New supporting data to guide the use of evident toxicity in acute oral toxicity studies (OECD TG 420)

Currently there are three test guidelines (TG) for acute oral toxicity studies of substances or mixtures from the Organisation for Economic Co-operation and Development (OECD). TG 423 and TG 425 use lethality as an endpoint, while TG 420 replaces death with 'evident toxicity', defined as clear signs that exposure to a higher dose would result in death. However, the perceived subjectivity of 'evident toxicity' may be preventing wider use of TG 420. To address this, the UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) and the European Partnership for Alternative Approaches to Animal Testing (EPAA) collaborated to provide recommendations on the recognition of 'evident toxicity'. Historical data from acute oral toxicity studies were analysed for clinical signs at the lower dose that could have predicted death at the higher dose. Several signs including ataxia, laboured respiration, and eyes partially closed, alone or in combination, are highly predictive. Others such as lethargy, decreased respiration, and loose faeces have lower but still appreciable positive predictive value (PPV). The data has been used to develop recommendations to promote use of TG 420 and thus reduce the suffering and numbers of animals used in acute oral toxicity studies.

A case report of tracheal tenting to the skin: An option to tracheostomy for post-thyroidectomy tracheomalacia

Operating on a huge and long-standing goiter is challenging to the surgeon and anesthetist because of the possibility of tracheomalacia and collapse of the tracheal rings after extubation. We report our innovation of tenting the trachea to the skin using sutures (passed through the strap and sternocleidomastoid muscles) to prevent post-thyroidectomy tracheomalacia.

Pan-sarbecovirus prophylaxis with human anti-ACE2 monoclonal antibodies

Human monoclonal antibodies (mAbs) that target the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein have been isolated from convalescent individuals and developed into therapeutics for SARS-CoV-2 infection. However, therapeutic mAbs for SARS-CoV-2 have been rendered obsolete by the emergence of mAb-resistant virus variants. Here we report the generation of a set of six human mAbs that bind the human angiotensin-converting enzyme-2 (hACE2) receptor, rather than the SARS-CoV-2 spike protein. We show that these antibodies block infection by all hACE2 binding sarbecoviruses tested, including SARS-CoV-2 ancestral, Delta and Omicron variants at concentrations of ~7-100 ng ml-1. These antibodies target an hACE2 epitope that binds to the SARS-CoV-2 spike, but they do not inhibit hACE2 enzymatic activity nor do they induce cell-surface depletion of hACE2. They have favourable pharmacology, protect hACE2 knock-in mice against SARS-CoV-2 infection and should present a high genetic barrier to the acquisition of resistance. These antibodies should be useful prophylactic and treatment agents against any current or future SARS-CoV-2 variants and might be useful to treat infection with any hACE2-binding sarbecoviruses that emerge in the future.

Neuropeptide regulation of non-redundant ILC2 responses at barrier surfaces

Emerging studies indicate that cooperation between neurons and immune cells regulates antimicrobial immunity, inflammation and tissue homeostasis. For example, a neuronal rheostat provides excitatory or inhibitory signals that control the functions of tissue-resident group 2 innate lymphoid cells (ILC2s) at mucosal barrier surfaces1-4. ILC2s express NMUR1, a receptor for neuromedin U (NMU), which is a prominent cholinergic neuropeptide that promotes ILC2 responses5-7. However, many functions of ILC2s are shared with adaptive lymphocytes, including the production of type 2 cytokines8,9 and the release of tissue-protective amphiregulin (AREG)10-12. Consequently, there is controversy regarding whether innate lymphoid cells and adaptive lymphocytes perform redundant or non-redundant functions13-15. Here we generate a new genetic tool to target ILC2s for depletion or gene deletion in the presence of an intact adaptive immune system. Transgenic expression of iCre recombinase under the control of the mouse Nmur1 promoter enabled ILC2-specific deletion of AREG. This revealed that ILC2-derived AREG promotes non-redundant functions in the context of antiparasite immunity and tissue protection following intestinal damage and inflammation. Notably, NMU expression levels increased in inflamed intestinal tissues from both mice and humans, and NMU induced AREG production in mouse and human ILC2s. These results indicate that neuropeptide-mediated regulation of non-redundant functions of ILC2s is an evolutionarily conserved mechanism that integrates immunity and tissue protection.

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

BACKGROUND

80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality.

METHODS

This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494.

FINDINGS

Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70-8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39-8·80) and upper-middle-income countries (2·06, 1·11-3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26-11·59) and upper-middle-income countries (3·89, 2·08-7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications.

INTERPRETATION

Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications.

FUNDING

National Institute for Health Research Global Health Research Unit.

The clinical and cost-effectiveness of a Victim Improvement Package (VIP) for the reduction of chronic symptoms of depression or anxiety in older victims of common crime (the VIP trial): study protocol for a randomised controlled trial

BACKGROUND

Older people are vulnerable to sustained high levels of psychosocial distress following a crime. A cognitive behavioural therapy (CBT)-informed psychological therapy, the Victim Improvement Package (VIP) may aid recovery. The VIP trial aims to test the clinical and cost-effectiveness of the VIP for alleviating depressive and anxiety symptoms in older victims of crime.

METHODS/DESIGN

People aged 65 years or more who report being a victim of crime will be screened by Metropolitan Police Service Safer Neighbourhood Teams within a month of the crime for distress using the Patient Health Questionnaire-2 and the Generalised Anxiety Disorder-2. Those who screen positive will be signposted to their GP for assistance, and re-screened at 3 months. Participants who screen positive for depression and/or anxiety at re-screening are randomised to a CBT informed VIP added to treatment as usual (TAU) compared to TAU alone. The intervention consists of 10 individual 1-h sessions, delivered weekly by therapists from the mental health charity Mind. The primary outcome measure is the Beck Depression Inventory-II (BDI-II) and the Beck Anxiety Inventory (BAI), used as a composite measure, assessed at 6 months after the crime (post therapy) with a 9-month post-crime follow-up. Secondary outcome measures include the EQ-5D, and a modified Client Service Receipt Inventory. A total of 226 participants will be randomised VIP:TAU with a ratio 1:1, in order to detect a standardised difference of at least 0.5 between groups, using a mixed-effects linear-regression model with 90% power and a 5% significance level (adjusting for therapist clustering and potential drop-out). A cost-effectiveness analysis will incorporate intervention costs to compare overall health care costs and quality of life years between treatment arms. An embedded study will examine the impact of past trauma and engagement in safety behaviours and distress on the main outcomes.

DISCUSSION

This trial should provide data on the clinical and cost-effectiveness of a CBT-informed psychological therapy for older victims of crime with anxiety and/or depressive symptoms and should demonstrate a model of integrated cross-agency working. Our findings should provide evidence for policy-makers, commissioners and clinicians responding to the needs of older victims of crime.

TRIAL REGISTRATION

International Standard Randomised Controlled Trials Number, ID: ISRCTN16929670. Registered on 3 August 2016.

An exploratory randomized-controlled trial of the efficacy of the Src-kinase inhibitor saracatinib as a novel analgesic for cancer-induced bone pain

Pain is a major symptom of bone metastases from advanced cancer and represents a clinical challenge to treat effectively. Basic neurobiology in preclinical animal models implicates enhanced sensory processing in the central nervous system, acting through N-methyl-D-aspartate (NMDA) glutamate receptors, as an important mechanism underpinning persistent pain. The non-receptor tyrosine kinase Src is thought to act as a hub for regulating NMDA receptor activity and the orally available Src inhibitor saracatinib has shown promise as a potential analgesic in recent animal studies. Here we tested the efficacy of saracatinib as a novel analgesic in an exploratory phase II randomized controlled trial on cancer patients with painful bone metastases. Twelve patients completed the study, with 6 receiving saracatinib 125 mg/day for 28 days and 6 receiving placebo. Pharmacokinetic measurements confirmed appropriate plasma levels of drug in the saracatinib-treated group and Src inhibition was achieved clinically by a significant reduction in the bone resorption biomarker serum cross-linked C-terminal telopeptide of type I collagen. Differences between the saracatinib and placebo groups self-reported pain scores, measured using the short form of the Brief Pain Inventory, were not clinically significant after 4 weeks of treatment. There was also no change in consumption of maintenance analgesia in the saracatinib-treated group and no improvement in Quality-of-Life scores. The data were insufficient to demonstrate saracatinib has efficacy as analgesic, although it may have a role as an anti-bone resorptive agent.

Radiopacities of the Jaws: Interpretation and Diagnosis

General dental practitioners are less confident at diagnosing radiopaque lesions of the jaws than radiolucent ones, possibly because the incidence of jaw radiopacities is comparatively low. The current review covers the majority of radiopaque lesions that are referred for a specialist opinion, and focuses on those lesions that occur commonly or those that mimic other diagnoses. The majority of radiopaque jaw lesions represent normal anatomy/normal variants or superimposed soft tissue calcifications that are typically of no clinical significance. Common pathological radiopacities of the jaws include sclerosing (condensing) osteitis, a response to low-grade chronic apical infection, and odontomes, a form of odontogenic hamartoma. The typical imaging appearances of these and other jaw radiopacities are discussed.

Effects of Src-kinase inhibition in cancer-induced bone pain

Background

Bone metastases occur frequently in advanced breast, lung, and prostate cancer, with approximately 70% of patients affected. Pain is a major symptom of bone metastases, and current treatments may be inadequate or have unacceptable side effects. The mechanisms that drive cancer-induced bone pain are not fully understood; however, it is known that there is sensitization of both peripheral bone afferents and central spinal circuits. It is well established that the N-methyl-D-aspartate receptor plays a major role in the pathophysiology of pain hypersensitivity. Inhibition of the non-receptor tyrosine kinase Src controls N-methyl-D-aspartate receptor activity and inhibiting Src reduces the hypersensitivity associated with neuropathic and inflammatory pains. As Src is also implicated in osteoclastic bone resorption, we have investigated if inhibiting Src ameliorates cancer-induced bone pain. We have tested this hypothesis using an orally bioavailable Src inhibitor (saracatinib) in a rat model of cancer-induced bone pain.

Results

Intra-tibial injection of rat mammary cancer cells (Mammary rat metastasis tumor cells -1), but not vehicle, in rats produced hindpaw hypersensitivity to thermal and mechanical stimuli that was maximal after six days and persisted for at least 13 days postinjection. Daily oral gavage with saracatinib (20 mg/kg) beginning seven days after intra-tibial injection reversed the thermal hyperalgesia but not the mechanical allodynia. The analgesic mechanisms of saracatinib appear to be due to an effect on the nervous system as immunoblotting of L2-5 spinal segments showed that mammary rat metastasis tumor cells-1 injection induced phosphorylation of the GluN1 subunit of the N-methyl-D-aspartate receptor, indicative of receptor activation, and this was reduced by saracatinib. Additionally, histology showed no anti-tumor effect of saracatinib at any dose and no significant effect on bone preservation.

Conclusions

This is the first demonstration that Src plays a role in the development of cancer-induced bone pain and that Src inhibition represents a possible new analgesic strategy for patients with bone metastases.

Experiences of the REACH testing proposals system to reduce animal testing

In order to reduce animal testing, companies registering chemical substances under the EU REACH legislation must propose rather than conduct certain tests on animals. Third parties can submit 'scientifically valid information' relevant to these proposals to the Agency responsible, the European Chemicals Agency (ECHA), who are obliged to take the information into account. The European Coalition to End Animal Experiments (ECEAE) provided comments on nearly half of the 817 proposals for vertebrate tests on 480 substances published for comment for the first REACH deadline (between 1 August 2009 and 31 July 2012). The paper summarises the response by registrants and the Agency to third party comments and highlights issues with the use of read across, in vitro tests, QSAR and weight of evidence approaches. Use of existing data and evidence that testing is legally or scientifically unjustified remain the most successful comments for third parties to submit. There is a worrying conservatism within the Agency regarding the acceptance of alternative approaches and examples of where registrants have also failed to maximise opportunities to avoid testing.

Somatosensory evoked potentials show plastic changes following a novel motor training task with the thumb

OBJECTIVE

Accumulating evidence indicates that plastic changes can be maladaptive in nature, resulting in movement and neurological disorders. The aim of this study was to further the understanding of these neurophysiological changes in sensorimotor integration (SMI) using somatosensory evoked potentials (SEPs) and concurrent performance changes following a repetitive typing task.

METHODS

SEPs were recorded following median nerve stimulation at the wrist and performed pre and post intervention. 24 participants were randomly assigned to either an intervention group which performed a 20min repetitive typing task or a control group which participated in a 20min period of mental recitation.

RESULTS

The P22-N24 amplitude increased by 59.6%, compared to only 0.96% increase following the control. The P22-N30 SEP peak amplitude increased on average 13.4% following the motor training, compared to only 0.92% following the control. Significant improvement in reaction time when comparing performance of the motor task for the intervention group was observed.

CONCLUSIONS

The N24 increase supports the involvement of cerebellar connections and the N30 increase provides further support for changes in SMI following motor learning.

SIGNIFICANCE

Combining motor training tasks with electrophysiological techniques gives insight into the mechanisms of disordered SMI and whether the changes are adaptive or maladaptive.

Temporal mismatch between pain behaviour, skin Nerve Growth factor and intra-epidermal nerve fibre density in trigeminal neuropathic pain

BACKGROUND

The neurotrophin Nerve Growth factor (NGF) is known to influence the phenotype of mature nociceptors, for example by altering synthesis of neuropeptides, and changes in NGF levels have been implicated in the pathophysiology of chronic pain conditions such as neuropathic pain. We have tested the hypothesis that after partial nerve injury, NGF accumulates within the skin and causes 'pro-nociceptive' phenotypic changes in the remaining population of sensory nerve fibres, which could underpin the development of neuropathic pain.

RESULTS

Eleven days after chronic constriction injury of the rat mental nerve the intra-epidermal nerve fibre density of the chin skin from had reduced from 11.6 ± 4.9 fibres/mm to 1.0 ± 0.4 fibres/mm; this slowly recovered to 2.4 ± 2.0 fibres/mm on day 14 and 4.0 ± 0.8 fibres/mm on day 21. Cold hyperalgesia in the ipsilateral lower lip was detectable 11 days after chronic constriction injury, although at this time skin [NGF] did not differ between sides. At 14 days post-injury, there was a significantly greater [NGF] ipsilaterally compared to contralaterally (ipsilateral = 111 ± 23 pg/mg, contralateral = 69 ± 13 pg/mg), but there was no behavioural evidence of neuropathic pain at this time-point. By 21 days post-injury, skin [NGF] was elevated bilaterally and there was a significant increase in the proportion of TrkA-positive (the high-affinity NGF receptor) intra-epidermal nerve fibres that were immunolabelled for the neuropeptide Calcitonin Gene-related peptide.

CONCLUSIONS

The temporal mismatch in behaviour, skin [NGF] and phenotypic changes in sensory nerve fibres indicate that increased [NGF] does not cause hyperalgesia after partial mental nerve injury, although it may contribute to the altered neurochemistry of cutaneous nerve fibres.

Cone beam computed tomography for imaging orbital trauma--image quality and radiation dose compared with conventional multislice computed tomography

We compared the image quality and radiation dose to the lens of the eye in patients with suspected orbital fractures who were imaged using cone beam computed tomography (CBCT) or conventional multislice computed tomography (CT). Although CBCT has a lower radiation dose than conventional CT, it is not known whether the image quality is comparable for diagnostic purposes. We identified fractures of the orbit (floor or roof, or both) in 6/10 patients who were scanned using CBCT and in 5/10 patients who were scanned using multislice CT (orbital floor and medial wall). Impingement of the rectus muscle on fracture lines was identified with both techniques, but retro-orbital haemorrhage was detected only on multislice CT. The mean radiation dose to the lens of the eye was 42% lower (range 23-53, SD 10) for CBCT than for multislice CT (p<0.001), and the effective dose (a measure of the risk of developing a radiation-induced cancer) was also significantly lower. CBCT can therefore be used to diagnose orbital fractures, and is associated with a significantly lower radiation dose than multislice CT.

Abstract 3709: Acute Stroke opens Neuronal Pannexin1 Channels

Introduction: Oxygen-glucose deprivation induces neuronal uptake of the sulforhodamine-based dye SR101 via pannexin1 channels in cultured neurons and brain slices. We assessed the hypothesis that pannexin1 channels are opened during acute stroke.

Methods: Focal cerebral ischemia was induced in male C57BL/6 mice (20 to 25g, n=5) by middle cerebral artery occlusion (MCAO) for 30 minutes using the intraluminal suture occlusion method. Brain slices (2mm thickness) were taken immediately after stroke and incubated at room temperature in oxygenated sucrose-modified artificial cerebral spinal fluid for 60 minutes in 3 μ M Texas Red hydrazide (TRH), a structurally similar SR101 analog selectively taken up by astrocytes under non-ischemic conditions. Five brain slices co-incubated with 1 mM probenecid (a specific pannexin1 channel blocker) and seven brain slices without were assessed for pannexin1 channel-mediated dye uptake. Following cryosectioning and NeuN immunofluorescent labelling, the proportion of neurons showing TRH uptake (mean percentage ± S.E.M.) was determined in both hemispheres by fluorescence microscopy from 114 regions within the dorsomedial and lateral cortex, and 54 regions within the striatum. In a separate mouse, 2-photon laser scanning microscopy was used to assess in vivo neuronal uptake of sulforhodamine B (an SR101 analog) during acute stroke. Detailed neuronal morphology following 30 minutes of MCAO was assessed in a separate group of transgenic mice (n=3, C57 background) expressing yellow fluorescent protein in a subpopulation of neocortical pyramidal neurons.

Results: Neuron morphology was unaltered after 30 minutes MCAO in the ipsilateral and contralateral hemisphere. TRH uptake was dramatically increased in the ischemic hemisphere in the lateral neocortex (ipsilateral vs contralateral 28% ± 1.8% vs 14% ± 1.6%, p < 0.0001) and striatum (ipsilateral vs contralateral 55% ± 3.0% vs 38% ± 3.1%, p = 0.005). The pannexin1-specific blocker probenecid reduced ipsilateral dye uptake to the same level seen contralaterally: (ipsilateral vs contralateral) lateral cortex 14% ± 2.5% vs 16% ± 2.6% (p = 0.58), dorsomedial cortex 13% ± 2.0% vs 16% ± 2.1% (p=0.31), and striatum 40% ± 3.2% vs 36% ± 2.2% (p=0.31). In vivo uptake of sulforhodamine B was demonstrated in neocortical and striatal neurons only in the ipsilateral hemisphere by 2-photon laser scanning microscopy.

Conclusion: The opening of neuronal pannexin1 channels is widespread specifically in ischemic tissue within 30 minutes of MCAO onset. Pannexin1 channel opening appears to precede and possibly contribute to early neuronal membrane breakdown during acute stroke.

Quantitative characterization of low-threshold mechanoreceptor inputs to lamina I spinoparabrachial neurons in the rat

It has been suggested that primary afferent C-fibres that respond to innocuous tactile stimuli are important in the sensation of pleasurable touch. Although it is known that C-tactile fibres terminate in the substantia gelatinosa (lamina II) of the spinal cord, virtually all of the neurons in this region are interneurons, and currently it is not known how impulses in C-mechanoreceptors are transmitted to higher centres. In the current study, I have tested the quantitative response properties of 'wide dynamic range' projection neurons in lamina I of the spinal cord to graded velocity brushing stimuli to identify whether low-threshold mechanoreceptor input to these neurons arises from myelinated or umyelinated nerve fibres. Graded velocity brushing stimuli (6.6-126 cm s(-1)) were used to characterize the mechanoreceptor inputs to 'wide dynamic range' neurons in lamina I of the dorsal horn that had axons that projected to the contralateral parabrachial nucleus. The most effective tactile stimuli for activation of 'wide dynamic range' lamina I spinoparabrachial neurons were low velocity brush strokes: peak discharge occurred at a mean velocity of 9.2 cm s(-1) (range 6.6-20.4 cm s(-1), s.d. 5.0 cm s(-1)), and declined exponentially as brush velocity increased. The data indicate that C-fibres, but not A-fibres, conveyed low-threshold mechanoreceptor inputs to lamina I projection neurons.

Neural organization of first optic neuropils in the littoral crab Hemigrapsus oregonensis and the semiterrestrial species Chasmagnathus granulatus

Crustaceans are among the most extensively distributed arthropods, occupying many ecologies and manifesting a great variety of compound eye optics; but in comparison with insects, relatively little is known about the organization and neuronal morphologies of their underlying optic neuropils. Most studies, which have been limited to descriptions of the first neuropil--the lamina--suggest that different species have approximately comparable cell types. However, such studies have been limited with regard to the types of neurons they identify and most omit their topographic relationships. It is also uncertain whether similarities, such as they are, are independent of visual ecologies. The present account describes and compares the morphologies and dispositions of monopolar and other efferent neurons as well as the organization of tangential and smaller centrifugal neurons in two grapsoid crabs, one from the South Atlantic, the other from the North Pacific. Because these species occupy significantly disparate ecologies we ask whether this might be reflected in differences of cell arrangements within the most peripheral levels of the visual system. The present study identifies such differences with respect to the organization of centrifugal neurons to the lamina. We also identify in both species neurons in the lamina that have hitherto not been identified in crustaceans and we draw specific comparisons between the layered organization of the grapsoid lamina and layered laminas of insects.

Sensitization of lamina I spinoparabrachial neurons parallels heat hyperalgesia in the chronic constriction injury model of neuropathic pain

It has been proposed that spinal lamina I neurons with ascending axons that project to the midbrain play a crucial role in hyperalgesia. To test this hypothesis the quantitative properties of lamina I spinoparabrachial neurons in the chronic constriction injury (CCI) model of neuropathic pain were compared to those of unoperated and sham-operated controls. Behavioural testing showed that animals with a CCI exhibited heat hyperalgesia within 4 days of the injury, and this hyperalgesia persisted throughout the 14-day post-operative testing period. In the CCI, nociceptive lamina I spinoparabrachial neurons had heat thresholds that were significantly lower than controls (43.0 ± 2.8°C vs. 46.7 ± 2.6°C; P < 10⁻⁴, ANOVA). Nociceptive lamina I spinoparabrachial neurons were also significantly more responsive to graded heat stimuli in the CCI, compared to controls (P < 0.02, 2-factor repeated-measures ANOVA), and increased after-discharges were also observed. Furthermore, the heat-evoked stimulus–response functions of lamina I spinoparabrachial neurons in CCI animals co-varied significantly (P < 0.03, ANCOVA) with the amplitude of heat hyperalgesia determined behaviourally. Taken together these results are consistent with the hypothesis that lamina I spinoparabrachial neurons have an important mechanistic role in the pathophysiology of neuropathic pain.

Understanding the Dynamics of Corporate Social Responsibility using the Concept of the Shadow Side

The paper argues for a deeper understanding of the dynamics of Corporate Social Responsibility (CSR) by examining the role of what has been called the shadow side of organisations. The use of this concept provides an alternative view of how key CSR dynamics may play out in reality. This, it is suggested, may lead to the development of an innovative framework and associated lines of vision and enquiry resulting in a deeper and more holistic understanding of the dynamics of CSR.

Supramolecular binding of protonated amines to a receptor microgel in aqueous medium

Polyanionic microgels containing negatively charged tetrazole binding sites show supramolecular binding of various protonated amines (e.g. dibucaine and spermine) in a competitive aqueous medium at millimolar concentration.

9α,11β-PGF2and its stereoisomer PGF2αare novel agonists of the chemoattractant receptor, CRTH2

CRTH2 is a recently described chemoattractant receptor for the prostaglandin, PGD(2), expressed by Th2 cells, eosinophils and basophils, and believed to play a role in allergic inflammation. Here we describe the potency of several PGD(2) metabolites at the receptor to induce cell migration and activation. We report for the first time that the PGD(2) metabolite, 9alpha,11beta-PGF(2), and its stereoisomer, PGF(2alpha), are CRTH2 agonists. 9alpha,11beta-PGF(2) is a major metabolite produced in vivo following allergen challenge, whilst PGF(2alpha) is generated independently of PGD synthetase, with implications for CRTH2 signalling in the presence or absence of PGD(2) production.

Widespread expression of the AMPA receptor GluR2 subunit at glutamatergic synapses in the rat spinal cord and phosphorylation of GluR1 in response to noxious stimulation revealed with an antigen-unmasking method

Glutamate, the principal excitatory neurotransmitter in the spinal cord, acts primarily through AMPA receptors. Although all four AMPA subunits are expressed by spinal neurons, we know little about their distribution at glutamatergic synapses. We used an antigen-unmasking technique to reveal the synaptic distribution of glutamate receptor (GluR) 1-4 subunits with confocal microscopy. After pepsin treatment, punctate staining was seen with antibodies against each subunit: GluR2-immunoreactive puncta were distributed throughout the gray matter, whereas GluR1-immunoreactive puncta were restricted to the dorsal horn and were most numerous in laminas I-II. Punctate staining for GluR3 and GluR4 was found in all laminas but was weak in superficial dorsal horn. Colocalization studies showed that GluR2 was present at virtually all (98%) puncta that were GluR1, GluR3, or GluR4 immunoreactive and that most (>90%) immunoreactive puncta in laminas IV, V, and IX showed GluR2, GluR3, and GluR4 immunoreactivity. Evidence that these puncta represented synaptic receptors was obtained with electron microscopy and by examining the association of GluR2- and GluR1-immunoreactive puncta with glutamatergic boutons (identified with vesicular glutamate transporters or markers for unmyelinated afferents). The great majority (96%) of these boutons were associated with GluR2-immunoreactive puncta. Our findings suggest that GluR2 is almost universally present at AMPA-containing synapses, whereas GluR1 is preferentially associated with primary afferent terminals. We also found a substantial, rapid increase in staining for synaptic GluR1 subunits phosphorylated on the S845 residue in the ipsilateral dorsal horn after peripheral noxious stimulation. This finding demonstrates plastic changes, presumably contributing to central sensitization, at the synaptic level.

A quantitative and morphological study of projection neurons in lamina I of the rat lumbar spinal cord

In the rat lumbar spinal cord the major supraspinal targets for lamina I projection neurons are the caudal ventrolateral medulla (CVLM), lateral parabrachial area (LPb) and periaqueductal grey matter (PAG). In this study we have estimated the number of lamina I neurons retrogradely labelled from each of these sites in the L4 segment, as well as the proportion that can be labelled by injecting different tracers into two separate sites. Our results suggest that this segment contains approximately 400 lamina I projection neurons on each side, and that approximately 85% of these can be labelled from either the CVLM or the LPb on the contralateral side. Around 120 lamina I cells in L4 project to the PAG, and over 90% of these cells can also be labelled from the CVLM or LPb. Most lamina I neurons projecting to CVLM or LPb are located in the contralateral dorsal horn, but in each case some cells were found to have bilateral projections. We also examined horizontal sections to investigate morphology and the expression of the neurokinin 1 (NK1) receptor in cells labelled from CVLM, LPb or PAG. There were no consistent morphological differences between these groups, however, while cells with strong or moderate NK1 receptor-immunostaining were labelled from LPb or CVLM, they seldom projected to the PAG. These results suggest that many lamina I cells project to more than one site in the brain and that those projecting to PAG may represent a distinct subclass of lamina I projection neuron.

Differentiation of lamina I spinomedullary and spinothalamic neurons in the cat

We characterized spinomedullary neurons that project to the ventrolateral portion of the medulla that receives lamina I terminations in two sets of experiments in the cat. First, their distribution was examined using single unilateral iontophoretic injections of cholera toxin subunit B. The injection sites were characterized by microelectrode recordings from nociceptive- and thermoreceptive-specific units, indicative of lamina I input. The spinomedullary neurons were symmetrically distributed bilaterally, predominantly (63-69%) in lamina I but also in laminae V-VIII and the thoracic lateral horn (intermediolateral cell column). In horizontal sections, spinomedullary lamina I neurons included all three main morphological types described earlier. Second, spinomedullary and spinothalamic neurons were compared in retrograde double-labeling experiments. Different combinations of tracers were injected in the right thalamus and the left or right ventrolateral medulla (guided by recordings). The numbers of spinomedullary and spinothalamic neurons on the left side were comparable, and the segmental and laminar distributions were similar, except that a greater proportion of spinomedullary neurons originated from thoracic segments. However, the proportion of double-labeled neurons was consistently approximately 1%, indicating that spinomedullary and spinothalamic pathways arise from separate subpopulations. Spinomedullary neurons were more ventrally located within lamina I than spinothalamic neurons. A significantly greater proportion of spinomedullary neurons had fusiform somata (49% vs. 36%). These observations indicate that lamina I is the major source of spinal input to this portion of the ventrolateral medulla, that the projection includes several morphological types of inputs, and that this projection is distinct from the spinothalamic projection. These findings are consistent with the concept that lamina I projections constitute an ascending homeostatic afferent pathway relating the physiological condition of the body.

Quantitative responses of spinothalamic lamina I neurones to graded mechanical stimulation in the cat

Nociceptive spinothalamic tract (STT) neurones in lamina I of the lumbosacral spinal cord of anaesthetized cats were characterized by recording their responses to graded mechanical stimulation with controlled forces of 10-120 g and probes of 5.0, 0.5 and 0.1 mm(2) contact area. Neurones were identified by antidromic activation from the contralateral thalamus, and cells that responded to noxious stimulation were categorized as either nociceptive specific (NS, n = 20) or as polymodal nociceptive (HPC, responsive to heat, pinch and cold, n = 19) based on their responses to quantitative thermal stimuli. The mean responses of the 39 units increased linearly as stimulus intensity increased, and the population stimulus-response curves evoked by each of the three probes were all significantly different from each other. Thresholds were 45 g for the 5.0 mm(2) probe, 30 g for the 0.5 mm(2) probe and 20 g for the 0.1 mm(2) probe. Further analysis showed that the NS neurones encoded both stimulus intensity and area (probe size) significantly better than HPC neurones in terms of their thresholds to individual probes, their peak discharge rates, their suprathreshold responsiveness and their ability to discriminate the three different probe sizes. These differences are consistent with the known differences between the mechanical encoding properties of A-fibre nociceptors, which provide the dominant inputs to NS neurones, and C-fibre nociceptors, which are the dominant inputs to HPC cells. Comparison of the stimulus-response curves of NS and HPC neurones indicated that the discharge of NS neurones better match the psychophysics of mechanical pain sensations in humans than the discharge of the HPC neurones do. Our findings support the view that NS neurones have a prominent role in mechanical pain and sharpness, and they corroborate the concept that the lamina I STT projection comprises several discrete channels that are integrated in the forebrain to generate qualitatively distinct sensations.

Properties of single nerve fibres that evoke blood flow changes in cat dental pulp

Single nerve fibres innervating tooth pulp were isolated from filaments dissected from the inferior alveolar nerve in 17 anaesthetized cats. The fibres were studied to determine whether electrical stimulation of single units produced detectable changes in pulpal blood flow. Single pulpal nerve fibres were electrically stimulated at just above their thresholds and blood flow was recorded with a laser-Doppler flow meter from the pulp of the ipsilateral canine. The thresholds of single fibres in dissected filaments were determined either by recording antidromic action potentials from the tooth or by using a novel technique based on collision. Units that produced blood flow changes were further characterized by recording their response to hot, cold, osmotic and hydrostatic pressure, and mechanical stimulation of exposed dentine and to drying the dentine. Of 93 units isolated, 14 produced changes in pulpal blood flow when stimulated electrically at 1 or 10 Hz. All had conduction velocities (0.8-2.0 m s(-1)) in the C-fibre range. Ten produced vasodilatation and the remaining four, vasoconstriction. Five of the fibres that produced vasodilatation also responded to the hot stimulus, suggesting that they may form part of an axon reflex or similar mechanism. The four vasoconstrictor units did not respond to any form of stimulus other than electrical and were presumed to be sympathetic post-ganglionic fibres.

Responses of spinothalamic lamina I neurons to maintained noxious mechanical stimulation in the cat

Noxious mechanical stimuli that are maintained for minutes produce a continuous sensation of pain in humans that augments during the stimulus. It has recently been shown with systematic force-controlled stimuli that, while all mechanically responsive nociceptors adapt to these stimuli, the basis for such pain can be ascribed to A-fiber rather than C-fiber nociceptors, based on distinctions in their respective response profiles and stimulus-response functions. The present experiments investigated whether similar distinctions could be made in subsets of nociceptive lamina I spinothalamic tract (STT) neurons using similar maintained stimuli. Twenty-eight lamina I STT neurons in the lumbosacral dorsal horn of barbiturate-anesthetized cats were tested with noxious mechanical stimuli applied with a probe of 0.1 mm(2) contact area at forces of 25, 50, and 100 g for 2 min. The neurons were classified as nociceptive-specific (NS, n = 14) or polymodal nociceptive (HPC, n = 14) based on their responses to quantitative thermal stimuli. The NS neurons had greater responses and showed less adaptation than the HPC neurons in response to these stimuli, and they encoded stimulus intensity better. Comparison of the normalized response profiles of all 28 nociceptive lamina I STT neurons, independent of cell classification, revealed 2 subgroups that differed significantly: "Maintained" cells with responses that remained above 50% of the initial peak rate during stimulation and "Adapting" cells with responses that quickly declined to <50%. The Maintained neurons encoded the intensity of the mechanical stimuli better than the Adapting neurons, based on ratiometric functions. A k-means cluster analysis of all 28 cells distinguished the identical two subgroups. These categories corresponded closely to the NS and HPC categories: Maintained cells were mostly NS neurons (10 NS, 3 HPC), and Adapting cells were mostly HPC neurons (4 NS, 11 HPC). Thus the present data are consistent with the distinctions between A-fiber and C-fiber nociceptors observed previously, because A-fiber nociceptors are the predominant input to NS lamina I STT neurons and C-fiber nociceptors are the predominant input to HPC neurons. These findings support the view that NS, but perhaps not HPC, lamina I STT neurons have a role in the pain caused by maintained mechanical stimuli and contribute to the sensations of "first" pain and "sharpness." Nonetheless, none of the units studied showed increasing responses during the stimuli, suggesting a role for other ascending neurons or forebrain integration in the augmenting pain produced by maintained mechanical stimulation.

Responses of spinothalamic lamina I neurons to repeated brief contact heat stimulation in the cat

It was recently shown that repeated heat stimulation, using brief contacts (<1 s) with a preheated thermode at sufficiently short interstimulus intervals (ISIs <5 s) and high temperatures (> or =51 degrees C), will elicit in humans a sensation of rapidly augmenting "second" (burning) pain with only a weak "first" (sharp) pain sensation. Most strikingly, at short intertrial intervals (ITIs >5 s) such summation will reset, or begin again at baseline. In the present experiments, the responses of nociceptive lamina I spinothalamic (STT) neurons in the lumbosacral dorsal horn of barbiturate-anesthetized cats were examined using this repeated brief contact heat paradigm. The neurons were classified as nociceptive-specific (NS, n = 8) or polymodal nociceptive (HPC, n = 8) based on their responses to quantitative thermal stimuli; all had receptive fields on the glabrous ventral hindpaw. A pneumatic piston was used to apply a thermode preheated to 34, 46, 49, 53, or 58 degrees C with a contact dwell time of approximately 0.7 s to the ventral hindpaw repeatedly (15 times) at ISIs of 2, 3, and 5 s, with 3-5 min between trials. The mean responses of the 16 nociceptive lamina I STT cells showed rapid temporal summation that was directly dependent on temperature and inversely dependent on ISI, with the greatest increases occurring between the 3rd and 10th contacts. The temporal profiles of this family of curves correspond with the psychophysical data on human sensation. Further analysis showed that this summation was due to the HPC cells, which all showed strong summation; in contrast, the NS cells showed little, if any. The HPC responses to the repeated heat stimuli lagged each contact by approximately 1 s, consistent with the strong, monosynaptic C-fiber input that is characteristic of HPC cells and also with the dependence of second pain on C-fiber nociceptors. HPC cells also displayed the reset phenomenon at short ITIs, again in correspondence with the psychophysical data. The summation and the reset displayed by HPC cells were not related to skin temperature. Thus the results presented in this study, together with those in the preceding article, demonstrate a double dissociation indicating that NS and HPC lamina I STT cells can subserve the qualitatively distinct sensations of first (sharp) and second (burning) pain, respectively. These findings support the concept that the lamina I STT projection comprises several discrete sensory channels that are integrated in the forebrain to generate distinct sensations.

Activation of spinobulbar lamina I neurons by static muscle contraction

Spinal lamina I neurons are selectively activated by small-diameter somatic afferents, and they project to brain stem sites that are critical for homeostatic control. Because small-diameter afferent activity evoked by contraction of skeletal muscle reflexly elicits exercise-related cardiorespiratory activation, we tested whether spinobulbar lamina I cells respond to muscle contraction. Spinobulbar lamina I neurons were identified in chloralose-anesthetized cats by antidromic activation from the ipsilateral caudal ventrolateral medulla. Static contractions of the ipsilateral triceps surae muscle were evoked by tibial nerve stimulation using parameters that avoid afferent activation, and arterial blood pressure responses were recorded. Recordings were maintained from 13 of 17 L(7) lamina I spinobulbar neurons during static muscle contraction, and 5 of these neurons were excited. Three were selectively activated only by muscle afferents and did not have a cutaneous receptive field. Spinobulbar lamina I neurons activated by muscle contraction provide an ascending link for the reflex cardiorespiratory adjustments that accompany muscular work. This study provides an important first step in elucidating an ascending afferent pathway for somato-autonomic reflexes.

Spinothalamic lamina I neurones selectively responsive to cutaneous warming in cats

1. In order to further characterize the role of lamina I as the source of central ascending neural pathways for thermoreception and thermoregulation, experiments were performed on anaesthetized cats to determine the quantitative response characteristics of warming-specific lumbosacral spinothalamic lamina I neurones. 2. We identified 10 neurones out of 474 that were selectively excited by cutaneous warming (Warm cells). Their thresholds were all in the range 35-37 degrees C at a baseline of 34.5 degrees C, and their discharge linearly encoded the temperature of graded, innocuous warming stimuli with a sensitivity of 2.1 Hz x degrees C(-1). 3. The stimulus-response function of the Warm cells plateaued at temperatures that were in the noxious heat range. 4. The Warm cells were distinguished from other classes of spinothalamic lamina I neurones by their peripheral inputs, central conduction velocities and level of ongoing activity. 5. The discharge of Warm cells compares well with the known human psychophysics of warm sensibility, and these neurones are likely to be crucial to discriminative thermoreception. Additionally, a role in thermoregulation, a defining feature of mammalian homeostasis, is suggested.

Age-associated thymic atrophy is not associated with a deficiency in the CD44(+)CD25(-)CD3(-)CD4(-)CD8(-) thymocyte population

Age-associated thymic atrophy has been proposed to be due to changes in both the thymic microenvironment and in the intrinsic properties of the early T cell progenitors, the CD44(+)CD25(-)CD3(-)CD4(-)CD8(-) cells. We have purified these cells from the thymus of both old and young mice and demonstrate no age-associated defect in their ability to differentiate into their progeny in vitro when used to reconstitute fetal thymic organ cultures. We also demonstrate that in the presence of anti-IL-7, CD44(+)CD25(-)CD3(-)CD4(-)CD8(-) cells from young mice show reduced thymocyte development in fetal thymic organ cultures compared with controls. Finally we have shown that old mice treated with IL-7 show improved thymopoiesis compared with control groups. The increased thymopoiesis seen in the old animals occurs in the sequential manner which would be anticipated for an agent working directly on the early stages, including the CD44(+)CD25(-)CD3(-)CD4(-)CD8(-) cells.

Quantitative response characteristics of thermoreceptive and nociceptive lamina I spinothalamic neurons in the cat

The physiological characteristics of antidromically identified lamina I spinothalamic (STT) neurons in the lumbosacral spinal cord were examined using quantitative thermal and mechanical stimuli in barbiturate-anesthetized cats. Cells belonging to the three main recognized classes were included based on categorization with natural cutaneous stimulation of the hindpaw: nociceptive-specific (NS), polymodal nociceptive (HPC), or thermoreceptive-specific (COOL) cells. The mean central conduction latencies of these classes differed significantly; NS = 130.8 +/- 55.5 (SD) ms (n = 100), HPC = 72.1 +/- 28.0 ms (n = 128), and COOL = 58.6 +/- 25.3 ms (n = 136), which correspond to conduction velocities of 2.5, 4.6, and 5.6 m/s. Based on recordings made prior to any noxious stimulation, the mean spontaneous discharge rates of these classes also differed: NS = 0.5 +/- 0.7 imp/s (n = 47), HPC = 0.9 +/- 0.7 imp/s (n = 59), and COOL = 3.3 +/- 2.6 imp/s (n = 107). Standard, quantitative, thermal stimulus sequences applied with a Peltier thermode were used to characterize the stimulus-response functions of 76 COOL cells, 47 HPC cells, and 37 NS cells. The COOL cells showed a very linear output from 34 degrees C down to approximately 15 degrees C and a maintained plateau thereafter. The HPC cells showed a fairly linear but accelerating response to cold below a median threshold of approximately 24 degrees C and down to 9 degrees C (measured at the skin-thermode interface with a thermode temperature of 2 degrees C). The HPC cells and the NS cells both showed rapidly increasing, sigmoidal response functions to noxious heat with a fairly linear response between 45 and 53 degrees C, but they had significantly different thresholds; half of the HPC cells were activated at ~45.5 degrees C and half of the NS cells at approximately 43 degrees C. The 20 HPC lamina I STT cells and 10 NS cells tested with quantitative pinch stimuli showed fairly linear responses above a threshold of approximately 130 g/mm(2) for HPC cells and a threshold of approximately 100 g/mm(2) for NS cells. All of these response functions compare well (across species) with the available data on the characteristics of thermoreceptive and nociceptive primary afferent fibers and the appropriate psychophysics in humans. Together these results support the concept that these classes of lamina I STT cells provide discrete sensory channels for the sensations of temperature and pain.

Bromelain modulates T cell and B cell immune responses in vitro and in vivo

The ability to modulate immune responses is a major aim of many vaccine and immunotherapeutic development programs. Bromelain, a mixture of cysteine proteases, modulates immunological responses and has been proposed to be of clinical use. However, the identity of the immune cells affected by bromelain and the specific cellular functions that are altered remain poorly understood. To address these shortcomings in our knowledge, we have used both in vitro and in vivo immunological assays to study the effects of bromelain. We found that bromelain enhanced T cell receptor (TCR) and anti-CD28-mediated T cell proliferation in splenocyte cultures by increasing the costimulatory activity of accessory cell populations. However, despite increased T cell proliferation, bromelain concomitantly decreased IL-2 production in splenocyte cultures. Additionally, bromelain did not affect TCR and CD28-induced proliferation of highly purified CD4+ T cells, but did inhibit IL-2 production by these cells. In vivo, bromelain enhanced T-cell-dependent, Ag-specific, B cell antibody responses. Again, bromelain induced a concomitant decrease in splenic IL-2 mRNA accumulation in immunized mice. Together, these data show that bromelain can simultaneously enhance and inhibit T cell responses in vitro and in vivo via a stimulatory action on accessory cells and a direct inhibitory action on T cells. This work provides important insights into the immunomodulatory activity of bromelain and has important implications for the use of exogenous cysteine proteases as vaccine adjuvants or immunomodulatory agents.

Bromelain activates murine macrophages and natural killer cells in vitro

The innate immune response is critical for effective immunity against most pathogens. In this study, we show that bromelain, a mixture of cysteine proteases, can enhance IFN-gamma-mediated nitric oxide and TNFalpha production by macrophages. Bromelain's effect was independent of endotoxin receptor activation and was not caused by direct modulation of IFN-gamma receptors. Instead, bromelain either enhanced or acted synergistically with IFN-gamma receptor-mediated signals. These effects were seen in both RAW 264.7, a macrophage cell line, and primary macrophage populations. Bromelain also increased IL-2- and IL-12-mediated IFN-gamma production by NK cells. These results indicate a potential role for bromelain in the activation of inflammatory responses in situations where they may be deficient, such as may occur in immunocompromised individuals.