The relationship between prescription rates of oral corticosteroids for respiratory diseases and deprivation in England

Respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD), are common in England with the worst respiratory outcomes observed in the most deprived areas. There is limited published research to establish whether the rate of oral corticosteroid (OCS) prescribing for asthma and COPD is linked to levels of deprivation. This study carried out a multivariable regression analysis of publicly available data and found that deprivation is associated with a statistically significant increase in the proportion of patients receiving an OCS prescription for asthma or COPD at a GP practice level (p < 0.001). The model estimated that the proportion of prescriptions is 1.88% (95% CI 1.83% to 1.92%) and 2.84% (95% CI 2.70% to 2.98%) for the least deprived GP practice and the most deprived GP practice, respectively. This study lays the groundwork for future research using individual patient level data to consider the impact of variation in OCS prescribing rates.

Predictors of left ventricular ejection fraction in high-risk percutaneous coronary interventions

Revascularization completeness after percutaneous coronary intervention (PCI) is associated with improved long-term outcomes. Mechanical circulatory support [intra-aortic balloon pump (IABP) or Impella] is used during high-risk PCI (HR-PCI) to enhance peri-procedural safety and achieve more complete revascularization. The relationship between revascularization completeness [post-PCI residual SYNTAX Score (rSS)] and left ventricular ejection fraction (LVEF) in HR-PCI has not been established. We investigated LVEF predictors at 90 days post-PCI with Impella or IABP support. Individual patient data (IPD) were analyzed from PROTECT II (NCT00562016) in the base case. IPD from PROTECT II and RESTORE-EF (NCT04648306) were naïvely pooled in the sensitivity analysis. Using complete cases only, linear regression was used to explore the predictors of LVEF at 90 days post-PCI. Models were refined using stepwise selection based on Akaike Information Criterion and included: treatment group (Impella, IABP), baseline characteristics [age, gender, race, New York Heart Association Functional Classification, LVEF, SYNTAX Score (SS)], and rSS. Impella treatment and higher baseline LVEF were significant predictors of LVEF improvement at 90 days post-PCI (p ≤ 0.05), and a lower rSS contributed to the model (p = 0.082). In the sensitivity analysis, Impella treatment, higher baseline LVEF, and lower rSS were significant predictors of LVEF improvement at 90 days (p ≤ 0.05), and SS pre-PCI contributed to the model (p = 0.070). Higher baseline LVEF, higher SS pre-PCI, lower rSS (i.e. completeness of revascularization), and Impella treatment were predictors of post-PCI LVEF improvement. The findings suggest potential mechanisms of Impella include improving the extent and quality of revascularization, and intraprocedural ventricular unloading.

Reducing Unplanned Intubations in the Neonatal Intensive Care Unit After Children's Surgery: A Quality Improvement Project

BACKGROUND

Unplanned intubation following children's surgery is associated with increased postoperative mortality. In response to being a National Surgical Quality Improvement Program - Pediatric (NSQIP-P) high outlier for postoperative unplanned intubation, we aimed to reduce postoperative unplanned intubation events by 25% in one year.

METHODS/INTERVENTION

A multidisciplinary team of stakeholders was assembled in 2018. Most unplanned intubation events occurred in the neonatal intensive care unit (NICU). Based on apparent causes of unplanned intubations identified in case reviews, an extubation readiness checklist and a postoperative pain management guideline emphasizing non-opioid analgesics were implemented for NICU patients in September 2019. Postoperative unplanned intubation events were tracked prospectively and evaluated using quality improvement statistical process control methods.

RESULTS

Unplanned intubations in the NICU decreased from 0.27 to 0.07 events per patient in the post-intervention group (September 2019-June 2022, n = 145) compared to the pre-intervention group (January 2016-August 2019, n = 200), representing a 76% reduction. Postoperative opioid administration decreased significantly, while acetaminophen usage increased significantly over time. Balancing measures of postoperative pneumonia rate (1.5% vs 0.0%, p = 0.267) and median hospital length of stay [40 (IQR 51) days vs 27 (IQR 60), p = 0.124] were not different between cohorts. The 30-day mortality rate for postoperative patients in the NICU significantly declined [6.5% (n = 13) vs 0.7% (n = 1), p < 0.001].

CONCLUSIONS

Postoperative unplanned intubation rates for NICU patients decreased following a quality improvement effort focused on opioid stewardship and extubation readiness.

TYPE OF STUDY

Prospective Quality Improvement.

LEVEL OF EVIDENCE

Level III.

Assessing the Cost and Resource Use Impact of Implantable Cardiac Defibrillator Shocks in the UK CareLink Population

Objective

High voltage devices (implantable cardiac defibrillators (ICDs) and cardiac resynchronization therapy defibrillators referred to jointly as ICDs) reduce rates of sudden cardiac death in patients with cardiovascular disease. However, shocks from ICDs may be associated with healthcare resource use (HCRU) and costs. The aim of this study was to estimate the costs associated with both appropriate and inappropriate shocks from ICDs.

Methods

Patients with appropriate and inappropriate shocks from ICDs were identified via CareLink data from Liverpool Heart and Chest Hospital between March 2017 and March 2019. The devices were SmartShock activated, with anti-tachycardia pacing. Costs were estimated according to the dominant episode of healthcare, from an NHS payer perspective.

Results

There were 2445 patients on the CareLink system with ICDs. Over the two-year period, HCRU data from 143 shock episodes among 112 patients were reported. The total cost for all shocks was £252,552 with mean costs of £1608 and £2795 for appropriate and inappropriate shocks respectively. There was substantial variation in HCRU between shock episodes.

Conclusion

While there was a low rate of inappropriate shocks from ICDs, there were still substantial HCRU and costs incurred. In this study, the specific HCRU was not costed independently, meaning the costs reported are likely to be a conservative estimate. Whilst every attempt to reduce shocks should be made, appropriate shocks cannot be avoided. Strategies to reduce the incidence of inappropriate and unnecessary shocks should be implemented to reduce overall health care costs associated with ICDs.

Playing Hard-to-Get: A New Look at an Old Strategy

According to dating folklore, playing "hard-to-get" is an effective strategy for attracting prospective mates. However, some research suggests that this strategy could backfire if it leads prospective mates to withhold their attraction in return. The present research aimed to review the scope of research on the link between playing hard-to-get - i.e., appearing uncertain in one's interest and/or difficult to attract - and romantic or sexual outcomes. A scoping search was conducted in the electronic databases of PsycINFO, Sociology Source Ultimate, Anthropology Plus, and Academic Search Ultimate using key words related to playing hard-to-get in the context of dating. A total of 18 studies were included in the review. Research suggests that playing hard-to-get may work if optimal levels of perceived uncertainty and difficulty are achieved. Additional variables were identified as being important when evaluating the tactic's efficacy. These include the pursuer's own level commitment to the pursued partner and aversion to uncertainty, and both the pursuer and pursued partners' gender and attachment styles. Directions for future research and the relevance of sociocultural norms in dating are discussed. Keywords: playing hard-to-get, dating, romantic relationships, mating strategy, attraction.

An anchored matching-adjusted indirect comparison of fixed-dose combination calcipotriol and betamethasone dipropionate (Cal/BDP) cream versus Cal/BDP foam for the treatment of psoriasis

OBJECTIVES

To undertake a comparison of Cal/BDP cream versus foam for the treatment of plaque psoriasis, with cross-trial population differences accounted for.

MATERIALS AND METHODS

An anchored matching-adjusted indirect comparison was undertaken, using individual patient data for Cal/BDP cream and published aggregated data for Cal/BDP foam. Altogether, 11 outcomes were analyzed, including PGA success, mPASI75, DLQI-related outcomes and treatment satisfaction across numerous domains. For each outcome an odds ratio or mean difference was calculated to represent the relative efficacy of Cal/BDP cream versus foam. Methods were guided by NICE Decision Support Unit recommendations.

RESULTS

After adjustment, baseline characteristics were balanced across treatment arms in each analysis. There were no statistically significant differences in PGA success, mPASI75 or DLQI outcomes between Cal/BDP cream and foam when they were compared after their recommended treatment durations (8 weeks for cream and 4 weeks for foam). For treatment satisfaction after 1 week of treatment, Cal/BDP cream was significantly superior to the Cal/BDP foam in all but one domain of the questionnaire.

CONCLUSIONS

Cal/BDP cream and Cal/BDP foam have equivalent efficacy and HRQoL (measured in DLQI) outcomes when used for the topical treatment of plaque psoriasis at their recommended treatment durations. A comparison of treatment satisfaction assessments after 1 week of treatment demonstrated that patients find Cal/BDP cream to be more convenient than foam.

Early childhood stress responses to psychosocial stressors: The state of the science

The aim of this systematic review was to better understand whether and to what extent psychosocial stressors are associated with hypothalamic-pituitary-adrenal axis or autonomic nervous system stress responses in young children (1-6 years of age). Studies were classified by psychosocial stressors from the ecobiodevelopmental model: social and economic resources, maternal mental health, parent-child relationships, and the physical environment. Of the 2388 identified studies, 32 met full inclusion criteria, including over 9107 children. Child physiologic stress responses were measured as hair and urinary cortisol and cortisone, salivary diurnal and reactive cortisol, salivary reactive alpha-amylase, and respiratory sinus arrhythmia. There were 107 identified relations between psychosocial stressors and physiologic stress responses. Nearly two thirds of these relations suggested that children have dysregulated stress responses as either significantly blunted (n = 27) or increased (n = 37); 43 relations were not significant. Children most consistently had significantly dysregulated stress responses if they experienced postnatal maternal depression or anxiety. Some reasons for the mixed findings may be related to characteristics of the child (i.e., moderators) or stressor, how the stress response or psychosocial stressor was measured, unmeasured variables (e.g., caregiving buffering), researcher degrees of freedom, or publication bias.

Indirect COVID-19 health effects and potential mitigating interventions: Cost-effectiveness framework

Background

The COVID-19 pandemic led to important indirect health and social harms in addition to deaths and morbidity due to SARS-CoV-2 infection. These indirect impacts, such as increased depression and substance abuse, can have persistent effects over the life course. Estimated health and cost outcomes of such conditions and mitigation strategies may guide public health responses.

Methods

We developed a cost-effectiveness framework to evaluate societal costs and quality-adjusted life years (QALYs) lost due to six health-related indirect effects of COVID-19 in California. Short- and long-term outcomes were evaluated for the adult population. We identified one evidence-based mitigation strategy for each condition and estimated QALYs gained, intervention costs, and savings from averted health-related harms. Model data were derived from literature review, public data, and expert opinion.

Results

Pandemic-associated increases in prevalence across these six conditions were estimated to lead to over 192,000 QALYs lost and to approach $7 billion in societal costs per million population over the life course of adults. The greatest costs and QALYs lost per million adults were due to adult depression. All mitigation strategies assessed saved both QALYs and costs, with five strategies achieving savings within one year. The greatest net savings over 10 years would be achieved by addressing depression ($242 million) and excessive alcohol use ($107 million).

Discussion

The COVID-19 pandemic is leading to significant human suffering and societal costs due to its indirect effects. Policymakers have an opportunity to reduce societal costs and health harms by implementing mitigation strategies.

Mother and father depression symptoms and child emotional difficulties: a network model

Introduction

Enhancing understanding of depression symptom interactions between parents and associations with subsequent child emotional difficulties will inform targeted treatment of depression to prevent transmission within families.

Objectives

To use a network approach to identify ‘bridge’ symptoms that reinforce mother and father depression, and whether bridge symptoms, as well as other symptoms, impact subsequent child emotional difficulties.

Methods

Symptoms were examined using two unregularized partial correlation network models. The study included 4,492 mother-father-child trios from a prospective, population-based cohort in the United Kingdom. Mother and father reports of depression symptoms were assessed when the child was twenty-one months old. Child emotional difficulties were reported by the mother at ages nine, eleven and thirteen years.

Results

Bridge symptoms mutually reinforcing mother and father depression symptoms were feelings of guilt and self-harm ideation, whereas anhedonia acted as a bridge from the father to the mother, but not vice-versa (fig.1, network 1). The symptom of feelings of guilt in mothers was the only bridge symptom which directly associated with child emotional difficulties. Other symptoms that directly associated with child emotional difficulties were feeling overwhelmed for fathers and anhedonia, sadness, and panic in mothers (fig.1, network 2).

Conclusions

Specific symptom interactions are central to the co-occurrence of depression symptoms between parents. Of interest, only one of the bridge symptoms associated with later child emotional difficulties. In addition, specific symptom-to-child outcomes were identified, suggesting that different symptoms in mothers and fathers are central for increased vulnerability in children.

Disclosure

No significant relationships.

A Quality Improvement Approach to Decreasing Postdischarge Acute Care Reuse Among Children With Asthma

OBJECTIVES

To reduce 7-day acute care reuse among children with asthma after discharge from an academic children's hospital by standardizing the delivery of clinical care and patient education.

METHODS

A diverse group of stakeholders from our tertiary care children's hospital and local community agencies used quality improvement methods to implement a series of interventions within inpatient, emergency department (ED), and outpatient settings. These interventions were designed to improve admission, inpatient care, and discharge processes for children hospitalized because of asthma and included a focus on (1) resident education, (2) patient access to medication and asthma education, and (3) gaps in existing asthma clinical care pathways in the ED and ICU. The primary outcome was the rate of 7-day acute care reuse (combined hospital readmissions and ED revisits) after discharge from an index hospitalization for asthma, measured through a monthly review of electronic health record data and compared with a 6-month baseline period of reuse data.

RESULTS

The mean 7-day reuse rate for asthma after discharge was 3.7% during the 6 months baseline period (n = 107) and 1.0% during the 15-month intervention period (n = 302). This included a shift in our median from 3.3% to 0% with an 8-month period of no 7-day reuse.

CONCLUSIONS

An interprofessional quality improvement team successfully achieved and sustained a 73% reduction in mean 7-day asthma-related acute care reuse after discharge by standardizing provider training, care processes, and patient education.

The impact of surgical site infection on hospitalisation, treatment costs, and health-related quality of life after vascular surgery

Surgical site infections (SSI) substantially increase costs for healthcare providers because of additional treatments and extended patient recovery. The objective of this study was to assess the cost and health-related quality of life impact of SSI, from the perspective of a large teaching hospital in England. Data were available for 144 participants undergoing clean or clean-contaminated vascular surgery. SSI development, length of hospital stay, readmission, and antibiotic use were recorded over a 30-day period. Patient-reported EQ-5D scores were obtained at baseline, day 7 and day 30. Linear regressions were used to control for confounding variables. A mean SSI-associated length of stay of 9.72 days resulted in an additional cost of £3776 per patient (including a mean antibiotic cost of £532). Adjusting for age, smoking status, and procedure type, SSI was associated with a 92% increase in length of stay (P < 0.001). The adjusted episode cost was £3040. SSI reduced patient utility between baseline and day 30 by 0.156 (P = 0.236). Readmission rates were higher with SSI (P = 0.017), and the rate to return to work within 90 days was lower. Therefore, strategies to reduce the risk of surgical site infection for high-risk vascular patients should be investigated.

Haemoplasmas: lessons learnt from cats

The haemotropic mycoplasmas (haemoplasmas) are a group of bacteria that can induce anaemia in a wide variety of mammals, including domestic cats and wild felids. Different feline haemoplasma species of varying pathogenicity exist, with the more pathogenic Mycoplasma haemofelis (Mhf) capable of inducing severe haemolytic anaemia, whilst 'Candidatus Mycoplasma haemominutum' (CMhm) and 'Candidatus Mycoplasma turicensis' (CMt) are infrequently associated with clinical disease. Chronic haemoplasma infections are common and cats are frequently infected by two or more haemoplasmas, complicating the clinical picture. The natural route of transmission of haemoplasma infection between cats has not yet been determined; however, experimental transmission has been demonstrated via both oral and parenteral administration of infected blood. To date the haemoplasmas have been unable to be cultured in vitro, and accurate diagnosis is currently reliant on detection of bacterial DNA using PCR assays. Treatment of clinical haemoplasmosis is focussed on supportive care in combination with empirical treatment with antimicrobials (tetracyclines or fluoroquinolones). A significant number of asymptomatic cats are positive for haemoplasma infection. These cats may play a role in the maintenance of haemoplasma infection within a population, and need to be considered when choosing potential blood donors. Use of PCR assays has provided an accurate method of diagnosing haemoplasma infection and quantifying response to therapy, including in non-feline host animals, as presumed zoonotic haemoplasma infections are now being documented. Recent advances in genome sequencing techniques have allowed the whole genome sequences of the feline haemoplasmas Mhf and CMhm to be derived, as well as a number of non-feline haemoplasma species. These data have aided the identification of antigens for use in the development of serological tests, allowed the proteomic study of haemoplasmas and provided clues as to how the haemoplasmas can persist within the host. Future areas of study include investigation of their zoonotic potential, mechanisms of immune system evasion and transmission of these emerging pathogens.

Early immunological changes associated with laryngeal transplantation in a major histocompatibility complex-matched pig model

Laryngeal transplantation is an increasingly viable proposition for patients with irreversible diseases of the larynx. One human transplant has been performed successfully, but many questions remain before routine transplantation can begin. In order to measure the immunological changes in mismatched transplants, it is first necessary to know the immediate combined effects of ischaemia-reperfusion injury (IRI) plus the added insult of major surgery in a fully matched setting. We measured the changes in immunologically active mucosal cells following 3 h of cold ischaemia and 8 h of in situ reperfusion in a major histocompatibility complex (MHC)-matched minipig model (n = 4). Biopsies were prepared for quantitative, multiple-colour immunofluorescence histology. The number of immunologically active cells was significantly altered above (supraglottis) and below (subglottis) the vocal cords following transplantation and reperfusion (P < 0.05, P < 0.001, respectively). However, the direction of the change differed between the two subsites: cell numbers decreased post-transplant in the supraglottis and increased in the subglottis. Despite the statistical evidence for IRI, these changes were less than the large normal inter- and intrapig variation in cell counts. Therefore, the significance of IRI in exacerbating loss of function or rejection of a laryngeal allograft is open to question. Longer-term studies are required.

The larynx as an immunological organ: immunological architecture in the pig as a large animal model

The larynx is a mucosal organ positioned at the divergence of the respiratory and digestive tracts. It is exposed to a wide variety of environmental components, including foreign antigens, tobacco smoke, laryngopharyngeal reflux and pollutants. The mucosal immune system generates either active immune responses or tolerance, depending on the nature of the antigen and we hypothesize that the larynx is important organ for immunological decision-making in the airway. Because the pig is an ideal large animal model in which to explore laryngological research questions, such as those relating to laryngeal transplantation, we investigated the normal mucosal immunology of the porcine larynx. Pig larynges and tracheae were processed and prepared for bright-field microscopy and quantitative, multiple-colour immunofluorescence histology using pig-specific monoclonal antibodies. There was an abundance of immunologically active cells within the mucosa of the larynx and trachea of both the newborn and adult animal. Specifically, major histocompatibility complex class II (MHC class II+) cells, CD4+ and CD8+ cells were identified, although regional differences in numbers were apparent: specifically, the supraglottis contained fewer immunologically relevant cells than other sites sampled. There was a significant correlation between the numbers of MHC class II+ and CD4+ cells indicating co-ordinate regulation and therefore functional local interactions. The presence of such an immunological structure suggests that the larynx may have important functions in respiratory immunology and that it may trigger strong alloresponses after laryngeal transplantation.

Validation of computer-assisted, pixel-based analysis of multiple-colour immunofluorescence histology

Developments in immunohistology allow the routine simultaneous use on tissue sections of three monoclonal antibodies, tagged with different fluorochromes. Such staining can identify seven different cell populations and the limiting factor is rapid, reliable and reproducible analysis. Future reliance on computer-assisted analysis of digitised images depends on validation against manual counting, often viewed as the 'gold standard'. In this study images were digitised from sections of normal porcine skin, inflamed skin and tonsil, simultaneously stained with three monoclonal antibodies. Combinations of staining were quantified by four manual counts and by pixel-based area measurement. On individual images, the correlation between automated and manual measurements was poor. Despite this, the concordance between manual and automated measurements in the means and variances of tissues was good, and both techniques identified the same changes in inflamed versus normal tissues. In addition, pixel-based counting permitted statistical analysis of co-localisation of cell types in tissue sections. We conclude that automated counting is acceptable for the assessment of tissues, is faster and provides less opportunity for observer variation than manual counting. We also demonstrate that the technique is applicable where more than three fluorochromes are used such that manual counting becomes essentially impossible.

Inheritance of superoxide dismutase ( Sod-1) in a perennial x annual ryegrass cross and its allelic distribution among cultivars

Identifying annual ryegrass contamination in perennial ryegrass seed lots has been of major interest in seed-testing laboratories and for seed regulatory agencies in the USA for many years. This study was conducted to characterize a superoxide dismutase locus ( Sod-1) and determine its potential to distinguish cultivated ryegrass species. The inheritance of Sod-1 was evaluated in a three-generation annual x perennial ryegrass mapping population and segregation fitted an expected 1:2:1 ratio for a single locus with two alleles. The molecular form of the Sod-1 locus was determined by H(2)O(2) and KCN inhibitor assays which indicated that the Sod-1, and a second independently segregating Sod-2, locus were both Cu/ZnSod enzymes. The common alleles at the Sod-1 locus were scored in 13 annual and 24 perennial ryegrass cultivars to determine the potential of using this locus for species separation. The Sod-1b allele was homozygous in 98% of perennial ryegrass individuals from 24 cultivars, but those not 100% homozygous for Sod-1b were seed lots with unknown contamination from annual ryegrass. These results indicate that the Sod-1b allele in the homozygous condition is a good indicator of perenniality. All eight annual ryegrass cultivars originating in Europe or Asia had a low frequency of Sod-1b homozygous individuals or none at all. The five cultivars originating in the Western Hemisphere, however, had genotype frequencies for homozygous Sod-1b of up to 56%. The potential of the Sod-1 locus to serve as a test to separate the two growth forms depends on the source of the annual-type contamination.

HTLV type 1 Tax transduction in microglial cells and astrocytes by lentiviral vectors

Infection with human T cell leukemia virus type 1 (HTLV-1) can result in the development of HAM/TSP, a nonfatal, chronic inflammatory disease involving neuronal degeneration and demyelination of the central nervous system. Elevated levels of the proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and IL-1 observed in the cerebrospinal fluid of HAM-TSP patients suggest that cytokine dysregulation within the CNS is involved in neuropathogenesis. HTLV-1 infection and enhanced expression of TNF-alpha by microglial cells, astrocytes, and macrophages has been hypothesized to lead to the destruction of myelin and oligodendrocytes in the CNS. Although the association of HTLV-2 infection and development of neurological disease is more tenuous, HTLV-2 has also been found to be associated with peripheral neuropathies. To investigate the roles of HTLV Tax(1) and Tax(2) in the induction of cytokine disregulation in these cell types, we are currently developing gene delivery vectors based on human immunodeficiency virus type-1 (HIV-1) capable of stably coexpressing the HTLV-1 or -2 tax and eGFP reporter genes in primary human cells. Transduction frequencies of up to 50%, as assessed by eGFP expression, can be achieved in human monocyte-derived macrophages and in explanted cultures of human microglia. Preliminary data suggest that Tax(1) expression is sufficient to up-regulate the proinflammatory cytokine profile in explanted human microglial cells. Future experiments will compare and evaluate the effect of tax(1) and tax(2) gene expression on the cellular proinflammatory cytokine expression profile, as well as demonstrate the effects of transducing human fetal astrocytes and PBMC-derived macrophages.

Mast cell basic fibroblast growth factor in silicosis

To investigate the role of mast cells (MC) and their fibrogenic growth factors in silicosis, we performed quantitative immunohistochemistry for MC tryptase and for basic fibroblast growth factor (bFGF) in lung tissue from silicotic and control subjects. Anti-bFGF antibody was bound to lung MC, basement membrane, endothelial cells, and smooth-muscle cells. Morphometric analysis revealed that the volume density (V(v)) of MC was increased in silicotic lung and that the V(v) of bFGF-positive (bFGF(+)) cells was significantly higher than normal in silicotic lung. Most MC contained bFGF (rho = 0.88, p < 0.001). The V(v) of collagen/reticulin fibers was increased in silicosis and correlated with the V(v) of bFGF(+) cells (rho = 0.81, p < 0.001). Immature silicotic nodules contained bFGF(+) MC throughout the loose array of collagen/reticulin fibers. In large, mature nodules, the density of collagen/reticulin fibers was higher, and bFGF(+) MC were found only in the nodule periphery. Because of this circumferential MC alignment in silicotic nodules, we observed a negative correlation between the V(v) of bFGF(+) MC and the density of collagen/reticulin fibers in silicotic nodules (rho = -0.80, p < 0.001) and between the V(v) of all other nodule-associated cells and the density of collagen/reticulin fibers in the hypocellular nodule centers (rho = -0.84, p < 0.001). We conclude that MC that produce bFGF may play an important role in the development of silicosis.

Detection of beryllium sensitivity using a flow cytometric lymphocyte proliferation test: the Immuno-Be-LPT

Measurement of lymphocyte proliferation to detect hypersensitivity to beryllium (Be-LPT) in vitro is done presently using a method based on tritiated thymidine incorporation. Although this method is sensitive it gives no information on cell viability or responding lymphocyte subsets. We have developed reliable and simple flow cytometric assays for lymphocyte proliferation testing (Immuno-Be-LPT) by combining immunophenotyping with bromodeoxyuridine (BrdU) incorporation or DNA content using propidium iodide (PI) or 4'6'-diimidazolin-2-phenylindole (DAPI). Evaluation of beryllium-induced lymphocyte proliferation in blood cells from seven patients with chronic beryllium disease (CBD) and 120 beryllium workers by both the Bc-LPT and the Immuno-Be-LPT showed agreement between the tests. The Immuno-Bc-LPT provided additional information about the specific type of lymphocytes responding. CD4+ lymphocytes proliferated in response to beryllium in blood samples from all seven CBD individuals and CD8+ lymphocytes proliferated in six of the seven. Four beryllium workers without CBD had positive responses to beryllium primarily in the CD8+ cells. The use of the individual's own plasma supported a greater beryllium or tetanus-induced proliferation of CD4+ lymphocytes when compared to commercial human serum. The response of CD4+ lymphocytes measured in the Immuno-Be-LPT may provide a new marker for the diagnosis of CBD.

Long-term variations of man-made radionuclide concentrations in a bio-indicator Mytilus galloprovincialis from the French Mediterranean coast

Results from a 14-year monitoring (1984-1997) of man-made radionuclide (137Cs and 106Ru) levels in Mytilus galloprovincialis collected monthly on the French Mediterranean coast are presented. In this area sources of man-made radionuclides are on the one hand atmospheric fallout from both the past nuclear testings and the Chernobyl accident and on the other hand discharges from nuclear installations located on the Rhône River banks, especially those from the spent nuclear fuel reprocessing plant in Marcoule. Long-term variations of radionuclide concentrations in Mytilus demonstrated seasonal variations which are linked to the reproductive cycle of these organisms as well as to variations in land-based inputs of man-made radionuclides. A comparative study of these seasonal variations has been carried out with the aid of spectral analysis. Due to differences in released activities and discharge patterns, flow rates appear to govern mainly the 137Cs variations in the Rhône waters, whereas 106Ru variations are driven by the discharges. In the area under the influence of the Rhône outflow, 137Cs variations in mussels are characterized by seasonal variations which are themselves inversely correlated with variations of 137Cs concentrations in Rhône waters. This cyclic component seems to be closely linked to the mussel reproductive cycle. The possible influence of other parameters is discussed.

The role of CD80 and CD86 in enhancing CD8(+) cell suppression of HIV replication

CD8(+) cells activated in the presence of autologous macrophages (Mphi) have an increased ability to suppress HIV replication compared to the same cells stimulated in the absence of Mphi. Blocking the B7 molecules decreases the ability of Mphi to increase CD8(+) cell antiviral activity. In the present study CD8(+) cells exposed to purified forms of both the CD80 and the CD86 molecules during stimulation with anti-CD3 antibodies (Ab) had a greater ability to suppress HIV replication than CD8(+) cells exposed to anti-CD3 Ab alone. The addition of anti-CD86 blocking Ab, but not anti-CD80 blocking Ab, to Mphi decreased their ability to enhance CD8(+) cell suppression of HIV replication. Moreover, anti-CD86 Ab and not anti-CD80 Ab blocked the production of IL-2 by CD8(+) cells stimulated in the presence of Mphi. The incapacity of anti-CD80 Ab to block the enhanced antiviral activity and IL-2 production of CD8(+) cells stimulated in the presence of Mphi was not due to the inability of this Ab to function since anti-CD80 Ab are able to block proliferation of CD8(+) cells cultured in the presence of Mphi. Thus, while both B7 molecules can deliver a costimulatory signal sufficient to increase CD8(+) cell antiviral activity, CD86 appears to be the molecule that serves as the costimulatory molecule on Mphi to enhance CD8(+) cell suppression of HIV replication. The difference in use of CD86 over CD80 molecules on Mphi by CD8(+) cells mediating the antiviral suppressing activity most likely results from a higher number of Mphi expressing the CD86 molecule compared with the CD80 molecule. This information offers a possible therapeutic approach to increase CD8(+) cell anti-HIV response.

CD8+ cell-derived anti-human immunodeficiency virus inhibitory factor

CD8+ cells in human immunodeficiency virus (HIV)-infected individuals develop the ability to control HIV replication not only by destruction of the infected cells but also by controlling the virus in a noncytotoxic fashion that leaves the infected cell functionally intact. The CD8+ noncytotoxic response is mediated by a novel soluble factor known as CD8+ cell antiviral factor (CAF). CAF suppresses HIV replication in the infected cell at the level of viral transcription by interrupting the ability of Tat or host cellular factors to interact with the HIV long terminal repeats. Unlike some strain-specific anti-HIV cytokines, CAF is active against many different virus isolates, including HIV strains that are nonsyncytium- and syncytium-inducing. Of importance, the ability of CD8+ cells to produce CAF and suppress HIV replication plays a critical role in preventing disease progression following HIV infection.

Differential effects of CD28 costimulation on HIV production by CD4+ cells

We have observed that CD28 costimulation of CD4+ cells can have differential effects on HIV replication. Triggering the CD28 molecule on peripheral blood CD4+ cells during stimulation with anti-CD3 Abs enhances virus production following acute infection with HIV. Endogenous virus production in CD4+ cells from HIV-infected individuals is also increased by this procedure. The enhanced virus production occurs equally when anti-CD28 Abs and soluble forms of the natural ligands for CD28, CD80Ig, and CD86Ig are used to trigger CD28 on CD4+ cells during stimulation. This increased virus replication is observed only when the source of CD28 costimulation is removed immediately after stimulation and before infection. Continual exposure of CD4+ cells to anti-CD3 and CD28 Ab beads following acute infection prevents virus production. These findings may have relevance to therapeutic approaches aimed at inhibiting HIV replication by CD28 costimulation.

Differences in HIV replication in CD4+ lymphocytes are not related to beta-chemokine production

CD4+ T lymphocytes from different donors vary in their ability to replicate different isolates of HIV. Beta-chemokines have been shown to reduce the rate of HIV replication in cultured cells. We now demonstrate, using CD4+ cells from 19 different donors, that the variations in viral replication observed in CD4+ lymphocytes are not due to endogenous production of beta-chemokines by the cells. Instead of finding a correlation of high-level beta-chemokine production with low-level replication of virus, we found either no consistent relationship between these two parameters or a correlation between high-level beta-chemokine production and high-level virus replication. This observation was made with both chemokine-sensitive and chemokine-resistant HIV isolates. Thus, other mechanisms appear to be involved in the variability in HIV replication in cultured CD4+ cells.

Virological and immunological features of long-term human immunodeficiency virus-infected individuals who have remained asymptomatic compared with those who have progressed to acquired immunodeficiency syndrome

Infection with the human immunodeficiency virus (HIV) leads to a decrease in CD4(+) T cells and disease progression within a decade of seroconversion. However, a small group of infected people, despite being infected by HIV for 10 or more years, remain clinically asymptomatic and have stable CD4(+) cell counts without taking antiretroviral medication. To determine why these individuals, known as long-term survivors (LTS), remain healthy, the hematological profiles, viral load and properties, HIV coreceptor genotype, and anti-HIV immune responses of these people were compared with those of individuals who have progressed to disease (Progressors) over the same time period. Unlike Progressors, LTS have a low circulating viral load and a low number of HIV-infected cells. These differences in the levels of the viral load were not associated with a dominant biologic viral phenotype, varying growth kinetics of the virus, mutation in the cellular CCR5 gene, or the presence of neutralizing antibodies. Importantly, the difference in viral load could be explained by the enhanced ability of CD8(+) cells from LTS to suppress HIV replication.

Primary CD8+ cells from HIV-infected individuals can suppress productive infection of macrophages independent of beta-chemokines

The productive infection of human monocyte-derived macrophages (Mphi) by HIV was suppressed by primary CD8+ cells from asymptomatic HIV-infected individuals. This anti-HIV response was noncytotoxic; removal of the CD8+ cells from the infected Mphi leads to virus production. CD8+ cells inhibited HIV replication when separated from the infected Mphi by a transwell filter insert, indicating a diffusible factor made by the CD8+ cells suppressed productive infection of Mphi. Three beta-chemokines, which can be secreted by activated CD8+ cells, RANTES (regulated on activation normal T cell expressed and secreted), macrophage inflammatory protein (MIP)-1alpha and MIP-1beta prevented HIV replication in the Mphi cultures. In addition, incubation of acutely infected Mphi with a mixture of neutralizing antibodies to RANTES, MIP-1alpha, and MIP-1beta enhanced virus replication. Nevertheless, neutralization of beta-chemokines with specific antibodies did not abolish the suppression by CD8+ cells of HIV replication in Mphi. Thus, even though beta-chemokines decrease HIV replication in Mphi, these cytokines are not responsible for the ability of CD8+ cells to inhibit HIV production in these cells.

CD28 costimulation increases CD8+ cell suppression of HIV replication

A subset of CD8+ T lymphocytes that expresses CD28, a membrane receptor for B7 differentiation Ags found on APCs, is primarily responsible for the noncytotoxic suppression of HIV replication in CD4+ cells of HIV-infected individuals. Optimal inhibition of HIV production by CD8+ cells occurs after triggering the CD28 molecule on the cells with anti-CD28 Abs during stimulation. Blocking the interaction of the CD28 and B7 molecules with a CTLA4Ig fusion protein abrogates the ability of autologous macrophages to enhance this CD8+ cell antiviral activity. This blocking effect can be reversed by treating the CD8+ cells with anti-CD28 Ab. The increase in antiviral activity following CD28 costimulation correlates with enhanced IL-2 production and IL-2R expression by CD8+ cells. Prevention of IL-2 binding to its receptor, using anti-IL-2 or anti-IL-2R Abs, reduces the ability of CD8+ cells to suppress HIV replication following CD28 costimulation. Importantly, engagement of the CD28 molecule during stimulation of CD8+ cells from individuals with AIDS restored the ability of their cells to suppress HIV replication. Thus, triggering the CD28 molecule during stimulation of CD8+ cells could clinically benefit HIV-infected symptomatic patients.

CD28 costimulation increases CD8+ cell suppression of HIV replication

A subset of CD8+ T lymphocytes that expresses CD28, a membrane receptor for B7 differentiation Ags found on APCs, is primarily responsible for the noncytotoxic suppression of HIV replication in CD4+ cells of HIV-infected individuals. Optimal inhibition of HIV production by CD8+ cells occurs after triggering the CD28 molecule on the cells with anti-CD28 Abs during stimulation. Blocking the interaction of the CD28 and B7 molecules with a CTLA4Ig fusion protein abrogates the ability of autologous macrophages to enhance this CD8+ cell antiviral activity. This blocking effect can be reversed by treating the CD8+ cells with anti-CD28 Ab. The increase in antiviral activity following CD28 costimulation correlates with enhanced IL-2 production and IL-2R expression by CD8+ cells. Prevention of IL-2 binding to its receptor, using anti-IL-2 or anti-IL-2R Abs, reduces the ability of CD8+ cells to suppress HIV replication following CD28 costimulation. Importantly, engagement of the CD28 molecule during stimulation of CD8+ cells from individuals with AIDS restored the ability of their cells to suppress HIV replication. Thus, triggering the CD28 molecule during stimulation of CD8+ cells could clinically benefit HIV-infected symptomatic patients.

Do beta-chemokines have clinical relevance in HIV infection?

The role of beta-chemokines in HIV infection was evaluated. The kinetics of regulated upon activation of normal T cell expressed and secreted, macrophage inflammatory protein-1alpha, and macrophage inflammatory protein 1beta production by stimulated T lymphocytes did not differ substantially between HIV-infected (asymptomatic and with AIDS) and uninfected subjects. Maximal production of these beta-chemokines by activated peripheral blood cells was higher in the infected individuals than in uninfected individuals, but no significant difference was observed between healthy infected subjects and AIDS patients. Evaluation of the effect of HIV replication on beta-chemokine production indicated that acute infection of CD4+ T cells with non-syncytia-inducing (NSI) viruses generally increased beta-chemokine production two to eightfold, whereas with SI strains, it led to decreased production. The sensitivity of an individual's virus to beta-chemokine-mediated inhibition correlated with the NSI virus phenotype and a healthy clinical state. 50% of the AIDS patients, however, had NSI viruses that were sensitive to beta-chemokines. Finally, anti-beta-chemokine-neutralizing antibodies caused a more rapid release of HIV by CD4+ T cells naturally infected by NSI, but not SI, viruses indicating that endogenously produced chemokines can affect HIV production in culture. These findings suggest that beta-chemokines may affect HIV replication when an NSI virus is involved, but provide little evidence that they substantially influence HIV infection and pathogenesis.