Nasal and pharyngeal eosinophil peroxidase levels in adults with poorly controlled asthma correlate with sputum eosinophilia.

The objective of the study was to compare nasal, pharyngeal, and sputum eosinophil peroxidase (EPX) levels with induced sputum eosinophil percentage in 10 adults with poorly controlled asthma and 10 normal controls. EPX was measured using an ELISA and normalized for grams of protein for nasal and pharynx specimens and for mL-gram of protein for sputum. Sputum EPX levels were statistically different between asthma and control subjects (P = 0.024). EPX levels measured in the nasal and pharyngeal swab samples derived from the same patients were also different between asthma and control subjects, each displaying a high degree of significance (P = 0.002). Spearman's correlation coefficients for nasal EPX and pharyngeal EPX levels compared to induced sputum eosinophil percentage were 0.81 (P = 0.0007) and 0.78 (P = 0.0017), respectively. Thus, there is a strong association in a given patient between both nasal and pharyngeal EPX levels and the eosinophil percentage of induced sputum.

Differential activation of airway eosinophils induces IL-13-mediated allergic Th2 pulmonary responses in mice.

BACKGROUND: Eosinophils are hallmark cells of allergic Th2 respiratory inflammation. However, the relative importance of eosinophil activation and the induction of effector functions such as the expression of IL-13 to allergic Th2 pulmonary disease remain to be defined. METHODS: Wild-type or cytokine-deficient (IL-13(-/-) or IL-4(-/-) ) eosinophils treated with cytokines (GM-CSF, IL-4, IL-33) were adoptively transferred into eosinophil-deficient recipient mice subjected to allergen provocation using established models of respiratory inflammation. Allergen-induced pulmonary changes were assessed. RESULTS: In contrast to the transfer of untreated blood eosinophils to the lungs of recipient eosinophil deficient mice, which induced no immune/inflammatory changes either in the lung or in the lung draining lymph nodes (LDLN), pretreatment of blood eosinophils with GM-CSF prior to transfer elicited trafficking of these eosinophils to LDLN. In turn, these LDLN eosinophils elicited the accumulation of dendritic cells and CD4(+) T cells to these same LDLNs without inducing pulmonary inflammation. However, exposure of eosinophils to GM-CSF, IL-4, and IL-33 prior to transfer induced not only immune events in the LDLN, but also allergen-mediated increases in airway Th2 cytokine/chemokine levels, the subsequent accumulation of CD4(+) T cells as well as alternatively activated (M2) macrophages, and the induction of pulmonary histopathologies. Significantly, this allergic respiratory inflammation was dependent on eosinophil-derived IL-13, whereas IL-4 expression by eosinophils had no significant role. CONCLUSION: The data demonstrate the differential activation of eosinophils as a function of cytokine exposure and suggest that eosinophil-specific IL-13 expression by activated cells is a necessary component of the subsequent allergic Th2 pulmonary pathologies.

Re-defining the unique roles for eosinophils in allergic respiratory inflammation.

The role of eosinophils in the progression and resolution of allergic respiratory inflammation is poorly defined despite the commonality of their presence and in some cases their use as a biomarker for disease severity and/or symptom control. However, this ambiguity belies the wealth of insights that have recently been gained through the use of eosinophil-deficient/attenuated strains of mice that have demonstrated novel immunoregulatory and remodelling/repair functions for these cells in the lung following allergen provocation. Specifically, studies of eosinophil-deficient mice suggest that eosinophils contribute to events occurring in the lungs following allergen provocation at several key moments: (i) the initiating phase of events leading to Th2-polarized pulmonary inflammation, (ii) the suppression Th1/Th17 pathways in lung-draining lymph nodes, (iii) the recruitment of effector Th2 T cells to the lung, and finally, (iv) mechanisms of inflammatory resolution that re-establish pulmonary homoeostasis. These suggested functions have recently been confirmed and expanded upon using allergen provocation of an inducible eosinophil-deficient strain of mice (iPHIL) that demonstrated an eosinophil-dependent mechanism(s) leading to Th2 dominated immune responses in the presence of eosinophils in contrast to neutrophilic as well as mixed Th1/Th17/Th2 variant phenotypes in the absence of eosinophils. These findings highlighted that eosinophils are not exclusively downstream mediators controlled by T cells, dendritic cells (DC) and/or innate lymphocytic cells (ILC2). Instead, eosinophils appear to be more aptly described as significant contributors in complex interrelated pathways that lead to pulmonary inflammation and subsequently promote resolution and the re-establishment of homoeostatic baseline. In this review, we summarize and put into the context the evolving hypotheses that are now expanding our understanding of the roles eosinophils likely have in the lung following allergen provocation.

Eosinophil activities modulate the immune/inflammatory character of allergic respiratory responses in mice.

BACKGROUND: The importance and specific role(s) of eosinophils in modulating the immune/inflammatory phenotype of allergic pulmonary disease remain to be defined. Established animal models assessing the role(s) of eosinophils as contributors and/or causative agents of disease have relied on congenitally deficient mice where the developmental consequences of eosinophil depletion are unknown. METHODS: We developed a novel conditional eosinophil-deficient strain of mice (iPHIL) through a gene knock-in strategy inserting the human diphtheria toxin (DT) receptor (DTR) into the endogenous eosinophil peroxidase genomic locus. RESULTS: Expression of DTR rendered resistant mouse eosinophil progenitors sensitive to DT without affecting any other cell types. The presence of eosinophils was shown to be unnecessary during the sensitization phase of either ovalbumin (OVA) or house dust mite (HDM) acute asthma models. However, eosinophil ablation during airway challenge led to a predominantly neutrophilic phenotype (>15% neutrophils) accompanied by allergen-induced histopathologies and airway hyper-responsiveness in response to methacholine indistinguishable from eosinophilic wild-type mice. Moreover, the iPHIL neutrophilic airway phenotype was shown to be a steroid-resistant allergic respiratory variant that was reversible upon the restoration of peripheral eosinophils. CONCLUSIONS: Eosinophil contributions to allergic immune/inflammatory responses appear to be limited to the airway challenge and not to the sensitization phase of allergen provocation models. The reversible steroid-resistant character of the iPHIL neutrophilic airway variant suggests underappreciated mechanisms by which eosinophils shape the character of allergic respiratory responses.

Eosinophil peroxidase in sputum represents a unique biomarker of airway eosinophilia.

BACKGROUND: Sputum eosinophilia has been shown to be a predictor of response to anti-eosinophil therapies in patients with airway diseases. However, quantitative cell counts and differentials of sputum are labor intensive. The objective of this study was to validate a novel ELISA-based assay of eosinophil peroxidase (EPX) in sputum as a rapid and reliable marker of airway eosinophils. METHODS: The utility of EPX-based ELISA as an eosinophil-specific assay was achieved through comparisons with sputum eosinophil differential counts in freshly prepared and archived patient samples from a variety of clinical settings. RESULTS: EPX levels in sputum correlated with eosinophil percentage (r(s) = 0.84) in asthma patients with varying degrees of airway eosinophilia. Significantly, unlike assays of other eosinophil granule proteins (e.g., ECP and EDN), which often detect the presence of these proteins even in asthma patients with neutrophilic bronchitis, EPX-based ELISA levels are not increased in this subset of asthma patients or in COPD patients lacking evidence of an airway eosinophilia. Moreover, sputum EPX was a surrogate marker of airway eosinophilia in other patient studies (e.g., allergen inhalation and treatment trials the anti-(IL-5) therapeutic Mepolizumab™). Finally, EPX levels in cytocentrifuged prepared sputum supernatants correlated with those from rapidly prepared noncentrifuged filtrates of sputum (r(s) = 0.94). CONCLUSION AND CLINICAL IMPLICATION: EPX-based ELISA is a valid, reliable, repeatable, and specific surrogate marker of eosinophils and/or eosinophil degranulation in the sputum of respiratory patients. The novel EPX assay is a valid and reproducible eosinophil-specific assay that can potentially be developed into a point-of-care assessment of eosinophil activity in airway secretions.

CD8 surface levels alter the fate of alpha/beta T cell receptor-expressing thymocytes in transgenic mice.

The mature T cell receptor (TCR) repertoire is established on the basis of discriminative events involving binding of the TCR alpha and beta chains and CD4 or CD8 on immature thymocytes to major histocompatibility complex (MHC)/self-peptide complexes expressed in the thymus. To ask whether the strength of the interaction between a CD8/TCR complex and a MHC/self-peptide ligand plays a pivotal role in deciding the fate of a maturing thymocyte, we generated lines of transgenic mice that express distinct and elevated levels of CD8 alpha, approximately 2, 3, and 6-10 times. These lines were then crossed to a transgenic line expressing the class I-restricted TCR, 2C. We found that thymocytes expressing the 2C TCR in combination with the highest levels of CD8 were deleted on the H-2 Kb background that is normally positively selecting for the 2C TCR. In contrast, thymocytes coexpressing the 2C TCR and moderately elevated levels of CD8 were selected for maturation. These results demonstrate directly that CD8 levels can affect the developmental fate of a maturing thymocyte and argue in support of an affinity model for thymocyte selection.

Interleukin-5 expression in the lung epithelium of transgenic mice leads to pulmonary changes pathognomonic of asthma.

We have generated transgenic mice that constitutively express murine interleukin (IL)-5 in the lung epithelium. Airway expression of this cytokine resulted in a dramatic accumulation of peribronchial eosinophils and striking pathologic changes including the expansion of bronchus-associated lymphoid tissue (BALT), goblet cell hyperplasia, epithelial hypertrophy, and focal collagen deposition. These changes were also accompanied by eosinophil infiltration of the airway lumen. In addition, transgenic animals displayed airway hyperresponsiveness to methacholine in the absence of aerosolized antigen challenge. These findings demonstrate that lung-specific IL-5 expression can induce pathologic changes characteristic of asthma and may provide useful models to evaluate the efficacy of potential respiratory disease therapies or pharmaceuticals.

Eosinophils in health and disease: the LIAR hypothesis.

Discussions of eosinophils are often descriptions of end-stage effector cells with destructive capabilities mediated predominantly by released cytotoxic cationic granule proteins. Moreover, eosinophils in the medical literature are invariably associated with the pathologies linked with helminth infections or allergic diseases such as asthma. This has led to an almost fatalist view of eosinophil effector functions and associated therapeutic strategies targeting these cells that would make even William of Ockham proud - eosinophil effector functions have physiological consequences that increase patient morbidity/mortality and 'the only good eosinophils are dead eosinophils'. Unfortunately, the strengths of dogmas are also their greatest weaknesses. Namely, while the repetitive proclamation of dogmatic concepts by authoritative sources (i.e. reviews, meeting proceedings, textbooks, etc.) builds consensus within the medical community and lower the entropies surrounding difficult issues, they often ignore not easily explained details and place diminished importance on alternative hypotheses. The goal of this perspective is twofold: (i) we will review recent observations regarding eosinophils and their activities as well as reinterpret earlier data as part of the synthesis of a new paradigm. In this paradigm, we hypothesize that eosinophils accumulate at unique sites in response to cell turnover or in response to local stem cell activity(ies). We further suggest that this accumulation is part of one or more mechanisms regulating tissue homeostasis. Specifically, instead of immune cells exclusively mediating innate host defence, we suggest that accumulating tissue eosinophils are actually regulators of Local Immunity And/or Remodeling/Repair in both health and disease - the LIAR hypothesis; (ii) we want to be inflammatory (pun intended!) and challenge the currently common perspective of eosinophils as destructive end-stage effector cells. Our hope is to create more questions than we answer and provoke everyone to spend countless hours simply to prove us wrong!

Expression of IL-5 alters bone metabolism and induces ossification of the spleen in transgenic mice.

We have developed a transgenic mouse line, NJ.1638, which expresses high levels of IL-5 from T cells, with profound hematological consequences. Eosinophils comprise more than 60% of circulating white blood cells in these animals, with the total peripheral white blood cell counts increasing more than 40-fold relative to wild-type littermates. This extraordinary proliferative capacity is sustained by expanded sites of extramedullary hematopoiesis and is accompanied by multifocal, ectopic bone formation in the spleen. Histology of the splenic nodules revealed the presence of osteoid matrices and osteocytes trapped within mineralized trabecular plates. In addition, polarized light microscopy of calcified tissue sections revealed both woven bone and areas of organized lamellar bone. Morphometric assessments demonstrated that both the growth and mineralization of splenic bone occurred at rates nearly an order of magnitude higher than in skeletal bone. Skeletal bone metabolic parameters were also perturbed. We also observed heterotopic ossification of the spleen and perturbation of skeletal bone homeostasis following adoptive engraftment of transgenic marrow to wild-type recipients. These data suggest that IL-5 overexpression mediates bone formation through the mobilization of marrow-derived osteogenic progenitors and/or the inhibition of recruited osteoclasts.

Cloning of the murine eosinophil peroxidase gene (mEPO): characterization of a conserved subgroup of mammalian hematopoietic peroxidases.

The mouse eosinophil peroxidase (mEPO) gene was cloned by screening a random-primed bone marrow cDNA library at reduced criteria using a hEPO cDNA. An mEPO cDNA was subsequently used to isolate the mEPO gene from a lambda-genomic library. The mEPO gene displays a high degree of conservation with its human homologue: the transcription units are approximately the same size, conserve the relative size and position of the 12 exons associated with each gene, and at a nucleotide level the mouse and human EPO genes are 86% identical in the protein coding regions and 66% identical in the 3'-untranslated trailer regions. This strong conservation extends to the encoded proteins which show approximately 90% amino acid identity. Expression of the mEPO gene is restricted to tissues containing eosinophil progenitor cells (e.g., bone marrow and spleen), a pattern similar to the expression of another murine eosinophil granule protein, major basic protein.

Identification of a new murine eosinophil major basic protein (mMBP) gene: cloning and characterization of mMBP-2.

We have identified a new eosinophil major basic protein gene family member in the mouse and have given it the designation murine major basic protein-2 (mMBP-2). The gene was initially characterized as a unique expressed sequence tag (EST) clone having significant identity to the previously recognized member of this gene family, mMBP-1. The EST was used to screen and isolate mMBP-2 from a bone marrow cDNA library. In addition, a genomic clone of mMBP-2 was isolated and this gene was shown to be physically linked to within 100 kb of mMBP-1 on the central region of mouse chromosome 2. Progressive similarity alignment of the deduced mMBP-2 open reading frame demonstrates the apparent conservation of the "pre-pro-mature" protein structure found in the other known mammalian MBPs. Mature mMBP-2 maintains the cationic nature associated with these proteins with a predicted pI of 9.95. However, unlike the human MBPs, which display a three orders of magnitude charge difference [hMBP-1 (pI 11.4) vs. hMBP-2 (pI 8.7)], mMBP-2 is only slightly less cationic than mMBP-1 (pI 10.5). Expression studies demonstrate that transcription of the mMBP-2 gene parallels mMBP-1 and is confined to hematopoietic compartments engaged in eosinophilopoiesis. Moreover, using mMBP-1 knockout mice and immunohistochemistry with an antisera that recognizes both mMBP-1 and -2, we demonstrate that mMBP-2 protein expression is restricted to eosinophil lineage-committed cells.

Beneficial effect of chromium supplementation on serum triglyceride levels in NIDDM.

OBJECTIVE: To investigate the effect of chromium picolinate supplementation on the lipid profile of the predominantly Hispanic population of non-insulin-dependent diabetes mellitus (NIDDM) patients in San Antonio, Texas. RESEARCH DESIGN AND METHODS: A prospective, double-blind, placebo-controlled, crossover study was performed on 14 men and 16 women. Initially, each patient was randomly assigned to receive either chromium picolinate or placebo for 2 months. This initial treatment phase was followed by a 2-month washout period. Subjects were then crossed-over and received the alternate capsule for an additional 2 months. Fasting blood glucose, HbA1c, and serum lipids were compared at the end of each treatment phase. RESULTS: Twenty-eight of the originally enrolled 30 patients completed the study. There were no adverse reactions to chromium reported. There were no differences noted between the control and chromium-treated subjects in glucose control, high-density lipoprotein cholesterol levels, or low-density lipoprotein cholesterol levels. Triglyceride (TG) levels were reduced significantly (17.4%; P < 0.05) during the 2 months of chromium supplementation. CONCLUSIONS: Ours is the first report of a significant reduction in serum TGs in a group of NIDDM patients treated with chromium. The low cost and excellent safety profile of chromium make it an attractive lipid-lowering agent for this population. Long-term studies are needed to determine if the short-term changes in plasma lipids can be sustained.

Soluble P-selectin glycoprotein ligand 1 inhibits ocular inflammation in a murine model of allergy.

PURPOSE: To assess the anti-inflammatory modality of a soluble extracellular form of P-selectin glycoprotein ligand 1 (sPSGL-1) in a mouse model of ocular allergic response. METHODS: Potential anti-inflammatory effects of sPSGL-1 were investigated in SWR/J mice sensitized by topical application of short ragweed pollen to the nasal mucosa followed by a challenge of the ocular mucosa with the same allergen. Five experimental groups were included in these studies: A, mice neither sensitized nor challenged with pollen (control group 1); B, animals sensitized but not challenged (control group 2); C, animals not sensitized but challenged (control group 3); D, animals sensitized and challenged; and E, sensitized animals treated with sPSGL-1 before pollen challenge. All experimental groups were evaluated for gross morphologic ocular changes, and histologic assessments were made to determine the onset/progression of inflammatory reactions and to look for evidence of eosinophil infiltration. RESULTS: Mice sensitized and challenged with pollen developed clinical signs consistent with human allergic conjunctivitis. These signs correlate with histologic changes in the conjunctival epithelium and stroma (e.g., edema and extensive eosinophil infiltration). Moreover, the ocular changes also correlated with evidence of eosinophil degranulation. However, sensitized and challenged mice concurrently treated with sPSGL-1 displayed no inflammatory ocular changes associated with a ragweed-induced type-1 hypersensitivity reaction. The lack of ocular changes included the absence of histologic late-phase inflammatory changes of the conjunctiva and a 97% reduction in the induced eosinophil infiltrate. CONCLUSIONS: The antagonistic intervention of cell- cell interactions through the blockade of selectin-dependent leukocyte adhesion may offer novel therapeutic strategies to modulate inflammatory responses. The potent inhibitory effects on eosinophil recruitment and late-phase inflammation suggest a role for sPSGL-1 in the treatment of ocular allergic diseases.

Eosinophils are cellular targets of the novel uteroplacental heparin-binding cytokine decidual/trophoblast prolactin-related protein.

The uterus and placenta of the mouse and rat produce a member of the prolactin (PRL) family referred to as decidual/trophoblast PRL-related protein (d/tPRP). This cytokine/hormone has been hypothesized to regulate decidual cell activities needed for the establishment and maintenance of gestation. An alkaline phosphatase (AP)-tagging strategy was used to identify d/tPRP target cells. AP-d/tPRP bound to virtually all cells and tissues to which it was exposed, consistent with our earlier evidence that d/tPRP binds to heparin-containing molecules. Moreover, we found that co-incubation with heparin or pretreatment with heparitinase greatly decreased the binding of AP-d/tPRP to tissue sections. In addition, we observed that the AP-d/tPRP probe bound to the surface of Chinese hamster ovary (CHO) cells but not to heparan sulfate-deficient CHO-pgsD-677 cells. Potential unique non-heparin d/tPRP binding sites within mouse and rat uteroplacental tissues were identified by consecutively incubating sections with AP-d/tPRP followed by heparin. This strategy led to the identification of d/tPRP target cells associated with the uterus and the labyrinth zone of the chorioallantoic placenta. Within the uterus, d/tPRP specifically bound to eosinophils. d/tPRP-binding and eosinophil peroxidase activity were co-localized and showed similar patterns of distribution during the estrous cycle, pregnancy, and following hormonal manipulation. d/tPRP interactions with eosinophils were further demonstrated in the lung and intestine, with eosinophils isolated from the peritoneum, and in mice with generalized tissue eosinophilia. Collectively, these findings suggest that intercellular d/tPRP targeting is mediated through associations with heparin-containing molecules which help direct d/tPRP to specific interactions with eosinophils within the uterus and with the labyrinthine compartment of the chorioallantoic placenta.

A natural isolate of Pseudomonas maltophila which degrades aromatic sulfonic acids.

A natural isolate, designated BSA56, which was originally selected for growth with benzene sulfonic acid as sole carbon and energy source, was identified as a strain of Pseudomonas maltophila. Strain BSA56 grew on a wide range of aromatic sulfonic acids and was shown to release sulfite from benzene sulfonic acid and 2-naphthalene sulfonic acid. Although it also grew on toluene sulfonic acid and pyridine sulfonic acid, no significant sulfite release was observed with these substrates. Release of sulfite from benzene sulfonic acid was greatly promoted by the presence of glycerol. The ability to release sulfite was induced by growth in the presence of benzene sulfonic acid and was repressed almost entirely by substrates allowing rapid growth such as acetate. Strain BSA56 grew better at 30 degrees C than 37 degrees C on most aromatic substrates, but the reverse was true for most aromatic sulfonates. Several mutants of BSA56 were isolated with defects in benzoate, salicylate, or gentisate metabolism. However, all these mutants retained the ability to degrade the aromatic sulfonates.

Environmental monitoring of pesticides by immunoanalytical techniques: validation, current status, and future perspectives.

Reliable monitoring technology is an essential component of effective regulation and risk management of environmental contaminants such as pesticides. Most environmental monitoring and analysis is currently conducted using instrumental techniques such as gas-liquid chromatography (GLC) and liquid chromatography (LC). Immunoanalysis provides powerful monitoring techniques that have emerged in the last 3 decades. This paper shows they can deliver rapid, accurate, and relatively inexpensive analysis with high throughput and that have the capability to be field oriented. The technique is versatile in application and can be formatted to suit different purposes such as quantitative analysis or simple "yes/no" tests that are field-portable. While there is a range of opinion on the merits of immunoassays as an analytical tool for pesticides, we suggest that this technology is best considered as complementary to GLC and LC, extending the range of capability for field monitoring. Supporting this view, an increasing number of successful applications of immunoassays to monitoring have been reported in recent years. We also report here the implications of recent developments in the field of immunodiagnostics and their application to monitoring of environmental contaminants. We emphasise that, together with adequate validation by instrumental techniques, immunoassays provide monitoring services yielding realistic and comprehensive data for risk management, allowing decisions on appropriate action by various authorities to be made.

Airway eosinophilia in remission and progression of asthma: accumulation with a fast decline of FEV(1).

BACKGROUND: As it is unknown whether complete asthma remission or progression of asthma is associated with airway inflammation and remodeling, we assessed these characteristics in bronchial biopsies of relevant subsets of asthma patients. METHODS: Sputum and bronchial biopsies were obtained from asthma patients in remission (PC(20) histamine> 32 mg/ml, PC(20) AMP> 320 mg/ml) and from those with either a slow FEV(1) decline (< 30 ml/year) or fast decline (> 30 ml/year). Inflammatory cells and mediators were determined in sputum, inflammatory cells and aspects of airway remodeling in bronchial biopsies. RESULTS: Asthmatics in remission and asthma patients with a slow FEV(1) decline had a similar extent of airway inflammation and remodeling in sputum and bronchial biopsies. Asthma patients with a fast FEV(1) decline had high sputum eosinophil numbers. Moreover, FEV(1) decline (ml/year) correlated with sputum eosinophil numbers (Rs=0.51, p=0.003) and ECP levels (Rs=0.57, p=0.001). Airway remodeling, i.e. basement membrane thickness, correlated with sputum eosinophils (Rs=0.69, p<0.001), sputum ECP (Rs=0.46, p=0.018) and airway wall eosinophil numbers (Rs=0.49, p=0.002). CONCLUSIONS: Asthma, even when in remission, is accompanied by airway inflammation and remodeling. Data suggest that eosinophils are important in a subset of asthma patients by association to accelerated FEV(1) decline and change of basement membrane thickness.

Pulmonary T cells and eosinophils: coconspirators or independent triggers of allergic respiratory pathology?

Etiologic discussions of allergic respiratory pathology frequently engender rabid constituencies of pro-T cell or proeosinophil disciples, each claiming, often with religious fervor, the importance of their leukocyte. However, increasing evidence suggests that the exclusionary rhetoric from either camp is inadequate to explain many of the pathologic changes occurring in the lung. Data from both asthmatic patient and mouse models of allergic respiratory inflammation suggest that, in addition to cell-autonomous activities, T-cell and eosinophil interactions may be critical to the onset and progression of pulmonary pathology. These studies also suggest that T-lymphocyte subpopulations and eosinophils communicate by means of both direct cell-cell interactions and through the secretion of inflammatory signals. Collectively, the data support an expanded view of T-cell and eosinophil activities in the lung, including both immunoregulative activities and downstream effector functions impinging directly on lung function.

Effect of misoprostol (PGE1) on glucose metabolism in type-2-diabetic and control subjects.

In vitro and in vivo studies have demonstrated that prostaglandins of the E series enhance muscle glucose uptake. We examined the effect of acute misoprostol (PGE1) administration on whole body insulin-mediated glucose disposal, as well as the major intracellular pathways of glucose metabolism in type 2 diabetic (n = 10) and non-diabetic (n = 4) subjects. Each subject received two 240-min euglycaemic insulin (40 mU/m2/min) clamp studies with tritiated glucose and indirect calorimetry. During one of the insulin clamp studies, 200 microg of misoprostol was ingested at 90 and 150 min after the start of the insulin infusion. Insulin-mediated total body glucose disposal, glycolysis, glycogenesis and glucose oxidation were similar during the insulin clamp studies performed without and with misoprostol in both the diabetic and non-diabetic groups. These results demonstrate that the acute administration of misoprostol does not enhance insulin-mediated glucose disposal in either type-2-diabetic or non-diabetic subjects.

The identification and cloning of a murine major basic protein gene expressed in eosinophils.

The existence of a murine homologue of the major basic protein (MBP) found in human eosinophil granules was initially hypothesized from structural similarities at the electron microscopic level. The results presented in this study have extended these observations by describing the identification/purification of a mouse MBP (mMBP) and the cloning of the gene encoding this eosinophil granule protein. Using protein purification methodologies with extravascular eosinophils, an mMBP homologue has been identified on the basis of strong (64%) N-terminal sequence homology with the mature human MBP (hMBP). Since hMBP results from a proteolytic cleavage of a precursor molecule, this sequence conservation suggests that the mouse granule protein is processed by a similar mechanism. The gene encoding mMBP was isolated using a hMBP cDNA clone as a heterologous probe in low criteria screens of mouse genomic and cDNA libraries. The genomic structure and nucleotide sequence of the mMBP exons are well conserved with the human gene, although homology alignments of the encoded proteins show that extensive sequence conservation occurs only in the mature portion of the MBP molecules. Expression data demonstrate that this gene is transcriptionally active in tissues containing eosinophil progenitor cells, such as femoral bone marrow. Genomic Southern blots using the mMBP gene at reduced stringency reveal the potential existence of a second, more divergent MBP-like sequence in the mouse. This suggests that, as with guinea pigs, the mouse genome may also encode the eosinophil major basic protein from more than one gene.