1c ], and divided into low, intermediate and high haemoglobin glycation index mismatch tertiles.

RESULTS

Those participants with higher mismatches were more likely to be black, to be men, to be older, and to have higher BMI (all P<0.001). Using oral glucose tolerance test criteria, the distribution of normal glucose metabolism, prediabetes and diabetes was similar across mismatch tertiles; however, using HbA_1c criteria, the participants with low mismatches were classified as 97% normal glucose metabolism, 3% prediabetes and 0% diabetes, i.e. mostly normal, while those with high mismatches were classified as 13% normal glucose metabolism, 77% prediabetes and 10% diabetes, i.e. mostly abnormal (P<0.001).

CONCLUSIONS

Measuring only HbA_1c could lead to under-diagnosis in people with low mismatches and over-diagnosis in those with high mismatches. Additional oral glucose tolerance tests and/or fasting glucose testing to complement HbA_1c in diagnostic classification should be performed in most individuals.

Molecular correlates of response to capmatinib in advanced non-small-cell lung cancer: clinical and biomarker results from a phase I trial

BACKGROUND

Dysregulation of receptor tyrosine kinase MET by various mechanisms occurs in 3%-4% of non-small-cell lung cancer (NSCLC) and is associated with unfavorable prognosis. While MET is a validated drug target in lung cancer, the best biomarker strategy for the enrichment of a susceptible patient population still remains to be defined. Towards this end we analyze here primary data from a phase I dose expansion study of the MET inhibitor capmatinib in patients with advanced MET-dysregulated NSCLC.

PATIENTS AND METHODS

Eligible patients [≥18 years; Eastern Cooperative Oncology Group (ECOG) performance status ≤2] with MET-dysregulated advanced NSCLC, defined as either (i) MET status by immunohistochemistry (MET IHC) 2+ or 3+ or H-score ≥150, or MET/centromere ratio ≥2.0 or gene copy number (GCN) ≥5, or (ii) epidermal growth factor receptor wild-type (EGFRwt) and centrally assessed MET IHC 3+, received capmatinib at the recommended dose of 400 mg (tablets) or 600 mg (capsules) b.i.d. The primary objective was to determine safety and tolerability; the key secondary objective was to explore antitumor activity. The exploratory end point was the correlation of clinical activity with different biomarker formats.

RESULTS

Of 55 patients with advanced MET-dysregulated NSCLC, 40/55 (73%) had received two or more prior systemic therapies. All patients discontinued treatment, primarily due to disease progression (69.1%). The median treatment duration was 10.4 weeks. The overall response rate per RECIST was 20% (95% confidence interval, 10.4-33.0). In patients with MET GCN ≥6 (n = 15), the overall response rate by both the investigator and central assessments was 47%. The median progression-free survival per investigator for patients with MET GCN ≥6 was 9.3 months (95% confidence interval, 3.8-11.9). Tumor responses were observed in all four patients with METex14. The most common toxicities were nausea (42%), peripheral edema (33%), and vomiting (31%).

CONCLUSIONS

MET GCN ≥6 and/or METex14 are suited to predict clinical activity of capmatinib in patients with NSCLC (NCT01324479).

Core-shell Au@Pt Nanoparticles Catalyzed Luminol Chemiluminescence for Sensitive Detection of Thiocyanate

In this study, core-shell Au@Pt nanoparticles (Au@Pt NPs) with peroxidase catalytic activity were synthesized by the seed-mediated method, and were used to catalyze the reaction of luminol-H₂O₂ to enhance the chemiluminescence (CL) intensity. It was found that thiocyanate (SCN^-) can effectively inhibit the catalytic activity of Au@Pt NPs. Based on this phenomenon, a method to detect SCN^- by using the Au@Pt NPs-catalytic luminol-H₂O₂ CL system was established, which has an ultra-low detection limit and an ultra-wide linear range, as well as the advantages of being simple and having low-cost and convenient operation. The research mechanism indicated that SCN^- could be adsorbed on the surface of Au@Pt NPs and occupies the active sites of Pt nanostructures, which led to a decrease in the amount of Pt⁰ and a loss of the excellent catalytic activity of Au@Pt NPs. After optimizing the experimental conditions, this assay for detecting SCN^- exhibited a good linear range from 5 to 180 nM, and the low detection limit was 2.9 nM. In addition, this approach has been successfully applied to the detection of SCN^- in tap-water samples, which has practical application value and embodies good development prospects.

Clinical analysis of Chinese anti-low-density-lipoprotein-receptor-associated protein 4 antibodies in patients with myasthenia gravis

BACKGROUND AND PURPOSE

Low-density-lipoprotein-receptor-associated protein 4 (LRP4) autoantibodies have recently been detected in myasthenia gravis (MG), but little is known about the clinical characteristics associated with this serological type. In this study, the clinical features of Chinese patients with anti-LRP4 antibody-positive MG were characterized.

METHODS

A total of 2172 MG serum samples were collected from patients in various parts of China. An enzyme-linked immunosorbent assay was used to detect acetylcholine receptor (AChR) antibody and titin antibody, and cell-based assays were used to detect muscle-specific kinase antibody and LRP4 antibody. Clinical data for patients with MG were collected from different provinces in China.

RESULTS

In total, 16 (0.8%) patients with LRP4-MG were found amongst 2172 total patients, including three patients with AChR/LRP4-MG. Additionally, 13 (2.9%) patients with LRP4-MG were found amongst 455 patients with double seronegative MG. The ratio of males to females for these 13 patients was 1:1.6, and 53.8% patients were children. A total of 91.7% of cases exhibited initial ocular involvement, and 58.3% of cases exhibited simple eye muscle involvement. Responses to acetylcholinesterase inhibitors and prednisone were observed.

CONCLUSION

The expanded sample confirmed that the positive rate of LRP4 antibodies in China is lower than that in western countries. Our results highlighted the differences between LRP4-MG and other antibody groups. Children and female patients with LRP4-MG have a higher prevalence, often involving the ocular muscles and limb muscles. The clinical symptoms are mild, and satisfactory responses to treatment are often achieved.

Impact of Modifiable Risk Factors on Bone Loss During Periodontal Maintenance

Objectives:

The aim of this study was to analyze modifiable patient risk factors from dental chart histories and radiographs for progressive mild-moderate periodontitis during periodontal maintenance (PM).

Methods and Materials:

Bitewing radiographs of 442 elderly periodontal maintenance patients were taken before and after two years of periodontal maintenance. Each progressive periodontitis (PP) patient (with at least one site of posterior interproximal bone loss of ≥2 mm, n=71) was matched to a periodontitis stable (PS) patient (no sites with bone loss, n=71) of the same gender and age (±five years) to control for these variables and was compared for measurements of general patient (medical history, smoking, hygiene and compliance habits) and tooth-related (bone loss, overhangs, interproximal dimensions) factors at baseline. Fisher exact and t-tests were used to compare groups.

Results:

While the elderly PM patients with mild-moderate periodontitis were generally stable, 71 of 442 were PP patients. No significant differences from PS patients were observed at baseline with regard to the systemic factors measured. However, the PP group had less cementoenamel junction to bone length (bone loss p&lt;0.0001) and more interproximal width (2.3±1.0 mm) than did the PS group (1.7±0.6 mm, p=0.0016). This was reflected in more open sites without adjacent tooth contact in PP (42% vs 15%, p=0.0006).

Conclusions:

In the short term, systemic and behavior factors are of limited value in identifying mild-moderate periodontitis patients on PM at increased risk of bone loss. However, interproximal width and lack of adjacent tooth contacts are related to the likelihood of losing interproximal bone during periodontal maintenance, suggesting the need for restorative therapy.

Vegetarians have a lower fasting insulin level and higher insulin sensitivity than matched omnivores: A cross-sectional study

BACKGROUND AND AIMS

Potential associations of vegetarian diet patterns with fasting insulin (FI) and insulin sensitivity remain unclear. We aimed to investigate whether vegetarian diets were associated with FI and insulin sensitivity in a cross-sectional study in Chinese vegetarians and matched omnivores and then to test whether it is independent of body mass index (BMI).

METHODS AND RESULTS

This study included 279 vegetarians (73 vegans, 206 lacto-ovo-vegetarians) and 279 age- and sex-matched omnivores. Fasting blood glucose (FG) and FI concentrations were measured, and β-cell function (HOMA-β) and insulin resistance index (HOMA-IR) were used to evaluate insulin sensitivity. All blood glucose and insulin sensitivity indices were naturally log-transformed, and multiple-linear regression was used to determine the association between vegetarian diet patterns and insulin sensitivity after adjusting for confounders including BMI, visceral fat area, physical activity, sedentary time, income, alcohol consumption, and daily dietary intakes of macronutrients. Compared to omnivores, both vegan diet [β = -0.25, 95% CI: (-0.38, -0.14)] and lacto-ovo-vegetarian diet [β = -0.10, 95% CI: (-0.18, -0.01)] were negatively associated with HOMA-IR after adjusting for BMI. Vegan diet remained negatively associated with FI [β = -0.16, 95% CI: (-0.30, -0.01)] and HOMA-IR [β = -0.17, 95% CI: (-0.32, -0.03)] after adjusting for all confounders.

CONCLUSION

Vegetarian diet, especially vegan diet, is negatively associated with FI and IR, independent of BMI.

The molecular chaperone sigma 1 receptor mediates rescue of retinal cone photoreceptor cells via modulation of NRF2

Sigma 1 receptor (Sig1R), a putative molecular chaperone, has emerged as a novel therapeutic target for retinal degenerative disease. Earlier studies showed that activation of Sig1R via the high-affinity ligand (+)-pentazocine ((+)-PTZ) induced profound rescue of cone photoreceptor cells in the rd10 mouse model of retinitis pigmentosa; however the mechanism of rescue is unknown. Improved cone function in (+)-PTZ-treated mice was accompanied by reduced oxidative stress and normalization of levels of NRF2, a transcription factor that activates antioxidant response elements (AREs) of hundreds of cytoprotective genes. Here, we tested the hypothesis that modulation of NRF2 is central to Sig1R-mediated cone rescue. Activation of Sig1R in 661W cone cells using (+)-PTZ induced dose-dependent increases in NRF2-ARE binding activity and NRF2 gene/protein expression, whereas silencing Sig1R significantly decreased NRF2 protein levels and increased oxidative stress, although (+)-PTZ did not disrupt NRF2-KEAP1 binding. In vivo studies were conducted to investigate whether, in the absence of NRF2, activation of Sig1R rescues cones. (+)-PTZ was administered systemically for several weeks to rd10/nrf2+/+ and rd10/nrf2-/- mice. Through post-natal day 42, cone function was significant in rd10/nrf2+/+, but minimal in rd10/nrf2-/- mice as indicated by electroretinographic recordings using natural noise stimuli, optical coherence tomography and retinal histological analyses. Immunodetection of cones was limited in (+)-PTZ-treated rd10/nrf2-/-, though considerable in (+)-PTZ-treated rd10/nrf2+/+mice. The data suggest that Sig1R-mediated cone rescue requires NRF2 and provide evidence for a previously-unrecognized relationship between these proteins.

Erratum: Observation of D^{0} Meson Nuclear Modifications in Au+Au Collisions at sqrt[s_{NN}]=200 GeV [Phys. Rev. Lett. 113, 142301 (2014)]

This corrects the article DOI: 10.1103/PhysRevLett.113.142301.

IL-37 inhibits IL-4/IL-13-induced CCL11 production and lung eosinophilia in murine allergic asthma

BACKGROUND

IL-37 is emerging as an anti-inflammatory cytokine, particularly in innate inflammation. However, the role of IL-37 in Th2-mediated allergic lung inflammation remains uncertain. We sought to determine the role and the underlying mechanisms of IL-37 in the development of house dust mites (HDM)-induced murine asthma model.

METHODS

We examined the effect of IL-37 administration during the sensitization or challenge phase on Th2-mediated allergic asthma induced by inhaled HDM. Cellular source of CCL11 and distribution of IL-37 receptors, IL-18Rα and IL-1R8, were determined in HDM-exposed lungs. Finally, we examined the effect of IL-37 on CCL11 production and STAT6 activation in different primary lung structural cell types upon IL-4/IL-13 stimulation.

RESULTS

IL-37 had no effect on HDM sensitization, but when administrated during the challenge phase, significantly attenuated pulmonary eosinophilia, CCL11 production, and airway hyper-reactivity (AHR). Interestingly, IL-37 treatment had no significant effects on lung infiltrating T cells and Th2 cytokine production. Intranasal co-administration of CCL11 reversed the inhibiting effect of IL-37 on HDM-induced pulmonary eosinophilia and AHR. Furthermore, we demonstrated that CCL11 was primarily expressed by fibroblasts and airway smooth muscle cells (AMSC), while IL-37 receptors by tracheobronchial epithelial cells (TEC). In vitro study showed that IL-37 inhibited IL-4/IL-13-induced STAT6 activation and CCL11 production by fibroblasts and AMSC, which was dependent on its direct action on TEC. Moreover, cell contact was required for the inhibitory effect of IL-37-treated TEC.

CONCLUSIONS

IL-37 attenuates HDM-induced asthma, possibly by inhibiting IL-4/IL-13-induced CCL11 production by fibroblasts and AMSC via its direct act on TEC.

[Clinical application of negative pressure dressing in the full-thickness skin grafting]

Objective: To investigate the effect of different negative pressure of wound negative pressure dressing (NPD) on the survival of full-thickness skin grafts of patients. Methods: One hundred and eleven patients who need skin grafting, conforming to the inclusion criteria were hospitalized in our unit from August 2012 to March 2017, and their clinical data were retrospectively analyzed. Forty-seven patients hospitalized from August 2012 to October 2015 were assigned into traditional treatment group. Sixty-four patients hospitalized from November 2015 to March 2017 were divided into -9.975 kPa negative pressure treatment group (n=34) and -13.300 kPa negative pressure treatment group (n=30). Patients in traditional treatment group received conventional dressing after full-thickness skin grafting. Patients in -9.975 kPa and -13.300 kPa negative pressure treatment groups received -9.975 kPa and -13.300 kPa NPD based on traditional treatment after vacuum sealing, respectively. Dot necrosis area of skin grafts and erosion and escharosis of graft edges of patients in the three groups on post operation day 10 were observed. The percentage of dot necrosis area of skin grafts and occurrence rate of erosion and escharosis of skin graft edges were calculated, respectively. Data were processed with chi-square test, Fisher's exact test, and Kruskal-Wallis H test. Results: Percentages of dot necrosis area of skin grafts of patients in traditional treatment group and -9.975 kPa and -13.300 kPa negative pressure treatment groups were 17.81%, 3.20%, and 3.00%, respectively. Percentage of dot necrosis area of skin grafts of patients in traditional treatment group was significantly higher than that in -9.975 kPa and -13.300 kPa negative pressure treatment groups (Z=-5.770, -4.690, P<0.001). Percentages of dot necrosis area of skin grafts of patients in -9.975 kPa and-13.300 kPa groups were close (Z=-0.619, P>0.05). The occurrence rates of erosion and escharosis of skin graft edges of patients in traditional treatment group and -9.975 kPa and -13.300 kPa negative pressure treatment groups were 78.7% (37/47), 32.4 (11/34), and 36.7% (11/30), respectively. Erosion and escharosis of skin graft edges of patients in -9.975 kPa and -13.300 kPa negative pressure treatment groups were better than those in traditional treatment group (P<0.001). Erosion and escharosis of skin graft edges of patients in -9.975 kPa and -13.300 kPa negative pressure treatment groups were close (P>0.05). Conclusions: The use of -9.975 kPa and -13.300 kPa NPD in skin grafts after full-thickness skin grafting significantly diminishes the occurrence rates of dot necrosis area of skin grafts and erosion and escharosis of graft edges.

Exploiting coumarin-6 as ancillary ligands in 1,10-phenanthroline Ir(iii) complexes: generating triplet photosensitisers with high upconversion capabilities

A series of new Ir(iii) complexes incorporating 3-(2-benzothiazolyl)-7-(diethylamino)coumarin (coumarin 6) and ethynylpyrene (EP) functionalised 1,10-phenanthroline (phen) were developed. [Ir(iii)(coumarin 6)₂(3-EP-phen)](PF₆) (Ir-3) proved to be the most promising material in triplet photosensitising applications. Highly absorbing at λ = 485 nm (ε = 1.31 × 10⁵ M^-1 cm^-1), it exhibits high upconversion and singlet oxygen quantum yields (Φ_UC = 27.5%, Φ_Δ = 81.5%) and an exemplary upconversion capability (η = 3.60 × 10⁶ M^-1 cm^-1).

Mechanisms of sphingosine-1-phosphate-mediated vasoconstriction of rat afferent arterioles

AIM

Sphingosine-1-phosphate (S1P) influences resistance vessel function and is implicated in renal pathological processes. Previous studies revealed that S1P evoked potent vasoconstriction of the pre-glomerular microvasculature, but the underlying mechanisms remain incompletely defined. We postulated that S1P-mediated pre-glomerular microvascular vasoconstriction involves activation of voltage-dependent L-type calcium channels (L-VDCC) and the rho/rho kinase pathway.

METHODS

Afferent arteriolar reactivity was assessed in vitro using the blood-perfused rat juxtamedullary nephron preparation, and diameter was measured during exposure to physiological and pharmacological agents.

RESULTS

Exogenous S1P (10^-9 -10^-5 mol L^-1 ) evoked concentration-dependent vasoconstriction of afferent arterioles. Superfusion with nifedipine, a L-VDCC blocker, increased arteriolar diameter by 39 ± 18% of baseline and significantly attenuated the S1P-induced vasoconstriction. Superfusion with the rho kinase inhibitor, Y-27632, increased diameter by 60 ± 12% of baseline and also significantly blunted vasoconstriction by S1P. Combined nifedipine and Y-27632 treatment significantly inhibited S1P-induced vasoconstriction over the entire concentration range tested. In contrast, depletion of intracellular Ca²⁺ stores with the Ca²⁺ -ATPase inhibitors, thapsigargin or cyclopiazonic acid, did not alter the S1P-mediated vasoconstrictor profile. Scavenging reactive oxygen species (ROS) or inhibition of nicotinamide adenine dinucleotide phosphate oxidase activity significantly attenuated S1P-mediated vasoconstriction.

CONCLUSION

Exogenous S1P elicits potent vasoconstriction of rat afferent arterioles. These data also demonstrate that S1P-mediated pre-glomerular vasoconstriction involves activation of L-VDCC, the rho/rho kinase pathway and ROS. Mobilization of Ca²⁺ from intracellular stores is not required for S1P-mediated vasoconstriction. These studies reveal a potential role for S1P in the modulation of renal microvascular tone.

A dynamic monitoring approach for the surface morphology evolution measurement of plasma facing components by means of speckle interferometry

Plasma Facing Components (PFCs) in a magnetically confined fusion plasma device will be exposed to high heat load and particle fluxes, and it would cause PFCs' surface morphology to change due to material erosion and redeposition from plasma wall interactions. The state of PFCs' surface condition will seriously affect the performance of long-pulse or steady state plasma discharge in a tokamak; it will even constitute an enormous threat to the operation and the safety of fusion plasma devices. The PFCs' surface morphology evolution measurement could provide important information about PFCs' real-time status or damage situation and it would help to a better understanding of the plasma wall interaction process and mechanism. Meanwhile through monitoring the distribution of dust deposition in a tokamak and providing an upper limit on the amount of loose dust, the PFCs' surface morphology measurement could indirectly contribute to keep fusion operational limits and fusion device safety. Aiming at in situ dynamic monitoring PFCs' surface morphology evolution, a laboratory experimental platform DUT-SIEP (Dalian University of Technology-speckle interferometry experimental platform) based on the speckle interferometry technique has been constructed at Dalian University of Technology (DUT) in China. With directional specific designing and focusing on the real detection condition of EAST (Experimental Advanced Superconducting Tokamak), the DUT-SIEP could realize a variable measurement range, widely increased from 0.1 μm to 300 μm, with high spatial resolution (<1 mm) and ultra-high time resolution (<2 s for EAST measuring conditions). Three main components of the DUT-SIEP are all integrated and synchronized by a time schedule control and data acquisition terminal and coupled with a three-dimensional phase unwrapping algorithm, the surface morphology information of target samples can be obtained and reconstructed in real-time. A local surface morphology of the real divertor tiles adopted from EAST has been measured, and the feasibility and reliability of this new experimental platform have been demonstrated.