Redox stratification of an ancient lake in Gale crater, Mars

In 2012, NASA's Curiosity rover landed on Mars to assess its potential as a habitat for past life and investigate the paleoclimate record preserved by sedimentary rocks inside the ~150-kilometer-diameter Gale impact crater. Geological reconstructions from Curiosity rover data have revealed an ancient, habitable lake environment fed by rivers draining into the crater. We synthesize geochemical and mineralogical data from lake-bed mudstones collected during the first 1300 martian solar days of rover operations in Gale. We present evidence for lake redox stratification, established by depth-dependent variations in atmospheric oxidant and dissolved-solute concentrations. Paleoclimate proxy data indicate that a transition from colder to warmer climate conditions is preserved in the stratigraphy. Finally, a late phase of geochemical modification by saline fluids is recognized.

Elemental geochemistry of sedimentary rocks at Yellowknife Bay, Gale crater, Mars

Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron- and halogen-rich components, magnesium-iron-chlorine-rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.

Volatile and organic compositions of sedimentary rocks in Yellowknife Bay, Gale crater, Mars

H2O, CO2, SO2, O2, H2, H2S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. H2O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, and amorphous materials. Thermal decomposition of carbonates and combustion of organic materials are candidate sources for the CO2. Concurrent evolution of O2 and chlorinated hydrocarbons suggests the presence of oxychlorine phase(s). Sulfides are likely sources for sulfur-bearing species. Higher abundances of chlorinated hydrocarbons in the mudstone compared with Rocknest windblown materials previously analyzed by Curiosity suggest that indigenous martian or meteoritic organic carbon sources may be preserved in the mudstone; however, the carbon source for the chlorinated hydrocarbons is not definitively of martian origin.

In situ radiometric and exposure age dating of the martian surface

We determined radiogenic and cosmogenic noble gases in a mudstone on the floor of Gale Crater. A K-Ar age of 4.21 ± 0.35 billion years represents a mixture of detrital and authigenic components and confirms the expected antiquity of rocks comprising the crater rim. Cosmic-ray-produced (3)He, (21)Ne, and (36)Ar yield concordant surface exposure ages of 78 ± 30 million years. Surface exposure occurred mainly in the present geomorphic setting rather than during primary erosion and transport. Our observations are consistent with mudstone deposition shortly after the Gale impact or possibly in a later event of rapid erosion and deposition. The mudstone remained buried until recent exposure by wind-driven scarp retreat. Sedimentary rocks exposed by this mechanism may thus offer the best potential for organic biomarker preservation against destruction by cosmic radiation.

Mindfulness meditation-related pain relief: evidence for unique brain mechanisms in the regulation of pain

The cognitive modulation of pain is influenced by a number of factors ranging from attention, beliefs, conditioning, expectations, mood, and the regulation of emotional responses to noxious sensory events. Recently, mindfulness meditation has been found attenuate pain through some of these mechanisms including enhanced cognitive and emotional control, as well as altering the contextual evaluation of sensory events. This review discusses the brain mechanisms involved in mindfulness meditation-related pain relief across different meditative techniques, expertise and training levels, experimental procedures, and neuroimaging methodologies. Converging lines of neuroimaging evidence reveal that mindfulness meditation-related pain relief is associated with unique appraisal cognitive processes depending on expertise level and meditation tradition. Moreover, it is postulated that mindfulness meditation-related pain relief may share a common final pathway with other cognitive techniques in the modulation of pain.

A Closer Look at Water-Related Geologic Activity on Mars

Water has supposedly marked the surface of Mars and produced characteristic landforms. To understand the history of water on Mars, we take a close look at key locations with the High-Resolution Imaging Science Experiment on board the Mars Reconnaissance Orbiter, reaching fine spatial scales of 25 to 32 centimeters per pixel. Boulders ranging up to approximately 2 meters in diameter are ubiquitous in the middle to high latitudes, which include deposits previously interpreted as finegrained ocean sediments or dusty snow. Bright gully deposits identify six locations with very recent activity, but these lie on steep (20 degrees to 35 degrees) slopes where dry mass wasting could occur. Thus, we cannot confirm the reality of ancient oceans or water in active gullies but do see evidence of fluvial modification of geologically recent mid-latitude gullies and equatorial impact craters.

The Gaussian Generalized Born model: application to small molecules

This work presents a Generalized Born model for the computation of the electrostatic component of solvation energies which is based on volume integration. An analytic masking function is introduced to remove Coulombic singularities. This approach leads to analytic formulae for the computation of Born radii, which are differentiable to arbitrary order, and computationally straightforward to implement.

Artificial composite bone as a model of human trabecular bone: the implant-bone interface

The use of artificial bones in implant testing has become popular due to their low variability and ready availability. However, friction coefficients, which are critical to load transfer in uncemented implants, have rarely been compared between human and artificial bone, particularly for wet and dry conditions. In this study, the static and dynamic friction coefficients for four commercially used titanium surfaces (polished, Al(2)O(3) blasted, plasma sprayed, beaded) acting on the trabecular component of artificial bones (Sawbones) were compared to those for human trabecular bone. Artificial bones were tested in dry and wet conditions and normal interface stress was varied (0.25, 0.5, 1.0MPa). Friction coefficients were mostly lower for artificial bones than real bone. In particular, static friction coefficients for the dry polished surface were 20% of those for real bone and 42-61% for the dry beaded surface, with statistical significance (alpha<0.05). Less marked differences were observed for dynamic friction coefficients. Significant but non-systematic effects of normal stress or wet/dry condition on friction coefficients were observed within each surface type. These results indicate that the use of artificial bone models for pre-clinical implant testing that rely on interface load transfer with trabecular bone for mechanical integrity can be particularly sensitive to surface finish and lubrication conditions.

Assessment of Mars Exploration Rover landing site predictions

Comprehensive analyses of remote sensing data during the three-year effort to select the Mars Exploration Rover landing sites at Gusev crater and at Meridiani Planum correctly predicted the atmospheric density profile during entry and descent and the safe and trafficable surfaces explored by the two rovers. The Gusev crater site was correctly predicted to be a low-relief surface that was less rocky than the Viking landing sites but comparably dusty. A dark, low-albedo, flat plain composed of basaltic sand and haematite with very few rocks was expected and found at Meridiani Planum. These results argue that future efforts to select safe landing sites based on existing and acquired remote sensing data will be successful. In contrast, geological interpretations of the sites based on remote sensing data were less certain and less successful, which emphasizes the inherent ambiguities in understanding surface geology from remotely sensed data and the uncertainty in predicting exactly what materials will be available for study at a landing site.

The Opportunity Rover's Athena science investigation at Meridiani Planum, Mars

The Mars Exploration Rover Opportunity has investigated the landing site in Eagle crater and the nearby plains within Meridiani Planum. The soils consist of fine-grained basaltic sand and a surface lag of hematite-rich spherules, spherule fragments, and other granules. Wind ripples are common. Underlying the thin soil layer, and exposed within small impact craters and troughs, are flat-lying sedimentary rocks. These rocks are finely laminated, are rich in sulfur, and contain abundant sulfate salts. Small-scale cross-lamination in some locations provides evidence for deposition in flowing liquid water. We interpret the rocks to be a mixture of chemical and siliciclastic sediments formed by episodic inundation by shallow surface water, followed by evaporation, exposure, and desiccation. Hematite-rich spherules are embedded in the rock and eroding from them. We interpret these spherules to be concretions formed by postdepositional diagenesis, again involving liquid water.

The Spirit Rover's Athena science investigation at Gusev Crater, Mars

The Mars Exploration Rover Spirit and its Athena science payload have been used to investigate a landing site in Gusev crater. Gusev is hypothesized to be the site of a former lake, but no clear evidence for lacustrine sedimentation has been found to date. Instead, the dominant lithology is basalt, and the dominant geologic processes are impact events and eolian transport. Many rocks exhibit coatings and other characteristics that may be evidence for minor aqueous alteration. Any lacustrine sediments that may exist at this location within Gusev apparently have been buried by lavas that have undergone subsequent impact disruption.

Localization and physical properties experiments conducted by Spirit at Gusev Crater

The precise location and relative elevation of Spirit during its traverses from the Columbia Memorial station to Bonneville crater were determined with bundle-adjusted retrievals from rover wheel turns, suspension and tilt angles, and overlapping images. Physical properties experiments show a decrease of 0.2% per Mars solar day in solar cell output resulting from deposition of airborne dust, cohesive soil-like deposits in plains and hollows, bright and dark rock coatings, and relatively weak volcanic rocks of basaltic composition. Volcanic, impact, aeolian, and water-related processes produced the encountered landforms and materials.

Pancam multispectral imaging results from the Spirit Rover at Gusev Crater

Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces and rock regions exposed by brushing or grinding show near-infrared spectral signatures consistent with the presence of mafic silicates such as pyroxene or olivine. Atmospheric observations show a steady decline in dust opacity during the mission, and astronomical observations captured solar transits by the martian moons, Phobos and Deimos, as well as a view of Earth from the martian surface.

Wind-related processes detected by the Spirit Rover at Gusev Crater, Mars

Wind-abraded rocks, ripples, drifts, and other deposits of windblown sediments are seen at the Columbia Memorial Station where the Spirit rover landed. Orientations of these features suggest formative winds from the north-northwest, consistent with predictions from atmospheric models of afternoon winds in Gusev Crater. Cuttings from the rover Rock Abrasion Tool are asymmetrically distributed toward the south-southeast, suggesting active winds from the north-northwest at the time (midday) of the abrasion operations. Characteristics of some rocks, such as a two-toned appearance, suggest that they were possibly buried and exhumed on the order of 5 to 60 centimeters by wind deflation, depending on location.

Surficial Deposits at Gusev Crater Along Spirit Rover Traverses

The Mars Exploration Rover Spirit has traversed a fairly flat, rock-strewn terrain whose surface is shaped primarily by impact events, although some of the landscape has been altered by eolian processes. Impacts ejected basaltic rocks that probably were part of locally formed lava flows from at least 10 meters depth. Some rocks have been textured and/or partially buried by windblown sediments less than 2 millimeters in diameter that concentrate within shallow, partially filled, circular impact depressions referred to as hollows. The terrain traversed during the 90-sol (martian solar day) nominal mission shows no evidence for an ancient lake in Gusev crater.

Pancam multispectral imaging results from the Spirit Rover at Gusev Crater

Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces and rock regions exposed by brushing or grinding show near-infrared spectral signatures consistent with the presence of mafic silicates such as pyroxene or olivine. Atmospheric observations show a steady decline in dust opacity during the mission, and astronomical observations captured solar transits by the martian moons, Phobos and Deimos, as well as a view of Earth from the martian surface.

Personal accounts of the role of God in health and illness among older rural African American and White residents

This paper addresses how older rural residents view the relationship between God and both health and illness. We employed semi-structured interviews and qualitative analytical strategies with 15 African Americans residing in predominantly African American communities and 13 Whites living in nearby predominantly White communities, in order to identify similarities and differences in views about a divine other's roles in health and illness. African Americans were more likely than Whites to describe their religious lives in personal terms, in ways suggesting there is a set of religious truths that do not require further investigation or analysis, and in a manner indicating that religious belief permeated their lives. They were also more likely to describe specific role expectations for God in health and illness. The results point to the substantial cultural diversity that exists in small rural areas, and to the need for health care workers to be sensitive to the health-related religious beliefs of patients.

Extracting material parameters from x-ray attenuation: a CT feasibility study using kilovoltage synchrotron x-rays incident upon low atomic number absorbers

The work reported here is a feasibility study of the extraction of material parameters from measurements of the linear x-ray attenuation coefficient of low atomic number absorbers. Computed tomography (CT) scans of small samples containing several liquids and solids were carried out with synchrotron radiation at the Australian National Beamline Facility (BL 20B) in Japan. Average values of the x-ray linear attenuation coefficient were extracted for each material for x-ray energies ranging from 11 keV to 20.5 keV. The electron density was estimated by applying results derived from a parametrization of the x-ray linear attenuation coefficient first developed by Jackson and Hawkes and extended for this work. Average estimates for the electron density of triethanolamine and acetic acid were made to within +5.3% of the actual value. Other materials examined included furfuraldehyde, perspex and teflon, for which average estimates of the electron density were less than 10% in excess of the calculated value.

A report of a rare immediate reaction after ingestion of acetaminophen

BACKGROUND

Acetaminophen hypersensitivity is rare and, when seen, is usually in association with sensitivity to nonsteroidal anti-inflammatory drugs.

METHODS

This is a case report of an immediate reaction to acetaminophen, confirmed by a drug challenge, in a subject who tolerated ibuprofen.

RESULTS

After an oral challenge with 50 mg of acetaminophen, the subject had generalized pruritus, urticaria, and dyspnea.

CONCLUSIONS

This patient demonstrates a rare but potentially severe reaction to acetaminophen that may occur in patients who are not otherwise sensitive to other nonsteroidal anti-inflammatory drugs.

Spina bifida outcome: a 25-year prospective

BACKGROUND

Open spina bifida is the most complex congenital abnormality compatible with long-term survival. This report outlines the 20- to 25-year outcome for our original cohort of patients with a myelomeningocele treated in a nonselective, prospective manner.

METHODS

Of the initial 118 children, 71 patients were available for our most recent review. Nineteen patients have been lost to follow-up and 28 patients have died. Data were collected on: motor level, shunt status, education/employment, seizure history, mobility, bladder/bowel continence, tethered cord, scoliosis, latex allergy, posterior cervical decompression, tracheostomy and/or gastrostomy tube.

RESULTS

Mortality (24%) continues to climb into young adulthood. Eighty-six percent of the cohort have cerebrospinal fluid diversion, with 95% having undergone at least one shunt revision. Thirty-two percent have undergone a tethered cord release, with 97% having an improvement or stabilization in their preoperative symptoms. Forty-nine percent have scoliosis, with 43% eventually requiring a spinal fusion. Sixteen patients (23%) have had at least one seizure. Eighty-five percent are attending or have graduated from high school and/or college. More than 80% of young adults have social bladder continence. Approximately 1/3 of patients are allergic to latex, with 6 patients having experienced a life-threatening reaction.

CONCLUSION

At least 75% of children born with a myelomeningocele can be expected to reach their early adult years. Late deterioration is common. One of the greatest challenges in medicine today is establishing a network of care for these adults with spina bifida.

Molecular pharmacology of second-generation antihistamines

Histamine was the first allergic mediator identified in the early part of this century. It has three defined receptors, but most effects of histamine in allergic reactions are through the H1 receptor. The first H1 antagonists were introduced into clinical use in the late 1940s, and drugs of this class are still the preferred initial choice for management of allergic rhinitis and urticaria. The first-generation drugs were characterized by nonspecific binding to many receptors and penetration of the blood-brain barrier, resulting in multiple side effects. Within the central nervous system (CNS), interference with normal histamine binding to the H1 receptor is associated with drowsiness and psychomotor impairment. The second-generation drugs have a much improved benefit/adverse effect profile, largely based on greater potency, receptor specificity, and lower CNS penetration. The potency of antihistamines for blocking H1 receptors can be compared by their inhibition of the cutaneous wheal and flare response to histamine. These drugs seem to have additional antiallergic properties related to blockade of mediator release and interference with cellular recruitment and activation. Clinical trials comparing the efficacy of antihistamines in rhinitis and asthma are reviewed. Recent studies have explored the potential of antihistamines to prevent the progression of allergy and their enhanced efficacy when combined with leukotriene antagonists.

Eotaxin induces degranulation and chemotaxis of eosinophils through the activation of ERK2 and p38 mitogen-activated protein kinases

Eotaxin and other CC chemokines acting via CC chemokine receptor-3 (CCR3) are believed to play an integral role in the development of eosinophilic inflammation in asthma and allergic inflammatory diseases. However, little is known about the intracellular events following agonist binding to CCR3 and the relationship of these events to the functional response of the cell. The objectives of this study were to investigate CCR3-mediated activation of the mitogen-activated protein (MAP) kinases extracellular signal-regulated kinase-2 (ERK2), p38, and c-jun N-terminal kinase (JNK) in eosinophils and to assess the requirement for MAP kinases in eotaxin-induced eosinophil cationic protein (ECP) release and chemotaxis. MAP kinase activation was studied in eotaxin-stimulated eosinophils (more than 97% purity) by Western blotting and immune-complex kinase assays. ECP release was measured by radioimmunoassay. Chemotaxis was assessed using Boyden microchambers. Eotaxin (10(-11) to 10(-7) mol/L) induced concentration-dependent phosphorylation of ERK2 and p38. Phosphorylation was detectable after 30 seconds, peaked at about 1 minute, and returned to baseline after 2 to 5 minutes. Phosphorylation of JNK above baseline could not be detected. The kinase activity of ERK2 and p38 paralleled phosphorylation. PD980 59, an inhibitor of the ERK2-activating enzyme MEK (MAP ERK kinase), blocked phosphorylation of ERK2 in a concentration-dependent manner. The functional relevance of ERK2 and p38 was studied using PD98 059 and the p38 inhibitor SB202 190. PD98 059 and SB202 190 both caused inhibition of eotaxin-induced ECP release and chemotaxis. We conclude that eotaxin induces a rapid concentration-dependent activation of ERK2 and p38 in eosinophils and that the activation of these MAP kinases is required for eotaxin-stimulated degranulation and directed locomotion. (Blood. 2000;95:1911-1917)

Impact of cetirizine on the burden of allergic rhinitis

OBJECTIVE

The goals of this article include the reporting of the epidemiology, economic and medical impact of allergic rhinitis. In addition, the pharmacology and clinical profile of the therapeutic agent cetirizine are reviewed.

DATA SOURCES

A detailed literature search was conducted. References are limited to the English language and human subjects and tissues. Studies considered relevant and important over the past 20 years are highlighted.

STUDY SELECTION

Prevalence and morbidity data were chosen from more recent assessments. Because cetirizine is a relatively new compound, studies from the past several years from peer-reviewed journals have been emphasized.

RESULTS

Allergic rhinitis affects between 15% and 25% of the US general population. It shares common pathophysiologic mechanisms with conjunctivitis and asthma and predisposes to nasal infections, otitis media, sinusitis, nasal polyposis, and orthodontic malocclusions. Direct medical care costs amount to up to 3 billion dollars every year. In addition, the quality of life of affected individuals is substantially compromised. Cetirizine is a potent H1-receptor antagonist and has anti-inflammatory properties. It does not interact with concomitantly administered medications, has no cardiac adverse effects, and does not appear to be associated with teratogenicity. Impairment of CNS function is comparable to other low-sedating antihistamines at the recommended dose of 10 mg daily for adults. Its clinical efficacy for allergic respiratory diseases has been established in numerous trials.

CONCLUSIONS

Allergic rhinitis causes considerable suffering. Cetirizine, with a fine risk-benefit ratio, can be a most valuable therapeutic option.

A double-blind, single-dose, crossover comparison of cetirizine, ebastine, epinastine, fexofenadine, terfenadine, and loratadine versus placebo: suppression of histamine-induced wheal and flare response for 24 h in healthy male subjects

BACKGROUND

New H1-antagonists have become available, but there has been no comparison of their potency for inhibiting histamine in the skin.

METHODS

Cetirizine 10 mg, ebastine 10 mg, epinastine 20 mg, fexofenadine 60 mg, terfenadine 60 mg, loratadine 10 mg, or placebo was given to 14 healthy male volunteers in a double-blind, crossover randomized manner. Inhibition of the wheal and flare response to epicutaneous histamine phosphate (100 mg/ml) challenge was measured at 0, 0.5, 1, 2, 4, 6, 8, 10, 12, and 24 h after doses.

RESULTS

Epinastine inhibited the wheal and flare after 30 min. Cetirizine commenced acting at 1 h and was superior to other treatments. Ebastine was no better than placebo until 4 h, but was efficacious thereafter until 24 h. Terfenadine induced potent inhibition after 1 h and was superior to its metabolite fexofenadine. Loratadine was the least potent inhibitor. Inhibition of the flare response paralleled the patterns seen for wheals. The rank order for area under the curve (0-24 h) was cetirizine, epinastine, terfenadine, ebastine, fexofenadine, loratadine, and placebo.

CONCLUSIONS

The inhibition of histamine effects in the skin may be useful in predicting the clinical utility of newly introduced antihistamines in treating allergic disorders.

Admission-related migration by older nursing home residents

OBJECTIVE

To examine recent admissions of older adults to intermediate care facilities in order to identify the factors associated with whether the individual originated in another county, a non-adjacent county, and another state.

METHODS

Employing a conceptual framework based upon migration theory and the long-term care decision process and a data set derived from multiple sources, logistic regression was used to examine whether characteristics of the county of residence prior to admission, the admission facility, and the individual are significant net predictors of the three types of mobility. Separate analyses were conducted for married and unmarried individuals.

RESULTS

The analytical models tended to have relatively good fit but only moderate predictive accuracy. In general, persons on Medicaid payment status were more likely to move to another county and to a non-adjacent county, whereas Medicaid payment was associated with a lower likelihood of migrating to Virginia from another state. Individuals originating in counties with higher bed rates had lower rates of migration to another county and non-adjacent county, whereas those from counties with higher occupancy rates were more likely to leave their county of origin.

CONCLUSION

Examination of factors associated with the distance and patterns of nursing home mobility improves our understanding of the nursing home selection process and helps to illuminate the impact of public policy, market forces, and nursing home staff on who goes where to be admitted to a nursing home.

Bronchial asthma: update on the revised guidelines for diagnosis and management

Bronchial asthma is a chronic disease with variable airway narrowing, respiratory distress, hyper-responsiveness and inflammation. The morbidity and mortality are increasing despite availability of newer diagnostic and therapeutic strategies. The National Institutes of Health recently issued revised guidelines for disease management. The keys to improved care include earlier recognition of the illness, reduced exposure to triggers, careful monitoring, greater use of long-term control medications and improved patient education.

Unstimulated basophils in atopic and nonatopic subjects express intracellular interleukin-4: detection by flow cytometry

BACKGROUND

IgE-stimulated cultured basophils from atopic subjects are capable of secreting interleukin-4 (IL-4). We describe a flow-cytometric technique which identified intracellular IL-4 in unstimulated basophils unseparated from peripheral blood mononuclear cells (PBMC) in both atopic (AT) and nonatopic (NC) volunteers.

METHODS

Freshly isolated PBMC were fixed in 4% paraformaldehyde (PFA). Surface staining with 22E7, a noncompetitive anti-FcepsilonRI-alpha antibody, allowed identification of basophils. Permeabilization by 0.1% saponin allowed staining of intracellular cytokines with specific monoclonal antibodies (mAbs). Two series of experiments utilizing different protocols and anticytokine mAbs were performed. The first protocol required a two-stage fluorochrome staining technique. The availability of fluorochrome-conjugated mAbs allowed a simpler, one-stage labelling procedure for the second protocol.

RESULTS

With the first protocol, IL-4 (but not IFN-gamma), immunoreactivity was detectable in a majority (median 77%) of peripheral blood basophils from both AT and NC subjects (n=8). Basophil IL-4 immunoreactivity was again evident in experiment 2 but did not differ significantly between AT and NC subjects--either evaluated as percentage of IL-4+ basophils (AT median=66%, NC median=38.4%, P=0.41) or IL-4-specific mean fluorescence (AT median=0.85, NC median=0.3, P=0.07).

CONCLUSIONS

This simple technique allowed the study of intracellular cytokine expression in unstimulated blood basophils. It demonstrated constitutive basophil expression of IL-4 (but not IFN-gamma) in all subjects, with no significant increases in atopics.

Increased expression of high affinity IgE (FcepsilonRI) receptor-alpha chain mRNA and protein-bearing eosinophils in human allergen-induced atopic asthma

FcepsilonRI receptors play an important role in allergen-induced mediator release and antigen presentation by mast cells, basophils, and monocyte/macrophages in atopic disorders. The expression of FcepsilonRI by tissue eosinophils in atopic asthma after allergen challenge has not been established. For this reason we attempted to identify mRNA and protein product + FcepsilonRIalpha eosinophils in cytospins made from bronchoalveolar lavage (BAL) from atopic asthmatics (n = 9) and nonatopic normal subjects (n = 4) 24 h after segmental challenge with allergen or diluent. Messenger RNA for FcepsilonRIalpha was determined using in situ hybridization and FcepsilonRIalpha protein expression by immunocytochemistry using a mouse monoclonal antibody 22E7. Colocalization of FcepsilonRIalpha receptors to eosinophils was performed using chromotrope 2R. When compared with a control challenge, segmental challenge with Dermatophagoides pteronyssinus induced significant BAL eosinophilia (p = 0.007). The total number of BAL FcepsilonRIalpha mRNA and protein-positive cells also increased in asthmatics, median values 2 (0.7-7.2) and 11.5 (0.6-65.0) x 10(6) cells (p = 0.02) and 0 (0-0.3 x 10(6)) and 3.1 x 10(6) (0.45 - 162.5 x 10(6)) cells (p = 0.007), respectively, for mRNA and protein. Net increases in FcepsilonRIalpha+ cells correlated with the net increases in BAL eosinophils (r = 0.98, p = 0.0001 for mRNA and r = 0.72, p = 0.02 for protein). Colocalization studies with chromotrope 2R revealed that only 4% of FcepsilonRIalpha+ cells were eosinophils after control challenge and, in contrast, 85 to 95% of FcepsilonRIalpha+ cells were eosinophils after allergen. There were no differences in the numbers of FcepsilonRIalpha+ cells or eosinophils in normal control subjects. Our results demonstrated that local endobronchial allergen provocation in atopic asthmatics results in increased synthesis and expression of FcepsilonRIalpha predominantly on BAL eosinophils.