Enhancing tumour content and tumour cell count using microdissection contributes to higher detection rate of genetic mutations by next-generation sequencers

Background

Next-generation sequencing (NGS) analysis is becoming indispensable for the treatment of advanced lung cancer. NGS analysis requires a large number of cancer cell-containing tissues; however, it is often difficult for small biopsies to obtain the required quantities. In microdissection, only the tumour parts of a tissue specimen are obtained, which thereby increases the tumour content and tumour cell count of the tissue specimen. In this study, we investigated the extent to which the detection rate of genetic mutations changes by increasing the tumour content using microdissection.

Patients and methods

This is a retrospective study. In the genetic panel test using the Oncomine Dx Target Test (ODxTT), participants were divided into two groups: before (group A; April 2021-March 2022) and after (group B; April 2022-December 2022) the introduction of microdissection. The submission criteria for ODxTT were tumour content and tumour cell count >30 % and >2000 in group A, and >40 % and >5000 in group B, respectively. We compared the rate of genetic mutations detected using ODxTT between the two groups.

Results

This study included 214 consecutive ODxTT cases between April 2021 and December 2022. In group A (n = 112), 65 cases were adenocarcinoma, 84 involved lung tissue, and 64 underwent bronchoscopic sampling, whereas in group B (n = 102), 55 cases were adenocarcinoma, 91 cases involved lung tissue, and 79 cases underwent bronchoscopic sampling. Furthermore, genetic mutations were detected in 39 of 112 cases (35 %) in group A and 59 of 102 cases (58 %) in group B, which was statistically higher in group B (P = 0.0006). Genetic mutations were detected in 45 of 55 adenocarcinoma cases in group B. The genetic mutations detected in epidermal growth factor rescepor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS), and mesenchymal epithelial transition (MET) were higher in group B.

Conclusion

Increasing the number of tumour cells and tumour content can enhance the detection rate of genetic mutations using ODxTT.

Osteoblastic bone reaction in non-small cell lung cancer harboring epidermal growth factor receptor mutation treated with osimertinib

BACKGROUND

Osteoblastic bone reaction (OBR) refers to an increase in bone density at the site of bone metastasis or the appearance of new sclerotic bone lesions after anticancer treatment. OBR can be misunderstood as disease progression. In this study, we aimed to investigate the prevalence and details of OBR and its association with clinical outcomes in patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) treated with osimertinib.

METHODS

This was a single-center, retrospective cohort study. We reviewed patients who were diagnosed with EGFR-mutant NSCLC with bone metastasis and received osimertinib as a first-line treatment between February 2018 and October 2022. The OBR was evaluated by comparing baseline computed tomography (CT) scans with the first CT scan after treatment initiation.

RESULTS

A total of 45 patients were included in this study. Thirty-seven patients (82%) developed OBR. OBR developed in 94% (n = 16) of patients with sclerotic bone lesions (n = 17) at baseline. Similarly, OBR developed in lytic and mixed bone lesions in 76% and 82% of patients with lytic and mixed lesions, respectively. Progression-free survival (PFS) did not differ significantly between patients with (OBR group) and without OBR (non-OBR group) (median PFS, 24 months vs. 17 months; hazard ratio (HR), 0.62; 95% CI, 0.24-1.6; p = 0.31). In univariate analysis, the OBR group showed a trend toward longer skeletal-related events-free survival (SRE-FS) than the non-OBR group (median SRE-FS, 26 months vs. 12 months; HR, 0.53; 95% CI, 0.21-1.33; p = 0.16). Multivariate analysis showed OBR was a significant independent predictor of SRE-FS (HR, 0.35; 95% CI, 0.13-0.92; p = 0.034).

CONCLUSIONS

OBR developed in most patients with NSCLC and bone metastasis who received osimertinib treatment. The increased incidence of OBR in patients with EGFR-mutant NSCLC with bone metastasis treated with osimertinib should not be confused with disease progression, and treatment decisions should be made carefully.

Elevation of serum lactate dehydrogenase during methylprednisolone pulse therapy as a predictor of high mortality in acute respiratory failure: A single-center, retrospective study

Background

Corticosteroids are common treatments in certain diseases that cause acute respiratory failure (ARF) and are sometimes administered empirically for patients with critical ARF. Associations between changes in clinical parameters following initiation of steroid pulse therapy and mortality in patients with ARF have not been previously investigated.

Methods

This was a single-center and retrospective cohort study. Parameters on the day of methylprednisolone pulse therapy initiation (day 1) and the day following the end of methylprednisolone therapy (day 4) in patients who were admitted because of ARF and underwent methylprednisolone pulse therapy between October 2008 and July 2021 were reviewed.

Results

A total of 98 patients were included in our analysis, and 45 (46%) died at our hospital. Change in lactate dehydrogenase (LDH) from day 1 to day 4 (ΔLDH) was significantly higher in the in-hospital death group than in the survival group (-68 IU/L in the survival group versus 46 IU/L in the in-hospital death group, p < 0.01). Multivariate logistic analyses showed that age >75 years old (odds ratio (OR), 3.88; 95% confidence interval (CI), 1.38-10.9; p < 0.01), previously diagnosed interstitial lung disease (OR, 3.43; 95% CI, 1.10-10.7; p = 0.03), ΔLDH > 0 (OR, 6.47; 95% CI, 2.30-18.2; p < 0.01), and ΔSequential Organ Failure Assessment score > 0 (OR, 3.06; 95% CI, 1.10-8.51; p = 0.03) were significantly associated with in-hospital mortality.

Conclusions

This study showed that elevation of serum LDH level during methylprednisolone pulse therapy was a predictive factor for high in-hospital mortality in patients with ARF.

Rituximab for the Treatment of Anti-glomerular Basement Membrane Disease with Isolated Diffuse Alveolar Hemorrhage

Anti-glomerular basement membrane (GBM) disease with isolated diffuse alveolar hemorrhage (DAH) is rare. We herein report a 91-year-old man admitted with hypoxia and diagnosed with anti-GBM disease with DAH based on positive bronchoalveolar lavage and serum antibody test results. There was no renal involvement. Although remission was achieved using glucocorticoids and plasmapheresis, the patient experienced DAH relapse one week after the last plasmapheresis. Rituximab 375 mg/m2 was administered 4 times weekly; thereafter, DAH relapse was not observed, and the glucocorticoid dosage was tapered. Rituximab was thus effective in treating anti-GBM disease with isolated DAH in an extremely elderly patient.

Possible False Results With cobas® EGFR Mutation Test v2 and Oncomine Dx Target Test for EGFR Mutation

BACKGROUND/AIM

Disparities in the results of next-generation sequencing-based multiplex gene panel tests and those of single-gene tests when detecting epidermal growth factor receptor (EGFR) mutations in non-small-cell lung cancer (NSCLC) have been reported. However, the possible underlying causes have not been investigated. The aim of this study was to explore the possibilities and causes of false results obtained using cobas^® EGFR Mutation Test v2 (cobas^® EGFR) and Oncomine Dx Target Test (ODxTT).

PATIENTS AND METHODS

The data of patients with NSCLC who underwent gene assessment using both cobas^® EGFR and ODxTT between April 2021 and May 2022 were retrospectively reviewed. Disparate results of EGFR mutation analyses were then reviewed.

RESULTS

One hundred and sixteen patients were included in the analysis. The results of six samples were inconsistent. In four samples, exon 20 insertion mutations were detected using cobas^® EGFR, but not identified using ODxTT. A fragment analysis was performed on three of the four samples, and all showed negative results for exon 20 insertion. Furthermore, one false negative result was obtained in the ODxTT for both exon 19 deletion and L858R mutations. For exon 19 deletion mutation, a single nucleotide variant from adenine to thymine was identified close to the mutation site.

CONCLUSION

False positives for exon 20 insertion may occur when using cobas^® EGFR, and false negatives for exon 19 deletion and L858R mutations may occur when using ODxTT.

Right-sided vocal cord paralysis following stereotactic body radiation therapy for non-small-cell lung cancer: A case report

Vocal code paralysis (VCP) is a rare complication of stereotactic body radiation therapy (SBRT). In most previously reported cases of VCP after SBRT, VCP was left-sided because of anatomic vulnerability. Here, we report a case of right-sided VCP following SBRT for non-small-cell lung cancer. The patient was an 81-year-old man who underwent SBRT for synchronous lung cancer of the right upper and inferior lobes. He subsequently developed radiation pneumonitis and received corticosteroids. Lung contraction persisted, and the mediastinum shifted to the right because of lung volume reduction. After corticosteroids discontinuation, the patient developed hoarseness and voice weakness. An endoscopic test showed right-sided VCP. Imaging examinations did not reveal new lesions, including lung cancer recurrence. Therefore, we diagnosed the patient with SBRT-associated VCP and speculated that the injury to the right vagal nerve and recurrent laryngeal nerve resulted from mechanical traction due to intense lung contraction, which might have induced VCP. We should be alert to VCP following SBRT, even if the target lesions are right-sided.

Mortality and 30-day readmission rate following leadless pacemaker implantation: insights from the Nationwide Readmissions Database

Background

Clinical trials and registry data showed encouraging outcomes for leadless pacemaker (LP) implantation. However, reports of patient characteristics, trends, and clinical outcomes in a real-world population are limited.

Purpose

To provide real-world evidence of the rates, trends, and patient characteristics associated with in-hospital complications and 30-days readmission after LP implantations.

Methods

Using the all-payer, nationally representative Nationwide Readmissions Database between 2017 and 2019, we analyzed leadless or conventional pacemaker implantations. The national trends of in-hospital mortality, in-hospital complication rates and 30-day readmission rates after pacemaker implantation and their national trends were analyzed. Mixed-effects multivariable logistic regression analysis was performed to identify factors associated with in-hospital death and 30-days readmission in LP patients.

Results

A total of 137,732 admissions (age: 78 [70–85], 5,986 LP implantations) were analyzed (Figure 1). The in-hospital mortality, overall in-hospital complication rate, and 30-days readmission rates after LP implantations were 5.0%, 16%, and 16%, respectively. In LP recipients, the national estimate of in-hospital mortality declined from 10.9% in the second quarter of 2017 to 4.3% in the fourth quarter of 2019 (P&lt;0.001) (Figure 2a). Furthermore, the national estimate of overall complication rate declined from 20.6% in the second quarter of 2017 to 13.0% in the fourth quarter of 2019 (P&lt;0.001) (Figure 2b). Conversely, non-elective 30-day readmission rate did not show any increasing or decreasing trends in LP recipients (P=0.74) (Figure 2c). In LP recipients, female sex (odds ratio [OR] 1.42, 95% confidence interval [CI] 1.04–1.93), history of heart failure (OR 2.02, 95% CI 1.46–2.79), and first quartile annual pacemaker implantation hospital volume (OR 2.49, 95% CI 1.56–3.97, fourth quartile annual pacemaker implantation hospital volume used as a reference standard) were factors associated with in-hospital death.

Conclusions

Analysis of the nationally representative claims database in the US showed in-hospital mortality, complication rates, and non-elective 30-day readmission rate of 5.0%, 16%, and 16% respectively, for LP implantation performed during hospitalization. Although in-hospital mortality and complication rates showed a decreasing trend over time, ongoing surveillance is needed for the safety of LP implantation.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Intramural research fund (21-6-9)for cardiovascular diseases of national cerebral and cardiovascular center.

The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force

Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection.

Genetic mechanisms influencing COVID-19 susceptibility are not well understood. Here, the authors analyzed whole blood RNA-seq data of 465 Japanese individuals with COVID-19, highlighting thousands of fine-mapped variants affecting expression and splicing of genes, as well as the presence of COVID-19 severity-interaction eQTLs.

High neutrophils and low lymphocytes percentages in bronchoalveolar lavage fluid are prognostic factors of higher in-hospital mortality in diffuse alveolar hemorrhage

BACKGROUND

Diffuse alveolar hemorrhage (DAH) is a syndrome resulting from bleeding in the microcirculation of the lung, with a poor prognosis. The study aim was to identify prognostic factors of DAH, especially bronchoalveolar lavage fluids (BALF) cell pattern.

METHODS

We conducted a single-center retrospective cohort study of patients diagnosed as having DAH and hospitalized at our hospital between October 2008 and July 2020. We performed univariate logistic regressions to identify variables associated with in-hospital death.

RESULTS

Sixty-eight patients were included in our analysis. In-hospital mortality was 26.5%. Variables associated with in-hospital death were neutrophils percentage in BALF ≥ 44.5% [Odds Ratio (OR) 16.0, 95% confidence interval (CI) 4.33-58.9)], lymphocytes percentage in BALF < 14% (OR 7.44, 95% CI 2.11-26.2), idiopathic DAH (OR 0.31, 95% CI 0.10-0.95), oxygen flow ≥ 4L/min (OR 3.90, 95% CI 1.20-12.6), and estimated glomerular filtration rate < 60 mL/min (OR 5.00, 95%CI 1.29-19.4).

CONCLUSIONS

High neutrophils and low lymphocytes percentages in BALF were associated with poor prognosis.

Secondary organizing pneumonia after coronavirus disease 2019: Two cases

Coronavirus disease 2019 (COVID-19) has been reported to induce persistent symptoms even after an acute phase. However, the pathophysiology and treatment of this condition have been unclear. We report two patients who recovered from COVID-19, but presented persistent respiratory symptoms. Their respiratory conditions deteriorated, and computed tomography showed remaining ground glass opacities and consolidations. The pathological findings of transbronchial lung biopsy corresponded to organizing pneumonia. We diagnosed them with secondary organizing pneumonia after COVID-19. Subsequently, we administered systemic corticosteroids. Their symptoms, oxygenations, radiologic findings, and pulmonary functions rapidly improved after the treatment of corticosteroids. The two cases showed that secondary organizing pneumonia may be a cause of persistent respiratory failure after COVID-19. In this condition, corticosteroids may be effective.

Pembrolizumab-Induced Delayed-Onset Hepatitis

Hepatitis is one of the serious immune-related adverse events (irAEs). However, delayed-onset hepatitis induced by immune-checkpoint inhibitors (ICIs) is rare, and the histopathological features remain to be clarified. A 65-year-old woman with advanced lung adenocarcinoma in the right upper lobe (cT4N3M1c, c-stage IVB) received four courses of pembrolizumab. Her hepatic and biliary tract enzyme levels started increasing 2 months after the final administration of pembrolizumab, and the elevated levels of these enzymes prolonged. Liver biopsy revealed panlobular infiltration of inflammatory cells, and most of the infiltrating inflammatory cells were lymphocytes; however, there were a small number of neutrophils, eosinophils, and plasma cells. There was no confluent necrosis. Furthermore, immunohistochemical analyses proved that infiltrating lymphocytes were predominantly CD3-positive (CD3+) and CD8+, and few CD20+ and CD4+ lymphocytes were observed. Based on these findings, she was diagnosed with a case of hepatitis as an irAE. Administration of prednisolone (0.5 mg/kg/day) as well as the addition of azathioprine failed to suppress the deterioration. However, an increase in the dose of prednisolone (up to 1 mg/kg/day) enabled us to control hepatitis. This case showed that hepatitis can occur even after discontinuation of ICIs, and that liver biopsy may be useful in the diagnosis. Clinicians should not hesitate to perform liver biopsy for confirmation of the diagnosis.

Durvalumab-Induced Diffuse Alveolar Hemorrhage: An Autopsy Case Report

Durvalumab, a programmed cell death ligand 1 inhibitor, induces various immune-related adverse events (irAEs), including lung injury. However, diffuse alveolar hemorrhage (DAH) is a rare type of lung injury due to immune checkpoint inhibitors. A 76-year-old man with c-stage IIIA squamous cell carcinoma of the lung received maintenance durvalumab therapy after chemoradiotherapy. He developed dyspnea and malaise after 11 cycles of durvalumab. Chest computed tomography showed rapidly spreading bilateral ground-glass opacity in the lungs. We diagnosed DAH by hemosiderin-laden macrophages in bloody bronchoalveolar lavage fluid. Despite mechanical ventilation, steroids, and cyclophosphamide, he died of respiratory failure. The autopsy revealed that fresh and old bleeding areas coexisted, and neither pulmonary vasculitis nor diffuse alveolar damage was detected microscopically. Furthermore, CD3+ and CD8+ lymphocytes were observed in the lung interstitium, whereas CD20+ and CD4+ lymphocytes were scarcely detected. We report the first case of durvalumab-induced DAH. We should be alert to irAEs with DAH as a potential differential diagnosis of lung injury during durvalumab treatment.

Lactosylceramide is essential for the osteoclastogenesis mediated by macrophage-colony-stimulating factor and receptor activator of nuclear factor-kappa B ligand

Glycosphingolipids and their metabolites play important roles in a variety of biological processes. Several signal molecules are localized in a glycolipid-enriched microdomain on the cell surface, and their signals are regulated by the glycolipid composition. However, the function of glycolipids in osteoclastogenesis has not been clearly understood. We found that D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), a glucosylceramide synthase inhibitor, completely inhibits the osteoclast formation induced by macrophage-colony-stimulating factor and receptor activator of nuclear factor-kappa B ligand (RANKL) in a dose-dependent manner. Expression of RANK, the receptor of RANKL, induced by macrophage colony-stimulating factor, was reduced markedly in D-PDMP-treated cells. d-PDMP also inhibited the phosphorylation of the inhibitor of nuclear factor-kappa B and extracellular signal-regulated kinase 1/2 induced by RANKL. In several experiments with the addition of glycolipids to D-PDMP-treated purified bone marrow cells, lactosylceramide (LacCer) strongly affected the differentiation into tartrate-resistant acid phosphatase mononucleated cells, but not positive multinucleated cells. GM3 and GM1 also recovered, but less effectively compared with LacCer. Moreover, exogenous LacCer recovered the reduced expression of RANK and the phosphorylation of inhibitor of NF-kappa B and extracellular signal-regulated kinase 1/2 after stimulation by RANKL at the same level of cells without D-PDMP treatment. Our data suggest that glycosphingolipids, especially LacCer, are necessary for the initiation step of RANKL-induced osteoclastogenesis.

Force-induced osteoclast apoptosis in vivo is accompanied by elevation in transforming growth factor beta and osteoprotegerin expression

The mechanism controlling the disappearance of osteoclasts from bone surfaces after bone resorption in vivo is largely unknown. This is because there is no suitable experimental system to trace the final fate of osteoclasts. Here, we used an experimental model of tooth movement in rats to show that preexisting osteoclasts disappeared from the bone surface through apoptosis during a force-induced rapid shift from bone resorption to formation. On the distal alveolar bone surface of the maxillary molar in growing rats, many mature osteoclasts were present. When light tensional force was applied to the bone surface through an orthodontic appliance, these preexisting osteoclasts gradually disappeared. One day after the application of force, about 24% of the osteoclasts exhibited apoptotic morphology and the proportion of apoptotic cells was increased to 41% by day 2, then decreased afterward. These changes were undetectable on the control distal alveolar bone surface, which is free from tensional force. As shown by in situ hybridization, a marked increase in transforming growth factor beta1 (TGF-beta1) and osteoprotegerin (OPG) messenger RNA (mRNA) was observed in the stretched cells on the tensioned distal bone surface, simultaneously with the loss of osteoclasts. Both of these factors are known to have a negative effect on osteoclast recruitment and survival. As early as 2 days after force application, some of these stretched cells were identified as cuboidal osteoblasts showing intense signals for both factors. Our data suggest there may be a sequential link in tensional force applied on the bone lining cells, up-regulation of TGF-beta1/OPG, and disappearance of osteoclasts.

A common downstream signaling activity of osteoclast survival factors that prevent nitric oxide-promoted osteoclast apoptosis

Treatment with NO-releaser NOC18 significantly promoted apoptosis in murine osteoclast-like cells, with a transient increase in caspase-3-like protease activity. In contrast, the apoptosis was protected against by caspase inhibitors, most efficiently with the broadly acting caspase specific inhibitor z-Asp-CH2-DCB, indicating involvement of multiple caspases in progression of the apoptosis. Among osteoclast survival factors examined, calcitonin completely protected against morphologically defined-apoptosis and the increase of caspase-3-like protease activity. The effect of calcitonin was mimicked by treatment of cells with (Bu)2cAMP and forskolin, and abolished by protein kinase-A inhibitor H-89. Independently from the PKA activation, colony stimulating factor-1, interleukin-1beta and the receptor activator of NF-kappaB ligand also protected against the apoptosis but were less effective than calcitonin. All survival factors investigated inhibited conversion of procaspases-3 and -9 to their mature forms in the cells. Thus, downstream antiapoptotic signaling activity from each factor overlapped in inhibition of caspases. However, how this was attained seemed to be different from each other. Typically, only colony stimulating factor-1 up-regulated expression of endogenous caspase inhibitor protein, X-linked inhibitor of apoptosis (XIAP), in the osteoclast-like cells.

Fluorescence microscopic demonstration of cathepsin K activity as the major lysosomal cysteine proteinase in osteoclasts

The enzyme activity of lysosomal cysteine proteinases in vital rabbit osteoclasts and mouse osteoclast-like cells was visualized with Z-Leu-Arg-4-methoxy-beta-naphthylamide (Z-LR-MNA) as the enzyme substrate. The MNA liberated by proteolysis forms a fluorescent insoluble Schiff-base product in the presence of 5-nitrosalicylaldehyde. Many small fluorescent particles, endproducts of the Z-LR-MNA hydrolysis, were observed in proximity to the bone surface underneath the actively resorbing osteoclasts, as well as in the cytoplasm. The Z-LR-MNA hydrolase activity was markedly diminished by bafilomycin A1 and chloroquine treatment. Moreover, the activity was completely inhibited by cysteine proteinase inhibitors such as leupeptin and E-64d, but not by other classes of proteinase inhibitors. About 60% of the hydrolase activity in mouse osteoclast-like cells was immunoabsorbed by anti-cathepsin K antibody-coupled Sepharose CL-4B beads, and about 10% of the activity was absorbed with the anti-cathepsin L antibody-coupled beads. Thus, the majority of the Z-LR-MNA hydrolase activity in osteoclasts was derived from cathepsin K. In contrast, using the same substrate in the assay, no detectable cathepsin K activity was observed in mouse peritoneal macrophages. The abundant cathepsin K activity in osteoclasts would therefore indicate a significant role of this enzyme in bone matrix degradation.

[Management of personnel exposure data with a personal computer]

This paper describes a software package that manages dosimeter inventory and exposure data with a personal computer. The computer, connected with the access control system, deals with both records of the film badge (FB) supply to workers and the ordering of new FB for a company, processes exposure data and produces reports. The software not only ensures accurate reports but also significantly reduces the tedious labour involved in managing the control system.

Inhibition of in vitro neutrophil responses to chemotactic factors by piroxicam

The effect of piroxicam on polymorphonuclear neutrophils (PMN) functions induced by several stimuli was evaluated in vitro. Preincubation of rabbit or human PMN with piroxicam inhibited the cellular responses elicited by N-formyl-methionyl-leucyl-phenylalanine (FMLP) such as superoxide anion (O2-) generation, granule enzyme release and chemotaxis. The effectiveness of piroxicam on each response was superior to those of indomethacin and ibuprofen. Also when either concanavalin A, zymosan-treated serum or ionophore A23187 was used as stimuli, piroxicam inhibited O2- generation of PMN. The inhibitory effect of piroxicam on FMLP-induced O2- generation was dependent on the concentration of stimuli and was reversed by increasing the extracellular calcium concentration. In addition, piroxicam had no effect on the activity of a chymotrypsin-like esterase, N-acetyl-phenylalanine-beta-naphthyl esterase, isolated from rabbit PMN. These results suggest that at least some of the anti-inflammatory effects of piroxicam may be mediated by affecting PMN functions, and the inhibition of O2- generation of PMN by piroxicam may be related to its capacity to modulate the association of calcium with these cells.

[Action of piroxicam on allergic inflammation]

Effects of piroxicam on allergic inflammation were investigated with allergic air pouch inflammation and antigen-induced arthritis in rats. In allergic air pouch inflammation, piroxicam exerted a dose-dependent inhibition (1-10 mg/kg, p.o.) of the exudate production, the migration of leukocytes and the release of lysosomal enzyme into the exudate; and its potency was superior to that of indomethacin and equivalent to that observed with prednisolone. In contrast with this, the suppressive effect of piroxicam on non-allergic air pouch inflammation was as weak as indomethacin. Prednisolone showed a similar effect on both types of air pouch inflammation. In antigen-induced arthritis, piroxicam showed a dose-dependent (0.3-3 mg/kg, p.o.) inhibitory effect on knee joint swelling and an improving action on the functional disorder of the inflamed joint. On this model, piroxicam was 3 to 4 times more active than both indomethacin and prednisolone. In non-allergic joint inflammation induced with croton oil in rats, however, the anti-inflammatory potency of piroxicam was almost equal to those of indomethacin and prednisolone. Piroxicam showed more potent inhibition than indomethacin on heterologous passive cutaneous anaphylaxis in rats, but showed only a slight inhibition on the increased vascular permeability caused by histamine and bradykinin. Piroxicam had no influence upon the plaque-forming cell response and the delayed hypersensitivity reaction in mice; furthermore, the hemolytic activity of complement in guinea-pig serum was scarcely affected by piroxicam in vitro. These results indicate that piroxicam possesses prominent efficiency on allergic inflammation and may function on several activities of inflammatory cells.

A possible role of arachidonate metabolism in allergic air pouch inflammation in rats. Anti-inflammatory effect of indomethacin and dexamethasone and the level of prostaglandin E2 in the exudate

The effect of indomethacin and dexamethasone on an allergic inflammation in rats, a novel model of allergic inflammation of an air pouch type, was examined. Indomethacin and dexamethasone exerted a dose-dependent inhibition of both the accumulation of inflammatory exudate and the migration of leukocytes into the exudate. And although prostaglandin E2 levels in the exudate were lowered to the same extent by treatment with indomethacin and dexamethasone, inhibition of both exudate accumulation and and leukocyte migration was more pronounced after treatment with dexamethasone. The difference in the effectiveness of indomethacin and dexamethasone in terms of inhibition of arachidonate metabolism in the allergic air pouch inflammation are discussed.