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1.
Microorganisms ; 12(6)2024 May 23.
Article in English | MEDLINE | ID: mdl-38930432

ABSTRACT

Traditional microbial diagnostic methods face many obstacles such as sample handling, culture difficulties, misidentification, and delays in determining susceptibility. The advent of artificial intelligence (AI) has markedly transformed microbial diagnostics with rapid and precise analyses. Nonetheless, ethical considerations accompany AI adoption, necessitating measures to uphold patient privacy, mitigate biases, and ensure data integrity. This review examines conventional diagnostic hurdles, stressing the significance of standardized procedures in sample processing. It underscores AI's significant impact, particularly through machine learning (ML), in microbial diagnostics. Recent progressions in AI, particularly ML methodologies, are explored, showcasing their influence on microbial categorization, comprehension of microorganism interactions, and augmentation of microscopy capabilities. This review furnishes a comprehensive evaluation of AI's utility in microbial diagnostics, addressing both advantages and challenges. A few case studies including SARS-CoV-2, malaria, and mycobacteria serve to illustrate AI's potential for swift and precise diagnosis. Utilization of convolutional neural networks (CNNs) in digital pathology, automated bacterial classification, and colony counting further underscores AI's versatility. Additionally, AI improves antimicrobial susceptibility assessment and contributes to disease surveillance, outbreak forecasting, and real-time monitoring. Despite a few limitations, integration of AI in diagnostic microbiology presents robust solutions, user-friendly algorithms, and comprehensive training, promising paradigm-shifting advancements in healthcare.

2.
Indian J Crit Care Med ; 27(12): 895-901, 2023 Dec.
Article in English | MEDLINE | ID: mdl-38074968

ABSTRACT

Introduction: Intracerebral hemorrhage (ICH) is a severe form of stroke with substantial morbidity and mortality worldwide. Despite its impact, research has often focused on ischemic strokes, making ICH an essential area to explore. Methods: A retrospective cohort study spanning 5 years was conducted in an Oman-based tertiary care teaching hospital's emergency room. Data from patients diagnosed with spontaneous ICH, confirmed by cranial CT scans, were analyzed. Ethical approval was obtained. Results: Among 163 emergency room (ER)-presented patients with ICH, 89 met the inclusion criteria. Most were male (69.66%), with hypertension (69/89) and diabetes mellitus (43/89) being common comorbidities. Hematoma size was a crucial predictor of poor outcomes, especially for larger hematomas (>60 cm³). Midline shift, intraventricular hemorrhages, elevated systolic and diastolic blood pressure, and low Glasgow Coma Scale (GCS) scores were significantly associated with unfavorable outcomes. However, variables such as age, gender, history of heart disease, hypertension, diabetes, and anticoagulant use did not show significant associations with disability outcomes. Favorable outcomes (mRS <3) were observed in 47.2% of patients, while 30.3% had a major disability (mRS 3-5), and 22.5% succumbed to their illness (mRS 6). Conclusion: This study enhances our understanding of ICH outcomes, highlighting the importance of hematoma size, midline shift, intraventricular hemorrhage, blood pressure control, and GCS scores in predicting disability. Future research could explore additional prognostic factors and interventions for ICH patients. How to cite this article: Al-Alawi AKA, Hazra D, Al-Hassani MJK, Al-Jamoudi ASA. Unveiling the Crystal Ball: Predictors of Adverse Outcomes in Intracerebral Hemorrhage Patients. Indian J Crit Care Med 2023;27(12):895-901.

3.
Arch Dermatol Res ; 310(3): 197-207, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29368135

ABSTRACT

The Stat6VT mouse model of atopic dermatitis (AD) is induced by T-cell-specific expression of a constitutively active form of the protein signal transducer and activator of transcription 6 (STAT6). Although AD-like lesions are known to develop in Stat6VT mice, this study was designed to determine if these mice develop acute and chronic phases of disease similar to humans. To address this, AD-like lesions from Stat6VT mice were harvested at two different timepoints relative to their onset. Lesions harvested within 1 week after development were defined as acute lesions, and those present for 1 month or more were defined as chronic lesions. Acute and chronic AD-like lesions from Stat6VT mice exhibited histologic findings and cytokine expression patterns similar to acute and chronic AD lesions in humans. Further analysis revealed increased levels of interleukin (IL)-33 transcripts in AD-like lesions compared to Stat6VT nonlesional and wild-type skin controls. Immunofluorescence also revealed increased numbers of IL-33+ keratinocytes in Stat6VT lesional skin and localized IL-33+ keratinocytes to a keratin 5+ subset. Furthermore, AD-like disease was more severe in IL-33-deficient Stat6VT mice compared to IL-33-sufficient Stat6VT mice. These studies suggest that Stat6VT mice can serve as a model of acute and chronic AD and that IL-33 may attenuate inflammation in this system.


Subject(s)
Dermatitis, Atopic/pathology , Interleukin-33/metabolism , Keratin-15/metabolism , Keratinocytes/metabolism , STAT6 Transcription Factor/metabolism , Animals , Disease Models, Animal , Inflammation/pathology , Interleukin-33/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Skin/pathology , Th1 Cells/immunology , Th2 Cells/immunology
4.
Cancer Res ; 74(23): 7069-78, 2014 Dec 01.
Article in English | MEDLINE | ID: mdl-25304264

ABSTRACT

Oxidative stress suppresses host immunity by generating oxidized lipid agonists of the platelet-activating factor receptor (PAF-R). Because many classical chemotherapeutic drugs induce reactive oxygen species (ROS), we investigated whether these drugs might subvert host immunity by activating PAF-R. Here, we show that PAF-R agonists are produced in melanoma cells by chemotherapy that is administered in vitro, in vivo, or in human subjects. Structural characterization of the PAF-R agonists induced revealed multiple oxidized glycerophosphocholines that are generated nonenzymatically. In a murine model of melanoma, chemotherapeutic administration could augment tumor growth by a PAF-R-dependent process that could be blocked by treatment with antioxidants or COX-2 inhibitors or by depletion of regulatory T cells. Our findings reveal how PAF-R agonists induced by chemotherapy treatment can promote treatment failure. Furthermore, they offer new insights into how to improve the efficacy of chemotherapy by blocking its heretofore unknown impact on PAF-R activation.


Subject(s)
Antineoplastic Agents/immunology , Antineoplastic Agents/pharmacology , Melanoma, Experimental/drug therapy , Melanoma, Experimental/immunology , Platelet Activating Factor/agonists , Animals , Antioxidants/pharmacology , Cell Line, Tumor , Cyclooxygenase 2 Inhibitors/immunology , Cyclooxygenase 2 Inhibitors/pharmacology , Female , Glycerylphosphorylcholine/immunology , Glycerylphosphorylcholine/metabolism , Humans , Mice , Mice, Inbred C57BL , Oxidative Stress/drug effects , Oxidative Stress/immunology , Platelet Activating Factor/immunology , Platelet Activating Factor/metabolism , Platelet Membrane Glycoproteins/immunology , Platelet Membrane Glycoproteins/metabolism , Reactive Oxygen Species/immunology , Reactive Oxygen Species/metabolism , Receptors, G-Protein-Coupled/immunology , Receptors, G-Protein-Coupled/metabolism , Signal Transduction/drug effects , Signal Transduction/immunology , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/immunology
5.
Saudi J Kidney Dis Transpl ; 23(4): 790-3, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22805393

ABSTRACT

The use of mycophenolate mofetil (MMF) is known to be associated with progressive multifocal leukoencephalopathy (PML). We report a case of PML in a patient receiving MMF, who showed improvement upon discontinuation of the drug. He was restarted on MMF, following which he went into coma. He showed prompt recovery upon stopping the drug again and made full recovery without any residual neurological deficit. This case is being reported to further highlight this neurological side-effect of MMF.


Subject(s)
Immunosuppressive Agents/adverse effects , Leukoencephalopathy, Progressive Multifocal/chemically induced , Mycophenolic Acid/analogs & derivatives , Adult , Humans , Kidney Failure, Chronic/surgery , Kidney Transplantation , Magnetic Resonance Imaging , Male , Mycophenolic Acid/adverse effects , Treatment Outcome
6.
J Biol Chem ; 287(12): 9311-21, 2012 Mar 16.
Article in English | MEDLINE | ID: mdl-22303003

ABSTRACT

To date, oxidized glycerophosphocholines (Ox-GPCs) with platelet-activating factor (PAF) activity produced non-enzymatically have not been definitively demonstrated to mediate any known disease processes. Here we provide evidence that these Ox-GPCs play a pivotal role in the photosensitivity associated with the deficiency of the DNA repair protein xeroderma pigmentosum type A (XPA). It should be noted that XPA-deficient cells are known to have decreased antioxidant defenses. These studies demonstrate that treatment of human XPA-deficient fibroblasts with the pro-oxidative stressor ultraviolet B (UVB) radiation resulted in increased reactive oxygen species and PAF receptor (PAF-R) agonistic activity in comparison with gene-corrected cells. The UVB irradiation-generated PAF-R agonists were inhibited by antioxidants. UVB irradiation of XPA-deficient (Xpa-/-) mice also resulted in increased PAF-R agonistic activity and skin inflammation in comparison with control mice. The increased UVB irradiation-mediated skin inflammation and TNF-α production in Xpa-/- mice were blocked by systemic antioxidants and by PAF-R antagonists. Structural characterization of PAF-R-stimulating activity in UVB-irradiated XPA-deficient fibroblasts using mass spectrometry revealed increased levels of sn-2 short-chain Ox-GPCs along with native PAF. These studies support a critical role for PAF-R agonistic Ox-GPCs in the pathophysiology of XPA photosensitivity.


Subject(s)
Platelet Activating Factor/agonists , Platelet Membrane Glycoproteins/agonists , Receptors, G-Protein-Coupled/agonists , Skin/radiation effects , Xeroderma Pigmentosum Group A Protein/metabolism , Xeroderma Pigmentosum/metabolism , Animals , Antioxidants/metabolism , Humans , Mice , Mice, Inbred C57BL , Mice, Knockout , Phosphorylcholine/metabolism , Platelet Activating Factor/metabolism , Platelet Membrane Glycoproteins/genetics , Platelet Membrane Glycoproteins/metabolism , Radiation Tolerance , Reactive Oxygen Species/metabolism , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Skin/metabolism , Tumor Necrosis Factor-alpha/metabolism , Ultraviolet Rays , Xeroderma Pigmentosum/genetics , Xeroderma Pigmentosum Group A Protein/genetics
7.
Arch Dermatol ; 147(6): 719-23, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21339416

ABSTRACT

BACKGROUND: In addition to recreational tanning bed use, UV radiation exposures are sometimes sought to self-treat skin conditions. The ability of tanning bed radiation exposure to trigger toxic epidermal necrolysis has not been reported. OBSERVATIONS: A young woman attempted to treat a self-limiting drug hypersensitivity reaction via tanning bed radiation exposure, which resulted in a systemic toxic epidermal necrolysis-like reaction. Studies with cultured keratinocytes and an epithelial cell line reveal that UV-A radiation can synergize with other stimuli such as phorbol esters or interleukin 1 to produce large amounts of tumor necrosis factor, providing a potential mechanism for this exaggerated reaction. CONCLUSION: In addition to inducing photodamage and skin cancer, tanning bed radiation exposure can trigger a toxic epidermal necrolysis-like reaction, possibly via the exaggerated production of keratinocyte cytokines such as tumor necrosis factor.


Subject(s)
Ibuprofen/adverse effects , Stevens-Johnson Syndrome/pathology , Sunbathing , Ultraviolet Rays/adverse effects , Cell Line , Disease Progression , Erythema/diagnosis , Erythema/etiology , Female , Humans , Immunoglobulins, Intravenous/therapeutic use , Keratinocytes/metabolism , Keratinocytes/radiation effects , Stevens-Johnson Syndrome/diagnosis , Stevens-Johnson Syndrome/drug therapy , Treatment Outcome , Tumor Necrosis Factors/biosynthesis , Young Adult
8.
Saudi J Kidney Dis Transpl ; 21(4): 646-51, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20587867

ABSTRACT

Successful pregnancy outcome is an uncommon occurrence in women requiring chronic dialysis treatment. We reviewed the course and outcome of 9 pregnancies occurred in women on chronic hemodialysis in our center from 1999-2007; 5 of them ended with delivery of alive newborns, 2 with fetal deaths in-utero, and 2 with abortions. The average age of patients was 34 years. The etiology of the original kidney disease was unknown in 44.4% of the cases, and only 22.2% of the patients maintained diuresis. Dialysis started in 8 cases before the diagnosis of pregnancy. The average gestational age at diagnosis was 14 weeks. We modified the prescription of dialysis in 4 patients by increasing the frequency of the dialysis sessions to 6 per week and in 3 by increasing the duration of each session to 6 hours. Anemia was present in all the cases; 3 patients received erythropoietin and 4 patients required transfusion. The pregnancy was com-plicated in 44% of the cases by a polyhydramnios. The average time at delivery was 33 weeks and it was achieved in 80% of pregnancies through vaginal route. The average weight of newborns was to 2380 g. We conclude that pregnancy in women on hemodialysis is possible. The success of pregnancy may be influenced by the residual diuresis and early diagnosis to improve the quality of dialysis by increasing the dialysis dose.


Subject(s)
Pregnancy Outcome , Renal Dialysis/methods , Acidosis/prevention & control , Blood Pressure , Diuresis/physiology , Female , Gestational Age , Hemoglobins/metabolism , Humans , Hypocalcemia/prevention & control , Live Birth , Pregnancy , Pregnancy Trimester, Second , Retrospective Studies
10.
J Allergy Clin Immunol ; 125(1): 146-52.e1-2, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19962742

ABSTRACT

BACKGROUND: Bacterial infection with Staphylococcus aureus is a known trigger for worsening of atopic dermatitis (AD); the exact mechanisms by which bacterial infection worsens dermatitis are unknown. OBJECTIVE: We sought to characterize the amounts of the biologically active bacterial lipoprotein lipoteichoic acid (LTA) in infected AD lesions. METHODS: Eighty-nine children with clinically impetiginized lesions of AD were enrolled in this study. A lesion was graded clinically by using the Eczema Area and Severity Index (EASI), wash fluid obtained from the lesion for quantitative bacterial culture, and measurement of LTA and cytokines. The staphylococcal isolate was tested for antibiotic susceptibilities. The patients were treated with a regimen that included topical corticosteroids and systemic antibiotics, and the lesion was reanalyzed after 2 weeks. RESULTS: S aureus was identified in 79 of 89 children enrolled in the study. The bacterial colony-forming unit (CFU) counts correlated with the EASI lesional score (P = .04). LTA levels as high as 9.8 mug/mL were measured in the wash fluid samples, and the amounts correlated with the lesional EASI scores (P = .01) and S aureus CFU (P < .001). Approximately 30% of clinically impetiginized AD lesions contained greater than 1 mug/mL LTA, amounts that exert effects on various cell types in vitro. Moreover, injection of skin tissue ex vivo with amounts of LTA found in AD lesions resulted in epidermal cytokine gene expression. CONCLUSION: Pharmacologic levels of LTA are found in many infected atopic dermatitis lesions.


Subject(s)
Dermatitis, Atopic , Lipopolysaccharides/analysis , Staphylococcal Skin Infections , Staphylococcus aureus , Teichoic Acids/analysis , Child , Child, Preschool , Colony Count, Microbial , Dermatitis, Atopic/immunology , Dermatitis, Atopic/microbiology , Dermatitis, Atopic/pathology , Eczema/immunology , Eczema/microbiology , Eczema/pathology , Humans , Infant , Interleukin-8/genetics , Interleukin-8/metabolism , Severity of Illness Index , Skin/chemistry , Skin/microbiology , Skin/pathology , Staphylococcal Skin Infections/immunology , Staphylococcal Skin Infections/microbiology , Staphylococcal Skin Infections/pathology , Staphylococcus aureus/isolation & purification , Staphylococcus aureus/pathogenicity , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism
11.
Photochem Photobiol ; 86(1): 231-5, 2010.
Article in English | MEDLINE | ID: mdl-19769579

ABSTRACT

Ultraviolet B radiation (UVB) is a potent stimulator of epidermal cytokine production which has been implicated in photoaggravated dermatoses. In addition to cytokines such as tumor necrosis factor-alpha (TNF-alpha), UVB generates bioactive lipids including platelet-activating factor (PAF). Our previous studies have demonstrated that UVB-mediated production of keratinocyte TNF-alpha is in part due to PAF. The current studies use a human PAF-receptor (PAF-R) negative epithelial cell line transduced with PAF-Rs and PAF-R-deficient mice to demonstrate that activation of the epidermal PAF-R along with UVB irradiation results in a synergistic production of TNF-alpha. It should be noted that PAF-R effects are mimicked by the protein kinase C (PKC) agonist phorbol myristic acetate, and are inhibited by pharmacological antagonists of the PKC gamma isoenzyme. These studies suggest that concomitant PAF-R activation and UVB irradiation results in a synergistic production of the cytokine TNF-alpha which is mediated in part via PKC. These studies provide a novel potential mechanism for photosensitivity responses.


Subject(s)
Platelet Membrane Glycoproteins/metabolism , Receptors, G-Protein-Coupled/metabolism , Tumor Necrosis Factor-alpha/biosynthesis , Ultraviolet Rays , Animals , Cytokines/biosynthesis , Humans , Mice , Protein Kinase C/metabolism , Skin/cytology , Skin/metabolism , Skin/radiation effects
12.
J Immunol ; 182(5): 2842-8, 2009 Mar 01.
Article in English | MEDLINE | ID: mdl-19234179

ABSTRACT

Recent studies have implicated the lipid mediator platelet-activating factor (PAF) in UVB-mediated systemic immunosuppression known to be a major cause for skin cancers. Previously, our group has demonstrated that UVB irradiation triggers the production of PAF and oxidized glycerophosphocholines that act as PAF-receptor (PAF-R) agonists. The present studies explored the mechanisms by which UVB generates PAF-R agonists. UVB irradiation of human epidermal KB cells resulted in both increased levels of reactive oxygen species (ROS) and PAF-R agonistic activity. Pretreatment of KB cells with antioxidants vitamin C and N-acetylcysteine or the pharmacological inhibitor PD168393 specific for the epidermal growth factor receptor all inhibited UVB-induced ROS as well as PAF-R agonists, yet had no effect on fMLP-mediated PAF-R agonist production. In addition, in vivo production of PAF-R agonists from UVB-irradiated mouse skin was blocked by both systemic vitamin C administration and topical PD168393 application. Moreover, both vitamin C and PD168393 abolished UVB-mediated but not the PAF-R agonist 1-hexadecyl-2-N-methylcarbamoyl glycerophosphocholine-mediated immunosuppression as measured by the inhibition of delayed type contact hypersensitivity to the chemical dinitrofluorobenzene. These studies suggest that UVB-induced systemic immunosuppression is due to epidermal growth factor receptor-mediated ROS which results in PAF-R agonist formation.


Subject(s)
ErbB Receptors/physiology , Platelet Activating Factor/metabolism , Platelet Membrane Glycoproteins/agonists , Platelet Membrane Glycoproteins/radiation effects , Reactive Oxygen Species/metabolism , Reactive Oxygen Species/radiation effects , Receptors, G-Protein-Coupled/agonists , Receptors, G-Protein-Coupled/radiation effects , Ultraviolet Rays , Animals , Dermatitis, Contact/etiology , Dermatitis, Contact/immunology , Dermatitis, Contact/metabolism , Epithelial Cells/immunology , Epithelial Cells/metabolism , Epithelial Cells/radiation effects , ErbB Receptors/radiation effects , Humans , Immunosuppression Therapy , KB Cells , Mice , Mice, Hairless , Mice, Inbred C57BL , Platelet Activating Factor/radiation effects , Platelet Membrane Glycoproteins/biosynthesis , Reactive Oxygen Species/pharmacology , Receptors, G-Protein-Coupled/biosynthesis , Skin/immunology , Skin/metabolism , Skin/radiation effects
13.
Nephrol Ther ; 5(1): 52-7, 2009 Feb.
Article in French | MEDLINE | ID: mdl-18675610

ABSTRACT

INTRODUCTION: Emphysematous pyelonephritis is a rare and severe form of acute pyelonephritis. It is defined as the presence of gas-producing bacteria in the kidney and in peri-nepheretic areas. We report a case of emphysematous pyelonephritis on a single kidney associated with urolithiasis. OBSERVATION: A 44-year-old woman, with a history of diabetes and chronic renal failure, presented with left renal colic, anuria, fever and worsening of general state. The diagnosis of emphysematous pyelonephritis was confirmed by CT scan. The treatment was based on antibiotheray, adapted to the renal function, insulinotherapy and urine drainage by a double J stent. The evolution was favourable. DISCUSSION: Emphysematous pyelonephritis is an uncommon infection, generally affecting female diabetic patients. CT scan is mandatory to confirm diagnosis. CONCLUSION: Even if it is rare, emphysematous pyelonephritis is associated with a high mortality in the absence of a rapid and effective treatment.


Subject(s)
Emphysema/complications , Pyelonephritis/complications , Adult , Emphysema/diagnostic imaging , Emphysema/drug therapy , Female , Humans , Nephrectomy , Pyelonephritis/diagnostic imaging , Pyelonephritis/drug therapy , Radiography
14.
J Invest Dermatol ; 128(2): 455-60, 2008 Feb.
Article in English | MEDLINE | ID: mdl-17928889

ABSTRACT

UVB radiation (UVB) is a known inducer of many biological changes in human skin, and triggers the production of glycerophosphocholines that act as platelet-activating factor (PAF) agonists. To gain a better insight into the role of the epidermal PAF receptor (PAF-R) in UVB-mediated gene expression, Affymetrix oligonucleotide microarrays were used to compare mRNA expression in the PAF-R-negative epithelial cell line KB-expressing PAF-Rs (KBP) with that in KB cells transduced with a vector control (KBM). Total RNA was isolated from KB cells 1 hour after treatment with a PAF-R agonist or UVB irradiation. Treatment of KBP with PAF agonist resulted in altered expression of 220 genes, including cytokines and growth factors. UVB irradiation of KB cells resulted in an increased expression of genes in both cell types. A panel of genes including cytokines CCL20 (MIP3alpha) and tumor necrosis factor-alpha (TNF-alpha) were upregulated selectively in KBP cells and are also selectively upregulated in response to PAF agonist. Consistent with these in vitro findings, UVB irradiation resulted in increased levels of epidermal CCL20 and TNF-alpha mRNA in wild-type over PAF-R-deficient mice in vivo. These studies provide evidence that the epidermal PAF-R can modulate UVB-mediated early gene expression.


Subject(s)
Epithelial Cells/physiology , Gene Expression Regulation/radiation effects , Platelet Membrane Glycoproteins/genetics , Platelet Membrane Glycoproteins/metabolism , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Ultraviolet Rays , Animals , Cell Line , Chemokine CCL20/genetics , Chemokine CCL20/metabolism , Epithelial Cells/cytology , Humans , Macrophage Inflammatory Proteins/genetics , Macrophage Inflammatory Proteins/metabolism , Mice , Mice, Inbred C57BL , Mice, Mutant Strains , Oligonucleotide Array Sequence Analysis , Tumor Necrosis Factor-alpha/genetics
15.
J Clin Invest ; 115(10): 2855-61, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16184199

ABSTRACT

Staphylococcus aureus infections are known triggers for skin inflammation and can modulate immune responses. The present studies used model systems consisting of platelet-activating factor receptor-positive and -negative (PAF-R-positive and -negative) cells and PAF-R-deficient mice to demonstrate that staphylococcal lipoteichoic acid (LTA), a constituent of Gram-positive bacteria cell walls, acts as a PAF-R agonist. We show that LTA stimulates an immediate intracellular Ca2+ flux only in PAF-R-positive cells. Intradermal injections of LTA and the PAF-R agonist 1-hexadecyl-2-N-methylcarbamoyl glycerophosphocholine (CPAF) induced cutaneous inflammation in wild-type but not PAF-R-deficient mice. Systemic exposure to LTA or CPAF inhibited delayed-type hypersensitivity (DTH) reactions to the chemical dinitrofluorobenzene only in PAF-R-expressing mice. The inhibition of DTH reactions was abrogated by the addition of neutralizing antibodies to IL-10. Finally, we measured levels of LTA that were adequate to stimulate PAF-R in vitro on the skin of subjects with infected atopic dermatitis. Based on these studies, we propose that LTA exerts immunomodulatory effects via the PAF-R through production of the Th2 cytokine IL-10. These findings show a novel mechanism by which staphylococcal infections can inhibit Th1 reactions and thus worsen Th2 skin diseases, such as atopic dermatitis.


Subject(s)
Drug Hypersensitivity/immunology , Hypersensitivity, Delayed/immunology , Lipopolysaccharides/administration & dosage , Platelet Activating Factor/analogs & derivatives , Platelet Membrane Glycoproteins/agonists , Receptors, G-Protein-Coupled/agonists , Staphylococcus aureus , Teichoic Acids/administration & dosage , Animals , Calcium/immunology , Cell Line , Dermatitis, Atopic/immunology , Dermatitis, Atopic/microbiology , Dermatitis, Atopic/pathology , Dinitrofluorobenzene/adverse effects , Drug Hypersensitivity/pathology , Drug Synergism , Humans , Hypersensitivity, Delayed/chemically induced , Hypersensitivity, Delayed/pathology , Inflammation/chemically induced , Inflammation/immunology , Inflammation/pathology , Interleukin-10/immunology , Lipopolysaccharides/chemistry , Mice , Mice, Knockout , Platelet Activating Factor/administration & dosage , Platelet Membrane Glycoproteins/deficiency , Platelet Membrane Glycoproteins/immunology , Receptors, G-Protein-Coupled/deficiency , Receptors, G-Protein-Coupled/immunology , Skin/immunology , Skin/pathology , Staphylococcal Infections/immunology , Staphylococcal Infections/pathology , Staphylococcus aureus/chemistry , Staphylococcus aureus/immunology , Teichoic Acids/chemistry , Th1 Cells/immunology , Th1 Cells/pathology , Th2 Cells/immunology , Th2 Cells/pathology
16.
J Immunol ; 172(10): 6330-5, 2004 May 15.
Article in English | MEDLINE | ID: mdl-15128823

ABSTRACT

In addition to their known cytotoxic effects, chemotherapeutic agents can trigger cytokine production in tumor cells. Moreover, many chemotherapeutic agents are potent pro-oxidative stressors. Although the lipid mediator platelet-activating factor (PAF) is synthesized in response to oxidative stress, and many epidermal carcinomas express PAF receptors (PAF-R) linked to cytokine production, it is not known whether PAF is involved in chemotherapeutic agent-induced cytokine production. These studies examined the role of the PAF system in chemotherapy-mediated cytokine production using a model system created by retroviral-mediated transduction of the PAF-R-negative human epidermal carcinoma cell line KB with the human PAF-R. The presence of the PAF-R in KB cells resulted in augmentation of the production of cytokines IL-8 and TNF-alpha induced by the chemotherapeutic agents etoposide and mitomycin C. These effects were specific for the PAF-R, as expression of the G protein-coupled receptor for fMLP did not affect chemotherapeutic agent-induced cytokine production. Moreover, ablation of the native PAF-R in the epithelial cell line HaCaT using an inducible antisense PAF-R strategy inhibited etoposide-induced cytokine production. Oxidative stress and the transcription factor NF-kappaB were found to be involved in this augmentative effect, because it was mimicked by the oxidant tert-butyl-hydroperoxide, which was blocked both by antioxidants and by inhibition of the NFkappaB pathway using a super-repressor IkappaBM mutant. These studies provide evidence for a novel pathway by which the epidermal PAF-R can augment chemotherapy-induced cytokine production through an NF-kappaB-dependent process.


Subject(s)
Adjuvants, Immunologic/physiology , Carcinoma, Squamous Cell/drug therapy , Carcinoma, Squamous Cell/immunology , Cytokines/biosynthesis , Platelet Membrane Glycoproteins/physiology , Receptors, G-Protein-Coupled/physiology , Adjuvants, Immunologic/biosynthesis , Adjuvants, Immunologic/genetics , Antineoplastic Agents/antagonists & inhibitors , Antineoplastic Agents/pharmacology , Antioxidants/pharmacology , Carcinoma, Squamous Cell/metabolism , Chromans/pharmacology , Cytokines/antagonists & inhibitors , Etoposide/antagonists & inhibitors , Etoposide/pharmacology , Humans , Interleukin-8/antagonists & inhibitors , Interleukin-8/biosynthesis , Interleukin-8/genetics , KB Cells , Mitomycin/pharmacology , NF-kappa B/physiology , Oxidative Stress/drug effects , Phospholipid Ethers/pharmacology , Platelet Membrane Glycoproteins/biosynthesis , Platelet Membrane Glycoproteins/deficiency , Platelet Membrane Glycoproteins/genetics , RNA, Messenger/antagonists & inhibitors , RNA, Messenger/biosynthesis , Receptors, G-Protein-Coupled/biosynthesis , Receptors, G-Protein-Coupled/deficiency , Receptors, G-Protein-Coupled/genetics , Signal Transduction/drug effects , Signal Transduction/immunology , Tetradecanoylphorbol Acetate/pharmacology , Transduction, Genetic
17.
J Biol Chem ; 278(19): 16614-21, 2003 May 09.
Article in English | MEDLINE | ID: mdl-12601006

ABSTRACT

Most chemotherapeutic agents exert their cytotoxic effects in part through the induction of apoptosis. In addition, many chemotherapeutic agents are potent pro-oxidative stressors. Although the lipid mediator platelet-activating factor (PAF) is synthesized in response to oxidative stress, and many epidermal carcinomas express PAF receptors, it is not known whether PAF is involved in chemotherapeutic agent-induced apoptosis. These studies examined the role of the PAF system in chemotherapy-mediated cytotoxicity using model systems created by retroviral mediated transduction of the PAF receptor-negative human epidermal carcinoma cell line KB with the human PAF receptor (PAF-R) and ablation of the endogenous PAF-R in the carcinoma cell line HaCaT with a retroviral mediated inducible antisense PAF-R vector. The presence of the PAF-R in these models resulted in an augmentation of apoptosis induced by chemotherapeutic agents etoposide and mitomycin C but not by tumor necrosis factor-related apoptosis-inducing ligand or by C(2) ceramide. Oxidative stress and the transcription factor nuclear factor kappaB (NF-kappaB) are found to be involved in this augmentative effect because it was blocked by antioxidants and inhibition of the NF-kappaB pathway using a super-repressor form of inhibitor B. These studies provide evidence for a novel pathway whereby the epidermal PAF-R can augment chemotherapy-induced apoptotic effects through an NF-kappaB-dependent process.


Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Neoplasms/drug therapy , Platelet Membrane Glycoproteins/physiology , Receptors, Cell Surface/physiology , Receptors, G-Protein-Coupled , Signal Transduction , Apoptosis/physiology , Humans , NF-kappa B/physiology , Neoplasms/pathology , Platelet Membrane Glycoproteins/drug effects , Receptors, Cell Surface/drug effects , Signal Transduction/drug effects , Signal Transduction/physiology , Tumor Cells, Cultured
18.
Lancet ; 360(9344): 1462-7, 2002 Nov 09.
Article in English | MEDLINE | ID: mdl-12433514

ABSTRACT

BACKGROUND: Arterial endothelial expression and raised serum concentrations of the soluble form of intercellular adhesion molecule-1 (ICAM-1) are implicated in development of transplant coronary artery disease. We investigated whether C-reactive protein, known to stimulate ICAM-1, was associated with increased ICAM-1 concentration and subsequent development of coronary artery disease. METHODS: With sandwich ELISAs, we measured C-reactive protein and soluble ICAM-1 in serial serum samples obtained during the first 3 months after transplantation in 109 heart-transplant patients. Matching endomyocardial biopsy samples were screened immunohistochemically for arterial endothelial ICAM-1. Serial coronary angiograms were assessed for development, severity, and progression of coronary artery disease. FINDINGS: We showed a significant correlation (p=0.001) between raised concentrations of C-reactive protein and arterial endothelial ICAM-1 expression in endomyocardial biopsy samples. We also noted a significant relation between C-reactive protein and soluble ICAM-1 concentrations soon after transplantation (p=0.003). Early raised C-reactive protein concentrations were associated with development (p=0.004), increased severity (p=0.02), and enhanced rate of progression (p=0.01) of coronary artery disease, and with heightened frequency of ischaemic events (p=0.049) and graft failure (p=0.04). INTERPRETATION: C-reactive protein concentration can be used to identify heart-transplant patients at increased risk of coronary artery disease and graft failure. Treatments directed at reduction of C-reactive protein concentration could improve patients' outcome.


Subject(s)
C-Reactive Protein/metabolism , Coronary Artery Disease/etiology , Endothelium, Vascular/metabolism , Heart Transplantation/immunology , Intercellular Adhesion Molecule-1/biosynthesis , Biopsy , Coronary Angiography , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/physiopathology , Female , Graft Survival , Heart Transplantation/diagnostic imaging , Heart Transplantation/pathology , Humans , Intercellular Adhesion Molecule-1/metabolism , Male , Middle Aged , Myocardial Ischemia , Myocardium/metabolism , Myocardium/pathology , Proportional Hazards Models , Prospective Studies , Survival Analysis
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