Search

Background: Neonates and infants requiring anaesthesia are at risk of physiological instability and complications, but triggers for peri-anaesthetic interventions and associations with subsequent outcome are unknown., Methods: This prospective, observational study recruited patients up to 60 weeks' postmenstrual age undergoing anaesthesia for surgical or diagnostic procedures from 165 centres in 31 European countries between March 2016 and January 2017. The primary aim was to identify thresholds of pre-determined physiological variables that triggered a medical intervention. The secondary aims were to evaluate morbidities, mortality at 30 and 90 days, or both, and associations with critical events., Results: Infants (n=5609) born at mean (standard deviation [sd]) 36.2 (4.4) weeks postmenstrual age (35.7% preterm) underwent 6542 procedures within 63 (48) days of birth. Critical event(s) requiring intervention occurred in 35.2% of cases, mainly hypotension (>30% decrease in blood pressure) or reduced oxygenation (SpO 2 <85%). Postmenstrual age influenced the incidence and thresholds for intervention. Risk of critical events was increased by prior neonatal medical conditions, congenital anomalies, or both (relative risk [RR]=1.16; 95% confidence interval [CI], 1.04-1.28) and in those requiring preoperative intensive support (RR=1.27; 95% CI, 1.15-1.41). Additional complications occurred in 16.3% of patients by 30 days, and overall 90-day mortality was 3.2% (95% CI, 2.7-3.7%). Co-occurrence of intraoperative hypotension, hypoxaemia, and anaemia was associated with increased risk of morbidity (RR=3.56; 95% CI, 1.64-7.71) and mortality (RR=19.80; 95% CI, 5.87-66.7)., Conclusions: Variability in physiological thresholds that triggered an intervention, and the impact of poor tissue oxygenation on patient's outcome, highlight the need for more standardised perioperative management guidelines for neonates and infants., Clinical Trial Registration: NCT02350348., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Asthma treatment guidelines recommend increasing corticosteroid dose to control symptoms and reduce exacerbations. This approach is potentially flawed because symptomatic asthma can occur without corticosteroid responsive type-2 (T2)-driven eosinophilic inflammation, and inappropriately high-dose corticosteroid treatment might have little therapeutic benefit with increased risk of side-effects. We compared a biomarker strategy to adjust corticosteroid dose using a composite score of T2 biomarkers (fractional exhaled nitric oxide [FENO], blood eosinophils, and serum periostin) with a standardised symptom-risk-based algorithm (control)., Methods: We did a single-blind, parallel group, randomised controlled trial in adults (18-80 years of age) with severe asthma (at treatment steps 4 and 5 of the Global Initiative for Asthma) and FENO of less than 45 parts per billion at 12 specialist severe asthma centres across England, Scotland, and Northern Ireland. Patients were randomly assigned (4:1) to either the biomarker strategy group or the control group by an online electronic case-report form, in blocks of ten, stratified by asthma control and use of rescue systemic steroids in the previous year. Patients were masked to study group allocation throughout the entirety of the study. Patients attended clinic every 8 weeks, with treatment adjustment following automated treatment-group-specific algorithms: those in the biomarker strategy group received a default advisory to maintain treatment and those in the control group had their treatment adjusted according to the steps indicated by the trial algorithm. The primary outcome was the proportion of patients with corticosteroid dose reduction at week 48, in the intention-to-treat (ITT) population. Secondary outcomes were inhaled corticosteroid (ICS) dose at the end of the study; cumulative dose of ICS during the study; proportion of patients on maintenance oral corticosteroids (OCS) at study end; rate of protocol-defined severe exacerbations per patient year; time to first severe exacerbation; number of hospital admissions for asthma; changes in lung function, Asthma Control Questionnaire-7 score, Asthma Quality of Life Questionnaire score, and T2 biomarkers from baseline to week 48; and whether patients declined to progress to OCS. A secondary aim of our study was to establish the proportion of patients with severe asthma in whom T2 biomarkers remained low when corticosteroid therapy was decreased to a minimum ICS dose. This study is registered with ClinicalTrials.gov, NCT02717689 and has been completed., Findings: Patients were recruited from Jan 8, 2016, to July 12, 2018. Of 549 patients assessed, 301 patients were included in the ITT population and were randomly assigned to the biomarker strategy group (n=240) or to the control group (n=61). 28·4% of patients in the biomarker strategy group were on a lower corticosteroid dose at week 48 compared with 18·5% of patients in the control group (adjusted odds ratio [aOR] 1·71 [95% CI 0·80-3·63]; p=0·17). In the per-protocol (PP) population (n=121), a significantly greater proportion of patients were on a lower corticosteroid dose at week 48 in the biomarker strategy group (30·7% of patients) compared with the control group (5·0% of patients; aOR 11·48 [95% CI 1·35-97·83]; p=0·026). Patient choice to not follow treatment advice was the principle reason for loss to PP analysis. There was no difference in secondary outcomes between study groups and no loss of asthma control among patients in the biomarker strategy group who reduced their corticosteroid dose., Interpretation: Biomarker-based corticosteroid adjustment did not result in a greater proportion of patients reducing corticosteroid dose versus control. Understanding the reasons for patients not following treatment advice in both treatment strategies is an important area for future research. The prevalence of T2 biomarker-low severe asthma was low., Funding: This study was funded, in part, by the Medical Research Council UK., (Copyright © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Pain experienced during neonatal intensive care management can influence neurodevelopmental outcome and the somatosensory and/or emotional components of pain response in later life. Alterations in biological factors (e.g. peripheral and central somatosensory function and modulation, brain structure and connectivity) and psychosocial factors (e.g. gender, coping style, mood, parental response) that influence pain have been identified in children and young adults born very preterm or extremely preterm. Earlier gestational age at birth and cumulative pain exposure from tissue-breaking procedures and/or neonatal surgery influence the degree of change. In neonatal rodents, repeated needle insertion or hindpaw incision identify developmentally-regulated and activity-dependent long term alterations in nociceptive processing, and the efficacy of novel or current analgesic interventions can be compared. As prior neonatal experience and sex may influence current pain experience or the risk of persistent pain, these factors should be considered within the biopsychosocial assessment and formulation of pain in later life., (© 2019 Published by Elsevier Ltd.)

Background: Conditioned pain modulation is a potential biomarker for risk of persistent pain. As early-life experience can alter subsequent somatosensory processing and pain response, we evaluated conditioned pain modulation after extremely preterm birth., Methods: This observational study recruited extremely preterm (<26 weeks gestation; n=98) and term-born control (n=48) young adults (19-20 yr) from the longitudinal EPICure cohort. Pressure pain threshold (PPT; variable test stimulus lower leg) was measured before, during, and after a conditioning stimulus (contralateral hand immersion; 5°C water; 30 s). Questionnaires assessed current pain, medication use, anxiety, and pain catastrophising., Results: For participants tolerating conditioning, there were significant main effects of extremely preterm status, sex, and time on PPT during and after hand immersion. Inhibitory modulation was evoked in 64/98 extremely preterm (3, no change) and 38/48 term-born control (3, facilitation) subjects. The conditioned pain modulation effect (percentage change in PPT) did not differ between the extremely preterm and term-born control groups {53% [95% confidence interval (CI): 41-65] vs 57% [95% CI: 42-71]}. Reduced cold tolerance (<20 s) hampered conditioned pain modulation quantification in a higher proportion of extremely preterm participants [extremely preterm vs term-born control: 31/98 (32%) vs 7/48 (15%); P=0.03]. One-third of extremely preterm females withdrew the hand before parallel PPT (<15 s), and had lower baseline PPT than term-born control females [4.9 (95% CI: 4.8-5.1) vs 5.3 (95% CI: 5.1-5.5) ln kPa; P=0.02]. Higher anxiety, pain catastrophising, and medication use correlated with pain intensity, but not conditioned pain modulation effect., Conclusions: Cold conditioning evoked inhibitory modulation in the majority of young adults and identified a subgroup of extremely preterm females with increased baseline sensitivity. Early-life experience and sex/gender should be considered when evaluating persistent pain risk with conditioned pain modulation., (Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Surgery or multiple procedural interventions in extremely preterm neonates influence neurodevelopmental outcome and may be associated with long-term changes in somatosensory function or pain response., Methods: This observational study recruited extremely preterm (EP, <26 weeks' gestation; n=102, 60% female) and term-born controls (TC; n=48) aged 18-20 yr from the UK EPICure cohort. Thirty EP but no TC participants had neonatal surgery. Evaluation included: quantitative sensory testing (thenar eminence, chest wall); clinical pain history; questionnaires (intelligence quotient; pain catastrophising; anxiety); and structural brain imaging., Results: Reduced thermal threshold sensitivity in EP vs TC participants persisted at age 18-20 yr. Sex-dependent effects varied with stimulus intensity and were enhanced by neonatal surgery, with reduced threshold sensitivity in EP surgery males but increased sensitivity to prolonged noxious cold in EP surgery females (P<0.01). Sex-dependent differences in thermal sensitivity correlated with smaller amygdala volume (P<0.05) but not current intelligence quotient. While generalised decreased sensitivity encompassed mechanical and thermal modalities in EP surgery males, a mixed pattern of sensory loss and sensory gain persisted adjacent to neonatal scars in males and females. More EP participants reported moderate-severe recurrent pain (22/101 vs 4/48; χ 2 =0.04) and increased pain intensity correlated with higher anxiety and pain catastrophising., Conclusions: After preterm birth and neonatal surgery, different patterns of generalised and local scar-related alterations in somatosensory function persist into early adulthood. Sex-dependent changes in generalised sensitivity may reflect central modulation by affective circuits. Early life experience and sex/gender should be considered when evaluating somatosensory function, pain experience, or future chronic pain risk., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Nociceptive input during early development can produce somatosensory memory that influences future pain response. Hind-paw incision during the 1st postnatal week in the rat enhances re-incision hyperalgesia in adulthood. We now evaluate its modulation by neonatal analgesia., Methods: Neonatal rats [Postnatal Day 3 (P3)] received saline, intrathecal morphine 0.1 mg kg-1 (IT), subcutaneous morphine 1 mg kg -1 (SC), or sciatic levobupivacaine block (LA) before and after plantar hind-paw incision (three×2 hourly injections). Six weeks later, behavioural thresholds and electromyography (EMG) measures of re-incision hyperalgesia were compared with an age-matched adult-only incision (IN) group. Morphine effects on spontaneous (conditioned place preference) and evoked (EMG sensitivity) pain after adult incision were compared with prior neonatal incision and saline or morphine groups. The acute neonatal effects of incision and analgesia on behavioural hyperalgesia at P3 were also evaluated., Results: Adult re-incision hyperalgesia was not prevented by neonatal peri-incision morphine (saline, IT, and SC groups > IN; P<0.05-0.01). Neonatal sciatic block, but not morphine, prevented the enhanced re-incision reflex sensitivity in adulthood (LA < saline and morphine groups, P<0.01; LA vs IN, not significant). Morphine efficacy in adulthood was altered after morphine alone in the neonatal period, but not when administered with neonatal incision. Morphine prevented the acute incision-induced hyperalgesia in neonatal rats, but only sciatic block had a preventive analgesic effect at 24 h., Conclusions: Long-term effects after neonatal injury highlight the need for preventive strategies. Despite effective analgesia at the time of neonatal incision, morphine as a sole analgesic did not alter the somatosensory memory of early-life surgical injury., (Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Radiotherapy is an effective treatment of intermediate/high-risk locally advanced prostate cancer, however, >30% of patients relapse within 5 years. Clinicopathological parameters currently fail to identify patients prone to systemic relapse and those whom treatment intensification may be beneficial. The purpose of this study was to independently validate the performance of a 70-gene Metastatic Assay in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and androgen deprivation therapy., Patients and Methods: A bridging cohort of prostate cancer diagnostic biopsy specimens was profiled to enable optimization of the Metastatic Assay threshold before further independent clinical validation in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and androgen deprivation therapy. Multivariable Cox proportional hazard regression analysis was used to assess assay performance in predicting biochemical failure-free survival (BFFS) and metastasis-free survival (MFS)., Results: Gene expression analysis was carried out in 248 patients from the independent validation cohort and the Metastatic Assay applied. Ten-year MFS was 72% for Metastatic Assay positive patients and 94% for Metastatic Assay negative patients [HR = 3.21 (1.35-7.67); P = 0.003]. On multivariable analysis the Metastatic Assay remained predictive for development of distant metastases [HR = 2.71 (1.11-6.63); P = 0.030]. The assay retained independent prognostic performance for MFS when assessed with the Cancer of the Prostate Assessment Score (CAPRA) [HR = 3.23 (1.22-8.59); P = 0.019] whilst CAPRA itself was not significant [HR = 1.88, (0.52-6.77); P = 0.332]. A high concordance [100% (61.5-100)] for the assay result was noted between two separate foci taken from 11 tumours, whilst Gleason score had low concordance., Conclusions: The Metastatic Assay demonstrated significant prognostic performance in patients treated with radical radiotherapy both alone and independent of standard clinical and pathological variables. The Metastatic Assay could have clinical utility when deciding upon treatment intensification in high-risk patients. Genomic and clinical data are available as a public resource., (© The Author 2017. Published by Oxford University Press on behalf of the European Society for Medical Oncology.)

Pain is a common presenting and often persistent symptom for children with rheumatological disease. Pain is not clearly related to disease severity in children with inflammatory juvenile idiopathic arthritis, and presentations of non-inflammatory musculoskeletal pain are common but there is limited evidence to guide management. Pain assessment must extend beyond measures of pain severity to more fully evaluate characteristics of pain, functional impact and psychosocial effects and family interactions. Evaluation of mechanisms of joint pain in adults has identified potential treatment targets, but additional studies are required as the acute and long-term impacts of pain and injury change during postnatal development. Genotyping, sensory evaluation and neuroimaging may better characterize chronic musculoskeletal pain, identify high-risk groups and/or provide additional outcome measures to monitor disease and treatment progress. An integrated approach to management is required to effectively select and target interventions, reduce pain and disability and improve long-term outcome., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

We have determined the mitochondrial genotype of liver fluke present in Bison (Bison bonasus) from the herd maintained in the Bialowieza National Park in order to determine the origin of the infection. Our results demonstrated that the infrapopulations present in the bison were genetically diverse and were likely to have been derived from the population present in local cattle. From a consideration of the genetic structure of the liver fluke infrapopulations we conclude that the provision of hay at feeding stations may be implicated in the transmission of this parasite to the bison. This information may be of relevance to the successful management of the herd., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Many clinical cases of chronic pain exhibit both neuropathic and inflammatory components. In contrast, most animal models of chronic pain focus on one type of injury alone. Here we present a novel combined model of both neuropathic and inflammatory pain and characterise its distinctive properties. This combined model of chronic constriction injury (CCI) and intraplantar Complete Freund's Adjuvant (CFA) injection results in enhanced mechanical allodynia, thermal hyperalgesia, a static weight bearing deficit, and notably pronounced spontaneous foot lifting (SFL) behaviour (which under our conditions was not seen in either individual model and may reflect ongoing/spontaneous pain). Dorsal root ganglion (DRG) expression of Activating Transcription Factor-3 (ATF-3), a marker of axonal injury, was no greater in the combined model than CCI alone. Initial pharmacological characterisation of the new model showed that the SFL was reversed by gabapentin or diclofenac, typical analgesics for neuropathic or inflammatory pain respectively, but not by mexiletine, a Na(+) channel blocker effective in both neuropathic and inflammatory pain models. Static weight bearing deficit was moderately reduced by gabapentin, whereas only diclofenac reversed mechanical allodynia. This novel animal model of chronic pain may prove a useful test-bed for further analysing the pharmacological susceptibility of complicated clinical pain states., (Copyright © 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.)

Fat mass and obesity associated gene (Fto), also known as Fatso, is a member of the Fe-II and 2-oxoglutarate-dependent dioxygenase superfamily. Recent studies in humans and rodents suggest that Fto is involved in food intake regulation and lipid metabolism, whereas single nucleotide mutations in the Fto gene are associated with obesity and type 2 diabetes. The Fto gene is highly conserved from green algae to humans, but little is known about the avian Fto gene or protein. The objectives of the current study were to clone full-length chicken Fto cDNA and to determine the effect of age or feeding status on Fto expression. With the use of rapid amplification of cDNA ends, the full-length chicken Fto cDNA was cloned and found to share 63% to 66% homology with the mammalian Fto nucleotide sequence. Several regions of the chicken Fto protein, including the substrate (2-oxoglutarate) binding domains, were found to be identical to mammalian Fto protein. Western blotting with anti-human Fto antibody and reverse transcription PCR studies showed that Fto protein and gene were ubiquitously expressed in various tissues of the chicken. With the use of quantitative PCR, Fto mRNA levels were found to be higher in liver and skeletal muscle of 8-wk-old chickens than in 4-wk-old chickens. In addition, alterations in feeding status resulted in significant changes in Fto mRNA and Fto protein expression in the liver but not in skeletal muscle and adipose tissue of broiler chickens. Taken together, our data suggest that Fto probably plays a significant role in liver function and energy metabolism in the chicken., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Hares (Lepus europeanus) sharing pasture with cattle from six locations in the Netherlands were examined for the presence of liver fluke (Fasciola hepatica) and shown to have prevalences of infection ranging from 0 to 41%. The mitochondrial haplotypes of liver flukes present in the hare populations were determined and compared with those found in cattle from a farm where triclabendazole resistance has been reported. Phylogenetic analysis indicated that the flukes present in the hares belonged to the same clades as those present in the cattle. A consideration of the life cycle of the liver fluke and the seasonal breeding pattern and ecology of hares supports the suggestion that hares may act as a refugia for liver fluke and as a vector for the spread of drug-resistant genotypes., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Cancer-induced bone pain (CIBP) is a major clinical problem with up to 85% of patients with bony metastases having pain, often associated with anxiety and depression, reduced performance status, and a poor quality of life. Malignant bone disease creates a chronic pain state through sensitization and synaptic plasticity within the spinal cord that amplifies nociceptive signals and their transmission to the brain. Fifty per cent of patients are expected to gain adequate analgesia from palliative radiotherapy within 4-6 weeks of treatment. Opioid analgesia does make a useful contribution to the management of CIBP, especially in terms of suppressing tonic background pain. However, CIBP remains a clinical challenge because the spontaneous and movement-related components are more difficult to treat with opioids and commonly used analgesic drugs, without unacceptable side-effects. Recently developed laboratory models of CIBP, which show congruency with the clinical syndrome, are contributing to an improved understanding of the neurobiology of CIBP. This chronic pain syndrome appears to be unique and distinct from other chronic pain states, such as inflammatory or neuropathic pain. This has clear implications for treatment and development of future therapies. A translational medicine approach, using a highly iterative process between the clinic and the laboratory, may allow improved understanding of the underlying mechanisms of CIBP to be rapidly translated into real clinical benefits in terms of improved pain management.

Significant advances in the assessment and management of acute pain in children have been made, and are supported by an increase in the availability and accessibility of evidence-based data. However, methodological and practical issues in the design and performance of clinical paediatric trials limit the quantity, and may influence the quality, of current data, which lags behind that available for adult practice. Collaborations within research networks, which incorporate both preclinical and clinical studies, may increase the feasibility and specificity of future trials. In early life, the developing nervous system responds differently to pain, analgesia, and injury, resulting in effects not seen in later life and which may have long-term consequences. Translational laboratory studies further our understanding of developmental changes in nociceptor pathway structure and function, analgesic pharmacodynamics, and the impact of different forms of injury. Chronic pain in children has a negative impact on quality of life, resulting in social and emotional consequences for both the child and the family. Despite age-related differences in many chronic pain conditions, such as neuropathic pain, management in children is often empirically based on data from studies in adults. There is a major need for further clinical research, training of health-care providers, and increased resources, to improve management and outcomes for children with chronic pain.

Background: There is concern that exposure of preterm infants to noxious insults over a prolonged period may have long term effects on their developing nervous system., Aims: To investigate medium and long term effects of heel pricks in infants over the first year of life., Study Design: Study 1-a longitudinal study, 2 days and 4 weeks after heel prick. Study 2-a cross sectional study over the first year of life., Subjects: Study 1-13 healthy preterm (PT) infants. Study 2-63 full term (FT) and 62 PT infants, divided into 3 timed groups (0-20, 21-37 and 38-52 weeks postterm and corrected for prematurity)., Outcome Measures: Threshold responses (flexion withdrawal (FWR) , gross body movements (GBM) and grimace (G)) to increasing mechanical force applied with Von Frey filaments., Results: Study 1-Thresholds were all significantly lower (more sensitive) from the pricked heel compared to the contralateral side at 2 days and 4 weeks. Study 2-There were significant differences in threshold between PT and FT infants at all time points for both FWR (P=0.001, <0.001, <0.001) and GBM (P=<0.001, <0.001, 0.009 respectively), the preterm infants always being lower. The threshold for the FWR in FT infants steadily increased, but the threshold for the PT infants remained the same. GBM thresholds increased during the year in both FT and PT infants, but were always significantly lower in the ex-preterm group (P<0.012)., Conclusions: Either PT birth or repetitive procedures associated with such birth alters the sensitivity threshold of PT infants compared with FT infants for at least the first year of life.

Objectives: This research identifies the level of specificity of cause-of-injury morbidity data in Australia. The research explores reasons for poor-quality data across different causes-of-injury areas, including a lack of clinical documentation and insufficient detail in the classification system., Methods: The 2002/03 hospital morbidity dataset of 593,079 injury-related hospital admissions was analysed to examine the specificity of coded external cause-of-injury data., Results: While overall specificity appeared high, the cause of 47,660 injuries was not specifically defined according to the code assigned. Only 56% of cases for whom injury was the result of an accidental fall were assigned a specific code to identify the causal detail; 19% were assigned an 'Other Specified' fall code, suggesting a lack of specific code availability; and 25% were assigned an 'Unspecified Fall' code, suggesting a lack of clinical documentation to facilitate code selection., Conclusions: To improve the quality of injury-related hospital morbidity data, two main areas to focus resources are: 1) the development of more specific cause-of-injury codes; and 2) the provision of more detailed documentation from clinicians., Implications: Clinicians and clinical coders need to work together to improve the quality of injury-related coded data through the provision of specific codes and improved clinical documentation. Accurate and comprehensive data pertaining to the circumstances surrounding hospitalised injury events will benefit injury prevention and surveillance initiatives, provide justification for resources related to injury hospitalisation, and assist in external cause research in Australia.

Some opioid-resistant pain conditions can be alleviated by voltage-dependent Na(+) channel blockers such as lamotrigine. The mu-opioid-receptor agonist morphine can modulate cation entry into cells to affect overall cellular excitability, an effect which can in turn be endogenously antagonised by the neuropeptide cholecystokinin (CCK). However, lamotrigine may also modulate cellular excitability by non-specifically blocking voltage-dependent ion channels. We have looked for interactions of lamotrigine with the opioid/CCK pathway within the spinal dorsal horn, to rule out the possibility that lamotrigine may attenuate nociceptive responses via actions on this pathway. Both lamotrigine and the mu-opioid agonist DAMGO inhibited mustard oil-evoked cell firing by approximately 50% compared with control levels. Co-application of CCK8S reversed DAMGO-, but not lamotrigine-induced inhibition of cell firing and this reversal was prevented with the selective CCK(B) receptor antagonist PD 135158. Although lamotrigine inhibited both brush- and cold-evoked cell firing in neuropathic animals, lamotrigine inhibition of mustard oil-evoked cell firing in the same animals was not significantly greater than that observed in controls. These results suggest that the antinociceptive properties of lamotrigine within the spinal dorsal horn are unlikely to be mediated via interactions with the opioid/CCK pathway.

The extracellularly recorded electrophysiological activity of single multireceptive dorsal horn neurons was markedly increased by ionophoretic administration of vasoactive intestinal polypeptide (VIP) or pituitary adenylate cyclase activating polypeptide (PACAP)-38. Some cells responded selectively to PACAP-38 (suggesting mediation by a PACAP receptor), whereas others responded to both VIP and PACAP-38 (suggesting a VIP1 and/or VIP2 receptor). Most non-nociceptive cells were unaffected by PACAP-38 and all were unaffected by VIP. The selectivity of VIP/PACAP receptor antagonists was established on cloned rat VIP1, VIP2 and PACAP receptors in vitro before their utilization to indicate the likely involvement of VIP1, and possibly PACAP receptors, in VIP- and PACAP-38-mediated responses of dorsal horn neurons. The VIP/PACAP receptor antagonists inhibited responses of multireceptive cells to sustained innocuous (brush) and noxious (mustard oil) stimuli, with a selectivity suggesting the involvement of VIP1 and PACAP receptors, although the participation by VIP2 receptors cannot be excluded. These data implicate both VIP and PACAP in regulating the basal responsiveness of multireceptive dorsal horn neurons to sensory stimuli.

tat protein, a human immunodeficiency virus (HIV) gene product that functions as a transactivator for HIV replication, is known to be secreted extracellularly by infected cells. To determine the potential role of tat in the dissemination of HIV into extravascular tissue, this protein was examined for its ability to activate human endothelial cells. The results show that tat does indeed stimulate endothelial cells. This is evidenced by their expression of the endothelial-leukocyte adhesion molecules, E-selectin, critical for the initial binding of leukocytes to the blood vessel wall, and their increased synthesis of interleukin-6 (IL-6), a cytokine known to enhance endothelial cell permeability. Furthermore, tat acts synergistically with low concentrations of tumor necrosis factor-alpha to enhance IL-6 secretion. These data suggest that extracellular tat protein secreted or released into the microenvironment may contribute significantly to the determination of specific sites of leukocyte binding to blood vessels, to transmigration into tissue, and to eventual dissemination of HIV-infected cells or free virions into tissue.

Previous evidence indicated that brief nociceptive responses of neurons in laminae IV/V of both rat and cat dorsal horn are more readily inhibited by antagonists at NK2 rather than at NK1 neurokinin receptors. Further support for a role of spinal NK2 receptors in nociception has been provided from experiments assessing modulation of the nociceptive flexor reflex by tachykinins and activation of dorsal horn neurons by brief application of capsaicin to afferents. The present experiments were designed to compare the contribution of NK1 and NK2 receptors in dorsal horn to the sustained neuronal activity induced by peripheral application of the chemical algogen mustard oil (reported to be a selective activator of C afferents). In nearly all of the multireceptive laminae IV/V neurons tested, a selective NK2 receptor antagonist L 659,874 inhibited previously established mustard oil-induced activity. In contrast, two selective NK1 receptor antagonists L 668,169 and GR 82334 were only rarely effective. These results further underline the apparent importance of NK2 receptors in spinal nociceptive processing. NK1 receptors do not appear to play a major role in the present experimental protocol, but they may of course do so under different circumstances.

Previous evidence indicated that NK2 rather than NK1 receptors play a central role in mediating the electrophysiological responses of dorsal horn neurons to brief cutaneous stimuli such as noxious heat (but not noxious pinch) and moderately sustained stimuli such as mustard oil, topically applied over 10-20 min. The present experiments were designed to investigate, by in situ hybridisation histochemistry, a delayed genomic response in dorsal horn neurons (the expression of preprodynorphin mRNA induced by intraplantar carrageenan injection) and explore the role of NK1 and NK2 receptors in mediating this response. In anaesthetised rats with bilateral intraplantar injections of carrageenan, neurokinin receptor antagonists were administered unilaterally by prolonged ionophoresis into the superficial dorsal horn. The marked increase in preprodynorphin mRNA expression elicited by carrageenan was inhibited (both in terms of number of expressing cells and their level of expression) by NK2 but not NK1 antagonists.

Cortisol is converted to the inactive glucocorticoid, cortisone, in several tissues by 11 beta-hydroxysteroid dehydrogenase (11 beta HSD). We have recently measured 11 beta HSD activity in cultured human granulosa-lutein cells recovered from patients undergoing in-vitro fertilisation and embryo transfer (IVF-ET). We now report an association between the outcome of IVF-ET and 11 beta HSD activity in these cells. Of the 64 patients studied, 32 had detectable 11 beta HSD activity and none became pregnant; whereas 76% of the remaining "11 beta HSD-negative" patients achieved pregnancies. Hence 11 beta HSD activity may predict the outcome of IVF-ET.

A new method is described for investigating the killing of Staphylococcus aureus by human phagocytic cells. The radioassay is based on the principle that only viable bacteria synthesize DNA and incorporate [3H]thymidine. Phagocytes are incubated with bacteria and then disrupted by a single freeze-thaw cycle. The uptake of tritiated thymidine by the remaining organisms is a measure of the killing ability of the phagocytes. The technique is simple, sensitive, rapid and requires small volumes of blood. It can be semiautomated and uses equipment readily available in an immunology laboratory and is therefore suitable for routine investigations of leucocyte function. It is likely that the technique could form the basis for measuring kill by phagocytes of any rapidly dividing organism. A time course and a normal range have been evaluated for the bactericidal capacity of 26 normal individuals.

Hemoglobin, hemin, and ferric ion (Fe) were shown to reverse peritoneal exudate cell (PEC)-mediated suppression of concanavalin A-elicited murine spleen cell activation. Titration of hemoglobin and hemin relative to Fe showed a direct relationship between Fe content and reversal of PEC suppression. Indomethacin enhanced the capacity of all three compounds to abrogate PEC suppression on the order of five- to eight-fold. The capacity of endogenous Fe-containing substances as hemoglobin and its catabolites, e.g., hemin, to modulate macrophage expression may be of special significance at sites of inflammation.

The relative ease of tolerizing IgM-bearing versus IgG-bearing B cells was investigated. Previous work had shown that IgG-bearing trinitrophenyl (TNP)-specific B cells from mice primed and boosted with TNP-keyhole limpet hemocyanin (TNP-KLH) are highly susceptible to tolerization in vitro by TNP presented on an unrelated carrier. TNP-OVA was used as tolerogen, as it may represent a more general class of tolerogens than those which are nonmetabolizable or immunoglobulin containing. This study showed that highly primed B cells are tolerizable in vivo using TNP-OVA, with the IgG response to TNP-KLH easier to tolerize than the IgM response. To determine if the ease of tolerization of the IgG response in vivo was due to intrinsic differences in B-cell precursors of the IgM and IgG responses, tolerance was performed in vitro with B cells of defined surface isotypes. A T-independent antigen, TNP-endotoxin, was employed to minimize T-cell effects. At least 10 times as much TNP-OVA was required to tolerize B cells bearing the IgM surface isotype than those with the IgG surface isotype. Thus, the ease of inhibition of the IgG response as compared to the IgM response in vivo by preexposure to TNP-OVA may be at least partially explained by inherent differences in IgM and IgG B-cell precursors.

Normal, nonimmune adult serum is known to inhibit in vitro immune responses when present in sufficient amounts. The significance of inhibition of the immune response by serum, however, is not known. Previous work suggested that normal mouse plasma or serum (NMS) was selectively more inhibitory to nonantigen-specific (e.g., polyclonal) as compared to antigen-specific responses. This led to the hypothesis that constituents of serum (or plasma) may serve naturally to minimize the polyclonal type of antibody response, preserving immune specificity. The present study further examined the effect of NMS on polyclonal versus antigen-specific antibody responses. Under the in vitro assay conditions used, 0.5% NMS supported bacterial endotoxin (ET)-induced mitogenic and polyclonal B lymphocyte responses, antigen (SRBC, TNP-KLH)-specific antibody (IgM, IgG) responses, and antigen-induced or -specific T-lymphocyte proliferative responses, while 5% NMS inhibited all of these responses. However, antigen-specific T-lymphocyte responses could be restored by a 10-fold increase in the antigen concentration and antigen-specific antibody responses could be restored by the addition of ET (10 micrograms/ml) as adjuvant. On the other hand, the mitogenic response to ET remained suppressed regardless of ET concentration. Thus, despite significant reduction of the mitogenic and polyclonal properties of ET in 5% NMS (greater than 70% suppression), sufficient antigenic stimuli permitted optimal specific T- and B-cell responses. Many naturally occurring antigens, e.g., bacterial, fungal, and viral, have inherent B-cell mitogenic and polyclonal activity in addition to adjuvanticity and the presence of the serum inhibitory factor may serve to minimize their indiscriminate polyclonal stimulation of antibody.

Lymphocyte-mediated lysis of target cells grown as monolayers in microtiter wells is readily quantitated by an assay measuring the 86Rb incorporated after attaining isotopic equilibrium. Lysis of fibroblasts by allogeneic lymphocytes sensitized by skin grafts and of tumor cells by syngeneic spleen cells sensitized by intraperitoneal tumor inoculation were readily detected. Weakly cytolytic lymphocyte populations can be assayed by increasing incubation times to 48 h or longer. A potential problem, 86Rb incorporation by lymphocytes sticking to residual target cells, was controlled by comparing 86Rb incorporation by targets incubated with non-immune lymphocytes. Results by 86Rb incorporation were identical to those determined by microscopic counting or 51Cr release. 86Rb incorporation assays should be considered as an alternate to 51Cr release techniques, especially in those experimental systems where the cytolytic potential of a lymphocyte population is so low that lysis can be detected only after long incubation times and/or when the spontaneous release of 51Cr is prohibitively high.

The capacity to interfere with tolerance induction in primed B cells was examined. Previous work had shown that TNP-specific splenic B cells from mice primed and boosted with TNP-KLH are highly susceptible to in vitro tolerization upon a brief exposure to TNP on a carrier unrelated to KLH. In the present work it was found that tolerance induction in these primed B cells could be partially disrupted by addition of the Fc fragment of immunoglobulin, a B-cell mitogen, and adjuvant, during exposure of the B cells to tolerogen. Addition of Fc fragments prepared by papain digestion of human IgG interfered with tolerization routinely in approximately 30-60% of the spleen cells susceptible to tolerogen. Addition of whole IgG or Fab fragments had no effect on tolerance induction. As little as 5 micrograms/ml of the Fc fragment preparation significantly interfered with tolerization and 32-64 micrograms/ml was optimal. Disruption of tolerization was most effective when the Fc fragment was added to the spleen cells either 4 hr prior to tolerogen or simultaneously with tolerogen; addition of the Fc fragment 4 hr after exposure to tolerogen was significantly less effective. Disruption of tolerization by the Fc fragment was not through polyclonal activation of B cells, as antigen was required for generation of significant numbers of PFC to TNP. Also, disruption was not through expansion of low avidity clones of B cells insusceptible to tolerogen, as the avidity of the antibody produced with and without Fc fragments present was approximately the same. These results show that the Fc fragment of IgG can partially interfere with tolerization of primed B cells. The manner in which Fc fragments may function to prevent tolerization through its lymphoid cell stimulatory capacities is discussed.