A119 AN EX VIVO MODEL TO STUDY THE GUT SEROTONERGIC SYSTEM RESPONSE TO LIVE AND HEAT-KILLED LACTOBACILLUS RHAMNOSUS STRAIN JB-1

Background

Enterochromaffin (EC) cells are one of the most abundant enteroendocrine cells in the intestinal epithelium, responsible for producing and storing the largest pool of serotonin or 5-hydroxytryptamine (5-HT) in the body. 5-HT has been shown to be important for modulating a large number of gastrointestinal reflexes in health and disease. 5-HT can stimulate extrinsic (vagal and spinal afferents) or intrinsic primary afferent neurons (IPANs) which are involved in motility, secretion and vasodilation within the intestines. Where EC cell localized enzyme tryptophan hydroxylase (TpH) isoform 1 is responsible for 5-HT synthesis, serotonin reuptake transporter (Sert) and monoamine oxidase A (Mao A) are responsible for termination by uptake and metabolism of 5-HT respectively. Our previous research has demonstrated the effects Lactobacillus rhamnosus (JB-1) on the firing frequency of spinal nerve fibres and motility. Increasing interest is being focused on potential health benefits of heat-inactivated microbes and purified bacterial components. However, the effect of these heat-killed bacteria on the intestinal epithelium cells, particularly on EC cells, is unknown.

Aims

Small intestinal organoids are shown to recapitulate in vivo characteristics of the small intestine epithelium. The present study aims to assess the suitability of intestinal organoids to study bacterial effects on the serotonergic system in the gut. Here we determined changes in the gene expression of key mediators in the serotonergic system [serotonin reuptake transporter (Sert), tryptophan hydroxylase-1 (Tph-1) and monoamine oxidase A (Mao A)] in response to live and heat-killed JB-1.

Methods

Male C57bl/6 mice aged 6–8 weeks were used for both ex vivo and in vivo experiments. Jejunal organoids were grown from whole crypts isolated using DTT-EDTA solution. Live and heat-killed JB-1 bacteria were used as treatments. Gene expression analysis was performed on jejunal organoids and jejunum tissue using qRT-PCR.

Results

JB-1 induced a significant increase in gene expression of Sert, Mao A and Tph-1. No significant difference was observed between the effects of live and heat-killed bacteria. In contrast the JB-1 increased expression of the peptide hormone CCK. Effects of JB-1 on gene expression in organoid culture were reflective of changes observed in in vivo experiments involving feeding of the bacteria.

Conclusions

Ex vivo organoid culture could be a useful tool in studying mechanisms underlying bacterial effects on serotonergic signalling. The observation that heat-killed bacteria produced comparable effects to the live organism suggests the possibility of isolating active 5-HT modulating components from these strains. Future research will focus on identifying such bacterial components and how their effects on gene expression influence serotonin availability

Funding Agencies

None

Differences in cecal microbiome of selected high and low feather-pecking laying hens

In mammals, it has become increasingly clear that the gut microbiota influences not only gastrointestinal physiology but also modulates behavior. In domestic birds, ceca have the greatest gastrointestinal microbial population. Feather-pecking (FP) behavior in laying hens is one of the most important unsolved behavioral issues in modern agriculture. The aim of the present study was to assess the cecal microbial community of divergently selected high (HFP; n = 20) and low (LFP; n = 20) feather-pecking birds at 60 wk of age. The cecal samples were subjected to community profiling of 16S rRNA and in silico metagenomics using a modified bar-coded Illumina sequencing method on a MiSeq Illumina sequencer. Our results revealed that compared to HFP birds, LFP birds are characterized by an increased overall microbial diversity (beta diversity) shown by a difference in the Bray–Curtis index (R² = 0.171, P < 0.05). Furthermore, operational taxonomic unit comparisons showed an increased presence of Clostridiae and decreased presence of Lactobaccillacae in HFP birds when compared to LFP birds (False Discovery Rate < 0.05, Mann–Whitney comparisons). Our data indicate that there may be differences in the cecal profile between these 2 lines of laying hens. More research, building on this first study using sequencing technology for profiling the chicken cecal microbiome, will be needed in order to reveal if and how there exists a functional link between the performance of FP and the cecal microbial community.

Lactobacillus rhamnosus strain JB-1 reverses restraint stress-induced gut dysmotility

BACKGROUND

Environmental stress affects the gut with dysmotility being a common consequence. Although a variety of microbes or molecules may prevent the dysmotility, none reverse the dysmotility.

METHODS

We have used a 1 hour restraint stress mouse model to test for treatment effects of the neuroactive microbe, L. rhamnosus JB-1^™ . Motility of fluid-filled ex vivo gut segments in a perfusion organ bath was recorded by video and migrating motor complexes measured using spatiotemporal maps of diameter changes.

KEY RESULTS

Stress reduced jejunal and increased colonic propagating contractile cluster velocities and frequencies, while increasing contraction amplitudes for both. Luminal application of 10E8 cfu/mL JB-1 restored motor complex variables to unstressed levels within minutes of application. L. salivarius or Na.acetate had no treatment effects, while Na.butyrate partially reversed stress effects on colonic frequency and amplitude. Na.propionate reversed the stress effects for jejunum and colon except on jejunal amplitude.

CONCLUSIONS & INFERENCES

Our findings demonstrate, for the first time, a potential for certain beneficial microbes as treatment of stress-induced intestinal dysmotility and that the mechanism for restoration of function occurs within the intestine via a rapid drug-like action on the enteric nervous system.

Attenuation of food allergy symptoms following treatment with human milk oligosaccharides in a mouse model

BACKGROUND

The prebiotic nature of human milk oligosaccharides (HMOs) and increasing evidence of direct immunomodulatory effects of these sugars suggest that they may have some therapeutic potential in allergy. Here, we assess the effect of two HMOs, 2'-fucosyllactose and 6'-sialyllactose, on symptomatology and immune responses in an ovalbumin-sensitized mouse model of food allergy.

METHODS

The effects of oral treatment with 2'-fucosyllactose and 6'-sialyllactose on anaphylactic symptoms induced by oral ovalbumin (OVA) challenge in sensitized mice were investigated. Mast cell functions in response to oral HMO treatment were also measured in the passive cutaneous anaphylaxis model, and direct effects on IgE-mediated degranulation of mast cells were assessed.

RESULTS

Daily oral treatment with 2'-fucosyllactose or 6'-sialyllactose attenuated food allergy symptoms including diarrhea and hypothermia. Treatment with HMOs also suppressed antigen-induced increases in mouse mast cell protease-1 in serum and mast cell numbers in the intestine. These effects were associated with increases in the CD4(+) CD25(+) IL-10(+) cell populations in the Peyer's patches and mesenteric lymph nodes, while 6'-sialyllactose also induced increased IL-10 and decreased TNF production in antigen-stimulated splenocytes. Both 2'-fucosyllactose and 6'-sialyllactose reduced the passive cutaneous anaphylaxis response, but only 6'-sialyllactose directly inhibited mast cell degranulation in vitro, at high concentrations.

CONCLUSIONS

Our results suggest that 2'-fucosyllactose and 6'-sialyllactose reduce the symptoms of food allergy through induction of IL-10(+) T regulatory cells and indirect stabilization of mast cells. Thus, human milk oligosaccharides may have therapeutic potential in allergic disease.

Spatiotemporal maps reveal regional differences in the effects on gut motility for Lactobacillus reuteri and rhamnosus strains

BACKGROUND

Commensal bacteria such as probiotics that are neuroactive acutely affect the amplitudes of intestinal migrating motor complexes (MMCs). What is lacking for an improved understanding of these motility effects are region specific measurements of velocity and frequency. We have combined intraluminal pressure recordings with spatiotemporal diameter maps to analyze more completely effects of different strains of beneficial bacteria on motility.

METHODS

Intraluminal peak pressure (PPr) was measured and video recordings made of mouse ex vivo jejunum and colon segments before and after intraluminal applications of Lactobacillus rhamnosus (JB-1) or Lactobacillus reuteri (DSM 17938). Migrating motor complex frequency and velocity were calculated.

KEY RESULTS

JB-1 decreased jejunal frequencies by 56% and 34% in colon. Jejunal velocities increased 171%, but decreased 31% in colon. Jejunal PPr decreased by 55% and in colon by 21%. DSM 17938 increased jejunal frequencies 63% and in colon 75%; jejunal velocity decreased 57%, but increased in colon 146%; jejunal PPr was reduced 26% and 12% in colon. TRAM-34 decreased frequency by 71% and increased velocity 200% for jejunum, but increased frequency 46% and velocity 50% for colon; PPr was decreased 59% for jejunum and 39% for colon.

CONCLUSIONS & INFERENCES

The results show that probiotics and other beneficial bacteria have strain and region-specific actions on gut motility that can be successfully discriminated using spatiotemporal mapping of diameter changes. Effects are not necessarily the same in colon and jejunum. Further research is needed on the detailed effects of the strains on enteric neuron currents for each gut region.

Bacterial strain-specific induction of Foxp3+ T regulatory cells is protective in murine allergy models

BACKGROUND

The incidence of atopic disease has increased dramatically during recent decades and the potential immunoregulatory influence of the microbiota in these individuals is under investigation.

OBJECTIVE

The aim of our study was to identify a bacterial strain that is protective in murine allergy models and to determine if microbial induction of T regulatory cells was associated with protection from allergic inflammation.

METHODS

Three microbes (Bifidobacterium breve AH1205, B. longum AH1206 and Lactobacillus salivarius AH102) of human origin were fed to newborn, adult and germ-free animals. Induction of Foxp3(+) T regulatory cells was assessed by flow cytometry. Gene array analysis was performed on Peyer's patches. Strains were also examined for their protective effects in the ovalbumin (OVA) respiratory allergy model and the OVA-cholera toxin dietary allergy model.

RESULTS

Bifidobacterium longum AH1206 consumption resulted in increased numbers of Foxp3(+) T regulatory cells in infant, adult and germ-free animals. B. breve AH1205 induced Foxp3(+) T regulatory cell expansion only in infant mice while L. salivarius AH102 did not alter T regulatory cell numbers in any animal model tested. B. longum AH1206 reduced the Peyer's patch gene expression associated with antigen presentation, TLR signalling and cytokine production while increasing the expression of genes associated with retinoic acid metabolism. B. longum AH1206 protected against airway inflammation in OVA-sensitized animals and B. longum AH1206 blocked the induction of IgE to orally administered OVA. Neither B. breve AH1205 nor L. salivarius AH102 had a protective effect in either model.

CONCLUSION

Bacterial strain-specific induction of Foxp3(+) T regulatory cells in vivo is associated with protection from respiratory and oral allergy.

Autonomic nervous system regulates secretion of anti-inflammatory prohormone SMR1 from rat salivary glands

The autonomic nervous system regulates the secretion of bioactive proteins and peptides from salivary glands that can be important in systemic physiological responses. The prohormone submandibular rat-1, which is highly expressed in rat submandibular glands, can be cleaved to produce polypeptides with analgesic and anti-inflammatory activities. Human genes related to submandibular rat-1 have conserved biological functions and are potentially important in pain suppression, erectile function, and inflammation. In this study we describe the differential expression and posttranslational modification of submandibular rat-1 protein in salivary glands, the urogenital tract, lung, blood, and saliva in male Sprague-Dawley and Brown Norway rats. Submandibular rat-1 protein is secreted into saliva after the administration of beta-adrenergic or cholinergic agonists. Removal of the sympathetic ganglion that innervates the salivary glands results in increased levels of submandibular rat-1 protein in salivary glands. The secretion of submandibular rat-1 in response to physiological stress may provide a large pool of submandibular rat-1-derived peptide products that can promote analgesia and decrease inflammation locally and systemically. This pathway may be conserved among mammals and may constitute an important anti-inflammatory and analgesic response to stress.

Inhibitory effects of Lactobacillus reuteri on visceral pain induced by colorectal distension in Sprague-Dawley rats

BACKGROUND AND AIMS

Probiotic bacteria are being investigated as possible treatments for many intestinal disorders. The present study aimed to explore the effects of live, heat killed, or gamma irradiated Lactobacillus reuteri on cardio-autonomic response and single fibre unit discharge in dorsal root ganglia to colorectal distension in healthy Sprague-Dawley rats housed under conventional conditions. The effects of this treatment on somatic pain were also examined.

METHODS

1x10(9) bacteria were given by gavage for nine days. Colorectal distension occurred under anaesthesia. Heart rate was measured through continuous electrocardiography. Single fibre unit discharge was recorded from the 6th left lumbar dorsal root ganglion. Somatic pain was evaluated by the tail flick and paw pressure tests.

RESULTS

Colorectal distension caused a pressure dependent bradycardia in the control (native medium) group. Treatment with live, heat killed, or gamma irradiated bacteria as well as their products (conditioned medium) prevented the pain response even during the maximum distension pressure (80 mm Hg). Both viable and non-viable bacteria significantly decreased dorsal root ganglion single unit activity to distension. No effects on somatic pain were seen with any treatment.

CONCLUSIONS

Oral administration of either live or killed probiotic bacteria or conditioned medium inhibited the constitutive cardio-autonomic response to colorectal distension in rats through effects on enteric nerves. These data may provide a novel explanation for beneficial probiotic effects on visceral pain.

What is the physiological function of mast cells?

Under physiological conditions, skin mast cells preferentially localize around nerves, blood vessels and hair follicles. This observation, which dates back to Paul Ehrlich, intuitively suggests that these enigmatic, multifacetted protagonists of natural immunity are functionally relevant to many more aspects of tissue physiology than just to the generation of inflammatory and vasodilatory responses to IgE-dependent environmental antigens. And yet, for decades, mainstream-mast cell research has been dominated by a focus on the -undisputedly prominent and important - mast cell functions in type I immune responses and in the pathogenesis and management of allergic diseases. Certainly, it is hard to believe that the very large and rather selectively distributed number of mast cells in normal, uninflamed, non-infected, non-traumatized mammalian skin or mucosal tissue simply hanging around there lazily day and night, just wait for the odd allergen or parasite-associated antigen to come by so the mast cell can finally swing into action. Indeed, the past decade has witnessed a renaissance of mast cell research 'beyond allergy', along with a more systematic exploration of the surprisingly wide range of physiological functions that mast cells may be involved in. The current debate sketches many exciting horizons that have recently come into our vision during this intriguing, ongoing search.

Mast cells and nitric oxide: control of production, mechanisms of response

Mast cells are involved in numerous activities ranging from control of the vasculature, to tissue injury and repair, allergic inflammation and host defences. They synthesize and secrete a variety of mediators, activating and modulating the functions of nearby cells and initiating complex physiological changes. Interestingly, NO produced by mast cells and/or other cells in the microenvironment appears to regulate these diverse roles. This review outlines some of the pathways central to the production of NO by mast cells and identifies many of the tightly controlled regulatory mechanisms involved. Several cofactors and regulatory elements are involved in NO production, and these act at transcriptional and post-translational sites. Their involvement in NO production will be outlined and the possibility that these pathways are critically important in mast cell functions will be discussed. The effects of NO on mast cell functions such as adhesion, activation and mediator secretion will be examined with a focus on molecular mechanisms by which NO modifies intracellular signalling pathways dependent or independent of cGMP and soluble guanylate cyclase. The possibility that NO regulates mast cell function through effects on selected ion channels will be discussed. Metabolic products of NO including peroxynitrite and other reactive species may be the critical elements that affect the actions of NO on mast cell functions. Further understanding of the actions of NO on mast cell activities may uncover novel strategies to modulate inflammatory conditions.

Clinical consequences of mast cell heterogeneity

The heterogeneous morphological, biochemical and functional characteristics of mast cells from different species and from different tissue sites in the same species have been described for over 30 years. Far from being mere histochemical or pharmacological curiosities these differences have far reaching implications for therapeutic practice. This review concentrates on two important areas affected by mast cell heterogeneity, those of adverse reactions to therapeutic agents and the efficacy of anti-allergy therapy. In vitro studies of preformed and de novo synthesised mediator release have demonstrated a wide variability in the response of basophils and isolated mast cells to anti-allergy drugs and therapeutic agents such as radiographic contrast media, general anaesthetics, opioids and muscle relaxants. This heterogeneity is not limited to the mast cell's tissue of origin as there is also variability in the response of basophils and mast cells from different donors to the same drug or agent. These data have considerable clinical implications for the study of adverse drug reactions and the design of novel anti-allergic drugs.

Sensory neuropeptides induce histamine release from bronchoalveolar lavage cells in both nonasthmatic coughers and cough variant asthmatics

BACKGROUND

Sensory neuropeptides have been suggested to play a role in the pathogenesis of a number of respiratory diseases including asthma and chronic non-productive cough.

OBJECTIVES

To investigate the action of sensory neuropeptides on airway mast cells obtained by bronchoalveolar lavage (BAL).

METHODS

BAL was performed on 23 nonasthmatic patients with cough (NAC), 11 patients with cough variant asthma (CVA) and 10 nonatopic controls. Washed lavage cells were stimulated (20 min, 37 degrees C) with calcitonin gene-related peptide (CGRP), neurokinin A (NKA) and substance P (25 and 50 micromol/L).

RESULTS

The neuropeptides tested induced histamine release in all groups studied. Only CGRP (50 micromol/L) induced significantly more histamine release from both NAC and CVA patients compared with control subjects (P = 0.038 and 0.045, respectively).

CONCLUSION

Regardless of aetiology, mast cells from patients with chronic cough appear to have an increased responsiveness to CGRP compared with controls. The results of the present study suggest that the role of CGRP in chronic cough should be further investigated.

Adenosine, mast cells and asthma

The aim of this article is to review the interplay between adenosine and mast cells in asthma. Adenosine is an endogenous nucleoside released from metabolically active cells and generated extracellularly via the degradation of released ATP. It is a potent biological mediator that modulates the activity of numerous cell types including platelets, neutrophils and mast cells via action at specific adenosine receptors (A1, A2a, A2b, A3). These receptors are expressed on mast cells but the exact pattern of receptor subtype expression depends on the source of the mast cells. Adenosine is also a potent bronchoconstricting agent and is suggested to contribute to the pathophysiology of asthma. Evidence is provided to suggest that the nucleoside exerts its influence on the asthmatic condition through its ability to modulate the release of mast cell derived mediators. However, the mechanism of adenosine/mast cell interaction which contributes to asthma remains unclear. Progress in the area has been hampered by the heterogeneity of mast cell responses and a lack of highly specific receptor agonists and antagonists. The expression of different adenosine receptor subtypes on mast cells is described. The final section of the review presents data to suggest that BAL mast cells may provide an accurate and relevant model for future investigations and together with the development of superior pharmacological tools, may aid the realisation of the therapeutic potential of adenosine/mast cell interactions in asthma. In conclusion, the role of adenosine in asthma is clearly complex. A better understanding of the contribution of adenosine to the asthmatic condition may lead to novel therapeutic approaches in the treatment of the disease.

Adenosine induces histamine release from human bronchoalveolar lavage mast cells

Previous studies have shown that in vitro adenosine enhances histamine release from activated human lung mast cells obtained by enzymic dispersion of lung parenchyma. However, adenosine alone has no effect on histamine release from these cells. Given the evidence for direct activation of mast cells after endobronchial challenge with adenosine and previous studies indicating that mast cells obtained at bronchoalveolar lavage are a better model for asthma studies than those obtained by enzymic dispersion of lung tissue, the histamine-releasing effect of adenosine was examined on lavage mast cells. Bronchoalveolar lavage fluid was obtained from patients attending hospital for routine bronchoscopy (n=54). Lavage cells were challenged with adenosine or adenosine receptor agonists (20 min, 37 degrees C) and histamine release determined using an automated fluorometric assay. Endogenous adenosine levels were also measured in lavage fluid (n=9) via an HPLC method. Adenosine alone caused histamine release from lavage mast cells in 37 of 54 patients with a maximal histamine release of 20.56+/-2.52% (range 5.2-61%). The adenosine receptor agonists (R)-N6-(2-phenylisopropyl)adenosine, 5'-N-ethylcarboxamidoadenosine and CGS21680 also induced histamine release from lavage mast cells. Preincubation of lavage mast cells with the adenosine receptor antagonist xanthine amine congener caused significant inhibition of the response to adenosine (P=0.007). There was an inverse correlation between endogenous adenosine levels in the lavage fluid and the maximal response to in vitro adenosine challenge of the lavage cells. The findings of the present study indicate a means by which adenosine challenge of the airways can induce bronchoconstriction and support a role for adenosine in the pathophysiology of asthma. The results also suggest that cells obtained from bronchoalveolar lavage fluid may provide the ideal model for the testing of novel, adenosine receptor, targeted therapies for asthma.

Bronchoalveolar lavage findings in patients with chronic nonproductive cough

Mast cells and eosinophils may play a role in the pathophysiology of chronic cough in nonasthmatics. It is unknown, however, whether degranulation of these cells occurs in the airways of such patients. Thirty-five nonsmoking patients referred with a chronic nonproductive cough (mean cough duration 76.2 months) were evaluated using a comprehensive diagnostic protocol. Bronchoalveolar lavage (BAL) cell differentials and BAL histamine, tryptase and eosinophilic cationic protein (ECP) concentrations were determined. Ten nonsmoking healthy volunteers served as controls. Diagnostic subgroups were identified: eight postnasal drip syndrome (PNDS), seven cough variant asthma (CVA), seven gastro-esophageal reflux (GOR), seven dual aetiology and six idiopathic. Nonasthmatic coughers (NAC) were characterized as those patients without bronchial hyperresponsiveness on histamine challenge and whose cough had either responded to therapy for PNDS or GOR or failed to improve with antiasthma therapy. There was a significant increase in both eosinophil and mast cell numbers (p<0.05) and in histamine levels (p = 0.027) when NAC patients were compared with controls. Tryptase and ECP levels were elevated in 7 of 23 and 6 of 23 NAC patients, respectively. In conclusion, airway inflammatory cell numbers are not only increased but also activated, suggesting an important role for airways inflammation in the pathophysiology of chronic nonproductive cough.

New practices in the transitional care center improve outcomes for babies and their families

Assuming sole responsibility of parenting a high-risk infant after a prolonged hospital stay can be a complex and traumatic event, especially when the infant is discharged with residual health care problems requiring medical management and treatment at home. A parent's ability to successfully transition the management of their infant's care from hospital to home depends on a collaborative discharge process where parents are ongoing, full participants. The Transitional Care Center environment makes learning comfortable for parents, allows parental care-giver mastery to occur, and fosters family integration. Favorable clinical outcomes concurrent with decreased lengths of hospital stays and readmission rates have been demonstrated.

Analysis of the RPGR gene in 11 pedigrees with the retinitis pigmentosa type 3 genotype: paucity of mutations in the coding region but splice defects in two families

X-linked retinitis pigmentosa (XLRP) is a severe form of inherited progressive retinal degeneration. The RP3 (retinitis pigmentosa type 3) locus at Xp21.1 is believed to account for the disease in the majority of XLRP families. Linkage analysis and identification of patients with chromosomal deletion have refined the location of the RP3 locus and recently have led to the cloning of the RPGR (retinitis pigmentosa GTPase regulator) gene, which has been shown to be mutated in 10%-15% of XLRP patients. In order to systematically characterize the RPGR mutations, we identified 11 retinitis pigmentosa type III (RP3) families by haplotype analysis. Sequence analysis of the PCR-amplified genomic DNA from patients representing these RP3 families did not reveal any causative mutation in RPGR exons 2-19, spanning >98% of the coding region. In patients from two families, we identified transition mutations in the intron region near splice sites (IVS10+3 and IVS13-8). RNA analysis showed that both splice-site mutations resulted in the generation of aberrant RPGR transcripts. Our results support the hypothesis that mutations in the reported RPGR gene are not a common defect in the RP3 subtype of XLRP and that a majority of causative mutations may reside either in as yet unidentified RPGR exons or in another nearby gene at Xp21.1.

A recombination outside the BB deletion refines the location of the X linked retinitis pigmentosa locus RP3

Genetic loci for X-linked retinitis pigmentosa (XLRP) have been mapped between Xp11.22 and Xp22.13 (RP2, RP3, RP6, and RP15). The RP3 gene, which is responsible for the predominant form of XLRP in most Caucasian populations, has been localized to Xp21.1 by linkage analysis and the map positions of chromosomal deletions associated with the disease. Previous linkage studies have suggested that RP3 is flanked by the markers DXS1110 (distal) and OTC (proximal). Patient BB was thought to have RP because of a lesion at the RP3 locus, in addition to chronic granulomatous disease, Duchenne muscular dystrophy (DMD), mild mental retardation, and the McLeod phenotype. This patient carried a deletion extending approximately 3 Mb from DMD in Xp21.3 to Xp21.1, with the proximal breakpoint located approximately 40 kb centromeric to DXS1110. The RP3 gene, therefore, is believed to reside between DXS1110 and the proximal breakpoint of the BB deletion. In order to refine the location of RP3 and to ascertain patients with RP3, we have been analyzing several XLRP families for linkage to Xp markers. Linkage analysis in an American family of 27 individuals demonstrates segregation of XLRP with markers in Xp21.1, consistent with the RP3 subtype. One affected mate shows a recombination event proximal to DXS1110. Additional markers within the DXS1110-OTC interval show that the crossover is between two novel polymorphic markers, DXS8349 and M6, both of which are present in BB DNA and lie centromeric to the proximal breakpoint. This recombination places the XLRP mutation in this family outside the BB deletion and redefines the location of RP3.

Increased MCP-1, RANTES, and MIP-1alpha in bronchoalveolar lavage fluid of allergic asthmatic patients

Chemokines are cytokines that induce chemotaxis of inflammatory cells. We studied the presence of chemokines in bronchoalveolar lavage fluid (BALF) obtained from nine allergic asthmatic patients and six nonsmoking normal individuals. The cells were pelleted, and ribonucleic acid (RNA) was extracted by using RNAzol B. BALF was assayed for monocyte chemoattractant protein-1 (MCP-1), regulated upon activation in normal T cells, expressed, probably secreted (RANTES), macrophage inflammatory protein-1alpha (MIP-1alpha) and interleukin-8 (IL-8) by enzyme-linked immunosorbent assay (ELISA). The levels of MCP-1, RANTES, and MIP-1alpha were significantly higher in the asthma patients than in the control subjects (p<0.04). The concentrations of RANTES and MCP-1 correlated with the lymphocyte count in the BAL specimens (r = 0.61 and 0.68, respectively). BALF showed eosinophil chemotactic activity in vitro that was blocked by anti-RANTES and anti-MCP-3 antibodies. The total cellular RNA was reverse-transcribed and the complementary deoxyribonucleic acid (cDNA) was amplified with the polymerase chain reaction (PCR) for MCP-1, MCP-3, RANTES, MIP-1alpha, IL-8, and beta-actin. We found that messenger ribonucleic acids (mRNAs) for MCP-1, MCP-3, RANTES, MIP-1alpha, and IL-8 were produced by BAL cells from most asthmatic and normal subjects. We conclude that chemokines are produced in the airways, and that an increased recovery of MCP-1, RANTES, and MIP-1alpha is observed in allergic asthmatic patients.

Paclitaxel as second and subsequent therapy for metastatic breast cancer: activity independent of prior anthracycline response

PURPOSE

Two phase II clinical trials were performed to determine efficacy and tolerability of paclitaxel (Taxol; Bristol-Myers Squibb Co, Wallingford, CT) and granulocyte colony-stimulating factor ([G-CSF] Neupogen; Amgen, Inc, Thousand Oaks, CA) as second or subsequent therapy for metastatic breast cancer.

PATIENTS AND METHODS

Paclitaxel plus G-CSF was administered as a second stage IV regimen to 25 patients with metastatic breast cancer at a dose of 250 mg/m2 intravenously over 24 hours. Fifty-two patients received paclitoxel plus G-CSF at 200 mg/m2 as a third or subsequent regimen (no restriction on number of prior regimens or on prior high-dose chemotherapy). All patients had received prior anthracycline treatment, and ultimately had progressive bidimensionally measurable disease.

RESULTS

Twenty-five of 76 patients (32.8%) had a major objective response (95% confidence interval [CI], 14% to 37%). The median duration of response was 7 months (range, 1 to 20+). Responses were as likely in patients with disease demonstrated to be unresponsive to anthracycline, ie, de novo resistance (11 of 37, or 30%) as in those with disease that once exhibited anthracycline sensitivity, ie, acquired resistance, (10 of 31, or 32%). G-CSF administration was associated with febrile neutropenic episodes in 36 of 402 cycles (9%) in 16 of 76 patients (21%).

CONCLUSION

Paclitaxel's clinically significant activity against metastatic breast cancer extends to patients with many prior chemotherapy regimens. The lack of impact of prior doxorubicin therapy on the likelihood of subsequent response to paclitaxel suggests an important role for this agent in the treatment of refractory metastatic breast cancer.

The intracellular signal transduction mechanism of interleukin 5 in eosinophils: the involvement of lyn tyrosine kinase and the Ras-Raf-1-MEK-microtubule-associated protein kinase pathway

Interleukin 5 (IL-5) regulates the growth and function of eosinophils. The objective of this study was to investigate the intracellular signal transduction mechanism of IL-5 in eosinophils. Purified eosinophils were stimulated with IL-5, and the involvement of various kinases was investigated by immunoblotting, immune complex kinase assay, and in situ denatured/renatured kinase assay. We found that IL-5 induced tyrosine phosphorylation and activation of a number of kinases. Two species of lyn kinases (53 and 56 kD) were present in eosinophils. Both forms were Tyr-phosphorylated and activated rapidly within 1 min. Further, lyn kinase was physically associated with the IL-5 beta receptor in eosinophils. Ras was studied by immunoprecipitation followed by thin-layer chromatography. Ras bound higher quantities of [alpha-32P]guanosine 5'triphosphate upon stimulation with IL-5. Raf-1 kinase showed increased Tyr phosphorylation on immunoblotting and increased activity in the immune complex kinase assay. Two species of MEK (MAP or Erk kinase) (41 and 45 kD) were identified in eosinophils, which underwent autophosphorylation upon stimulation. Microtubule-associated protein (MAP) kinase (p44) was Tyr-phosphorylated on immunoblotting and had increased activity in the immune-complex kinase assay. MAP kinases were also studied after metabolic radiolabeling of the cells with [32P]orthophosphates. IL-5 stimulated phosphorylation of MAP kinases in situ. Thus, we have delineated major components of an important signaling pathway in eosinophils. We believe that one of the signals generated by IL-5 receptor activation is propagated through the lyn-Ras-Raf-1-MEK-MAP kinase pathway.

The interleukin-5/receptor interaction activates Lyn and Jak2 tyrosine kinases and propagates signals via the Ras-Raf-1-MAP kinase and the Jak-STAT pathways in eosinophils

We have shown that the interaction of interleukin (IL)-5 with the receptor activates Lyn tyrosine kinase within 1 min and Jak2 tyrosine kinase within 1-3 min. IL-5 also stimulates GTP binding to p21ras. The signal is subsequently propagated through the activation of Raf-1, MEK, and MAP kinases as shown by their increased autophosphorylation in vitro and phosphorylation in situ. Jak2 kinase has been shown to phosphorylate STAT nuclear proteins. The activation of STAT nuclear factors was studied by electrophoretic mobility shift assay using a gamma activation site (GAS) probe. We found that IL-5 induces two GAS-binding proteins in eosinophils, one of which is STAT1. We conclude that IL-5 induced signals are propagated through two distinct pathways: (1) Lyn-->Ras-->Raf-1-->MEK-->MAP kinase and (2) Jak2-->STAT1.

Monocyte chemotactic protein-2, monocyte chemotactic protein-3, and fibroblast-induced cytokine. Three new chemokines induce chemotaxis and activation of basophils

Cytokine-dependent mediator release from basophils and mast cells may play an important role in the pathogenesis of allergic and inflammatory conditions. Many C-C chemokines have been found to activate basophils and mast cells. We investigated the effect of three newly identified C-C chemokines, monocyte chemotactic protein-2 and -3 (MCP-2, MCP-3) and fibroblast-induced cytokine (FIC) on basophils and mast cells. We found that all three cytokines induced histamine secretion from basophils in a dose-dependent manner. The secretion of histamine was a Ca(2+)-dependent process. MCP-3 was the most potent activator of basophils. MCP-3 and FIC activated basophils from all study subjects, whereas the histamine release by MCP-2 was donor-dependent. The histamine-releasing activity of MCP-2, MCP-3, and FIC was compared with that of MCP-1, RANTES, and macrophage inflammatory protein-1 alpha using basophils from 10 donors. MCP-1 was the most potent among all the C-C chemokines. However, MCP-3 was nearly as potent. MCP-2, MCP-3, and FIC induced significant chemotaxis of basophils. None of the cytokines activated mouse peritoneal mast cells. The synthesis of mRNA for MCP-3 was investigated by reverse-transcription PCR using allergen-stimulated PBMC and bronchoalveolar lavage cells. Both MNC and bronchoalveolar lavage cells expressed mRNA for MCP-3. The results of this study indicate that MCP-2, MCP-3, and FIC are novel histamine-releasing factors.

Monocyte chemotactic protein-2, monocyte chemotactic protein-3, and fibroblast-induced cytokine. Three new chemokines induce chemotaxis and activation of basophils

Cytokine-dependent mediator release from basophils and mast cells may play an important role in the pathogenesis of allergic and inflammatory conditions. Many C-C chemokines have been found to activate basophils and mast cells. We investigated the effect of three newly identified C-C chemokines, monocyte chemotactic protein-2 and -3 (MCP-2, MCP-3) and fibroblast-induced cytokine (FIC) on basophils and mast cells. We found that all three cytokines induced histamine secretion from basophils in a dose-dependent manner. The secretion of histamine was a Ca(2+)-dependent process. MCP-3 was the most potent activator of basophils. MCP-3 and FIC activated basophils from all study subjects, whereas the histamine release by MCP-2 was donor-dependent. The histamine-releasing activity of MCP-2, MCP-3, and FIC was compared with that of MCP-1, RANTES, and macrophage inflammatory protein-1 alpha using basophils from 10 donors. MCP-1 was the most potent among all the C-C chemokines. However, MCP-3 was nearly as potent. MCP-2, MCP-3, and FIC induced significant chemotaxis of basophils. None of the cytokines activated mouse peritoneal mast cells. The synthesis of mRNA for MCP-3 was investigated by reverse-transcription PCR using allergen-stimulated PBMC and bronchoalveolar lavage cells. Both MNC and bronchoalveolar lavage cells expressed mRNA for MCP-3. The results of this study indicate that MCP-2, MCP-3, and FIC are novel histamine-releasing factors.

Research utilization and the consumers of care: the parent's perspective

Parents and professionals enter into research relationships with differing expectations and purposes. Fifty parents were approached to request permission for their infant to participate in the Transition of the Preterm Infant to an Open Crib research utilization project. All parents agreed. Most parents were enthusiastic about the project and viewed the possible outcome of participation as enhancing the care and recovery of their infant. Some parents delayed granting permission until convinced of the successful results by observing other infants in the project. Some parents granted permission based on trust and faith in the care-giving system.

Transforming growth factor beta abrogates the effects of hematopoietins on eosinophils and induces their apoptosis

Hematopoietins, interleukin (IL)-3, IL-5, and granulocyte/macrophage colony-stimulating factor (GM-CSF) have previously been shown to prolong eosinophil survival and abrogate apoptosis. The objective of this study was to investigate the effect of transforming growth factor beta (TGF-beta) on eosinophil survival and apoptosis. Eosinophils from peripheral blood of mildly eosinophilic donors were isolated to > 97% purity using discontinuous Percoll density gradient. Eosinophils were cultured with hematopoietins with or without TGF-beta for 4 d and their viability was assessed. We confirmed previous observations that hematopoietins prolonged eosinophil survival and inhibited apoptosis. TGF-beta at concentrations > or = 10(-12) M abrogated the survival-prolonging effects of hematopoietins in a dose-dependent manner and induced apoptosis as determined by DNA fragmentation in agarose gels. The effect of TGF-beta was blocked by an anti-TGF-beta antibody. The anti-TGF-beta antibody also prolonged eosinophil survival on its own. The culture of eosinophils with IL-3 and GM-CSF stimulated the synthesis of GM-CSF and IL-5, respectively, suggesting an autocrine mechanism of growth factor production. TGF-beta inhibited the synthesis of GM-CSF and IL-5 by eosinophils. TGF-beta did not have any effect on the expression of GM-CSF receptors on eosinophils. We also studied the effect of TGF-beta on eosinophil function and found that TGF-beta inhibited the release of eosinophil peroxidase. Thus, TGF-beta seems to inhibit eosinophil survival and function. The inhibition of endogenous synthesis of hematopoietins may be one mechanism by which TGF-beta blocks eosinophil survival and induces apoptosis.

RANTES is a chemotactic and activating factor for human eosinophils

RANTES is a member of the 8-kDa cytokine family that has been shown to possess chemotactic activity for monocytes and CD4 T cells. In this study, we investigated whether RANTES could affect eosinophil chemotaxis and function. Peripheral blood eosinophils from blood donors were isolated on Percoll gradients to &gt; 98% purity and then used for chemotaxis, flow cytometry, eosinophil cationic protein release assay, and survival assay. We found that RANTES is chemotactic for eosinophils at 10(-9) to 10(-8) M concentrations. RANTES elicited 65% of the chemotactic response to 10(-7) M platelet-activating factor in all experiments. The mechanism of chemotaxis was investigated by studying the expression of adhesion molecules on eosinophils by flow cytometry. We found that RANTES up-regulated the expression of CD11b/CD18 on eosinophils in a dose-dependent manner. In another set of experiments, purified eosinophils incubated with various concentrations of RANTES released eosinophil cationic protein as measured by a RIA. We also investigated the effect of RANTES on eosinophil density. Leukocytes were incubated in the presence or absence of RANTES, and the distribution of eosinophils on discontinuous Percoll gradients was then examined. We found that eosinophils became hypodense (&lt; 1.085) when incubated in RANTES. However, unlike IL-3, RANTES did not affect the survival of eosinophils in a 4-day culture system. Thus, we established that RANTES is a chemotactic and activating factor for eosinophils.

RANTES is a chemotactic and activating factor for human eosinophils

RANTES is a member of the 8-kDa cytokine family that has been shown to possess chemotactic activity for monocytes and CD4 T cells. In this study, we investigated whether RANTES could affect eosinophil chemotaxis and function. Peripheral blood eosinophils from blood donors were isolated on Percoll gradients to > 98% purity and then used for chemotaxis, flow cytometry, eosinophil cationic protein release assay, and survival assay. We found that RANTES is chemotactic for eosinophils at 10(-9) to 10(-8) M concentrations. RANTES elicited 65% of the chemotactic response to 10(-7) M platelet-activating factor in all experiments. The mechanism of chemotaxis was investigated by studying the expression of adhesion molecules on eosinophils by flow cytometry. We found that RANTES up-regulated the expression of CD11b/CD18 on eosinophils in a dose-dependent manner. In another set of experiments, purified eosinophils incubated with various concentrations of RANTES released eosinophil cationic protein as measured by a RIA. We also investigated the effect of RANTES on eosinophil density. Leukocytes were incubated in the presence or absence of RANTES, and the distribution of eosinophils on discontinuous Percoll gradients was then examined. We found that eosinophils became hypodense (< 1.085) when incubated in RANTES. However, unlike IL-3, RANTES did not affect the survival of eosinophils in a 4-day culture system. Thus, we established that RANTES is a chemotactic and activating factor for eosinophils.