Toll-like receptor 4 (TLR4) antagonists as potential therapeutics for intestinal inflammation

Gastrointestinal inflammation is a hallmark of highly prevalent disorders, including cancer treatment-induced mucositis and ulcerative colitis. These disorders cause debilitating symptoms, have a significant impact on quality of life, and are poorly managed. The activation of toll-like receptor 4 (TLR4) has been proposed to have a major influence on the inflammatory signalling pathways of the intestinal tract. Inhibition of TLR4 has been postulated as an effective way to treat intestinal inflammation. However, there are a limited number of studies looking into the potential of TLR4 antagonism as a therapeutic approach for intestinal inflammation. This review surveyed available literature and reported on the in vitro, ex vivo and in vivo effects of TLR4 antagonism on different models of intestinal inflammation. Of the studies reviewed, evidence suggests that there is indeed potential for TLR4 antagonists to treat inflammation, although only a limited number of studies have investigated treating intestinal inflammation with TLR4 antagonists directly. These results warrant further research into the effect of TLR4 antagonists in the intestinal tract.

89Zr-pro-MMP-9 F(ab')2 detects colitis induced intestinal and kidney fibrosis

Intestinal fibrosis is a common complication of inflammatory bowel disease but remains difficult to detect. Matrix metalloproteases (MMPs) have key roles in fibrosis and are therefore potential targets for fibrosis detection. We determined whether immunoPET of F(ab′)₂ antibody fragments targeting MMPs detects colitis induced colonic fibrosis. Mice were administered 2% dextran sulfate sodium treated water for 1 cycle (inflamed) or 3 cycles (fibrotic), or were untreated (control). Colonic and kidney collagen, innate cytokine, MMPs and fecal MPO concentrations were analyzed by multiplex/ELISA. α-pro-MMP-9 F(ab′)₂ fragments were engineered and conjugated to ⁸⁹Zr for PET imaging, ex-vivo Cherenkov analysis and bio-distribution. Colonic innate cytokine concentrations and fecal myeloperoxidase were increased in inflamed mice but not fibrotic mice, while collagen concentrations were increased in fibrotic mice. MMPs were increased in inflamed mice, but only pro-MMP-9 remained increased in fibrotic mice. ⁸⁹Zr-pro-MMP-9 F(ab′)₂ uptake was increased in the intestine but also in the kidney of fibrotic mice, where collagen and pro-MMP-9 concentrations were increased. ⁸⁹Zr-pro-MMP-9 F(ab′)₂ detects colitis induced intestinal fibrosis and associated kidney fibrosis.

Acute Colitis Drives Tolerance by Persistently Altering the Epithelial Barrier and Innate and Adaptive Immunity

BACKGROUND

Inflammatory bowel disease (IBD) has a remitting and relapsing disease course; however, relatively little is understood regarding how inflammatory damage in acute colitis influences the microbiota, epithelial barrier, and immune function in subsequent colitis.

METHODS

Mice were administered trinitrobenzene sulphonic acid (TNBS) via enema, and inflammation was assessed 2 days (d2) or 28 days (d28) later. Colitis was reactivated in some mice by re-treating at 28 days with TNBS and assessing 2 days later (d30). Epithelial responsiveness to secretagogues, microbiota composition, colonic infiltration, and immune activation was compared between all groups.

RESULTS

At day 28, the distal colon had healed, mucosa was restored, and innate immune response had subsided, but colonic transepithelial transport (P = 0.048), regulatory T-cell (TREG) infiltration (P = 0.014), adherent microbiota composition (P = 0.0081), and responsiveness of stimulated innate immune bone marrow cells (P < 0.0001 for IL-1β) differed relative to health. Two days after subsequent instillation of TNBS (d30 mice), the effects on inflammatory damage (P < 0.0001), paracellular permeability (P < 0.0001), and innate immune infiltration (P < 0.0001 for Ly6C+ Ly6G- macrophages) were reduced relative to d2 colitis. However, TREG infiltration was increased (P < 0.0001), and the responsiveness of stimulated T cells in the mesenteric lymph nodes shifted from pro-inflammatory at d2 to immune-suppressive at d30 (P < 0.0001 for IL-10). These effects were observed despite similar colonic microbiota composition and degradation of the mucosal layer between d2 and d30.

CONCLUSIONS

Collectively, these results indicate that acute colitis chronically alters epithelial barrier function and both innate and adaptive immune responses. These effects reduce the consequences of a subsequent colitis event, warranting longitudinal studies in human IBD subjects.

Effect of Fecal Microbiota Transplantation on 8-Week Remission in Patients With Ulcerative Colitis: A Randomized Clinical Trial

IMPORTANCE

High-intensity, aerobically prepared fecal microbiota transplantation (FMT) has demonstrated efficacy in treating active ulcerative colitis (UC). FMT protocols involving anaerobic stool processing methods may enhance microbial viability and allow efficacy with a lower treatment intensity.

OBJECTIVE

To assess the efficacy of a short duration of FMT therapy to induce remission in UC using anaerobically prepared stool.

DESIGN, SETTING, AND PARTICIPANTS

A total of 73 adults with mild to moderately active UC were enrolled in a multicenter, randomized, double-blind clinical trial in 3 Australian tertiary referral centers between June 2013 and June 2016, with 12-month follow-up until June 2017.

INTERVENTIONS

Patients were randomized to receive either anaerobically prepared pooled donor FMT (n = 38) or autologous FMT (n = 35) via colonoscopy followed by 2 enemas over 7 days. Open-label therapy was offered to autologous FMT participants at 8 weeks and they were followed up for 12 months.

MAIN OUTCOMES AND MEASURES

The primary outcome was steroid-free remission of UC, defined as a total Mayo score of ≤2 with an endoscopic Mayo score of 1 or less at week 8. Total Mayo score ranges from 0 to 12 (0 = no disease and 12 = most severe disease). Steroid-free remission of UC was reassessed at 12 months. Secondary clinical outcomes included adverse events.

RESULTS

Among 73 patients who were randomized (mean age, 39 years; women, 33 [45%]), 69 (95%) completed the trial. The primary outcome was achieved in 12 of the 38 participants (32%) receiving pooled donor FMT compared with 3 of the 35 (9%) receiving autologous FMT (difference, 23% [95% CI, 4%-42%]; odds ratio, 5.0 [95% CI, 1.2-20.1]; P = .03). Five of the 12 participants (42%) who achieved the primary end point at week 8 following donor FMT maintained remission at 12 months. There were 3 serious adverse events in the donor FMT group and 2 in the autologous FMT group.

CONCLUSIONS AND RELEVANCE

In this preliminary study of adults with mild to moderate UC, 1-week treatment with anaerobically prepared donor FMT compared with autologous FMT resulted in a higher likelihood of remission at 8 weeks. Further research is needed to assess longer-term maintenance of remission and safety.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12613000236796.

Immuno-PET of Innate Immune Markers CD11b and IL-1β Detects Inflammation in Murine Colitis

Inflammatory bowel disease (IBD) is a chronic relapsing and remitting inflammatory disease of the gastrointestinal tract. The diagnosis and monitoring of IBD are reliant on endoscopy, which is invasive and does not provide information on specific mediators. Symptom flare in IBD is associated with increased activation of innate immune pathways. Immuno-PET approaches have previously demonstrated the ability to detect colitis; however, a direct comparison of antibodies targeted to innate immune mediators and cells has not been done. We aimed to compare immuno-PET of antibodies to IL-1β and CD11b against standard ¹⁸F-FDG and MRI approaches to detect colonic inflammation. Methods: Colonic concentrations of IL-1β and myeloperoxidase were determined by ELISA, and colonic infiltration by CD11b-positive CD3-negative innate immune cells was determined by flow cytometry and compared between healthy and dextran sodium sulphate-treated colitic mice. PET of ⁸⁹Zr-lα-IL-1β, ⁸⁹Zr-α-CD11b, and ¹⁸F-FDG was compared by volume-of-interest analysis and with MRI by region-of-interest analysis. Imaging results were confirmed by ex vivo biodistribution analysis. Results: Colonic inflammation was associated with impaired colonic epithelial barrier permeability, increased colonic IL-1β and myeloperoxidase concentrations, and increased CD11b-positive CD3-negative innate immune cell infiltration into the colon. ⁸⁹Zr-α-IL-1β and ⁸⁹Zr-α-CD11b immuno-PET detected colonic inflammation, as did ¹⁸F-FDG, and all PET tracers were more sensitive than MRI. Although ¹⁸F-FDG volumes of interest correlated with colitis severity and a strong trend was observed with ⁸⁹Zr-α-IL-1β, no correlation was observed for ⁸⁹Zr-α-CD11b or MRI. ⁸⁹Zr-α-IL-1β was distributed mainly to the gastrointestinal tract, whereas ⁸⁹Zr-α-CD11b was distributed to more tissue types. Conclusion: Immuno-PET using antibodies directed to innate immune markers detected colonic inflammation, with ⁸⁹Zr-α-IL-1β providing a more tissue-specific signal than ⁸⁹Zr-α-CD11b. Development of these technologies for human subjects will potentially provide a less invasive approach than endoscopy for diagnosing and monitoring IBD.

Advances in Imaging Specific Mediators of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is characterized by chronic remitting and relapsing inflammation of the lower gastrointestinal tract. The etiology underlying IBD remains unknown, but it is thought to involve a hypersensitive immune response to environmental antigens, including the microbiota. Diagnosis and monitoring of IBD is heavily reliant on endoscopy, which is invasive and does not provide information regarding specific mediators. This review describes recent developments in imaging of IBD with a focus on positron emission tomography (PET) and single-photon emission computed tomography (SPECT) of inflammatory mediators, and how these developments may be applied to the microbiota.

Colonic migrating motor complexes are inhibited in acute tri-nitro benzene sulphonic acid colitis

Background

Inflammatory Bowel Disease (IBD) is characterized by overt inflammation of the intestine and is typically accompanied by symptoms of bloody diarrhea, abdominal pain and cramping. The Colonic Migrating Motor Complex (CMMC) directs the movement of colonic luminal contents over long distances. The tri-nitrobenzene sulphonic acid (TNBS) model of colitis causes inflammatory damage to enteric nerves, however it remains to be determined whether these changes translate to functional outcomes in CMMC activity. We aimed to visualize innate immune cell infiltration into the colon using two-photon laser scanning intra-vital microscopy, and to determine whether CMMC activity is altered in the tri-nitro benzene sulphonic (TNBS) model of colitis.

Methods

Epithelial barrier permeability was compared between TNBS treated and healthy control mice in-vitro and in-vivo. Innate immune activation was determined by ELISA, flow cytometry and by 2-photon intravital microscopy. The effects of TNBS treatment and IL-1β on CMMC function were determined using a specialized organ bath.

Results

TNBS colitis increased epithelial barrier permeability in-vitro and in-vivo. Colonic IL-1β concentrations, colonic and systemic CD11b+ cell infiltration, and the number of migrating CD11b+ cells on colonic blood vessels were all increased in TNBS treated mice relative to controls. CMMC frequency and amplitude were inhibited in the distal and mid colon of TNBS treated mice. CMMC activity was not altered by superfusion with IL-1β.

Conclusions

TNBS colitis damages the epithelial barrier and increases innate immune cell activation in the colon and systemically. Innate cell migration into the colon is readily identifiable by two-photon intra-vital microscopy. CMMC are inhibited by inflammation, but this is not due to direct effects of IL-1β.

Co-expression of μ and δ opioid receptors by mouse colonic nociceptors

BACKGROUND AND PURPOSE

To better understand opioid signalling in visceral nociceptors, we examined the expression and selective activation of μ and δ opioid receptors by dorsal root ganglia (DRG) neurons innervating the mouse colon.

EXPERIMENTAL APPROACH

DRG neurons projecting to the colon were identified by retrograde tracing. δ receptor-GFP reporter mice, in situ hybridization, single-cell RT-PCR and μ receptor-specific antibodies were used to characterize expression of μ and δ receptors. Voltage-gated Ca²⁺ currents and neuronal excitability were recorded in small diameter nociceptive neurons (capacitance <30 pF) by patch clamp and ex vivo single-unit afferent recordings were obtained from the colon.

KEY RESULTS

In situ hybridization of oprm1 expression in Fast Blue-labelled DRG neurons was observed in 61% of neurons. μ and δ receptors were expressed by 36-46% of colon DRG neurons, and co-expressed by ~25% of neurons. μ and δ receptor agonists inhibited Ca²⁺ currents in DRG, effects blocked by opioid antagonists. One or both agonists inhibited action potential firing by colonic afferent endings. Incubation of neurons with supernatants from inflamed colon segments inhibited Ca²⁺ currents and neuronal excitability. Antagonists of μ, but not δ receptors, inhibited the effects of these supernatant on Ca²⁺ currents, whereas both antagonists inhibited their actions on neuronal excitability.

CONCLUSIONS AND IMPLICATIONS

A significant number of small diameter colonic nociceptors co-express μ and δ receptors and are inhibited by agonists and endogenous opioids in inflamed tissues. Thus, opioids that act at μ or δ receptors, or their heterodimers may be effective in treating visceral pain.

Colonic immune cells in irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND & AIMS

Increases in mucosal immune cells have frequently been observed in irritable bowel syndrome (IBS) patients. However, this finding is not completely consistent between studies, possibly due to a combination of methodological variability, population differences and small sample sizes. We performed a meta-analysis of case-control studies that compared immune cell counts in colonic biopsies of IBS patients and controls.

METHODS

PubMed and Embase were searched in February 2017. Results were pooled using standardized mean difference (SMD) and were considered significant when zero was not within the 95% confidence interval (CI). Heterogeneity was assessed based on I² statistics where I²  ≤ 50% and I²  > 50% indicated fixed and random effect models, respectively.

KEY RESULTS

Twenty-two studies on 706 IBS patients and 401 controls were included. Mast cells were increased in the rectosigmoid (SMD: 0.38 [95% CI: 0.06-0.71]; P = .02) and descending colon (SMD: 1.69 [95% CI: 0.65-2.73]; P = .001) of IBS patients. Increased mast cells were observed in both constipation (IBS-C) and diarrhea predominant IBS (IBS-D). CD3⁺ T cells were increased in the rectosigmoid (SMD: 0.53 [95% CI: 0.21-0.85]; P = .001) and the descending colon of the IBS patients (SMD: 0.79, 95% CI [0.28-1.30]; P = .002). This was possibly in relation to higher CD4⁺ T cells in IBS (SMD: 0.33 [95% CI: 0.01-0.65]; P = .04) as there were no differences in CD8⁺ T cells.

CONCLUSIONS & INFERENCES

Mast cells and CD3⁺ T cells are increased in colonic biopsies of patients with IBS vs non-inflamed controls. These changes are segmental and sometimes IBS-subtype dependent. The diagnostic value of the quantification of colonic mucosal cells in IBS requires further investigation.

Fluoxetine for Maintenance of Remission and to Improve Quality of Life in Patients with Crohn's Disease: a Pilot Randomized Placebo-Controlled Trial

BACKGROUND AND AIMS

Previous studies have shown that antidepressants reduce inflammation in animal models of colitis. The present trial aimed to examine whether fluoxetine added to standard therapy for Crohn's disease [CD] maintained remission, improved quality of life [QoL] and/or mental health in people with CD as compared to placebo.

METHODS

A parallel randomized double-blind placebo controlled trial was conducted. Participants with clinically established CD, with quiescent or only mild disease, were randomly assigned to receive either fluoxetine 20 mg daily or placebo, and followed for 12 months. Participants provided blood and stool samples and completed mental health and QoL questionnaires. Immune functions were assessed by stimulated cytokine secretion [CD3/CD28 stimulation] and flow cytometry for cell type. Linear mixed-effects models were used to compare groups.

RESULTS

Of the 26 participants, 14 were randomized to receive fluoxetine and 12 to placebo. Overall, 14 [54%] participants were male. The mean age was 37.4 [SD=13.2] years. Fluoxetine had no effect on inflammatory bowel disease activity measured using either the Crohn's Disease Activity Index [F(3, 27.5)=0.064, p=0.978] or faecal calprotectin [F(3, 32.5)=1.08, p=0.371], but did have modest effects on immune function. There was no effect of fluoxetine on physical, psychological, social or environmental QoL, anxiety or depressive symptoms as compared to placebo [all p>0.05].

CONCLUSIONS

In this small pilot clinical trial, fluoxetine was not superior to placebo in maintaining remission or improving QoL. [ID: ACTRN12612001067864.].

Acute colitis chronically alters immune infiltration mechanisms and sensory neuro-immune interactions

OBJECTIVE

Little is understood regarding how disease progression alters immune and sensory nerve function in colitis. We investigated how acute colitis chronically alters immune recruitment and the impact this has on re-activated colitis. To understand the impact of disease progress on sensory systems we investigated the mechanisms underlying altered colonic neuro-immune interactions after acute colitis.

DESIGN

Inflammation was compared in mouse models of health, acute tri-nitrobenzene sulphonic acid (TNBS) colitis, Remission and Reactivated colitis. Cytokine concentrations were compared by ELISA in-situ and in explanted colon tissue. Colonic infiltration by CD11b/F4-80 macrophage, CD4 T_HELPER (T_H) and CD8 T_CYTOTOXIC (T_C) and α₄β₇ expression on mesenteric lymph node (MLN) T_H and T_C was determined by flow cytometry. Cytokine and effector receptor mRNA expression was determined on colo-rectal afferent neurons and the mechanisms underlying cytokinergic effects on high-threshold colo-rectal afferent function were investigated using electrophysiology.

RESULTS

Colonic damage, MPO activity, macrophage infiltration, IL-1β and IL-6 concentrations were lower in Reactivated compared to Acute colitis. T_H infiltration and α₄β₇ expression on T_H MLN was increased in Remission but not Acute colitis. IFN-γ concentrations, T_H infiltration and α₄β₇ expression on T_H and T_C MLN increased in Reactivated compared to Acute colitis. Reactivated explants secreted more IL-1β and IL-6 than Acute explants. IL-6 and TNF-α inhibited colo-rectal afferent mechanosensitivity in Remission mice via a BK_Ca dependent mechanism.

CONCLUSIONS

Acute colitis persistently alters immune responses and afferent nerve signalling pathways to successive episodes of colitis. These findings highlight the complexity of viscero-sensory neuro-immune interactions in painful remitting and relapsing diseases.

Opioidergic effects on enteric and sensory nerves in the lower GI tract: basic mechanisms and clinical implications

Opioids are one of the most prescribed drug classes for treating acute pain. However, chronic use is often associated with tolerance as well as debilitating side effects, including nausea and dependence, which are mediated by the central nervous system, as well as constipation emerging from effects on the enteric nervous system. These gastrointestinal (GI) side effects limit the usefulness of opioids in treating pain in many patients. Understanding the mechanism(s) of action of opioids on the nervous system that shows clinical benefit as well as those that have unwanted effects is critical for the improvement of opioid drugs. The opioidergic system comprises three classical receptors (μ, δ, κ) and a nonclassical receptor (nociceptin), and each of these receptors is expressed to varying extents by the enteric and intestinal extrinsic sensory afferent nerves. The purpose of this review is to discuss the role that the opioidergic system has on enteric and extrinsic afferent nerves in the lower GI tract in health and diseases of the lower GI tract, particularly inflammatory bowel disease and irritable bowel syndrome, and the implications of opioid treatment on clinical outcomes. Consideration is also given to emerging developments in our understanding of the immune system as a novel source of endogenous opioids and the mechanisms underlying opioid tolerance, including the potential influence of opioid receptor splice variants and heteromeric complexes.

Activation of colo-rectal high-threshold afferent nerves by Interleukin-2 is tetrodotoxin-sensitive and upregulated in a mouse model of chronic visceral hypersensitivity

BACKGROUND

Chronic visceral pain is a defining feature of irritable bowel syndrome (IBS). IBS patients often show alterations in innate and adaptive immune function which may contribute to symptoms. Immune mediators are known to modulate the activity of viscero-sensory afferent nerves, but the focus has been on the innate immune system. Interleukin-2 (IL-2) is primarily associated with adaptive immune responses but its effects on colo-rectal afferent function in health or disease are unknown.

METHODS

Myeloperoxidase (MPO) activity determined the extent of inflammation in health, acute trinitrobenzene-sulfonic acid (TNBS) colitis, and in our post-TNBS colitis model of chronic visceral hypersensitivity (CVH). The functional effects of IL-2 on high-threshold colo-rectal afferents and the expression of IL-2R and NaV 1.7 mRNA in colo-rectal dorsal root ganglia (DRG) neurons were compared between healthy and CVH mice.

KEY RESULTS

MPO activity was increased during acute colitis, but subsided to levels comparable to health in CVH mice. IL-2 caused direct excitation of colo-rectal afferents that was blocked by tetrodotoxin. IL-2 did not affect afferent mechanosensitivity in health or CVH. However, an increased proportion of afferents responded directly to IL-2 in CVH mice compared with controls (73% vs 33%; p < 0.05), and the abundance of IL-2R and NaV 1.7 mRNA was increased 3.5- and 2-fold (p < 0.001 for both) in colo-rectal DRG neurons.

CONCLUSIONS & INFERENCES

IL-2, an immune mediator from the adaptive arm of the immune response, affects colo-rectal afferent function, indicating these effects are not restricted to innate immune mediators. Colo-rectal afferent sensitivity to IL-2 is increased long after healing from inflammation.

Immune derived opioidergic inhibition of viscerosensory afferents is decreased in Irritable Bowel Syndrome patients

Alterations in the neuro-immune axis contribute toward viscerosensory nerve sensitivity and symptoms in Irritable Bowel Syndrome (IBS). Inhibitory factors secreted from immune cells inhibit colo-rectal afferents in health, and loss of this inhibition may lead to hypersensitivity and symptoms. We aimed to determine the immune cell type(s) responsible for opioid secretion in humans and whether this is altered in patients with IBS. The β-endorphin content of specific immune cell lineages in peripheral blood and colonic mucosal biopsies were compared between healthy subjects (HS) and IBS patients. Peripheral blood mononuclear cell (PBMC) supernatants from HS and IBS patients were applied to colo-rectal sensory afferent endings in mice with post-inflammatory chronic visceral hypersensitivity (CVH). β-Endorphin was identified predominantly in monocyte/macrophages relative to T or B cells in human PBMC and colonic lamina propria. Monocyte derived β-endorphin levels and colonic macrophage numbers were lower in IBS patients than healthy subjects. PBMC supernatants from healthy subjects had greater inhibitory effects on colo-rectal afferent mechanosensitivity than those from IBS patients. The inhibitory effects of PBMC supernatants were more prominent in CVH mice compared to healthy mice due to an increase in μ-opioid receptor expression in dorsal root ganglia neurons in CVH mice. Monocyte/macrophages are the predominant immune cell type responsible for β-endorphin secretion in humans. IBS patients have lower monocyte derived β-endorphin levels than healthy subjects, causing less inhibition of colonic afferent endings. Consequently, altered immune function contributes toward visceral hypersensitivity in IBS.

Linaclotide inhibits colonic nociceptors and relieves abdominal pain via guanylate cyclase-C and extracellular cyclic guanosine 3',5'-monophosphate

BACKGROUND & AIMS

Linaclotide is a minimally absorbed agonist of guanylate cyclase-C (GUCY2C or GC-C) that reduces symptoms associated with irritable bowel syndrome with constipation (IBS-C). Little is known about the mechanism by which linaclotide reduces abdominal pain in patients with IBS-C.

METHODS

We determined the effects of linaclotide on colonic sensory afferents in healthy mice and those with chronic visceral hypersensitivity. We assessed pain transmission by measuring activation of dorsal horn neurons in the spinal cord in response to noxious colorectal distention. Levels of Gucy2c messenger RNA were measured in tissues from mice using quantitative reverse transcription polymerase chain reaction and in situ hybridization. We used human intestinal cell lines to measure release of cyclic guanosine-3',5'-monophosphate (cGMP) by linaclotide. We performed a post-hoc analysis of data from a phase III, double-blind, parallel-group study in which 805 patients with IBS-C were randomly assigned to groups given an oral placebo or 290 μg linaclotide once daily for 26 weeks. We quantified changes in IBS-C symptoms, including abdominal pain.

RESULTS

In mice, linaclotide inhibited colonic nociceptors with greater efficacy during chronic visceral hypersensitivity. Intra-colonic administration of linaclotide reduced signaling of noxious colorectal distention to the spinal cord. The colonic mucosa, but not neurons, was found to express linaclotide's target, GC-C. The downstream effector of GC-C, cGMP, was released after administration of linaclotide and also inhibited nociceptors. The effects of linaclotide were lost in Gucy2c(-/-) mice and prevented by inhibiting cGMP transporters or removing the mucosa. During 26 weeks of linaclotide administration, a significantly greater percentage of patients (70%) had at least a 30% reduction in abdominal pain compared with patients given placebo (50%).

CONCLUSIONS

We have identified an analgesic mechanism of linaclotide: it activates GC-C expressed on mucosal epithelial cells, resulting in the production and release of cGMP. This extracellular cGMP acts on and inhibits nociceptors, thereby reducing nociception. We also found that linaclotide reduces chronic abdominal pain in patients with IBS-C.

Sensory neuro-immune interactions differ between irritable bowel syndrome subtypes

OBJECTIVE

The gut is a major site of contact between immune and sensory systems and evidence suggests that patients with irritable bowel syndrome (IBS) have immune dysfunction. Here we show how this dysfunction differs between major IBS subgroups and how immunocytes communicate with sensory nerves.

DESIGN

Peripheral blood mononuclear cell supernatants from 20 diarrhoea predominant IBS (D-IBS) patients, 15 constipation predominant IBS (C-IBS) patients and 36 healthy subjects were applied to mouse colonic sensory nerves and effects on mechanosensitivity assessed. Cytokine/chemokine concentration in the supernatants was assessed by proteomic analysis and correlated with abdominal symptoms, and expression of cytokine receptors evaluated in colonic dorsal root ganglia neurons. We then determined the effects of specific cytokines on colonic afferents.

RESULTS

D-IBS supernatants caused mechanical hypersensitivity of mouse colonic afferent endings, which was reduced by infliximab. C-IBS supernatants did not, but occasionally elevated basal discharge. Supernatants of healthy subjects inhibited afferent mechanosensitivity via an opioidergic mechanism. Several cytokines were elevated in IBS supernatants, and levels correlated with pain frequency and intensity in patients. Visceral afferents expressed receptors for four cytokines: IL-1β, IL-6, IL-10 and TNF-α. TNF-α most effectively caused mechanical hypersensitivity which was blocked by a transient receptor potential channel TRPA1 antagonist. IL-1β elevated basal firing, and this was lost after tetrodotoxin blockade of sodium channels.

CONCLUSIONS

Distinct patterns of immune dysfunction and interaction with sensory pathways occur in different patient groups and through different intracellular pathways. Our results indicate IBS patient subgroups would benefit from selective targeting of the immune system.

TRP Channels in Visceral Pain

Visceral pain is both different and similar to somatic pain - different in being poorly localized and usually referred elsewhere to the body wall, but similar in many of the molecular mechanisms it employs (like TRP channels) and the specialization of afferent endings to detect painful stimuli. TRPV1 is sensitive to low pH. pH is lowest in gastric juice, which may cause severe pain when exposed to the oesophageal mucosa, and probably works via TRPV1. TRPV1 is found in afferent fibres throughout the viscera, and the TRPV1 agonist capsaicin can recapitulate symptoms experienced in disease. TRPV1 is also involved in normal mechanosensory function in the gut. Roles for TRPV4 and TRPA1 have also been described in visceral afferents, and TRPV4 is highly enriched in them, where it plays a major role in both mechanonociception and chemonociception. It may provide a visceral-specific nociceptor target for drug development. TRPA1 is also involved in mechano-and chemosensory function, but not as selectively as TRPV4. TRPA1 is colocalized with TRPV1 in visceral afferents, where they influence each other's function. Another modulator of TRPV1 is the cool/mint receptor TRPM8, which, when activated can abrogate responses mediated via TRPV1, suggesting that TRPM8 agonists may provide analgesia via this pathway. In all, the viscera are rich in TRP channel targets on nociceptive neurones which we hope will provide opportunities for therapeutic analgesia.

Sprouting of colonic afferent central terminals and increased spinal mitogen-activated protein kinase expression in a mouse model of chronic visceral hypersensitivity

Visceral pain following infection or inflammation is a major clinical problem. Although we have knowledge of how peripheral endings of colonic afferents change in disease, their central projections have been overlooked. With neuroanatomical tracing and colorectal distension (CRD), we sought to identify colonic afferent central terminals (CACTs), the dorsal horn (DH) neurons activated by colonic stimuli in the thoracolumbar (T10-L1) DH, and determine how they are altered by postinflammatory chronic colonic mechanical hypersensitivity. Retrograde tracing from the colon identified CACTs in the DH, whereas immunohistochemistry for phosphorylated MAP kinase ERK 1/2 (pERK) identified DH neurons activated by CRD (80 mmHg). In healthy mice, CACTs were located primarily in DH laminae I (LI) and V (LV) and projected down middle and lateral DH collateral pathways. CRD evoked pERK immunoreactivity in DH neurons, the majority of which were located in LI and LV, the same regions as CACTs. In postinflammatory mice, CACTs were significantly increased in T12-L1 compared with healthy mice. Although CACTs remained abundant in LI, they were more widespread and were now present in deeper laminae. After CRD, significantly more DH neurons were pERK-IR postinflammation (T12-L1), with abundant expression in LI and deeper laminae. In both healthy and postinflammatory mice, many pERK neurons were in close apposition to CACTs, suggesting that colonic afferents can stimulate specific DH neurons in response to noxious CRD. Overall, we demonstrate that CACT density and the number of responsive DH neurons in the spinal cord increase postinflammation, which may facilitate aberrant central representation of colonic nociceptive signaling following chronic peripheral hypersensitivity.

TRPA1 contributes to specific mechanically activated currents and sensory neuron mechanical hypersensitivity

The mechanosensory role of TRPA1 and its contribution to mechanical hypersensitivity in sensory neurons remains enigmatic. We elucidated this role by recording mechanically activated currents in conjunction with TRPA1 over- and under-expression and selective pharmacology. First, we established that TRPA1 transcript, protein and functional expression are more abundant in smaller-diameter neurons than larger-diameter neurons, allowing comparison of two different neuronal populations. Utilising whole cell patch clamping, we applied calibrated displacements to neurites of dorsal root ganglion (DRG) neurons in short-term culture and recorded mechanically activated currents termed intermediately (IAMCs), rapidly (RAMCs) or slowly adapting (SAMCs). Trpa1 deletion (–/–) significantly reduced maximum IAMC amplitude by 43% in small-diameter neurons compared with wild-type (+/+) neurons. All other mechanically activated currents in small- and large-diameter Trpa1−/− neurons were unaltered. Seventy-three per cent of Trpa1+/+ small-diameter neurons responding to the TRPA1 agonist allyl-isothiocyanate (AITC) displayed IAMCs to neurite displacement, which were significantly enhanced after AITC addition. The TRPA1 antagonist HC-030031 significantly decreased Trpa1+/+ IAMC amplitudes, but only in AITC responsive neurons. Using a transfection system we also showed TRPA1 over-expression in Trpa1+/+ small-diameter neurons increases IAMC amplitude, an effect reversed by HC-030031. Furthermore, TRPA1 introduction into Trpa1−/− small-diameter neurons restored IAMC amplitudes to Trpa1+/+ levels, which was subsequently reversed by HC-030031. In summary our data demonstrate TRPA1 makes a contribution to normal mechanosensation in a specific subset of DRG neurons. Furthermore, they also provide new evidence illustrating mechanisms by which sensitisation or over-expression of TRPA1 enhances nociceptor mechanosensitivity. Overall, these findings suggest TRPA1 has the capacity to tune neuronal mechanosensitivity depending on its degree of activation or expression.

The ion channel TRPA1 is required for normal mechanosensation and is modulated by algesic stimuli

BACKGROUND & AIMS

The transient receptor potential (TRP) channel family includes transducers of mechanical and chemical stimuli for visceral sensory neurons. TRP ankyrin 1 (TRPA1) is implicated in inflammatory pain; it interacts with G-protein-coupled receptors, but little is known about its role in the gastrointestinal (GI) tract. Sensory information from the GI tract is conducted via 5 afferent subtypes along 3 pathways.

METHODS

Nodose and dorsal root ganglia whose neurons innnervate 3 different regions of the GI tract were analyzed from wild-type and TRPA1(-/-) mice using quantitative reverse-transcription polymerase chain reaction, retrograde labeling, and in situ hybridization. Distal colon sections were analyzed by immunohistochemistry. In vitro electrophysiology and pharmacology studies were performed, and colorectal distension and visceromotor responses were measured. Colitis was induced by administration of trinitrobenzene sulphonic acid.

RESULTS

TRPA1 is required for normal mechano- and chemosensory function in specific subsets of vagal, splanchnic, and pelvic afferents. The behavioral responses to noxious colonic distension were substantially reduced in TRPA1(-/-) mice. TRPA1 agonists caused mechanical hypersensitivity, which increased in mice with colitis. Colonic afferents were activated by bradykinin and capsaicin, which mimic effects of tissue damage; wild-type and TRPA1(-/-) mice had similar direct responses to these 2 stimuli. After activation by bradykinin, wild-type afferents had increased mechanosensitivity, whereas, after capsaicin exposure, mechanosensitivity was reduced: these changes were absent in TRPA1(-/-) mice. No interaction between protease-activated receptor-2 and TRPA1 was evident.

CONCLUSIONS

These findings demonstrate a previously unrecognized role for TRPA1 in normal and inflamed mechanosensory function and nociception within the viscera.

Post-inflammatory colonic afferent sensitisation: different subtypes, different pathways and different time courses

OBJECTIVE

Intestinal infection evokes hypersensitivity in a subgroup of patients with irritable bowel syndrome (IBS) long after healing of the initial injury. Trinitrobenzene sulfonic acid (TNBS)-induced colitis in rodents likewise results in delayed maintained hypersensitivity, regarded as a model of some aspects of IBS. The colon and rectum have a complex sensory innervation, comprising five classes of mechanosensitive afferents in the splanchnic and pelvic nerves. Their plasticity may hold the key to underlying mechanisms in IBS. Our aim was therefore to determine the contribution of each afferent class in each pathway towards post-inflammatory visceral hypersensitivity.

DESIGN

TNBS was administered rectally and mice were studied after 7 (acute) or 28 (recovery) days. In vitro preparations of mouse colorectum with attached pelvic or splanchnic nerves were used to examine the mechanosensitivity of individual colonic afferents.

RESULTS

Mild inflammation of the colon was evident acutely which was absent at the recovery stage. TNBS treatment did not alter proportions of the five afferent classes between treatment groups. In pelvic afferents little or no difference in response to mechanical stimuli was apparent in any class between control and acute mice. However, major increases in mechanosensitivity were recorded from serosal afferents in mice after recovery, while responses from other subtypes were unchanged. Both serosal and mesenteric splanchnic afferents were hypersensitive at both acute and recovery stages.

CONCLUSIONS

Colonic afferents with high mechanosensory thresholds contribute to inflammatory hypersensitivity, but not those with low thresholds. Pelvic afferents become involved mainly following recovery from inflammation, whereas splanchnic afferents are implicated during both inflammation and recovery.

Post-inflammatory modification of colonic afferent mechanosensitivity

1. The present review discusses interactions between the immune and nervous systems in post-infectious irritable bowel syndrome (PI-IBS). 2. Visceral pain is the single symptom that most affects the quality of life of patients with irritable bowel syndrome (IBS), yet it is the least successfully managed. An underlying hypersensitivity of colonic afferents to mechanical stimuli has long been implicated in visceral pain in IBS, but little more is known of the physiological aetiology. 3. The PI-IBS patients are a cohort of IBS patients who attribute their symptoms to a preceding gastrointestinal infection by pathogens such as Campylobacter or Salmonella. Current evidence suggests that the immune system remains activated in these patients and contributes to their visceral hypersensitivity. This is characterized by a shift in the phenotype of circulating immune cells towards a Type 1 (Th1 predominating) state. Products from these immune cells sensitize colonic afferents to mechanical stimuli. 4. Rectal instillation of trinitrobenzene sulphonic acid induces a Th1-mediated inflammatory response, consistent with clinical observations in PI-IBS. The visceral hypersensitivity observed in this model is biphasic, with an initial onset characterized by visceral hypersensitivity correlating with histological damage followed by a delayed phase that occurs after histological recovery. Interestingly, this chronic visceral hypersensitivity is mediated by afferents in closest apposition to blood vessels, but furthest from the initial site of damage. 5. Both clinical and experimental evidence indicates that chronic dysregulation of the immune system induces visceral afferent hypersensitivity and, therefore, may be the central mechanism underlying PI-IBS.

Selective role for TRPV4 ion channels in visceral sensory pathways

BACKGROUND & AIMS

Although there are many candidates as molecular mechanotransducers, so far there has been no evidence for molecular specialization of visceral afferents. Here, we show that colonic afferents express a specific molecular transducer that underlies their specialized mechanosensory function: the transient receptor potential channel, vanilloid 4 (TRPV4).

METHODS

We found TRPV4 mRNA is highly enriched in colonic sensory neurons compared with other visceral and somatic sensory neurons. TRPV4 protein was found in colonic nerve fibers from patients with inflammatory bowel disease, and it colocalized in a subset of fibers with the sensory neuropeptide CGRP in mice. We characterized the responses of 8 subtypes of vagal, splanchnic, and pelvic mechanoreceptors.

RESULTS

Mechanosensory responses of colonic serosal and mesenteric afferents were enhanced by a TRPV4 agonist and dramatically reduced by targeted deletion of TRPV4 or by a TRP antagonist. Other subtypes of vagal and pelvic afferents, by contrast, were unaffected by these interventions. The behavioral responses to noxious colonic distention were also substantially reduced in mice lacking TRPV4.

CONCLUSIONS

These data indicate that TRPV4 contributes to mechanically evoked visceral pain, with relevance to human disease. In view of its distribution in favor of specific populations of visceral afferents, we propose that TRPV4 may present a selective novel target for the reduction of visceral pain, which is an important opportunity in the absence of current treatments.

Acid sensing ion channels 2 and 3 are required for inhibition of visceral nociceptors by benzamil

The Deg/ENaC family of ion channels, including ASIC1, 2 and 3, are candidate mechanotransducers in visceral and somatic sensory neurons, although each channel may play a different role in different sensory pathways. Here we determined which distinct populations of visceral sensory neurons are sensitive to the non-selective Deg/ENaC blocker benzamil, and which ASIC channels are targets for benzamil by studying its actions in knockout mice. Single afferent fiber recordings were made in vitro from mouse high threshold colonic thoracolumbar splanchnic afferents and low threshold gastroesophageal vagal afferents. mRNA expression of ASIC subtypes was compared between colonic and gastroesophageal afferents by quantitative RT-PCR of transcripts following laser capture microdissection of retrogradely labeled cell bodies. Mechanosensitivity of colonic afferents was potently reduced by benzamil (10(-6)-3 x 10(-4)M), whereas gastroesophageal afferents were marginally inhibited. Inhibition of colonic afferent mechanosensitivity by benzamil was markedly diminished in ASIC2-/- and ASIC3-/- mice, but unchanged in ASIC1a-/-. Therefore ASIC2 and 3 are targets for benzamil to inhibit colonic afferent mechanosensitivity. Conversely, gastroesophageal afferents are less sensitive to benzamil, and its action depends less on ASIC expression. mRNA for ASIC3 showed higher and ASIC1a showed lower relative expression in colonic afferents from thoracolumbar dorsal root ganglia than in gastric afferents from nodose (vagal) ganglia. These data indicate that ASICs on colonic afferents present distinct pharmacological targets for visceral pain.

Involvement of metabotropic glutamate 5 receptor in visceral pain

Metabotropic glutamate 5 receptor (mGluR5) antagonists are effective in animal models of inflammatory and neuropathic pain. The involvement of mGluR5 in visceral pain pathways from the gastrointestinal tract is as yet unknown. We evaluated effects of mGluR5 antagonists on the colorectal distension (CRD)-evoked visceromotor (VMR) and cardiovascular responses in conscious rats, and on mechanosensory responses of mouse colorectal afferents in vitro. Sprague-Dawley rats were subjected to repeated, isobaric CRD (12 x 80 mmHg, for 30s with 5 min intervals). The VMR and cardiovascular responses to CRD were monitored. The mGluR5 antagonists MPEP (1-10 micromol/kg, i.v.) and MTEP (1-3 micromol/kg, i.v.) reduced the VMR to CRD dose-dependently with maximal inhibition of 52+/-8% (p<0.01) and 25+/-11% (p<0.05), respectively, without affecting colonic compliance. MPEP (10 micromol/kg, i.v.) reduced CRD-evoked increases in blood pressure and heart rate by 33+/-9% (p<0.01) and 35+/-8% (p<0.05), respectively. Single afferent recordings were made from mouse pelvic and splanchnic nerves of colorectal mechanoreceptors. Circumferential stretch (0-5 g force) elicited slowly-adapting excitation of action potentials in pelvic distension-sensitive afferents. This response was reduced 55-78% by 10 microM MTEP (p<0.05). Colonic probing (2g von Frey hair) activated serosal splanchnic afferents; their responses were reduced 50% by 10 microM MTEP (p<0.01). We conclude that mGluR5 antagonists inhibit CRD-evoked VMR and cardiovascular changes in conscious rats, through an effect, at least in part, at peripheral afferent endings. Thus, mGluR5 participates in mediating mechanically evoked visceral nociception in the gastrointestinal tract.

Localization and comparative analysis of acid-sensing ion channel (ASIC1, 2, and 3) mRNA expression in mouse colonic sensory neurons within thoracolumbar dorsal root ganglia

Reducing colonic mechanosensitivity is an important potential strategy for reducing visceral pain. Mice lacking acid-sensing ion channels (ASIC) 1, 2, and 3 show altered colonic mechanosensory function, implicating ASICs in the mechanotransduction process. Deletion of ASICs affects mechanotransduction in visceral and cutaneous afferents differently, suggesting differential expression. We determined relative expression of ASIC1, 2, and 3 in mouse thoracolumbar dorsal root ganglia (DRG) by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) analysis (QPCR) and specifically in retrogradely traced colonic neurons isolated via laser capture microdissection. Localization of ASIC expression in DRG was determined with fluorescence in situ hybridization (FISH) and retrograde tracing. QPCR of whole thoracolumbar DRG revealed and abundance of ASIC2 > ASIC1 > ASIC3. Similarly, FISH of all neurons in thoracolumbar DRG demonstrated that ASIC2 was expressed in the most (40 +/- 1%) neurons, followed by ASIC3 (24 +/- 1%), then ASIC1 (18 +/- 1%). Retrograde tracing from the distal colon labeled 4 +/- 1% of neurons in T10-L1 DRG. In contrast to whole DRG, FISH of colonic neurons showed ASIC3 expression in 73 +/- 2%, ASIC2 in 47 +/- 0.5%, and ASIC1 in 30 +/- 2%. QPCR of laser captured colonic neurons revealed that ASIC3 was the most abundant ASIC transcript, followed by ASIC1, then ASIC2. We conclude that ASIC1, 2, and 3 are expressed preferentially in colonic neurons within thoracolumbar DRG. In particular ASIC3, the least abundant in the general population, is the most abundant ASIC transcript in colonic neurons. The prevalence of ASIC3 in neurons innervating the colon supports electrophysiological data showing that it makes a major contribution to colonic mechanotransduction and therefore may be a target for the treatment of visceral pain.

Toxicity of Bacillus thuringiensis var. israelensis formulations, spinosad, and selected synthetic insecticides to Chironomus tepperi larvae

Three Bacillus thuringiensis var. israelensis (BTi) formulations, the bacterial metabolite spinosad, and 7 synthetic insecticides were bioassayed against 4th instars of Chironomus tepperi, a serious pest of rice in southern Australia. The BTi formulations returned 48-h product median lethal concentration (LC50) values (25 < or = 1 degrees C) of between 0.59 mg/liter (VectoBac water-dispersible granule [WDG], 3,000 international toxic units [ITU]/mg) and 2.15 mg/liter (Teknar suspension concentrate [SC], 1,200 ITU/mg). When LC50 values were adjusted to reflect nominal ITU values of the 3 products, there was still substantial variation, with LC50 values ranging from 1,770 ITU/liter (VectoBac WDG) to 2,580 ITU/liter (Teknar SC). Aquabac SC (1,200 ITU/mg) showed intermediate activity. Differential activity between formulations may reflect faster settling rates in the more active formulations, which may be a beneficial characteristic when controlling benthic species such as C. tepperi. Spinosad (24-h LC50 = 28.9 microg active ingredient [AI]/liter) and the synthetic insecticides we evaluated were all substantially more active than BTi. The highest activity was shown by the neonicotinoid compounds thiacloprid, acetamiprid, and clothianidin, which all returned 24-h LC50 values between 1 and 3 microg AI/liter. Indoxacarb and thiomethoxam showed the lowest activity of the synthetic compounds evaluated.

Aldehyde dehydrogenase, nitric oxide synthase and superoxide in ex vivo nitrate tolerance in rat aorta

The role of aldehyde dehydrogenase (ALDH) in ex vivo tolerance to transdermal glyceryl trinitrate was explored in rat aorta. ALDH activity, measured by aldehyde-induced NADH formation, was strongly depressed in the tolerant arteries. ALDH inhibitors, chloral hydrate (0.3 mM) and cyanamide (0.1-1 mM) inhibited relaxation to glyceryl trinitrate in non-tolerant and tolerant arteries. The inhibition differed from tolerance in that (a) the glyceryl trinitrate concentration-response curve was sigmoidal cf. biphasic in tolerance, (b) the potentiating effect of nitric oxide synthase (eNOS) inhibition was unchanged cf. increased in tolerance and (c) superoxide inhibited the response cf. no significant effect in tolerant or non-tolerant arteries. Hence, reduced ALDH activity does not account fully for ex vivo tolerance. The discrepancies are consistent with evidence that (a) organic nitrates, unlike chloral and cyanamide, irreversibly inactivate ALDH (hence reduced enzyme saturability can explain the biphasic curve) and (b) eNOS contributes to tolerance by a mechanism independent of glyceryl trinitrate metabolism.

Factors affecting the toxicity of Bacillus thuringiensis var. israelensis and Bacillus sphaericus to fourth instar larvae of Chironomus tepperi (Diptera: Chironomidae)

Laboratory bioassays (48h duration, 25+/-1 degrees C) were used to determine the toxicity of Bacillus thuringiensis var. israelensis (B.t.i.) and Bacillus sphaericus to fourth instar larvae of Chironomus tepperi, a major pest of rice in southern Australia. Bioassays were conducted using different combinations of larval ages and densities to determine if these factors affected toxicity. The effects of temperature and substrate type on B.t.i. toxicity were also investigated. Tests were conducted using a commercial B.t.i. formulation (VectoBac WDG, 3000ITU/mg), a spore/crystal mixture derived from the VectoBac WDG strain, and VectoLex WDG, a commercial B. sphaericus formulation (650ITU/mg). VectoBac WDG was highly toxic to fourth instar C. tepperi in bioassays using a sand substrate (LC(50) 0.46mg/L, older larvae); younger fourth instar larvae were more susceptible (LC(50) 0.20mg/L). Increasing larval densities (from 10 to 30 per bioassay cup) increased LC(50) values for both age groups, significantly so in the case of older larvae (higher density LC(50) 0.80mg/L). Use of a soil substrate increased the LC(50) value (older larvae, 10 per cup) to 0.99mg/L. Similar differences in toxicity relative to larval age and substrate type were found in bioassays using the B.t.i. spore/crystal mixture. VectoBac WDG and the spore/crystal mixture both showed similar (approximately 6-fold) declines in activity between 30 and 17.5 degrees C. At lower temperatures (between 17.5 and 15 degrees C), activity of the spore/crystal mixture declined much more rapidly than that of VectoBac WDG. VectoLex WDG showed very low toxicity to C. tepperi larvae, and the overall impact of larval age and density was relatively minor (LC(50) values 1062-1340mg/L). Autoclaving VectoLex WDG did not substantially reduce its toxicity (LC(50) 1426mg/L), suggesting that formulation additives (i.e., surfactants and other adjuvants) are responsible for much of the toxicity occurring at the high product concentrations required to cause C. tepperi mortality. Whilst VectoLex WDG was ineffective against C. tepperi, VectoBac WDG has the potential to provide selective control of this rice pest at economically viable application rates.

The eEFIA gene family is differentially expressed in maize endosperm

eEF1A appears to be a multifunctional protein in eukaryotes, where it serves as a protein synthesis factor as well as a cytoskeletal protein. In maize endosperm, the eEF1A concentration is highly correlated with lysine content, and eEF1A synthesis is increased in opaque2 mutants compared to wild type. To investigate the basis for the increased synthesis of eEF1A in opaque2, we characterized the genes encoding this protein and measured their relative level of expression in endosperm and other tissues. Maize contains 10 to 15 eEF1A genes that are nearly identical in nucleotide and amino acid sequences. However, these genes can be distinguished based on their 3' non-coding sequences, which are less conserved. By screening endosperm and seedling cDNA libraries, we show that most of the maize eEF1A genes are expressed, and the relative level of their transcripts varies in different tissues. At least five genes are transcribed in the endosperm, and two account for ca. 80% of the RNA transcripts. The expression of several genes is enhanced in opaque2 endosperm, although the significance of this is unclear.

Candida albicans arthritis one year after successful treatment of fungemia in a healthy infant

Fungal arthritis in pediatric patients is rare and is most often associated with hematogenous spread to the affected joint. It is generally seen concomitant with, or shortly after, fungemia. We report a case of an immunocompetent patient in whom candidal arthritis developed 1 year after initial fungemia. The initial candidiasis was considered to be adequately treated with amphotericin B. The Candida isolates from the neonatal fungemia and subsequent arthritis were the some as identified by electrophoretic karyotype, restriction fragment length polymorphism analysis, and antifungal susceptibility testing. Pediatric candidal fungemia, arthritis, and their treatments are discussed.

Benign cervical leiomyoma leading to disseminated fatal malignancy

A case study is reported of incomplete excision of a sessile leiomyoma of the posterior cervix followed by rapid tumor growth of the same region in a pregnancy commencing 2 months later. Cesarean section for placenta previa was followed 10 days later by hysterectomy for massive hemorrhage. The tumor was considered, following multiple review, to be a leiomyoma of the cervix with mitosis consistent with recent pregnancy. Widespread peritoneal recurrence occurred within 3 months requiring further laparotomy for excision of widespread tumor and ligation of internal iliac arteries. Death occurred 4 weeks later with widespread peritoneal occurrence. No postmortem was performed. The case emphasizes the rare potential for malignant change in histologically benign leiomyomas with no indications to this potential apart from biological behavior.

Measles antibodies in women and infants in the vaccine era

The present investigation was done to determine whether measles enzyme immune assay (EIA) absorbency values were lower in women born in the vaccine era after 1963 and their infants in an upstate New York metropolitan area, an area of low measles incidence during the past 10 years compared with women born before the measles vaccine era who had natural measles. Aliquots of 202 sera from mother-infant pairs collected for other purposes from November 1990 to June 1991 at Albany Medical Center Hospital were tested by EIA. The demographic data available for analysis were maternal age and infant gestational age. Measles mean absorbency values were analyzed according to maternal age. Of 202 mother-infant pairs, 30% of mothers and 17% of their infants were seronegative (EIA < 0.16). Mothers born before 1963 and their infants had significantly higher mean EIA absorbency values than mothers born after 1963 and their infants (P < 0.002). The percent seropositive for measles antibodies by EIA for mothers born before 1963 and their infants, 87% and 94%, respectively, was significantly higher than the percent seropositive for mothers born after 1963 and their infants, 61% and 69%, respectively (P = 0.0001). Since the mean measles antibodies as measured by EIA absorbency were significantly lower in the mothers born after 1963 and their infants compared with women born before the vaccine era, the strategy for measles control in the future may have to include lowering the age of infant immunization.

Uroflowmetry in the puerperium

One hundred women underwent uroflowmetry once per day for the first 3 days after delivery, and the results compared to those of 53 nonpregnant controls in an effort to determine 1) whether urinary flow in the puerperium is different to that found without pregnancy, 2) whether uroflow parameters change as the puerperium progresses, and 3) which characteristics of a patient or her labour bear most influence upon the results of uroflowmetry. Urinary flow in the puerperium was seen to be different from that of the nonpregnant female in that mean flow rates were lower. In addition to this, voided volume, total flow time, and time to peak flow were all significantly increased on day 1, but were comparable on days 2 and 3. Other than for falling voided volumes, uroflow parameters did not alter significantly as the puerperium progressed. Correlation of the variables age, parity, baby weight, length of first and second stage, use of epidural and perineal suturing with the parameters of urinary flow failed to show any significant relationship.