Genomic description of acquired fluconazole- and echinocandin-resistance in patients with serial Candida glabrata isolates

Candida glabrata is one of the most common causes of systemic candidiasis, often resistant to antifungal medications. To describe the genomic context of emerging resistance, we conducted a retrospective analysis of 82 serially collected isolates from 33 patients from population-based candidemia surveillance in the United States. We used whole-genome sequencing to determine the genetic relationships between isolates obtained from the same patient. Phylogenetic analysis demonstrated that isolates from 29 patients were clustered by patient. The median SNPs between isolates from the same patient was 30 (range: 7-96 SNPs), while unrelated strains infected four patients. Twenty-one isolates were resistant to echinocandins, and 24 were resistant to fluconazole. All echinocandin-resistant isolates carried a mutation either in the FKS1 or FKS2 HS1 region. Of the 24 fluconazole-resistant isolates, 17 (71%) had non-synonymous polymorphisms in the PDR1 gene, which were absent in susceptible isolates. In 11 patients, a genetically related resistant isolate was collected after recovering susceptible isolates, indicating in vivo acquisition of resistance. These findings allowed us to estimate the intra-host diversity of C. glabrata and propose an upper boundary of 96 SNPs for defining genetically related isolates, which can be used to assess donor-to-host transmission, nosocomial transmission, or acquired resistance. IMPORTANCE In our study, mutations associated to azole resistance and echinocandin resistance were detected in Candida glabrata isolates using a whole-genome sequence. C. glabrata is the second most common cause of candidemia in the United States, which rapidly acquires resistance to antifungals, in vitro and in vivo.

Presentation, clinical course and complications in trauma patients with concomitant COVID-19 infection

BACKGROUND

This study investigated the impact of COVID-19 infection on hospitalized trauma patients.

METHODS

A retrospective review of hospitalized trauma patients at a level I trauma center was performed from March-December 2020. Data pertaining to patient demographics, presentation and hospital course was compared between COVID positive and negative trauma patients.

RESULTS

There were 4,912 patients and 179 (3.64%) were COVID-19 positive. Demographics and clinical presentation did not differ significantly between those with and without concomitant COVID-19. However, COVID positive trauma patients had higher rates of acute kidney injury (p = 0.016), sepsis (p = 0.016), unplanned intubation (p = 0.002) and unplanned return to the ICU (p = 0.01). The COVID positive cohort also had longer hospital stays (p < 0.01) with no significant difference in mortality.

CONCLUSIONS

In the setting of an ongoing pandemic, awareness of the complications COVID positive trauma patients are predisposed to is important for providers.

60 Front Door Specialist Frailty MDT Working at MFT NHS Trust—The Therapy Team Poster Presentation

Introduction

The therapy team consists of physiotherapists, Occupational therapists and therapy technicians working generically to deliver a comprehensive therapy assessment to patients presenting in our Emergency Department, Clinical Decisions Unit and Medical Admissions Unit between the hours of 08:00–18:00 7 days a week. The therapists provide the hospitals frailty service in ED and MAU with early therapy assessment and intervention, supporting the provision of a Comprehensive Geriatric Assessment. The aims of our service are to provide early therapy assessment of our most vulnerable patients to avoid unnecessary hospital admissions and reduce readmission rates, and for those requiring hospital care to provide early mobilisation and discharge planning to reduce length of stay and complications associated with hospital admission. We provide the therapy component of the CGA as part of the specialist frailty MDT service and act as an interface with local community health and social services.

Method

A full review of our frailty MDT service was undertaken and a re-allocation of our resources and staff was piloted in July 2019.

During this pilot our therapy staff presence was re-distributed allowing greater patient numbers to be assessed promptly on their arrival to ED.

This adjustment supported the Frailty MDT actions of:

Results

Data collection showed total referrals to therapy increased from 67 (June 2019) to 160 (July 2019). In July same day discharges were at 43%; discharges ≥72 hours 24%; 7 day readmission at 9%; 28 day readmissions at 11% and 38% were referred to community services.

Conclusion

These changes enabled us to provide a full MDT frailty service to frail older people presenting at our ED in a timely manner and to a larger number of suitable patients.

Inactivation of Bacillus anthracis and Bacillus atrophaeus spores on different surfaces with ultraviolet light produced with a low-pressure mercury vapor lamp or light emitting diodes

AIMS

To obtain quantitative efficacy data of two ultraviolet light (UVC) technologies for surface inactivation of Bacillus anthracis Ames and Bacillus atrophaeus spores.

METHODS AND RESULTS

Spores were deposited onto test coupons and controls of four different materials, via liquid suspension or aerosol deposition. The test coupons were then exposed to UVC light from either a low-pressure mercury vapor lamp or a system comprised of light emitting diodes, with a range of dosages. Positive controls were held at ambient conditions and not exposed to UVC light. Following exposure to UVC, spores were recovered from the coupons and efficacy was quantified in terms of log₁₀ reduction (LR) in the number of viable spores compared to that from positive controls.

CONCLUSIONS

Decontamination efficacy varied by material and UVC dosage (efficacy up to 5·7 LR was demonstrated). There was no statistical difference in efficacy between the two species or between inoculation methods. Efficacy improved for the LED lamp at lower relative humidity, but this effect was not observed with the mercury vapor lamp.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study will be useful in determining whether UVC could be used for the inactivation of B. anthracis spores on different surface types.

Prevalence and predictors of anxiety in an African sample of recent stroke survivors

OBJECTIVES

Studies considering emotional disturbances in the setting of stroke have primarily focused on depression and been conducted in high-income countries. Anxiety in stroke survivors, which may be associated with its own unique sets of risk factors and clinical parameters, has been rarely investigated in sub-Saharan Africa (SSA). We assess the characteristics of anxiety and anxiety-depression comorbidity in a SSA sample of recent stroke survivors.

MATERIALS AND METHODS

We assessed baseline data being collected as part of an intervention to improve one-year blood pressure control among recent (≤1 month) stroke survivors in SSA. Anxiety in this patient population was measured using the Hospital Anxiety and Depression Scale (HADS), while the community screening instrument for dementia was used to evaluate cognitive functioning. Independent associations were assessed using logistic regression analysis.

RESULTS

Among 391 participants, clinically significant anxiety (HADS anxiety score≥11) was found in 77 (19.7%). Anxiety was comorbid with depression in 55 (14.1%). Female stroke survivors were more likely than males to have anxiety (OR=2.4, 95% CI=1.5-4.0). Anxiety was significantly associated with the presence of cognitive impairment after adjusting for age, gender and education (OR=6.8, 95% CI=2.6-18.0).

CONCLUSIONS

One in five recent stroke survivors in SSA has clinically significant anxiety, and well over 70% of those with anxiety also have depression. Future studies will need to determine what specific impact post-stroke anxiety may have on post-stroke clinical processes and outcomes.

Dietary fatty acids and arthritis

Musculoskeletal complaints are the second most frequent reason for medical treatments. Within these diseases rheumatoid arthritis (RA) and, especially, osteoarthritis (OA) are common. Although the causes of arthritis are multifactorial and not fully understood, clinical trials have generally shown benefit from dietary n-3 polyunsaturated fatty acids. This has usually been attributed to their anti-inflammatory properties. Recently we have used in vitro model systems to study the molecular mechanism(s) by which n-3 PUFAs may act to alleviate the symptoms of arthritis. These experiments showed that n-3 PUFAs reduce expression of cartilage-degrading proteinases, cyclooxygenase-2 and inflammatory cytokines. Eicosapentaenoic acid (EPA) was more effective than docosahexaenoic acid (DHA) or alpha-linolenic acid. The data provide a scientific rationale for the consumption of n-3 fatty acids as part of a healthy diet and perhaps in treating arthritis.

Relative efficacies of omega-3 polyunsaturated fatty acids in reducing expression of key proteins in a model system for studying osteoarthritis

OBJECTIVE

To assess the relative efficacy of three different omega-3 (n-3) polyunsaturated fatty acids (PUFAs) in suppressing the mRNA levels for important proteins involved in the etiology of osteoarthritis (OA).

METHODS

A model cell culture system (bovine chondrocytes) was used. Inflammatory factors and enzymes involved in OA were induced by exposure of the chondrocyte cultures to interleukin-1alpha (IL-1alpha). The effect of pre-incubating cultures with various amounts of exogenous fatty acids on subsequent levels of mRNAs was assessed by reverse transcription-polymerase chain reactions (RT-PCR).

RESULTS

Exposure of cultures to IL-1alpha induced expression of the cartilage proteinases A Disintegrin And Metalloproteinase with ThromboSpondin motifs (ADAMTS)-4 and ADAMTS-5, cyclooxygenase (COX)-2, the matrix metalloproteinase (MMP)-3 and the inflammatory cytokines IL-1alpha, interleukin-1beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha). n-3 PUFAs were able to reduce the levels of mRNA for ADAMTS-4, ADAMTS-5, MMP-3, MMP-13, COX-2 (but not COX-1), IL-1alpha, IL-1beta and TNF-alpha. Eicosapentaenoic acid (EPA) was the most effective, followed by docosahexaenoic (DHA) and then alpha-linolenic (ALA) acid. The n-6 PUFA, arachidonic acid (AA) had no effect.

CONCLUSION

These results show that omega-3 (n-3) PUFAs cause a reduction in the mRNA levels for various proteins known to be important in the pathology of OA. They provide a molecular explanation, at least in part, for beneficial effects of dietary omega-3 PUFAs for the amelioration of symptoms of the disease. The relative efficacy of EPA suggests that this omega-3 PUFA may be especially useful for dietary supplementation in patients with OA.

Functionalisation of glass with iron oxide nanoparticles produced by laser pyrolysis

In the present work, a new process for depositing nanoparticle layers onto glass has been developed by using one of the most interesting nanoparticle generation technologies at the moment, which is based on the pyrolysis induced by laser of vapours combined with CVD of the particles onto glass. Nanoparticles prepared by this method were deposited into a hot silica substrate obtaining new nanocomposites with unique properties. The coated glasses present new specific functionalities such as colour, and interesting magnetic and optical properties. Control of the thickness and the iron oxide phase, either magnetic or not, has been achieved by adjusting the experimental conditions. Thus, thickness is controlled by the glass and the precursor temperature, while the iron phase is controlled by the precursor temperature and the nature and the flow of the carrier gas. This process is inexpensive, adaptable to current glass production technologies and takes place at atmospheric pressure.

Cytokine networking in lungs of immunocompetent mice in response to inhaled Aspergillus fumigatus

Cytokine networking in the lung in response to inhaled Aspergillus fumigatus was assessed using a murine model of primary pulmonary aspergillosis in immunocompetent Crl:CF-1 mice. Inhalation of virulent A. fumigatus (6 x 10(6) CFU) resulted in the induction of interleukin 18 (IL-18), tumor necrosis factor alpha (TNF-alpha), IL-12, and gamma interferon (IFN-gamma) protein in bronchoalveolar lavage fluid and/or lung tissue. Induction of immunoreactive IL-18 preceded induction of TNF-alpha protein, which preceded induction of immunoreactive IL-12 and IFN-gamma. Real-time reverse transcriptase (RT) PCR analysis of infected lung tissue demonstrated that induction of IL-18 protein also preceded induction of pulmonary TNF-alpha, IL-12, and IFN-gamma mRNAs. Mice were subsequently treated with cytokine-specific neutralizing monoclonal antibodies (MAbs) to the IL-18 receptor (anti-IL-18R MAb), TNF-alpha (anti-TNF-alpha MAb), IL-12 (anti-IL-12 MAb), and/or IFN-gamma (anti-IFN-gamma MAb), and effects on intrapulmonary cytokine activity and growth of A. fumigatus were assessed in infected lung homogenates. Simultaneous neutralization of IL-12 and IL-18 resulted in decreased levels of immunoreactive TNF-alpha, while neutralization of IL-18, TNF-alpha, or IL-12 alone or of IL-18 and IL-12 together resulted in decreased levels of immunoreactive IFN-gamma. Simultaneous neutralization of IL-12 and IL-18 or neutralization of TNF-alpha alone or in combination with IL-12, IL-18, or IFN-gamma also resulted in a significant increase in A. fumigatus CFU in lung tissue. Taken together, these results demonstrate that endogenous IL-18, IL-12, and TNF-alpha, through their modulatory effects on both intrapulmonary cytokine activity and growth of A. fumigatus, play key roles in host defense against primary pulmonary aspergillosis.

Immunomodulatory role of endogenous interleukin-18 in gamma interferon-mediated resolution of replicative Legionella pneumophila lung infection

The in vivo role of endogenous interleukin-18 (IL-18) in modulating gamma interferon (IFN-gamma)-mediated resolution of replicative Legionella pneumophila lung infection was assessed using a murine model of Legionnaires' disease. Intratracheal inoculation of A/J mice with virulent bacteria (10(6) L. pneumophila organisms per mouse) resulted in induction of IL-18 protein in bronchoalveolar lavage fluid (BALF) and intrapulmonary expression of IL-18 mRNA. Real-time quantitative RT-PCR analysis of infected lung tissue demonstrated that induction of IL-18 in BALF preceded induction of IL-12 and IFN-gamma mRNAs in the lung. Blocking intrapulmonary IL-18 activity by administration of a monoclonal antibody (MAb) to the IL-18 receptor (anti-IL-18R MAb) prior to L. pneumophila infection inhibited induction of intrapulmonary IFN-gamma production but did not significantly alter resolution of replicative L. pneumophila lung infection. In contrast, blocking endogenous IL-12 activity by administration of anti-IL-12 MAb) alone or in combination with anti-IL-18R MAb inhibited induction of intrapulmonary IFN-gamma and resulted in enhanced intrapulmonary growth of the bacteria within 5 days postinfection. Taken together, these results demonstrate that IL-18 plays a key role in modulating induction of IFN-gamma in the lung in response to L. pneumophila and that together with IL-12, IL-18 regulates intrapulmonary growth of the bacteria.

Aggravation of licensing procedures by doubtful thermodynamic data

Environmental prognosis by geochemical modelling is a scientific approach to several open questions of general public interest. Two prominent fields where geochemical modelling holds an important share are the remediation of contaminated former uranium mining areas and safety assessment of radioactive waste repositories in the geosphere. In both fields, application of geochemical modelling is stipulated by public authorities. The enormous complexity of models that can be handled by computers rises the awareness on the meaningfulness of a modelling result and demands for provision of an estimate of the dependability of a calculation output by the computers. It is obvious that bias, over- and underestimation of uncertainty in input data reduces the relevance of the calculation output. Chemistry contributes important data to geochemical modelling, both from field analysis and in the fundamental physico-chemical quantities enclosed into the thermodynamic data base. Some examples will be given where progress in quality assessment of chemical data may further the predictive power of geochemical modelling.

Modeling therapeutic strategies in rheumatoid arthritis: use of decision analysis and Markov models

OBJECTIVE

The management of patients with rheumatoid arthritis (RA) is controversial, with a number of different proposed treatment strategies based on different conceptions of the natural history of the disease and different interpretations of the efficacy and effectiveness of the drugs used for treatment. We attempted to develop a theoretical framework to assess the effectiveness of different treatment regimens for RA.

METHODS

We used decision analysis to structure the problem of comparing sequential monotherapy to a combination strategy. Subsequently, we used 3 different estimates of drug effectiveness: one from expert rheumatologists; a metaanalysis; and a recent nationwide survey of American rheumatologists, in a Markov model. Last, we utilized published duration of therapy data to model drug treatment over time.

RESULTS

Estimates of drug effectiveness differed substantially among rheumatologists, but regardless of the estimates and the treatment strategy used, the model predicted over 90% of patients improved by the 3rd drug trial. Over time, treatment patterns in our model resemble the "sawtooth" pattern previously observed.

CONCLUSION

Treatment strategies in RA are difficult to model because of uncertainty in both the structure of the model and the data needed to perform the analysis. These models tend to overestimate the effectiveness of drug sequences because of nonindependence between therapies, probably due to sequence effects, a change in responsiveness over time, or resistant subgroups. Our preliminary analysis suggests that the most effective agent, possibly methotrexate, should be used first if the objective is to get as many patients into remission as quickly as possible.

A staufen-like RNA-binding protein in translocation channels linking nurse cells to oocytes in Notonecta shows nucleotide-dependent attachment to microtubules

In Drosophila melanogaster the staufen gene encodes an RNA-binding protein that is essential for the correct localization of certain nurse cell-derived transcripts in oocytes. Although the mechanism underlying mRNA localization is unknown, mRNA-staufen complexes have been shown to move in a microtubule-dependent manner, and it has been suggested that staufen associates with a motor protein which generates the movement. We have investigated this possibility using Notonecta glauca in which nurse cells also supply the oocytes with mRNA, but via greatly extended nutritive tubes comprised of large aggregates of parallel microtubules. Using a staufen peptide antibody and RNA probes we have identified a staufen-like protein, which specifically binds double-stranded RNA, in the nutritive tubes of Notonecta. We show that while the staufen-like protein does not co-purify with microtubules from ovaries using standard procedures it does so under conditions of motor-entrapment, specifically in the presence of AMP-PNP. We also show that the staufen-like protein is subsequently removed by ATP and GTP, but not ADP. Nucleotide-dependent binding to microtubules is typical of a motor-mediated interaction and the pattern of attachment and detachment of the staufen-like protein correlates with that of a kinesin protein within the ovaries. Our findings indicate that the staufen-like RNA-binding protein attaches to, and is transported along, Notonecta ovarian microtubules by a kinesin motor.

A transgenic model to analyze the immunoregulatory role of IL-10 secreted by antigen-presenting cells

IL-10 is a cytokine secreted by a wide variety of cells type that has pleiotropic stimulatory and suppressive activities on both lymphoid and myeloid cells in vitro. To analyze the consequences of high IL-10 secretion by APCs in immune responses, we produced transgenic mice expressing human IL-10 directed by the MHC class II Ea promoter. Despite alterations in the development of T and B cells, no gross abnormalities were detected in peripheral lymphocyte populations or serum Ig levels. However, when immunized using conditions that give either a Th2-type or a Th1-type response, IL-10 transgenic mice failed to mount a significant T or B cell immune response to OVA. IL-10 transgenic mice were also highly susceptible to infection with intracellular pathogens like Listeria monocytogenes or Leishmania major, in contrast to IL-10 transgenic mice, where the transgene was express in T cells. Finally, the recently described stimulatory effect of IL-10 on CD8+ T cells was confirmed by the ability of IL-10 transgenic mice to limit the growth of immunogenic tumors by a CTL-mediated mechanism. These results demonstrate, that, depending on the type of immune response, IL-10 can mediate immunosuppressive or immunostimulatory activities in vivo.

Cellular distribution and molecular heterogeneity of MAC393 antigen (clusterin, beta-chain) on the surface membrane of bull spermatozoa

The distribution and size of a surface membrane antigen identified by a monoclonal antibody (MAC9393) have been examined in testicular and epididymal bovine sperm preparations. Western blots indicated a substantial decrease in molecular mass of the antigen during epididymal maturation from approximately 87 kDa in the testis to approximately 35 kDa in the cauda epididymidis. This was accompanied by a change in its cellular localization from the neck and whole head to the acrosomal region. N-terminal microsequencing identified MAC393 antigen as the beta-chain of clusterin. A polyclonal antiserum to the alpha-chain of clusterin recognized both testicular and epididymal forms and revealed that the heterodimer was present on the sperm tail as well as the acrosome. These findings are explained by the co-existence of dimeric and monomeric pools of clusterin on spermatozoa. The polyclonal antiserum recognizes both testicular and epididymal forms of the heterodimer and although the monoclonal antibody binds to the testicular heterodimer, it only recognizes the beta-chain monomer of epididymal clusterin. These findings support previous observations made on human spermatozoa that two forms of clusterin, the beta-chain monomer and the heterodimer, are present on the surface membrane and in seminal plasma.

Expression of a testis-specific putative actin-capping protein associated with the developing acrosome during rat spermiogenesis

Actin-capping proteins are ubiquitous components of mammalian cells. They are known to regulate the polymerization state of actin and hence indirectly control the activity of the cytoskeleton and cell shape. As part of our investigation into the molecular mechanisms that direct differentiation of a round spermatid into an elongating spermatozoa, we report on a testis-specific 1.7-kb transcript from rat testis with sequence similarities to the alpha subunit of actin-capping proteins (ACPs) from somatic cells. The transcript contains a putative cAMP-responsive motif (CREM) upstream of the initiation codon in the DNA sequence and is expressed postmeiotically, first appearing between 20 and 30 days of postnatal development. The primary amino acid sequence is 90% identical to that of a previously identified testis-specific mouse protein, gsg3, both showing approximately 40% homology to the alpha subunit of somatic ACPs. An affinity-purified polyclonal antibody to a synthetic peptide derived from the rat transcript identified a 32-kDa protein on Western blots of testicular extracts. Indirect immunofluorescent localization of the protein on frozen sections of adult rat testis showed that it is intracellular and accumulates asymmetrically in the cytoplasm of round spermatids coincident with the position of the developing acrosome. This spatial expression parallels the distribution of F-actin during sperm differentiation, supporting the hypothesis that testis-specific ACPs have an important role in determining the final shape of mature sperm heads. A disturbance in the expression of these ACPs may underlie many of the abnormalities in sperm morphology observed in infertile semen.

Multidisciplinary discharge planning

Patients undergoing total hip replacement need careful rehabilitation to avoid complications. Communication is essential for effective discharge planning. The named nurse is ideally placed to co-ordinate the activities of the health-care team.

Ethanol ingestion inhibits cell-mediated immune responses of unprimed T-cell receptor transgenic mice

This paper introduces a transgenic (Tg) mouse in which the majority of the CD4-bearing T cells have T-cell receptors that react with ovalbumin (OVA) as a model for ethanol research. Although these Tg animals were bred onto the BALB/c genetic background, a strain generally considered to be nonpreferring in ethanol consumption, we determined that BALB/c mice would consume an ethanol-containing liquid diet, without significant mortality, and assessed alteration of specific immune responses. BALB/c, C57BL/6 (B6), or (BALB/c x C57BL/6)F-1 hybrid (CB6F1) mice were fed LED containing 35, 30, 25, or 20% ethanol-derived calories. Significant mortality (> 40%) was seen only in BALB/c and pronounced weight loss was seen in BALB/c, B6, CB6F1 mice when they were fed the diet containing the greatest ethanol concentration (LED35). Diets containing lesser amounts of ethanol did not cause mortality. Liquid diets containing > or = 30% ethanol-derived calories significantly impaired the chicken gamma-globulin-specific delayed hypersensitivity responses in BALB/c, B6, and CB6F1mice without significantly affecting the humoral immune response to sheep red blood cells. We show that immunization of the Tg mice is not required for the development of a vigorous "delayed hypersensitivity" response to OVA or the I-Ad-restricted peptide OVA323-339 in mice fed standard solid lab chow or liquid control diet. In marked contrast, OVA Tg mice fed ethanol show a profound inhibition of this immune response, indicating that ethanol-induced inhibition of cell-mediated immunity occurs independently of antigen priming.

Synergism between interleukins 1 beta and 6 on noradrenergic nerves in rat myenteric plexus

BACKGROUND/AIMS

Because levels of interleukins 1 beta and 6 (IL-1 beta and IL-6) are elevated during intestinal Trichinella spiralis infection, they may mediate the changes in enteric neural function in that model. IL-1 beta suppresses norepinephrine release from the myenteric plexus, but the effect of IL-6 is unknown. Therefore, we investigated the effects of IL-6 alone and in combination with IL-1 beta on norepinephrine release.

METHODS

Longitudinal muscle myenteric plexus or myenteric nerve varicosity preparations from jejunum of noninfected rats were loaded with [3H]norepinephrine, and 3H release was measured after a preincubation with or without human recombinant IL-6, alone or in combination with human recombinant IL-1 beta.

RESULTS

1 ng/mL of IL-6 augmented 3H release, 100 ng/mL suppressed 3H release, whereas 10 ng/mL had no effect. However, IL-6 (10 ng/mL) plus a subthreshold concentration of human recombinant IL-1 beta significantly suppressed 3H release, and this was abolished by adding anti-IL-6 antibody or an IL-1 receptor antagonist.

CONCLUSIONS

Because 3H release reflects [3H]norepinephrine release, our results show that IL-6 exerts a dual effect on norepinephrine release. Furthermore, there is synergism between IL-1 beta and IL-6 resulting in suppression of norepinephrine release. Therefore, both cytokines may contribute to the suppression of norepinephrine release observed in the inflamed intestine.

Interleukin-1 beta modulation of norepinephrine release from rat myenteric nerves

We examined the ability of human recombinant interleukin-1 beta (hrIL-1 beta) to alter the release of [3H]norepinephrine ([3H]NE) by KCl or electrical field stimulation in longitudinal muscle-myenteric plexus of rat intestine. The cytokine had no immediate effect on either the basal or evoked release of [3H]NE. However, hrIL-1 beta caused a biphasic time-dependent suppression of evoked [3H]NE release that was delayed in onset. IL-1 beta also stimulated the cycloheximide-sensitive uptake of [35S] methionine uptake by the tissue. The initial suppression of [3H]NE release was observed after 30 min and could not be inhibited by cycloheximide. A delayed peak was observed after 120 min and was inhibited by cycloheximide. The effect of IL-1 beta was maximal at 10 ng/ml and could be prevented by a neutralizing anti-IL-1 beta antibody or by preincubating the tissue with an IL-1-receptor antagonist. These results indicate that IL-1 beta suppresses [3H]NE release from rat myenteric plexus by two mechanisms, one of which is independent of protein synthesis and the other of which is mediated by endogenous IL-1.