Spin-orbit torque switching of an antiferromagnetic metallic heterostructure

The ability to represent information using an antiferromagnetic material is attractive for future antiferromagnetic spintronic devices. Previous studies have focussed on the utilization of antiferromagnetic materials with biaxial magnetic anisotropy for electrical manipulation. A practical realization of these antiferromagnetic devices is limited by the requirement of material-specific constraints. Here, we demonstrate current-induced switching in a polycrystalline PtMn/Pt metallic heterostructure. A comparison of electrical transport measurements in PtMn with and without the Pt layer, corroborated by x-ray imaging, reveals reversible switching of the thermally-stable antiferromagnetic Néel vector by spin-orbit torques. The presented results demonstrate the potential of polycrystalline metals for antiferromagnetic spintronics.

Comparing the 1997 update of the 1982 American College of Rheumatology (ACR-97) and the 2012 Systemic Lupus International Collaborating Clinics (SLICC-12) criteria for systemic lupus erythematosus (SLE) classification: which enables earlier classification of SLE in an urban Asian population?

Objective

We compared the 1997 update of the 1982 American College of Rheumatology (ACR-97) and the 2012 Systemic Lupus International Collaborating Clinics (SLICC-12) criteria, for earlier classification of systemic lupus erythematosus (SLE) in a multiethnic urban Asian SLE population.

Methods

Patients from a retrospective, nested case-control study of the influence of lupus nephritis on mortality in SLE were studied. For each patient, dates of first manifestations of each criteria (both ACR-97 and SLICC-12) were recorded, and the date of disease classification using ACR-97 or SLICC-12 criteria was compared to determine which criteria resulted in earlier classification.

Results

Among 182 SLE patients (74.2% Chinese, 18.1% Malay, 4.4% Indian and 3.3% Other ethnicities), 10 (5.5%) did not fulfill the ACR-97 criteria and 2 (1.1%) did not fulfill the SLICC-12 criteria. Using the SLICC-12 criteria, 18% of subjects showed earlier classification, whereas 7% of subjects showed earlier classification using the ACR-97 criteria. The SLICC hematologic criteria of “Leukopenia or lymphopenia” contributed most significantly to earlier diagnosis by SLICC-12. “Leukopenia or lymphopenia'' was present in 59% (19/32) of patients where SLICC-12 criteria allowed for earlier classification than ACR-97, compared with 15.4% (2/13) of patients where ACR-97 allowed earlier classification than SLICC-12 ( p = 0.02). The immunologic criterion that is considered a strength of the SLICC-12 criteria did not appear to contribute significantly to earlier diagnosis in this study.

Conclusion

SLICC-12 criteria allow for earlier classification of SLE in a multiethnic cohort of Asian patients, supporting the validity of the SLICC-12 criteria and its use in clinical care and research.

Crystal structure of 1-(5-bromo-1-benzo-furan-2-yl)ethanone oxime

The title compound, C₁₀H₈BrNO₂, is almost planar (r.m.s. deviation for the non-H atoms = 0.031 Å) and the conformation across the C=N bond is trans. Further, the O atom of the benzo­furan ring is syn to the N atom of the oxime group. In the crystal, inversion dimers linked by pairs of O—H⋯N hydrogen bonds generate R₂²(6) loops. Very weak aromatic π–π stacking inter­actions [centroid–centroid separations = 3.9100 (12) and 3.9447 (12) Å] are also observed.

Crystal structure of ethyl (6-hy-droxy-1-benzo-furan-3-yl)acetate sesquihydrate

In the title hydrate, C12H12O4·1.5H2O, one of the water mol-ecules in the asymmetric unit is located on a twofold rotation axis. The mol-ecule of the benzo-furan derivative is essentially planar (r.m.s. deviation for the non-H atoms = 0.021 Å), with the ester group adopting a fully extended conformation. In the crystal, O-H⋯O hydrogen bonds between the water mol-ecules and the hy-droxy groups generate a centrosymmetric R 6 (6)(12) ring motif. These R 6 (6)(12) rings are fused, forming a one-dimensional motif extending along the c-axis direction.

2-(6-Hy-droxy-1-benzo-furan-3-yl)acetamide

In the title compound, C₁₀H₉NO₃, the dihedral angle between the benzo­furan ring system (r.m.s. deviation for the non-H atoms = 0.009 Å) and the –C—C(O)—N– segment is 83.76 (1)°. In the crystal, mol­ecules are linked by N—H⋯O and O—H⋯O hydrogen bonds, generating (001) sheets, which feature C(4) and C(10) chains.

Inflammatory aspects of sleep apnea and their cardiovascular consequences

Obstructive sleep apnea (OSA) is a common medical condition that occurs in a considerable percentage of the population. Substantial evidence shows that patients with OSA have an increased incidence of hypertension compared with individuals without OSA, and that OSA is a risk factor for the development of hypertension. It is established that OSA may be implicated in stroke and transient ischemic attacks. OSA is associated with coronary heart disease, heart failure, and cardiac arrhythmias. Pulmonary hypertension may be associated with OSA, especially in patients with pre-existing pulmonary disease. Although the exact cause that links OSA with cardiovascular disease is unknown, there is evidence that OSA is associated with a group of proinflammatory and prothrombotic factors that have been identified as important in the development of atherosclerosis. OSA is associated with increased daytime and nocturnal sympathetic activity. Autonomic abnormalities seen in patients with OSA include increased resting heart rate, decreased R-R interval variability, and increased blood pressure variability. Both atherosclerosis and OSA are associated with endothelial dysfunction, increased C-reactive protein, interleukin 6, fibrinogen, plasminogen activator inhibitor, and reduced fibrinolytic activity. OSA has been associated with enhanced platelet activity and aggregation. Leukocyte adhesion and accumulation on endothelial cells are common in both OSA and atherosclerosis. Clinicians should be aware that OSA may be a risk factor for the development of cardiovascular disease.

Moraxella catarrhalis induces mast cell activation and nuclear factor kappa B-dependent cytokine synthesis

Human mast cells are often found perivascularly and at mucosal sites and may play crucial roles in the inflammatory response. Recent studies have suggested a prominent role for mast cells in host defense. In this study, we analyzed the effects of a common airway pathogen, Moraxella catarrhalis and a commensal bacterium, Neiserria cinerea, on activation of human mast cells. Human mast cell leukemia cells (HMC-1) were activated with either phorbol myristate acetate (PMA) and calcium ionophore or with varying concentrations of heat-killed suspensions of bacteria. Supernatants were assayed for the cytokines interleukin-4 (IL-4), granulocyte macrophage colony stimulating factor (GM-CSF), IL-6, IL-8, IL-13 and monocyte chemotactic protein-1 (MCP-1). Nuclear proteins were isolated and assayed by electrophoretic mobility shift assay (EMSA) for nuclear factor kappaB (NF-kappaB) nuclear binding activity. In some experiments, NF-kappaB inhibitor, Bay-11 was added to determine functional significance. Both M. catarrhalis and N. cinerea induced mast cell activation and selective secretion of two key inflammatory cytokines, IL-6 and MCP-1. This was accompanied by NF-kappaB activation. Neither spun bacterial supernatants nor bacterial lipopolysaccharide induced cytokine secretion, suggesting need for direct bacterial contact with mast cells. Scanning electron microscopy revealed active aggregation of bacteria over mast cell surfaces. The NF-kappaB inhibitor, Bay-11, inhibited expression of MCP-1. These findings suggest the possibility of direct interactions between human mast cells and common bacteria and provide evidence for a novel role for human mast cells in innate immunity.

Insulin: a novel factor in carcinogenesis

Cancer is a leading cause of mortality in the United States. Despite much research on specific carcinogens, the cause of many cancers remains unclear. The identification of novel causative agents offers the potential for cancer prevention. Diseases such as obesity and diabetes mellitus, characterized by hyperinsulinemia, are associated with increased risk of endometrial, colorectal, and breast carcinomas. There is increasing evidence that insulin is a growth factor for tumor formation. The mechanisms underlying insulin-mediated neoplasia may include enhanced DNA synthesis with resultant tumor cell growth, inhibition of apoptosis, and altered sex hormone milieu. The reduced insulin levels seen with physical activity, weight loss, and a high fiber diet may account for decreased cancer risk. The role of newer drugs that restore sensitivity to insulin, thereby reducing hyperinsulinemia, is an exciting potential area of cancer prevention. In this review, we discuss the potential role of insulin as a tumor growth factor.

Identification of a novel cytokine, ML-1, and its expression in subjects with asthma

A novel gene, designated ML-1, was identified from a human genomic DNA clone and human T cell cDNA sequences. The second exon of ML-1 gene shares significant sequence identity with the gene encoding IL-17 (IL-17). ML-1 gene expression was up-regulated in activated PBMCs, CD4(+) T cells, allergen-specific Th0, Th1, and Th2 clones, activated basophils, and mast cells. Increased expression of the ML-1 gene, but not IL-17, was seen following allergen challenge in four asthmatic subjects, suggesting its role in allergic inflammatory responses. ML-1 from transiently transfected COS-7 cells was able to induce gene expression and protein production for IL-6 and IL-8 (at 10 ng/ml of ML-1: for IL-6, 599.6 +/- 19.1 pg/ml; for IL-8, 1724.2 +/- 132.9 pg/ml; and at 100 ng/ml of ML-1: for IL-6, 1005.3 +/- 55.6 pg/ml; for IL-8, 4371.4 +/- 280.5 pg/ml; p < 0.05 for both doses vs baseline) in primary bronchial epithelial (PBE) cells. Furthermore, increased expression of ICAM-1 was found in ML-1-stimulated PBE cells (mean fluorescence intensity (MFI) = 31.42 +/- 4.39 vs baseline, MFI = 12.26 +/- 1.77, p < 0.05), a functional feature distinct from IL-17 (MFI = 11.07 +/- 1.22). This effect was not inhibited by a saturating amount of IL-17. These findings demonstrate that ML-1 is a novel cytokine with a distinct function, and suggest a different receptor for ML-1 on PBE cells.

The human mast cell: functions in physiology and disease

Mast cells are multifunctional, tissue-dwelling cells capable of secreting a wide variety of mediators. They develop from bone marrow-derived progenitor cells, primed with stem cell factor (SCF), which mediates its actions by interacting with the SCF receptor or c-kit on the cell surface. Mast cells continue their maturation and differentiation in peripheral tissue, developing into two well described subsets of cells, MCT and MCTC cells, varying in content of tryptase and chymase as well as in immunobiology. Mast cells are activated by numerous stimuli, including antigen (acting via the high affinity IgE receptor, Fc?RI), superoxides, complement proteins, neuropeptides and lipoproteins resulting in activation and degranulation. Following activation, these cells express mediators such as histamine, leukotrienes and prostanoids, as well as proteases, and many cytokines and chemokines, pivotal to the genesis of an inflammatory response. Recent data suggests that mast cells may play an active role in such diverse diseases as atherosclerosis, malignancy, asthma, pulmonary fibrosis and arthritis. Mast cells directly interact with bacteria and appear to play a vital role in host defense against pathogens. Drugs, such as glucocorticoids, cyclosporine and cromolyn have been demonstrated to have inhibitory effects on mast cell degranulation or mediator release.

Treatment strategies for bronchial asthma: an update

Advances in understanding the biomolecular basis of the disease's inflammatory and remodeling responses are offering new therapeutic choices--and sometimes new drug-delivery systems--in categories such as beta-agonists, glucocorticoids, and leukotriene blockers. Meanwhile, researchers are exploring novel targets, including intercellular signals and cell-adhesion and gene-activating molecules.

The effects of HIV infection on endothelial function

Endothelial dysfunction and/or injury is pivotal to the development of cardiovascular and inflammatory pathology. Endothelial dysfunction and/or injury has been described in Human Immunodeficiency Virus (HIV) infection. Elaboration of circulating markers of endothelial activation, such as soluble adhesion molecules and procoagulant proteins, occurs in HIV infection. Certain endothelial cells, such as those lining liver sinusoids, human umbilical vein endothelial cells, bone marrow stromal endothelial cells or brain microvascular endothelial cells, have been shown to be variably permissive for HIV infection. Entry of virus into endothelial cells may occur via CD4 antigen or galactosyl-ceramide receptors. Other mechanisms of entry including chemokine receptors have been proposed. Nevertheless, endothelial activation may also occur in HIV infection either by cytokines secreted in response to mononuclear or adventitial cell activation by virus or else by the effects of the secreted HIV-associated proteins, gp 120 (envelope glycoprotein) and Tat (transactivator of viral replication) on endothelium. Enhanced adhesiveness of endothelial cells, endothelial cell proliferation and apoptosis as well as activation of cytokine secretion have all been demonstrated. Synergy between select inflammatory cytokines and viral proteins in inducing endothelial injury has been shown. In HIV infection, dysfunctional or injured endothelial cells potentiate tissue injury, inflammation and remodeling, and accelerate the development of cardiovascular disease.

Reactive and clonal thrombocytosis: proinflammatory and hematopoietic cytokines and acute phase proteins

BACKGROUND

We quantitated proinflammatory and thrombopoietic cytokines in reactive thrombocytosis (RT) and clonal thrombocytosis (CT) to identify a cytokine profile that might aid in the distinction of these two disorders.

METHODS

Serum levels of cytokines relevant to platelet biology--interleukins 3, 6, 11, and 1beta; thrombopoietin; tumor necrosis factor alpha; and C-reactive protein (CRP)--were measured by enzyme-linked immunosorbent assay in healthy subjects and in patients with CT and RT.

RESULTS

Interleukin-6 and CRP levels were higher in RT patients than in controls or CT patients. Interleukin 1beta levels were higher in the RT group than in the CT and control groups.

CONCLUSIONS

In RT, IL-6, IL-1beta, and CRP levels are elevated. In both RT and CT, IL-11 is elevated, but thrombopoietin levels are not.

Acute and chronic urticaria. Challenges and considerations for primary care physicians

Urticaria and angioedema are common dermatologic problems seen by primary care physicians. A carefully taken history, physical examination, specific tests, and skin biopsy often provide useful diagnostic information. In patients with chronic urticaria, urticarial vasculitis and diseases that mimic urticaria need to be ruled out. A variety of treatment options are available for patients with urticaria and urticarial vasculitis. Pharmacologic therapy is useful when the specific cause is undetermined. When a trigger has been identified, the patient must avoid exposure to it. Patient education is an important component of management and should include instructions on crisis management, particularly for patients who have angioedema or a tendency for anaphylaxis.

Difficult-to-manage asthma. How to pinpoint the exacerbating factors

In difficult-to-manage asthma, effective control depends on identification and alleviation of exacerbating factors, such as ongoing allergen exposure, chronic sinusitis, GERD, and emotional stress. Level of compliance with the prescribed medication regimen should be evaluated in all patients. Hormonal factors (i.e., menses, use of exogenous hormones by female patients, and hyperthyroidism) also can exacerbate asthma. When aggressive management fails, the possibility of a misdiagnosis should be considered. Other conditions that can mimic asthma include COPD, congestive heart failure, airway obstruction due to various causes, vocal cord dysfunction, and esophageal spasm. Referral to an asthma specialist is advised in severe or resistant cases.

The cardiovascular and metabolic complications of HIV infection

With the advent of more effective therapies for human immunodeficiency virus (HIV) infection, HIV-infected patients are living longer and cardiovascular disease is becoming more obvious in this population. Patients with HIV infection represent one of the most rapidly developing groups with cardiovascular disease globally. Cardiovascular disease complicating HIV infection is likely to contribute to burgeoning healthcare costs. Pericarditis, myocarditis, cardiomyopathy, atherosclerotic coronary vasculopathy, arterial aneurysms, pulmonary hypertension, and endocarditis occur with increased frequency in these patients. Pericardial tamponade, dilated cardiomyopathy, endocarditis, and vasculopathy can lead to fatal outcomes in this population. The advent of cardiomyopathy heralds a very poor prognosis in patients infected with HIV. Coronary vasculopathy without obvious risk factors can lead to myocardial ischemia in young patients infected with the virus. Moreover, the protease inhibitors used to treat HIV infection induce a syndrome of lipodystrophy and dyslipidemia that may be associated with accelerated atherosclerosis as well as insulin resistance. All these factors contribute to increased cardiovascular morbidity and mortality in the HIV-infected population. HIV infection, opportunistic infections, secreted viral proteins such as gp120 (envelope protein) or Tat (transactivator of viral transcription), and cytokines elaborated during the course of HIV infection of the immune system all contribute to pathogenesis of these disorders. Further basic and clinical studies are required to understand the pathogenesis of cardiovascular complications and develop appropriate management strategies for these patients.

The molecular role of mast cells in atherosclerotic cardiovascular disease

Human atherosclerosis has many characteristics of an inflammatory disorder. Recent data suggest that mast cells might be important in the pathogenesis of atherosclerotic disease. By secretion of pro-inflammatory cytokines, mast cells can assist in the recruitment of monocytes and lymphocytes into vascular tissue, thereby propagating the inflammatory response. Mast cell enzymes might activate pro-metalloproteinases, thereby destabilizing atheromatous plaques. Mast cells can facilitate foam cell formation by promoting cholesterol accumulation. However, mast cell tryptase could slow thrombus formation at sites of plaque rupture by interfering with coagulation. Therefore, mast cells can modulate coronary artery disease by both facilitatory and inhibitory pathways.

Long-term exercise and atherogenic activity of blood mononuclear cells in persons at risk of developing ischemic heart disease

CONTEXT

Increasing evidence demonstrates that atherosclerosis is an immunologically mediated disease in which the secretion of atherogenic and atheroprotective cytokines, by infiltrating blood mononuclear cells, plays an important role. It is not known whether long-term exercise alters this atherogenic and atheroprotective activity directly.

OBJECTIVE

To determine the effect of long-term exercise on the atherogenic activity of blood mononuclear cells in persons at risk of developing ischemic heart disease.

DESIGN

Before-after trial using a 6-month individualized, supervised exercise program, with an enrollment period from December 1996 to October 1997.

SETTING

Hospital-based community wellness center.

PARTICIPANTS

Of 110 persons who responded to a public request for volunteers, 52 met the inclusion criteria (risk ratio for myocardial infarction > or =1.7 based on serum complement and/or C-reactive protein levels, and normal exercise treadmill test results). Forty-three of the 52 enrollees (25 women [mean age, 49.7 years] and 18 men [mean age, 48.1 years]) completed the study; 9 withdrew for personal reasons. Additional risk factors for ischemic heart disease included hypercholesterolemia (65.1 %), a family history of coronary heart disease (62.8%), inactivity (60.5%), hypertension (32.6%), obesity (25.6%), smoking (11.6%), and diabetes mellitus (4.7%).

MAIN OUTCOME MEASURES

Blood levels were compared at baseline and after the exercise program had been completed for the following: spontaneous and phytohemagglutinin-induced production of interleukin 1 alpha, tumor necrosis factor alpha, and interferon gamma (atherogenic cytokines), and interleukin 4, interleukin 10, and transforming growth factor beta 1 (atheroprotective cytokines) by blood mononuclear cells; lymphocyte phenotypes and mitogenic responses to phytohemagglutinin; and serum C-reactive protein levels.

RESULTS

Subjects exercised for a mean of 2.5 (range, 0.3-7.4) hours per week. Mononuclear cell production of atherogenic cytokines fell by 58.3 % (P<.001) following the exercise program, where as the production of atheroprotective cytokines rose by 35.9% (P<.001). Changes in transforming growth factor beta 1 and in phytohemagglutinin-induced atherogenic cytokine production after the exercise program were proportionate to the time subjects spent performing repetitive lower-body motion exercises (P<.02), indicating a dose-response relationship. After the exercise program, changes in cellular function were reflected systemically by a 35% decrease in serum levels of C-reactive protein (P=.12).

CONCLUSIONS

Our data suggest that long-term exercise decreases the atherogenic activity of blood mononuclear cells in persons at risk of developing ischemic heart disease. This may be a mechanism whereby physical activity protects against ischemic heart disease.

Differential regulation of antigen-induced IL-4 and IL-13 generation from T lymphocytes by IFN-alpha

BACKGROUND

IL-4 and IL-13 are related cytokines with similar functional properties. Differential regulation of IL-4 and IL-13 has not been described.

OBJECTIVE

We have examined the effects of IFN-alpha on antigen-driven proliferation, IL-4 generation, and IL-13 generation from human PBMCs and T-cell clones.

METHODS

Proliferation was assessed by 3H-thymidine incorporation. Cytokine generation was assessed by reverse transcription PCR and ELISA. Messenger RNA stability was assessed in the presence of actinomycin D.

RESULTS

IFN-alpha induced a concentration-dependent inhibition of antigen-driven proliferation of TH1 and TH2 clones (median effective concentration, 150 to 200 U/mL); the sensitivity of TH1 and TH2 clones to IFN-alpha was not significantly different (P =.6). IFN-alpha induced an analogous concentration-dependent inhibition of antigen-driven IL-13 generation from TH1 and TH2 clones (median effective concentration, 100 U/mL); this effect was evident by 12 hours of culture and persisted beyond 48 hours. However, IL-4 generation from TH2 clones was insensitive to IFN-alpha at all concentrations and times tested (1 to 10,000 U/mL). A similar inhibitory effect of IFN-alpha on mitogen-driven proliferation and IL-13 generation from PBMCs was demonstrated; once again, IL-4 generation from PBMCs was insensitive to IFN-alpha. IL-13 mRNA stability was unaffected by IFN-alpha, suggesting transcriptional regulation.

CONCLUSION

IFN-alpha differentially regulates antigen-stimulated IL-4 and IL-13 generation.

Human endothelium as a source of multifunctional cytokines: molecular regulation and possible role in human disease

Endothelial cells, by virtue of their capacity to express adhesion molecules and cytokines, are intricately involved in inflammatory processes. Endothelial cells have been shown to express interleukin-1 (IL-1), IL-5, IL-6, IL-8, IL-11, IL-15, several colony-stimulating factors (CSF), granulocyte-CSF (G-CSF), macrophage CSF (M-CSF) and granulocyte-macrophage CSF (GM-CSF), and the chemokines, monocyte chemotactic protein-1 (MCP-1), RANTES, and growth-related oncogene protein-alpha (GRO-alpha). IL-1 and tumor necrosis factor-alpha (TNF-alpha) produced by infiltrating inflammatory cells can induce endothelial cells to express several of these cytokines as well as adhesion molecules. Induction of these cytokines in endothelial cells has been demonstrated by such diverse processes as hypoxia and bacterial infection. Recent studies have demonstrated that adhesive interactions between endothelial cells and recruited inflammatory cells can also signal the secretion of inflammatory cytokines. This cross-talk between inflammatory cells and the endothelium may be critical to the development of chronic inflammatory states. Endothelial-derived cytokines may be involved in hematopoiesis, cellular chemotaxis and recruitment, bone resorption, coagulation, and the acute-phase protein synthesis. As many of these processes are critical to the maturation of an inflammatory and reparative state, it appears likely that endothelial-derived cytokines play a crucial role in several diseases, including atherosclerosis, graft rejection, asthma, vasculitis, and sepsis. Genetic and pharmacologic manipulation of endothelial-derived cytokines provides an additional approach to the management of chronic inflammatory diseases.

Severe bactrim-induced neutropenia with reversal of CD4+/CD8+ lymphocyte ratio: response to recombinant human granulocyte-colony stimulating factor (R-metHUG-CSF)

A patient presented with severe bactrim-induced neutropenia with a reversed CD4+/CD8+ lymphocyte ratio. R-metHUG-CSF at 300 micrograms daily produced a dramatic neutrophil response and the therapy was discontinued after 2 weeks.

Multifunctional cytokine expression by human coronary endothelium and regulation by monokines and glucocorticoids

Human endothelium is capable of expressing a variety of molecules, including cytokines and growth factors, critical to inflammation. This aspect of coronary endothelium has not been studied in detail. In this study, we report, for the first time, expression of multifunctional cytokines by human coronary artery endothelial cells (HCAEC) and their regulation by inflammatory cytokines and glucocorticoids. We also compared expression of cytokine transcripts in two additional cell lines derived from pulmonary artery (HPAEC) and umbilical vein (HUVEC) endothelium. HCAEC expressed transcripts for interleukin 5 (IL-5), IL-6, IL-8, and monocyte chemotactic protein-1 (MCP-1) constitutively. Induction of IL-1alpha, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), and MCP-1 was seen following treatment with TNFalpha. We found no expression of IL-1RA, IL-2, IL-4, IL-13, TNF-alpha, or IFN-gamma in HCAEC. IL-1beta and TNF-alpha synergistically induced IL-6 and GM-CSF and additively induced IL-8 and MCP-1 production, while IL-2, IL-10, IFN-alpha, and IFN-gamma had little or no additional effects. Interestingly, no IL-1alpha or IL-5 protein product was found even after maximal stimulation of HCAEC. No significant differences were seen in the profile of cytokine genes expressed by HCAEC, HPAEC, or HUVEC. Glucocorticoids inhibited IL-8 production from all three cell lines. This study demonstrates that human coronary endothelial cells are capable of expressing a wide variety of multifunctional cytokines which may be of relevance to vascular inflammation.

Prostaglandin H synthase expression is variable in human colorectal adenocarcinoma cell lines

The expression of prostaglandin H synthases can be induced by many stimuli and is likely to be important in control of the cell cycle. The analysis of prostaglandin H synthase-1 and -2 expression in colon adenocarcinoma cell lines is a useful model system for studying the function of the prostaglandin H synthases, especially with regard to proliferation and adhesion. Prostaglandin H synthase-1 protein is not found in any of eight human colon adenocarcinoma cell lines. Expression of prostaglandin H synthase-2 is variable for the eight cell lines: three constitutively expressed active protein, four did not express this gene at all, and one had mRNA but no active protein. Thus, five colorectal adenocarcinoma cell lines exhibit "null" expression of prostaglandin synthase-2. The three cell lines with constitutive expression of prostaglandin H synthase-2 produce PGE2. Prostaglandin E2 production could be inhibited by aspirin and NS398 without inhibiting proliferation, while direct addition of prostaglandin E2 inhibits proliferation. Adhesion to collagen IV and fibronectin was stronger in those cell lines that expressed prostaglandin H synthase-2. The constitutive expression of prostaglandin H synthase-2 is associated with increased adhesion to extracellular matrix components and a potential inhibition of proliferation through the production of prostaglandin E2. The absence of PGH synthase-2 expression in some cell lines may result from the original tumor's need to inactivate these associated functions. Our evidence suggests that PGH synthase-2 is a possible candidate for a tumor suppressor gene at 1q23-qter.

Immunologic investigations of T-cell regulation of human IgE antibody secretion and allergic responses

The pathophysiology of allergic disease is multifactorial, involving an intricate network of interactions among cells, mediators, and cytokines. Substantial progress has been made in defining the role of antigen-specific T cells and cytokines in the regulation of immunoglobulin E (IgE) synthesis and the atopic diseases. The development of antigen-specific T-cell lines and clones has facilitated efforts to characterize human T-cell subsets and their cytokine repertoires. Molecular methods currently available include techniques for the quantitative analysis of cytokine gene expression and secretion from activated T cells ex vivo as well as in tissues. The availability of these newly developed techniques has become essential to the investigation of the pharmacologic regulation of T cells and cytokines both in vitro and in vivo. Future investigations will contribute to our understanding of the differential regulation of T-cell subsets and their relationships to allergic diseases, ultimately leading to a better understanding of the molecular pathogenesis of allergic diseases and the design of more effective therapeutic interventions.

Multifunctional cytokine expression by human mast cells: regulation by T cell membrane contact and glucocorticoids

Human mast cells readily release a variety of mediators, including cytokines, in response to IgE receptor crosslinking, but the mechanisms governing the expression of cytokines are still unclear. Using a human mast cell line, HMC-1, we show expression of cytokine transcripts as early as 2 h after activation with ionomycin and phorbol myristate acetate (PMA). Resting HMC-1 cells expressed transcripts for interleukin-1 receptor antagonist (IL-1RA), IL-2, IL-4, IL-5, GM-CSF, and weakly for IL-8, and stimulation with ionomycin and PMA induced additional transcripts for IL-6 and IL-13 and upregulated expression of IL-8 transcripts. HMC-1 cells secreted IL-4, IL-8, and GM-CSF protein after activation and dexamethasone significantly inhibited the production of these cytokines. Of significance is the finding that the addition of membranes purified from activated T cells to mast cell cultures induced transcripts selectively for IL-8 and none for other proinflammatory cytokines. Flow cytometry revealed that resting HMC-1 cells express CD40, a molecule involved in contact-dependent signaling of monocytes and B cells by T cells. However, activation of HMC-1 by anti-CD40 antibody did not induce IL-8 gene expression or protein production. This study demonstrates that human mast cells are capable of expressing multiple cytokines that can be inhibited by glucocorticoids. It also raises the possibility that T cells may activate mast cell cytokine synthesis by novel contact-dependent mechanisms. This phenomenon of T cell regulation of mast cell function requires further study.

Persistent urticarial eruption in an asthmatic patient

This case demonstrates the importance of recognizing urticarial vasculitis in patients with chronic urticarial eruptions. The salient points in history that point towards the diagnosis of urticarial vasculitis include the presence of painful urticarial lesions that last longer than 24 hours and that heal leaving residual pigmentation. In some cases the urticaria may evolve into palpable purpura. An associated systemic illness that may resemble systemic lupus erythematosus should also suggest the diagnosis, which is established by skin biopsy. Histopathology reveals a leukocytoclastic vasculitis involving postcapillary venules. When associated with systemic vasculitis, the urticaria is likely to be of the hypocomplementemic variety, with immunoglobulin and complement deposition on biopsies, and with serum complement studies demonstrating classical pathway activation, low C1q levels, and anti-C1q precipitins. A variety of agents have been used in the management of urticarial vasculitis, including aspirin, nonsteroidal anti-inflammatory agents, corticosteroids, colchicine, dapsone, hydroxychloroquine, and cytotoxic agents such as cyclophosphamide and azathioprine.

A newly developed PCR assay of H. pylori in gastric biopsy, saliva, and feces. Evidence of high prevalence of H. pylori in saliva supports oral transmission

We have recently developed a new PCR assay for the detection of H. pylori. In this study, the polymerase chain reaction (PCR) assay was used to detect H. pylori in 88 gastric biopsy, 85 saliva, and 71 fecal specimens from 88 patients. H. pylori infection was confirmed in 71 of 88 patients by culture and/or histological stain of gastric biopsies. Serum IgG antibody to H. pylori was also measured and resulted in 97% sensitivity and 94% specificity. H. pylori DNA was detected by the PCR assay in gastric biopsy specimens from all 71 patients (100% sensitivity) with proven gastric H. pylori infection but not from 17 noninfected patients (100% specificity). In saliva specimens, H. pylori DNA was identified in 57 of the 68 patients (84%) with proven gastric H. pylori infection and in three of the 17 patients without gastric H. pylori infection. However, the PCR assay was only able to detect H. pylori DNA in the feces from 15 of 61 patients (25%) with proven gastric H. pylori infection and one of the 10 patients without gastric H. pylori infection. The results show that the PCR assay is reliable for detecting the presence of H. pylori in gastric biopsy and saliva specimens. The data indicate that H. pylori exists in a higher prevalence in saliva than feces and that the fecal-oral route may be an important means of transmission of this infection in developing countries but not as significant as previously suspected in the developed countries. It is likely that the oral-oral route is more prominent.

Lymphoblastoid interferon-alpha inhibits T cell proliferation and expression of eosinophil-activating cytokines

T cell-derived cytokines, such as interleukin-5 (IL-5) and granulocyte-macrophage colony-stimulating factor (GM-CSF) activate eosinophils, whereas other cytokines, such as tumor necrosis factor (TNF)-alpha and IL-13, determine eosinophil recruitment. Interferon-alpha (IFN-alpha), a leukocyte-derived cytokine, has been shown to have beneficial effects in eosinophil-mediated disorders, such as the hypereosinophilic syndrome and a murine model of allergic asthma, where it inhibited eosinophil recruitment. We tested the hypothesis that IFN-alpha acted in eosinophil-mediated disorders by modulating T cell cytokine expression. Peripheral blood mononuclear cells (PBMC) or human ragweed-specific TH1 (2B8) and TH2 (2D2) T cell clones were cultured in the presence of 5 micrograms/ml of phytohemagglutinin (PHA) or 25 micrograms/ml of antigen Amb a 1 (short ragweed allergen), respectively, and lymphoblastoid IFN-alpha (varying from 0 to 10,000 U/ml). We assessed T cell proliferation by [3H]thymidine incorporation and production of IL-5 and GM-CSF by ELISA. Expression of cytokine transcripts was analyzed by the reverse transcription-polymerase chain reaction technique (RT-PCR). IFN-alpha induced a dose-dependent suppression of T cell proliferation of both PBMC (p < 0.001) and the T cell clones (p < 0.001). IFN-alpha inhibited gene expression of IL-5, GM-CSF, TNF-alpha, and IL-13 in PBMC. Furthermore, IFN-alpha significantly inhibited mitogen-induced and antigen-induced production of IL-5 and GM-CSF. IFN-alpha may benefit eosinophil-mediated disorders by inhibiting T cell function and production of cytokines active on human eosinophils.

Resolution of the neutropenia of Felty's syndrome by longterm administration of recombinant granulocyte colony stimulating factor

Felty's syndrome is characterized by neutropenia, splenomegaly, and recurrent infection in patients with rheumatoid arthritis. We used recombinant granulocyte colony stimulating factor (rGCSF) in a patient with Felty's syndrome and recurrent sepsis. rGCSF induced a statistically significant increase in the patient's absolute neutrophil and total white blood cell counts. During 14 months of followup taking rGCSF, disseminated varicella zoster was the only infectious complication. Except mild thrombocytopenia and a transient flare of arthritis, no serious adverse effects occurred. rGCSF may be a safe and effective therapy for Felty's syndrome in selected patients.

Appearance of drug-resistant tuberculosis in rural Tennessee

Drug-resistant tuberculosis (DRTB) is a growing national health concern in both urban populations and rural areas and is exacerbated by the growing epidemic of human immunodeficiency virus (HIV) infection. Between 1989 and 1992, 7 cases of DRTB (5 with multidrug-resistance) were diagnosed in an eight-county region of East Tennessee. During 1990 and 1991 alone, 5 of 100 patients with tuberculosis had drug-resistant strains (5%). All 7 patients with DRTB had 100% resistance to isoniazid; 5 also had resistance to streptomycin, 2 to rifampin, and 1 to pyrazinamide and ethambutol. All patients were white, U.S.-born, and without evidence of HIV infection. Contact investigation revealed that more contacts of patients with DRTB (13 of 74, 18%) were infected than were contacts of patients with drug-sensitive tuberculosis (46 of 290, 16%). Our study demonstrates that DRTB is not confined to geographically distinct areas, but may be a subtle and easily missed diagnosis in presumably low-risk rural populations.

Linkage analysis of IL4 and other chromosome 5q31.1 markers and total serum immunoglobulin E concentrations

Sib-pair analysis of 170 individuals from 11 Amish families revealed evidence for linkage of five markers in chromosome 5q31.1 with a gene controlling total serum immunoglobulin E (IgE) concentration. No linkage was found between these markers and specific IgE antibody concentrations. Analysis of total IgE within a subset of 128 IgE antibody-negative sib pairs confirmed evidence for linkage to 5q31.1, especially to the interleukin-4 gene (IL4). A combination of segregation and maximum likelihood analyses provided further evidence for this linkage. These analyses suggest that IL4 or a nearby gene in 5q31.1 regulates IgE production in a nonantigen-specific (noncognate) fashion.

Detection of allergen- and mitogen-induced human cytokine transcripts using a competitive polymerase chain reaction

Human cytokines, IL-4, IL-5, and IFN-gamma play an important role in the regulation of IgE synthesis and atopic diseases. In this communication, we describe the development of a quantitative assay of steady-state cytokine mRNAs (IL-4, IL-5, and IFN-gamma) from a variety of cell sources, including peripheral blood mononuclear cells (PBMCs) stimulated with either a mitogen (PHA) or ragweed pollen allergen extract, and cells from allergen-challenged inflammatory sites. Quantitative analysis of IL-5, IL-4 and IFN-gamma transcripts was achieved by a competitive reverse transcription-polymerase chain reaction (RT-PCR) technique using internal standard (IS) cRNAs in the presence of specific oligonucleotide primers. Each IS was generated from a plasmid vector containing the respective cytokine cDNA modified by insertion with an SV40-DNA fragment. Both test RNA and IS were reverse-transcribed and subjected to the 'competitive' PCR in the same tube. We first demonstrate the linearity and reproducibility of this technique; second, we apply this competitive PCR assay to analyze quantitatively the expression of IL-4, IL-5, and IFN-gamma transcripts in PBMCs before and after stimulation with PHA or crude ragweed allergen. Finally, we analyzed cells isolated from the lung lavage fluids of an atopic subject following allergen challenge, and showed a significant increase of IL-4 and IL-5 transcripts, but not IFN-gamma, in the allergen-challenged site when compared to the control. This technique of PCR quantitation provides an easy and efficient tool to study the expression of cytokine genes in allergic inflammatory diseases.

Analysis of cytokine transcripts in the bronchoalveolar lavage cells of patients with asthma

A panel of steady-state cytokine mRNAs was analyzed in the bronchoalveolar lavage (BAL) cells from asthmatic subjects or patients challenged with ragweed allergen. This was achieved by combining both qualitative and quantitative assays using the reverse transcription-polymerase chain reaction (RT-PCR). Analysis of BAL cells from six mild allergic asthmatic and five nonasthmatic, nonallergic subjects showed no qualitative differences in the profile of cytokine mRNAs (including interleukin [IL]-1 beta, IL-2, IL-5, IL-6, IL-8, and granulocyte/macrophage colony-stimulating factor), except for tumor necrosis factor-alpha, which was detected in three out of six asthmatic BAL samples but in none of the controls. A key cytokine, IL-5, has been implicated in the pathogenesis of allergic inflammation through the recruitment of eosinophils. We found a significant enhancement of steady-state IL-5 transcripts in the BAL cells from allergen-challenged as compared with the saline-challenged control sites of four asthmatic patients; furthermore, the cellular source for IL-5 mRNA was identified in the mononuclear cell fraction, but not in the purified eosinophils, of the allergen-challenged BALs. These results suggest that the significant increase of IL-5 transcripts is primarily from the infiltrating mononuclear cells. Our study also demonstrates the power of qualitative and quantitative PCR analysis in determining the molecular basis of allergic inflammatory diseases.

Changes in bone mineral content and density after stroke

The purpose of this study was to determine whether there are differences in bone mineral content and density between paralyzed and nonparalyzed sides of patients who had sustained strokes associated with unilateral muscle weakness, to determine the relationship between duration of stroke and degree of demineralization and to compare the degree of demineralization in upper and lower limbs. The bone mineral content and density were measured by dual photon absorptiometry (high resolution scanning mode, Lunar DP4) in ambulant patients with a history of single completed strokes associated with unilateral weakness. The bone mineral content and density of each limb was determined by the region of interest analysis program. In the 30 patients included in this study, the bone mineral content and density were significantly less on the paralyzed than on the nonparalyzed side. The degree of demineralization was more pronounced in the upper than in the lower limbs. The mean percentage differences in bone mineral content and density between paralyzed and nonparalyzed arms were 13.8% (P < 0.00001) and 7.95% (P = 0.0003), respectively, and between paralyzed and nonparalyzed legs the differences were 4.5% (P = 0.0012) and 3.42% (P = 0.0028), respectively. A better correlation was noted between the time elapsed since the stroke and the degree of demineralization in the upper limbs (r = 0.75, P < 0.0001), than in the lower limbs (r = 0.60, P = 0.0004). In conclusion, patients who have strokes associated with muscle weakness are at an increased risk of developing osteoporosis on the paralyzed side and particularly in the upper limbs.

The effect of interferon-gamma, interleukin-4 and immunoglobulin receptor cross-linking of monocytes on allergen-specific T-cell response

Modulation of the proliferative responses of an allergen-specific human Th2 cell line by cytokine-treated monocytes was examined. The response of this cell line to the specific allergen, Amb a V (from short ragweed pollen), increased following the addition of interleukin-1 beta (IL-1 beta). However, in the presence of exogenous interferon-gamma (IFN-gamma), there was greater than 40% reduction in the responsiveness of these T cells. The addition of IL-1 beta did not reverse the inhibitory effect of IFN-gamma. To determine the primary target cell type for IFN-gamma, autologous monocytes were pretreated with IL-4, IFN-gamma, or medium alone, and used as antigen-presenting cells (APC). We showed that the responses of T cells to Amb a V were significantly down-regulated in the presence of autologous monocytes pretreated with IFN-gamma, but not for monocytes pretreated with IL-4. Similar inhibitory effect of IFN-gamma was confirmed using a human T-cell line specific for a ragweed allergen, Amb a I, and a human T-cell clone raised against ragweed extract. Cross-linking of CD23 (Fc epsilon RII) on monocytes pretreated with IFN-gamma increased this inhibitory effect in an additive fashion, but, in the absence of IFN-gamma treatment, such cross-linking had no effect. These inhibitory effects were not due to alterations in the surface expression of HLA-DR on the monocytes, and the addition of exogenous IL-1 beta was unable to reverse these effects. In similar experiments, cross-linking of CD64 (Fc gamma R) on monocytes showed no significant effects. In conclusion, IFN-gamma is important in regulating the function of monocytes involved in Th2 cell responses to allergens. IL-4 treatment, as well as cross-linking of FcR of monocytes, have no direct effect on such response.

Cell killing and chromosomal aberrations induced in Chinese hamster ovary cells by treating with cisplatin at 41.5 degrees C during the G1 or late S phase

Variation in sensitivity to cisplatin during the cell cycle was studied in synchronous Chinese hamster ovary cells treated during G1 or late S for 1 h at 41.5 degrees C with cisplatin (0.25-1.25 micrograms/ml, 0.8-4.2 x 10(-6) M). The cells were assayed for cell killing and chromosomal aberrations. Either they were plated for colony survival, or colcemid was added from 12 to 40 h after plating followed by fixation 4 h later for analysis of chromosomal aberrations after the cells completed 1 or 2 cycles (i.e., first or second mitosis). When the cells were treated either in G1 or late S, the cells entering metaphase exhibited primarily chromatid-type deletions and exchanges. However, aberrations were observed primarily in the first mitosis when cells were treated in G1 compared with aberrations being observed in both the first and second mitoses when cells were treated in late S. For a given amount of cytotoxicity or cytological damage, the cisplatin concentration at 41.5 degrees C could be reduced 4-6-fold compared with treatment at 37 degrees C. For low cisplatin concentrations of less than 0.5-0.7 microgram/ml (survival, approximately 0.3), heat killing predominated, and cells treated in S phase were more sensitive than those treated in G1. However, for cisplatin concentrations greater than 0.5-0.7 microgram/ml, cisplatin cytotoxicity predominated, and for both cell killing and chromosomal aberrations, the cells treated in G1 were approximately 1.5 times more sensitive than those treated in late S. Furthermore, the positive correlation between survival and aberration frequency was similar for cells treated at 37 degrees C or 41.5 degrees C in either G1 or late S. These results suggest that cisplatin administered at 37 degrees C or 41.5 degrees C causes cell lethality primarily by the induction of chromosomal aberrations.

Critical steps for induction of chromosomal aberrations in CHO cells heated in S phase

The following four effects on DNA replication are observed in cells heated in S phase of the cell cycle: (1) inhibition of replicon initiation, (2) delay in DNA chain elongation into multicluster-sized molecules > 160S, (3) reduction in fork displacement rate, and (4) increase in single-stranded regions in replicating DNA. Since cells heated in S phase manifest chromosomal aberrations when they enter metaphase, whereas cells heated in G1 do not, we attempted to determine if the effects on DNA replication are critical for the induction of chromosomal aberrations by studying these same effects during DNA replication when synchronous CHO cells had been heated (10 min at 45.5 degrees C) in G1 phase. Following a heat-induced G1 block (12 h), we found previously that when the cells entered S phase, replicon initiation was functional and chain elongation into multicluster-sized molecules > 160S was delayed but completed during S phase. In the present study, we find that the fork displacement rate was near normal and that there was no increase in single-stranded DNA. Additionally, an increase in excess nuclear protein induced in the heated G1-phase cells returns to a normal level by about 12 h, just prior to when the cells enter S phase. Since the excess nuclear protein remains for many hours in heated S-phase cells, we hypothesize that the excess nuclear protein is responsible for the drastic reduction in the fork displacement rate and the associated increase in single-stranded DNA. Furthermore, we hypothesize that this persistent increase in single-stranded DNA during replication is a critical step for the induction of chromosomal aberrations in heated S-phase cells. Consistent with this hypothesis, we observed that aphidicolin (1-2 micrograms/ml) treatment of S-phase cells for 13-16 h, which results in a twofold increase in single-stranded DNA during the inhibition of DNA synthesis, also induces chromosomal aberrations. Possibly, endogenous endonucleolytic attack occurs opposite these sites of single-stranded DNA, thus creating double-strand breaks which either can remain unrepaired or are misrepaired to account for the chromatid breaks and exchanges, respectively, observed as cells complete their cell cycle and enter metaphase.

Cisplatin induced cell killing and chromosomal aberrations in CHO cells: treated during G1 or S phase

Variation in sensitivity to cisplatin during the cell cycle was studied in synchronous CHO cells treated during G1 or late S phase. The cells were assayed for cell killing, cell-cycle delay, and chromosomal aberrations after they were treated with cisplatin (1-12 micrograms/ml) for 1 h at 37 degrees C. They were either plated for colony survival, or colcemid was added from 12 to 40 h after plating followed by fixation 4 h later for analysis of chromosomal aberrations after the cells completed 1 or 2 cycles (i.e. first or second mitosis). Cells treated with 6 micrograms/ml exhibited about a 10-h delay during the first cycle after treatment during G1 compared with about 3 h during the first cycle and 6 h during the second cycle after treatment during late S. In both cases, cells entering metaphase exhibited predominantly chromatid-type breaks and exchanges. For both cell killing and chromosomal aberrations, the cells in G1 were 1.5-1.6 times more sensitive than those treated in late S, with 1 aberration per cell corresponding to about 37% survival. However, the exchanges and breaks were observed primarily in the first mitosis when cells were treated in G1 compared with the second mitosis when cells were treated in late S. These results suggest that DNA replication opposite cisplatin cross-links in the DNA results in lethal chromosomal aberrations.